The fliL gene significantly affects the motility and sporulation abilities of Clostridioides difficile / 生物工程学报

Flagella are the main motility structure of Clostridioides difficile that affects the adhesion, colonization, and virulence of C. difficile in the human gastrointestinal tract. The FliL protein is a single transmembrane protein bound to the flagellar matrix. This study aimed to investigate the effect of the FliL encoding gene flagellar basal body-associated FliL family protein (fliL) on the phenotype of C. difficile. The fliL gene deletion mutant (ΔfliL) and its corresponding complementary strains (: : fliL) were constructed using allele-coupled exchange (ACE) and the standard molecular clone method. The differences in physiological properties such as growth profile, antibiotic sensitivity, pH resistance, motility, and spore production ability between the mutant and wild-type strains (CD630) were investigated. The ΔfliL mutant and the : : fliL complementary strain were successfully constructed. After comparing the phenotypes of strains CD630, ΔfliL, and : : fliL, the results showed that the growth rate and maximum biomass of ΔfliL mutant decreased than that of CD630. The ΔfliL mutant showed increased sensitivity to amoxicillin, ampicillin, and norfloxacin. Its sensitivity to kanamycin and tetracycline antibiotics decreased, and the antibiotic sensitivity partially returned to the level of CD630 strain in the : : fliL strain. Moreover, the motility was significantly reduced in the ΔfliL mutant. Interestingly, the motility of the : : fliL strain significantly increased even when compared to that of the CD630 strain. Furthermore, the pH tolerance of the ΔfliL mutant significantly increased or decreased at pH 5 or 9, respectively. Finally, the sporulation ability of ΔfliL mutant reduced considerably compared to the CD630 strain and recovered in the : : fliL strain. We conclude that the deletion of the fliL gene significantly reduced the swimming motility of C. difficile, suggesting that the fliL gene is essential for the motility of C. difficile. The fliL gene deletion significantly reduced spore production, cell growth rate, tolerance to different antibiotics, acidity, and alkalinity environments of C. difficile. These physiological characteristics are closely related to the survival advantage in the host intestine, which is correlated with its pathogenicity. Thus, we suggested that the function of the fliL gene is closely related to its motility, colonization, environmental tolerance, and spore production ability, which consequently affects the pathogenicity of C. difficile.

Detection of vancomycin-resistant enterococci (VRE) in stool specimens submitted for Clostridium difficile toxin testing

Abstract The aim of this study was to determine the association between Clostridium difficile (C. difficile) and vancomycin-resistant Enterococcus (VRE) and efficacy of screening stools submitted for C. difficile toxin assay for prevalence of VRE. Between April 2012 and February 2014, 158 stool samples submitted for C. difficile toxin to the Marmara University Microbiology Laboratory, were included in the study. Stool samples were analyzed by enzyme immuno assay test; VIDAS (bioMerieux, France) for Toxin A&B. Samples were inoculated on chromID VRE (bioMerieux, France) and incubated 24 h at 37 °C. Manuel tests and API20 STREP (bioMerieux, France) test were used to identify the Enterococci species. After the species identification, vancomycin and teicoplanin MIC's were performed by E test and molecular resistance genes for vanA vs vanB were detected by polymerase chain reaction (PCR). Of the 158 stool samples, 88 were toxin positive. The prevalence of VRE was 17%(n:19) in toxin positives however, 11.4% in toxin negatives(n:70). All VRE isolates were identified as Enterococcus faecium. These results were evaluated according to Fischer's exact chi-square test and p value between VRE colonization and C. difficile toxin positivity was detected 0.047 (p < 0.05). PPV and NPV were 79% and 47% respectively. In our study, the presence of VRE in C. difficile toxin positives is statistically significant compared with toxin negatives (p < 0.05). Screening for VRE is both additional cost and work load for the laboratories. Therefore VRE screening among C. difficile toxin positive samples, will be cost effective for determination of high risk patients in the hospitals especially for developing countries.

Analysis of risk factors and clinical manifestations associated with Clostridium difficile disease in Serbian hospitalized patients

Abstract Clostridium difficile is the leading cause of infectious diarrhoea in hospitalized patients. The aim of this study was to determine the risk factors important for the development of hospital-acquired Clostridium difficile-associated disease and clinical manifestations of Clostridium difficile-associated disease. The clinical trial group included 37 hospitalized patients who were selected according to the inclusion criteria. A control group of 74 hospitalized patients was individually matched with cases based on hospital, age (within 4 years), sex and month of admission.Clostridium difficile-associated disease most commonly manifested as diarrhoea (56.76%) and colitis (32%), while in 8.11% of patients, it was diagnosed as pseudomembranous colitis, and in one patient, it was diagnosed as fulminant colitis. Statistically significant associations (p < 0.05) were found with the presence of chronic renal failure, chronic obstructive pulmonary disease, cerebrovascular accident (stroke) and haemodialysis. In this study, it was confirmed that all the groups of antibiotics, except for tetracycline and trimethoprim-sulfamethoxazole, were statistically significant risk factors for Clostridium difficile-associated disease (p < 0.05). However, it was difficult to determine the individual role of antibiotics in the development of Clostridium difficile-associated disease. Univariate logistic regression also found that applying antibiotic therapy, the duration of antibiotic therapy, administration of two or more antibiotics to treat infections, administering laxatives and the total number of days spent in the hospital significantly affected the onset of Clostridium difficile-associated disease (p < 0.05), and associations were confirmed using the multivariate model for the application of antibiotic therapy (p = 0.001), duration of antibiotic treatment (p = 0.01), use of laxatives (p = 0.01) and total number of days spent in the hospital (p = 0.001). In this study of patients with hospital-acquired diarrhoea, several risk factors for the development of Clostridium difficile-associated disease were identified.

Clostridium perfringens type A & antibiotic associated diarrhoea.

BACKGROUND & OBJECTIVE: Clostridium perfringens type A (CPA) isolates produce lethal necrotizing antigens and the heat resistant forms of the organism are associated with pathogenic outcome in humans. CPA has also been implicated in antibiotic associated diarrhoea (AAD). We therefore undertook this study to investigate the presence of CPA in stool samples of patients with AAD in a tertiary care setting in north India. METHODS: A total of 285 stool samples obtained from patients suspected for Clostridium difficile aetiology were examined for the presence of CPA antigens. Four sets of reagents (CP-I, CP-II, CP-III and CP- IV) comprising latex beads coated with polyvalent immune sera to 17 serotypes of heat resistant CPA were used in the study. Agglutination reaction was carried out using the reagents with the stool supernatants. RESULTS: Of the 285 stool samples tested, 25 (8.77%) were positive for at least one or more of the four polyvalent sets. Briefly, 48 per cent were positive for all the four sets, 12 per cent for 3 sets, 28 per cent for 2 sets and 12 per cent for only one set, indicating the prevalence of multiple serotypes of CPA. Twenty three (92%) of the 25 positive samples came from patients who were on antibiotics. C. difficile toxin was also present in 9 of 25 (36%) of the samples positive for CPA antigens. INTERPRETATION & CONCLUSION: In our setting, CPA could thus be associated with AAD either by itself or in synergy with C. difficile infection. Assessment of true burden of CPA associated AAD would be required to take appropriate steps for its control in our country.

Simultaneous assays for Clostridium difficile and faecal lactoferrin in ulcerative colitis.

Infectious agents may be one of the important factors in initiating or perpetuating ulcerative colitis. Increasing evidence has accumulated regarding the role of Clostridium difficile (C. difficile) infection in the exacerbation of ulcerative colitis. The present work was undertaken to study the implications of C. difficile toxin (CDT) and faecal lactoferrin (FL) positivity in patients with idiopathic ulcerative colitis (IUC) in a north Indian hospital. Ninety-four faecal samples from patients of IUC were processed for CDT and FL simultaneously. Clinical details of patients, including antibiotic intake in the past 6 weeks, were recorded. Eighty-one of the 94 patients (86.2%) had diarrhoea and 48 (51.1%) had received antibiotics. There was a statistically significant (p < 0.001) increase in the prevalence of diarrhoea among individuals receiving antibiotics. Twelve of the 94 samples (12.8%) were CDT positive while 16 were FL positive. No statistical significance (p > 0.05) was seen while comparing the positivity of CDT and FL in relation to the receipt of antibiotics. A statistically significant (p < 0.001) positive correlation was present between CDT and FL assays. FL positivity in IUC may depend on the intestinal inflammation precipitated by C. difficile infection.

Faecal lactoferrin assay as an adjunct to Clostridium difficile diarrhoea.

Inflammation is the hallmark of Clostridium difficile associated diarrhoea and lactoferrin is produced by inflammatory cells. The aim of this study was to find out whether faecal lactoferrin latex agglutination (FLLA) assay done simultaneously with Clostridium difficile toxin (CDT) assay would help in the diagnosis of C. difficile infection in paediatric patients. One hundred and fifty faecal samples were obtained from paediatric group of patients. Both FLLA and CDT assays were done in conjunction on these samples. The data were expressed by descriptive statistics. One hundred and nineteen patients received antibiotics while 31 did not receive it. Of the former group 89 (74.8%) had diarrhoea while 30 (25.2%) did not have it. No significant relationship (p=0.287) was seen between antibiotic usage and occurrence of diarrhoea. However, CDT positivity was seen to be influenced by prior antibiotic usage as 51 (42.9%) patients receiving antibiotics were CDT positive when compared to 4 (7.3%) of those who did not receive antibiotics (p=0.002). A highly statistically significant (p<0.001) relationship was seen between CDT and FLLA positivity. FLLA appears to be an useful adjunct for C. difficile associated intestinal diseases in children when both the tests are done simultaneously and when other enteropathogens causing inflammatory diarrhoeas are ruled out.