A systematic review of the role of methylase genes in antibiotic resistance: co-existence with extended spectrum β-lactamase and carbapenemase genes in Klebsiella pneumoniae.

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 blaCTXM (64.7%, N = 22) and blaSHV (47%, N = 16), while blaKPC (26.5%, N = 9) and blaNDM (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.