Predominance of Clostridioides difficile PCR ribotype 181 in northern Greece, 2016-2019

Antimicrobial susceptibility in Clostridioides difficile varies according to European region and isolate source

Objectives

Clostridioides difficile epidemiology is evolving with country-associated emerging and resistant ribotypes (RT). Antimicrobial susceptibility testing of C. difficile isolated from clinical and animal samples collected across Europe in 2018 was performed to provide antimicrobial resistance data and according to C. difficile RTs and source.

Methods

Samples were cultured for C. difficile and isolates PCR ribotyped. Metronidazole, vancomycin, fidaxomicin, moxifloxacin, clindamycin, imipenem, tigecycline, linezolid, rifampicin and meropenem minimum inhibitory concentrations (MICs) for 280 clinical and 126 animal isolates were determined by Wilkins-Chalgren agar dilution.

Results

Fidaxomicin was the most active antimicrobial (all isolates geometric mean MIC = 0.03 mg/L) with no evidence of reduced susceptibility. Metronidazole MICs were elevated among RT027 (1.87 mg/L) and RT181 clinical isolates (1.03 mg/L). RT027 and RT181 had elevated geometric mean moxifloxacin MICs (14.49 mg/L, 16.88 mg/L); clindamycin (7.5 mg/L, 9.1 mg/L) and rifampicin (0.6 mg/L, 21.5 mg/L). Five isolates (RT002, RT010 and RT016) were metronidazole resistant (MIC = 8 mg/L) and 10 (RT027; RT198) had intermediate resistance (4 mg/L). Metronidazole MICs were not elevated in animal isolates. Increased geometric mean vancomycin MICs were observed among RT078, mostly isolated from animals, but there was no resistance (MIC ≥ 4 mg/L). Clinical and animal isolates of multiple RTs showed resistance to moxifloxacin and clindamycin. No resistance to imipenem or meropenem was observed.

Conclusion

Increased antimicrobial resistance was detected in eastern Europe and mostly associated with RT027 and related emerging RT181, while clinical isolates from northern and western Europe had the lowest general levels of resistance.

Clostridioides difficile infection epidemiology during the COVID-19 pandemic in Greece

Aim: The aim was to highlight the incidence and epidemiology of C. difficile infections (CDI) in a tertiary Greek hospital during the COVID-19 pandemic. Methods: A single-center prospective observational cohort study was conducted (October 2021 until April 2022). 125 C. difficile isolates were cultured from hospitalized patients stool samples and screened by PCR for toxin A (tcdA), toxin B (tcdB), binary toxin (cdtA and cdtB) genes and the regulating gene of tcdC. Results: The incidence of CDI increased to 13.1 infections per 10,000 bed days. The most common PCR ribotypes identified included hypervirulent RT027-related RT181 (73.6%), presumably hypervirulent RT126 (8.0%) and toxin A negative RT017 (7.2%). Conclusion: Although the incidence of CDI increased significantly, the CDI epidemiology remained stable.

Toxin genotypes, antibiotic resistance and their correlations in Clostridioides difficile isolated from hospitals in Xi'an, China

BACKGROUND

Clostridioides difficile is the main pathogen of antimicrobial-associated diarrhoea and health care facility-associated infectious diarrhoea. This study aimed to investigate the prevalence, toxin genotypes, and antibiotic resistance of C. difficile among hospitalized patients in Xi'an, China.

RESULTS

We isolated and cultured 156 strains of C. difficile, representing 12.67% of the 1231 inpatient stool samples collected. Among the isolates, tcdA + B + strains were predominant, accounting for 78.2% (122/156), followed by 27 tcdA-B + strains (27/156, 17.3%) and 6 binary toxin gene-positive strains. The positive rates of three regulatory genes, tcdC, tcdR, and tcdE, were 89.1% (139/156), 96.8% (151/156), and 100%, respectively. All isolates were sensitive to metronidazole, and the resistance rates to clindamycin and cephalosporins were also high. Six strains were found to be resistant to vancomycin.

CONCLUSION

Currently, the prevalence rate of C. difficile infection (CDI) in Xi'an is 12.67% (156/1231), with the major toxin genotype of the isolates being tcdA + tcdB + cdtA-/B-. Metronidazole and vancomycin were still effective drugs for the treatment of CDI, but we should pay attention to antibiotic management and epidemiological surveillance of CDI.

Ribotypes and New Virulent Strains Across Europe

Clostridioides (formerly Clostridium) difficile is a major bacterial cause of post-antibiotic diarrhoea. The epidemiology of C. difficile infections (CDIs) has dramatically changed since the early 2000s, with an increasing incidence and severity across Europe. This trend is partly due to the emergence and rapid worldwide spread of the hypervirulent and epidemic PCR ribotype 027. Profiles of patients with CDI have also evolved, with description of community-acquired (CA) infections in patients with no traditional risk factors for CDI. However, epidemiological studies indicated that some European countries have successfully controlled the dissemination of the 027 clone whereas other countries reported the emergence of other virulent or unusual strains. The aims of this review are to summarize the current European CDI epidemiology and to describe the new virulent C. difficile strains circulating in Europe, as well as other potential emerging strains described elsewhere. Standardized typing methods and surveillance programmes are mandatory for a better understanding and monitoring of CDI in Europe.

Antibiotic Resistances of Clostridioides difficile

The rapid evolution of antibiotic resistance in Clostridioides difficile and the consequent effects on prevention and treatment of C. difficile infections (CDIs) are a matter of concern for public health. Antibiotic resistance plays an important role in driving C. difficile epidemiology. Emergence of new types is often associated with the emergence of new resistances, and most of the epidemic C. difficile clinical isolates is currently resistant to multiple antibiotics. In particular, it is to worth to note the recent identification of strains with reduced susceptibility to the first-line antibiotics for CDI treatment and/or for relapsing infections. Antibiotic resistance in C. difficile has a multifactorial nature. Acquisition of genetic elements and alterations of the antibiotic target sites, as well as other factors, such as variations in the metabolic pathways or biofilm production, contribute to the survival of this pathogen in the presence of antibiotics. Different transfer mechanisms facilitate the spread of mobile elements among C. difficile strains and between C. difficile and other species. Furthermore, data indicate that both genetic elements and alterations in the antibiotic targets can be maintained in C. difficile regardless of the burden imposed on fitness, and therefore resistances may persist in C. difficile population in absence of antibiotic selective pressure.

Clostridioides difficile, a New “Superbug”

Clostridioides difficile is a Gram-positive, spore-forming, anaerobic bacterium. The clinical features of C. difficile infections (CDIs) can vary, ranging from the asymptomatic carriage and mild self-limiting diarrhoea to severe and sometimes fatal pseudomembranous colitis. C. difficile infections (CDIs) are associated with disruption of the gut microbiota caused by antimicrobial agents. The infections are predominantly hospital-acquired, but in the last decades, the CDI patterns have changed. Their prevalence increased, and the proportion of community-acquired CDIs has also increased. This can be associated with the appearance of hypervirulent epidemic isolates of ribotype 027. The COVID-19 pandemic and the associated antibiotic overuse could additionally change the patterns of infections. Treatment of CDIs is a challenge, with only three appropriate antibiotics for use. The wide distribution of C. difficile spores in hospital environments, chronic persistence in some individuals, especially children, and the recent detection of C. difficile in domestic pets can furthermore worsen the situation. “Superbugs” are microorganisms that are both highly virulent and resistant to antibiotics. The aim of this review article is to characterise C. difficile as a new member of the “superbug” family. Due to its worldwide spread, the lack of many treatment options and the high rates of both recurrence and mortality, C. difficile has emerged as a major concern for the healthcare system.