Abstract
Background : the existence of 16S rRNA methylase genes would increase treatment difficulty of patients infected with CR-hvKP strains, this study was aimed to testify the prevalence of the 16S rRNA methylase genes genes in the CR-hvKP strains in China.Methods : Thirty-nine carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) isolates collected from a Chinese hospital during the whole year of 2018 were evaluated to characterize the prevalence of 16S rRNA methylase genes. Results : In tatal 66.7% (26/39) of the CR-hvKP isolates were found to carry 16S rRNA methylase genes, and the most frequently detected gene was armA (11,42.3%), followed by rmtB (8,30.8%),and 7 CR-hvKP strains were found to carry both armA and rmtB (26.9%). All the clinical isolates were found to carry at least one carbapenemase gene,with KPC-2 (79.5%,31/39), NDM-1 (10.3%,4/39), and cocarrying KPC-2 and NDM-1 (10.3%,4/39). A total of 89.7% (35/39) isolates carried ESBL genes, including 61.5% (24/39) blaSHV-1 ,71.8% (28/39) blaTEM-1 and 89.7% (35/39) blaCTX-M-1 4. All except four isolates (89.7%,35/39) harbored PMQR genes,with qnrS (82.1%,32/39), aac(6’)-Ib-cr (79.5%,31/39), qnrB (2.6%,1/39).All the 16S rRNA methylase genes-positive CR-hvKP strains were firstly found to cocarry carbapenemase genes, ESBL genes and PMQR genes simultaneously. The most prevalent virulence genes were rmpA2 and entB (100%, 39/39),followed by silS (97.4%, 38/39), ybtS (94.9%, 37/39), iutA (92.3%, 36/39), kpn (92.3%, 36/39), rmpA (87.2%, 34/39), terW (84.6%, 33/39), aerobactin (23.1%, 9/39), repA (17.9%, 7/39), magA (10.3%, 4/39), kfuB C (10.3%, 4/39), w ca G (10.3%, 4/39), allS (10.3%, 4/39). Multilocus sequence typing (MLST) analysis assigned the 39 CR-hvKP isolates into 4 sequence types (STs), with ST11 encompassing 79.5% of the strains. Pulsed field gel electrophoresis (PFGE) typing showed that strains closely related by MLST clustered in major PFGE clusters, of which cluster A accounts for 31 ST11 isolates.The analysis of the transconjugants showed a high-level aminoglycoside resistance and a popular cotransfer of bla KPC-2 with the 16S rRNA methylase genes.Conclusions : 16S rRNA methylase genes are highly prevalent in CR-hvKP clinical isolates especially for ST11, it is therefore critical to continuously monitor the 16S rRNA methylase-producing CR-hvKP epidemiology and minimize potential risks from aminoglycoside -resistant CR-hvKP.
High Prevalence of 16s rRNA Methylase Genes Among Carbapenem-Resistant Hypervirulent Klebsiella pneumoniae Isolates in a Chinese Tertiary Hospital