Epidemiology and Molecular Characterization of Clostridium difficile Strains from Patients with Diarrhea: Low Disease Incidence and Evidence of Limited Cross-Infection in a Swedish Teaching Hospital

Abstract

We prospectively studied the epidemiology of Clostridium difficile-associated diarrhea (CDAD) in a 900-bed hospital over the course of 12 months by PCR-ribotyping of C. difficile isolates. A total of 304 cases were diagnosed, corresponding to an overall incidence of 7/1,000 admissions, with higher rates in nephrology, hematology, and organ transplantation wards (37, 30, and 21/1,000), and 72% were classified as hospital associated (onset in hospital or onset at home but after a hospital stay within 2 months). All 382 isolates from 227 of 304 (75%) patients available for PCR-ribotyping were typeable, yielding 70 PCR-ribotypes. The three most common types comprised 30% of hospital-associated and 34% of community-associated cases, indicating import via admitted patients as a major source of C. difficile strains occurring in the hospital. Of the 227 patients studied, 38% each contributed 2 to 13 fecal samples positive for C. difficile over the course of the study period. Repeat isolates of the same PCR-ribotype as the first isolate were found in 79% of these patients and in 95% of specimens delivered within 30 days, compared to 63% of those obtained at 31 to 204 days. Nosocomial acquisition of CDAD, defined as the proportion of cases sharing C. difficile type and admitted to the same ward within 2 or 12 months, was 20% and 32% of hospital-associated cases and 14% and 23% of all cases, respectively. Thus, most CDAD cases diagnosed over the course of the study period, including those associated with hospitalization, appeared to be caused by endogenous C. difficile strains rather than by strains truly being acquired in the hospital.

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

“…8) Furthermore, immunosuppression has been identified as an independent risk factor for the development of CDI. [9][10][11][12][13] The antimicrobial agents vancomycin and metronidazole have been used to treat CDI. Clinical practice guidelines recommend that the dosages of metronidazole and vancomycin are 500 mg orally 3 times per day and 125 mg orally 4 times per day for 10-14 d, respectively.…”

Geographical clustering of cases of infection with moxifloxacin-resistant Clostridium difficile PCR-ribotypes 012, 017 and 046 in Sweden, 2008 and 2009

“…Exceptions were type SE37, for example, which was confirmed in the ECDIS study as one of six novel types (PCR ribotype 231) [19]. Another unknown type was SE21, which closely resembled types SE21a and SE21b as well as reference strains of PCR-ribotypes 014 and 020 [4]. Type SE21 was verified as a member of the 014/020 group: in total this group comprised 19% of all C. difficile isolates in our study in Sweden in 2009.…”

“…Type 012 is related to serogroup C [29] and has been reported as a common type in Sweden, Greece and Hungary [2,19] while toxin A-negative, toxin B-positive type 017 has been found to be associated with outbreaks in, for example, Poland, Canada and the Netherlands [6,30]. Regarding type 231/SE37, the proportion of this type was 0.8 % at the Karolinska University Hospital, Huddinge, Sweden, in 1999 [4], but there is no information on whether this type has caused any outbreaks in other countries.…”

“…[23]). From previous geographically localised studies in Sweden in 1999 to 2001, the six most common types were 014/SE21, 012, 001, 020, 002 and 005 [2][3][4]. All these were still among the most common types in 2009.…”

“…C. difficile is typically isolated from faeces of 1-5% of healthy individuals, but colonisation increases upon admission to hospitals. Hospital-based studies performed in 1999 to 2001 showed that nosocomial spread of C. difficile was rare in Swedish hospitals in which infection control routines were implemented, although there were small outbreaks associated with multiresistant PCR-ribotype 012/SE17 [2][3][4]. Many outbreaks involving other C. difficile types have been reported in Europe and the rest of the world [5][6][7][8], particularly those caused by moxifloxacin-resistant PCR-ribotype 027/PFGE NAP1 [9][10][11][12][13][14][15][16][17] …”