TITLE:
Mapping Antibiotic Resistance Genes in Bacteria of Medical Interest and the Evolution of Healthcare-Associated Infections in Chad: 2012 to 2025
AUTHORS:
Bessimbaye Nadlaou, Boilengar Djimenan, Togde Gildas le Djimbaye, Keloumta Mantangar Clarisse, Kirga Kabo Abakar, Bakarnga-Via Issakou, Yandaï Fissou Henry, Michel Kiréopori Gomgnimbou, Abdelsalam Tidjani, Ali Mahamat Moussa, Vittorio Colizzi, Choua Ouchemi
KEYWORDS:
Mapping, Resistance Gene, MDR, PDR, XDR, Antimicrobial, Healthcare-Associated Infections, Chad
JOURNAL NAME:
American Journal of Molecular Biology,
Vol.16 No.2,
February
24,
2026
ABSTRACT: Multidrug-resistant (MDR), highly resistant (XDR), and pan-resistant (PDR) bacteria to antimicrobials are a major public health problem worldwide, particularly in America, Africa, Europe, Russia, and Chad, due to their prevalence, impacts, difficulties in therapeutic management, and socio-economic consequences. This was a descriptive, cross-sectional, and etiological diagnostic study conducted from January 17, 2012, to December 7, 2025, at the bacteriology and mycobacteria laboratories of the National Reference Hospital Center (CHURN) of N’Djamena, and at the Bacteriology Unit of the Laboratory for Research, Diagnostic and Scientific Expertise (Labo-ReDES) of the Faculty of Human Health Sciences (FSSH) of the University of N’Djamena, following standard phenotypic and molecular methods of clinical microbiology. The objective of this study was to produce a map of resistance genes of MDR, XDR, and PDR to antimicrobials and healthcare-associated infections from 2012 to 2025 in Chad. In the study, 851 resistant bacterial phenotypes were identified, including 329 MDR bacteria, 407 ESBL, 114 XDR bacteria, and 10 PDR. The emerging resistant bacteria identified were: Staphylococcus aureus (65%), Escherichia coli (90%), Klebsiella pneumoniae (25%), Enterobacter cloacae (8%), Salmonella spp. (18%), Acinetobacter baumannii (2%), and Shigella flexneri (21%). The identified CREs were: Enterococcus (11%) and carbapenemase-producing Enterobacteriaceae (Escherichia coli, Enterobacter, Serratia, etc.). Vibrio cholerae (25%) and Neisseria menigitidis (34%) were also present. The detected resistance genes were those of: Mycobacterium tuberculosis (rpoB, inhA, KatG/inhA, gyrA and gyrB, rrs and eis), Mycobacterium leprae (rpoB, flop1, gyrA and gyrB), and the chloride toxin-producing genes of Vibrio cholerae (ctxA, ctxB, gyrA, gyrB), Staphylococcus and Enterobacteriaceae (E. coli, Klebsiella, Enterobacter, etc.: mecA, ACC (6') and Enterococcus (vanA). The results of this study highlight the importance of mandating adherence to antituberculosis and antileprosy medications for patients, requiring prescribers to prescribe based on laboratory evidence, and ultimately, urging policymakers to organize laboratories in the country’s 23 provinces and equip them with high-performance diagnostic tools. The data from this study should also encourage national programs in Chad, Africa, and around the world to activate the BMR, XDR, and PDR surveillance system.