Using whole genome sequencing of isolates from a cohort of patients with Clostridium difficile infection (CDI) and colonization, we found that incident CDI cases were more likely to be linked to an ...infected than colonized donor.
Abstract
Background
Whole genome sequencing (WGS) studies can enhance our understanding of the role of patients with asymptomatic Clostridium difficile colonization in transmission.
Methods
Isolates obtained from patients with Clostridium difficile infection (CDI) and colonization identified in a study conducted during 2006-2007 at 6 Canadian hospitals underwent typing by pulsed-field gel electrophoresis, multilocus sequence typing, and WGS. Isolates from incident CDI cases not in the initial study were also sequenced where possible. Ward movement and typing data were combined to identify plausible donors for each CDI case, as defined by shared time and space within predefined limits. Proportions of plausible donors for CDI cases that were colonized, infected, or both were examined.
Results
Five hundred fifty-four isolates were sequenced successfully, 353 from colonized patients and 201 from CDI cases. The NAP1/027/ST1 strain was the most common strain, found in 124 (62%) of infected and 92 (26%) of colonized patients. A donor with a plausible ward link was found for 81 CDI cases (40%) using WGS with a threshold of ≤2 single nucleotide polymorphisms to determine relatedness. Sixty-five (32%) CDI cases could be linked to both infected and colonized donors. Exclusive linkages to infected and colonized donors were found for 28 (14%) and 12 (6%) CDI cases, respectively.
Conclusions
Colonized patients contribute to transmission, but CDI cases are more likely linked to other infected patients than colonized patients in this cohort with high rates of the NAP1/027/ST1 strain, highlighting the importance of local prevalence of virulent strains in determining transmission dynamics.
Background. An increase in the incidence and severity of Clostridium difficile-associated disease in Québec and the United States has been associated with a hypervirulent strain referred to as North ...American pulsed-field type 1 (NAP1)/027. Methods. In 2005, a prospective study was conducted in 88 Québec hospitals, and 478 consecutive nosocomial isolates of C. difficile were obtained. The isolates were subjected to pulsed-field gel electrophoresis (PFGE) typing, antimicrobial susceptibility testing, and detection of binary toxin genes and tcdC gene deletion. Data on patient age and occurrence of complications were collected. Results. PFGE typing of 478 isolates of C. difficile yielded 61 PFGE profiles. Pulsovars A (57%), B (10%), and B1 (8%) were predominant. The PFGE profile of pulsovar A was identical to that of strain NAP1. It showed 67% relatedness with 15 other PFGE patterns, among which 11 had both binary toxin genes and a partial tcdC deletion but different antibiotic susceptibility profiles. Pulsovars B and B1 were identical to strain NAP2/ribotype 001. In hospitals showing a predominant clonal A or B-B1 PFGE pattern, incidence of C. difficile-associated disease was 2 and 1.3 times higher, respectively, than in hospitals without any predominant clonal PFGE pattern. Severe disease was twice as frequent among patients with strains possessing binary toxin genes and tcdC deletion than among patients with strains lacking these virulence factors. Conclusions. This study helped to quantify the impact of strain NAP1 on the incidence and severity of C. difficile-associated disease in Québec in 2005. The identification of the geographic dissemination of this predominant strain may help to focus regional infection-control efforts.
Background Clostridium difficile (CD) is the leading cause of health care–associated diarrhea and can result in asymptomatic carriage. Rates of asymptomatic CD colonization on hospital admission ...range from 1.4%-21%. The objective of this study was to evaluate host and bacterial factors associated with colonization on admission. Methods The Consortium de recherche québécois sur le Clostridium difficile study provided data for analysis, including demographic information, known risk factors, and potential confounding factors, prospectively collected for 5,232 patients from 6 hospitals in Quebec and Ontario over 15 months from 2006-2007. Stool or rectal swabs were obtained for culture on admission. Pulsed-field gel electrophoresis was performed on the isolates. The presence of antibody against CD toxins A and B was measured. Results There were 212 (4.05%) patients colonized with CD on admission, and 5,020 patients were not colonized with CD. Multivariate logistic regression analysis showed that hospitalization within the last 12 months, use of corticosteroids, prior CD infection, and presence of antibody against toxin B were associated with colonization on admission. Of patients colonized on admission, 79.4% had non-NAP1, non-NAP2 strains. Conclusion There are identifiable risk factors among asymptomatic CD carriers that could serve in their detection and provide a basis for targeted screening.
In this prospective cohort study of patients admitted to hospitals in Quebec and Ontario, 2.8% of patients had
Clostridium difficile
infection and 3.0% had asymptomatic
C. difficile
colonization ...during hospitalization. Most patients with
C. difficile
infection had the NAP1 strain.
Clostridium difficile
is the leading cause of health care–associated infectious diarrhea.
1
After exposure to
C. difficile,
some patients remain asymptomatic, whereas others have illness ranging from mild diarrhea to fulminant colitis.
2
Outbreaks of
C. difficile
infection in North America and Europe have been attributed to the emergence of an epidemic strain (North American pulsed-field gel electrophoresis PFGE type 1 NAP1).
3
,
4
Risk factors for
C. difficile
infection include antibiotic use, advanced age, increased severity of underlying illness, prior hospitalization, use of feeding tubes, gastrointestinal surgery, and use of proton-pump inhibitors.
5
,
6
Variability in host factors may explain the wide spectrum . . .
In the first half of 2003, the number of
C. difficile
infections (22.5 per 1000 admissions) increased in Quebec, Canada. This outbreak was associated with fluoroquinolone and cephalosporin use as ...well as an increase in
C. difficile
–associated mortality (to 6.9 percent) and colectomy (to 1.9 percent). The outbreak strain was found to have enhanced virulence, as suggested by the presence of binary toxin genes and the partial deletion of a toxin-repressor gene.
In the first half of 2003, the number of
C. difficile
infections (22.5 per 1000 admissions) increased in Quebec, Canada. This outbreak was associated with fluoroquinolone and cephalosporin use as well as an increase in
C. difficile
–associated mortality and colectomy.
Clostridium difficile
is the leading cause of nosocomial infectious diarrhea.
1
The most important risk factor for
C. difficile
–associated diarrhea is prior antibiotic use.
2
Some patients remain asymptomatic after exposure to
C. difficile,
whereas illness ranging from mild diarrhea to fulminant colitis develops in others.
2
Only 1 to 5 percent of affected patients have severe disease, leading to colectomy, intensive care, or death.
3
,
4
The best-described
C. difficile
virulence factors are toxins A and B, encoded by the genes
tcdA
and
tcdB,
respectively.
5
Together with two regulatory genes (
tcdC
and
tcdD
) and a porin gene (
tcdE
), . . .
Abstract
Mycobacterium africanum is an important cause of human tuberculosis and is found almost exclusively in West Africa. We identified a cluster of patients in Montreal, Canada, with M africanum ...disease that share identical genotypic signatures by mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing and a putative epidemiological link, thus providing evidence of possible local transmission of M africanum in Montreal over a 10-year period.
Highlight
Musculoskeletal cystic echinococcosis can present as an isolated disease mimicking neoplasia. Along with albendazole therapy, complete excision avoiding cyst rupture is essential to prevent ...disease dissemination and hypersensitivity reactions. Conventional epidemiology and molecular typing can help differentiate between domestic and sylvatic strains of echinococcosis in the traveler and migrant population.
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