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

BMC Infect Dis. 2017 Apr 17;17(1):282. doi: 10.1186/s12879-017-2395-8.


Background: 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.

Methods: 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.

Results: 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.

Conclusion: bla CTX-M-15 is a predominant gene conferring ESBL-production in Enterobacteriaceae causing both hospital- and community-acquired infections in Tanzania.

Keywords: ESBL; Tanzania; Urinary tract infections.

MeSH terms

  • Bacterial Typing Techniques / methods*
  • Community-Acquired Infections / drug therapy
  • Community-Acquired Infections / epidemiology*
  • Community-Acquired Infections / microbiology*
  • Cross Infection / epidemiology
  • Cross Infection / microbiology
  • Drug Resistance, Bacterial / genetics
  • Drug Resistance, Multiple / genetics
  • Enterobacteriaceae / genetics*
  • Enterobacteriaceae / isolation & purification
  • Enterobacteriaceae Infections / drug therapy
  • Enterobacteriaceae Infections / epidemiology*
  • Enterobacteriaceae Infections / microbiology
  • Female
  • Hospitals
  • Humans
  • Microbial Sensitivity Tests
  • Polymerase Chain Reaction
  • Tanzania / epidemiology
  • Trimethoprim, Sulfamethoxazole Drug Combination / therapeutic use
  • Urinary Tract Infections / drug therapy
  • Urinary Tract Infections / epidemiology*
  • Urinary Tract Infections / microbiology*
  • beta-Lactamases / analysis
  • beta-Lactamases / genetics*


  • Trimethoprim, Sulfamethoxazole Drug Combination
  • beta-lactamase CTX-M-15
  • beta-Lactamases