Molecular Characterization of MDR Enterobacter spp. Isolated from Clinical Specimens in Sudan: Prevalence of CTX-M and Carbapenemase Genes with Absence of SHV and TEM.

Introduction: The rise of Multidrug-resistant (MDR) Enterobacter species is a significant global health concern, particularly in hospital settings where they contribute to nosocomial infections. This study aimed to determine the prevalence of MDR Enterobacter spp. in clinical specimens from Khartoum State, Sudan, to detect key resistance genes (CTX-M, AmpC, OXA-48, NDM-1, VIM, IMP, MCR-1, SHV, and TEM), and to analyze the correlation between genotypic and phenotypic resistance patterns.

Methods: A cross-sectional, laboratory-based study was conducted from February to October 2021. A total of 384 clinical specimens, including urine, wound swabs, sputum, and blood, were collected from hospitals in Khartoum. Enterobacter spp. isolates were identified using conventional methods such as colony morphology, Gram staining, and biochemical tests. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method. Multiplex Polymerase Chain Reaction (PCR) was employed to detect ESBL genes (CTX-M, SHV, TEM, AmpC) and carbapenemase genes (OXA-48, NDM-1, VIM, IMP, MCR-1).

Results: Among the 384 clinical specimens, 14 (3.6%) were confirmed as Enterobacter spp. by PCR. All isolates exhibited multidrug resistance. CTX-M was detected in 100% of isolates, while SHV and TEM genes were absent. Other detected resistance genes included AmpC in 5 isolates (35.7%), IMP in 2 (14.3%), NDM-1 in 3 (21.4%), VIM in 5 (35.7%), OXA-48 in 7 (50.0%), and MCR-1 in 13 (92.9%). The predominance of CTX-M, car-bapenemase genes, and the absence of SHV and TEM suggest a distinct resistance profile in these isolates.

Discussion: The findings highlight a concerning emergence of MDR Enterobacter spp. in Sudan, primarily driven by the widespread presence of CTX-M and carbapenemase genes. The lack of SHV and TEM genes indicates potential regional differences in genetic resistance patterns. This underscores the critical need for molecular monitoring and effective infection control policies.

Conclusion: The high prevalence of MDR Enterobacter spp., particularly due to CTX-M and carbapenemase gene expression, poses a serious threat to public health in Khartoum. Regional variation in resistance mechanisms, such as the absence of SHV and TEM, necessitates targeted antimicrobial stewardship and the development of localized treatment guidelines to limit the spread of resistance in Sudanese healthcare facilities.