A time-series analysis of clostridium difficile and its seasonal association with influenza

Effectiveness of Bio-K+ for the prevention of Clostridioides difficile infection: Stepped-wedge cluster-randomized controlled trial

OBJECTIVE

To evaluate the impact of administering probiotics to prevent Clostridioides difficile infection (CDI) among patients receiving therapeutic antibiotics.

DESIGN

Stepped-wedge cluster-randomized trial between September 1, 2016, and August 31, 2019.

SETTING

This study was conducted in 4 acute-care hospitals across an integrated health region.

PATIENTS

Hospitalized patients, aged ≥55 years.

METHODS

Patients were given 2 probiotic capsules daily (Bio-K+, Laval, Quebec, Canada), containing 50 billion colony-forming units of Lactobacillus acidophilus CL1285, L. casei LBC80R, and L. rhamnosus CLR2. We measured hospital-acquired CDI (HA-CDI) and the number of positive C. difficile tests per 10,000 patient days as well as adherence to administration of Bio-K+ within 48 and 72 hours of antibiotic administration. Mixed-effects generalized linear models, adjusted for influenza admissions and facility characteristics, were used to evaluate the impact of the intervention on outcomes.

RESULTS

Overall adherence of Bio-K+ administration ranged from 76.9% to 84.6% when stratified by facility and periods. Rates of adherence to administration within 48 and 72 hours of antibiotic treatment were 60.2% -71.4% and 66.7%-75.8%, respectively. In the adjusted analysis, there was no change in HA-CDI (incidence rate ratio [IRR], 0.92; 95% confidence interval [CI], 0.68-1.23) or C. difficile positivity rate (IRR, 1.05; 95% CI, 0.89-1.24). Discharged patients may not have received a complete course of Bio-K+. Our hospitals had a low baseline incidence of HA-CDI. Patients who did not receive Bio-K+ may have differential risks of acquiring CDI, introducing selection bias.

CONCLUSIONS

Hospitals considering probiotics as a primary prevention strategy should consider the baseline incidence of HA-CDI in their population and timing of probiotics relative to the start of antimicrobial administration.

Impact of the COVID-19 pandemic on the incidence of healthcare-associated Clostridioides difficile infection in a tertiary healthcare facility in the Republic of Ireland

BACKGROUND

Clostridioides difficile is the foremost cause of nosocomial infectious diarrhoea and one of the most prevalent healthcare associated infections (HAIs).

AIMS

To investigate the impact of the coronavirus disease 2019 (COVID-19) pandemic on the incidence of healthcare associated C. difficile infection (HA-CDI).

METHODS

A retrospective study was conducted from January 2019-December 2022 inclusive at a tertiary University Hospital in Dublin, Ireland. The study period was divided into COVID-19 and non-COVID-19 periods determined in tangent with the then national incidences of COVID-19 and number of hospitalized patients with COVID-19. Analyses looked at quantity of testing performed, incidence rates and antimicrobial consumption. An independent samples t-test was used to determine significance between groups.

RESULTS

Between COVID-19 and non-COVID-19 periods, no statistically significant difference was observed among HA-CDI rates per 10,000 bed-days (2.1 cases vs 1.76 cases; P=0.34), consumption of defined daily doses per 100 bed-days of antimicrobials - all antimicrobials (83.36 vs 89.5; P=0.091), fluoroquinolones only (3.71 vs 4.46; P=0.067), third-generation cephalosporins only (4.17 vs 4.43; P=0.449), carbapenems only (3.28 vs 3.26; P=0.944) - or the number of C. difficile tests performed per 10,000 bed-days (321.81 tests vs 326.63 tests; P=0.696).

CONCLUSIONS

There was no difference in the incidence rates of HA-CDI between COVID-19 and non-COVID-19 periods at our institution.

Impact of Access to Breast Care For West Texas Program on Early Detection and Regional Breast Cancer Mortality

INTRODUCTION

This study aimed to assess whether the Access to Breast Care for West Texas (ABC4WT) program impacted regional breast cancer detection and mortality in the Texas Council of Governments (COG)1 region.

METHODS

Interrupted time series analyses were utilized to evaluate the impact of the intervention. Spearman's rank correlation and cross-orrelation analyses were performed to assess the relationship between the total number of screenings and (i) the total number of breast cancer detected and (ii) the proportion of early-stage cancer detected and the (pre-whitened) residuals. A three-way interaction model compared pre-and post-intervention mortality in COG 1 with the COG 9 region (control).

RESULTS

Increased screening rate was associated with increased breast and early-stage cancer incidences (P = .001 and P = .002, respectively). There were significant positive cross-correlations between the total number of screenings and the total number of breast cancer detected (r = .996) and the proportion of early-stage cancer detected (r = .709) without a lag even after pre-whitening. Univariate analysis showed that regional mortality decreased with time (P < .001) and after intervention (P = .001). Multivariate analysis did not show any significant difference in time (P = .594), intervention (P = .453), and time and intervention interaction (P = .273). The three-way interaction model showed no difference in the baseline mortality and pre-intervention trend difference in COG 1 and COG 9 regions. However, there was a significant pre-post intervention trend difference in mortality COG 1 compared to the COG 9 region (P = .041).

CONCLUSION

Implementing the ABC4WT program was associated with the early detection of breast cancer and reducing regional mortality in the COG 1 region.

Candida gut colonization, yeast species distribution, and biofilm production in Clostridioides difficile infected patients: a comparison between three populations in two different time periods

Candida gut colonization and yeast biofilm production capacity were investigated, by means of XTT reduction assay, in Clostridioides difficile infected (CDI) patients, in non-CDI diarrheic patients, and in healthy donors in two different time periods (2013-2015 and 2018-2019 respectively). Candida gut colonization was significantly (p < 0.001) associated to C. difficile infection, and to patients infected with hypervirulent C. difficile strains bearing the tcdC deletion at nucleotide 117 (p = 0.0003). Although there was not a prevalent yeast species in CDI patients, C. albicans was the species significantly (p < 0.001) associated to both the infections sustained by the non-hypervirulent C. difficile strains and those caused by the hypervirulent strain (p = 0.001). The biofilm production by the yeasts isolated from the CDI patients and from non-CDI diarrheic patients did not differ significantly. However, a significantly (p = 0.007) higher biofilm production was observed in the Candida strains, particularly C. albicans, isolated from healthy donors compared to that of the yeasts cultured from CDI patients. Seasonal occurrence was observed in the isolation rate of CDI and non-CDI diarrheic cases (p = 0.0019), peaking in winter for CDI patients and in spring for non-CDI diarrheic patients. Furthermore, seasonality emerged in the gut colonization by Candida of CDI patients in the winter. It seems, therefore, that the reduced capacity of biofilm production by Candida strains isolated from CDI patients might have a role in the development of C. difficile infection, probably facilitating the spread of the bacteria into the gut thus amplifying their pathogenic action.

Risk for Clostridioides difficile Infection Among Hospitalized Patients Associated With Multiple Healthcare Exposures Prior to Admission

BACKGROUND

Clostridioides difficile infection (CDI) is a common healthcare-associated infection and is often used as an indicator of hospital safety or quality. However, healthcare exposures occurring prior to hospitalization may increase risk for CDI. We conducted a case-control study comparing hospitalized patients with and without CDI to determine if healthcare exposures prior to hospitalization (ie, clinic visits, antibiotics, family members with CDI) were associated with increased risk for hospital-onset CDI, and how risk varied with time between exposure and hospitalization.

METHODS

Records were collected from a large insurance-claims database from 2001 to 2017 for hospitalized adult patients. Prior healthcare exposures were identified using inpatient, outpatient, emergency department, and prescription drug claims; results were compared between various CDI case definitions.

RESULTS

Hospitalized patients with CDI had significantly more frequent healthcare exposures prior to admission. Healthcare visits, antibiotic use, and family exposures were associated with greater likelihood of CDI during hospitalization. The degree of association diminished with time between exposure and hospitalization. Results were consistent across CDI case definitions.

CONCLUSIONS

Many different prior healthcare exposures appear to increase risk for CDI presenting during hospitalization. Moreover, patients with CDI typically have multiple exposures prior to admission, confounding the ability to attribute cases to a particular stay.

Potential Roles for Probiotics in the Treatment of COVID-19 Patients and Prevention of Complications Associated with Increased Antibiotic Use

Medical care for patients hospitalized with COVID-19 is an evolving process. Most COVID-19 inpatients (58-95%) received empiric antibiotics to prevent the increased mortality due to ventilator-associated pneumonia and other secondary infections observed in COVID-19 patients. The expected consequences of increased antibiotic use include antibiotic-associated diarrhea (AAD) and Clostridioides difficile infections (CDI). We reviewed the literature (January 2020-March 2021) to explore strategies to reduce these consequences. Antimicrobial stewardship programs were effective in controlling antibiotic use during past influenza epidemics and have also been shown to reduce healthcare-associated rates of CDI. Another potential strategy is the use of specific strains of probiotics shown to be effective for the prevention of AAD and CDI prior to the pandemic. During 2020, there was a paucity of published trials using these two strategies in COVID-19 patients, but trials are currently ongoing. A multi-strain probiotic mixture was found to be effective in reducing COVID-19-associated diarrhea in one trial. These strategies are promising but need further evidence from trials in COVID-19 patients.

The disease burden of influenza beyond respiratory illness

Although influenza is primarily considered a respiratory infection and causes significant respiratory mortality, evidence suggests that influenza has an additional burden due to broader consequences of the illness. Some of these broader consequences include cardiovascular events, exacerbations of chronic underlying conditions, increased susceptibility to secondary bacterial infections, functional decline, and poor pregnancy outcomes, all of which may lead to an increased risk for hospitalization and death. Although it is methodologically difficult to measure these impacts, epidemiological and interventional study designs have evolved over recent decades to better take them into account. Recognizing these broader consequences of influenza virus infection is essential to determine the full burden of influenza among different subpopulations and the value of preventive approaches. In this review, we outline the main influenza complications and societal impacts beyond the classical respiratory symptoms of the disease.

Clostridioides (Clostridium) difficile-associated disease: Epidemiology among patients in a general hospital in Saudi Arabia

BACKGROUND

Clostridioides (Clostridium) difficile infection (CDI) is an important health care-associated infection with variable incidence and prevalence across the globe. There are limited data from Saudi Arabia on the epidemiology of C. difficile-associated diarrhea (CDAD). In this study, we present the epidemiology and incidence of CDAD in a hospital in Saudi Arabia.

METHODS

This study included all stool samples from 2001 to 2018 that were tested for C. difficile. C. difficile toxins were detected by enzyme-linked immunosorbent assay in 2001-2012 and the diagnosis was based on PCR testing (2013-2018).

RESULTS

There was a total of 577 distinctive episodes of CDAD representing 5.2% of 10,995 tested stool samples with an annual positivity rate of 0.9%-11.8%. Of all CDAD cases, there were 230 (39.9%) community associated-CDAD, 105 (18.2%) community onset-health care facility associated disease, and 242 (42%) health care facility onset health care facility-associated disease (HCFO-HCFAD). There was a trend of increasing percentage of community onset-health care facility associated disease cases from 17% in 2001 to 20% in 2018 of all cases, and a trend towards less cases of community associated-CDAD from 85% to 50% over time. However, the percentages of HCFO-HCFAD percentages remained relatively stable. The rate of HCFO-HCFAD per 1,000 patient-days increased from 0.009 to 0.22 from 2001 to 2018, respectively.

CONCLUSIONS

The rate of CDAD was 5.15% among all tested samples and that there is a large proportion of community associated-CDAD. The findings parallel the data from developed countries and deserve further studies in the risk factors for community-associated CDAD.

Warmer Weather and the Risk of Urinary Tract Infections in Women

PURPOSE

The incidence of urinary tract infections is seasonal, peaking in summer months. One possible mechanism for the observed seasonality of urinary tract infections is warmer weather.

MATERIALS AND METHODS

We identified all urinary tract infection cases located in approximately 400 metropolitan statistical areas in the contiguous United States between 2001 and 2015 using the Truven Health MarketScan® databases. A total of 167,078,882 person-years were included in this data set and a total of 15,876,030 urinary tract infection events were identified by ICD-9 code 599.0. Weather data for each metropolitan statistical area and date were obtained from the National Centers for Environmental Information. We computed the mean temperature during the period 0 to 7 days prior to the urinary tract infection diagnosis. We used a quasi-Poisson generalized linear model. The primary outcome was the number of urinary tract infections each day in a metropolitan statistical area in each age group. Covariates considered included age group, day of week, year and the temperature during the previous 7 days.

RESULTS

Warmer weather increases the risk of urinary tract infections among women treated in outpatient settings in a dose-response fashion. On days when the prior week's average temperature was between 25 and 30C, the incidence of urinary tract infections was increased by 20% to 30% relative to when the prior week's temperature was 5 to 7.5C.

CONCLUSIONS

The incidence of urinary tract infections increases with the prior week's temperature. Our results indicate that warmer weather is a risk factor for urinary tract infections. Furthermore, as temperatures rise, the morbidity attributable to urinary tract infections may increase.

Challenges for Clinical Development of Vaccines for Prevention of Hospital-Acquired Bacterial Infections

Increasing antibiotic resistance in bacteria causing endogenous infections has entailed a need for innovative approaches to therapy and prophylaxis of these infections and raised a new interest in vaccines for prevention of colonization and infection by typically antibiotic resistant pathogens. Nevertheless, there has been a long history of failures in late stage clinical development of this type of vaccines, which remains not fully understood. This article provides an overview on present and past vaccine developments targeting nosocomial bacterial pathogens; it further highlights the specific challenges associated with demonstrating clinical efficacy of these vaccines and the facts to be considered in future study designs. Notably, these vaccines are mainly applied to subjects with preexistent immunity to the target pathogen, transient or chronic immunosuppression and ill-defined microbiome status. Unpredictable attack rates and changing epidemiology as well as highly variable genetic and immunological strain characteristics complicate the development. In views of the clinical need, re-thinking of the study designs and expectations seems warranted: first of all, vaccine development needs to be footed on a clear rationale for choosing the immunological mechanism of action and the optimal time point for vaccination, e.g., (1) prevention (or reduction) of colonization vs. prevention of infection and (2) boosting of a preexistent immune response vs. altering the quality of the immune response. Furthermore, there are different, probably redundant, immunological and microbiological defense mechanisms that provide protection from infection. Their interplay is not well-understood but as a consequence their effect might superimpose vaccine-mediated resolution of infection and lead to failure to demonstrate efficacy. This implies that improved characterization of patient subpopulations within the trial population should be obtained by pro- and retrospective analyses of trial data on subject level. Statistical and systems biology approaches could help to define immune and microbiological biomarkers that discern populations that benefit from vaccination from those where vaccines might not be effective.

Association of Household Exposure to Primary Clostridioides difficile Infection With Secondary Infection in Family Members

Importance

Clostridioides difficile infection (CDI) is a common hospital-acquired infection. Whether family members are more likely to experience a CDI following CDI in another separate family member remains to be studied.

Objective

To determine the incidence of potential family transmission of CDI.

Design, Setting, and Participants

In this case-control study comparing the incidence of CDI among individuals with prior exposure to a family member with CDI to those without prior family exposure, individuals were binned into monthly enrollment strata based on exposure status (eg, family exposure) and confounding factors (eg, age, prior antibiotic use). Data were derived from population-based, longitudinal commercial insurance claims from the Truven Marketscan Commercial Claims and Encounters and Medicare Supplemental databases from 2001 to 2017. Households with at least 2 family members continuously enrolled for at least 1 month were eligible. CDI incidence was computed within each stratum. A regression model was used to compare incidence of CDI while controlling for possible confounding characteristics.

Exposures

Index CDI cases were identified using inpatient and outpatient diagnosis codes. Exposure risks 60 days prior to infection included CDI diagnosed in another family member, prior hospitalization, and antibiotic use.

Main Outcomes and Measures

The primary outcome was the incidence of CDI in a given monthly enrollment stratum. Separate analyses were considered for CDI diagnosed in outpatient or hospital settings.

Results

A total of 224 818 cases of CDI, representing 194 424 enrollees (55.9% female; mean [SD] age, 52.8 [22.2] years) occurred in families with at least 2 enrollees. Of these, 1074 CDI events (4.8%) occurred following CDI diagnosis in a separate family member. Prior family exposure was significantly associated with increased incidence of CDI, with an incidence rate ratio (IRR) of 12.47 (95% CI, 8.86-16.97); this prior family exposure represented the factor with the second highest IRR behind hospital exposure (IRR, 16.18 [95% CI, 15.31-17.10]). For community-onset CDI cases without prior hospitalization, the IRR for family exposure was 21.74 (95% CI, 15.12-30.01). Age (IRR, 9.90 [95% CI, 8.92-10.98] for ages ≥65 years compared with ages 0-17 years), antibiotic use (IRR, 3.73 [95% CI, 3.41-4.08] for low-risk and 14.26 [95% CI, 13.27-15.31] for high-risk antibiotics compared with no antibiotics), and female sex (IRR, 1.44 [95% CI, 1.36-1.53]) were also positively associated with incidence.

Conclusions and Relevance

This study found that individuals with family exposure may be at significantly greater risk for acquiring CDI, which highlights the importance of the shared environment in the transmission and acquisition of C difficile.

Spatiotemporal clustering of in-hospital Clostridioides difficile infection

OBJECTIVE

To determine whether Clostridioides difficile infection (CDI) exhibits spatiotemporal interaction and clustering.

DESIGN

Retrospective observational study.

SETTING

The University of Iowa Hospitals and Clinics.

PATIENTS

This study included 1,963 CDI cases, January 2005 through December 2011.

METHODS

We extracted location and time information for each case and ran the Knox, Mantel, and mean and maximum component size tests for time thresholds (T = 7, 14, and 21 days) and distance thresholds (D = 2, 3, 4, and 5 units; 1 unit = 5-6 m). All tests were implemented using Monte Carlo simulations, and random CDI cases were constructed by randomly permuting times of CDI cases 20,000 times. As a counterfactual, we repeated all tests on 790 aspiration pneumonia cases because aspiration pneumonia is a complication without environmental factors.

RESULTS

Results from the Knox test and mean component size test rejected the null hypothesis of no spatiotemporal interaction (P < .0001), for all values of T and D. Results from the Mantel test also rejected the hypothesis of no spatiotemporal interaction (P < .0003). The same tests showed no such effects for aspiration pneumonia. Our results from the maximum component size tests showed similar trends, but they were not consistently significant, possibly because CDI outbreaks attributable to the environment were relatively small.

CONCLUSION

Our results clearly show spatiotemporal interaction and clustering among CDI cases and none whatsoever for aspiration pneumonia cases. These results strongly suggest that environmental factors play a role in the onset of some CDI cases. However, our results are not inconsistent with the possibility that many genetically unrelated CDI cases occurred during the study period.

Temporal trends of inpatient C. difficile infections within the Veterans Health Administration hospitals: An analysis of the effect of molecular testing, time to testing, and mandatory reporting

BACKGROUND

Clostridium difficile infection (CDI) is a reportable hospital metric associated with significant healthcare expenditures. The epidemiology of CDI is pivotal to the implementation of preventative measures.

OBJECTIVE

To portray temporal CDI trends in Veterans Health Administration (VA) hospitals.

DESIGN

A retrospective analysis of veterans who had stool testing for C. difficile.

SETTING

VA acute-care hospitals within the continental United States.

METHODS

Data were mined from the VA's Corporate Data Warehouse. CDI is reported per 10,000 patient days.

RESULTS

From 2006 to 2016, 472,346 patients had C. difficile testing. Overall, decreases in incidence of total CDI (16.81 to 13.66) and hospital-onset healthcare facility-associated (HO-HCFA) CDI (10.87 to 6.41) were observed. Temporal increases in the incidence of total and HO-HCFA CDI were associated with the increased use of molecular testing (P < .0001). Decreased use of fluoroquinolones (P < .0001), clindamycin (P = .0006), and third-generation cephalosporins (P = .0002) correlated with decreased rates of CDI, but VA mandatory reporting did not influence CDI rates (P = .24). The overall crude 30-day mortality of patients with CDI decreased from 2.17 deaths per 10,000 patient days in 2006 to 1.41 in 2016. The frequency of International Classification of Disease, Ninth/Tenth Revision (ICD-9/10) discharge diagnosis for CDI was 73.3%.

CONCLUSION

Molecular testing was associated with increased incidence of CDI. Controlling CDI is likely multifactorial. Although the VA initiative to report cases of hospital-acquired CDI was not significant in our model, the advent of stewardship programs throughout the VA and reductions in the use of third-generation cephalosporins, fluoroquinolones, and clindamycin were significantly associated with reduced rates of CDI.

Seasonality of respiratory viruses and bacterial pathogens

Background

Seasonal variation has been observed for various bacterial and viral infections. We aimed to further study seasonality of respiratory viruses and bacterial pathogens in relation to antibiotic use, as well as meteorological parameters.

Methods

An ecologic study of antibiotic exposure, meteorological parameters, detection of respiratory viruses  and clinical isolates of Clostridioides difficile, Methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pneumoniae, and Escherichia coli and Klebsiella pneumoniae (grouped together as gram-negative bacteria; GNB) in Rhode Island from 2012 to 2016.

Results

Peak detection of C. difficile occurred 3 months after the peak in antibiotic prescriptions filled (OR = 1.24, 95% CI, 1.07–1.43; P = 0.006). Peak MRSA detection was noted 7 months after the peak in antibiotic prescriptions filled (OR = 1.69, 95% CI, 1.21–2.35; P = 0.003) and 10 months after the peak in respiratory virus detection (OR = 1.04, 95% CI, 1.01–1.06; P = 0.003). Peak GNB detection was noted 2 months after the peak mean monthly ambient temperature (OR = 1.69, 95% C.I., 1.20–2.39; P = 0.004). Peak detection of S. pneumoniae was noted at the same time as the peak in detection of respiratory viruses (OR = 1.01, 95% C.I., 1.00–1.01; P = 0.015).

Conclusions

We identified distinct seasonal variation in detection of respiratory viruses and bacterial pathogens. C. difficile seasonality may, in part, be related to antibiotic prescriptions filled; GNB seasonality may be related to ambient temperature and S. pneumoniae may be related to concurrent respiratory viral infections.

Electronic supplementary material

The online version of this article (10.1186/s13756-019-0574-7) contains supplementary material, which is available to authorized users.

Warmer Weather as a Risk Factor for Cellulitis: A Population-based Investigation

Background

The incidence of cellulitis is highly seasonal and this seasonality may be explained by changes in the weather, specifically, temperature.

Methods

Using data from the Nationwide Inpatient Sample (years 1998 to 2011), we identified the geographic location for 773719 admissions with the primary diagnosis (ICD-9-CM code) of cellulitis and abscess of finger and toe (681.XX) and other cellulitis and abscess (682.XX). Next, we used data from the National Climatic Data Center to estimate the monthly average temperature for each of these different locations. We modeled the odds of an admission having a primary diagnosis of cellulitis as a function of demographics, payer, location, patient severity, admission month, year, and the average temperature in the month of admission.

Results

We found that the odds of an admission with a primary diagnosis of cellulitis increase with higher temperatures in a dose-response fashion. For example, relative to a cold February with average temperatures under 40° F, an admission in a hot July with an average temperature exceeding 90°F has 66.63% higher odds of being diagnosed with cellulitis (95% confidence interval [CI]: [61.2, 72.3]). After controlling for temperature, the estimated amplitude of seasonality of cellulitis decreased by approximately 71%.

Conclusion

At a population level, admissions to the hospital for cellulitis risk are strongly associated with warmer weather.

Seasonality and community interventions in a mathematical model of Clostridium difficile transmission

BACKGROUND

Clostridium difficile infection (CDI) is the leading cause of antibiotic-associated diarrhoea with peak incidence in late winter or early autumn. Although CDI is commonly associated with hospitals, community transmission is important.

AIM

To explore potential drivers of CDI seasonality and the effect of community-based interventions to reduce transmission.

METHODS

A mechanistic compartmental model of C. difficile transmission in a hospital and surrounding community was used to determine the effect of reducing transmission or antibiotic prescriptions in these settings. The model was extended to allow for seasonal antibiotic prescriptions and seasonal transmission.

FINDINGS

Modelling antibiotic seasonality reproduced the seasonality of CDI, including approximate magnitude (13.9-15.1% above annual mean) and timing of peaks (0.7-1.0 months after peak antibiotics). Halving seasonal excess prescriptions reduced the incidence of CDI by 6-18%. Seasonal transmission produced larger seasonal peaks in the prevalence of community colonization (14.8-22.1% above mean) than seasonal antibiotic prescriptions (0.2-1.7% above mean). Reducing transmission from symptomatic or hospitalized patients had little effect on community-acquired CDI, but reducing transmission in the community by ≥7% or transmission from infants by ≥30% eliminated the pathogen. Reducing antibiotic prescription rates led to approximately proportional reductions in infections, but limited reductions in the prevalence of colonization.

CONCLUSION

Seasonal variation in antibiotic prescription rates can account for the observed magnitude and timing of C. difficile seasonality. Even complete prevention of transmission from hospitalized patients or symptomatic patients cannot eliminate the pathogen, but interventions to reduce transmission from community residents or infants could have a large impact on both hospital- and community-acquired infections.

Genomic Study of a Clostridium difficile Multidrug Resistant Outbreak-Related Clone Reveals Novel Determinants of Resistance

Background:Clostridium difficile infection (CDI) is prevalent in healthcare settings. The emergence of hypervirulent and antibiotic resistant strains has led to an increase in CDI incidence and frequent outbreaks. While the main virulence factors are the TcdA and TcdB toxins, antibiotic resistance is thought to play a key role in the infection by and dissemination of C. difficile.

Methods: A CDI outbreak involving 12 patients was detected in a tertiary care hospital, in Lisbon, which extended from January to July, with a peak in February, in 2016. The C. difficile isolates, obtained from anaerobic culture of stool samples, were subjected to antimicrobial susceptibility testing with Etest^®strips against 11 antibiotics, determination of toxin genes profile, PCR-ribotyping, multilocus variable-number tandem-repeat analysis (MLVA) and whole genome sequencing (WGS).

Results: Of the 12 CDI cases detected, 11 isolates from 11 patients were characterized. All isolates were tcdA^-/tcdB⁺ and belonged to ribotype 017, and showed high level resistance to clindamycin, erythromycin, gentamicin, imipenem, moxifloxacin, rifampicin and tetracycline. The isolates belonged to four genetically related MLVA types, with six isolates forming a clonal cluster. Three outbreak isolates, each from a different MLVA type, were selected for WGS. Bioinformatics analysis showed the presence of several antibiotic resistance determinants, including the Thr82Ile substitution in gyrA, conferring moxifloxacin resistance, the substitutions His502Asn and Arg505Lys in rpoB for rifampicin resistance, the tetM gene, associated with tetracycline resistance, and two genes encoding putative aminoglycoside-modifying enzymes, aadE and aac(6′)-aph(2″). Furthermore, a not previously described 61.3 kb putative mobile element was identified, presenting a mosaic structure and containing the genes ermG, mefA/msrD and vat, associated with macrolide, lincosamide and streptogramins resistance. A substitution found in a class B penicillin-binding protein, Cys721Ser, is thought to contribute to imipenem resistance.

Conclusion: We describe an epidemic, tcdA^-/tcdB⁺, multidrug resistant clone of C. difficile from ribotype 017 associated with a hospital outbreak, providing further evidence that the lack of TcdA does not impair the infectious potential of these strains. We identified several determinants of antimicrobial resistance, including new ones located in mobile elements, highlighting the importance of horizontal gene transfer in the pathogenicity and epidemiological success of C. difficile.

Impact of the introduction of a nucleic acid amplification test for Clostridium difficile diagnosis on stool rejection policies

Background

The change from non-molecular to nucleic acid amplification tests (NAATs) is known to increase the detection of Clostridium difficile infection (CDI); however, the impact on stool rejection policies in clinical laboratories is unclear. The current guidelines have reinforced the importance of respecting strict conditions for performing tests on stool samples for CDI diagnosis. The purpose of this study was to estimate whether the implementation of molecular tests has resulted in changes in stool rejection policies between clinical laboratories that introduced NAATs and those that did not.

Results

A survey was conducted to evaluate the change in the number of stool samples rejected and the rejection criteria among 12 hospital laboratories in southwestern France before and after the switch from non-molecular tests to NAATs using retrospective data from June 1 till September 30, 2013 and the same period 2014. Four laboratories introduced NAATs as a second or third step in the process. A total of 1378 and 1297 stools samples were collected in 2013 and 2014, respectively. The mean number of rejected stool samples significantly increased (p < 0.001, Chi square test), with a total of 99 (7.1%) and 147 (11.3%) specimens rejected in 2013 and 2014, respectively. Notably, these laboratories had more stringent criteria and were no longer testing the stool samples of patients with CDI-positive results within 7 days. In contrast, there was a significant decrease in the rate of rejected stool samples (p < 0.001, Chi square test) in the five laboratories that did not adopt NAATs and a less stringent stool rejection policy.

Conclusion

Nucleic acid amplification test implementation improved compliance with recommended stool rejection policies. Laboratories should follow the recommended laboratory algorithm for the CDI diagnosis combined with the correct stool rejection policy.

Electronic supplementary material

The online version of this article (10.1186/s13099-018-0245-x) contains supplementary material, which is available to authorized users.

The Seasonal Variability of Surgical Site Infections in Knee and Hip Arthroplasty

BACKGROUND

Surgical site infections (SSIs) after total knee (TKA) and total hip (THA) arthroplasty are devastating to patients and costly to healthcare systems. The purpose of this study is to investigate the seasonality of TKA and THA SSIs at a national level.

METHODS

All data were extracted from the National Readmission Database for 2013 and 2014. Patients were included if they had undergone TKA or THA. We modeled the odds of having a primary diagnosis of SSI as a function of discharge date by month, payer status, hospital size, and various patient co-morbidities. SSI status was defined as patients who were readmitted to the hospital with a primary diagnosis of SSI within 30 days of their arthroplasty procedure.

RESULTS

There were 760,283 procedures (TKA 424,104, THA 336,179) in our sample. Our models indicate that SSI risk was highest for patients discharged from their surgery in June and lowest for December discharges. For TKA, the odds of a 30-day readmission for SSI were 30.5% higher at the peak compared to the nadir time (95% confidence interval [CI] 20-42). For THA, the seasonal increase in SSI was 19% (95% CI 9-30). Compared to Medicare, patients with Medicaid as the primary payer had a 49% higher odds of 30-day SSI after TKA (95% CI 32-68).

CONCLUSION

SSIs following TKA and THA are seasonal peaking in summer months. Payer status was also a significant risk factor for SSIs. Future studies should investigate potential factors that could relate to the associations demonstrated in this study.

The Seasonal Variability in Surgical Site Infections and the Association With Warmer Weather: A Population-Based Investigation

OBJECTIVE To determine whether the seasonality of surgical site infections (SSIs) can be explained by changes in temperature. DESIGN Retrospective cohort analysis. SETTING The National Inpatient Sample database. PATIENTS All hospital discharges with a primary diagnosis of SSI from 1998 to 2011 were considered cases. Discharges with a primary or secondary diagnoses of specific surgeries commonly associated with SSIs from the previous and current month served as our "at risk" cohort. METHODS We modeled the national monthly count of SSI cases both nationally and stratified by region, sex, age, and type of institution. We used data from the National Climatic Data Center to estimate the monthly average temperatures for all hospital locations. We modeled the odds of having a primary diagnosis of SSI as a function of demographics, payer, location, patient severity, admission month, year, and the average temperature in the month of admission. RESULTS SSI incidence is highly seasonal, with the highest SSI incidence in August and the lowest in January. During the study period, there were 26.5% more cases in August than in January (95% CI, 23.3-29.7). Controlling for demographic and hospital-level characteristics, the odds of a primary SSI admission increased by roughly 2.1% per 2.8°C (5°F) increase in the average monthly temperature. Specifically, the highest temperature group, >32.2°C (>90°F), was associated with an increase in the odds of an SSI admission of 28.9% (95% CI, 20.2-38.3) compared to temperatures <4.4°C (<40°F). CONCLUSIONS At population level, SSI risk is highly seasonal and is associated with warmer weather. Infect Control Hosp Epidemiol 2017;38:809-816.

Receipt of Antibiotics in Hospitalized Patients and Risk for Clostridium difficile Infection in Subsequent Patients Who Occupy the Same Bed

OBJECTIVE

To assess whether receipt of antibiotics by prior hospital bed occupants is associated with increased risk for CDI in subsequent patients who occupy the same bed.

DESIGN, SETTING, AND PARTICIPANTS

This is a retrospective cohort study of adult patients hospitalized in any 1 of 4 facilities between 2010 and 2015. Patients were excluded if they had recent CDI, developed CDI within 48 hours of admission, had inadequate follow-up time, or if their prior bed occupant was in the bed for less than 24 hours.

MAIN OUTCOMES AND MEASURES

The primary exposure was receipt of non-CDI antibiotics by the prior bed occupant and the primary outcome was incident CDI in the subsequent patient to occupy the same bed. Incident CDI was defined as a positive result from a stool polymerase chain reaction for the C difficile toxin B gene followed by treatment for CDI. Demographics, comorbidities, laboratory data, and medication exposures are reported.

RESULTS

Among 100 615 pairs of patients who sequentially occupied a given hospital bed, there were 576 pairs (0.57%) in which subsequent patients developed CDI. Receipt of antibiotics in prior patients was significantly associated with incident CDI in subsequent patients (log-rank P < .01). This relationship remained unchanged after adjusting for factors known to influence risk for CDI including receipt of antibiotics by the subsequent patient (adjusted hazard ratio [aHR], 1.22; 95% CI, 1.02-1.45) and also after excluding 1497 patient pairs among whom the prior patients developed CDI (aHR, 1.20; 95% CI, 1.01-1.43). Aside from antibiotics, no other factors related to the prior bed occupants were associated with increased risk for CDI in subsequent patients.

CONCLUSIONS AND RELEVANCE

Receipt of antibiotics by prior bed occupants was associated with increased risk for CDI in subsequent patients. Antibiotics can directly affect risk for CDI in patients who do not themselves receive antibiotics.

Clostridium difficile Infections in Medical Intensive Care Units of a Medical Center in Southern Taiwan: Variable Seasonality and Disease Severity

Critical patients are susceptible to Clostridium difficile infections (CDIs), which cause significant morbidity and mortality in the hospital. In Taiwan, the epidemiology of CDI in intensive care units (ICUs) is not well understood. This study was aimed to describe the incidence and the characteristics of CDI in the ICUs of a medical center in southern Taiwan. Adult patients with diarrhea but without colostomy/colectomy or laxative use were enrolled. Stool samples were collected with or without 5 ml alcohol and were plated on cycloserine-cefoxitin-fructose agar. C. difficile identification was confirmed by polymerase chain reaction. There were 1,551 patients admitted to ICUs, 1,488 screened, and 145 with diarrhea. A total of 75 patients were excluded due either to laxative use, a lack of stool samples, or refusal. Overall, 70 patients were included, and 14 (20%) were diagnosed with CDI, with an incidence of 8.8 cases per 10,000 patient-days. The incidence of CDI was found to be highest in March 2013 and lowest in the last quarter of 2013. The cases were categorized as the following: 5 severe, complicated, 5 severe, and 4 mild or moderate diseases. Among the 14 cases of CDI, the median patient age was 74 (range: 47-94) years, and the median time from admission to diarrhea onset was 16.5 (4-53) days. Eight cases received antimicrobial treatment (primarily metronidazole), and the time to diarrheal resolution was 11.5 days. Though 6 cases were left untreated, no patients died of CDI. The in-hospital mortality of CDI cases was 50%, similar to that of patients without CDI (46.4%; P = 1.0). We concluded that the overall incidence of CDI in our medical ICUs was low and there were variable seasonal incidences and disease severities of CDI.

An evaluation of the effectiveness of an algorithm intervention in reducing inappropriate faecal samples sent for Clostridium difficile testing

BACKGROUND

Clostridium difficile (C. difficile) is a leading cause of infectious diarrhoea in hospitals. Sending faecal samples for testing expedites diagnosis and appropriate treatment. Clinical suspicion of C. difficile based on patient history, signs and symptoms is the basis for sampling. Sending faecal samples from patients with diarrhoea 'just in case' the patient has C. difficile may be an indication of poor clinical management.

AIM

To evaluate the effectiveness of an intervention by an Infection Prevention and Control Team (IPCT) in reducing inappropriate faecal samples sent for C. difficile testing.

METHOD

An audit of numbers of faecal samples sent before and after a decision-making algorithm was introduced. The number of samples received in the laboratory was retrospectively counted for 12-week periods before and after an algorithm was introduced.

FINDINGS

There was a statistically significant reduction in the mean number of faecal samples sent post the algorithm. Results were compared to a similar intervention carried out in 2009 in which the same message was delivered by a memorandum. In 2009 the memorandum had no effect on the overall number of weekly samples being sent.

CONCLUSION

An algorithm intervention had an effect on the number of faecal samples being sent for C. difficile testing and thus contributed to the effective use of the laboratory service.

Epidemiology of Clostridium difficile infections in Australia: enhanced surveillance to evaluate time trends and severity of illness in Victoria, 2010-2014

BACKGROUND

With epidemic strains of Clostridium difficile posing a substantial healthcare burden internationally, there is a need for longitudinal evaluation of Clostridium difficile infection (CDI) events in Australia.

AIM

To evaluate time trends and severity of illness for CDI events in Australian healthcare facilities.

METHODS

All CDI events in patients admitted to Victorian public hospitals between 1(st) October 2010 and 31(st) December 2014 were reported to the Victorian Healthcare Associated Infection Surveillance System. CDI was defined as the isolation of a toxin-producing C. difficile organism in a diarrhoeal specimen, and classified as community-associated (CA-CDI) or healthcare-associated (HA-CDI). Severe disease was defined as admission to an intensive care unit, requirement for surgery and/or death due to infection. Time trends were examined using a mixed-effects Poisson regression model, and the Walter and Edward test of seasonality was applied to evaluate potential cyclical patterns.

FINDINGS

In total, 6736 CDI events were reported across 89 healthcare facilities. Of these, 4826 (71.6%) were HA-CDI, corresponding to a rate of 2.49/10,000 occupied bed days (OBDs). The incidence of HA-CDI was highest in the fifth quarter of surveillance (3.6/10,000 OBDs), followed by a reduction. Severe disease was reported in 1.66% of events, with the proportion being significantly higher for CA-CDI compared with HA-CDI (2.21 vs 1.45%, P = 0.03). The highest and lowest incidence of HA-CDI occurred in March and October, respectively.

CONCLUSIONS

A low incidence of HA-CDI was reported in Victoria compared with US/European surveillance reports. Seasonality was evident, together with diminishing HA-CDI rates in 2012-2014. Severe infections were more common in CA-CDI, supporting future enhanced surveillance in community settings.

Substantial variation in hospital rankings after adjusting for hospital-level predictors of publicly-reported hospital-associated Clostridium difficile infection rates

Across 366 California hospitals, we identified hospital-level characteristics predicting increased hospital-associated Clostridium difficile infection (HA-CDI) rates including more licensed beds, teaching and long-term acute care (LTAC) hospitals, and polymerase chain reaction testing. Adjustment for these characteristics impacted rankings in 24% of teaching hospitals, 13% of community hospitals, and 11% of LTAC hospitals.

Regional and seasonal variation in Clostridium difficile infections among hospitalized patients in the United States, 2001-2010

BACKGROUND

This study identified national regional and seasonal variations in Clostridium difficile infection (CDI) incidence and mortality among hospitalized patients in the United States over a 10-year period.

METHODS

This was a retrospective cohort study of the U.S. National Hospital Discharge Survey from 2001-2010. Eligible cases had an ICD-9-CM discharge diagnosis code for CDI (008.45). Data weights were used to derive national estimates. CDI incidence and mortality were presented descriptively. Regions were as defined by the U.S. Census Bureau. Seasons included the following: winter (December-February), spring (March-May), summer (June-August), and fall (September-November).

RESULTS

These data represent 2.3 million CDI discharges. Overall, CDI incidence was highest in the Northeast (8.0 CDIs/1,000 discharges) and spring (6.2 CDIs/1,000 discharges). CDI incidence was lowest in the West (4.8 CDIs/1,000 discharges) and fall (5.6 CDIs/1,000 discharges). Peak CDI incidence among children occurred in the West (1.7 CDI/1,000 discharges) and winter (1.5 CDI/1,000 discharges). Mortality among all CDI patients was highest in the Midwest (7.3%) and during the winter (7.9%).

CONCLUSION

The region and season with the highest CDI incidence rates among patients hospitalized in U.S. hospitals were the Northeast and spring, respectively. The highest CDI mortality rates were seen in the Midwest and winter. Children exhibited different regional and seasonal CDI variations compared with adults and older adults.

Clostridium difficile infection seasonality: patterns across hemispheres and continents - a systematic review

Background

Studies have demonstrated seasonal variability in rates of Clostridium difficile infection (CDI). Synthesising all available information on seasonality is a necessary step in identifying large-scale epidemiological patterns and elucidating underlying causes.

Methods

Three medical and life sciences publication databases were searched from inception to October 2014 for longitudinal epidemiological studies written in English, Spanish or Portuguese that reported the incidence of CDI. The monthly frequency of CDI were extracted, standardized and weighted according to the number of follow-up months. Cross correlation coefficients (XCORR) were calculated to examine the correlation and lag between the year-month frequencies of reported CDI across hemispheres and continents.

Results

The search identified 13, 5 and 2 studies from North America, Europe, and Oceania, respectively that met the inclusion criteria. CDI had a similar seasonal pattern in the Northern and Southern Hemisphere characterized by a peak in spring and lower frequencies of CDI in summer/autumn with a lag of 8 months (XCORR = 0.60) between hemispheres. There was no difference between the seasonal patterns across European and North American countries.

Conclusion

CDI demonstrates a distinct seasonal pattern that is consistent across North America, Europe and Oceania. Further studies are required to identify the driving factors of the observed seasonality.

Emergence and spread of predominantly community-onset Clostridium difficile PCR ribotype 244 infection in Australia, 2010 to 2012

We describe an Australia-wide Clostridium difficile outbreak in 2011 and 2012 involving the previously uncommon ribotype 244. In Western Australia, 14 of 25 cases were community-associated, 11 were detected in patients younger than 65 years, 14 presented to emergency/outpatient departments, and 14 to non-tertiary/community hospitals. Using whole genome sequencing, we confirm ribotype 244 is from the same C. difficile clade as the epidemic ribotype 027. Like ribotype 027, it produces toxins A, B, and binary toxin, however it is fluoroquinolone-susceptible and thousands of single nucleotide variants distinct from ribotype 027. Fifteen outbreak isolates from across Australia were sequenced. Despite their geographic separation, all were genetically highly related without evidence of geographic clustering, consistent with a point source, for example affecting the national food chain. Comparison with reference laboratory strains revealed the outbreak clone shared a common ancestor with isolates from the United States and United Kingdom (UK). A strain obtained in the UK was phylogenetically related to our outbreak. Follow-up of that case revealed the patient had recently returned from Australia. Our data demonstrate new C. difficile strains are an on-going threat, with potential for rapid spread. Active surveillance is needed to identify and control emerging lineages.

Epidemiological Patterns and Hospital Characteristics Associated with Increased Incidence ofClostridium difficileInfection in Quebec, Canada, 1998–2006

Objective.

To explore epidemiological patterns of the incidence ofClostridium difficileinfection (CDI) and hospital characteristics associated with increased incidence during nonepidemic and epidemic years.

Design.

Retrospective and prospective ecological study.

Setting.

Eighty-three acute care hospitals participating in CDI surveillance in the province of Quebec, Canada.

Methods.

A Serfling-type regression model applied to data obtained from an administrative database (1998-2006) and prospective Quebec CDI surveillance (2004-2006) was used to calculate expected CDI baseline incidence and to detect incidence exceeding the defined epidemic threshold at the provincial and hospital level. Multivariable Poisson regression was used to determine hospital characteristics associated with increased incidence during nonepidemic (1998-2001) and epidemic (2003-2005) periods.

Results.

During the study period (1998-2006), 4,525,847 discharges, including 45,508 with a CDI in any diagnosis field, were reported by 83 hospitals. During 1998-2001, the average Quebec incidence of CDI was 10,304 cases in 1,775,822 discharges (5.8 cases per 1,000 discharges) and presented a pattern of seasonality, with similar patterns at the hospital level for some hospitals. The Quebec epidemic started in October-November 2002 and peaked in March 2004 at 845 cases in 40,852 discharges (20.7 cases per 1,000 discharges). In multivariable analysis, higher incidence was associated with location in Montreal and surrounding regions, greater hospital size, larger proportion of hospitalized elderly patients, longer length of stay, and greater proportion of comorbidities in patients, whereas teaching profile was associated with decreased incidence during both nonepidemic and epidemic periods. The effect of geographical location on incidence was greater during the epidemic.

Conclusion.

Baseline incidence from nonepidemic years and hospital characteristics associated with CDI incidence should be taken into account when estimating the efficacy of interventions.

Seasonal and Pandemic Influenza Surveillance and Disease Severity

Continuous investments in influenza research, surveillance, and prevention efforts are critical to mitigate the consequences of annual influenza epidemics and pandemics. New influenza viruses emerge due to antigenic drift and antigenic shift evading human immune system and causing annual epidemics and pandemics. Three pandemics with varying disease severity occurred in the last 100 years. The disease burden and determinants of influenza severity depend on circulating viral strains and individual demographic and clinical factors. Surveillance is the most effective strategy for appropriate public health response. Active and passive surveillance methods are utilized to monitor influenza epidemics and emergence of novel viruses. Meaningful use of electronic health records could be a cost-effective approach to improved influenza surveillance

The magnitude and duration of Clostridium difficile infection risk associated with antibiotic therapy: a hospital cohort study

Antibiotic therapy is the principal risk factor for Clostridium difficile infection (CDI), but little is known about how risks cumulate over the course of therapy and abate after cessation. We prospectively identified CDI cases among adults hospitalized at a tertiary hospital between June 2010 and May 2012. Poisson regression models included covariates for time since admission, age, hospitalization history, disease pressure, and intensive care unit stay. Impacts of antibiotic use through time were modeled using 4 measures: current antibiotic receipt, time since most recent receipt, time since first receipt during a hospitalization, and duration of receipt. Over the 24-month study period, we identified 127 patients with new onset nosocomial CDI (incidence rate per 10,000 patient days [IR] = 5.86). Of the 4 measures, time since most recent receipt was the strongest independent predictor of CDI incidence. Relative to patients with no prior receipt of antibiotics in the last 30 days (IR = 2.95), the incidence rate of CDI was 2.41 times higher (95% confidence interval [CI] 1.41, 4.13) during antibiotic receipt and 2.16 times higher when patients had receipt in the prior 1–5 days (CI 1.17, 4.00). The incidence rates of CDI following 1–3, 4–6 and 7–11 days of antibiotic exposure were 1.60 (CI 0.85, 3.03), 2.27 (CI 1.24, 4.16) and 2.10 (CI 1.12, 3.94) times higher compared to no prior receipt. These findings are consistent with studies showing higher risk associated with longer antibiotic use in hospitalized patients, but suggest that the duration of increased risk is shorter than previously thought.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Nosocomial transmission of C. difficile in English hospitals from patients with symptomatic infection

Background

Recent evidence suggests that less than one-quarter of patients with symptomatic nosocomial Clostridium difficile infections (CDI) are linked to other in-patients. However, this evidence was limited to one geographic area. We aimed to investigate the level of symptomatic CDI transmission in hospitals located across England from 2008 to 2012.

Methods

A generalized additive mixed-effects Poisson model was fitted to English hospital-surveillance data. After adjusting for seasonal fluctuations and between-hospital variation in reported CDI over time, possible clustering (transmission between symptomatic in-patients) of CDI cases was identified. We hypothesised that a temporal proximity would be reflected in the degree of correlation between in-hospital CDI cases per week. This correlation was modelled through a latent autoregressive structure of order 1 (AR(1)).

Findings

Forty-six hospitals (33 general, seven specialist, and six teaching hospitals) located in all English regions met our criteria. In total, 12,717 CDI cases were identified; seventy-five per cent of these occurred >48 hours after admission. There were slight increases in reports during winter months. We found a low, but statistically significant, correlation between successive weekly CDI case incidences (phi = 0.029, 95%CI: 0.009–0.049). This correlation was five times stronger in a subgroup analysis restricted to teaching hospitals (phi = 0.104, 95%CI: 0.048–0.159).

Conclusions

The results suggest that symptomatic patient-to-patient transmission has been a source of CDI-acquisition in English hospitals in recent years, and that this might be a more important transmission route in teaching hospitals. Nonetheless, the weak correlation indicates that, in line with recent evidence, symptomatic cases might not be the primary source of nosocomial CDI in England.

Clostridium difficile surveillance: harnessing new technologies to control transmission

Clostridium difficile surveillance allows outbreaks of cases clustered in time and space to be identified and further transmission prevented. Traditionally, manual detection of groups of cases diagnosed in the same ward or hospital, often followed by retrospective reference laboratory genotyping, has been used to identify outbreaks. However, integrated healthcare databases offer the prospect of automated real-time outbreak detection based on statistically robust methods, and accounting for contacts between cases, including those distant to the ward of diagnosis. Complementary to this, rapid benchtop whole genome sequencing, and other highly discriminatory genotyping, has the potential to distinguish which cases are part of an outbreak with high precision and in clinically relevant timescales. These new technologies are likely to shape future surveillance.

[Clostridium difficile infections in Spanish Internal Medicine departments during the period 2005-2010: the burden of the disease]

INTRODUCTION

Clostridium Difficile infection (CDI) is increasing in Spain. A review is presented of this infection in order to evaluate the burden of the disease in this country.

MATERIAL

An analytical retrospective and descriptive study was conducted by analyzing the Minimum Basic Data Set of patients admitted to Internal Medicine Departments and with and without CDI between the years 2005-2010. Clinical and demographical variables were compared.

RESULTS

Mean age was 75.5 years (SD 15.4), 54.9% were women and mean stay was 22.2 days (SD 24.8). The Cost [(€ 5,001 (SD 4,985) vs [€ 3,934 (SD 2,738)] and diagnostic complexity [2.04 (SD 2.62) vs [1.67 (SD 1.47)] were also different. Mortality for all causes was 12.5% vs 9.8%. Death risk showed a 30% increase (odds ratio 1.30, 95% confidence interval;1.21-1.39) and readmission rate was 30.4% vs 13.5%. Distribution of cases showed season variations (more cases in winter), and annual incidence increased during the study period. Comorbidities associated to increased risk of acquiring CDI were: anemia, human immunodeficiency virus, dementia, malnutrition, chronic renal failure, and living in a nursing home.

CONCLUSION

The results showed a clear negative impact of CDI on hospital admissions. A trend towards progression in its incidence without changes in mortality or readmission rates was observed, in common with the rest of Europe and the Western World.

Spatial and temporal analyses to investigate infectious disease transmission within healthcare settings

Background

Healthcare-associated infections (HCAIs) cause significant morbidity and mortality worldwide, and outbreaks are often only identified after they reach high levels. A wide range of data is collected within healthcare settings; however, the extent to which this information is used to understand HCAI dynamics has not been quantified.

Aim

To examine the use of spatiotemporal analyses to identify and prevent HCAI transmission in healthcare settings, and to provide recommendations for expanding the use of these techniques.

Methods

A systematic review of the literature was undertaken, focusing on spatiotemporal examination of infectious diseases in healthcare settings. Abstracts and full-text articles were reviewed independently by two authors to determine inclusion.

Findings

In total, 146 studies met the inclusion criteria. There was considerable variation in the use of data, with surprisingly few studies (N = 22) using spatiotemporal-specific analyses to extend knowledge of HCAI transmission dynamics. The remaining 124 studies were descriptive. A modest increase in the application of statistical analyses has occurred in recent years.

Conclusion

The incorporation of spatiotemporal analysis has been limited in healthcare settings, with only 15% of studies including any such analysis. Analytical studies provided greater data on transmission dynamics and effective control interventions than studies without spatiotemporal analyses. This indicates the need for greater integration of spatiotemporal techniques into HCAI investigations, as even simple analyses provide significant improvements in the understanding of prevention over simple descriptive summaries.

The identification and epidemiology of meticillin-resistant Staphylococcus aureus and Clostridium difficile in patient rooms and the ward environment

BACKGROUND

Research has indicated that the environment may play an important role in the transmission of meticillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile in healthcare facilities. Despite the significance of this finding, few data exist from longitudinal studies investigating MRSA and C. difficile contamination, concurrently, in both patient rooms and the general ward environment. The objectives of this study were to determine the prevalence of MRSA and C. difficile contamination in patient rooms and the ward environment and identify risk factors associated with a surface being contaminated with these pathogens.

METHODS

Environmental surfaces in patient rooms and the general environment in the medical and surgical wards of a community hospital were sampled six times over a 15 week period. Sterile electrostatic cloths were used for sampling and information pertaining to the surface sampled was recorded. MRSA isolates and C. difficile specimens were obtained from hospitalized patients.Enrichment culture was performed and spa typing or ribotyping was conducted for MRSA or C. difficile, respectively. Exact logistic regression models were constructed to examine risk factors associated with MRSA and C. difficile contamination.

RESULTS

Sixteen (41%) patient rooms had ≥ 1 surfaces contaminated with MRSA and/or C. difficile. For 218 surfaces investigated, 3.2% and 6.4% were contaminated with MRSA or C. difficile, respectively. Regression models indicated that surfaces in rooms exposed to a C. difficile patient had significantly increased odds of being contaminated with C. difficile, compared to surfaces in unexposed patient rooms. Additionally, compared to plastic surfaces, cork surfaces had significantly increased odds of being contaminated with C. difficile. For 236 samples collected from the ward environment, MRSA and C. difficile were recovered from 2.5% and 5.9% of samples, respectively. Overall, the majority of MRSA and C. difficile strains were molecularly identified as spa type 2/t002 (84.6%, n = 11) and ribotype 078 (50%, n = 14), respectively.

CONCLUSIONS

In patient rooms and the ward environment, specific materials and locations were identified as being contaminated with MRSA or C. difficile. These sites should be cleaned and disinfected with increased vigilance to help limit the transmission and dissemination of MRSA and C. difficile within the hospital.

The co-seasonality of pneumonia and influenza with Clostridium difficile infection in the United States, 1993-2008

Seasonal variations in the incidence of pneumonia and influenza are associated with nosocomial Clostridium difficile infection (CDI) incidence, but the reasons why remain unclear. Our objective was to consider the impact of pneumonia and influenza timing and severity on CDI incidence. We conducted a retrospective cohort study using the US National Hospital Discharge Survey sample. Hospitalized patients with a diagnosis of CDI or pneumonia and influenza between 1993 and 2008 were identified from the National Hospital Discharge Survey data set. Poisson regression models of monthly CDI incidence were used to measure 1) the time lag between the annual pneumonia and influenza prevalence peak and the annual CDI incidence peak and 2) the lagged effect of pneumonia and influenza prevalence on CDI incidence. CDI was identified in 18,465 discharges (8.52 per 1,000 discharges). Peak pneumonia prevalence preceded peak CDI incidence by 9.14 weeks (95% confidence interval: 4.61, 13.67). A 1% increase in pneumonia prevalence was associated with a cumulative effect of 11.3% over a 6-month lag period (relative risk = 1.113, 95% confidence interval: 1.073, 1.153). Future research could seek to understand which mediating pathways, including changes in broad-spectrum antibiotic prescribing and hospital crowding, are most responsible for the associated changes in incidence.

Has improved hand hygiene compliance reduced the risk of hospital-acquired infections among hospitalized patients in Ontario? Analysis of publicly reported patient safety data from 2008 to 2011

DESIGN

 Prospective, observational, ecological, time series, cross-sectional study examining the association between hand hygiene compliance (HHC) rates and the incidence of hospital-acquired infections.

SETTING

 Acute care hospitals (N = 166) located in the province of Ontario, Canada.

METHODS

 All data were extracted from the Ontario patient safety indicator database ( http://www.hqontario.ca/public-reporting/patient-safety). Complete data were available for 166 acute care hospitals from October 1, 2008, to December 31, 2011. The rates of Clostridium difficile infection (CDI) are reported monthly, methicillin-resistant Staphylococcus aureus (MRSA) bacteremia quarterly, and HHC rates yearly. Trends and associations for each indicator were evaluated by ordinary least squares regression (HHC), zero-inflated Poisson regression (MRSA bacteremia), or Poisson regression (CDI). Dependent variables included in the regression analyses were extracted from the same database and included year, healthcare region, and type of hospital (teaching or small or large community).

RESULTS

Compared to those in 2008, reported HHC rates improved every year both before and after environment/patient contact (range, 10.6%-25.3%). Compared to those in 2008, there was no corresponding change in the rates of MRSA bacteremia; however, the rates of CDI decreased in 2009 but were not statistically significantly decreased from baseline in either 2010 or 2011. No consistent association was demonstrated between changes in the rates of HHC and these two healthcare-associated infections (HAIs).

CONCLUSIONS

 Despite significant improvements in reported rates of HHC among healthcare personnel in Ontario's hospitals, we could not demonstrate a positive ecological impact on rates of these two HAIs.

Clostridium difficile in foods and animals: history and measures to reduce exposure

Many articles have summarized the changing epidemiology of Clostridium difficile infections (CDI) in humans, but the emerging presence of C. difficile in foods and animals and possible measures to reduce human exposure to this important pathogen have been infrequently addressed. CDIs have traditionally been assumed to be restricted to health-care settings. However, recent molecular studies indicate that this is no longer the case; animals and foods might be involved in the changing epidemiology of CDIs in humans; and genome sequencing is disproving person-to-person transmission in hospitals. Although zoonotic and foodborne transmission have not been confirmed, it is evident that susceptible people can be inadvertently exposed to C. difficile from foods, animals, or their environment. Strains of epidemic clones present in humans are common in companion and food animals, raw meats, poultry products, vegetables, and ready-to-eat foods, including salads. In order to develop science-based prevention strategies, it is critical to understand how C. difficile reaches foods and humans. This review contextualizes the current understanding of CDIs in humans, animals, and foods. Based on available information, we propose a list of educational measures that could reduce the exposure of susceptible people to C. difficile. Enhanced educational efforts and behavior change targeting medical and non-medical personnel are needed.

Detection, treatment, and prevention of Clostridium difficile infection

Clostridium difficile is a gram-positive anaerobic bacillus responsible for approximately 1 of 5 cases of antibiotic-associated diarrhea. C difficile infection (CDI) is defined by at least 3 unformed stools in a 24-hour period and stool, endoscopic, or histopathologic test results that indicate the presence of this bacteria. The history of CDI research can be divided into early (before 2000) and modern eras (after 2000). C difficile was first described in 1935, and the characteristics and causes of CDI as well as therapies were identified during the early era of research. During the modern era, CDI has become a more common, aggressive nosocomial infection. Our understanding of the epidemiology, diagnosis, treatment, and prevention of CDI has increased at a rapid pace. We review features of CDI diagnosis, treatment, and prevention.

The roles of Clostridium difficile and norovirus among gastroenteritis-associated deaths in the United States, 1999-2007

BACKGROUND

Globally, gastroenteritis is recognized as an important contributor to mortality among children, but population-based data on gastroenteritis deaths among adults and the contributions of specific pathogens are limited. We aimed to describe trends in gastroenteritis deaths across all ages in the United States and specifically estimate the contributions of Clostridium difficile and norovirus.

METHODS

Gastroenteritis-associated deaths in the United States during 1999-2007 were identified from the National Center for Health Statistics multiple-cause-of-death mortality data. All deaths in which the underlying cause or any of the contributing causes listed gastroenteritis were included. Time-series regression models were used to identify cause-unspecified gastroenteritis deaths that were probably due to specific causes; seasonality of model residuals was analyzed to estimate norovirus-associated deaths.

RESULTS

Gastroenteritis mortality averaged 39/1000000 person-years (11 255 deaths per year) during the study period, increasing from 25/1 000 000 person-years in 1999-2000 to 57/1 000 000 person-years in 2006-2007 (P < .001). Adults aged ≥ 65 years accounted for 83% of gastroenteritis deaths (258/1 000 000 person-years). C. difficile mortality increased 5-fold from 10/1 000 000 person-years in 1999-2000 to 48/1 000 000 person-years in 2006-2007 (P < .001). Norovirus contributed to an estimated 797 deaths annually (3/1 000 000 person-years), with surges by up to 50% during epidemic seasons associated with emergent viral strains.

CONCLUSIONS

Gastroenteritis-associated mortality has more than doubled during the past decade, primarily affecting the elderly. C. difficile is the main contributor to gastroenteritis-associated deaths, largely accounting for the increasing trend, and norovirus is probably the second leading infectious cause. These findings can help guide appropriate clinical management strategies and vaccine development.

Reduction in Clostridium difficile infection rates after mandatory hospital public reporting: findings from a longitudinal cohort study in Canada

BACKGROUND

The role of public reporting in improving hospital quality of care is controversial. Reporting of hospital-acquired infection rates has been introduced in multiple health care systems, but its relationship to infection rates has been understudied. Our objective was to determine whether mandatory public reporting by hospitals is associated with a reduction in hospital rates of Clostridium difficile infection.

METHODS AND FINDINGS

We conducted a longitudinal, population-based cohort study in Ontario (Canada's largest province) between April 1, 2002, and March 31, 2010. We included all patients (>1 y old) admitted to 180 acute care hospitals. Using Poisson regression, we developed a model to predict hospital- and age-specific monthly rates of C. difficile disease per 10,000 patient-days prior to introduction of public reporting on September 1, 2008. We then compared observed monthly rates of C. difficile infection in the post-intervention period with rates predicted by the pre-intervention predictive model. In the pre-intervention period there were 33,634 cases of C. difficile infection during 39,221,113 hospital days, with rates increasing from 7.01 per 10,000 patient-days in 2002 to 10.79 in 2007. In the first calendar year after the introduction of public reporting, there was a decline in observed rates of C. difficile colitis in Ontario to 8.92 cases per 10,000 patient-days, which was significantly lower than the predicted rate of 12.16 (95% CI 11.35-13.04) cases per 10,000 patient-days (p<0.001). Over this period, public reporting was associated with a 26.7% (95% CI 21.4%-31.6%) reduction in C. difficile cases, or a projected 1,970 cases averted per year (95% CI 1,476-2,500). The effect was specific to C. difficile, with rates of community-acquired gastrointestinal infections and urinary tract infections unchanged. A limitation of our study is that this observational study design cannot rule out the influence of unmeasured temporal confounders.

CONCLUSIONS

Public reporting of hospital C. difficile rates was associated with a substantial reduction in the population burden of this infection. Future research will be required to discern the direct mechanism by which C. difficile infection rates may have been reduced in response to public reporting. Please see later in the article for the Editors' Summary.

Seasonality of Clostridium difficile infections in Southern Germany

Between 2000 and 2009, the total number of patients with Clostridium difficile infections increased considerably in Southeastern Germany. A clear seasonality was observed with a higher number of affected patients occurring in the winter months (January-March). Moxifloxacin and erythromycin-resistant C. difficile PCR ribotypes 001 (72%) and 027 (4·6%) were the most commonly isolated strains.

Seasonal variations in Clostridium difficile infections are associated with influenza and respiratory syncytial virus activity independently of antibiotic prescriptions: a time series analysis in Quebec, Canada

Seasonal variations in Clostridium difficile-associated diarrhea (CDAD), with a higher incidence occurring during winter months, have been reported. Although winter epidemics of respiratory viruses may be temporally associated with an increase in CDAD morbidity, we hypothesized that this association is mainly due to increased antibiotic use for respiratory infections. The objective of this study was to evaluate the effect of the two most frequent respiratory viruses (influenza virus and respiratory syncytial virus [RSV]) and antibiotics prescribed for respiratory infections (fluoroquinolones and macrolides) on the CDAD incidence in hospitals in the province of Québec, Canada. A multivariable Box-Jenkins transfer function model was built to relate monthly CDAD incidence to the monthly percentage of positive tests for influenza virus and RSV and monthly fluoroquinolone and macrolide prescriptions over a 4-year period (January 2005 to December 2008). Analysis showed that temporal variations in CDAD incidence followed temporal variations for influenza virus (P = 0.043), RSV (P = 0.004), and macrolide prescription (P = 0.05) time series with an average delay of 1 month and fluoroquinolone prescription time series with an average delay of 2 months (P = 0.01). We conclude that influenza virus and RSV circulation is independently associated with CDAD incidence after controlling for fluoroquinolone and macrolide use. This association was observed at an aggregated level and may be indicative of other phenomena occurring during wintertime.