Gail Potter-Bynoe

ENVIRONMENTAL CONTAMINATION DUE TO METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS: POSSIBLE INFECTION CONTROL IMPLICATIONS

OBJECTIVE To study the possible role of contaminated environmental surfaces as a reservoir of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals. DESIGN A prospective culture survey of inanimate objects in the rooms of patients with MRSA. SETTING A 200-bed university-affiliated teaching hospital. PATIENTS Thirty-eight consecutive patients colonized or infected with MRSA. Patients represented endemic MRSA cases. RESULTS Ninety-six (27%) of 350 surfaces sampled in the rooms of affected patients were contaminated with MRSA. When patients had MRSA in a wound or urine, 36% of surfaces were contaminated. In contrast, when MRSA was isolated from other body sites, only 6% of surfaces were contaminated (odds ratio, 8.8; 95% confidence interval, 3.7-25.5; P < .0001). Environmental contamination occurred in the rooms of 73% of infected patients and 69% of colonized patients. Frequently contaminated objects included the floor, bed linens, the patients gown, overbed tables, and blood pressure cuffs. Sixty-five percent of nurses who had performed morning patient-care activities on patients with MRSA in a wound or urine contaminated their nursing uniforms or gowns with MRSA. Forty-two percent of personnel who had no direct contact with such patients, but had touched contaminated surfaces, contaminated their gloves with MRSA. CONCLUSIONS We concluded that inanimate surfaces near affected patients commonly become contaminated with MRSA and that the frequency of contamination is affected by the body site at which patients are colonized or infected. That personnel may contaminate their gloves (or possibly their hands) by touching such surfaces suggests that contaminated environmental surfaces may serve as a reservoir of MRSA in hospitals.

Parallel bacterial evolution within multiple patients identifies candidate pathogenicity genes

Bacterial pathogens evolve during the infection of their human host, but separating adaptive and neutral mutations remains challenging. Here we identify bacterial genes under adaptive evolution by tracking recurrent patterns of mutations in the same pathogenic strain during the infection of multiple individuals. We conducted a retrospective study of a Burkholderia dolosa outbreak among subjects with cystic fibrosis, sequencing the genomes of 112 isolates collected from 14 individuals over 16 years. We find that 17 bacterial genes acquired nonsynonymous mutations in multiple individuals, which indicates parallel adaptive evolution. Mutations in these genes affect important pathogenic phenotypes, including antibiotic resistance and bacterial membrane composition and implicate oxygen-dependent regulation as paramount in lung infections. Several genes have not previously been implicated in pathogenesis and may represent new therapeutic targets. The identification of parallel molecular evolution as a pathogen spreads among multiple individuals points to the key selection forces it experiences within human hosts.

Systematic Intervention to Reduce Central Line–Associated Bloodstream Infection Rates in a Pediatric Cardiac Intensive Care Unit

OBJECTIVE. Our goal was to determine whether an intervention involving staff education, increased awareness, and practice changes would decrease central line–associated bloodstream infection rates in a pediatric cardiac ICU. METHODS. A retrospective, interventional study using an interrupted time-series design was conducted to compare central line–associated bloodstream infection rates during 3 time periods for all patients admitted to our pediatric cardiac ICU between April 1, 2004, and December 31, 2006. During the preintervention period (April 2004 to December 2004), a committee was convened to track and prevent nosocomial infections. Pretesting demonstrated knowledge deficits regarding nosocomial infection prevention, and educational tools were developed. During the partial intervention period (January 2005 to March 2006), a comprehensive central line–associated bloodstream infection prevention initiative was implemented, including establishment of a unit-based infection control nurse position, education for physicians and nurses, real-time feedback on central line–associated bloodstream infection data, implementation of central venous line insertion, access, and maintenance bundles, and introduction of daily goal sheets on rounds that emphasized timely central venous line removal. Central line–associated bloodstream infection rates in the preintervention, partial intervention, and full intervention (April 2006 to December 2006) periods were compared. RESULTS. The estimated mean preintervention central line–associated bloodstream infection rate was 7.8 infections per 1000 catheter-days, which decreased to 4.7 infections per 1000 catheter-days in the partial intervention period and 2.3 infections per 1000 catheter-days in the full intervention period. The preintervention central line–associated bloodstream infection rate was significantly higher than the median rate of 3.5 infections per 1000 catheter-days for multidisciplinary PICUs reporting to the National Healthcare Safety Network. During the full intervention period, our central line–associated bloodstream infection rate was lower than this pediatric benchmark, although statistical significance was not achieved. CONCLUSIONS. A multidisciplinary, evidence-based initiative resulted in a significant reduction in central line–associated bloodstream infections in our pediatric cardiac ICU.

Interventional study to evaluate the impact of an alcohol-based hand gel in improving hand hygiene compliance.

Objective. To evaluate the effects of the introduction of an alcohol-based hand gel and multifaceted quality improvement (QI) interventions on hand hygiene (HH) compliance. Design. Interventional, randomized cohort study with four study phases (baseline; limited intervention in two units; full intervention in three units; washout phase), performed in three intensive care units at a pediatric referral hospital. Methods. During 724 thirty-minute daytime monitoring sessions, a nonidentified observer witnessed 12 216 opportunities for HH and recorded compliance. Interventions. Introduction of an alcohol-based hand gel; multifaceted QI interventions (educational program, opinion leaders, performance feedback). Results. Baseline compliance decreased after the first 2 weeks of observation from 42.5% to 28.2% (presumably because of waning of a Hawthorne effect), further decreased to 23.3% in the limited intervention phase and increased to 35.1% after the introduction of a hand gel with QI support in all three units (P < 0.001). The rise in compliance persisted in the last phase (compliance, 37.2%); however, a gradual decline was observed during the final weeks. Except for the limited intervention phase, compliance achieved through standard handwashing and glove use remained stable around 20 and 10%, respectively, whereas compliance achieved through gel use increased to 8% (P < 0.001). After adjusting for confounding, implementation of the hand gel with QI support remained significantly associated with compliance (odds ratio, 1.6; 95% confidence interval, 1.4 to 1.8). In a final survey completed by 62 staff members, satisfaction with the hand gel was modest (45%). Conclusions. We noted a statistically significant, modest improvement in compliance after introduction of an alcohol-based hand gel with multifaceted QI support. When appropriately implemented, alcohol-based HH may be effective in improving compliance.

Epidemiology and risk factors for Clostridium difficile infection in children.

Background: Pediatric Clostridium difficile infection (CDI)-related hospitalizations are increasing. We sought to describe the epidemiology of pediatric CDI at a quaternary care hospital. Methods: Nested case-control study within a cohort of children <18 years tested for C. difficile between January and August 2008. The study included patients who were ≥1 year with a positive test and diarrhea; those without diarrhea (ie, presumed colonization) were excluded. Two unmatched controls per case were randomly selected from patients ≥1 year with a negative test. Potential predictors of CDI included age, gender, comorbidities, prior hospitalization, receipt of C. difficile-active antibiotics in the prior 24 hours, and recent (≤4 weeks) exposure to antibiotics or acid-blocking medications. Multivariate logistic regression models were created to identify independent predictors of CDI. Results: Of 1891 tests performed, 263 (14%) were positive in 181 children. Ninety-five patients ≥1 year with CDI were compared with 238 controls. In multivariate analyses, predictors of CDI included solid organ transplant (odds ratio [OR], 8.09; 95% confidence interval [CI], 2.10–31.12), lack of prior hospitalization (OR, 8.43; 95% CI, 4.39–16.20), presence of gastrostomy or jejunostomy (G or J) tube (OR, 3.32; 95% CI 1.71–6.42), and receipt of fluoroquinolones (OR, 17.04; 95% CI, 5.86–49.54) or nonquinolone antibiotics (OR, 2.23; 95% CI, 1.18–4.20) in the past 4 weeks. Receipt of C. difficile-active antibiotics within 24 hours before testing was associated with a lower odds of CDI (OR, 0.22; 95% CI, 0.09–0.58). Conclusions: Recent antibiotic exposure and certain comorbid conditions (solid organ transplant, presence of a gastrostomy or jejunostomy tube) were associated with CDI. Diagnostic testing has less utility in patients being treated with C. difficile-active antibiotics.

Emergence and nosocomial transmission of ampicillin-resistant enterococci.

Between 1986 and 1988, the incidence of ampicillin-resistant enterococci increased sevenfold at a university-affiliated hospital. Forty-three patients acquired nosocomial infections with ampicillin-resistant enterococci, most of which were also resistant to mezlocillin, piperacillin, and imipenem. An analysis of plasmid and chromosomal DNAs of isolates revealed that the increase was due to an epidemic of 19 nosocomial infections that yielded closely related strains of Enterococcus faecium and to a significant increase in the incidence of nonepidemic, largely unrelated strains of ampicillin-resistant enterococci. The nonepidemic strains were identified as E. faecium, E. raffinosus, E. durans, and E. gallinarum. A logistic regression analysis revealed that patients with nonepidemic resistant strains were 16 times more likely than controls to have received preceding therapy with imipenem. In our institution, the increase in the incidence of ampicillin-resistant enterococci appears to be due to the selection of various strains of resistant enterococci by the use of imipenem and to the nosocomial transmission of E. faecium and E. raffinosus. Images

Risk Factors for Surgical Site Infection After Cardiac Surgery in Children

BACKGROUND We sought to identify risk factors for surgical site infections (SSI) in children undergoing cardiac surgery. METHODS A matched case-control study was conducted in the Childrens Hospital Boston Cardiovascular Program. Surgical site infections were identified for 3 years (2004 to 2006). We identified two randomly selected control patients who underwent cardiac surgery within 7 days of each index case. Univariate and multivariate conditional logistic regression analyses were used to identify risk factors for SSI. In a secondary analysis, risk factors for organ space SSI (mediastinitis) were sought. Secondary analyses were also conducted using only those variables known preoperatively. RESULTS Seventy-two SSI and 144 controls were included. Independent risk factors for any type of SSI were age younger than 1 year (adjusted odds ratio, 2.28; 95% confidence interval, 1.18 to 4.39) and duration of cardiopulmonary bypass greater than 105 minutes (adjusted odds ratio, 1.92; 95% confidence interval, 1.02 to 3.62). Independent risk factors for organ space SSI were aortic cross-clamp time greater than 85 minutes (adjusted odds ratio, 5.61; 95% confidence interval, 1.06 to 29.67) and postoperative exposure to at least three separate red blood cell transfusions (adjusted odds ratio, 7.87; 95% confidence interval, 1.63 to 37.92). When only those potential risk factors known preoperatively were considered, age younger than 1 year independently predicted the subsequent development of any type of SSI, and preoperative hospitalization independently predicted the subsequent development of organ space SSI. CONCLUSIONS Younger patients undergoing longer surgical procedures and those requiring more postoperative blood transfusions are at greatest risk for SSI. Additional preventive strategies, including restrictive blood transfusion policies, warrant further investigation.

Risk factors for central line-associated bloodstream infection in a pediatric cardiac intensive care unit

Objective: To identify risk factors for central line-associated bloodstream infection (BSI) in patients receiving care in a pediatric cardiac intensive care unit. Design: Matched case-control study. Setting: CICU at Childrens Hospital Boston. Patients: Central line-associated BSI cases were identified between April 2004 and December 2006. We identified two randomly selected control patients who had a central vascular catheter and were admitted within 7 days of each index case. Measurements and Main Results: Univariate and multivariate conditional logistic regression analyses were used to identify risk factors for central line-associated BSI. In a secondary analysis, risk factors for central line-associated BSI in those cases who underwent cardiac surgery were sought. During the study period, 67 central line-associated BSIs occurred in 61 patients. Independent risk factors for central line-associated BSI were nonelective admission for medical management (odds ratio [OR] = 6.51 [1.58–26.78]), the presence of noncardiac comorbidities (OR = 4.95 [1.49–16.49]), initial absolute neutrophil count <5000 cells/uL (OR = 6.17 [1.39–27.48]), blood product exposure ≥3 units (OR = 5.56 [1.35–22.87]), central line days ≥7 (OR = 6.06 [1.65–21.83]), and use of hydrocortisone (OR = 28.94 [2.55–330.37]). In those patients who underwent cardiac surgery (n = 37 cases and 108 controls), independent risk factors for central line-associated BSI were admission weight ≤5 kg (OR = 3.13 [1.01–9.68]), Pediatric Risk of Mortality III score ≥15 (OR = 3.44 [1.19–9.92]), blood product exposure ≥3 units (OR = 3.38 [1.28–11.76]), and mechanical ventilation for ≥7 days (OR = 4.06 [1.33–12.40]). Conclusions: Unscheduled medical admissions, presence of noncardiac comorbidities, extended device utilization, and specific medical therapies are independent risk factors for central line-associated BSI in patients receiving care in a pediatric cardiac intensive care unit.

Risk factors for central line-associated bloodstream infection in pediatric intensive care units.

OBJECTIVE We sought to identify risk factors for central line-associated bloodstream infection (CLABSI) to describe children who might benefit from adjunctive interventions. DESIGN Case-control study of children admitted to the medical-surgical intensive care unit (ICU) or cardiac ICU from January 1, 2004, through December 31, 2007. SETTING Childrens Hospital Boston is a freestanding, 396-bed quaternary care pediatric hospital with a 29-bed medical-surgical ICU and a 24-bed cardiac ICU. PATIENTS Case patients were patients with CLABSI who were identified by means of prospective surveillance. Control subjects were patients with a central venous catheter who were matched by ICU admission date. METHODS Multivariate conditional logistic regression models were used to identify independent risk factors for CLABSI and to derive and to validate a prediction rule. RESULTS Two hundred three case patients were matched with 406 control subjects. Independent predictors of CLABSI included duration of ICU central access (odds ratio [OR] for 15 or more days, 18.41 [95% confidence interval {CI}, 4.10-82.56]; P < .001), central venous catheter placement in the ICU (OR for 2 or more ICU-placed catheters, 8.63 [95% CI, 2.63-28.38]; P = .001), nonoperative cardiovascular disease (OR, 7.44 [95% CI, 2.13-25.98]; P = .012), presence of gastrostomy tube (OR, 3.48 [95% CI, 1.55-7.79]; P = .003), receipt of parenteral nutrition (OR, 3.12 [95% CI, 1.55-6.32]; P = .002), and receipt of blood transfusion (OR, 2.55 [95% CI, 1.21-5.36]; P = .014). By use of risk factors known before central venous catheter placement, our model predicted CLABSI with a positive predictive value of 54% and a negative predictive value of 79%. CONCLUSIONS Duration of central access, receipt of parenteral nutrition, and receipt of blood transfusion were confirmed as risk factors for CLABSI among children in the ICU. Newly identified risk factors include presence of gastrostomy tube, nonoperative cardiovascular disease, and ICU placement of central venous catheter. Children with these risk factors may be candidates for adjunctive interventions for CLABSI prevention.

Moving CLABSI Prevention beyond the Intensive Care Unit: Risk Factors in Pediatric Oncology Patients

BACKGROUND AND OBJECTIVE Central line-associated bloodstream infections (CLABSIs) frequently complicate the use of central venous catheters (CVCs) among pediatric patients with cancer. Our objectives were to describe the microbiology and identify risk factors for hospital-onset CLABSI in this patient population. DESIGN Retrospective case-control study. SETTING Oncology and stem cell transplant units of a freestanding, 396-bed quaternary care pediatric hospital. PARTICIPANTS Case subjects ([Formula: see text]) were patients with a diagnosis of malignancy and/or stem cell transplant recipients with CLABSI occurring during admission. Controls ([Formula: see text]) were identified using risk set sampling of hospitalizations among patients with a CVC, matched on date of admission. METHODS Multivariate conditional logistic regression was used to identify independent predictors of CLABSI. RESULTS The majority of CLABSI isolates were gram-positive bacteria (58%). The most frequently isolated organism was Enterococcus faecium, and 6 of 9 isolates were resistant to vancomycin. In multivariate analyses, independent risk factors for CLABSI included platelet transfusion within the prior week (odds ratio [OR], 10.90 [95% confidence interval (CI), 3.02-39.38]; [Formula: see text]) and CVC placement within the previous month (<1 week vs ≥1 month: OR, 11.71 [95% CI, 1.98-69.20]; [Formula: see text]; ≥1 week and <1 month vs ≥1 month: OR, 7.37 [95% CI, 1.85-29.36]; [Formula: see text]). CONCLUSIONS Adjunctive measures to prevent CLABSI among pediatric oncology patients may be most beneficial in the month following CVC insertion and in patients requiring frequent platelet transfusions. Vancomycin-resistant enterococci may be an emerging cause of CLABSI in hospitalized pediatric oncology patients and are unlikely to be treated by typical empiric antimicrobial regimens.