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Antimicrobial susceptibility of Moraxella catarrhalis isolated from children in Kalgoorlie–Boulder, Western Australia

Pingault, N.M., Bowman, J.M., Lehmann, D. and Riley, T.V. (2010) Antimicrobial susceptibility of Moraxella catarrhalis isolated from children in Kalgoorlie–Boulder, Western Australia. Pathology, 42 (3). pp. 273-279.

Link to Published Version: http://dx.doi.org/10.3109/00313021003631270
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Abstract

Aim: To investigate antimicrobial susceptibility of Moraxella catarrhalis isolated from a cohort of children being followed in a study of the natural history of otitis media in a semi-arid region of Western Australia.

Methods: In the Kalgoorlie Otitis Media Research Project nasopharyngeal aspirates were collected from children up to seven times between the age of 1 week and 2 years. A total of 261 M. catarrhalis strains from 50 Aboriginal and 50 non-Aboriginal children were tested against 14 antibiotics using the Clinical and Laboratory Standards Institute (CLSI) agar dilution method.

Results: All strains were susceptible to amoxicillin/clavulanate, cefuroxime, azithromycin, ciprofloxacin, moxifloxacin, levofloxacin, erythromycin and minocycline. While no criteria exist for assessment of susceptibility to roxithromycin, minimum inhibitory concentrations (MICs) were low. Approximately 46% of strains from Aboriginal children and 27% from non-Aboriginal children appeared susceptible to ampicillin. A small number of strains was intermediately resistant to cefaclor (9/261, 3.4%), while the bulk of strains was intermediately resistant to co-trimoxazole. A low prevalence of tetracycline resistance (3/261, 1.1%) was noted. β-lactamase production was observed in 97.7% of strains.

Conclusions: While M. catarrhalis strains from children of the Kalgoorlie region were susceptible to many of the antibiotics used to treat respiratory tract infections, a large proportion of strains were resistant to ampicillin and/or co-trimoxazole. Current therapeutic guidelines, which recommend amoxicillin for treatment of otitis media, may need to be revised.

Publication Type: Journal Article
Publisher: Elsevier
Copyright: © 2010 Royal College of Pathologists of Australasia
URI: http://researchrepository.murdoch.edu.au/id/eprint/35347
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