Clonal Dissemination of Clinical Carbapenem-Resistant Klebsiella pneumoniae Isolates Carrying fosA3 and bla KPC -2 Coharboring Plasmids in Shandong, China

Treatment strategies of infection by carbapenem-resistant (CRKP) are limited. Fosfomycin, a broad-spectrum antibiotic, has attracted renewed interest in combination therapy to fight infections. However, reports on fosfomycin-resistant are increasing. Among the 57 CRKP strains, 40 (70.2%) were resistant to fosfomycin. Thus, whole-genome sequencing and bioinformatics analysis were conducted to reveal molecular characteristics of fosfomycin-resistant . Twenty-three isolates coharbored and , with carbapenemase (KPC)-producing ST11-KL64-wzi64-O2 ( = 13) and ST11-KL47-wzi209-OL101 ( = 8), the predominating clonal groups, while was not detected in isolates carrying class B carbapenemase genes. Twenty-two (out of 26) ST11-KL64 strains were positive for , of which 12 carried . Four of the 23 -positive isolates could successfully transfer their fosfomycin-resistant determinants to J53Azi . All four strains belonged to ST11-KL47 with the same pulsed-field gel electrophoresis profile, and their transconjugants acquired fosfomycin, carbapenem, and aminoglycoside resistance. A 127-kb conjugative pCT-KPC-like hybrid plasmid (pJNKPN52_KPC_fosA) coharboring , , , , , and was identified. ST11-KL64 and ST11-KL47 , with higher resistance and virulence, should be critically monitored to prevent the future dissemination of resistance.