Molecular Analysis of Tigecycline Resistance in Carbapenem-Resistant Enterobacterales (CRE) in Mthatha and Surrounding Hospitals

<b>Background:</b> The emergence of carbapenem-resistant <i>Enterobacterales</i> is prevalent and poses a significant threat to health systems worldwide. This study aimed to conduct a molecular analysis of tigecycline resistance in 100 CRE isolates from Mthatha Hospital and surrounding hospitals. <b>Methods</b>: A retrospective study among patients who attended Nelson Mandela Academic Hospital (NMAH) and Mthatha Regional Hospital (MRH), Eastern Cape, South Africa. <i>Enterobacterales</i> isolates were identified using the Vitek2^® system (bioMérieux); an E-test was performed on 100 CRE isolates according to the manufacturer's instructions. PCR assays for rapid detection of <i>tet(X)</i> and its variants, including <i>tet(X1)</i> and <i>tet(X2)</i>, and high-level tigecycline resistance genes <i>tet(X3)</i>, <i>tet(X4)</i>, and <i>tet(X5)</i> were developed. <b>Results:</b> The results show a notably high prevalence of CRE infections in neonatal, male surgical, and maternal and pediatric wards, predominantly driven by <i>Klebsiella</i> species (53.4%), followed by <i>Enterobacter</i> species (20.5%) and then <i>Escherichia coli</i> (6.7%), and 7.2% of CRE isolates were resistant to tigecycline (E-test). In this study, <i>tet(X)</i> genes were not identified as the primary mechanism of tigecycline resistance. The risk factors associated with tigecycline resistance in CRE include age, pre-exposure to antibiotics, prolonged hospitalization, and undergoing invasive procedures, indicated by strong r = 0.9501. <b>Conclusions:</b> CRE gradually evolves, posing a significant threat to patients of all ages; early detection of carbapenemase production in clinical infections, carriage states, or both is essential to prevent hospital-based outbreaks.