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

STUDY OBJECTIVE

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

DESIGN

Retrospective cohort study.

SETTING

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

PATIENTS

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

INTERVENTION

N/A.

MEASUREMENTS

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

MAIN RESULTS

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

CONCLUSIONS

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

Comparison of Risk Stratification Approaches to Identify Patients with Clostridioides difficile Infection at Risk for Multidrug-Resistant Organism Gut Microbiota Colonization

INTRODUCTION

Multidrug-resistant organisms (MDRO) commonly colonize the gut microbiota of patients with Clostridioides difficile infection (CDI). This increases the likelihood of systemic infections with these MDROs. To help guide MDRO screening and/or empiric antibiotic therapy, we derived and compared predictive indices for MDRO gut colonization in patients with CDI.

METHODS

This was a multicenter, retrospective cohort study of adult patients with CDI from July 2017 to April 2018. Stool samples were screened for MDRO via growth and speciation on selective antibiotic media and confirmed using resistance gene polymerase chain reaction. A regression-based risk score for MDRO colonization was constructed. Predictive performance via area under the receiver operating characteristic curve (aROC) of this index was compared with two other simplified risk stratification approaches: (1) prior healthcare exposure and/or high-CDI risk antibiotics; (2) number of prior high-CDI risk antibiotics.

RESULTS

50 (20.8%) of 240 included patients had MDRO colonization; 35 (14.6%) VRE, 18 (7.5%) MRSA, 2 (0.8%) CRE. Prior fluoroquinolone (aOR 2.404, 95% CI 1.095-5.279) and prior vancomycin (1.996, 95% CI 1.014-3.932) were independently associated with MDRO colonization while prior clindamycin (aOR 3.257, 95% CI 0.842-12.597) and healthcare exposure (aOR 2.138, 95% CI 0.964-4.740) were retained as explanatory variables. The regression-based risk score significantly predicted MDRO colonization (aROC 0.679, 95% CI 0.595-0.763), but was not significantly more predictive than prior healthcare exposure + prior antibiotics (aROC 0.646, 95% CI 0.565-0.727) or number of prior antibiotic exposures (aROC 0.642, 95% CI 0.554-0.730); P > 0.05 for both comparisons.

CONCLUSION

A simplified approach using prior healthcare exposure and receipt of prior antibiotics known to increase CDI risk identified patients at risk for MDRO gut microbiome colonization as effectively as individual patient/antibiotic risk modeling.

Ceftolozane/tazobactam heteroresistance in cystic fibrosis-related Pseudomonas aeruginosa infections

Objectives

Cystic fibrosis (CF) patients are often colonized with Pseudomonas aeruginosa. During treatment, P. aeruginosa can develop subpopulations exhibiting variable in vitro antimicrobial (ABX) susceptibility patterns. Heteroresistance (HR) may underlie reported discrepancies between in vitro susceptibility results and clinical responses to various ABXs. Here, we sought to examine the presence and nature of P. aeruginosa polyclonal HR (PHR) and monoclonal HR (MHR) to ceftolozane/tazobactam in isolates originating from CF pulmonary exacerbations.

Methods

This was a single-centre, non-controlled study. Two hundred and forty-six P. aeruginosa isolates from 26 adult CF patients were included. PHR was defined as the presence of different ceftolozane/tazobactam minimum inhibitory concentration (MIC) values among P. aeruginosa isolates originating from a single patient specimen. Population analysis profiles (PAPs) were performed to assess the presence of MHR, defined as ≥4-fold change in the ceftolozane/tazobactam MIC from a single P. aeruginosa colony.

Results

Sixteen of 26 patient specimens (62%) contained PHR P. aeruginosa populations. Of these 16 patients, 6 (23%) had specimens in which PHR P. aeruginosa isolates exhibited ceftolozane/tazobactam MICs with categorical differences (i.e. susceptible versus resistant) compared to results reported as part of routine care. One isolate, PSA 1311, demonstrated MHR. Canonical ceftolozane/tazobactam resistance genes were not found in the MHR isolates (MHR PSA 1311 or PHR PSA 6130).

Conclusions

Ceftolozane/tazobactam PHR exists among P. aeruginosa isolates in this work, and approximately a quarter of these populations contained isolates with ceftolozane/tazobactam susceptibiilty interpretations different from what was reported clinically, supporting concerns surrounding the utility of traditional susceptibility testing methodology in the setting of CF specimens. Genome sequencing of isolates with acquired MHR to ceftolozane/tazobactam revealed variants of unknown significance. Future work will be centred on determining the significance of these mutations to better understand these data in clinical context.

Assessment of Kidney Injury as a Severity Criteria for Clostridioides Difficile Infection

BACKGROUND

The Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA) revised their Clostridioides difficile infection (CDI) severity classification criteria in 2017 to include an absolute serum creatinine (SCr) value above a threshold (≥1.5 mg/dL) rather than a relative increase from baseline (≥1.5 times the premorbid level). To date, how to best define kidney injury as a CDI disease severity marker has not been validated to assess severe outcomes associated with CDI.

METHODS

This multicenter cohort study included adult hospitalized patients with CDI. Patients were assessed for the presence of acute kidney injury (AKI), chronic kidney disease (CKD), and CDI severity using the 2010 and 2017 IDSA/SHEA CDI guidelines. Primary outcome was all-cause inpatient mortality.

RESULTS

The final study cohort consisted of 770 CDI episodes from 705 unique patients aged 65 ± 17 years (female, 54%; CKD, 36.5%; AKI, 29.6%). Eighty-two episodes (10.6%) showed discordant severity classification results due to the inclusion of more patients with preexisting CKD in the severe disease category using an absolute SCr threshold criterion. The absolute SCr criterion better correlated with all-cause mortality (odds ratio [OR], 4.04; 95% confidence interval [CI], 1.76-9.28; P = .001) than the relative increase in SCr (OR, 1.34; 95% CI, 0.62-2.89; P = .46). This corresponded to an increased likelihood of the 2017 CDI severity classification criteria to predict mortality (OR, 5.33; 95% CI, 1.81-15.72; P = .002) compared with the 2010 criteria (OR, 2.71; 95% CI, 1.16-6.32; P = .02).

CONCLUSIONS

Our findings support the 2017 IDSA/SHEA CDI severity classification criteria of a single pretreatment SCr in future CDI guideline updates.