Background: Moraxella catarrhalis is one of the bacterial pathogens associated with childhood pneumonia, but its clinical importance is not clearly defined. Objective: This study aimed to investigate the microbiologic and virulence characteristics of M. catarrhalis isolates obtained from children with pneumonia in Lusaka, Zambia. Methods: This retrospective, cross-sectional study analyzed 91 M. catarrhalis isolates from induced sputum samples of children less than 5 years of age with pneumonia enrolled in the Pneumonia Etiology Research for Child Health study in Lusaka, Zambia between 2011 and 2014. Bacteria identification and virulence genes detection were performed by PCR and DNA sequencing, while antimicrobial susceptibility testing was determined by the Kirby-Bauer method.Results: All the M. catarrhalis isolates were obtained from good-quality sputum samples and were the predominant bacteria. These isolates harbored virulence genes copB (100%), ompE (69.2%), ompCD (71.4%), uspA1 (92.3%), and uspA2 (69.2%) and were all β-lactamase producers. They showed resistance to ampicillin (100%), amoxicillin (100%), trimethoprim-sulfamethoxazole (92.3%), ciprofloxacin (46.2%), chloramphenicol (45.1%), erythromycin (36.3%), tetracycline (25.3%), cefuroxime (11.0%), and amoxicillin-clavulanate (2.2%), with 71.4% displaying multi-drug resistant phenotype but all susceptible to imipenem (100%).
Conclusion:This study showed that M. catarrhalis isolates were the predominant or only bacterial isolates from the sputum samples analyzed. The findings provide supportive evidence for the pathogenic potential role of this bacterium in pediatric
IntroductionAntimicrobial resistance (AMR) is a growing public health problem in low-to-middle income countries which have a high burden of infectious diseases. Poor antimicrobial stewardship in these regions has resulted in a rise in reported cases of AMR creating a need for country specific data to inform policy on the strategies of combating AMR. Here we show antimicrobial susceptibility patterns of Shigella, and E. coli isolated from stools of children under 5 years of age and adults. MethodsThe study was nested under an enterotoxigenic Escherichia coli (ETEC) vaccine clinical trial and diarrhoea surveillance. Stool samples were collected at baseline, during scheduled visits and whenever the participants presented with diarrhoea as per study design. Following microbiological techniques for culture and microorganism identification, pure colonies were run on the BD Phoenix™ 100 for identification and antimicrobial susceptibility. For ETEC identification, colony PCR was done on all E. coli positive samples using heat-labile toxin and stable toxin specific primers, respectively.ResultsAmong the 211 samples analysed, 52.5% were from individuals with diarrhoea. Un-typed E. coli were the most common organism isolated (63.6%), followed by ETEC (12.7%) and 4.8% were Shigella sp. Majority of the organisms isolated were either susceptible or intermedial (80-100%) to all tested antibiotics except for Trimethoprim/Sulfamethoxazole which showed a high resistance of 82 – 93%. We also observed some multi-drug resistance (3.5%) among all organisms tested to the different antibiotics.ConclusionsThe observed high prevalence of co-trimoxazole resistance and intermedial susceptibility to fluoroquinolones among ETEC, Shigella and other un-typed E. coli isolates, is critical for informing policy on the urgent need for antimicrobial stewardship and strengthening of AMR surveillance systems in Zambia.
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