Resistance profile of Gram-negative bacteria.

BackgroundWe previously showed that the presence of secondary bacteria influences clinical outcome in Buruli ulcer (BU) patients. Despite this, there is limited data on the antimicrobial resistance of these bacterial isolates within BU lesions. To gain understanding of antimicrobial resistance in BU, we longitudinally profiled antimicrobial resistance in frequently isolated bacterial organisms from these lesions.Methodology/Principal findingsBetween August 2021 and June 2024, we assessed the antimicrobial resistance of pathogenic bacterial isolates within lesions of laboratory confirmed BU patients in Ghana. Wound swabs were collected longitudinally. The bacteria were identified and their antibiotic susceptibility tested using the VITEK 2 compact. Of the 166 bacterial isolates, eight bacterial species were identified comprising 56.9% Gram negative bacilli and 43.1% Gram positive cocci. We found the presence of pathogenic bacteria with varying levels of resistance to commonly used antibiotics in BU lesions before, during and after BU-specific antibiotic treatment. At baseline, all bacterial isolates were resistant to at least one antibiotic. Notably, Extended Spectrum Beta-Lactamase (ESBL) production was detected in 30% of Gram-negative isolates tested while 50% of the Staphylococcus aureus isolates tested positive for MRSA. There was a decline in the ESBL positive isolates over time (from 30% to 0) whereas MRSA positive isolates increased after treatment in the lesions (from 50% to 60%).Conclusions and significanceResults from this study highlight a concerning prevalence of antimicrobial resistant bacteria, including multi drug resistant (MDR), ESBL-positive and Methicillin-resistant Staphylococcus aureus (MRSA) pathogens, in Buruli ulcer lesions. These findings underscore the urgent need for the development of integrated guidelines to guide surveillance and treatment of secondary bacterial infections to further improve outcomes in BU.