Incubation Conditions and Duration

The growth of all genera discussed in this chapter occurs best at 35 C and in the presence of increased C02. Therefore 5 sheep blood and chocolate agars should be incubated in a C02 incubator or candle jar. In addition, Actinobacillus and Cardiobacterium grow best in conditions of elevated moisture a candle jar with a sterile gauze pad moistened with sterile water is ideal for this purpose. Capnocytophaga will grow anaerobically but will not grow in ambient air. Even when optimum growth...

Pathogenesis And Spectrum Of Disease

Aspergillus species are capable not only of causing disseminated infection, as is seen in immunocompromised patients, but also of causing a wide variety of other types of Infections, including a pulmonary or sinus fungus ball, allergic bronchopulmonary aspergillosis, external otomycosis (a fungus ball of the external auditory canal), mycotic keratitis, onychomycosis (infection of nail and surrounding tissue), sinusitis, endocarditis, and central nervous system infection. Most often,...

Info

Persistence of exoerythrocytlc cycle No, but long-term recrudescences are recognized Possible, but usually spontaneous recovery Appearance of parasitized red blood cells size and shape 11 2 to 2 times larger than normal oval to normal may be normal size until ring fills V2 of cell Normal shape size may be normal or slightly smaller 60 of cells larger than normal and oval 20 have irregular, frayed edges Schiiffner's dots (eosinophilic stippling) Usually present in all cells except early ring...

Api20c Aux Yeast System

The API-20C AUX yeast identification system (bio-Merieux, Durham, NC) has perhaps the most extensive computer-based data set of all commercial systems available. The system consists of a strip that contains 20 microcupules, 19 of which contain dehydrated substrates for determining utilization profiles of yeasts. Reactions are compared with growth in the first cupule, which lacks a carbohydrate substrate. Reactions are read and results are converted to a seven-digit biotype profile number. Most...

Automated and Semiautomated Systems

Automated screening systems offer the promise of a large throughput with minimal labor and a rapid turnaround time compared with conventional cultures. However, these advantages may be offset by a substantial cost for the instrumentation. Often these costs can be justified only in laboratories that receive many specimens. Several automated or semiautomated urine screening systems that are either bacterial growth independent or dependent are commercially available. By examining images of...

1

Of interest (i.e., lysine, ornithine, or arginine), and a pH indicator. Organisms are inoculated into the tube medium that is then overlaid with mineral oil to ensure anaerobic conditions. (See Chapter 13) Early during incubation, bacteria utilize the glucose and produce acid, resulting in a yellow coloration of the pH indicator. Organisms that can decarboxylate the amino acid then begin to attack that substrate and produce the amine product, which increases the pH and changes the indicator...

Epidemiology spectrum of disease and antimicrobial therapy

Fee organisms listed in Table 33-1 are part of the formal flora of humans and other animals. As such, V generally are of low virulence and, except for those species associated with periodontal infections. usually only cause infections in humans after introduction into sterile sites following trauma such as bites or manipulations in the oral cavity.1,6'9 The types of infections caused by these bacteria vary from periodontitis to endocarditis (Table 33-2). Three of these organisms, Actinobadllus...

Culture Media And Incubation Requirements

Any of a number of fungal culture media are satisfactory for use in the clinical microbiology laboratory. Most are adequate for the recovery of fungi, and selection is usually left up to each individual laboratory director. Table 50-6 lists various media and the indications for their use. For optimal recovery a battery of media should be used, and the following are recommended 1. Media with and without cycloheximide 2. Media with and without an antibacterial agent. This is for specimens that...

Bone

Diagnosis of certain diseases, including brucellosis, histoplasmosis, blastomycosis, tuberculosis, and leishmaniasis, can sometimes be made only by detection of the organisms in the bone marrow. Brucella spp. can be isolated on culture, as can fungi, but parasitic agents must be visualized in smears or sections made from bone marrow material. Of importance, many of the etiologic agents associated with disseminated infections in patients infected with the human immunodeficiency virus (HTV) may...

Additional Reading

Enterobacter Citrobacter, Serratia, Plesio-monas, and other Enterobaderiaceae, In Murray PR, Baron EJ, Jorgensen JH, et al, editors Manual of clinical microbiology, ed 8, Washington, DC. 2003, ASM Press, Balows A, Truper HG, Dworkin M, et al editors The pro. karyotes. A handbook on the biology of bacteria ecophysiolog isolation, identification, applications, ed 2, New York, 1992, Springer-Verlag. Bockem hl J, Wang JD Yersinia. In Murray PR, Baron EJ, Jorgensen JH, et al,...

Definitive Identification

Various techniques are available for definitive identti fication of anaerobic bacteria. These methods may include the following Pre-reduced anaerobically sterilized (PRAS) bi* chemicals Miniaturized biochemical systems (e.g., API 20Ar bioMerieux, Inc., St. Louis, Mo) Rapid, preformed enzyme detection panels (e& Anldent, bioMerieux, Inc. RapID-ANA II, Ren Inc., Lenexa, Kan BBL Brand Crystal Anaerobe DXj Becton Dickinson and Company Rapid Anaerot Identification Panel, Dade MicroScan, West...

Acquired Resistance Patterns Common To Local Microbial Flos

If resistance to a particular agent Is common, the utility of the agent may be sufficiently limited so that routine testing is not warranted and only more potent antimicrobials are included in the test battery. Conversely, more potent agents may not need to be in the test battery if susceptibility to less potent agents is highly prevalent. ANTIMICROBIAL SUSCEPTIBILITY TESTING METHOD USED Depending on the testing method, some agents do not reliably detect resistance and should not be included in...

Cez

Figure 12-5 A, By the disk diffusion method, antibiotic disks are placed on the surface just after the agar surface was inoculated with the test organism. B, Zones of growth inhibition around various disks are apparent following 16 to 18 hours of incubation. Figure 12-6 Example of a regression analysis plot to establish zone-size breakpoints for defining the susceptible, intermediate, and resistant categories for an antimicrobial agent. In this example, the maximum achievable serum...

J

Figur 10-6 Indirect fluorescent antibody tests for Toxoplasma gondii, IgG antibodies. A, Positive reaction. Br Negative reaction. (Courtesy Meridian, Cincinnati, Ohio.) human immunodeficiency virus (HIV), rubella virus (both IgG and IgM), mycoplasmas, chlamydias Borrelia burgdorferi, Entamoeba histolytica, T. gondii, and many other agents. The introduction of membrane-bound ELISA components has improved sensitivity and ease of use dramatically. Slot-blot and dot-blot assays force the target...

Advantages And Examples Of Commercial System Designs

Commercially available identification systems have largely replaced compilations of conventional test media and substrates prepared in-house for bacterial identification. This replacement has mostly come about because the design of commercial systems has continuously evolved to maximize the speed and optimize the convenience with which all four identification components shown in Figure 7-17 can be achieved. Because laboratory workload has increased, conventional methodologies have had...

Food and Water Borne Outbreaks

The Centers for Disease Control and Prevention report that more than 12,000 cases of food-borne illness occur in the United States each year. Because most of these illnesses are not reported, some estimate that millions of cases occur annually. Eating raw or undercooked fish, shellfish, or meats, and drinking unpasteurized milk increases the risks of certain bacterial, parasitic and viral infections. Many food-borne outbreaks can be traced to poor hygienic practices of food handlers such as not...

Identification Methods

A wide variety of methods and criteria are used to establish a microorganism's identity. These methods usually can be separated into either of two general categories genotypic characteristics and phenotypic characteristics. Genotypic characteristics relate to an organism's genetic makeup, including the nature of the organism's genes and constituent nucleic acids (see Chapter 2 for more information about microbial genetics). Phenotypic characteristics are based on features beyond the genetic...

Qsm

Characteristics of acquired resistance 1. Enzymatic degradation or modification of the antimicrobial agent 2. Decreased uptake or accumulation of the antimicrobial agent 3. Altered antimicrobial target 4. Circumvention of the consequences of antimicrobial action 5. Uncoupling of antimicrobial agent-target interactions and subsequent effects on bacterial metabolism 6. Any combination of mechanisms 1 through 5 Figure 11-8 Overview of common pathways bacteria use to effect antimicrobial...

Direct Visual Examination

All material submitted for culture should always be smeared and examined directly by Gram stain or Other appropriate techniques. In bacterial conjunctivitis, polymorphonuclear leukocytes predominate in viral infection, the host cells are primarily lymphocytes and monocytes. Specimens in which chlamydia is suspected can be stained immediately with monoclonal antibody conjugated to fluorescein for detection of elementary bodies or inclusions. Using histologic stains, basophilic intracytoplasmic...

The Spirochetes

She acquired the disease most likely from the bite of the nymphal form of the Ixodes tick infected with Borrelia burgdorferi. Even though symptoms were not manifest for a few weeks, her description of the initial lesion is consistent with erythema migrans (see Figure 48-3). 2. IFA tests are very sensitive to detect antibodies to B. burgdorferi, but they are known to have a high false-positive rate. Initially the patient's presentation combined with the positive IFA seemed to be enough to treat...

Organism Identification Using Phenotypic Criteria

Phenotypic criteria are based on observable physical or metabolic characteristics of bacteria, that is, identification is through analysis of gene products rather than through the genes themselves. The phenotypic approach is the classic approach to bacterial identification, and most identification strategies are still based on bacterial phenotype. Delineation of some characteristics may require subcellular analysis involving sophisticated instrumentation (e.g., high-performance liquid...

Sinus Tract and Fistulas

Sometimes, a deep-seated infection beneath the skin and subcutaneous soft tissue spontaneously drains itself externally by way of a sinus (channel or cavity) to the skin's surface. Draining sinus tracts are most often associated with a chronic osteomyelitis. Unfortunately, this type of drainage does not usually cure the underlying process, and such sinuses themselves tend to be chronic. The organisms most often involved in sinuses with an underlying osteomyelitis are S. aureus, various...

Inhouse Qa Audits

A facility that does not subscribe to the Q-Probe program may select topics for audits through suggestions from the medical, nursing, or pharmacy staffs complaints from the medical or nursing staff or deficiency or observation noted in the laboratory. Physicians may suggest an audit to measure the transcription accuracy of their orders by nursing unit clerical personnel Nursing administrators may suggest an audit of contaminated urine cultures to access the compliance of the nursing staff in...

Institutional Settings

Diarrheal illness can be a major problem in institutional settings such as day care centers, hospitals, and nursing homes. Because individual hygiene is often difficult to maintain in these settings, coupled with several organisms with relatively low infecting doses such as Shigella and Giardia lamblia, numerous outbreaks of diarrheal illness caused by various organisms have been reported Organisms such as Shigella, Campylobacter jejuni, Giardia lamblia, Cryptosporidium, and rotaviruses have...

Instruments

Equipment logs should contain the following information Instrument name, serial number, and date put in use Procedure and periodicity (daily, weekly, monthly, quarterly) for routine function checks Acceptable performance ranges Instrument function failures, including specific details of steps taken to correct the problems (corrective action) Date and time of service requests and response Date of routine preventive maintenance (PM), which should follow manufacturer's recommendations Maintenance...

Interpretation

Although isolation of M. tuberculosis complex organisms represents infection, the clinician must determine the clinical significance of isolating an NTM in most cases in other words, does the organism represent mere colonization or significant infection Because these organisms greatly in their pathogenic potential, can colonize individual without causing infection, and are ubiquitous in the environment, interpretation of a positive NTM culture is complicated. Therefore, the American thoracic...

Interpretation of Blood Culture Results

Because of the increasing incidence of blood vascular infection caused by bacteria that are normally considered nonvirulent, indigenous microflora of a healthy human host, interpretation of the significance of growth of such bacteria in blood cultures has become increasingly difficult. On one hand, contaminants may lead to unnecessary antibiotic therapy, additional testing and consultation, and increased length of hospital stay. Costs related to false-positive blood culture results (i.e...

Interpretation Of Laboratory Test Results

Interpretation of laboratory test results must be based on knowledge of the normal viral flora in the site sampled, the clinical findings, and the epidemiology of viruses. Serologic testing, in addition to virus detection tests, may be needed to support or refute the association of a virus isolate with a disease state. In general, the detection of any virus in host tissues, CSF, blood, or vesicular fluid is significant. Recovery of adenovirus or mumps virus in urine is usually diagnostic of...

Interpreting And Recording Results

Egg media should have been inoculated with approximately 104. 103, and 102 organisms, respectively. The first dilution should produce semiconfluent growth, and the second and third dilutions should produce countable colonies in each bottle. Because of the retrospective nature of these determinations, dose comparisons must be made between current and previous results to note trends or developing delidendes. Failures may be the result of faulty media, lethal effects of decontamination and...

Ireferences

Bizet C, Tfekaia F, Philippon A In vitro susceptibility of AkaUgenes faecalis compared with those of other Alcatigenes spp. to antimicrobial agents including seven -lacrams, lAntimiaob Chemother 32 907, 1993. 2. Bowman JP, Cavanagh J, Austin JJ, et at Novel Psychrobacter species from Antarctic omithogenlc so s. Int J Syst Bacterial 46 841, 1996. 3. Castagnola E, Tasso L, Conte M, et al Central venous catheter-related infection due to Comamonas acidovoratts in a child with non-Hodgkin's...

Isbn 10 0323030653

BAILEY fr SCOTT'S DIAGNOSTIC MICROBIOLOGY ISBN 13 978-0-8089-2364-0 INTERNATIONAL EDITION, 12th Edition ISBN 10 0-8089-2364-1 Copyright 2007, 2002,1998,1994, 1990,1986,1982,1978,1974,1970,1966,1962 byMosby, Inc., an affiliate of Elsevier Inc. Al rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the...

ItiM hidy

67-year-old woman from the Middle East had total knee arthroplasty of the right knee in 1991 and left inee in 1994. She was seeking medical attention because of pain in her left knee. Her knee was aspirated ffid, 3600 white blood cells per microliter were reported, but no organisms were seen on Gram stain. The culture grew coagulase-negative Staphylococcus from joint fluid Cultured in blood culture bottles after 3 days of incubation. A few tiny, poorly staining gram-negative rods 're present...

Iyj

Multiple resistance leaves few therapeutic choices. Therapy of choice is trimethoprim-sulfamethoxazole. Potential alternatives include minocycline, ticarcillin clavulanic acid, and chloramphenicol Yes, intrinsically resistant to most beta-lactams and aminoglycosides frequently resistant to quinolones See CLSI document M100, Performance Standards for Antimicrobial Susceptibility Testing May be tested by various methods, but profiles obtained with beta-lactams can be seriously misleading No...

Kjz

L wenstein-Jensen (L-J) L-J with RNA L-J with pyruvic acid Middlebrook 7H10 If growth occurs, confirm by AFB smear Mycobacterium Growth Indicator Tube. Figure 45-1 A flowchart for specimen processing for isolation of mycobacteria. Digestion-decontamination procedures should be as gentle as possible, with no more than an overall contamination rate of 5 .5 Overview. Commonly used digestion e ntamina-tion methods are the sodium hydroxide (NaOH) method the Zephiran-trisodium phosphate method, and...

Xvp

Figure 51 -22 Shell vial cell culture tubes and stained coverslips. At the bottom of each shell vial tube under culture medium is a round coverslip with a cell monolayer on the top surface. After incubation, the coverslip is removed, stained, and placed on a microscope slide for fluorescence viewing. Note that two stained coverslips are on the glass slide. ture. It is best used for viruses that require relatively long incubation before producing CPE, such as CMV and VZV. The advantage of shell...

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Figure 2-6 Overview of translation in which mRNA serves as the template for the assembly of amino acids into polypeptides. The three steps include initiation (A), elongation (B and C), and termination (not shown). (i.e., are not transcribed and therefore are not expressed) in the presence of those products. This strategy avoids waste and overproduction of products that are already present in sufficient supply. In this system the product acts as a co-repressor that forms a complex with a...

Jljl

Figure 59-5 The invasion of Shigella and Salmonella into intestinal epithelial cells. (Modified from Sansonetd PJ Genetic and molecular basis of epithelial invasion by Shigella species, Rev Infect Dis 13 suppl 4 S282,1991, University of Chicago Press.) members. Similarly, outbreaks caused by these organisms, as well as hemorrhagic E. coli 0157 H7, have been reported in nursing homes and other extended care facilities. Nosocomial diarrheal illness is also a problem for hospital patients and...

Jllu

Positive hybridization detected by visualization of color Hybridized duplex labeled with acridinium Positive hybridization detected by capturing emission of light Figure 8-2 Reporter molecule labeling of nucleic acid probes and principles of hybridization detection. Use of probes labeled with a radioactive reporter, with hybridization detected by autoradiography (A) probes labeled with biotin-avidin reporter, with hybridization detected by a colorimetric assay (B) probes labeled with...

Keratitis

Keratitis (corneal infection) may be caused by various infectious agents, usually only after some type of trauma produces a defect in the ocular surface. Keratitis should be regarded as an emergency, because corneal perforation and loss of the eye can occur within 24 hours when organisms such as Pseudomonas aeruginosa, Staphylococcus aureus, or HSV are involved. Bacteria account for 65 to 90 of corneal infections. In the United States, S. aureus, S. pneumoniae, and P. aeruginosa account for...

L

Plasmodium vlvax, P. falciparum, P. ovale, and P. malariae are definitely pathogenic tar humans, malaria with P. falciparum being one of the leading causes of death in endemic areas although the host can develop antibody, protection is strain specific and short-lived Malaria can cause a range of symptoms, with life-threatening illness caused by P. falciparum symptoms Include fever, chills, nausea, central nervous system (CNS) symptoms, etc. Babesia infections mimic those seen with malaria,...

Laboratory Considerations

Clostridium botulinum produces three toxins, all of which can be fatal even in small doses, In addition, this stria anaerobe is difficult to isolate. The diagnosis is made by testing tissue or patient's serum in a mouse bioassay. Mice are inoculated with the specimen in combination with various antitoxins. Persons who work with the organism are given botulism toxoid vaccination so that they will be immune to the effects of the toxin. Our patient was given antitoxin against all three botulism...

Laboratory Design With Respect To Safety

Laboratory safety is discussed in depth in Chapter 4. However, a few points are worth repeating here since they pertain to laboratory design. The emergency shower and eye wash stations should be centrally located. The standard for the location of these units is the same, that is, within 10 seconds and 100 feet of each work area. Cold water is used for emergency flushing of eyes and skin because it will do the following Slow the reaction rate of the splashed chemical Constrict blood vessels and...

Laboratory Diagnosis

Specimen Collection, Transport, and Processing Clinical specimens frequently submitted to the laboratory for direct examination and culture indude blood, which has been collected in a lysis-centrifugation blood culture tube (Isolator Wampole Laboratories, Cranbury, NJ), as well as aspirates and or tissue specimens (e.g lymph node, spleen, or cutaneous biopsies). There are no special requirements for specimen collection, transport, or processing of the organisms discussed in this chapter. Refer...

Laboratory Diagnosis Of Clostridium DctcifAssociated Diarrhea

The definitive diagnosis of C. diffidle-assodated diarrhea is based on clinical criteria combined with laboratory testing. Visualization of a characteristic pseudomembrane or plaque on endoscopy is diagnostic for pseudomembranous colitis and, with the appropriate history of prior antibiotic use, meets the criteria for diagnosis of antibiotic-associated pseudomembranous colitis. No single laboratory test will establish the diagnosis unequivocally. Three tests are currently available for routine...

Laboratory diagnosis of mycobacterial infections

Specimens received by the laboratory for mycobacterial smear and culture must be handled in a safe manner. Tuberculosis ranks high among laboratory-acquired infections. Therefore, laboratory and hospital administrators must provide laboratory personnel with facilities, equipment, and supplies that will reduce this risk to a minimum All tuberculin-negative personnel should be skin-tested at least every year. Biosafety Level 2 practices, containment equipment, and facilities for preparing...

Laboratory Environment

The biohazard symbol should be prominently displayed on laboratory doors and any equipment (refrigerators, incubators, centrifuges) that contain infectious material. The air-handling system of a microbiology laboratory should move air from lower to higher risk areas, never the reverse. Ideally, the microbiology laboratory should be under negative pressure, and air should not be recirculated after passing through microbiology (see Chapter 62 for a more detailed discussion of negative pressure in...

Laboratory Methods and Strategies for chapter Antimicrobial Susceptibility Testing

As discussed in Chapter 11, most clinically important bacteria are capable of acquiring and expressing resistance to antimicrobial agents commonly used to treat the infections they cause. Therefore, once an organism is isolated in the laboratory, characterization frequently includes tests to detect antimicrobial resistance. That is to say that in addition to the organism's identification, its antimicrobial susceptibility profile is often another key component of the clinical laboratory report...

Laboratory Methods for Diagnosis chapter JO of Parasitic Infections

Entamoeba glngivalis Flagellates Trichomonas vaginalis Trichomonas tenax Coccidia and Microsporidia (Other Body Sites) Coccidia Toxoplasma gondii Microsporidia Nosema Brachiota Maforma Pleistophora Trachipleistophora Encephalitozoon Enterocytozoon Mterospondium* Helminths Nematodes (Roundworms) Intestinal Ascaris lumbricoides Enterobius vermicularis Ancylostoma duodenale Necatoramericanus Strongyloides stercoralis Trichostrongylus spp. Trichuristrichiura Capillaria philippinensis Tissue...

Laboratory Methods For Diagnosis Of Parasitic Infections

If no RBCs are seen in the cytoplasm and the trophozoites measure s. 12 jim, Entamoeba histolytica (true pathogen) cannot be differentiated from nonpathogenic Entamoeba dispar. Currently, there are immunoassays available that will confirm organisms in the Entamoeba histolytica E. dispar group in the specimen, as well as one immunoassay that will confirm the presence of the pathogen E. histolytica. 2. It is Important for the physician to recognize that a report of E. histolytica E. dispar does...

Laboratory Methods In Basic Mycology

The organism is Blastomyces dermatitidis. This organism may be rapidly and accurately identified in the specimen upon direct examination, by the experienced microscopist. The characteristic features are the moderate size and the pathognomonic broad-base bud. The calcofluor white KOH is a rapid and useful method for detecting and, in some instances, such as this one, identifying fungi in clinical specimens. 2. This organism is one of the systemic dimorphic molds. These organisms have a yeast or...

Laboratory Methods In Basic Virology

L Common viruses that cause disease this serious in young adults include influenza A and adenovirus. Other viruses that should be considered if implicated by epidemiologic investigation are the hantaviruses (e.g., sin nombre virus). 2. Sputum and upper respiratory tract secretions are excellent specimens for the detection of influenza and adenoviruses however, adenoviruses may be present in the absence of overt disease. Specimens collected by invasive techniques, such as broncho-alveolar lavage...

Laboratory Physical Design chapter Management and Organization

Microbiology laboratories operate to various venues. During the 1990s the trend changed from centralized facilities that operate from large hospital, public health, or independent laboratories to decentralized facilities that operate outside of a main laboratory but may still be within the physical hospital facility. Decentralized testing is also known as alternatesite testing. Alternate-site testing is performed in physician office laboratories (POLs), in ancillary outpatient hospital clinics,...

Laboratory Response Network

Because communication between clinical and public health laboratories is so critical in the post-2001 era, CDC created an organizational structure whereby isolates and lines of communication flow freely among members.4 The Laboratory Response Network (LRN) was originally designed as a four-tier system. Clinical (Level A) laboratories were at the bottom of a triangle, sending specimens to a Level B (local public health laboratory) or Level C (state public health laboratory) for confirmation....

Larynaotracheobronchitis

Another clinical syndrome closely related to laryngitis is acute laryngotracheobronchitis, or croup. Croup is a relatively common illness in young children, primarily those younger than 3 years of age. Of significance, croup can represent a potentially more serious disease if the infection extends downward from the larynx to involve the trachea or even the bronchi. Illness is charactenzed by variable fever, inspiratory stridor (difficulty in moving enough air through the larynx), hoarseness,...

Legionella

L The urinary antigen test effectively detects Legionella pneumophila type 1, but is less often positive in infections with the other L. pneumophila types. 2. Legionella is an opportunistic disease, meaning that there is generally an underlying factor in the host to account for the ability of the bacteria to cause infection. Risk factors include lowered immune system either from corticosteroids, malignancy, or age. Infants and the elderly naturally have a lowered immune system. Surprisingly...

Leptospira

The leptospires include both free-living and parasitic forms. Pathogenic Leptospira species are currently classified in seven species based on DNA relatedness, with Leptospira interrogans sensu stricto being the main species associated with human leptospirosis in France, this L organism is responsible for about 60 of human cases, the pathogens include about 80 serologically defined types that were formerly designated as species and are now known as serovars, or serotypes, of L. interrogans nsu...

Less Common Or Prevalence Not Established

Table 21 -2 Species Included in the Genera Rhodococcus, Gordonia, and Tsukamurella fast, branching, filamentous bacteria that can fragment into rods and cocci. The extent of acid-fastness is dependent on the amount and complexity of mycolic acids in the organism's cell envelope and on culture conditions. The differentiation of these three genera, as well as spedes identification, is difficult.3,9-12 In particular, the genus Rhodococcus consists of a very diverse group of organisms in terms of...

Limitations

This method cannot be used on fresh clinical specimens. It is for culture identification only. The use of nucleic add probes with cultures grown on a blood-containing medium is unsatisfactory for testing, in that hemin will chemilu-minesce and yield a false-positive result. first of these to be released and is the representative compound of this group. Caspofungin. Caspofungm is fungiddal against Candida spp., induding spedes that are or may be resistant to fluconazole, such as C. krusei and C....

Limitations Of Standardization

Although standardization of in vitro conditions is essential, the use of standard conditions imparts some limitations. Most notably, the laboratory test conditions in no way mimic the in vivo environment at the infection sites where the antimicrobial agent and bacteria will actually interact. Factors, such as bacterial inoculum size, pH, cation concentration, and oxygen tension (i.e., atmosphere), can differ substantially depending on the site of infection. Because of the lack of correlation...

Litial Processing

Initial processing of CSF for bacterial, fungal, or parasitic studies includes centrifugation of all specimens greater than 1 mL in volume for at least 15 minutes at 1500x g. Specimens in which cryptococci or mycobacteria are suspected must be handled differently. (Discussions of techniques for culturing CSF for mycobacteria and fungi are found in Chapters 45 and 50, respectively.) The supernatant is removed to a sterile tube, leaving approximately 0.5 mL of fluid in which to suspend the...

Lung Infections

The most common nosocomial pathogens causing pneumonia are gram-negative rods, S. aureus, and Moraxella catarrhalis. Streptococcus pneumoniae and Haemophilus influenzae, which cause the majority of community-acquired pneumonias, are not important etiologic agents in hospital-acquired infections except very early during the hospital course (first 2 to 5 days) these infections probably represent infections that were already incubating at the time of the hospital admission. The risk factors that...

Lysis Centrifugation

The lysis centrifugation system commercially available is the Isolator (Wampole Laboratories, Cranbury, NJ), The Figure 52-6 Lysis centrifugation blood culture (Isolator System, Wampole Laboratories) uses vacuum-draw collection tubes with a lysing agent and special apparatus (Isostat Press) to facilitate removal of the supernatant without use of needles. (Courtesy Wampole Laboratories, Cranbury, NJ.) Figure 52-5 Becton Dickinson Septi-Chek pediatric size bipbasic blood culture bottle. The...

M m

Figure 17-1 Chains of streptococci seen in Gram stain prepared from broth culture. Figure 17-1 Chains of streptococci seen in Gram stain prepared from broth culture. ments of the genera in this chapter are noted in Tables 17-3 and 17-4. Except for Abiotrophia and Granulicatella, the organisms discussed in this chapter will grow on standard laboratory media such as 5 sheep blood and chocolate agars. They will not grow on MacConkey agar but will grow on gram-positive selective media such as CNA...

Mac

Clinically significant Isolates from patients on prior macroiide therapy Isolates from patients who become bacteremic while on macroiide preventive therapy isolates from patients who relapse while on macroiide therapy Initial isolates from blood tissue of patients with disseminated disease or respiratory samples from patients with pulmonary disease

Mailing Biohazardous Materials

In March 2005 the requirements for packaging and shipping biologic material were significantly revised in response to the international community's desire to ensure safe and trouble-free shipment of infectious material while attempting to be more reasonable. Before this date, clinical specimens submitted for infectious disease diagnosis as well as isolates of any microotganism were considered an infectious substance and packaged and labeled under UN6.2 dangerous goods regulations. Now, only...

Materials

L CMV Brite Kit (IQ Products, The Netherlands, distributed by Biotest Diagnostic Corporation, Denville, NJ), which includes dextran solution, RBC lysing solution, fixative solution, permeabilization solution, fetal calf serum, monoclonal antibodies, and control slides. Store at 2 to 8 C 2. Sterile pipettes and micropipettes 3. Refrigerated centrifuge and 15 mL conical bottom centrifuge tubes 4. Cytocentrifuge (Shandon, Inc., Pins-burgh, Pa.) 5. Phosphate buffered saline (PBS), calcium- and...

Media Of Choice

The primary plating media for inoculating anaerobic specimens can be picked from the media listed in Table 43-4. In general they include a nonselective anaerobic blood agar and one or all of the following selective media Bacteroides bile esculin agar (BBE), laked kanamycin-vancomycin blood agar (LKV), or anaerobic phenylethyl alcohol agar (PEA). In addition, aerobic 5 sheep blood agar, chocolate agar, and MacConkey agar are set up because most anaerobic infections are polymicrobic and may...

Meningitis And Other Infections Of The Central Nervous System

This organism is most likely Neisseria meningitidis, which is oxidase-positive. To confirm the identification, numerous commercial rapid tests are available. They take advantage of the fact that this species ferments maltose and glucose but not lactose. Other members of the genus have different patterns of fermentation. Some systems rely on specific enzyme production by the organism to identify Neisseria to the species level (see Table 13-1). Because of the importance of correctly diagnosing...

Method

Using an inoculating loop, streak two or three suspect colonies of a pure culture onto a blood agar plate. ' . Using heated forceps, place a bacitracin disk in the first quadrant (area heaviest growth). Gently tap the disk to ensure adequate contact with the agar surface. 3. Incubate the plate for 18 to 24 hours at 35 C in ambient air. 4. Look for zone of inhibition around disk. zone of inhibition is positive (Streptococcus pyogenes) growth up to the disk is negative (Streptococcus algalatiae)....

Method A

Inoculate one M. hominis agar plate and two M, hominis broth tubes, one broth containing phenol red indicator and one without the possibly inhibitory phenol red, each with 0.1-mL specimen from transport media. 3. Incubate broths in tightly sealed test tubes for 5 days. If the phenol red-containing broth changes color to red A 29-year-old previously healthy female presented with a productive cough, fever to 102 F, and severe headache. She had cervical adenopathy (swollen glands), although she...

Methods

Wear latex gloves and laboratory coat when handling patient specimens. Use biological safety cabinet whenever tube containing specimen is open. Use biocontainment safety covers during centrifugation procedures. 2. Leukocyte isolation from peripheral blood a. Allow kit reagents to come to room temperature (20 to 25 C). b. Mix 5 to 7 mL of anticoagulated blood with 1.5 mL of dextran reagent (reagent A) in a 15-mL conical centrifuge tube. If a greater volume of blood is used, the dextran-to-blood...

Methods and Strategies

Rationale for a method of organism identification_ Deciding how to teach microbiology in a manner that is both comprehensive and yet understandable is difficult. Most microbiology text chapters are organized by genus name and provide no obvious approach as to how to work up a clinical isolate. Some texts have flowcharts containing algorithms for organism workup many of these, however, are either too broad to be helpful (e.g., gram-positive vs. gramnegative bacilli) or too esoteric (e.g.,...

Methods Of Disinfection

The three physical methods of disinfection are Boiling at 100 C for 15 minutes, which kills vegetative bacteria Pasteurizing at 63 C for 30 minutes or 72 C for 15 seconds, which kills food pathogens Using nonionizing radiation such as ultraviolet (UV) light UV rays are long wavelength and low energy. They do not penetrate well and organisms must have direct surface exposure, such as the working surface of a BSC, for this form of disinfection to work. ' Chemical disinfectants comprise many...

Methods That Directly Measure Antimicrobial Activity

Methods that directly measure antimicrobial activity involve bringing the antimicrobial agents of interest and the infecting bacterium together in the same in vitro environment to determine the impact of the drug's presence on bacterial growth or viability. The level of impact on bacterial growth is measured and interpreted so that the organism's resistance or susceptibility to each agent tested can be reported to the clinician. Direct measures of antimicrobial activity are accomplished using...

Methoo

Suspend a very small inoculum of yeast cells obtained from an isolated colony in 0.5 mL of sheep serum (or rabbit plasma). 2. incubate the tubes at 35 to 37 C for no longer than 3 hours. 3. After incubation, remove a drop of the suspension and place on a microscope slide. Examine under low-power magnification for the presence of germ tubes. A germ tube is defined as an appendage that is half the width and 3 to 4 times the length of the yeast cell from which it arises (see Figure 50-2). There is...

Microbiology Laboratory

The issue of laboratory quality has evolved over more than three decades since the first recommendations for quality control (QC) were published in 1965. Just as microbial taxonomy has changed over the years, the approach to quality has evolved as well. QC is now seen as only one part of a total laboratory quality program. Quality now also includes total quality management (TQM), continuous quality improvement (CQI) or performance improvement (PI), and quality assurance (QA). TQM, CQI, and PI...

Microorganism Colonization Of Host Surfaces

Once a microbe and the human host are brought into contact, the outcome of the encounter depends on what happens during each step of interaction (see Figure 3-1), beginning with colonization. The human host's role in microbial colonization, defined as the persistent survival of microorganisms on a surface of the human body, is dictated by the defenses that protect vital internal tissues and organs against microbial invasion. The first defenses are the external and internal body surfaces that...

Minus

S. moniliformis is susceptible to SPS, the anticoagulant used in blood culture bottles. By adding more blood, all of the SPS would be bound up, and the inhibitory effect of the anticoagulant will be minimized. This was successful and the organisms grew. The effort to grow it from the tube failed because there was too much SPS in the tube used to draw the blood. 2. S. moniliformis will not grow on laboratory media unless there is sufficient blood, ascitic fluid, or horse serum in the medium....

Miscellaneous

Unusual agents and those that have not been cultured, such as the mycobacteria that may be associated with Crohn's disease and the bacterium associated with Whipple's disease, identified by molecular methods as a new agent, Trophyrema whipplei, are also candidates as etiologic agents of GI disease. Occasionally, stool cultures from patients with diarrheal disease yield heavy growth of organisms such as enterococci, Pseudomonas spp., or Table 59-4 General Characteristics of the Common Agents of...

Miscellaneous Infections

Infections of the male prostate, epididymis, and testes are usually bacterial. In younger men, chlamydiae predominate as the cause of epididymitis and possibly of prostatitis. Urine or discharge collected via the urethra is the specimen of choice unless an abscess* is drained surgically or by needle and syringe. The first few milliliters of voided urine may be collected before and after prostatic massage to try to pinpoint the anatomic site of the infection. Cultures are inoculated to support...

Miscellaneous Matters

Blood drawn for culture must not be allowed to clot. If bacteria become entrapped within a clot, their presence may go undetected. Thus, blood drawn for culture may be either inoculated directly into the blood culture broth media or into a sterile blood collection tube containing an anticoagulant for transport to the laboratory for subsequent inoculation. Heparin, ethylenediaminetetraacetic acid (BDTA), and citrate inhibit numerous organisms and are nor recommended for use....

Miscellaneous Specimen Types

Other specimens that may be obtained for diagnosis of GI tract infection include duodenal aspirates (usually for detection of Giardia or Strongyloides), which should be examined immediately by direct microscopy for the presence of motile protozoan trophozoites, cultured for bacteria, and placed into polyvinyl alcohol (PVA) fixative for subsequent parasitic examination. The laboratory should be informed in advance that such a specimen is going to be collected so that the specimen can be...

Mm

Recommended therapy includes ceftriaxone or quinolones (e.g., ciprofloxacin, ofloxacin, levofloxacin). Macrolides also may be used Penicillin resistance by beta-lactamase production is common. Resistance to quinolones Is emerging As documented in Chapter 12 disk diffusion, agar dilution, limited commercial methods Testing by disk diffusion may not detect decrease in quinolone activity. No ceftriaxone resistance has been documented Supportive therapy for shock and antimicrobial therapy using...

Molecular Biological Techniques

The development of amplification techniques has led to numerous publications for the direct detection of many enteric pathogens, including all major organism groups bacteria, viruses, and parasites. Probes for Salmonella Shigella, EHEC, and Yersinia are being evaluated. A disadvantage with probe technology is that the organism itself is not available for susceptibility testing, which is important for certain bacterial pathogens (e.g., Shigella) for which susceptibility patterns vary.

Molecular Identification

The genus Mycobacterium consists of a diverse group of acid-fast bacilli. As previously mentioned, conventional methods for identification of these organisms are well established and inexpensive, but these methods are time-consuming and labor-intensive, and they provide inconclusive results, often leading to species identifications based on a best-fit approach. The introduction of molecular methods has revolutionized the identification of mycobacteria by reducing time to identification as well...

Monoclonal Antibodies

The ability to create an immortal cell line producing large quantities of a completely characterized and highly specific antibody, known as a monoclonal antibody, has revolutionized immunologic testing. Monoclonal antibodies are produced by the offspring (clones) of a single hybrid cell, the product of fusion of an antibody-producing plasma B cell and a malignant antibody-producing myeloma cell. One technique for the production of such a clone of cells, called hybridoma cells, is illustrated in...

Mrect detection methods

Other than Gram stain of patient specimens, there are 10 specific procedures for the direct detection of these organisms in clinical material. Acinetobacter spp. are plump coccobacilli that tend to resist alcohol decolo-rization they may be mistaken for Neisseria spp. The Bordetella spp. are coccobacilli or short rods. S. malto-philia, P. oryzihabitans, and P. luteola are short to medium-size straight rods. CDC group NO-1 are coccoid to medium-size bacilli. Table 23-3 Colonial Appearance and...

Mucous Membrane Protective Activity Structures

Mucosal cells Rapid sloughing for bacterial removal Tight intercellular junctions prevent bacterial penetration Goblet cells Mucus production Protective lubrication of cells Bacterial trapping Contains specific antibodies with specific activity against bacteria Provision of antibacterial substances to mucosal surface Lysozyme degrades bacterial cell wall iron supply Lactoperoxidase production of substances toxic to bacteria Mucosa-associated Mediates specific responses against lymphoid tissue...

Mycoplasma Hominis

Mycoplasma hominis can be recovered during postabortal or postpartum fever, following gynecologic or urologic procedures, or in patients who were immunocompromised.7-10-13 Isolates can be recovered from both non- automated and automated blood culture systems. However, because so few clinical isolates have been recovered to date, it has not been determined which blood culture system is optimal for recovering M. hominis. Although some studies report that M. hominis can produce sufficient C02 to...

Myositis

Myositis (involvement of muscle) is caused by various infectious agents. The nature of the pathologic process is variable, sometimes involving extensive necrosis of muscle, as in gas gangrene or clostridial myonecrosis, necrotizing cutaneous myositis or synergistic nondostridial anaerobic myonecrosis, anaerobic streptococcal myonecrosis, myonecrosis caused by Bacillus spp., or myonecrosis caused by Aeromonas. Focal collections of suppuration in musde (staphylococcal or other pyo-myositis...

Nd

U to data v, variable +, > 90 of strains positive (+), > 90 of strains positive but reai quire a drop of rabbit serum on the slant or a heavy inoculum, fj ay require the addition of 1 to 2 drops rabbit serum per 3 mL of fermentation broth to st Pirate is usually reduced to gas. delayed (i.e., 2 to 7 days) -, > 90 of

Neck

Infections of the deep spaces of the neck are potentially serious because they may spread to critical structures such as major vessels of the neck or to the mediastinum leading to mediastinitis, purulent pericarditis, and pleural empyema. The oral flora are responsible for these infections. Accordingly the predominant organisms are anaerobes, primarily Peptostreptococcus, various Bacleroides, Prevotella, Porphyromonas, Fusobacterium spp,( and Actinomyces. Streptococci, chiefly of the viridans...

Necrotizing Fasciitis

Necrotizing fasciitis is a serious infection that occurs relatively infrequently. The basic pathology is infection of the fascia overlying muscle groups, often with involvement of the overlying soft tissue. At the fascial level, no barrier exists to spread of infection, so fas ciitis may extend widely and rapidly to involve huge areas of the body in short periods. This process, once known as hospital gangrene, typically involves group A streptococci or S. aureus. Necrotizing fasciitis also...

New test SEJo95x i 0

95 CONFIDENCE INTERVAL Currant Test 0.90 - (1.96 x 0.05) to 0.90 + (1.96 x 0.05) 0.90-0.10 to 0.90 + 0.10 0.80 to 1.00 The new test would be acceptable (validated) at the 95 CI. 0.95 - (1.96 x 0.04) to 0.35 + (t.96 x 0.04) 0.95 - 0.08 to 0.95+ 0.08 0.87 to 1.03 standard error (SE) and sensitivity of the tests must be known (Box 62-2). The standard error can be calculated using the following formula where p sensitivity of the test where n sample size where J square root The example in Box 62-2...

Nontuberculous Mycobacteria

In general, treatment of patients with diseases caused by NTM require more individualization of therapy than patients with tuberculosis. This individualization is based on the species of mycobacteria recovered, site and severity of infection, antimicrobial drug susceptibility results, concurrent diseases, and the patient's general condition.9 Currently, sufficient data exist to base general recommendations for susceptibility testing of MAC, M. kansasii, and M. marinum.1 1 In addition,...

Normally Sterile Body Fluids Bone And Bone Marrow And Solid Tissues

This organism likely is Peptostreptococcus spp., because it did not grow aerobically. This genus has been subdivided into a number of new genera. However, most laboratories use the general genus name Peptostreptococcus spp., because it is not clinically important to separate the anaerobic gram-positive cocci further. 2. The patient is likely infected with her own skin flora, which was introduced at the time of the surgery. Because of the placement of a foreign object, her body was unable to...

Note

If you are currently using one of the stool fixatives that contains a mercuric chloride substitute (e.g., zinc sulfate), remember that the proficiency testing specimens you receive for permanent staining may have been preserved in PVA using the mercuric chloride fixative base. If you use the trichrome staining method for your mercuric chloride sub , stitute fixatives, you may have eliminated the 70 alcohol iodine step and the following 70 alcohol rinse steps fro your method. However, when you...

Nt

Data compiled tram references 13.16,18-20,32,33,36,38 and 42 Cytochrome enzymes as delected by the porphyrin broth test SEIZES 8 PSe 0CatalaSeeH9rvescence' ** when strains grown on a blood-containing medium are tested for catalase production. Vagococcus fluviahs is negative for l-arablnose and rafflnose, but the motile Enterococcus galllnarum Is positive fw both The most common isolates are positive. 'S. pyogenes, S. pneumoniae, and S. urinalis are PYR positive. 5 to 10 of viridans streptococci...

Nucleic Acid Amplification

Molecular techniques, such as conventional and realtime PCR, have been used to detect M. tuberculosis directly in clinical specimens two kits are available commercially that are approved by the FDA. The Amplicor Mycobacterium tuberculosis test (Roche Diagnostic Systems, Branchburg, NJ) uses PCR to detect M. tuberculosis directly in respiratory specimens the Amplified Mycobacterium tuberculosis Direct Test (Gen-Probe, San Diego, Calif) is based on ribosomal RNA amplification. The Roche assay...

Nucleic Acid Hybridization Methods

Hybridization methods are based on the ability of two nucleic acid strands that have complementary base sequences (i.e are homologous) to specifically bond with each other and form a double-stranded molecule, or duplex or hybrid. This duplex formation is driven by the consistent manner in which the base adenine always bonds to thymine, while the bases guanine and cytosine always form a bonding pair (see Figure 2-2). Because hybridization requires nucleic acid sequence homology, a positive...