Nasal MRSA Research Articles

1191. The Implementation of Nasal MRSA PCR for Pneumonia and Association with Antibiotic Use and Clinical Outcomes

Abstract Background Nasal MRSA PCR testing has been successfully implemented at many centers and limits vancomycin exposure among hospitalized patients with pneumonia. There are few studies of a Best Practice Alert (BPA) to direct nasal MRSA PCR use and vancomycin de-escalation in the absence of other stewardship oversight. On 1/2/2020, nasal MRSA PCR and a BPA were implemented at our institution. Providers ordering vancomycin for patients with an indication of pneumonia or undifferentiated sepsis were directed to order a nasal MRSA PCR and recommended to stop vancomycin if negative (Figure 1). Our aim was to examine the impact of BPAs implementation on vancomycin duration among patients with suspected pneumonia. Methods A retrospective chart review was conducted among hospitalized patients without prior MRSA PCR performed during their admission who had a listed indication of pneumonia or sepsis at the time of vancomycin order. Patients were categorized into “pre” (9/17/2018 – 1/1/2020) and “post” (1/2/2020 – 3/20/2021) cohorts based on date of vancomycin order. Demographics, comorbidities, and antibiotic duration were electronically extracted. Uni- and multivariable logistic models were used to examine the proportion of patients in the pre and post cohorts whose vancomycin was stopped within 24 hours of initial order. Results A total of 2,195 patients were included, 1210 in the pre-intervention and 985 in the post-intervention cohort. After BPA implementation, 771/985 (78%) patients received a nasal MRSA PCR. Vancomycin was discontinued within 24 hours after initiation in 384/1210 (32%) patients pre-intervention and 559/985 (57%) patients post-intervention (adjusted OR 2.92 [95% CI 2.44 – 3.49], p < 0.001) (Table 1). Although “high risk” patient factors (e.g. need for mechanical ventilation) were associated with longer durations, vancomycin duration was significantly shorter in the post-implementation cohort for all “high risk” sub-groups (Figure 2). Conclusion BPA directed nasal MRSA PCR testing and vancomycin de-escalation effectively shortened duration of therapy among patients with suspected pneumonia. Utilizing a BPA directed approach can improve decision efficiency and allow valuable stewardship team resources to be allocated elsewhere. Disclosures All Authors: No reported disclosures

1790. Dethroning Vancomycin: A Multifaceted Stewardship Approach to Reduce Vancomycin in an Academic Medical Center

Abstract Background Vancomycin is a broadly used antimicrobial, and from 2014-2022 represented the most used antibiotic at our academic medical center. Since 2015, the stewardship program has introduced several measures to optimize vancomycin use including pharmacy consultation, addition of MRSA nares PCR testing, embedding MRSA nares PCR order into vancomycin order panel, and introducing an electronic medical record (EMR) best practice alert to assist providers in identifying patients eligible for vancomycin discontinuation. The impact of each of these interventions are described. Methods This is a retrospective, single academic center, comparison of vancomycin utilization over time, following the introduction of various stewardship measures. Each intervention remained in place during subsequent periods. Wilcoxon rank sum was used for analysis. Period 1 (P1): 4/2015-12/2016 vancomycin pharmacy consultPeriod 2 (P2): 1/2017-6/2019 pharmacists authorized to order Nasal MRSA PCRPeriod 3 (P3): 7/2019-2/2020 embed nasal MRSA PCR into consult panelPeriod 4 (P4): 2/2020-3/2022 addition of automated EMR time-out Results Each period of vancomycin optimization was associated with a statistically significant decrease in vancomycin length of therapy (LOT) in days, when compared to the period before it (P1 vs P2, p< 0.0001; P2 vs P3, p< 0.0001; P3 vs P4, p< 0.0001). Overall institution vancomycin consumption, expressed as monthly days of therapy (DOT)/1000 patient days (PD) also decreased over time, starting with period 3 (P1 vs P2, p=0.4812; P2 vs P3, p=0.0003; P3 vs P4, p=0.0019) (Table 1). Table 1Vancomycin utilization trends over 4 periods of stewardship intervention. Conclusion Decreasing vancomycin at an academic medical center is challenging and takes a multifaceted approach with continued efforts over time to maintain a steady downward trend for utilization. These combined efforts have led to vancomycin no longer being the most commonly prescribed antibiotic at our institution. Disclosures All Authors: No reported disclosures.

The Clinical Importance of Preoperative Rectal Swabs in Patients after Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

Background: Surgical site infections are among the most common healthcare-associated infections, especially in patients undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). The aim of this retrospective study was to examine postoperative infectious complications according to preoperative screening findings of nasal and rectal swabs. Methods: Two hundred four consecutive patients received nasal and rectal swab examination for multidrug-resistant (MDR) bacteria within 30 days before the operation in patients where CRS and HIPEC were planned. Inclusion criteria were as follows: confirmed peritoneal metastases (histologically and/or cytologically); age under 85 years; adequate renal, liver, and bone marrow function; no sign of infection preoperatively; resectable disease; and CRS and HIPEC procedure. If surgical site infection occurred, the microbial spectrum of the site was assessed. One hundred twenty-one patients (63 female [52.1%] and 58 male [47.9%]) met the criteria and were further analyzed retrospectively. Statistical correlations between postoperative complications and risk factors were investigated by univariate and multivariate analysis. Results: Postoperative complications in total were observed in 57 patients (47.1%) with major complications (Clavien-Dindo grades 3–4) in 15 patients (12.4%) and infectious complications in 37 (30.6%) patients. The overall prevalence of nasal MRSA carriage was 3.28%, and the overall prevalence of rectal MDR bacteria carriage was 10.7%. In propensity score analysis, colonized patients compared to noncolonized patients showed increased total complications (CD1–5, p = 0.025), infectious complications (p = 0.028), surgical site infections (p = 0.022) as well as pneumonia (p = 0.016). Multivariate analysis showed that in addition to preoperative rectal colonization, American Society of Anesthesiologists score was a risk factor for postoperative complications. Conclusions: Preoperative 3-MRGN and vancomycin-resistant enterococcus colonization were associated with increased complications and surgical site infections. Special antimicrobial treatment pathways are necessary for these patients to reduce postoperative complications due to colonization.

P18 Prevalence and risk factors for nasal colonization with MRSA among children attending immunization in Port Harcourt, Nigeria

Background Staphylococcus aureus is a bacterial agent commonly found on the skin and anterior nares of healthy individuals. There has been an increase in the carriage of MRSA globally. Nasal MRSA colonization is a public health problem because it is a significant risk factor for staphylococcal infection. This study explores the prevalence, antibiotic susceptibility profile and risk factors for nasal colonization of healthy children under 5 years old attending immunization.MethodsNasal swabs were collected from 176 healthy children 0–60 months old, attending routine immunization in Port Harcourt. Questionnaires covering demographic information and potential risk factors were administered to caregivers of the children. Collected samples were tested for the presence of MSSA and MRSA. Antibiotic susceptibility testing was carried out on all MSSA and MRSA samples.ResultsThe prevalence of MSSA and MRSA were 10/176 (5.68%) and 48/176 (27.3%), respectively. The MDR rate among the 58 S. aureus samples was 53/58 (91.38%). Children who had an ear infection in the preceding 1 month were at a higher risk of being colonized with MRSA at P = 0.048 (95% CI). There was also a significant association P = 0.036 (95% CI) between the educational status of mother and nasal colonization, with higher educational status reducing the chances of association.ConclusionsThere is a rising prevalence of MRSA colonization and MDR strains. A history of ear infections and a poor level of education of the mother were identified as significant risk factors for MRSA colonization.Table 1.Association between potential risk factors and MRSA carriageFactorsMRSAχ2 P valuepositivenegativeHospitalization0.3770.539f Yes01 No48127Hospital visit0.1400.708 Yes511 No43117RTI0.8630.353 Yes2474 No2454Ear infection4.8600.048* f Yes42 No44126Antibiotic use1.3750.241 Yes935 No3993Family health worker0.3040.582 Yes510 No43118Smoker1.6380.243f Yes213 No46114*Significant at 95%; fFisher's exact test.

What is the validity of nasal MRSA swab screening in predicting culture-positive MRSA?

What is the validity of nasal MRSA swab screening in predicting culture-positive MRSA?

Methicillin Resistant <i>Staphylococcus aureus</i> in Pigs and Pig Breeders in Three Regions of Cameroon

The spread of antibiotic resistance, whether in the community or in the hospital, has recently become a major public health problem. Moreover, livestock seems to be a reservoir of resistant microorganisms such as porcine methicillin resistant Staphylococcus aureus (P-MRSA) whose carriage and transmission was mainly demonstrated in persons with occupational exposure to pigs. Much uncertainty remains about the public health implications of P-MRSA. To address concerns that exist regarding the zoonotic risk that pig carriers pose to breeders, the prevalence of P-MRSA in pigs and pig breeders was determined among 152 pig breeders in three regions of Cameroon. Materials and Method: Participants in this study came from Adamawa, Far North and Littoral regions of Cameroon. A total of 152 pig breeders or farm workers participated in this study. After having collected some social and cultural data with the aid of a questionnaire, nasal swabs were collected from pigs (n = 275) and their breeders using the standard collection procedures and placed in cooler containing cold accumulators. For each sample, microbiological assays were done as well as antibiotic susceptibility tests. Results: MRSA was isolated from 25 out of 275 pigs sampled (9.09%) and from 32 out of 152 (21.05%) pig breeders sampled; 33 breeders (21.71%) were carriers of S. aureus including 32 MRSA and one MSSA. The prevalence of MRSA nasal carriage was 21.05% ± 6.48. A significant negative association between body protection and nasal carriage of MRSA (OR = 0.29, 95% CI [0.093; 0.93]; p = 0.04) was observed. In each region, similar strains of MRSA were isolated both in pigs and their breeders with the same antibiotic resistant profile. Conclusion: The prevalence of MRSA though not high compared to European countries warrants further research as data on this zoonosis is scarce in our context. As such, transmission of MRSA from pigs to pig breeders or vice-versa constitutes a real danger, and this relationship may be a starting point for MRSA contamination in the community. Moreover, proper use of body protections and antibiotic medications as recommended will be a better protective measure against nasal MRSA carriage.

Clinical and Microbiological Characteristics of Hospital-Acquired Methicillin-Resistant Staphylococcus aureus Bacteremia Caused by a Community-Associated PVL-Negative Strain.

BackgroundST72-SCCmecIV, a community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strain in Korea, originated in the community and has been spreading in health care settings. Herein, we describe the clinical and microbiological characteristics of patients with hospital-acquired MRSA bacteremia (MRSAB) caused by community-associated strains.MethodsWe analyzed hospital-acquired MRSAB cases caused by ST72-SCCmecIV using a prospective cohort of patients with SAB in a tertiary hospital in Korea from July 2008 to December 2018. We compared the clinical and microbiological characteristics of ST72-SCCmecIV with ST5-SCCmecII, a representative hospital-associated genotype strain.ResultsOf the 1782 S. aureus bacteremia (SAB) cases, 628 (35.2%) were hospital-acquired MRSAB. Of the 628 isolates, 431 (68.6%) were ST5-SCCmecII and 152 (24.2%) were ST72-SCCmecIV. Patients with ST72-SCCmecIV were younger than those with ST5-SCCmecII and less likely to have a history of recent surgery, antibiotic treatment, nasal MRSA colonization, and central venous catheter placement. Compared with ST5-SCCmecII, ST72-SCCmecIV isolates were more likely to have vancomycin MICs ≤1.0 mg/L (P < .001). Osteoarticular infection as the site of infection (7.2% [11/152] vs 1.4% [6/431]) was more common in patients with ST72-SCCmecIV. There were no significant differences in the rate of recurrence (≤90 days), persistent bacteremia (≥7 days), or 30- and 90-day mortality rates between the 2 groups.ConclusionsOsteoarticular infections were more prevalent in ST72-SCCmecIV MRSAB. Mortality rates between the ST72-SCCmecIV and ST5-SCCmecII groups were not significantly different.

Predictors of cardiovascular disease in patients with chronic kidney disease VD stage treated with hemodialysis

The aim of the study was to establish the frequency and possible predictors of cardiovascular disease (CVD) in chronic kidney disease (CKD) VD stage patients, treated with hemodialysis, based on results of prospective observation. The prospective observational cohort study included 223 patients with CKD V D stage who were treated with hemodialysis (HD) during 2012-2019. The research was carried out in two stages. At the first stage, main demographic, laboratory and clinical characteristics of patients, including the frequency of CVD, at the time of beginning the study were examined. At the second stage, based on prospective studying of the dynamics of the frequency of CV pathology, an assessment of potential predictors of CVD in CKD V D stage patients treated with HD was made. Patients’ characteristics determined at the beginning of the study were used as possible predictors. The average duration of prospective study was 35.5±17.8 months, cumulative – 579.3 patient-years. For determination of prognostic factors of CVD events, ROC-analysis, univariate and multivariate Cox proportional hazard regression analysis were done. The primary endpoint (newly diagnosed CVDs) was assesses at the end of the study. Statistical processing of the obtained results was performed using the MedCalc Statistical Software, version 19.3. During the study period, a significant increase of all CVD frequency by 80% (р&lt;0.001) was stated, more than twice – of coronary artery disease (CAD; р&lt;0.001) and atrial fibrillation (AF; р=0.0039). The incidence rate of CVD and CAD was 9.8 and 9.15 per 100-patient-years, respectively. The primary endpoint was observed in 92 (41.26%) patients: newly diagnosed CAD – in 53 patients, heart failure – in 12 patients, AF – in 9 patients, acute myocardial infarction – in 8 patients, other heart diseases – in 10 patients. Independent predictors on increased CVD risk in chronic kidney disease VD stage patients treated with hemodialysis are: age over 35 years, use of a central venous catheter as a vascular access during HD initiation, history of nasal MRSA collonization. In the other hand, serum albumin level of more than 36,6 g/l was associated with reduced risk.

1489. Safety and Performance of a Pharmacist-Driven Nasal MRSA PCR Protocol for De-escalation of Empiric Vancomycin for Suspected Pneumonia at an Academic Medical Center

BackgroundLimited published data supports the de-escalation of empiric anti-methicillin resistant Staphylococcus aureus (MRSA) antibiotics for suspected pneumonia upon negative nasal MRSA screening. Besides limited sample sizes, special populations, such as those who are immunocompromised and/or critically ill, have been underrepresented in these reports. We describe real-world efficacy and safety of a pharmacist-driven nasal MRSA PCR testing protocol implemented at Stanford Health Care in May 2018 across a diverse patient population.MethodsThis was an observational cohort study of adult patients who received vancomycin for empiric pneumonia before (PRE) vs after (POST) implementation of a pharmacist-driven nasal MRSA PCR testing protocol (between 05/01/2017 - 08/31/2017 (PRE) and 5/7/2018 - 12/31/2019 (POST). The primary outcome measure was duration of vancomycin administration. Secondary outcomes included time to vancomycin discontinuation, frequency of restarting vancomycin for empiric pneumonia within 7 days, acute kidney injury (defined as “risk” by RIFLE criteria), and MRSA respiratory cultures. Statistical methods are described in Figure A.Figure A. Statistical methods ResultsTotal of 610 patients were included in this study with 116 in the PRE group and 494 in the POST group. Over 40% were critically ill and approximately 37% were immunocompromised in both groups (Table 1). For the primary outcome, median vancomycin duration was significantly shorter in the POST group (1.29 days; 95% CI 1.13-1.45) vs. PRE group (1.98 days; 95% CI 1.49-2.46) (p < 0.0005), a 34.8% reduction (Figure 1). Median vancomycin duration was lower in patients with a negative vs positive nasal MRSA PCR (1.20 days [95% CI 1.08-1.33] vs 2.53 days [95% CI 1.77-3.29], p < 0.0005), a 52.6% reduction (Figure 2). MRSA was recovered in respiratory cultures in 1.7% vs 1.4% in the PRE vs POST groups. One (0.002%) patient had a negative nasal MRSA PCR but culture-confirmed MRSA pneumonia and recovered after completing a treatment course. Secondary safety outcomes were similar between groups (Table 2).Tables 1 and 2: Baseline Characteristics and Secondary Outcomes Figure 1. Primary Outcome: Kaplan–Meier Estimates of Cumulative Active Vancomycin Therapy Before and After Implementation of Nasal MRSA PCR protocol Figure 2. Secondary Outcome: Figure 2. Kaplan–Meier Estimates of Cumulative Active Vancomycin Therapy in Patients with Negative vs Positive Nasal MRSA PCR ConclusionPharmacist-driven nasal MRSA PCR testing is effective and safe in early de-escalation of empiric vancomycin used for pneumonia treatment in a diverse population including critically ill and immunocompromised patients.Disclosures All Authors: No reported disclosures

854. Infection Prevention vs. Antimicrobial Stewardship: Does Nasal Povidone-Iodine Interfere with Methicillin Resistant Staphylococcus aureus (MRSA) Screening?

BackgroundAs part of universal decolonization, intensive care unit (ICU) patients may receive intranasal mupirocin to reduce MRSA infections. However, due to concerns about widespread use of mupirocin promoting resistance, some have proposed a bactericidal antiseptic, povidone-iodine (P-I), as an alternative. There are few data as to whether either agent reduces the sensitivity of MRSA nares screening. This study aimed to discern whether intranasal P-I interferes with MRSA screening via polymerase chain reaction (PCR) and/or culture.MethodsWe performed a prospective proof-of-concept cohort study at our >1200-bed, community-based academic health care system, enrolling 20 patients who screened MRSA-positive by PCR on admission to a medical ICU, medical-surgical ICU, or medical stepdown unit. All patients received twice-daily intranasal P-I (7.5%) for 5 days or until unit discharge. We obtained follow-up nasal MRSA PCR tests after 4-6 days, and confirmed all PCR results with MRSA cultures using CHROMagar™. We calculated sensitivity of MRSA PCR at follow-up using culture as the gold standard.ResultsTwenty patients were enrolled, with a median age of 72 years (range, 53-91). Most (75%) were admitted with active infection, and 40% had known MRSA history. All baseline PCRs were confirmed by positive culture. Patients underwent a mean of 8.1 (range, 4-13) nasal P-I applications prior to follow-up testing. At follow up, 16/20 (80%) remained MRSA-positive via both PCR and culture. Of the 4 patients with negative follow-up results, 1 was both PCR-/culture-, 2 were PCR+/culture- and 1 was PCR-/culture+. All 4 had received ≥1 doses of vancomycin, and one person had received ≥1 doses of linezolid. The sensitivity of MRSA PCR at follow-up was 94%.ConclusionMRSA PCR remains highly sensitive even after multiple applications of P-I, and may be more sensitive than culture. If clinicians wish to screen for MRSA for stewardship or other purposes, receipt of nasal P-I should not be a deterrent. However, the fact that most patients remained culture-positive after 4-13 applications raises concerns that P-I is less effective than mupirocin for clearing nasal colonization. We recommend using quantitative cultures to further investigate the effectiveness of nasal P-I.Disclosures All Authors: No reported disclosures

248. Why so Much Vancomycin and Piperacillin/Tazobactam Usage Given Known Risks of Nephrotoxicity

BackgroundDespite years of published data describing the increased risk of nephrotoxicity with use of vancomycin and piperacillin/tazobactam (VPT), this combination remains one of the most utilized antibiotic combinations at our institution. There is limited data describing the appropriateness of empiric use of this broad-spectrum regimen. Our primary objective was to evaluate the appropriateness of the anti-methicillin resistant Staphylococcus aureus (MRSA), anti-pseudomonal, and anti-anaerobic spectrum of activity for patients empirically treated with this combination. Our secondary objective was to evaluate the appropriateness of diagnostic evaluation in patients started on this combination.MethodsA retrospective cohort study was performed on a random sample of unique patients prescribed the combination of VPT from October 2019 through March 2020. Demographic and clinical data were abstracted from the electronic medical record. Based on predetermined criteria, we evaluated the appropriateness of the spectrum of activity of empiric therapy and the diagnostic evaluation.ResultsOf 100 patients evaluated, 96 patients (96%) received VPT as empiric treatment. The indications for use are shown in Table 1. Pneumonia and soft tissue/bone/joint infections were the most common indications. The appropriateness of anti-MRSA, anti-pseudomonal, and anti-anaerobic therapy is shown in Table 2. In only 35% of patients was the full spectrum of activity appropriate. Of 47 patients treated empirically for pneumonia, 35 (74%) had an order for a respiratory culture and 7 (15%) for a nasal MRSA surveillance culture. Of 30 patients treated empirically for soft tissue//joint infections, wound cultures were obtained in 22 (73%). Nineteen patients underwent surgical intervention, of whom 17 (89%) had cultures obtained.Table 1. Indications for Empiric Vancomycin and Piperacillin/tazobactam Combination Therapy Table 2: Appropriateness of Spectrum of Activity for Empiric Vancomycin and Piperacillin/tazobactam Combination Therapy ConclusionAt our institution VPT use was usually empiric and unnecessarily broad for the syndrome being treated. Microbiologic testing was suboptimal and may have resulted in prolonged therapy. Although interventions aimed at de-escalating VPT are useful, interventions aimed at ensuring appropriate empiric use of this combination and ensuring appropriate diagnostic testing may be just as important.Disclosures All Authors: No reported disclosures

Increasing Mupirocin Resistance Among MRSA Nasal Surveillance Isolates in the Chicago Area

Background: In 2005, our healthcare system began universal admission screening for nasal colonization with MRSA and decolonization of MRSA positive patients with mupirocin. In 2010–2012, we studied the impact of nasal MRSA decolonization and concluded that it does not add benefit when contact precautions are used; plus, it resulted in increased rates of mupirocin resistance up to 9.4% in 2012. In September 2012 routine decolonization of hospitalized patients was discontinued. In the 2 years following discontinuation of mupirocin use for decolonization of MRSA carriers, the rate of mupirocin resistance gradually declined. We undertook a contemporary review of mupirocin resistance rates to ensure that the rates were stable. Methods: NorthShore University HealthSystem, Illinois, consists of 4 hospitals in the northern suburbs of Chicago, with 750 beds and 60,000 annual admissions. Admission nasal swab samples were collected from at-risk hospitalized patients based on a risk-adjusted algorithm. Nasal swabs were tested using the BD MAX MRSA assay. Positive samples were cultured onto BD BBL CHROMagar MRSA to recover the organism and were tested for the mupA gene, which confers high-level mupirocin resistance using an in-house PCR test. Data for mupirocin orders were provided by the pharmacy. Results: Mupirocin resistance rates and prescription orders are shown in Figs. 1 and 2. Conclusions: Mupirocin resistance rates plateaued between 2012 and 2014 and then increased from 9.1% in 2015 to 18.1% in 2019, despite discontinuation of routine decolonization of hospitalized patients. The reason for the increase is unclear; inpatient mupirocin orders were stable from 2015 to 2017.Funding: NoneDisclosures: None

Screening for Multidrug-Resistant Organisms in a Tertiary-Care University Hospital in the North West Bank: A Descriptive Study

Background: The prevalence of multidrug-resistant organisms (MDROs) in acute healthcare settings is increasing worldwide. Active screening for MDROs carriers on admission permits the prompt implementation of the appropriate precautions to decrease the probability of cross transmission to other inpatients. Objective: To report the spectrum of bacterial nasal, axilla, and perianal colonization among in patients at Najah National University Hospital (NNUH) during 2018. Methods: A retrospective observational study was performed at NNUH, a tertiary-care referral university hospital in Nablus, north of Palestine, that includes medical and surgical ICUs for both adults and children from January to August 2018. Nasal, axilla, and perianal swabs were collected within the first 24 hours of admission according to hospital policy. Patients who were referred from another hospital, who were admitted to a hospital for at least 2 nights during the previous 8 months, and who are known to have an MDROs in the past were included. Swab samples were processed for isolation and identification of these multidrug-resistant strains. Transmission-based precautions were implemented if positive results were reported (ie, contact isolation) and decolonization regimens were applied according to the CDC recommendations (muporocin ointment for nasal MRSA, daily bathing with chlorhexidine 2% soap for the rest). A daily isolation list was circulated among bed managers and senior nurses and head of departments for appropriate management of beds and reallocation of patients. The antibiotic susceptibility pattern was assessed using the disc-diffusion method on Mueller–Hinton agar and a Vitek-2 system. Results: During the period of the study, 1,425 nasal swabs, 1,245 axilla swabs, and 300 perianal swabs were collected according to the inclusion criteria. Positive results were reportedin 7%, 4%, and 44% for nasal, axilla, and perianal specimens, respectively. Regarding the distribution of bacterial colonization in the nasal swab, 73% were MRSA; for the axial, 29% were Pseudomonas; and from the perianal swab, the most prevalent pathogen was ESBL (56%) (Figs. 1–3). A discrepancy between the number of nasal or axilla and perianal swabs was observed, which was mainly due to the refusal of many patients to have the sample collected by the nurse. Conclusions: Colonization of the skin and mucous membranes of inpatients with MDROs is considered a risk factor for developing future infections. Therefore, active screening for those pathogens is critical for infection prevention and control programs and patient safety in acute-care settings.Funding: NoneDisclosures: None

SARS-CoV-2 detection in setting of viral swabs scarcity: Are MRSA swabs and viral swabs equivalent?

The global pandemic of Severe Acute Respiratory Syndrome-Related Coronavirus 2 (SARS-CoV2) has resulted in unprecedented challenges for healthcare systems. One barrier to widespread testing has been a paucity of traditional respiratory viral swab collection kits relative to the demand. Whether other sample collection kits, such as widely available MRSA nasal swabs can be used to detect SARS-CoV-2 is unknown. We compared simultaneous nasal MRSA swabs (COPAN ESwabs ® 480C flocked nasal swab in 1mL of liquid Amies medium) and virals wabs (BD H192(07) flexible mini-tip flocked nasopharyngeal swabs in 3mL Universal Transport Medium) for SARS-CoV-2 PCR testing using Simplexa COVID-19 Direct assay on patients over a 4-day period. When the results were discordant, the viral swab sample was run again on the Cepheid Xpert Xpress ® SARS-CoV-2 assay. Of the 81 included samples, there were 19 positives and 62 negatives in viral media and 18 positives and 63 negative in the MRSA swabs. Amongst all included samples, there was concordance between the COPAN ESwabs ® 480C and the viral swabs in 78 (96.3%). We found a high rate of concordance in test results between COPAN ESwabs ® 480C in Amies solution and BD H192(07) nasopharyngeal swabs in in 3 mL of Universal Viral Transport medium viral media. Clinicians and laboratories should feel better informed and assured using COPAN ESwabs ® 480C to help in the diagnosis of COVID-19.

Prolonged carriage of (livestock-associated) MRSA in individuals without professional livestock contact.

To investigate prolonged carriage of MRSA in adults from the general population living in a livestock-dense area, using WGS. A cross-sectional study during 2014-15 among 2492 adults without professional livestock contact identified 14 (0.6%) nasal MRSA carriers, 10 of which carried livestock-associated (LA)-MRSA of multiple-locus variable-number tandem repeat analysis (MLVA) complex (MC) 398. Two years later, 12 MRSA-positive and 88 MRSA-negative participants provided a second nasal swab and filled in a short questionnaire. Isolates from persons who were MRSA positive at both timepoints were compared using MLVA and isolates with the same MLVA type were sequenced. The WGS data were used for core-genome MLST (cgMLST) and resistome analysis, including sequenced isolates from the national MRSA surveillance. All MRSA-negative persons tested negative again, while 6 of the 12 initially MRSA-positive persons tested positive again. MLVA revealed that isolate pairs from five individuals had the same MLVA type, of which three were LA-MRSA. cgMLST showed that the distance between these isolate pairs ranged between 3 and 13 genes, while the minimum distance to unrelated isolates from the national MRSA surveillance was 38 genes. Moreover, the resistome present in the five isolate pairs was identical within each pair. None of the prolonged carriers was hospitalized during the 3 months before the sampling moment and none of them with LA-MRSA had contact with livestock in this period. Prolonged carriage of MRSA, including LA-MRSA, can be demonstrated after more than 30 months in persons without professional livestock contact.

Phenotypic and Molecular Screening of Nasal S. aureus from Adult Hospitalized Patients for Methicillin- and Vancomycin-resistance.

Nasal carriers of Staphylococcus aureus are common and play an important role in the transmission of infections. The aim of this study is a phenotypic and molecular investigation of nasal methicillin- and vancomycin-resistant S. aureus in hospitalized patients. 202 nasal swabs were collected from patients at Prince Hamzah Hospital, Jordan, through 2016-2017. Swabs were processed according to standard microbiological procedures to isolate Staphylococci. Antibiotic susceptibility testing was performed using disk diffusion, E-test, microdilution and Vitek 2. Methicillin resistance was confirmed by testing for the mecA gene, while vancomycin resistance was screened by testing for the vanA and vanB genes. The mean age of participants was 50.17±18.18 years and 59.4% were females. Nasal Staphylococci was isolated in 64/202 (31.7%), S. aureus was isolated from 33 samples (16.3%), MRSA was isolated from 13 samples (6.4%) and constitutive Macrolide-lincosamidestreptogramin B (MLSB) was isolated from 12 samples (5.9%). All MRSA isolates harbored the mecA gene. All isolates were sensitive to vancomycin using E-test and the microdilution test and were negative for the vanA and vanB genes. The highest resistance rate was observed for benzylpenicillin (>90%), while the lowest resistance rate was for tobramycin (<5%) among all isolates. Nasal Staphylococci, S. aureus and MRSA colonization significantly correlate with increased number of family members and previous hospitalization (P<0.05), while nasal S. aureus significantly correlates with a history of skin infection (P=0.003). Nasal colonization by mecA-mediated MRSA is common among hospitalized patients, while vanA- and vanB-mediated vancomycin resistance was not detected in any nasal isolates.

2003. Vancomycin Discontinuation Is Supported by-negative Nasal Methicillin-Resistant Staphylococcus aureus (MRSA) in Patients with Pneumonia

BackgroundA negative nasal MRSA PCR test has a 98–99.6% sensitivity in confirming that MRSA is not the causative organism associated with pneumonia in hospitalized patients. Evidence supporting the clinical utility of nasal MRSA PCR testing in the Veteran patient population is limited, with no identified publications to date. The purpose of this project was to share outcomes associated with implementation of nasal MRSA PCR testing in the Veteran population to guide duration of vancomycin therapy.MethodsThis retrospective cohort quality initiative compared treatment of pneumonia that included vancomycin during a pre-Antimicrobial Stewardship Program (ASP) intervention phase (August 2013–February 2014) to an active ASP intervention phase (August 2017–March 2019). ASP intervention consisted of utilization of a negative nasal MRSA PCR as a rapid diagnostic test to support discontinuation of vancomycin prior to microbiologic culture results. Retrospective chart review evaluated vancomycin days of therapy (DOT), hospital length-of-stay (LOS), 30-day hospital readmission, and 30-day mortality. Patients admitted to the intensive care unit during the identified hospitalization were excluded.ResultsThe average vancomycin DOT significantly declined by 1.08 days when comparing the pre-ASP intervention phase (N = 25) to the ASP-intervention phase (N = 47) (3.6 vs. 2.52 days, respectively; P = 0.0088). Mean hospital LOS decreased by 1.5 days (6.04 vs. 4.54 days, respectively, P = 0.0885). There was no significant difference in 30-day hospital readmission rate (12% vs. 8.5%) or 30-day mortality rate (12% vs. 10%).ConclusionVancomycin DOT was reduced by 30% (1.08 days) and hospital LOS was reduced by 24.8% (1.5 days) in patients with pneumonia during a Vet. Affairs medical center’s utilization of negative nasal MRSA PCR testing to support vancomycin discontinuation. This project highlights the role of nasal MRSA PCR as a rapid diagnostic test to aid in diminishing empiric vancomycin usage and its associated toxicities. Disclosures All authors: No reported disclosures.

1458. A Single-Center Quasi-Experimental Study to Evaluate the Impact of Utilizing Rapid Diagnostic Technology to Detect Methicillin-Resistant Staphylococcus aureus in Respiratory Culture Samples

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) is a relevant pathogen for patients with pneumonia in the presence of certain risk factors. Empiric broad-spectrum antimicrobial therapy, including anti-MRSA therapy, is frequently initiated in patients hospitalized with pneumonia. The low yield of respiratory cultures makes antimicrobial de-escalation difficult, potentially leading to extended durations of anti-MRSA therapy and increasing risk for significant drug-related adverse effects. A polymerase chain reaction (PCR) test that was previously utilized for nasal MRSA screening was internally validated to identify the presence of MRSA in respiratory specimens within 2 hours of sample collection. The primary objective of this study was to determine the effect of this respiratory PCR test on duration of anti-MRSA therapy in nonintensive care unit (ICU) patients hospitalized with pneumonia.MethodsImplementation of the PCR test in non-ICU units occurred December 1, 2017. During the post-intervention (INT) period (December 1, 2017–March 31, 2018), PCR results were evaluated daily by antimicrobial stewardship and decentralized staff pharmacists for therapy de-escalation opportunities, with recommendations communicated to prescribers. The pre-INT group (December 1, 2016–March 31, 2017) consisted of non-ICU patients hospitalized with pneumonia who received anti-MRSA therapy for at least 48 hours, or who qualified for anti-MRSA therapy per institutional guidelines.ResultsA total of 169 patients were evaluated; 109 in the post-INT group and 60 in the pre-INT group. Anti-MRSA therapy was administered to 74 patients (68%) in the post-INT group, compared with 56 patients (93%) in the pre-INT group. The median duration of anti-MRSA therapy post-INT was 23.5 hours, which was significantly shorter than the pre-INT duration of 55.5 hours (P < 0.0001). The post-INT group also had significantly less vancomycin-induced nephrotoxicity (P < 0.0383) and a shorter time to targeted therapy (P < 0.0001). No difference in 30-day all-cause mortality was observed (P < 0.1338).ConclusionUtilization of a PCR test to detect MRSA in respiratory specimens decreased duration of anti-MRSA therapy in non-ICU patients hospitalized with pneumonia.Disclosures All authors: No reported disclosures.

High prevalence of mupirocin resistance in methicillin resistant staphylococci and its clinical significance

Background: With the increasing pressure to prevent MRSA infections, it is possible that there will be increased use of Mupirocin for nasal decolonization of MRSA. Mupirocin is bacteriostatic at low concentration near the MIC for staphylococcus aureus but it is bactericidal at concentrations achieved by topical administration (20,000ug/ml) with the 2% formulation. Earlier reported High level Mupirocin resistance strain is associated with decolonization failure. The present study was carried out to determine the rates of high level and low level Mupirocin resistance (MuH and MuL) in methicillin resistant Staphylococcus aureus and methicillin resistant coagulase negative staphylococci. Materials and methods: A prospective study was carried out on 104 non-duplicate Staphylococcal isolates from various clinical specimens were tested for Mupirocin resistance using 5µg and 200µg discs. Detection of Mupirocin resistance was done by the disk diffusion method using 5 μg and 200 μg Mupirocin disks to determine low- and high-level resistance, respectively. Results: Mupirocin resistance was 7.8%, and 4.6% in MRSA and 40% and 20% in MR-CONS for 5 µg and 200 µg disc respectively. Conclusion: Institutions that are considering the implementation of widespread Mupirocin use should consider these resistance issues and develop strategies to monitor the impact of Mupirocin use. Perioperative prophylaxis with nasal mupirocin therapy (PPNMT) can reduce the incidence of MRSA SSls after orthopaedic surgery, probably by reducing nasal MRSA carriage in the endemic setting, without selecting for mupirocin resistance.

183 Spatiotemporal Patterns and Social Determinants of Community-Associated Methicillin Resistant Staphylococcus aureus Skin and Soft Tissue Infections Among Emergency Department Patients in North Central Florida

To investigate spatial and social demographic patterns of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) skin or soft tissue infection (SSTI) in patients presenting to the emergency department in North Central Florida. From August 2015-January 2017, pediatric and adult patients presenting to UF Health Shands Emergency Department in Gainesville, FL with an acute SSTI were prospectively enrolled in cross-sectional study. Both nasal and SSTI site specimens were collected and cultured for spa-typing. Geographic, social, medical, and other patient-level epidemiological data was collected. Department of Defense rural-urban classification system and 2010 Census data was used for spatial and geographic analysis. Multivariate analyses were conducted to test associations of determinants and microbiological result. 171 subjects were included, spanning 24 counties and 69 zip codes based on self-reported home residence. 121 (75.4%) of subjects enrolled reported living in rural zip codes. 50 (29.2%) subjects had MRSA positive wound cultures and 24 (14%) had MRSA positive nasal cultures. MRSA positive wound culture was associated with recent exposure to livestock (p=0.006) while nasal colonization of MRSA was associated with current alcohol consumption (p=0.041), current history of smoking (p=0.003), and antimicrobial soap use (p=0.024). Nasal colonization of MRSA or MSSA was a significant predictor of positive MRSA wound cultures (p=<0.001) and positive MSSA wound cultures (p=0.004), respectively. Subjects residing in rural zip codes were 2.6 (CI:1.07-6.33, p=0.033) times more likely to have MRSA positive wound cultures. There was no association between zip code classification and nasal MRSA colonization. The geographic distribution of CA-MRSA is not uniform and has a higher prevalence in less populated more rural areas, potentially highlighting a zoonotic association in CA-MRSA transmission. Although previous studies have also shown the association of nasal MRSA colonization and MRSA positive wound culture, this study suggests an association of nasal MSSA colonization and MSSA positive wound cultures which has not been previously well recognized. Associations with nasal MRSA colonization and social demographics provide insight to possible preventative therapies to reduce CA-MRSA infections. While the effectiveness of antimicrobial soaps are disputed and regulated, the possible promotion of nasal MRSA colonization due to use requires investigation. Genetic spa-typing analysis will provide further insight regarding spatiotemporal transmission across communities.