Molecular and Microbiological Characterization of Clostridium difficile Isolates from Single, Relapse, and Reinfection Cases

Abstract

In this study, we investigated the correlation between the microbiological characteristics of Clostridium difficile clinical isolates and the recurrence of C. difficile-associated disease (CDAD). Twenty C. difficile isolates recovered from 20 single infection cases and 53 isolates from 20 recurrent cases were analyzed by pulsed-field gel electrophoresis (PFGE) and PCR ribotyping, and the cytotoxicity, antimicrobial susceptibility, and sporulation/germination rates of the isolates were examined. Recurrent cases were divided into relapse or reinfection cases by the results of C. difficile DNA typing. Among the 20 recurrent cases, 16 cases (80%) were identified to be relapse cases caused by the initial strain and the remaining 4 cases (20%) were identified to be reinfection cases caused by different strains. All 73 isolates were susceptible to both vancomycin and metronidazole, but resistance against clindamycin, ceftriaxone, erythromycin, and ciprofloxacin was found in 87.7%, 93.2%, 87.7%, and 100% of the isolates, respectively. No correlations between DNA typing group, cytotoxicity, and sporulation rate of isolates and infection status, i.e., single, relapse, or reinfection, were observed. However, the isolates recovered from relapse cases showed a significantly higher germination rate when incubated in medium lacking the germination stimulant sodium taurocholate. These results indicate that the germination ability of C. difficile may be a potential risk factor for the recurrence of CDAD.

Factors Affecting Treatment and Recurrence of <i>Clostridium difficile</i> Infections

“…22) Another previous study also showed that all 73 isolates were susceptible to both metronidazole and vancomycin. 23) Thus, C. difficile isolates in Japan appear to be susceptible to both agents. In the present study, no significant difference was observed in the cure rate between vancomycin and metronidazole (Tables 2, 3).…”

“…26) Among the 20 recurrent cases examined, 16 cases (80%) were identified as cases of recurrence caused by the initial strain while the remaining 4 cases (20%) were identified as reinfection cases by different strains; therefore, Oka et al suggested that the germination ability of C. difficile may be a potential risk factor for the recurrence of CDI. 23) Cancer chemotherapy is a risk factor for CDI that is mediated by the antimicrobial activity of several chemotherapeutic agents 10,27) and could also be related to the immunosuppressive effects of neutropenia. 28,29) The risk of recurrent disease has been shown to be related to the host immune response.…”

Diagnosis of Clostridium difficile Infection: an Ongoing Conundrum for Clinicians and for Clinical Laboratories

“…The most commonly pre-scribed antimicrobial therapy for C. difficile infection is metronidazole or oral vancomycin. As the concentrations of these drugs in the feces are typically high, treatment failures are rarely thought to be due to resistance of the organisms to the antimicrobial therapy (34,170). However, metronidazole concentrations in the stool can be variable depending on the consistency of the stool and the amount of inflammation in the gut.…”

Esporas de Clostridium difficile y su relevancia en la persistencia y transmisión de la infección

“…Las esporas de C. difficile que no fueron eliminadas en las deposiciones pueden persistir en el tracto colónico del paciente, lo que pudiese favorecer los episodios de recurrencia de IACD. Los eventos de recurrencia de IACD se pueden clasificar como: recaída, si es causada por la misma cepa responsable del primer episodio, lo que representan ~75% de las recurrencias; re-infección, si es causada por una cepa diferente a la del episodio inicial, con una frecuencia de ~25% de todos las recurrencias 3 . En ambos casos, la recurrencia de IACD se vería favorecida por una modificación extrema de la microbiota colónica y la consecuente alteración de los mecanismos de defensa intrínsecos de esta microbiota contra de las infecciones por bacterias patógenas 29,30 .…”

“…El cuadro clínico de las IACD puede ir desde una diarrea leve y auto limitada hasta una colitis fulminante con pseudomembranas y megacolon tóxico 2 . La tasa de mortalidad de las IACD es aproximadamente de 5%; sin embargo, uno de los mayores problemas de las IACD es su elevada tasa de recurrencia, la que puede alcanzar tasas de 20% después de un primer episodio 3 . Clostridium difficile secreta dos principales factores de virulencia, la enterotoxina TcdA y la citotoxina TcdB 4 .…”