[Clostridium difficile in visceral surgery]

BACKGROUND

For surgeons the early identification of patients with clostridium difficile infections (CDI) is important, because the incidence and virulence of this potentially life-threatening disease are increasing.

OBJECTIVES

The aim of this study was to describe the frequency of CDI among surgical patients, to analyze which treatment was successful and to define which factors were associated with mortality.

METHODS

A retrospective analysis of patients with CDI was performed.

RESULTS

From January 2004 to June 2012 the overall incidence of CDI among all departments at the St. Josef Hospital, Ruhr University Bochum was 0.6 % (1669 out of 301,919 patients). In 2004 the number of surgical patients with CDI was 1 which increased to 41 in 2011. Before the diagnosis of CDI was made 84 % (151 out of 179) of patients had received an antibiotic treatment. Conservative management of CDI was performed with metronidazole in 75 % (134 out of 179), 60 % (107 out of 179) received vancomycin, while 44 % (79 out of 179) received a combination of metronidazole and vancomycin, tygecycline or fidaxomidin. The overall mortality was 7 % (12 out of 179). There was a significant association with mortality for patients with sepsis, readmission to the intensive care unit (ICU), requirement for vasopressor therapy and intubation with mechanical ventilation. In 4 % of patients (7 out of 179) colectomy was carried out. Despite maximum intensive care management, 86 % (6 out of 7) of patients who underwent colectomy ultimately died.

CONCLUSION

Although conservative management is successful for most patients with CDI, the mortality is high for patients who require intensive care management secondary to CDI. Mortality after colectomy for CDI is almost 100 %, mostly because the operation is usually only performed as a last resort in patients with sepsis. The most important risk factor for CDI is a prior antibiotic therapy.

Predominance and high antibiotic resistance of the emerging Clostridium difficile genotypes NAPCR1 and NAP9 in a Costa Rican hospital over a 2-year period without outbreaks

Clostridium difficile is the major causative agent of nosocomial antibiotic-associated diarrhea. In a 2009 outbreak of C. difficile-associated diarrhea that was recorded in a major Costa Rican hospital, the hypervirulent NAP1 strain (45%) predominated together with a local genotype variant (NAP_CR1, 31%). Both strains were fluoroquinolone-resistant and the NAP_CR1 genotype, in addition, was resistant to clindamycin and rifampicin. We now report on the genotypes and antibiotic susceptibilities of 68 C. difficile isolates from a major Costa Rican hospital over a 2-year period without outbreaks. In contrast to our previous findings, no NAP1 strains were detected, and for the first time in a Costa Rican hospital, a significant fraction of the isolates were NAP9 strains (n=14, 21%). The local NAP_CR1 genotype remained prevalent (n=18, 26%) and coexisted with 14 strains (21%) of classic hospital NAP types (NAP2, NAP4, and NAP6), eight new genotypes (12%), four environmental strains classified as NAP10 or NAP11 (6%), three strains without NAP designation (4%) and seven non-toxigenic strains (10%). All 68 strains were resistant to ciprofloxacin, 88% were resistant to clindamycin and 50% were resistant to moxifloxacin and rifampicin. Metronidazole and vancomycin susceptibilities were universal. The NAP_CR1 and NAP9 strains, which have been associated with more severe clinical infections, were more resistant to antibiotics than the other strains. Altogether, our results confirm that the epidemiology of C. difficile infection is dynamic and that A⁻B⁺ strains from the NAP9 type are on the rise not only in the developed world. Moreover, our results reveal that the local NAP_CR1 strains still circulate in the country without causing outbreaks but with equally high antibiotic-resistance rates and levels.

Measuring the impact of antimicrobial stewardship programs

Antimicrobial Stewardship Programs (ASPs) are being implemented worldwide to optimize antimicrobial therapy, and thereby improve patient safety and quality of care. Additionally, this should counteract resistance development. It is, however, vital that correct and timely diagnostics are performed in parallel, and that an institution runs a well-organized infection prevention program. Currently, there is no clear consensus on which interventions an ASP should comprise. Indeed this depends on the institution, the region, and the patient population that is served. Different interventions will lead to different effects. Therefore, adequate evaluations, both clinically and financially, are crucial. Here, we provide a general overview of, and perspective on different intervention strategies and methods to evaluate these ASP programs, covering before mentioned topics. This should lead to a more consistent approach in evaluating these programs, making it easier to compare different interventions and studies with each other and ultimately improve infection and patient management.

Clostridium difficile infection following systemic antibiotic administration in randomised controlled trials: a systematic review and meta-analysis

Antibiotics have been the most important risk factor for Clostridium difficile infection (CDI). However, only data from non-randomised studies have been reviewed. We sought to evaluate the risk for development of CDI associated with the major antibiotic classes by analysing data from randomised controlled trials (RCTs). The PubMed, Cochrane and Scopus databases were searched and the references of selected RCTs were also hand-searched. Eligible studies should have compared only one antibiotic versus another administered systemically. Inclusion of studies comparing combinations of antibiotics was allowed only if the second antibiotic was the same or from the same class or if it was administered in a subset of the enrolled patients who were equally distributed in the two arms. Only a minority of the selected RCTs (79/1332; 5.9%) reported CDI episodes. Carbapenems were associated with more CDI episodes than fluoroquinolones [risk ratio (RR) = 2.44, 95% confidence interval (CI) 1.32-4.49] and cephalosporins (RR = 2.24, 95% CI 1.46-3.42), but not penicillins (RR = 2.53, 95% CI 0.87-7.41). Cephalosporins were associated with more CDIs than penicillins (RR = 2.36, 95% CI 1.32-4.23) and fluoroquinolones (RR = 2.84, 95% CI 1.60-5.06). There was no difference in CDI frequency between fluoroquinolones and penicillins (RR = 1.34, 95% CI 0.55-3.25). Finally, clindamycin was associated with more CDI episodes than cephalosporins and penicillins (RR = 3.92, 95% CI 1.15-13.43). In conclusion, data from RCTs showed that clindamycin and carbapenems were associated with more CDIs than other antibiotics.

Association Between High-Risk Medication Usage and Healthcare Facility-Onset C. difficile Infection

OBJECTIVE

National hospital performance measures for C. difficile infection (CD) are available; comparing antibacterial use among performance levels can aid in identifying effective antimicrobial stewardship strategies to reduce CDI rates.

DESIGN

Hospital-level, cross-sectional analysis.

METHODS

Hospital characteristics (ie, demographics, medications, patient mix) were obtained for 77 hospitals for 2013. Hospitals were assigned 1 of 3 levels of a CDI standardized infection ratio (SIR): ‘Worse than,’ ‘Better than,’ or ‘No different than’ a national benchmark. Analyses compared medication use (total and broad-spectrum antibacterials) for 3 metrics: days of therapy per 1,000 patient days; length of therapy; and proportion of patients receiving a medication across SIR levels. A multivariate, ordered-probit regression identified characteristics associated with SIR categories.

RESULTS

Regarding total average antimicrobial use per patient, there was a significant difference detected in mean length of therapy: ‘No different’ hospitals having the longest (4.93 days) versus ‘Worse’ (4.78 days) and ‘Better’ (4.43 days) (P<.01). ‘Better’ hospitals used fewer total antibacterials (693 days of therapy per 1,000 patient days) versus ‘No different’ (776 days) versus ‘Worse’ (777 days) (P<.05). The ‘Better’ hospitals used broad-spectrum antibacterials for a shorter average length of therapy (4.03 days) versus ‘No different’ (4.51 days) versus ‘Worse’ (4.38 days) (P<.05). ‘Better’ hospitals used fewer broad-spectrum antibacterials (310 days of therapy per 1,000 patient days) versus ‘No different’ (364 days) versus ‘Worse’ (349 days) (P<.05). Multivariate analysis revealed that the proportion of elderly patients and chemotherapy days of therapy per 1,000 patient days was significantly negatively associated with the SIR.

CONCLUSIONS

These findings have potential implications regarding the need to fully account for hospital patient mix when carrying out inter-hospital comparisons of CDI rates.

Infect Control Hosp Epidemiol 2016;37:909–915

Risk factors for Clostridium difficile infection in hospitalized patients with community-acquired pneumonia

OBJECTIVES

Clostridium difficile infection (CDI) is strongly associated with anti-biotic treatment, and community-acquired pneumonia (CAP) is the leading indication for anti-biotic prescription in hospitals. This study assessed the incidence of and risk factors for CDI in a cohort of patients hospitalized with CAP.

METHODS

We analysed data from a prospective, observational cohort of patients with CAP in Edinburgh, UK. Patients with diarrhoea were systematically screened for CDI, and risk factors were determined through time-dependent survival analysis.

RESULTS

Overall, 1883 patients with CAP were included, 365 developed diarrhoea and 61 had laboratory-confirmed CDI. The risk factors for CDI were: age (hazard ratio [HR], 1.06 per year; 95% confidence interval [CI], 1.03-1.08), total number of antibiotic classes received (HR, 3.01 per class; 95% CI, 2.32-3.91), duration of antibiotic therapy (HR, 1.09 per day; 95% CI, 1.00-1.19 and hospitalization status (HR, 13.1; 95% CI, 6.0-28.7). Antibiotic class was not an independent predictor of CDI when adjusted for these risk factors (P > 0.05 by interaction testing).

CONCLUSIONS

These data suggest that reducing the overall antibiotic burden, duration of antibiotic treatment and duration of hospital stay may reduce the incidence of CDI in patients with CAP.

Clostridium difficile infection: a review of current and emerging therapies

Clostridium difficile (C. difficile) infection (CDI) is the most common cause of ­healthcare-associated infections in US hospitals. The epidemic strain NAP1/BI/ribotype 027 accounts for outbreaks worldwide, with increasing mortality and severity. CDI is acquired from an endogenous source or from spores in the environment, most easily acquired during the hospital stay. The use of antimicrobials disrupts the intestinal microflora enabling C. difficile to proliferate in the colon and produce toxins. Clinical diagnosis in symptomatic patients requires toxin detection from stool specimens and rarely in combination with stool culture to increase sensitivity. However, stool culture is essential for epidemiological studies. Oral metronidazole is the recommended therapy for milder cases of CDI and oral vancomycin or fidaxomicin for more severe cases. Treatment of first recurrence involves the use of the same therapy used in the initial CDI. In the event of a second recurrence oral vancomycin often given in a tapered dose or intermittently, or fidaxomicin may be used. Fecal transplantation is playing an immense role in therapy of recurrent CDI with remarkable results. Fulminant colitis and toxic megacolon warrant surgical intervention. Novel approaches including new antibiotics and immunotherapy against CDI or its toxins appear to be of potential value.

Clostridium difficile infection

Infection of the colon with the Gram-positive bacterium Clostridium difficile is potentially life threatening, especially in elderly people and in patients who have dysbiosis of the gut microbiota following antimicrobial drug exposure. C. difficile is the leading cause of health-care-associated infective diarrhoea. The life cycle of C. difficile is influenced by antimicrobial agents, the host immune system, and the host microbiota and its associated metabolites. The primary mediators of inflammation in C. difficile infection (CDI) are large clostridial toxins, toxin A (TcdA) and toxin B (TcdB), and, in some bacterial strains, the binary toxin CDT. The toxins trigger a complex cascade of host cellular responses to cause diarrhoea, inflammation and tissue necrosis - the major symptoms of CDI. The factors responsible for the epidemic of some C. difficile strains are poorly understood. Recurrent infections are common and can be debilitating. Toxin detection for diagnosis is important for accurate epidemiological study, and for optimal management and prevention strategies. Infections are commonly treated with specific antimicrobial agents, but faecal microbiota transplants have shown promise for recurrent infections. Future biotherapies for C. difficile infections are likely to involve defined combinations of key gut microbiota.

Expanding the statistical toolbox: analytic approaches for cohort studies with healthcare-associated infectious outcomes

PURPOSE OF REVIEW

Healthcare-associated infections (HAIs) are a leading cause of adverse patient outcomes. Further elucidation of the etiology of these infections and the pathogens that cause them has been a primary goal of research in infection control and healthcare epidemiology. Longitudinal studies, in particular, afford a range of statistical methods to better understand the process of pathogen acquisition or HAI development. This review intends to convey the scope of available statistical methodology.

RECENT FINDINGS

Despite the range of methods available, logistic regression remains the dominant statistical approach in use. Poisson regression, survival methods, and mechanistic (mathematical) models remain underutilized. Recent studies that use these approaches are looking beyond associations to answer questions about the timing, duration, and mechanism of infectious risk.

SUMMARY

Logistic regression remains an important approach to the study of HAIs, but in the context of cohort studies, it is most appropriate for short observation periods, during which mechanism is not of primary interest. Additional statistical methodologies are available to build upon risk factor analysis to better inform the process of risk and infection in the hospital setting.

Glycosyltransferases and Transpeptidases/Penicillin-Binding Proteins: Valuable Targets for New Antibacterials

Peptidoglycan (PG) is an essential macromolecular sacculus surrounding most bacteria. It is assembled by the glycosyltransferase (GT) and transpeptidase (TP) activities of multimodular penicillin-binding proteins (PBPs) within multiprotein complex machineries. Both activities are essential for the synthesis of a functional stress-bearing PG shell. Although good progress has been made in terms of the functional and structural understanding of GT, finding a clinically useful antibiotic against them has been challenging until now. In contrast, the TP/PBP module has been successfully targeted by β-lactam derivatives, but the extensive use of these antibiotics has selected resistant bacterial strains that employ a wide variety of mechanisms to escape the lethal action of these antibiotics. In addition to traditional β-lactams, other classes of molecules (non-β-lactams) that inhibit PBPs are now emerging, opening new perspectives for tackling the resistance problem while taking advantage of these valuable targets, for which a wealth of structural and functional knowledge has been accumulated. The overall evidence shows that PBPs are part of multiprotein machineries whose activities are modulated by cofactors. Perturbation of these systems could lead to lethal effects. Developing screening strategies to take advantage of these mechanisms could lead to new inhibitors of PG assembly. In this paper, we present a general background on the GTs and TPs/PBPs, a survey of recent issues of bacterial resistance and a review of recent works describing new inhibitors of these enzymes.

Recent advances in the understanding of antibiotic resistance in Clostridium difficile infection

Clostridium difficile epidemiology has changed in recent years, with the emergence of highly virulent types associated with severe infections, high rates of recurrences and mortality. Antibiotic resistance plays an important role in driving these epidemiological changes and the emergence of new types. While clindamycin resistance was driving historical endemic types, new types are associated with resistance to fluoroquinolones. Furthermore, resistance to multiple antibiotics is a common feature of the newly emergent strains and, in general, of many epidemic isolates. A reduced susceptibility to antibiotics used for C. difficile infection (CDI) treatment, in particular to metronidazole, has recently been described in several studies. Furthermore, an increased number of strains show resistance to rifamycins, used for the treatment of relapsing CDI. Several mechanisms of resistance have been identified in C. difficile, including acquisition of genetic elements and alterations of the antibiotic target sites. The C. difficile genome contains a plethora of mobile genetic elements, many of them involved in antibiotic resistance. Transfer of genetic elements among C. difficile strains or between C. difficile and other bacterial species can occur through different mechanisms that facilitate their spread. Investigations of the fitness cost in C. difficile indicate that both genetic elements and mutations in the molecular targets of antibiotics can be maintained regardless of the burden imposed on fitness, suggesting that resistances may persist in the C. difficile population also in absence of antibiotic selective pressure. The rapid evolution of antibiotic resistance and its composite nature complicate strategies in the treatment and prevention of CDI. The rapid identification of new phenotypic and genotypic traits, the implementation of effective antimicrobial stewardship and infection control programs, and the development of alternative therapies are needed to prevent and contain the spread of resistance and to ensure an efficacious therapy for CDI.

Antibiotic Treatment of Hospitalized Patients with Pneumonia Complicated by Clostridium Difficile Infection

Clostridium difficile infection (CDI) is one of the most common gastrointestinal complication after antimicrobial treatment. It is estimated that CDI after pneumonia treatment is connected with a higher mortality than other causes of hospitalization. The aim of the study was to assess the relationship between the kind of antibiotic used for pneumonia treatment and mortality from post-pneumonia CDI. We addressed the issue by examining retrospectively the records of 217 patients who met the diagnostic criteria of CDI. Ninety four of those patients (43.3 %) came down with CDI infection after pneumonia treatment. Fifty of the 94 patients went through severe or severe and complicated CDI. The distribution of antecedent antibiotic treatment of pneumonia in these 50 patients was as follows: ceftriaxone in 14 (28 %) cases, amoxicillin with clavulanate in 9 (18 %), ciprofloxacin in 8 (16.0 %), clarithromycin in 7 (14 %), and cefuroxime and imipenem in 6 (12 %) each. The findings revealed a borderline enhancement in the proportion of deaths due to CDI in the ceftriaxone group compared with the ciprofloxacin, cefuroxime, and imipenem groups. The corollary is that ceftriaxone should be shunned in pneumonia treatment. The study demonstrates an association between the use of a specific antibiotic for pneumonia treatment and post-pneumonia mortality in patients who developed CDI.

Antimicrobials: a global alliance for optimizing their rational use in intra-abdominal infections (AGORA)

Intra-abdominal infections (IAI) are an important cause of morbidity and are frequently associated with poor prognosis, particularly in high-risk patients. The cornerstones in the management of complicated IAIs are timely effective source control with appropriate antimicrobial therapy. Empiric antimicrobial therapy is important in the management of intra-abdominal infections and must be broad enough to cover all likely organisms because inappropriate initial antimicrobial therapy is associated with poor patient outcomes and the development of bacterial resistance. The overuse of antimicrobials is widely accepted as a major driver of some emerging infections (such as C. difficile), the selection of resistant pathogens in individual patients, and for the continued development of antimicrobial resistance globally. The growing emergence of multi-drug resistant organisms and the limited development of new agents available to counteract them have caused an impending crisis with alarming implications, especially with regards to Gram-negative bacteria. An international task force from 79 different countries has joined this project by sharing a document on the rational use of antimicrobials for patients with IAIs. The project has been termed AGORA (Antimicrobials: A Global Alliance for Optimizing their Rational Use in Intra-Abdominal Infections). The authors hope that AGORA, involving many of the world's leading experts, can actively raise awareness in health workers and can improve prescribing behavior in treating IAIs.

Treatment for Positive Urine Cultures in Hospitalized Adults: A Survey of Prevalence and Risk Factors in 3 Medical Centers

BACKGROUND

Antibiotic treatment for asymptomatic bacteriuria (ASB) is prevalent but often contrary to published guidelines.

OBJECTIVE

To evaluate risk factors for treatment of ASB.

DESIGN

Retrospective observational study.

SETTING

A tertiary academic hospital, county hospital, and community hospital.

PATIENTS

Hospitalized adults with bacteriuria.

METHODS

Patients without documented symptoms of urinary tract infection per Infectious Diseases Society of America (IDSA) criteria were classified as ASB. We examined ASB treatment risk factors as well as broad-spectrum antibiotic usage and quantified diagnostic concordance between IDSA and National Healthcare Safety Network criteria.

RESULTS

Among 300 patients with bacteriuria, ASB was present in 71% by IDSA criteria. By National Healthcare Safety Network criteria, 71% of patients had ASB; within-patient diagnostic concordance with IDSA was moderate (kappa, 0.52). After excluding those given antibiotics for nonurinary indications, antibiotics were given to 38% (62/164) with ASB. Factors significantly associated with ASB treatment were elevated urine white cell count (65 vs 24 white blood cells per high-powered field, P<.01), hospital identity (hospital C vs A, odds ratio, 0.34 [95% CI, 0.14-0.80], P =.01), presence of leukocyte esterase (5.48 [2.35-12.79], P<.01), presence of nitrites (2.45 [1.11-5.41], P=.03), and Escherichia coli on culture (2.4 [1.2-4.7], P=.01). Of patients treated for ASB, broad-spectrum antibiotics were used in 84%.

CONCLUSIONS

ASB treatment was prevalent across settings and contributed to broad-spectrum antibiotic use. Associating abnormal urinalysis results with the need for antibiotic treatment regardless of symptoms may drive unnecessary antibiotic use.

Hospitalization Type and Subsequent Severe Sepsis

RATIONALE

Hospitalization is associated with microbiome perturbation (dysbiosis), and this perturbation is more severe in patients treated with antimicrobials.

OBJECTIVES

To evaluate whether hospitalizations known to be associated with periods of microbiome perturbation are associated with increased risk of severe sepsis after hospital discharge.

METHODS

We studied participants in the U.S. Health and Retirement Study with linked Medicare claims (1998-2010). We measured whether three hospitalization types associated with increasing severity of probable dysbiosis (non-infection-related hospitalization, infection-related hospitalization, and hospitalization with Clostridium difficile infection [CDI]) were associated with increasing risk for severe sepsis in the 90 days after hospital discharge. We used two study designs: the first was a longitudinal design with between-person comparisons and the second was a self-controlled case series design using within-person comparison.

MEASUREMENTS AND MAIN RESULTS

We identified 43,095 hospitalizations among 10,996 Health and Retirement Study-Medicare participants. In the 90 days following non-infection-related hospitalization, infection-related hospitalization, and hospitalization with CDI, adjusted probabilities of subsequent admission for severe sepsis were 4.1% (95% confidence interval [CI], 3.8-4.4%), 7.1% (95% CI, 6.6-7.6%), and 10.7% (95% CI, 7.7-13.8%), respectively. The incidence rate ratio (IRR) of severe sepsis was 3.3-fold greater during the 90 days after hospitalizations than during other observation periods. The IRR was 30% greater after an infection-related hospitalization versus a non-infection-related hospitalization. The IRR was 70% greater after a hospitalization with CDI than an infection-related hospitalization without CDI.

CONCLUSIONS

There is a strong dose-response relationship between events known to result in dysbiosis and subsequent severe sepsis hospitalization that is not present for rehospitalization for nonsepsis diagnoses.

Gastrointestinal dysbiosis and the use of fecal microbial transplantation in Clostridium difficile infection

The impact of antibiotics on the human gut microbiota is a significant concern. Antibiotic-associated diarrhea has been on the rise for the past few decades with the increasing usage of antibiotics. Clostridium difficile infections (CDI) have become one of the most prominent types of infectious diarrheal disease, with dramatically increased incidence in both the hospital and community setting worldwide. Studies show that variability in the innate host response may in part impact upon CDI severity in patients. That being said, CDI is a disease that shows the most prominent links to alterations to the gut microbiota, in both cause and treatment. With recurrence rates still relatively high, it is important to explore alternative therapies to CDI. Fecal microbiota transplantation (FMT) and other types of bacteriotherapy have become exciting avenues of treatment for CDI. Recent clinical trials have generated excitement for the use of FMT as a therapeutic option for CDI; however, the exact components of the human gut microbiota needed for protection against CDI have remained elusive. Additional investigations on the effects of antibiotics on the human gut microbiota and subsequent CDI will help reduce the socioeconomic burden of CDI and potentially lead to new therapeutic modalities.

Management of diverticular disease

Diverticular disease is a common condition in Western countries and the incidence and prevalence of the disease is increasing. The pathogenetic factors involved include structural changes in the gut that increase with age, a diet low in fibre and rich in meat, changes in intestinal motility, the concept of enteric neuropathy and an underlying genetic background. Current treatment strategies are hampered by insufficient options to stratify patients according to individual risk. One of the main reasons is the lack of an all-encompassing classification system of diverticular disease. In response, the German Society for Gastroenterology and Digestive Diseases (DGVS) has proposed a classification system as part of its new guideline for the diagnosis and management of diverticular disease. The classification system includes five main types of disease: asymptomatic diverticulosis, acute uncomplicated and complicated diverticulitis, as well as chronic diverticular disease and diverticular bleeding. Here, we review prevention and treatment strategies stratified by these five main types of disease, from prevention of the first attack of diverticulitis to the management of chronic complications and diverticular bleeding.

Rapid detection of ermB gene in Clostridium difficile by loop-mediated isothermal amplification

Macrolide-lincosamide-streptogramin B resistance in Clostridium difficile is mostly due to the ermB resistance determinant. Here, we describe a sensitive and rapid molecular method to detect ermB in C. difficile to contribute to the wider epidemiological study. Five sets of loop-mediated isothermal amplification (LAMP) primers were designed and optimized for rapid detection of ermB. The specificity and sensitivity of the primers for ermB were detected, and the ermB LAMP assay was compared to conventional PCR with 80 clinical isolates of C. difficile. Real-time monitoring of turbidity and chromogenic reaction were used to determine negative and positive results. A total of 26 pathogenic bacterial strains of different species were found to be negative for ermB, which indicated the high specificity of the primers. ermB was detected in 78.8 % (63/80) of the clinical isolates by both LAMP and conventional PCR. The detection limit of LAMP was 36.1  pg DNA μl- 1 and its sensitivity was 10-fold greater than that of conventional PCR. This study is the first report regarding the development and application of the LAMP assay for detection of the ermB gene in C. difficile strains. The developed LAMP method is sensitive, specific and provides a user-friendly visual approach for the rapid detection of ermB-bearing C. difficile.

Multimorbidity in elderly hospitalised patients and risk of Clostridium difficile infection: a retrospective study with the Cumulative Illness Rating Scale (CIRS)

OBJECTIVES

To identify the role of chronic comorbidities, considered together in a literature-validated index (Cumulative Illness Rating Scale, CIRS), and antibiotic or proton-pump inhibitor (PPI) treatments as risk factors for hospital-acquired Clostridium difficile infection (CDI) in elderly multimorbid hospitalised patients.

DESIGN

Retrospective cohort study.

SETTING

Subacute hospital geriatric care ward in Italy.

PARTICIPANTS

505 (238 male (M), 268 female (F)) elderly (age≥65) multimorbid patients.

MAIN OUTCOME MEASURES

The relationship between CDI and CIRS Comorbidity Score, number of comorbidities, antibiotic, antifungal and PPI treatments, and length of hospital stay was assessed through age-adjusted and sex-adjusted and multivariate logistic regression models. The CIRS Comorbidity Score was handled after categorisation in quartiles.

RESULTS

Mean age was 80.7±11.3 years. 43 patients (22 M, 21 F) developed CDI. The prevalence of CDI increased among quartiles of CIRS Comorbidity Score (3.9% first quartile vs 11.1% fourth quartile, age-adjusted and sex-adjusted p=0.03). In the multivariate logistic regression analysis, patients in the highest quartile of CIRS Comorbidity Score (≥17) carried a significantly higher risk of CDI (OR 5.07, 95% CI 1.28 to 20.14, p=0.02) than patients in the lowest quartile (<9). The only other variable significantly associated with CDI was antibiotic therapy (OR 2.62, 95% CI 1.21 to 5.66, p=0.01). PPI treatment was not associated with CDI.

CONCLUSIONS

Multimorbidity, measured through CIRS Comorbidity Score, is independently associated with the risk of CDI in a population of elderly patients with prolonged hospital stay.

Antibiotic prophylaxis and risk of Clostridium difficile infection after coronary artery bypass graft surgery

OBJECTIVE

Antibiotic use, particularly type and duration, is a crucial modifiable risk factor for Clostridium difficile. Cardiac surgery is of particular interest because prophylactic antibiotics are recommended for 48 hours or less (vs ≤24 hours for noncardiac surgery), with increasing vancomycin use. We aimed to study associations between antibiotic prophylaxis (duration/vancomycin use) and C difficile among patients undergoing coronary artery bypass grafting.

METHODS

We extracted data on coronary artery bypass grafting procedures from the national Premier Perspective claims database (2006-2013, n = 154,200, 233 hospitals). Multilevel multivariable logistic regressions measured associations between (1) duration (<2 days, "standard" vs ≥2 days, "extended") and (2) type of antibiotic used ("cephalosporin," "cephalosporin + vancomycin," "vancomycin") and C difficile as outcome.

RESULTS

Overall C difficile prevalence was 0.21% (n = 329). Most patients (59.7%) received a cephalosporin only; in 33.1% vancomycin was added, whereas 7.2% received vancomycin only. Extended prophylaxis was used in 20.9%. In adjusted analyses, extended prophylaxis (vs standard) was associated with significantly increased C difficile risk (odds ratio, 1.43; confidence interval, 1.07-1.92), whereas no significant associations existed for vancomycin use as adjuvant or primary prophylactic compared with the use of cephalosporins (odds ratio, 1.21; confidence interval, 0.92-1.60, and odds ratio, 1.39; confidence interval, 0.94-2.05, respectively). Substantial inter-hospital variation exists in the percentage of extended antibiotic prophylaxis (interquartile range, 2.5-35.7), use of adjuvant vancomycin (interquartile range, 4.2-61.1), and vancomycin alone (interquartile range, 2.3-10.4).

CONCLUSIONS

Although extended use of antibiotic prophylaxis was associated with increased C difficile risk after coronary artery bypass grafting, vancomycin use was not. The observed hospital variation in antibiotic prophylaxis practices suggests great potential for efforts aimed at standardizing practices that subsequently could reduce C difficile risk.

A Comprehensive Assessment Across the Healthcare Continuum: Risk of Hospital-Associated Clostridium difficile Infection Due to Outpatient and Inpatient Antibiotic Exposure

BACKGROUND

Limitations in sample size, overly inclusive antibiotic classes, lack of adjustment of key risk variables, and inadequate assessment of cases contribute to widely ranging estimates of risk factors for Clostridium difficile infection (CDI).

OBJECTIVE

To incorporate all key CDI risk factors in addition to 27 antibiotic classes into a single comprehensive model.

DESIGN

Retrospective cohort study.

SETTING

Kaiser Permanente Southern California.

PATIENTS

Members of Kaiser Permanente Southern California at least 18 years old admitted to any of its 14 hospitals from January 1, 2011, through December 31, 2012.

METHODS

Hospital-acquired CDI cases were identified by polymerase chain reaction assay. Exposure to major outpatient antibiotics (10 classes) and those administered during inpatient stays (27 classes) was assessed. Age, sex, self-identified race/ethnicity, Charlson Comorbidity Score, previous hospitalization, transfer from a skilled nursing facility, number of different antibiotic classes, statin use, and proton pump inhibitor use were also assessed. Poisson regression estimated adjusted risk of CDI.

RESULTS

A total of 401,234 patients with 2,638 cases of incident CDI (0.7%) were detected. The final model demonstrated highest CDI risk associated with increasing age, exposure to multiple antibiotic classes, and skilled nursing facility transfer. Factors conferring the most reduced CDI risk were inpatient exposure to tetracyclines and first-generation cephalosporins, and outpatient macrolides. CONCLUSIONS Although type and aggregate antibiotic exposure are important, the factors that increase the likelihood of environmental spore acquisition should not be underestimated. Operationally, our findings have implications for antibiotic stewardship efforts and can inform empirical and culture-driven treatment approaches.

Reappearance and treatment of penicillin-susceptible Staphylococcus aureus in a tertiary medical centre

OBJECTIVES

The purpose of this study was to describe trends in the prevalence and treatment patterns of penicillin-susceptible Staphylococcus aureus (SA) infections.

METHODS

This was a cross-sectional study of MSSA isolates from blood cultures at a tertiary-care centre between 1 January 2003 and 31 December 2012. All blood cultures positive for MSSA drawn during the study period were used to calculate the prevalence of penicillin-susceptible SA. Repeat cultures were excluded if they were isolated within 6 weeks of the index culture. The analysis was then restricted to inpatient blood cultures to assess treatment patterns. Antibiotics administered 48-96 h after the culture were analysed.

RESULTS

A total of 446 blood cultures positive for MSSA were included in the analysis. There was a distinct trend showing an increase in the percentage of penicillin-susceptible SA over 10 years from 13.2% (95% CI 4.1%-22.3%) in 2003 to 32.4% (95% CI 17.3%-47.5%) in 2012 (P trend <0.001). During the study period, penicillin use for penicillin-susceptible SA bacteraemia increased from 0.0% in 2003-04 to 50.0% in 2011-12 (P trend = 0.007).

CONCLUSIONS

Over a decade, there was an ∼3-fold increase in penicillin susceptibility among MSSA blood cultures at a large tertiary-care facility. Although treatment with penicillin increased over the study period, only 50% of penicillin-susceptible SA was treated with penicillin in the final study period. This study suggests that while susceptibility to penicillin appears to be returning in SA, the use of penicillin for penicillin-susceptible SA bacteraemia is low.

Ceftolozane-tazobactam activity against phylogenetically diverse Clostridium difficile strains

Ceftolozane-tazobactam (C/T) is approved for the treatment of complicated intra-abdominal and urinary tract infections and has varied activity against anaerobic bacteria. Here, we evaluate the activity of C/T against a phylogenetically diverse collection of Clostridium difficile isolates and report uniformly high MICs (≥256 μg/ml) to C/T.

Recurrent Clostridium difficile infection: From colonization to cure

Clostridium difficile infection (CDI) is increasingly prevalent, dangerous and challenging to prevent and manage. Despite intense national and international attention the incidence of primary and of recurrent CDI (PCDI and RCDI, respectively) have risen rapidly throughout the past decade. Of major concern is the increase in cases of RCDI resulting in substantial morbidity, morality and economic burden. RCDI management remains challenging as there is no uniformly effective therapy, no firm consensus on optimal treatment, and reliable data regarding RCDI-specific treatment options is scant. Novel therapeutic strategies are critically needed to rapidly, accurately, and effectively identify and treat patients with, or at-risk for, RCDI. In this review we consider the factors implicated in the epidemiology, pathogenesis and clinical presentation of RCDI, evaluate current management options for RCDI and explore novel and emerging therapies.

Impact of fluoroquinolones on human microbiota. Focus on the emergence of antibiotic resistance

The aggregate of microorganisms residing on the surface of the skin, in the oropharynx and in the GI tract, known as the human microbiota, play a major role as natural reservoirs for bacterial resistance to antibiotics. Fluoroquinolones (FQ) are among the most prescribed antibiotics and a major increase in FQ resistance is occurring worldwide. High concentrations of FQ are found in microbial ecosystems explaining their profound effect on the clinically relevant bacteria that compose them. Yet, because of different local pharmacokinetics, distinct selective pressures occur in the different microbiota. Here we review the qualitative and quantitative impact of FQ on the three main human microbiota and their consequences, particularly in terms of emergence of antibiotic resistance. Finally, we review potential actions that could decrease the impact of FQs on microbiota.

Amoxicillin plus temocillin as an alternative empiric therapy for the treatment of severe hospital-acquired pneumonia: results from a retrospective audit

A formulary decision was made at a large provider of acute hospital services in Surrey to replace piperacillin/tazobactam with amoxicillin+temocillin for the empiric treatment of severe hospital-acquired pneumonia. This decision was made because the use of broad-spectrum-β-lactam antibiotics is a known risk factor for Clostridium difficile infection (CDI) and for the selection of resistance. After the antibiotic formulary was changed, a retrospective audit was conducted to assess the effect of this change. Data from patients hospitalised between January 2011 and July 2012 for severe hospital-acquired pneumonia and treated empirically with piperacillin/tazobactam or amoxicillin+temocillin were reviewed retrospectively. Clinical characteristics of patients, data related to the episode of pneumonia, clinical success and incidence of significant diarrhoea and CDI were analysed. One hundred ninety-two episodes of severe hospital-acquired pneumonia in 188 patients were identified from hospital records. Ninety-eight patients received piperacillin/tazobactam and 94 amoxicillin+temocillin. At baseline, the two treatment groups were comparable, except that more patients with renal insufficiency were treated with piperacillin/tazobactam. Clinical success was comparable (80 versus 82 %; P = 0.86), but differences were observed between piperacillin/tazobactam and amoxicillin+temocillin for the rates of significant diarrhoea (34 versus 4 %, respectively; P < 0.0001) and for CDI (7 versus 0 %, respectively; P < 0.0028). This preliminary study suggests that the combination amoxicillin+temocillin is a viable alternative to piperacillin/tazobactam for the treatment of severe hospital-acquired pneumonia. This combination appears to be associated with fewer gastrointestinal adverse events. Further studies are needed to evaluate the place of amoxicillin+temocillin as empiric treatment of severe hospital-acquired pneumonia.

Risk Factors for Acquisition and Loss of Clostridium difficile Colonization in Hospitalized Patients

Asymptomatic colonization may contribute to Clostridium difficile transmission. Few data identify which patients are at risk for colonization. We performed a prospective cohort study of C. difficile colonization and risk factors for C. difficile acquisition and loss in hospitalized patients. Patients admitted to medical or surgical wards at a tertiary care hospital were enrolled; interviews and chart review were performed to determine patient demographics, C. difficile infection (CDI) history, medications, and health care exposures. Stool samples/rectal swabs were collected at enrollment and discharge; stool samples from clinical laboratory tests were also included. Samples were cultured for C. difficile, and the isolates were tested for toxins A and B and ribotyped. Chi-square tests and univariate logistic regression were used for the analyses. Two hundred thirty-five patients were enrolled. Of the patients, 21% were colonized with C. difficile (toxigenic and nontoxigenic) at admission and 24% at discharge. Ribotype 027 accounted for 6% of the strains at admission and 12% at discharge. Of the patients colonized at admission, 78% were also colonized at discharge. Cephalosporin use was associated with C. difficile acquisition (47% of patients who acquired C. difficile versus 25% of patients who did not; P = 0.03). β-lactam-β-lactamase inhibitor combinations were associated with a loss of C. difficile colonization (36% of patients who lost C. difficile colonization versus 8% of patients colonized at both admission and discharge; P = 0.04), as was metronidazole (27% versus 3%; P = 0.03). Antibiotic use affects the epidemiology of asymptomatic C. difficile colonization, including acquisition and loss, and it requires additional study.

Molecular characterization and antimicrobial susceptibilities of Clostridium difficile clinical isolates from Victoria, Australia

Some Australian strain types of Clostridium difficile appear unique, highlighting the global diversity of this bacterium. We examined recent and historic local isolates, finding predominantly toxinotype 0 strains, but also toxinotypes V and VIII. All isolates tested were susceptible to vancomycin and metronidazole, while moxifloxacin resistance was only detected in recent strains.

Loss of Microbiota-Mediated Colonization Resistance to Clostridium difficile Infection With Oral Vancomycin Compared With Metronidazole

Antibiotic administration disrupts the intestinal microbiota, increasing susceptibility to pathogens such as Clostridium difficile. Metronidazole or oral vancomycin can cure C. difficile infection, and administration of these agents to prevent C. difficile infection in high-risk patients, although not sanctioned by Infectious Disease Society of America guidelines, has been considered. The relative impacts of metronidazole and vancomycin on the intestinal microbiota and colonization resistance are unknown. We investigated the effect of brief treatment with metronidazole and/or oral vancomycin on susceptibility to C. difficile, vancomycin-resistant Enterococcus, carbapenem-resistant Klebsiella pneumoniae, and Escherichia coli infection in mice. Although metronidazole resulted in transient loss of colonization resistance, oral vancomycin markedly disrupted the microbiota, leading to prolonged loss of colonization resistance to C. difficile infection and dense colonization by vancomycin-resistant Enterococcus, K. pneumoniae, and E. coli. Our results demonstrate that vancomycin, and to a lesser extent metronidazole, are associated with marked intestinal microbiota destruction and greater risk of colonization by nosocomial pathogens.

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.

Clostridium difficile infection: risk factors, diagnosis and management

OPINION STATEMENT

Clostridium difficile infection (CDI) is the leading cause of death due to gastrointestinal infections in the US and is the most common cause of nosocomial diarrhea. The emergence of a hypervirulent strain in the early 2000s has been associated with a dramatic increase in the number and severity of cases in the US, Canada, and several other countries. Most cases are related to antibiotic use, but sporadic cases occur in otherwise healthy individuals with no risk factors. Morbidity and mortality are highest in the elderly. Diagnosis is confirmed by detection of C. difficile toxin in the stools. Treatment should be stratified by severity of disease, with metronidazole use for mild disease cases and vancomycin for severe disease. Recurrent CDI occurs in 10-20 % of cases. A first recurrence can be treated with a ten-day regimen of metronidazole or vancomycin; a second recurrence is best treated by a pulsed regimen of vancomycin. In patients with multiple (three or more) recurrences, fecal microbiota transplant has a high rate of success. The most important methods of prevention are wise antibiotic policies, hand hygiene, isolation, and barrier methods in hospital and long-term care facilities (LCTF) settings.

Diagnosis and treatment of Clostridium difficile in adults: a systematic review

IMPORTANCE

Since 2000, the incidence and severity of Clostridium difficile infection (CDI) have increased.

OBJECTIVE

To review current evidence regarding best practices for the diagnosis and treatment of CDI in adults (age ≥ 18 years).

EVIDENCE REVIEW

Ovid MEDLINE and Cochrane databases were searched using keywords relevant to the diagnosis and treatment of CDI in adults. Articles published between January 1978 and October 31, 2014, were selected for inclusion based on targeted keyword searches, manual review of bibliographies, and whether the article was a guideline, systematic review, or meta-analysis published within the past 10 years. Of 4682 articles initially identified, 196 were selected for full review. Of these, the most pertinent 116 articles were included. Clinical trials, large observational studies, and more recently published articles were prioritized in the selection process.

FINDINGS

Laboratory testing cannot distinguish between asymptomatic colonization and symptomatic infection with C difficile. Diagnostic approaches are complex due to the availability of multiple testing strategies. Multistep algorithms using polymerase chain reaction (PCR) for the toxin gene(s) or single-step PCR on liquid stool samples have the best test performance characteristics (for multistep: sensitivity was 0.68-1.00 and specificity was 0.92-1.00; and for single step: sensitivity was 0.86-0.92 and specificity was 0.94-0.97). Vancomycin and metronidazole are first-line therapies for most patients, although treatment failures have been associated with metronidazole in severe or complicated cases of CDI. Recent data demonstrate clinical success rates of 66.3% for metronidazole vs 78.5% for vancomycin for severe CDI. Newer therapies show promising results, including fidaxomicin (similar clinical cure rates to vancomycin, with lower recurrence rates for fidaxomicin, 15.4% vs vancomycin, 25.3%; P = .005) and fecal microbiota transplantation (response rates of 83%-94% for recurrent CDI).

CONCLUSIONS AND RELEVANCE

Diagnostic testing for CDI should be performed only in symptomatic patients. Treatment strategies should be based on disease severity, history of prior CDI, and the individual patient's risk of recurrence. Vancomycin is the treatment of choice for severe or complicated CDI, with or without adjunctive therapies. Metronidazole is appropriate for mild disease. Fidaxomicin is a therapeutic option for patients with recurrent CDI or a high risk of recurrence. Fecal microbiota transplantation is associated with symptom resolution of recurrent CDI but its role in primary and severe CDI is not established.

Risk of Clostridium difficile infection in intensive care unit patients with sepsis exposed to metronidazole

BACKGROUND

Antimicrobial agents used to treat Clostridium difficile infection (CDI), such as metronidazole and vancomycin, have been used during antibiotic treatment of other infections to try to prevent the development of CDI. We evaluated the hypothesis that intensive care unit (ICU) patients who receive metronidazole as part of an antibiotic treatment regimen for sepsis have a lower risk of subsequently developing CDI.

METHODS

This was a nested case-control study in a cohort of ICU patients who received antibiotic therapy for sepsis.

RESULTS

A total of 10 012 patients aged ≥ 18 years were admitted to the Cooper University Hospital medical/surgical ICU from 1/1/2003 to 12/31/2008. After applying inclusion criteria including having received antibiotic therapy for sepsis and subsequently having developed CDI, 67 cases were identified. The cases were matched for age, gender, date of ICU admission, and hospital length of stay to 67 controls that also received antibiotic therapy for sepsis but did not subsequently develop CDI. In the multivariate analysis, there was no association between metronidazole exposure and the risk of CDI (odds ratio (OR) = 0.57; p = 0.23). The only significant associations on multivariate analysis were antifungal therapy (OR = 0.30; p = 0.02) and aminoglycoside and/or colistin therapy (OR = 0.17; p = 0.02).

CONCLUSIONS

No association was found between metronidazole use and subsequent CDI in ICU patients who received antibiotic therapy for sepsis.

Predictive values of models of Clostridium difficile infection

In vivo and in vitro models are widely used to simulate Clostridium difficile infection (CDI). They have made considerable contributions in the study of C difficile pathogenesis, antibiotic predisposition to CDI, and population dynamics as well as the evaluation of new antimicrobial and immunologic therapeutics. Although CDI models have greatly increased understanding of this complicated pathogen, all have limitations in reproducing human disease, notably their inability to generate a truly reflective immune response. This review summarizes the most commonly used models of CDI and discusses their pros and cons and their predictive values in terms of clinical outcomes.

Binaphthyl-1,2,3-triazole peptidomimetics with activity against Clostridium difficile and other pathogenic bacteria

Designed binaphthyl-based, cationic peptidomimetic antimicrobials targeting C. difficile, incorporating a click-derived 1,2,3-triazole ester isostere at the C-terminus MICs of 4 μg mL⁻¹ against three human isolates of C. difficile.

Outpatient parenteral antimicrobial therapy and antimicrobial stewardship: challenges and checklists

Outpatient parenteral antimicrobial therapy (OPAT) has become, for many countries, an established form of healthcare delivery. At the same time, there have been calls to ensure the prudent use of the existing antimicrobial armamentarium. For OPAT, this presents a dilemma. On one hand, stewardship principles look for the most effective agent with minimal collateral effects. In OPAT, whilst the aims of the service are similar, convenience of dosing to optimize early hospital discharge or admission avoidance may take precedence over an agent's spectrum of activity. This brief article aims to highlight the importance and explore the challenges of antimicrobial stewardship in the context of OPAT. Within the UK, the safe and effective use of antimicrobials is modelled around the IDSA/Society for Healthcare Epidemiology of America stewardship practice guidelines with local customization where appropriate. Current UK stewardship practice principles were compared with published good practice recommendations for OPAT to identify how OPAT could support the broader antimicrobial stewardship agenda. It is essential that antimicrobial stewardship teams should understand the challenges faced in the non-inpatient setting and the potential benefits/lower risks associated with avoided admission or shortened hospital stay in this population. Within its limitations, OPAT should practise stewardship principles, including optimization of intravenous to oral switch and the reporting of outcomes, healthcare-associated infections and re-admission rates. OPAT should report to the antimicrobial stewardship team. Ideally the OPAT team should be formally represented within the stewardship framework. A checklist has been proposed to aid OPAT services in ensuring they meet their stewardship agenda.

An international cross-sectional survey of antimicrobial stewardship programmes in hospitals

OBJECTIVES

To report the extent and components of global efforts in antimicrobial stewardship (AMS) in hospitals.

METHODS

An Internet-based survey comprising 43 questions was disseminated worldwide in 2012.

RESULTS

Responses were received from 660 hospitals in 67 countries: Africa, 44; Asia, 50; Europe, 361; North America, 72; Oceania, 30; and South and Central America, 103. National AMS standards existed in 52% of countries, 4% were planning them and 58% had an AMS programme. The main barriers to implementing AMS programmes were perceived to be a lack of funding or personnel, a lack of information technology and prescriber opposition. In hospitals with an existing AMS programme, AMS rounds existed in 64%; 81% restricted antimicrobials (carbapenems, 74.3%; quinolones, 64%; and cephalosporins, 58%); and 85% reported antimicrobial usage, with 55% linking data to resistance rates and 49% linking data to infection rates. Only 20% had electronic prescribing for all patients. A total of 89% of programmes educated their medical, nursing and pharmacy staff on AMS. Of the hospitals, 38% had formally reviewed their AMS programme: reductions were reported by 96% of hospitals for inappropriate prescribing, 86% for broad-spectrum antibiotic use, 80% for expenditure, 71% for healthcare-acquired infections, 65% for length of stay or mortality and 58% for bacterial resistance.

CONCLUSIONS

The worldwide development and implementation of AMS programmes varies considerably. Our results should inform and encourage the further evaluation of this with a view to promoting a worldwide stewardship framework. The prospective measurement of well-defined outcomes of the impact of these programmes remains a significant challenge.

Antibiotic susceptibility of Clostridium difficile is similar worldwide over two decades despite widespread use of broad-spectrum antibiotics: an analysis done at the University Hospital of Zurich

BACKGROUND

Clostridium difficile infection (CDI) remains a major health problem worldwide. Antibiotic use, in general, and clindamycin and ciprofloxacin, in particular, have been implicated in the pathogenesis of CDI. Here, we hypothesized that antibiotics that are highly active in vitro against C. difficile are less frequently associated with CDI than others. The primary goals of our study were to determine if antibiotic susceptibility and CDI are associated and whether the antimicrobial susceptibility of C. difficile changed over the years.

METHODS AND RESULTS

We examined a large panel of C. difficile strains collected in 2006-2008 at the University Hospital of Zurich. We found that the antimicrobial susceptibilities to amoxicillin/clavulanate, piperacillin/tazobactam, meropenem, clindamycin, ciprofloxacin, ceftriaxone, metronidazole and vancomycin were similar to those reported in the literature and that they are similar to those reported in other populations over the last two decades. Antibiotic activity did not prevent CDI. For example, thre use of meropenem, which is highly active against all strains tested, was a clear risk factor for CDI. Most of the antibiotics tested also showed a higher minimum inhibitory concentration distribution than that of EUCAST. All strains were susceptible to metronidazole. One strain was resistant to vancomycin.

CONCLUSIONS

Antibiotic susceptibilities of the collection of C. difficile from the University Hospital of Zurich are similar to those reported by others since the 1980. Patients treated with carbapenems and cephalosporins had the highest risk of developing CDI irrespective of the antimicrobial activity of carbapenems.

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.

Carriage and acquisition rates of Clostridium difficile in hospitalized horses, including molecular characterization, multilocus sequence typing and antimicrobial susceptibility of bacterial isolates

Clostridium difficile has been identified as a significant agent of diarrhoea and enterocolitis in both foals and adult horses. Hospitalization, antibiotic therapy or changes in diet may contribute to the development of C. difficile infection. Horses admitted to a care unit are therefore at greater risk of being colonized. The aim of this study was to investigate the carriage of C. difficile in hospitalized horses and the possible influence of some risk factors in colonization. During a seven-month period, faecal samples and data relating the clinical history of horses admitted to a veterinary teaching hospital were collected. C. difficile isolates were characterized through toxin profiles, cytotoxicity activity, PCR-ribotyping, antimicrobial resistance and multilocus sequence typing (MLST). Ten isolates were obtained with a total of seven different PCR-ribotypes, including PCR-ribotype 014. Five of them were identified as toxinogenic. A high resistance to gentamicin, clindamycin and ceftiofur was found. MLST revealed four different sequencing types (ST), which included ST11, ST26, ST2 and ST15, and phylogenetic analysis showed that most of the isolates clustered in the same lineage. Clinical history suggests that horses frequently harbour toxigenic and non-toxigenic C. difficile and that in most cases they are colonized regardless of the reason for hospitalization; the development of diarrhoea is more unusual.