World Health Organization bacterial priority pathogens in skin and soft tissue infections: prevalence, antimicrobial resistance, and risk factors in Mwanza, Tanzania.

OBJECTIVES

Antimicrobial resistance, particularly among World Health Organization bacterial priority pathogens (WHO BPPs), poses a major global health threat. We assessed the epidemiology of wound infections, including bacterial profiles, WHO BPP burden, and associated factors, during and after the implementation of the National Action Plan on Antimicrobial Resistance (NAP-AMR) in Mwanza, Tanzania.

METHODS

A cross-sectional study was conducted during (June 2019 to June 2020) and after (March to August 2023) NAP-AMR. Pus samples were cultured aerobically. Isolates were identified using Vitek mass spectrometry and 16S ribosomal ribonucleic acid sequencing. Antimicrobial susceptibility testing and minimum inhibitory concentrations were determined using Vitek 2.

RESULTS

Among 630 patients (median age 29 years; interquartile range 15-47), 257 (40.8%) had positive cultures. Skin and soft tissue infections increased significantly after NAP-AMR (27.8% vs 68.3%, P < 0.001). Resistance to third-generation cephalosporins (3GCs) increased significantly in Escherichia coli (P < 0.05). Additionally, meropenem resistance among Gram-negative bacteria increased from 2.6% to 21.0% (P = 0.327), primarily attributable to the increased isolation of Acinetobacter spp. and Pseudomonas aeruginosa after NAP-AMR. WHO BPPs accounted for 45.2% of isolates, and extended-spectrum beta-lactamase-producing Enterobacterales increased significantly (64.8% vs 82.5%, P = 0.025), particularly in higher-tier hospitals (45.4% vs 77.9%, P = 0.002).

CONCLUSION

After NAP-AMR, we recorded significant increases in resistance to 3GCs among E. coli, increased resistance to meropenem among Gram-negative bacteria (notably Acinetobacter spp. and P. aeruginosa), and a high proportion of WHO BPPs, particularly extended-spectrum beta-lactamase-producing Enterobacterales, potentially reflecting improved diagnostics, enhanced laboratory capacity, or heightened antimicrobial use during the coronavirus disease 2019 pandemic. These findings underscore the need for sustained surveillance and strengthened antimicrobial stewardship.