title: Emergence of CTX-M Group 1-ESBL producing Klebsiella pneumonia from a tertiary care centre in Karachi, Pakistan.
abstract: BACKGROUND
  Extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae have been reported previously from Pakistan but the genotypic characteristics of these enzymes is not known. Hence the aim of the study was first to characterise the genotypic content of these beta-lactamases and secondly to assess the clonal relationship of these isolates.
  
  
  METHODS
  We analysed 65 non-duplicate ESBL positive, K. pneumoniae isolates prospectively collected based on phenotype as detected using the two-disc method. Isolates were collected from different sources: blood cultures (46.15%; n = 30); tracheal aspirates (24.6%; n = 16); urine (10.7%; n = 7); wound swabs, pus and tissue (18.4%; n = 12). ESBL production was confirmed by the ESBL E-test method and the presence of the blaCTX-M encoding genes was confirmed by polymerase chain reaction. The clonal relationship of clinical isolates was studied by Pulsed Field Gel Electrophoresis.
  
  
  RESULTS
  The results showed that 93.84% (n = 61) isolates of K. pneumoniae were positive for the blaCTX-M-1 group. One isolate showed PCR signals for blaCTX-M-25 group. None of our isolates were positive for CTX-M groups 2, 8 and 9. The majority of blaCTX-M positive isolates were genetically unrelated and no epidemic clones were identified.
  
  
  CONCLUSIONS
  This study reports the emergence of CTX-M groups 1 and 25 producing isolates of K. pneumoniae with genetic diversity in Karachi, Pakistan.
authors.affiliation: Department of Pathology/Microbiolog, Aga Khan University Hospital, Karachi, Pakistan. erum.khan@aku.edu
authors.forename: Erum
authors.initials: E
authors.lastname: Khan
authors.forename: Thamarai
authors.initials: T
authors.lastname: Schneiders
authors.forename: Afia
authors.initials: A
authors.lastname: Zafar
authors.forename: Erum
authors.initials: E
authors.lastname: Aziz
authors.forename: Asra
authors.initials: A
authors.lastname: Parekh
authors.forename: Rumina
authors.initials: R
authors.lastname: Hasan
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D015373:Bacterial Typing Techniques; D001769:Blood / Q000382:microbiology; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D014644:Genetic Variation; D005838:Genotype; D006761:Hospitals; D006801:Humans; D007231:Infant, Newborn; D007710:Klebsiella Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D010154:Pakistan; D016133:Polymerase Chain Reaction / Q000379:methods; D011446:Prospective Studies; D014132:Trachea / Q000382:microbiology; D014556:Urine / Q000382:microbiology; D014947:Wounds and Injuries / Q000382:microbiology; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C055184:beta-lactamase TEM-3; D001618:beta-Lactamases