Faculty Bibliography

Polymyxins are reserved for salvage therapy of infections caused by carbapenem-resistant Klebsiella pneumoniae (CRKP). Though synergy has been demonstrated for the combination of polymyxins with carbapenems or tigecycline, in vitro synergy tests are nonstandardized, and the clinical effect of synergy remains unclear. This study describes outcomes for patients with CRKP infections who were treated with polymyxin B monotherapy. We retrospectively reviewed the medical records of patients with CRKP infections who received polymyxin B monotherapy from 2007 to 2011. Clinical, microbiology, and antimicrobial treatment data were collected. Risk factors for treatment failure were identified by logistic regression. Forty patients were included in the analysis. Twenty-nine of 40 (73%) patients achieved clinical cure as defined by clinician-documented improvement in signs and symptoms of infections, and 17/32 (53%) patients with follow-up culture data achieved microbiological cure. End-of-treatment mortality was 10%, and 30-day mortality was 28%. In a multivariate analysis, baseline renal insufficiency was associated with a 6.0-fold increase in clinical failure after adjusting for septic shock (odds ratio [OR] = 6.0; 95% confidence interval [CI] = 1.22 to 29.59). Breakthrough infections with organisms intrinsically resistant to polymyxins occurred in 3 patients during the treatment. Eighteen of 40 (45%) patients developed a new CRKP infection a median of 23 days after initial polymyxin B treatment, and 3 of these 18 infections were polymyxin resistant. The clinical cure rate achieved in this retrospective study was 73% of patients with CRKP infections treated with polymyxin B monotherapy. Baseline renal insufficiency was a risk factor for treatment failure after adjusting for septic shock. Breakthrough infections with organisms intrinsically resistant to polymyxin B and development of resistance to polymyxin B in subsequent CRKP isolates are of concern.

Objective. To describe the epidemiology of carbapenem-resistant Enterobacteriaceae (CRE) carriage and acquisition among hospitalized patients in an area of CRE endemicity. Design. Cohort study with a nested case-control study. Setting. Two acute care, academic hospitals in New York City. Participants. All patients admitted to 7 study units, including intensive care, medical-surgical, and acute rehabilitation units. Method. Perianal samples were collected from patients at admission and weekly thereafter to detect asymptomatic gastrointestinal carriage of CRE. A nested case-control study was performed to identify factors associated with CRE acquisition. Case patients were those who acquired CRE during a single hospitalization. Control subjects had no microbiologic evidence of CRE and at least 1 negative surveillance sample. Clinical data were abstracted from the medical record. Results. The prevalence of CRE in the study population was 5.4% (306 of 5,676 patients), and 104 patients met the case definition of acquisition during a single hospital stay. Mechanical ventilation (odds ratio [OR], 11.5), pulmonary disease (OR, 5.2), days of antibiotic therapy (OR, 1.04), and CRE colonization pressure (OR, 1.15) were independently associated with CRE acquisition. Pulsed-field gel electrophoresis analysis identified 87% of tested Klebsiella pneumoniae isolates as sharing related patterns (greater than 78% similarity), which suggests clonal transmission within and between the study hospitals. Conclusions. Critical illness and underlying medical conditions, CRE colonization pressure, and antimicrobial exposure are important risk factors for CRE acquisition. Adherence to infection control practices and antimicrobial stewardship appear to be critical components of a CRE control program.

BACKGROUND: Hospital-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a source of morbidity and mortality. S. aureus is the most common pathogen in prosthetic joint infections and the incidence of MRSA is increasing. QUESTIONS/PURPOSES: The purposes of this study were (1) to determine the MRSA prevalence density rate at a specialty orthopaedic hospital before and after implementation of a screening and decolonization protocol, (2) to compare our prevalence density with that of an affiliated university hospital to control for changes in MRSA prevalence density that might have been independent of the decolonization protocol, and (3) to measure the admission prevalence density rate of MRSA in an elective orthopaedic surgery population and the compliance rate of 26 patients with the protocol. METHODS: In October 2008, we implemented a MRSA screening and decolonization protocol for patients undergoing elective orthopaedic surgery. Nasal swabs were used for screening and mupirocin nasal ointment and chlorhexidine skin antisepsis where prescribed for decolonization to all patients. At the surgical visit, compliance was measured and the patients who were MRSA positive received vancomycin for antibiotic prophylaxis. Institution wide surveillance for multidrug-resistant organisms, including MRSA provided a comparison of the change in MRSA burden at the orthopaedic hospital versus the university hospital. RESULTS: Before implementation of the preoperative staphylococcal decolonization protocol there were 79 MRSA-positive cultures in 64,327 patient-days for a prevalence density rate of 1.23 per 1000 patient-days. After protocol implementation, 53 MRSA-positive cultures were identified in 63,860 patient-days for a rate of 0.83 per 1000 patient-days. Before the protocol, the MRSA prevalence density at the specialty hospital was similar to that of the university hospital; after implementation of the protocol, the prevalence density at the specialty hospital was 33% lower than that of the university hospital. The MRSA admission prevalence was 3.02%. The compliance rate was greater than 95%. CONCLUSIONS: Implementation of a staphylococcal decolonization protocol at a single specialty orthopaedic hospital decreased the prevalence density of MRSA.

The aim of this retrospective study was to identify risk factors for hospital-acquired Clostridium difficile infection (HA-CDI) in orthopaedic patients. Thirty-two HA-CDI cases were each matched with two controls. Incidence rate was 0.33 cases per 1000 patient-days. Univariate analyses showed that surgery >24 h after admission, antibiotics for treatment, and proton pump inhibitors were associated with HA-CDI. Multivariate analyses revealed that surgery >24 h after admission was associated with HA-CDI. Patients hospitalized before surgery had a greater risk of HA-CDI, suggesting opportunities to reduce environmental exposure to C. difficile by timelier preoperative medical optimization in the outpatient setting.

In May 2001, The New York City Department of Health and Mental Hygiene was informed of a cluster of 4 patients treated at an outpatient gastroenterology center who developed acute hepatitis C virus infection. An investigation identified a total of 12 clinic-associated hepatitis C virus transmissions and the outbreak and was traced to unsafe handling of multidose anesthetic vials and possible re-use of contaminated needles. This report typifies the types of outbreaks that continue to occur despite safe injection guidelines.

Objective. The success of central line-associated bloodstream infection (CLABSI) prevention programs in intensive care units (ICUs) has led to the expansion of surveillance at many hospitals. We sought to compare non-ICU CLABSI (nCLABSI) rates with national reports and describe methods of surveillance at several participating US institutions. Design and Setting. An electronic survey of several medical centers about infection surveillance practices and rate data for non-ICU patients. Participants. Ten tertiary care hospitals. Methods. In March 2011, a survey was sent to 10 medical centers. The survey consisted of 12 questions regarding demographics and CLABSI surveillance methodology for non-ICU patients at each center. Participants were also asked to provide available rate and device utilization data. Results. Hospitals ranged in size from 238 to 1,400 total beds (median, 815). All hospitals reported using Centers for Disease Control and Prevention (CDC) definitions. Denominators were collected by different means: counting patients with central lines every day (5 hospitals), indirectly estimating on the basis of electronic orders ([Formula: see text]), or another automated method ([Formula: see text]). Rates of nCLABSI ranged from 0.2 to 4.2 infections per 1,000 catheter-days (median, 2.5). The national rate reported by the CDC using 2009 data from the National Healthcare Surveillance Network was 1.14 infections per 1,000 catheter-days. Conclusions. Only 2 hospitals were below the pooled CLABSI rate for inpatient wards; all others exceeded this rate. Possible explanations include differences in average central line utilization or hospital size in the impact of certain clinical risk factors notably absent from the definition and in interpretation and reporting practices. Further investigation is necessary to determine whether the national benchmarks are low or whether the hospitals surveyed here represent a selection of outliers.