Changes in antibiotic consumption, AMR and Clostridioides difficile infections in a large tertiary-care center following the implementation of institution-specific guidelines for antimicrobial therapy: A nine-year interrupted time series study

Development of a Weighted-Incidence Syndromic Combination Antibiogram (WISCA) to guide empiric antibiotic treatment for ventilator-associated pneumonia in a Mexican tertiary care university hospital

BACKGROUND

Ventilator-associated pneumonia (VAP) is a significant nosocomial infection in critically ill patients, leading to high morbidity, mortality, and increased healthcare costs. The diversity of local microbiology and resistance patterns complicates the empirical treatment selection. The Weighted-Incidence Syndromic Combination Antibiogram (WISCA) offers an innovative tool to optimize empirical antibiotic therapy by integrating local microbiological data and resistance profiles.

OBJECTIVE

To develop a WISCA tailored for VAP in a Mexican tertiary care university hospital, aiming to enhance empirical antibiotic coverage by addressing the unique pathogen distribution and resistance patterns within the institution.

METHODS

This retrospective study included 197 VAP episodes from 129 patients admitted to a critical care unit between June 2021 and June 2024. Clinical and microbiological data, including pathogen susceptibility profiles, were analyzed using a Bayesian hierarchical model to evaluate the coverage of multiple antibiotic regimens. We also assessed the current impact of inappropriate empiric or directed treatment on in-hospital mortality using Cox regression models to support the development of a WISCA model.

RESULTS

The median age of the patients was 44 years (IQR 35-56), with Acinetobacter baumannii (n = 71), Enterobacterales (n = 53) and Pseudomonas aeruginosa (n = 36) identified as the most frequently isolated pathogens. The developed WISCA models showed variable coverage based on antibiotic regimens and the duration of invasive mechanical ventilation (IMV). Inappropriate directed therapy during the VAP episode was associated with increased mortality, as were the diagnosis of Acute Respiratory Distress Syndrome (ARDS) and a high Sequential Organ Failure Assessment (SOFA) score (p < 0.01).

CONCLUSIONS

The tailored WISCA with Bayesian hierarchical modeling provided more adaptive, subgroup-specific estimates and managed uncertainty better compared to fixed models. The implementation of this WISCA model demonstrated potential to optimize antibiotic strategies and improve clinical outcomes in critically ill patients in our hospital.

TOPIC

Optimizing Empirical Antibiotic Therapy for Ventilator-Associated Pneumonia Using a Weighted-Incidence Syndromic Combination Antibiogram in a Mexican Tertiary Care Hospital.

A practice-based approach to teaching antimicrobial therapy using artificial intelligence and gamified learning

Objectives

Scalable teaching through apps and artificial intelligence (AI) is of rising interest in academic practice. We focused on how medical students could benefit from this trend in learning antibiotic stewardship (ABS). Our study evaluated the impact of gamified learning on factual knowledge and uncertainty in antibiotic prescription. We also assessed an opportunity for AI-empowered evaluation of freeform answers.

Methods

We offered four short courses focusing on ABS, with 46 participating medical students who self-selected themselves into the elective course. Course size was limited by the faculty. At the start of the course, students were given a questionnaire about microbiology, infectious diseases, pharmacy and qualitative questions regarding their proficiency of selecting antibiotics for therapy. Students were followed up with the same questionnaire for up to 12 months. We selected popular game mechanics with commonly known rules for teaching and an AI for evaluating freeform questions.

Results

The number of correctly answered questions improved significantly for three topics asked in the introductory examination, as did the self-assessed safety of prescribing antibiotics. The AI-based review of freeform answers was found to be capable of revealing students' learning gaps and identifying topics in which students needed further teaching.

Conclusions

We showed how an interdisciplinary short course on ABS featuring gamified learning and AI could substantially improve learning. Even though large language models are a relatively new technology that sometimes fails to produce the anticipated results, they are a possible first step in scaling a tutor-based teaching approach in ABS.

The changing epidemiology of Clostridioides difficile infection and the NAP1/027 strain in two Québec hospitals: a 17-year time-series study

Objective

To describe the epidemiology of healthcare-associated Clostridioides difficile infection (HA-CDI) in two Québec hospitals in Canada following the 2003 epidemic and to evaluate the impact of antibiotic stewardship on the incidence of HA-CDI and the NAP1/027 strain.

Design

Time-series analysis.

Setting

Two Canadian tertiary care hospitals based in Montréal, Québec.

Patients

Patients with a positive assay for toxigenic C. difficile were identified through infection control surveillance. All cases of HA-CDI, defined as symptoms occurring after 72 hours of hospital admission or within 4 weeks of hospitalization, were included.

Methods

The incidence of HA-CDI and antibiotic utilization from 2003 to 2020 were analyzed with available C. difficile isolates. The impact of antibiotic utilization on HA-CDI incidence was estimated by a dynamic regression time-series model. Antibiotic utilization and the proportion of NAP1/027 strains were compared biannually for available isolates from 2010 to 2020.

Results

The incidence of HA-CDI decreased between 2003 and 2020 at both hospitals from 26.5 cases per 10,000 patient-days in 2003 to 4.9 cases per 10,000 patient-days in 2020 respectively. Over the study period, there were an increase in the utilization of third-generation cephalosporins and a decrease in usage of fluoroquinolones and clindamycin. A decrease in fluoroquinolone utilization was associated with a significant decrease in HA-CDI incidence as well as decrease in the NAP1/027 strain by approximately 80% in both hospitals.

Conclusions

Decreased utilization of fluoroquinolones in two Québec hospitals was associated with a decrease in the incidence of HA-CDI and a genotype shift from NAP1/027 to non-NAP1/027 strains.

Comparison of Cefazolin and Ceftriaxone Enterobacterales Susceptibilities for Inpatient Treatment of Urinary Tract Infections and Risk of Hospital-onset Clostridioides difficile Infection

PURPOSE

Urinary tract infection (UTI) is the second most common indication for antibiotic therapy among inpatients in the United States. Ceftriaxone, a third-generation cephalosporin, is habitually chosen to treat inpatient UTIs due to familiarity, cost, and perceived safety. However, third-generation cephalosporins increase the risk of health care facility-onset Clostridioides difficile infection (HOCDI) more than any other antibiotic group, while no statistical risk exists for first-generation cephalosporins. Recent evidence comparing Enterobacterales susceptibility for first- and third-generation cephalosporins in urinary specimens in the United States is limited. This analysis assessed the comparative activity of cefazolin and ceftriaxone for Enterobacterales urinary isolates and incidence of HOCDI to determine the usefulness of cefazolin as an empirical agent to manage inpatient UTI and limit ceftriaxone collateral damage.

METHODS

This was a retrospective single-center observational study. Microbiologic susceptibility data were analyzed for Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis urinary specimens taken from adult inpatients admitted from January 1, 2022, to December 31, 2022. Primary outcome was incidence of E coli, K pneumoniae, and P mirabilis susceptibility to cefazolin in uncomplicated UTI (MIC <16 µg/mL). Secondary outcomes include susceptibility for complicated UTI and HOCDI risk associated with cefazolin and ceftriaxone.

FINDINGS

A total of 1150 urine samples were identified as E coli, K pneumoniae, and P mirabilis in 2022. Susceptibility to cefazolin was observed in 1064 (92.5%) of 1150 isolates using the MIC breakpoint for uncomplicated UTI and to ceftriaxone in 1115 (97.0%) of 1150 isolates (P < 0.001). From 2016 to 2022, either cefazolin or ceftriaxone was administered in 26,462 inpatient admissions, with HOCDI diagnoses occurring in 89 admissions. HOCDI developed in 78 admissions (0.40%) with ceftriaxone exposure, and 11 cases (0.15%) developed in cefazolin-exposed admissions (adjusted odds ratio, 2.44; 95% CI, 1.25-4.76; P < 0.001).

IMPLICATIONS

Cefazolin exhibits high susceptibility for uropathogens commonly implicated in cases of uncomplicated UTI, the most common UTI diagnosis among inpatients. Although ceftriaxone shows a higher susceptibility rate against these common uropathogens, it more than doubles the risk for HOCDI compared with cefazolin. For institutions evaluating opportunities to reduce ceftriaxone use to limit associated collateral damage such as HOCDI, use of cefazolin for uncomplicated UTI may be evaluated by using local susceptibility data.

Association of SARS-CoV-2 status and antibiotic-resistant bacteria with inadequate empiric therapy in hospitalized patients: a US multicenter cohort evaluation (July 2019 - October 2021)

BACKGROUND

Antibiotic usage and antibiotic resistance (ABR) patterns changed during the COVID-19 pandemic. Inadequate empiric antibiotic therapy (IET) is a significant public health problem and contributes to ABR. We evaluated factors associated with IET before and during the COVID-19 pandemic to determine the impact of the pandemic on antibiotic management.

METHODS

This multicenter, retrospective cohort analysis included hospitalized US adults who had a positive bacterial culture (specified gram-positive or gram-negative bacteria) from July 2019 to October 2021 in the BD Insights Research Database. IET was defined as antibacterial therapy within 48 h that was not active against the bacteria. ABR results were based on susceptibility testing and reports from local facilities. Multivariate analysis was used to identify risk factors associated with IET in patients with any positive bacterial culture and ABR-positive cultures, including multidrug-resistant (MDR) bacteria.

RESULTS

Of 278,344 eligible patients in 269 hospitals, 56,733 (20.4%) received IET; rates were higher in patients with ABR-positive (n = 93,252) or MDR-positive (n = 39,000) cultures (34.9% and 45.0%, respectively). Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2)-positive patients had significantly higher rates of IET (25.9%) compared with SARS-CoV-2-negative (20.3%) or not tested (19.7%) patients overall and in the ABR and MDR subgroups. Patients with ABR- or MDR-positive cultures had more days of therapy and longer lengths of stay. In multivariate analyses, ABR, MDR, SARS-CoV-2-positive status, respiratory source, and prior admissions were identified as key IET risk factors.

CONCLUSIONS

IET remained a persistent problem during the COVID-19 pandemic and occurred at higher rates in patients with ABR/MDR bacteria or a co-SARS-CoV-2 infection.

Antimicrobial stewardship for surgical antibiotic prophylaxis and surgical site infections: a systematic review

Background Surgical site infections account for 14-17% of all healthcare-associated infections. Antimicrobial stewardship (AMS) are complementary strategies developed to optimize the use of antimicrobials. Aim to evaluate the effectiveness of AMS in promoting adherence to surgical antibiotic prophylaxis protocols in hospitalized patients, reducing surgical site infection rate and cost-benefit ratio. Method This systematic review of randomized clinical trials, non-randomized clinical trials and before and after studies was performed using Pubmed, Cochrane, Web of Science, Scopus, Embase, Google Scholar and ClinicalTrials.gov, in addition to reference lists of included studies. The risk of bias of studies was measured by the ROBINS-I checklist and the quality of the evidence synthesis by GRADE. Results Fourteen before and after design studies were included. In 85.7% of the studies, AMS was effective in increasing adherence to surgical antibiotic prophylaxis protocols and in 28.5%, there was reduction in surgical site infection rate. Three studies evaluated cost-benefit ratio and found a favorable impact. Eight (57%) studies were at risk of moderate bias and six had severe bias. The evaluation of the synthesis of evidence showed quality ranging from low to very low. Conclusion AMS, such as audit, feedback, education, implementation of a protocol, and a computer-assisted decision support methodology, appear to be effective in promoting adherence to surgical antibiotic prophylaxis protocols, reducing surgical site infection rate with a positive economic impact. However, more studies, particularly randomized clinical trials, are needed to improve the level of evidence of available information on AMS in order to favor decision-making.