What is it about?

Moraxella catarrhalis is one of the bacterial pathogens associated with childhood pneumonia, but its clinical importance is not clearly defined. Therefore, we conducted a retrospective, cross‐sectional study to investigate the microbiologic and virulence characteristics of M. catarrhalis isolates from induced sputum samples of children with pneumonia, enrolled in the Pneumonia Etiology Research for Child Health study in Lusaka, Zambia between 2011 and 2014. Our study observed that M. catarrhalis isolates were the predominant bacteria in good‐quality sputum samples analysed. We also found that 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%). The findings provide supportive evidence for the pathogenic potential role of M. catarrhalis in pediatric pneumonia. High multidrug resistance was also observed amongst the isolates, which can result in affected patients not responding to standard treatment, leading to prolonged illness, increased healthcare costs, and risk of death.

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Why is it important?

Correct diagnosis of M. catarrhalis infection is important since it is impossible to identify these infections based on presumptive diagnosis alone Therefore, this study will provide physicians with insightful data on the clinical importance these newly emerged bacterial pathogens. Our study also underscore the need to identify M. catarrhalis as a possible lower respiratory tract pathogen particularly in children. Knowledge of the antimicrobial susceptibility patterns is needed to guide empirical antimicrobial therapy.


To our knowledge this was the first study to examine the pathogenic and antimicrobial characteristics of M. catarrhalis in Zambia.

Nawa Mukena

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This page is a summary of: Microbiologic and virulence characteristics of Moraxella catarrhalis isolates from Zambian children presenting with acute pneumonia, Pediatric Pulmonology, September 2022, Wiley, DOI: 10.1002/ppul.26138.
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