Treatment of Clostridium difficile-associated diarrhea and colitis

Proteomic Signatures of Clostridium difficile Stressed with Metronidazole, Vancomycin, or Fidaxomicin

The anaerobic pathogen Clostridium difficile is of growing significance for the health care system due to its increasing incidence and mortality. As C. difficile infection is both supported and treated by antibiotics, a deeper knowledge on how antimicrobial agents affect the physiology of this important pathogen may help to understand and prevent the development and spreading of antibiotic resistant strains. As the proteomic response of a cell to stress aims at counteracting the harmful effects of this stress, it can be expected that the pattern of a pathogen’s responses to antibiotic treatment will be dependent on the antibiotic mechanism of action. Hence, every antibiotic treatment is expected to result in a specific proteomic signature characterizing its mode of action. In the study presented here, the proteomic response of C. difficile 630∆erm to vancomycin, metronidazole, and fidaxomicin stress was investigated on the level of protein abundance and protein synthesis based on 2D PAGE. The quantification of 425 proteins of C. difficile allowed the deduction of proteomic signatures specific for each drug treatment. Indeed, these proteomic signatures indicate very specific cellular responses to each antibiotic with only little overlap of the responses. Whereas signature proteins for vancomycin stress fulfil various cellular functions, the proteomic signature of metronidazole stress is characterized by alterations of proteins involved in protein biosynthesis and protein degradation as well as in DNA replication, recombination, and repair. In contrast, proteins differentially expressed after fidaxomicin treatment can be assigned to amino acid biosynthesis, transcription, cell motility, and the cell envelope functions. Notably, the data provided by this study hint also at so far unknown antibiotic detoxification mechanisms.

A Review of Management of Clostridium difficile Infection: Primary and Recurrence

Clostridium difficile infection (CDI) is a potentially fatal illness, especially in the elderly and hospitalized individuals. The recurrence and rates of CDI are increasing. In addition, some cases of CDI are refractory to the currently available antibiotics. The search for improved modalities for the management of primary and recurrent CDI is underway. This review discusses the current antibiotics, fecal microbiota transplantation (FMT) and other options such as immunotherapy and administration of non-toxigenic Clostridium difficile (CD) for the management of both primary and recurrent CDI.

Long-Term Clinical Outcome of Clostridium difficile Infection in Hospitalized Patients: A Single Center Study

Background/Aims

Antibiotic usage and increasingly aging populations have led to increased incidence of Clostridium difficile infection (CDI) in worldwide. Recent studies in Korea have also reported increasing CDI incidence; however, there have been no reports on the long-term outcomes of CDI. We therefore investigated the long-term clinical outcomes of patients with CDI, including delayed recurrence, associated risk factors and mortality.

Methods

Hospitalized patients diagnosed with CDI at Seoul Paik Hospital between January 2007 and December 2008 were included. Their medical records were retrospectively investigated. 'Delayed recurrence' was defined as a relapse 8 weeks after a successful initial treatment. Multivariate logistic regression analysis was performed to identify risk factors for the delayed recurrence. Kaplan-Meier curves were used to analyze mortality rates.

Results

A total of 120 patients were enrolled; among them, 87 were followed-up for at least 1 year, with a mean follow-up period of 34.1±25.1 months. Delayed recurrence was observed in 17 patients (19.5%), and significant risk factors were age (over 70 years, P=0.049), nasogastric tube insertion (P=0.008), and proton pump inhibitor or H₂-blocker treatments (P=0.028). The 12- and 24-month mortality rates were 24.6% and 32.5%, respectively. No deaths were directly attributed to CDI.

Conclusions

Delayed recurrence of CDI was not rare, occurring in 19.5% of the study population. Although CDI-related mortality was not reported, 2-year (32.5%) mortality rate of CDI patients implies that a CDI diagnosis may predict severe morbidity and poor prognosis of the underlying disease.

Pharmacodynamic studies of vancomycin, metronidazole and fusidic acid against Clostridium difficile

BACKGROUND

Pharmacodynamic studies of antibiotics have attracted great interest in recent years. However, studies on the pharmacodynamics of different antibiotics against Clostridium difficile are scarce.

METHODS

The postantibiotic effects (PAE) and the postantibiotic sub-minimum inhibitory concentration (MIC) effects (PA SME) of vancomycin, metronidazole and fusidic acid were investigated by viable counts against three different strains of C. difficile. The killing rate and extent of the three antibiotics against the same strains were also studied by adding 2, 4, 8, 16 and 32x MIC of the three antibiotics, respectively.

RESULTS

Metronidazole exerted a very rapid bactericidal effect at concentrations of 8x MIC and above against all three strains investigated. Vancomycin gave overall less kill in comparison to metronidazole and was bacteriostatic against two of the three strains. Fusidic acid exerted a concentration-dependent killing against two of the strains. Vancomycin exerted short PAEs and PA SMEs against all three strains. Significantly longer PAEs and PA SMEs were noted for fusidic acid. Metronidazole gave similar short PAEs like vancomycin but longer PA SMEs were noted against two of the investigated strains.

CONCLUSION

Metronidazole exerted the most prominent bactericidal effect greater than fusidic acid and greater than vancomycin. Fusidic acid gave overall the longest PAEs and PA SMEs greater than metronidazole and greater than vancomycin.

Reassessment of Clostridium difficile susceptibility to metronidazole and vancomycin

Clostridium difficile is the most frequently identified enteric pathogen in patients with nosocomially acquired, antibiotic-associated diarrhea. The drugs most commonly used to treat diseases associated with C. difficile are metronidazole and vancomycin. Most clinical laboratories assume that all C. difficile isolates are susceptible to metronidazole and vancomycin. We report on the antimicrobial susceptibilities of 415 C. difficile isolates to metronidazole and vancomycin over an 8-year period (1993 to 2000). The overall rate of resistance to metronidazole at the critical breakpoint (16 microg/ml) was 6.3%. Although full resistance to vancomycin was not observed, the overall rate of intermediate resistance was 3.1%. One isolate had a combination of resistance to metronidazole and intermediate resistance to vancomycin. Rates of resistance to metronidazole and vancomycin were higher among isolates from human immunodeficiency virus-infected patients. Molecular typing methods proved the absence of clonality among the isolates with decreased susceptibilities to the antimicrobials tested.