Nasal colonization and antimicrobial susceptibility profile of Staphylococcus aureus among healthcare workers at selected health institutions in Bahir Dar, Northwest Ethiopia

Abstract

Staphylococcus aureus (S. aureus) is a leading cause of healthcare- and community-acquired infections, ranging from mild skin conditions to severe systemic disease. Healthcare workers are frequently colonized, serving as potential reservoirs for transmission to patients, attendants, and colleagues. Nasal screening is a key strategy in controlling Methicillin-Resistant Staphylococcus aureus (MRSA), yet data remain scarce in the study area. The aim of this study was to determine the prevalence of nasal colonization and the antimicrobial susceptibility profile of S. aureus among healthcare workers in selected health institutions in Bahir Dar, Northwest Ethiopia. An institution-based cross-sectional study was conducted from April to July 2023 among 249 Healthcare workers. A systematic random sampling was employed to include study participants. The nasal samples were collected and processed following standard bacteriological procedures. Antimicrobial susceptibility testing was performed using a disk diffusion method on Mueller Hinton Agar. Data were coded, entered, and analyzed using the SPSS version 27 statistical package. Logistic regression analysis was done to identify factors associated with nasal colonization by S. aureus and p < 0.05 was considered statistically significant. Colonization with S. aureus and MRSA was 15.7% (39/249) and 3.2% (8/249); respectively. From the S. aureus isolates, 20.5% (8/39) were MRSA. Of the S. aureus isolates, 82.1% (32/39) were resistant to Penicillin. About 30.8% isolates were multi-drug resistant (MDR). On the other hand, 89.7% (35/39) of the isolates were sensitive to Clindamycin, 89.7% (35/39) to Chloramphenicol, and 87.2% (34/39) to Ciprofloxacin. Infrequent hand-washing habits after patient contact (AOR = 6.770, 95% CI: 2.054–22.311; p = 0.002), Working in health center (AOR = 4.125, 95% CI: 1.390-12.245; p = 0.011) and frequent nose-picking habits (AOR = 3.378, 95% CI: 1.276–8.949; p = 0.014) were significantly associated with nasal colonization with S. aureus . The nasal colonization rate of S. aureus and MRSA was lower than previous studies in the Amhara region. The isolates were relatively susceptible to Clindamycin, Chloramphenicol, and Ciprofloxacin. Infrequent hand-washing habits after patient contact, working in the health center and frequent nose-picking habits were significantly associated with nasal colonization with S. aureus . Hygienic activities should be practiced to prevent colonization and cross-transmission.