Alexandre R. Marra

Nosocomial Bloodstream Infections in Brazilian Hospitals: Analysis of 2,563 Cases from a Prospective Nationwide Surveillance Study

ABSTRACT Nosocomial bloodstream infections (nBSIs) are an important cause of morbidity and mortality. Data from a nationwide, concurrent surveillance study, Brazilian SCOPE (Surveillance and Control of Pathogens of Epidemiological Importance), were used to examine the epidemiology and microbiology of nBSIs at 16 Brazilian hospitals. In our study 2,563 patients with nBSIs were included from 12 June 2007 to 31 March 2010. Ninety-five percent of BSIs were monomicrobial. Gram-negative organisms caused 58.5% of these BSIs, Gram-positive organisms caused 35.4%, and fungi caused 6.1%. The most common pathogens (monomicrobial) were Staphylococcus aureus (14.0%), coagulase-negative staphylococci (CoNS) (12.6%), Klebsiella spp. (12.0%), and Acinetobacter spp. (11.4%). The crude mortality was 40.0%. Forty-nine percent of nBSIs occurred in the intensive-care unit (ICU). The most frequent underlying conditions were malignancy, in 622 patients (24.3%). Among the potential factors predisposing patients to BSI, central venous catheters were the most frequent (70.3%). Methicillin resistance was detected in 157 S. aureus isolates (43.7%). Of the Klebsiella sp. isolates, 54.9% were resistant to third-generation cephalosporins. Of the Acinetobacter spp. and Pseudomonas aeruginosa isolates, 55.9% and 36.8%, respectively, were resistant to imipenem. In our multicenter study, we found high crude mortality and a high proportion of nBSIs due to antibiotic-resistant organisms.

Nosocomial bloodstream infections caused by Klebsiella pneumoniae: impact of extended-spectrum β-lactamase (ESBL) production on clinical outcome in a hospital with high ESBL prevalence

BackgroundThe frequency of ESBL producing Klebsiella pneumoniae bloodstream infections (BSI) is high in Brazilian hospitals, however little is known regarding what role, if any, resistance plays in the expected outcome in hospitals with a high prevalence of these pathogens.MethodsFrom 1996 to 2001, hospital acquired K. pneumoniae BSI were evaluated retrospectively. Each patient was included only once at the time of BSI. ESBL producing strains were identified using the E-test method. The association of variables with the mortality related to bacteremia was included in a stepwise logistic regression model.ResultsOne hundred and eight hospital acquired K. pneumoniae BSI met criteria for inclusion. Fifty two percent were due to ESBL producing strains. The overall in-hospital mortality was 40.8%. Variables independently predicting death by multivariate analysis were the following: mechanical ventilation (p = 0.001), number of comorbidities (p = 0.003), antimicrobials prescribed before bacteremia (p = 0.01) and fatal underlying disease (p = 0.025).ConclusionBacteremia due to ESBL producing K. pneumoniae strains was not an independent predictor for death in patients with BSI. An increased mortality in hospital-acquired BSI by K. pneumoniae was related to the requirement for mechanical ventilation, more than two comorbidities, the previous use of two or more antibiotics, and the presence of a rapidly fatal disease.

Positive Deviance: A New Strategy for Improving Hand Hygiene Compliance

OBJECTIVE To evaluate the effectiveness of a positive deviance strategy for the improvement of hand hygiene compliance in 2 adult step-down units. DESIGN A 9-month, controlled trial comparing the effect of positive deviance on compliance with hand hygiene. SETTING Two 20-bed step-down units at a tertiary care private hospital. METHODS The first phase of our study was a 3-month baseline period (from April to June 2008) in which hand hygiene episodes were counted by use of electronic handwashing counters. From July to September 2008 (ie, the second phase), a positive deviance strategy was implemented in the east unit; the west unit was the control unit. During the period from October to December 2008 (ie, the third phase), positive deviance was applied in both units. RESULTS During the first phase, there was no statistically significant difference between the 2 step-down units in the number of episodes of hand hygiene per 1,000 patient-days or in the incidence density of healthcare-associated infections (HAIs) per 1,000 patient-days. During the second phase, there were 62,000 hand hygiene episodes per 1,000 patient-days in the east unit and 33,570 hand hygiene episodes per 1,000 patient-days in the west unit (P < .01 ). The incidence density of HAIs per 1,000 patient-days was 6.5 in the east unit and 12.7 in the west unit (p = .04). During the third phase, there was no statistically significant difference in hand hygiene episodes per 1,000 patient-days (P = .16) or in incidence density of HAIs per 1,000 patient-days. CONCLUSION A positive deviance strategy yielded a significant improvement in hand hygiene, which was associated with a decrease in the overall incidence of HAIs.

Bloodstream Infections with Metallo-β-Lactamase-Producing Pseudomonas aeruginosa: Epidemiology, Microbiology, and Clinical Outcomes

ABSTRACT Pseudomonas aeruginosa strains that produce metallo-β-lactamases (MBLs) are becoming increasingly prevalent. We evaluated the epidemiological and microbiological characteristics of monomicrobial bloodstream infections caused by MBL-producing P. aeruginosa isolates, as well as the clinical outcomes in patients with these infections.

Epidemiology of bloodstream infections in patients receiving long-term total parenteral nutrition

Goals To describe the epidemiology and microbiologic characteristics of bloodstream infections (BSIs) in patients receiving long-term total parenteral nutrition (TPN). Background Home TPN therapy has been reported as a risk factor for BSI. However, little knowledge exists regarding the epidemiology of BSIs in this patient group. Study A descriptive, observational epidemiologic study of patients receiving long-term TPN from January 1981 to July 2005 was performed. Variables analyzed include age, gender, time of follow-up, number of BSIs, microbiologic characteristics, underlying disease necessitating long-term TPN, catheter type, complications related to TPN, and clinical outcome. Results Forty-seven patients receiving long-term TPN were evaluated. The most frequent indication for long-term TPN was ischemic bowel disease (25.5%). The mean duration of follow-up was 4.5 years. Thirty-eight patients (80.9%) developed 248 BSIs while receiving TPN. More than 1 BSI episode occurred in 78.9% of these patients, and 23.8% of BSI episodes were polymicrobial. The most prevalent pathogen was coagulase negative staphylococci (33.5%). The most frequent complication among patients with BSI was central venous thrombosis (44.7%). Five patients were intravenous drug users. There were 11 deaths among the patients on long-term TPN, 4 of these were related to infection and 4 were related to intravenous drug use. Conclusions The incidence of BSI is high, and a significant proportion of BSIs in long-term TPN patients are polymicrobial and due to multidrug-resistant bacteria and fungi. Careful management of the infusion line is required and interventions are needed to reduce the risk of catheter-related infections in this population.

Successful prevention of ventilator-associated pneumonia in an intensive care setting

BACKGROUND Ventilator-associated pneumonia (VAP) is one of the most common health care-associated infections (HAIs) in critical care settings. OBJECTIVE Our objective was to examine the effect of a series of interventions, implemented in 3 different periods to reduce the incidence of VAP in an intensive care unit (ICU). METHODS A quasiexperimental study was conducted in a medical-surgical ICU. Multiple interventions to optimize VAP prevention were performed during different phases. From March 2001 to December 2002 (phase 1: P1), some Centers for Disease Control and Prevention (CDC) evidence-based practices were implemented. From January 2003 to December 2006 (P2), we intervened in these processes at the same time that performance monitoring was occurring at the bedside, and, from January 2007 to September 2008 (P3), we continued P2 interventions and implemented the Institute for Healthcare Improvements ventilator bundle plus oral decontamination with chlorhexidine and continuous aspiration of subglottic secretions. RESULTS The incidence density of VAP in the ICU per 1000 patient-days was 16.4 in phase 1, 15.0 in phase 2, and 10.4 in phase 3, P=.05. Getting to zero VAP was possible only in P3 when compliance with all interventions exceeded 95%. CONCLUSION These results suggest that reducing VAP rates to zero is a complex process that involves multiple performance measures and interventions.

Time to Blood Culture Positivity as a Predictor of Clinical Outcome of Staphylococcus aureus Bloodstream Infection

ABSTRACT Few studies have assessed the time to blood culture positivity as a predictor of clinical outcome in bloodstream infections (BSIs). The purpose of this study was to evaluate the time to positivity (TTP) of blood cultures in patients with Staphylococcus aureus BSIs and to assess its impact on clinical outcome. We performed a historical cohort study with 91 adult patients with S. aureus BSIs. TTP was defined as the time between the start of incubation and the time that the automated alert signal indicating growth in the culture bottle sounded. Patients with BSIs and TTPs of culture of ≤12 h (n = 44) and >12 h (n = 47) were compared. Septic shock occurred in 13.6% of patients with TTPs of ≤12 h and in 8.5% of patients with TTP of >12 h (P = 0.51). A central venous catheter source was more common with a BSI TTP of ≤12 h (P = 0.010). Univariate analysis revealed that a Charlson score of ≥3, the failure of at least one organ (respiratory, cardiovascular, renal, hematologic, or hepatic), infection with methicillin-resistant S. aureus, and TTPs of ≤12 h were associated with death. Age, gender, an APACHE II score of ≥20 at BSI onset, inadequate empirical antibiotic therapy, hospital-acquired bacteremia, and endocarditis were not associated with mortality. Multivariate analysis revealed that independent predictors of hospital mortality were a Charlson score of ≥3 (odds ratio [OR], 14.4; 95% confidence interval [CI], 2.24 to 92.55), infection with methicillin-resistant S. aureus (OR, 9.3; 95% CI, 1.45 to 59.23), and TTPs of ≤12 h (OR, 6.9; 95% CI, 1.07 to 44.66). In this historical cohort study of BSIs due to S. aureus, a TTP of ≤12 h was a predictor of the clinical outcome.

A hospital-based matched case-control study to identify clinical outcome and risk factors associated with carbapenem-resistant Klebsiella pneumoniae infection.

BackgroundHealthcare-associated infections caused by Klebsiella pneumoniae isolates are increasing and few effective antibiotics are currently available to treat patients. We observed decreased carbapenem susceptibility among K. pneumoniae isolated from patients at a tertiary private hospital that showed a phenotype compatible with carbapenemase production although this group of enzymes was not detected in any sample. The aim of this study was to describe the epidemiology and clinical outcomes associated with carbapenem-resistant K. pneumoniae and to determine the antimicrobial resistance mechanisms.MethodsRisk factors associated with carbapenem-resistant K. pneumoniae infections were investigated by a matched case–control study from January 2006 through August 2008. A cohort study was also performed to evaluate the association between carbapenem resistance and in-hospital mortality. Bacterial identification and antimicrobial susceptibility were determined by Vitek 2 and Etest. Carbapenemase activity was detected using spectrophotometric assays. Production of beta-lactamases and alterations in genes encoding K. pneumoniae outer membrane proteins, OmpK35 and OmpK36, were analyzed by PCR and DNA sequencing, as well as SDS-Page. Genetic relatedness of carbapenem resistant isolates was evaluated by Pulsed Field Gel Electrophoresis.ResultsSixty patients were included (20 cases and 40 controls) in the study. Mortality was higher for patients with carbapenem-resistant K. pneumoniae infections compared with those with carbapenem-susceptible K. pneumoniae (50.0% vs 25.7%). The length of central venous catheter use was independently associated with carbapenem resistance in the multivariable analysis. All strains, except one, carried blaCTX-M-2, an extended-spectrum betalactamase gene. In addition, a single isolate also possessed blaGES-1. Genes encoding plasmid-mediated AmpC beta-lactamases or carbapenemases (KPC, metallo-betalactamases or OXA-carbapenemases) were not detected.ConclusionsThe K. pneumoniae multidrug-resistant organisms were associated with significant mortality. The mechanisms associated with decreased K. pneumoniae carbapenem susceptibility were likely due to the presence of cephalosporinases coupled with porin alterations, which resulted from the presence of the insertion sequences in the outer membrane encoding genes.

Impact of a program to prevent central line-associated bloodstream infection in the zero tolerance era

BACKGROUND Central line-associated bloodstream infection (CLABSI) is one of the most important health care-associated infections in the critical care setting. METHODS A quasiexperimental study involving multiple interventions to reduce the incidence of CLABSI was conducted in a medical-surgical intensive care unit (ICU) and in 2 step-down units (SDUs). From March 2005 to March 2007 (phase 1 [P1]), some Centers for Disease Control and Prevention evidence-based practices were implemented. From April 2007 to April 2009 (P2), we intervened in these processes at the same time that performance monitoring was occurring at the bedside, and we implemented the Institute for Healthcare Improvement central line bundle for all ICU and SDU patients requiring central venous lines. RESULTS The mean incidence density of CLABSI per 1000 catheter-days in the ICU was 6.4 in phase 1 and 3.2 in phase 2, P < .001. The mean incidence density of CLABSI per 1000 catheter-days in the SDUs was 4.1 in phase 1 and 1.6 in phase 2, P = .005. CONCLUSION These results suggest that reducing CLABSI rates in an ICU setting is a complex process that involves multiple performance measures and interventions that can also be applied to SDU settings.

Positive deviance: A program for sustained improvement in hand hygiene compliance

BACKGROUND There is a paucity of data evaluating whether positive deviance (PD) can sustain improvement in hand hygiene compliance. METHODS An observational study comparing the effect of PD on compliance with hand hygiene was conducted in two 20-bed step-down units (SDUs) at a private tertiary care hospital. In a 3-month baseline period (April-June 2008), hand hygiene counts were performed by electronic handwashing counters. Between July 1, 2008, and November 30, 2009, (East SDU) and between September 30, 2008, and December 2009 (West SDU), PD was applied in both units. RESULTS There was more than a 2-fold difference in the number of alcohol gel aliquots dispensed per month from April 2008 (before PD) to November 2009 (last month in PD) in the East SDU. There was also a 2-fold difference in the number of alcohol gel aliquots dispensed per month from September 2008 (before PD) to December 2009 (last month in PD) in the West SDU. The difference in the rate of health care‒associated infections (HAIs) between the baseline period and 2009 was statistically significant in the East SDU (5.8 vs 2.8 per 1,000 device-days; P = .008) and in the West SDU (3.7 vs 1.7 per 1,000 device-days; P = .023). CONCLUSIONS PD was responsible for a sustained improvement in hand hygiene in the inpatient setting and was associated with a decrease in the incidence of device-associated HAIs.