SYN-004 (ribaxamase), an oral beta-lactamase, mitigates antibiotic-mediated dysbiosis in a porcine gut microbiome model

AIM

To evaluate an antibiotic inactivation strategy to protect the gut microbiome from antibiotic-mediated damage.

METHODS AND RESULTS

SYN-004 (ribaxamase) is an orally delivered beta-lactamase intended to degrade penicillins and cephalosporins within the gastrointestinal tract to protect the microbiome. Pigs (20 kg, n = 10) were treated with ceftriaxone (CRO) (IV, 50 mg kg^-1 , SID) for 7 days and a cohort (n = 5) received ribaxamase (PO, 75 mg, QID) for 9 days beginning the day before antibiotic administration. Ceftriaxone serum levels were not statistically different in the antibiotic-alone and antibiotic + ribaxamase groups, indicating ribaxamase did not alter systemic antibiotic levels. Whole-genome metagenomic analyses of pig faecal DNA revealed that CRO caused significant changes to the gut microbiome and an increased frequency of antibiotic resistance genes. With ribaxamase, the gut microbiomes were not significantly different from pretreatment and antibiotic resistance gene frequency was not increased.

CONCLUSION

Ribaxamase mitigated CRO-mediated gut microbiome dysbiosis and attenuated propagation of the antibiotic resistance genes in pigs.

SIGNIFICANCE AND IMPACT OF THE STUDY

Damage of the microbiome can lead to overgrowth of pathogenic organisms and antibiotic exposure can promote selection for antibiotic-resistant micro-organisms. Ribaxamase has the potential to become the first therapy designed to protect the gut microbiome from antibiotic-mediated dysbiosis and reduce emergence of antibiotic resistance.

Second generation cephalosporin antibiotic prophylaxis and Clostridium difficile infection in hip and knee arthroplasty

Introduction The use of broad spectrum cephalosporin antibiotics has been discouraged by the Department of Health in England because of the link to increased Clostridium difficile infection rates. The aim of this study was to evaluate whether a local protocol that included the use of second generation cephalosporin (cefuroxime) antibiotics as a prophylactic agent was associated with increased risk of C difficile in elective hip and knee arthroplasty patients. Methods A retrospective intention-to-treat study was conducted. An infection control database of all cases of C difficile infection both in hospital and in the community was reviewed and cross-referenced against surgical records. A positive correlation was identified when a C difficile positive sample was documented within eight weeks of arthroplasty surgery. Results Only 1 case (0.02%) of C difficile positive diarrhoea was identified that correlated to the 8-week postoperative period following 4,488 arthroplasty procedures. Conclusions The use of cephalosporin antibiotic prophylaxis in the elective hip and knee arthroplasty setting does not appear to be associated with increased C difficile infection rates, achieving surgical site infection rates that are comparable with the national average.

Update on Antimicrobial Resistance in Clostridium difficile: Resistance Mechanisms and Antimicrobial Susceptibility Testing

Oral antibiotics such as metronidazole, vancomycin and fidaxomicin are therapies of choice for Clostridium difficile infection. Several important mechanisms for C. difficile antibiotic resistance have been described, including the acquisition of antibiotic resistance genes via the transfer of mobile genetic elements, selective pressure in vivo resulting in gene mutations, altered expression of redox-active proteins, iron metabolism, and DNA repair, as well as via biofilm formation. This update summarizes new information published since 2010 on phenotypic and genotypic resistance mechanisms in C. difficile and addresses susceptibility test methods and other strategies to counter antibiotic resistance of C. difficile.

Asymptomatic Carriers Contribute to Nosocomial Clostridium difficile Infection: A Cohort Study of 4508 Patients

BACKGROUND & AIMS

Nosocomial infections with Clostridium difficile present a considerable problem despite numerous attempts by health care workers to reduce risk of transmission. Asymptomatic carriers of C difficile can spread their infection to other patients. We investigated the effects of asymptomatic carriers on nosocomial C difficile infections.

METHODS

We performed a population-based prospective cohort study at 2 university hospitals in Denmark, screening all patients for toxigenic C difficile in the intestine upon admittance, from October 1, 2012, to January 31, 2013. Screening results were blinded to patients, staff, and researchers. Patients were followed during their hospital stay by daily registration of wards and patient rooms. The primary outcomes were rate of C difficile infection in exposed and unexposed patients and factors associated with transmission.

RESULTS

C difficile infection was detected in 2.6% of patients not exposed to carriers and in 4.6% of patients exposed to asymptomatic carriers at the ward level (odds ratio for infection if exposed to carrier, 1.79; 95% confidence interval, 1.16-2.76). Amount of exposure correlated with risk of C difficile infection, from 2.2% in the lowest quartile to 4.2% in the highest quartile of exposed patients (P = .026). Combining the load of exposure to carriers and length of stay seemed to have an additive effect on the risk of contracting C difficile.

CONCLUSIONS

In a population-based prospective cohort study in Denmark, we found that asymptomatic carriers of toxigenic C difficile in hospitals increase risk of infection in other patients.

Evaluating Risk Factors for Clostridium difficile Infection In Stem Cell Transplant Recipients: A National Study

OBJECTIVE

Large-scale studies evaluating risk factors forClostridium difficileinfection (CDI), a leading cause of infectious diarrhea among patients undergoing stem cell transplantation (SCT), are lacking. We have evaluated risk factors for CDI among both autologous SCT (auto-SCT), and allogeneic SCT (allo-SCT) recipients using the National Inpatient Sample (NIS) database provided by the Healthcare Cost and Utilization Project (HCUP).

METHODS

We used patient data obtained from the NIS database for all adult patients admitted for auto- and allo-SCTs from January 2001 to December 2010. We performed multivariate logistic regression analyses to evaluate risk factors of CDI in auto- and allo-SCT patients.

RESULTS

Auto-SCTs constituted 61.5% of all SCTs performed during the study period. Of the 53,072 auto-SCT patients, 5.8% had CDI, whereas 8.5% of 33,189 allo-SCT patients had CDI. Univariate analyses identified age, gender, indication for SCT, radiation as part of the conditioning regimen, respiratory failure, septicemia, lengthy hospital stay, and multiple comorbidities as risk factors for CDI in both subsets. On multivariate analyses for auto-SCT, there was significant correlation between age and the indication for transplant (P=.003), but the indication for either auto- or allo-SCT was not associated with CDI on multivariate analyses. The following factors were found to be associated with CDI: septicemia (auto-SCT odds ratio [OR],=1.64; 95% confidence interval [CI], 1.35–2; and allo-SCT OR, 1.69; 95% CI, 1.36–2.1), male gender (auto-SCT OR, 1.29; 95% CI, 1.09–1.53; and allo-SCT OR, 1.36; 95% CI, 1.18–1.57), lengthy hospital stay (auto-SCT OR, 2.81; 95% CI, 2.29–3.45; and allo-SCT OR, 2.63; 95% CI, 2.15–3.22), and presence of multiple comorbidities (auto-SCT OR, 1.32; 95% CI, 1.11–1.57; and allo-SCT OR, 1.18; 95% CI, 1.0–1.4).

CONCLUSIONS

The prevalence of CDI was higher among patients undergoing allo-SCT. CDI was significantly associated with longer hospital stay, septicemia, and male gender for auto- and allo-SCT recipients. While this analysis did not permit us to directly ascribe the associations to be causative for CDI, it identifies the more vulnerable population for CDI and provides a rationale for the development of more effective approaches to preventing CDI.

Infect Control Hosp Epidemiol2017;38:651–657

Restrictive antibiotic stewardship associated with reduced hospital mortality in gram-negative infection

INTRODUCTION

: Antimicrobial stewardship has an important role in the control of Clostridium difficile infection (CDI) and antibiotic resistance. An important component of UK stewardship interventions is the restriction of broad-spectrum beta-lactam antibiotics and promotion of agents associated with a lower risk of CDI such as gentamicin. While the introduction of restrictive antibiotic guidance has been associated with improvements in CDI and antimicrobial resistance, evidence of the effect on outcome following severe infection is lacking.

METHODS

: In 2008, Glasgow hospitals introduced a restrictive antibiotic guideline. A retrospective before/after study assessed outcome following Gram-negative bacteraemia in the 2-year period around implementation.

RESULTS

: Introduction of restrictive antibiotic guidelines was associated with a reduction in utilization of ceftriaxone and co-amoxiclav and an increase in amoxicillin and gentamicin. Approximately 1593 episodes of bacteremia were included in the study. The mortality over 1-year following Gram-negative bacteraemia was lower in the period following guideline implementation (RR 0.852, P  = 0.045). There was no evidence of a difference in secondary outcomes including ITU admission, length of stay, readmission, recurrence of bacteraemia and need for renal replacement therapy. There was a fall in CDI (RR 0.571, P  = 0.014) and a reduction in bacterial resistance to ceftriaxone and co-amoxiclav but no evidence of an increase in gentamicin resistance after guideline implementation.

CONCLUSION

: Restrictive antibiotic guidelines were associated with a reduction in CDI and bacterial resistance but no evidence of adverse outcomes following Gram-negative bacteraemia. There was a small reduction in one year mortality.

Benefits and unintended consequences of antimicrobial de-escalation: Implications for stewardship programs

Sequential antimicrobial de-escalation aims to minimize resistance to high-value broad-spectrum empiric antimicrobials by switching to alternative drugs when testing confirms susceptibility. Though widely practiced, the effects de-escalation are not well understood. Definitions of interventions and outcomes differ among studies. We use mathematical models of the transmission and evolution of Pseudomonas aeruginosa in an intensive care unit to assess the effect of de-escalation on a broad range of outcomes, and clarify expectations. In these models, de-escalation reduces the use of high-value drugs and preserves the effectiveness of empiric therapy, while also selecting for multidrug-resistant strains and leaving patients vulnerable to colonization and superinfection. The net effect of de-escalation in our models is to increase infection prevalence while also increasing the probability of effective treatment. Changes in mortality are small, and can be either positive or negative. The clinical significance of small changes in outcomes such as infection prevalence and death may exceed more easily detectable changes in drug use and resistance. Integrating harms and benefits into ranked outcomes for each patient may provide a way forward in the analysis of these tradeoffs. Our models provide a conceptual framework for the collection and interpretation of evidence needed to inform antimicrobial stewardship.

Penicillin-susceptible Staphylococcus aureus: susceptibility testing, resistance rates and outcome of infection

BACKGROUND

Staphylococcus aureus (SA) is an important human pathogen that causes both superficial and invasive infections. Penicillin is now rarely used in the treatment of SA infections due to widespread resistance and a concern about the accuracy of existing methods for penicillin susceptibility testing. The aims of the present study were to determine the frequency of penicillin-susceptible SA isolates from blood and wound cultures in Lund, Sweden, and to evaluate methods for penicillin testing in SA. We also wanted to investigate if penicillin-susceptible isolates are associated with higher mortality.

METHODS

Hundred blood culture isolates collected 2008/2009, 140 blood culture isolates from 2014/2015, and 141 superficial wound culture strains from 2015 were examined. Penicillin susceptibility was tested with disk diffusion according to EUCAST guidelines, and results were confirmed with a cloverleaf assay and PCR amplification of the BlaZ gene. Patient data for all bacteraemia cases were extracted from medical records.

RESULTS

The disk diffusion method with assessment of both zone size and zone edge appearance had high accuracy in our study. About 57% of bacteraemia isolates from 2008/2009 were sensitive to penicillin compared to 29% in 2014/2015 (p < .0001). In superficial wound cultures, 21% were penicillin susceptible. There was no difference in co-morbidity or mortality rates between patients with penicillin resistant and penicillin sensitive SA bacteraemia.

CONCLUSION

Disk-diffusion is a simple and reliable method to detect penicillin resistance in SA, and susceptibility rates are significant. Penicillin has many theoretical advantages and should be considered in the treatment of SA bacteraemia when susceptible.

Effectiveness and Safety of Tigecycline Compared with Other Broad-Spectrum Antimicrobials in Abdominal Solid Organ Transplant Recipients with Polymicrobial Intraabdominal Infections

STUDY OBJECTIVE

Because patients with abdominal solid organ transplants (SOTs) are at increased risk of polymicrobial intraabdominal infections (IAIs) following transplantation, the objective of this study was to compare the effectiveness and adverse event profile of tigecycline with those of other broad-spectrum therapies for polymicrobial IAIs in this population.

DESIGN

Retrospective cohort study.

SETTING

Large academic medical center with multiple outpatient clinics.

PATIENTS

A total of 81 adult SOT recipients were included who were treated for confirmed or suspected polymicrobial IAIs from 2007-2012. Of these patients, 27 received tigecycline and 54 received comparator therapy with a broad-spectrum β-lactam (e.g., piperacillin-tazobactam, cefepime, or meropenem) with or without glycopeptide or lipopeptide gram-positive therapy (vancomycin or daptomycin) (comparator group). Patients in the comparator group were matched to tigecycline-treated patients based on transplant type (kidney, combined kidney-pancreas, combined kidney-liver, or solitary pancreas) in a 1:2 ratio (tigecycline-to-other broad-spectrum antibiotics).

MEASUREMENTS AND MAIN RESULTS

Data on patient demographics, comorbidities, and clinical variables were collected and compared by using bivariate analyses. Clinical outcomes-clinical cure, improvement or failure, and disease recurrence-as well as death within 1 year were analyzed by bivariate analyses and logistic regression. Clinical cure was lower in the tigecycline group versus the comparator group (40.7% vs 72.2%, p=0.008), but cure combined with improvement was similar between the two groups (85.2% vs 88.9%, p=0.724). Multiple logistic regression analysis showed that treatment with comparator antibiotics increased the odds of cure (odds ratio [OR] 1.37, 95% confidence interval [CI] 0.15-12.27) and reduced the odds of treatment failure (OR 0.59, 95% CI 0.07-4.55) and death within 1 year (OR 0.79, 95% CI 0.22-2.86); however, patients receiving comparator antibiotics were more likely to have disease recurrence (OR 1.45, 95% CI 0.33-6.36). Patients receiving tigecycline experienced a higher rate of adverse events than those receiving comparator antibiotics (29.6% vs 9.3%, p=0.026).

CONCLUSION

Patients receiving tigecycline were less likely to achieve optimal clinical outcomes and had more adverse events. Alternative regimens should be selected over tigecycline for the treatment of polymicrobial IAIs in abdominal SOT recipients until additional studies are completed to examine its role in this population.

Preferential Use of Nitrofurantoin Over Fluoroquinolones for Acute Uncomplicated Cystitis and Outpatient Escherichia coli Resistance in an Integrated Healthcare System

OBJECTIVES To evaluate changes in outpatient fluoroquinolone (FQ) and nitrofurantoin (NFT) use and resistance among E. coli isolates after a change in institutional guidance to use NFT over FQs for acute uncomplicated cystitis. DESIGN Retrospective preintervention-postintervention study. SETTING Urban, integrated healthcare system. PATIENTS Adult outpatients treated for acute cystitis. METHODS We compared 2 time periods: January 2003-June 2007 when FQs were recommended as first-line therapy, and July 2007-December 2012, when NFT was recommended. The main outcomes were changes in FQ and NFT use and FQ- and NFT-resistant E. coli by time-series analysis. RESULTS Overall, 5,714 adults treated for acute cystitis and 11,367 outpatient E. coli isolates were included in the analysis. After the change in prescribing guidance, there was an immediate 26% (95% CI, 20%-32%) decrease in FQ use (P<.001), and a nonsignificant 6% (95% CI, -2% to 15%) increase in NFT use (P=.12); these changes were sustained over the postintervention period. Oral cephalosporin use also increased during the postintervention period. There was a significant decrease in FQ-resistant E. coli of -0.4% per quarter (95% CI, -0.6% to -0.1%; P=.004) between the pre- and postintervention periods; however, a change in the trend of NFT-resistant E. coli was not observed. CONCLUSIONS In an integrated healthcare system, a change in institutional guidance for acute uncomplicated cystitis was associated with a reduction in FQ use, which may have contributed to a stabilization in FQ-resistant E. coli. Increased nitrofurantoin use was not associated with a change in NFT resistance. Infect Control Hosp Epidemiol 2017;38:461-468.

Clostridium difficile colitis: A clinical review

BACKGROUND

Clostridium difficile colitis is an important cause of morbidity and mortality in the surgical patient. In recent years, Clostridium difficile infections have shown marked increases in frequency, severity, and resistance to standard treatment. With urgent operative interventions and novel endoscopic approaches, pseudomembranous colitis is being seen more commonly in surgical practices.

DATA SOURCES

In this paper, we will review a number of papers from the literature. We will discuss the epidemiology, evaluation and treatment of Clostridium difficile infection. Fulminant colitis may require emergency operation. For the surgical endoscopist, fecal microbiota transplantation restores the gastrointestinal flora, and has been shown to be effective in more than 80% of patients.

CONCLUSION

Clostridium difficile infection is a major cause of healthcare-related diarrhea leading to increased morbidity and mortality in surgical patients. Increases in failure rates and resistance to current treatments are clinical and economic challenges in the healthcare situation.

Australasian Society of Infectious Diseases updated guidelines for the management of Clostridium difficile infection in adults and children in Australia and New Zealand

The incidence of Clostridium difficile infection (CDI) continues to rise, whilst treatment remains problematic due to recurrent, refractory and potentially severe nature of disease. The treatment of C. difficile is a challenge for community and hospital-based clinicians. With the advent of an expanding therapeutic arsenal against C. difficile since the last published Australasian guidelines, an update on CDI treatment recommendations for Australasian clinicians was required. On behalf of the Australasian Society of Infectious Diseases, we present the updated guidelines for the management of CDI in adults and children.

Current and future antimicrobial resistance issues for the Australian pig industry

Antimicrobial use and antimicrobial resistance (AMR) in intensive pig production and its potential impacts to human and animal health are very much under the spotlight, both internationally, and within Australia. While the majority of AMR of medical importance is associated with the exclusive use of antimicrobials in humans, resistance in zoonotic foodborne pathogens such as Salmonella and Campylobacter, and livestock commensal bacteria such as Escherichia coli and Enterococcus spp., is under increased scrutiny. This is primarily due to the current reliance on many of the same drug classes as used in human medicine for treatment and control of bacterial diseases of livestock. Furthermore, the development of multidrug resistance in pathogens such as enterotoxigenic E. coli may drive off-label use of critically important drug classes such as 3rd-generation cephalosporins. This could lead to the emergence and amplification of resistance genes of potential public health significance in both pathogens and commensal bacteria. Livestock-associated and community-associated methicillin-resistant Staphylococcus aureus has also recently been detected in Australian pigs as a result of human-to-animal transmission and are a potential public health issue for in-contact piggery workers. Australia is in a unique position compared with many of its international trading partners due to its isolation, ban on importation of livestock and conservative approach to antimicrobial registration, including reservation of the fluoroquinolone class for use in humans and companion animals only. Cross-sectional AMR surveys of pathogens and commensals in healthy pigs have identified only low frequency of resistance to critically important drug classes. Nevertheless, resistance to critically important antimicrobials has emerged and careful antimicrobial stewardship is required to ensure that these low levels do not increase. In this report, we review AMR of significance to the Australian pig industry and identify potential prevention and control measures.

Comparison of Clostridium difficile Ribotypes Circulating in Australian Hospitals and Communities

Clostridium difficile infection (CDI) is becoming less exclusively a health care-associated CDI (HA-CDI). The incidence of community-associated CDI (CA-CDI) has increased over the past few decades. It has been postulated that asymptomatic toxigenic C. difficile (TCD)-colonized patients may play a role in the transfer of C. difficile between the hospital setting and the community. Thus, to investigate the relatedness of C. difficile across the hospital and community settings, we compared the characteristics of symptomatic and asymptomatic host patients and the pathogens from these patients in these two settings over a 3-year period. Two studies were simultaneously conducted; the first study enrolled symptomatic CDI patients from two tertiary care hospitals and the community in two Australian states, while the second study enrolled asymptomatic TCD-colonized patients from the same tertiary care hospitals. A total of 324 patients (96 with HA-CDI, 152 with CA-CDI, and 76 colonized with TCD) were enrolled. The predominant C. difficile ribotypes isolated in the hospital setting corresponded with those isolated in the community, as it was found that for 79% of the C. difficile isolates from hospitals, an isolate with a matching ribotype was isolated in the community, suggesting that transmission between these two settings is occurring. The toxigenic C. difficile strains causing symptomatic infection were similar to those causing asymptomatic infection, and patients exposed to antimicrobials prior to admission were more likely to develop a symptomatic infection (odds ratio, 2.94; 95% confidence interval, 1.20 to 7.14). Our findings suggest that the development of CDI symptoms in a setting without establishment of hospital epidemics with binary toxin-producing C. difficile strains may be driven mainly by host susceptibility and exposure to antimicrobials, rather than by C. difficile strain characteristics.

The burden of healthcare-associated Clostridium difficile infection in a non-metropolitan setting

OBJECTIVE

Healthcare-associated Clostridium difficile infection (HCA-CDI) remains a major cause of morbidity and mortality in industrialized countries. However, few data exist on the burden of HCA-CDI in multi-site non-metropolitan settings. This study examined the introduction of an antimicrobial stewardship programme (ASP) in relation to HCA-CDI rates, and the effect of HCA-CDI on length of stay (LOS) and hospital costs.

METHODS

A comparative before-and-after intervention study of patients aged ≥16 years with HCA-CDI from December 2010 to April 2016 across the nine hospitals of a non-metropolitan health district in New South Wales, Australia was undertaken. The intervention comprised a multi-site ASP supported by a clinical decision support system, with subsequent introduction of email feedback of HCA-CDI cases to admitting medical officers.

MAIN OUTCOME MEASURES

HCA-CDI rates, comparative LOS and hospital costs, prior use of antimicrobials and proton pump inhibitors, and appropriateness of CDI treatment.

RESULTS

HCA-CDI rates rose from 3.07 to 4.60 cases per 10,000 occupied bed-days pre-intervention, and remained stable at 4 cases per 10,000 occupied bed-days post-intervention (P=0.24). Median LOS (17 vs six days; P<0.01) and hospital costs (AU$19,222 vs $7861; P<0.01) were significantly greater for HCA-CDI cases (N=91) than for matched controls (N=172). Half of the patients with severe HCA-CDI (4/8) did not receive initial appropriate treatment (oral vancomycin).

CONCLUSIONS

HCA-CDI placed a significant burden on the regional and rural health service through increased LOS and hospital costs. Interventions targeting HCA-CDI could be employed to consolidate the effects of ASPs.

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.

Back to the Future: Penicillin-Susceptible Staphylococcus aureus

BACKGROUND

Widespread penicillin usage rapidly resulted in the emergence of penicillin resistance in Staphylococcus aureus. However, new data suggest that penicillin susceptibility may be in a period of renaissance. The objective of our study was to quantify penicillin resistance in methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia.

METHODS

We retrospectively reviewed all adult MSSA bacteremia from April 2010 to April 2015 at the McGill University Health Centre (Montreal, QC, Canada). Susceptibility to penicillin, erythromycin, clindamycin, and trimethoprim-sulfamethoxazole (TMP-SMX) was determined in accordance with the Clinical & Laboratory Standards Institute guidelines.

RESULTS

There were 324 unique episodes of MSSA bacteremia. Ninety (28%) isolates were susceptible to penicillin, 229 (71%) to erythromycin, 239 (74%) to clindamycin, and 317 (98%) to TMP-SMX. Isolates that were penicillin resistant were more likely to also be resistant to other antibiotics, but a statistically significant association was apparent only for erythromycin resistance (76/234, 32.2% vs 19/90, 21.1%, P = .04). The median age of patients was 67.5 years (interquartile range 52-78) and overall in-hospital 30-day mortality was 16.3% (53 deaths). After adjustment for patient age, there was no association between penicillin resistance and either intensive care unit admission or death.

CONCLUSION

More than one-quarter of patients with MSSA bacteremia potentially could be treated with parenteral penicillin, which may offer pharmacokinetic advantages over other beta-lactam drugs and potentially improved outcomes.

Variability in antibiotic use across Ontario acute care hospitals

BACKGROUND

Antibiotic stewardship is a required organizational practice for Canadian acute care hospitals, yet data are scarce regarding the quantity and composition of antibiotic use across facilities. We sought to examine the variability, and risk-adjusted variability, in antibiotic use across acute care hospitals in Ontario, Canada's most populous province.

METHODS

Antibiotic purchasing data from IMS Health, previously demonstrated to correlate strongly with internal antibiotic dispensing data, were acquired for 129 Ontario hospitals from January to December 2014 and linked to patient day (PD) denominator data from administrative datasets. Hospital variation in DDDs/1000 PDs was determined for overall antibiotic use, class-specific use and six practices of clinical or ecological significance. Multivariable risk adjustment for hospital and patient characteristics was used to compare observed versus expected utilization.

RESULTS

There was 7.4-fold variability in the quantity of antibiotic use across the 129 acute care hospitals, from 253 to 1873 DDDs/1000 PDs. Variation was evident within hospital subtypes, exceeded that explained by hospital and patient characteristics, and included wide variability in proportion of broad-spectrum antibiotics (IQR 36%-48%), proportion of fluoroquinolones among respiratory antibiotics (IQR 40%-62%), proportion of ciprofloxacin among urinary anti-infectives (IQR 44%-60%), proportion of antibiotics with highest risk for Clostridium difficile (IQR 29%-40%), proportion of 'reserved-use' antibiotics (IQR 0.8%-3.5%) and proportion of anti-pseudomonal antibiotics among antibiotics with Gram-negative coverage (IQR 26%-40%).

CONCLUSIONS

There is extensive variability in antibiotic use, and risk-adjusted use, across acute care hospitals. This could motivate, focus and benchmark antibiotic stewardship efforts.

Antimicrobial Stewardship: A Call to Action for Surgeons

Despite current antimicrobial stewardship programs (ASPs) being advocated by infectious disease specialists and discussed by national and international policy makers, ASPs coverage remains limited to only certain hospitals as well as specific service lines within hospitals. The ASPs incorporate a variety of strategies to optimize antimicrobial agent use in the hospital, yet the exact set of interventions essential to ASP success remains unknown. Promotion of ASPs across clinical practice is crucial to their success to ensure standardization of antimicrobial agent use within an institution. To effectively accomplish this standardization, providers who actively engage in antimicrobial agent prescribing should participate in the establishment and support of these programs. Hence, surgeons need to play a major role in these collaborations. Surgeons must be aware that judicious antibiotic utilization is an integral part of any stewardship program and necessary to maximize clinical cure and minimize emergence of antimicrobial resistance. The battle against antibiotic resistance should be fought by all healthcare professionals. If surgeons around the world participate in this global fight and demonstrate awareness of the major problem of antimicrobial resistance, they will be pivotal leaders. If surgeons fail to actively engage and use antibiotics judiciously, they will find themselves deprived of the autonomy to treat their patients.

Antimicrobial Stewardship and Environmental Decontamination for the Control of Clostridium difficile Transmission in Healthcare Settings

We implement an agent-based model for Clostridium difficile transmission in hospitals that accounts for several processes and individual factors including environmental and antibiotic heterogeneity in order to evaluate the efficacy of various control measures aimed at reducing environmental contamination and mitigating the effects of antibiotic use on transmission. In particular, we account for local contamination levels that contribute to the probability of colonization and we account for both the number and type of antibiotic treatments given to patients. Simulations illustrate the relative efficacy of several strategies for the reduction of nosocomial colonizations and nosocomial diseases.

Antibiotics as deep modulators of gut microbiota: between good and evil

The recent increase in our knowledge of human gut microbiota has changed our view on antibiotics. Antibiotics are, indeed, no longer considered only beneficial, but also potentially harmful drugs, as their abuse appears to play a role in the pathogenesis of several disorders associated with microbiota impairment (eg, Clostridium difficile infection or metabolic disorders). Both drug-related factors (such as antibiotic class, timing of exposure or route of administration) and host-related factors appear to influence the alterations of human gut microbiota produced by antibiotics. Nevertheless, antibiotics are nowadays considered a reliable therapy for some non-communicable disorders, including IBS or hepatic encephalopathy. Moreover, some antibiotics can also act positively on gut microbiota, providing a so-called 'eubiotic' effect, by increasing abundance of beneficial bacteria. Therefore, antibiotics appear to change, for better or worse, the nature of several disorders, including IBS, IBD, metabolic disorders or liver disease. This reviews aims to address the potential of antibiotics in the development of major non-communicable disorders associated with the alteration of gut microbiota and on newly discovered therapeutic avenues of antibiotics beyond the cure of infectious diseases.

The Use of Systemic and Topical Fluoroquinolones

Appropriate prescribing practices for fluoroquinolones, as well as all antimicrobial agents, are essential as evolving resistance patterns are considered, additional treatment indications are identified, and the toxicity profile of fluoroquinolones in children has become better defined. Earlier recommendations for systemic therapy remain; expanded uses of fluoroquinolones for the treatment of certain infections are outlined in this report. Prescribing clinicians should be aware of specific adverse reactions associated with fluoroquinolones, and their use in children should continue to be limited to the treatment of infections for which no safe and effective alternative exists or in situations in which oral fluoroquinolone treatment represents a reasonable alternative to parenteral antimicrobial therapy.

Influence of antibiotics and case exposure on hospital-acquired Clostridium difficile infection independent of illness severity

BACKGROUND

Previous studies of the association between antibiotic exposure and risk of hospital-acquired Clostridium difficile-associated infection (CDI) have not fully accounted for patient severity of illness, and competing risks.

AIM

To determine the potential effects of interventions on hospital-acquired CDI risk.

METHODS

All adults admitted to a teaching hospital between 2004 and 2014 for more than two days were included. Exposures to all antibiotics and cases of CDI were determined. Patients were followed until discharge from hospital, death, or acquisition of hospital-acquired CDI (defined as positive toxin assay in unformed stool >2 days following admission). Multivariable proportional hazards competing-risks modelling with time-dependent covariates was used, accounting for patient severity of illness using the Escobar model.

FINDINGS

In all, 208,104 patients were studied. Hospital-acquired CDI risk was 0.46 events per 1000 patient-days, decreasing significantly during the study period. Compared to the 5^th percentile hospital death risk (0.02%), patients with a 50% risk of death in hospital had an adjusted hazard ratio (aHR) of hospital-acquired CDI of 5.5. Exposure to some antibiotics significantly increased hospital-acquired CDI risk, being highest for carbapenems (aHR: 1.47 after one week of continuous exposure) and intravenous vancomycin (aHR: 1.53). On the ward, sharing a room with other patients newly diagnosed with CDI significantly increased the risk of subsequent disease (aHR: 1.16 on CDI diagnosis day).

CONCLUSION

The primary determinant of hospital-acquired CDI was patient severity of illness. Exposure to both antibiotics and other patients with CDI significantly increased the subsequent risk of hospital-acquired CDI but this risk was small relative to patient severity of illness.

Role of cephalosporins in the era of Clostridium difficile infection

The incidence of Clostridium difficile infection (CDI) in Europe has increased markedly since 2000. Previous meta-analyses have suggested a strong association between cephalosporin use and CDI, and many national programmes on CDI control have focused on reducing cephalosporin usage. Despite reductions in cephalosporin use, however, rates of CDI have continued to rise. This review examines the potential association of CDI with cephalosporins, and considers other factors that influence CDI risk. EUCLID (the EUropean, multicentre, prospective biannual point prevalence study of CLostridium difficile Infection in hospitalized patients with Diarrhoea) reported an increase in the annual incidence of CDI from 6.6 to 7.3 cases per 10 000 patient bed-days from 2011-12 to 2012-13, respectively. While CDI incidence and cephalosporin usage varied widely across countries studied, there was no clear association between overall cephalosporin prescribing (or the use of any particular cephalosporin) and CDI incidence. Moreover, variations in the pharmacokinetic and pharmacodynamic properties of cephalosporins of the same generation make categorization by generation insufficient for predicting impact on gut microbiota. A multitude of additional factors can affect the risk of CDI. Antibiotic choice is an important consideration; however, CDI risk is associated with a range of antibiotic classes. Prescription of multiple antibiotics and a long duration of treatment are key risk factors for CDI, and risk also differs across patient populations. We propose that all of these are factors that should be taken into account when selecting an antibiotic, rather than focusing on the exclusion of individual drug classes.

[Diagnostic workup and therapy of infectious diarrhea. Current standards]

Infectious diarrhea is very common; its severity ranges from uncomplicated, self-limiting courses to potentially life-threatening disease. A rapid diagnostic workup providing detailed information on the suspected pathogen should be performed only in patients at risk, analyzing one single stool sample for Salmonella, Shigella, Campylobacter, and Norovirus. In the presence of risk factors, such as a history of antibiotic exposure within the last 3 months, testing for Clostridium difficile should be performed. Immunocompetent patients do not require specific antibiotic therapy. Exceptions exist in patients with severe comorbidities, immunodeficiency, fever/SIRS, and in patients with Shigella or C. difficile infection. Empirical antibiotic treatment should be considered in patients with fever and/or bloody diarrhea and in patients at risk. In patients with traveler's diarrhea, microbiological diagnosis is required only in patients with fever, bloody diarrhea, prolonged course of disease (more than 5 days), severe clinical course with hypotension or dehydration, and during outbreaks. In these patients one single fecal sample should be collected for stool cultures of Campylobacter, Shigella, and Salmonella, as well as microscopic examination for amoebiasis and Giardiasis. The main therapeutic measure for infectious diarrhea is sufficient oral rehydration. As in community-acquired diarrhea, azithromycin or ciprofloxacin are recommended-taking into account local antimicrobial resistance in the country of travel and possible side effects.

Clostridium difficile Infection in Production Animals and Avian Species: A Review

Clostridium difficile is the leading cause of antibiotic-associated diarrhea and colitis in hospitalized humans. Recently, C. difficile infection (CDI) has been increasingly recognized as a cause of neonatal enteritis in food animals such as pigs, resulting in stunted growth, delays in weaning, and mortality, as well as colitis in large birds such as ostriches. C. difficile is a strictly anaerobic spore-forming bacterium, which produces two toxins A (TcdA) and B (TcdB) as its main virulence factors. The majority of strains isolated from animals produce an additional binary toxin (C. difficile transferase) that is associated with increased virulence. C. difficile is ubiquitous in the environment and has a wide host range. This review summarizes the epidemiology, clinical presentations, risk factors, and laboratory diagnosis of CDI in animals. Increased awareness by veterinarians and animal owners of the significance of clinical disease caused by C. difficile in livestock and avians is needed. Finally, this review provides an overview on methods for controlling environmental contamination and potential therapeutics available.

Epidemiology and Risk Factors for Community-Associated Clostridium difficile Infection: A Narrative Review

Clostridium difficile infection (CDI) was once considered a primarily nosocomial concern. Emerging evidence from the last 20 years has highlighted a drastic shift in the known epidemiology of CDI, with disease outside of hospitals apparently occurring more frequently and causing severe disease in populations that were thought to be at low risk. This narrative review summarises potential pathways for infection outside of the hospital environment and highlights likely routes of transmission. Further, evidence is presented on potential risk factors for development of disease. Understanding the epidemiology of CDI outside of hospitals is essential to the ability to prevent and control disease in vulnerable populations.

Effects of a Syndrome-Specific Antibiotic Stewardship Intervention for Inpatient Community-Acquired Pneumonia

A syndrome-specific intervention to improve the management of community-acquired pneumonia in non-intensive care settings was associated with shorter treatment durations, less fluoroquinolone use, and a reduction in use of low-yield diagnostic tests.

Background. Syndrome-specific interventions are a recommended approach to antibiotic stewardship, but additional data are needed to understand their potential impact. We implemented an intervention to improve the management of inpatient community-acquired pneumonia (CAP) and evaluated its effects on antibiotic and resource utilization.

Methods. A stakeholder group developed and implemented a clinical practice guideline and order set for inpatient, non-intensive care unit CAP recommending a short course (5 days) of a fluoroquinolone-sparing antibiotic regimen in uncomplicated cases. Unless there was suspicion for complications or resistant pathogens, chest computed tomography (CT) and sputum cultures were discouraged. This was a retrospective preintervention postintervention study of patients hospitalized for CAP before (April 15, 2008–May 31, 2009) and after (July 1, 2011–July 31, 2012) implementation of the guideline. The primary comparison was the difference in duration of therapy during the baseline and intervention periods. Secondary outcomes included changes in use of levofloxacin, CT scans, and sputum culture.

Results. One hundred sixty-six and 84 cases during the baseline and intervention periods, respectively, were included. From the baseline to intervention period, the median duration of therapy decreased from 10 to 7 days (P < .0001). Prescription of levofloxacin at discharge decreased from 60% to 27% of cases (P < .0001). Use of chest CT and sputum culture decreased from 47% to 32% of cases (P = .02) and 51% to 31% of cases (P = .03), respectively. The frequency of clinical failure between the 2 periods was similar.

Conclusions. A syndrome-specific intervention for inpatient CAP was associated with shorter treatment durations and reductions in use of fluoroquinolones and low-yield diagnostic tests.

Clostridium difficile Infection in Special High-Risk Populations

Antibiotic use continues to be the most important risk factor for the development of Clostridium difficile infection (CDI) through disruption of the indigenous microbiota of the colon. This factor, together with environmental contamination, makes hospital and other healthcare facilities the perfect breeding ground for the infection. Several groups of patients are exposed to the hospital environment and, at the same time, affected by conditions that can make CDI more prevalent, more severe or make it present a different clinical picture. The list of such conditions appears too extensive to be reviewed in a single article. Nevertheless, several groups, including the critically ill, oncological patients, solid organ and hematopoietic transplant recipients, patients with inflammatory bowel disease, patients with kidney disease and pregnant women, have generated more attention and have been studied in more detail. On the other hand, pediatric patients constitute a controversial group because the large number of asymptomatic carriers makes interpretation of clinical findings and diagnostic tests difficult, as is the development of an appropriate approach to treatment. We present an in-depth discussion of CDI in these high-risk populations and we also review the issue of CDI in pediatric patients.

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.

Ridinilazole: a novel therapy for Clostridium difficile infection

Clostridium difficile infection (CDI) is the leading cause of infectious healthcare-associated diarrhoea. Recurrent CDI increases disease morbidity and mortality, posing a high burden to patients and a growing economic burden to the healthcare system. Thus, there exists a significant unmet and increasing medical need for new therapies for CDI. This review aims to provide a concise summary of CDI in general and a specific update on ridinilazole (formerly SMT19969), a novel antibacterial currently under development for the treatment of CDI. Owing to its highly targeted spectrum of activity and ability to spare the normal gut microbiota, ridinilazole provides significant advantages over metronidazole and vancomycin, the mainstay antibiotics for CDI. Ridinilazole is bactericidal against C. difficile and exhibits a prolonged post-antibiotic effect. Furthermore, treatment with ridinilazole results in decreased toxin production. A phase 1 trial demonstrated that oral ridinilazole is well tolerated and specifically targets clostridia whilst sparing other faecal bacteria. Phase 2 and 3 trials will hopefully further our understanding of the clinical utility of ridinilazole for the treatment of CDI.

Reducing co-administration of proton pump inhibitors and antibiotics using a computerized order entry alert and prospective audit and feedback

Background

Antibiotics and proton pump inhibitors (PPIs) are associated with Clostridium difficile infection (CDI). Both a computer order entry alert to highlight this association as well as antimicrobial stewardship directed prospective audit and feedback represent novel interventions to reduce the co-administration of antibiotics and PPIs among hospitalized patients.

Methods

Consecutive patients admitted to two General Internal Medicine wards from October 1, 2010 until March 31, 2013 at a teaching hospital in Toronto, Ontario, Canada were evaluated. The baseline observation period was followed by the first phase, which involved the creation of a computerized order entry alert that was triggered when either a PPI or an antibiotic was ordered in the presence of the other. The second phase consisted of the introduction of an antibiotic stewardship-initiated prospective audit and feedback strategy. The primary outcome was the co-administration of antibiotics and PPIs during each phase.

Results

This alert led to a significant reduction in the co-administration of antibiotics and PPIs adjusted for month and secular trends, expressed as days of therapy per 100 patient days (4.99 vs. 3.14, p < 0.001) The subsequent introduction of the antibiotic stewardship program further reduced the co-administration (3.14 vs. 1.80, p <0.001). No change was observed in adjusted monthly CDI rates per 100 patient care days between the baseline and alert cohorts (0.12 vs. 0.12, p = 0.99) or the baseline and antibiotic stewardship phases (0.12 vs. 0.13, p = 0.97).

Conclusions

Decreasing the co-administration of PPIs and antibiotics can be achieved using a simple automatic alert followed by prospective audit and feedback.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1679-8) contains supplementary material, which is available to authorized users.

Comparison of the safety, tolerability, and pharmacokinetics of fidaxomicin in healthy Japanese and caucasian subjects

Background and Objectives

Fidaxomicin treatment of Clostridium difficile infection is known to produce minimal systemic exposure, as the antibacterial (antibiotic) remains primarily in the gut. In this randomized, double-blind, placebo-controlled study, the safety, tolerability, and pharmacokinetics of single and multiple ascending doses of fidaxomicin were evaluated in healthy Japanese and Caucasian subjects.

Methods

Thirty-six healthy subjects were randomly assigned in a 3:1 ratio to receive either fidaxomicin or placebo. Cohort 1 (100 mg) and Cohort 2 (200 mg) comprised 12 Japanese subjects each and Cohort 3 (200 mg) comprised 12 Caucasian subjects. Subjects received a single dose of the study drug on Day 1 and received multiple doses for 10 days after a wash-out period.

Results

After multiple 200 mg dosing of fidaxomicin, both mean maximum plasma concentrations (C_max) in Japanese (8.7 ± 5.3 ng/mL) and Caucasian (7.0 ± 3.7 ng/mL) subjects and the area under the concentration–time curve (AUC) were higher in Japanese subjects (58.5 ± 36.7 ng·h/mL) than in Caucasian subjects (37.6 ± 15.7 ng·h/mL), although variation in both groups was large. The mean fecal concentrations of fidaxomicin in Japanese and Caucasian subjects were 2669 and 2181 μg/g, respectively. The possibly study drug-related adverse events were diarrhea (n = 1), feeling hot (n = 1), and hypersomnia (n = 2), which were mild in severity.

Conclusions

In both Japanese and Caucasian subjects, fidaxomicin demonstrated similarly minimal systemic absorption, and was mainly excreted in feces. Fidaxomicin was safe and well-tolerated in all subjects.

Epidemiology, Diagnosis, and Management of Clostridium difficile Infection in Patients with Inflammatory Bowel Disease

Clostridium difficile infection (CDI) is a major source of morbidity and mortality for the U.S. health care system and frequently complicates the course of inflammatory bowel disease (IBD). Patients with IBD are more likely to be colonized with C. difficile and develop active infection than the general population. They are also more likely to have severe CDI and develop subsequent complications such as IBD flare, colectomy, or death. Even after successful initial treatment and recovery, recurrent CDI is common. Management of CDI in IBD is fraught with diagnostic and therapeutic challenges because the clinical presentations of CDI and IBD flare have considerable overlap. Fecal microbiota transplantation can be successful in curing recurrent CDI when other treatments have failed, but may also trigger IBD flare and this warrants caution. New experimental treatments including vaccines, monoclonal antibodies, and nontoxigenic strains of C. difficile offer promise but are not yet available for clinicians. A better understanding of the complex relationship between the gut microbiota, CDI, and IBD is needed.

Prevention of Clostridium difficile Infection: A Systematic Survey of Clinical Practice Guidelines

BACKGROUND Clostridium difficile infection (CDI) is the most common cause of hospital-acquired infectious diarrhea. OBJECTIVE To analyze the methodological quality, content, and supporting evidence among clinical practice guidelines (CPGs) on CDI prevention. DESIGN AND SETTING We searched medical databases and gray literature for CPGs on CDI prevention published January 2004-January 2015. Three reviewers independently screened articles and rated CPG quality using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) instrument, composed of 23 items, rated 1-7, within 6 domains. We reported each domain score as a percentage of its maximum possible score and standardized range. We summarized recommendations, extracted their supporting articles, and rated individually the level of evidence using the Oxford Centre for Evidence-Based Medicine Levels of Evidence. RESULTS Of 2,578 articles screened, 5 guidelines met inclusion criteria. Median AGREE II scores and interquartile ranges were: clarity of presentation, 75.9% (75.9%-79.6%); scope and purpose, 74.1% (68.5%-85.2%); editorial independence, 63.9% (47.2%-66.7%); applicability, 43.1% (19.4%-55.6%); stakeholder involvement, 40.7% (38.9%-44.4%); and rigor of development, 18.1% (17.4%-35.4%). CPGs addressed several common strategies for CDI prevention, including antibiotic stewardship, hypochlorite solutions, probiotic prophylaxis, and bundle strategies. Recommendations were often not consistent with evidence, and most were based on low-level studies. CONCLUSION CPGs did not adhere well to AGREE II reporting standards. Furthermore, there was limited transparency in moving from evidence to recommendations. CDI prevention CPGs need to better adhere to AGREE-II and be transparent in moving from evidence to recommendations, and recommendations need to be consistent with available evidence. Infect Control Hosp Epidemiol 2016;37:901-908.

Clostridium difficile Infection

Clostridium difficile is an anaerobic, Gram-positive, spore-forming, toxin-secreting bacillus that has long been recognized to be the most common etiologic pathogen of antibiotic-associated diarrhea. C. difficile infection (CDI) is now the most common cause of health care-associated infections in the United States and accounts for 12% of these infections (Magill SS et al., N Engl J Med370:1198-1208, 2014). Among emerging pathogens of public health importance in the United States, CDI has the highest population-based incidence, estimated at 147 per 100,000 (Lessa FC et al., N Engl J Med372:825-834, 2015). In a report on antimicrobial resistance, C. difficile has been categorized by the Centers for Disease Control and Prevention as one of three "urgent" threats (http://www.cdc.gov/drugresistance/threat-report-2013/). Although C. difficile was first described in the late 1970s, the past decade has seen the emergence of hypertoxigenic strains that have caused increased morbidity and mortality worldwide. Pathogenic strains, host susceptibility, and other regional factors vary and may influence the clinical manifestation and approach to intervention. In this article, we describe the global epidemiology of CDI featuring the different strains in circulation outside of North America and Europe where strain NAP1/027/BI/III had originally gained prominence. The elderly population in health care settings has been disproportionately affected, but emergence of CDI in children and healthy young adults in community settings has, likewise, been reported. New approaches in management, including fecal microbiota transplantation, are discussed.

Pilin Vaccination Stimulates Weak Antibody Responses and Provides No Protection in a C57Bl/6 Murine Model of Acute Clostridium difficile Infection

Clostridium difficile is the leading cause of nosocomial infections in the United States, adding billions of dollars per year to health care costs. A vaccine targeted against the bacterium would be extremely beneficial in decreasing the morbidity and mortality caused by C. difficile-associated disease; a vaccine directed against a colonization factor would hinder the spread of the bacterium as well as prevent disease. Type IV pili (T4Ps) are extracellular appendages composed of protein monomers called pilins. They are involved in adhesion and colonization in a wide variety of bacteria and archaea, and are putative colonization factors in C. difficile. We hypothesized that vaccinating mice with pilins would lead to generation of anti-pilin antibodies, and would protect against C. difficile challenge. We found that immunizing C57Bl/6 mice with various pilins, whether combined or as individual proteins, led to low anti-pilin antibody titers and no protection upon C. difficile challenge. Passive transfer of anti-pilin antibodies led to high serum anti-pilin IgG titers, but to undetectable fecal anti-pilin IgG titers and did not protect against challenge. The low antibody titers observed in these experiments may be due to the particular strain of mice used. Further experiments, possibly with a different animal model of C. difficile infection, are needed to determine if an anti-T4P vaccine would be protective against C. difficile infection.

[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.