Incidence and impact of Clostridium difficile infection in the UK, 1993-1996

The Use of Prophylactic Antibiotics before Primary Palatoplasty Is Not Associated with Lower Fistula Rates: An Outcome Study Using the Pediatric Health Information System Database

BACKGROUND

Previous attempts to study the effect of prophylactic antibiotics on the outcomes of cleft palate surgery have been hampered by the need for a very large sample size to provide adequate power to discern a potentially small therapeutic effect. This limitation can be overcome by querying large databases created by health care governing bodies.

METHODS

Data from the Pediatric Health Information System database were used for this analysis. Patients, aged 6 to 18 months, who had undergone primary palatoplasty (International Classification of Diseases, Ninth Revision, code 27.62) between 2004 and 2009 were included. Subsequent repair of an oronasal fistula between 2004 and 2015 was identified by International Classification of Diseases, Ninth Revision, procedure code 21.82. Pharmacy billing records were used to determine antibiotic administration. Associations between antibiotic administration and fistula repair were assessed using random-intercept logistic regression adjusting for age, sex, race, and cleft type.

RESULTS

Seven thousand one hundred sixty patients were available for analysis; of these, 460 (6.4 percent) had a subsequent repair of an oronasal fistula. Fistula rates were 5.9, 11.4, and 5.2 percent among patients given preoperative antibiotics, only postoperative antibiotics, and no antibiotics, respectively (p < 0.001). Multivariable analysis results showed that the odds of having an oronasal fistula among patients who were administered preoperative antibiotics did not differ significantly (statistically) from patients who did not receive antibiotics (OR, 0.88; 95 percent CI, 0.59 to 1.31).

CONCLUSIONS

The treatment goal of primary palatoplasty is the successful repair of the cleft without an oronasal fistula. Administration of preoperative antibiotics did not significantly reduce the odds of subsequent fistula repair within the same Pediatric Health Information System institution following primary palatoplasty.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Management of an Outbreak ofClostridium difficile–Associated Disease Among Geriatric Patients

Objective.

To describe a nosocomial outbreak ofClostridium difficile–associated disease (CDAD).

Design.

A traditional outbreak investigation.

Setting.

Geriatric department of a tertiary care teaching hospital from March through April 2003.

Methods.

The outbreak was detected by theC. difficilesurveillance program of the infection control unit. CDAD was diagnosed by stool culture and fecal toxin A detection with a qualitative rapid immunoassay. Isolates ofC difficilewere serotyped and genotyped using pulsed-field gel electrophoresis.

Results.

The incidence of CDAD increased from 27 cases per 100,000 patient-days in the 6-month period before the outbreak to 99 cases per 100,000 patient-days during the outbreak. This outbreak involved 21 of 92 patients in 4 geriatric wards, which were located at 2 geographically distinct sites and staffed by the same medical team. The mean age of patients was 83 years (range, 71-100 years). Five (24%) of the 21 patients had community-acquired diarrhea, and secondary hospital transmission resulted in 3 clusters involving 16 patients. Serotyping and genotyping were performed on isolates in stool specimens from 19 different patients; 16 of these isolates were serotype A1, whereas 3 displayed profiles different from the outbreak strain. Management of this outbreak consisted in reinforcement of contact isolation precautions for patients with diarrhea, cohorting of infected patients in the same ward, and promotion of hand hygiene. Relapses occurred in 6 (29%) of 21 patients.

Conclusion.

Control of this rapidly developing outbreak of CDAD was obtained with early implementation of cohorting and ward closure and reinforcement of environmental disinfection, hand hygiene, and enteric isolation precautions.

The rise in Clostridium difficile infection incidence among hospitalized adults in the United States: 2001-2010

BACKGROUND

Clostridium difficile infection (CDI) incidence is a growing concern. This study provides national estimates of CDI over 10 years and identifies trends in mortality and hospital length of stay (LOS) among hospitalized adults with CDI.

METHODS

We conducted a retrospective analysis of the US National Hospital Discharge Surveys from 2001-2010. Eligible cases included adults aged ≥ 18 years discharged from a hospital with an ICD-9-CM diagnosis code for CDI (008.45). Data weights were used to derive national estimates. CDI incidence rates were depicted as CDI discharges per 1,000 total adult discharges.

RESULTS

These data represent 2.2 million adult hospital discharges for CDI over the study period. CDI incidence increased from 4.5 CDI discharges per 1,000 total adult discharges in 2001 to 8.2 CDI discharges per 1,000 total adult discharges in 2010. The overall in-hospital mortality rate was 7.1% for the study period. Mortality increased slightly over the study period, from 6.6% in 2001 to 7.2% in 2010. Median hospital LOS was 8 days (interquartile range, 4-14 days), and remained stable over the study period.

CONCLUSIONS

The incidence of CDI among hospitalized adults in the United States nearly doubled from 2001-2010. Furthermore, there is little evidence of improvement in patient mortality or hospital LOS.

A population-based spatio-temporal analysis of Clostridium difficile infection in Queensland, Australia over a 10-year period

OBJECTIVES

To identify the spatio-temporal patterns and environmental factors associated with Clostridium difficile infection (CDI) in Queensland, Australia.

METHODS

Data from patients tested for CDI were collected from 392 postcodes across Queensland between May 2003 and December 2012. A binomial logistic regression model, with CDI status as the outcome, was built in a Bayesian framework, incorporating fixed effects for sex, age, source of the sample (healthcare facility or community), elevation, rainfall, land surface temperature, seasons of the year, time in months and spatially unstructured random effects at the postcode level.

RESULTS

C. difficile was identified in 13.1% of the samples, the proportion significantly increased over the study period from 5.9% in 2003 to 18.8% in 2012. CDI peaked in summer (14.6%) and was at its lowest in autumn (10.1%). Other factors significantly associated with CDI included female sex (OR: 1.08; 95%CI: 1.01-1.14), community source samples (OR: 1.12; 95%CI: 1.05-1.20), and higher rainfall (OR: 1.09; 95%CI: 1.02-1.17). There was no significant spatial variation in CDI after accounting for the fixed effects in the model.

CONCLUSIONS

There was an increasing annual trend in CDI in Queensland from 2003 to 2012. Peaks of CDI were found in summer (December-February), which is at odds with the current epidemiological pattern described for northern hemisphere countries. Epidemiologically plausible explanations for this disparity require further investigation.

Assessing control bundles for Clostridium difficile: a review and mathematical model

Clostridium difficile is the leading cause of infectious diarrhea in hospitalized patients. Integrating several infection control and prevention methods is a burgeoning strategy for reducing disease incidence in healthcare settings. We present an up-to-date review of the literature on ‘control bundles' used to mitigate the transmission of this pathogen. All clinical studies of control bundles reported substantial reductions in disease rates, in the order of 33%–61%. Using a biologically realistic mathematical model we then simulated the efficacy of different combinations of the most prominent control methods: stricter antimicrobial stewardship; the administering of probiotics/intestinal microbiota transplantation; and improved hygiene and sanitation. We also assessed the health gains that can be expected from reducing the average length of stay of inpatients. In terms of reducing the rates of colonization, all combinations had the potential to give rise to marked improvements. For example, halving the number of inpatients on broad-spectrum antimicrobials combined with prescribing probiotics or intestinal microbiota transplantation could cut pathogen carriage by two-thirds. However, in terms of symptomatic disease incidence reduction, antimicrobials, probiotics and intestinal microbiota transplantation proved substantially less effective. Eliminating within-ward transmission by improving sanitation and reducing average length of stay (from six to three days) yielded the most potent symptomatic infection control combination, cutting rates down from three to less than one per 1000 hospital bed days. Both the empirical and theoretical exploration of C. difficile control combinations presented in the current study highlights the potential gains that can be achieved through strategically integrated infection control.

Clostridium difficile exposure as an insidious source of infection in healthcare settings: an epidemiological model

BACKGROUND

Clostridium difficile is the leading cause of infectious diarrhea in hospitalized patients. Its epidemiology has shifted in recent years from almost exclusively infecting elderly patients in whom the gut microbiota has been disturbed by antimicrobials, to now also infecting individuals of all age groups with no recent antimicrobial use.

METHODS

A stochastic mathematical model was constructed to simulate the modern epidemiology of C. difficile in a healthcare setting, and, to compare the efficacies of interventions.

RESULTS

Both the rate of colonization and the incidence of symptomatic disease in hospital inpatients were insensitive to antimicrobial stewardship and to the prescription of probiotics to expedite healthy gut microbiota recovery, suggesting these to be ineffective interventions to limit transmission. Comparatively, improving hygiene and sanitation and reducing average length of stay more effectively reduced infection rates. Although the majority of new colonization events are a result of within-hospital ward exposure, simulations demonstrate the importance of imported cases with new admissions.

CONCLUSIONS

By analyzing a wide range of screening sensitivities, we identify a previously ignored source of pathogen importation: although capturing all asymptomatic as well as symptomatic introductions, individuals who are exposed but not yet colonized will be missed by even a perfectly sensitive screen on admission. Empirical studies to measure the duration of this latent period of infection will be critical to assessing C. difficile control strategies. Moreover, identifying the extent to which the exposed category of individual contributes to pathogen importation should be explicitly considered for all infections relevant to healthcare settings.

Overcoming barriers to effective recognition and diagnosis of Clostridium difficile infection

With the frequency of cases of Clostridium difficile infection (CDI) increasing in many developed countries, accurate and reliable laboratory diagnosis of CDI is more important than ever. However, the diagnosis of CDI has been handicapped by the existence of two reference standards, one of which detects C. difficile toxin (cytotoxin assay) and the other only toxigenic strains (cytotoxigenic culture). Being relatively slow and laborious to perform, these reference methods were largely abandoned as routine diagnostic methods for toxin detection in favour of stand-alone rapid enzyme immunoassays (EIAs), which have suboptimal sensitivity and specificity. The management of CDI is undermined by high rates of both false-positive and false-negative test results. More recently developed nucleic acid amplification tests (NAATs) for toxin gene detection offer improved sensitivity over immunoassays, but fail to discriminate between CDI and asymptomatic colonization with C. difficile, and have clear drawbacks as stand-alone diagnostic tests. Two-step or three-step diagnostic algorithms have been proposed as a solution. In a large study of the effectiveness of currently available tests, a diagnostic algorithm was developed that combines available tests to more effectively distinguish patients with CDI from uninfected patients. This two-test protocol, which is now used in National Health Service laboratories in England, comprises an EIA for glutamate dehydrogenase detection or NAATs for toxin gene detection, followed by a relatively sensitive toxin EIA. This algorithm also identifies 'potential C. difficile excretors', individuals with diarrhoeal samples that contain C. difficile but without demonstrable toxin, who may be a source of transmission of C. difficile to susceptible patients.

Clostridium difficile infection in the inflammatory bowel disease patient

Clostridium difficile infection (CDI) has been increasing in frequency and severity in patients with inflammatory bowel disease (IBD). Population based and single center studies have shown worse clinical outcomes in concomitant CDI and IBD, with several reporting longer length of hospital stay, higher colectomy rates and increased mortality. Clinically, CDI may be difficult to distinguish from an IBD flare and may range from an asymptomatic carrier state to severe life threatening colitis. The traditional risk factors for CDI have included hospitalization, antibiotic use, older age and severe co-morbid disease but IBD patients have several distinct characteristics including younger age, community acquisition, lack of antibiotic exposure, colonic IBD and steroid use. CDI can occur in the small bowel and specifically in ulcerative colitis patients who have had a colectomy and an ileal pouch anal anastomosis. PCR based assays and combination Elisa algorithms have improved the sensitivity and specificity of testing, though in IBD patients have raised clinical questions about how to best manage diarrhea in the setting of possible C. difficile colonization. Treatment modalities for CDI have not been examined in randomized clinical trials in the IBD population. Newer antibiotics, immunotherapy and fecal microbiota transplantation may alter current treatment strategies. This review will focus on the unique epidemiology of CDI in IBD patients, detail clinical disease states, and provide updated diagnostic strategies, prevention and treatment options.

Underestimation of Clostridium difficile infection among clinicians: an international survey

The objective of this investigation was to document clinicians' awareness regarding the incidence and severity of Clostridium difficile-associated diarrhea (CDAD). An international electronic survey was conducted among corresponding authors of articles indexed by PubMed and published during the last 10 years in 'Core Clinical Journals'. A total of 1,163 clinicians answered (response rate 59%); most of the responses were submitted from North America (54.6%), Europe (32.2%), and Asia/Pacific (11.6%). Only 2.2% of the participants answered correctly all four questions, while 14.1% answered all questions incorrectly. Regarding each question, 10.8% of the participants correctly estimated current CDAD treatment failure or recurrence rates to be around 40%, 33.4% correctly estimated the ratio of antibiotic-associated colitis attributed to C. difficile to be around 60%, 72.7% correctly responded that almost all antibiotics are associated with CDAD, and 41.7% correctly responded that any patient is at risk for CDAD. Almost half (44.4%) of the respondents considered CDAD to be underestimated. Participants from North America scored higher than those from Europe or Asia/Pacific (p < 0.001). Participants considering CDAD to be overestimated (3.4%) had the lowest mean score of correct answers. Among a clinically diverse international sample of physicians with academic expertise, there was an inadequate level of awareness of the magnitude and clinical importance of CDAD.

Changing prophylactic antibiotic protocol for reducing Clostridium difficile-associated diarrhoeal infections

PURPOSE

To determine whether a change in prophylactic antibiotic protocol for orthopaedic surgeries may reduce the frequency of Clostridium difficile-associated diarrhoeal infections.

METHODS

Records of 1331 patients who underwent trauma or elective surgeries involving implantation of metalwork were reviewed. 231 trauma and 394 elective patients who received intravenous cefuroxime-based antibiotic prophylaxis between August 2006 and January 2007 were compared with 216 trauma and 490 elective patients who received a single dose of gentamicin and flucloxacillin or teicoplanin for antibiotic prophylaxis between August 2007 and January 2008. Diarrhoeal faecal specimens of 148 (33%) trauma patients and 106 (12%) elective patients were examined. The outcome variables were the rates of C difficile infection and early deep wound infection.

RESULTS

There were 32 cases of C difficile-associated diarrhoeal infection and 28 cases of early deep wound infection. The frequency of C difficile-associated diarrhoeal infection decreased after use of the new antibiotic protocol (from 4 to 1%, p = 0.004), particularly in the trauma patients (from 8 to 3%, p = 0.02); in the elective patients the difference was not significant (from 1 to 0.5%, p = 0.27). The change of antibiotic protocol did not significantly affect the incidence of deep wound infections in the trauma (p = 0.46) or elective (p = 0.90) patients. The rate of C difficile infection was 8-fold higher in the trauma than elective patients, both before and after the change of protocol.

CONCLUSION

Changing antibiotic protocol is one way of reducing the incidence of C difficile-associated diarrhoeal infections in orthopaedic patients, without increasing the rate of deep wound infections.

Clostridium difficile PCR ribotype 027: assessing the risks of further worldwide spread

Highly virulent strains of Clostridium difficile have emerged since 2003, causing large outbreaks of severe, often fatal, colitis in North America and Europe. In 2008–10, virulent strains spread between continents, with the first reported cases of fluoroquinolone-resistant C difficile PCR ribotype 027 in three Asia-Pacific countries and Central America. We present a risk assessment framework for assessing risks of further worldwide spread of this pathogen. This framework first requires identification of potential vehicles of introduction, including international transfers of hospital patients, international tourism and migration, and trade in livestock, associated commodities, and foodstuffs. It then calls for assessment of the risks of pathogen release, of exposure of individuals if release happens, and of resulting outbreaks. Health departments in countries unaffected by outbreaks should assess the risk of introduction or reintroduction of C difficile PCR ribotype 027 using a structured risk-assessment approach.

Diagnostic trends in Clostridium difficile detection in Finnish microbiology laboratories

Due to increased interest directed to Clostridium difficile-associated infections, a questionnaire survey of laboratory diagnostics of toxin-producing C. difficile was conducted in Finland in June 2006. Different aspects pertaining to C. difficile diagnosis, such as requests and criteria used for testing, methods used for its detection, yearly changes in diagnostics since 1996, and the total number of investigations positive for C. difficile in 2005, were asked in the questionnaire, which was sent to 32 clinical microbiology laboratories, including all hospital-affiliated and the relevant private clinical microbiology laboratories in Finland. The situation was updated by phone and email correspondence in September 2008. In June 2006, 28 (88%) laboratories responded to the questionnaire survey; 24 of them reported routinely testing requested stool specimens for C. difficile. Main laboratory methods included toxin detection (21/24; 88%) and/or anaerobic culture (19/24; 79%). In June 2006, 18 (86%) of the 21 laboratories detecting toxins directly from feces, from the isolate, or both used methods for both toxin A (TcdA) and B (TcdB), whereas only one laboratory did so in 1996. By September 2008, all of the 23 laboratories performing diagnostics for C. difficile used methods for both TcdA and TcdB. In 2006, the number of specimens processed per 100,000 population varied remarkably between different hospital districts. In conclusion, culturing C. difficile is common and there has been a favorable shift in toxin detection practice in Finnish clinical microbiology laboratories. However, the variability in diagnostic activity reported in 2006 creates a challenge for national monitoring of the epidemiology of C. difficile and related diseases.

Survey of prophylactic antibiotic use amongst UK cochlear implant surgeons

Cochlear implant patients are at an increased risk of pneumococcal meningitis. Recent government guidelines require all implant patients to undergo pneumococcal vaccination. The guidelines also suggest antibiotic prophylaxis but no clear guidelines regarding which antibiotic to use or for how long were issued.We asked each implant centre within the UK to describe their antibiotic protocol for cochlear implantation.Our results have showed that 100% of UK implant surgeons use antibiotic prophylaxis. The type of antibiotic and duration vary significantly between centres. Interestingly, however, the regimes followed by most practices do not adhere to surgical principles of antibiotic prophylaxis.

Type IV pili and the CcpA protein are needed for maximal biofilm formation by the gram-positive anaerobic pathogen Clostridium perfringens

The predominant organizational state of bacteria in nature is biofilms. Biofilms have been shown to increase bacterial resistance to a variety of stresses. We demonstrate for the first time that the anaerobic gram-positive pathogen Clostridium perfringens forms biofilms. At the same concentration of glucose in the medium, optimal biofilm formation depended on a functional CcpA protein. While the ratio of biofilm to planktonic growth was higher in the wild type than in a ccpA mutant strain in middle to late stages of biofilm development, the bacteria shifted from a predominantly biofilm state to planktonic growth as the concentration of glucose in the medium increased in a CcpA-independent manner. As is the case in some gram-negative bacteria, type IV pilus (TFP)-dependent gliding motility was necessary for efficient biofilm formation, as demonstrated by laser confocal and electron microscopy. However, TFP were not associated with the bacteria in the biofilm but with the extracellular matrix. Biofilms afforded C. perfringens protection from environmental stress, including exposure to atmospheric oxygen for 6 h and 24 h and to 10 mM H(2)O(2) for 5 min. Biofilm cells also showed 5- to 15-fold-increased survival over planktonic cells after exposure to 20 microg/ml (27 times the MIC) of penicillin G for 6 h and 24 h, respectively. These results indicate C. perfringens biofilms play an important role in the persistence of the bacteria in response to environmental stress and that they may be a factor in diseases, such as antibiotic-associated diarrhea and gas gangrene, that are caused by C. perfringens.

A new formulation of tolevamer, a novel nonantibiotic polymer, is safe and well-tolerated in healthy volunteers: a randomized phase I trial

AIMS

To evaluate the safety and tolerability of a new oral solution formulation of tolevamer potassium sodium, a nonantibiotic polymer that binds Clostridium difficile toxins A and B.

METHODS

This phase 1 randomized, double-blind, placebo-controlled study evaluated four doses of tolevamer potassium sodium in 40 healthy volunteers using a sequential dose escalation paradigm and doses of 6, 9, 12 and 15 g day(-1) for 9 days. Within each 10 patient cohort, eight patients received active treatment and two matching placebo. Placebo subjects were pooled to provide eight per arm. All subjects received three times daily dosing on days 2-8 as well as a loading dose (a single dose equal to the total daily dose) either on day 1 or day 9.

RESULTS

All 40 subjects completed the study per protocol. Treatment-emergent adverse events (TEAEs) were generally mild, transient, and resolved without sequelae. There were no serious AEs or deaths. There was no relationship detected between dose and the incidence of TEAEs, whether drug-related (all gastrointestinal disorders) or not. No clinically significant changes in laboratory parameters, including serum and urinary potassium concentrations, vital signs, and results of physical examination, were observed. A small but statistically significant reduction in 24 h urine potassium excretion was seen in the 15 g day(-1) dose group, and on day 10 in the 6 g day(-1) group.

CONCLUSIONS

Tolevamer oral solution administered for 9 days at total daily doses up to 15 g, with loading doses of up to 15 g, was generally safe and well-tolerated in healthy volunteers.

Prophylactic antibiotics and surgery for primary clefts

There are currently no evidence-based guidelines about the use of antibiotic prophylaxis in repair of cleft lip and palate. After the designation of regional cleft centres in the UK, a postal questionnaire was sent to cleft surgeons in 2004 to enquire about the use of routine antibiotic prophylaxis for primary repair of cleft lip and palate. The results showed a lack of consensus and wide disparity among centres. The findings show that there is a need for a random control clinical trial to establish national recommendations for the rational use of prophylactic antibiotics in primary cleft surgery.

Detection of Clostridium difficile in stool samples from patients in the early period after liver transplantation

OBJECTIVE

We examined the frequency of detection of Clostridium difficile (CD) toxins compared with the recovery of C. difficile in stool specimen cultures among orthotopic liver transplant (OLT) patients with nosocomial diarrhea in the early period.

MATERIALS AND METHODS

The study included stool samples obtained during the first 30 days after OLT in adults who were suspected of CD-associated diseases. The identification of cultured CD strains was performed by standard microbiological methods. The presence of CD toxins was assayed using a commercial immunoassay.

RESULTS

All patients were followed prospectively for CD infections from the date of OLT for the first 4 weeks after surgery. Among 54 samples, 16.7% were culture-positive for CD. CD toxins were tested on 54 samples, yielding 63% toxin-positive samples and 30% toxin- and culture-negative results. In the first week after OLT, samples from 19 patients were subjected to CD investigation. Among 19 samples positive for toxin, 52.6% of all samples were culture-negative. We analyzed 35 samples from the second to the fourth week after OLT in 31 recipients. Among 35 samples, 68.6% and 25.7% were positive for CD toxin and for culture, while 20% of samples were negative for toxin and culture.

CONCLUSION

In our study, 63% of samples were toxin-positive with 16.7% yielding growth of CD and 30% being negative for toxins and cultures.

Nosocomial diarrhoea

Toroviruses have been reported as a new cause of nosocomial viral diarrhoea, and the role of astroviruses has been further elucidated. Polymerase chain reaction methods promise to improve the diagnosis and understanding of the aetiology and control of hospital-acquired viral gastroenteritis. A clearer picture of the impact and extent of Clostridium difficile diarrhoea has emerged, and several control measures have been described. An epidemic Clostridium difficile strain and toxin A-deficient strains have been reported. There is growing evidence that enterotoxin-producing Clostridium perfringens can also cause antibiotic-associated diarrhoea.

Systematic review of antimicrobial drug prescribing in hospitals

Standardizing methods and reporting could improve interventions that reduce Clostridium difficile–associated diarrhea and antimicrobial drug resistance.

Prudent prescribing of antimicrobial drugs to hospital inpatients may reduce incidences of antimicrobial drug resistance and healthcare-associated infection. We reviewed the literature from January 1980 to November 2003 to identify rigorous evaluations of interventions to improve hospital prescribing of antimicrobial drugs. We identified 66 studies with interpretable data, of which 16 reported 20 microbiologic outcomes: gram-negative resistant bacteria, 10 studies; Clostridium difficile–associated diarrhea, 5 studies; vancomycin-resistant enterococci, 3 studies; and methicillin-resistant Staphylococcus aureus, 2 studies. Four studies provided strong evidence that the intervention changed microbial outcomes with low risk for alternative explanations, 8 studies provided less convincing evidence, and 4 studies provided no evidence. The strongest and most consistent evidence was for C. difficile–associated diahrrea, but we were able to analyze only the immediate impact of interventions because of nonstandardized durations of follow-up. The ability to compare results of studies could be substantially improved by standardizing methods and reporting.

Systematic Review of Antimicrobial Drug Prescribing in Hospitals

Prudent prescribing of antimicrobial drugs to hospital inpatients may reduce incidences of antimicrobial drug resistance and healthcare-associated infection. We reviewed the literature from January 1980 to November 2003 to identify rigorous evaluations of interventions to improve hospital prescribing of antimicrobial drugs. We identified 66 studies with interpretable data, of which 16 reported 20 microbiologic outcomes: gram-negative resistant bacteria, 10 studies; Clostridium difficile-associated diarrhea, 5 studies; vancomycin-resistant enterococci, 3 studies; and methicillin-resistant Staphylococcus aureus, 2 studies. Four studies provided strong evidence that the intervention changed microbial outcomes with low risk for alternative explanations, 8 studies provided less convincing evidence, and 4 studies provided no evidence. The strongest and most consistent evidence was for C. difficile-associated diarrhea, but we were able to analyze only the immediate impact of interventions because of nonstandardized durations of follow-up. The ability to compare results of studies could be substantially improved by standardizing methods and reporting.

Quorum sensing in Clostridium difficile: analysis of a luxS-type signalling system

The increasing incidence of Clostridium difficile-associated disease, and the problems associated with its control, highlight the need for additional countermeasures. The attenuation of virulence through the blockade of bacterial cell-to-cell communication (quorum sensing) is one potential therapeutic target. Preliminary studies have shown that C. difficile produces at least one potential signalling molecule. Through the molecule's ability to induce bioluminescence in a Vibrio harveyi luxS reporter strain, it has been shown to correspond to autoinducer 2 (AI-2). In keeping with this observation, a homologue of luxS has been identified in the genome of C. difficile. Adjacent to luxS(Cd) a potential transcriptional regulator and sensor kinase, rolA and rolB, have been located. RT-PCR has been used to confirm the genetic organization of the luxS(Cd) locus. While AI-2 production has not been blocked so far using antisense technology, AI-2 levels could be modulated by controlling expression of the putative transcriptional regulator rolA. RolA, therefore, acts as a negative regulator of AI-2 production. Finally, it has been shown that the exogenous addition of AI-2 or 4-hydroxy-5-methyl-3(2H) furanone has no discernible effect on the production of toxins by C. difficile.

Antibiotic prescribing policy and Clostridium difficile diarrhoea

BACKGROUND

Broad-spectrum antibiotics, particularly intravenous cephalosporins, are associated with Clostridium difficile diarrhoea. Diarrhoea due to C. difficile is a growing problem in hospitals, especially among elderly patients.

AIM

To establish whether changing an antibiotic policy with the aim of reducing the use of injectable cephalosporins leads to a reduction in the incidence of C. difficile diarrhoea in elderly patients.

DESIGN

Retrospective analysis.

METHODS

A group of patients who were subject to the new antibiotic policy from the period following July 2000, were compared with patients who were admitted prior to July 2000 and were not subject to the new policy. Infections, antibiotic prescriptions and mortality rates were determined from case notes, and C. difficle diarrhoea rates from microbiological data.

RESULTS

Intravenous cephalosporin use fell from 210 to 28 defined daily doses (p < 0.001) following the change in antibiotic policy, with a corresponding increase in piperacillin-tazobactam (p < 0.001) and moxifloxacin (p < 0.001) use. The new policy led to a significant reduction in C. difficile diarrhoea cases. The relative risk of developing C. difficile infection with the old policy compared to the new policy was 3.24 (95%CI 1.07-9.84, p = 0.03).

DISCUSSION

The antibiotic policy was successfully introduced into an elderly care service. It reduced both intravenous cephalosporin use and C. difficile diarrhoea.

Gene transfer intoClostridium difficileCD630 and characterisation of its methylase genes

Ignorance of pathogenesis in Clostridium difficile may be attributable to a lack of effective genetic tools. We have now shown that oriT-based shuttle vectors may be conjugated from Escherichia coli donors to the C. difficile strain CD630, at frequencies of around 10(-6) transconjugants per donor cell. Transfer is unaffected by either sequences present on the vector or its methylation status. Whilst the genome of this strain carries five methylase genes, there is no in silico or experimental evidence for cognate restriction enzymes. It would seem that the identified methylases do not participate in restriction-modification, and must, therefore, fulfil another role. A similar situation most likely applies to other clostridia.

Acute gastroenteritis in children : what role for antibacterials?

The aim of this article is to define the currently accepted role of antibacterials in the treatment of acute gastroenteritis in children. Most cases of acute gastroenteritis in children are viral, self-limited, and need only supportive treatment. Appropriate fluid and electrolyte therapy, with close attention to nutrition, remain central to therapy.Antibacterial therapy serves as an adjunct, to shorten the clinical course, eradicate causative organisms, reduce transmission, and prevent invasive complications. Selection of antibacterials to use in acute bacterial gastroenteritis is based on clinical diagnosis of the likely pathogen prior to definitive laboratory results. Antibacterial therapy should be restricted to specific bacterial pathogens and disease presentations. In general, infections with Shigella spp. and Vibrio cholera should usually be treated with antibacterials, while antibacterials are only used in severe unresponsive infections with Salmonella, Yersinia, Aeromonas, Campylobacter, Plesiomonas spp., and Clostridium difficile. Antibacterials should be avoided in enterohemorrhagic Escherichia coli infection. However, empiric therapy may be appropriate in the presence of a severe illness with bloody diarrhea and stool leucocytes, particularly in infancy and the immunocompromised. The benefits and risks of adverse drug reactions should be weighed before prescribing antibacterials. Moreover, a major concern is the emergence of antibacterial-resistant strains due to the widespread use of antibacterial agents.

Gastrointestinal disorders and the critically ill. Clostridium difficile infection and pseudomembranous colitis

Clostridium difficile causes a spectrum of diseases ranging from diarrhoea to pseudomembranous colitis, primarily in the hospitalized elderly, although community-acquired infection is probably under-documented. Host factors are increasingly recognized as critical determinants of disease expression. Exposure to antibiotics, particularly those adversely affecting anaerobic gut flora, appears to create a niche which is exploited by C. difficile. Several retrospective and intervention studies have indicated that third-generation cephalosporins have a high propensity to induce C. difficile diarrhoea. Conversely, some broad-spectrum antibiotics, including ureidopenicillins (e.g. piperacillin-tazobactam) and ciprofloxacin, are less likely to induce C. difficile infection. Effective control of C. difficile in the hospital requires both antibiotic control and prevention of environmental seeding and bacterial spread. Epidemic C. difficile strains are widely distributed in the hospital environment, both as a cause and result of nosocomial diarrhoea. Current treatment options are antibiotic-based, which is less than ideal. Although many biotherapeutic approaches have been tried few have shown real benefit.

Clostridium difficile-associated diarrhea: epidemiological data from Western Australia associated with a modified antibiotic policy

The incidence of Clostridium difficile-associated diarrhea (CDAD) has increased dramatically in hospitals worldwide during the past 2 decades. In Western Australia, this increase was most obvious during the 1980s, when there was also an increase in the use of third-generation cephalosporin antibiotics. A study of the epidemiology of CDAD and the use of third-generation cephalosporins during 1993-2000 was undertaken. From 1993 through 1998, the incidence of CDAD remained relatively stable (2-3 cases per 1000 discharges annually). Then, a significant decrease in the incidence occurred, from 2.09 cases per 1000 discharges (95% confidence interval [CI], 1.71-2.47) in 1998 to 0.87 cases per 1000 discharges (95% CI, 0.63-1.11) in 1999 (P<.0001); this decrease persisted into 2000. A decrease in third-generation cephalosporin use occurred during the period of the study because of changes in the prescribing policy. These findings suggest that a reduction in the use of third-generation cephalosporins can reduce the occurrence of CDAD.

Saturday night fever: finding and controlling the source of sepsis in critical illness

Fever is a daily concern in the intensive care unit. Although about half of all febrile cases are due to non-infectious causes, fear of sepsis frequently leads to diagnostic tests and escalation of therapy, including broadening antibiotic therapy. Using a case to illustrate this dilemma, we discuss the commonest non-infectious and infectious causes of fever, and suggests approaches to their management. Any unexplained fever in intensive care unit patients warrants investigation, which includes complete clinical assessment and blood cultures. When the source of fever is not immediately apparent, non-infectious and infectious causes should be considered. If stable, non-neutropenic patients should be monitored before further tests or empiric antibiotics are started. In an era of rapid emergence and spread of antimicrobial-resistant pathogens and intense scrutiny of resources, optimal diagnosis and management of patients with suspected infection entails much more than the escalation of antimicrobial therapy.

Morbidity, mortality, and healthcare burden of nosocomial Clostridium difficile-associated diarrhea in Canadian hospitals

OBJECTIVE

To assess the healthcare burden, morbidity, and mortality of nosocomial Clostridium difficile-associated diarrhea (N-CDAD) in Canadian hospitals.

DESIGN

Laboratory-based prevalence study.

SETTING

Nineteen acute-care Canadian hospitals belonging to the Canadian Hospital Epidemiology Committee surveillance program.

PATIENTS

Hospitalized patients in the participating centers.

METHODS

Laboratory-based surveillance was conducted for C. difficile toxin in stool among 19 Canadian hospitals from January to April 1997, for 6 continuous weeks or until 200 consecutive diarrhea stool samples had been tested at each site. Patients with N-CDAD had to fulfill the case definition. Data collected for each case included patient demographics, length of stay, extent of diarrhea, complications of CDAD, CDAD-related medical interventions, patient outcome, and details of death.

RESULTS

We found that 371 (18%) of 2,062 tested patients had stools with positive results for C difficile toxin, of whom 269 (13%) met the case definition for nosocomial CDAD. Of these, 250 patients (93%) had CDAD during their hospitalization, and 19 (7%) were readmitted because of CDAD (average readmission stay, 13.6 days). Forty-one patients (15.2%) died, of whom 4 (1.5% of the total) were considered to have died directly or indirectly of N-CDAD. The following N-CDAD-related morbidity was noted: dehydration, 3%; hypokalemia, 2%; gastrointestinal hemorrhage requiring transfusion, 1%; bowel perforation, 0.4%; and secondary sepsis, 0.4%. The cost of N-CDAD readmissions alone was estimated to be a minimum of $128,200 (Canadian dollars) per year per facility.

CONCLUSION

N-CDAD is a common and serious nosocomial infectious complication in Canada, is associated with substantial morbidity and mortality, and imposes an important financial burden on healthcare institutions.

Prospective evaluation of environmental contamination by Clostridium difficile in isolation side rooms

We determined prospectively the frequency, persistence and molecular epidemiology of Clostridium difficile environmental contamination after detergent-based cleaning in side rooms used to isolate patients with C. difficile diarrhoea. Approximately one-quarter of all environmental sites in side rooms sampled over four-week periods were contaminated with C. difficile. The overall side room prevalence of environmental C. difficile declined from 35% initially, to 24% in week 2, 18% in week 3, and 16% in week 4. The bed frame was the most common site from which C. difficile was recovered, although the floor was the most contaminated site in terms of total numbers of colonies. C. difficile was recovered significantly more frequently from swabs plated directly on to C. difficile selective media containing lysozyme than from enrichment broth (P< 0.001), emphasizing the benefit of lysozyme supplementation. The great majority of C. difficile isolates (87% of all isolates, 84% of patient isolates) was indistinguishable from the UK epidemic strain (PCR ribotype 1). It thus could not be determined whether environmental contamination was a cause or a consequence of diarrhoea. Our findings highlight the need for improved approaches to hospital environmental hygiene, and call into question current UK guidelines that recommend detergent-based cleaning to remove environmental C. difficile. In particular, improved cleaning of frequently touched sites in the immediate bed space area is required.

Association between antibody response to toxin A and protection against recurrent Clostridium difficile diarrhoea

BACKGROUND

We have reported that symptom-free carriers of Clostridium difficile have a systemic anamnestic immune response to toxin A. The aim of this study was to determine whether an acquired immune response to toxin A, during an episode of C. difficile diarrhoea, influences risk of recurrence.

METHODS

We prospectively studied 63 patients with nosocomial C. difficile diarrhoea. Serial serum IgA, IgG, and IgM concentrations against C. difficile toxin A, toxin B, or non-toxin antigens were measured by ELISA. Individuals were followed for 60 days.

FINDINGS

19 patients died (30%). Of the 44 who survived, 22 had recurrent C. difficile diarrhoea. Patients with a single episode of C. difficile diarrhoea (n=22) had higher concentrations of serum IgM against toxin A on day 3 of their first episode of diarrhoea than those with recurrent diarrhoea (n=22, p=0.004). On day 12, serum IgG values against toxin A were higher in patients who had a single episode of diarrhoea (n=7) than in those who subsequently had recurrent diarrhoea (n=9, p=0.009). The odds ratio for recurrence associated with a low concentration of serum IgG against toxin A, measured 12 days after onset of C. difficile diarrhoea, was 48.0 (95% CI 3.5-663).

INTERPRETATION

A serum antibody response to toxin A, during an initial episode of C. difficile diarrhoea, is associated with protection against recurrence.

Clinical evaluation and management of acute severe colitis

This review concentrates on the clinical evaluation, imaging, therapy, and prognostic factors in acute severe colitis of idiopathic as well as infectious origin. Older concepts as well as more recent are critically scrutinized.

The rise of Clostridium difficile: the effect of length of stay, patient age and antibiotic use

Hospitals in the UK have recently seen a marked increase in C. difficile for reasons which are unclear. Reduced standards of hygiene, increasingly elderly patients, greater cephalosporin use and longer hospital stay have been suggested. We retrospectively studied all cases of C. difficile diarrhoea at Princess Margaret Hospital, Swindon, over two years. Cephalosporins, patient age and LOS appeared unrelated to the rise in C. difficile; penicillins and macrolides were related. Our policy of using amoxycillin and clarithromycin for community-acquired pneumonia coincided with this study and may explain the observed rise in C. difficile.

Fever in the ICU

Fever is a common problem in ICU patients. The presence of fever frequently results in the performance of diagnostic tests and procedures that significantly increase medical costs and expose the patient to unnecessary invasive diagnostic procedures and the inappropriate use of antibiotics. ICU patients frequently have multiple infectious and noninfectious causes of fever, necessitating a systematic and comprehensive diagnostic approach. Pneumonia, sinusitis, and blood stream infection are the most common infectious causes of fever. The urinary tract is unimportant in most ICU patients as a primary source of infection. Fever is a basic evolutionary response to infection, is an important host defense mechanism and, in the majority of patients, does not require treatment in itself. This article reviews the common infectious and noninfectious causes of fever in ICU patients and outlines a rational approach to the management of this problem.

Value of lysozyme agar incorporation and alkaline thioglycollate exposure for the environmental recovery of Clostridium difficile

Clostridium difficile is an increasingly prevalent nosocomial pathogen. Environmental contamination by spores is believed to be a major factor propagating the spread of C. difficile. Various approaches including the use of bile salts have been described to enhance the recovery of C. difficile from clinical and environmental specimens. We found that lysozyme (5 mg/L) incorporated into a selective medium containing bile salts significantly increased the recovery of C. difficile from swabs of 197 environmental sites (11% versus 24% samples positive, P< 0.01). Furthermore, in a separate series of experiments additional use of cooked meat broth enrichment significantly enhanced the recovery of C. difficile (35% versus 45%, P = 0.009). Conversely, we found that pre-exposure to alkaline thioglycollate did not improve the yield of C. difficile. Lysozyme incorporation markedly increases the recovery of C. difficile from environmental samples probably by stimulation of spore germination. Our findings suggest that previous attempts to determine the level of environmental C. difficile contamination have markedly underestimated the true prevalence of this pathogen.

Epidemiology of nosocomial clostridium difficile diarrhoea

Clostridium difficile is a frequent and clinically important cause of diarrhoea that has been strongly but not exclusively associated with the hospital setting. The vast majority of cases of C. difficile diarrhoea are associated with antecedent treatment with antibiotics, of which cephalosporins and clindamycin appear to pose the highest risk. Within hospitals and chronic-care facilities, cross-infection of C. difficile has been related to transient carriage on hands of healthcare workers and contamination of diverse environmental surfaces, including electronic rectal thermometers. Prospective epidemiologic studies have demonstrated that acquisition of C. difficile is common in hospitalized patients. Although colonized patients contribute to nosocomial transmission of C. difficile, symptom-free carriage of C. difficile appears to reduce risk of subsequent development of C. difficile diarrhoea. Antimicrobial treatment with oral metronidazole or vancomycin to attempt to eradicate symptomless carriage is not recommended. Measures to control nosocomial C. difficile diarrhoea have focused on improved handwashing, use of barrier precautions with single rooms for symptomatic patients, reduction of environmental contamination, and antibiotic restriction. Restricting clindamycin has been particularly successful in terminating outbreaks of C. difficile diarrhoea associated with its use. The epidemiologic features of C. difficile and strategies for control are similar to those for micro-organisms that have acquired antimicrobial resistance. C. difficile may be indirectly or directly contributing to spread of resistant organisms, for instance, by causing diarrhoea and thereby enhancing environmental contamination with other gastrointestinal flora such as vancomycin-resistant enterococci. Thus, a consideration of C. difficile in the larger context of the world-wide spread of antibiotic resistance offers useful insights that may help form the basis for the development of more effective control measures.