title: Prevalence and Genotypic Characterization of Extended-Spectrum Beta-Lactamases Produced by Gram Negative Bacilli at a Tertiary Care Hospital in Rural South Western Uganda.
abstract: OBJECTIVE
  To determine the prevalence and genotypic characterisation of extended spectrum beta-lactamases produced by gram negative bacilli isolated at Mbarara Regional Referral Hospital (MRRH).
  
  
  METHODS
  Gram negative clinical isolates.
  
  
  METHODS
  Laboratory-based descriptive cross-sectional study.
  MRRH, June and August 2012.
  
  
  METHODS
  Gram negative clinical isolates were sub cultured, and identified using biochemical tests. They were screened for ESBL by using oxyimino-cephalosporins and confirmed by double disc synergy Genotyping was performed using the PCR for TEM, SHV and CTX-M. Susceptibility pattern for the extended spectrum beta-lactamases, (ESBL) - positive isolates to other antibiotic classes was performed by the Kirby Bauer Technique.
  
  
  RESULTS
  A total of 484 isolates were included in the study. The commonest ESBL producers wereEscherichia coli(34%), followed by unidentifiedcoliforms(19.3%)and Klebsiellaspp. (12.7%). Phenotypically, 88/484 were ESBL producers while genotypically 213/ 484 possessed ESBL genes. The ESBL genes wereblaCTX-M(146; 70%),blaSHV(72; 34%) andblaTEM(100; 47%). 87of 213 isolates expressed more than one ESBL gene. Of these 36 (7.4%) producedblaCTX-M/blaSHV,28 (5.8%)blaCTX-M /blaTEM, 4 (0.8%)blaSHV/blaTEM and 19 (3.9%)blaCTX-M/blaSHV/blaTEM. Sixty two (16%) were phenotypically and genotypically positive, 12 (3%) of the isolates were phenotypically positive but genotypically negative and 140 (37%) isolates were phenotypically negative but genotypically positive. The ESBL producers were highly susceptible to imipenem (95%), nitrofurantoin (66%) but less susceptible to ampicillin (4%) and ticarcillin (7%).
  
  
  CONCLUSIONS
  ESBL production among the Gram-negative clinical isolates at MRRH is very high with several isolates possessing multiple genes. The ESBL producers are highly susceptible to imipenem, but very resistant to ciprofloxacin.
authors.affiliation: Department of Microbiology, Mbarara University of Science and Technology, Mbarara, Uganda.
authors.forename: Acaku
authors.initials: A
authors.lastname: Moses
authors.affiliation: Department of Medical Microbiology, Makerere University College of Health sciences, Uganda ; MBN Clinical Laboratories Kampala, Uganda.
authors.forename: Freddie
authors.initials: F
authors.lastname: Bwanga
authors.affiliation: Epicenter Mbarara Research Base, Mbarara, Uganda.
authors.forename: Yap
authors.initials: Y
authors.lastname: Boum
authors.affiliation: Department of Microbiology, Mbarara University of Science and Technology, Mbarara, Uganda.
authors.forename: Joel
authors.initials: J
authors.lastname: Bazira
keywords: Antibiotics; ESBL; Uganda; resistance patterns; sensitivity patterns