Bacteriology and beta-lactamase activity in acute exacerbation of chronic bronchitis

To assess the bacteriology of beta-lactamase (BL) enzyme activity in sputum of 40 patients with acute exacerbation of chronic bronchitis (AECB).

The microbiology, BL production by the different isolates, and BL contents in the sputum were determined.

Eighty-four isolates were recovered (2.1 isolates per specimen), 44 aerobic and facultative (1.1 isolates per specimen), and 40 anaerobic (1.0 isolate per specimen). Aerobic bacteria were recovered in only 9 (22.5%) specimens, anaerobic bacteria in 9 (22.5%), and mixed aerobic and anaerobic bacteria were found in 22 (55%). The predominant aerobic isolates were Streptococcus pneumoniae (15 isolates), Haemophilus influenzae (11), Moraxella catarrhalis and Klebsiella pneumoniae (4 each). The predominant anaerobes were Peptostreptococcus sp. (19), Prevotella sp. (11), and Fusobacterium sp.(6). Mixed flora were present in 25 (62.5%) specimens, and the number of isolates varied from 2 to 5 per specimen. Thirty-nine beta-lactamase-producing bacteria (BLPB) were isolated in 33 (82.5%) of the 40 cases. The predominant aerobic BLPB were H. influenzae, M. catarrhalis, K. pneumoniae, Staphylococcus aureus, and Escherichia coli. The predominant anaerobic BLPB were Prevotella sp. and Fusobacterium sp. Beta-lactamase activity was detected in 26 (79%) of 33 of specimens in which BLPB were isolated, and in none of the seven specimens that did not harbor BLPB.

The rapid detection of BL activity in sputum specimens may have implications for the antimicrobial management with AECB.