Mixed Infections Involving Anaerobic BLPB

Anaerobic BLPB can be isolated from a variety of infections in adults and children, sometimes as the only isolates and sometimes mixed with other flora (Table 3). Table 4 summarizes our experience in the recovery of these organisms from skin and soft tissue infections (157-166), upper respiratory tract (167-179), lower respiratory tract (180-183), obstetric and gynecologic (184), intra-abdominal (184-186), and miscellaneous infections (187-190).

The rate of isolation of these organisms varies in each infection entity (Table 4) (156). BLPB were present in 288 (44%) of 648 patients with skin and soft tissue infections, 75% harbored aerobic and 36% had anaerobic BLPB. The infections in which BLPB were most frequently recovered were vulvovaginal abscesses (80% of patients), perirectal and buttock abscesses (79%), decubitus ulcers (64%), human bites (61%) and abscesses of the neck (58%). The predominant BLPB were Staphylococcus aureus (68% of patients with BLPB) and the B. fragilis group (26%).

BLPB were found in 262 (51%) of 514 patients with upper respiratory tract infections 72% URTI had aerobic BLPB and 57% had anaerobic. The infections in which these organisms were most frequently recovered were adenoiditis (83% of patients), tonsillitis in adults (82%) and children (74%), and retropharyngeal abscess (71%). The predominant BLPB were S. aureus (49% of patients with BLPB), pigmented Prevotella and Porphyromonas (28%) and the B. fragilis group (20%).

BLPB were isolated in 81 (59%) of 137 patients with pulmonary infections; 75% had aerobic BLPB, and 53% had anaerobic BLPB. The largest number of patients with BLPB was found in patients with cystic fibrosis (83% of patients), followed by pneumonia in intubated patients (78%) and lung abscesses (70%). The predominant BLPB was B. fragilis group (36% of patients with BLPB), S. aureus (35%), pigmented Prevotella and Porphyromonas spp. (16%), Pseudomonas aeruginosa (14%), Klebsiella pneumoniae (11%) and E. coli (10%).

BLPB were recovered in 104 (92%) of 113 patients with surgical infections; 5% of the patients had aerobic BLPB and 98% had anaerobic BLPB (Table 4). The most predominant BLPB was the B. fragilis group (98% of patients with BLPB).

BLPB were recovered in 16 (28%) of 57 patients with miscellaneous infections, which included periapical and intracranial abscesses and anaerobic osteomyelitis; 25% had aerobic

TABLE 3 Infections Involving Beta-Lactamase-Producing Bacteria (BLPB)


Predominant BLPB

Respiratory tract Acute sinusitis and otitis Chronic sinusitis and otitis Tonsillitis

Bronchitis, pneumonia

Aspiration pneumonia, lung abscesses

Skin and soft tissue Abscesses, wounds, and burns in the oral areas, paronychia, bites Abscesses, wounds, and burns in the rectal area

Abscesses, wounds, and burns in the trunk and extremities

Obstetric and gynecologic Vaginitis, endometritis, salpingitis, pelvic inflammatory disease

Intra-abdominal Peritonitis, chronic cholangitis, abscesses

Miscellaneous Periapical and dental abscesses Intracranial abscesses Osteomyelitis

Haemophilus influenzae, Moraxella catarrhalis Staphylococcus aureus, anaerobic gram-negative bacilli S. aureus, anaerobic gram-negative bacilli H. influenzae, M. catarrhalis, Legionella pneumophila S. aureus, anaerobic gram-negative bacilli, Enterobacteriaceae

S. aureus, pigmented Prevotella and Porphyromonas

Escherichia coli, Bacteroides fragilis group, Pseudomonas aeruginosa S. aureus, P. aeruginosa

Neisseria gonorrhoeae, E. coli, Prevotella spp.

E. coli, B. fragilis group

Pigmented Prevotella and Porphyromonas S. aureus, anaerobic gram-negative bacilli S. aureus, anaerobic gram-negative bacilli

Anaerobic gram-negative bacilli = Bacteroides, Prevotella, and Porphyromonas.

BLPB and 80% had anaerobic BLPB. The rate of recovery of BLPB was not significantly different in these infections. The most frequently recovered BLPB were pigmented Prevotella and Porphyromonas spp. (37% of patients with BLPB), S. aureus and B. fragilis groups (25% each).

Pelvic inflammatory disease (PID) is a polymicrobial infection (191-193) involving in most cases numerous isolates, including Neisseria gonorrhoeae, Chlamydia trachomatis, Enterobacteriaceae, and AGNB (B. fragilis, P. bivia, and P. disiens). All of the above organisms (except for C. trachomatis) are capable of producing BL. In a summary of 36 studies published from 1973 to 1985, Eschenbach found BLPB in 1483 (22%) of 6637 specimens obtained from obstetric and gynecologic infections (191). The predominant BLPB were Enterobacteriaceae, S. aureus, B. fragilis group and pigmented Prevotella and Porphyromonas spp. The increase in the failure rate of penicillin in eradicating these infections is an indirect proof of their importance (192-194).

We have recovered 2052 isolates from 736 patients with obstetrical and gynecological infections (194). Of these isolates, 355 (17%) were BLPB, 211 (59%) were anaerobes, and 144 (41%) were aerobes and facultatives. These BLPB were recovered from 276 (37%) of all 736 patients. The most frequently recovered BLPB were AGNB. Among them B. fragilis group accounted for 129 (36%) of all 355 BLPB. Ninety-nine percent of B. fragilis group were BLPB. Others were P. bivia (49 of 151 isolates, or 32%, were BLPB), P. disiens (6 of 17, or 35%), and Prevotella melaninogenica (23 of 110, or 21%). S. aureus was the second most common BLPB isolated in 21% of patients.

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