Dataset Information

Use of multilocus variable number of tandem repeats analysis genotyping to determine the role of asymptomatic carriers in Clostridium difficile transmission.

ABSTRACT:

Background

Previous studies have suggested that asymptomatic carriers of toxigenic Clostridium difficile are a source of hospital-associated (HA) infections. Multilocus variable number of tandem repeats analysis (MLVA) is a highly discriminatory molecular subtyping tool that helps to determine possible transmission sources.

Methods

Clostridium difficile isolates were recovered from perirectal swabs collected for vancomycin-resistant Enterococcus (VRE) surveillance as well as from clinical C. difficile toxin-positive stool samples from July to November 2009 at the University of Pittsburgh Medical Center Presbyterian (UPMC). MLVA was performed to determine the genetic relationships between isolates from asymptomatic carriers and patients with HA C. difficile infection (HA-CDI). Asymptomatic carriage and HA-CDI isolates were considered to be associated if the carriage isolate was collected before the HA-CDI isolate and if the MLVA genotypes had a summed tandem-repeat difference of ? 2.

Results

Of 3006 patients screened, 314 (10.4%) were positive for toxigenic C. difficile, of whom 226 (7.5%) were detected only by VRE surveillance cultures. Of 56 incident cases of CDI classified as HA at UPMC during the study with available isolates, 17 (30%) cases were associated with CDI patients, whereas 16 (29%) cases were associated with carriers. Transmission events from prior bed occupants with CDI (n = 2) or carriers (n = 2) were identified in 4 of 56 cases.

Conclusions

In our hospital with an established infection control program designed to contain transmission from symptomatic CDI patients, asymptomatic carriers appear to have played an important role in transmission. Identification and isolation of carriers may be necessary to further reduce transmission of C. difficile in such settings.

SUBMITTER: Curry SR

PROVIDER: S-EPMC3783061 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature

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Publications

Use of multilocus variable number of tandem repeats analysis genotyping to determine the role of asymptomatic carriers in Clostridium difficile transmission.

Curry Scott R SR Muto Carlene A CA Schlackman Jessica L JL Pasculle A William AW Shutt Kathleen A KA Marsh Jane W JW Harrison Lee H LH

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 20130723 8

<h4>Background</h4>Previous studies have suggested that asymptomatic carriers of toxigenic Clostridium difficile are a source of hospital-associated (HA) infections. Multilocus variable number of tandem repeats analysis (MLVA) is a highly discriminatory molecular subtyping tool that helps to determine possible transmission sources.<h4>Methods</h4>Clostridium difficile isolates were recovered from perirectal swabs collected for vancomycin-resistant Enterococcus (VRE) surveillance as well as from ...[more]

PMID: 23881150

Similar Datasets

Project description:No study to date has compared multilocus variable-number tandem-repeat analysis (MLVA) and whole-genome sequencing (WGS) in an investigation of the transmission of Clostridium difficile infection. Isolates from 61 adults with ongoing and/or recurrent C. difficile infections and 17 asymptomatic carriage episodes in children (201 samples), as well as from 61 suspected outbreaks affecting 2 to 41 patients in 31 hospitals in the United Kingdom (300 samples), underwent 7-locus MLVA and WGS in parallel. When the first and last samples from the same individual taken for a median (interquartile range [IQR]) of 63 days (43 to 105 days) apart were compared, the estimated rates of the evolution of single nucleotide variants (SNVs), summed tandem-repeat differences (STRDs), and locus variants (LVs) were 0.79 (95% confidence interval [CI], 0.00 to 1.75), 1.63 (95% CI, 0.00 to 3.59), and 1.21 (95% CI, 0.00 to 2.67)/called genome/year, respectively. Differences of >2 SNVs and >10 STRDs have been used to exclude direct case-to-case transmission. With the first serial sample per individual being used to assess discriminatory power, across all pairs of samples sharing a PCR ribotype, 192/283 (68%) differed by >10 STRDs and 217/283 (77%) by >2 SNVs. Among all pairs of cases from the same suspected outbreak, 1,190/1,488 (80%) pairs had concordant results using >2 SNVs and >10 STRDs to exclude transmission. For the discordant pairs, 229 (15%) had ?2 SNVs but ?10 STRDs, and 69 (5%) had ?2 SNVs but ?10 STRDs. Discordant pairs had higher numbers of LVs than concordant pairs, supporting the more diverse measure in each type of discordant pair. Conclusions on whether the potential outbreaks were confirmed were concordant in 58/61 (95%) investigations. Overall findings using MLVA and WGS were very similar despite the fact that they analyzed different parts of the bacterial genome. With improvements in WGS technology, it is likely that MLVA locus data will be available from WGS in the near future.

Dataset Information

Use of multilocus variable number of tandem repeats analysis genotyping to determine the role of asymptomatic carriers in Clostridium difficile transmission.

Background

Methods

Results

Conclusions

Publications

Use of multilocus variable number of tandem repeats analysis genotyping to determine the role of asymptomatic carriers in Clostridium difficile transmission.

Similar Datasets

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