# WHO priority pathogens, ESKAPE bacteria, and antimicrobial resistance surveillance in household wastewater, Gombe, Nigeria

## TL;DR

This study finds high levels of antibiotic-resistant bacteria in household wastewater in Gombe, Nigeria, highlighting a public health concern.

## Contribution

The study provides the first comprehensive surveillance of WHO priority pathogens and antimicrobial resistance in household wastewater from Gombe, Nigeria.

## Key findings

- E. coli was the most common WHO priority pathogen detected in wastewater samples.
- High rates of multidrug resistance were observed in K. pneumoniae and E. coli, with significant carbapenem resistance.
- ESBL and carbapenemase genes were frequently detected among priority pathogens.

## Abstract

Background. World Health Organization (WHO) priority bacterial pathogens and ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) organisms in household wastewater pose critical community transmission risks, yet surveillance data from Sub-Saharan Africa remain limited. This study provides the first comprehensive priority pathogen detection and antimicrobial resistance assessment in household wastewater from Gombe State, Nigeria, focusing on organisms of highest clinical concern.

Methods. We conducted targeted surveillance for WHO priority pathogens in 320 household wastewater samples across seven districts in Gombe using multi-stage sampling. Some priority Gram-negative pathogens (Escherichia coli, K. pneumoniae, P. aeruginosa and Enterobacter spp.) were specifically isolated and characterized. Antimicrobial susceptibility testing followed Clinical and Laboratory Standards Institute (CLSI) 2024 guidelines across 12 antibiotics targeting critical resistance patterns. Extended-spectrum beta-lactamase (ESBL) and carbapenemase detection focused on priority pathogen isolates, with PCR confirmation of key resistance genes.

Results. Priority pathogen detection revealed E. coli (131 isolates, 32.6%) as the dominant WHO priority pathogen, followed by K. pneumoniae (77 isolates, 19.2%) and P. aeruginosa (45 isolates, 11.2%). The ESKAPE pathogen P. aeruginosa showed 73.3% multidrug resistance (MDR), with carbapenemase gene detection [Verona integron-encoded metallo-beta-lactamase gene (blaVIM), 60%; K. pneumoniae carbapenemase gene (blaKPC), 20%]. The critical priority pathogen K. pneumoniae demonstrated a 79.2% MDR prevalence, with universal beta-lactamase CTX-M gene (blaCTX-M) gene presence (100%) among ESBL producers. Priority pathogen E. coli exhibited an alarming 84.7% MDR rate, with widespread ESBL production (51.5%). Carbapenem resistance among priority pathogens reached 41.3%, indicating last-resort antibiotic failure in critical organisms.

Conclusions. Household wastewater in Gombe harbours WHO priority pathogens and ESKAPE organisms with high antimicrobial resistance prevalence. These preliminary findings suggest substantial environmental circulation of resistant bacteria and highlight the need for enhanced surveillance, further investigation of community transmission risks and strengthened antimicrobial stewardship programmes.