Prevalence, resistance, and biofilm production of ESKAPE pathogens in community-acquired pneumonia at Adama Hospital, Central Ethiopia

Abstract

Background: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species pathogens (ESKAPE) pose a serious global public health threat. However, data on their distribution, antimicrobial resistance, and biofilm formation remain scarce in Ethiopia. Therefore, this study investigated these parameters in patients with clinically diagnosed community-acquired pneumonia (CAP) at Adama Hospital Medical College, Central Ethiopia, over one year (November 2022–November 2023).

Methods: A hospital-based cross-sectional study enrolled consecutive eligible adults until the sample size was reached. Demographic and clinical data were collected with a pretested structured questionnaire. Sputum was obtained by instructed expectoration into sterile containers. ESKAPE pathogens were identified by colony morphology, Gram stain, and biochemical tests. Antimicrobial susceptibility was assessed by the Kirby–Bauer disk diffusion method. Biofilm formation was measured using a 96-well microtiter plate assay with glucose-supplemented tryptic soy broth, crystal violet staining, and spectrophotometric quantification of optical density. Data were entered in Microsoft Excel and analyzed with SPSS v26.

Results: Out of 117 positive cultures, 50 (42.7%; 95% CI: 33.6–52.2) were ESKAPE pathogens. Species distribution among the 50 isolates: Staphylococcus aureus (15; 30%); all were methicillin-resistant Staphylococcus aureus; Klebsiella pneumoniae (12; 24%); Pseudomonas aeruginosa (11; 22%); Enterobacter spp. (11; 22%); and Acinetobacter baumannii (1; 2%). Multidrug resistance (MDR) was present in 30/50 (60%; 95% CI: 45.2–73.6%), with K. pneumoniae the most common MDR organism and P. aeruginosa the least. Biofilm production was detected in 45/50 (90%; 95% CI: 78.2–96.7%): 26 (52%) strong, 13 (26%) moderate, and 6 (12%) weak producers.

Conclusion: This study revealed a high prevalence of multidrug-resistant, biofilm-producing ESKAPE pathogens in community-acquired pneumonia patients in Central Ethiopia. The findings highlight critical challenges for empirical treatment in resource-limited settings and emphasize the urgent need for ongoing surveillance and antimicrobial stew­ardship programs.