Prevalence surveys of healthcare-associated infections: what do they tell us, if anything?

Inverse probability weighting leads to more accurate incidence estimates for healthcare-associated infections in intensive care units - results from two national surveillance systems

BACKGROUND

Two main approaches are employed to monitor healthcare-associated infections (HAIs): longitudinal surveillance, which allows the measurement of incidence rates, and point prevalence surveys (PPSs). PPSs are less time-consuming; however, they are affected by length-biased sampling, which can be corrected through inverse probability weighting. We assessed the accuracy of this method by analysing data from two Italian national surveillance systems.

METHODS

Ventilator-associated pneumonia (VAP) and central-line-associated bloodstream infection (CLABSI) incidence measured through a prospective surveillance system (GiViTI) was compared with incidence estimates obtained through conversion of crude and inverse probability weighted prevalence of the same HAIs in intensive care units (ICUs) measured through a PPS. Weighted prevalence rates were obtained after weighting all patients inversely proportional to their time-at-risk. Prevalence rates were converted into incidence per 100 admissions using an adapted version of the Rhame and Sudderth formula.

FINDINGS

Overall, 30,988 patients monitored through GiViTI, and 1435 patients monitored through the PPS were included. A significant difference was found between incidence rates estimated based on crude VAP and CLABSI prevalence and measured through GiViTI (relative risk 2.5 and 3.36; 95% confidence interval 1.42-4.39 and 1.33-8.53, P=0.006 and 0.05, respectively). Conversely, no significant difference was found between incidence rates estimated based on weighted VAP and CLABSI prevalence and measured through GiViTI (P=0.927 and 0.503, respectively).

CONCLUSIONS

When prospective surveillance is not feasible, our simple method could be useful to obtain more accurate incidence rates from PPS data.

Healthcare-associated infections in long-term care facilities: a systematic review and meta-analysis of point prevalence studies

Objectives

Residents of long-term care facilities (LTCFs) are especially vulnerable to acquiring healthcare-associated infections (HAIs). Our systematic review and meta-analysis estimated the burden of HAIs, identified the most frequent HAIs and explored the impact of facility-level and surveillance methodological differences on HAI burden in LTCFs, as determined by point prevalence studies (PPS).

Design

Systematic review and meta-analysis.

Data sources

Bibliographic databases MEDLINE (Ovid), Embase (Ovid) and CINAHL (EBSCOhost) were searched for potentially eligible English-language original research publications. References of short-listed full-text publications, the European Centre for Disease Control and Prevention website and an unpublished 2016-2022 Australian Aged Care PPS report were also checked.

Eligibility criteria

PPS monitoring HAIs, published and undertaken between January 1991 and June 2023 in LTCFs.

Data extraction and synthesis

Two reviewers independently screened for eligible PPS and if included, assessed risk of bias for each PPS using the Joanna Briggs Institute (JBI) critical appraisal tool for prevalence studies. Meta-analysis was performed using a generalised linear mixed model.

Results

31 publications (including 123 PPS from 33 countries encompassing 709 860 residents) were included. Nine PPS (7.3%) were allocated a JBI quality score greater than 80% while 30 PPS (24.4%) were allocated a score between 70% and 80%. The overall pooled HAI point prevalence was 3.5% (95% CI 3.1% to 4.0%); 3.9% (95% CI 3.2% to 4.7%) when higher bias-risk PPS (<70% quality score) were excluded. Of 120 PPS, the most frequently reported HAIs were urinary tract (UTIs; 38.9%), respiratory tract (RTIs; 33.6%) and skin or soft tissue (SSTIs; 23.7%) infections. HAI point prevalence varied by geographical region (p<0.001), study decade (p<0.001) and HAI surveillance definitions used (p<0.001). There was no difference across facility types (p=0.57) or season (p=0.46).

Conclusions

HAIs remain a global public health problem and threat to the safety of LTCF residents; effective infection prevention and control strategies to reduce HAIs in LTCFs are still required. Guidance specifically about the prevention and management of UTIs, RTIs and SSTIs should be prioritised.

PROSPERO registration number

CRD42023406844.

Intermittent point prevalence surveys on healthcare-associated infections, 2011 and 2016, in England: what are the surveillance and intervention priorities?

BACKGROUND

Point prevalence surveys are an important surveillance method for determining the burden of healthcare-associated infections (HCAIs).

AIM

To outline the key results of two point prevalence surveys in England (2011 and 2016).

METHODS

All National Health Service and independent sector hospitals in England were eligible to participate. Data were collected between September and November in both 2011 and 2016 based on the protocol and codebook devised by the European Centre for Disease Prevention and Control. Analysis was performed using Stata Version 13 and SAS Version 9.3. A mixed-effects model was applied, which allowed estimation of organization-specific means and accounted for the heterogeneity in the responses from different organizations.

FINDINGS

A total of 100,755 case records were included (52,433 in 2011 and 48,312 in 2016). The estimated prevalence of HCAIs was slightly higher in 2016 [6.89%, 95% confidence interval (CI) 6.21-7.57%] than in 2011 (6.41%, 95% CI 5.75-7.06%). In both surveys, the prevalence of HCAIs was highest in adult intensive care units (23.1% in 2011, 21.2% in 2016), and pneumonia/lower respiratory tract infections was the most common cause of HCAIs (22.7% in 2011 vs 29.2% in 2016). Inpatients in acute hospitals were older and had higher risk of dying in 2016 compared with 2011; however, the proportion of inpatients with HCAIs or on antibiotics did not differ significantly.

CONCLUSION

The burden of HCAIs in English hospitals increased slightly between 2011 and 2016. However, the proportion of inpatients with HCAIs or on antibiotics did not differ significantly.

Exposure and Health Effects of Bacteria in Healthcare Units: An Overview

Healthcare units consist of numerous people circulating daily, such as workers, patients, and companions, and these people are vehicles for the transmission of microorganisms, such as bacteria. Bacteria species may have different allergenic, pathogenic, infectious, or toxic properties that can affect humans. Hospital settings foment the proliferation of bacteria due to characteristics present in the indoor hospital environment. This review article aims to identify the potential health effects caused by bacterial contamination in the context of healthcare units, both in patients and in workers. A search was carried out for articles published in PubMed, Web of Science and Scopus, between 1 January 2000 and 31 October 2021, using the descriptor hospital exposure assessment bacteria. This bibliographic research found a total of 13 articles. Bacteria transmission occurs mainly due to the contact between healthcare workers and patients or through the handling of/contact with contaminated instruments or surfaces. The most common bacterial contaminants are Escherichia coli, Pseudomonas aeruginosa, Staphylococcus spp., Staphylococcus aureus and Micrococcus luteus, and the principal health effects of these contaminants are hospital-acquired infections and infections in immunocompromised people. A tight control of the disinfection methods is thus required, and its frequency must be increased to remove the microbial contamination of wards, surfaces and equipment. A better understanding of seasonal variations is important to prevent peaks of contamination.

Healthcare-Associated Infections and Antibiotics Consumption: A Comparison of Point Prevalence Studies and Intervention Strategies

This study compares healthcare-associated infections (HAIs) prevalence and antimicrobial consumption (AMC) from surveys conducted in 2016 and 2019 in an Italian hospital for acute care. HAIs prevalence was 7.1% in both surveys, while patients were under antibiotic treatment slightly increased from 2016 to 2019, from 42.6% to 43.7%, respectively. In the survey of 2016, HAIs risk factors were fatal McCabe score and hospitalization longer than two weeks, while CVC and urinary catheter in that conducted in 2019. In both surveys, CVC and peripheral venous catheter resulted associated to AMC. HAIs and AMC remained stable although the hospital undergone a complexity reduction in the second survey, remarking that critical actions are strictly required implementing infection control practices and antimicrobial stewardship.

Multicenter point prevalence evaluation of the utilization and safety of drug therapies for COVID-19 at the onset of the pandemic timeline in the United States

KEY POINTS

In a multicenter point-prevalence study, we found that the rate of supportive care was high; among those receiving COVID-19 drug therapies, adverse reactions occurred in 12% of patients.

PURPOSE

There are currently no FDA-approved medications for the treatment of coronavirus disease 2019 (COVID-19). At the onset of the pandemic, off-label medication use was supported by limited or no clinical data. We sought to characterize experimental COVID-19 therapies and identify safety signals during this period.

METHODS

We conducted a noninterventional, multicenter, point prevalence study of patients hospitalized with suspected/confirmed COVID-19. Clinical and treatment characteristics within a 24-hour window were evaluated in a random sample of up to 30 patients per site. The primary objective was to describe COVID-19-targeted therapies. The secondary objective was to describe adverse drug reactions (ADRs).

RESULTS

A total of 352 patients treated for COVID-19 at 15 US hospitals From April 18 to May 8, 2020, were included in the study. Most patients were treated at academic medical centers (53.4%) or community hospitals (42.6%). Sixty-seven patients (19%) were receiving drug therapy in addition to supportive care. Drug therapies used included hydroxychloroquine (69%), remdesivir (10%), and interleukin-6 antagonists (9%). Five patients (7.5%) were receiving combination therapy. The rate of use of COVID-19-directed drug therapy was higher in patients with vs patients without a history of asthma (14.9% vs 7%, P = 0.037) and in patients enrolled in clinical trials (26.9% vs 3.2%, P < 0.001). Among those receiving drug therapy, 8 patients (12%) experienced an ADR, and ADRs were recognized at a higher rate in patients enrolled in clinical trials (62.5% vs 22%; odds ratio, 5.9; P = 0.028).

CONCLUSION

While we observed high rates of supportive care for patients with COVID-19, we also found that ADRs were common among patients receiving drug therapy, including those enrolled in clinical trials. Comprehensive systems are needed to identify and mitigate ADRs associated with experimental COVID-19 treatments.

A nationwide assessment of the burden of healthcare-associated infections and antimicrobial use among surgical patients: results from Serbian point prevalence survey, 2017

BACKGROUND

As the only non-European Union (EU) country, Serbia participated in a second point prevalence survey of healthcare-associated infections (HAIs) and antimicrobial use (AMU) organized by the European Centre for Disease Prevention and Control (ECDC) in the EU countries. Here, we aimed to estimate the prevalence of HAI and AMU in patients who had recently undergone a surgery and to compare risk profile, HAI rates, and AMU among surgical patients and non-surgical patients.

METHODS

A national PPS was performed in 65 Serbian acute-care hospitals, in November 2017. In this paper, the data of 61 hospitals for adult acute-care were analyzed. To ensure the comparability of study design we used the Serbian translation of ECDC case definitions and ECDC PPS protocol. The trained infection control staff, led by a hospital coordinator, reviewed medical records to identify HAI active at the time of the survey and AMU. Only inpatients admitted to the ward before 8 a.m. on the day if the survey were included.

RESULTS

A total of 12,478 patients from 61 hospitals for adult acute-care were eligible for inclusion in this study. Significantly higher proportions of surgical patients were female, belonged to the 60-to-79 age group, and were less severely ill. Also, extrinsic factors (invasive devices, hospitalization at the ICU, and prior antibiotics therapy) were more frequent in surgical patients. Prevalence of HAIs was higher among surgical patients (261/3626; 7.2%) than among non-surgical patients (258/8852; 2.9%) (p < 0.0001). The highest prevalence of all HAIs was noted in patients who had kidney transplantation (4/11; 36.4%), while SSIs were the most prevalent among patients who had peripheral vascular bypass surgery (3/15; 20.0%). Non-surgical patients received treatment for community-acquired infections in significantly higher proportion (2664/8852; 64.3) (p < 0.001). Surgical prophylaxis for more than 1 day was applied in 71.4% of surgical patients.

CONCLUSION

We have provided an insight into the burden of HAIs and AMU among Serbia acute-care hospitals, and highlighted several priority areas and targets for quality improvement.

Point-prevalence surveys of hospital-acquired infections in a Chinese cancer hospital: From 2014 to 2018

BACKGROUND

Both hospital-acquired infection (HAI) and cancer represents major health concerns worldwide, but there is a paucity of data describing HAI in Chinese cancer patients. The objective of this study is to demonstrate the prevalence, causative agents, antimicrobial use and risk factors for HAI in a cancer hospital in Southwestern China.

METHODS

We use the criteria of the Ministry of Health of the People's Republic of China to define hospital-acquired infections. One-day cross-sectional surveys were annually conducted from 2014 to 2018. Trained staff collected hospital-acquired infections, antimicrobial use and clinical characteristics data of inpatients. Multivariate logistic regression was used to determine the potential risk factors associated with HAIs.

RESULTS

Of the 6717 patients surveyed, there were 140 patients (2.1%, 95% confidence interval, 1.7-2.4%) with 144 distinct HAIs. Lower respiratory tract infections (47, 32.6%) and surgical-site infections (29, 20.1%) were the most common HAIs. Escherichia coli was the most common pathogen (29.6%). Risk factors for HAI included younger age (<18 years) or older age (>65 years), hospitalization in the intensive care unit, presence of central catheter and undergoing surgery in the previous 30 days. The overall prevalence of patients receiving antimicrobial agents was 15.2%.

CONCLUSION

To control hospital-acquired infections in cancer patients, surveillance and prevention strategies to infections associated with central catheters or related to surgery should be augmented.

Skin and soft tissue infections and current antimicrobial prescribing practices in Australian aged care residents

To determine the burden of skin and soft tissue infections (SSTI), the nature of antimicrobial prescribing and factors contributing to inappropriate prescribing for SSTIs in Australian aged care facilities, SSTI and antimicrobial prescribing data were collected via a standardised national survey. The proportion of residents prescribed ⩾1 antimicrobial for presumed SSTI and the proportion whose infections met McGeer et al. surveillance definitions were determined. Antimicrobial choice was compared to national prescribing guidelines and prescription duration analysed using a negative binomial mixed-effects regression model. Of 12 319 surveyed residents, 452 (3.7%) were prescribed an antimicrobial for a SSTI and 29% of these residents had confirmed infection. Topical clotrimazole was most frequently prescribed, often for unspecified indications. Where an indication was documented, antimicrobial choice was generally aligned with recommendations. Duration of prescribing (in days) was associated with use of an agent for prophylaxis (rate ratio (RR) 1.63, 95% confidence interval (CI) 1.08–2.52), PRN orders (RR 2.10, 95% CI 1.42–3.11) and prescription of a topical agent (RR 1.47, 95% CI 1.08–2.02), while documentation of a review or stop date was associated with reduced duration of prescribing (RR 0.33, 95% CI 0.25–0.43). Antimicrobial prescribing for SSTI is frequent in aged care facilities in Australia. Methods to enhance appropriate prescribing, including clinician documentation, are required.

Point prevalence survey of antimicrobial use and healthcare-associated infections in Belgian acute care hospitals: results of the Global-PPS and ECDC-PPS 2017

Background

The point prevalence survey of healthcare-associated infections (HAIs) and antimicrobial use organized by the European Centre for Disease Prevention and Control (ECDC-PPS) and the Global Point Prevalence Survey of antimicrobial consumption (Global-PPS) were simultaneously performed in Belgian acute care hospitals in 2017.

Methods

Belgian acute care hospitals were invited to participate in either the ECDC or Global-PPS. Hospital/ward/patient-level data were collected between September-December 2017. All patients present in the wards at 8 a.m. on the day of the PPS were included. The data of the ECDC and Global-PPS on antimicrobial consumption were pooled. Detailed data on HAIs were analysed for ECDC-PPS.

Results

Overall, 110 Belgian acute care hospital sites participated in the ECDC and Global-PPS (countrywide participation rate: 81.4%, 28,007 patients). Overall, a crude prevalence of patients with at least one antimicrobial of 27.1% (95% confidence interval (CI) 26.5-27.6%) was found. The most frequently reported indications were pneumonia (23.2%), urinary tract infections (15.2%) and skin and soft tissue infections (11.9%). The reason for antimicrobial use was recorded for 81.9% of the prescriptions, a stop/review date for 40.8% and compliance with local antibiotic guidelines for 76.6%. In the ECDC-PPS, the crude prevalence of patients with at least one HAI was 7.3% (95%CI 6.8-7.7%). Most frequently reported HAIs were pneumonia (21.6%) and urinary tract infections (21.3%).

Conclusions

HAI and antimicrobial use prevalence remained stable in comparison with the previous PPS (7.1% and 27.4% in 2011 and 2015, respectively). Belgian hospitals should be further stimulated to set local targets to improve antibiotic prescribing and reduce HAI.

Identifying hospital-acquired infections using retrospective record review from the Irish National Adverse Events Study (INAES) and European point prevalence survey case definitions

BACKGROUND

Point prevalence surveys (PPSs) collect data on hospital-acquired infections (HAIs) at one point in time but do not provide information on incidence over the entire admission or impact on patients or healthcare resources. Retrospective record review examines the entire admission to determine adverse event prevalence, incidence, preventability, physical impairment and additional length of stay.

AIM

To establish whether European HAI surveillance definitions can be applied to the Irish National Adverse Events Study (INAES) retrospective record review data to determine HAI burden.

METHODS

In the INAES, 1574 admissions were reviewed using a two-stage methodology and 247 adverse events were found. These were examined against European HAI case definitions to determine whether the event was an HAI. Results were compared with the 2011/12 European PPS data for Ireland.

FINDINGS

The prevalence of HAI adverse events in INAES was 4.4% (95% confidence interval (CI) 3.1-6.1%) with an incidence of 3.8 (95% CI 2.5-5.2) HAI adverse events per 100 admissions. The PPS HAI prevalence for Ireland was 5.2%. HAI types and micro-organisms were similar in INAES and the PPS. Approximately three-quarters of INAES HAI adverse events were preventable, 7% caused permanent impairment and 7% contributed to death. A mean of 10 additional bed days were attributed to HAI adverse events, equivalent to €9400 per event.

CONCLUSION

Retrospective record review is an accurate source of information on HAI incidence, preventability and impact that complements PPS prevalence rates. HAI adverse events result in higher costs to the healthcare system than other adverse events.

Reducing the risk of healthcare-associated infections through Lean Six Sigma: The case of the medicine areas at the Federico II University Hospital in Naples (Italy)

RATIONALE, AIMS, AND OBJECTIVES

Lean Six Sigma (LSS) has been recognized as an effective management tool for improving healthcare performance. Here, LSS was adopted to reduce the risk of healthcare-associated infections (HAIs), a critical quality parameter in the healthcare sector.

METHODS

Lean Six Sigma was applied to the areas of clinical medicine (including general medicine, pulmonology, oncology, nephrology, cardiology, neurology, gastroenterology, rheumatology, and diabetology), and data regarding HAIs were collected for 28,000 patients hospitalized between January 2011 and December 2016. Following the LSS define, measure, analyse, improve, and control cycle, the factors influencing the risk of HAI were identified by using typical LSS tools (statistical analyses, brainstorming sessions, and cause-effect diagrams). Finally, corrective measures to prevent HAIs were implemented and monitored for 1 year after implementation.

RESULTS

Lean Six Sigma proved to be a useful tool for identifying variables affecting the risk of HAIs and implementing corrective actions to improve the performance of the care process. A reduction in the number of patients colonized by sentinel bacteria was achieved after the improvement phase.

CONCLUSIONS

The implementation of an LSS approach could significantly decrease the percentage of patients with HAIs.

Comparison of Data Collection for Healthcare-Associated Infection Surveillance in Nursing Homes

OBJECTIVE

To facilitate surveillance and describe the burden of healthcare-associated infection (HAI) in nursing homes (NHs), we compared the quality of resident-level data collected by NH personnel and external staff.

DESIGN

A 1-day point-prevalence survey

SETTING AND PARTICIPANTS

Overall, 9 nursing homes among 4 Centers for Disease Control and Prevention (CDC) Emerging Infection Program (EIP) sites were included in this study.

METHODS

NH personnel collected data on resident characteristics, clinical risk factors for HAIs, and the presence of 3 HAI screening criteria on the day of the survey. Trained EIP surveillance officers collected the same data elements via retrospective medical chart review for comparison; surveillance officers also collected available data to identify HAIs (using revised McGeer definitions). Overall agreement was calculated among residents identified by both teams with selected risk factors and HAI screening criteria. The impact of using NH personnel to collect screening criteria on HAI prevalence was assessed.

RESULTS

The overall prevalence of clinical risk factors among the 1,272 residents was similar between NH personnel and surveillance officers, but the level of positive agreement (residents with factors identified by both teams) varied between 39% and 87%. Surveillance officers identified 253 residents (20%) with ≥1 HAI screening criterion, resulting in 67 residents with an HAI (5.3 per 100 residents). The NH personnel identified 152 (12%) residents with ≥1 HAI screening criterion; 42 residents had an HAI (3.5 per 100 residents).

CONCLUSION

We identified discrepancies in resident-level data collection between surveillance officers and NH personnel, resulting in varied estimates of the HAI prevalence. These findings have important implications for the design and implementation of future HAI prevalence surveys.

Infect Control Hosp Epidemiol 2016;1440–1445

Sensitivity and specificity of the method used for ascertainment of healthcare-associated infections in the second Slovenian national prevalence survey

Introduction

The second Slovenian national healthcare-associated infections (HAIs) prevalence survey (SNHPS) was conducted in acute-care hospitals in 2011. The objective was to assess the sensitivity and specificity of the method used for the ascertainment of six types of HAIs (bloodstream infections, catheter-associated infections, lower respiratory tract infections, pneumoniae, surgical site infections, and urinary tract infections) in the University Medical Centre Ljubljana (UMCL).

Methods

A cross-sectional study was conducted in patients surveyed in the SNHPS in the UMCL using a retrospective medical chart review (RMCR) and European HAIs surveillance definitions. Sensitivity and specificity of the method used in the SNHPS using RMCR as a reference was computed for ascertainment of patients with any of the six selected types of HAIs and for individual types of HAIs. Agreement between the SNHPS and RMCR results was analyzed using Cohen’s kappa coefficient.

Results

1474 of 1742 (84.6%) patients surveyed in the SNHPS were included in RMCR. The sensitivity of the SNHPS method for detecting any of six HAIs was 90% (95% confidence interval (CI): 81%-95%) and specificity 99% (95% CI: 98%-99%). The sensitivity by type of HAI ranged from 63% (lower respiratory tract infections) to 92% (bloodstream infections). Specificity was at least 99% for all types of HAIs. Agreement between the two data collection approaches for HAIs overall was very good (κ=0.83).

Conclusions

The overall sensitivity of SNHPS collection method for ascertaining HAIs overall was high and the specificity was very high. This suggests that the estimated prevalence of HAIs in the SNHPS was credible.

Annual surveys for point-prevalence of healthcare-associated infection in a tertiary hospital in Beijing, China, 2012-2014

Background

This study aimed to investigate the prevalence of healthcare-associated infection (HAI) in the China-Japan Friendship Hospital, a tertiary level hospital in Beijing, China.

Methods

We defined HAI using the criteria established by the Ministry of Health of the People’s Republic of China. Three cross-sectional surveys were conducted from 2012 to 2014. Inpatients who had been hospitalized for at least 48 h were surveyed. Information on HAI prevalence, isolated pathogens and use of antibiotics were collected. Logistic regression models were used to assess the associations between HAI and potential risk factors.

Results

During three cross-sectional surveys, a total number of 4,029 patients were included (1,233 patients in 2012, 1,220 patients in 2013 and 1,576 patients in 2014). The overall prevalence of patients with HAI was 3.6 % (95 % confidence interval (CI) 3.1 %–4.2 %). Respiratory tract infections were the most common type (64.7 %) of HAIs, followed by urinary tract infections (12.6 %) and bloodstream infections (5.4 %). HAI occurrences were significantly associated with male sex (odds ratio (OR) = 2.25, 95 % CI 1.53-3.32), age over 85 years (OR = 4.74, 95 % CI 2.54–8.83), hospitalization in the intensive care units (ICUs) (OR = 2.42, 95 % CI 1.31–4.49), indwelling urinary catheter (OR = 4.21, 95 % CI 2.46–7.20) and mechanical ventilation (OR = 2.31, 95 % CI 1.30–4.09). Gram-negative bacteria were found to be the most isolated pathogens (67.1 %), with gram-positive bacteria and fungi accounted for 20.3 % and 10.5 %, respectively. Antibiotics were administered to 34.3 % of the included patients over the study period.

Conclusions

The overall HAI prevalence in our hospital is similar to previous studies that were conducted in other areas of China, and the respiratory tract infection should be the priority in HAI reduction control within China. We should focus HAI reduction efforts on patients with advanced age, hospitalization in the ICU and indwelling devices.

Trial of a novel plasma gas disinfection system (Radica) to reduce mattress residual bacterial contamination in the acute hospital setting: a preliminary study

BACKGROUND

In routine clinical practice, mattresses are manually cleaned using specialised cleaning and high-level disinfecting fluids. While effective against a wide range of organisms, the success of this approach is dependent on a thorough and complete application and is likely to be susceptible to human error and thus variable. The efficacy of available infection control measures to reduce such mattress contamination is unknown as it is not subject to quality control measures. There is a pressing need to identify more effective methods to prevent cross contamination within the medical environment, given the lack of available treatment strategies.

AIM

The purpose of this study is to investigate the ability of a new technology, gaseous technology, to reduce colonization levels, compared to standard cleaning, and so attenuate superficial nosocomial infections.

METHODS

We conducted a prospective, single-centre, open-label, non-randomized trial with blinded outcome assessments, comparing the standard cleaning of hospital mattresses with a novel plasma based disinfection system Radica™, followed by a standard post-cleaning culturing protocol (five swabs/mattress).

RESULTS

The median (interquartile range) maximal colony count per mattress for the 20 Radica versus 7 routinely cleaned mattresses was 1 (1-2.7) versus Too-Numerous-to-Count (TNTC) (32-TNTC), respectively, p = 0.002. Of the 20 Radica™ treated mattresses, 12 (60 %) had no positive culture result while all of the standard cleaned mattresses had at least two positive cultures.

CONCLUSION

The plasma based Radica disinfection system reduces mattress bacterial colonization levels as compared to routine cleaning. This is a potentially important technology in the health care system to reduce surface colonisation and hence nosocomial infections.

Using surveillance data to reduce healthcare-associated infection: a qualitative study in Sweden

INTRODUCTION

Healthcare-associated infection (HAI) surveillance data can be used to estimate the scope, spread and location of infections, monitor trends, evaluate preventive efforts, and improve practices, policy and facility planning. In Sweden, national point prevalence surveys (PPS) have been conducted twice yearly in all county councils since 2008.

AIM

The aim of this study was to identify key obstacles concerning the HAI surveillance process.

METHODS

Twenty-two infection control practitioners (ICPs) from all county councils in Sweden were interviewed, using semi-structured interview guides. Data were analysed using qualitative content analysis.

RESULTS

Sixteen types of obstacles pertaining to four surveillance stages were identified. Most obstacles were associated with the first two stages, which meant that the latter stages of this process, i.e. the use of the results to reduce HAI, were underdeveloped. The ICPs observed scepticism towards both the PPS methodology itself and the quality of the HAI data collected in the PPS, which hinders HAI surveillance realising its full potential in Swedish healthcare.

Case-Mix Adjustment Approach to Benchmarking Prevalence Rates of Nosocomial Infection in Hospitals in Cyprus and Greece

Objective.

To examine the effect of heterogeneous case mix for a benchmarking analysis and interhospital comparison of the prevalence rates of nosocomial infection.

Design.

Cross-sectional survey.

Setting.

Eleven hospitals located in Cyprus and in the region of Crete in Greece.

Methods.

The survey included all inpatients in the medical, surgical, pediatric, and gynecology-obstetrics wards, as well as those in intensive care units. Centers for Disease Control and Prevention criteria were used to define nosocomial infection. The information collected for all patients included demographic characteristics, primary admission diagnosis, Karnofsky functional status index, Charlson comorbidity index, McCabe- Jackson severity of illness classification, use of antibiotics, and prior exposures to medical and surgical risk factors. Outcome data were also recorded for all patients. Case mix-adjusted rates were calculated by using a multivariate logistic regression model for nosocomial infection risk and an indirect standardization method.

Results.

The overall prevalence rate of nosocomial infection was 7.0% (95% confidence interval, 5.9%–8.3%) among 1,832 screened patients. Significant variation in nosocomial infection rates was observed across hospitals (range, 2.2%–9.6%). Logistic regression analysis indicated that the mean predicted risk of nosocomial infection across hospitals ranged from 3.7% to 10.3%, suggesting considerable variation in patient risk. Case mix-adjusted rates ranged from 2.6% to 12.4%, and the relative ranking of hospitals was affected by case-mix adjustment in 8 cases (72.8%). Nosocomial infection was significantly and independently associated with mortality (adjusted odds ratio, 3.6 [95% confidence interval, 2.1–6.1]).

Conclusion.

The first attempt to rank the risk of nosocomial infection in these regions demonstrated the importance of accounting for heterogeneous case mix before attempting interhospital comparisons.

Antimicrobial activity of LFF571 and three treatment agents against Clostridium difficile isolates collected for a pan-European survey in 2008: clinical and therapeutic implications

OBJECTIVES

In November 2008, a study was performed with support from the European Centre for Disease Prevention and Control (ECDC) to obtain an overview of Clostridium difficile infections (CDIs) in European hospitals. A collection of 398 C. difficile isolates obtained from this hospital-based survey was utilized to identify antimicrobial susceptibility patterns of common C. difficile PCR ribotypes across Europe.

METHODS

The MICs of three approved therapeutic agents (vancomycin, metronidazole and fidaxomicin) and LFF571 (a novel semi-synthetic thiopeptide antibiotic) were determined by the agar dilution method.

RESULTS

MICs of fidaxomicin and LFF571 were in general 2-4-fold lower than those of vancomycin and metronidazole. Isolates belonging to clade 2, including the hypervirulent ribotype 027, had one-dilution higher MIC50 and MIC90 values for fidaxomicin and metronidazole, whereas similar MIC values were observed for vancomycin and LFF571. Isolates belonging to C. difficile PCR ribotype 001 were more susceptible to fidaxomicin than other frequently found PCR ribotypes 014/020 and 078. Six isolates from three different countries had a metronidazole MIC of 2 mg/L. Four of the six isolates were characterized as PCR ribotype 001.

CONCLUSIONS

There was no evidence of in vitro resistance of C. difficile to any of the four agents tested. However, the results suggest type-specific differences in susceptibility for the treatment agents we investigated. Continuous surveillance of C. difficile isolates in Europe is needed to determine the possible clinical implications of ribotype-specific changes in susceptibility to therapeutic agents.

Current status of Clostridium difficile infection epidemiology

The dramatic changes in the epidemiology of Clostridium difficile infection (CDI) during recent years, with increases in incidence and severity of disease in several countries, have made CDI a global public health challenge. Increases in CDI incidence have been largely attributed to the emergence of a previously rare and more virulent strain, BI/NAP1/027. Increased toxin production and high-level resistance to fluoroquinolones have made this strain a very successful pathogen in healthcare settings. In addition, populations previously thought to be at low risk are now being identified as having severe CDI. Recent genetic analysis suggests that C. difficile has a highly fluid genome with multiple mechanisms to modify its content and functionality, which can make C. difficile adaptable to environmental changes and potentially lead to the emergence of more virulent strains. In the face of these changes in the epidemiology and microbiology of CDI, surveillance systems are necessary to monitor trends and inform public health actions.

Prevalence of nosocomial infections in acute care hospitals in Catalonia (VINCat Program)

The first objective of the Catalonian Nosocomial Infection Surveillance Program (VINCat) is to monitor the prevalence (%) of patients with nosocomial infections (NI), patients undergoing urinary catheterization with closed circuit drainage (%) and patients undergoing antibiotic treatment (%). We present the results for the period 2008-2010. Comprehensive and point annual prevalence surveys were conducted that included conventionally hospitalized patients in acute care hospitals belonging to the VINCat Program. The number of participating hospitals was 46 (2008), 48 (2009) and 61 (2010), most belonging to the Network of Public Use Hospitals of Servei Català de la Salut. The results are presented globally and by hospital size (<200 beds, 200-500 beds, >500 beds). The prevalence of patients with active NI acquired during the current or the previous hospitalization (global NI/P%) was 7.6 (2008), 6.2 (2009) and 6.3 (2010). The prevalence of patients with active NI acquired during the current (actual NI/P%) was 6.2 (2008), 4.7 (2009) and 4.6 (2010).The results by hospital size shows that the variation occurred mainly in <200 beds hospitals. The proportion of closed circuit urinary catheterization use was 90.2%. The use of antibiotics varied between 34.6% and 37.6%, with no differences due to hospital size. The global prevalence of NI provides information on the burden of NI at the institutional and regional level. Between 17.3% and 26.9% of patients with NI at the time of the study had acquired it in a previous hospitalization at the same institution.

Changing epidemiology of Clostridium difficile infection following the introduction of a national ribotyping-based surveillance scheme in England

BACKGROUND

Marked increases in Clostridium difficile infection (CDI) incidence, driven by epidemic strain spread, is a global phenomenon.

METHODS

The Clostridium difficile Ribotyping Network (CDRN) was established in 2007 as part of enhanced CDI surveillance in England, to facilitate the recognition and control of epidemic strains. We report on changes in CDI epidemiology in England in the first 3 years of CDRN.

RESULTS

CDRN received 12,603 fecal specimens, comprising significantly (P < .05) increasing numbers and proportions of national CDI cases in 2007-2008 (n = 2109, 3.8%), 2008-2009 (n = 4774, 13.2%), and 2009-2010 (n = 5720, 22.3%). The C. difficile recovery rate was 90%, yielding 11,294 isolates for ribotyping. Rates of 9 of the 10 most common ribotypes changed significantly (P < .05) during 2007-2010. Clostridium difficile ribotype 027 predominated, but decreased markedly from 55% to 36% and 21% in 2007-2008, 2008-2009, and 2009-2010, respectively. The largest regional variations in prevalence occurred for ribotypes 027, 002, 015, and 078. Cephalosporin and fluoroquinolone use in CDI cases was reported significantly (P < .05) less frequently during 2007-2010. Mortality data were subject to potential reporting bias, but there was a significant decrease in CDI-associated deaths during 2007-2010, which may have been due to multiple factors, including reduced prevalence of ribotype 027.

CONCLUSIONS

Access to C. difficile ribotyping was associated with significant changes in the prevalence of epidemic strains, especially ribotype 027. These changes coincided with markedly reduced CDI incidence and related mortality in England. CDI control programs should include prospective access to C. difficile typing and analysis of risk factors for CDI and outcomes.

The accuracy and validity of a weekly point-prevalence survey for evaluating the trend of hospital-acquired infections in a university hospital in Turkey

OBJECTIVE

To evaluate the validity of a weekly point-prevalence survey (WPS) by comparing it with a prospective-active incidence survey (PIS).

METHODS

WPS and PIS were conducted at a tertiary referral hospital between January and December 2006. Each Wednesday, an infection control team reviewed all clinical records of patients with hospital-acquired infections (HAIs) by WPS. Routine PIS was conducted with daily visits by the same team. The Rhame and Sudderth formula was used for converting the data between WPS and PIS.

RESULTS

During the study period, 1287 HAIs were detected in 37 466 patients by WPS. The mean observed prevalence and calculated prevalence were 5.42% and 5.45%, respectively. The reanimation intensive care unit (ICU) (49.4%) and burns unit (27.6%) had the highest prevalence rates. Pneumonia (0.94%) and urinary tract infections (0.37%) were the most frequent infections. Overall 602 HAIs were detected in 545 patients by PIS. The mean observed incidence and calculated incidence were 2.42/1000-admissions and 2.41/1000-admissions, respectively. The Critical care ICU (37.0/1000-admissions) and burns unit (24.8/1000-admissions) had the highest incidences of HAI. Pneumonia (0.64/1000-admissions) and urinary tract infections (0.37/1000-admissions) were the most frequent infections.

CONCLUSIONS

This study confirms a close relationship between prevalence and incidence data. WPS may be a useful method for following HAIs when PIS cannot be performed.

Factors associated with seroprevalence of hepatitis C among dentists at a large Brazilian city

BACKGROUND

The aim of the present study was to investigate the seroprevalence and sociodemographic data, health-related and occupational factors and other correlates of sero-posivity among dentists in the city of Belo Horizonte, MG, Brazil.

METHODS

A cross-sectional survey was carried out with 1302 dentists in Belo Horizonte, Brazil. All dentists were tested for anti-HCV using a commercially available enzyme-linked immunosorbent assay (ELISA). Individuals positive for anti-HCV were recalled for further evaluation. The presence of HCV RNA in anti-HCV-positive samples was assessed using reverse transcription-polymerase chain reaction (RT-PCR). Data on demographic, behavioural and occupational exposure aspects were collected through questionnaires.

RESULTS

The seroprevalence of anti-HCV was 0.9% (95% IC 0.5-1.7%). The factors associated to the prevalence of hepatitis C were history of blood transfusion (p = 0.002) and having undergone a test for hepatitis C (p = 0.015).

CONCLUSIONS

The seroprevalence of anti-HCV among dentists is low. Moreover, no occupational exposure was associated to the seroprevalence of hepatitis C.

Nosocomial infections prevalence study in a Serbian university hospital

BACKGROUND/AIM

Nosocomial infections (NI) are a serious health problem resulting in an enromous burden of excess morbidity and mortaliti rates, and health care costs. The aim of this study was to assess the prevalence of NI and to identify groups of patients at special risk for NI in the University Clinical Center, Kragujevac, Serbia.

METHODS

A period prevalence study design was used in this study. A survey of NI included all patients hospitalized in all departments in the University Clinical Center, Kragujevac.

RESULTS

Among 764 patients surveyed, the global prevalence rate of patients with at least one NI was 6.2% (95% CI = 5.6-6.8), while the prevalence of NI was 7.1%. The most frequent infections were surgical site infections (14.1%; 95% CI = 12.9-15.3), followed by pneumonia (2.3%; 95% CI = 2.1-2.5) in surgical patients. In medical wards, the most common NI were skin and subcutaneous tissue infections (1.6%; 95% CI = 1.4-1.8), and urinary infections (1.4%; 95% CI = 1.3-1.5). Overall, 85.1% NI were culture-proven; the leading pathogens were Pseudomonas species (40.0%), followed by Staphylococcus species (25.0%), Escherichia coli (22.5%), Proteus mirabilis (17.5%) and Klebsiella-Enterobacter (12.5%). Multivariate logistic regression analysis identified 3 risk factors independently associated with NI appearance: hospital stay > or =8 days (p = 0.0015), urinary catheter (p = 0.0022) and antibiotic use (p < 0.001).

CONCLUSION

This study showed that NI are a serious health problem in our hospital. The most common infections were surgical site infections, followed by skin and subcutaneous tissue infection and urinary tract infections. Nosocomial infections were most common in patients in urological and orthopedic departments, and then in intensive care units. Prolonged hospital stay, urinary catheter and antibiotic exposure were risk factors independently associated with NI appearance.

[Nosocomial infection indicators]

Nosocomial infection indicators are a reflection of healthcare quality and patient safety in hospitals. Infection indicators are calculated using surveillance programs and/or systems. Current nosocomial infection surveillance systems are based on both prevalence and incidence studies. Since 1990 the EPINE prevalence study, promoted by the Spanish Society for Preventive Medicine, Public Health and Hygiene, has developed 25 nosocomial infection indicators in hospital patients in Spain. And since 1994 the ENVIN-HELICS incidence study, promoted by the Infectious Diseases Working Group of the Spanish Society for Intensive and Critical Care Medicine and Coronary Units, has developed nine ICU-acquired infection indicators in critical patients. Participation in both surveillance systems is voluntary and has gradually increased over the years. These two control systems present the results of two different situations in the area of nosocomial infection and each complements the other; in addition, they have helped to train health professionals and to raise their awareness of nosocomial infection and patient safety. This article presents the indicators obtained in 2007 through both surveillance programs as well as their standards of reference.

Spectrum of activity and mode of action of REP3123, a new antibiotic to treat Clostridium difficile infections

OBJECTIVES

The aim of this study was to characterize the antimicrobial profile of REP3123, a novel inhibitor of methionyl-tRNA synthetase (MetRS) in development for the treatment of Clostridium difficile infection.

METHODS

The spectrum of activity of REP3123 was determined by susceptibility testing of C. difficile and non-target organisms. The mode of action was studied by enzyme inhibition assays, macromolecular synthesis assays, target overexpression and selection of spontaneous resistant mutants.

RESULTS

REP3123 was active against a collection of 108 clinical isolates of C. difficile and against epidemic, moxifloxacin-resistant BI/NAP1/027 strains (MIC range=0.5-1 mg/L and MIC(90) = 1 mg/L). The spectrum of activity included clinically important aerobic Gram-positive cocci such as Staphylococcus aureus, Streptococcus pyogenes, Enterococcus faecalis and Enterococcus faecium (MIC(90)s < 1 mg/L), but REP3123 was not active against most Gram-negative bacteria. REP3123 targeted C. difficile MetRS with a calculated inhibition constant (K(i)) of 0.020 nM, and selectivity was >1000-fold over human mitochondrial and cytoplasmic MetRS. The specific mode of action within bacterial cells was demonstrated by macromolecular synthesis assays that showed inhibition of protein synthesis by REP3123, and by metS overexpression, which resulted in a 16-fold increase in MIC for REP3123. Spontaneous REP3123-resistant mutants of C. difficile (MICs, 4-128 mg/L) arose with frequencies of 10(-8)-10(-9) and harboured distinct point mutations within the metS gene, resulting in 13 different amino acid substitutions. Most of the MetRS substitutions caused reduced catalytic efficiency and a growth fitness burden.

CONCLUSIONS

REP3123 demonstrated a favourable microbiological profile and was found to target C. difficile with high specificity and selectivity.

The management of Clostridium difficile infection

INTRODUCTION/BACKGROUND

Clostridium difficile is the commonest cause of nosocomial diarrhoea. The epidemiology and clinical phenotype of the disease has dramatically changed with the global emergence of a virulent strain of C. difficile.

SOURCE

This review was compiled using data from individual studies and review articles identified from PubMed. The retrieved articles were also examined for additional references.

AREAS OF AGREEMENT

Appropriate and timely infection control measures are required to control C. difficile infection (CDI) in the hospital environment, and either oral metronidazole or vancomycin remains the mainstay of treatment depending on the severity of infection.

AREAS OF CONTROVERSY

The optimal method for diagnosing CDI remains unclear, as does the best therapeutic strategy for the management of multiple relapses. GROWING POINTS/AREAS TIMELY FOR DEVELOPING RESEARCH: Studies of new antimicrobial agents with activity against C. difficile are required to improve the management of multiply relapsing disease. The use of novel therapeutic approaches that do not require antimicrobials requires urgent research, including the use of immunological or vaccine-based regimen, bacteriotherapy or C. difficile-specific bacteriophages.

What have we learned about antimicrobial use and the risks for Clostridium difficile-associated diarrhoea?

Clostridium difficile is recognized as a major cause of antibiotic-associated diarrhoea and colitis. Antimicrobial agents have been repeatedly recognized as a causative risk for C. difficile-associated diarrhoea (CDAD) and more recently fluoroquinolones have been particularly implicated. Unfortunately, not all reports of antimicrobial associations with CDAD have excluded variables other than antimicrobial use. Prevention of CDAD usually involves infection control interventions and antimicrobial restriction policies may not be fully substantiated by currently available data; however, antimicrobial drug restriction seems prudent in outbreak situations.

A case-control study of community-associated Clostridium difficile infection

OBJECTIVES

The aim of this study was to determine the incidence of and risk factors for community-associated Clostridium difficile infection (CDI).

METHODS

Prospective surveillance of community-derived faecal samples for C. difficile cytotoxin, followed by a questionnaire-based case-control study in two distinct patient cohorts (one semi-rural and the other urban).

RESULTS

The proportion of randomly selected faecal samples positive for C. difficile cytotoxin was 2.1% in both patient cohorts (median ages 73 and 45 years for the urban and semi-rural cohorts, respectively). Exposure to antibiotics in the previous 4 weeks, particularly multiple agents (P < 0.001), aminopenicillins (P < 0.05) and oral cephalosporins (P < 0.05), was significantly more frequent among cases than controls. Hospitalization in the preceding 6 months was significantly associated with CDI (45% versus 23%; P = 0.022). However, almost half the cases had not received antibiotic therapy in the month before C. difficile detection, and approximately one-third neither had exposure to antibiotics nor recent hospitalization. Contact with infants aged < or =2 years was significantly associated with CDI (14% versus 2%; P = 0.02). Prior exposure to gastrointestinal-acting drugs (proton pump inhibitor, H2 antagonist or non-steroidal anti-inflammatory) was not significantly more common in CDI cases. C. difficile PCR ribotype 001 caused 60% and 13% of urban and semi-rural community-associated CDI cases, respectively.

CONCLUSIONS

Reliance on antibiotic history and age (> or =65 years) will contribute to missed diagnoses of community-associated CDI. Potential risk factors for community-associated CDI should be explored further to explain the large proportion of cases not linked to recent antibiotic therapy or hospitalization.

Prevalence of nursing home-associated infections in the Department of Veterans Affairs nursing home care units

BACKGROUND

The Department of Veterans Affairs (VA) is the largest single provider of long-term care in the United States. The prevalence of nursing home-associated infections (NHAIs) among residents of VA nursing home care units (NHCUs) is not known.

METHODS

A Web-based point prevalence survey of NHAIs using modified Centers for Disease Control and Prevention definitions for health care-associated infections was conducted in the VA's 133 NHCUs on November 9, 2005.

RESULTS

From a total population of 11,475 NHCU residents, 591 had at least 1 NHAI for a point prevalence rate of 5.2%. Urinary tract infection, asymptomatic bacteriuria, pneumonia, skin infection, gastroenteritis, and soft tissue infection were most prevalent, constituting 72% of all NHAIs. A total of 2817 residents (24.5%) had 1 or more indwelling device. Of these 2817 residents with an indwelling device(s), 309 (11.0%) had 1 or more NHAI. In contrast, the prevalence of NHAIs in residents without an indwelling device was 3.3%. Indwelling urinary catheter, percutaneous gastrostomy tube, intravenous peripheral line, peripherally inserted central catheter, and suprapubic urinary catheter were most common, accounting for 79.3% of all devices used.

CONCLUSION

There are effective infection surveillance and control programs in VA NHCUs with a point prevalence of NHAIs of 5.2%.

Antimicrobial resistance: resistance to antifungal agents: mechanisms and clinical impact

Despite advances in preventive, diagnostic, and therapeutic interventions, invasive fungal infections cause significant morbidity and mortality in immunocompromised patients. The burden of antifungal resistance in such high-risk patients is becoming a major concern. A better understanding of the mechanisms and clinical impact of antifungal resistance is essential to the prompt and efficient treatment of patients with invasive mycoses and to improving the outcome of such infections. Although recent guidelines have attempted to standardize antifungal susceptibility testing, limitations still exist as a result of the incomplete correlation between in vitro susceptibility and clinical response to treatment. Four major mechanisms of resistance to azoles have been identified, all of which rely on altered gene expression. Mechanisms responsible for polyene and echinocandin resistance are less well understood. In addition to discussing the molecular mechanisms of antifungal resistance, this article elaborates on the concept of clinical resistance, which is critical to the understanding of treatment failure in patients with invasive fungal infections.

Spread and epidemiology of Clostridium difficile polymerase chain reaction ribotype 027/toxinotype III in The Netherlands

BACKGROUND

After reports of emerging outbreaks in Canada and the United States, Clostridium difficile-associated disease (CDAD) due to polymerase chain reaction ribotype 027 was detected in 2 medium-to-large hospitals in The Netherlands in 2005.

METHODS

National surveillance was initiated to investigate the spread and the epidemiology of CDAD. Microbiologists were asked to send strains recovered from patients with a severe course of CDAD or recovered when an increased incidence of CDAD was noted. A standardized questionnaire was used to collect demographic, clinical, and epidemiological patient data. Strains were characterized by polymerase chain reaction ribotyping, toxinotyping, the presence of toxin genes, and antimicrobial susceptibility.

RESULTS

During the period from February 2005 through November 2006, 1175 stool samples from 863 patients were sent from 50 health care facilities. Of these patients, 218 (25.3%) had CDAD due to ribotype 027, and 645 patients (74.7%) had CDAD due to other ribotypes, mainly 001 (17.8%) and 014 (7.2%). Polymerase chain reaction ribotype 027 was more frequently present in general hospitals than in academic hospitals (odds ratio [OR], 4.38; 95% confidence interval [CI], 1.60-12.0). Outbreaks of CDAD were observed in 10 hospitals and in 1 nursing home. Patients infected with ribotype 027 were significantly older (OR, 2.18; 95% CI, 1.43-3.33), and significantly more patients used fluoroquinolones (OR, 2.88; 95% CI, 1.01-8.20), compared with those who were infected with other ribotypes. Clear trends were observed for more severe diarrhea (OR, 1.99; 95% CI, 0.83-4.73), higher attributable mortality (6.3% vs. 1.2%; OR, 3.30; 95% CI, 0.41-26.4), and more recurrences (OR, 1.44; 95% CI, 0.94-2.20).

CONCLUSIONS

Ribotype 027 was found in 20 (18.3%) of 109 hospitals in The Netherlands, with a geographic concentration in the western and central parts of the country. The clinical syndrome in patients with CDAD differed on the basis of ribotype. Thus, early recognition of the ribotype has benefits.

The challenges posed by reemerging Clostridium difficile infection

There have been recent, marked increases in the incidence and severity of Clostridium difficile-associated disease (CDAD). These may be attributable to the emergence of a hypervirulent strain of C. difficile that produces increased levels of toxins A and B, as well as an extra toxin known as "binary toxin." This previously uncommon strain has become epidemic, coincident with its development of increased resistance to fluoroquinolones, the use of which is increasingly associated with CDAD outbreaks. Although not necessarily related to this epidemic strain, unusually severe CDAD has been reported in populations that had previously been thought to be at low risk, including peripartum women and healthy persons living in the community. Challenges posed by the changing epidemiology of CDAD are compounded by current limitations in diagnostic testing, treatment, and infection control. Overcoming these challenges and limitations will require a concerted effort from a variety of sources, including an ongoing partnership between infectious disease clinicians and public health professionals.