Faculty Bibliography

AIMS/OBJECTIVE:non-anterior (NA) surgical approaches on prosthetic joint infection (PJI), and examined the impact of new perioperative protocols on PJI rates following all surgical approaches at a single institution. PATIENTS AND METHODS/METHODS:(13.3 to 57.6, sd 6.1), respectively. Infection rates were calculated yearly for the DA and NA approach groups. Covariates were assessed and used in multivariate analysis to calculate adjusted odds ratios (ORs) for risk of development of PJI with DA compared with NA approaches. In order to determine the effect of adopting a set of infection prevention protocols on PJI, we calculated ORs for PJI comparing patients undergoing THA for two distinct time periods: 2013 to 2014 and 2015 to 2016. These periods corresponded to before and after we implemented a set of perioperative infection protocols. RESULTS:There were 1985 patients in the DA group and 4101 patients in the NA group. The overall rate of PJI at our institution during the study period was 0.82% (50/6086) and decreased from 0.96% (12/1245) in 2013 to 0.53% (10/1870) in 2016. There were 24 deep PJIs in the DA group (1.22%) and 26 deep PJIs in the NA group (0.63%; p = 0.023). After multivariate analysis, the DA approach was 2.2 times more likely to result in PJI than the NA approach (OR 2.2 (95% confidence interval 1.1 to 3.9); p = 0.006) for the overall study period. CONCLUSION/CONCLUSIONS:2019;101-B(6 Supple B):2-8.

The past two decades have witnessed an alarming expansion of staphylococcal disease caused by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). The factors underlying the epidemic expansion of CA-MRSA lineages such as USA300, the predominant CA-MRSA clone in the United States, are largely unknown. Previously described virulence and antimicrobial resistance genes that promote the dissemination of CA-MRSA are carried by mobile genetic elements, including phages and plasmids. Here, we used high-resolution genomics and experimental infections to characterize the evolution of a USA300 variant plaguing a patient population at increased risk of infection to understand the mechanisms underlying the emergence of genetic elements that facilitate clonal spread of the pathogen. Genetic analyses provided conclusive evidence that fitness (manifest as emergence of a dominant clone) changed coincidently with the stepwise emergence of (i) a unique prophage and mutation of the regulator of the pyrimidine nucleotide biosynthetic operon that promoted abscess formation and colonization, respectively, thereby priming the clone for success; and (ii) a unique plasmid that conferred resistance to two topical microbiocides, mupirocin and chlorhexidine, frequently used for decolonization and infection prevention. The resistance plasmid evolved through successive incorporation of DNA elements from non-S. aureus spp. into an indigenous cryptic plasmid, suggesting a mechanism for interspecies genetic exchange that promotes antimicrobial resistance. Collectively, the data suggest that clonal spread in a vulnerable population resulted from extensive clinical intervention and intense selection pressure toward a pathogen lifestyle that involved the evolution of consequential mutations and mobile genetic elements.

Background. Catheter-associated urinary tract infections (CAUTI) negatively impact patient morbidity, mortality and insurance reimbursement rates in acute care hospitals. Since CAUTIs are solely defined by the National Health and Safety Network (NHSN), not by clinical definition or urinalysis (UA) result, eliminating unnecessary urine cultures will improve the accuracy of reportable CAUTI rates. Negative UA can accurately detect false-positive (FP) CAUTIs in patients with 100% negative predictive value. Methods. We conducted a retrospective analysis of 2017 CAUTIs reported from two acute care hospitals (A and B) to determine the effectiveness of a UA screening protocol and the distribution of FPs. Hospital B implemented a UA screening protocol requiring a UA prior to urine culture. Hospital A relied solely on microbiology cultures. FPs were identified by a negative UA result, the absence of bacteria, performed on the same or prior day to the urine culture that resulted in a CAUTI. Results. Our analysis showed that 13 (34%) of the 38 reported CAUTIs with an associated UA result at hospital A were FPs. Patients with a UC line duration >7 days had a CAUTI FP rate of 62% compared with 27% of those with a line duration between 3 and 7 days (Figure 1) (OR 4.6, CI: 0.9, 23.7, P = 0.09). Hospital A (no screening protocol) was 37.4 times more likely to have a FP CAUTI compared with hospital B (UA screening protocol) (CI: 2.1, 660.6; P < 0.0004). Conclusion. A positive culture with a negative UA is indicative of asymptomatic colonization, not true infection. Preventing FP CAUTIs would result in a 34% reduction in CAUTI rates at hospital A, placing the hospital in a better reimbursement benchmark (Figure 2). Interventions include: (1) A best practice alert in the patient's electronic medical record that can be used to notify the providers to re-evaluate patients with UCs in place >= 5 days, (2) A screening protocol that requires a UA order prior to/during specimen collection and prevents processing of urine cultures with a negative UA. In patients with UCs, a protocol should be implemented to reduce FP CAUTIs to better understand the true epidemiology of CAUTIs in hospitals and increase reporting accuracy. (Figure Presented)

Background. The multiplex polymerase chain reaction respiratory pathogen panel (RPP) is used frequently in emergency departments (EDs) for the rapid identification of viruses and atypical bacteria of the respiratory tract. Its clinical value is unclear, as numerous studies have demonstrated that its use has a limited impact on antibiotic prescribing. We aimed to describe the relationship between RPP results and antibiotic prescribing rates for ED patients in our large academic medical center. Methods. We retrospectively analyzed the charts of 1,061 patients aged 18-90 who were treated and released from two EDs from January 1, 2015 to January 31, 2018 and underwent RPP testing. Patients with evidence of bacterial infection were excluded based on RPP detection of atypical bacteria and microbiological analysis of blood, urine, wound, and sputum specimens. The results of the RPP and the rates of subsequent respiratory pathogen-directed antibiotic prescribing (including ED and outpatient pharmacy orders) were compared. Results. Antibiotic prescription rates were 21.5% in patients who tested negative for any respiratory virus, compared with 14.5% in patients who tested positive (OR 0.70, P < 0.01). When positive RPPs were subdivided based on virus type (influenza and non-influenza) and compared with negative RPPs, only influenza-detection was associated with a significant reduction in antibiotic prescriptions (Table 1). Conclusion. In our study population, the presence of a respiratory virus detected by the RPP was correlated with a significant decrease in antibiotic prescribing. This effect was largely driven by influenza detection. This demonstrates that at our institution, the RPP may have a role in reducing unnecessary antibiotic utilization, but providers need further guidance in the interpretation of non-influenza respiratory virus positivity. (Table Presented)

BACKGROUND: The timely identification of a cluster is a critical requirement for infection prevention and control (IPC) departments because these events may represent transmission of pathogens within the health care setting. Given the issues with manual review of hospital infections, a surveillance system to detect clusters in health care settings must use automated data capture, validated statistical methods, and include all significant pathogens, antimicrobial susceptibility patterns, patient care locations, and health care teams. METHODS: We describe the use of SaTScan statistical software to identify clusters, WHONET software to manage microbiology laboratory data, and electronic health record data to create a comprehensive outbreak detection system in our hospital. We also evaluated the system using the Centers for Disease Control and Prevention's guidelines. RESULTS: During an 8-month surveillance time period, 168 clusters were detected, 45 of which met criteria for investigation, and 6 were considered transmission events. The system was felt to be flexible, timely, accepted by the department and hospital, useful, and sensitive, but it required significant resources and has a low positive predictive value. CONCLUSIONS: WHONET-SaTScan is a useful addition to a robust IPC program. Although the resources required were significant, this prospective, real-time cluster detection surveillance system represents an improvement over historical methods. We detected several episodes of transmission which would have eluded us previously, and allowed us to focus infection prevention efforts and improve patient safety.

Background. Antibiotic (ABX) use and outcome measures (rate of HO-CDI, local antimicrobial resistance) are recommended ASP metrics. These metrics can be used for internal benchmarking to assess ASP performance within an institution over time. Methods. An adult ASP at our 750-bed academic medical center was implemented in 2008. ASP interventions include prospective audit and feedback, prior authorization with fuoroquinolone (FLQ) restriction as an ASP target and implementation of facility-specifc guidelines for common infections. Newer ASP initiatives were Cepheid/Xpert for blood cultures with Gram-positive cocci in pairs and clusters with daily real-time ASP interventions (11/2014), oral vancomycin secondary prophylaxis for patients with prior CDI (4/2014) and optimization of beta-lactam (BL) dosing (pip-eracillin-tazobactam [PTZ] extended infusion hospital-wide 4/2013; cefepime [CEF] 4/2015 and meropenem 7/2015 protocols). ABX use is measured in days of therapy per 1000 patient-days (DOT/1000 PD) and length of therapy/admission when ABX were administered (LOT/ADM). NHSN defnition is used for HO-CDI. For resistance trends the first unique isolate/patient/year regardless of source or susceptibility profle was included. Statistical analysis of trends during 8-years period 2009-2016 was performed by Poisson (SAS). Results. Major shifs in ABX use include decrease in FLQ use (-17%, P < 0.01) with compensatory increase in cefriaxone (CTX, +12%, P < 0.01), antipseudomonal BL (+3%, P < 0.01) and no change in carbapenem (+0.6%, P=0.5) as well as an increase in nafcillin and oxacillin (+7%, P < 0.01) use. There was a decrease in aggregate LOT/ADM (-4%, P < 0.01) with no change in DOT/1000 PD. We observed a decrease in HO-CDI rate (-17%, P < 0.01). Major resistance trends include reduction in Enterobacteriaceae spp. and Pseudomonas aeruginosa isolates nonsusceptible (NS) to FLQ (-4%, P < 0.01;-10%, P < 0.01, respectively) with increase in Enterobacteriaceae spp. NS to cefriaxone, (+3%, P < 0.01). A decrease in P. aeruginosa NS to PTZ (-11%, P < 0.01) and no change for CEF was reported. There was no Difference in Enterobacteriaceae spp. NS to PTZ or CEF. Conclusion. Overall, reported trends aligned with ASP initiatives. Increased CTX NS is of concern and warrants an ASP-led strategy to decrease CTX use

A global outbreak of invasive Mycobacterium chimaera infections after cardiac surgery has recently been linked to bioaerosols from contaminated heater-cooler units. The majority of cases have occurred after valvular surgery or aortic graft surgery and nearly half have resulted in death. To date, infections in patients with left ventricular assist devices (LVADs) have not been characterized in the literature. We report two cases of device-associated M. chimaera infection in patients with continuous-flow LVADs and describe challenges related to diagnosis and management in this population.

INTRODUCTION: Staphylococcus aureus (S aureus) decolonization regimens are being used to mitigate the risk of surgical site infection (SSI). However, their efficacy is controversial, with mixed results reported in the literature. METHODS: Before undergoing primary total knee arthroplasty (TKA), total hip arthroplasty (THA), or spinal fusion, 13,828 consecutive patients were screened for nasal S aureus and underwent a preoperative decolonization regimen. Infection rates of colonized and noncolonized patients were compared using unadjusted logistic regression. An adjusted regression analysis was performed to determine independent risk factors for SSI. RESULTS: The rate of SSI in colonized patients was 4.35% compared with only 2.39% in noncolonized patients. In our TKA cohort, unadjusted logistic regression identified S aureus colonization to be a significant risk factor for SSI (odds ratio [OR], 2.9; P < 0.001). After controlling for other potential confounders including age, body mass index, tobacco use, and American Society of Anesthesiologists score, an SSI was 3.8 times more likely to develop in patients colonized with S aureus (OR, 3.8; P = 0.0025). The THA and spine colonized patients trended toward higher risk in both unadjusted and adjusted models; however, the results were not statistically significant. DISCUSSION: The results of our study suggest that decolonization may not be fully protective against SSI. The risk of infection after decolonization is not lowered to the baseline of a noncolonized patient. LEVEL OF EVIDENCE: Level IV.

Background. We have recently observed an increase in community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections among pediatric patients from Brooklyn hospitalized at a university-based teaching hospital in New York City. We performed a prospective study to determine the colonization prevalence of CA-MRSA among hospital admission, genome sequence strains causing infection and identified risk factors associated with CA-MRSA carriage in this population. Methods. Colonization data were obtained from routine infection control screening upon admission to the general pediatric and intensive care units. We used a questionnaire to identify risk factors for MRSA transmission. Additionally, single patient isolates of CA-MRSA were collected from the clinical microbiology laboratory. Medical record information was used to ascertain patient infection or colonization and to confirm community onset. Children from high-risk communities were identified via zip codes. Figure. Phylogenetic tree of clinical MRSA USA300 isolates from children living in high-risk zip codes (red), adult and pediatric patients at NYU Tisch Hospital (Blue), and USA300 Strains from around the United States (Green; Pfizer). Results. Children from the high-risk zip codes were 3 times as likely to be colonized with MRSA (9% versus 3% [p = 0.04]). No difference in methicillin-susceptible S. aureus colonization prevalence was observed between children from high-risk and low-risk communities. Likewise, the MRSA infection rate per 1000 patient days was 36 for children from high-risk zip codes, and 3.9 in children from low-risk zip codes (p < 0.0001). All isolates from patients in high risk zip codes analyzed to date belong to genotype USA300, the predominant CA-MRSA clone in the United States. Phylogenetic analyses suggest that these strains arose from expansion of an USA300 CAMRSA subclone. Potential risk factors for MRSA infection are being explored in conjunction with public health and community leaders. Conclusion. We identified a cluster of CA-MRSA strain USA300 among pediatric patients in a high risk Brooklyn community. Additional genomic comparisons and epidemiological data will be used to inform interventions and interrupt transmission. (Figure Presented)