Faculty Bibliography

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.

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)

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: A first-generation cephalosporin is the recommended antibiotic prophylaxis for implants. However, this standard does not address the increasing prevalence and virulence of gram-negative pathogens infecting patients. We found that gram-negative bacilli caused 30% of our surgical site infections (SSIs) following hip procedures, whereas only 10% of knee SSIs were caused by gram-negative bacilli. To address this, we instituted Expanded Gram-Negative Antimicrobial Prophylaxis (EGNAP) for our hip arthroplasty patients. The purpose of this study is to measure the effect of EGNAP on the SSI rates following primary total hip arthroplasty. METHODS: The study consisted of 10,084 total patients. Before July 2012, all patients were administered 1 g of cefazolin. After July 2012, our protocol was adjusted by adding the EGNAP with either gentamicin or aztreonam to hip patients (group 1) and not to the knee arthroplasty patients (group 2). RESULTS: Group 1 consisted of the 5389 primary hip arthroplasty patients. Of these patients, 4122 (before July 2012) did not receive weight-based high-dose gentamicin and 1267 (after July 2012) did. Before the introduction of EGNAP, group 1 SSI rate was 1.19% (49/4122). After July 2012 when EGNAP was added, the overall group 1 SSI rate decreased to 0.55% (7/1267) (P = .05). During the study period, there was not a significant difference in SSI rate of knee arthroplasty (group 2): 1.08% vs 1.02% (P = .999). CONCLUSIONS: The addition of EGNAP for hip arthroplasty is a safe and effective method to decrease SSIs. LEVEL OF EVIDENCE: III. Case-control study.

BACKGROUND: Recent studies described an increase in acute kidney injury when high dose gentamicin was included in perioperative prophylaxis for orthopedic surgeries. To this effect, we compared the rate of nephrotoxicity for selected orthopedic surgeries where gentamicin was included (Gentamicin Group) to those where it was not included (Control Group) for perioperative prophylaxis and evaluated risk factors for nephrotoxicity. METHODS: Spine, hip and knee surgeries performed between April 2011 and December 2013 were reviewed retrospectively. Gentamicin was given to eligible patients based on age, weight and Creatinine Clearance. Nephrotoxicity was assessed using Risk, Injury, Failure, Loss, End-stage kidney disease (RIFLE) criteria. RESULTS: Among selected surgeries (N = 1590 in Gentamicin Group: hip = 926, spine = 600, knee = 64; N = 2587 in CONTROL GROUP: hip = 980, spine = 902, knee = 705), patients' body weight, serum creatinine, comorbidities and surgery duration were similar in Gentamicin Group and CONTROL GROUP. Gentamicin median dose was 4.5 mg/kg of dosing weight. Nephrotoxicity rate was 2.5% in Gentamicin Group and 1.8% in CONTROL GROUP, p = 0.17. Most cases of nephrotoxicity were Risk category by RIFLE criteria (67% in Gentamicin Group and 72% in CONTROL GROUP, p = 0.49). In logistic regression, risk factors for nephrotoxicity were hospital stay >1 day prior to surgery (odds ratio = 8.1; 95% confidence interval = 2.25-28.97, p = 0.001), knee or hip surgery (odds ratio = 4.7; 95% confidence interval = 2.9-9.48, p = 0.0005) and diabetes (odds ratio = 1.95; 95% confidence interval = 1.13-3.35, p = 0.016). Receipt of gentamicin was not an independent predictor of nephrotoxicity (odds ratio = 1.5; 95% confidence interval = 0.97-2.35, p = 0.07). CONCLUSION: In this cohort, rate of nephrotoxicity was similar between Gentamicin Group and Control Group. Single high dose gentamicin is a safe and acceptable option for perioperative prophylaxis in eligible patients undergoing orthopedic surgeries.

BACKGROUND: Central venous catheters are crucial devices in the care of hospitalized children, both in and out of critical care units, but the concomitant risk of central line-associated bloodstream infection (CLABSI) affects 15,000 Americans annually. In 2012, CLABSI rates varied among units from 6.8/1,000 to 1.0/1,000 in a 109-bed children's service within NYU Langone Medical Center (NYULMC; New York City), a 1,069-bed tertiary care academic medical center. In response to variation in central line-related practices and infection prevention rates, a CLABSI Prevention Core Team began an effort to standardize central venous catheter (CVC) care across all pediatric units (ICU and non-ICU). Momentum in this quality improvement (QI) work was interrupted when Superstorm Sandy shuttered the flagship hospital, but the relatively decreased clinical load provided a "downtime" opportunity to address CLABSI prevention. METHODS: The first phase of the collaborative effort, Booster 1, Planning/Initial Phase: Development of a Pediatric Central Venous Catheter Working Group, was followed by Booster 2, Maintenance/Sustaining Phase: Transitioning for Sustainability and Adopting Model for Improvement. RESULTS: Data in the subsequent 21 months after the temporary closure of the facility (January 2013-September 2014) showed an increase in maintenance bundle reliability. The inpatient CLABSI rate for patients < 18 years decreased from an annual rate of 2.7/1,000 line days (2012) to 0.6/1,000 line days (2013) to 0.5/1,000 line days as of August 2014. There was a decrease in pediatric CLABSI events and no significant change in line days. CONCLUSIONS: Key elements contributing to initial success with evolving QI capacity and resources were likely multi-factorial, including staff and leadership engagement, culture change, consistent guidelines, and accountability by individuals and by our multidisciplinary core team.