Abstract
Background: Klebsiella pneumoniae is a common causative pathogen of nosocomial infections. The emergence of carbapenem-resistant hypervirulent K. pneumoniae (CR-hvKP) strains has further increased the threat posed by this bacterium. Here, we described an outbreak of 32 CR-hvKP isolates from the emergency intensive care unit (EICU) of a teaching hospital in China. Methods: From January 29, 2019 to March 11, 2019, 32 CRKp isolates were collected from 6 patients and their surrounding environment in EICU. Patient information including age, gender, length of EICU stay, diagnosis, treatment, and outcomes were obtained from electronic medical records. The isolates were identified using Vitek-MS system. The hypermucoviscosity phenotype was determined by the “string test”. Antimicrobial susceptibility testing was performed using VITEK 2 compact system, E-test or the broth microdilution method. All isolates were serotyped for K1, K2, K5, K20, K54, and K57 serotypes, antimicrobial resistance genes and twelve virulence-associated genes were screened using PCR and DNA sequencing. Multilocus sequence typing (MLST) and pulse-field gel electrophoresis (PFGE) were employed to characterize the genetic relationships among the CPKP isolates. The virulence capability of 11 CRKp isolates from 6 patients was evaluated through Galleria mellonella larva infection assay. Results: This outbreak involved 6 patients and lasted for 40 days. All 32 CR-hvKp isolates were obtained from 6 patients and their surrounding environment. PFGE showed that all 32 isolates belonged to one cluster, and MLST revealed that belonged to ST11. All isolates exhibited high resistance to β-lactam antibiotics, quinolones, and aminoglycosides. They were susceptible to ceftazidime/averbatan, tigecycline, and colistin. All 32 isolates harbored multiple resistance determinants, including blaKPC-2, blaSHV-11, blaTEM-1, rmtB, and qnrD. The serotype of all 32 isolates was K57 that was rarely reported. In the virulence gene analysis, all 32 isolates contained 6 virulence genes, namely, fimH, iucB, mrkD, rmpA, uge, and wabG. Infection assays demonstrated high mortality in the Galleria mellonella model. Following measures implemented by the hospital, the outbreak was controlled. The mortality rate was 83.3%.Conclusions: The epidemiology of CR-hvKP should be monitored closely to detect early indications of this emerging public health threat.
Control of carbapenem-resistant Acinetobacter baumannii outbreak in an intensive care unit of a teaching hospital in Southern Italy