Prevalence of Comorbid Factors in Patients With Recurrent Clostridioides difficile Infection in ECOSPOR III, a Randomized Trial of an Oral Microbiota-Based Therapeutic

BACKGROUND

Although comorbidities are risk factors for recurrent Clostridioides difficile infection (rCDI), many clinical trials exclude patients with medical conditions such as malignancy or immunosuppression. In a phase 3, double-blind, placebo-controlled, randomized trial (ECOSPOR III), fecal microbiota spores, live (VOWST, Seres Therapeutics; hereafter "VOS," formerly SER-109), an oral microbiota therapeutic, significantly reduced the risk of rCDI at week 8. We evaluated the efficacy of VOS compared with placebo in patients with comorbidities and other risk factors for rCDI.

METHODS

Adults with rCDI were randomized to receive VOS or placebo (4 capsules daily for 3 days) following standard-of-care antibiotics. In this post hoc analysis, the rate of rCDI through week 8 was assessed in VOS-treated participants compared with placebo for subgroups including (i) Charlson comorbidity index (CCI) score category (0, 1-2, 3-4, ≥5); (ii) baseline creatinine clearance (<30, 30-50, >50 to 80, or >80 mL/minute); (iii) number of CDI episodes, inclusive of the qualifying episode (3 and ≥4); (iv) exposure to non-CDI-targeted antibiotics after dosing; and (v) acid-suppressing medication use at baseline.

RESULTS

Of 281 participants screened, 182 were randomized (59.9% female; mean age, 65.5 years). Comorbidities were common with a mean overall baseline age-adjusted CCI score of 4.1 (4.1 in the VOS arm and 4.2 in the placebo arm). Across all subgroups analyzed, VOS-treated participants had a lower relative risk of recurrence compared with placebo.

CONCLUSIONS

In this post hoc analysis, VOS reduced the risk of rCDI compared with placebo, regardless of baseline characteristics, concomitant medications, or comorbidities.

Safety and Tolerability of SER-109 as an Investigational Microbiome Therapeutic in Adults With Recurrent Clostridioides difficile Infection: A Phase 3, Open-Label, Single-Arm Trial

IMPORTANCE

A safe and effective treatment for recurrent Clostridioides difficile infection (CDI) is urgently needed. Antibiotics kill toxin-producing bacteria but do not repair the disrupted microbiome, which promotes spore germination and infection recurrence.

OBJECTIVES

To evaluate the safety and rate of CDI recurrence after administration of investigational microbiome therapeutic SER-109 through 24 weeks.

DESIGN, SETTING, AND PARTICIPANTS

This phase 3, single-arm, open-label trial (ECOSPOR IV) was conducted at 72 US and Canadian outpatient sites from October 2017 to April 2022. Adults aged 18 years or older with recurrent CDI were enrolled in 2 cohorts: (1) rollover patients from the ECOSPOR III trial who had CDI recurrence diagnosed by toxin enzyme immunoassay (EIA) and (2) patients with at least 1 CDI recurrence (diagnosed by polymerase chain reaction [PCR] or toxin EIA), inclusive of their acute infection at study entry.

INTERVENTIONS

SER-109 given orally as 4 capsules daily for 3 days following symptom resolution after antibiotic treatment for CDI.

MAIN OUTCOMES AND MEASURES

The main outcomes were safety, measured as the rate of treatment-emergent adverse events (TEAEs) in all patients receiving any amount of SER-109, and cumulative rates of recurrent CDI (toxin-positive diarrhea requiring treatment) through week 24 in the intent-to-treat population.

RESULTS

Of 351 patients screened, 263 were enrolled (180 [68.4%] female; mean [SD] age, 64.0 [15.7] years); 29 were in cohort 1 and 234 in cohort 2. Seventy-seven patients (29.3%) were enrolled with their first CDI recurrence. Overall, 141 patients (53.6%) had TEAEs, which were mostly mild to moderate and gastrointestinal. There were 8 deaths (3.0%) and 33 patients (12.5%) with serious TEAEs; none were considered treatment related by the investigators. Overall, 23 patients (8.7%; 95% CI, 5.6%-12.8%) had recurrent CDI at week 8 (4 of 29 [13.8%; 95% CI, 3.9%-31.7%] in cohort 1 and 19 of 234 [8.1%; 95% CI, 5.0%-12.4%] in cohort 2), and recurrent CDI rates remained low through 24 weeks (36 patients [13.7%; 95% CI, 9.8%-18.4%]). At week 8, recurrent CDI rates in patients with a first recurrence were similarly low (5 of 77 [6.5%; 95% CI, 2.1%-14.5%]) as in patients with 2 or more recurrences (18 of 186 [9.7%; 95% CI, 5.8%-14.9%]). Analyses by select baseline characteristics showed consistently low recurrent CDI rates in patients younger than 65 years vs 65 years or older (5 of 126 [4.0%; 95% CI, 1.3%-9.0%] vs 18 of 137 [13.1%; 95% CI, 8.0%-20.0%]) and patients enrolled based on positive PCR results (3 of 69 [4.3%; 95% CI, 0.9%-12.2%]) vs those with positive toxin EIA results (20 of 192 [10.4%; 95% CI, 6.5%-15.6%]).

CONCLUSIONS AND RELEVANCE

In this trial, oral SER-109 was well tolerated in a patient population with recurrent CDI and prevalent comorbidities. The rate of recurrent CDI was low regardless of the number of prior recurrences, demographics, or diagnostic approach, supporting the beneficial impact of SER-109 for patients with CDI.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03183141.

221. Assessment and Proposed Revision of Clinical Trial Clostridioides difficile Infection Clinical Response and Outcomes Definitions

Background

Clostridioides difficile infection (CDI) research is limited by a lack of standardized definitions for clinical response and disease outcomes, which impacts clinical drug development and results comparison between studies. We aimed to assess outcome definitions in CDI therapeutic trials to propose new versions that are clinically relevant, discrete and objective.

Methods

A multidisciplinary group of CDI experts met monthly to review response endpoints from published clinical trials of antibiotic therapy for CDI. Previously published phase III or IV trials were assessed for outcome definitions. Discussions were held to reach a consensus on new clinical trial endpoints for adults and children to improve the accuracy and clinical relevance of measures of treatment success.

Results

Significant heterogeneity was noted amongst the primary endpoints in phase III and IV CDI antibiotic treatment trials. Initial clinical cure (ICC), strictly defined as < 3 unformed bowel movements/24 hour, and sustained clinical cure (SCC) were primary outcome measures for recent clinical trials. The strict ICC definition incompletely measures treatment success as assessed in clinical practice and, since ICC is necessary to achieve SCC, may lead to type II error for SCC. A set of proposed alternative outcome definitions was developed using the terms initial response (IR) and sustained response (SR) (Figure 1). IR allows for investigator assessment of overall improvement in CDI response more analogous to clinical practice and will lead to more patients eligible to meet SR. Achievement of SR requires both IR and no need for retreatment of CDI by day 30 after antibiotic completion and is the more relevant endpoint for CDI therapeutic development. The use of a less restrictive IR definition will more accurately capture early responses to treatment and importantly increase the validity of SR. The shortening of follow-up period by 30 days is also anticipated to reduce costs and efforts associated with conducting trials.

Timeline of CDI outcome assessments for clinical trials

Conclusion

The set of definitions proposed here will more accurately capture clinical success and standardize the approach to outcome assessment in trials of CDI therapeutics.

Disclosures

Carolyn D. Alonso, MD, Cidara Therapeutics: Advisor/Consultant|Merck: Advisor/Consultant Oliver A. Cornely, Prof. Dr., Abbott: Honoraria|Abbvie: Advisor/Consultant|Actelion: Board Member|Al-Jazeera Pharmaceuticals: Honoraria|Allecra Therapeutics: Board Member|Amplyx: Advisor/Consultant|Amplyx: Grant/Research Support|Astellas: Honoraria|Basilea: Advisor/Consultant|Basilea: Grant/Research Support|Biocon: Advisor/Consultant|Biosys: Advisor/Consultant|BMBF: Grant/Research Support|Cidara: Advisor/Consultant|Cidara: Board Member|Cidara: Expert Testimony|Cidara: Grant/Research Support|CoRe Consulting: Stocks/Bonds|Da Volterra: Advisor/Consultant|DLR: Grant/Research Support|DZIF: Grant/Research Support|Entasis: Board Member|EU Directorate-General for Resarch and Innovation: Grant/Research Support|F2G: Grant/Research Support|German Patent and Trade Mark Office: German patent (DE 10 2021 113 007.7)|Gilead: Advisor/Consultant|Gilead: Grant/Research Support|Grupo Biotoscana/United Medical/Knight: Honoraria|Hikma: Honoraria|IQVIA: Board Member|Janssen: Board Member|Matinas: Advisor/Consultant|Matinas: Grant/Research Support|MedPace: Advisor/Consultant|MedPace: Grant/Research Support|MedScape: Honoraria|MedUpdate: Honoraria|Menarini: Advisor/Consultant|Merck/MSD: Grant/Research Support|Merck/MSD: Honoraria|Molecular Partners: Advisor/Consultant|MSG-ERC: Advisor/Consultant|Mundipharma: Grant/Research Support|Mylan: Honoraria|Noxxon: Advisor/Consultant|Octapharma: Advisor/Consultant|Octapharma: Grant/Research Support|Paratek: Board Member|Pardes: Advisor/Consultant|Pfizer: Grant/Research Support|Pfizer: Honoraria|Projektträger Jülich: Grant/Research Support|PSI: Advisor/Consultant|PSI: Board Member|Pulmocide: Board Member|Scynexis: Advisor/Consultant|Scynexis: Grant/Research Support|Seres: Advisor/Consultant|Shionogi: Board Member|Wiley (Blackwell): Editor-in-Chief, Mycoses Kevin W. Garey, PharmD, MS, Acurx Pharmaceuticals: Grant/Research Support|Paratek Pharmaceuticals: Grant/Research Support|Seres Therapeutics: Grant/Research Support|Summit Pharmaceuticals: Grant/Research Support Dale N. Gerding, MD, Destiny Pharma plc.: Advisor/Consultant Stuart Johnson, M.D., Ferring Pharmaceuticals: Membership on Ferring Publication Steering Committee|Ferring Pharmaceuticals: Employee|Summit Plc: Advisor/Consultant Stacy A. Kahn, MD, Lilly: Stocks/Bonds Ciaran P. Kelly, n/a, Artugen: Advisor/Consultant|Facile Therapeutics: Advisor/Consultant|Ferring Pharma: Advisor/Consultant|Finch: Advisor/Consultant|Finch: Advisor/Consultant|First Light Biosciences: Advisor/Consultant|First Light Biosciences: Ownership Interest|Milky Way Biosciences: Advisor/Consultant|Milky Way Biosciences: Grant/Research Support|Pfizer: Advisor/Consultant|Seres Therapeutics: Advisor/Consultant|Summit Therapeutics: Advisor/Consultant Larry K. Kociolek, MD, MSCI, Merck: Grant/Research Support Thomas J. Louie, MD, Artugen: Advisor/Consultant|Artugen: Grant/Research Support|Crestone: Advisor/Consultant|Crestone: Grant/Research Support|Finch Therapeutics: Advisor/Consultant|Finch Therapeutics: Grant/Research Support|Rebiotix: Advisor/Consultant|Rebiotix: Grant/Research Support|Seres Therapeutics: Advisor/Consultant|Seres Therapeutics: Grant/Research Support|summit plc: Advisor/Consultant|summit plc: Grant/Research Support|Vedanta Biosciences: Advisor/Consultant|Vedanta Biosciences: Grant/Research Support Maria Vehreschild, Prof. Dr., 3M: speaker fee|Astellas: Advisor/Consultant|Astellas: speaker fee|biologische heilmittel heel gmbh: Grant/Research Support|BioNtech: Grant/Research Support|EUMEDICA: Advisor/Consultant|Farmak International Holding: Advisor/Consultant|Ferring: Advisor/Consultant|Ferring: Speaker fee|Gilead Sciences: Advisor/Consultant|Immunic AG: Advisor/Consultant|MaaT: Advisor/Consultant|Merck: Advisor/Consultant|Merck: speaker fee|MSD: Advisor/Consultant|MSD: Grant/Research Support|MSD: speaker fees|Pfizer: speaker fee|Roche Molecular Systems: Grant/Research Support|Roche Molecular Systems: speaker fees|SocraRTec R&D GmbH: Advisor/Consultant|Takeda California: Grant/Research Support Professor Mark H. Wilcox, MD, FRCPath, GSK: Advisor/Consultant|GSK: Board Member|GSK: Grant/Research Support|Pfizer: Advisor/Consultant|Phico Therapeutics: Board Member|Seres: Advisor/Consultant|Seres: Board Member|Seres: Grant/Research Support|Summit: Advisor/Consultant|Summit: Grant/Research Support Erik R. Dubberke, MD, MSPH, Abbott: Advisor/Consultant|Ferring: Advisor/Consultant|Ferring: Grant/Research Support|Merck: Advisor/Consultant|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support|Seres: Advisor/Consultant|Summit: Advisor/Consultant|Synthetic Biologics: Grant/Research Support.

730. A Phase 3, Randomized, Double-Blind Study to Evaluate the Efficacy and Safety of Ridinilazole Compared with Vancomycin for the Treatment of Clostridioides difficile Infection

Background

Vancomycin (VAN) therapy for C. difficile infection (CDI) is effective with &gt; 80% clinical response (CR) but is associated with 20–30% recurrence rate (rCDI). Secondary bile acids (2° BAs) inhibit C. difficile germination and help prevent rCDI. VAN depletes the gut microbiome decreasing the conversion of primary bile acids to 2° BAs. Ridinilazole (RDZ) is a highly selective anti-CDI, DNA-binding antibiotic in development for the treatment of CDI and prevention of rCDI.

Methods

A global, double-blinded, randomized Phase 3 trial assessed a 10-day treatment with RDZ 200 mg BID vs VAN 125 mg QID for CDI. The primary endpoint was sustained clinical response (SCR) defined as CR and no rCDI through 30 days post-end of treatment (EOT). Other endpoints included rCDI, microbiome diversity and composition, and microbiome-derived 2° BAs concentration. rCDI was defined as a new episode of diarrhea with confirmed positive free toxin test (FTT), requiring additional CDI therapy. All participants were monitored for treatment emergent adverse events (TEAE).

Results

Of the 759 patients (pts) enrolled, 745 were included in the mITT population (RDZ n=370, VAN n=375). RDZ achieved a numerically higher SCR rate than VAN (73.0% vs 70.7%) p=0.4672. RDZ resulted in a significant reduction in rCDI rate (8.1% vs 17.3%, p=0.0002) (Fig 1). In a pre-specified subpopulation, this was most notable in pts not receiving other antibiotics (rCDI 6.7% in RDZ vs 16.5% in VAN, p=0.0005). Microbiome alpha diversity was higher for RDZ vs VAN at EOT and EOT+30d (p&lt; 0.0001 and p≤ 0.0007 respectively, Fig 2) as were relative abundance (p&lt; 0.0001 and p=0.0203 respectively), and concentrations of 2° BAs (Fig 3). Higher microbiome diversity and concentrations of 2° BAs at EOT were associated with both lower rCDI and higher SCR rates. RDZ was well tolerated (pts with ≥ 1 TEAE: RDZ 36.4% vs VAN 35.5%, treatment discontinuation due to TEAE: RDZ 0.8% vs. VAN 2.9%).

Conclusion

RDZ was effective for sustained clinical response and safe for the treatment of patients with CDI. This was most notable in pts not receiving antibiotics. Compared to VAN, RDZ patients had faster recovery of fecal 2° BA, consistent with the preservation of microbiome diversity, resulting in a significantly lower rate of rCDI.

Disclosures

Pablo C. Okhuysen, MD, AstraZeneca: Stocks/Bonds|Beam Therapeutics: Stocks/Bonds|Biontech: Stocks/Bonds|Deinove: Grant/Research Support|Ferring: Advisor/Consultant|Glaxo Smith Kleine: Stocks/Bonds|Johnson and Johnson: Stocks/Bonds|Melinta: Grant/Research Support|Merck Sharp & Dohme Corp: Grant/Research Support|Moderna: Stocks/Bonds|Napo Pharmaceuticals: Advisor/Consultant|Napo Pharmaceuticals: Grant/Research Support|Novavax: Stocks/Bonds|Pfizer: Stocks/Bonds|Summit: Advisor/Consultant|Summit: Grant/Research Support Kevin W. Garey, PharmD, MS, Acurx: Grant/Research Support|cidara: Advisor/Consultant|cidara: Grant/Research Support|Paratek: Grant/Research Support|Seres Health: Grant/Research Support|Summit: Grant/Research Support Thomas J. Louie, MD, adiso therapeutics: Advisor/Consultant|adiso therapeutics: Grant/Research Support|crestone: Advisor/Consultant|crestone: Grant/Research Support|Finch: Advisor/Consultant|Finch: Grant/Research Support|Seres Therapeutics: Advisor/Consultant|Seres Therapeutics: Grant/Research Support|Seres Therapeutics: Honoraria|summit plc: Grant/Research Support|vedanta biosciences: Advisor/Consultant|vedanta biosciences: Grant/Research Support Jianling LI, MS, Abbott: Stocks/Bonds|Abbvie: Stocks/Bonds|ALX Oncology: Stocks/Bonds|BioNTech: Stocks/Bonds|Bluebird Bio: Stocks/Bonds|Cytokinetics: Stocks/Bonds|I-Mab: Stocks/Bonds|Johnson & Johnson: Stocks/Bonds|Moderna: Stocks/Bonds|TG Therapeutics: Stocks/Bonds Esther Duperchy, PhD, Summit Plc: Employee Jose G. Montoya, MD, Summit: Honoraria|Summit: Stocks/Bonds Lori Styles, MD, Abbvie: Stocks/Bonds|Summit Therapeutics: employee|Summit Therapeutics: Stocks/Bonds Fong Clow, Sc. D, Summit Therapeutics: Employee Danelle James, MD, Summit Therapeutics: Employee.

404. Surveillance of Clostridioides difficile Burden in Hospitals Through Wastewater Analysis

Background

New tools capable of dynamic assessment of the varying burden of Clostridioides difficile infections are required to mitigate increased patient morbidity, mortality, and health costs. Wastewater (WW)-based epidemiology (WBE) is an emerging science, enabling comprehensive, inclusive, and unbiased assessment of populations, spatially and temporally. We sought to detect, quantify and track C. difficile across a range of scales using WBE.

Methods

WW collected from two hospitals; the Rockyview General Hospital (RGH; 600 beds) and Peter Lougheed Centre (PLC; 550 beds) both based in Calgary, were compared to that from a municipal WW Treatment Plant (WWTP) in Calgary, Canada. DNA was extracted from pellets collected after WW centrifugation. A multiplexed quantitative PCR assay was used to quantify the abundance of C. difficile 16S rRNA and toxin A (tcdA) genes. These were then assessed as raw values or as normalized ratios to three fecal biomarker genes: total bacterial 16S rRNA, human 18S rRNA, and Bacteroides HF183 16S rRNA. Kruskal-Wallis and Mann-Whitney tests were performed using RStudio and GraphPad Prism (version 9.3.1).

Results

Eight weekly samples collected from the RGH demonstrated significant changes in the levels of total C. difficile 16S rRNA gene and tcdA over time (P=0.0004 and P=0.0005, respectively, Kruskal-Wallis). Similar trends in total C. difficile and tcdA burden over time were observed when gene copies were normalized with the three fecal biomarker genes. Over a separate 13-week comparison, C. difficile and tcdA gene target abundance was greater in hospital WW (RGH and PLC) than in community-based samples from the WWTP (P=0.048 and P=0.012, respectively, Mann-Whitney). There was no significant difference in C. difficile and tcdA gene target abundance between RGH and PLC (P=0.896 and P=0.343, respectively, Mann-Whitney).

Clostridioides difficile genes in wastewater measured by quantitative PCR.

C. difficile 16S rRNA and tcdA gene abundance normalized as a ratio against total bacterial load (16S rRNA) varies over time and is markedly increased in hospitals relative to a municipal wastewater treatment plant in Calgary, Canada.

Conclusion

WW surveillance is a powerful tool that can monitor the burden the C. difficile across a range of scales in real-time. This tool could augment infection prevention and control and antimicrobial stewardship programs to better understand factors that contribute to colonization and infection.

Disclosures

Thomas J. Louie, MD, Artugen: Advisor/Consultant|Artugen: Grant/Research Support|Crestone: Advisor/Consultant|Crestone: Grant/Research Support|Finch Therapeutics: Advisor/Consultant|Finch Therapeutics: Grant/Research Support|Rebiotix: Advisor/Consultant|Rebiotix: Grant/Research Support|Seres Therapeutics: Advisor/Consultant|Seres Therapeutics: Grant/Research Support|summit plc: Advisor/Consultant|summit plc: Grant/Research Support|Vedanta Biosciences: Advisor/Consultant|Vedanta Biosciences: Grant/Research Support.

Extended Follow-up of Microbiome Therapeutic SER-109 Through 24 Weeks for Recurrent Clostridioides difficile Infection in a Randomized Clinical Trial

This study examines adverse events and durability of response of SER-109, an investigational microbiome therapeutic comprised of purified Firmicutes spores, compared with placebo for Clostridioides difficile infection.

Efficacy and safety of SER-109, an investigational microbiome therapeutic for recurrent clostridioides difficile infection: Data from ECOSPOR III, a phase 3 randomized trial

12113

Background: Patients with malignancies are at increased risk for recurrent Clostridioides difficile infection (rCDI) due to their immunosuppressed state and frequent exposure to antibiotics and chemotherapy. These factors disrupt the gut microbiome creating an environment conducive to C. difficile colonization. Patients with cancer have higher rates of rCDI and worse outcomes than those without malignancy. SER-109, an investigational microbiome therapeutic, was superior to placebo in reducing rCDI at 8 weeks compared with placebo (12% vs 40%, respectively) in ECOSPOR III, a Phase 3 randomized, double-blind trial of subjects with a history of rCDI [NEJM 2022; 386:220-9]. Here, we report secondary endpoints of rCDI rates at 4, 12 and 24 weeks. Methods: Adults with rCDI (≥3 episodes in 12 months) were screened at 56 US/Canadian sites. After standard-of-care antibiotics (vancomycin or fidaxomicin per investigator discretion), subjects were randomized 1:1 to SER-109 (4 capsules x 3 days) or matching placebo. The primary endpoint was rCDI (recurrent toxin + diarrhea requiring treatment) at 8 weeks; secondary endpoints included rCDI at 4, 12 and 24 weeks. Safety was evaluated through week 24. Results: 281 subjects were screened and 182 (intention-to-treat population; ITT) were randomized (59.9% female; mean age 65.5 years). The most common comorbidities were respiratory disease (36.3%) and cardiovascular disease (32.4%). A total of 28.6% and 18.1% had a history of immunocompromise and malignancy, respectively. Significantly fewer SER-109 vs. placebo treated subjects had rCDI posttreatment compared with placebo recipients at Weeks 4, 8, 12 and 24 (Table). The absolute risk reduction between placebo and SER-109 arms ranged from 22.1% to 28.3% across the 4 timepoints. The safety profile of SER-109 through week 24 was comparable to placebo. Most adverse events (AEs) were mild to moderate gastrointestinal occurrences. More placebo-treated vs SER-109-treated subjects experienced serious AEs through week 8, while comparable proportions of subjects in both arms reported serious AEs from 8 through 24 weeks. Conclusions: In this population of subjects with comorbidities, including malignancy and immunosuppression, SER-109 significantly reduced rCDI rates through week 24 with an observed safety profile comparable to placebo. Clinical trial information: NCT03183128. [Table: see text]

SER-109, an Oral Microbiome Therapy for Recurrent Clostridioides difficile Infection

BACKGROUND

Current therapies for recurrent Clostridioides difficile infection do not address the disrupted microbiome, which supports C. difficile spore germination into toxin-producing bacteria. SER-109 is an investigational microbiome therapeutic composed of purified Firmicutes spores for the treatment of recurrent C. difficile infection.

METHODS

We conducted a phase 3, double-blind, randomized, placebo-controlled trial in which patients who had had three or more episodes of C. difficile infection (inclusive of the qualifying acute episode) received SER-109 or placebo (four capsules daily for 3 days) after standard-of-care antibiotic treatment. The primary efficacy objective was to show superiority of SER-109 as compared with placebo in reducing the risk of C. difficile infection recurrence up to 8 weeks after treatment. Diagnosis by toxin testing was performed at trial entry, and randomization was stratified according to age and antibiotic agent received. Analyses of safety, microbiome engraftment, and metabolites were also performed.

RESULTS

Among the 281 patients screened, 182 were enrolled. The percentage of patients with recurrence of C. difficile infection was 12% in the SER-109 group and 40% in the placebo group (relative risk, 0.32; 95% confidence interval [CI], 0.18 to 0.58; P<0.001 for a relative risk of <1.0; P<0.001 for a relative risk of <0.833). SER-109 led to less frequent recurrence than placebo in analyses stratified according to age stratum (relative risk, 0.24 [95% CI, 0.07 to 0.78] for patients <65 years of age and 0.36 [95% CI, 0.18 to 0.72] for those ≥65 years) and antibiotic received (relative risk, 0.41 [95% CI, 0.22 to 0.79] with vancomycin and 0.09 [95% CI, 0.01 to 0.63] with fidaxomicin). Most adverse events were mild to moderate and were gastrointestinal in nature, with similar numbers in the two groups. SER-109 dose species were detected as early as week 1 and were associated with bile-acid profiles that are known to inhibit C. difficile spore germination.

CONCLUSIONS

In patients with symptom resolution of C. difficile infection after treatment with standard-of-care antibiotics, oral administration of SER-109 was superior to placebo in reducing the risk of recurrent infection. The observed safety profile of SER-109 was similar to that of placebo. (Funded by Seres Therapeutics; ECOSPOR III ClinicalTrials.gov number, NCT03183128.).

634. Investigational Microbiome Therapeutic SER-109 Reduces Recurrence of Clostridioides difficile Infection (CDI) Compared to Placebo, Regardless of Risk Factors for Recurrence

Background

Several demographic and clinical characteristics, including age, sex, medication use and presence of comorbid conditions are considered risk factors for recurrent CDI (rCDI). We examined the efficacy of an investigational purified oral microbiome therapeutic, SER-109, versus placebo in an exploratory analysis of subgroups of patients with risk factors for recurrence who enrolled in ECOSPOR III, a double-blind, placebo controlled trial.

Methods

Patients with ≥ 3 CDI episodes were treated with SER-109 or placebo (four capsules daily for three days) following standard treatment of CDI. The primary efficacy objective was to demonstrate superiority of SER-109 versus placebo in reducing rCDI up to 8 weeks after treatment. In this exploratory analysis, we analyzed the rate of CDI recurrence among SER-109 treated subjects compared to placebo in subgroups defined by rCDI baseline risk factors: proton-pump inhibitor use, number of CDI recurrences, prior FMT history, presence of comorbid conditions and exposure to non-CDI antibiotics after dosing. We also analyzed the rate of CDI recurrence among SER-109 treated subjects by age (≥ 65 and ≤ 65) and gender, which were pre-specified.

Results

Of 281 patients screened,182 were enrolled. Overall recurrence rates were lower in SER-109 treated patients compared to placebo (12.4% vs 39.8%, respectively); relative risk (RR), 0.32 [95% CI, 0.18-0.58; P&lt; 0.001 for RR&lt; 1.0:P&lt; 0.001 for RR&lt; 0.833]. Co-morbidities including diabetes, renal disease, malignancy, cardiac disease, COPD/asthma, colitis, or immunocompromised status were observed in most patients in the overall study population; 33.5%, 32.4% and 34.1% had 0, 1, or ≥ 2 comorbidities. SER-109 was consistently observed to show greater benefit than placebo in reducing CDI recurrence in all subgroups regardless of the presence or absence of the rCDI risk factor (Fig 1).

Conclusion

Regardless of risk factor status, SER-109 reduced recurrence of CDI compared to placebo. Most subjects in ECOSPOR III had co-morbidities consistent with the broad inclusion criteria in this Phase 3 trial. Despite a high proportion of patients with co-morbidities in ECOSPOR III, SER-109 significantly reduced the risk of recurrence compared to placebo.

Disclosures

Stuart H. Cohen, MD, Seres (Research Grant or Support) Thomas J. Louie, MD, Artugen (Advisor or Review Panel member)Crestone (Consultant, Grant/Research Support)Da Volterra (Advisor or Review Panel member)Finch Therapeutics (Grant/Research Support, Advisor or Review Panel member)MGB Biopharma (Grant/Research Support, Advisor or Review Panel member)Rebiotix (Consultant, Grant/Research Support)Seres Therapeutics (Consultant, Grant/Research Support)Summit PLC (Grant/Research Support)Vedanta (Grant/Research Support, Advisor or Review Panel member) Matthew Sims, MD, PhD, Astra Zeneca (Independent Contractor)Diasorin Molecular (Independent Contractor)Epigenomics Inc (Independent Contractor)Finch (Independent Contractor)Genentech (Independent Contractor)Janssen Pharmaceuticals NV (Independent Contractor)Kinevant Sciences gmBH (Independent Contractor)Leonard-Meron Biosciences (Independent Contractor)Merck and Co (Independent Contractor)OpGen (Independent Contractor)Prenosis (Independent Contractor)Regeneron Pharmaceuticals Inc (Independent Contractor)Seres Therapeutics Inc (Independent Contractor)Shire (Independent Contractor)Summit Therapeutics (Independent Contractor) Elaine E. Wang, MD, Seres Therapeutics (Employee) Elaine E. Wang, MD, Seres Therapeutics (Employee, Shareholder) Barbara McGovern, MD, Seres Therapeutics (Employee, Shareholder) Kelly Brady, MS, Seres Therapeutics (Employee, Shareholder) Lisa von Moltke, MD, Seres Therapeutics (Employee, Shareholder)

LB15. SER-109, an Investigational Microbiome Therapeutic, Reduces Abundance of Antimicrobial Resistance Genes in Patients with Recurrent Clostridioides difficile Infection (rCDI) after Standard-of-Care Antibiotics

Background

The gastrointestinal microbiota is the first line of defense against colonization with antimicrobial resistant (AR) bacteria, particularly in vulnerable hosts with frequent antibiotic exposure. In a double-blind Phase 3 trial of rCDI patients, SER-109, an orally formulated consortia of purified Firmicutes spores, was superior to placebo in reducing CDI recurrence at week 8 post clinical resolution on standard-of-care (SoC) antibiotics. Overall recurrence rates were lower in SER-109 vs placebo (12.4% vs 39.8%, respectively) relative risk, 0.32 [95% CI, 0.18–0.58; p&lt; 0.001 for RR&lt; 1.0; p&lt; 0.001 for RR&lt; 0.833]. This is a post-hoc analysis examining the impact of SER-109 on antimicrobial resistance genes (ARGs) abundance in the intestinal microbiota compared to placebo.

Methods

Subjects with rCDI received SoC antibiotics, then were randomized 1:1 to SER-109 or placebo at baseline. Of 182 subjects, 140 who had paired stool samples at baseline and 1-week post-treatment were included in this analysis. ARG abundances and taxonomic profiles were generated from whole metagenomic shotgun sequencing. t-tests were used to compare changes in ARG abundance from baseline; mixed linear models were used to associate ARG and taxon abundances across time points.

Results

ARG abundance was reduced overall by week 1, with a significantly greater decrease in SER-109 subjects vs. placebo at week 1 (Fig. 1). Proteobacteria relative abundance were positively correlated with ARG abundance across all samples (Fig. 2), with the Enterobacteriaceae family associated with the abundance of 95 ARGs (all p &lt; 0.05). Enterococcaceae relative abundance was associated with glycopeptide AR abundance (p &lt; 0.001). At week 1, Proteobacteria relative abundance was significantly decreased from baseline in SER-109 subjects vs. placebo (p &lt; 0.001). Enterobacteriaceae and Enterococcaceae relative abundances were also decreased from baseline in SER-109 subjects vs. placebo (p &lt; 0.001 and p = 0.007, respectively).

Figure 1. Significant reduction in ARG abundance at week 1 from baseline in SER-109 treatment compared to placebo.

Conclusion

SER-109 was associated with significantly greater reduction of ARGs and AR bacteria abundances compared to placebo at 1 week post treatment. These findings support a potential role of microbiome therapeutics in rapid decolonization of AR bacteria with implications for infection prevention.

Disclosures

Timothy J. Straub, MS, Seres Therapeutics (Employee) Liyang Diao, PhD, Seres Therapeutics (Employee) Christopher Ford, PhD, Seres Therapeutics (Employee, Shareholder) Matthew Sims, MD, PhD, Astra Zeneca (Independent Contractor)Diasorin Molecular (Independent Contractor)Epigenomics Inc (Independent Contractor)Finch (Independent Contractor)Genentech (Independent Contractor)Janssen Pharmaceuticals NV (Independent Contractor)Kinevant Sciences gmBH (Independent Contractor)Leonard-Meron Biosciences (Independent Contractor)Merck and Co (Independent Contractor)OpGen (Independent Contractor)Prenosis (Independent Contractor)Regeneron Pharmaceuticals Inc (Independent Contractor)Seres Therapeutics Inc (Independent Contractor)Shire (Independent Contractor)Summit Therapeutics (Independent Contractor) Thomas J. Louie, MD, Artugen (Advisor or Review Panel member)Crestone (Consultant, Grant/Research Support)Da Volterra (Advisor or Review Panel member)Finch Therapeutics (Grant/Research Support, Advisor or Review Panel member)MGB Biopharma (Grant/Research Support, Advisor or Review Panel member)Rebiotix (Consultant, Grant/Research Support)Seres Therapeutics (Consultant, Grant/Research Support)Summit PLC (Grant/Research Support)Vedanta (Grant/Research Support, Advisor or Review Panel member) Colleen S. Kraft, MD, MSc, Rebiotix (Individual(s) Involved: Self): Advisor or Review Panel member Stuart H. Cohen, MD, Seres (Research Grant or Support) Stuart H. Cohen, MD, Nothing to disclose Mary-Jane Lombardo, PhD, Seres Therapeutics (Employee, Shareholder) Barbara McGovern, MD, Seres Therapeutics (Employee, Shareholder) Lisa von Moltke, MD, Seres Therapeutics (Employee, Shareholder) Matt Henn, PhD, Seres Therapeutics (Employee, Shareholder)

639. Time to Recurrence of Clostridioides difficile Infection (rCDI) is Rapid Following Completion of Standard of Care Antibiotics: Results from ECOSPOR-III, a Phase 3 Double-Blind, Placebo-Controlled Randomized Trial of SER-109, an Investigational Microbiome Therapeutic

Background

The natural history of CDI recurrence after antibiotics may be helpful to understand the window of opportunity for microbiome repair. ECOSPOR III evaluated the efficacy of SER-109, an investigational microbiome therapeutic, compared to placebo with rates of rCDI as the primary endpoint. SER-109 was superior to placebo in reducing the rate of rCDI following standard-of-care antibiotics at 8 weeks (12.4% vs 39.8%, respectively; P &lt; 0.001). Herein, we describe results from the secondary endpoint, time to recurrence, in this well-characterized study population.

Methods

A total of 182 C. difficile toxin+ adults with ≥ 3 CDI episodes and symptom resolution on CDI antibiotics were randomly assigned to SER-109 (4 capsules orally x 3 days) or placebo. Recurrence for this analysis was defined as ≥ 3 unformed stools/day for ≥ 48 hours, ± C. difficile stool toxin test, and an investigator decision to treat. Time to CDI recurrence was analyzed using observed data and Kaplan-Meier methods. Data were not imputed for subjects lost to follow-up or discontinued from study. Subjects who did not have a CDI recurrence were censored on the date of study completion, study discontinuation or death.

Results

Through 24 weeks, 11/89 (12.4%) SER-109 and 36/93 (38.7%) placebo subjects had rCDI (P &lt; 0.001). Of all recurrence events in the study population, 16/47 (34.0%) were observed within 1 week; 30/47 (63.8%) within 2 weeks; and 34/47 (72.3%) within 4 weeks after randomization, highlighting the rapid onset of recurrence. On the other hand, 12/47 (25.5%) recurrences occurred between 4 and 12 weeks, highlighting late onset of recurrence in a subset of patients (Table). Significantly lower rates of recurrence in patients on SER-109 compared to placebo was maintained throughout the 24-week follow-up (Figure).

Time of rCDI

Conclusion

SER-109, an investigational oral microbiome therapeutic, maintained significant efficacy in reducing rCDI vs placebo through 24 weeks. About two-thirds of all recurrences occurred within 14 days of antibiotic completion highlighting the need for rapid repair of the disrupted microbiome. However, the significant number of late recurrences in the placebo arm also highlights that rCDI trials limited to 4 weeks of follow-up after treatment completion may underestimate recurrences.

Disclosures

Thomas J. Louie, MD, Artugen (Advisor or Review Panel member)Crestone (Consultant, Grant/Research Support)Da Volterra (Advisor or Review Panel member)Finch Therapeutics (Grant/Research Support, Advisor or Review Panel member)MGB Biopharma (Grant/Research Support, Advisor or Review Panel member)Rebiotix (Consultant, Grant/Research Support)Seres Therapeutics (Consultant, Grant/Research Support)Summit PLC (Grant/Research Support)Vedanta (Grant/Research Support, Advisor or Review Panel member) Matthew Sims, MD, PhD, Astra Zeneca (Independent Contractor)Diasorin Molecular (Independent Contractor)Epigenomics Inc (Independent Contractor)Finch (Independent Contractor)Genentech (Independent Contractor)Janssen Pharmaceuticals NV (Independent Contractor)Kinevant Sciences gmBH (Independent Contractor)Leonard-Meron Biosciences (Independent Contractor)Merck and Co (Independent Contractor)OpGen (Independent Contractor)Prenosis (Independent Contractor)Regeneron Pharmaceuticals Inc (Independent Contractor)Seres Therapeutics Inc (Independent Contractor)Shire (Independent Contractor)Summit Therapeutics (Independent Contractor) Richard Nathan, DO, none (Other Financial or Material Support, I am PI on several clinical trials. If you need that information, I would be happy to supply it.) Princy N. Kumar, MD, AMGEN (Other Financial or Material Support, Honoraria)Eli Lilly (Grant/Research Support)Gilead (Grant/Research Support, Shareholder, Other Financial or Material Support, Honoraria)GSK (Grant/Research Support, Shareholder, Other Financial or Material Support, Honoraria)Merck & Co., Inc. (Grant/Research Support, Shareholder, Other Financial or Material Support, Honoraria) Elaine E. Wang, MD, Seres Therapeutics (Employee) Elaine E. Wang, MD, Seres Therapeutics (Employee, Shareholder) Robert Stevens, PharmD, Seres Therapeutics (Employee, Shareholder) Kelly Brady, MS, Seres Therapeutics (Employee, Shareholder) Barbara McGovern, MD, Seres Therapeutics (Employee, Shareholder) Lisa von Moltke, MD, Seres Therapeutics (Employee, Shareholder)

LB-5. DAV132 Protects Intestinal Microbiota of Patients Treated with Quinolones, a European Phase II Randomized Controlled Trial (SHIELD)

Background

Antibiotics elicit intestinal dysbiosis with short and long-term deleterious effects. A colon-targeted adsorbent, DAV132, prevents dysbiosis in healthy humans and may protect antibiotic-treated patients.

Methods

Hospitalized patients receiving oral/iv fluoroquinolones (FQ) for the treatment of or prophylaxis of febrile neutropenia were randomized to receive DAV132 (7.5g tid orally), or not, during FQ receipt and followed up 51d. Plasma FQ levels were assessed at D4 (LC-MS/MS). Feces were collected during and up to 30d after FQ receipt for assessment of free fecal FQ levels (LC-MS/MS), gut microbiome α/β diversity (16S rRNA), resistance to colonization by C. difficile (Cd; ex-vivo proliferation). Relatedness of adverse events (AEs) to drugs was adjudicated by blinded independent experts.

Results

243 patients from 23 sites, median age 71y, ≥1 chronic comorbidity 95%, received levofloxacin (43%), ciprofloxacin (40%) or moxifloxacin (18%) for (79% iv). During receipt, fecal FQ levels were lowered by >97% with DAV132 vs. No DAV132 (p< 0.0001), whilst plasma levels did not change significantly. Microbiome diversity was significantly protected with DAV132 using all metrics, e.g. the change from D1 of Shannon index at End-of-FQ (difference of means at End-of-FQ 0.42, 95% CI: 0.085; 0.752). The proportions of patients with DAV132- and/or FQ-related AEs (primary endpoint) did not differ significantly (14.8 vs. 10.8%, difference of proportions: 3.9%; 95% CI: -4.7; 12.6). No Cd infection occurred. Resistance to colonization by Cd was reduced in stools of patients receiving FQ only, but was maintained in those of patients who also received DAV132 (p=0.035). The acquisition of fecal carriage of vancomycin-resistant enterococci (VRE) was reduced with DAV132 (p=0.019).

Figure 1: a. Free fluoroquinolones fecal concentration (mean ± SEM, µg/g) over time per FQ treatment group; b. Change of Shannon Index from baseline (mean ± SEM) over time

Conclusion

DAV132 was well tolerated in elderly hospitalized patients with comorbidities. It neither altered antibiotic plasma levels nor elicited changes in concomitant drugs regimens. Intestinal microbiota diversity was protected and resistance to colonization by Cd was preserved. DAV132 is a promising, novel product to prevent antibiotic-induced intestinal dysbiosis.

Disclosures

Annie Ducher, MD, Da Volterra (Employee, Shareholder) Maria J.G.T. Vehreschild, n/a, 3M (Grant/Research Support)Astellas Pharma (Grant/Research Support)Astellas Pharma (Consultant)Astellas Pharma (Speaker's Bureau)Basilea (Speaker's Bureau)Berlin Chemie (Consultant)Da Volterra (Grant/Research Support)Da Volterra (Grant/Research Support)Gilead (Grant/Research Support)Gilead (Speaker's Bureau)Merck/MSD (Speaker's Bureau)Merck/MSD (Grant/Research Support)MSD/Merck (Consultant)Organobalance (Grant/Research Support)Organobalance (Speaker's Bureau)Pfizer (Speaker's Bureau)Seres Therapeutics (Grant/Research Support) Thomas J. Louie, MD, Da Volterra (Consultant) Oliver A. Cornely, MD, Actelion (Consultant, Grant/Research Support, Speaker's Bureau)Al Jazeera Pharmaceuticals (Consultant)Allecra Therapeutics (Consultant, Grant/Research Support, Speaker's Bureau)Amplyx (Consultant, Grant/Research Support, Speaker's Bureau)Astellas (Consultant, Grant/Research Support, Speaker's Bureau)Basilea (Consultant, Grant/Research Support, Speaker's Bureau)Biosys UK Limited (Consultant, Grant/Research Support, Speaker's Bureau)Cidara (Consultant, Grant/Research Support, Speaker's Bureau)Da Volterra (Consultant, Grant/Research Support, Speaker's Bureau)Entasis (Consultant, Grant/Research Support, Speaker's Bureau)European Commission (Grant/Research Support)F2G (Consultant, Grant/Research Support, Speaker's Bureau)German Federal Ministry of Research andEducation (Grant/Research Support)Gilead (Consultant, Grant/Research Support, Speaker's Bureau)Grupo Biotoscana (Consultant, Grant/Research Support, Speaker's Bureau)Janssen Pharmaceuticals (Consultant, Grant/Research Support, Speaker's Bureau)Matinas (Consultant, Grant/Research Support, Speaker's Bureau)MedicinesCompany (Consultant, Grant/Research Support, Speaker's Bureau)MedPace (Consultant, Grant/Research Support, Speaker's Bureau)Melinta Therapeutics (Consultant, Grant/Research Support, Speaker's Bureau)Menarini Ricerche (Consultant, Grant/Research Support, Speaker's Bureau)Merck/MSD (Consultant, Grant/Research Support, Speaker's Bureau)Mylan Pharmaceuticals (Consultant)Nabriva (Consultant)Noxxon (Consultant)Octapharma (Consultant, Grant/Research Support, Speaker's Bureau)Paratek Pharmaceuticals (Consultant, Grant/Research Support, Speaker's Bureau)Pfizer (Consultant, Grant/Research Support, Speaker's Bureau)PSI (Consultant, Grant/Research Support, Speaker's Bureau)Roche Diagnostics (Consultant)Scynexis (Consultant, Grant/Research Support, Speaker's Bureau)Shionogi (Consultant) Céline Féger, PhD, Da Volterra (Consultant) Aaron Dane, MSc, Da Volterra (Consultant)Spero theraputics (Consultant) Aaron Dane, MSc, Spero theraputics (Consultant) Marina Varastet, PhD, Da Volterra (Employee) Jean de Gunzburg, PhD, Da Volterra (Board Member, Consultant, Shareholder) Antoine Andremont, PhD, Bioaster (Consultant)Da Volterra (Board Member, Consultant, Shareholder) France Mentré, MD, Da Volterra (Consultant)

Cadazolid for the treatment of Clostridium difficile infection: results of two double-blind, placebo-controlled, non-inferiority, randomised phase 3 trials

BACKGROUND

Cadazolid is a novel quinoxolidinone antibiotic developed for treating Clostridium difficile infection. We aimed to investigate the safety and efficacy of cadazolid compared with vancomycin in patients with C difficile infection.

METHODS

IMPACT 1 and IMPACT 2 were identically designed, multicentre, double-blind, placebo-controlled, non-inferiority, randomised phase 3 trials. IMPACT 1 was done in Australia, Brazil, Canada, France, Germany, Italy, the Netherlands, Peru, Poland, Romania, Spain, and the USA, and IMPACT 2 was done in Argentina, Belgium, Brazil, Canada, Chile, Croatia, Czech Republic, Greece, Hungary, Israel, Romania, Slovakia, South Korea, the UK, and the USA. Patients (aged 18 years or older) with mild-to-moderate or severe C difficile infection (diarrhoea with positive glutamate dehydrogenase and toxin A or B enzyme immunoassays) were randomly assigned (1:1) with a randomisation list stratified by centre and C difficile infection episode type (block size of four), and allocation was masked to investigators and participants. Patients received either oral cadazolid 250 mg twice daily with vancomycin-matching placebo capsule four times daily or oral vancomycin 125 mg four times a day with cadazolid-matching placebo suspension twice daily for 10 days, with 30 days of follow-up. The primary efficacy outcome was non-inferiority (margin -10%) of cadazolid versus vancomycin for clinical cure in the modified intention-to-treat and per-protocol populations. Clinical cure was defined as resolution of diarrhoea with no additional treatment for C difficile infection. These trials are registered with ClinicalTrials.gov, numbers NCT01987895 (IMPACT 1) and NCT01983683 (IMPACT 2).

FINDINGS

Between March 28, 2014, and March 24, 2017, for IMPACT 1, and Dec 13, 2013, and May 2, 2017, for IMPACT 2, 1263 participants were randomly assigned to receive cadazolid (306 in IMPACT 1 and 298 in IMPACT 2) or vancomycin (326 in IMPACT 1 and 311 in IMPACT 2). In the modified intention-to-treat population in IMPACT 1, 253 (84%) of 302 had clinical cure in the cadazolid group versus 271 (85%) of 318 in the vancomycin group. In IMPACT 2, 235 (81%) of 290 versus 258 (86%) of 301 had clinical cure. In the per-protocol population, 247 (88%) of 282 versus 264 (92%) of 288 had clinical cure in IMPACT 1 and 214 (87%) of 247 versus 237 (92%) of 259 in IMPACT 2. Non-inferiority for clinical cure to vancomycin was shown in IMPACT 1 but not in IMPACT 2 (IMPACT 1 treatment difference: -1·4 [95% CI -7·2 to 4·3] for modified intention to treat and -4·1 [-9·2 to 1·0] for per protocol; IMPACT 2: -4·7 [-10·7 to 1·3] for modified intention to treat and -4·9 [-10·4 to 0·6] for per protocol). The safety and tolerability profiles of the two antibiotics were similar.

INTERPRETATION

Cadazolid was safe and well tolerated but did not achieve its primary endpoint of non-inferiority to vancomycin for clinical cure in one of two phase 3 C difficile infection trials. Therefore, further commercial development of cadazolid for C difficile infection is unlikely.

FUNDING

Actelion Pharmaceuticals.

Changes in Composition of the Gut Bacterial Microbiome after Fecal Microbiota Transplantation for Recurrent Clostridium difficile Infection in a Pediatric Heart Transplant Patient

The microbiome is increasingly recognized as an important influence on human health and many of the comorbidities that affect patients after solid organ transplantation (SOT) have been shown to involve changes in gut bacterial populations. Thus, microbiome changes in an individual patient may have important health implications after SOT but this area remains understudied. We describe changes in the composition of the fecal microbiome from a pediatric heart transplant recipient before and >2.5 years after he underwent repeated fecal microbiota transplantation (FMT) for recurrent Clostridium difficile infection (CDI). With both documented episodes of CDI, there was marked loss of bacterial diversity with overgrowth of Proteobacteria (>98.9% of phyla identified) associated with symptomatic colitis that was corrected after FMT. We hypothesize that a second CDI occurring after FMT was related to incomplete restoration of normal bowel flora post-FMT with relative deficiencies of the phyla Firmicutes and Bacteroidetes and the families Lachnospiraceae and Ruminococcaceae. Following the second FMT, there was a gradual shift in gut bacterial composition coincident with the recipient developing lymphonodular hyperplasia of the colon and painless hematochezia that resolved with discontinuation of mycophenolate mofetil (MMF). This case documents dynamic changes in the bacterial microbiome after FMT and suggests that MMF may influence the gut microbiome with consequences for the patient.

Clearance of Vancomycin-Resistant Enterococcus Concomitant With Administration of a Microbiota-Based Drug Targeted at Recurrent Clostridium difficile Infection

Background. Vancomycin-resistant Enterococcus (VRE) is a major healthcare-associated pathogen and a well known complication among transplant and immunocompromised patients. We report on stool VRE clearance in a post hoc analysis of the Phase 2 PUNCH CD study assessing a microbiota-based drug for recurrent Clostridium difficile infection (CDI).

Methods. A total of 34 patients enrolled in the PUNCH CD study received 1 or 2 doses of RBX2660 (microbiota suspension). Patients were requested to voluntarily submit stool samples at baseline and at 7, 30, and 60 days and 6 months after the last administration of RBX2660. Stool samples were tested for VRE using bile esculin azide agar with 6 µg/mL vancomycin and Gram staining. Vancomycin resistance was confirmed by Etest.

Results. VRE status (at least 1 test result) was available for 30 patients. All stool samples for 19 patients (63.3%, mean age 61.7 years, 68% female) tested VRE negative. Eleven patients (36.7%, mean age 75.5 years, 64% female) were VRE positive at the first test (baseline or 7-day follow-up). Of these patients, 72.7%, n = 8 converted to negative as of the last available follow-up (30 or 60 days or 6 months). Of the other 3: 1 died (follow-up data not available); 1 patient remained positive at all follow-ups; 1 patient retested positive at 6 months with negative tests during the interim.

Conclusions. Although based on a small sample size, this secondary analysis demonstrated the possibility of successfully converting a high percentage of VRE-positive patients to negative in a recurrent CDI population with RBX2660.

Differences of the Fecal Microflora With Clostridium difficile Therapies

BACKGROUND

During treatment of Clostridium difficile infection (CDI), patterns of pathogen reduction in relationship to changes in components of the normal microbiota are hypothesized to be predictive of response to treatment and subsequent sustained cure.

METHODS

At a single center, subjects enrolled into phase 2 and 3 C. difficile treatment clinical trials (2003-2008) provided fecal samples to assess killing of C. difficile and changes to components of the microbiome. Quantitative bacterial cultures, measurement of C. difficile toxin titers, quantitative polymerase chain reaction of fecal samples for Bacteroidetes, Clostridium clusters XIVa and IV, and C. difficile were performed.

RESULTS

Quantitative bacterial cultures showed a mean log10 C. difficile count (colony-forming units [CFU]) of 6.7 ± 2.0 at study entry; vancomycin treatment consistently reduced C. difficile counts to the limit of detection (2.0 log10 CFU/g), whereas metronidazole was associated with mean C. difficile counts 1.5-2 log10 higher at 10 days of treatment. In patients receiving tolevamer, C. difficile persisted in high counts during treatment; response to treatment was correlated with neutralization of toxin along with persistence of normal microbiota components. However, this was achieved in approximately half of subjects. Both vancomycin and metronidazole further suppressed microbiome components during treatment of CDI. Lactobacilli were observed to be a microbiome component that persisted during treatment of CDI.

CONCLUSIONS

Differences of pathogen clearance and microbiome perturbation during treatment of CDI appear to explain treatment outcomes. The hypothesis that probiotic microbes could help prevent onset of CDI is supported by the observation of persistence of lactobacilli during and after treatment of CDI.

Vancomycin, metronidazole, or tolevamer for Clostridium difficile infection: results from two multinational, randomized, controlled trials

BACKGROUND

Clostridium difficile infection (CDI) is a common complication of antibiotic therapy that is treated with antibiotics, contributing to ongoing disruption of the colonic microbiota and CDI recurrence. Two multinational trials were conducted to compare the efficacy of tolevamer, a nonantibiotic, toxin-binding polymer, with vancomycin and metronidazole.

METHODS

Patients with CDI were randomly assigned in a 2:1:1 ratio to oral tolevamer 9 g (loading dose) followed by 3 g every 8 hours for 14 days, vancomycin 125 mg every 6 hours for 10 days, or metronidazole 375 mg every 6 hours for 10 days. The primary endpoint was clinical success, defined as resolution of diarrhea and absence of severe abdominal discomfort for more than 2 consecutive days including day 10.

RESULTS

In a pooled analysis, 563 patients received tolevamer, 289 received metronidazole, and 266 received vancomycin. Clinical success of tolevamer was inferior to both metronidazole and vancomycin (P < .001), and metronidazole was inferior to vancomycin (P = .02; 44.2% [n = 534], 72.7% [n = 278], and 81.1% [n = 259], respectively). Clinical success in patients with severe CDI who received metronidazole was 66.3% compared with vancomycin, which was 78.5%. (P = .059). A post-hoc multivariate analysis that excluded tolevamer found 3 factors that were strongly associated with clinical success: vancomycin treatment, treatment-naive status, and mild or moderate CDI severity. Adverse events were similar among the treatment groups.

CONCLUSIONS

Tolevamer was inferior to antibiotic treatment of CDI, and metronidazole was inferior to vancomycin. Trial Registration. clinicaltrials.gov NCT00106509 and NCT00196794.

Renal impairment and clinical outcomes of Clostridium difficile infection in two randomized trials

BACKGROUND/AIMS

Patients with chronic kidney disease (CKD) have increased risk for Clostridium difficile infection (CDI) and for subsequent mortality. We determined the effect of CKD on response to treatment for CDI.

METHODS

This is a post hoc analysis of two randomized controlled phase 3 trials that enrolled patients with CDI. Patients received either fidaxomicin 200 mg b.i.d. or vancomycin 125 mg q.i.d. for 10 days. Univariate and multivariate analyses compared end points by treatment received and CKD stage.

RESULTS

At baseline, 27, 21, and 9% of the patients had stage 2 (60-89 ml/min/1.73 m(2)), stage 3 (30-59), and stage 4 or higher (<30) CKD. Cure rates were similar for normal (91%) and stage 2 CKD (92%), but declined to 80% for stage 3 and to 75% for stage 4 CKD (p < 0.001 for trend). Time to resolution of diarrhea (TTROD) increased with stage 3 and stage 4 CKD. CDI recurrence rates 4 weeks after treatment were 16, 20, 27, and 24% for normal, stage 2, stage 3, and stage 4 or higher CKD, respectively. Mortality increased with CKD stage. In multivariate analyses, stage 3 or higher CKD correlated with lower odds of cure, greater chance of recurrence, and lower odds of sustained response 28 days after treatment. Initial cure rates were similar in the vancomycin or fidaxomicin groups; however, the rate of recurrence was higher following vancomycin treatment independent of renal function. The presence of immunosuppression did not alter this effect.

CONCLUSION

Progressive CKD is associated with increased TTROD, lower cure rates, and higher recurrence rates with treatment of CDI.

Effect of age on treatment outcomes in Clostridium difficile infection

OBJECTIVES

To determine the effect of advancing age on the clinical outcomes of Clostridium difficile (CDI) treatment.

DESIGN

Regression modeling of results from two double-blind randomized multicenter studies on the treatment of primary and first recurrent cases of CDI to examine for effects of age and study drug on outcomes of cure (resolution of diarrhea), recurrence within 4 weeks of completing successful therapy, and cure without recurrence.

SETTING

Participants were randomized into studies in the United States, Canada, and Europe.

PARTICIPANTS

Nine hundred ninety-nine individuals with toxin-positive CDI were randomized to receive vancomycin (125 mg 4 times daily) or fidaxomicin (200 mg twice daily) for 10 days.

MEASUREMENTS

The effect of advancing age in those aged 18 to 40 years and in 10-year increments thereafter was examined.

RESULTS

The model predicts a 17% lower clinical cure, 17% greater recurrence, and 13% lower sustained clinical response by advancing decade than in those younger than 40 (P < .01 each). Clinical cure was similar in the fidaxomicin and vancomycin treatment groups, although fidaxomicin was associated with a more than 50% lower relative risk for recurrence than vancomycin (P < .001). Multivariate regression modeling showed that risk factors accounting for poorer outcomes with advancing age include infection with the BI strain type, inpatient status, renal insufficiency, leukocytosis, hypoalbuminemia, and concomitant medication exposure.

CONCLUSION

Measurable and progressive deterioration in CDI treatment outcomes occurred with advancing age in those aged 40 and older, highlighting the need for prevention and treatment strategies. Fidaxomicin treatment was associated with a 60% lower risk of recurrence than vancomycin after adjusting for age, concomitant antibiotics, and C. difficile strain.

Fidaxomicin preserves the intestinal microbiome during and after treatment of Clostridium difficile infection (CDI) and reduces both toxin reexpression and recurrence of CDI

The microflora-sparing properties of fidaxomicin were examined during the conduct of a randomized clinical trial comparing vancomycin 125 mg 4 times per day versus fidaxomicin 200 mg twice per day for 10 days as treatment of Clostridium difficile infection (CDI). Fecal samples were obtained from 89 patients (45 received fidaxomicin, and 44 received vancomycin) at study entry and on days 4, 10, 14, 21, 28, and 38 for quantitative cultures for C. difficile and cytotoxin B fecal filtrate concentrations. Additionally, samples from 10 patients, each receiving vancomycin or fidaxomicin, and 10 samples from healthy controls were analyzed by quantitative real-time polymerase chain reaction with multiple group-specific primers to evaluate the impact of antibiotic treatment on the microbiome. Compared with controls, patients with CDI at study entry had counts of major microbiome components that were 2-3-log(10) colony-forming units (CFU)/g lower. In patients with CDI, fidaxomicin allowed the major components to persist, whereas vancomycin was associated with a further 2-4-log(10) CFU reduction of Bacteroides/Prevotella group organisms, which persisted to day 28 of the study, and shorter term and temporary suppression of both Clostridium coccoides and Clostridium leptum group organisms. In the posttreatment period, C. difficile counts similarly persisted in both study populations, but reappearance of toxin in fecal filtrates was observed in 28% of vancomycin-treated patient samples (29 of 94), compared with 14% of fidaxomicin-treated patient samples (13 of 91; P = .03). Similarly, 23% of vancomycin-treated patients (10 of 44) and 11% of fidaxomicin-treated patients (5 of 44) had recurrence of CDI. Whereas vancomycin and fidaxomicin are equally effective in resolving CDI symptoms, preservation of the microflora by fidaxomicin is associated with a lower likelihood of CDI recurrence.

Fidaxomicin versus vancomycin for Clostridium difficile infection: meta-analysis of pivotal randomized controlled trials

Two recently completed phase 3 trials (003 and 004) showed fidaxomicin to be noninferior to vancomycin for curing Clostridium difficile infection (CDI) and superior for reducing CDI recurrences. In both studies, adults with active CDI were randomized to receive blinded fidaxomicin 200 mg twice daily or vancomycin 125 mg 4 times a day for 10 days. Post hoc exploratory intent-to-treat (ITT) time-to-event analyses were undertaken on the combined study 003 and 004 data, using fixed-effects meta-analysis and Cox regression models. ITT analysis of the combined 003/004 data for 1164 patients showed that fidaxomicin reduced persistent diarrhea, recurrence, or death by 40% (95% confidence interval [CI], 26%–51%; P < .0001) compared with vancomycin through day 40. A 37% (95% CI, 2%–60%; P = .037) reduction in persistent diarrhea or death was evident through day 12 (heterogeneity P = .50 vs 13–40 days), driven by 7 (1.2%) fidaxomicin versus 17 (2.9%) vancomycin deaths at <12 days. Low albumin level, low eosinophil count, and CDI treatment preenrollment were risk factors for persistent diarrhea or death at 12 days, and CDI in the previous 3 months was a risk factor for recurrence (all P < .01). Fidaxomicin has the potential to substantially improve outcomes from CDI.

Fidaxomicin attains high fecal concentrations with minimal plasma concentrations following oral administration in patients with Clostridium difficile infection

Fidaxomicin has recently been approved for the treatment of Clostridium difficile infection (CDI). As part of phase III studies, plasma and fecal samples were analyzed for concentrations of fidaxomicin and its metabolite, OP-1118. Plasma samples were collected before and after dose receipt on the first and last days of therapy, and fecal samples were collected on the last day of therapy. Samples were analyzed for fidaxomicin and OP-1118 (metabolite), using validated liquid chromatography/tandem mass spectrometric methods. Plasma concentrations were low for both fidaxomicin (mean [± standard deviation {SD}], 22.8 ± 26.7 ng/mL and 28.5 ± 33.4 ng/mL on the first and last days of therapy, respectively) and OP-1118 (mean [±SD], 44.5 ± 50.4 ng/mL and 85.6 ± 131 ng/mL, respectively). In contrast, fecal levels were >1000 µg/g for fidaxomicin and >800 µg/g for OP-1118. Fidaxomicin mean fecal levels were >5000 times the minimum inhibitory concentration for C. difficile of 0.25 µg/mL.

Treatment of first recurrence of Clostridium difficile infection: fidaxomicin versus vancomycin

Recurrence of Clostridium difficile infection (CDI) occurs in approximately 25% of successfully treated patients. Two phase 3 randomized, double-blind trials were conducted at 154 sites in the United States, Canada, and Europe to compare fidaxomicin vs vancomycin in treating CDI. Patients with CDI received fidaxomicin 200 mg twice daily or vancomycin 125 mg 4 times daily for 10 days. The primary end point was clinical cure of CDI at end of treatment, and a secondary end point was recurrence during the 28 days following clinical cure. In all, 1164 subjects were enrolled, of which a subgroup of 128 in the per-protocol population had another recent episode of CDI prior to the CDI diagnosis at study enrollment. In the analysis of this subgroup, initial response to therapy was similar for both drugs (>90% cure). However, recurrence within 28 days occurred in 35.5% of patients treated with vancomycin and 19.7% of patients treated with fidaxomicin (−15.8% difference; 95% confidence interval, −30.4% to −0.3%; P = .045). Early recurrence (within 14 days) was reported in 27% of patients treated with vancomycin and 8% of patients treated with fidaxomicin (P = .003). In patients with a first recurrence of CDI, fidaxomicin was similar to vancomycin in achieving a clinical response at end of therapy but superior in preventing a second recurrence within 28 days.

Clinical Trials Registration. NCT00314951 and NCT00468728.

Efficacy of fidaxomicin versus vancomycin as therapy for Clostridium difficile infection in individuals taking concomitant antibiotics for other concurrent infections

Concomitant antibiotic (CA) use compromised initial response to Clostridium difficile infection therapy and durability of that response. Fidaxomicin was significantly more effective than vancomycin in achieving clinical cure in the presence of CAs and preventing recurrence regardless of CA use.

Background. Treatment guidelines recommend stopping all implicated antibiotics at the onset of Clostridium difficile infection (CDI), but many individuals have persistent or new infections necessitating the use of concomitant antibiotics (CAs). We used data from 2 phase 3 trials to study effects of CAs on response to fidaxomicin or vancomycin.

Methods. Subjects with CDI were treated for 10 days with fidaxomicin 200 mg every 12 hours or vancomycin 125 mg every 6 hours, assessed for resolution of symptoms, and followed up for an additional 4 weeks for evidence of recurrence. Rates of cure, recurrence, and global cure (cure without recurrence) were determined for subgroups of subjects defined by CA use and treatment group.

Results. CAs were prescribed for 27.5% of subjects during study participation. The use of CAs concurrent with CDI treatment was associated with a lower cure rate (84.4% vs 92.6%; P < .001) and an extended time to resolution of diarrhea (97 vs 54 hours; P < .001). CA use during the follow-up was associated with more recurrences (24.8% vs 17.7%; not significant), and CA administration at any time was associated with a lower global cure rate (65.8% vs 74.7%; P = .005). When subjects received CAs concurrent with CDI treatment, the cure rate was 90.0% for fidaxomicin and 79.4% for vancomycin (P = .04). In subjects receiving CAs during treatment and/or follow-up, treatment with fidaxomicin compared with vancomycin was associated with 12.3% fewer recurrences (16.9% vs 29.2%; P = .048).

Conclusions. Treatment with CAs compromised initial response to CDI therapy and durability of response. Fidaxomicin was significantly more effective than vancomycin in achieving clinical cure in the presence of CA therapy and in preventing recurrence regardless of CA use.

Fidaxomicin versus vancomycin for Clostridium difficile infection

BACKGROUND

Clostridium difficile infection is a serious diarrheal illness associated with substantial morbidity and mortality. Patients generally have a response to oral vancomycin or metronidazole; however, the rate of recurrence is high. This phase 3 clinical trial compared the efficacy and safety of fidaxomicin with those of vancomycin in treating C. difficile infection.

METHODS

Adults with acute symptoms of C. difficile infection and a positive result on a stool toxin test were eligible for study entry. We randomly assigned patients to receive fidaxomicin (200 mg twice daily) or vancomycin (125 mg four times daily) orally for 10 days. The primary end point was clinical cure (resolution of symptoms and no need for further therapy for C. difficile infection as of the second day after the end of the course of therapy). The secondary end points were recurrence of C. difficile infection (diarrhea and a positive result on a stool toxin test within 4 weeks after treatment) and global cure (i.e., cure with no recurrence).

RESULTS

A total of 629 patients were enrolled, of whom 548 (87.1%) could be evaluated for the per-protocol analysis. The rates of clinical cure with fidaxomicin were noninferior to those with vancomycin in both the modified intention-to-treat analysis (88.2% with fidaxomicin and 85.8% with vancomycin) and the per-protocol analysis (92.1% and 89.8%, respectively). Significantly fewer patients in the fidaxomicin group than in the vancomycin group had a recurrence of the infection, in both the modified intention-to-treat analysis (15.4% vs. 25.3%, P=0.005) and the per-protocol analysis (13.3% vs. 24.0%, P=0.004). The lower rate of recurrence was seen in patients with non–North American Pulsed Field type 1 strains. The adverse-event profile was similar for the two therapies.

CONCLUSIONS

The rates of clinical cure after treatment with fidaxomicin were noninferior to those after treatment with vancomycin. Fidaxomicin was associated with a significantly lower rate of recurrence of C. difficile infection associated with non–North American Pulsed Field type 1 strains. (Funded by Optimer Pharmaceuticals; ClinicalTrials.gov number, NCT00314951.)

Proton pump inhibitors increase significantly the risk of Clostridium difficile infection in a low-endemicity, non-outbreak hospital setting

BACKGROUND

Proton pump inhibitors (PPI) have been linked to higher risk of Clostridium difficile infection (CDI). The relevance of this association in hospitals with low disease activity, where an outbreak strain is nondominant, has been assessed in relatively few studies.

AIM

To assess the association of PPI and CDI in a setting of low disease activity.

METHODS

A retrospective cohort study was conducted at two hospitals. Patients admitted for > or = 7 days receiving antibiotics were included. Demographics, exposure to PPI, antibiotics and other drugs in relation to diagnosis of CDI were assessed by univariate and multivariate analyses.

RESULTS

Of 14 719 patients, 149 (1%) first episode CDI were documented; PPI co-exposure increased CDI [1.44 cases/100 patients vs. 0.74 cases/100 non-exposed (OR: 1.96, 95% CI: 1.42-2.72)]. By logistic regression, PPI days (adjusted OR: 1.01 per day, 95% CI: 1.00-1.02), histamine-2 blockers, antidepressants, antibiotic days, exposure to medications, age, admission service and length of admission were significant predictors.

CONCLUSIONS

A statistically significant increase in CDI was observed in antibiotic recipients who received PPI, but the absolute risk increase is modest. In settings of with low rates of CDI, the benefit of PPI therapy outweighs the risk of developing CDI. These data support programmes to decrease inappropriate use of PPI in hospitalized patients.

Development of a Health-Related Quality of Life Questionnaire (HRQL) for patients with Extremity Soft Tissue Infections (ESTI)

Background

Past clinical trials of antimicrobial treatment in soft tissue infections have focused on non-standardized clinical and physiological outcome variables, and have not considered the subjective experience of patients. The objective of this study was to develop a health-related quality of life questionnaire (HRQL) for patients with extremity soft tissue infections (ESTI) for future use in clinical trials.

Methods

The design of this study followed published guidelines and included item generation, item reduction, and questionnaire preparation. Study subjects were consenting English-speaking adults with acute ESTI requiring prescription of at least two days of outpatient intravenous antibiotic therapy.

Results

A list of 49 items that adversely impact the quality of life of patients with ESTI was generated by literature review, informal health professional feedback, and semi-structured interviews with twenty patients. A listing of these items was then administered to 95 patients to determine their relative importance on quality of life. A questionnaire was prepared that included the twenty most important items with a 5-point Likert scale response. Questionnaire domains included physical symptoms, problems performing their activities of daily living, impairment of their emotional functioning, and difficulties in their social interactions as related to their ESTI. The final questionnaire was pre-tested on a further ten patients and was named the ESTI-Score.

Conclusion

The ESTI-Score is a novel instrument designed to quantify the impact of ESTI on quality of life. Future study is required to determine its validity and responsiveness before use as an outcome measure in clinical trials.

Molecular analysis of Clostridium difficile PCR ribotype 027 isolates from Eastern and Western Canada

The prevalence and characteristics of PCR ribotype 027 strains of Clostridium difficile have come into question following recent outbreaks in Eastern Canada and elsewhere. In order to determine the distribution of this strain in other regions in Canada, we screened a bank of 1,419 isolates recovered from three different Canadian health regions between 2000 and 2004. Among isolates from a Montreal area hospital, PCR ribotype 027 strains represented 115/153 strains (75.2%) from 2003 to 2004, but ribotype 027 strains were absent in 2000 and 2001. In Calgary, by contrast, ribotype 027 rates have remained relatively stable over 4 years of surveillance, representing 51/685 (7.4%) hospital isolates and 62/373 (16.6%) strains from the community (P < 0.001). PCR ribotype 027 accounted for 8/135 (5.9%) hospital isolates in the Fraser Health Region in 2004. repetitive extragenic palindromic PCR was used to subtype a random selection of 027 isolates from each region. All 10 of the isolates from Quebec were of a single subtype, which was also dominant among isolates from Alberta (8/10 isolates) and British Columbia (6/8 isolates). Comparative sequencing of the tcdC repressor gene confirmed the documented 18-bp deletion and identified a second, single-base-pair deletion at position 117. Both deletions were conserved across all three provinces and were identified in a United Kingdom reference strain. The presence of a frameshift in the early portion of the tcdC gene implies serious functional disruption and may contribute to the hypervirulence of the 027 phenotype. PCR ribotype 027 strains appear to be widely distributed, to predate the Montreal outbreak, and to have measurable community presence in Western Canada.

Tolevamer, a novel nonantibiotic polymer, compared with vancomycin in the treatment of mild to moderately severe Clostridium difficile-associated diarrhea

BACKGROUND

Current antibiotic therapies for Clostridium difficile-associated diarrhea have limitations, including progression to severe disease, recurrent C. difficile-associated diarrhea, and selection for nosocomial pathogens. Tolevamer, a soluble, high-molecular weight, anionic polymer that binds C. difficile toxins A and B is a unique nonantibiotic treatment option.

METHODS

In this 3-arm, multicenter, randomized, double-blind, active-controlled, parallel-design phase II study, patients with mild to moderately severe C. difficile-associated diarrhea were randomized to receive 3 g of tolevamer per day (n = 97), 6 g of tolevamer per day (n = 95), or 500 mg of vancomycin per day (n = 97). The primary efficacy parameter was time to resolution of diarrhea, defined as the first day of 2 consecutive days when the patient had hard or formed stools (any number) or < or = 2 stools of loose or watery consistency.

RESULTS

In the per-protocol study population, resolution of diarrhea was achieved in 48 (67%) of 72 patients receiving 3 g of tolevamer per day (median time to resolution of diarrhea, 4.0 days; 95% confidence interval, 2.0-6.0 days), in 58 (83%) of 70 patients receiving 6 g of tolevamer per day (median time to resolution of diarrhea, 2.5 days; 95% confidence interval, 2.0-3.0 days), and in 73 (91%) of 80 patients receiving vancomycin (median time to resolution of diarrhea, 2.0 days; 95% confidence interval, 1.0-3.0 days). Tolevamer administered at a dosage of 6 g per day was found to be noninferior to vancomycin administered at a dosage of 500 mg per day with regard to time to resolution of diarrhea (P = .02) and was associated with a trend toward a lower recurrence rate. Tolevamer was well tolerated but was associated with an increased risk of hypokalemia.

CONCLUSIONS

Tolevamer, a novel polystyrene binder of C. difficile toxins A and B, effectively treats mild to moderate C. difficile diarrhea and merits further clinical development.

Population-based epidemiological study of infections caused by carbapenem-resistant Pseudomonas aeruginosa in the Calgary Health Region: importance of metallo-beta-lactamase (MBL)-producing strains

BACKGROUND

A study was conducted in the Calgary Health Region between May 2002 and April 2004 to define the population-based epidemiological characteristics of infections caused by imipenem-resistant Pseudomonas aeruginosa and to explore the clinical outcomes due to metallo- beta -lactamase (MBL)-producing and non-MBL-producing strains.

METHODS

Detailed clinical information was obtained by chart review, and phenotypic and molecular characterizations were performed using the MBL E-test, polymerase chain reaction with sequencing, and pulsed-field gel electrophoresis.

RESULTS

A total of 228 patients with infections caused by imipenem-resistant P. aeruginosa were identified (annual incidence, 10.5 cases/100,000 population), with the highest incidence rate in those >or=75 years old. MBL-producing strains (98/228) were associated with higher rates of multidrug resistance and bacteremia. Ninety MBL-producing strains also produced VIM-2, 4 produced IMP-7, and 4 were unclassified. A cluster of VIM-2-producing strains was responsible for a nosocomial outbreak during 2003. The case-fatality rate was significantly higher for infections caused by MBL-producing strains than for those caused by non-MBL-producing strains (25% vs. 13%; relative risk, 1.98 [95% confidence interval, 1.00-3.90]; P=.05).

CONCLUSION

MBL-producing P. aeruginosa strains were associated with a higher case-fatality rate and invasive disease. Our study highlights the potential importance of molecular laboratory techniques in infection control and patient care.

Understanding influenza vaccination attitudes at a Canadian cancer center

BACKGROUND

Although influenza vaccination benefits both health care workers and their patients, participation by staff in vaccination programs is disappointingly low. Understanding health care worker perceptions and needs is essential for improving rates of vaccination.

METHODS

A self-administered questionnaire was distributed to all staff at a Canadian cancer center. Information was sought on previous frequency of participation in influenza vaccination, as well as motivations, perceptions, and preferences.

RESULTS

Three hundred sixty-three (70%) of 515 cancer center staff members responded. Twenty-two percent of staff were vaccinated 4 or 5 times in the past 5 years and were primarily motivated by the desire to protect their own health (81%). Forty-nine percent participated 1 to 3 times in the past 5 years, and this group had diverse knowledge and vaccine-access needs. Twenty-nine percent received no vaccination in the previous 5 years because they believed the vaccine lacked efficacy (45%) or was harmful to health (19%). Moving from high to low levels of participation with influenza vaccination, the following trends were observed: increasing belief that vaccines cause illnesses or weaken the immune system, increasing belief that adverse effects of vaccination are underreported, and decreasing belief that vaccination programs are beneficial.

CONCLUSIONS

Cancer center staff perceptions about influenza vaccination differ according to the past frequency of vaccine uptake. Strategies for promoting vaccination should be guided by these differences.

Understanding influenza vaccination attitudes at a Canadian cancer center

BACKGROUND

Although influenza vaccination benefits both health care workers and their patients, participation by staff in vaccination programs is disappointingly low. Understanding health care worker perceptions and needs is essential for improving rates of vaccination.

METHODS

A self-administered questionnaire was distributed to all staff at a Canadian cancer center. Information was sought on previous frequency of participation in influenza vaccination, as well as motivations, perceptions, and preferences.

RESULTS

Three hundred sixty-three (70%) of 515 cancer center staff members responded. Twenty-two percent of staff were vaccinated 4 or 5 times in the past 5 years and were primarily motivated by the desire to protect their own health (81%). Forty-nine percent participated 1 to 3 times in the past 5 years, and this group had diverse knowledge and vaccine-access needs. Twenty-nine percent received no vaccination in the previous 5 years because they believed the vaccine lacked efficacy (45%) or was harmful to health (19%). Moving from high to low levels of participation with influenza vaccination, the following trends were observed: increasing belief that vaccines cause illnesses or weaken the immune system, increasing belief that adverse effects of vaccination are underreported, and decreasing belief that vaccination programs are beneficial.

CONCLUSIONS

Cancer center staff perceptions about influenza vaccination differ according to the past frequency of vaccine uptake. Strategies for promoting vaccination should be guided by these differences.

Bloodstream infection-associated sepsis and septic shock in critically ill adults: a population-based study

BACKGROUND

Few studies have investigated the epidemiology of sepsis and septic shock in a large population and none have been from Canada. The objective of this study was to define the epidemiology of bloodstream infection (BSI)-associated sepsis and septic shock among all critically ill patients in a large, fully integrated health region in Canada.

PATIENTS AND METHODS

All critically ill adults admitted to multidisciplinary intensive care units (ICU) in the Calgary Health Region during May 1, 1999 to April 30, 2000 were included. Clinical, microbiologic and outcome information was obtained from regional databases.

RESULTS

We surveyed 1981 patients having at least one ICU admission. Systemic inflammatory response syndrome (SIRS) was diagnosed in 92%, BSI-associated sepsis (BSI with SIRS) in 6% and BSI-associated septic shock (BSI with SIRS and hypotension) in 3%; respective hospital mortality rates were 36%, 40% and 49%. The most common BSI etiologies were Staphylococcus aureus, Escherichia coli and Streptococcus species; only one isolate (1%) was highly antibiotic resistant. Independent risk factors for death among patients with SIRS included age (>or= 65), hypothermia (< 35 degrees C), and higher APACHE II and TISS scores. A surgical diagnosis was associated with decreased mortality risk. Neither a positive blood culture nor hypotension at presentation independently predicted death.

CONCLUSION

Knowledge of the epidemiology of these syndromes is important for assessing the burden of disease and providing background information for investigating new therapies.

Population-based assessment of intensive care unit-acquired bloodstream infections in adults: Incidence, risk factors, and associated mortality rate

OBJECTIVE

Nosocomial bloodstream infections have been extensively investigated, but relatively few studies have specifically evaluated the epidemiology of intensive care unit-acquired bloodstream infections. The study objective was to define the incidence, risk factors, microbiology, and clinical outcomes of intensive care unit-acquired bloodstream infections.

DESIGN

Population-based prospective cohort.

SETTING

Multidisciplinary intensive care units.

PATIENTS

All Calgary Health Region (population 930,000) adult patients admitted to multidisciplinary intensive care units (>/=48 hrs) from May 1, 1999, to April 30, 2000.

INTERVENTIONS

Blood sample analysis.

MEASUREMENTS AND RESULTS

There were 1,158 admission episodes in 1,017 patients; 37% involved females, and mean +/- sd age and Acute Physiology and Chronic Health Evaluation II scores were 59.6 +/- 18.7 yrs and 23.4 +/- 7.7, respectively. Fifty-one patients developed intensive care unit-acquired bloodstream infections (first positive blood culture >/=48 hrs after intensive care unit admission) for an incidence of 4.4% and an incidence density of 5.2 per 1000 intensive care unit days. Younger age (adjusted odds ratio, 0.98; 95% confidence interval, 0.96-1.00, p =.01), longer intensive care unit length of stay (adjusted odds ratio, 4.74; 95% CI, 3.26-6.90, p <.001), and lower hematocrit (adjusted odds ratio, 0.95; 95% confidence interval, 0.90-1.00, p =.04) were significant independent predictors of intensive care unit-acquired bloodstream infections, and these infections were associated with an increased intensive care unit length of stay of 2.86 days (95% confidence interval, 2.29-3.57, p <.001). Staphylococcus aureus (27%), coagulase-negative staphylococci (14%), and Enterococcus faecium (12%) were most commonly isolated. Four (8%) bloodstream infections involved antibiotic-resistant organisms, and ten (20%) were polymicrobial. In multivariate analysis, intensive care unit-acquired bloodstream infection was associated with an increased intensive care unit mortality rate (adjusted odds ratio, 2.03; 95% confidence interval, 1.03-4.00, p = 0.04) but not overall hospital mortality rate.

CONCLUSIONS

One patient in 20 admitted to Calgary Health Region intensive care units acquires bloodstream infection and suffers longer intensive care unit stay and increased mortality rates. In our region, multiple antibiotic-resistant organisms are uncommon causes of bloodstream infections, suggesting that it may be safe to use narrower spectrum empirical treatment regimens than current guidelines recommend.

Incidence and risk factors for acquiring nosocomial urinary tract infection in the critically ill

PURPOSE

A urinary tract infection (UTI) is the most common hospital-acquired infection. However, the epidemiology of intensive care unit (ICU)-acquired UTIs is not well defined. The objective of this study was to describe the incidence, risk factors, and clinical outcomes of ICU-acquired UTIs.

MATERIALS AND METHODS

All patients admitted to adult multidisciplinary ICUs in the Calgary Health Region (CHR, population approximately 1 million) during May 1, 1999 to April 30, 2000 were studied using a cohort design.

RESULTS

A total of 1,158 admissions to a CHR ICU were 48 hours in duration or more. A total of 111 episodes of ICU-acquired UTI (defined as >10(5) CFU/mL of 1 or 2 organisms >48 hours after ICU admission) occurred in 105 (9%) patients and 5 (0.4%) had ICU-acquired bacteremic/fungemic UTIs for incidences of 11.3 and 0.5 UTIs per 1,000 ICU days, respectively. Significant independent risk factors for developing an ICU-acquired UTI as determined by a logistic regression model were female gender (adjusted odds ratio [OR(adj)], 2.31; 95% confidence interval [CI], 1.48-3.59) and natural logarithmic transformation of ICU length of stay (OR(adj), 3.96; 95% CI, 3.02-5.17). No differences in admitting vital signs, routine blood tests, APACHE II and TISS scores, or overall hospital mortality rate were observed among patients who developed an ICU-acquired UTI as compared with those who did not. The most common UTI etiologies were Enterococcus spp. (24%), Candida albicans (21%), and Escherichia coli (15%). Only 4 (3%) of the organisms were highly antibiotic resistant.

CONCLUSIONS

Nosocomial UTIs develop commonly in the critically ill and women and those with an extended ICU stay are at increased risk. Although ICU-acquired UTIs are markers of morbidity, they do not significantly increase mortality.

Nosocomial outbreak of carbapenem-resistant Pseudomonas aeruginosa with a new bla(IMP) allele, bla(IMP-7)

Pseudomonas aeruginosa isolates from an outbreak in Canada were highly resistant to carbapenems and ceftazidime but not piperacillin. They produced a novel integron-associated metallo-beta-lactamase, designated IMP-7, with 91% identity to IMP-1. bla(IMP-7) was not detected with standard bla(IMP)-specific primers, owing to mismatches in the forward primer.

Randomized, double-blind, multicenter trial comparing clinafloxacin with imipenem as empirical monotherapy for febrile granulocytopenic patients

In a double-blind, multicenter trial, 541 febrile granulocytopenic patients were randomized to receive either intravenous (iv) clinafloxacin (200 mg every 12 h) or i.v. imipenem (500 mg every 6 h) as empirical monotherapy. More baseline pathogens were susceptible to clinafloxacin (259 [99%] of 262 organisms) than to imipenem (253 [95%] of 265; P=.03). Initial favorable clinical response rates for clinafloxacin (88 [32%] of 272 patients) and imipenem (89 [33%] of 269) were similar. After addition of other antimicrobial agents, overall response rates were 259 (95%) of 272 for clinafloxacin and 251 (93%) of 269 for imipenem. During the study, only 13 clinafloxacin (5%) and 18 imipenem (7%) recipients died. Both drugs were generally well tolerated. Drug-related skin rash occurred more often with clinafloxacin (11% vs. 6%; P=.07), whereas nausea (2% vs. 5%; P=.16), Clostridium-difficile-associated diarrhea (3% vs. 8%; P=.02), and seizures (0% vs. 2%; P=.06) occurred more often with imipenem. These results suggest that clinafloxacin and imipenem have similar efficacy as empirical monotherapy in febrile granulocytopenic patients.

Comparison of higher-dose intradermal hepatitis B vaccination to standard intramuscular vaccination of healthcare workers

OBJECTIVE

To compare the immunogenicity of hepatitis B vaccine administered via intradermal (ID) versus intramuscular (IM) route.

METHODS

Subjects chose either to specify the route of immunization or to undergo random allocation to vaccination by the ID (0.15 mL) or the IM (1.0 mL) route. Yeast-derived recombinant hepatitis B vaccine was given at 0, 30, and 180 days. Hepatitis B surface antibody (HBsAb) and hepatitis B core antibody (HBcAb) were measured by microparticle enzyme immunoassay.

RESULTS

763 subjects were enrolled. Baseline screening identified 65 subjects (8%) who were positive for HBsAb or HBcAb. Vaccination was completed by 590 (85%) of 698 enrollees (370 ID, 220 IM). Seroconversion rates (geometric mean titers [GMT]>0 IU/mL HBsAb) for those vaccinated ID were 99% and 96% for screening at 9 months and 1 year post-vaccination, respectively; subjects vaccinated intramuscularly had similar rates of 95% and 96%. Seropositivity rates (GMT > or = 10 IU/mL HBsAb) showed a similar pattern, with 95%, 92%, and 73% at 9 months and 1 and 2 years, respectively, for those vaccinated ID, and 94%, 93%, and 81% for those having IM vaccination. GMT for HBsAb was significantly higher for individuals vaccinated IM than for those vaccinated ID (P<.0001). The GMT ratio for the IM and ID routes decreased over time, being 9.3 at 9 months, 7.8 at 1 year, and 5.9 at 2 years. An unanticipated side effect of intradermal vaccination was skin discoloration at injection sites, which persisted for at least 2 years postvaccination. Two thirds (112/166) of respondents reported that they would have selected the ID route despite the discoloration.

CONCLUSIONS

Higher-dose ID vaccination (3 vs 1 microg per injection) uses one sixth of the dose required for standard IM vaccination. It is a cost-effective way to vaccinate populations against hepatitis B virus, but the long-term efficacy of the ID route must still be investigated.

Comparison of ceftiofur sodium and oxytetracycline for treatment of acute interdigital phlegmon (foot rot) in feedlot cattle

OBJECTIVE

To determine whether ceftiofur sodium would be useful for treatment of acute interdigital phlegmon (foot rot) in cattle.

DESIGN

Randomized controlled trial.

ANIMALS

308 cross-bred yearling steers with clinical signs of acute interdigital phlegmon (i.e., lameness with interdigital swelling, interdigital lesions, or both).

PROCEDURE

Steers were randomly assigned to 1 of 3 treatment groups: ceftiofur at a dosage of 0.1 mg/kg (0.045 mg/lb) of body weight, IM, every 24 hours; ceftiofur at a dosage of 1.0 mg/kg (0.45 mg/lb), IM, every 24 hours, and oxytetracycline at a dosage of 6.6 mg/kg (3 mg/lb), IM, every 24 hours. All animals were treated for 3 days; treatment was considered successful if animals were no longer lame on day 4. Biopsy specimens were collected prior to treatment from 5 animals in each group and submitted for anaerobic bacterial culture and histologic examination.

RESULTS

Success rates for the high-dosage ceftiofur (94/129; 73%) and oxytetracycline (87/128; 68%) groups were significantly higher than that for the low-dosage ceftiofur group (5/50; 10%), but there were no significant differences between the high-dosage ceftiofur and oxytetracycline groups. Anaerobic bacteria most frequently isolated from biopsy specimens were Porphyromonas levii and Provetella intermedia.

CLINICAL IMPLICATIONS

Use of ceftiofur at a dosage of 1.0 mg/kg for treatment of cattle with acute interdigital phlegmon was as effective as use of oxytetracycline at a dosage of 6.6 mg/kg. However, ceftiofur has a negligible withdrawal time and, therefore, may be a better choice for treatment of near-market weight animals.

Quinolone-based antibacterial chemoprophylaxis in neutropenic patients: effect of augmented gram-positive activity on infectious morbidity. National Cancer Institute of Canada Clinical Trials Group

OBJECTIVE

To determine whether augmented quinolone-based antibacterial prophylaxis in neutropenic patients with cancer reduces infections caused by gram-positive cocci and preserves the protective effect against aerobic gram-negative bacilli.

DESIGN

Open, randomized, controlled, multicenter clinical trial.

SETTING

Centers participating in the National Cancer Institute of Canada Clinical Trials Group.

PATIENTS

111 eligible and evaluable patients hospitalized for severe neutropenia (neutrophil count < 0.5 x 10(9)/L lasting at least 14 days) who were receiving cytotoxic therapy for acute leukemia or bone marrow autografting.

INTERVENTION

One of three oral antibacterial prophylactic regimens (norfloxacin, 400 mg every 12 hours; ofloxacin, 400 mg every 12 hours; or ofloxacin, 400 mg, plus rifampin, 300 mg every 12 hours) beginning with cytotoxic therapy.

MEASUREMENTS

Incidence and cause of suspected or proven infection.

RESULTS

Microbiologically documented overall infection rates for norfloxacin, ofloxacin, and ofloxacin plus rifampin were 47%, 24%, and 9%, respectively (P < 0.001). Corresponding rates were 24%, 13%, and 3%, respectively for staphylococcal bacteremia (P = 0.03) and, 21%, 3%, and 3%, respectively for streptococcal bacteremia (P < 0.01). The pattern of bacteremia suggested that rifampin played a role in suppressing staphylococcal infection. Both ofloxacin alone and ofloxacin plus rifampin had a clinically significant antistreptococcal effect. Aerobic gram-negative rods were cleared from rectal surveillance cultures in all patients after a median of 5.5 days and caused infection in only one patient (0.9%). The reductions in the number of microbiologically documented infections among ofloxacin recipients and ofloxacin plus rifampin recipients were offset by concomitant increases in the number of unexplained fevers (24% of norfloxacin recipients, 53% of ofloxacin recipients, and 49% of ofloxacin plus rifampin recipients; P = 0.02). No statistically significant difference was found among the treatment arms with respect to the overall incidence of febrile neutropenic episodes as defined for this trial (79% for the norfloxacin group, 82% for the ofloxacin group, and 77% for the ofloxacin plus rifampin group).

CONCLUSIONS

Quinolone-based antibacterial chemoprophylaxis protected patients from aerobic gram-negative bacillary infections. Augmentation of the gram-positive activity reduced the incidence of gram-positive infections but did not influence the overall incidence of febrile neutropenic episodes.

Should infection control practitioners do follow-up of staff exposures to patient blood and body fluids?

BACKGROUND

The purpose of this study was to determine the efficiency of a joint infection control/occupational health program for the follow-up of accidental blood or bloody body fluid exposures in health care workers.

METHODS

A comprehensive staff follow-up program for all blood exposures with known patient sources was initiated in 1989, consisting of patient follow-up by the Infection Control Department (risk assessment for hepatitis B virus [HBV] and [HIV] infection and obtaining of consent for HIV testing) and staff follow-up by the Occupational Health Department. In 1992 a mailed survey was conducted to examine exposure follow-up policies and responsibilities in large teaching hospitals across Canada.

RESULTS

A total of 924 blood exposures with known patient sources were reported between January 1989 and December 1993. HIV and HBV screening was obtained for 67.9% and 87.6% of patients assessed as at low risk and 82.3% and 92.2% of those assessed as at high risk for infection, respectively. Two previously unknown HIV-seropositive patients were identified, one of whom had been classified as at low risk (one of 530 [0.19%] patients at low risk who underwent screening). Primary reasons for screening being missed were patient discharge (46.3%) or communication problems (18.0%). The requirement for informed written consent before HIV screening accounted for the difference in completed HIV and HBV screens. Results of the hospital survey indicated that 40.8% of Canadian hospitals follow up all patients who are involved in blood exposures; however, most hospitals still rely on the physician to obtain consent (87.6%).

CONCLUSIONS

Use of ICPs to screen patients involved in staff blood exposures during regular hours may be the most efficient method of follow-up, particularly if supplemented by a backup team of health professionals on nights and weekends. Although screening all patients for HBV/HIV may detect patients with undisclosed high-risk behaviors, institutions must decide whether the practice is cost-effective in areas of low prevalence.

Impact of free verotoxin testing on epidemiology of diarrhea caused by verotoxin-producing Escherichia coli

During a 10-week period in the summer of 1990, an epidemiologic investigation of the prevalence of verotoxin (VT)-producing Escherichia coli infection was conducted in Calgary, Alberta, Canada. Consecutive stool specimens (n = 3,577) were cultured for E. coli O157:H7, and fecal filtrates were tested for free VTs (FVTs). E. coli O157:H7 was recovered from 22 specimens (0.6%), but VT was detected in 74 specimens (2.1%). Sixty-nine stool specimens positive for FVTs or E. coli O157:H7 were probed for VT genes by colony blot hybridization; 22 of 38 VT gene probe-positive isolates were non-O157:H7 E. coli organisms. Fourteen of 22 strains could not be induced to produce VT in vitro, despite the presence of FVTs in the stool sample, positivity on colony blot hybridization, positive PCR probes with the primers described by Pollard et al. (D. R. Pollard, W. M. Johnson, H. Lior, S. D. Tyler, and K. R. Rozee, J. Clin. Microbiol. 28:540-545, 1990) or Gannon et al. (V. P. Gannon, R. K. King, J. Y. Kim, and E. J. Golsteyn-Thomas, Appl. Environ. Microbiol. 58:3809-3815, 1992) (but not those described by Karch and Meyer [H. Karch and T. Meyer, J. Clin. Microbiol. 27:2751-2757, 1989]), and positive Southern blot analysis of isolates in 10 of 14 strains. The patient survey questionnaire showed that E. coli O157:H7 infection was associated with bloody diarrhea of short duration, whereas infection with other serotypes or persistence of FVT only was associated with longer-duration nonbloody diarrheal illness. We conclude that (i) detection of FVT in stools enhances the diagnosis of VT infection threefold over cultures for E. coli O157:H7, (ii) cultures for E.coli O157:H7 detect the majority of organisms of that serotype, (iii) the spectrum of disease produced by organisms of non-O157:H7 serotypes may include less severe but more protracted illness, and (iv) differences in the in vivo and in vitro expression of toxin and results of genetic probe studies highlight the need to examine control mechanisms of toxin production.

Molecular epidemiology of Xanthomonas maltophilia colonization and infection in the hospital environment

Between April 1992 and December 1993, 80 Xanthomonas maltophilia isolates were collected from 63 patients in three acute-care hospitals in Calgary, Alberta, Canada. On the basis of Centers for Disease Control and Prevention definitions, 48 patients had nosocomial and 15 had community-acquired X. maltophilia. Thirty-eight of the patients were colonized and 25 were infected. Sixty-four percent of patients who acquired X. maltophilia in the intensive care unit (ICU) became infected, whereas 32% of patients in a non-ICU setting became infected. ICU patients tended to be hospitalized for a shorter period of time than non-ICU patients before the onset of X. maltophilia infection. Regardless of being colonized or infected, all patients had debilitating conditions, with respiratory disease being the most common underlying illness (35%). Forty-two patients (88%) with hospital-acquired X. maltophilia received prior antibiotic therapy which included gentamicin, tobramycin, ceftazidime, piperacillin, and imipenem. Agar dilution MICs showed that patient isolates were resistant to these antimicrobial agents that patients had received. Pulsed-field gel electrophoresis of SpeI-digested genomic DNA revealed that six epidemiologically linked patient isolates from the ICU of one acute-care hospital had identical DNA profiles. In contrast, isolates from patients from the other two hospitals had unique genotype profiles (n = 57) regardless of the presence or absence of an epidemiologic association. In these patients there was genetic evidence against the acquisition of a resident hospital clone. These results indicate that pulsed-field gel electrophoresis can resolve genotypically distinct strains of X. maltophilia and, consequently, is a useful tool for evaluating nosocomial infections caused by X. maltophilia.

Direct detection of verotoxin-producing Escherichia coli in stool samples by PCR

A method for the rapid detection of verotoxin-producing Escherichia coli in stool samples by PCR was evaluated. Verotoxin-1 and verotoxin-2 genes in DNA extracted directly from stool samples were amplified with oligonucleotide primers. Stools spiked with control organisms, E. coli C600 (H19B) (verotoxin-1) or E. coli C600 (933W) (verotoxin-2), demonstrated that verotoxin-1-containing organisms could be detected at 10(2) CFU per 0.1 g of stool and verotoxin-2-containing organisms could be detected at 10(7) CFU per 0.1 g of stool. Testing of stool samples from patients with diarrhea showed a high concordance between PCR positivity and the presence of verotoxin-producing E. coli, determined by isolation of serotype O157:H7 on sorbitol-MacConkey medium (34 of 35 stool samples) or by colony blots with gene probes (19 of 21 stool samples). Conversely, only 1 of 20 (5.0%) stool samples that were O157:H7 culture negative and colony blot negative and that contained free verotoxin only was positive by PCR. As well, only 4 of 145 (2.8%) stool samples that were negative for serotype O157:H7 or free verotoxin were PCR positive. PCR of DNA extracted directly from stool samples provides a rapid method for the detection of stool samples containing verotoxin-producing E. coli compared with colony blot testing.

Treatment of complicated urinary tract infections with lomefloxacin compared with that with trimethoprim-sulfamethoxazole

The efficacy of lomefloxacin given at 400 mg once daily for 14 days compared with that of trimethoprim-sulfamethoxazole at 160 and 800 mg, respectively, given twice daily for 14 days in the treatment of symptomatic complicated urinary tract infections was studied in a prospective, randomized, single-blind multicenter study. A total of 133 subjects presenting with signs and symptoms of urinary tract infection and an underlying abnormality consistent with complicated urinary tract infection were enrolled in the study. Bacteriologic cure was significantly better in 68 subjects randomized to lomefloxacin than in 65 subjects randomized to trimethoprim-sulfamethoxazole at short-term follow-up (88 versus 52%; 95% confidence intervals [CIs] 77 and 94% and 39 and 65%, respectively) this difference was no longer significant at long-term follow-up (64 versus 47%; CIs, 52 and 75% and 32 and 57%, respectively). Clinical outcomes were similar for both therapeutic regimens at short- and long-term follow-ups. The organisms that infected the subjects pretherapy were more frequently resistant to trimethoprim-sulfamethoxazole, and drug therapy was discontinued more frequently in subjects treated with trimethoprim-sulfamethoxazole because of adverse antimicrobial effects. In secondary analyses, outcomes did not differ with age or underlying genitourinary abnormality.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of enzyme immunoassay for Candida cytoplasmic antigens in neutropenic cancer patients

A Candida albicans cytoplasmic antigen enzyme immunoassay (CACP antigen EIA) was developed with antibodies raised against antigens prepared from yeast cells grown under standardized growth conditions. The C. albicans components reactive in the EIA were shown to be predominantly proteins with associated carbohydrates. Denaturing gel electrophoresis revealed the presence of five major CACP proteins with molecular weights between 36,000 and 44,000. The clinical usefulness of the CACP EIA was evaluated by retrospective blinded measurement of 89 serum samples from 31 granulocytopenic patient episodes. Twice-weekly surveillance cultures, sequential serum samples (approximately once per week or with change of the clinical course), and standard diagnostic criteria of fungal infection were used to categorize patients. The sensitivity and specificity of the CACP assay on the basis of serum samples were 82 and 100%, respectively (67 and 100% on the basis of patient episodes). The positive and negative predictive values were 100 and 97% for serum (100 and 93% for patient episodes). By comparison, the CANDTEC assay had low sensitivity (33%) and poor positive predictive values (50%). The CACP EIA may be a useful test suitable for further evaluations as a method for the diagnosis of invasive Candida infection in neutropenic cancer patients.