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.

Transcriptomic analysis of the ΔPaLoc mutant of Clostridioides difficile and verification of its toxicity / 中华预防医学杂志

Objective: Comparative analyses of wild-type Clostridioides difficile 630 (Cd630) strain and pathogenicity locus (PaLoc) knockout mutant (ΔPaLoc) by using RNA-seq technology. Analysis of differential expression of Cd630 wild-type strain and ΔPaLoc mutant strain and measurement of its cellular virulence changes. Lay the foundation for the construction of an toxin-attenuated vaccine strain against Clostridioides difficile. Methods: Analysis of Cd630 and ΔPaLoc mutant strains using high-throughput sequencing (RNA-seq). Clustering differentially expressed genes and screening differentially expressed genes by DESeq software. Further analysis of differential genes using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Finally, cytotoxicity assays of ΔPaLoc and Cd630 strains were performed in the African monkey kidney epithelial cell (Vero) and the human colonic cell (Caco-2) lines. Results: The transcriptome data showed that the ΔPaLoc mutant toxin genes tcdA and tcdB were not transcribed. Compared to the wild-type strain, CD630_36010, CD630_020910,CD630_02080 and cel genes upregulated 17.92,11.40,8.93 and 7.55 fold, respectively. Whereas the hom2 (high serine dehydrogenase), the CD630_15810 (spore-forming protein), CD630_23230 (zinc-binding dehydrogenase) and CD630_23240 (galactitol 1-phosphate 5-dehydrogenase) genes were down-regulated by 0.06, 0.075, 0.133 and 0.183 fold, respectively. The GO and KEGG enrichment analyses showed that the differentially transcribed genes in ΔPaLoc were enriched in the density-sensing system, ABC transport system, two-component system, phosphotransferase (PTS) system, and sugar metabolism pathway, as well as vancomycin resistance-related pathways. Cytotoxicity assays showed that the ΔPaLoc mutant strain lost its virulence to Vero and Caco-2 cells compared to the wild-type Cd630 strain. Conclusion: Transcriptional sequencing analysis of the Cd630 and ΔPaLoc mutant strains showed that the toxin genes were not transcribed. Those other differential genes could provide a reference for further studies on the physiological and biochemical properties of the ΔPaLoc mutant strain. Cytotoxicity assays confirmed that the ΔPaLoc mutant lost virulence to Vero and Caco-2 cells, thus laying the foundation for constructing an toxin-attenuated vaccine strain against C. difficile.

Assessing risk factors, mortality, and healthcare utilization associated with Clostridioides difficile infection in four Latin American countries

ABSTRACT Background: Clostridioides difficile infection (CDI) is the most common cause of healthcare-associated infections in Western countries. Risk factors, mortality, and healthcare utilization for CDI in Latin America are poorly understood. This study assessed risk factors and burden associated with nosocomial CDI in four Latin American countries. Methods: This retrospective, case-control study used databases and medical records from 8 hospitals in Argentina, Brazil, Chile, and Mexico to identify nosocomial CDI cases from 2014 − 2017. Cases were patients aged ≥18 years with diarrhea and a positive CDI test ≥72 h after hospital admission. Two controls (without diarrhea; length of hospital stay [LOS] ≥3 days; admitted ±14 days from case patient; shared same ward) were matched to each case. CDI-associated risk factors were assessed by univariate and multivariable analyses. CDI burden (LOS, in-hospital mortality) was compared between cases and controls. Results: The study included 481 cases and 962 controls. Mean age and sex were similar between cases and controls, but mean Charlson comorbidity index (4.3 vs 3.6; p< 0.001) and recent hospital admission (35.3% vs 18.8%; p< 0.001) were higher among cases. By multivariable analyses, CDI risk was associated with prior hospital admission within 3 months (odds ratio [OR], 2.08; 95% CI: 1.45, 2.97), recent antibiotic use (ie, carbapenem; OR, 2.85; 95% CI: 1.75, 4.64), acid suppressive therapy use (OR, 1.71; 95% CI: 1.14, 2.58), and medical conditions (ie, renal disease; OR, 1.48; 95% CI: 1.19, 1.85). In-hospital mortality rate (18.7% vs 6.9%; p< 0.001) and mean overall LOS (33.5 vs 18.8 days; p< 0.001) were higher and longer, respectively, in cases versus controls. Conclusion: Antibiotic exposure, preexisting medical conditions, and recent hospital admission were major risk factors for CDI in Argentina, Brazil, Chile, and Mexico. CDI was associated with increased in-hospital risk of death and longer LOS. These findings are consistent with published literature in Western countries.

Trasplante de microbiota fecal en la infección por Clostridioides difficile / Faecal microbiota transplantation for Clostridioides difficile infection

Resumen La infección por Clostridioides difficile (iCD) es la causa más frecuente de diarrea nosocomial. La primera línea terapéutica es la vancomicina asociada o no al metronidazol. En los últimos años se incrementó el número de fracasos terapéuticos con una mayor frecuencia de formas refractarias o recurrentes. El trasplante de microbiota fecal (TMF) ha surgido como una opción terapéutica para estos casos. Se evaluó la seguridad y la tasa de resolución empleando el TMF en un estudio observacional abierto y prospectivo de 21 pacientes con iCD recurrentes o refractarias internados entre los años 2016 y 2019. La edad media fue de 76.5 años (33-92). Diez presentaron una forma recurrente y 11 una refractaria, 18 fueron graves y 3 fulminantes. En 20 casos el TMF se administró por la vía digestiva alta y en uno por presentar íleo se utilizó la vía baja. Se empleó TMF de heces frescas en un caso y el resto recibió muestras congeladas de un banco de microbiota. Veinte pacientes (95.2%) tuvieron respuesta terapéutica favorable sin presentar recurrencias. Un caso recurrente, con osteomielitis y falla multiorgánica, no tuvo resolución tras dos TMF. La respuesta fue similar en las formas recurrentes y refractarias. Siete pacientes (31%) tuvieron efectos adversos leves y autolimitados. El TMF ha demostrado una alta eficacia como tratamiento de rescate de las formas graves de iCD, con escasos y leves efectos adversos. Contar con un banco de microbiota fecal resulta fundamental para disponer de este recurso terapéutico oportunamente.

Abstract Clostridiodes difficile infection (CDi) is the most common cause of nosocomial diarrhea. Vancomycin, associated or not to metronidazol, is the treatment of choice. However, the rate of treatment failure has increased over the last years and fecal microbiota transplantation (FMT) has emerged as a therapeutic option. To evaluate safety and efficacy of FMT were enrolled 21 hospitalized patients with refractory or recurrent CDi between 2016 and 2019. Fourteen (66%) patients were men and the average age was 76.5 years (range 33-92). Ten had recurrent and 11 refractory CDi, and 18 presented severe and 3 fulminant clinical forms. In 20 cases the FMT was delivered through a nasojejunal tube and in one patient with ileo via enema infusion. Frozen fecal from a stool bank were administered in 20 and in the remaining was used fresh fecal matter. The rate of resolution was observed in 20 patients (95.2%) and none presented recurrence. The response rate was similar in recurrent or refractory forms (9/10 vs 11/11 respectively). One patient with osteomyelitis and multiple organ failure received 2 FMT without response and died. Seven patients (31%) presented mild and self-limited adverse effects. FMT has shown a high efficacy as rescue treatment in cases with refractory or recurrent CDi regardless of severity, with mild side effects. Availability of a stool banks provide reliable, timely and equitable access to FMT for CDi.

COVID-19 and coinfection with Clostridioides (Clostridium) difficile in an infant with gastrointestinal manifestation / COVID-19 e coinfecção por Clostridioides (Clostridium) difficile em lactente com manifestações gastrintestinais

ABSTRACT We report the clinical case of an infant with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with gastrointestinal signs and symptoms, predominantly vomiting. The patient also had colic, poor feeding, mild diarrhea and mild rhinorrhea without fever. The child had evidence of altered coagulation, increased interleukin 10, moderate dehydration and she was admitted to the pediatric intensive care unit. Simultaneously, the patient was diagnosed as Clostridioides difficile infection, which possibly may have facilitated the persistence of SARS-CoV-2 in feces, for more than 27 days, even after the nasopharyngeal test turned negative. This coinfection might exacerbate the gastrointestinal signs and symptoms and increased the possibility of fecal-oral transmission of SARS-CoV-2 and Clostridioides . The patient was breastfed and received complementary infant formula, hydrated with intravenous fluid, and was discharged without complications, 4 days after admission.

RESUMO Relatamos o caso clínico de uma lactente com infecção por coronavírus da síndrome respiratória aguda grave 2 (SARS-CoV-2) com sinais e sintomas gastrintestinais - predominantemente vômitos. A paciente apresentou, adicionalmente, cólica, dificuldade para mamar, evacuações amolecidas e rinorreia leve, sem febre. Houve evidências de alterações da coagulação, aumento de interleucina 10 e desidratação moderada, que justificaram internação na unidade de terapia intensiva. Simultaneamente, a paciente foi diagnosticada com infecção por Clostridioides difficile , que pode ter facilitado a persistência do SARS-CoV-2 nas fezes por mais de 27 dias, mesmo após negativação do teste nasofaríngeo. Essa coinfecção pode ter exacerbado os sinais e sintomas gastrintestinais e aumentado a possibilidade da transmissão do SARS-CoV-2 e Clostridioides . A paciente foi mantida em aleitamento materno e complemento com fórmula infantil, recebeu hidratação intravenosa e teve alta hospitalar, sem complicações, após 4 dias de internação.