High prevalence of colistin heteroresistance in specific species and lineages of Enterobacter cloacae complex derived from human clinical specimens

Annals of Clinical Microbiology and Antimicrobials

Research

Satoshi Takahashi¹  Kotaro Aoki²  Shin-ichi Yokota³  Soh Yamamoto³  Noriko Ogasawara³  Shota Fukuzawa⁴  Toyotaka Sato⁵  Yasuhiko Suzuki⁶  Chie Nakajima⁶  Motohiro Horiuchi⁷ 

[1] Department of Infection Control and Laboratory Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan;Division of Laboratory Medicine, Sapporo Medical University Hospital, Sapporo, Japan;Department of Microbiology and Infectious Diseases, Toho University School of Medicine, Tokyo, Japan;Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan;Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan;Clinical Laboratory, National Hospital Organization Hokkaido Cancer Center, Sapporo, Japan;Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan;Laboratory of Veterinary Hygiene, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan;Graduate School of Infectious Diseases, Hokkaido University, Sapporo, Japan;One Health Research Center, Hokkaido University, Sapporo, Japan;Division of Bioresources, Hokkaido University International Institute for Zoonosis Control, Sapporo, Japan;International Collaboration Unit, Hokkaido University, International Institute for Zoonosis Control, Sapporo, Japan;Institute for Vaccine Research and Development (HU-IVReD), Hokkaido University, Sapporo, Japan;Laboratory of Veterinary Hygiene, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan;Graduate School of Infectious Diseases, Hokkaido University, Sapporo, Japan;One Health Research Center, Hokkaido University, Sapporo, Japan;

关键词: Enterobacter cloacae;    Colistin;    Heteroresistance;    arnT;    PhoPQ;    Average nucleotide identity (ANI);   

DOI  :  10.1186/s12941-023-00610-1

 received in 2023-04-14, accepted in 2023-07-05,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundColistin (CST) is a last-line drug for multidrug-resistant Gram-negative bacterial infections. CST-heteroresistant Enterobacter cloacae complex (ECC) has been isolated. However, integrated analysis of epidemiology and resistance mechanisms based on the complete ECC species identification has not been performed.MethodsClinical isolates identified as “E. cloacae complex” by MALDI-TOF MS Biotyper Compass in a university hospital in Japan were analyzed. Minimum inhibitory concentrations of CST were determined by the broth microdilution method. The population analysis profiling (PAP) was performed for detecting the heteroresistant phenotype. The heat shock protein 60 (hsp60) cluster was determined from its partial nucleotide sequence. From the data of whole-genome sequencing, average nucleotide identity (ANI) for determining ECC species, multilocus sequence type, core genome single-nucleotide-polymorphism-based phylogenetic analysis were performed. phoPQ-, eptA-, and arnT-deleted mutants were established to evaluate the mechanism underlying colistin heteroresistance. The arnT mRNA expression levels were determined by reverse transcription quantitative PCR.ResultsThirty-eight CST-resistant isolates, all of which exhibited the heteroresistant phenotype by PAP, were found from 138 ECC clinical isolates (27.5%). The prevalence of CST-resistant isolates did not significantly differ among the origin of specimens (29.0%, 27.8%, and 20.2% for respiratory, urine, and blood specimens, respectively). hsp60 clusters, core genome phylogeny, and ANI revealed that the CST-heteroresistant isolates were found in all or most of Enterobacter roggenkampii (hsp60 cluster IV), Enterobacter kobei (cluster II), Enterobacter chuandaensis (clusters III and IX), and Enterobacter cloacae subspecies (clusters XI and XII). No heteroresistant isolates were found in Enterobacter hormaechei subspecies (clusters VIII, VI, and III) and Enterobacter ludwigii (cluster V). CST-induced mRNA upregulation of arnT, which encodes 4-amino-4-deoxy-l-arabinose transferase, was observed in the CST-heteroresistant isolates, and it is mediated by phoPQ pathway. Isolates possessing mcr-9 and mcr-10 (3.6% and 5.6% of total ECC isolates, respectively) exhibited similar CST susceptibility and PAP compared with mcr-negative isolates.ConclusionsSignificant prevalence (approximately 28%) of CST heteroresistance is observed in ECC clinical isolates, and they are accumulated in specific species and lineages. Heteroresistance is occurred by upregulation of arnT mRNA induced by CST. Acquisition of mcr genes contributes less to CST resistance in ECC.

【 授权许可】

CC BY   
© The Author(s) 2023

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