Assessments and observations of infection prevention and control practices in US outpatient hemodialysis facilities, 2015-2018: important opportunities for improvement.

Infections cause substantial morbidity and mortality among patients receiving care in outpatient hemodialysis facilities. We describe comprehensive infection prevention assessments by US public health departments using standardized interview and observation tools. Results demonstrated how facility layouts can undermine infection prevention and that clinical practices often fall short of policies.

Characteristics of Patients With Initial Clostridioides difficile Infection (CDI) That Are Associated With Increased Risk of Multiple CDI Recurrences.

Background: Because interventions are available to prevent further recurrence in patients with recurrent Clostridioides difficile infection (rCDI), we identified predictors of multiple rCDI (mrCDI) in adults at the time of presentation with initial CDI (iCDI). Methods: iCDI was defined as a positive C difficile test in any clinical setting during January 2018-August 2019 in a person aged ≥18 years with no known prior positive test. rCDI was defined as a positive test ≥14 days from the previous positive test within 180 days after iCDI; mrCDI was defined as ≥2 rCDI. We performed multivariable logistic regression analysis. Results: Of 18 829 patients with iCDI, 882 (4.7%) had mrCDI; 437 with mrCDI and 7484 without mrCDI had full chart reviews. A higher proportion of patients with mrCDI than without mrCDI were aged ≥65 years (57.2% vs 40.7%; P < .0001) and had healthcare (59.1% vs 46.9%; P < .0001) and antibiotic (77.3% vs 67.3%; P < .0001) exposures in the 12 weeks preceding iCDI. In multivariable analysis, age ≥65 years (adjusted odds ratio [aOR], 1.91; 95% confidence interval [CI], 1.55-2.35), chronic hemodialysis (aOR, 2.28; 95% CI, 1.48-3.51), hospitalization (aOR, 1.64; 95% CI, 1.33-2.01), and nitrofurantoin use (aOR, 1.95; 95% CI, 1.18-3.23) in the 12 weeks preceding iCDI were associated with mrCDI. Conclusions: Patients with iCDI who are older, on hemodialysis, or had recent hospitalization or nitrofurantoin use had increased risk of mrCDI and may benefit from early use of adjunctive therapy to prevent mrCDI. If confirmed, these findings could aid in clinical decision making and interventional study designs.

Prevalence of Acinetobacter baumannii and Candida auris in Patients Receiving Mechanical Ventilation.

Importance: To date, only 1 statewide prevalence survey has been performed for Acinetobacter baumannii (2009) in the US, and no statewide prevalence survey has been performed for Candida auris, making the current burden of these emerging pathogens unknown. Objective: To determine the prevalence of A baumannii and C auris among patients receiving mechanical ventilation in Maryland. Design, Setting, and Participants: The Maryland Multi-Drug Resistant Organism Prevention Collaborative performed a statewide cross-sectional point prevalence of patients receiving mechanical ventilation admitted to acute care hospitals (n = 33) and long-term care facilities (n = 18) between March 7, 2023, and June 8, 2023. Surveillance cultures (sputum, perianal, arm/leg, and axilla/groin) were obtained from all patients receiving mechanical ventilation. Sputum, perianal, and arm/leg cultures were tested for A baumannii and antibiotic susceptibility testing was performed. Axilla/groin cultures were tested by polymerase chain reaction for C auris. Main Outcomes and Measures: Prevalence of A baumannii, carbapenem-resistant A baumannii (CRAB), and C auris. Prevalence was stratified by type of facility. Results: All 51 eligible health care facilities (100%) participated in the survey. A total of 482 patients receiving mechanical ventilation were screened for A baumannii and 470 were screened for C auris. Among the 482 patients who had samples collected, 30.7% (148/482) grew A baumannii, 88 of the 148 (59.5%) of these A baumannii were CRAB, and C auris was identified in 31 of 470 (6.6%). Patients in long-term care facilities were more likely to be colonized with A baumannii (relative risk [RR], 7.66 [95% CI, 5.11-11.50], P < .001), CRAB (RR, 5.48 [95% CI, 3.38-8.91], P < .001), and C auris (RR, 1.97 [95% CI, 0.99-3.92], P = .05) compared with patients in acute care hospitals. Nine patients (29.0%) with cultures positive for C auris were previously unreported to the Maryland Department of Health. Conclusions: A baumannii, carbapenem-resistant A baumannii, and C auris were common among patients receiving mechanical ventilation in both acute care hospitals and long-term care facilities. Both pathogens were significantly more common in long-term care facilities than in acute care hospitals. Patients receiving mechanical ventilation in long-term care facilities are a high-risk population for emerging pathogens, and surveillance and prevention efforts should be targeted to these facilities.

Epidemiology of Sepsis in US Children and Young Adults.

Background: Most multicenter studies of US pediatric sepsis epidemiology use administrative data or focus on pediatric intensive care units. We conducted a detailed medical record review to describe sepsis epidemiology in children and young adults. Methods: In a convenience sample of hospitals in 10 states, patients aged 30 days-21 years, discharged during 1 October 2014-30 September 2015, with explicit diagnosis codes for severe sepsis or septic shock, were included. Medical records were reviewed for patients with documentation of sepsis, septic shock, or similar terms. We analyzed overall and age group-specific patient characteristics. Results: Of 736 patients in 26 hospitals, 442 (60.1%) had underlying conditions. Most patients (613 [83.3%]) had community-onset sepsis, although most community-onset sepsis was healthcare associated (344 [56.1%]). Two hundred forty-one patients (32.7%) had outpatient visits 1-7 days before sepsis hospitalization, of whom 125 (51.9%) received antimicrobials ≤30 days before sepsis hospitalization. Age group-related differences included common underlying conditions (<5 years: prematurity vs 5-12 years: chronic pulmonary disease vs 13-21 years: chronic immunocompromise); medical device presence ≤30 days before sepsis hospitalization (1-4 years: 46.9% vs 30 days-11 months: 23.3%); percentage with hospital-onset sepsis (<5 years: 19.6% vs ≥5 years: 12.0%); and percentage with sepsis-associated pathogens (30 days-11 months: 65.6% vs 13-21 years: 49.3%). Conclusions: Our data suggest potential opportunities to raise sepsis awareness among outpatient providers to facilitate prevention, early recognition, and intervention in some patients. Consideration of age-specific differences may be important as approaches are developed to improve sepsis prevention, risk prediction, recognition, and management.

Outbreaks of SARS-CoV-2 Infections in Nursing Homes during Periods of Delta and Omicron Predominance, United States, July 2021-March 2022.

SARS-CoV-2 infections among vaccinated nursing home residents increased after the Omicron variant emerged. Data on booster dose effectiveness in this population are limited. During July 2021-March 2022, nursing home outbreaks in 11 US jurisdictions involving >3 infections within 14 days among residents who had received at least the primary COVID-19 vaccine(s) were monitored. Among 2,188 nursing homes, 1,247 outbreaks were reported in the periods of Delta (n = 356, 29%), mixed Delta/Omicron (n = 354, 28%), and Omicron (n = 536, 43%) predominance. During the Omicron-predominant period, the risk for infection within 14 days of an outbreak start was lower among boosted residents than among residents who had received the primary vaccine series alone (risk ratio [RR] 0.25, 95% CI 0.19-0.33). Once infected, boosted residents were at lower risk for all-cause hospitalization (RR 0.48, 95% CI 0.40-0.49) and death (RR 0.45, 95% CI 0.34-0.59) than primary vaccine-only residents.

Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) outbreaks in nursing homes involving residents who had completed a primary coronavirus disease 2019 (COVID-19) vaccine series-13 US jurisdictions, July-November 2021.

Among nursing home outbreaks of coronavirus disease 2019 (COVID-19) with ≥3 breakthrough infections when the predominant severe acute respiratory coronavirus virus 2 (SARS-CoV-2) variant circulating was the SARS-CoV-2 δ (delta) variant, fully vaccinated residents were 28% less likely to be infected than were unvaccinated residents. Once infected, they had approximately half the risk for all-cause hospitalization and all-cause death compared with unvaccinated infected residents.

Comparison of the Risk of Recurrent Clostridioides Difficile Infections Among Patients in 2018 Versus 2013.

Among persons with an initial Clostridioides difficile infection (CDI) across 10 US sites in 2018 compared with 2013, 18.3% versus 21.1% had ≥1 recurrent CDI (rCDI) within 180 days. We observed a 16% lower adjusted risk of rCDI in 2018 versus 2013 (P < .0001).

Practices and activities among healthcare personnel with severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection working in different healthcare settings-ten Emerging Infections Program sites, April-November 2020.

Healthcare personnel with severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection were interviewed to describe activities and practices in and outside the workplace. Among 2,625 healthcare personnel, workplace-related factors that may increase infection risk were more common among nursing-home personnel than hospital personnel, whereas selected factors outside the workplace were more common among hospital personnel.

Impact of Statewide Prevention and Reduction of Clostridioides difficile (SPARC), a Maryland public health-academic collaborative: an evaluation of a quality improvement intervention.

To evaluate changes in Clostridioides difficile incidence rates for Maryland hospitals that participated in the Statewide Prevention and Reduction of C. difficile (SPARC) collaborative. Pre-post, difference-in-difference analysis of non-randomised intervention using four quarters of preintervention and six quarters of postintervention National Healthcare Safety Network data for SPARC hospitals (April 2017 to March 2020) and 10 quarters for control hospitals (October 2017 to March 2020). Mixed-effects negative binomial models were used to assess changes over time. Process evaluation using hospital intervention implementation plans, assessments and interviews with staff at eight SPARC hospitals. Maryland, USA. All Maryland acute care hospitals; 12 intervention and 36 control hospitals. Participation in SPARC, a public health-academic collaborative made available to Maryland hospitals, with staggered enrolment between June 2018 and August 2019. Hospitals with higher C. difficile rates were recruited via email and phone. SPARC included assessments, feedback reports and ongoing technical assistance. Primary outcomes were C. difficile incidence rate measured as the quarterly number of C. difficile infections per 10 000 patient-days (outcome measure) and SPARC intervention hospitals' experiences participating in the collaborative (process measures). SPARC invited 13 hospitals to participate in the intervention, with 92% (n=12) participating. The 36 hospitals that did not participate served as control hospitals. SPARC hospitals were associated with 45% greater C. difficile reduction as compared with control hospitals (incidence rate ratio=0.55, 95% CI 0.35 to 0.88, p=0.012). Key SPARC activities, including access to trusted external experts, technical assistance, multidisciplinary collaboration, an accountability structure, peer-to-peer learning opportunities and educational resources, were associated with hospitals reporting positive experiences with SPARC. SPARC intervention hospitals experienced 45% greater reduction in C. difficile rates than control hospitals. A public health-academic collaborative might help reduce C. difficile and other hospital-acquired infections in individual hospitals and at state or regional levels.

Impact of a C. difficile infection (CDI) reduction bundle and its components on CDI diagnosis and prevention.

BACKGROUND: Published bundles to reduce Clostridioides difficile Infection (CDI) frequently lack information on compliance with individual elements. We piloted a computerized clinical decision support-based intervention bundle and conducted detailed evaluation of several intervention-related measures. METHODS: A quasi-experimental study of a bundled intervention was performed at 2 acute care community hospitals in Maryland. The bundle had five components: (1) timely placement in enteric precautions, (2) appropriate CDI testing, (3) reducing proton-pump inhibitor (PPI) use, (4) reducing high-CDI risk antibiotic use, and (5) optimizing use of a sporicidal agent for environmental cleaning. Chi-square and Kruskal-Wallis tests were used to compare measure differences. An interrupted time series analysis was used to evaluate impact on hospital-onset (HO)-CDI. RESULTS: Placement of CDI suspects in enteric precautions before test results did not change. Only hospital B decreased the frequency of CDI testing and reduced inappropriate testing related to laxative use. Both hospitals reduced the use of PPI and high-risk antibiotics. A 75% decrease in HO-CDI immediately postimplementation was observed for hospital B only. CONCLUSION: A CDI reduction bundle showed variable impact on relevant measures. Hospital-specific differential uptake of bundle elements may explain differences in effectiveness, and emphasizes the importance of measuring processes and intermediate outcomes.

Association between Socioeconomic Status and Incidence of Community-Associated Clostridioides difficile Infection - United States, 2014-2015.

We evaluated the association between socioeconomic status (SES) and community-associated Clostridioides difficile infection (CA-CDI) incidence across 2474 census tracts in 10 states. Highly correlated community-level SES variables were transformed into distinct factors using factor analysis. We found low SES communities were associated with higher CA-CDI incidence.

Evaluation of viral co-infections among patients with community-associated Clostridioides difficile infection.

We assessed viral co-infections in 155 patients with community-associated Clostridioides difficile infection in five U.S. sites during December 2012-February 2013. Eighteen patients (12%) tested positive for norovirus (n = 10), adenovirus (n = 4), rotavirus (n = 3), or sapovirus (n = 1). Co-infected patients were more likely than non-co-infected patients to have nausea or vomiting (56% vs 31%; p = 0.04), suggesting that viral co-pathogens contributed to symptoms in some patients. There were no significant differences in prior healthcare or medication exposures or in CDI complications.

Assessment of Health Care Exposures and Outcomes in Adult Patients With Sepsis and Septic Shock.

Importance: Current information on the characteristics of patients who develop sepsis may help in identifying opportunities to improve outcomes. Most recent studies of sepsis epidemiology have focused on changes in incidence or have used administrative data sets that provided limited patient-level data. Objective: To describe sepsis epidemiology in adults. Design, Setting, and Participants: This retrospective cohort study reviewed the medical records, death certificates, and hospital discharge data of adult patients with sepsis or septic shock who were discharged from the hospital between October 1, 2014, and September 30, 2015. The convenience sample was obtained from hospitals in the Centers for Disease Control and Prevention Emerging Infections Program in 10 states (California, Colorado, Connecticut, Georgia, Maryland, Minnesota, New Mexico, New York, Oregon, and Tennessee). Patients 18 years and older with discharge diagnosis codes for severe sepsis or septic shock were randomly selected. Data were analyzed between May 1, 2018, and January 31, 2019. Main Outcomes and Measures: The population's demographic characteristics, health care exposures, and sepsis-associated infections and pathogens were described, and risk factors for death within 30 days after sepsis diagnosis were assessed. Results: Among 1078 adult patients with sepsis (569 men [52.8%]; median age, 64 years [interquartile range, 53-75 years]), 973 patients (90.3%) were classified as having community-onset sepsis (ie, sepsis diagnosed within 3 days of hospital admission). In total, 654 patients (60.7%) had health care exposures before their hospital admission for sepsis; 260 patients (24.1%) had outpatient encounters in the 7 days before admission, and 447 patients (41.5%) received medical treatment, including antimicrobial drugs, chemotherapy, wound care, dialysis, or surgery, in the 30 days before admission. A pathogen associated with sepsis was found in 613 patients (56.9%); the most common pathogens identified were Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Clostridioides difficile. After controlling for other factors, an association was found between underlying comorbidities, such as cirrhosis (odds ratio, 3.59; 95% CI, 2.03-6.32), immunosuppression (odds ratio, 2.52; 95% CI, 1.81-3.52), vascular disease (odds ratio, 1.54; 95% CI, 1.10-2.15), and 30-day mortality. Conclusions and Relevance: Most adults experienced sepsis onset outside of the hospital and had recent encounters with the health care system. A sepsis-associated pathogen was identified in more than half of patients. Future efforts to improve sepsis outcomes may benefit from examination of health maintenance practices and recent health care exposures as potential opportunities among high-risk patients.

Treatment of Clostridioides difficile Infection and Non-compliance with Treatment Guidelines in Adults in 10 US Geographical Locations, 2013-2015.

BACKGROUND: Infectious Diseases Society of America/Society for Healthcare Epidemiology of America (IDSA/SHEA) guidelines describe recommended therapy for Clostridioides difficile infection (CDI). OBJECTIVE: To describe CDI treatment and, among those with severe CDI, determine predictors of adherence to the 2010 IDSA/SHEA treatment guidelines. DESIGN: We analyzed 2013-2015 CDI treatment data collected through the Centers for Disease Control and Prevention's Emerging Infections Program. Generalized linear mixed models were used to identify predictors of guideline-adherent therapy. PATIENTS: A CDI case was defined as a positive stool specimen in a person aged ≥ 18 years without a positive test in the prior 8 weeks; severe CDI cases were defined as having a white blood cell count ≥ 15,000 cells/µl. MAIN MEASURES: Prescribing and predictors of guideline-adherent CDI therapy for severe disease. KEY RESULTS: Of 18,243 cases, 14,257 (78%) were treated with metronidazole, 7683 (42%) with vancomycin, and 313 (2%) with fidaxomicin. The median duration of therapy was 14 (interquartile range, 11-15) days. Severe CDI was identified in 3250 (18%) cases; of 3121 with treatment data available, 1480 (47%) were prescribed guideline-adherent therapy. Among severe CDI cases, hospital admission (adjusted odds ratio [aOR] 2.48; 95% confidence interval [CI] 1.90, 3.24), age ≥ 65 years (aOR 1.37; 95% CI 1.10, 1.71), Charlson comorbidity index ≥ 3 (aOR 1.27; 95% CI 1.04, 1.55), immunosuppressive therapy (aOR 1.21; 95% CI 1.02, 1.42), and inflammatory bowel disease (aOR 1.56; 95% CI 1.13, 2.17) were associated with being prescribed guideline-adherent therapy. CONCLUSIONS: Provider adherence to the 2010 treatment guidelines for severe CDI was low. Although the updated 2017 CDI guidelines, which expand the use of oral vancomycin for all CDI, might improve adherence by removing the need to apply severity criteria, other efforts to improve adherence are likely needed, including educating providers and addressing barriers to prescribing guideline-adherent therapy, particularly in outpatient settings.

Toxin Enzyme Immunoassays Detect Clostridioides difficile Infection With Greater Severity and Higher Recurrence Rates.

BACKGROUND: Few data suggest that Clostridioides difficile infections (CDIs) detected by toxin enzyme immunoassay (EIA) are more severe and have worse outcomes than those detected by nucleic acid amplification tests (NAATs) only. We compared toxin- positive and NAAT-positive-only CDI across geographically diverse sites. METHODS: A case was defined as a positive C. difficile test in a person ≥1 year old with no positive tests in the prior 8 weeks. Cases were detected during 2014-2015 by a testing algorithm (specimens initially tested by glutamate dehydrogenase and toxin EIA; if discordant results, specimens were reflexed to NAAT) and classified as toxin positive or NAAT positive only. Medical charts were reviewed. Multivariable logistic regression models were used to compare CDI-related complications, recurrence, and 30-day mortality between the 2 groups. RESULTS: Of 4878 cases, 2160 (44.3%) were toxin positive and 2718 (55.7%) were NAAT positive only. More toxin-positive than NAAT-positive-only cases were aged ≥65 years (48.2% vs 38.0%; P < .0001), had ≥3 unformed stools for ≥1 day (43.9% vs 36.6%; P < .0001), and had white blood cell counts ≥15 000 cells/µL (31.4% vs 21.4%; P < .0001). In multivariable analysis, toxin positivity was associated with recurrence (adjusted odds ratio [aOR], 1.89; 95% confidence interval [CI], 1.61-2.23), but not with CDI-related complications (aOR, 0.91; 95% CI, .67-1.23) or 30-day mortality (aOR, 0.95; 95% CI, .73-1.24). CONCLUSIONS: Toxin-positive CDI is more severe, but there were no differences in adjusted CDI-related complication and mortality rates between toxin-positive and NAAT-positive-only CDI that were detected by an algorithm that utilized an initial glutamate dehydrogenase screening test.

Health care worker perceptions toward computerized clinical decision support tools for Clostridium difficile infection reduction: A qualitative study at 2 hospitals.

BACKGROUND: Clostridium difficile infection (CDI) is associated with significant morbidity and mortality. Computerized clinical decision support (CCDS) tools can aid process improvement in infection prevention and antibiotic stewardship, but implementation and health care workers (HCWs) uptake of these tools is often variable. The objective of this study was to describe HCWs' perceptions of barriers and facilitators related to uptake of CCDS tools as part of a CDI reduction bundle. METHODS: We conducted a qualitative study among HCWs at 2 acute care hospitals in Maryland. Semi-structured interviews and structured surveys were completed by HCWs to evaluate their perception to CCDS tools at 2 different stages: predevelopment and preimplementation. Emergent themes and patterns in the data were identified and condensed. RESULTS: Gaps in CDI-related knowledge and in communication between HCWs were identified throughout the evaluation. HCWs agreed on the potential of the tools to improve CDI diagnosis, prevention, and control. An important barrier for uptake was the perceived loss of autonomy and clinical judgment, whereas standardization and error reduction were perceived advantages. CONCLUSIONS: These observations shaped the development and implementation of the CDI reduction bundle. Qualitative findings can provide valuable contextual information during the development stages of CCDS tools in infection prevention and antibiotic stewardship.

Risk Factors for Community-Associated Clostridium difficile Infection in Adults: A Case-Control Study.

BACKGROUND: An increasing proportion of Clostridium difficile infections (CDI) in the United States are community-associated (CA). We conducted a case-control study to identify CA-CDI risk factors. METHODS: We enrolled participants from 10 US sites during October 2014-March 2015. Case patients were defined as persons age ≥18 years with a positive C. difficile specimen collected as an outpatient or within 3 days of hospitalization who had no admission to a health care facility in the prior 12 weeks and no prior CDI diagnosis. Each case patient was matched to one control (persons without CDI). Participants were interviewed about relevant exposures; multivariate conditional logistic regression was performed. RESULTS: Of 226 pairs, 70.4% were female and 52.2% were ≥60 years old. More case patients than controls had prior outpatient health care (82.1% vs 57.9%; P < .0001) and antibiotic (62.2% vs 10.3%; P < .0001) exposures. In multivariate analysis, antibiotic exposure-that is, cephalosporin (adjusted matched odds ratio [AmOR], 19.02; 95% CI, 1.13-321.39), clindamycin (AmOR, 35.31; 95% CI, 4.01-311.14), fluoroquinolone (AmOR, 30.71; 95% CI, 2.77-340.05) and beta-lactam and/or beta-lactamase inhibitor combination (AmOR, 9.87; 95% CI, 2.76-340.05),-emergency department visit (AmOR, 17.37; 95% CI, 1.99-151.22), white race (AmOR 7.67; 95% CI, 2.34-25.20), cardiac disease (AmOR, 4.87; 95% CI, 1.20-19.80), chronic kidney disease (AmOR, 12.12; 95% CI, 1.24-118.89), and inflammatory bowel disease (AmOR, 5.13; 95% CI, 1.27-20.79) were associated with CA-CDI. CONCLUSIONS: Antibiotics remain an important risk factor for CA-CDI, underscoring the importance of appropriate outpatient prescribing. Emergency departments might be an environmental source of CDI; further investigation of their contribution to CDI transmission is needed.

Burden of Nursing Home-Onset Clostridium difficile Infection in the United States: Estimates of Incidence and Patient Outcomes.

Background. Approximately 4 million Americans receive nursing home (NH) care annually. Nursing home residents commonly have risk factors for Clostridium difficile infection (CDI), including advanced age and antibiotic exposures. We estimated national incidence of NH-onset (NHO) CDI and patient outcomes. Methods. We identified NHO-CDI cases from population-based surveillance of 10 geographic areas in the United States. Cases were defined by C difficile-positive stool collected in an NH (or from NH residents in outpatient settings or ≤3 days after hospital admission) without a positive stool in the prior 8 weeks. Medical records were reviewed on a sample of cases. Incidence was estimated using regression models accounting for age and laboratory testing method; sampling weights were applied to estimate hospitalizations, recurrences, and deaths. Results. A total of 3503 NHO-CDI cases were identified. Among 262 sampled cases, median age was 82 years, 76% received antibiotics in the 12 weeks prior to the C difficile-positive specimen, and 57% were discharged from a hospital in the month before specimen collection. After adjusting for age and testing method, the 2012 national estimate for NHO-CDI incidence was 112 800 cases (95% confidence interval [CI], 93 400-131 800); 31 400 (28%) were hospitalized within 7 days after a positive specimen (95% CI, 25 500-37 300), 20 900 (19%) recurred within 14-60 days (95% CI, 14 600-27 100), and 8700 (8%) died within 30 days (95% CI, 6600-10 700). Conclusions. Nursing home onset CDI is associated with substantial morbidity and mortality. Strategies focused on infection prevention in NHs and appropriate antibiotic use in both NHs and acute care settings may decrease the burden of NHO CDI.

NAP1 strain type predicts outcomes from Clostridium difficile infection.

BACKGROUND: Studies are conflicting regarding the importance of the fluoroquinolone-resistant North American pulsed-field gel electrophoresis type 1 (NAP1) strain in Clostridium difficile infection (CDI) outcome. We describe strain types causing CDI and evaluate their association with patient outcomes. METHODS: CDI cases were identified from population-based surveillance. Multivariate regression models were used to evaluate the associations of strain type with severe disease (ileus, toxic megacolon, or pseudomembranous colitis within 5 days; or white blood cell count ≥15 000 cells/µL within 1 day of positive test), severe outcome (intensive care unit admission after positive test, colectomy for C. difficile infection, or death within 30 days of positive test), and death within 14 days of positive test. RESULTS: Strain typing results were available for 2057 cases. Severe disease occurred in 363 (17.7%) cases, severe outcome in 100 (4.9%), and death within 14 days in 56 (2.7%). The most common strain types were NAP1 (28.4%), NAP4 (10.2%), and NAP11 (9.1%). In unadjusted analysis, NAP1 was associated with greater odds of severe disease than other strains. After controlling for patient risk factors, healthcare exposure, and antibiotic use, NAP1 was associated with severe disease (adjusted odds ratio [AOR], 1.74; 95% confidence interval [CI], 1.36-2.22), severe outcome (AOR, 1.66; 95% CI, 1.09-2.54), and death within 14 days (AOR, 2.12; 95% CI, 1.22-3.68). CONCLUSIONS: NAP1 was the most prevalent strain and a predictor of severe disease, severe outcome, and death. Strategies to reduce NAP1 prevalence, such as antibiotic stewardship to reduce fluoroquinolone use, might reduce CDI morbidity.