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

Risk factors for Clostridioides difficile infection caused by ribotype 027 strains in the Veterans Affairs Healthcare System: a matched case-control study

BACKGROUND

In case-control studies, a variety of factors have been associated with Clostridioides difficile infection (CDI) due to the epidemic ribotype 027 strain. However, many studies have been limited due to small sample size and inclusion of only one facility.

METHODS

Using a nationwide cohort of hospitalized patients in the Veterans Affairs (VA) Healthcare System, we conducted a retrospective, 1:3 matched case-control study of patients with CDI due to the ribotype 027 strain versus non-027 strains from October 1, 2008, to September 30, 2020. Controls were matched to cases by health care facility and year of diagnosis. Multivariate logistic regression was used to identify risk factors for CDI due to the 027 strain.

RESULTS

A total of 3,353 cases were matched to 10,059 controls in 84 VA facilities. CDI due to the ribotype 027 strain was independently associated with prior macrolide or fluoroquinolone exposure, decreased functional capability, methicillin-resistant Staphylococcus aureus nasal colonization, age >65 years, white blood cell count >11,000 cells/mm3, and serum albumin < 3.5 g/dl.

CONCLUSION

Antimicrobial stewardship interventions focused on fluoroquinolones and macrolides could be beneficial in reducing the risk for infection due to the ribotype 027 C. difficile strain. Several other factors could potentially be used to identify patients at increased risk for CDI due to the ribotype 027 strain, but further studies are needed to assess their utility in clinical settings.

Predominance of FQR1 NAP1/RT027 Clostridioides difficile Among Mexican Children and Adult Patients, and its Resistance to Eleven Antibiotics

AIMS

Clostridioides difficile is a major cause of antibiotic-associated diarrhea. This study investigated the diversity, clonality, and antimicrobial resistance of C. difficile isolates from Mexican children and adults with diarrhea.

METHODS

Between 2014 and 2016, we isolated 37 C. difficile strains in three hospitals in Mexico City. C. difficile strains were typed by PCR-ribotyping and pulsed-field gel electrophoresis (PFGE). Antimicrobial susceptibility to eleven antibiotics was determined. Whole-genome sequencing (WGS) was used to investigate the presence of antimicrobial resistance genes (ARG) and perform a pangenome analysis of 53 genomes from Mexico and 137 publicly available C. difficile genomes.

RESULTS

Toxigenic strains comprised six isolates from children and 31 from adults. While NAP1/RT027 isolates were found in three children, they were predominant in adults (n = 31, 90.3 %) and showed the 1058 and 008 PFGE macrorestriction patterns. All isolates were susceptible to vancomycin and metronidazole but resistant to ciprofloxacin, and over 90 % of the isolates were resistant to linezolid and carried cfr(E). The pangenome of these isolates contained 4,852 genes, of which 3,455 (81.2 %) were categorized as core genes and 801 (18.8 %) as accessory genes. In addition, our isolates demonstrated a close relationship with strains from the United States, Canada, and France.

CONCLUSIONS

Our work provides, for the first time, genomic insights into C. difficile strains present in Mexico. In our hospital setting, the predominant strains were primarily NAP1/RT027 and exhibited resistance to linezolid, a pattern observed in both pediatric and adult populations. This unique combination of characteristics has not been previously reported in Latin America.

Genomic analysis reveals the presence of hypervirulent and fluoroquinolone-resistant Clostridioides difficile in farmed mussels (Mytilus galloprovincialis) in Slovenia

Clostridioides difficile is one of the leading causes of antibiotic-associated diarrhea. In this study, we characterized 76C. difficile isolates, obtained from three Mediterranean mussel (Mytilus galloprovincialis) farms in Slovenia from November 2014 to October 2015 (sampling period 1) and from January to December 2021 (sampling period 2). The overall isolation rate of C. difficile from all the examined mussels was 59.8 %. A statistically significant trend of seasonal variation was observed, with a higher isolation rate in the colder months of the year (87.9 %; sea temperature ≤ 15 °C) compared with the warmer months (31.8 %; sea temperature > 15 °C). Whole-genome sequencing (WGS) revealed that the isolates belonged to 31 different sequence types (STs), which were associated with three clades (1, 4, and 5) and two cryptic clades (C-II and C-III). Five isolates, which belonged to ST11 (clade 5), harbored all the main toxin genes (A+B+CDT+) and chromosomal mutations conferring fluoroquinolone resistance. Core genome multilocus sequence typing (cgMLST) revealed four clusters of 2-3 isolates, three of which included isolates from different farms, suggesting that clonal C. difficile strains are circulating among the Slovenian mussel farms. The results highlight the presence of hypervirulent strains in mussels; therefore, at-risk population groups should be alerted to the risks associated with consuming shellfish.

Epidemiology of Clostridioides difficile infection at one hospital 10 years after an outbreak of the epidemic C. difficile strain BI/027: changing strain prevalence, antimicrobial susceptibilities, and patient antibiotic exposures

In contrast to the epidemiology 10 years earlier at our hospital when the epidemic restriction endonuclease analysis (REA) group strain BI accounted for 72% of Clostridioides difficile isolates recovered from first-episode C. difficile infection (CDI) cases, BI represented 19% of first-episode CDI isolates in 2013-2015. Two additional REA group strains accounted for 31% of isolates (Y, 16%; DH, 12%). High-level resistance to fluoroquinolones and azithromycin was more common among BI isolates than among DH, Y, and non-BI/DH/Y isolates. Multivariable analysis revealed that BI cases were 2.47 times more likely to be associated with fluoroquinolone exposure compared to non-BI cases (95% confidence interval [CI]: 1.12-5.46). In addition, the odds of developing a CDI after third- or fourth-generation cephalosporin exposure was 2.83 times for DH cases than for non-DH cases (95% CI: 1.06-7.54). Fluoroquinolone use in the hospital decreased from 2005 to 2015 from a peak of 113 to a low of 56 antimicrobial days/1,000 patient days. In contrast, cephalosporin use increased from 42 to 81 antimicrobial days/1,000 patient days. These changes correlated with a decrease in geometric mean MIC for ciprofloxacin (61.03 to 42.65 mg/L, P = 0.02) and an increase in geometric mean MIC for ceftriaxone (40.87 to 86.14 mg/L, P < 0.01) among BI isolates. The BI strain remained resistant to fluoroquinolones, but an overall decrease in fluoroquinolone use and increase in cephalosporin use were associated with a decrease in the prevalence of BI, an increased diversity of C. difficile strain types, and the emergence of strains DH and Y.

Make It Less difficile: Understanding Genetic Evolution and Global Spread of Clostridioides difficile

Clostridioides difficile is an obligate anaerobic pathogen among the most common causes of healthcare-associated infections. It poses a global threat due to the clinical outcomes of infection and resistance to antibiotics recommended by international guidelines for its eradication. In particular, C. difficile infection can lead to fulminant colitis associated with shock, hypotension, megacolon, and, in severe cases, death. It is therefore of the utmost urgency to fully characterize this pathogen and better understand its spread, in order to reduce infection rates and improve therapy success. This review aims to provide a state-of-the-art overview of the genetic variation of C. difficile, with particular regard to pathogenic genes and the correlation with clinical issues of its infection. We also summarize the current typing techniques and, based on them, the global distribution of the most common ribotypes. Finally, we discuss genomic surveillance actions and new genetic engineering strategies as future perspectives to make it less difficile.

Microbiological features, epidemiology, and clinical presentation of Clostridioidesdifficile strains from MLST Clade 2: A narrative review

Clostridioides difficile is an emerging One Health pathogen and a common etiologic agent of diarrhea, both in healthcare settings and the community. This bacterial species is highly diverse, and its global population has been classified in eight clades by multilocus sequence typing (MLST). The C. difficile MLST Clade 2 includes the NAP1/RT027/ST01 strain, which is highly recognized due to its epidemicity and association with severe disease presentation and mortality. By contrast, the remaining 83 sequence types (STs) that compose this clade have received much less attention. In response to this shortcoming, we reviewed articles published in English between 1999 and 2020 and collected information for 27 Clade 2 STs, with an emphasis on STs 01, 67, 41 and 188/231/365. Our analysis provides evidence of large phenotypic differences that preclude support of the rather widespread notion that ST01 and Clade 2 strains are "hypervirulent". Moreover, it revealed a profound lack of (meta)data for nearly 70% of the Clade 2 STs that have been identified in surveillance efforts. Targeted studies aiming to relate wet-lab and bioinformatics results to patient and clinical parameters should be performed to gain a more in-depth insight into the biology of this intriguing group of C. difficile isolates.

An Outbreak of Clostridium (Clostridioides) difficile Infections within an Acute and Long-Term Care Wards Due to Moxifloxacin-Resistant PCR Ribotype 176 Genotyped as PCR Ribotype 027 by a Commercial Assay

We aimed to characterize Clostridioides difficile isolates cultured during a six-month single-center study from stool samples of patients with C. difficile infection (CDI) genotyped by the Xpert^®C. difficile/Epi assay by polymerase chain reaction (PCR) ribotyping, toxin genes’ detection and multi-locus variable number tandem repeats analysis (MLVA). The susceptibility to metronidazole, vancomycin and moxifloxacin was determined by agar dilution. In addition, the presence of Thr82Ile in the GyrA and a single nucleotide deletion at position (Δ117) in the tcdC gene were investigated. Between January 1 and June 30, 2016, of 114 CDIs, 75 cases were genotyped as presumptive PCR ribotype (RT) 027 infections using a commercial assay. C. difficile isolates cultured from presumptive RT027 stool samples belonged to RT176. These isolates carried genes for toxin A (tcdA), B (tcdB), binary (cdtA/B) and had Δ117 in the tcdC gene. Using MLVA, the 71/75 isolates clustered into two clonal complexes (CCs). Of these, 39 isolates (54.9%) were from patients hospitalized in acute care and 32 isolates (45.1%) were isolated from patients hospitalized in the long-term care department. All isolates were susceptible to metronidazole and vancomycin, and 105 isolates were resistant to moxifloxacin (92%) carrying Thr83Ile in the GyrA. An outbreak of RT176 CDIs, suspected as RT027, was recognized in a Slovakian hospital. In order to monitor the emergence and spread of RT027-variants, the identification of a presumptive RT027 CDI should be confirmed at a strain level by PCR ribotyping.