Detection of CTX-M-15 beta-lactamases in Enterobacteriaceae causing hospital- and community-acquired urinary tract infections as early as 2004, in Dar es Salaam, Tanzania

Joel Manyahi, Sabrina J. Moyo, Marit Gjerde Tellevik, Faustine Ndugulile, Willy Urassa, Bjørn Blomberg, Nina Langeland

The spread of Extended Spectrum β-lactamases (ESBLs) among Enterobacteriaceae and other Gram-Negative pathogens in the community and hospitals represents a major challenge to combat infections. We conducted a study to assess the prevalence and genetic makeup of ESBL-type resistance in bacterial isolates causing community- and hospital-acquired urinary tract infections. A total of 172 isolates of Enterobacteriaceae were collected in Dar es Salaam, Tanzania, from patients who met criteria of community and hospital-acquired urinary tract infections. We used E-test ESBL strips to test for ESBL-phenotype and PCR and sequencing for detection of ESBL genes. Overall 23.8% (41/172) of all isolates were ESBL-producers. ESBL-producers were more frequently isolated from hospital-acquired infections (32%, 27/84 than from community-acquired infections (16%, 14/88, p < 0.05). ESBL-producers showed high rate of resistance to ciprofloxacin (85.5%), doxycycline (90.2%), gentamicin (80.5%), nalidixic acid (84.5%), and trimethoprim-sulfamethoxazole (85.4%). Furthermore, 95% of ESBL-producers were multi-drug resistant compared to 69% of non-ESBL-producers (p < 0.05). The distribution of ESBL genes were as follows: 29/32 (90.6%) bla CTX-M-15, two bla SHV-12, and one had both bla CTX-M-15 and bla SHV-12. Of 29 isolates carrying bla CTX-M-15, 69% (20/29) and 31% (9/29) were hospital and community, respectively. Bla SHV-12 genotypes were only detected in hospital-acquired infections. bla CTX-M-15 is a predominant gene conferring ESBL-production in Enterobacteriaceae causing both hospital- and community-acquired infections in Tanzania.