Production of beta-lactamase in Trinidad: An association with multiple resistance to beta-lactam antibiotics

Over a 11-month period, 1,572 bacterial isolates were collected from patients with community-acquired infections. Isolated pathogens included Escherichia coli (476/1,572), Klebsiella species (308/1,572), Staphylococcus aureus (188/1,572), Pseudomonas spp. (156/1,572), Proteus spp. (100/1,572), Enterobacter spp. (96/1,572), Neisseria gonorrhoeae (88/1,572), Staphylococcus epidermis (80/1,572) and Enterococcus faecalis, Acinetobacter spp., Citrobacter spp., Haemophilus infuenzae Haemophilus ducreyi and Providencia spp., each of which were less than 30/1,572. Beta-lactamase presence was measured by a chromogenic method. Beta-lactamase was found in more than 90% of urinary pathogens, including 94.8% of E. coli, 95.8% of Enterobacter spp., 88.5% of Proteus spp. and 81.7% of Klebsiella spp. Only 73.0% of S. aureus were beta-lactamase positive. Beta-lactamase presence was associated with bacterial resistance to penicillin G, ampicillin and amoxicillin, but not with cefuroxime, whose sensitivity remained high. Our results show a high prevalence of beta-lactamase in Trinidad, suggesting a need for a national antibiotic prescribing policy and monitoring system, and the replacement of relatively ineffective penicillins with newer agents such as cefuroxime.