Asymptomatic faecal carriage of multidrug-resistant and carbapenemase-producing Gram-negative bacteria among inpatients and outpatients in a Kenyan county referral hospital: a cross-sectional study

BACKGROUND: Carbapenem-resistant Gram-negative bacteria, particularly the carbapenemase producers, are increasingly a global public health concern. However, there is limited epidemiological data to inform infection prevention and control interventions in resource-constrained settings. This study assessed asymptomatic faecal carriage and associated factors of multidrug-resistant (MDR) and carbapenemase-producing Gram-negative bacteria (CP-GNB) among inpatients and outpatients in a Kenyan county referral hospital. METHODS: This was a hospital-based cross-sectional study among 310 adult participants (155 inpatients and 155 outpatients) at Kiambu County Referral Hospital, Kenya, from June to September 2022. The study excluded outpatients with histories of diarrhoea, antibiotics use (≤ 48 h), and hospitalization within 90 days of sampling. Inpatients presenting with diarrhoea and those admitted for ≤ 48 h were also excluded. Stool samples were cultured on MacConkey media supplemented with meropenem (1 mg/L). Carbapenemase production of the isolates was confirmed using both modified and optimized Carbapenem Inactivation Methods. Automated platforms were used for identification and antimicrobial susceptibility testing of the isolates. RESULTS: The overall asymptomatic faecal carriage of CP-GNB was 5.8%, 95% Confidence Interval (CI): 3.20-8.41 (18/310), highest among inpatients (9.7%, 95% CI: 5.02-14.33 (15/155)), p = 0.009. Enterobacter cloacae subsp. dissolvens and Acinetobacter baumannii were the predominant isolates. All the isolates were MDR. Patients admitted after referral from other facilities had higher odds of CP-GNB carriage compared to those admitted to the maternity ward (adjusted odds ratio = 49.03, 95% CI: 3.17-159.23, P = 0.031). CONCLUSION: Asymptomatic faecal carriage of MDR and CP-GNB was most prevalent among inpatients. Inter-hospital transfer significantly increased the risk of colonization. Antimicrobial stewardship to reduce unnecessary carbapenem use, as well as strict adherence to infection prevention and control protocols to limit the inter-hospital spread of drug-resistant bacteria, are urgently required in this study area and similar settings.