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

Significant impact of terminal room cleaning with bleach on reducing nosocomial Clostridium difficile

BACKGROUND

We were alerted to increased rates of Clostridium difficile-positive tests at all 3 hospitals in our health care system by MedMined Data Mining Surveillance Service, CareFusion (San Diego, CA). In response, an intervention of terminal room cleaning with dilute bleach was instituted to decrease the amount of C difficile environmental spore contamination from patients with C difficile infection (CDI).

METHODS

The intervention consisted of replacing quaternary ammonium compound as a room cleaning agent with dilute bleach to disinfect rooms of patients with CDI upon discharge. All surfaces, floor to ceiling were wiped with dilute bleach applied with towels to thoroughly wet the surfaces. Daily room cleaning remained unchanged. Patients remained on C difficile contact isolation precautions until discharge. To determine the effectiveness of this program, rates of nosocomial CDI for all 3 hospitals were determined using the MedMined Virtual Surveillance Interface for 10 months prior to and 2 years after the cleaning intervention. Statistical significance was determined using Poisson regression analysis.

RESULTS

There was a 48% reduction in the prevalence density of C difficile after the bleaching intervention (95% confidence interval: 36%-58%, P < .0001).

CONCLUSION

The implementation of a thorough, all-surface terminal bleach cleaning program in the rooms of patients with CDI has made a sustained, significant impact on reducing the rate of nosocomial CDI in our health care system.

Performance of ultramicrofibre cleaning technology with or without addition of a novel copper-based biocide

This study compared the bacterial removal performance of ultramicrofibre cloths and mops (UMF) moistened with water (UMF+water), with those moistened with a novel copper-based biocide (UMF+CuWB50, 300ppm) in several working hospital environments, specifically accident and emergency (A&E) and three other wards. A total of 13 defined sampling sites (10 sites per ward) were sampled in order to retrieve, culture, and enumerate total viable (bacterial) counts (TVC) for each site. We sampled 1h before, and 1 and 4h after, cleaning three times per week. The trial ran for 7 weeks. Two wards were cleaned with UMF+water for 3 weeks, and UMF+CuWB50 for 4 weeks. The reverse applied to the other two wards in a cross-over design fashion, to eliminate ward- and time-specific bias. Multivariate statistical analyses were used to establish extent and significance of any perceived differences, and to eliminate the effects of potential confounders. Cleaning with UMF+water reduced TVC on the test surfaces by 30%, whereas cleaning with TVC+CuWB50 reduced TVC by 56%. CuWB50 had two separate effects; a direct antibacterial effect (evident shortly after cleaning), and a residual antibacterial effect that lasted approximately 2 weeks. The residual effect requires regular application of CuWB50 if it is to persist. This 'real life' hospital implementation study demonstrates encouraging microbiological cleaning performance for UMF, which is further enhanced with CuWB50.

Comparison of the efficacy of a hydrogen peroxide dry-mist disinfection system and sodium hypochlorite solution for eradication of Clostridium difficile spores

OBJECTIVE

To compare a hydrogen peroxide dry-mist system and a 0.5% hypochlorite solution with respect to their ability to disinfect Clostridium difficile-contaminated surfaces in vitro and in situ.

DESIGN

Prospective, randomized, before-after trial.

SETTING

Two French hospitals affected by C. difficile.

INTERVENTION

In situ efficacy of disinfectants was assessed in rooms that had housed patients with C. difficile infection. A prospective study was performed at 2 hospitals that involved randomization of disinfection processes. When a patient with C. difficile infection was discharged, environmental contamination in the patient's room was evaluated before and after disinfection. Environmental surfaces were sampled for C. difficile by use of moistened swabs; swab samples were cultured on selective plates and in broth. Both disinfectants were tested in vitro with a spore-carrier test; in this test, 2 types of material, vinyl polychloride (representative of the room's floor) and laminate (representative of the room's furniture), were experimentally contaminated with spores from 3 C. difficile strains, including the epidemic clone ribotype 027-North American pulsed-field gel electrophoresis type 1.

RESULTS

There were 748 surface samples collected (360 from rooms treated with hydrogen peroxide and 388 from rooms treated with hypochlorite). Before disinfection, 46 (24%) of 194 samples obtained in the rooms randomized to hypochlorite treatment and 34 (19%) of 180 samples obtained in the rooms randomized to hydrogen peroxide treatment showed environmental contamination. After disinfection, 23 (12%) of 194 samples from hypochlorite-treated rooms and 4 (2%) of 180 samples from hydrogen peroxide treated rooms showed environmental contamination, a decrease in contamination of 50% after hypochlorite decontamination and 91% after hydrogen peroxide decontamination (P < .005). The in vitro activity of 0.5% hypochlorite was time dependent. The mean (+/-SD) reduction in initial log(10) bacterial count was 4.32 +/- 0.35 log(10) colony-forming units after 10 minutes of exposure to hypochlorite and 4.18 +/- 0.8 log(10) colony-forming units after 1 cycle of hydrogen peroxide decontamination.

CONCLUSION

In situ experiments indicate that the hydrogen peroxide dry-mist disinfection system is significantly more effective than 0.5% sodium hypochlorite solution at eradicating C. difficile spores and might represent a new alternative for disinfecting the rooms of patients with C. difficile infection.

A nosocomial outbreak of norovirus infection masquerading as clostridium difficile infection

Noroviruses (NoVs) are increasingly being recognized as important enteric pathogens. At a university-based hospital, we investigated a nosocomial outbreak of NoV infection that was originally attributed to Clostridium difficile. We describe here the unique challenges of the identification of NoVs as the true etiologic pathogen in an outbreak occurring in a health care setting, where C. difficile infection is endemic, as well as the important lessons learned.

Spatio-temporal stochastic modelling of Clostridium difficile

Clostridium difficile-associated diarrhoea (CDAD) occurs sporadically or in small discrete outbreaks. Stochastic models may help to inform hospital infection control strategies. Bayesian framework using data augmentation and Markov chain Monte Carlo methods were applied to a spatio-temporal model of CDAD. Model simulations were validated against 17 months of observed data from two 30-bedded medical wards for the elderly. Simulating the halving of transmission rates of C. difficile from other patients and the environment reduced CDAD cases by 15%. Doubling the rate at which patients become susceptible increased predicted CDAD incidence by 63%. By contrast, doubling environmental load made hardly any difference, increasing CDAD incidence by only 3%. Simulation of different interventions indicates that for the same effect size, reducing patient susceptibility to infection is more effective in reducing the number of CDAD cases than lowering transmission rates.

Activity of a dry mist hydrogen peroxide system against environmental Clostridium difficile contamination in elderly care wards

Clostridium difficile causes serious healthcare-associated infections. Infection control is difficult, due in part to environmental contamination with C. difficile spores. These spores are relatively resistant to cleaning and disinfection. The activity of a dry mist hydrogen peroxide decontamination system (Sterinis) against environmental C. difficile contamination was assessed in three elderly care wards. Initial sampling for C. difficile was performed in 16 rooms across a variety of wards and specialties, using Brazier's CCEY (cycloserine-cefoxitin-egg yolk) agar. Ten rooms for elderly patients (eight isolation and two sluice rooms) were then resampled following dry mist hydrogen peroxide decontamination. Representative isolates of C. difficile were typed by polymerase chain reaction ribotyping. C. difficile was recovered from 3%, 11% and 26% of samples from low, medium and high risk rooms, respectively. In 10 high risk elderly care rooms, 24% (48/203) of samples were positive for C. difficile, with a mean of 6.8 colony-forming units (cfu) per 10 samples prior to hydrogen peroxide decontamination. Ribotyping identified the presence of the three main UK epidemic strains (ribotypes 001, 027 and 106) and four rooms contained mixed strains. After a single cycle of hydrogen peroxide decontamination, only 3% (7/203) of samples were positive (P<0.001), with a mean of 0.4 cfu per 10 samples ( approximately 94% reduction). The Sterinis hydrogen peroxide system significantly reduced the extent of environmental contamination with C. difficile in these elderly care rooms. This relatively quick and user-friendly technology might be a more reliable method of terminally disinfecting isolation rooms, following detergent cleaning, compared to the manual application of other disinfectants.

Infection control measures to limit the spread of Clostridium difficile

Clostridium difficile-associated diarrhoea (CDAD) presents mainly as a nosocomial infection, usually after antimicrobial therapy. Many outbreaks have been attributed to C. difficile, some due to a new hyper-virulent strain that may cause more severe disease and a worse patient outcome. As a result of CDAD, large numbers of C. difficile spores may be excreted by affected patients. Spores then survive for months in the environment; they cannot be destroyed by standard alcohol-based hand disinfection, and persist despite usual environmental cleaning agents. All these factors increase the risk of C. difficile transmission. Once CDAD is diagnosed in a patient, immediate implementation of appropriate infection control measures is mandatory in order to prevent further spread within the hospital. The quality and quantity of antibiotic prescribing should be reviewed to minimise the selective pressure for CDAD. This article provides a review of the literature that can be used for evidence-based guidelines to limit the spread of C. difficile. These include early diagnosis of CDAD, surveillance of CDAD cases, education of staff, appropriate use of isolation precautions, hand hygiene, protective clothing, environmental cleaning and cleaning of medical equipment, good antibiotic stewardship, and specific measures during outbreaks. Existing local protocols and practices for the control of C. difficile should be carefully reviewed and modified if necessary.

UV-visible marker confirms that environmental persistence of Clostridium difficile spores in toilets of patients with C. difficile-associated diarrhea is associated with lack of compliance with cleaning protocol.e

Background

An ultraviolet visible marker (UVM) was used to assess the cleaning compliance of housekeeping staff for toilets in a tertiary healthcare setting.

Methods

The UVM was applied to the toilets of patients who were on isolation precautions due to Clostridium difficile-associated diarrhea (CDAD) as well as for patients who were not on isolation precautions. Cleaning was visually scored using a numeric system where 0, 1, 2, and 3 represented; no, light, moderate or heavy residual UVM. Rodac plates containing CDMN selective agar were used to test for the presence of C. difficile on the surfaces of patient's toilets.

Results

Despite twice daily cleaning for the toilets of patients who were on CDAD isolation precautions, the average cleaning score was 1.23 whereas the average cleaning score for toilets of patients not on isolation precautions was 0.9. Even with optimal cleaning (UVM score of 0) C. difficile was detected from 33% of the samples taken from toilets of patients with CDAD (4% detection in toilet samples from patients who had diarrhea not due to CDAD).

Conclusion

Our data demonstrated the value of UVM for monitoring the compliance of housekeeping staff with the facility's toilet cleaning protocol. In addition to providing good physical cleaning action, agents with some sporicidal activity against C. difficile may be needed to effectively reduce the environmental reservoir.

Designing a protocol that eliminates Clostridium difficile: a collaborative venture

BACKGROUND

Clostridium difficile is a health care-associated pathogen that is difficult to eradicate in the health care environment through the use of common hospital disinfectants. Many of these disinfectants fail to inactivate C difficile spores, which can result in patient-to-patient transmission. This study demonstrates that the use of 10% hypochlorite solution, along with interventions, reduced the incidence of health care-associated C. difficile infection.

METHODS

A case-only study was conducted over a 24-month period. Interventions used to reduce the incidence of health care-associated C difficile included 10% hypochlorite disinfection, soap and water hand hygiene, contact isolation for suspected and confirmed cases, educational tool for patients and visitors, daily isolation rounds, automated report functions, and standardized nursing unit isolation processes. The microbiology method that was used to isolate the C difficile organism for DNA typing included a minimum of 1 mL of stool placed in a conical screw top tube, and then an equal volume of 95% ethyl alcohol was added to the tube. Prereduced blood agar plates were inoculated with the treated and untreated specimen. Plates were incubated anaerobically for 48 hours at 37 degrees C. Plates were examined for gray, flat colonies and gram stains performed; further testing was performed only on gram-positive rods.

RESULTS

A 66% reduction in the number of health care-associated C difficile cases was achieved during the study. A total of 25 isolates was DNA typed per pulse-field gel electrophoresis. Two distinct genetic patterns were identified. Results yielded that the Florida isolates also had the epidemic strain of the organisms that was noted in Quebec, Canada and other parts of the United States.

CONCLUSION

A combination of automated daily isolation reports, use of a standardized methodology for isolation rounds, as well as development of a 10% hypochlorite disinfection protocol resulted in a dramatic decrease in health care-associated C difficile cases. Weekly nursing director reports and daily rounds by nursing leadership keep the direct line supervisors abreast of infection control issues on their respective nursing units. The addition of the dual-chamber bleach container ensured that the proper dilution was achieved when disinfecting reusable equipment.

Prevalence of Clostridium difficile environmental contamination and strain variability in multiple health care facilities

BACKGROUND

Clostridium difficile spores can contaminate the hospital environment. Little is known about the prevalence and strain variability of C. difficile environmental contamination in health care facilities. The objective of this study was to assess C. difficile environmental contamination at various health care facilities in a metropolitan area and determine if the North American pulsed field gel electrophoresis type 1 (NAP1) strain was present.

METHODS

A cross-sectional pilot survey was conducted. Forty-eight environmental samples were collected from six health care facilities. Samples were cultured for the presence of C. difficile, and positive samples underwent pulsed field gel electrophoresis, toxinotyping, and detection of binary toxin and/or tcdC deletion.

RESULTS

C. difficile was cultured from 13 of 48 (27%) samples. Rooms housing a patient with C. difficile-associated disease (CDAD) were more likely to be culture positive than non-CDAD patient rooms (100% vs. 33%; P < 0.01); C. difficile was not isolated outside of patient rooms (0 of 12 samples). The NAP1 epidemic strain was found in 5 out of 6 facilities.

CONCLUSION

C. difficile spores frequently contaminated the hospital environment. Rooms with a CDAD patient were more likely to be contaminated than rooms without a CDAD patient. The NAP1 strain was prevalent throughout the metropolitan area.

Emergence of Clostridium difficile-associated disease in North America and Europe

The clinical spectrum of Clostridium difficile-associated disease (CDAD) ranges from diarrhoea to severe life-threatening pseudomembranous colitis. Although not always associated with previous antibiotic exposure, it is in the majority of cases. CDAD is recognised increasingly in a variety of animal species and in individuals previously not considered to be predisposed. C. difficile can be transmitted via personal contact or environmentally. The role of patients and healthcare workers who are symptom-free but colonised with C. difficile in the intestinal tract is unclear. C. difficile, with more than 150 PCR ribotypes and 24 toxinotypes, has a pathogenicity locus (PaLoc) with genes encoding enterotoxin A (tcdA) and cytotoxin B (tcdB). Genes for the binary toxin are located outside the PaLoc, but the role of this toxin is unclear. The recently completed genome sequence of C. difficile 630 revealed a large proportion of 11% of mobile genetic elements, mainly in the form of conjugative transposons. Diagnostic assays include tests for the detection of C. difficile products or genes and culture methods for isolation of a toxin-producing bacterium. Enzyme immunoassays to detect toxin in faeces are widely available, with varying sensitivities and specificities. Despite practical drawbacks and sensitivity less than 100%, the cell cytototoxicity assay is still considered to be the standard. Rapid diagnostic assays are available on a limited scale and require much improvement. Molecular tests enable the detection of carriers of toxigenic and non-toxigenic strains, as does culture. It is highly recommended to culture C. difficile from toxin-positive faeces samples and to store isolates for future characterisation and typing. The financial impact of CDAD on the healthcare system is substantial (5-15,000 euro/case in England and $1.1 billion/year in the USA). Assuming a European Union population of 457 million, the potential cost of CDAD can be estimated to be 3000 million euro/year, and is expected to almost double over the next four decades. In North America, increasing rates of CDAD have been reported in Canada and the USA since March 2003, involving a more severe course, higher mortality, increased risk of relapse and more complications. This increased virulence is presumably associated with higher levels of toxin production by fluoroquinolone-resistant strains belonging to PCR ribotype 027, pulsed-field gel electrophoresis (PFGE) type NAP1, REA (restriction endonuclease analysis) type BI and toxinotype III. In Europe, outbreaks of CDAD due to the new, highly virulent strain of C. difficile PCR ribotype 027, toxinotype III have been recognised in 75 hospitals in England, 16 hospitals in The Netherlands, 13 healthcare facilities in Belgium and nine healthcare facilities in France. These outbreaks are very difficult to control, and preliminary results from case-control studies indicate a correlation with fluoroquinolones and cephalosporins. Information concerning community-acquired cases of ribotype 027 is lacking, and data concerning its incidence in nursing homes are limited. European countries should first develop early-warning and response capabilities at a national level. Depending on the nature of the notifications received, countries should implement laboratory-based or patient-based surveillance systems in specific, targeted populations.

Implications of the changing face of Clostridium difficile disease for health care practitioners

Recent reported outbreaks of Clostridium difficile-associated disease in Canada have changed the profile of C difficile infections. Historically, C difficile disease was thought of mainly as a nosocomial disease associated with broad-spectrum antibiotics, and the disease was usually not life threatening. The emergence of an epidemic strain, BI/NAP1/027, which produces a binary toxin in addition to the 2 classic C difficile toxins A and B and is resistant to some fluoroquinolones, was associated with large numbers of cases with high rates of mortality. Recently, C difficile has been reported more frequently in nonhospital-based settings, such as community-acquired cases. The C difficile disease is also being reported in populations once considered of low risk (children and young healthy women). In addition, poor response to metronidazole treatment is increasing. Faced with an increasing incidence of C difficile infections and the changing profile of patients who become infected, this paper will reexamine the current concepts on the epidemiology and treatment of C difficile-associated disease, present new hypotheses for risk factors, examine the role of spores in the transmission of C difficile, and provide recommendations that may enhance infection control practices.

Evaluation of real-time PCR and conventional diagnostic methods for the detection of Clostridium difficile-associated diarrhoea in a prospective multicentre study

In this prospective multicentre study, an enzyme-linked fluorescent assay (VIDAS CDA2; bioMérieux), an enzyme-linked assay [Premier Toxins A and B (PTAB); Meridian] and an in-house real-time PCR amplifying the tcdB gene were compared with the cell cytotoxicity assay used as the ‘gold standard’ for diagnosis of Clostridium difficile-associated diarrhoea (CDAD). Faecal samples from patients with a request for C. difficile diagnosis and samples from patients with diarrhoea hospitalized for at least 72 h were collected for 3 consecutive months from four university medical centres in The Netherlands. In total, 547 faecal samples were obtained from 450 patients. Of 540 samples available for all of the assays, 84 (15.6 %) showed a positive result in one or more assays. The cell cytotoxicity assay was positive in 31 samples (5.7 %) from 28 patients. A diagnosis of CDAD was not considered by the physician in 5 (23.8 %) of 21 patients with CDAD who were hospitalized for at least 72 h. Compared with the cell cytotoxicity assay, the sensitivity of VIDAS, PTAB and PCR was 83.9, 96.8 and 87.1 %, respectively. The specificity of VIDAS, PTAB and PCR was 97.1, 94.3 and 96.5 %, respectively. The positive and negative predictive values for VIDAS, PTAB and PCR were 63.4 and 99.0 %, 50.9 and 99.8 %, and 60.0 and 99.2 %, respectively. Of 61 samples that were positive in one, two or three of the assays, 56 were available for discordance analysis. Discordance analysis was performed by culture of toxinogenic strains. The concordance of VIDAS, PTAB and PCR with culture was 53.6 % (30/56), 55.4 % (31/56) and 71.4 % (40/56), respectively. It was concluded that real-time PCR had the highest concordance with toxinogenic culture and is therefore the preferred method for diagnosing CDAD in faecal samples. It was also concluded that diagnosis of patients with diarrhoea who have been hospitalized for more than 72 h should focus mainly on the detection of C. difficile, irrespective of the physician's request.

Allen Denver Russell Memorial Lecture, 2006

Microbial pathogens continue as major threats to health. Indeed, many ongoing societal changes are enhancing our vulnerability and exposure to several frank and opportunistic pathogens. This, together with rampant antimicrobial resistance and reduced prospects for newer drugs and vaccines, is forcing a higher reliance on microbiocides in infection prevention and control. That this reliance may not be well-founded becomes apparent from a closer look at current ways of testing and registering microbiocides, their label claims as well as human and environmental safety of certain widely used microbicidal chemicals. Many methods to test microbiocides for registration are flawed and/or entail test conditions irrelevant to field use. Pathogens listed on product labels may not be among those amenable to interruption through microbiocide use. The wide variations and discrepancies in existing national/regional regulations for registering microbiocides for sale stifle innovation. This is a critical look at the above-mentioned issues with emphasis on chemicals meant for use on environmental surfaces and medical devices. It highlights better ways to test microbiocides and to attain global harmonization of testing and product registration. It also details the known and potential dangers of microbiocide use and what to consider in choosing such formulations for optimal safety and effectiveness. End users are advised to be more critical and prudent in the selection and application of microbicidal chemicals, manufacturers are encouraged to explore infection control products and technologies that are safer in the workplace and for the environment, and regulators are urged to review and update the requirements and procedures for premarket review of microbiocide efficacy data and label claims. Independent investigations are also urgently needed to document the proportion of nosocomial infections that would be amenable to prevention through chemical disinfection of environmental surfaces.

How long do nosocomial pathogens persist on inanimate surfaces? A systematic review

BACKGROUND

Inanimate surfaces have often been described as the source for outbreaks of nosocomial infections. The aim of this review is to summarize data on the persistence of different nosocomial pathogens on inanimate surfaces.

METHODS

The literature was systematically reviewed in MedLine without language restrictions. In addition, cited articles in a report were assessed and standard textbooks on the topic were reviewed. All reports with experimental evidence on the duration of persistence of a nosocomial pathogen on any type of surface were included.

RESULTS

Most gram-positive bacteria, such as Enterococcus spp. (including VRE), Staphylococcus aureus (including MRSA), or Streptococcus pyogenes, survive for months on dry surfaces. Many gram-negative species, such as Acinetobacter spp., Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Serratia marcescens, or Shigella spp., can also survive for months. A few others, such as Bordetella pertussis, Haemophilus influenzae, Proteus vulgaris, or Vibrio cholerae, however, persist only for days. Mycobacteria, including Mycobacterium tuberculosis, and spore-forming bacteria, including Clostridium difficile, can also survive for months on surfaces. Candida albicans as the most important nosocomial fungal pathogen can survive up to 4 months on surfaces. Persistence of other yeasts, such as Torulopsis glabrata, was described to be similar (5 months) or shorter (Candida parapsilosis, 14 days). Most viruses from the respiratory tract, such as corona, coxsackie, influenza, SARS or rhino virus, can persist on surfaces for a few days. Viruses from the gastrointestinal tract, such as astrovirus, HAV, polio- or rota virus, persist for approximately 2 months. Blood-borne viruses, such as HBV or HIV, can persist for more than one week. Herpes viruses, such as CMV or HSV type 1 and 2, have been shown to persist from only a few hours up to 7 days.

CONCLUSION

The most common nosocomial pathogens may well survive or persist on surfaces for months and can thereby be a continuous source of transmission if no regular preventive surface disinfection is performed.

A staff nurse's perspective of infection control problems

Earlier this month astonishing figures causing major concern were released from the Department of Health (DoH) showing the number of cases of Clostridium difficile in the over 65s in hospitals in England. This article focuses upon what is already known about infection control and concludes that a greater collaborative approach to infection control is needed, with a prudent use of broad spectrum antibiotics and a greater use of precautionary isolation measures based on patient symptoms, if infection rates are to fall.

Subtyping of Clostridium difficile PCR ribotype 001 by REP-PCR and PFGE

The REP-PCR (repetitive sequence-based PCR using repetitive extragenic palindromic primers) typing method and a modified PFGE method were applied to isolates of Clostridium difficile PCR ribotype 001 with the aim of comparing their performance as methods of subtyping this organism. Of 200 isolates from 60 hospitals tested by REP-PCR, eight subtypes were identified and labelled as REP-PCR subtypes 001-008. The predominant subtype, REP-PCR subtype 003, accounted for 47% of the total. Fifty-two of the 200 isolates were analysed by a modified PFGE method and seven subtypes were identified, labelled as PF-A-PF-G. There was excellent correlation between REP-PCR subtypes and PFGE subtypes with both methods displaying broadly similar discriminatory powers. However, REP-PCR subtyping proved to be a much easier, cheaper and more rapid method suitable for application for routine subtyping of C. difficile ribotype 001. Application of REP-PCR subtyping to UK isolates of C. difficile PCR ribotype 001 from 60 different centres revealed a wide distribution of REP-PCR subtype 003 throughout England and Wales, with a regional clustering of REP-PCR subtype 001 around Northwest England and North Wales. Analysis of isolates from a single hospital over a 4-year period revealed a change in predominant subtype over time.

The effect of Perasafe® and sodium dichloroisocyanurate (NaDCC) against spores of Clostridium difficile and Bacillus atrophaeus on stainless steel and polyvinyl chloride surfaces

Clostridium difficile is an important cause of nosocomial diarrhoea. The aim of this study was to evaluate the potential for Perasafe, a recently introduced biocide, to contribute to control of C. difficile spores in the patient environment, in comparison with the chlorine-releasing agent sodium dichloroisocyanurate (NaDCC). These agents were evaluated against a water control, in a surface test on stainless steel and polyvinyl chloride (PVC) floor covering, materials commonly found in the hospital environment. The organisms studied were a toxigenic clinical isolate of C. difficile, and Bacillus atrophaeus (formerly B. subtilis var niger). The data indicate that in our in vitro system, Perasafe was significantly more active than NaDCC (1000 ppm available chlorine) against C. difficile spores dried on stainless steel surfaces, and against B. atrophaeus on PVC floor covering material, achieving mean log10 reduction factors in viable counts of 6 and 5.5, respectively, at 10 min exposures. Perasafe appeared to be less lethal in 10 min exposures to C. difficile spores fixed on PVC floor covering material. In general, 1000 ppm chlorine generated from NaDCC showed lower log10 reduction factors in viable counts at 10 min, ranging from 0.7 to 1.5, than Perasafe which ranged from 2.7 to 6.0. The potential efficacy of Perasafe in reducing the density of C. difficile spores in the patient environment in hospitals, nursing homes or other long-stay facilities should be evaluated in field studies.

Comparison of the effect of detergent versus hypochlorite cleaning on environmental contamination and incidence of Clostridium difficile infection

To determine how best to decontaminate the hospital environment of Clostridium difficile, we carried out a cross-over study on two elderly medicine wards to determine whether cleaning with a hypochlorite disinfectant was better than using neutral detergent in reducing the incidence of C. difficile infection (CDI). We examined 1128 environmental samples in two years, 35% of which grew C. difficile. There was a significant decrease of CDI incidence on ward X, from 8.9 to 5.3 cases per 100 admissions (P<0.05) using hypochlorite, but there was no significant effect on ward Y. On ward X the incidence of CDI was significantly associated with the proportion of culture-positive environmental sites (P<0.05). On ward Y the only significant correlation between CDI and C. difficile culture-positive environmental sites was in patient side-rooms (r=0.41, P<0.05). The total daily defined doses of cefotaxime, cephradine and aminopenicillins were similar throughout the trial. These results provide some evidence that use of hypochlorite for environmental cleaning may significantly reduce incidence of CDI, but emphasize the potential for confounding factors.

Impact of changes in antibiotic policy on Clostridium difficile-associated diarrhoea (CDAD) over a five-year period in a district general hospital

The impact of changes in antibiotic policy on Clostridium difficile-associated diarrhoea (CDAD), over a five-year period between 1995 and 2000, were studied in the Preston Acute Hospitals Trust. In 1996 the policy was changed in the Preston Acute Hospitals Trust from cefotaxime to ceftriaxone for initial treatment of severe sepsis or pneumonia in medical patients. Over the next nine months the average number of patients with C. difficile toxin-positive stools per quarter increased from 16 to 39. The predicted use of ceftriaxone exceeded by 65% an estimate based on prior use of cefotaxime. A policy of restricted duration of ceftriaxone was introduced, and although this reduced usage by over 50%, CDAD continued at an average of 9.2 cases per month, despite withdrawal of oral cephalosporins in December 1998. In August 1999 levofloxacin was substituted for ceftriaxone in the policy. The incidence of CDAD fell progressively to five cases per month by 2000. It would appear that a short (typically three dose) course of third-generation cephalosporin poses a similar risk for CDAD as a more prolonged course. The six-month delay in the decline of CDAD after virtual withdrawal of cephalosporins may reflect a slowly diminishing environmental reservoir.

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 in long-term-care facilities for the elderly

Antimicrobial agents are among the most frequently prescribed medications in long-term-care facilities (LTCFs). Therefore, it is not surprising that Clostridium difficile colonization and C. difficile-associated diarrhea (CDAD) occur commonly in elderly LTCF residents. C. difficile has been identified as the most common cause of non-epidemic acute diarrheal illness in nursing homes, and outbreaks of CDAD in LTCFs have also been recognized. This position paper reviews the epidemiology and clinical features of CDAD in elderly residents of LTCFs and, using available evidence, provides recommendations for the management of C. difficile in this setting.

Clostridium difficile

Clostridium difficile is the most commonly identified infective cause of antibiotic associated diarrhoea. Broad spectrum antibiotics, are most frequently incriminated, although short (<3 day) antibiotic courses cause fewer episodes. Gold standard cell-culture based cytotoxin assays have been compared to rapid immunoassays, which are less effective, especially since toxin A negative, toxin B positive strains have been shown to be truly virulent. Details of colonization and adherence mechanisms have been revealed, and clonal spread has been demonstrated. The mainstay of treatment of C. difficile infection remains metronidazole. Justified fears over resistance are leading to development of alternative therapeutic strategies. These include a toxin binding polymer and ongoing biotherapy research. An antibody rise to toxin A during an episode of C. difficile diarrhoea protects against recurrence, and trials are in progress to investigate immunization: a toxoid vaccine which is immunogenic and safe in healthy volunteers shows promise for the future.