Nosocomial Diarrhea Research Articles

Ultrastructural Variability of the Exosporium Layer of Clostridium difficile Spores.

The anaerobic sporeformer Clostridium difficile is the leading cause of nosocomial antibiotic-associated diarrhea in developed and developing countries. The metabolically dormant spore form is considered the transmission, infectious, and persistent morphotype, and the outermost exosporium layer is likely to play a major role in spore-host interactions during the first contact of C. difficile spores with the host and for spore persistence during recurrent episodes of infection. Although some studies on the biology of the exosporium have been conducted (J. Barra-Carrasco et al., J Bacteriol 195:3863-3875, 2013, http://dx.doi.org/10.1128/JB.00369-13; J. Phetcharaburanin et al., Mol Microbiol 92:1025-1038, 2014, http://dx.doi.org/10.1111/mmi.12611), there is a lack of information on the ultrastructural variability and stability of this layer. In this work, using transmission electron micrographs, we analyzed the variability of the spore's outermost layers in various strains and found distinctive variability in the ultrastructural morphotype of the exosporium within and between strains. Through transmission electron micrographs, we observed that although this layer was stable during spore purification, it was partially lost after 6 months of storage at room temperature. These observations were confirmed by indirect immunofluorescence microscopy, where a significant decrease in the levels of two exosporium markers, the N-terminal domain of BclA1 and CdeC, was observed. It is also noteworthy that the presence of the exosporium marker CdeC on spores obtained from C. difficile biofilms depended on the biofilm culture conditions and the strain used. Collectively, these results provide information on the heterogeneity and stability of the exosporium surface of C. difficile spores. These findings have direct implications and should be considered in the development of novel methods to diagnose and/or remove C. difficile spores by using exosporium proteins as targets.

Effectiveness of Lactobacillus reuteri DSM 17938 for the Prevention of Nosocomial Diarrhea in Children: A Randomized, Double-blind, Placebo-controlled Trial.

Multiple studies of probiotics used to prevent nosocomial diarrhea have provided conflicting results. The effects likely depend on the probiotic strain and/or dosage. The aim of this study was to assess the effectiveness of Lactobacillus reuteri DSM 17938 (L. reuteri; daily dose of 1 × 10 colony forming units) for preventing nosocomial diarrhea in children. We conducted a multicenter, randomized, double-blind, placebo-controlled trial in 184 children, 1-48 months of age, admitted to the hospital for reasons other than diarrhea. A computer-generated randomization scheme was used to allocate participants to receive either L. reuteri (n = 91) at a daily dose of 1 × 10 colony forming units, for the duration of hospitalization, or an identical appearing placebo (n = 93). Patients, study personnel and data analysts were blinded to assignment. The primary outcome was the occurrence of nosocomial diarrhea (≥3 loose or watery stools in 24 hours that occurred >72 hours after admission). Analysis was by intention-to-treat. Baseline characteristics were similar in the 2 groups. Nosocomial diarrhea occurred in 13 (7.1%) children. No difference was found between the L. reuteri and the placebo groups (7/91 vs 6/93, respectively; relative risk: 1.19; 95% confidence interval: 0.43-3.27). There was also no difference between the L. reuteri and placebo groups for any of the secondary outcomes, including adverse effects. Rotavirus vaccination status had no effect on the results. L. reuteri in the dosage regimen used was not effective in preventing nosocomial diarrhea in children.

Nisin is an effective inhibitor of Clostridium difficile vegetative cells and spore germination.

Clostridium difficile is the most frequently identified enteric pathogen in patients with nosocomial antibiotic-associated diarrhoea and pseudomembranous colitis. Several clinically isolated C. difficile strains are resistant to antibiotics other than metronidazole and vancomycin. Recently, bacteriocins of lactic acid bacteria have been proposed as an alternative or complementary treatment. The aim of this study was to investigate the inhibitory effect of nisin, a bacteriocin produced by several strains of Lactococcus lactis, against clinical isolates of C. difficile. Nisin Z obtained from culture of L. lactis subsp. lactis biovar. diacetylactis was tested along with commercial nisin A. The effect of nisin A on C. difficile spores was also examined. Nisin A and Z both inhibited the growth of all C. difficile isolates, and MICs were estimated at 6.2 μg ml(-1) for nisin Z and 0.8 μg ml(-1) for nisin A. In addition, C. difficile spores were also susceptible to nisin A (25.6 μg ml(-1)), which reduced spore viability by 40-50%. These results suggested that nisin and hence nisin-producing Lactococcus strains could be used to treat C. difficile-associated diarrhoea.

Nosocomial Clostridium difficile-associated diarrhoea in Assiut University Children’s Hospital, Egypt

Background: There are no large epidemiological studies of Clostridium difficile-associated disease (CDAD) in hospitalised children.Aim: To describe the frequency, demography, clinical features and outcome of nosocomial CDAD in children admitted to Assiut University Children’s Hospital, Egypt.Patients and Methods: In this descriptive cross-sectional study, 72 children developed nosocomial diarrhoea between April 2010 and March 2011. A medical history, clinical assessment and culture for Clostridium difficile and direct toxin detection from stool samples by enzyme immuno-assay were undertaken in all patients.Results: CDAD was diagnosed in 17 (23·6%) patients. Those aged ≤12 months were the most commonly affected (eight, 47%). The main cause of admission was respiratory disorders (eight, 47% of cases), followed by surgical problems (three, 17·7%). Ten patients (58·8%) had severe symptoms. There were no statistically significant differences between any of the demographic or laboratory data for children with CDAD and children with other causes of nosocomial diarrhoea. None of the patients developed complications. Seven children with CDAD (41·2%) had recurrence.Conclusion: CDAD is an important cause of nosocomial diarrhoea in children in Assiut University Children’s Hospital. Established guidelines should be followed in all hospitals to minimise exposure to the pathogen. Physicians can do much to reduce the risk of a severe outcome in children by early identification and rapid management. Further research should be undertaken to identify the risk factors for recurrence.

Factors Determining Physicians’ Decision Making In Treatment and the Outcomes of Nosocomial Diarrhea in a Tertiary Care Hospital: A Prospective Cohort

Abstract Background: Patients with nosocomial diarrhea (ND) are empirically treated as if they have Clostridium-difficileassociated diarrhea (CDAD), even if their stool tests are negative for C. difficile. We determined the incidence, risk factors, and treatment outcomes of patients with ND in Siriraj Hospital. Methods: All patients with ND were enrolled. Demographic data, clinical and laboratory and stool for C. difficile toxin were collected including severity and outcomes of ND. Descriptive analysis was performed using mean ± SD/ median ± IQR for continuous data and frequency for categorical data. χ2/Fisher’s exact tests were used to compare groups. Predictors that might determine the decision to prescribe empirical treatment were identified using regression analysis. Results: We enrolled 105 patients (mean age 67 years), and 89.5% were non-CDAD. During ND development, 95.7% received antibiotics and 3.2% chemotherapy. Eleven patients had CDAD. Common findings included: fever 42.6%, abdominal pain and hemodynamic instability 7.4%; 11.7% had blood cells in their stools and 85.1% had low serum albumin. Median white blood cell count and serum creatinine were 11-880 cells/mm3 and 1.4 mg/dl, respectively. CDAD treatment was prescribed in 48.9% regardless of the toxin result; 95.7% received metronidazole and 4.3% vancomycin. Response outcomes did not differ significantly between the two groups. Conclusion: Incidence of ND was 4.7%, and 10.6% of these had CDAD. 43.8% of patients with ND were treated as CDAD although they were negative for C. difficile toxin. There were no significant differences in clinical and laboratory features and outcomes between treated and untreated groups. Further study is needed to determine if empirical treatment of CDAD is justified in all cases of ND.

Prevalence of Nosocominal Toxigenic Clostridium difficile in Children Under 5 Years in Hajar Hospital, Shahrekord, Iran.

Diarrheal disease is still a main cause of morbidity and mortality in children across the world [1]. Nosocomial diarrhea is a common complication in inpatients [2]. Clostridium difficile is the most common cause of nosocomial diarrheal and antibiotics-associated diarrheal diseases [3–5]. Hospitalization period of patients was from three to 18 days with the mean 5.5±2.21 days. Duration of antibiotic consumption was three to 18 days with the mean 5.4±2.1 days. Diarrhea duration was from one to three days with mean 1.67±0.56 days. The frequency of diseases leading to hospitalization is summarized in [Table/Fig-1]. [Table/Fig-1]: Causes of hospitalization. The types of antibiotic which were administered to children are summarized in [Table/Fig-2]. [Table/Fig-2]: Types of antibiotic consumption. Two patients of positive cases were boy and four were girl. Five positive cases were observed among other antibiotic treatments. Positive results were not related to sex and age of the patients, duration of hospitalization, antibiotic consumption and diarrhea (p>0.05). In this study the prevalence of nosocomial diarrhea due to C. difficile was 6 (3%). Statistical tests indicated no significant difference in the ELISA positivity prevalence in stool samples of the patients with nosocomial regarding for the duration of hospitalization in day. This could be due to the low number of ELISA-positive stool samples of patients with nosocomial diarrhea. It is concluded that C. difficile is an important reason for nosocomial diarrhea and the most important prescribed antibiotic is cefotoxim. Determining the prevalence of C. difficile and the types of strategies that can deal with this pathogen is important. It is recommended in future studies polymerase chain reaction be used to test and determine the strains of bacteria because this test is more accurate.

Predominance and high antibiotic resistance of the emerging Clostridium difficile genotypes NAPCR1 and NAP9 in a Costa Rican hospital over a 2-year period without outbreaks

Clostridium difficile is the major causative agent of nosocomial antibiotic-associated diarrhea. In a 2009 outbreak of C. difficile-associated diarrhea that was recorded in a major Costa Rican hospital, the hypervirulent NAP1 strain (45%) predominated together with a local genotype variant (NAPCR1, 31%). Both strains were fluoroquinolone-resistant and the NAPCR1 genotype, in addition, was resistant to clindamycin and rifampicin. We now report on the genotypes and antibiotic susceptibilities of 68 C. difficile isolates from a major Costa Rican hospital over a 2-year period without outbreaks. In contrast to our previous findings, no NAP1 strains were detected, and for the first time in a Costa Rican hospital, a significant fraction of the isolates were NAP9 strains (n=14, 21%). The local NAPCR1 genotype remained prevalent (n=18, 26%) and coexisted with 14 strains (21%) of classic hospital NAP types (NAP2, NAP4, and NAP6), eight new genotypes (12%), four environmental strains classified as NAP10 or NAP11 (6%), three strains without NAP designation (4%) and seven non-toxigenic strains (10%). All 68 strains were resistant to ciprofloxacin, 88% were resistant to clindamycin and 50% were resistant to moxifloxacin and rifampicin. Metronidazole and vancomycin susceptibilities were universal. The NAPCR1 and NAP9 strains, which have been associated with more severe clinical infections, were more resistant to antibiotics than the other strains. Altogether, our results confirm that the epidemiology of C. difficile infection is dynamic and that A−B+ strains from the NAP9 type are on the rise not only in the developed world. Moreover, our results reveal that the local NAPCR1 strains still circulate in the country without causing outbreaks but with equally high antibiotic-resistance rates and levels.

Overview of Clostridium difficile Infection in Cancer Patients

Clostridium difficile Associated Diarrhoea (CDAD) is the leading cause of nosocomial diarrhoea. Clostridium difficile Infections (CDIs) may be induced by medication or medical procedures that disrupt normal bowel flora or interfere with bowel motility. The emergence of hyper-virulent strains of CDI, reports of severe or recurrent CDI in immunocompetent populations, advent of various infection control challenges, and diagnostic and therapeutic dilemmas have contributed to a shift in the disease paradigm. However, there is insufficient data on the risk of CDI in vulnerable cancer patients receiving chemotherapy or who are admitted to health care settings for long periods of time. This review describes the epidemiology, risk factors, pathophysiology, and management of CDIs in cancer patients receiving chemotherapeutic agents.

Immunogenicity and protective efficacy of recombinant Clostridium difficile flagellar protein FliC

Clostridium difficile is a Gram-positive bacillus and is the leading cause of toxin-mediated nosocomial diarrhea following antibiotic use. C. difficile flagella play a role in colonization, adherence, biofilm formation, and toxin production, which might contribute to the overall virulence of certain strains. Human and animal studies indicate that anti-flagella immune responses may play a role in protection against colonization by C. difficile and subsequent disease outcome. Here we report that recombinant C. difficile flagellin (FliC) is immunogenic and protective in a murine model of C. difficile infection (CDI) against a clinical C. difficile strain, UK1. Passive protection experiments using anti-FliC polyclonal serum in mice suggest this protection to be antibody-mediated. FliC immunization also was able to afford partial protection against CDI and death in hamsters following challenge with C. difficile 630Δerm. Additionally, immunization against FliC does not have an adverse effect on the normal gut flora of vaccinated hamsters as evidenced by comparing the fecal microbiome of vaccinated and control hamsters. Therefore, the use of FliC as a vaccine candidate against CDI warrants further testing.

Association between NSAIDs and Clostridium difficile-Associated Diarrhea: A Systematic Review and Meta-Analysis.

Objective. Clostridium difficile infection is a leading cause of nosocomial diarrhea in developed countries. Studies evaluating the associations of increased risk of community-acquired CDAD and the use of nonsteroidal anti-inflammatory drugs (NSAIDs) have yielded inconclusive results. We conducted a systematic review and meta-analysis to compare the odds of NSAID exposure in patients with CDAD versus patients without CDAD in both community-based and healthcare-associated settings. Methods. Relevant observational studies indexed in PubMed/MEDLINE and EMBASE up to February 2015 were analyzed and data were extracted from nine studies. Of these, eight studies were included in the meta-analysis. Results. A search of the databases resulted in 987 articles. The nine studies from which data were extracted involved over 39,000 subjects. The pooled odds ratio for history of NSAID use in participants with CDAD compared with controls was 1.41 (95% CI 1.06–1.87; p < 0.01), indicating a significant increased odds of CDAD among patients exposed to NSAIDs. Conclusions. To the best of our knowledge, this is the first study of its nature to demonstrate the association between the use of NSAIDs and increased risk of CDAD. Further studies to evaluate if any specific types of NSAIDs can increase the risk of CDAD are warranted.

Factors Favouring the Development of Clostridium Difficile Infection in Critically Ill Patients.

Assessment of favouring factors of Clostridium difficile infections as well as the interactions between them, in critically ill hospitalized patients undergoing complex medical and surgical treatments. A retrospective case-control study involving eighty patients admitted in the Intensive Care Unit (ICU) of the County Clinical Emergency Hospital Tîrgu-Mureş was conducted between January and October 2014. Patients aged eighteen years and over, who had undergone complex medical and surgical treatment, were divided into two subgroups. Group 1 included patients who developed diarrhoea but were not diagnosed as having a Clostridium difficile infection (CDI). Group 2 included patients who developed diarrhoea due to CDI as indicated by a positive culture and the expression of exotoxin. The assessed parameters were age, length of stay (LOS), antibiotic spectrum, association with proton pump inhibitors (PPI) or H2-receptor antagonists, immunological status, the presence or lack of gastrointestinal tract surgery. The mean age was 64.6 years with an average LOS of 10 days. Fifty-six percent of patients came to the ICU from internal medicine wards and forty-three percent from surgical wards. 20.5% of them were immunosuppressed. Co-association of ceftriaxone and pantoprazole significantly increased the risk of CDI compared to co-administration of any other antibiotic or pantoprazole (p=0.01). The odds ratio for Pantoprazole together with any antibiotic versus antibiotic therapy alone was significantly higher (p=0.018) with a sevenfold increase in the risk of positive exotoxin increase. Antibiotic use is associated with "no risk to develop CDI" in the first five days of administration. PPIs associated therapy increased the risk of CDI in first seventy-two hours regardless of the antibiotic type, and contributes to an active expression of CD exotoxin.

Treatment of Clostridium difficile infection in mice with vancomycin alone is as effective as treatment with vancomycin and metronidazole in combination

ObjectiveClostridium difficile is a major cause of nosocomial infectious diarrhoea. Treatment of C. difficile infection (CDI) depends on disease severity. A combination of vancomycin and metronidazole is often recommended in...

Systematic review with meta-analysis: long-term outcomes of faecal microbiota transplantation for Clostridium difficile infection.

Clostridium difficile infection is a major cause of nosocomial diarrhoea. To evaluate long-term (≥90 days) efficacy and safety of faecal microbiota transplantation for C. difficile infection and explore the factors affecting the faecal microbiota transplantation outcomes. MEDLINE, the Cochrane Library and EMBASE were searched and only observational studies that utilised faecal microbiota transplantation for C. difficile infection with long-term follow-up duration (≥90 days) were included. Primary cure rate, overall recurrence rate and early (<90 days) and late (≥90 days) recurrence rate were calculated. Eighteen observational studies with 611 patients were included. The primary cure rate was 91.2% (95% confidence interval, CI 86.7-94.8%). The overall recurrence rate was 5.5% (95% CI 2.2-10.3%). The early recurrence rate and late recurrence rate were 2.7% (95% CI 0.7-6.0%) and 1.7% (95% CI 0.4-4.2%) respectively. Most adverse events were expected, short-lived, self-limited and manageable. The association between faecal microbiota transplantation therapy and adverse events such as inflammatory bowel disease flare, infectious disease and autoimmune disease was a concern but remained insignificant. Old age (≥65 years) was identified as a risk factor for after faecal microbiota transplantation therapy. Upper gastrointestinal administration also results in less frequent primary cure. Faecal microbiota transplantation seems to be a highly effective and robust therapy for recurrent C. difficile infection. However, more quality studies, such as randomised controlled trials and cohort studies with control groups, are needed to confirm its long-term efficacy and safety.

Prevalence of Nosocomial Diarrhea Due to Adenoviruses 40 and 41 in a Paediatric Ward in Iran.

Enteric adenoviruses 40 (Ad40) and adenovirus 41 (Ad41) have been shown to be a significant cause of paediatric gastroenteritis worldwide, but no data are available for nosocomial diarrhea due to adenovirus in Iran. The present study was performed to determine the incidence of Ad40 and Ad41 in children less than five years with nosocomial diarrhea in Shahrekord, southwest Iran. Adenovirus was detected by polymerase chain reaction (PCR) in stool samples collected during one year (2010-2011) from children less than five years with nosocomial diarrhea admitted to a paediatric center in Shahrekord, Iran. Nosocomial diarrhea was defined as those occurring more than 72 hours after admission to hospital for non-diarrheal causes. PCR technique was used for investigation of Ad40 and Ad41. In total of 100 samples, Ad40 and Ad41 DNA was found to be positive in 14/100 (14%), and 8/100 (8%) of diarrheic patients less than five years, respectively. Ad40 and Ad41 are important causes of nosocomial diarrhea in less than five-year, hospitalized Iranian children.

Neutralization of Clostridium difficile Toxin B Mediated by Engineered Lactobacilli That Produce Single-Domain Antibodies.

Clostridium difficile is the primary cause of nosocomial antibiotic-associated diarrhea in the Western world. The major virulence factors of C. difficile are two exotoxins, toxin A (TcdA) and toxin B (TcdB), which cause extensive colonic inflammation and epithelial damage manifested by episodes of diarrhea. In this study, we explored the basis for an oral antitoxin strategy based on engineered Lactobacillus strains expressing TcdB-neutralizing antibody fragments in the gastrointestinal tract. Variable domain of heavy chain-only (VHH) antibodies were raised in llamas by immunization with the complete TcdB toxin. Four unique VHH fragments neutralizing TcdB in vitro were isolated. When these VHH fragments were expressed in either secreted or cell wall-anchored form in Lactobacillus paracasei BL23, they were able to neutralize the cytotoxic effect of the toxin in an in vitro cell-based assay. Prophylactic treatment with a combination of two strains of engineered L. paracasei BL23 expressing two neutralizing anti-TcdB VHH fragments (VHH-B2 and VHH-G3) delayed killing in a hamster protection model where the animals were challenged with spores of a TcdA(-) TcdB(+) strain of C. difficile (P < 0.05). Half of the hamsters in the treated group survived until the termination of the experiment at day 5 and showed either no damage or limited inflammation of the colonic mucosa despite having been colonized with C. difficile for up to 4 days. The protective effect in the hamster model suggests that the strategy could be explored as a supplement to existing therapies for patients.

Probiotics and Fecal Microbiota Transplant for Primary and Secondary Prevention of Clostridium difficile Infection.

Clostridium difficile infection (CDI) is the most common cause of nosocomial diarrhea and is associated with an increased risk of mortality. The use of probiotics and fecal microbiota transplantation (FMT) has been studied to reduce the incidence and severity of this infection, but variable efficacy and safety data have been reported. Probiotics are hypothesized to be effective in the management of CDI through a number of mechanisms that include maintenance of normal gastrointestinal flora, antimicrobial and antitoxin properties, and immunomodulatory effects. Despite promising results in small trials and meta-analyses, prospective, randomized, controlled trials have not demonstrated probiotics to be effective in the primary prevention of C. difficile-associated diarrhea (CDAD). Probiotics may be effective for secondary prevention in patients with recurrent CDI, but guidelines acknowledge the lack of compelling evidence. Trials are limited by the use of varying types of strains, numbers of strains, and doses of probiotics, as well the definitions of CDI and CDAD. FMT has been proposed as a method for restoring gut microbiota and has been shown to significantly increase the rate of cure in patients with recurrent CDI. Current studies have demonstrated minimal adverse effects, with no reports of transmission of infectious diseases; however, the optimal delivery method, sample preparation, and donor selection remain unclear. In this review, findings from recent literature are highlighted, and guideline recommendations for the use of these agents in the primary and secondary prevention of CDI are summarized.

Identification of a Novel Lipoprotein Regulator of Clostridium difficile Spore Germination.

Clostridium difficile is a Gram-positive spore-forming pathogen and a leading cause of nosocomial diarrhea. C. difficile infections are transmitted when ingested spores germinate in the gastrointestinal tract and transform into vegetative cells. Germination begins when the germinant receptor CspC detects bile salts in the gut. CspC is a subtilisin-like serine pseudoprotease that activates the related CspB serine protease through an unknown mechanism. Activated CspB cleaves the pro-SleC zymogen, which allows the activated SleC cortex hydrolase to degrade the protective cortex layer. While these regulators are essential for C. difficile spores to outgrow and form toxin-secreting vegetative cells, the mechanisms controlling their function have only been partially characterized. In this study, we identify the lipoprotein GerS as a novel regulator of C. difficile spore germination using targeted mutagenesis. A gerS mutant has a severe germination defect and fails to degrade cortex even though it processes SleC at wildtype levels. Using complementation analyses, we demonstrate that GerS secretion, but not lipidation, is necessary for GerS to activate SleC. Importantly, loss of GerS attenuates the virulence of C. difficile in a hamster model of infection. Since GerS appears to be conserved exclusively in related Peptostreptococcaeace family members, our results contribute to a growing body of work indicating that C. difficile has evolved distinct mechanisms for controlling the exit from dormancy relative to B. subtilis and other spore-forming organisms.

Diagnóstico microbiológico de la infección por Clostridium difficile

Clostridium difficile is the leading cause of nosocomial diarrhoea in developed countries, and is one of the main aetiologic agents of community diarrhea. The eruption of the hypervirulent strain BI/NAP1/027 has given rise to an increase in the morbidity and mortality of C.difficile infection (CDI). This document aims to review the main clinical pictures of CDI and the laboratory diagnosis, including sampling, transport and storage of specimens, specimen processing, diagnostic procedures, antimicrobial susceptibility testing, and molecular characterisation of the isolates. The main purpose of the article is to develop a practical document that provides answers to the main questions that arise in the laboratory diagnosis of CDI.

Molecular characterization of nosocomial Clostridium difficile infection in pediatric ward in Iran

Clostridium difficile is recognized as a major cause of nosocomial acquired antibiotic-associated diarrhea and pseudomembranous colitis. It is a significant financial burden on modern healthcare resources. This study aimed to assess the molecular characterization of C. difficile strains isolated from children under 5 years old suffered from nosocomial diarrhea. One hundred diarrheic and 130 non-diarrheic fecal samples were collected from pediatrics less than 5 years old. Samples were cultured and C. difficile isolates were subjected to the PCR technique to study the distribution of ribotypes of C. difficile using P3 and P5 primers. Fifty-two out of 100 samples (52 %) were positive for C. difficile. The prevalence of bacterium in healthy children was 4.61 %. Total prevalence of C. difficile in diarrheic girls and boys were 48.9 and 54.7 %, respectively. Thirteen to twenty-four month age children had the highest prevalence of C. difficile. The most commonly detected ribotypes in the C. difficile isolates of Iranian pediatrics were RT027 (11.52 %), R1 (9.61 %) and R13 (7.68 %). The ribotypes of all of the six bacterial isolates of healthy children was not diagnosed. According to the presence of C. difficile and R27 ribotype, a continued genotype surveillance of this bacterium is necessary to monitor changes in the prevalence of certain strains and to identify the emergence of new strains that could affect future vaccine strategies.

Clostridium difficile infection is a frequent but well-controlled event after hematopoietic cell transplantation

Clostridium difficile infection (CDI) is the most common cause of nosocomial diarrhea and represents a frequent and important source of gastrointestinal morbidity after hematopoietic stem cell transplantation (HSCT). Patients undergoing HSCT have several risk factors for the development of CDI, including multiple prior hospitalizations, frequent use of wide spectrum antibiotics, diseaseand treatment-related immunosuppression and mucosal barrier disruption secondary to conditioning regimens, particularly when they are myeloablative or include total body irradiation. Consequently, patients undergoing HSCT have an incidence of CDI that is higher than the general hospitalized population; it is as high as 15–30% after allogeneic HSCT.1 The majority of reports of CDI in HSCT patients originate from transplant centers located in developed countries. The manuscript by Pilcante et al.2 is the first report of the incidence, risk factors and outcomes of CDI in patients undergoing HSCT in an academic medical center in Chile. The results presented are compatible with other reports, confirming the global importance of CDI in HSCT patients. When compared to previous reports, the incidence of CDI observed in this study appears to be in the lower portion of the reported spectrum, possibly as a result of multiple factors, including antibiotic use patterns, cultural dietary habits, and possibly the degree of C. difficile colonization affecting the general hospitalized patient population of Chile. Recent reports by Kinnebrew3 and Bruminhent4 show high rates of colonization by C. difficile at the time of admission