Coagulase-negative staphylococci (CNS) are the major cause of nosocomial bloodstream infection. Emergence of vancomycin resistance among CNS is a serious public health concern, because CNS usually are multidrug-resistant, and glycopeptide antibiotics, among which only vancomycin is available in the United States, are the only remaining effective therapy. In this report, we describe the first bloodstream infection in the United States associated with a Staphylococcus epidermidis strain with decreased susceptibility to vancomycin.

We reviewed the hospital's microbiology records for all CNS strains, reviewed the patient's medical and laboratory records, and obtained all available CNS isolates with decreased susceptibility to vancomycin. Blood cultures were processed and CNS isolates identified by using standard methods; antimicrobial susceptibility was determined by using minimum inhibitory concentration (MIC) and disk-diffusion methods. Nares cultures were obtained from exposed healthcare workers (HCWs) to identify possible colonization by CNS with decreased susceptibility to vancomycin.

The bloodstream infection by an S epidermidis strain with decreased susceptibility to vancomycin occurred in a 49-year-old woman with carcinoma. She had two blood cultures positive for CNS; both isolates were S epidermidis. Although susceptible to vancomycin by the disk-diffusion method (16-17 mm), the isolates were intermediate by MIC (8-6 μg/mL). The patient had received an extended course of vancomycin therapy; she died of her underlying disease. No HCW was colonized by CNS with decreased susceptibility to vancomycin.

This is the first report in the United States of bloodstream infection due to S epidermidis with decreased susceptibility to vancomycin. Contact precautions likely played a role in preventing nosocomial transmission of this strain, and disk-diffusion methods may be inadequate to detect CNS with decreased susceptibility to vancomycin.

In September 2006, the Centers for Disease Control and Prevention was notified of cases of gram-negative bloodstream infection (BSI) occurring among outpatients who received an intravenous formulation of the prostanoid treprostinil. An investigation was conducted to determine rates of prostanoid-associated BSI in this patient population and possible risk factors for infection.

We performed a retrospective cohort study of patients who had received intravenous formulations of at least 1 of the 2 approved prostanoids (epoprostenol and treprostinil) from January 1, 2004, through late 2006. Chart reviews were conducted at 2 large centers for pulmonary arterial hypertension, and a survey of infection control practices was conducted at 1 center.

A total of 224 patients were given intravenous prostanoid treatment, corresponding to 146,093 treatment-days during the study period. Overall, there were 0.55 cases of BSI and 0.18 cases of BSI due to gram-negative organisms per 1,000 treatment-days. BSI rates were higher for patients who received intravenous treprostinil than for patients who received intravenous epoprostenol (1.13 vs. 0.42 BSIs per 1,000 treatment-days; P < .001), as were rates of BSI due to gram-negative organisms (0.81 vs. 0.04 BSIs per 1,000 treatment-days; P < .001). Adjusted hazard ratios for all BSIs and for BSIs due to gram-negative organisms were higher among patients given treatment with intravenous treprostinil. The survey identified no significant differences in medication-related infection control practices.

At 2 centers, BSI due to gram-negative pathogens was more common than previously reported and was more frequent among patients given treatment with intravenous treprostinil than among patients given treatment with intravenous epoprostenol. Whether similar results would be found at other centers for pulmonary arterial hypertension warrants further investigation. This investigation underscores the importance of surveillance and evaluation of healthcare-related adverse events in patients given treatment primarily as outpatients.

To determine whether introduction of a needleless mechanical valve device (NMVD) at a long-term acute care hospital was associated with an increased frequency of catheter-related bloodstream infection (BSI).

For patients with a central venous catheter in place, the catheter-related BSI rate during the 24-month period before introduction of the NMVD, a period in which a needleless split-septum device (NSSD) was being used (hereafter, the NSSD period), was compared with the catheter-related BSI rate during the 24-month period after introduction of the NMVD (hereafter, the NMVD period). The microbiological characteristics of catheter-related BSIs during each period were also compared. Comparisons and calculations of relative risks (RRs) with 95% confidence intervals (CIs) were performed using χ2 analysis.

Eighty-six catheter-related BSIs (3.86 infections per 1,000 catheter-days) occurred during the study period. The rate of catheter-related BSI during the NMVD period was significantly higher than that during the NSSD period (5.95 vs 1.79 infections per 1,000 catheter-days; RR, 3.32 [95% CI, 2.88–3.83]; P < .001). A significantly greater percentage of catheter-related BSIs during the NMVD period were caused by gram-negative organisms, compared with the percentage recorded during the NSSD period (39.5% vs 8%; P = .007). Among catheter-related BSIs due to gram-positive organisms, the percentage caused by enterococci was significantly greater during the NMVD period, compared with the NSSD period (54.8% vs 13.6%; P = .004). The catheter-related BSI rate remained high during the NMVD period despite several educational sessions regarding proper use of the NMVD.

An increased catheter-related BSI rate was temporally associated with use of a NMVD at the study hospital, despite several educational sessions regarding proper NMVD use. The current design of the NMVD may be unsafe for use in certain patient populations.

Before-after prospective surveillance study to assess the efficacy of the International Nosocomial Infection Control Consortium (INICC) multidimensional infection control program to reduce the rate of occurrence of ventilator-associated pneumonia (VAP).

Neonatal intensive care units (NICUs) of INICC member hospitals from 15 cities in the following 10 developing countries: Argentina, Colombia, El Salvador, India, Mexico, Morocco, Peru, Philippines, Tunisia, and Turkey.

NICU inpatients.

VAP rates were determined during a first period of active surveillance without the implementation of the multidimensional approach (phase 1) to be then compared with VAP rates after implementation of the INICC multidimensional infection control program (phase 2), which included the following practices: a bundle of infection control interventions, education, outcome surveillance, process surveillance, feedback on VAP rates, and performance feedback on infection control practices. This study was conducted by infection control professionals who applied National Health Safety Network (NHSN) definitions for healthcare-associated infections and INICC surveillance methodology.

During phase 1, we recorded 3,153 mechanical ventilation (MV)–days, and during phase 2, after the implementation of the bundle of interventions, we recorded 15,981 MV-days. The VAP rate was 17.8 cases per 1,000 MV-days during phase 1 and 12.0 cases per 1,000 MV-days during phase 2 (relative risk, 0.67 [95% confidence interval, 0.50–0.91]; P = .001 ), indicating a 33% reduction in VAP rate.

Our results demonstrate that an implementation of the INICC multidimensional infection control program was associated with a significant reduction in VAP rate in NICUs in developing countries.

To describe the control of multidrug-resistant Acinetobacter baumannii-calcoaceticus (MDRABC) colonization and infection in an intensive care unit (ICU).

An 18-bed ICU in a large tertiary care teaching hospital in London.

After recognition of the outbreak, a range of infection control measures were introduced over several months that were primarily aimed at reducing environmental contamination with the outbreak strain. Strategies included use of a closed tracheal suction system for all patients receiving mechanical ventilation, use of nebulized colistin for patients with evidence of mild to moderate ventilator-associated pneumonia, improved availability of alcohol for hand decontamination, and clearer designation of responsibilities and strategies for cleaning equipment and the environment in the proximity of patients colonized or infected with MDRABC.

The outbreak lasted from June 2001 through November 2002 and involved 136 new cases of MDRABC infection or colonization. The number of newly diagnosed cases per month reached a maximum of 15 in February 2002, and the number of new cases slowly decreased over the next 9 months.

This outbreak was controlled by emphasizing the control of environmental reservoirs and did not require recourse to ward closure or placement of affected patients in isolation.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is resistant to almost all antimicrobial agents, and CRKP infections are associated with substantial morbidity and mortality.

To describe an outbreak of CRKP in Puerto Rico, determine risk factors for CRKP acquisition, and detail the successful measures taken to control the outbreak.

Two case-control studies.

A 328-bed tertiary care teaching hospital.

Twenty-six CRKP case patients identified during the outbreak period of February through September 2008, 26 randomly selected uninfected control patients, and 26 randomly selected control patients with carbapenem-susceptible K. pneumoniae (CSKP) hospitalized during the same period.

We performed active case finding, including retrospective review of the hospital's microbiology database and prospective perirectal surveillance culture sampling in high-risk units. Case patients were compared with each control group while controlling for time at risk. We sequenced the blaKPC gene with polymerase chain reaction for 7 outbreak isolates and subtyped these isolates with pulsed-field gel electrophoresis.

In matched, multivariable analysis, the presence of wounds (hazard ratio, 19.0 [95% confidence interval {CI}, 2.5-142.0]) was associated with CRKP compared with no K. pneumoniae. Transfer between units (adjusted odds ratio [OR], 7.5 [95% CI, 1.8-31.1]), surgery (adjusted OR, 4.0 [95% CI, 1.0-15.7]), and wounds (adjusted OR, 4.9 [95% CI, 1.1-21.8]) were independent risk factors for CRKP compared to CSKP. A novel K. pneumoniae carbapenemase variant (KPC-8) was present in 5 isolates. Implementation of active surveillance for CRKP colonization and cohorting of CRKP patients rapidly controlled the outbreak.

Enhanced surveillance for CRKP colonization and intensified infection control measures that include limiting the physical distribution of patients can reduce CRKP transmission during an outbreak.

To determine a potential source of MRSA colonization and infection among preterm infants in a neonatal intensive care unit (NICU) using molecular analysis of breast milk samples.

Case report, outbreak investigation.

Preterm triplets were delivered at 26 weeks' gestation via cesarean section when routine active surveillance for MRSA was performed for all infants in a NICU. Surveillance consisted of swabbing the throat, nose, and umbilicus (TNU) weekly. Although infants A and B initially had negative TNU swabs, repeat cultures were positive for MRSA on day of life (DOL) 10 and DOL 18, respectively. Surveillance and clinical cultures for infant C were negative. Infant A developed sepsis, and multiple blood cultures were positive for MRSA beginning on DOL 14. Infant B developed conjunctivitis and a conjunctival exudate culture was positive for MRSA on DOL 70. Both infants were fed breast milk via nasogastric tube. Cultures of breast milk samples for infants A and B dated prior to either infant's first positive surveillance culture were positive for MRSA. All MRSA isolates had identical results on antibiotic susceptibility testing. PFGE demonstrated identical banding patterns for the MRSA isolates from the blood culture of infant A, breast milk for infants A and B, and a surveillance swab from infant B. At no time did the mother develop evidence of mastitis or other local breast infection.

MRSA can be passed from mother to preterm infant through contaminated breast milk, even in the absence of maternal infection. Colonization and clinical disease can result.

To determine the impact of the screening test, nursing workload, handwashing rates, and dependence of handwashing on risk level of patient visit on methicillin-resistant Staphylococcus aureus (MRSA) transmission among hospitalized patients.

General medical ward.

Monte Carlo simulation was used to model MRSA transmission (median rate per 1,000 patient-days). Visits by healthcare workers (HCWs) to patients were simulated, and MRSA was assumed to be transmitted among patients via HCWs.

The transmission rate was reduced from 0.89 to 0.56 by the combination of increasing the sensitivity of the screening test from 80% to 99% and being able to report results in 1 day instead of 4 days. Reducing the patient-to-nurse ratio from 4.3 in the day and 6.8 at night to 3.8 and 5.7, respectively, reduced the number of nosocomial infections from 0.89 to 0.85; reducing the ratio to 1 and 1, respectively, further reduced the number of nosocomial infections to 0.32. Increases in handwashing rates by 0%, 10%, and 20% for high-risk visits yielded reductions in nosocomial infections similar to those yielded by increases in handwashing rates for all visits (0.89, 0.36, and 0.24, respectively). Screening all patients for MRSA at admission reduced the transmission rate to 0.81 per 1,000 patient-days from 1.37 if no patients were screened.

Within the ranges of parameters studied, the most effective strategies for reducing the rate of MRSA transmission were increasing the handwashing rates for visits involving contact with skin or bodily fluid and screening patients for MRSA at admission. (Infect Control Hosp Epidemiol 2005;26:607- 615)

To study the frequency of isolation of Acinetobacter baumannii complex (ABC) and methicillin-resistant Staphylococcus aureus (MRSA) from surfaces of rooms newly vacated by patients with multidrug-resistant (MDR) ABC following various rounds of routine terminal cleaning and disinfection (C/D) with bleach or 1 round of C/D followed by hydrogen peroxide vapor (HPV) treatment.

A 900-bed tertiary care hospital.

ABC and MRSA cultures were obtained from hospital rooms including 312 rooms (mean, 18.3 sites/room) following 4 rounds of C/D, 37 rooms (mean, 20 sites/room) following 1 round of C/D before and after HPV treatment, and 134 rooms (mean, 20 sites/room) following 1 round of C/D and HPV treatment.

Following 4 rounds of C/D, 83 (26.6%) rooms had 1 or more culture-positive sites; 102 (1.8%) sites in 51 (16.4%) rooms grew ABC, and 108 (1.9%) sites in 44 (14.1%) rooms grew MRSA. The addition of HPV treatment to 1 round of C/D resulted in a significant drop in ABC- and MRSA-positive room sites (odds ratio, 0 [95% confidence interval, 0–0.8]; P = .04 for both organisms). Following 1 round of C/D and HPV treatment, 6 (4.5%) rooms were culture-positive for ABC, MRSA, or both.

Routine terminal C/D of hospital rooms vacated by MDRABC-positive patients may be associated with a significant number of ABC- or MRSA-positive room surfaces even when up to 4 rounds of C/D are performed. The addition of HPV treatment to 1 round of C/D appears effective in reducing the number of persistently contaminated room sites in this setting.

To describe the control of multidrug-resistant Acinetobacter baumannii-calcoaceticus (MDRABC) colonization and infection in an intensive care unit (ICU).

An 18-bed ICU in a large tertiary care teaching hospital in London.

After recognition of the outbreak, a range of infection control measures were introduced over several months that were primarily aimed at reducing environmental contamination with the outbreak strain. Strategies included use of a closed tracheal suction system for all patients receiving mechanical ventilation, use of nebulized colistin for patients with evidence of mild to moderate ventilator-associated pneumonia, improved availability of alcohol for hand decontamination, and clearer designation of responsibilities and strategies for cleaning equipment and the environment in the proximity of patients colonized or infected with MDRABC.

The outbreak lasted from June 2001 through November 2002 and involved 136 new cases of MDRABC infection or colonization. The number of newly diagnosed cases per month reached a maximum of 15 in February 2002, and the number of new cases slowly decreased over the next 9 months.

This outbreak was controlled by emphasizing the control of environmental reservoirs and did not require recourse to ward closure or placement of affected patients in isolation.

Antimicrobial stewardship programs are being implemented in health care to reduce inappropriate antimicrobial use, adverse events, Clostridium difficile infection, and antimicrobial resistance. There is no standardized approach to evaluate the impact of these programs.

To use a structured panel process to define quality improvement metrics for evaluating antimicrobial stewardship programs in hospital settings that also have the potential to be used as part of public reporting efforts.

A multiphase modified Delphi technique.

Paper-based survey supplemented with a 1-day consensus meeting.

A 10-member expert panel from Canada and the United States was assembled to evaluate indicators for relevance, effectiveness, and the potential to aid quality improvement efforts.

There were a total of 5 final metrics selected by the panel: (1) days of therapy per 1000 patient-days; (2) number of patients with specific organisms that are drug resistant; (3) mortality related to antimicrobial-resistant organisms; (4) conservable days of therapy among patients with community-acquired pneumonia (CAP), skin and soft-tissue infections (SSTI), or sepsis and bloodstream infections (BSI); and (5) unplanned hospital readmission within 30 days after discharge from the hospital in which the most responsible diagnosis was one of CAP, SSTI, sepsis or BSI. The first and second indicators were also identified as useful for accountability purposes, such as public reporting.

We have successfully identified 2 measures for public reporting purposes and 5 measures that can be used internally in healthcare settings as quality indicators. These indicators can be implemented across diverse healthcare systems to enable ongoing evaluation of antimicrobial stewardship programs and complement efforts for improved patient safety.

Recent outbreaks of Clostridium difficile infection (CDI) have been difficult to control, and data indicate that the importance of different sources of transmission may have changed. Our objectives were to evaluate the contributions of asymptomatic and symptomatic C. difficile carriers to new colonizations and to determine the most important epidemiological factors influencing C. difficile transmission.

Retrospective cohort study of all patients admitted to medical wards at a large tertiary care hospital in the United States in the calendar year 2008.

Data from six medical wards and published literature were used to develop a compartmental model of C. difficile transmission. Patients could be in one of five transition states in the model: resistant to colonization (R), susceptible to colonization (S), asymptomatically colonized without protection against CDI (C-), asymptomatically colonized with protection against CDI (C+), and diseased (ie, with CDI; D).

The contributions of C-, C+, and D patients to new colonizations were similar. The simulated basic reproduction number ranged from 0.55 to 1.99, with a median of 1.04. These values suggest that transmission within the ward alone from patients with CDI cannot sustain new C. difficile colonizations and therefore that the admission of colonized patients plays an important role in sustaining transmission in the ward. The epidemiological parameters that ranked as the most influential were the proportion of admitted C- patients and the transmission coefficient for asymptomatic carriers.

Our study underscores the need to further evaluate the role of asymptomatically colonized patients in C. difficile transmission in healthcare settings.

To determine the status of programs to improve antimicrobial prescribing at select US hospitals.

Cross-sectional survey.

Pharmacy and infection control staff at all 47 hospitals participating in phase 3 of Project Intensive Care Antimicrobial Resistance Epidemiology.

All 47 hospitals had some programs to improve antimicrobial use, but the practices reported varied considerably. All used a formulary, and 43 (91%) used it in conjunction with at least one of the other three antimicrobial-use policies evaluated: stop orders, restriction, and criteria-based clinical practice guidelines (CPGs). CPGs were reported most commonly (70%), followed by stop orders (60%) and restriction policies (40%). Although consultation with an infectious disease physician (70%) or pharmacist (66%) was commonly used to influence initial antimicrobial choice, few (40%) reported a system to measure compliance with these consultations.

In most hospitals surveyed, practices to improve antimicrobial use, although present, were inadequate based on recommendations in a Society for Healthcare Epidemiology of America and Infectious Disease Society of America joint position paper. There is room to improve antimicrobial-use stewardship at US hospitals.

To determine whether transfer from a long-term care facility (LTCF) is a risk factor for colonization with Klebsiella pneumoniae carbapenemase (KPC)–producing Enterobacteriaceae upon acute care hospital admission.

Microbiologic survey and nested case-control study.

Four hospitals in a metropolitan area (Chicago) with an early KPC epidemic.

Hospitalized adults.

Patients transferred from LTCFs were matched 1 : 1 to patients admitted from the community by age (± 10 years), admitting clinical service, and admission date (± 2 weeks). Rectal swab specimens were collected within 3 days after admission and tested for KPC-producing Enterobacteriaceae. Demographic and clinical information was extracted from medical records.

One hundred eighty patients from LTCFs were matched to 180 community patients. KPC-producing Enterobacteriaceae colonization was detected in 15 (8.3%) of the LTCF patients and 0 (0%) of the community patients (P<.001). Prevalence of carriage differed by LTCF subtype: 2 of 135 (1.5%) patients from skilled nursing facilities without ventilator care (SNFs) were colonized upon admission, compared to 9 of 33 (27.3%) patients from skilled nursing facilities with ventilator care (VSNFs) and 4 of 12 (33.3%) patients from long-term acute care hospitals (LTACHs; P<.001). In a multivariable logistic regression model adjusted for a propensity score that predicted LTCF subtype, patients admitted from VSNFs or LTACHs had 7.0-fold greater odds of colonization (ie, odds ratio; 95% confidence interval, 1.3–42; P = .022) with KPC-producing Enterobacteriaceae than patients from an SNF.

Patients admitted to acute care hospitals from high-acuity LTCFs (ie, VSNFs and LTACHs) were more likely to be colonized with KPC-producing Enterobacteriaceae than were patients admitted from the community. Identification of healthcare facilities with a high prevalence of colonized patients presents an opportunity for focused interventions that may aid regional control efforts.