Effect of Temperature on Carbapenemase-Encoding Plasmid Transfer in Klebsiella pneumoniae

Bacteria causing human infections can develop antibiotic resistance due to various factors. Temperature affects bacterial growth and gene transfer; however, studies exploring the association between the changes in local temperature and antibiotic resistance are limited. Here, we investigated the effects of local temperatures on the distribution of antibiotic resistance and transmission of carbapenemase-producing Enterobacterales using the data on Klebsiella pneumoniae from sentinel hospitals in eight regions included in the Korea Global Antimicrobial Resistance Surveillance System between 2017 and 2021. The resistance rates to most antibiotics, including carbapenems, varied significantly according to local temperature (p < 0.047), except for aminoglycosides. Conjugation experiments at various temperatures for strains encoding the carbapenemase gene on a plasmid revealed significant variation in the optimal conjugation temperatures for plasmids carrying bla_KPC and bla_NDM genes. The optimal conjugation temperatures demonstrating the highest stability for bla_KPC- and bla_NDM-carrying plasmids were 25 °C (p = 0.030) and 30 °C (p = 0.007), respectively. The stability of bla_KPC-IncF was higher at 25 °C than that at 30 °C (p = 0.032) or 37 °C (p = 0.047), while bla_KPC-IncX3 exhibited the lowest stability at 37 °C (p = 0.047). bla_NDM-IncX3 was more stable at 30 °C than at 37 °C (p = 0.049). These findings suggest that the optimal temperature for carbapenemase gene transmission varied between 25 °C and 30 °C, indicating that warmer seasons promote the transfer of more antibiotic resistance-related genes and highlighting the importance of local temperature in the spread and transmission of plasmids carrying carbapenemases.