Antimicrobial susceptibility of Clostridium difficile isolates in Israel

Antimicrobial susceptibilities, resistance mechanisms and molecular characteristics of toxigenic Clostridioides difficile isolates in a large teaching hospital in Chongqing, China

OBJECTIVES

Clostridioides difficile ranks among the primary sources of healthcare-related infections and diarrhoea in numerous nations. We evaluated the drug susceptibility and resistance mechanisms of C. difficile isolates from a hospital in Chongqing, China, and identified resistance rates and resistance mechanisms that differed from previous findings.

METHODS

The toxin genes and drug resistance genes of clinical strains were detected using Polymerase Chain Reaction (PCR), and these strains were subjected to Multilocus Sequence Typing (MLST). The agar dilution technique was employed for assessing susceptibility of antibiotics. Clinical data collection was completed through a review of electronic medical records.

RESULTS

A total of 67 strains of toxin-producing C. difficile were detected. All C. difficile isolates demonstrated susceptibility to both metronidazole and vancomycin. However, resistance was observed in 8.95%, 16.42%, 56.72%, 56.72%, 31.34% and 5.97% of the isolates for tigecycline, tetracycline, clindamycin, erythromycin, moxifloxacin and rifampin, respectively. Among the strains with toxin genotypes A + B + CDT - and belonging to the ST3, six strains exhibited reduced susceptibility to tigecycline (MIC=0.5mg/L) and tetracycline (MIC=8mg/L). The tetA(P) and tetB(P) genes were present in these six strains, but were absent in tetracycline-resistant strains. Resistance genes (ermB, tetM, tetA(P) and tetB(P)) and mutations (in gyrA, gyrB, and rpoB) were identified in resistant strains.

CONCLUSIONS

In contrast to prior studies, we found higher proportions of ST3 isolates with decreased tigecycline sensitivity, sharing similar resistance patterns and resistance genes. In the resistance process of tigecycline and tetracycline, the tetA(P) and tetB(P) genes may play a weak role.

Secondary prophylaxis for Clostridioides difficile infection for patients on non-C. difficile antibiotics: a retrospective cohort study

OBJECTIVES

Recurrent Clostridioides difficile infection (CDI) poses healthcare challenges and morbidity. Preventing recurrence with prophylactic oral CDI antibiotics lack consensus.

METHODS

We used data from the largest healthcare provider in Israel to identify all adults aged 18 years or older diagnosed with a first episode of CDI (Index CDI) between February 2018 and December 2022 and subsequently received a non-CDI antibiotic within 2-8 weeks. Patients who received a concurrent prophylactic CDI antibiotic constituted the CDI prophylaxis group. Multivariable Cox proportional hazard regression models were used to examine the association of secondary CDI prophylaxis with CDI recurrence according to the severity of the index CDI (primary objective) and with 4- and 8-week all-cause mortality (secondary objective).

RESULTS

A total of 434 eligible patients were included. Among them, 327 did not receive CDI antibiotic prophylaxis, while 107 did. CDI antibiotic prophylaxis was associated with a significant risk reduction of CDI recurrence with an adjusted HR of 0.51 (95% CI, 0.27-0.97). The magnitude of the association was modified by the severity of the index CDI episode (P for interaction 0.0182). Specifically, the HR for recurrence was 0.163 (95% CI 0.045-0.593) for non-severe CDI, and 1.242 (95% CI 0.524-2.946) for severe CDI. No significant association was found between CDI antibiotic prophylaxis and 4-8 weeks mortality.

CONCLUSION

Secondary prophylaxis with CDI antibiotics appears to be associated with a reduced risk of recurrence in patients with previous non-severe CDI episode. Further studies are needed to confirm this finding.

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.

Systematic Review and Meta-Analysis on the Frequency of Antibiotic-Resistant Clostridium Species in Saudi Arabia

Clostridium is a genus comprising Gram-positive, rod-shaped, spore-forming, anaerobic bacteria that cause a variety of diseases. However, there is a shortage of information regarding antibiotic resistance in the genus in Saudi Arabia. This comprehensive analysis of research results published up until December 2021 intends to highlight the incidence of antibiotic resistance in Clostridium species in Saudi Arabia. PubMed, Google Scholar, Web of Science, SDL, and ScienceDirect databases were searched using specific keywords, and ten publications on antibiotic resistance in Clostridium species in Saudi Arabia were identified. We found that the rates of resistance of Clostridium difficile to antibiotics were as follows: 42% for ciprofloxacin, 83% for gentamicin, 28% for clindamycin, 25% for penicillin, 100% for levofloxacin, 24% for tetracycline, 77% for nalidixic acid, 50% for erythromycin, 72% for ampicillin, and 28% for moxifloxacin; whereas those of C. perfringens were: 21% for metronidazole, 83% for ceftiofur, 39% for clindamycin, 59% for penicillin, 62% for erythromycin, 47% for oxytetracycline, and 47% for lincomycin. The current findings suggest that ceftiofur, erythromycin, lincomycin, and oxytetracycline should not be used in C. perfringens infection treatments in humans or animals in Saudi Arabia.

Antibacterial and Antibiofilm Activities of Some Plant Essential Oils and Synergistic Effects of Cinnamon Essential Oil with Vancomycin against Clostridioides difficile: in vitro study

The detection of resistant strains of Clostridioides difficile against existing antibiotics and the side effects led to the investigation of alternative agents. Inhibition zones of various essential oils to four strains of C.difficile and other Clostridium species ranged from 8.32-44.18 mm. The highest zone was observed in cinnamon and tea tree essential oils. and The MIC values varied between 0.39-25 (%, v/v). The main components were cinnamaldehyde (85.64%) in cinnamon essential oil, 4-terpineol (83.6%) was determined in tea tree essential oil. Additive effects were found between cinnamon essential oil and vancomycin and between cinnamon and tea tree essential oils, and the FICI values were 0.512 and 0.517, respectively. Both cinnamon and tea tree essential oils showed antibiofilm activities against all tested C. difficile strains at all tested concentrations. Essential oils may be used as a supplement in addition to treatment in the control of C. difficile-related diseases.

Clostridioides difficile epidemiology in the Middle and the Far East

OBJECTIVES

Clostridioides difficile is an important pathogen of healthcare-associated gastrointestinal infections. Recently, an increased number of C. difficile infection (CDI) surveillance data has been reported from Asia. The aim of this review is to summarize the data on the prevalence, distribution and molecular epidemiology of CDI in the Middle and the Far East.

METHODS

Literature was drawn from a search of PubMed up to September 30, 2021.

RESULTS

The meta-analysis of data from 111 studies revealed the pooled CDI prevalence rate in the Middle and the Far East of 12.4% (95% CI 11.4-13.3); 48 studies used PCR for CDI laboratory diagnoses. The predominant types (RT)/sequence type (ST) differ between individual countries (24 studies, 14 countries). Frequently found RTs were 001, 002, 012, 017, 018 and 126; RT017 was predominant in the Far East. The epidemic RT027 was detected in 8 countries (22 studies), but its predominance was reported only in three studies (Israel and Iran). The contamination of vegetable and meat or meat products and/or intestinal carriage of C. difficile in food and companion animals have been reported; the C. difficile RTs/STs identified overlapped with those identified in humans.

CONCLUSIONS

A large number of studies on CDI prevalence in humans from the Middle and the Far East have been published; countries with no available data were identified. The number of studies on C. difficile from non-human sources is limited. Comparative genomic studies of isolates from different sources are needed.

Antibiotic exposure and the risk of hospital-acquired diarrhoea and Clostridioides difficile infection: a cohort study

BACKGROUND

Hospital-acquired diarrhoea (HAD) and Clostridioides difficile infection (CDI) may be triggered by antibiotic use.

OBJECTIVES

To determine the effect of specific antibiotic agents and duration of therapy on the risk of HAD and CDI.

PATIENTS AND METHODS

A single-centre retrospective cohort study was conducted between May 2012 and December 2014 in the internal medicine division. HAD was defined based on documentation of diarrhoea in the medical record or an uncancelled C. difficile test in the laboratory database. CDI was diagnosed using a two-step test (initial glutamate dehydrogenase and toxin A/B EIA, with PCR for discrepant results). Outcomes first occurred on hospital Day 4 or later. Treatment with antibiotics and days of therapy were modelled.

RESULTS

In 29 063 hospitalizations there were 970 HAD events [incidence rate per 10 000 patient days (IR) = 38.5] and 105 CDI events (IR = 3.9). Any antibiotic treatment increased the risk of HAD [adjusted relative risk (aRR) 2.79; 95% CI 2.27-3.43] and CDI (aRR 5.31; 95% CI 2.23-12.69). Each day of β-lactam/β-lactamase inhibitors (βL/βLIs), carbapenems, IV glycopeptides and metronidazole increased the risk of HAD. Each day of βL/βLIs, third- and fourth-generation cephalosporins and carbapenems increased the risk of CDI by over 2%.

CONCLUSIONS

Preventing HAD and CDI should focus on reducing the overall use of antibiotics and shortening antibiotic exposure, rather than focusing on specific agents.

Plasmid Acquisition Alters Vancomycin Susceptibility in Clostridioides difficile

The increasing incidence of primary and recurring Clostridioides difficile infections (CDI), which evade current treatment strategies, reflects the changing biology of C difficile. Here, we describe a putative plasmid-mediated mechanism potentially driving decreased sensitivity of C difficile to vancomycin treatment. We identified a broad host range transferable plasmid in a C difficile strain associated with lack of adequate response to vancomycin treatment. The transfer of this plasmid to a vancomycin-susceptible C difficile isolate decreased its susceptibility to vancomycin in vitro and resulted in more severe disease in a humanized mouse model. Our findings suggest plasmid acquisition in the gastrointestinal tract to be a possible mechanism underlying vancomycin treatment failure in patients with CDI, but further work is needed to characterize the mechanism by which plasmid genes determine vancomycin susceptibility in C difficile.

Antimicrobial resistance in Clostridioides (Clostridium) difficile derived from humans: a systematic review and meta-analysis

Background

Clostridioides (Clostridium) difficile is an important pathogen of healthcare- associated diarrhea, however, an increase in the occurrence of C. difficile infection (CDI) outside hospital settings has been reported. The accumulation of antimicrobial resistance in C. difficile can increase the risk of CDI development and/or its spread. The limited number of antimicrobials for the treatment of CDI is matter of some concern.

Objectives

In order to summarize the data on antimicrobial resistance to C. difficile derived from humans, a systematic review and meta-analysis were performed.

Methods

We searched five bibliographic databases: (MEDLINE [PubMed], Scopus, Embase, Cochrane Library and Web of Science) for studies that focused on antimicrobial susceptibility testing in C. difficile and were published between 1992 and 2019. The weighted pooled resistance (WPR) for each antimicrobial agent was calculated using a random- effects model.

Results

A total of 111 studies were included. The WPR for metronidazole and vancomycin was 1.0% (95% CI 0–3%) and 1% (95% CI 0–2%) for the breakpoint > 2 mg/L and 0% (95% CI 0%) for breakpoint ≥32 μg/ml. Rifampin and tigecycline had a WPRs of 37.0% (95% CI 18–58%) and 1% (95% CI 0–3%), respectively. The WPRs for the other antimicrobials were as follows: ciprofloxacin 95% (95% CI 85–100%), moxifloxacin 32% (95% CI 25–40%), clindamycin 59% (95% CI 53–65%), amoxicillin/clavulanate 0% (0–0%), piperacillin/tazobactam 0% (0–0%) and ceftriaxone 47% (95% CI 29–65%). Tetracycline had a WPR 20% (95% CI 14–27%) and meropenem showed 0% (95% CI 0–1%); resistance to fidaxomicin was reported in one isolate (0.08%).

Conclusion

Resistance to metronidazole, vancomycin, fidaxomicin, meropenem and piperacillin/tazobactam is reported rarely. From the alternative CDI drug treatments, tigecycline had a lower resistance rate than rifampin. The high-risk antimicrobials for CDI development showed a high level of resistance, the highest was seen in the second generation of fluoroquinolones and clindamycin; amoxicillin/clavulanate showed almost no resistance. Tetracycline resistance was present in one fifth of human clinical C. difficile isolates.

Does early corticosteroid therapy affect prognosis in IBD patients hospitalized with Clostridioides difficile infection?

BACKGROUND

Corticosteroids (CS) therapy to Clostridioides difficile infection (CDI) in inflammatory bowel disease (IBD) flares may worsen CDI outcomes.

AIM

Assess the impact of early CS exposure on outcomes of IBD patients diagnosed with CDI.

METHODS

Retrospective study of IBD patients admitted with first-time CDI between 2002 and 2018. Comparisons were made based on CS exposure 48 h from admission. Patients were further subdivided to 5 groups based on CS-antibiotics temporal exposure. The primary outcome was all-cause mortality or colectomy within 3 months. Secondary outcomes were colectomy and mortality rates at 1 year, length of stay, readmissions, bacteremia, and diarrhea improvement by day 7/discharge. Cox proportional hazard model and Kaplan-Meier curves were used to assess the effects on survival. Logistic and ordinal regressions were used to assess primary and secondary outcomes.

RESULTS

One hundred thirteen patients (64 CD, 46 UC, and 3 IBDU) were included, 82 (72.5%) received early CS. At baseline, CRP was significantly lower and albumin was higher in the group not exposed to early CS. At 3 months, 4 (4.8%) patients required colectomy and 6 (5.8%) died (p = NS). Length of stay was significantly reduced among patients not exposed to early CS. All other endpoints were not associated with CS exposure. In subgroup analysis, the primary outcome was not significantly different among the sub-groups. Mortality rate at 1 year was significantly lower in patients who did not receive antibiotics for CDI.

CONCLUSION

Early CS therapy in IBD patients hospitalized with CDI is not associated with worse clinical outcomes. However, additional prospective research is required.

Recommendations and guidelines for the treatment of Clostridioides difficile infection in Taiwan

Clostridioides difficile infection (CDI) is a major enteric disease associated with antibiotic use and a leading cause of hospital-acquired infections worldwide. This is the first guideline for treatment of CDI in Taiwan, aiming to optimize medical care for patients with CDI. The target audience of this document includes all healthcare personnel who are involved in the medical care of patients with CDI. The 2018 Guidelines Recommendations for Evidence-based Antimicrobial agents use in Taiwan (GREAT) working group was formed, comprising of infectious disease specialists from 13 medical centers in Taiwan, to review the evidence and draft recommendations using the grading of recommendations assessment, development, and evaluation (GRADE) methodology. A nationwide expert panel reviewed the recommendations during a consensus meeting in March 2019. The recommendation is endorsed by the Infectious Diseases Society of Taiwan (IDST). This guideline describes the epidemiology and risk factors of CDI, and provides recommendations for treatment of CDI in both adults and children. Recommendations for treatment of the first episode of CDI, first recurrence, second and subsequent recurrences of CDI, severe CDI, fulminant CDI, and pediatric CDI are provided.

Molecular Characterization and Moxifloxacin Susceptibility of Clostridium difficile

In recent years, the incidence and severity of Clostridium difficile infections has increased. Additionally, resistance of C. difficile to frequently used antibiotics is rising. To improve our understanding of C. difficile, there is a need for molecular characterization of different strains and antibiotic resistance testing. We investigated the efficacy of GenoType CDiff kit (Hain Lifesciences) in identification of C. difficile and its various strains in northern Israel. The kit involves a molecular assay that detects C. difficile from stool samples or colonies and identifies the different strains and mutations in the gyrA gene that cause moxifloxacin resistance. Forty-nine C. difficile positive samples were examined by the kit following DNA extraction from both colonies and stool. The identification rate (95.9%) of C. difficile was much higher when DNA was extracted from colonies, compared to extraction from stool (46.9%). Low frequencies of ribotype027 strain (2%) and of ribotype078 strain (4%) were found. There was a high concordance between genotype (mutation in gyrA) and phenotype (Etest) for moxifloxacin resistance (Kappa = 0.72). A high percentage of moxifloxacin-resistant strains was found. Our findings indicate that the GenoType CDiff kit is very effective in characterization of C.difficile strains and less effective for identification of C. difficile directly from stool samples.

In Vitro Activity of Tedizolid, Dalbavancin, and Ceftobiprole Against Clostridium difficile

Background:Clostridium difficile (C. difficile) is a major nosocomial pathogen that colonizes in the human gut. Recently, the U.S. FDA approved three new antimicrobial agents against gram-positive bacteria: Tedizolid, Dalbavancin, and Ceftobiprole. The efficacy of these antibiotics for treatment of C. difficile infection has not been thoroughly examined. The current study aimed to examine the in vitro activity of these antibiotics against C. difficile. In addition, to compare between Dalbavancin and Ceftobiprole to antibiotics from the same class: Vancomycin and Ceftriaxone, respectively. Methods: Eighty-four C. difficile isolates were tested for susceptibility to Tedizolid, Dalbavancin, Ceftobiprole, Vancomycin, and Ceftriaxone by Etest technique in order to determine the minimum inhibitory concentration (MIC). Results: Upon comparison of the novel antibiotic agents, Dalbavancin demonstrated the lowest MIC values and ceftobiprole the highest at MIC₅₀ (0.016, 0.38, and 1.5 μg/mL, for Dalbavancin, Tedizolid, and Ceftobiprole, respectively) and MIC₉₀ (0.03, 0.78, and 3.17 μg/mL, respectively). Dalbavancin demonstrated significantly lower MIC₅₀ and MIC₉₀ values compared to Vancomycin (0.016 vs. 0.38 and 0.03 vs. 3.5, respectively) (p < 0.001) and ceftobiprole had significantly lower MIC values compare to ceftriaxone (1.5 vs. 32 and 3.17 vs. 28.8, respectively) (p < 0.001). Conclusion: Dalbavancin and Tedizolid may play a role as potential therapeutic agents for treatment of C. difficile infection. Examination of antibiotic effect on the intestinal microbiome and clinical trials are needed for more accurate results.

Clostridium difficile Infections: A Global Overview of Drug Sensitivity and Resistance Mechanisms

Clostridium difficile (C. difficile) is the most prevalent causative pathogen of healthcare-associated diarrhea. Notably, over the past 10 years, the number of Clostridium difficile outbreaks has increased with the rate of morbidity and mortality. The occurrence and spread of C. difficile strains that are resistant to multiple antimicrobial drugs complicate prevention as well as potential treatment options. Most C. difficile isolates are still susceptible to metronidazole and vancomycin. Incidences of C. difficile resistance to other antimicrobial drugs have also been reported. Most of the antibiotics correlated with C. difficile infection (CDI), such as ampicillin, amoxicillin, cephalosporins, clindamycin, and fluoroquinolones, continue to be associated with the highest risk for CDI. Still, the detailed mechanism of resistance to metronidazole or vancomycin is not clear. Alternation in the target sites of the antibiotics is the main mechanism of erythromycin, fluoroquinolone, and rifamycin resistance in C. difficile. In this review, different antimicrobial agents are discussed and C. difficile resistance patterns and their mechanism of survival are summarized.