title: β-Lactamase production and antimicrobial susceptibility pattern of Moraxella catarrhalis isolates: report from Pakistan.
abstract: OBJECTIVE
  To assess the frequency of β-lactamase production and antimicrobial resistance in Moraxella catarrhalis isolated from clinical specimens in Pakistan.
  
  
  METHODS
  This cross sectional study (January to December 2010) was conducted in clinical microbiology laboratory of Aga Khan University Hospital. A total of 97 clinical respiratory specimens growing Moraxella catarrhalis were included. Frequency of β-lactamase production and antimicrobial resistance rates against ampicillin, erythromycin, ciprofloxacin and tetracycline were noted by performing minimum inhibitory concentration (MIC). MICs were calculated as MIC50 and MIC90.
  
  
  RESULTS
  β-Lactamase production was detected in 84% of isolates, which correlated well with high MIC of ampicillin. Majority of isolates were susceptible to erythromycin (97%) and tetracycline (96%) with MIC90=0.12 mg/L and MIC90=1 mg/L respectively. All isolates were found susceptible to ciprofloxacin (MIC90=0.06 mg/L).
  
  
  CONCLUSIONS
  Result suggests that empirical use of ampicillin should be discouraged while treating respiratory tract infections. This also emphasizes the importance of continuous surveillance in order to detect emerging resistance in Moraxella isolates.
authors.affiliation: Department of Pathology and Microbiology, Aga Khan University Hospital, Karachi, Pakistan.
authors.forename: Sadia Omer
authors.initials: SO
authors.lastname: Sheikh
authors.affiliation: Department of Pathology and Microbiology, Aga Khan University Hospital, Karachi, Pakistan.
authors.forename: Naima
authors.initials: N
authors.lastname: Fasih
authors.affiliation: Department of Pathology and Microbiology, Aga Khan University Hospital, Karachi, Pakistan.
authors.forename: Seema
authors.initials: S
authors.lastname: Irfan
authors.affiliation: Department of Pathology and Microbiology, Aga Khan University Hospital, Karachi, Pakistan. Electronic address: afia.zafar@aku.edu.
authors.forename: Afia
authors.initials: A
authors.lastname: Zafar
keywords: Antimicrobial resistance in Pakistan; Moraxella catarrhalis; Moraxella catarrhalis resistance pattern in Pakistan; β-lactamase enzyme