Abstract
BACKGROUND: Antibiotic resistance in multidrug-resistant Klebsiella pneumoniae (MDR-KP), particularly against carbapenems and colistin, is a critical concern, increasing morbidity and mortality among hospitalized patients. This systematic review aims to identify methylase genes in K. pneumoniae and examine their co-existence with β-lactamase and carbapenemase genes contributing to antibiotic resistance. METHODS: A literature search was conducted across three electronic databases from inception until 6 December 2023. The quality assessment followed Critical Appraisal Skills Programme (CASP) criteria. Studies focusing on methylase genes and antibiotic resistance in K. pneumoniae were included. Two authors independently screened titles, abstracts, and full texts, with a third resolving disagreements. RESULTS: Thirty-four studies met the inclusion criteria. Methylase genes in K. pneumoniae isolates were predominantly reported in Europe and Asia, particularly in Iran, China, Japan, and India (8.8%, N = 3). The most prevalent 16S rRNA methyltransferase genes identified were armA (76.5%, N = 26), rmtB (61.8%, N = 21), and rmtC (29.4%, N = 10). Common extended-spectrum β-lactamase (ESBL) genes included bla(CTXM) (64.7%, N = 22) and bla(SHV) (47%, N = 16), while bla(KPC) (26.5%, N = 9) and bla(NDM) (23.5%, N = 8) were the predominant carbapenemase genes. The coexistence of methylase genes with ESBL and carbapenemase genes conferred significant resistance to aminoglycosides (gentamicin, kanamycin, tobramycin, amikacin, arbekacin), cephalosporins (cefazolin, cefoxitin, cefotaxime), and carbapenems (imipenem, meropenem). CONCLUSIONS: The widespread distribution of resistance mechanisms in K. pneumoniae highlights a global challenge, emphasizing the need for strategic antimicrobial use to reduce resistance rates.