Unique Clindamycin-Resistant Clostridioides difficile Strain Related to Fluoroquinolone-Resistant Epidemic BI/RT027 Strain.

Andrew M Skinner,Dale N Gerding,Susan P Sambol,Farida Siddiqui,Curtis J Donskey,Laurica Petrella,Christopher A Gulvik,Stuart Johnson

doi:10.3201/eid2602.181965

Abstract

During a surveillance study of patients in a long-term care facility and the affiliated acute care hospital in the United States, we identified a Clostridioides difficile strain related to the epidemic PCR ribotype (RT) 027 strain associated with hospital outbreaks of severe disease. Fifteen patients were infected with this strain, characterized as restriction endonuclease analysis group DQ and RT591. Like RT027, DQ/RT591 contained genes for toxin B and binary toxin CDT and a tcdC gene of identical sequence. Whole-genome sequencing and multilocus sequence typing showed that DQ/RT591 is a member of the same multilocus sequence typing clade 2 as RT027 but in a separate cluster. DQ/RT591 produced a similar cytopathic effect as RT027 but showed delayed toxin production in vitro. DQ/RT591 was susceptible to moxifloxacin but highly resistant to clindamycin. Continued surveillance is warranted for this clindamycin-resistant strain that is related to the fluoroquinolone-resistant epidemic RT027 strain.

Highlights

During a surveillance study of patients in a long-term care facility and the affiliated acute care hospital in the United States, we identified a Clostridioides difficile strain related to the epidemic PCR ribotype (RT) 027 strain associated with hospital outbreaks of severe disease
16 (19%) of the isolates from 15 Cleveland patients were identified as restriction endonuclease analysis (REA) strain DQ, even though the corresponding Xpert C. difficile EPI assay results indicated the presence of the NAP1 strain (i.e., REA group BI)
During a surveillance study of C. difficile in asymptomatic long-term care facilities (LTCFs) patients and symptomatic patients in the affiliated acute care hospitals at 2 Veteran Affairs (VA) facilities [16], we detected a clonal outbreak of a newly recognized C. difficile strain at the Cleveland facility. This strain, identified as REA group DQ, ribotype 591, is closely related to the BI/RT027 strain, and a commercial PCR erroneously identified it as the epidemic NAP1 strain (i.e., BI/RT027)

Summary

Introduction

During a surveillance study of patients in a long-term care facility and the affiliated acute care hospital in the United States, we identified a Clostridioides difficile strain related to the epidemic PCR ribotype (RT) 027 strain associated with hospital outbreaks of severe disease. The pathogenicity locus of BI/RT027 includes a characteristic 18-bp deletion and a single-base deletion at position 117 of the tcdC gene [4] These mutations result in a truncated TcdC protein that is rendered nonfunctional, leading to a lack of regulation of the tcdA and tcdB genes and potentially increased toxin A and B production [4]. During the past 10 years, non-RT027 strains have emerged that test positive by this assay because they have the same or similar gene targets [12,13] Several of these non-RT027 strains have been associated with increased numbers of illnesses and deaths, suggesting that the gene targets for this assay may be related to increased virulence [12,13,14]

Methods

Results

Conclusion