Outbreak Of Clostridium Difficile Infection Research Articles

Control of an outbreak of diarrhoea in a vascular surgery unit caused by a high-level clindamycin-resistant Clostridium difficile PCR ribotype 106

This report describes an outbreak of Clostridium difficile infection (CDI) in a vascular surgery ward in 2009 caused by a high-level clindamycin-resistant ribotype 106. A case of CDI was defined as a patient with diarrhoea, positive for C.difficile toxin and negative for other enteric pathogens. Cultures were sent to the Scottish Salmonella Shigella and Clostridium difficile Reference Laboratory (SSSCDRL) for PCR ribotyping, antibiotic susceptibility testing and PCR detection of ermB. The mean age of the nine patients was 73 years (range: 38-90 years). All had received clindamycin and ciprofloxacin. All cases were typed as PCR ribotype 106 and they showed high-level resistance to clindamycin. Five of these isolates were tested by PCR for the presence of the ermB gene and no amplification was detected. This strain has rarely been isolated from patients on this ward. The outbreak was controlled successfully by closure of the ward with terminal cleaning, reinforcement of infection control precautions and the introduction of a new antibiotic policy. It is notable that this outbreak was caused by a strain with high-level clindamycin resistance not mediated by ermB. It also re-emphasizes that outbreaks of CDI can be caused by C.difficile PCR ribotypes other than 027. The outbreak was most likely associated with the use of clindamycin and ciprofloxacin cross-infection with spores in this environment. Implementation of strict infection control precautions, antimicrobial stewardship and enhanced environmental cleaning are key components in managing such an outbreak successfully. The number of meticillin-resistant Staphylococcus aureus acquisitions also fell substantially after these interventions.

Emergence of Clostridium difficile Ribotype 027 in Korea

BackgroundClostridium difficile infection (CDI) has markedly risen and is associated with hypervirulent ribotype 027 outbreaks in North America and Europe since 2003. The aims of this study were to determine the prevalence of ribotype 027 among C. difficile isolates in Korea, to characterize the ribotype 027 isolates, and to determine the clinical severity of CDI in patients infected with these isolates.MethodsA total of 1,251 isolates of C. difficile recovered from stool specimens of suspected CDI patients at two tertiary-care hospitals and one commercial laboratory between 2002 and 2009. Genes for toxin A (tcdA), toxin B (tcdB), and binary toxin (cdtA and cdtB) were detected by PCR. Mutation in the tcdC gene was detected by sequencing after PCR amplification. For molecular genotyping, we performed PCR-ribotyping, pulsed-field gel electrophoresis (PFGE), and multilocus variable-number tandem-repeat analysis (MLVA). Minimum inhibitory concentrations of moxifloxacin were determined using Etest strips (AB bioMérieux, Sweden).ResultsWe identified 7 isolates as ribotype 027. These isolates had the same tcdC mutation as the epidemic strain, and 6 of them were resistant to moxifloxacin. The isolates were categorized into 3 different PFGE types and 7 different MLVA types. All the 7 cases had occurred sporadically.ConclusionsC. difficile ribotype 027 is uncommon, but it has emerged in Korea. The spread of this ribotype should be closely monitored in order to avoid an outbreak of CDI in Korea.

Epidemiological Model forClostridium difficileTransmission in Healthcare Settings

Recent outbreaks of Clostridium difficile infection (CDI) have been difficult to control, and data indicate that the importance of different sources of transmission may have changed. Our objectives were to evaluate the contributions of asymptomatic and symptomatic C. difficile carriers to new colonizations and to determine the most important epidemiological factors influencing C. difficile transmission. Retrospective cohort study of all patients admitted to medical wards at a large tertiary care hospital in the United States in the calendar year 2008. Data from six medical wards and published literature were used to develop a compartmental model of C. difficile transmission. Patients could be in one of five transition states in the model: resistant to colonization (R), susceptible to colonization (S), asymptomatically colonized without protection against CDI (C(-)), asymptomatically colonized with protection against CDI (C(+)), and diseased (ie, with CDI; D). The contributions of C(-), C(+), and D patients to new colonizations were similar. The simulated basic reproduction number ranged from 0.55 to 1.99, with a median of 1.04. These values suggest that transmission within the ward alone from patients with CDI cannot sustain new C. difficile colonizations and therefore that the admission of colonized patients plays an important role in sustaining transmission in the ward. The epidemiological parameters that ranked as the most influential were the proportion of admitted C(-) patients and the transmission coefficient for asymptomatic carriers. Our study underscores the need to further evaluate the role of asymptomatically colonized patients in C. difficile transmission in healthcare settings.

Evaluation of Patient Sharing and the Use of Standardized Case Definitions to Describe a Clostridium difficile Infection Outbreak

Evaluation of Patient Sharing and the Use of Standardized Case Definitions to Describe a Clostridium difficile Infection Outbreak

Point-Counterpoint: What Is the Current Role of Algorithmic Approaches for Diagnosis of Clostridium difficile Infection?

ABSTRACT With the recognition of several serious outbreaks of Clostridium difficile infection in the industrialized world coupled with the development of new testing technologies for detection of this organism, there has been renewed interest in the laboratory diagnosis of C. difficile infection. Two factors seem to have driven much of this interest. First, the recognition that immunoassays for detection of C. difficile toxins A and B, for many years the most widely used tests for C. difficile infection diagnosis, were perhaps not as sensitive as previously believed at a time when attributed deaths to C. difficile infections were showing a remarkable rise. Second, the availability of FDA-approved commercial and laboratory-developed PCR assays which could detect toxigenic strains of C. difficile provided a novel and promising testing approach for diagnosing this infection. In this point-counterpoint on the laboratory diagnosis of C. difficile infection, we have asked two experts in C. difficile infection diagnosis, Ferric Fang, who has recently published two articles in the Journal of Clinical Microbiology advocating the use of PCR as a standalone test (see this author's references 12 and 28), and Mark Wilcox, who played a key role in developing the IDSA/SHEA guidelines on Clostridium difficile infection (see Wilcox and Planche's reference 1), along with his colleague, Tim Planche, to address the following question: what is the current role of algorithmic approaches to the diagnosis of C. difficile infection?

Lack of Increased Colonization with Vancomycin-Resistant Enterococci during Preferential Use of Vancomycin for Treatment during an Outbreak of Healthcare-Associated Clostridium difficile Infection

To assess whether use of oral vancomycin for treatment during an outbreak of Clostridium difficile infection (CDI) was associated with increased rates of colonization with vancomycin-resistant enterococci (VRE). A retrospective analysis of hospital databases. The Jewish General Hospital in Montreal, Quebec, Canada. We collected data regarding VRE colonization and CDI from November 1, 2000, through September 30, 2007, during which policies of preferential oral metronidazole or vancomycin treatment were implemented to control an outbreak of CDI. Four periods were considered: period 1, the preoutbreak period when metronidazole was used; period 2, the CDI outbreak period when metronidazole was used; period 3, the postoutbreak period when vancomycin was used; and period 4, the postoutbreak period when metronidazole was used. A total of 2,412 cases of CDI and 425 cases of VRE colonization were identified. The rate of CDI increased significantly during period 2 and decreased to preoutbreak levels during period 3. The rate of VRE also increased during period 2 and decreased during the first 18 months of period 3. A clonal outbreak of cases of VRE (VanA) colonization was observed toward the end of period 3 and into period 4. Excluding the period of the clonal outbreak, there was a strong correlation between the number of cases of CDI and VRE colonization (r=0.736; P=.001) and a negative association between VRE colonization and vancomycin use (r=-0.765; P=.04). Increased vancomycin use was not associated with an increase in VRE colonization over a 2-year period. Restriction of vancomycin use during CDI outbreaks because of the fear of increasing VRE colonization may not be warranted.

Investigation of a large outbreak of Clostridium difficile PCR-ribotype 027 infections in northern France, 2006-2007 and associated clusters in 2008-2009

In 2006 and 2007, a large outbreak of Clostridium difficile infections (CDIs) with PCR-ribotype 027 was identified in northern France. Overall, 38 healthcare facilities notified 529 CDIs over a 22-month period, including 281 laboratory-confirmed CDI 027 and 248 non-confirmed CDI 027 cases (incidence rate per 10,000 elective bed days: 1.63, range: 0.07 to 7.94). The cases occurred mainly in long-term care hospital facilities and nursing homes, near the border between France and Belgium. An active surveillance and prevention campaign was launched at the first epidemic peak including hygiene precautions for healthcare professionals, which supported healthcare facilities to improve care organisation. The outbreak was controlled at the end of 2007, but sporadic cases were identified until the end of 2009. A bundle of appropriate control measures may halt the spread of such outbreaks, provided that substantial human resources and financial support are available.

Fidaxomicin (OPT-80) for the treatment of Clostridium difficile infection

Importance of the field: Clostridium difficile infection (CDI) has become an increasingly important healthcare-associated complication in many countries. CDI outbreaks, a new ‘hypervirulent’ form and increased worldwide rates have underscored four urgent unmet needs for this disease: i) effective prevention of CDI; ii) therapies to produce faster resolution of CDI symptoms; iii) therapies to treat severe CDI more effectively and reduce its mortality; and iv) therapies to reduce the CDI recurrence rate following treatment.Areas covered in this review: Fidaxomicin, a new macrocyclic antibiotic, has demonstrated potent in vitro activity against C. difficile with limited or no activity against normal fecal flora. It is minimally absorbed from the intestinal tract, even in the presence of intestinal inflammation. When tested against oral vancomycin in clinical studies of CDI therapy, it has equivalent efficacy for curing CDI at end of treatment and a comparable safety profile to that agent. However, fidaxomicin therapy of CDI is associated with significantly fewer CDI recurrences in the 28 days following treatment. Symptom resolution is also slightly quicker in some CDI patients. Additional fecal flora analysis in the CDI trials showed that fewer individuals developed intestinal colonization with vancomycin-resistant enterococci (VRE) among the fidaxomicin-treated group. This new molecule, which has just completed two large Phase III multicenter studies, successfully addresses two of the four urgent and unmet needs for dealing with CDI.What the reader will gain: Fidaxomicin is as effective and as safe as vancomycin therapy for treating CDI but is associated with far fewer recurrences post-treatment and a decreased risk of VRE acquisition.Take home message: Fidaxomicin is a potential new therapy for CDI which has the capacity to substantially decrease post-treatment recurrences and is as safe and well-tolerated as standard vancomycin treatment.

Analysis of an outbreak of Clostridium difficile infection controlled with enhanced infection control measures

Analysis of an outbreak of Clostridium difficile infection controlled with enhanced infection control measures

Clostridium difficile Strain NAP-1 Is Not Associated With Severe Disease in a Nonepidemic Setting

Recent outbreaks of Clostridium difficile infection (CDI) in North America and in Europe with very high case-fatality rates have been associated with infection by North American Pulsed Field Type I (NAP-1) isolates. This study examined whether NAP-1 strains are associated with worse outcomes of CDI in a nonepidemic, nosocomial setting. All cases of CDI that occurred over a 13-month period at a tertiary medical center were examined for risk factors associated with increased severity of CDI and other outcomes. Stool samples from each patient were cultured for C difficile and the resulting isolates were strain-typed by pulsed-field gel electrophoresis. Strain types were obtained from 236 of 272 CDI samples; the NAP-1 strain was identified in 59 (25%). In this inpatient cohort of patients with CDI, the incidence of in hospital death was 12.1% and of death caused by CDI was 4.0%. Of the patients with CDI, 22.1% met the combined outcome end point of severe CDI. In both univariate and multivariate analyses, patients infected with the NAP-1 strain did not have worse outcomes compared with those infected with non-NAP-1 strains. Infection with the NAP-1 strain was correlated with admission from outside health care facilities regardless of whether symptoms of CDI began before or after admission to the study hospital. The NAP-1 strain of C difficile was found to cause 25% of cases of CDI in the hospital where the study was performed. However, compared with non-NAP-1 strains, CDI was not associated with increased severity of disease in this nonepidemic setting.

Successful combat of an outbreak due to Clostridium difficile PCR ribotype 027 and recognition of specific risk factors

In the period April–September 2005, an outbreak of Clostridium difficile infection (CDI) due to PCR ribotype 027 occurred among 50 patients in a 341-bed community hospital in Harderwijk, The Netherlands. A retrospective case–control study was performed to identify risk factors specific for CDI, using a group of patients with CDI (n = 45), a group of randomly selected control patients without diarrhoea (n = 90), and a group of patients with non-infectious diarrhoea (n = 109). Risk factors for CDI and for non-CDI diarrhoea were identified using multiple logistic regression analysis. Independent risk factors for CDI were: age above 65 years (OR 2.6; 95% CI 1.0–5.7), duration of hospitalization (OR 1.04 per additional day; 95% CI 1.0–1.1), and antibiotic use (OR 12.5; 95% CI 3.2–48.1). Of the antibiotics used, cephalosporins and fluoroquinolones were identified as the major risk factors for development of CDI. The risk of developing CDI was particularly high in people receiving a combination of a cephalosporin and a fluoroquinolone (OR 57.5; 95% CI 6.8–483.6). The main factors affecting the risk of non-CDI diarrhoea were proton-pump inhibitors, immunosuppressive drugs, underlying digestive system disease, previous surgery, and gastric tube feeding. The outbreak ended only after implementation of restricted use of cephalosporins and a complete ban on fluoroquinolones, in addition to general hygienic measures, cohorting of patients in a separate ward, education of staff, and intensified environmental cleaning. The results of this study support the importance of appropriate antimicrobial stewardship in the control of hospital outbreaks with C. difficile PCR ribotype 027.

National point prevalence of Clostridium difficile in US health care facility inpatients, 2008

Recent published estimates of Clostridium difficile infection (CDI) incidence have been based on small numbers of hospitals or national hospital discharge data. These data suggest that CDI incidence is increasing. We conducted a point prevalence survey of C difficile in inpatients at US health care facilities. The survey was developed, received Institutional Review Board approval, and was then distributed to all Association for Professionals in Infection Control and Epidemiology, Inc (APIC) members. They were asked to complete the survey on 1 day between May 7 and August 29, 2008, reporting the number of inpatients with CDI or colonization and facility-specific information. Personnel at 648 hospitals completed the survey; this represents approximately 12.5% of all US acute care facilities. All but 3 states and the District of Columbia were represented (mean, 14 facilities per state; range, 2-43). Eighty-two percent reported that their CDI rate had not decreased in the past 3 years. Respondents reported 1443 C difficile-colonized/infected patients among 110,550 inpatients; the overall C difficile prevalence rate was 13.1 per 1000 inpatients (94.4% infection). Detailed data were provided on 1062 (73.6%) patients. Of these, 55.5% were female, 69.2% were >60 years of age, 67.6% had selected comorbid conditions, 79% had received antimicrobials within 30 days, and 94.4% were detected by enzyme immunoassay. The majority of patients (54.4%) were diagnosed < or =48 hours of hospitalization, but 35% had been admitted to a long-term care facility within 30 days, and 47% had been hospitalized within 90 days; 73% met Centers for Disease Control and Prevention criteria for health care-associated CDI. Most facilities (>90%) used contact isolation for CDI patients. Bleach was used for environmental disinfection more commonly during CDI outbreaks than during nonoutbreak periods. Our survey documents a higher C difficile prevalence rate than previous estimates using different methodologies. The majority of inpatient CDI appears to be health care associated. Given that not all patients with diarrhea are tested for CDI and that most facilities use enzyme immunoassays with limited sensitivity to detect C difficile, these are minimum estimates of the US health care facility C difficile burden.

Analysis of an outbreak of Clostridium difficile infection controlled with enhanced infection control measures

In October 2004, our Clostridium difficile infection (CDI) rate increased (relative risk, 3.51; 95% confidence interval: 2.96-4.16) from a baseline rate of 1.35 per 1000 patient-days. We describe the outbreak, the relationship between antibiotic use and CDI, and the effect of enhanced infection control measures (EICM) on CDI. Rates were calculated as positive C difficile toxin A or B tests among patients with nosocomial diarrhea per 1000 patient-days (duplicates removed). Antibiotic use was calculated as defined daily dose per 1000 patient-days. EICM consisted of (1) placing patients with diarrhea into empiric Contact Precautions, (2) cleaning with a bleach product in areas with CDI patients, and (3) requiring soap and water hand hygiene when caring for CDI patients. CDI rates were analyzed by chi(2) for trend. Time series methodology was used to examine the association between CDI and antibiotic use. During the outbreak (October 2004-May 2005), we observed 144 excess cases of CDI. The CDI rate decreased after EICM were implemented (P < .0001) and has been maintained for 36 months beyond the outbreak. Multivariate analysis revealed positive associations between CDI rates and cefazolin use (P = .008) and levofloxacin/gatifloxacin use (P = .015). Despite an association between some antibiotic use and CDI rates, we achieved sustained control of an outbreak using EICM without formulary changes or new antibiotic control policies. This suggests that patient-to-patient spread may be a more important cause of increased CDI rates.

What is on that keyboard? Detecting hidden environmental reservoirs of Clostridium difficile during an outbreak associated with North American pulsed-field gel electrophoresis type 1 strains

Numerous studies have demonstrated that environmental surfaces in the rooms of patients with Clostridium difficile infection (CDI) are often contaminated with spores. However, less information is available regarding the frequency of contamination of environmental surfaces outside of CDI isolation rooms. We performed a point-prevalence culture survey for C difficile in rooms of patients not in isolation for CDI, in physician and nurse work areas, and on portable equipment, including pulse oximetry devices, electrocardiogram machines, mobile computers, and medication distribution carts. Isolates were characterized by assessment of toxin production, polymerase chain reaction (PCR) ribotyping, and PCR for binary toxin genes. Of 105 nonisolation rooms, 17 (16%) were contaminated with toxin-producing C difficile, with the highest rate of contamination on the spinal cord injury unit (32%). Of 87 surfaces cultured outside of patient rooms, 20 (23%) were contaminated, including 9 of 29 (31%) in physician work areas, 1 of 10 (10%) in nurse work areas, and 9 of 43 (21%) portable pieces of equipment, including a pulse oximetry finger probe, medication carts, and bar code scanners on medication carts. Of 26 isolates subjected to typing, 19 (73%) matched ribotype patterns detected in stool samples from CDI patients and 13 (50%) were epidemic, binary toxin-positive strains. In the context of a CDI outbreak, we found that environmental contamination was common in nonisolation rooms, in physician and nurse work areas, and on portable equipment. Further research is needed to determine whether contamination in these areas plays a significant role in transmission.

Treatment ofClostridium difficileInfection

Recent outbreaks of Clostridium difficile infection (CDI) in North America have been due to a more virulent, possibly more resistant strain that causes more-severe disease, making prompt recognition of cases and optimal management of infection essential for a successful therapeutic outcome. Treatment algorithms are presented to help guide the management of patients with CDI. Metronidazole has been recommended as initial therapy since the late 1990s and continues to be the first choice for all but seriously ill patients and those with complicated or fulminant infections or multiple recurrences of CDI, for whom vancomycin is recommended. Other options for recurrent CDI, such as probiotics and currently available anion-exchange resins, have limited efficacy and are potentially harmful. Intravenous immunoglobulin may benefit patients with refractory, recurrent, or severe disease, but no controlled data are available. Two antimicrobials available in the United States for other indications, nitazoxanide and rifaximin, have been used successfully for CDI treatment but, like metronidazole, lack United States Food and Drug Administration approval for this indication. Experimental treatments currently in clinical development include a toxin-binding polymer, tolevamer; 2 poorly absorbed antimicrobials, OPT-80 (formerly known as Difimicin) and ramoplanin; monoclonal antibodies; and a C. difficile vaccine.

Measures to Control and PreventClostridium difficileInfection

Control of Clostridium difficile infection (CDI) outbreaks in health care facilities presents significant challenges to infection control specialists and other health care workers. C. difficile spores survive routine environmental cleaning with detergents and hand hygiene with alcohol-based gels. Enhanced cleaning of all potentially contaminated surfaces with 10% sodium hypochlorite reduces the environmental burden of C. difficile, and use of barrier precautions reduces C. difficile transmission. Thorough handwashing with chlorhexidine or with soap and water has been shown to be effective in removing C. difficile spores from hands. Achieving high-level compliance with these measures is a major challenge for infection control programs. Good antimicrobial stewardship complements infection control efforts and environmental interventions to provide a comprehensive strategy to prevent and control outbreaks of CDI. The efficacy of metronidazole or vancomycin prophylaxis to prevent CDI in patients who are receiving other antimicrobials is unproven, and treatment with these agents is ineffective against C. difficile in asymptomatic carriers.

Control of an Outbreak of Infection with the Hypervirulent Clostridium difficile BI Strain in a University Hospital Using a Comprehensive "Bundle" Approach

In June 2000, the hospital-acquired Clostridium difficile (CD) infection rate in our hospital (University of Pittsburgh Medical Center-Presbyterian, Pittsburgh, PA) increased to 10.4 infections per 1000 hospital discharges (HDs); the annual rate increased from 2.7 infections per 1000 HDs to 7.2 infections per 1000 HDs and was accompanied by an increase in the frequency of severe outcomes. Forty-seven (51%) of 92 HA CD isolates in 2001 were identified as the "epidemic BI strain." A comprehensive CD infection control "bundle" was implemented to control the outbreak of CD infection. The CD infection control bundle consisted of education, increased and early case finding, expanded infection-control measures, development of a CD infection management team, and antimicrobial management. Process measures, antimicrobial usage, and hospital-acquired CD infection rates were analyzed, and CD isolates were typed. The rates of compliance with hand hygiene and isolation were 75% and 68%, respectively. The CD management team evaluated a mean of 31 patients per month (11% were evaluated for moderate or severe disease). Use of antimicrobial therapy associated with increased CD infection risk decreased by 41% during the period 2003-2005 (P<.001). The aggregate rate of CD infection during the period 2001-2006 decreased to 4.8 infections per 1000 HDs (odds ratio, 2.2; 95% confidence interval, 1.4-3.1; P<.001) and by 2006, was 3.0 infections per 1000 HDs, a rate reduction of 71% (odds ratio, 3.5; 95% confidence interval, 2.3-5.4; P<.001). During the period 2000-2001, the proportion of severe CD cases peaked at 9.4% (37 of 393 CD infections were severe); the rate decreased to 3.1% in 2002 and further decreased to 1.0% in 2006--a 78% overall reduction (odds ratio, 20.3; 95% confidence interval, 2.8-148.2; P<.001). In 2005, 13% of CD isolates were type BI (20% were hospital acquired), which represented a significant reduction from 2001 (P<.001). The outbreak of CD infection with the BI strain in our hospital was controlled after implementing a CD infection control "bundle." Early identification, coupled with appropriate control measures, reduces the rate of CD infection and the frequency of adverse events.

An Outbreak of Severe Clostridium difficile–Associated Disease Possibly Related to Inappropriate Antimicrobial Therapy for Community-Acquired Pneumonia

We report a severe outbreak of Clostridium difficile infection. According to a chart review, half of the patients who received treatment for bacterial pneumonia before they developed C. difficile infection may not have had pneumonia. Excessive use of the hospital's new pneumonia care plan during the influenza season may have contributed to the intensity of this outbreak.

Use of pulsed-field gel electrophoresis for investigation of an outbreak of Clostridium difficile infection among geriatric patients.

A six-month outbreak of Clostridium difficile infection among elderly residents of a middle-term-care facility was investigated. Pulsed-field gel electrophoresis was used to genotype 22 outbreak strains and 30 epidemiologically unrelated strains. A prospective case-control study was conducted to identify risk factors for epidemic Clostridium difficile-associated diarrhea. All epidemiologically unrelated Clostridium difficile strains of the same serogroup could be differentiated by their DNA patterns with two restriction enzymes (SmaI and KspI). Among clustered strains, two epidemic serogroups (C and K) were identified. Two different DNA patterns were identified among serogroup C strains and three among serogroup K strains. Multivariate analysis showed that the risk of Clostridium difficile infection increased with antimicrobial chemotherapy (beta-lactam agents and pristinamycin) and the presence of a feeding tube. This study confirms the high discriminative power of restriction fragment length polymorphism analysis by pulsed-field gel electrophoresis to describe Clostridium difficile epidemiology. The typing results confirm that infection was principally exogenous in this outbreak. Furthermore, they indicate the need to improve all measures limiting transmission of infection.

Correlation of pyrolysis mass spectrometry and outer membrane protein profiles of Clostridium difficile.

To perform pyrolysis mass spectrometry (PyMS), a small sample of colony material is thermally degraded in a vacuum, thus yielding mixed volatile products whose composition reflects that of the organism. Mass spectrometric analysis of the products yields spectra that can be compared statistically; consequently, fine differences in cell composition can be detected [1]. Typing by PyMS is rapid, inexpensive, automated, and non-species-specific and has a high throughput (100-150 isolates per day) [2]. It has been used successfully to type isolates recovered during nosocomial outbreaks of Clostridium difficile infection [3] and now is a routine typing method for this organism in the United Kingdom. However, PyMS is a fingerprinting method; no permanent type designation has been assigned, and variations between different analytical batches prevent interbatch comparisons of spectra. This difficulty in routine typing of C. difficile is overcome by including representative isolates from any outbreak with further batches of isolates recovered in the same hospital. Our aim, for two reasons, was to develop the capability to predict C. difficile serotypes based on the scheme of Delmee et al. [4] from PyMS data. First, these serotypes correlate well with pathogenicity; isolates of groups G and H are commonly associated with nosocomial outbreaks, and serogroup F strains do not produce toxin A [5]. Furthermore, the results of outer membrane protein (OMP) profiles [6] and SDS-PAGE analysis of whole-cell protein [7] correlated well for these serogroups, thus indicating an underlying subdivision of the species that affects many of their properties. Second, assignment of a predicted serotype would, in effect, produce a permanent type designation for isolates. Nosocomial outbreaks of cross-infection due to most organisms tend to be of limited duration and scope, and the advantages of permanent type designations in these outbreaks are minimal. However, those investigators involved in the analysis of community outbreaks rightly criticize fingerprinting methods for their inability to assign the permanent type designations that are required for much broader temporal and geographic surveillance. Although permanent type designations