A retrospective study of community-acquired Clostridium difficile infection in southwest China

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.

Pathogenicity and virulence of Clostridioides difficile

Clostridioides difficile is the most common cause of nosocomial antibiotic-associated diarrhea, and is responsible for a spectrum of diseases characterized by high levels of recurrence, morbidity, and mortality. Treatment is complex, since antibiotics constitute both the main treatment and the major risk factor for infection. Worryingly, resistance to multiple antibiotics is becoming increasingly widespread, leading to the classification of this pathogen as an urgent threat to global health. As a consummate opportunist, C. difficile is well equipped for promoting disease, owing to its arsenal of virulence factors: transmission of this anaerobe is highly efficient due to the formation of robust endospores, and an array of adhesins promote gut colonization. C. difficile produces multiple toxins acting upon gut epithelia, resulting in manifestations typical of diarrheal disease, and severe inflammation in a subset of patients. This review focuses on such virulence factors, as well as the importance of antimicrobial resistance and genome plasticity in enabling pathogenesis and persistence of this important pathogen.

Analysis of risk factors for community-acquired Clostridioides difficile diarrhea in children: a case-control study in Chenzhou, China

Background

Most previous studies on Clostridium difficile infection (CDI) mainly focused on adults with underlying diseases or critical illnesses. However, the number of CDI cases in children has also significantly increased, especially the growth of community-acquired CDI, which has attracted attention. This study was conducted to examine the toxin gene characteristics and the risk factors associated with community-acquired CDI (CA-CDI) in children with diarrhea.

Methods

Children with diarrhea before admission or within 48 hours of hospitalization were included in the study. Stool samples were collected from children with community-acquired diarrhea who were treated at the Children's Hospital of the First People's Hospital of Chenzhou, China from June of 2021 to June of 2022. Fluorescence real-time polymerase chain reaction was utilized to detect Clostridioides difficile (CD) toxins A (tcdA) and B (tcdB) genes as well as binary toxin gene A (cdtA) and B (cdtB) in the specimens cultured for CD. Each child with CA-CDI was matched with four control children of the same sex, age, and place of residence. Necessary clinical data were extracted from the hospital's electronic medical record system. Then, a multivariate conditional logistic regression analysis was applied to identify potential risk factors for CA-CDI.

Results

Sixteen (8.3%) of the 193 stool specimens who tested positive for CD were selected for the case group, and their matching 64 control patients were in the study cohort. The breakdown of the CD genotypes of the 16 positive cases were follows: 14 (tcdA+ and tcdB+) (7.25%) and 2 (tcdA+ and tcdB-) (1.04%). The cdtA and cdtB binary toxin genes were negative in all. The results of multivariate conditional logistic regression analysis identified antibiotic use within the previous month [odds ratio (OR) =5.13; 95% confidence interval (CI): 1.65-15.91] and non-breastfeeding (OR =4.89; 95% CI: 1.11-21.53) as independent risk factors for CDI in pediatric patients experiencing community-acquired diarrhea.

Conclusions

Children who had been treated with antibiotics and not breastfed were more susceptible to CDI. Therefore, in order to prevent and to control the spread of CD infection, being prudent to the aforementioned high-risk factors is strongly advocated in clinical practice.

An epidemiological surveillance study (2021-2022): detection of a high diversity of Clostridioides difficile isolates in one tertiary hospital in Chongqing, Southwest China

BACKGROUND

Clostridioides difficile is a bacterium that causes antibiotic-associated infectious diarrhea and pseudomembranous enterocolitis. The impact of C. difficile infection (CDI) in China has gained significant attention in recent years. However, little epidemiological data are available from Chongqing, a city located in Southwest China. This study aimed to investigate the epidemiological pattern of CDI and explore the drug resistance of C. difficile isolates in Chongqing.

METHODS

A case-control study was conducted to investigate the clinical infection characteristics and susceptibility factors of C. difficile. The features of the C. difficile isolates were evaluated by testing for toxin genes and using multi-locus sequence typing (MLST). The susceptibility of strains to nine antibiotics was determined using agar dilution technique.

RESULTS

Out of 2084 diarrhea patients, 90 were tested positive for the isolation of toxigenic C. difficile strains, resulting in a CDI prevalence rate of 4.32%. Tetracycline, cephalosporins, hepatobiliary disease, and gastrointestinal disorders were identified as independent risk factors for CDI incidence. The 90 strains were classified into 21 sequence types (ST), with ST3 being the most frequent (n = 25, 27.78%), followed by ST2 (n = 10, 11.11%) and ST37 (n = 9, 10%). Three different toxin types were identified: 69 (76.67%) were A+B+CDT-, 12 (13.33%) were A-B+CDT-, and 9 (10%) were A+B+CDT+. Although substantial resistance to erythromycin (73.33%), moxifloxacin (62.22%), and clindamycin (82.22%), none of the isolates exhibited resistance to vancomycin, tigecycline, or metronidazole. Furthermore, different toxin types displayed varying anti-microbial characteristics.

CONCLUSIONS

The strains identified in Chongqing, Southwest China, exhibited high genetic diversity. Enhance full awareness of high-risk patients with HA-CDI infection, particularly those with gastrointestinal and hepatocellular diseases, and emphasize caution in the use of tetracycline and capecitabine. These findings suggest that a potential epidemic of CDI may occur in the future, emphasizing the need for timely monitoring.

Clostridioides (Clostridium) difficile in adults with diarrhoea in Vietnam

BACKGROUND

Clostridioides (Clostridium) difficile causes antimicrobial-associated diarrhoea, however, presentations may range from asymptomatic carriage to severe diarrhoea, life-threatening toxic megacolon and even death. Reports on C. difficile infection (CDI) in Vietnam remain limited. The objectives of this study were to evaluate the epidemiology, molecular characteristics, and antimicrobial susceptibility of C. difficile isolated from adults with diarrhoea in Vietnam.

METHODS

Diarrhoeal stool samples from adult patients aged ≥17 years old were collected at Thai Binh General Hospital in northern Vietnam between 1^st March 2021 and 28th February2022. All samples were transported to The University of Western Australia, Perth, Western Australia for C. difficile culture, toxin gene profiling, PCR ribotyping and antimicrobial susceptibility testing.

RESULTS

A total of 205 stool samples were collected from patients aged from 17 to 101 years old. The overall prevalence of C. difficile was 15.1% (31/205) with the recovery of toxigenic and non-toxigenic isolates 9.8% (20/205) and 6.3% (13/205), respectively. Thus 33 isolates were recovered comprising 18 known ribotypes (RTs) and one novel RT (two samples contained two different RTs in each sample). The most prevalent strains were RT 012 (five strains) and RTs 014/020, 017 and QX 070 three strains each. All C. difficile were susceptible to amoxicillin/clavulanate, fidaxomicin, metronidazole, moxifloxacin and vancomycin, while resistance to varying degrees was seen to clindamycin, erythromycin, tetracycline and rifaximin, 78.8% (26/33), 51.5% (17/33), 27.3% (9/33) and 6.1% (2/33), respectively. The prevalence of multidrug resistance was 27.3% (9/33) and multidrug resistance was most common in toxigenic RT 012 and non-toxigenic RT 038 strains.

CONCLUSION

The prevalence of C. difficile in adults with diarrhoea and multidrug resistance in C. difficile isolates was relatively high. A clinical assessment to differentiate between CDI/disease and colonisation is required.

Prevalence and molecular characterization of Clostridioides difficile infection in China over the past 5 years: a systematic review and meta-analysis

OBJECTIVES

The aim of this study was to provide an overview of the prevalence and molecular characteristics of Clostridioides difficile infection (CDI) in China in the past 5 years.

METHODS

A systematic literature review was conducted according to the preferred reporting items for systematic reviews and meta-analyses guidelines. Nine databases were searched for relevant studies published between January 2017 and February 2022. The Joanna Briggs Institute critical appraisal tool was used to assess the quality of included studies, and R software version 4.1.3 was used for data analysis. Funnel plots and Egger regression tests were also performed to assess publication bias.

RESULTS

A total of 50 studies were included in the analysis. The pooled prevalence of CDI in China was 11.4% (2696/26,852). The main circulating C. difficile strains in southern China were ST54, ST3, and ST37, consistent with the overall situation in China. However, the most prevalent genotype in northern China was ST2, which was previously underappreciated.

CONCLUSION

Based on our findings, increased awareness and management of CDI is necessary to reduce the prevalence of CDI in China.

Community-onset Clostridioides difficile infection in south Serbia

BACKGROUND

Data from the past decade indicates that Clostridioides difficile infection (CDI) is not only a nosocomial infection but is also increasingly recognized as a disease in the community.

OBJECTIVE

We aimed to study community-onset (CO) CDI in the various age groups in south Serbia with its clinical characteristics, risk factors and microbiological characterization.

METHODS

The study group included 93 patients with CO-CDI (median age 62). The control group consisted of 186 patients with community-onset diarrhea and stool samples negative tested for CDI.

RESULTS

Of all CDI cases diagnosed with a community onset, 74.19% had a previous contact with a healthcare facility in the previous 12 weeks, but 34.40% have no record on hospitalization in the previous 12 months. Using a multivariate statistical regression model, the following risk factors for CO-CDI development were found; antacid usage (OR = 0.267, 95%C.I.:0.10-0.291, p < 0.01), chronic kidney disease (OR = 0.234, 95%C.I.:0.10-0.51, p < 0.01) and antibiotic use during the prior 2 months (OR = 0.061, 95%C.I.:0.02-0.17, p < 0.01), especially tetracycline's (OR = 0.146, 95% C.I.:0.07-0.22, p < 0.01) and cephalosporin's (OR = 0.110, 95%C.I.:0.14-0.42, p < 0.01). The most common ribotypes (RTs) detected in patients with CO-CDI were RT001 (32.3%) and RT027 (24.7%). All tested toxin producing C. difficile isolates were sensitive to metronidazole, vancomycin and tigecycline. A high rate of resistance to moxifloxacin (73.11%) and rifampicin (23.65%) was found.

CONCLUSION

Patients with CO-CDI had frequently contact with healthcare facility in the previous 12 weeks. Restriction of antacid usage and of high-risk antibiotics in the community may help reduce the incidence of CO-CDI.

Antibiotic resistance and genomic features of Clostridioides difficile in southwest China

Background

Clostridioides difficile infection (CDI) caused by toxigenic strains leads to antibiotic-related diarrhea, colitis, or even fatal pseudomembranous enteritis. Previously, we conducted a cross-sectional study on prevalence of CDI in southwest China. However, the antibiotics resistance and characteristics of genomes of these isolates are still unknown.

Methods

Antibiotic susceptibility testing with E-test strips and whole genome sequence analysis were used to characterize the features of these C. difficile isolates.

Results

Forty-nine strains of C. difficile were used in this study. Five isolates were non-toxigenic and the rest carried toxigenic genes. We have previously reported that ST35/RT046, ST3/RT001 and ST3/RT009 were the mostly distributed genotypes of strains in the children group. In this study, all the C. difficile isolates were sensitive to metronidazole, meropenem, amoxicillin/clavulanic acid and vancomycin. Most of the strains were resistant to erythromycin, gentamicin and clindamycin. The annotated resistant genes, such as macB, vanRA, vanRG, vanRM, arlR, and efrB were mostly identified related to macrolide, glycopeptide, and fluoroquinolone resistance. Interestingly, 77.55% of the strains were considered as multi-drug resistant (MDR). Phylogenetic analysis based on core genome of bacteria revealed all the strains were divided into clade 1 and clade 4. The characteristics of genome diversity for clade 1 could be found. None of the isolates showed 18-bp deletion of tcdC as RT027 strain as described before, and polymorphism of tcdB showed a high degree of conservation than tcdA gene.

Conclusions

Most of the C. difficile isolates in this study were resistant to macrolide and aminoglycoside antibiotics. Moreover, the MDR strains were commonly found. All the isolates belonged to clade 1 and clade 4 according to phylogenetic analysis of bacterial genome, and highly genomic diversity of clade 1 was identified for these strains.

Epidemiology of Clostridium (Clostridioides) difficile Infection in Southeast Asia

This review describes the current understanding of Clostridium (Clostridioides) difficile infection (CDI) in southeast Asia regarding the prevalence of CDI, C. difficile detection methods, antimicrobial susceptibility profiles, and the potential significance of a One Health approach to prevention and control. Our initial focus had been the Indochina region, however, due to limited studies/surveillance of CDI in Indochina, other studies in southeast Asian countries and neighboring Chinese provinces are presented here for comparison. Clostridium (Clostridioides) difficile infection is one of the most common causes of hospital-acquired gastroenteritis worldwide. Since its discovery as a cause of pseudomembranous colitis in 1978, C. difficile-related disease has been more prevalent in high-income rather than low-income countries. This may be because of a lack of knowledge and awareness about the significance of C. difficile and CDI, resulting in underreporting of true rates. Moreover, the abuse of antimicrobials and paucity of education regarding appropriate usage remain important driving factors in the evolution of CDI worldwide. The combination of underreporting of true CDI rates, along with continued misuse of antimicrobial agents, poses an alarming threat for regions like Indochina. C. difficile ribotype (RT) 027 has caused outbreaks in North America and European countries, however, C. difficile RT 017 commonly occurs in Asia. Toxin A-negative/toxin B-positive (A-B+) strains of RT 017 have circulated widely and caused outbreaks throughout the world and, in southeast Asia, this strain is endemic.

Molecular characterization and antibiotic resistance of Clostridioides difficile in patients with inflammatory bowel disease from two hospitals in China

OBJECTIVE

Patients with inflammatory bowel disease (IBD) are susceptible to Clostridioides difficile infection (CDI), resulting in poor outcomes and recurrence; therefore, the molecular characterization of C. difficle in IBD patients in China needs further investigation.

METHODS

C. difficile strains were isolated and identified from fecal samples of adult and pediatric IBD patients. Toxigenic strains were typed using multilocus sequence typing (MLST) and whole genomic sequencing (WGS) to construct the phylogenetic tree. Susceptibility to 10 antimicrobials was evaluated using the E-test.

RESULTS

Among the 838 IBD patients, 82 toxigenic C. difficile were identified, which comprised 46 from adults and 36 children. 90.2% (74/82) of the isolates were positive for both toxin A and toxin B genes (A+B+), while the remaining 9.8% were negative for toxin A gene, but positive for toxin B gene (A-B+). These toxigenic strains were susceptible to metronidazole and vancomycin, but highly resistant to clindamycin, erythromycin, and fluoroquinolones. All moxifloxacin-resistant isolates had mutations resulting in an amino acid substitution in gryA (T82I). The dominant types were ST-35 (20.7%), ST-2 (17.1%), ST-54 (13.4%), and ST-3 (13.4%) in all patients.

CONCLUSION

The incidence and molecular epidemiology of C. difficile infection in adult IBD patients resembled CDI in the general inpatient population. A higher antibiotic resistance rate was identified among the C. difficile isolates obtained from pediatric IBD patients than adult patients, and few STs accounted for most multidrug-resistant strains. However, the molecular genetic features of the same ST-type between these two groups remains highly correlated.

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.

An Atypical Case of Monomicrobial Clostridioides difficile Septicemia With No Gastrointestinal Manifestations

An uncommon case of monomicrobial Clostridioides difficile septicemia in a 63-year-old man was reported in Zhejiang, China. Once diagnosed, vancomycin treatment cleared the infections. The patient had no remarkable medical history, and the inspection showed no overt gastrointestinal symptoms, though C. difficile was detected in his stool samples. However, we later defined that the C. difficile strain isolated from the blood sample was different from the one isolated from his stool using the whole genome sequencing analysis. By retrospective analysis of his medical record, we noticed that the man had a recent tooth extraction thus the bacterium may have invaded through the root canal. Therefore, we suggest that oral C. difficile colonization may be a potential risk factor for severe C. difficile septicemia, which could be clinically alarming.

Clostridioides (Clostridium) difficile in children with diarrhoea in Vietnam

BACKGROUND

Clostridioides (Clostridium) difficile commonly causes hospital-acquired infection which can range from mild diarrhoea to life-threatening toxic megacolon and even death. Reports on C. difficile infection (CDI) in Vietnam are limited, so this study was designed to evaluate the prevalence, molecular epidemiology and antimicrobial susceptibility of C. difficile isolated from children with diarrhoea in Vietnam. Infants are often colonised with C. difficile and it was hypothesised that those colonising strains would represent strains of C. difficile circulating in the hospital/region at the time, however, this was not an attempt to determine if C. difficile was the cause of the diarrhoea.

METHODS

Diarrhoeal stool samples collected at two children's hospitals in northern Vietnam from 1^st October 2020 to 28^th February 2021 were transported to Perth, Western Australia, for culture of C. difficile and further investigations on isolates; PCR ribotyping, toxin gene profiling and antimicrobial susceptibility testing.

RESULTS

From these hospitals, 370 diarrhoeal stool samples were collected, most from children aged 1-15 months (71.9%; 266/370). The overall prevalence of C. difficile in stool samples from children aged ≤16 years was 37.8% (140/370) and the highest prevalence was in the 2-12 months age group (52.9%; 74/140). In total, 151 isolates of C. difficile were recovered; the proportion of toxigenic isolates was 16.6% (25/151). Of the 25 toxigenic C. difficile isolates, the toxin gene profiles A⁺B⁺CDT^- and A^-B⁺CDT^- comprised 72% and 28%, respectively. The four most prevalent C. difficile ribotypes (RTs) were QX 011 (25/151), RT 010 (25/151), QX 107 (12/151) and RT 012 (11/151). All isolates were susceptible to vancomycin, metronidazole and fidaxomicin, while there was significant resistance to clindamycin (90.1%), and some to moxifloxacin (6.6%) and rifaximin (3.3%).

CONCLUSION

The prevalence of C. difficile in children with diarrhoea was high (37.8%) although the proportion of toxigenic strains was comparatively low. The clinical significance of any isolate needs to be determined.

Genomic Analysis of Clostridioides difficile in 2 Regions of the United States Reveals a Diversity of Strains and Limited Transmission

BACKGROUND

The distribution of Clostridioides difficile strains and transmission dynamics in the United States are not well defined. Whole-genome sequencing across 2 Centers for Disease Control and Prevention Emerging Infections Program C. difficile infection (CDI) surveillance regions (Minnesota and New York) was performed to identify predominant multilocus sequence types (MLSTs) in community-associated (CA) and healthcare-associated (HCA) disease and assess transmission.

METHODS

Whole-genome sequencing was performed on C. difficile isolates from patients with CDI over 3 months between 2016 and 2017. Patients were residents of the catchment area without a positive C. difficile test in the preceding 8 weeks. CDI cases were epidemiologically classified as HCA or CA.

RESULTS

Of 422 isolates, 212 (50.2%) were HCA and 203 (48.1%) were CA. Predominant MLSTs were sequence type (ST) 42 (9.3%), ST8 (7.8%), and ST2 (8.1%). MLSTs associated with HCA-CDI included ST1 (76%), ST53 (83.3%), and ST43 (80.0%), while those associated with CA-CDI included ST3 (76.9%) and ST41 (77.8%). ST1 was more frequent in New York than in Minnesota (10.8% vs 3.1%). Thirty-three pairs were closely related genomically, 14 of which had potential patient-to-patient transmission supported by record review.

CONCLUSIONS

The genomic epidemiology of C. difficile across 2 regions of the United States indicates the presence of a diverse strain profile and limited direct transmission.

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.

Response of the gut microbiota during the Clostridioides difficile infection in tree shrews mimics those in humans

BACKGROUND

Clostridioides difficile is a major cause of antibiotic associated diarrhea. Several animal models are used to study C. difficile infection (CDI). The tree shrew has recently been developed as a model of primate processes. C. difficile infection has not been examined in tree shrews. We infected tree shrews with hyper-virulent C. difficile strains and examined the alterations in gut microbiota using 16S rRNA gene sequencing.

RESULTS

C. difficile colonized the gastrointestinal tract of tree shrew and caused diarrhea and weight loss. Histopathologic examination indicated structures and mucosal cell destruction in ileal and colonic tissues. The gut microbial community was highly diversity before infection and was dominated by Firmicutes, Fusobacteria, Bacteroidetes, and Proteobacteria. Antibiotic administration decreased the diversity of the gut microbiota and led to an outgrowth of Lactobacillus. The relative abundance of Proteobacteria, Gammaproteobacteria, Enterobacteriales, Lachnospiraceae, Enterobacteriaceae, Escherichia, Blautia, and Tyzzerella increased following C. difficile infection. These taxa could be biomarkers for C. difficile colonization.

CONCLUSIONS

In general, the disease symptoms, histopathology, and gut microbiota changes following C. difficile infection in tree shrews were similar to those observed in humans.

Molecular characteristics of Clostridium difficile in children with acute gastroenteritis from Zhejiang

Background

Clostridium difficile infection (CDI) has an increasing pediatric prevalence worldwide. However, molecular characteristics of C. difficile in Chinese children with acute gastroenteritis have not been reported.

Methods

A five-year cross-sectional study was conducted in a tertiary children’s hospital in Zhejiang. Consecutive stool specimens from outpatient children with acute gastroenteritis were cultured for C. difficile, and isolates then were analyzed for toxin genes, multi-locus sequence type and antimicrobial resistance. Diarrhea-related viruses were detected, and demographic data were collected.

Results

A total of 115 CDI cases (14.3%), and 69 co-infected cases with both viruses and toxigenic C. difficile, were found in the 804 stool samples. The 186 C. difficile isolates included 6 of toxin A-positive/toxin B-positive/binary toxin-positive (A⁺B⁺CDT⁺), 139 of A⁺B⁺CDT⁻, 3 of A⁻B⁺CDT⁺, 36 of A⁻B⁺CDT⁻ and 2 of A⁻B⁻CDT⁻. Sequence types 26 (17.7%), 35 (11.3%), 39 (12.4%), 54 (16.7%), and 152 (11.3%) were major genotypes with significant differences among different antimicrobial resistances (Fisher's exact test, P < 0.001). The A⁻B⁺ isolates had significantly higher resistance, compared to erythromycin, rifampin, moxifloxacin, and gatifloxacin, than that of the A⁺B⁺ (χ² = 7.78 to 29.26, P < 0.01). The positive CDI rate in infants (16.2%) was significantly higher than that of children over 1 year old (10.8%) (χ² = 4.39, P = 0.036).

Conclusions

CDI has been revealed as a major cause of acute gastroenteritis in children with various genotypes. The role of toxigenic C. difficile and risk factors of CDI should be emphatically considered in subsequent diarrhea surveillance in children from China.

Characteristics of Clostridium difficile isolates and the burden of hospital-acquired Clostridium difficile infection in a tertiary teaching hospital in Chongqing, Southwest China

BACKGROUND

Clostridium difficile infection (CDI), especially hospital-acquired Clostridium difficile infection (HA-CDI), continues to be a public health problem and has aroused great concern worldwide for years. This study aimed to elucidate the clinical and epidemiological features of HA-CDI and the characteristics of C.difficile isolates in Chongqing, Southwest China.

METHODS

A case-control study was performed to identify the clinical incidence and risk factors of HA-CDI. C. difficile isolates were characterised by polymerase chain reaction (PCR) ribotyping, multilocus sequence typing (MLST), toxin gene detection and antimicrobial susceptibility testing.

RESULTS

Of the 175 suspicious patients, a total of 122 patients with antibiotic-associated diarrhea (AAD) were included in the study; among them, 38 had HA-CDI. The incidence of AAD and HA-CDI was 0.58 and 0.18 per 1000 patient admissions, respectively. Chronic renal disease and cephalosporin use were independent risk factors for HA-CDI. Fifty-five strains were assigned into 16 sequence types (STs) and 15 ribotypes (RTs). ST2/RT449 (8, 14.5%) was the predominant genotype. Of the 38 toxigenic isolates, A + B + CDT- isolates accounted for most (34, 89.5%) and 1 A + B + CDT+ isolate emerged. No isolate was resistant to vancomycin, metronidazole or tigecycline, with A-B-CDT- being more resistant than A + B + CDT-.

CONCLUSIONS

Different genotypes of C. difficile strains were witnessed in Chongqing, which hinted at the necessary surveillance of HA-CDI. Adequate awareness of patients at high risk of HA-CDI acquisition is advocated and cautious adoption of cephalosporins should be highlighted.

The molecular characters and antibiotic resistance of Clostridioides difficile from economic animals in China

BACKGROUND

It has been performed worldwidely to explore the potential of animals that might be a reservoir for community associated human infections of Clostridioides difficile. Several genetically undistinguished PCR ribotypes of C. difficile from animals and human have been reported, illustrating potential transmission of C. difficile between them. Pig and calf were considered as the main origins of C. difficile with predominant RT078 and RT033, respectively. As more investigations involved, great diversity of molecular types from pig and calf were reported in Europe, North American and Australia. However, there were quite limited research on C. difficile isolates from meat animals in China, leading to non-comprehensive understanding of molecular epidemiology of C. difficile in China.

RESULTS

A total of 55 C. difficile were isolated from 953 animal stool samples, within which 51 strains were from newborn dairy calf less than 7 days in Shandong Province. These isolates were divided into 3 STs and 6 RTs, of which ST11/RT126 was predominant type, and responsible for majority antibiotic resistance isolates. All the isolates were resistant to at least one tested antibiotics, however, only two multidrug resistant (MDR) isolates were identified. Furthermore, erythromycin (ERY) and clindamycin (CLI) were the two main resistant antibiotics. None of the isolates were resistant to vancomycin (VAN), metronidazole (MTZ), tetracycline (TET), and rifampin (RIF).

CONCLUSIONS

In this study, we analyzed the prevalence, molecular characters and antibiotic resistance of C. difficile from calf, sheep, chicken, and pig in China. Some unique features were found here: first, RT126 not RT078 were the dominant type from baby calf, and none isolates were got from pig; second, on the whole, isolates from animals display relative lower resistant rate to these 11 tested antibiotics, compared with isolates from human in China in our previous report. Our study helps to deep understanding the situation of C. difficile from economic animals in China, and to further study the potential transmission of C. difficile between meat animals and human.

Significance of Clostridium difficile in community-acquired diarrhea in a tertiary care center in Lebanon

Clostridium difficile infection (CDI) is becoming a cause of community-acquired diarrhea. The aim is to describe (CDI) as a cause of acute diarrhea in patients presenting from the community to the Emergency Department (ED) of a tertiary care center in Lebanon. A retrospective study conducted in the ED at the American University of Beirut Medical Center (AUBMC). Adult patients presenting with the chief complaint of diarrhea and having positive CDI by stool laboratory testing (toxins A and B), during a three-year period were included. 125 patients with CDI were included. Average age was 61.43 (±20.42) with roughly equal sex prevalence. 30% (n = 36) of patients had neither antibiotic exposure nor recent hospitalization prior to current CDI. Mortality was 9.6% (n = 12), CDI was attributed as the cause in 16.7% (n = 2) and a contributing factor in 41.6% (n = 5). Recurrence within 3 months occurred in 9.6% (n = 11) in mainly those taking Proton Pump Inhibitors (PPIs) and having multiple co-morbidities. There is a high rate of community acquired CDI in Lebanon. Review of patients’ medications (PPIs and antibiotics) is crucial. More studies are needed to assess mortality associated with CDI and the outcome of coinfection with other enteric pathogens.

Microevolution within ST11 group Clostridioides difficile isolates through mobile genetic elements based on complete genome sequencing

BACKGROUND

Clade 5 Clostridioides difficile diverges significantly from the other clades and is therefore, attracting increasing attention due its great heterogeneity. In this study, we used third-generation sequencing techniques to sequence the complete whole genomes of three ST11 C. difficile isolates, RT078 and another two new ribotypes (RTs), obtained from three independent hospitalized elderly patients undergoing antibiotics treatment. Mobile genetic elements (MGEs), antibiotic-resistance, drug resistance genes, and virulent-related genes were analyzed and compared within these three isolates.

RESULTS

Isolates 10,010 and 12,038 carried a distinct deletion in tcdA compared with isolate 21,062. Furthermore, all three isolates had identical deletions and point-mutations in tcdC, which was once thought to be a unique characteristic of RT078. Isolate 21,062 (RT078) had a unique plasmid, different numbers of transposons and genetic organization, and harboring special CRISPR spacers. All three isolates retained high-level sensitivity to 11 drugs and isolate 21,062 (RT078) carried distinct drug-resistance genes and loss of numerous flagellum-related genes.

CONCLUSIONS

We concluded that capillary electrophoresis based PCR-ribotyping is important for confirming RT078. Furthermore, RT078 isolates displayed specific MGEs, indicating an independent evolutionary process. In the further study, we could testify these findings with more RT078 isolates of divergent origins.

Rescue fecal microbiota transplantation for antibiotic-associated diarrhea in critically ill patients

BACKGROUND

Antibiotic-associated diarrhea (AAD) is a risk factor for exacerbating the outcome of critically ill patients. Dysbiosis induced by the exposure to antibiotics reveals the potential therapeutic role of fecal microbiota transplantation (FMT) in these patients. Herein, we aimed to evaluate the safety and potential benefit of rescue FMT for AAD in critically ill patients.

METHODS

A series of critically ill patients with AAD received rescue FMT from Chinese fmtBank, from September 2015 to February 2019. Adverse events (AEs) and rescue FMT success which focused on the improvement of abdominal symptoms and post-ICU survival rate during a minimum of 12 weeks follow-up were assessed.

RESULTS

Twenty critically ill patients with AAD underwent rescue FMT, and 18 of them were included for analysis. The mean of Acute Physiology and Chronic Health Evaluation (APACHE) II scores at intensive care unit (ICU) admission was 21.7 ± 8.3 (range 11-37). Thirteen patients received FMT through nasojejunal tube, four through gastroscopy, and one through enema. Patients were treated with four (4.2 ± 2.1, range 2-9) types of antibiotics before and during the onset of AAD. 38.9% (7/18) of patients had FMT-related AEs during follow-up, including increased diarrhea frequency, abdominal pain, increased serum amylase, and fever. Eight deaths unrelated to FMT occurred during follow-up. One hundred percent (2/2) of abdominal pain, 86.7% (13/15) of diarrhea, 69.2% (9/13) of abdominal distention, and 50% (1/2) of hematochezia were improved after FMT. 44.4% (8/18) of patients recovered from abdominal symptoms without recurrence and survived for a minimum of 12 weeks after being discharged from ICU.

CONCLUSION

In this case series studying the use of FMT in critically ill patients with AAD, good clinical outcomes without infectious complications were observed. These findings could potentially encourage researchers to set up new clinical trials that will provide more insight into the potential benefit and safety of the procedure in the ICU.

TRIAL REGISTRATION

ClinicalTrials.gov, Number NCT03895593 . Registered 29 March 2019 (retrospectively registered).

Antibiotic resistance of clinical isolates of Clostridioides difficile in China and its association with geographical regions and patient age

It is known that antibiotic usage is associated with the development of Clostridioides difficile infection (CDI), especially clindamycin, third-generation cephalosporins, and fuoroquinolones. Antibiotic resistance rates to many antibiotics varies a lot by study. We performed a study focused on antibiotic resistance in clinical isolates of C. difficile from more widespread geographic regions across China. Of 319 C. difficile isolates tested against 11 antibiotics, 313 (98.1%) were resistant to at least one antibiotic. The highest rate of resistance was to ciprofloxacin, clindamycin, and erythromycin across all age groups, similar to previous studies. However, all isolates were susceptible to metronidazole and vancomycin. Overall the resistance rate to tested antibiotics was lower than other reports in China except for chloramphenicol and meropenem. Genotype ST37/RT017 in clade 4 was resistant to more antibiotics than other types. Unexpectedly, RT078 isolates in this study were susceptible to almost all tested antibiotics. In addition, the proportion of multi-drug resistant (MDR) isolates observed (17%) in this study was much lower than several European studies (up to 55%) and a previous study in China (78%). Although isolates from patients aged between 65 and 85 were more resistant to antibiotics in comparison to other age groups, MDR isolates were still detected in children below 2-years of age. The highest percentage of MDR isolates was determined in South China, an area that is most developed economically. The clade 4, RT017 (ST37) has been associated with outbreaks in Europe and North America and is responsible for most C. difficile infections (CDIs) in Asia. In addition, RT017 is often clindamycin and fluoroquinolone resistant. This study provided a relatively comprehensive description of antibiotic resistance of C. difficile in China, and further elucidates the epidemiology and antibiotic resistance of clinical isolates of C. difficile in China at a national level.

Integrated genomic epidemiology and phenotypic profiling of Clostridium difficile across intra-hospital and community populations in Colombia

Clostridium difficile, the causal agent of antibiotic-associated diarrhea, has a complex epidemiology poorly studied in Latin America. We performed a robust genomic and phenotypic profiling of 53 C. difficile clinical isolates established from diarrheal samples from either intrahospital (IH) or community (CO) populations in central Colombia. In vitro tests were conducted to evaluate the cytopathic effect, the minimum inhibitory concentration of ten antimicrobial agents, the sporulation efficiency and the colony forming ability. Eleven different sequence types (STs) were found, the majority present individually in each sample, however in three samples two different STs were isolated. Interestingly, CO patients were infected with STs associated with hypervirulent strains (ST-1 in Clade-2). Three coexistence events (two STs simultaneously detected in the same sample) were observed always involving ST-8 from Clade-1. A total of 2,502 genes were present in 99% of the isolates with 95% of identity or more, it represents a core genome of 28.6% of the 8,735 total genes identified in the set of genomes. A high cytopathic effect was observed for the isolates positive for the two main toxins but negative for binary toxin (TcdA+/TcdB+/CDT- toxin production type), found only in Clade-1. Molecular markers conferring resistance to fluoroquinolones (cdeA and gyrA) and to sulfonamides (folP) were the most frequent in the analyzed genomes. In addition, 15 other markers were found mostly in Clade-2 isolates. These results highlight the regional differences that C. difficile isolates display, being in this case the CO isolates the ones having a greater number of accessory genes and virulence-associated factors.

Independent Microevolution Mediated by Mobile Genetic Elements of Individual Clostridium difficile Isolates from Clade 4 Revealed by Whole-Genome Sequencing

Mobile genetic elements play a key role in the continuing evolution of Clostridium difficile, resulting in the emergence of new phenotypes for individual isolates. On the basis of whole-genome sequencing analysis, we comprehensively explored transposons, CRISPR, prophage, and genetic sites for drug resistance within clade 4 C. difficile isolates with different sequence types. Great diversity in MGEs and a high rate of multidrug resistance were found within this clade, including new transposons, Tn4453a/b with aac(6′) aph(2′′) instead of catD, and a relatively high rate of prophage-carried CRISPR arrays. These findings provide important new insights into the mechanism of genome remodeling within clade 4 and offer a new method for typing and tracing the origins of closely related isolates.

Horizontal gene transfer of mobile genetic elements (MGEs) accounts for the mosaic genome of Clostridium difficile, leading to acquisition of new phenotypes, including drug resistance and reconstruction of the genomes. MGEs were analyzed according to the whole-genome sequences of 37 C. difficile isolates with a variety of sequence types (STs) within clade 4 from China. Great diversity was found in each transposon even within isolates with the same ST. Two novel transposons were identified in isolates ZR9 and ZR18, of which approximately one third to half of the genes showed heterogenous origins compared with the usual intestinal bacterial genes. Most importantly, catD, known to be harbored by Tn4453a/b, was replaced by aac(6′) aph(2′′) in isolates 2, 7, and 28. This phenomenon illustrated the frequent occurrence of gene exchanges between C. difficile and other enterobacteria with individual heterogeneity. Numerous prophages and CRISPR arrays were identified in C. difficile isolates of clade 4. Approximately 20% of spacers were located in prophage-carried CRISPR arrays, providing a new method for typing and tracing the origins of closely related isolates, as well as in-depth studies of the mechanism underlying genome remodeling. The rates of drug resistance were obviously higher than those reported previously around the world, although all isolates retained high sensitivity to vancomycin and metronidazole. The increasing number of C. difficile isolates resistant to all antibiotics tested here suggests the ease with which resistance is acquired in vivo. This study gives insights into the genetic mechanism of microevolution within clade 4.

IMPORTANCE Mobile genetic elements play a key role in the continuing evolution of Clostridium difficile, resulting in the emergence of new phenotypes for individual isolates. On the basis of whole-genome sequencing analysis, we comprehensively explored transposons, CRISPR, prophage, and genetic sites for drug resistance within clade 4 C. difficile isolates with different sequence types. Great diversity in MGEs and a high rate of multidrug resistance were found within this clade, including new transposons, Tn4453a/b with aac(6′) aph(2′′) instead of catD, and a relatively high rate of prophage-carried CRISPR arrays. These findings provide important new insights into the mechanism of genome remodeling within clade 4 and offer a new method for typing and tracing the origins of closely related isolates.

Molecular Characterization of Clostridium difficile Isolates in China From 2010 to 2015

Clostridium difficile infection (CDI) has become a worldwide public health problem causing high mortality and a large disease burden. Molecular typing and analysis is important for surveillance and infection control of CDI. However, molecular characterization of C. difficile across China is extremely rare. Here, we report on the toxin profiles, molecular subtyping with multilocus sequence typing (MLST) and PCR ribotyping, and epidemiological characteristics of 199 C. difficile isolates collected between 2010 through 2015 from 13 participating centers across China. We identified 35 STs and 27 ribotypes (RTs) among the 199 C. difficile isolates: ST35 (15.58%), ST3 (15.08%), ST37 (12.06%), and RT017 (14.07%), RT001 (12.06%), RT012 (11.56%) are the most prevalent. One isolate with ST1 and 8 isolates with ST 11 were identified. We identified a new ST in this study, denoted ST332. The toxin profile tcdA⁺tcdB⁺tcdC⁺tcdR⁺tcdE⁺CDT^- (65.83%) was the predominant profile. Furthermore, 11 isolates with positive binary toxin genes were discovered. According to the PCR ribotyping, one isolate with RT 027, and 6 isolates with RT 078 were confirmed. The epidemiological characteristics of C. difficile in China shows geographical differences, and both the toxin profile and molecular types exhibit great diversity across the different areas.