Antibiotic Resistance Profile of RT 027/176 Versus Other Clostridioides difficile Isolates in Silesia, Southern Poland

Molecular Epidemiology of Clostridioides difficile Infections in Patients Hospitalized in 2017-2019 at the Central Teaching Hospital of Medical University of Lodz, Central Poland

Background/Objectives:Clostridioides difficile infection (CDI) represents a significant public health challenge globally, driven by its increasing prevalence, hypervirulent strains like ribotype 027 (RT027), and growing antibiotic resistance. This study aimed to evaluate the prevalence of RT027 and analyze molecular markers of vancomycin and metronidazole resistance in stool samples from CDI patients hospitalized in Poland between 2017 and 2019. Methods: A total of 200 stool samples from confirmed CDI cases were analyzed for the presence of RT027, vanA (vancomycin resistance), and nim (metronidazole resistance) genes. DNA was extracted, and a polymerase chain reaction (PCR) was conducted using specific primers. Statistical associations between RT027 and resistance genes were evaluated using chi-square tests and logistic regression. Results: RT027 was detected in 14% of samples. The vanA gene, indicative of vancomycin resistance, was found in 52.5% of samples, while the nim gene, associated with metronidazole resistance, was present in 1.5% of cases. Co-occurrence of RT027 with vanA was not statistically significant. The study revealed no significant association between RT027 and vanA. Also, no significant association was observed between RT027 and nim due to the latter's low prevalence. Conclusions: This study highlights a concerning prevalence of vanA among CDI cases, indicating widespread vancomycin resistance and challenging current treatment guidelines. While RT027 prevalence was moderate, no significant associations with vancomycin or metronidazole resistance were observed. These findings emphasize the need for molecular surveillance and improved antimicrobial stewardship to manage CDI effectively.

The Use of Gel Electrophoresis to Separate Multiplex Polymerase Chain Reaction Amplicons Allows for the Easy Identification and Assessment of the Spread of Toxigenic Clostridioides difficile Strains

Clostridioides difficile is a common etiological factor of hospital infections, which, in extreme cases, can lead to the death of patients. Most strains belonging to this bacterium species synthesize very dangerous toxins: toxin A (TcdA) and B (TcdB) and binary toxin (CDT). The aim of this study was to assess the suitability of agarose gel electrophoresis separation of multiplex PCR amplicons to investigate the toxinogenic potential of C. difficile strains. Additionally, the frequency of C. difficile toxin genes and the genotypes of toxin-producing strains were determined. Ninety-nine C. difficile strains were used in the detection of the presence of genes encoding all of these toxins using the multiplex PCR method. In 85 (85.9%) strains, the presence of tcdA genes encoding enterotoxin A was detected. In turn, in 66 (66.7%) isolates, the gene encoding toxin B (tcdB) was present. The lowest number of strains tested was positive for genes encoding a binary toxin. Only 31 (31.3%) strains possessed the cdtB gene and 22 (22.2%) contained both genes for the binary toxin subunits (the cdtB and cdtA genes). A relatively large number of the strains tested had genes encoding toxins, whose presence may result in a severe course of disease. Therefore, the accurate diagnosis of patients, including the detection of all known C. difficile toxin genes, is very important. The multiplex PCR method allows for the quick and accurate determination of whether the tested strains of this bacterium contain toxin genes. Agarose gel electrophoresis is a useful tool for visualizing amplification products, allowing one to confirm the presence of specific C. difficile toxin genes as well as investigate their dissemination for epidemiological purposes.

Challenges of infectious diseases in older adults: From immunosenescence and inflammaging through antibiotic resistance to management strategies

Infectious diseases in older adults present a significant challenge to the healthcare system, marked by increased morbidity, mortality, and rising costs of care. Age-related changes (ARCs) in the immune system, including immunosenescence and inflammaging, contribute to heightened susceptibility to severe infections and reduced vaccine responsiveness. Additionally, alterations in the normal microbial flora due to aging and factors such as antibiotic therapy predispose older individuals to infections and age-related diseases. Changes in body composition also affect the pharmacokinetics and pharmacodynamics of drugs, complicating the management of antibiotics and leading to potential overdoses, adverse drug reactions, or underdoses that foster antibiotic resistance. The inappropriate use of antibiotics has exacerbated the emergence of multidrug-resistant pathogens, posing a critical global concern. This narrative review provides an overview of immunosenescence and inflammaging and focuses on three major infectious diseases affecting older adults: bacterial pneumonia, urinary tract infections, and Clostridium difficile infections. Through this exploration, we aim to highlight the need for targeted approaches in managing infectious diseases in the aging population.

In Vitro Activity of Dalbavancin and Fourteen Other Antimicrobial Agents Against Toxigenic Clostridioides Difficile Clinical Isolates in a Greek Tertiary-Care Hospital

OBJECTIVE

Clostridioides difficile is a major cause of healthcare-associated diarrhea worldwide. For years, metronidazole and vancomycin were considered the standard treatment for C. difficile infection (CDI). However, they are increasingly being associated with treatment failure and recurrence. In this study we investigated the in vitro activity of dalbavancin and fourteen other antimicrobials against 155 toxigenic C. difficile isolates originating from patients with C. difficile-associated diarrhea.

MATERIALS AND METHODS

Antimicrobial susceptibility was evaluated by the MIC Test Strip and the results were interpreted using both the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial susceptibility Testing (EUCAST) breakpoints.

RESULTS

C. difficile isolates were fully susceptible to metronidazole, vancomycin, amoxicillin/ clavulanate, piperacillin/tazobactam, and tigecycline. All isolates were dalbavancin susceptible by the CLSI breakpoint (≤ 0.25 μg/ml) compared with 97.4% susceptibility by the EUCAST breakpoint (≤ 0.125 μg/ml). Dalbavancin demonstrated significantly lower MIC50 and MIC90 values compared to vancomycin (0.047 vs. 0.38 and 0.125 vs. 0.5, respectively, p < 0.001). Resistance rates to penicillin, ampicilin, cefoxitin, imipenem, meropenem, clindamycin, moxifloxacin, chloramphenicol, and tetracycline were 20%, 14.2% , 100%, 75.5%, 0.6%, 51%, 36.1%, 3.2%, and 14.8%, respectively. Multidrug-resistant (MDR) phenotypes were detected among 41.3% of the isolates.

CONCLUSION

Dalbavancin exhibited potent activity against the isolates tested. As C. difficile is an important healthcare-associated pathogen, continued surveillance is required to monitor for development of resistance.

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 resistance to antibiotics, including post-COVID-19 data

INTRODUCTION

Updating data on Clostridioides difficile antibiotic resistance is important for treatment improvement of C. difficile infections (CDIs).

AREAS COVERED

Results from 20 countries were included. The mean resistance to 2 mg/l vancomycin, 2 mg/l metronidazole, 4 mg/l moxifloxacin, and 4 mg/l clindamycin was 4.7% (0 to ≥ 26% in two studies), 2.6% (0 to ≥ 40% in 3 studies), 34.9% (6.6->80%), and 61.0% (30->90%), respectively. Resistance to erythromycin (>60-88%), rifampin (>23-55.0%), imipenem (0.6 to > 78% in a clone), tigecycline (0-<5.0%), and fidaxomicin (0-2%) was also found. Resistance to ≥ 5 antibiotics of different classes was reported in some countries. High resistance and multidrug resistance were observed in hypervirulent and epidemic strains. Although only 1% of COVID-19 patients had CDIs, the proportion might be underestimated.

EXPERT OPINION

C. difficile antimicrobial susceptibility varied by country/region, study period, and circulating ribotypes. For CDI treatment, fidaxomicin (preferably) or vancomycin is recommended, while metronidazole is suitable for mild infections. New approaches, including biotherapeutics (Rebyota), strains, antibiotics (ridinilazole and ibezapolstat), and monoclonal antibodies/cocktails merit further evaluation. Because of the resistance rate variations, C. difficile antibiotic susceptibility should be regularly monitored. Post-COVID-19 resistance should be separately presented. Some discrepancies between vancomycin and metronidazole results need to be clarified.

The Hospital Environment as a Potential Source for Clostridioides difficile Transmission Based on Spore Detection Surveys Conducted at Paediatric Oncology and Gastroenterology Units

Clostridioides difficile is an anaerobic, Gram-positive bacterium widely present in the hospital environment due to its ability to generate spores. The transfer of spores to patients through the hands of medical personnel is one of the most frequent paths of C. difficile transmission. In paediatric patients burdened with a serious primary illness requiring long-term hospitalisation and antibiotic therapy, C. difficile may be a significant risk factor for antibiotic-associated diarrhoea. The goal of the study was to assess the state of hospital environments as a potential source of C. difficile spores and to establish the share of hyperepidemic strains at the two paediatric units. The survey for C. difficile was conducted with a C. diff Banana BrothTM medium, used to detect spores and to recover vegetative forms of the bacteria. Environmental samples (n = 86) and swabs from the clothing of medical personnel (n = 14) were collected at two units of a paediatric hospital, where the cases of antibiotic-associated diarrhoea with a C. difficile aetiology constitute a significant clinical problem. In 17 samples, a change in the broth's colour was observed, indicating the presence of spores. Out of seven samples, C. difficile strains were cultured. The pathogenic isolates of C. difficile were obtained from swabs collected from elements of beds, a toilet, a door handle and a doctor's uniform. In our study, we indicated points of increased risk of pathogen transmission, which could constitute a source of infection. The clothing of medical personnel may be a dangerous carrier of pathogenic spores. Periodical surveys of hospital environments with the use of specialist microbiological mediums successfully indicate the direction of corrective actions to be undertaken by the medical facility in order to increase patient safety.