Do fluoroquinolones predispose patients to Clostridium difficile associated disease? A review of the evidence

Healthcare-Associated Infections and the Use of Antibiotics in German Hospitals

BACKGROUND

A national point prevalence survey (PPS) of healthcare-associated infections (HAI) and antibiotic use (AU) was carried out in Germany in 2022 in the framework of the European PPS conducted by the European Centre for Disease Prevention and Control (ECDC). The objective was to determine the prevalence of HAI and AU in German hospitals and to compare the obtained values with those of the most recent previous PPS, which was carried out in 2016.

METHODS

The German National Reference Center for the Surveillance of Nosocomial Infections was entrusted with the organization of the PPS of 2022. As recommended by the ECDC, each hospital in a representative sample of 50 hospitals was invited to participate, and all other interested hospitals in Germany were also able to participate if desired. The data were collected by specially trained hospital staff in May, June, and July 2022. The definitions and methods put forth by the ECDC were used.

RESULTS

Data from 66 586 patients in 252 hospitals were included. The prevalence of HAI in all participating hospitals was 4.9%, and that of AU was 26.9%. The HAI and AU prevalences were essentially unchanged in comparison to 2016. The most common types of HAI were surgical site infection (23.5%), lower respiratory tract infection (21.6%), and urinary tract infection (19.0%).

CONCLUSION

HAI were just as frequent in 2022 as in 2016, affecting approximately one in twenty hospitalized patients on any given day.

Fluoroquinolone-associated adverse events of interest among hospitalized veterans affairs patients with community-acquired pneumonia who were treated with a fluoroquinolone: A focus on tendonitis, Clostridioides difficile infection, and aortic aneurysm

STUDY OBJECTIVE

The objectives of this study were to (i) quantify the incidence of three concerning fluoroquinolone adverse events of interest (FQAEI, i.e., adverse tendon event (TE), clostridioides difficile infection (CDI), and aortic aneurysm/dissection (AAD)), (ii) identify the patient-level factors that predict these events, and (iii) develop clinical risk scores to estimate the predicted probabilities of each FQAEI based on patient-level covariates available on clinical presentation.

DESIGN

Retrospective cohort study.

SETTING

Upstate New York Veterans' Healthcare Administration from 2011 to 2016.

PATIENTS

Hospitalized patients with community-acquired pneumonia receiving care in the Upstate New York Veterans' Healthcare Administration from 2011 to 2016.

INTERVENTION

N/A.

MEASUREMENTS

The outcomes of interest for this study were the occurrence of TE, CDI, and AAD. We also evaluated a composite of these three outcomes, FQAEI.

MAIN RESULTS

The study population consisted of 1071 patients. The overall incidence of FQAEI, TE, AAD, and CDI was 6.5%, 1.8%, 4.5%, and 0.3%, respectively. For each outcome evaluated, the probability of the event of interest was predicted by the presence of certain comorbidities, previous healthcare exposure, choice of specific FQ antibiotic, or therapy duration. Concomitant steroids, pneumonia in preceding 180 days, and creatinine clearance <30 mL/min predicted FQAEI.

CONCLUSIONS

Individual frequencies of three important FQAEIs were quantified, and risk scores were developed to estimate the probabilities of experiencing these events to help clinicians individualize treatment decisions for patients and reduce the potential risks of select FQAEIs.

Single-Centre Retrospective Audit of Clostridium difficile Infections Post Ileostomy Reversal

Background Clostridium difficile (C. difficile) infection can have serious implications on patient outcomes, especially post ileostomy reversal. The symptoms can range from asymptomatic/mild to severe, with significant morbidity or mortality. Thus far, no study has been published to determine the role and impact of preoperative C. difficile testing prior to ileostomy reversal. The aim of this audit was to identify risk factors for the development of post-ileostomy reversal C. difficile infection and provide further improvements and direction for future research. Methods All patients undergoing ileostomy reversal at the General Surgery Department at Sir Charles Gairdner Hospital, a tertiary centre in Perth, Western Australia, were retrospectively identified between January 2019 and June 2021. Demographics and key data points, such as specific types of antibiotic usage, were extracted from patient notes and analysed using IBM SPSS Statistics for Windows, version 27 (released 2020; IBM Corp., Armonk, New York, United States). Results Sixty-nine patients were identified in the audit period, with 8.70% of patients testing positive for C. difficile infection post ileostomy reversal. At the index ileostomy formation operation, postoperative use of quinolone antibiotics was statistically associated with an increased risk of developing C. difficile on ileostomy reversal (odds ratio (OR) = 15.25, confidence interval (CI) 95%, p = 0.035). Intraoperative nitroimidazole use was statistically associated with a reduced risk of C. difficile infection on ileostomy reversal (OR = 0.16, CI 95%, p = 0.045). Patients who had diverticulitis as their underlying disease pathology were 10 times more likely to develop C. difficile infection post ileostomy reversal, although this finding was not statistically significant in our study. Conclusion Several risk factors were identified, such as the use of quinolone antibiotics or having underlying diverticulitis as causes for ileostomy formation. The results from this audit provides further direction in designing further research studies into the role and impact of C. difficile testing and treatment in the perioperative period around ileostomy reversal.

Overview of Side-Effects of Antibacterial Fluoroquinolones: New Drugs versus Old Drugs, a Step Forward in the Safety Profile?

Antibacterial fluoroquinolones (FQs) are frequently used in treating infections. However, the value of FQs is debatable due to their association with severe adverse effects (AEs). The Food and Drug Administration (FDA) issued safety warnings concerning their side-effects in 2008, followed by the European Medicine Agency (EMA) and regulatory authorities from other countries. Severe AEs associated with some FQs have been reported, leading to their withdrawal from the market. New systemic FQs have been recently approved. The FDA and EMA approved delafloxacin. Additionally, lascufloxacin, levonadifloxacin, nemonoxacin, sitafloxacin, and zabofloxacin were approved in their origin countries. The relevant AEs of FQs and their mechanisms of occurrence have been approached. New systemic FQs present potent antibacterial activity against many resistant bacteria (including resistance to FQs). Generally, in clinical studies, the new FQs were well-tolerated with mild or moderate AEs. All the new FQs approved in the origin countries require more clinical studies to meet FDA or EMA requirements. Post-marketing surveillance will confirm or infirm the known safety profile of these new antibacterial drugs. The main AEs of the FQs class were addressed, highlighting the existing data for the recently approved ones. In addition, the general management of AEs when they occur and the rational use and caution of modern FQs were outlined.

Antimicrobial Resistance Gene Prevalence in a Population of Patients with Advanced Dementia Is Related to Specific Pathobionts

Long-term care facilities are significant reservoirs of antimicrobial-resistant organisms, and patients with advanced dementia are particularly vulnerable to multidrug-resistant organism (MDRO) acquisition and antimicrobial overuse. In this study, we longitudinally examined a group of patients with advanced dementia using metagenomic sequencing. We found significant inter- and intra-subject heterogeneity in microbiota composition, suggesting temporal instability. We also observed a link between the antimicrobial resistance gene density in a sample and the relative abundances of several pathobionts, particularly Escherichia coli, Proteus mirabilis, and Enterococcus faecalis, and used this relationship to predict resistance gene density in samples from additional subjects. Furthermore, we used metagenomic assembly to demonstrate that these pathobionts had higher resistance gene content than many gut commensals. Given the frequency and abundances at which these pathobionts were found in this population and the underlying vulnerability to MDRO of patients with advanced dementia, attention to microbial blooms of these species may be warranted.

Susceptibilities of clinical Clostridium difficile isolates to antimicrobials: a systematic review and meta-analysis of studies since 1970

OBJECTIVES

Although exposure to antibiotics can cause Clostridium difficile infection, certain antibiotics are used to treat C. difficile. Measurements of antimicrobial C. difficile activity could help to identify antibiotic risk and emergent resistance. Here, we describe publication patterns relating to C. difficile susceptibilities and estimate minimum inhibitory concentrations (MIC) for antibiotic classes in the published literature between January 1970 and June 2014.

METHODS

We queried PUBMED and EMBASE for studies reporting antibiotic C. difficile MIC in English or French. We used mixed-effects models to obtain pooled estimates of antibiotic class median MIC (MIC₅₀), 90th percentile of MIC (MIC₉₀), and MIC₉₀:MIC₅₀ ratio.

RESULTS

Our search identified 182 articles that met our inclusion criteria, of which 27 were retained for meta-analysis. Aminoglycosides (MIC₅₀ 120 mg/L, 95% CI 62-250), 3rd (MIC₅₀ 75 mg/L, 95% CI 39-130) and 2nd generation cephalosporins (MIC₅₀ 64 mg/L, 95% CI 27-140) had the least C. difficile activity. Rifamycins (MIC₅₀ 0.034 mg/L, 95% CI 0.012-0.099) and tetracyclines (MIC₅₀ 0.29 mg/L, 95% CI 0.054-1.7) had the highest level of activity. The activity of 3rd generation cephalosporins was more than three times lower than that of 1st generation agents (MIC₅₀ 19 mg/L, 95% CI 7.0-54). Time-trends in MIC₅₀ were increasing for carbapenems (70% increase per 10 years) while decreasing for tetracyclines (51% decrease per 10 years).

CONCLUSIONS

We found a 3500-fold variation in antibiotic C. difficile MIC₅₀, with aminoglycosides as the least active agents and rifamycins as the most active. Further research is needed to determine how in vitro measures can help assess patient C. difficile risk and guide antimicrobial stewardship.

Emergence and spread of moxifloxacin-resistant Clostridium difficile ribotype 231 in Sweden between 2006 and 2015

An aggregation of moxifloxacin-resistant Clostridium difficile ribotype 231 (RT231) isolates was first identified in the county of Stockholm in 2008, and by the end of 2015 isolates of RT231 had spread to 13 of 21 Swedish counties. We investigated the epidemiology of C. difficile RT231 in Sweden between 2006 and 2015 using whole genome sequencing (WGS) and evaluated whether its emergence could be associated with extended moxifloxacin use. We performed WGS and phylogenetic analysis of 51 C. difficile RT231 strains isolated in Sweden over a 10-year period. We also calculated the county-specific prescription rates for moxifloxacin between 2005 and 2015. Using WGS and detailed single nucleotide polymorphism analysis, we demonstrated three divergent sublineages of moxifloxacin-resistant C. difficile RT231 in Sweden from 2008 to 2015. A set of closely related RT231 was identified in hospitals located in the counties of Stockholm and Uppsala in 2008. Another set of RT231 isolates was found in four different counties in the Uppsala-Örebro Health Care Region. A gradual drop in moxifloxacin use in the county of Stockholm coincided with a reduction of RT231 in the area. However, RT231 continued to be frequent in surrounding counties including Uppsala, a county that also had the highest moxifloxacin prescription rates. We demonstrated frequent transmission of C. difficile RT231 within and between counties, indicating the importance of careful monitoring of hospitalized individuals infected with moxifloxacin-resistant C. difficile as well as the need for a strict moxifloxacin prescription policy.

Development of hemiacetal esterified levofloxacin to prevent chelation with metal-containing drugs

OBJECTIVES

To avoid the chelate formation between levofloxacin (LVFX) and aluminium hydroxide in gastrointestinal tract, an ethoxycarbonyl 1-ethyl hemiacetal ester of levofloxacin (LVFX-EHE) was synthesised as a prodrug.

METHODS

The effects of aluminium hydroxide on the bioavailability of LVFX following oral administration of LVFX-EHE were investigated in rats. Furthermore, the effects of aluminium hydroxide on small intestinal absorption of LVFX and LVFX-EHE when subjected to a hydrolysis experiment using in situ everted gut sac were investigated, and the minimal inhibitory concentrations (MICs) of LVFX and LVFX-EHE for various intestinal bacteria were measured.

KEY FINDINGS

When LVFX-EHE was co-administered with and without aluminium hydroxide, the AUC_{0-4 h} values of LVFX hydrolysed from LVFX-EHE were similar to that of LVFX alone. In everted gut sac experiments, LVFX-EHE was efficiently absorbed even in the presence of aluminium ions after 1 h of incubation, whereas the absorption of LVFX decreased significantly in the presence of aluminium ions. MIC values of LVFX-EHE were far higher than LVFX.

CONCLUSIONS

This study suggests the benefit of ethoxycarbonyl 1-ethyl hemiacetal esterification of the carboxyl group of new quinolone as a prodrug which is able to avoid chelate formation.

Isolation of C. difficile Carriers Alone and as Part of a Bundle Approach for the Prevention of Clostridium difficile Infection (CDI): A Mathematical Model Based on Clinical Study Data

Clostridium difficile infection is the most common hospital-acquired infection. Besides infected patients, carriers have emerged as a key player in C. difficile epidemiology. In this study, we evaluated the impact of identifying and isolating carriers upon hospital admission on the incidence of CDI incidence and hospital-acquired C. difficile colonization, as a single policy and as part of bundle approaches. We simulated C. difficile transmission using a stochastic mathematical approach, considering the contribution of carriers based on published literature. In the baseline scenario, CDI incidence was 6.18/1,000 admissions (95% CI, 5.72–6.65), simulating reported estimates from U.S. hospital discharges. The acquisition rate of C. difficile carriage was 9.72/1,000 admissions (95% CI, 9.15–10.31). Screening and isolation of colonized patients on admission to the hospital decreased CDI incidence to 4.99/1,000 admissions (95% CI, 4.59–5.42; relative reduction (RR) = 19.1%) and led to 36.2% reduction in the rate of hospital-acquired colonization. Simulating an antimicrobial stewardship program reduced CDI rate to 2.35/1,000 admissions (95% CI, 2.07–2.65). In sensitivity analysis, CDI incidence was less than 2.32/1,000 admissions (RR = 62.4%) in 95% of 1,000 simulations. The combined bundle, focusing on reducing C. difficile transmission from colonized patients and the individual risk of these patients to develop CDI, decreased significantly the incidence of both CDI and hospital-acquired colonization. Implementation of this bundle to current practice is expected to have an important impact in containing CDI.

Dual-coated lactic acid bacteria: an emerging innovative technology in the field of probiotics

Probiotics are living micro-organisms that do not naturally have shelf life, and normally are weakly protected against the digestive action of the GI tract. A new dual coating technology has been developed in an effort to maximize survival, that is, to be able to reach the intestine alive and in sufficient numbers to confer the beneficial health effects on the host. Dual-coating of lactic acid bacteria (LAB) is the result of fourth-generation coating technology for the protection of these bacteria at least 100-fold or greater than the uncoated LAB. This innovative technique involves a first pH-dependent protein layer that protects bacteria from gastric acid and bile salt, and a second polysaccharide matrix that protects bacteria from external factors, such as humidity, temperature and pressure, as well as the digestive action during the passage through the GI tract. Dual-coated probiotic formulation is applicable to different therapeutic areas, including irritable bowel syndrome, atopic dermatitis, acute diarrhea, chronic constipation, Helicobacter pylori eradication, and prevention of antibiotic-associated diarrhea. An updated review of the efficacy of doubly coated probiotic strains for improving bacterial survival in the intestinal tract and its consequent clinical benefits in humans is here presented.

Delafloxacin, a non-zwitterionic fluoroquinolone in Phase III of clinical development: evaluation of its pharmacology, pharmacokinetics, pharmacodynamics and clinical efficacy

Delafloxacin is a fluoroquinolone lacking a basic substituent in position 7. It shows MICs remarkably low against Gram-positive organisms and anaerobes and similar to those of ciprofloxacin against Gram-negative bacteria. It remains active against most fluoroquinolone-resistant strains, except enterococci. Its potency is further increased in acidic environments (found in many infection sites). Delafloxacin is active on staphylococci growing intracellularly or in biofilms. It is currently evaluated as an intravenous and intravenous/oral stepdown therapy in Phase III trials for the treatment of complicated skin/skin structure infections. It was also granted as Qualified Infectious Disease Product for the treatment of acute bacterial skin and skin structure infections and community-acquired bacterial pneumonia, due to its high activity on pneumococci and atypical pathogens.

Accuracy of loop-mediated isothermal amplification for the diagnosis of Clostridium difficile infection: a systematic review

Loop-mediated isothermal DNA amplification (LAMP) is currently used as standalone diagnostic test for C. difficile infection (CDI). We assessed the diagnostic accuracy of LAMP for the diagnosis of CDI. We searched 5 databases to identify studies that compared LAMP with culture cytotoxicity neutralization assay or anaerobic toxigenic culture (TC) of C. difficile. We used the random-effects model to calculate pooled sensitivities, specificities, diagnostic odds ratios, and their 95% confidence intervals (CIs). The search of the databases yielded 16 studies (6979 samples) that met inclusion criteria. When TC was used as the gold standard (6572 samples), bivariate analysis yielded a mean sensitivity of 0.95 (95% CI, 0.93-0.97; I(2)=67.4) and a mean specificity of 0.99 (95% CI, 0.96-1.00; I(2)=97.0). LAMP is a useful diagnostic tool with high sensitivity and specificity for detecting CDI. The results should, however, be interpreted only in the presence of clinical suspicion and symptoms of CDI.

The effect of portable pulsed xenon ultraviolet light after terminal cleaning on hospital-associated Clostridium difficile infection in a community hospital

There is evidence that contamination of patient rooms from previous occupants is associated with hospital-associated Clostridium difficile infection (HA-CDI). During January 2011, the use of 2 portable pulsed xenon ultraviolet light devices (PPX-UV) to disinfect patient rooms was added to routine hospital discharge cleaning in a community hospital. In 2010, the HA-CDI rate was 9.46 per 10,000 patient-days; in 2011, the HA-CDI rates was 4.45 per 10,000 patient-days (53% reduction, P = .01). The number of deaths and colectomies attributable to hospital-associated C difficile infection also declined dramatically.

Clostridium difficile infection in children: a comprehensive review

OBJECTIVE

To provide a comprehensive review of the literature relating to Clostridium difficile (C. difficile) infection (CDI) in the pediatric population.

METHODS

Two investigators conducted independent searches of PubMed, Web of Science, and Scopus until March 31st, 2013. All databases were searched using the terms 'Clostridium difficile infection', 'Clostridium difficile associated diarrhea' 'antibiotic associated diarrhea', 'C. difficile', in combination with 'pediatric' and 'paediatric'. Articles which discussed pediatric CDI were reviewed and relevant cross references also read and evaluated for inclusion. Selection bias could be a possible limitation of this approach.

FINDINGS

There is strong evidence for an increased incidence of pediatric CDI. Increasingly, the infection is being acquired from the community, often without a preceding history of antibiotic use. The severity of the disease has remained unchanged. Several medical conditions may be associated with the development of pediatric CDI. Infection prevention and control with antimicrobial stewardship are of paramount importance. It is important to consider the age of the child while testing for CDI. Traditional therapy with metronidazole or vancomycin remains the mainstay of treatment. Newer antibiotics such as fidaxomicin appear promising especially for the treatment of recurrent infection. Conservative surgical options may be a life-saving measure in severe or fulminant cases.

CONCLUSIONS

Pediatric providers should be cognizant of the increased incidence of CDI in children. Early and judicious testing coupled with the timely institution of therapy will help to secure better outcomes for this disease.

Comparative transcription analysis and toxin production of two fluoroquinolone-resistant mutants of Clostridium perfringens

Background

Fluoroquinolone use has been listed as a risk factor for the emergence of virulent clinical strains of some bacteria. The aim of our study was to evaluate the effect of fluoroquinolone (gatifloxacin) resistance selection on differential gene expression, including the toxin genes involved in virulence, in two fluoroquinolone-resistant strains of Clostridium perfringens by comparison with their wild-type isogenic strains.

Results

DNA microarray analyses were used to compare the gene transcription of two wild types, NCTR and ATCC 13124, with their gatifloxacin-resistant mutants, NCTR^R and 13124^R. Transcription of a variety of genes involved in bacterial metabolism was either higher or lower in the mutants than in the wild types. Some genes, including genes for toxins and regulatory genes, were upregulated in NCTR^R and downregulated in 13124^R. Transcription analysis by quantitative real-time PCR (qRT-PCR) confirmed the altered expression of many of the genes that were affected differently in the fluoroquinolone-resistant mutants and wild types. The levels of gene expression and enzyme production for the toxins phospholipase C, perfringolysin O, collagenase and clostripain had decreased in 13124^R and increased in NCTR^R in comparison with the wild types. After centrifugation, the cytotoxicity of the supernatants of NCTR^R and 13224^R cultures for mouse peritoneal macrophages confirmed the increased cytotoxicity of NCTR^R and the decreased cytotoxicity of 13124^R in comparison with the respective wild types. Fluoroquinolone resistance selection also affected cell shape and colony morphology in both strains.

Conclusion

Our results indicate that gatifloxacin resistance selection was associated with altered gene expression in two C. perfringens strains and that the effect was strain-specific. This study clearly demonstrates that bacterial exposure to fluoroquinolones may affect virulence (toxin production) in addition to drug resistance.

Effects of ciprofloxacin on the expression and production of exotoxins by Clostridium difficile

Hypervirulent BI/NAP1/027 strains of Clostridium difficile have been associated with increased mortality of C. difficile infection (CDI). The emergence of highly fluoroquinolone (FLQ)-resistant BI/NAP1/027 strains suggests that FLQ exposure may be a risk factor for CDI development. However, the mechanism for this is not clear. We compared the effects of subinhibitory concentrations of ciprofloxacin on Toxin A and B gene expression and protein production in recent (strain 039) and historical (strain 5325) BI/NAP1/027 clinical isolates with high- and low-level ciprofloxacin resistance, respectively. In the highly ciprofloxacin-resistant isolate (strain 039), ciprofloxacin significantly and dose-dependently increased Toxin A gene expression and shifted its expression to earlier in its growth cycle; TcdB gene expression also increased but was less sensitive to low-dose ciprofloxacin. Maximal Toxin A/B production (4 ng ml(-1)) was increased twofold and occurred significantly earlier than in the untreated control. In strain 5325, ciprofloxacin at 0.25×MIC markedly increased both tcdA and tcdB expression but their temporal dynamics were unchanged. Maximal toxin production (250 ng ml(-1)) was reduced approximately threefold compared with that of the untreated control. These results demonstrate significant differences in ciprofloxacin-induced toxin gene expression and protein production among BI/NAP1/027 isolates, and offer a new paradigm for FLQ-associated CDI caused by recent, highly antibiotic-resistant strains.

Oral antibiotics for fever in low-risk neutropenic patients with cancer: a double-blind, randomized, multicenter trial comparing single daily moxifloxacin with twice daily ciprofloxacin plus amoxicillin/clavulanic acid combination therapy--EORTC infectious diseases group trial XV

PURPOSE

This double-blind, multicenter trial compared the efficacy and safety of a single daily oral dose of moxifloxacin with oral combination therapy in low-risk febrile neutropenic patients with cancer.

PATIENTS AND METHODS

Inclusion criteria were cancer, febrile neutropenia, low risk of complications as predicted by a Multinational Association for Supportive Care in Cancer (MASCC) score > 20, ability to swallow, and ≤ one single intravenous dose of empiric antibiotic therapy before study drug treatment initiation. Early discharge was encouraged when a set of predefined criteria was met. Patients received either moxifloxacin (400 mg once daily) monotherapy or oral ciprofloxacin (750 mg twice daily) plus amoxicillin/clavulanic acid (1,000 mg twice daily). The trial was designed to show equivalence of the two drug regimens in terms of therapy success, defined as defervescence and improvement in clinical status during study drug treatment (< 10% difference).

RESULTS

Among the 333 patients evaluated in an intention-to-treat analysis, therapy success was observed in 80% of the patients administered moxifloxacin and in 82% of the patients administered combination therapy (95% CI for the difference, -10% to 8%, consistent with equivalence). Minor differences in tolerability, safety, and reasons for failure were observed. More than 50% of the patients in the two arms were discharged on protocol therapy, with 5% readmissions among those in either arm. Survival was similar (99%) in both arms.

CONCLUSION

Monotherapy with once daily oral moxifloxacin is efficacious and safe in low-risk febrile neutropenic patients identified with the help of the MASCC scoring system, discharged early, and observed as outpatients.

The continually evolving Clostridium difficile species

Clostridium difficile is a spore-forming Gram-positive bacterium that causes chronic diarrhea and sometimes life-threatening disease mainly in elderly and hospitalized patients. The reported incidence of C. difficile infection has changed dramatically over the last decade and has been related to the emergence of distinct clonal lineages that appear more transmissible and cause more severe infection. These include PCR ribotypes 027, 017 and more recently 078. Population biology studies using multilocus sequence typing and whole-genome comparisons has helped to define the C. difficile species into four clonal complexes that include PCR ribotypes 027, 017, 078 and 023, as well as a general grouping of most other PCR ribotypes. Further analysis of strains from diverse sources and geographical origins reveal significant microdiversity of clonal complexes and confirms that C. difficile is continuing to evolve. The study of C. difficile represents a real-time global evolutionary experiment where the pathogen is responding to a range of selective pressures created by human activity and practices in healthcare settings. The advent of whole-genome sequencing coupled with phylogeny (phylogeography and phylohistory) will provide unprecedented detail on the local and global emergence and disappearance of C. difficile clones, and facilitate more rational approaches to disease control. This review will highlight the emergence of virulent C. difficile clones and our current understanding of molecular epidemiology of the species.

The role of acute care surgery in the treatment of severe, complicated Clostridium difficile-associated disease

Clostridium difficile associated disease (CDAD) is the result of colonic bacterial overgrowth with this gram positive anaerobic organism and the production of toxins that typically induce diarrhea. Most patients with CDAD respond to treatment with oral metronidazole or vancomycin, but a subset of patients will develop a severe systemic illness, multiple organ failure, and death. There are no reliable combinations of clinical or laboratory findings that will distinguish patients who will respond to medical therapy and those who will progress to a more complicated state. Early surgical consultation should be considered in patients with ileus, severe abdominal pain, significant tenderness, immunosuppression, advanced age, high white blood cell or band counts, acute renal failure, mental status changes, or cardiopulmonary compromise. The standard operation for fulminant colitis is subtotal colectomy but the high mortality of the operation, and the long-term morbidity even in survivors combine to act as deterrents to early surgical consultation and operation. Novel operative approaches that preserve the colon and minimize operative morbidity may prove to remove the barriers to earlier surgical treatment for fulminant CDAD and improve outcomes.

Association between proton pump inhibitor therapy and Clostridium difficile infection in a meta-analysis

BACKGROUND & AIMS

In the past decade, there has been a growing epidemic of Clostridium difficile infection (CDI). During this time, use of proton pump inhibitors (PPIs) has increased exponentially. We evaluated the association between PPI therapy and the risk of CDI by performing a meta-analysis.

METHODS

We searched MEDLINE and 4 other databases for subject headings and text words related to CDI and PPI in articles published from 1990 to 2010. All observational studies that investigated the risk of CDI associated with PPI therapy and used CDI as an end point were considered eligible. Two investigators screened articles independently for inclusion criteria, data extraction, and quality assessment; disagreements were resolved based on consensus with a third investigator. Data were combined by means of a random-effects model and odds ratios were calculated. Subgroup and sensitivity analyses were performed based on study design and antibiotic use.

RESULTS

Thirty studies (25 case-control and 5 cohort) reported in 29 articles met the inclusion criteria (n = 202,965). PPI therapy increased the risk for CDI (odds ratio, 2.15, 95% confidence interval, 1.81-2.55), but there was significant heterogeneity in results among studies (P < .00001). This association remained after subgroup and sensitivity analyses, although significant heterogeneity persisted among studies.

CONCLUSIONS

PPI therapy is associated with a 2-fold increase in risk for CDI. Because of the observational nature of the analyzed studies, we were not able to study the causes of this association. Further studies are needed to determine the mechanisms by which PPI therapy might increase risk for CDI.

Clinical approach to severe Clostridium difficile infection: update for the hospital practitioner

The rising incidence of Clostridium difficile (C. difficile) infection or CDI is now a problem of pandemic proportions. The NAP1 hypervirulent strain of C. difficile is responsible for a majority of recent epidemics and the widespread use of fluoroquinolone antibiotics may have facilitated the selective proliferation of this strain. The NAP1 strain also is more likely to cause severe and fulminant colitis characterized by marked leukocytosis, renal failure, hemodynamic instability, and toxic megacolon. No single test suffices to diagnose severe CDI, instead; the clinician must rely on a combination of clinical acumen, laboratory testing, and radiologic and endoscopic modalities. Although oral vancomycin and metronidazole are considered standard therapies in the medical management of CDI, recently it has been demonstrated that vancomycin is the more effective antibiotic in cases of severe disease. Moreover, early surgical consultation is necessary in patients who do not respond to medical therapy or who demonstrate rising white blood cell counts or hemodynamic instability indicative of fulminant colitis. Subtotal colectomy with end ileostomy is the procedure of choice for fulminant colitis. When applied to select patients in a judicious and timely fashion, surgery can be a life-saving intervention. In addition to these therapeutic approaches, several investigational treatments including novel antibiotics, fecal bacteriotherapy and immunotherapy have shown promise in the care of patients with severe CDI.

Repeat stool testing to diagnose Clostridium difficile infection using enzyme immunoassay does not increase diagnostic yield

BACKGROUND & AIMS

Clostridium difficile infection (CDI) is a hospital-acquired infection with increasing incidence and severity. The most frequently used test to diagnose CDI is an enzyme immunoassay (EIA) for toxins A and B in stool samples. It is common to test 2 or more stool samples, based on the assumption that this detects CDI with greater sensitivity than analysis of 1 sample. We investigated whether repeat stool testing significantly improves the diagnostic yield for CDI.

METHODS

We performed a retrospective analysis of hospitalized patients who were tested for CDI using EIA. From year 2005 to 2008, 39,402 stool samples from 17,971 patients with 29,373 diarrhea episodes were tested. Transition probabilities were calculated based on results from repeated tests.

RESULTS

A total of 2692 diarrheal episodes (9.17%) were diagnosed with CDI. Based on results of 3 consecutive tests, 2675 (99.36%) were diagnosed with CDI. The first stool sample tested produced positive results for 90.7% of cases. When samples were tested consecutively, for the second and third time, an additional 6.6% and 2% patients had positive test results, respectively. If the first test result was negative, the probability of the second test result being positive was 2.7%. If the first 2 test results were negative, the probability of the third test result being positive was 2.3%.

CONCLUSIONS

In patients who had multiple stool samples tested for CDI by EIA, almost 91% were accurately diagnosed based on the results of a single stool sample alone. Subsequent testing yielded a positive result in only 8.6% of patients. We therefore recommend that repeat testing not be done on a routine basis because it does not significantly improve diagnostic yield.

Clostridium difficile-associated diarrhea in a tertiary care medical center

This retrospective, case-control study aimed to identify variables associated with the incidence of Clostridium difficile-associated diarrhea (CDAD) in acute care facilities and to specifically identify the relationship of fluoroquinolones and acid suppressive agents in the development of CDAD. Seventy-one symptomatic patients positive for C. difficile toxin A or B hospitalized for at least 72 hours were compared with 142 control patients hospitalized for at least 72 hours who were not positive for C. difficile toxin A or B. Two controls were matched to one case patient for age within 5 years, unit of admission, and date of admission. The mean ages for cases and controls were 63.5 and 62.7 years, respectively. After adjusting for two confounding variables-hospital stay within 3 months and Charlson Comorbidity Index-conditional multiple logistic regression identified six risk factors for development of CDAD: gastrointestinal procedures within 60 days (odds ratio [OR] 9.1, P < 0.013), levofloxacin exposure (OR 8.2, P < 0.033), moxifloxacin exposure (OR 4.1, P < 0.026), imipenem exposure (OR 14.9, P < 0.014), laxative use (OR 20.2, P < 0.0001), and immunosuppressive use (OR 20.7, P < 0.034). The risk of CDAD after exposure to levofloxacin or moxifloxacin was not significantly different. Acid suppressive therapy was not a risk factor for CDAD development.

Quantitative mass spectrometry for bacterial protein toxins--a sensitive, specific, high-throughput tool for detection and diagnosis

Matrix-assisted laser-desorption time-of-flight (MALDI-TOF) mass spectrometry (MS) is a valuable high-throughput tool for peptide analysis. Liquid chromatography electrospray ionization (LC-ESI) tandem-MS provides sensitive and specific quantification of small molecules and peptides. The high analytic power of MS coupled with high-specificity substrates is ideally suited for detection and quantification of bacterial enzymatic activities. As specific examples of the MS applications in disease diagnosis and select agent detection, we describe recent advances in the analyses of two high profile protein toxin groups, the Bacillus anthracis toxins and the Clostridium botulinum neurotoxins. The two binary toxins produced by B. anthracis consist of protective antigen (PA) which combines with lethal factor (LF) and edema factor (EF), forming lethal toxin and edema toxin respectively. LF is a zinc-dependent endoprotease which hydrolyzes specific proteins involved in inflammation and immunity. EF is an adenylyl cyclase which converts ATP to cyclic-AMP. Toxin-specific enzyme activity for a strategically designed substrate, amplifies reaction products which are detected by MALDI-TOF-MS and LC-ESI-MS/MS. Pre-concentration/purification with toxin specific monoclonal antibodies provides additional specificity. These combined technologies have achieved high specificity, ultrasensitive detection and quantification of the anthrax toxins. We also describe potential applications to diseases of high public health impact, including Clostridium difficile glucosylating toxins and the Bordetella pertussis adenylyl cyclase.

Should quinolones come first in Helicobacter pylori therapy?

New generations of fluoroquinolones, like levofloxacin and moxifloxacin, exhibit a broad-spectrum activity against Gram-positive and Gram-negative bacteria, and have been successfully introduced into the treatment of Helicobacter pylori infection. Based on a large body of evidence, current guidelines recommend the use of levofloxacin- or moxifloxacin-containing proton-pump inhibitor (PPI) triple therapies in second-line or rescue treatment of H. pylori infection. The efficacy of standard PPI triple therapies has substantially declined during the last decade, mainly due to increasing resistance against the key antibiotics clarithromycin and metronidazole. Therefore, alternative strategies for first-line therapy of H. pylori infection have been evaluated in a considerable number of clinical trials including sequential regimens, nonbismuth quadruple regimens, and quinolone-containing PPI triple therapy regimens. The aim of this paper is to summarize the current body of evidence of levofloxacin- and moxifloxacin-containing regimens in first-line treatment of H. pylori infection, and to discuss the risks and benefits of these strategies in the light of increasing resistance of H. pylori to quinolones.

Potential value of repeat stool testing for Clostridium difficile stool toxin using enzyme immunoassay?

OBJECTIVE

The aim of this brief review is to summarize the literature as it relates to the potential value of repeat stool testing for Clostridium difficile (C. difficile) toxin using an enzyme immunoassay (EIA) for toxin A&B and also propose a potential newer algorithm for diagnosing C. difficile.

RESEARCH DESIGN AND METHODS

Two investigators conducted independent literature searches using PubMed, Web of Science, and Scopus until May 1st, 2010. All databases were searched using the terms Clostridium difficile, CDAD, antibiotic associated diarrhea, C. difficile in combination with enzyme immunoassay, enzyme linked immunosorbent assay, Clostridium difficile toxin A, Clostridium difficile toxin B, Clostridium difficile toxin and repeat stool testing. Articles which discussed EIA in C. difficile infection (CDI) patients were reviewed and relevant cross references also read and evaluated for inclusion. Selection bias could be a possible limitation of the approach used in selecting or finding articles for this article.

FINDINGS

The evidence for repeat stool testing for C. difficile toxin detection using toxin EIA is becoming weaker. Most recent published practice guidelines recommend a two- or three-step testing algorithm for the detection of C. difficile.

CONCLUSIONS

EIA for C. difficile stool toxin has a limited sensitivity, but, it does not warrant repeat stool testing. The data for this are suggestive but not conclusive. More studies and better tests are needed to have clear guidelines which can specify the number of tests needed in a diagnostic workup of suspected C. difficile infection. A two-step or three-step method in the diagnosis of C. difficile-associated diarrhea offered a marked increase in sensitivity compared to that of toxin A&B EIA alone.

Shifting trends in pathogen dynamics on a changing planet

In this perspective we offer views on how microbial activities may change in response to the impact of human activities and an increasing human population. New knowledge is forthcoming in microbiology and immunology on the biology of emerging pathogens. With the exposure of human populations to changing environments, through climate change and human encroachment into previously unpopulated areas, there is likely to be increased incidences of diseases caused by existing, emerging and previously unrecognised pathogens.

Intake of Lactobacillus plantarum reduces certain gastrointestinal symptoms during treatment with antibiotics

GOALS

To examine if intake of Lactobacillus plantarum can prevent gastrointestinal side effects in antibiotic-treated patients.

BACKGROUND

Diarrhea is a common side effect of treatment with antibiotics. Some studies indicate that the risk of antibiotic-associated diarrhea can be reduced by administration of certain probiotic microorganisms.

STUDY

Patients treated for infections at a university hospital infectious diseases clinic were randomized to daily intake of either a fruit drink with L. plantarum 299v (10(10) colony forming units/d) or a placebo drink, until a week after termination of antibiotic treatment. Subjects recorded the number and consistency of stools as well as gastrointestinal symptoms until up to 3 weeks after last intake of test drink. Fecal samples were collected before the first intake of test drink and after termination of antibiotic therapy and analyzed for Clostridium difficile toxin.

RESULTS

Clinical characteristics on admission were similar in the 2 groups. The overall risk of developing loose or watery stools was significantly lower among those receiving L. plantarum [odds ratio (OR), 0.69; 95% confidence interval (CI), 0.52-0.92; P=0.012], as was development of nausea (OR, 0.51; 95% CI, 0.30-0.85; P=0.0097). Diarrhea defined as > or =3 loose stools/24 h for > or =2 consecutive days was unaffected by the treatment (OR, 1.4; 95% CI, 0.33-6.0; P=0.86). No significant differences regarding carriage of toxin producing C. difficile were observed between the groups.

CONCLUSIONS

Our results indicate that intake of L. plantarum could have a preventive effect on milder gastrointestinal symptoms during treatment with antibiotics.

Effects of subinhibitory concentrations of antibiotics on colonization factor expression by moxifloxacin-susceptible and moxifloxacin-resistant Clostridium difficile strains

Recent outbreaks of Clostridium difficile infection have been related to the emergence of the NAP1/027 epidemic strain. This strain demonstrates increased virulence and resistance to the C-8-methoxyfluoroquinolones gatifloxacin and moxifloxacin. These antibiotics have been implicated as major C. difficile infection-inducing agents. We investigated by real-time reverse transcription-PCR the impact of subinhibitory concentrations of ampicillin, clindamycin, ofloxacin, and moxifloxacin on the expression of genes encoding three colonization factors, the protease Cwp84, the high-molecular-weight S-layer protein, and the fibronectin-binding protein Fbp68. We have previously shown in six non-NAP1/027 moxifloxacin-susceptible strains that the presence of ampicillin or clindamycin induced an upregulation of these genes, whereas the presence of fluoroquinolones did not. The objective of this study was to analyze the expression of these genes under the same conditions in four NAP1/027 strains, one moxifloxacin susceptible and three moxifloxacin resistant. Two in vitro-selected moxifloxacin-resistant mutants were also analyzed. Moxifloxacin resistance was associated with the Thr82-->Ile substitution in GyrA in all but one of the moxifloxacin-resistant strains. The expression of cwp84 and slpA was strongly increased after culture with ampicillin or clindamycin in NAP1/027 strains. Interestingly, after culture with fluoroquinolones, the expression of cwp84 and slpA was only increased in four moxifloxacin-resistant strains, including the NAP1/027 strains and one of the in vitro-selected mutants. The overexpression of cwp84 was correlated with increased production of the protease Cwp84. The historical NAP1/027 moxifloxacin-susceptible strain and its mutant appear to be differently regulated by fluoroquinolones. Overall, fluoroquinolones appear to favor the expression of some colonization factor-encoding genes in resistant C. difficile strains. The fluoroquinolone resistance of the NAP1/027 epidemic strains could be considered an ecological advantage. This could also increase their colonization fitness and promote the infection.

Evidence for moxifloxacin in community-acquired pneumonia: the impact of pharmaco-economic considerations on guidelines

OBJECTIVE

In an era of limited resources, policy makers and health care payers are concerned about the costs of treatment in addition to its effectiveness. However, guidelines do not tend to consider the cost-effectiveness of treatment options. This paper aims to conduct an international literature review with a view to assessing the impact of pharmaco-economic considerations of CAP treatment with moxifloxacin on recent guidelines.

METHODS

The pharmaco-economic state of the art of treating CAP with moxifloxacin is assessed and compared with guidelines issued by the European Respiratory Society and by the Infectious Diseases Society of America/American Thoracic Society. Also, evidence on moxifloxacin consumption and antimicrobial resistance, and the impact of resistance on the cost-effectiveness of moxifloxacin is reviewed. Studies were identified by searching PubMed, Centre for Reviews and Dissemination databases, Cochrane Database of Systematic Reviews, and EconLit up to January 2009.

RESULTS

The existing pharmaco-economic evidence indicates that moxifloxacin is a cost-effective treatment for CAP. However, data limitations and uncertainty surrounding the evolution of resistance emphasize the need for caution. As recommended by guidelines, the choice of antimicrobial should consider the local frequency of causative pathogens, the local pattern of antimicrobial resistance, and risk factors for resistant bacteria. The pharmaco-economic evidence corroborates the importance of these factors as they have an impact on the cost-effectiveness of treating CAP patients with moxifloxacin.

CONCLUSIONS

CAP guidelines need to take into account pharmaco-economic considerations by balancing the effectiveness of antimicrobial regimens against their costs. The pharmaco-economic value of moxifloxacin is influenced by the causative pathogens involved and resistance patterns. Therefore, it may be advisable to identify patient subgroups in which treatment with moxifloxacin is cost-effective and should be recommended by guidelines.

Distinctive profiles of infection and pathology in hamsters infected with Clostridium difficile strains 630 and B1

Currently, the Golden Syrian hamster is widely considered an important model of Clostridium difficile disease, as oral infection of this animal pretreated with antibiotics reproduces many of the symptoms observed in humans. Two C. difficile strains, B1 and 630, showed significant differences in the progression and severity of disease in this model. B1-infected hamsters exhibited more severe pathology and a shorter time to death than hamsters infected with 630. Histological changes in the gut did not correlate with absolute numbers of C. difficile bacteria, but there were clear differences in the distribution of bacteria within gut tissues. Light, scanning, and transmission electron microscopy revealed high numbers of B1 bacteria at the mucosal surface of the tissue, whereas 630 bacteria were more frequently associated with the crypt regions. Both B1 and 630 bacteria were frequently observed within polymorphonuclear leukocytes, although, interestingly, a space frequently separated B1 bacteria from the phagosome wall, a phenomenon not observed with 630. However, pilus-like structures were detected on 630 located in the crypts of the gut tissue. Furthermore, B1 bacteria, but not 630 bacteria, were found within nonphagocytic cells, including enterocytes and muscle cells.

Does PPI therapy predispose to Clostridium difficile infection?

Clostridium difficile infection (CDI) has emerged as a problem of epidemic proportions. Previous exposure to broad-spectrum antibiotics remains the most important predisposing factor for the disease. However, PPIs are increasingly being overprescribed and recent research has, therefore, focused on the association between PPI therapy and CDI. While the data remain observational, increasing evidence exists for at least a modest association between PPI use and CDI.

Two time-series analyses of the impact of antibiotic consumption and alcohol-based hand disinfection on the incidences of nosocomial methicillin-resistant Staphylococcus aureus infection and Clostridium difficile infection

OBJECTIVE

To determine the impact of antibiotic consumption and alcohol-based hand disinfection on the incidences of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection and Clostridium difficile infection (CDI).

METHODS

Two multivariate time-series analyses were performed that used as dependent variables the monthly incidences of nosocomial MRSA infection and CDI at the Freiburg University Medical Center during the period January 2003 through October 2007. The volume of alcohol-based hand rub solution used per month was quantified in liters per 1,000 patient-days. Antibiotic consumption was calculated in terms of the number of defined daily doses per 1,000 patient-days per month.

RESULTS

The use of alcohol-based hand rub was found to have a significant impact on the incidence of nosocomial MRSA infection (P< .001). The multivariate analysis (R2=0.66) showed that a higher volume of use of alcohol-based hand rub was associated with a lower incidence of nosocomial MRSA infection. Conversely, a higher level of consumption of selected antimicrobial agents was associated with a higher incidence of nosocomial MRSA infection. This analysis showed this relationship was the same for the use of second-generation cephalosporins (P= .023), third-generation cephalosporins (P= .05), fluoroquinolones (P= .01), and lincosamides (P= .05). The multivariate analysis (R2=0.55) showed that a higher level of consumption of third-generation cephalosporins (P= .008), fluoroquinolones (P= .084), and/or macrolides (P= .007) was associated with a higher incidence of CDI. A correlation with use of alcohol-based hand rub was not detected.

CONCLUSION

In 2 multivariate time-series analyses, we were able to show the impact of hand hygiene and antibiotic use on the incidence of nosocomial MRSA infection, but we found no association between hand hygiene and incidence of CDI.

A Review of Levofloxacin for the Treatment of Bacterial Infections

Completing its initial phases of drug development in the mid 1990s as the one of the first fluoroquinolones that could be used with confidence to treat respiratory tract infections, levofloxacin went on to become one of the most widely prescribed antibiotics in the world. Available in both oral (po) and intravenous (IV) formulations and with characteristics of over 90% bioavailability, distribution into both extracellular and intracellular pulmonary compartments, highly predictable pharmacokinetics with over 90% of the drug being excreted unchanged in urine, and reliable activity against a broad spectrum of clinically important pathogens, levofloxacin has been used successfully to treat patients with a variety of serious infectious diseases as well as common infections most often treated outside of the hospital setting. Results of clinical trials involving patients with respiratory tract, urinary tract, and skin infections have consistently shown rates of clinical success and bacteriological eradication that were comparable to other widely used broad-spectrum agents. Regimens of levofloxacin, initially involving total daily doses of 250 mg to 500 mg, but more recently regimens involving 750 mg doses, have been shown to be safe and effective. Nearly a decade and a half of clinical experience has defined a safety and tolerability profile that permits data-driven assessment of the risks and benefits of using levofloxacin. As resistance to currently available fluoroquinolones has emerged, the clinical value of levofloxacin deserves continued evaluation. However, consistently high rates of susceptibility of clinically important bacteria, especially among those bacteria that commonly cause respiratory tract infections, such as Streptococcus pneumoniae and Haemophilus influenzae, suggest that this agent will continue to be a widely used well past the 20-year anniversary of its introduction into the antibacterial armamentarium.

[Quinolones]

Quinolones act by inhibiting enzymes (topoisomerases) that are essential for DNA synthesis, and probably by fragmentation of chromosomal DNA. The bactericidal activity of these drugs depends on their concentration. Their spectrum has been broadened, particularly since the introduction of a fluorine atom at position 6 (fluorquinolones). Quinolones are used in a large variety of in-hospital and community infections, as the treatment of choice or as alternative therapy. Depending on the specific compound, they are used in urinary tract infections, sexually transmitted diseases, chronic osteomyelitis, respiratory tract infections, and severe systemic infections, among others. The emergence and spread of resistance to quinolones has limited their use in some conditions and may affect their application in the future. Strategies currently exist to minimize the spread of resistance. Quinolones are well tolerated and safe. The most common adverse effects involve the gastrointestinal tract and central nervous system.

Antibiotic-associated diarrhea: epidemiology, trends and treatment

A common complication of antibiotic use is the development of gastrointestinal disease. This complication ranges from mild diarrhea to pseudomembranous colitis. Outbreaks of antibiotic-associated diarrhea (AAD) may also occur in healthcare settings, usually caused by Clostridium difficile. AAD typically occurs in 5-35% of patients taking antibiotics and varies depending upon the specific type of antibiotic, the health of the host and exposure to pathogens. The pathogenesis of AAD may be mediated through the disruption of the normal microbiota resulting in pathogen overgrowth or metabolic imbalances. The key to addressing AAD is prompt diagnosis followed by effective treatment and institution of control measures. Areas of active research include the search for other etiologies and more effective treatments.

Hospital infection society prevalence survey of Healthcare Associated Infection 2006: comparison of results between Northern Ireland and the Republic of Ireland

As part of the Third Healthcare Associated Infection (HCAI) Prevalence Survey of the United Kingdom and Ireland, HCAI point prevalence surveys were carried out in Northern Ireland (NI) and the Republic of Ireland (RoI). Here we explore the potential benefits of comparing results from two countries with different healthcare systems, which employed similar methodologies and identical HCAI definitions. Forty-four acute adult hospitals in the RoI and 15 in NI participated with a total of 11 185 patients surveyed (NI 3644 patients and RoI 7541). The overall HCAI prevalence was 5.4 and 4.9 in NI and the RoI, respectively. There was no significant difference in prevalence rates of HCAI, device-related HCAI or HCAI associated with bloodstream infection but there was a difference in meticillin-resistant Staphylococcus aureus-related HCAI (P = 0.02) between the two countries. There were significantly more urinary tract infections and Clostridium difficile infections recorded in NI (P = 0.002 and P < 0.001). HCAIs were more prevalent in patients aged >65 years and in the intensive care unit in both countries. HCAIs were also more prevalent if patients were mechanically ventilated, had had recent non-implant surgery (RoI) or had more recorded HCAI risk factors. This is the first time that HCAI prevalence rates have been directly compared between NI and the RoI. By closely examining similarities and differences between HCAI prevalence rates in both countries it is hoped that this will influence healthcare planning and at the same time reassure the public that HCAI is important and that measures are being taken to combat it.