High morbidity and mortality of Clostridium difficile infection and its associations with ribotype 002 in Hong Kong

Genomic study of European Clostridioides difficile ribotype 002/sequence type 8

Clostridioides difficile has significant clinical importance as a leading cause of healthcare-associated infections, with symptoms ranging from mild diarrhoea to severe colitis, and possible life-threatening complications. C. difficile ribotype (RT) 002, mainly associated with MLST sequence type (ST) 8, is one of the most common RTs found in humans. This study aimed at investigating the genetic characteristics of 537 C. difficile genomes of ST8/RT002. To this end, we sequenced 298 C. difficile strains representing a new European genome collection, with strains from Germany, Denmark, France and Portugal. These sequences were analysed against a global dataset consisting of 1,437 ST8 genomes available through Enterobase. Our results showed close genetic relatedness among the studied ST8 genomes, a diverse array of antimicrobial resistance (AMR) genes and the presence of multiple mobile elements. Notably, the pangenome analysis revealed an open genomic structure. ST8 shows relatively low overall variation. Thus, clonal isolates were found across different One Health sectors (humans, animals, environment and food), time periods, and geographical locations, suggesting the lineage's stability and a universal environmental source. Importantly, this stability did not hinder the acquisition of AMR genes, emphasizing the adaptability of this bacterium to different selective pressures. Although only 2.4 % (41/1,735) of the studied genomes originated from non-human sources, such as animals, food, or the environment, we identified 9 cross-sectoral core genome multilocus sequence typing (cgMLST) clusters. Our study highlights the importance of ST8 as a prominent lineage of C. difficile with critical implications in the context of One Health. In addition, these findings strongly support the need for continued surveillance and investigation of non-human samples to gain a more comprehensive understanding of the epidemiology of C. difficile.

Clostridioides difficile infection: history, epidemiology, risk factors, prevention, clinical manifestations, treatment, and future options

SUMMARYClostridioides difficile infection (CDI) is one of the major issues in nosocomial infections. This bacterium is constantly evolving and poses complex challenges for clinicians, often encountered in real-life scenarios. In the face of CDI, we are increasingly equipped with new therapeutic strategies, such as monoclonal antibodies and live biotherapeutic products, which need to be thoroughly understood to fully harness their benefits. Moreover, interesting options are currently under study for the future, including bacteriophages, vaccines, and antibiotic inhibitors. Surveillance and prevention strategies continue to play a pivotal role in limiting the spread of the infection. In this review, we aim to provide the reader with a comprehensive overview of epidemiological aspects, predisposing factors, clinical manifestations, diagnostic tools, and current and future prophylactic and therapeutic options for C. difficile infection.

The burden of Clostridioides difficile infections in South-East Asia and the Western Pacific: A narrative review

BACKGROUND

Clostridioides difficile (formerly Clostridium difficile) is well-documented in Europe and North America to be a common cause of healthcare-associated gastrointestinal tract infections. In contrast, C difficile infection (CDI) is infrequently reported in literature from Asia, which may reflect a lack of clinician awareness. We conducted a narrative review to better understand CDI burden in Asia.

METHODS

We searched the PubMed database for English language articles related to C difficile, Asia, epidemiology, and molecular characteristics (eg, ribotype, antimicrobial resistance).

RESULTS

Fifty-eight articles that met eligibility criteria were included. C difficile prevalence ranged from 7.1% to 45.1 % of hospitalized patients with diarrhea, and toxigenic strains among all C difficile in these patients ranged from 68.2% to 91.9 % in China and from 39.0% to 60.0 % outside of China. Widespread C difficile ribotypes were RT017, RT014/020, RT012, and RT002. Recurrence in patients with CDI ranged from 3.0% to 17.2 %. Patients with CDI typically had prior antimicrobial use recently. High rates of resistance to ciprofloxacin, clindamycin, and erythromycin were frequently reported.

CONCLUSION

The regional CDI burden in Asia is still incompletely documented, seemingly due to low awareness and limited laboratory testing. Despite this apparent under recognition, the current CDI burden highlights the need for broader surveillance and for application of preventative measures against CDI in Asia.

Polymicrobial bacteraemia with Clostridioides difficile and Pseudomonas aeruginosa in an elderly man following antibiotic use

Clostridioides difficile is a micro-organism well known to cause pseudomembranous colitis with rare extraintestinal manifestations. We present the case of an elderly male with multiple comorbidities who presented with acute onset of fever/chills and hypotension, found to have polymicrobial bacteraemia with C. difficile and Pseudomonas aeruginosa He was treated with piperacillin/tazobactam for P. aeruginosa bacteraemia, oral vancomycin for C. difficile colitis and intravenous, followed by oral metronidazole for C. difficile bacteraemia. Pseudomonas cleared after 1 day, and Clostridioides cleared after 4 days. Following an initial septic presentation, he responded appropriately to antimicrobial therapy and did well in follow-up.

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.

Trends in Incidence and Clinical Outcomes of Clostridioides difficile Infection, Hong Kong

Surveillance of C. difficile infections suggests correlation of incidence to antibiotic stewardship programs.

We conducted a territorywide survey to investigate the epidemiology, risk factors, and clinical outcomes of Clostridioides difficile infection (CDI) among hospitalized patients in Hong Kong. A total of 17,105 cases of CDI were identified, of which 15,717 (91.9%) were healthcare-associated and 1,025 (6.0%) were community-associated. Although CDI incidence increased substantially from 2006 to 2017, it plateaued in 2018 and 2019. The 30-day mortality rates decreased from 20.1% in 2015 to 16.8% in 2019, whereas the 60-day recurrence rates remained constant at ≈11% during the study period. Cross-correlation statistic showed significant correlations between incidence trend and overall antimicrobial drug use (r = 0.865, p<0.001), which has decreased as a result of an antibiotic stewardship program initiated in 2017. Our data suggest a turning point in C. difficile epidemiology that could be related to the changing pattern of antimicrobial drug use.

Prevalence of Clostridium difficile and its toxins in hospital patients with diarrhoeal diseases in Lusaka, Zambia

BACKGROUND

Clostridium difficile infection (CDI) has emerged as an important nosocomial and antibiotic-associated diarrhoeal problem leading to increasing morbidity and mortality, especially in resource-privileged regions. CDI varies in incidence, pathogenicity and risk factors across geographical locations, yet little information is available on CDI in sub-Saharan Africa. This study aimed to determine the prevalence of Clostridium difficile and related toxin expression in stool specimens from patients with diarrhoeal disease at the University Teaching Hospital, Lusaka, Zambia.

METHODS

Between June and September 2017, patients presenting with acute or persistent diarrhoea provided stool samples that were cultured anaerobically on cycloserine cefoxitin fructose agar. Isolates were identified by Gram staining, C. difficile latex agglutination and confirmed by PCR targeting of the tpi housekeeping gene. Toxins A or B were detected by ELISA.

RESULTS

Of 135 participants enrolled, 13 (10%) were C. difficile positive, of which four (31%) were toxigenic by ELISA. Among HIV-positive and HIV-negative participants, the frequency of culturable C. difficile (19% vs 12%; p=0.17) and of toxigenic isolates (15% vs 0%, p=0.19) did not differ.

CONCLUSIONS

We can now revise previous research and confirm that CDI contributes to diarrhoea among hospitalised adult patients irrespective of HIV status.

Systematic review on the definition and predictors of severe Clostridiodes difficile infection

Clostridiodes difficile infection (CDI) is one of the most common hospital-acquired infections with high mortality rates. Optimal management of CDI depends on early recognition of severity. However, currently, there is no acceptable standard of prediction. We reviewed severe CDI predictors in published literature and its definition according to clinical guidelines. We systematically reviewed studies describing clinical predictors for severe CDI in medical databases (Cochrane, EMBASE, Global Health Library, and MEDLINE/PubMed). They were independently evaluated by two reviewers. Six hundred thirty-three titles and abstracts were screened, and 31 studies were included. We excluded studies that were restricted to a specific patient population. There were 16 articles that examined mortality in CDI, as compared with 15 articles investigating non-mortality outcomes of CDI. The commonest risk factors identified were comorbidities, white blood cell count, serum albumin level, age, serum creatinine level and intensive care unit admission. Generally, the studies had small patient populations, were retrospective in nature, and mostly from Western centers. The commonest severe CDI criteria in clinical guidelines were raised white blood cell count, followed by low serum albumin and raised serum creatinine levels. There was no commonly agreed upon definition of severe CDI severity in the literature. Current clinical guidelines' definitions for severe CDI are heterogeneous. Hence, there is a need for prospective multi-center studies using standardized protocol for biospecimen investigation collection and shared data on outcomes of patients in order to devise a universally accepted definition for severe CDI.

Benzyl and benzoyl benzoic acid inhibitors of bacterial RNA polymerase-sigma factor interaction

Transcription is an essential biological process in bacteria requiring a core enzyme, RNA polymerase (RNAP). Bacterial RNAP is catalytically active but requires sigma (σ) factors for transcription of natural DNA templates. σ factor binds to RNAP to form a holoenzyme which specifically recognizes a promoter, melts the DNA duplex, and commences RNA synthesis. Inhibiting the binding of σ to RNAP is expected to inhibit bacterial transcription and growth. We previously identified a triaryl hit compound that mimics σ at its major binding site of RNAP, thereby inhibiting the RNAP holoenzyme formation. In this study, we modified this scaffold to provide a series of benzyl and benzoyl benzoic acid derivatives possessing improved antimicrobial activity. A representative compound demonstrated excellent activity against Staphylococcus epidermidis with minimum inhibitory concentrations reduced to 0.5 μg/mL, matching that of vancomycin. The molecular mechanism of inhibition was confirmed using biochemical and cellular assays. Low cytotoxicity and metabolic stability of compounds demonstrated the potential for further studies.

Laboratory-Based Surveillance of Clostridium difficile Infection in Australian Health Care and Community Settings, 2013 to 2018

In the early 2000s, a binary toxin (CDT)-producing strain of Clostridium difficile, ribotype 027 (RT027), caused extensive outbreaks of diarrheal disease in North America and Europe. This strain has not become established in Australia, and there is a markedly different repertoire of circulating strains there compared to other regions of the world. The C. difficile Antimicrobial Resistance Surveillance (CDARS) study is a nationwide longitudinal surveillance study of C. difficile infection (CDI) in Australia. Here, we describe the molecular epidemiology of CDI in Australian health care and community settings over the first 5 years of the study, 2013 to 2018. Between 2013 and 2018, 10 diagnostic microbiology laboratories from five states in Australia participated in the CDARS study. From each of five states, one private (representing community) and one public (representing hospitals) laboratory submitted isolates of C. difficile or PCR-positive stool samples during two collection periods per year, February-March (summer/autumn) and August-September (winter/spring). C. difficile was characterized by toxin gene profiling and ribotyping. A total of 1,523 isolates of C. difficile were studied. PCR ribotyping yielded 203 different RTs, the most prevalent being RT014/020 (n = 449; 29.5%). The epidemic CDT⁺ RT027 (n = 2) and RT078 (n = 6), and the recently described RT251 (n = 10) and RT244 (n = 6) were not common, while RT126 (n = 17) was the most prevalent CDT⁺ type. A heterogeneous C. difficile population was identified. C. difficile RT014/020 was the most prevalent type found in humans with CDI. Continued surveillance of CDI in Australia remains critical for the detection of emerging strain lineages.

Biological characteristics associated with virulence in Clostridioides difficile ribotype 002 in Hong Kong

Clostridioides difficile infection (CDI) is a common cause of nosocomial diarrhea and can sometimes lead to pseudo-membranous colitis and toxic megacolon. We previously reported that the PCR ribotype 002 was a common C. difficile ribotype in Hong Kong that was associated with increased mortality. In this study, we assessed in vitro bacteriological characteristics and in vivo virulence of ribotype 002 compared to other common ribotypes, including ribotypes 012, 014 and 046. We observed significantly higher toxin A (p < 0.05) and toxin B (p < 0.05) production, sporulation (p < 0.001) and germination rates (p < 0.0001) in ribotype 002 than other common ribotypes. In a murine model of C. difficile infection, ribotype 002 caused significantly more weight loss (p < 0.001) and histological damage (p < 0.001) than other common ribotypes. These findings may have contributed to the higher prevalence and mortality observed, and provided mechanistic insights that can help public surveillance and develop novel therapeutics to combat against this infection.

Risk factors and treatment outcomes of severe Clostridioides difficile infection in Singapore

Severe Clostridioides difficile infection (CDI) is associated with poorer outcomes. We aimed to identify risk factors and treatment outcomes of severe CDI. This was a retrospective cohort study. Eligible patients from January to December 2012 were recruited. Severity definitions were in accordance with SHEA/IDSA 2010 guideline. Treatment outcomes were (1) diarrhoea persistence, (2) CDI recurrence, (3) major complications despite treatment and (4) 30-day mortality. Two hundred and seventy-two patients were included and 40% had severe CDI. High APACHE II score (aOR 1.112, 95% CI 1.014–1.219; p < 0.05), high C-reactive protein (aOR 1.011; 95% CI 1.004–1.019; p < 0.01) and carbapenem usage in past 90 days (aOR 3.259; 95% CI 1.105–9.609; p < 0.05) were independent risk factors of severe CDI. Majority received oral metronidazole as sole treatment (92.6% for mild-moderate, 83.9% for severe, 77% for severe-complicated). Diarrhoea persistence was 32% versus 50% (p < 0.01), CDI recurrence 16.6% versus 16.5% (p > 0.05), major complications 1.2% versus 11% (p < 0.001) and 30-day mortality 7.4% versus 20.2% (p < 0.01) in mild-moderate CDI and severe CDI groups respectively. Oral metronidazole for severe CDI was associated with persistent diarrhoea, major complications and mortality. Risk factors for severe CDI can guide doctors in diagnosing severe CDI earlier and instituting oral vancomycin treatment to improve outcomes from severe CDI.

Highly antibiotic-resistant Clostridium difficile isolates from Iranian patients

AIMS

Little is known about the resistance rate and susceptibility profile of Clostridium difficile isolates in Iran. Therefore, the aim of present study is to assess the rate of drug-resistant C. difficile.

METHODS AND RESULTS

During a 6-year period, four hospitals submitted 735 stool specimens from patients suspected for C. difficile infections to the anaerobic bacteriology laboratory. The 46 C. difficile isolates were subjected to disc diffusion and minimum inhibitory concentration (MIC) Test Strips. All isolates were susceptible to vancomycin (VAN) while the highly resistant phenotypes of metronidazole (MTZ) (67·4%), moxifloxacin (78·3%), ciprofloxacin (69·5%) and tetracycline (82·6%) were observed. Of more concern, 67·3% of C. difficile isolates displayed multidrug-resistant phenotypes. More than half of the isolates (n = 27, 58·6%) were coresistant to ciprofloxacin and moxifloxacin. The MIC90 of VAN was ≤2 mg l^-1 , whereas this value for MTZ, ciprofloxacin, moxifloxacin and tetracycline was higher than the resistance breakpoints. According to the comparison of interpretive categories for two tests, the categorical agreement was less than 90% for VAN, ciprofloxacin and tetracycline.

CONCLUSIONS

The disc diffusion method can be used to detect the isolates with reduced susceptibility to MTZ or moxifloxacin. The high rate of resistance to fluoroquinolones highlights the possibility of the emergence of hypervirulent strains in our settings.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides data regarding the high level of resistance against multiple antibiotics except VAN.

Cost-effectiveness analysis of ribotype-guided fecal microbiota transplantation in Chinese patients with severe Clostridium difficile infection

Background

Clostridium difficile infection (CDI) caused by ribotype 002 strain is associated with poor outcomes in Chinese patients. Fecal microbiota transplantation (FMT) is an effective but costly treatment for CDI. We aimed to examine potential cost-effectiveness of ribotype-guided FMT in Chinese patients with severe CDI.

Methods

A decision-analytic model was designed to simulate outcomes of ribotype 002-guided FMT versus vancomycin treatment in Chinese patients with severe CDI in the hospital setting. Outcome measures included mortality rate; direct medical cost; and quality-adjusted life year (QALY) loss for CDI. Sensitivity analysis was performed to examine robustness of base-case results.

Results

Comparing to vancomycin treatment, ribotype-guided FMT group reduced mortality (11.6% versus 17.1%), cost (USD8,807 versus USD9,790), and saved 0.472 QALYs in base-case analysis. One-way sensitivity analysis found the ribotype-guided FMT group to remain cost-effective when patient acceptance rate of FMT was >0.6% and ribotype 002 prevalence was >0.07%. In probabilistic sensitivity analysis, ribotype-guided FMT gained higher QALYs at 100% of simulations with mean QALY gain of 0.405 QALYs (95%CI: 0.400–0.410; p<0.001). The ribotype-guided group was less costly in 97.9% of time, and mean cost-saving was USA679 (95%CI: 670–688; p<0.001).

Conclusions

In the present model, ribotype-guided FMT appears to be a potential option to save QALYs and cost when comparing with vancomycin. The cost-effectiveness of ribotype-guided FMT is subject to the patient acceptance to FMT and prevalence of ribotype 002.

High Prevalence and Frequent Acquisition of Clostridium difficile Ribotype 002 Among Nursing Home Residents in Hong Kong

OBJECTIVETo determine the incidence and risk factors associated with Clostridium difficile colonization among residents of nursing homes and to identify the ribotypes of circulating C. difficile strains.DESIGNA prospective cohort study with a follow-up duration of 22 months.SETTINGNursing homes.PARTICIPANTSOf the 375 residents in 8 nursing homes, 300 residents (80.0%) participated in the study. A further prospective study of 4 nursing homes involving 141 residents with a minimum of 90 days of follow-up was also performed.METHODSBaseline and 90-day stool cultures were obtained; additional stool cultures were obtained for residents who had been discharged from hospitals. Polymerase chain reaction (PCR) ribotyping and slpA typing were performed for all C. difficile strains isolated.RESULTSToxigenic C. difficile was isolated in 30 residents (10%) at baseline, and 9 residents (7.3%) had acquired toxigenic C. difficile in the nursing homes. The presence of nasogastric tube was an independent risk factor (adjusted odds ratio, 8.59; 95% confidence interval, 1.18-62.53; P=.034) for C. difficile colonization. The Kaplan-Meier estimate of median carriage duration was 13 weeks. The C. difficile ribotypes most commonly identified were 002 (40.8%), 014 (16.9%), 029 (9.9%), and 053 (8.5%).CONCLUSIONSThe high incidence of C. difficile colonization and the overrepresentation of C. difficile ribotype 002 confirmed the contribution of nursing home residents to C. difficile transmission across the continuum of care. An infection control program is needed in long-term care.Infect Control Hosp Epidemiol 2018;782-787.

Surveillance of antibiotic resistance among common Clostridium difficile ribotypes in Hong Kong

Incidence of Clostridium difficile infection (CDI) is rapidly increasing and it poses a major health burden globally. However, data regarding the epidemiology of CDI in Asia are limited. We aimed to characterize the antimicrobial susceptibility patterns of common ribotypes of toxigenic C. difficile in Hong Kong. Fifty-three PCR ribotypes were identified among 284 toxigenic C. difficile clinical isolates. The five most prevalent ribotypes were 002 (13%), 017 (12%), 014 (10%), 012 (9.2%), and 020 (9.5%). All tested C. difficile strains remained susceptible to metronidazole, vancomycin, meropenem and piperacillin/tazobactam, but highly resistant to cephalosporins. Of the fluoroquinolones, highest resistance to ciprofloxacin was observed (99%), followed by levofloxacin (43%) and moxifloxacin (23%). The two newly emerged PCR ribotypes, 017 and 002, demonstrated high levels of co-resistance towards clindamycin, tetracycline, erythromycin and moxifloxacin. PCR ribotypes 017 and 002 with multi-drug resistance are rapidly emerging and continuous surveillance is important to monitor the epidemiology of C. difficile to prevent outbreaks of CDI.

Fatal community-acquired ribotype 002 Clostridium difficile bacteremia

Extra-colonic infections, and especially bacteremia, are infrequent manifestations of Clostridium difficile infection. C. difficile bacteremia is generally health-care associated and polymicrobial. We report the case of a patient on hunger strike that presented a C. difficile colitis and mono-microbial bacteremia on its admission to the hospital. Multilocus variable number tandem repeat analysis of stool and blood isolates indicated clonality. The strain was characterized as a ribotype 002, an emerging ribotype previously associated with high fatality rate. The patient received treatment by intra-venous amoxicillin-clavulanate and oral vancomycin but eventually died on the seventh day of admission with concomitant pneumonia and pulmonary embolism.