title: Sequence analysis of genes mediating extended-spectrum beta-lactamase (ESBL) production in isolates of Enterobacteriaceae in a Lagos Teaching Hospital, Nigeria.
abstract: BACKGROUND
  Extended-spectrum β-lactamases (ESBLs) in Gram-negative organisms is now a major concern in Enterobacteriaceae worldwide. This study determined a point-prevalence and genetic profiles of ESBL-producing isolates among members of the family Enterobacteriaceae in Lagos State University Teaching Hospital Ikeja, Nigeria.
  
  
  METHODS
  Consecutive non-repetitive invasive multidrug-resistant isolates of the family Enterobacteriaceae obtained over a period of 1 month (October 2011) were studied. The isolates were identified using VITEK-2/VITEK MS Systems. Susceptibility testing was performed using E test technique; results were interpreted according to the criteria recommended by the Clinical and Laboratory Standards Institute (CLSI, 2012). ESBL production was detected by E test ESBL method and confirmed by polymerase chain reaction (PCR).
  
  
  RESULTS
  During the one-month study period, 38 isolates with ESBL phenotypic characteristics were identified and confirmed by PCR. Of these, 21 (55.3 %) were E. coli, 12 (31.6 %) K. pneumoniae, 3 (7.9 %) Proteus spp., 1 (2.6 %) each M. morganii and C. freundii. Thirty (79 %) harbored bla CTX-M genes. Sequence analysis revealed that they were all bla CTX-M-15 genes. Twenty-nine (96.7 %) of these, also harbored bla TEM genes simultaneously. All the CTX-M-15-producing isolates carried insertion sequence bla ISEcP1 upstream of bla CTX-M-15 genes. The E. coli isolates were genetically heterogeneous, while the K. pneumoniae had 98 % homology.
  
  
  CONCLUSIONS
  Our point-prevalence surveillance study revealed a high prevalence of Enterobacteriaceae isolates harboring bla CTX-M-15 in the Hospital. Urgent implementation of antibiotic stewardship and other preventive strategies are necessary at this time in our hospital.
authors.affiliation: Department of Medical Microbiology and Parasitology, Lagos State University College of Medicine/Lagos State University Teaching Hospital, Ikeja, Nigeria. adeola68@gmail.com.|Microbiology Laboratory, BT Health and Diagnostic Centre, Lagos State University Teaching Hospital, Ikeja, Nigeria. adeola68@gmail.com.
authors.forename: Muhabat Adeola
authors.initials: MA
authors.lastname: Raji
authors.affiliation: Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait. wjamal@hsc.edu.kw.
authors.forename: Wafaa
authors.initials: W
authors.lastname: Jamal
authors.affiliation: Microbiology Laboratory, BT Health and Diagnostic Centre, Lagos State University Teaching Hospital, Ikeja, Nigeria. ojemhen@gmail.com.
authors.forename: Omoh
authors.initials: O
authors.lastname: Ojemeh
authors.affiliation: Department of Microbiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait. vincent@hsc.edu.kw.
authors.forename: Vincent Olubunmi
authors.initials: VO
authors.lastname: Rotimi
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004269:DNA, Bacterial / Q000032:analysis; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology; D006784:Hospitals, Teaching; D006801:Humans; D008826:Microbial Sensitivity Tests; D009549:Nigeria / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D001618:beta-Lactamases