The emergence of Clostridium difficile PCR-ribotype 001 in Slovakia

Clostridioides difficile Ribotype 027 (RT027) Outbreak Investigation Due to the Emergence of Rifampicin Resistance Using Multilocus Variable-Number Tandem Repeat Analysis (MLVA)

Objective

The aim of this study was Clostridioides difficile outbreak investigation due to the emergence of rifampicin resistant ribotype 027 (RT 027) fecal isolates from patients of Polish tertiary care hospital between X. 2017 and II. 2018 using multilocus variable tandem repeat analysis (MLVA).

Materials and Methods

Twenty-nine C. difficile fecal isolates from patients of tertiary care hospital in Southern Poland were ribotyped and analyzed by MLVA. Multiplex PCR (mPCR) for genes encoding GDH (gluD), toxins A (tcdA)/ B (tcdB), 16S rDNA and binary toxin genes (ctdA and ctdB) was performed. The antibiotic susceptibility profile was determined by E-test.

Results

The A, B and binary toxins encoding genes were detected in all 29 C. difficile strains which were sensitive to metronidazole, vancomycin and were resistant to erythromycin, clindamycin, and moxifloxacin; resistance to imipenem demonstrated 97%, to rifampicin – 45% isolates. C. difficile strains could be grouped by MLVA into 5 distinct clusters, and the largest cluster II contains 16 strains. The comparison of rifampicin GM MIC of cluster II (n=16 strains) with all others (n=13) showed that strains from clusters I, III, IV and V possessed significantly (p <0.005) higher GM MIC and were more resistant to rifampicin.

Conclusion

MLVA analysis proved transmission and recognized outbreak due to multidrug-resistant RT 027 C. difficile among patients of tertiary care hospital in Southern Poland. The reason for this is probably the widespread occurrence of spores in the hospital environment, which includes, among others, neglect of hygienic procedures and epidemic supervision. High resistance to imipenem (97%) and to rifampicin (45%) among C. difficile RT 027 Silesian isolates is threatening and requires further studies to elucidate this phenomenon.

Diagnostic Methods of Clostridioides difficile Infection and Clostridioides difficile Ribotypes in Studied Sample

BACKGROUND

Clostridioides (Clostridium) difficile is the most common nosocomial pathogen and antibiotic-related diarrhea in health-care facilities. Over the last few years, there was an increase in the incidence rate of C. difficile infection cases in Slovakia. In this study, the phenotypic (toxigenicity, antimicrobial susceptibility) and genotypic (PCR ribotypes, genes for binary toxins) patterns of C. difficile isolates from patients with CDI were analyzed, from July to August 2016, taken from hospitals in the Horne Povazie region of northern Slovakia. The aim of the study was also to identify hypervirulent strains (e.g., the presence of RT027 or RT176).

METHODS

The retrospective analysis of biological samples suspected of CDI were analyzed by GDH, anaerobic culture, enzyme immunoassay on toxins A/B, multiplex "real-time" PCR and PCR capillary-based electrophoresis ribotyping, and by MALDI TOF MS.

RESULTS

C. difficile isolates (n = 44) were identified by PCR ribotyping, which revealed five different ribotypes (RT001, 011, 017, 081, 176). The presence of hypervirulent RT027 was not identified. The C. difficile isolates (RT001, 011, 081, 176) were susceptible to metronidazole and vancomycin. One isolate RT017 had reduced susceptibility to vancomycin. A statistically significant difference between the most prevalent PCR ribotypes, RT001 and RT176, regarding variables such as albumin, CRP, creatinine, the length of hospitalization (p = 0.175), and glomerular filtration (p = 0.05) was not found.

CONCLUSION

The results of PCR capillary-based electrophoresis ribotyping in the studied samples showed a high prevalence of RT176 and 001.

Molecular epidemiology of predominant and emerging Clostridioides difficile ribotypes

There has been an increase in the incidence and severity of Clostridioides difficile infection (CDI) worldwide, and strategies to control, monitor, and diminish the associated morbidity and mortality have been developed. Several typing methods have been used for typing of isolates and studying the epidemiology of CDI; serotyping was the first typing method, but then was replaced by pulsed-field gel electrophoresis (PFGE). PCR ribotyping is now the gold standard method; however, multi locus sequence typing (MLST) schemes have been developed. New sequencing technologies have allowed comparing whole bacterial genomes to address genetic relatedness with a high level of resolution and discriminatory power to distinguish between closely related strains. Here, we review the most frequent C. difficile ribotypes reported worldwide, with a focus on their epidemiology and genetic characteristics.

New Approaches to Diagnostics of C.Difficile Infection

Introduction: Clostridium difficile infection (CDI) is the most common infectious cause of diarrhoea in hospitalised patients. It is a severe issue with increasing incidence in healtcare facilities and commmunities. Early and appropriate testing of CDI is very imortant. There are many different approaches that can be used in the CDI laboratory diagnostics. Recently performed studies evaluated diagnostic algorithms to optimize laboratory CDI diagnostics. The aim of the work was to implement an optimal algorithm of testing methods in CDI diagnostics.

Materials and methods: The retrospective analysis of patients’ samples suspected on CDI was carried out in 2017. The data was analysed from the Laboratory Klinicka Biochemia in Zilina. The application of ESCMID re -commendation criteria for algorithm of testing, together with procedures in laboratory practice was carried out.

Results: The analysis of the data showed that the applied algorithm or testing in CDI and highlighted the importance of preanalytic phase, and the evaluation of testing methods and results, together with clinical findings. Two- and three- step algorithm together with cultivation methods were applied. 87,6% of samples could be eva -luated with positive or negative results according to the 2-step algorhitm. Further samples were assessed and tested by ELISA test or PCR method.

Conclusion: CDI represents a significant burden in healthcare facilities. An early diagnostics and interpretation helps to start the early treatment and helps in surveillence of the infection.

The emergence of Clostridium difficile ribotypes 027 and 176 with a predominance of the Clostridium difficile ribotype 001 recognized in Slovakia following the European standardized Clostridium difficile infection surveillance of 2016

AIM

To obtain standardized epidemiological data for Clostridium difficile infection (CDI) in Slovakia.

METHODS

Between October and December 2016, 36 hospitals in Slovakia used the European Centre for Disease Prevention and Control (ECDC) Clostridium difficile infection (CDI) surveillance protocol.

RESULTS

The overall mean CDI incidence density was 2.8 (95% confidence interval 1.9-3.9) cases per 10 000 patient-days. Of 332 CDI cases, 273 (84.9%) were healthcare-associated, 45 (15.1%) were community-associated, and 14 (4.2%) were cases of recurrent CDI. A complicated course of CDI was reported in 14.8% of cases (n=51). CDI outcome data were available for 95.5% of cases (n=317). Of the 35 patients (11.1%) who died, 34 did so within 30 days after their CDI diagnosis. Of the 78 isolates obtained from 12 hospitals, 46 belonged to PCR ribotype 001 (59.0%; 11 hospitals) and 23 belonged to ribotype 176 (29.5%; six hospitals). A total of 73 isolates (93.6%) showed reduced susceptibility to moxifloxacin (ribotypes 001 and 176; p< 0.01). A reduced susceptibility to metronidazole was observed in 13 isolates that subsequently proved to be metronidazole-susceptible when, after thawing, they were retested using the agar dilution method. No reduced susceptibility to vancomycin was found.

CONCLUSIONS

These results show the emergence of C. difficile ribotypes 027 and 176 with a predominance of ribotype 001 in Slovakia in 2016. Given that an almost homogeneous reduced susceptibility to moxifloxacin was detected in C. difficile isolates, this stresses the importance of reducing fluoroquinolone prescriptions in Slovak healthcare settings.

Virulence Factors of Clostridioides (Clostridium) difficile Linked to Recurrent Infections

From 20 to 30% of Clostridioides (Clostridium) difficile infection (CDI), patients might develop recurrence of the infection (RCDI) and, after the first recurrence, the risk of further episodes increases up to 60%. Several bacterial virulence factors have been associated with RCDI, including the elevated production of toxins A and B, the presence of a binary toxin CDT, and mutations in the negative regulator of toxin expression, tcdC. Additional factors have shown to regulate toxin production and virulence in C. difficile in RCDI, including the accessory-gene regulator agr, which acts as a positive switch for toxin transcription. Furthermore, adhesion and motility-associated factors, such as Cwp84, SlpA, and flagella, have shown to increase the adhesion efficiency to host epithelia, cell internalization, and the formation of biofilm. Finally, biofilm confers to C. difficile protection from antibiotics and acts as a reservoir for spores that allow the persistence of the infection in the host. In this review, we describe the key virulence factors of C. difficile that have been associated with recurrent infections.

A pilot study in Serbia by European Clostridium difficile Infection Surveillance Network

Clostridium (Clostridioides) difficile infections (CDIs) are among the most frequent healthcare-associated infections in Serbia. In 2013, Serbia participated in the European Clostridium difficile Infection Surveillance Network (ECDIS-Net) who launched a pilot study to enhance laboratory capacity and standardize surveillance for CDI. Two clinics of Clinical Center of Serbia [Clinic for Infectious and Tropical Diseases (CITD) and Clinic of Orthopedic Surgery and Traumatology (COT)] from Belgrade and one general hospital from another metropolitan area of Serbia, Užice, participated. During a period of 3 months in 2013, all patients with diagnosed CDI were included. The CDI incidence rates in CITD, COT, and General Hospital Užice were 19.0, 12.2, and 3.9 per 10,000 patient-days, respectively. In total, 49 patients were enrolled in the study with average age of 72 years. A complicated course of CDI was found in 14.3% of all patients. Six (12.2%) of 49 patients died, but not attributable to CDI. Of 39 C. difficile isolates, available for ribotyping, 78.9% belonged to ribotype 027; other PCR ribotypes were 001, 015, 002, 005, 010, 014, and 276. Antimicrobial susceptibility testing revealed low levels of MIC50 and MIC90 for metronidazole (0.5 μg/ml both) and vancomycin (0.25 and 0.5 μg/ml), while 28 strains of ribotype 027 were resistant to moxifloxacin with MIC ≥4 μg/ml. National surveillance is important to obtain more insight in the epidemiology of CDI and to compare the results with other European countries. This study by ECDIS-Net gives bases for a national surveillance of CDI in Serbia.

Molecular epidemiologic study of Clostridium difficile infections in university hospitals: Results of a nationwide study in Japan

We conducted a nationwide molecular epidemiological study of Clostridium difficile infection (CDI) in Japan investigated the correlation between the presence of binary toxin genes and CDI severity. This is the first report on molecular epidemiological analyses for CDI in multiple university hospitals in Japan, to our knowledge. We examined 124,484 hospitalized patients in 25 national and public university hospitals in Japan between December 2013 and March 2014, investigating antimicrobial susceptibilities and toxin-related genes for C. difficile isolates from stools. Epidemiological genetic typing was performed by PCR-ribotyping and repetitive sequence-based (rep)-PCR to examine the genetic similarities. The results detected toxin A-positive, toxin B-positive, binary toxin-negative (A⁺B⁺CDT^-) detected from 135 isolates (80.8%) and toxin A-negative, toxin B-positive, binary toxin-negative (A^-B⁺CDT^-) in 23 (13.8%). Toxin A-positive, toxin B-positive, and binary toxin-positive (A⁺B⁺CDT⁺) were seen in 9 isolates (5.4%). Vancomycin (n = 81, 37.7%) or metronidazole (n = 88, 40.9%) therapies were undertaken in analyzed cases. Ribotypes detected from isolates were 017/subgroup 1, 070, 078, 126, 176, 449, 475/subgroup 1, 499, 451, 566 and newtypes. Rep-PCR classified 167 isolates into 28 cluster groups including 2-15 isolates. In addition, 2 pairs of strains isolated from different institutions belonged to the same clusters. Seven out of 9 (77.8%) of the patients with binary toxin producing strains had "mild to moderate" outcome in evaluated symptoms. In conclusion, we found that binary toxin did not show regional specificity and had no relevance to severity of CDI.

The predominance and clustering of Clostridioides (Clostridium) difficile PCR ribotype 001 isolates in three hospitals in Eastern Slovakia, 2017

This study aimed to implement a toxigenic culture as an optional third diagnostic step for glutamate dehydrogenase (GDH)-positive and toxin A/B-negative diarrheal stool samples into a diagnostic algorithm for Clostridioides (Clostridium) difficile infection (CDI), and to characterise C. difficile isolates for epidemiological purposes. During the 5-month study, 481 diarrhoeal stool samples from three Slovak hospitals were investigated and 66 non-duplicated GDH-positive stool samples were found. Of them, 36 were also toxin A/B-positive. Twenty-three GDH-positive and toxin A/B-negative stool samples were shown subsequently to be positive following toxigenic culture (TC). Molecular characterisation of C. difficile isolates showed the predominance of PCR ribotype (RT) 001 (n = 37, 56.1%) and the occurrence of RT 176 (n = 3, 4.5%). C. difficile RT 001 isolates clustered to eight clonal complexes (CCs) using multiple-locus variable-number tandem repeats analysis (MLVA). Interestingly, one third of RT 001 isolates clustering in these CCs were cultured from toxin A/B-negative stool samples. Our observations highlight the need of use multiple step diagnostic algorithm in CDI diagnosis in order to detect all CDI cases and to avoid the spread of C. difficile in healthcare settings.

New insights into transmission of Clostridium difficile infection-narrative review

BACKGROUND

Traditionally, Clostridium difficile has been considered a typical healthcare-associated pathogen-that is, one transmitted within healthcare facilities and thus prevented by implementation of standard infection control measures. Recently this concept has been challenged by studies suggesting a relevant role for community acquisition of C. difficile.

AIMS

To discusses the current literature, compiled during the last decade, reporting on sources of acquisition of C. difficile and subsequent transmission.

SOURCES

The databases PubMed, Medline, Embase and the Cochrane Database were searched for articles published from 1 January 2007 to 30 June 2017 reporting on possible transmission pathways of C. difficile and/or suggesting a source of acquisition of C. difficile. All study types reporting on adult populations were considered; case reports and series were excluded. The PRISMA guidelines for the reporting of systematic reviews were followed.

CONTENT

Among 24 original articles included, 63% report on transmission of C. difficile in healthcare settings and 37% investigate sources and transmission of C. difficile in the community. Contact with symptomatic carriers (53.3%), the hospital environment (40.0%) and asymptomatic carriers (20%) were the most commonly reported transmission pathways within healthcare settings. The leading sources for acquisition of C. difficile in the community include direct contact with symptomatic and asymptomatic carriers in the community, including infants (30%) and residents of long-term non-acute care facilities (30%), followed by contact with contaminated environments in outpatient care settings (20%) and exposure to livestock or livestock farms (20%).

IMPLICATIONS

In healthcare settings, future control efforts may need to focus on extending cleaning and disinfection procedures beyond the immediate surroundings of symptomatic carriers. Potential targets to prevent acquisition of C. difficile in the community include household settings, long-term care facilities and outpatient settings, while the role of livestock in entertaining transmission requires further investigation.

Direct PCR-Ribotyping of Clostridium difficile

PCR-ribotyping, a method based on heterogeneity of ribosomal intergenic spacer region, is the preferred method for genotyping of Clostridium difficile. Standardly used procedure for PCR-ribotyping is culturing of C. difficile from fecal samples and subsequent typing. In this chapter, we describe a modified PCR-ribotyping method for direct detection of PCR-ribotypes directly in total stool DNA extract, without prior need to isolate C. difficile.

Molecular characterisation of Czech Clostridium difficile isolates collected in 2013-2015

Clostridium difficile is a leading nosocomial pathogen and molecular typing is a crucial part of monitoring its occurrence and spread. Over a three-year period (2013-2015), clinical C. difficile isolates from 32 Czech hospitals were collected for molecular characterisation. Of 2201 C. difficile isolates, 177 (8%) were non-toxigenic, 2024 (92%) were toxigenic (tcdA and tcdB) and of these, 677 (33.5%) carried genes for binary toxin production (cdtA, cdtB). Capillary-electrophoresis (CE) ribotyping of the 2201 isolates yielded 166 different CE-ribotyping profiles, of which 53 were represented by at least two isolates for each profile. Of these, 29 CE-ribotyping patterns were common to the Leeds-Leiden C. difficile reference strain library and the WEBRIBO database (83.7% isolates), and 24 patterns were recognized only by the WEBRIBO database (11.2% isolates). Isolates belonging to these 53 CE-ribotyping profiles comprised 94.9% of all isolates. The ten most frequent CE-ribotyping profiles were 176 (n=588, 26.7%), 001 (n=456, 20.7%), 014 (n=176, 8%), 012 (n=127, 5.8%), 017 (n=85, 3.9%), 020 (n=68, 3.1%), 596 (n=55, 2.5%), 002-like (n=45, 2.1%), 010 (n=35, 1.6%) and 078 (n=34, 1.6%). Multi-locus sequence typing (MLST) of seven housekeeping genes performed in one isolate of each of 53 different CE-ribotyping profiles revealed 40 different sequence types (STs). We conclude that molecular characterisation of Czech C. difficile isolates revealed a high diversity of CE-ribotyping profiles; the prevailing RTs were 001 (20.7%) and 176 (027-like, 26.7%).

Clostridium difficile PCR ribotypes 001 and 176 – the common denominator of C. difficile infection epidemiology in the Czech Republic, 2014

In 2014, 18 hospitals in the Czech Republic participated in a survey of the incidence of Clostridium difficile infections (CDI) in the country. The mean CDI incidence was 6.1 (standard deviation (SD):7.2) cases per 10,000 patient bed-days and 37.8 cases (SD: 41.4) per 10,000 admissions. The mean CDI testing frequency was 39.5 tests (SD: 25.4) per 10,000 patient bed-days and 255.8 tests (SD: 164.0) per 10,000 admissions. A total of 774 C. difficile isolates were investigated, of which 225 (29%) belonged to PCR ribotype 176, and 184 isolates (24%) belonged to PCR ribotype 001. Multilocus variable-number tandem repeat analysis (MLVA) revealed 27 clonal complexes formed by 84% (190/225) of PCR ribotype 176 isolates, and 14 clonal complexes formed by 77% (141/184) of PCR ribotype 001 isolates. Clonal clusters of PCR ribotypes 176 and 001 were observed in 11 and 7 hospitals, respectively. Our data demonstrate the spread of two C. difficile PCR ribotypes within 18 hospitals in the Czech Republic, stressing the importance of standardising CDI testing protocols and implementing mandatory CDI surveillance in the country.