title: Detection of new SHV-12, SHV-5 and SHV-2a variants of extended spectrum beta-lactamase in Klebsiella pneumoniae in Egypt.
abstract: BACKGROUND
  Klebsiella pneumoniae outbreaks possessing extended-spectrum β-lactamase- (ESBL) mediated resistance to third-generation cephalosporins have increased significantly in hospital and community settings worldwide. The study objective was to characterize prevalent genetic determinants of TEM, SHV and CTX-M types ESBL activity in K. pneumoniae isolates from Egypt.
  
  
  METHODS
  Sixty five ESBL-producing K. pneumoniae strains, isolated from nosocomial and community-acquired infections from 10 Egyptian University hospitals (2000-2003), were confirmed with double disc-synergy method and E-test. blaTEM, blaSHV and blaCTX-m genes were identified by PCR and DNA sequencing. Pulsed-field gel electrophoresis (PFGE) was conducted for genotyping.
  
  
  RESULTS
  All isolates displayed ceftazidime and cefotaxime resistance. blaTEM and blaSHV genes were detected in 98% of the isolates' genomes, while 11% carried blaCTX-m. DNA sequencing revealed plasmid-borne SHV-12,-5,-2a (17%), CTX-m-15 (11%), and TEM-1 (10%) prevalence. Among SHV-12 (n=8), one isolate displayed 100% blaSHV-12 amino acid identity, while others had various point mutations: T17G (Leu to Arg, position 6 of the enzyme: n=2); A8T and A10G (Tyr and Ile to Phe and Val, positions 3 and 4, respectively: n=4), and; A703G (Lys to Glu 235: n=1). SHV-5 and SHV-2a variants were identified in three isolates: T17G (n=1); A703G and G705A (Ser and Lys to Gly and Glu: n=1); multiple mutations at A8T, A10G, T17G, A703G and G705A (n=1). Remarkably, 57% of community-acquired isolates carried CTX-m-15. PFGE demonstrated four distinct genetic clusters, grouping strains of different genetic backgrounds.
  
  
  CONCLUSIONS
  This is the first study demonstrating the occurrence of SHV-12, SHV-5 and SHV-2a variants in Egypt, indicating the spread of class A ESBL in K. pneumoniae through different mechanisms.
authors.affiliation: Global Disease Detection and Response Program, U,S, Naval Medical Research Unit No, 3 (NAMRU-3), Abbassia, Cairo, Egypt. enasnewire@hotmail.com
authors.forename: Enas A
authors.initials: EA
authors.lastname: Newire
authors.forename: Salwa F
authors.initials: SF
authors.lastname: Ahmed
authors.forename: Brent
authors.initials: B
authors.lastname: House
authors.forename: Esmeralda
authors.initials: E
authors.lastname: Valiente
authors.forename: Guillermo
authors.initials: G
authors.lastname: Pimentel
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D017714:Community-Acquired Infections / Q000382:microbiology; D003428:Cross Infection / Q000382:microbiology; D004269:DNA, Bacterial / Q000032:analysis; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004534:Egypt / Q000453:epidemiology; D014644:Genetic Variation; D006801:Humans; D007710:Klebsiella Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; C473109:beta-lactamase CTX-M-15; C107198:beta-lactamase SHV-12; C490029:beta-lactamase SHV-2a; C117193:beta-lactamase SHV-5; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1