Antibiotic Resistances and Molecular Characteristics of Clostridioides difficile in ICUs in a Teaching Hospital From Central South China

Characterization of community-acquired Clostridioides difficile strains in Israel, 2020-2022

Background

The prevalence of community-acquired Clostridioides difficile infection (CA-CDI) has been rising, due to changes in antibiotics prescribing practices, emergence of hypervirulent strains and improved diagnostics. This study explored CA-CDI epidemiology by examining strain diversity and virulence factors of CA-CDI isolates collected across several geographical regions in Israel.

Methods

Stool samples of 126 CA-CDI patients were subjected to PCR and an immunoassay to identify toxin genes and proteins, respectively. Toxin loci PaLoc and PaCdt were detected by whole-genome sequencing (WGS). Biofilm production was assessed by crystal violet-based assay. Minimum inhibitory concentration was determined using the Etest technique or agar dilution. WGS and multi-locus sequence typing (MLST) were used to classify strains and investigate genetic diversity.

Results

Sequence types (ST) 2 (17, 13.5%), ST42 (13, 10.3%), ST104 (10, 8%) and ST11 (9, 7.1%) were the most common. All (117, 92.8%) but ST11 belonged to Clade 1. No associations were found between ST and gender, geographic area or antibiotic susceptibility. Although all strains harbored toxins genes, 34 (27%) produced toxin A only, and 54 (42.9%) strains produced toxin B only; 38 (30.2%) produced both toxins. Most isolates were biofilm-producers (118, 93.6%), primarily weak producers (83/118, 70.3%). ST was significantly associated with both biofilm and toxin production.

Conclusion

C. difficile isolates in Israel community exhibit high ST diversity, with no dominant strain. Other factors may influence the clinical outcomes of CDI such as toxin production, antibiotic resistance and biofilm production. Further studies are needed to better understand the dynamics and influence of these factors on CA-CDI.

Update on Commonly Used Molecular Typing Methods for Clostridioides difficile

This review aims to provide a comprehensive overview of the significant Clostridioides difficile molecular typing techniques currently employed in research and medical communities. The main objectives of this review are to describe the key molecular typing methods utilized in C. difficile studies and to highlight the epidemiological characteristics of the most prevalent strains on a global scale. Geographically distinct regions exhibit distinct strain types of C. difficile, with notable concordance observed among various typing methodologies. The advantages that next-generation sequencing (NGS) offers has changed epidemiology research, enabling high-resolution genomic analyses of this pathogen. NGS platforms offer an unprecedented opportunity to explore the genetic intricacies and evolutionary trajectories of C. difficile strains. It is relevant to acknowledge that novel routes of transmission are continually being unveiled and warrant further investigation, particularly in the context of zoonotic implications and environmental contamination.

Evaluation of Two Rapid Diagnostic Clostridioides difficile Infection Tests in a Chinese Hospital: A Real-world Analysis

Background: Accurate diagnosis is essential for optimal prevention and treatment of Clostridioides difficile infection (CDI), and various diagnostic methods must be evaluated. Objectives: We aimed to evaluate and compare the performance of VIDAS C. difficile, C. DIFF QUIK CHEK COMPLETE (QCC), and toxigenic culture (TC) tests for diagnosing CDI and further determine the relationships between clinical factors and the toxin status of patients. Methods: Stool samples were randomly selected for VIDAS or QCC testing according to the manufacturer’s instructions between May 2017 and May 2021, and their performance was compared with that of TC. Clinical information was obtained from the hospital’s electronic medical records. Results: Among 10,897 samples tested, 6,435 and 4,462 samples were assigned for VIDAS and QCC tests, respectively. A total of 9.1% (996/10,897) of the samples were positive for TC. The sensitivity, specificity, positive predictive value, and negative predictive value were 36.6%, 98.6%, 72.1%, and 87.6% for VIDAS toxins A and B testing and 31.6%, 98.2%, 64.0%, and 87.8% for QCC toxin testing, respectively. Our results showed that the clinical data of the patients with positive and detectable toxins were not significantly different. Conclusions: The VIDAS and QCC tests provide rapid screening assays for the laboratory diagnosis of CDI. However, a more specific test to detect free toxins is required to confirm the diagnosis for glutamate dehydrogenase (GDH)-positive and toxin-negative samples. The clinical characteristics and outcomes of this cohort were similar, regardless of the results of toxins A and B testing.