BL in Clinical Infections

Several studies demonstrate the activity of the enzyme BL produced by anaerobic bacteria in polymicrobial infections. De Louvois and Hurley (206) demonstrated degradation of penicillin, ampicillin, and cephaloridine by purulent exudates obtained from 4 of 22 patients with abscesses. Studies by Masuda and Tomioka (207) demonstrated BL activity in empyema fluid. Most infections were polymicrobial and involved both K. pneumoniae and P. aeruginosa.

The presence of the enzyme BL in clinical specimens was also reported. Bryant et al.(208) detected enzyme activity in 4 of 11 pus specimen obtained from 12 patients with polymicrobial intra-abdominal abscess or polymicrobial empyema.

Brook measured BL activity in 40 (55%) of 109 abscesses (184). One hundred BLPB were recovered in 88 (77%) specimens. These included all 28 isolates of B. fragilis group, 18 of 30 pigmented Prevotella and Porphyromonas spp., 42 of 43 S. aureus, and 11 of 14 E. coli.

BL activity was detected in 46 of 88 (55%) ear aspirates that contained BLPB (184). Brook et al. found BL activity in ear aspirates of 30 of 38 (79%) children with chronic otitis media (209), in 17 of 19 (89%) ear aspirates of children with acute otitis media who failed amoxicillin (AMX) therapy (210), and in 12 sinus aspirates (three acute and nine chronic infection) of the 14 aspirates that contained BLPB. The predominant BLPBs in acute sinusitis were H. influenzae, and Moraxella catarrhalis; those in chronic sinusitis were S. aureus, Prevotella spp., Fusobacterium spp., and B. fragilis (see Table 5, chapter 14) (211).

A study investigated the monthly changes in the rate of recovery of aerobic and anaerobic penicillin-resistant bacteria in the oropharynx of children (212). Each month over a period of two years, 30 children who presented with URTI were studied. The highest number of aerobic and anaerobic BLPB and number of patients with BLPB was in April (about 60% of patients) and the lowest was in September (11-13%). A gradual increase of BLPB and penicillin-resistant Streptococcus pneumoniae occurred from September to April, and a slow decline took place from April to August. These changes correlated directly with the intake of beta-lactam antibiotics. The crowding and the increase use of antibiotics that are more common in the winter might have also contributed to the spread of BLPB. Monitoring the local seasonal variation in the rate of BLPB may be helpful in the empiric choice of antimicrobials. Judicious use of antimicrobials may control the increase of BLPB.

0 0

Post a comment