Nasopharyngeal carriage of Moraxella catarrhalis is a risk factor for
upper respiratory tract infections and
otitis media. In this study, we aimed to characterize BRO
beta-lactamases of M. catarrhalis strains isolated from 64 children without any symptoms of respiratory disease. Gram negative diplococci grown on selective media and which are
catalase,
oxidase,
DNase,
nitrate reduction positive,
glucose,
maltose,
sucrose and
lactose fermentation negative, were diagnosed as M. catarrhalis.
Antibiotic susceptibility testing was performed by
agar dilution method recommended by NCCLS. BRO
beta-lactamases were differentiated by restriction
enzyme analysis method. The resistance rate for
ampicillin was 18.8% and all the isolates were found to be sensitive to
amoxicillin-
clavulanate,
cefazolin,
cefaclor,
azithromycin and
ciprofloxacin. Out of 64 M. catarrhalis isolates, 57 (89%) were found
beta-lactamase positive with
nitrocefin disk test (Remel, USA). The presence of BRO
beta-lactamases in these 57 strains (89%) was also confirmed by restriction
enzyme analysis, while 7 (11%) of them were found to be negative. Among the positive strains, 47 (73.4%) were typed as BRO-1, and 10 (15.6%) were typed as BRO-2. The characterization of BRO
beta-lactamases of M. catarrhalis strains in carrier children is important since the high rate of carriage predisposes to
respiratory tract infections. As a result,
BRO beta-lactamase typing will guide the treatment regimen against the
respiratory infections that can occur due to M. catarrhalis in carrier children.