Applications of machine learning on electronic health record data to combat antibiotic resistance.

There is growing excitement about the clinical use of artificial intelligence and machine learning technologies. Advancements in computing and the accessibility of machine learning frameworks enable researchers to easily train predictive models using electronic health record data. However, there are several practical factors that must be considered when employing machine learning on electronic health record data. We provide a primer on machine learning and approaches commonly taken to address these challenges. To illustrate how these approaches have been applied to address antimicrobial resistance, we review the use of electronic health record data to construct machine learning models for predicting pathogen carriage or infection, optimizing empiric therapy, and aiding antimicrobial stewardship tasks. Machine learning shows promise in promoting the appropriate use of antimicrobials, although clinical deployment is limited. We conclude by describing potential dangers of, and barriers to, implementation of machine learning models in the clinic.

Impact of Metagenomic Next-Generation Sequencing of Bronchoalveolar Lavage Fluid on Antimicrobial Stewardship in Patients With Lower Respiratory Tract Infections: A Retrospective Cohort Study.

BACKGROUND: The impact of metagenomic next-generation sequencing (mNGS) on antimicrobial stewardship in patients with lower respiratory tract infections (LRTIs) is still unknown. METHODS: This retrospective cohort study included patients who had LRTIs diagnosed and underwent bronchoalveolar lavage between September 2019 and December 2020. Patients who underwent both mNGS and conventional microbiologic tests were classified as the mNGS group, while those with conventional tests only were included as a control group. A 1:1 propensity score match for baseline variables was conducted, after which changes in antimicrobial stewardship between the 2 groups were assessed. RESULTS: A total of 681 patients who had an initial diagnosis of LRTIs and underwent bronchoalveolar lavage were evaluated; 306 patients were finally included, with 153 in each group. mNGS was associated with lower rates of antibiotic escalation than in the control group (adjusted odds ratio, 0.466 [95% confidence interval, .237-.919]; P = .02), but there was no association with antibiotic de-escalation. Compared with the control group, more patients discontinued the use of antivirals in the mNGS group. CONCLUSIONS: The use of mNGS was associated with lower rates of antibiotic escalation and may facilitate the cessation of antivirals, but not contribute to antibiotic de-escalation in patients with LRTIs.

Antibiotics on Demand: Advances in Asynchronous Telemedicine Call for Increased Antibiotic Surveillance.

The rapid growth of telehealth services has brought about direct-to-consumer telemedicine platforms, enabling patients to request antibiotics online without a virtual or face-to-face consultation. While telemedicine aims to enhance accessibility, this trend raises significant concerns regarding appropriate antimicrobial use and patient safety. In this viewpoint, we share our first-hand experience with 2 direct-to-consumer platforms, where we intentionally sought inappropriate antibiotic prescriptions for nonspecific symptoms strongly indicative of a viral upper respiratory infection. Despite the lack of clear necessity, requested antibiotic prescriptions were readily transmitted to our local pharmacy following a simple monetary transaction. The effortless acquisition of patient-selected antibiotics online, devoid of personal interactions or consultations, underscores the urgent imperative for intensified antimicrobial stewardship initiatives led by state and national public health organizations in telehealth settings. By augmenting oversight and regulation, we can ensure the responsible and judicious use of antibiotics, safeguard patient well-being, and preserve the efficacy of these vital medications.

The use of long-term antibiotics for suppression of bacterial infections.

Suppressive antibiotic therapy is prescribed when a patient has an infection that is presumed to be incurable by a defined course of therapy or source control. The cohort receiving suppressive antibiotic therapy is typically highly comorbid and the infections often involve retained prosthetic material. In part due to a lack of clear guidelines regarding the use of suppressive antibiotics, and in part due to the complex nature of the infections in question, patients are often prescribed suppressive antibiotics for extremely long, if not indefinite, courses. The risks of prolonged antibiotic exposure in this context are not fully characterised, but they include adverse drug effects ranging from mild to severe, the development of antibiotic resistant organisms and perturbations of the gastrointestinal microbiome. In this narrative review we present the available evidence for the use of suppressive antibiotic therapy in four common indications, examine the gaps in the current literature and explore the known and potential risks of this therapy. We also make suggestions for improving the quality of evidence in future studies, particularly by highlighting the need for a standardised term to describe the use of long-courses of antibiotics to suppress hard-to-treat infections.

Raising AWaRe-ness of Antimicrobial Stewardship Challenges in Pediatric Emergency Care: Results from the PERFORM Study Assessing Consistency and Appropriateness of Antibiotic Prescribing Across Europe.

BACKGROUND: Optimization of antimicrobial stewardship is key to tackling antimicrobial resistance, which is exacerbated by overprescription of antibiotics in pediatric emergency departments (EDs). We described patterns of empiric antibiotic use in European EDs and characterized appropriateness and consistency of prescribing. METHODS: Between August 2016 and December 2019, febrile children attending EDs in 9 European countries with suspected infection were recruited into the PERFORM (Personalised Risk Assessment in Febrile Illness to Optimise Real-Life Management) study. Empiric systemic antibiotic use was determined in view of assigned final "bacterial" or "viral" phenotype. Antibiotics were classified according to the World Health Organization (WHO) AWaRe classification. RESULTS: Of 2130 febrile episodes (excluding children with nonbacterial/nonviral phenotypes), 1549 (72.7%) were assigned a bacterial and 581 (27.3%) a viral phenotype. A total of 1318 of 1549 episodes (85.1%) with a bacterial and 269 of 581 (46.3%) with a viral phenotype received empiric systemic antibiotics (in the first 2 days of admission). Of those, the majority (87.8% in the bacterial and 87.0% in the viral group) received parenteral antibiotics. The top 3 antibiotics prescribed were third-generation cephalosporins, penicillins, and penicillin/ß-lactamase inhibitor combinations. Of those treated with empiric systemic antibiotics in the viral group, 216 of 269 (80.3%) received ≥1 antibiotic in the "Watch" category. CONCLUSIONS: Differentiating bacterial from viral etiology in febrile illness on initial ED presentation remains challenging, resulting in a substantial overprescription of antibiotics. A significant proportion of patients with a viral phenotype received systemic antibiotics, predominantly classified as WHO Watch. Rapid and accurate point-of-care tests in the ED differentiating between bacterial and viral etiology could significantly improve antimicrobial stewardship.

Individualized Antibiotic Plans as a Quality Improvement Initiative to Reduce Carbapenem Use for Hematopoietic Cell Transplant Patients at a Freestanding Pediatric Hospital.

BACKGROUND: Providers must balance effective empiric therapy against toxicity risks and collateral damage when selecting antibiotic therapy for patients receiving hematopoietic cell transplant (HCT). Antimicrobial stewardship interventions during HCT are often challenging due to concern for undertreating potential infections. METHODS: In an effort to decrease unnecessary carbapenem exposure for patients undergoing HCT at our pediatric center, we implemented individualized antibiotic plans (IAPs) to provide recommendations for preengraftment neutropenia prophylaxis, empiric treatment of febrile neutropenia, and empiric treatment for hemodynamic instability. We compared monthly antibiotic days of therapy (DOT) adjusted per 1000 patient-days for carbapenems, antipseudomonal cephalosporins, and all antibiotics during two 3-year periods immediately before and after the implementation of IAPs to measure the impact of IAP on prescribing behavior. Bloodstream infection (BSIs) and Clostridioides difficile (CD) positivity test rates were also compared between cohorts. Last, providers were surveyed to assess their experience of using IAPs in antibiotic decision making. RESULTS: Overall antibiotic use decreased after the implementation of IAPs (monthly reduction of 19.6 DOT/1000 patient-days; P = .004), with carbapenems showing a continuing decline after IAP implementation. BSI and CD positivity rates were unchanged. More than 90% of providers found IAPs to be either extremely or very valuable for their practice. CONCLUSIONS: Implementation of IAPs in this high-risk HCT population led to reduction in overall antibiotic use without increase in rate of BSI or CD test positivity. The program was well received by providers.

Pediatric Antimicrobial Stewardship Programs Reduce Antibiotic Use at Combined Adult-Pediatric Hospitals.

Implementation of dedicated pediatric antimicrobial stewardship programs (ASPs) at two combined adult-pediatric hospitals with existing ASPs was associated with sustained decreases in pediatric antibiotic use (AU) out of proportion to declines seen in adult inpatient units. ASPs in combined hospitals may not detect excessive pediatric AU without incorporating pediatric expertise.

Antibiotic Prescribing Patterns for Respiratory Tract Illnesses Following the Conclusion of an Education and Feedback Intervention in Primary Care.

BACKGROUND: A study previously conducted in primary care practices found that implementation of an educational session and peer comparison feedback was associated with reduced antibiotic prescribing for respiratory tract diagnoses (RTDs). Here, we assess the long-term effects of this intervention on antibiotic prescribing following cessation of feedback. METHODS: RTD encounters were grouped into tiers based on antibiotic prescribing appropriateness: tier 1, almost always indicated; tier 2, possibly indicated; and tier 3, rarely indicated. A χ2 test was used to compare prescribing between 3 time periods: pre-intervention, intervention, and post-intervention (14 months following cessation of feedback). A mixed-effects multivariable logistic regression analysis was performed to assess the association between period and prescribing. RESULTS: We analyzed 260 900 RTD encounters from 29 practices. Antibiotic prescribing was more frequent in the post-intervention period than in the intervention period (28.9% vs 23.0%, P < .001) but remained lower than the 35.2% pre-intervention rate (P < .001). In multivariable analysis, the odds of prescribing were higher in the post-intervention period than the intervention period for tier 2 (odds ratio [OR], 1.19; 95% confidence interval [CI]: 1.10-1.30; P < .05) and tier 3 (OR, 1.20; 95% CI: 1.12-1.30) indications but was lower compared to the pre-intervention period for each tier (OR, 0.66; 95% CI: 0.59-0.73 tier 2; OR, 0.68; 95% CI: 0.61-0.75 tier 3). CONCLUSIONS: The intervention effects appeared to last beyond the intervention period. However, without ongoing provider feedback, there was a trend toward increased prescribing. Future studies are needed to determine optimal strategies to sustain intervention effects.

Rapid diagnostic tests and antimicrobial stewardship programs for the management of bloodstream infection: What is their relative contribution to improving clinical outcomes? A systematic review and network meta-analysis.

BACKGROUND: Evidence about the clinical impact of rapid diagnostic tests (RDT) for the diagnosis of bloodstream infections is limited, and whether RDT are superior to conventional blood cultures (BC) embedded within antimicrobial stewardship programs (ASP) is unknown. METHODS: We performed network meta-analyses (NMA) using results from studies of patients with bloodstream infection with the aim of comparing the clinical impact of RDT (applied on positive BC broth or whole blood) to conventional BC, both assessed with and without ASP with respect to mortality, length of stay (LOS) and time to optimal therapy (TOT). RESULTS: Eighty-eight papers were selected, including 25,682 patient encounters. There was an appreciable amount of statistical heterogeneity within each meta-analysis. The NMA showed a significant reduction in mortality associated with the use of RDT + ASP vs BC alone (OR 0.72, 95%CI 0.59, 0.87) and with the use of RDT + ASP vs BC + ASP (OR 0.78 95%CI 0.63, 0.96). No benefit in survival was found associated with the use of RDT alone nor with BC + ASP compared to BC alone. A reduction in LOS was associated with RDT + ASP vs BC alone (0.91, 95%CI 0.84, 0.98) while no difference in LOS was shown between any other groups. A reduced TOT was shown when RDT + ASP was compared to BC alone (-29 h, 95%CI -35, -23), BC + ASP (-18 h, 95%CI -27, -10) and to RDT alone (-12 h, 95%CI -20, -3). CONCLUSION: The use of RDT + ASP may lead to a survival benefit even when introduced in settings already adopting effective ASP in association with conventional BC.

Influence of Antibiotic Exposure Intensity on the Risk of Clostridioides difficile Infection.

BACKGROUND: Antibiotics are a strong risk factor for Clostridioides difficile infection (CDI), and CDI incidence is often measured as an important outcome metric for antimicrobial stewardship interventions aiming to reduce antibiotic use. However, risk of CDI from antibiotics varies by agent and dependent on the intensity (i.e., spectrum and duration) of antibiotic therapy. Thus, the impact of stewardship interventions on CDI incidence is variable, and understanding this risk requires a more granular measure of intensity of therapy than traditionally used measures like days of therapy (DOT). METHODS: We performed a retrospective cohort study to measure the independent association between intensity of antibiotic therapy, as measured by the antibiotic spectrum index (ASI), and hospital-associated CDI (HA-CDI) at a large academic medical center between January 2018 and March 2020. We constructed a marginal Poisson regression model to generate adjusted relative risks for a unit increase in ASI per antibiotic day. RESULTS: We included 35,457 inpatient encounters in our cohort. Sixty-eight percent of patients received at least one antibiotic. We identified 128 HA-CDI cases, which corresponds to an incidence rate of 4.1 cases per 10,000 patient-days. After adjusting for known confounders, each additional unit increase in ASI per antibiotic day is associated with 1.09 times the risk of HA-CDI (Relative Risk = 1.09, 95% Confidence Interval: 1.06 to 1.13). CONCLUSIONS: ASI was strongly associated with HA-CDI and could be a useful tool in evaluating the impact of antibiotic stewardship on HA-CDI rates, providing more granular information than the more commonly used days of therapy.

Potential Sexual Transmission of Antifungal-Resistant Trichophyton indotineae.

We describe a case of tinea genitalis in an immunocompetent woman in Pennsylvania, USA. Infection was caused by Trichophyton indotineae potentially acquired through sexual contact. The fungus was resistant to terbinafine (first-line antifungal) but improved with itraconazole. Clinicians should be aware of T. indotineae as a potential cause of antifungal-resistant genital lesions.

Difficult-to-treat (DTR) Pseudomonas aeruginosa harboring Verona-Integron metallo-ß-lactamase (blaVIM): infection management and molecular analysis.

Pseudomonas aeruginosa harboring Verona Integron-encoded metallo-ß-lactamase enzymes (VIM-CRPA) have been associated with infection outbreaks in several parts of the world. In the US, however, VIM-CRPA remain rare. Starting in December 2018, we identified a cluster of cases in our institution. Herein, we present our epidemiological investigation and strategies to control/manage these challenging infections. This study was conducted in a large academic healthcare system in Miami, FL, between December 2018 and January 2022. Patients were prospectively identified via rapid molecular diagnostics when cultures revealed carbapenem-resistant P. aeruginosa. Alerts were received in real time by the antimicrobial stewardship program and infection prevention teams. Upon alert recognition, a series of interventions were performed as a coordinated effort. A retrospective chart review was conducted to collect patient demographics, antimicrobial therapy, and clinical outcomes. Thirty-nine VIM-CRPA isolates led to infection in 21 patients. The majority were male (76.2%); the median age was 52 years. The majority were mechanically ventilated (n = 15/21; 71.4%); 47.6% (n = 10/21) received renal replacement therapy at the time of index culture. Respiratory (n = 20/39; 51.3%) or bloodstream (n = 13/39; 33.3%) were the most common sources. Most infections (n = 23/37; 62.2%) were treated with an aztreonam-avibactam regimen. Six patients (28.6%) expired within 30 days of index VIM-CRPA infection. Fourteen isolates were selected for whole genome sequencing. Most of them belonged to ST111 (12/14), and they all carried blaVIM-2 chromosomally. This report describes the clinical experience treating serious VIM-CRPA infections with either aztreonam-ceftazidime/avibactam or cefiderocol in combination with other agents. The importance of implementing infection prevention strategies to curb VIM-CRPA outbreaks is also demonstrated.

Diagnosis and Treatment of Helicobacter pylori Infection.

The last 5 years have seen major shifts in defining whom to test and how to treat Helicobacter pylori infection. Peptic ulcer has changed from a chronic disease to a one-off condition, and countries with a high incidence of gastric cancer have begun implementing population-wide screening and treatment. A proactive approach to testing and treatment of H. pylori is now recommended, including outreach to family members of individuals diagnosed with active infection as well as high-risk local populations such as immigrants from high-risk countries. Increasing antimicrobial resistance has resulted in an overall decline in treatment success, causing a rethinking of the approach to development of treatment guidelines as well as the need to adopt the principles of antibiotic usage and antimicrobial stewardship. Required changes include abandoning empiric use of clarithromycin, metronidazole, and levofloxacin triple therapies. Here, we discuss these transformations and give guidance regarding testing and use of therapies that are effective when given empirically.

An exception-reporting approach for wound swab culture: effect on post-report antibiotic initiation.

A prior analysis suggested that wound swab culture (WSC) results were driving unnecessary antibiotic use in patients who were not already receiving treatment. As a quality-improvement initiative, our laboratory introduced an "exception-reporting" protocol on 1 March 2023, whereby typical wound pathogens susceptible to recommended empiric therapy (flucloxacillin/cefalexin) were not reported, and a comment was provided, stating no significant resistant organisms had been detected. Full results were available to clinicians on request. Cultures falling outside protocol criteria were reported in the standard fashion. This analysis sought to assess the effect of exception-reporting on post-report antibiotic initiation (PRAI). All community WSC results were matched to antibiotic dispensing records from October 2021 to December 2023. Sampling without treatment pre-report was termed "test and wait" (TaW). Following TaW, PRAI was identified if antibiotics were started within 5 days post-report. There were 1,819 and 764 WSCs received in the pre-change and post-change periods, respectively, where an initial TaW approach had been taken and an organism eligible for exception-reporting had been isolated. In the post-change period, 407 (53.3%) met the criteria and were exception-reported. PRAI occurred in 901 (49.5%) pre-change samples, compared to 102 (25.1%, P < 0.01) with exception-reporting. There was no detectable increase in hospitalization or repeat WSC collection in the 30 days following exception-reporting. Exception-reporting was associated with a markedly reduced proportion of patients being initiated on antibiotics following WSC where an organism had been isolated. The naming of organisms in reports appears to drive unnecessary antibiotic prescribing in many patients. These results require confirmation in other jurisdictions. IMPORTANCE: Wound swab culture is a high-volume test performed in clinical microbiology laboratories. In this analysis, we have shown that an alternative approach to reporting positive wound swab cultures has resulted in a large reduction in post-report antibiotic initiation, suggesting that the current standard method of reporting generates considerable unnecessary antibiotic use. If these findings are replicated elsewhere, wider adoption of this reporting would represent an opportunity for many clinical microbiology laboratories to have a significant impact on community antimicrobial stewardship.

Antibiotic Overtreatment of Presumed Urinary Tract Infection Among Children with Spina Bifida.

OBJECTIVE: To identify factors associated with overtreatment of presumed urinary tract infection (UTI) among children with spina bifida using such criteria. STUDY DESIGN: A retrospective review of children with spina bifida (age <21 years) evaluated in the Emergency Department (ED) at a single institution was performed. Patients with a urinalysis (UA) performed who were reliant on assisted bladder emptying were included. The primary outcome was overtreatment, defined as receiving antibiotics for presumed UTI but ultimately not meeting spina bifida UTI criteria (≥2 urologic symptoms plus pyuria and urine culture growing >100k CFU/mL). The primary exposure was whether the components of the criteria available at the time of the ED visit (≥2 urologic symptoms plus pyuria) were met when antibiotics were initiated. RESULTS: Among 236 ED encounters, overtreatment occurred in 80% of cases in which antibiotics were initiated (47% of the entire cohort). Pyuria with <2 urologic symptoms was the most important factor associated with overtreatment (OR 9.6). Non-Hispanic White race was associated with decreased odds of overtreatment (OR 0.3). CONCLUSIONS: Overtreatment of presumed UTI among patients with spina bifida was common. Pyuria, which is not specific to UTI in this population, was the main driver of overtreatment. Symptoms are a cornerstone of UTI diagnosis among children with spina bifida, should be collected in a standardized manner, and considered in a decision to treat.

Bacteriuria in patients with stented ureters: predictors of infection in patients presenting to the hospital and when not to treat.

PURPOSE: Patients with ureteric stents have symptoms that overlap with infection symptoms. Thus, clinicians unnecessarily give antibiotics to stented patients with bacteriuria despite guidelines. In stented patients, little is known about risk factors for developing bacteriuria or urosepsis. The objectives were to identify the frequency and risk factors for developing bacteriuria and urosepsis in patients with stents. METHODS: In this retrospective cohort study, we reviewed patients with ureteric stents placed or exchanged over 1 year. We examined associations between bacteriuria or urosepsis and host risk factors. Univariable and multivariable logistic analyses were performed. RESULTS: Of 286 patients (mean age: 57.2 years), 167 (58.4%) were male. The main stent indications were stone, stricture, cancer and extrinsic compression. The median stented period was 61 days. The frequency of bacteriuria was 59/286 (21%). ASA status 3 and 4 had 5 times the odds of having bacteriuria relative to ASA status 1. Stent duration > 2 months had 5.5 times the odds relative to ≤ 2 months. Urosepsis was infrequent, 13/286 (4.5%). Five patients had bacteraemia. A stent duration over 2 months had nearly 6 times the odds of urosepsis. CONCLUSION: ASA status higher than 2 and stent time greater than 2 months raise the odds of developing bacteriuria. A stent duration longer than 2 months was the only predictor of urosepsis. Though 21% of patients had bacteriuria, 4.5% had urosepsis. Hence, bacteriuria without sepsis should not be treated with antibiotics, thus aiding antimicrobial stewardship.

A tale of 2 digital hospitals: A qualitative study of antimicrobial stewardship teams.

AIMS: We aim to examine and understand the work processes of antimicrobial stewardship (AMS) teams across 2 hospitals that use the same digital intervention, and to identify the barriers and enablers to effective AMS in each setting. METHODS: Employing a contextual inquiry approach informed by the Systems Engineering Initiative for Patient Safety (SEIPS) model, observations and semistructured interviews were conducted with AMS team members (n = 15) in 2 Australian hospitals. Qualitative data analysis was conducted, mapping themes to the SEIPS framework. RESULTS: Both hospitals utilized similar systems, however, they displayed variations in AMS processes, particularly in postprescription review, interdepartmental AMS meetings and the utilization of digital tools. An antimicrobial dashboard was available at both hospitals but was utilized more at the hospital where the AMS team members were involved in the dashboard's development, and there were user champions. At the hospital where the dashboard was utilized less, participants were unaware of key features, and interoperability issues were observed. Establishing strong relationships between the AMS team and prescribers emerged as key to effective AMS at both hospitals. However, organizational and cultural differences were found, with 1 hospital reporting insufficient support from executive leadership, increased prescriber autonomy and resource constraints. CONCLUSION: Organizational and cultural elements, such as executive support, resource allocation and interdepartmental relationships, played a crucial role in achieving AMS goals. System interoperability and user champions further promoted the adoption of digital tools, potentially improving AMS outcomes through increased user engagement and acceptance.

Determinants of pharmacists' confidence to participate in antimicrobial stewardship: A confirmatory factor analysis.

AIM: Pharmacists are essential members of hospital antimicrobial stewardship (AMS) teams. A lack of self-perceived confidence can limit pharmacists' involvement and contributions. Pharmacists working in AMS have reported a lack of confidence. There is currently a lack of validated measures to assess pharmacists' self-perceived confidence when working in AMS and contributors to this confidence. This study aimed to identify variables contributing to pharmacist self-perceived confidence and validate an AMS hospital pharmacist survey tool using confirmatory factor analysis (CFA). METHODS: Responses from a survey of Australian and French hospital pharmacists were used to undertake CFA and path analysis on factors related to pharmacists' self-perceived confidence. It was hypothesized that pharmacists' self-perceived confidence would be impacted by time working in AMS, perceived importance of AMS programmes, perceived barriers to participating in AMS and current participation. RESULTS: CFA demonstrated a good model fit between the factors. Items included in the model loaded well to their respective factors with acceptable reliability. Path analysis demonstrated that time working in AMS had a significant impact on pharmacists' self-perceived confidence, while perceived barriers had a negatively significant relationship. Pharmacy participation in AMS and perceived importance of AMS programmes had a non-significant impact. CONCLUSION: Findings demonstrated that the survey tool showed good validity and identified factors that can impact pharmacists' self-perceived confidence when working in hospital AMS programmes. Having a validated survey tool can identify factors that can reduce pharmacists' self-perceived confidence. Strategies can then be developed to address these factors and subsequently improve pharmacists' self-perceived confidence.

The Utility of Prophylactic Antibiotics for Laparoscopic Pyloromyotomy.

INTRODUCTION: Laparoscopic pyloromyotomy (LP) for the treatment of infantile hypertrophic pyloric stenosis (IHPS) is a clean case with low expected rates of postoperative surgical site infection (SSI). Previous studies have shown a low risk of SSI following LP but also large variations in the utilization of prophylactic antibiotics. The goal of this study was to review the use of preoperative antibiotics for LP and to compare this with SSI incidence. METHODS: We performed a retrospective single-center analysis of patients undergoing LP for infantile hypertrophic pyloric stenosis at a large quaternary children's hospital from January 2017 to June 2020. Subjects were <4 mo old. Exclusion criteria were those lost to follow-up within 30 d postoperatively and those who required open conversion intraoperatively. Statistical analysis was performed using Fisher's exact test, two-tailed independent t-tests, and descriptive statistics. RESULTS: Two-hundred twenty-seven patients were included, mean population age was 5.7 wk, and 81.1% were male. Preoperative antibiotics were administered in 39% of patients. Only 1.3% (n = 3) of all patients developed an SSI within 30 d of their operation. Analysis between patients who received preoperative antibiotics and those who did not revealed no difference in age (5.72 wk versus 5.72 wk, t (225) = 0.38, P = 0.70), sex (41% of males versus 32% of females, P = 0.39), length of stay (t(225) = -0.94, P = 0.35), or postoperative SSI (1.1% versus 1.4%, P > 0.999). Large variability was noted in antibiotic utilization by surgeon. CONCLUSIONS: In patients undergoing LP, there was no difference in SSI rates whether or not patients received preoperative antibiotics and, there is large variation in utilization. Measures are needed to decrease usage of prophylactic antibiotics before LP.

Timing of Acquisition of Methicillin-Resistant Staphylococcus aureus Nasal Carriage: Can we Limit Repeat Screening?

INTRODUCTION: Broad-spectrum empiric antibiotics are routinely administered to hospitalized patients with potential infections. These antibiotics provide protection; however, they come with their own negative effects. The utility of Methicillin-resistant Staphylococcus aureus (MRSA) polymerase chain reaction (PCR) nasal screening to steward anti-MRSA empiric antibiotics in hospitalized patients is established. With this current study, we look to determine the optimal frequency of MRSA nasal testing to help limit unnecessary testing consistent with the efforts of Choosing Wisely. We hypothesize that MRSA PCR nasal swab conversion will be low within the first 2 wk after index swab collection. METHODS: We performed a single-center retrospective chart review of all adult patient encounters from October 2019-July 2021 with MRSA PCR nasal testing. We excluded duplicate patient encounters. Further exclusion criteria included patients with a single MRSA PCR swab and those who tested positive for MRSA colonization on their index swab. We evaluated how many conversions from negative to positive there were, and the timing of those relative to those that did not develop colonization while in the hospital. RESULTS: 263 patients had multiple MRSA nares screening. 215 patients had 2 swab collections, 35 patients had 3 swab collections, 9 patients had 4 swab collections, and 4 patients had 5 swab collections. 14 converted from negative to positive. The time of conversions ranged from within 0-36 d, with an overall cumulative conversion of 5%. The rate of cumulative conversion from one week was 1.9%, for 2 wk it was 3.4%. CONCLUSIONS: Findings suggest that MRSA PCR nasal swab conversion is unlikely to occur within 2 wk. Therefore, to optimize resources, further investigation should be conducted to target guidelines as well as systems to limit repeat swab testing. We will investigate the utility of this after implementation.