Molecular Detection of Carbapenemase Genes in Gut Enterobacteriaceae among Patients with Selected Mental Disorders

Abstract

Background: Antimicrobial resistance among Enterobacterales remains a growing public health concern, particularly in vulnerable clinical populations. Purpose: Psychiatric inpatients may be at increased risk of colonization with multidrug-resistant organisms due to prolonged hospitalization and healthcare exposure, yet data on their bacterial profiles and resistance patterns remain limited in Nigeria. Methods: One hundred and two (102) fecal samples and biodata were collected from inpatients diagnosed with four selected mental disorders. Samples were cultured on EMB agar, and isolates were identified following standard microbiological procedures. An antibiotic sensitivity test was carried out by the Kirby-Bauer disc diffusion method. Multidrug-resistant (MDR) isolates were screened for carbapenemase production, which was distinguished by two phenotypic tests. Five selected phenotypes were further amplified for the presence of blaOXA-48, blaNDM, blaKPC, and blaIMI using the polymerase chain reaction technique. Results: A higher percentage of the study participants (71.5%) were males, while 28.4% were females. A total of 102 Enterobacteriaceae bacteria were isolated and identified as Escherichia coli (43.1%), Klebsiella spp. (28.4%), Enterobacter spp. (10.7%), Proteus spp. (8.8%), Salmonella spp. (7.8%), and Shigella spp. (0.9%). Varying resistant patterns were observed among the isolates, with β-lactams having the highest frequency (51.0%), while the least resistance was recorded in chloramphenicol (24.4%). A total of 56 bacterial isolates (59.5%) were MDR, out of which 45 (80.3%) were carbapenem-resistant. Out of these, 41 (73.2%) were confirmed carbapenemase producers. Carbapenemase phenotypes recorded 48.2% and 7.1% as MBL and OXA-48 producers, respectively. Conclusion: Carbapenemase genes were detected in all five selected multidrug-resistant Enterobacterales.