To describe a pseudo-outbreak of Clostridium difficile infection (CDI) caused by a faulty toxin assay lot and to determine the effect of sensitivity, specificity, and repeated testing for C. difficile on perceived CDI burden, positive predictive value, and false-positive results.

Outbreak investigation and criterion standard.

Patients hospitalized at a tertiary care hospital who had at least 1 toxin assay for detection of C. difficile performed during the period from July 1, 2004, through June 30, 2006.

The run control chart method and the x2 test were used to compare CDI rates and the proportion of positive test results before, during, and after the pseudo-outbreak. The effect of repeated testing was evaluated by using 3 hypothetical models with a sample of 10,000 patients and various assay sensitivity and specificity estimates.

In November of 2005, the CDI rate at the hospital increased from 1.5 to 2.6 cases per 1,000 patient-days (P< .01), and the proportion of positive test results increased from 13.6% to 22.1% (P< .01). An investigation revealed a pseudo-outbreak caused by a faulty toxin assay lot. A decrease of only 1.2% in the specificity of the toxin assay would result in a 32% increase in perceived incidence of CDI at this institution. When calculated by use of the manufacturer's stated specificity and sensitivity and this institution's testing practices, the positive predictive value of the test decreased from 80.6% to 4.1% for patients who received 3 tests.

Specificity is as important as sensitivity when testing for CDI. False-positive CDI cases can drain hospital resources and adversely affect patients. Repeated testing for C. difficile should be performed with caution.

The prevalence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains causing bloodstream infection (BSI) has not been studied in Korea.

We sought to determine the prevalence of CA-MRSA strains among isolates recovered from patients with MRSA BSIs and to explore epidemiological changes in Korea. We also sought to evaluate clinical characteristics relevant to the development of healthcare-associated BSIs.

We prospectively collected consecutive MRSA isolates from patients with BSI at 4 hospitals from July 1 through November 30, 2007, and we also included MRSA isolates recovered from culture of blood samples collected during a previous year (October 1, 2004 through September 30, 2005) at a different hospital. Molecular typing studies were performed, including pulsed-field gel electrophoresis (PFGE), multilocus sequence typing, Staphylococcus protein A (spa) typing, and staphylococcal cassette chromosome mec (SCCmec) typing. We compared the clinical characteristics and outcomes of patients with healthcare-associated BSI due to CA-MRSA strains with those of patients with healthcare-associated BSI due to healthcare-associated MRSA (HA-MRSA) strains.

There were 76 cases of MRSA BSI, of which 4 (5.3%) were community-associated and 72 (94.7%) were healthcare-associated. Among the 72 HA-MRSA BSIs, 18 (25%) were community onset, and 54 (75%) were hospital onset. PFGE type D-ST72–spa B-SCCmec type IVA MRSA, the predominant genotype of CA-MRSA in Korea, accounted for 19 (25%) of all 76 MRSA BSIs, including 17 (23.6%) of 72 HA-MRSA BSIs and 11 (20.8%) of 53 hospital-onset HA-MRSA BSIs. Patients with healthcare-associated BSIs due to CA-MRSA strains carrying SCCmec type IVA tended to have fewer healthcare-associated risk factors, compared with patients with healthcare-associated BSIs due to HA-MRSA strains carrying other SCCmec types. The presence of a central venous catheter or other invasive device was the only independent factor differentiating patients infected with hospital-associated genotype strains from patients infected with other strains. Clinical outcomes were similar between both groups.

CA-MRSA strains are emerging as a major cause of BSI in healthcare settings in Korea. This changing epidemiology of MRSA poses a challenge to public health and infection control in hospital settings.

To determine the rates of healthcare-acquired febrile respiratory infection (HA-FRI) in Canadian pediatric hospitals and to determine the vaccination status of patients with healthcare-acquired respiratory syncytial virus (RSV) infection, influenza, or pneumococcal infection who were also eligible for immunoprophylaxis.

Prospective surveillance was conducted in 8 hospitals from January 1 to April 30, 2005. All hospitalized patients less than 18 years of age were eligible, except for patients housed in standard newborn nurseries or psychiatric units. Infection control professionals reviewed laboratory reports, conducted ward rounds, and reviewed medical records to identify case patients. Descriptive analyses were completed, as well.

A total of 96 case patients were identified; 52 (54%) were male, and 48 (50%) were aged 1 year or less. Seventy-two patients (75%) had chronic medical conditions. Respiratory viruses accounted for 72 (71%) of 101 pathogens identified, and RSV was the virus most frequently identified. Of these 96 patients, 9 (9%) died, and 3 (3%) of the deaths were related to the patient's HA-FRI. The mean incidence rate was 0.97 infections/1,000 patient-days (range, 0.29–1.50 infections/1,000 patient-days). Only 2 (15%) of 13 influenza vaccine-eligible children who acquired influenza while hospitalized were reported to have been vaccinated, but influenza vaccination status was unknown for most children. However, 4 (80%) of 5 RSV prophylaxis-eligible children who had healthcare-acquired RSV infection had received immunoprophylaxis with anti-RSV monoclonal antibody.

HA-FRI is mainly caused by viruses such as RSV, and it primarily affects children under 1 year of age and those with chronic medical conditions.

Pseudomonas aeruginosa has been increasingly recognized for its ability to cause significant hospital-associated outbreaks, particularly since the emergence of multidrug-resistant strains. Biofilm formation allows the pathogen to persist in environmental reservoirs. Thus, multiple hospital room design elements, including sink placement and design, can impact nosocomial transmission of P. aeruginosa and other pathogens.

From December 2004 through March 2006, 36 patients exposed to the intensive care unit or transplant units of a tertiary care hospital were infected with a multidrug-resistant strain of P. aeruginosa. All phenotypically similar isolates were examined for genetic relatedness by means of pulsed-field gel electrophoresis. Clinical characteristics of the affected patients were collected, and a detailed epidemiological and environmental investigation of potential sources was carried out.

Seventeen of the infected patients died within 3 months; for 12 (71%) of these patients, infection with the outbreak organism contributed to or directly caused death. The source of the outbreak was traced to hand hygiene sink drains, where biofilms containing viable organisms were found. Testing by use of a commercial fluorescent marker demonstrated that when the sink was used for handwashing, drain contents splashed at least 1 meter from the sink. Various attempts were made to disinfect the drains, but it was only when the sinks were renovated to prevent splashing onto surrounding areas that the outbreak was terminated.

This report highlights the importance of biofilms and of sink and patient room design in the propagation of an outbreak and suggests some strategies to reduce the risks associated with hospital sinks.

To compare the effects of different skin preparation solutions on surgical-site infection rates.

Three skin preparations were compared by means of a sequential implementation Design. Each agent was adopted as the preferred modality for a 6-month period for all general surgery cases. Period 1 used a povidone-iodine scrub-paint combination (Betadine) with an isopropyl alcohol application between these steps, period 2 used 2% Chlorhexidine and 70% isopropyl alcohol (ChloraPrep), and period 3 used iodine povacrylex in isopropyl alcohol (DuraPrep). Surgical-site infections were tracked for 30 days as part of ongoing data collection for the National Surgical Quality Improvement Project initiative. The primary outcome was the overall rate of surgical-site infection by 6-month period performed in an intent-to-treat manner.

Single large academic medical center.

All adult general surgery patients.

The study comprised 3,209 operations. The lowest infection rate was seen in period 3, with iodine povacrylex in isopropyl alcohol as the preferred preparation method (3.9%, compared with 6.4% for period 1 and 7.1% for period 2; P = .002). In subgroup analysis, no difference in outcomes was seen between patients prepared with povidone-iodine scrub-paint and those prepared with iodine povacrylex in isopropyl alcohol, but patients in both these groups had significantly lower surgical-site infection rates, compared with rates for patients prepared with 2% Chlorhexidine and 70% isopropyl alcohol (4.8% vs 8.2%; P = .001).

Skin preparation solution is an important factor in the prevention of surgical-site infections. Iodophor-based compounds may be superior to Chlorhexidine for this purpose in general surgery patients.

The incidence and severity of Clostridium difficile infection (CDI) are increasing, and previously described interventions for controlling the spread of CDI are not easily generalized to multiple healthcare institutions.

We tested prevention and treatment bundles to decrease the incidence of CDI and the mortality associated with CDI at our hospital.

Observational before-after study of adult patients admitted to a tertiary care, university-affiliated hospital during the period from January 2004 through December 2008.

In January 2006, we launched an educational campaign and introduced a prevention bundle—a series of specific processes aimed at preventing the transmission of C. difficile among hospitalized patients, including enhanced isolation practices, laboratory notification procedures, and steps coordinating infection control and environmental services activities. In April 2006, we implemented a treatment bundle—a set of hospital-wide treatment practices aimed at minimizing the risk of serious CDI complications. We tracked quarterly incidence rates and case-fatality rates for healthcare-associated CDI cases at our hospital. Our main outcome was the healthcare-associated CDI incidence rate, measured as the number of healthcare-associated cases of CDI per 1,000 patient-days.

We followed patients for a total of 1,047,849 patient-days. The healthcare-associated CDI incidence rates fell from an average of 1.10 cases per 1,000 patient-days before intervention to 0.66 cases per 1,000 patient-days after intervention. This statistically significant decrease amounts to a 40% reduction in incidence after the intervention.

Our intervention was successful in reducing the incidence of CDI at our hospital. On the basis of our experience, we propose the use of a checklist of hospital interventions to decrease the incidence of healthcare-associated CDI.

To ascertain whether cystic fibrosis (CF) patients are colonized or infected with unique or multiple strains of Stenotrophomonas maltophilia; to understand whether some strains colonize or infect more than 1 patient, indicating clonal spread; and to explore the molecular heterogeneity of hospital water isolates and their correlation with clinical isolates.

The regional CF center of Policlinico “Umberto I” of Rome, Italy.

The study was carried out on a random sample of S. maltophilia isolates (n = 110) collected from CF patients (n = 50) during the period 2002–2005 and on 24 water isolates obtained during a monitoring program in the first 6 months of 2005. Home environmental samplings were not performed. All isolates, which were recovered from cultures of specimens obtained in both inpatient and outpatient settings, were genotyped with DNA macrorestriction analysis with the restriction enzyme Xbal and pulsed-field gel electrophoresis.

One-third of the patients with repeated episodes of S. maltophilia infection or colonization hosted more than 1 strain. A potential transmission, defined as the isolation of the same strain in 2 or more patients, occurred 5 times, showing a frequency of potential transmission episodes slightly higher than previously reported. Water, taps, and sinks of the different rooms of the CF center tended to be persistently colonized with the same strain of S. maltophilia, with no correlation between clinical and water-associated isolates.

The study does not provide sufficient data to conclude definitively that isolation of colonized or infected CF patients and control of hospital water systems contamination would be beneficial infection control measures. Epidemiologic analytical studies that correlate the presence of S. maltophilia with clinical outcomes are strongly needed.

We describe our experience using a real-time polymerase chain reaction (PCR) assay for methicillin-resistant Staphylococcus aureus (MRSA) during a period of active surveillance in the neonatal intensive care unit (NICU) from March 2007 until November 2007.

TO compare PCR with bacterial culture methods and find the screening algorithm that most successfully ensures appropriate isolation of colonized patients.

Patients in the NICU were screened for MRSA on admission and weekly thereafter until discharge. Healthcare workers (HCWs) were also screened as part of an outbreak investigation. A total of 599 individuals were screened for MRSA with both a PCR assay and selective bacterial culture. Strain typing was performed on all MRSA isolates to determine clonal relatedness.

Twenty-one of 435 infants (4.8%) screened positive for MRSA with the PCR assay. Only 11 patients (52.4%) had concomitant bacterial cultures positive for MRSA. Compared to bacterial culture, the PCR assay had a sensitivity of 100% and a specificity of 97.6%, with a positive predictive value (PPV) of 52.4%. Infants that tested positive for MRSA by both culture and PCR were more likely to have a positive PCR assay result when retested than were those who tested positive by PCR alone (80% vs 20%; P = .02). Strain typing of MRSA isolates identified a common clone in only 2 colonized infants.

Our data show that, in our neonatal population, the reproducibility of PCR assay results for culture-negative patients was low compared with the reproducibility of results for culture-positive Patients. Furthermore, the low PPV suggests that for nearly half of individuals who were PCR-positive, the result was falsely positive, which argues against the use of PCR assays alone for MRSA screening in the NICU.

To determine the relationship between indequate antimicrobial prophylaxis and development of gram-negative bacterial (GNB) surgical site infection (SSI).

Retrospective case-control study.

A 369-bed acute care community hospital in Durham, North Carolina.

Case patients were defined as patients who developed a GNB SSI after undergoing a surgical procedure during the period from January 1, 1998, through January 1, 2007. Control patients were uninfected patients who underwent surgery during the same study period and were matched to case patients by surgeon and type of procedure. Both patient groups were selected on the basis of prospectively collected data on patients who underwent surgery.

Patient data were collected from patient medical records. Multivariable analysis was performed using logistic regression with backward selection, to identify variables independently associated with GNB SSI.

Case patients were similar to control patients with respect to demographics and comorbid conditions, but were older (P = .04), more obese (P = .03), and more likely to have diabetes mellitus (P = .03). Inappropriate timing of antimicrobial prophylaxis was the predominant reason that prophylaxis was deemed inadequate for both patient groups (59.1% of case patients vs 64.0% of control patients; P = .56). Case patients who had a history of allergic reactions to antimicrobial prophylaxis were significantly less likely to receive antimicrobial prophylaxis in a timely manner (P = .03). Variables independently associated with GNB SSI in multivariable analysis included urinary catheterization before surgery (odds ratio [OR], 3.74 [95% confidence interval {CI}, 1.11-12.62), diabetes mellitus (OR, 2.25 [95% CI, 1.02-4.94]), and an American Society of Anesthesiologists score greater than 2 (OR, 2.14 [95% CI, 1.13-4.06]).

A β-lactam allergy was not associated with increased risk for GNB SSI. Further studies, using patient data from larger hospital databases, are needed to examine the relationship between use of urinary catheter before surgery and risk of GNB SSI.

Although hospital-acquired infections appear to be a growing threat to the survival of newborns in the developing world, the epidemiology of this problem remains poorly characterized.

During a 10-month period, we conducted prospective longitudinal surveillance for colonization and bloodstream infection caused by gram-negative rods among all infants hospitalized in the 2 largest neonatal intensive care units in Manila, the Philippines. We determined antibiotic susceptibilities and calculated adjusted odds ratios for risk factors for bacteremia by means of multivariate logistic regression.

Of 1,831 neonates enrolled during a 10-month period, 1,017 (55.5%) became newly colonized and 358 (19.6%) became bacteremic with a drug-resistant gram-negative rod, most commonly Klebsiella species, Enterobacter species, Acinetobacter species, and Pseudomonas aeruginosa. Of the invasive isolates, 20% were resistant to imipenem, 41% to trimethoprim-sulfamethoxazole, 52% to amikacin, 63% to ampicillin-sulbactam, 67% to ceftazidime, and 80% to tobramycin. The factors significantly associated with an increased risk of bacteremia were mechanical ventilation and prematurity. Additionally, colonization with a drug-resistant gram-negative rod was an independent risk factor for bacteremia (odds ratio, 1.4 [95% confidence interval, 1.0-1.9]).

Colonization with a drug-resistant gram-negative rod was an independent risk factor for sepsis. If our data are typical, the unusually high intensity of colonization pressure and disease caused by multidrug-resistant gram-negative rods at these 2 neonatal intensive care units indicates an emerging healthcare crisis in the developing world. Improved infection control methods are therefore critically needed in developing countries.

To determine the impact of antibiotic consumption and alcohol-based hand disinfection on the incidences of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection and Clostridium difficile infection (CDI).

Two multivariate time-series analyses were performed that used as dependent variables the monthly incidences of nosocomial MRSA infection and CDI at the Freiburg University Medical Center during the period January 2003 through October 2007. The volume of alcohol-based hand rub solution used per month was quantified in liters per 1,000 patient-days. Antibiotic consumption was calculated in terms of the number of defined daily doses per 1,000 patient-days per month.

The use of alcohol-based hand rub was found to have a significant impact on the incidence of nosocomial MRSA infection (P<.001). The multivariate analysis (R2 = 0.66) showed that a higher volume of use of alcohol-based hand rub was associated with a lower incidence of nosocomial MRSA infection. Conversely, a higher level of consumption of selected antimicrobial agents was associated with a higher incidence of nosocomial MRSA infection. This analysis showed this relationship was the same for the use of second-generation cephalosporins (P = .023), third-generation cephalosporins (P = .05), fluoroquinolones (P = .01), and lincosamides (P = .05). The multivariate analysis (R2 = 0.55) showed that a higher level of consumption of third-generation cephalosporins (P = .008), fluoroquinolones (P = .084), and/or macrolides (P = .007) was associated with a higher incidence of CDI. A correlation with use of alcohol-based hand rub was not detected.

In 2 multivariate time-series analyses, we were able to show the impact of hand hygiene and antibiotic use on the incidence of nosocomial MRSA infection, but we found no association between hand hygiene and incidence of CDI.

To conduct a cost-effectiveness analysis of the economic outcomes of ventilator-associated pneumonia (VAP) prevention associated with silver-coated endotracheal tubes versus uncoated endotracheal tubes.

We used a simple decision model based on a hypothetical 1,000-patient cohort intubated with silver-coated or uncoated endotracheal tubes. The primary end point was marginal hospital savings per case of VAP prevented (savings from using silver-coated endotracheal tubes minus acquisition cost divided by number of VAP cases prevented).

We followed each branch of the decision model to VAP or no VAP and conducted Monte Carlo simulations and sensitivity analyses. Inputs for VAP incidence, relative risk reduction, and hospital costs were derived from publicly available sources. Relative risk reduction was derived from the pivotal study of the silver-coated endotracheal tube.

In the base-case analysis, we reduced the pivotal study relative risk in incidence of microbiologically confirmed VAP in patients intubated ≥24 hours from 35.9% to 24%. Thus, 23 of 97 expected cases of VAP could be prevented with silver-coated endotracheal tubes. The savings per case of VAP prevented was $12,840 in the base case, with assumed marginal VAP cost of $16,620 and costs of $90.00 for coated and $2.00 for uncoated endotracheal tubes. Estimates were most sensitive to assumptions regarding VAP cost and relative risk reduction with silver-coated endotracheal tubes. Nonetheless, in multivariate sensitivity analyses, the silver-coated endotracheal tubes yielded persistent savings (95% confidence interval, $9,630-$16,356) per case of VAP prevented. With other base-case inputs held constant, breakeven cost for silver-coated endotracheal tubes was $388.

The silver-coated endotracheal tube represents a strategy for preventing VAP that may yield hospital savings.

Healthcare-associated infections (HAIs) are an important cause of morbidity and mortality worldwide. During the period from 2002 through 2004, a group of Italian hospitals was recruited to conduct HAI point-prevalence surveys.

Three point-prevalence surveys.

A total of 9,609 patients were surveyed.

The overall frequency of HAI was 6.7% (645 infections among the 9,609 surveyed patients). The most frequent HAIs were lower respiratory tract infections, which accounted for 35.8% (231 of 645 HAIs) of all HAIs, followed by urinary tract infections (152 [23.6%] of 645 HAIs), bloodstream infections (90 [14.0%] of 645 HAIs), and surgical site infections (79 [12.2%] of 645 HAIs). In both multivariate and univariate analysis, invasive procedures, duration of stay, chemotherapy, trauma, coma, and the location of the hospital were all factors statistically significantly associated with the occurrence of an HAL Enterobacteriaceae were the most common isolates recovered in medical and surgical wards, whereas gram-negative aerobic bacilli were the most common isolates recovered in intensive care units. Approximately one-half of all of the patients surveyed were receiving antibiotics at the time of our study; the most used antibiotic classes were fluoroquinolones in medical wards, cephalosporins in surgical wards, and penicillins and glycopeptides in intensive care units.

Our study emphasizes the need for implementing further HAI surveillance to provide the National Health System with proper tools to prevent and manage infection in hospitalized patients.

A cluster of patients with respiratory cultures positive for Pseudomonas aeruginosa with a unique antibiogram was observed during June and July 2007 at a 1,000-bed urban teaching hospital in Atlanta, Georgia. These P. aeruginosa isolates were recovered from bronchoscopically obtained specimens.

A cross-sectional study was performed to assess whether the cluster was associated with exposure to a particular bronchoscope (B1); cultures from specimens from the bronchoscopes and the environment were obtained, and the P. aeruginosa isolate type was determined using pulsed-field gel electrophoresis (PFGE). Records of patients exposed to B1 during the cluster period were reviewed.

Twelve patients with a culture positive for P. aeruginosa with the unique susceptibility pattern were identified in June-July 2007. No cases were documented from March 1 through May 31, 2007. Culture specimens obtained from B1 after high-level disinfection revealed P. aeruginosa, prompting removal of B1 from service on July 23, 2007. No cases occurred after that date. Eleven (55%) of 20 patients who were exposed to Bl during the cluster period had a culture positive for P. aeruginosa, compared with 1 (2%) of 53 patients who were exposed to other bronchoscopes (P < .001). PFGE patterns for P. aeruginosa isolates obtained from case patients and from B1 were identical. An engineering evaluation of B1 documented several internal damages. Two (10.5%) of 19 patients exposed to Bl during the cluster period may have developed P. aeruginosa infection following exposure to B1.

An outbreak or pseudo-outbreak of P. aeruginosa infection occurred in association with use of a damaged bronchoscope. Periodic engineering maintenance may be needed to prevent bronchoscope contamination that is resistant to high-level disinfection.

The International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code for Clostridium difficile infection (CDI) is used for surveillance of CDI. However, the ICD-9-CM code alone cannot separate nosocomial cases from cases acquired outside the institution. The purpose of this study was to determine whether combining the ICD-9-CM code with medication treatment data for CDI in hospitalized patients could enable us to distinguish between patients with nosocomial CDI and patients who were admitted with CDI. The primary objective was to compare the sensitivity, specificity, and predictive value of using the combination of ICD-9-CM code for CDI and CDI treatment records to identify cases of nosocomial CDI with the sensitivity, specificity, and predictive value of using the ICD-9-CM code alone.

Validation sample cross-sectional study.

Academic health center.

Administrative claims data from July 1, 2004, to June 30, 2005, were queried to identify adults discharged with an ICD-9-CM code for CDI and to find documentation of CDI therapy with oral vancomycin or metronidazole. Laboratory and medical records were queried to identify symptomatic CDI toxin-positive adult patients with nosocomial CDI and were compared with records of patients whose cases were predicted to be nosocomial by means of ICD-9-CM code and CDI therapy data.

Of 23,920 adult patients discharged from the hospital, 62 had nosocomial CDI according to symptoms and toxin assay. The sensitivity of the ICD-9-CM code alone for identifying nosocomial CDI was 96.8%, the specificity was 99.6%, the positive predictive value was 40.8%, and the negative predictive value was 100%. When CDI drug therapy was included with the ICD-9-CM code, the sensitivity ranged from 58.1% to 85.5%, specificity was virtually unchanged, and the range in positive predictive value was 37.9%–80.0%.

Combining the ICD-9-CM code for CDI with drug therapy information increased the positive predictive value for nosocomial CDI but decreased the sensitivity.

To investigate a large outbreak of scabies in an intensive care unit of a university hospital and an affiliated rehabilitation center, and to establish effective control measures to prevent further transmission.

Outbreak investigation.

The intensive care unit of a 750-bed university hospital and an affiliated 92-bed rehabilitation center.

All exposed individuals were screened by a senior staff dermatologist. Scabies was diagnosed on the basis of (1) identification of mites by skin scraping, (2) identification of mites by dermoscopy, or (3) clinical examination of patients without history of prior treatment for typical burrows. During a follow-up period of 6 months, the attack rate was calculated as the number of symptomatic individuals divided by the total number of exposed individuals.

All exposed healthcare workers (HCWs) and their household members underwent preemptive treatment. Initially, the most effective registered drug in Switzerland (ie, topical lindane) was prescribed, but this prescribption was switched to topical permethrin or systemic ivermectin as a result of the progression of the outbreak. Individuals with any signs or symptoms of scabies underwent dermatological examination.

Within 7 months, 19 cases of scabies were diagnosed, 6 in children with a mean age of 3.1 years after exposure to the index patient with HIV and crusted scabies. A total of 1,640 exposed individuals underwent preemptive treatment. The highest attack rate of 26%–32% was observed among HCWs involved in the care of the index patient. A too-restricted definition of individuals at risk, non-compliance with treatment, and the limited effectiveness of lindane likely led to treatment failure, relapse, and reinfestation within families.

Crusted scabies resulted in high attack rates among HCWs and household contacts. Timely institution of hygienic precautions with close monitoring and widespread, simultaneous scabicide treatment of all exposed individuals are essential for control of an outbreak.

To determine the attributable (direct) mortality and morbidity caused by carbapenem-resistant Klebsiella pneumoniae bacteremia.

A matched retrospective, historical cohort design, using a stepwise procedure to stringendy match the best control subjects to the best case subjects.

A 1,000-bed tertiary-care university teaching hospital.

Case subjects were defined as adult patients with carbapenem-resistant K. pneumoniae bacteremia during the period from October 2005 through October 2008. Control subjects were defined as patients who were very similar to case subjects except that they did not have bacteremia.

Matching potential control subjects to case subjects was performed at a 1:1 ratio using a computerized record system. The criteria used included same hospitalization period, similar Charlson comorbidity index, same underlying disease, same age within 10 years, and same sex. Demographic and clinical characteristics were collected from medical records.

During the study period, 319 patients developed an infection due to carbapenem-resistant K. pneumoniae. Of these 319 patients, 39 (12.2%) developed a bloodstream infection, for an overall rate of 0.59 episodes of carbapenem-resistant K. pneumoniae bacteremia per 10,000 patient-days. We excluded 7 patients from our study, leaving a total of 32 case subjects in our cohort. Case subjects were significandy more likely than control subjects (n = 32) to require care in an intensive care unit (12 case subjects [37.5%] vs 3 control subjects [9.4%]), ventilator support (17 case subjects [53.1%] vs 8 control subjects [25%]), and use of a central venous catheter (19 case subjects [59.4%] vs 9 control subjects [28.1%]). For case subjects, the crude mortality rate was 71.9% (ie, 23 of the 32 case subjects died); for control subjects, the crude mortality rate was 21.9% (ie, 7 of the 32 control subjects died) (P < .001. For case subjects, the attributable mortality was 50% (95% confidence interval [CI], 15.3%-98.6%). A mortality risk ratio of 3.3 (95% CI, 2.9-28.5) was found for case subjects with carbapenem-resistant K. pneumoniae bacteremia.

Patients with carbapenem-resistant K. pneumoniae require more intensive and invasive care. We have shown that the crude and attributable mortality rates associated with carbapenem-resistant K. pneumoniae bacteremia were striking.

To assess the impact of an institution-wide infection control education program on the rate of transmission of methicillin-resistant Staphylococcus aureus (MRSA).

Before-and-after study.

A 472-bed, urban, university-affiliated hospital.

During the period March-May 2004, all hospital staff completed a mandatory infection control education program, including the receipt of hospital-specific MRSA data and case-based practice with additional precautions.

The rate of nosocomial MRSA acquisition was calculated as the number of cases of nosocomial MRSA acquisition per 100 days that a person with MRSA colonization or infection detected at admission is present in the hospital (“admission MRSA” exposure-days) for 3 time periods: June 2002-February 2003 (before the Toronto outbreak of severe acute respiratory syndrome [SARS]), June 2003-February 2004 (after the outbreak of SARS), and June 2004-February 2005 (after education). A case of nosocomial acquisition of MRSA colonization or infection represented a patient first identified as colonized or infected more than 72 hours after admission or at admission after a previous hospitalization.

The rate of nosocomial acquisition of MRSA colonization or infection was 8.8 cases per 100 admission MRSA exposure-days for the period before SARS, 3.8 cases per 100 admission MRSA exposure-days for the period after SARS (P < .001 for before SARS vs after SARS), and 1.9 cases per 100 admission MRSA exposure-days for the period after education (P = .02 for after education vs before education). The volume of alcohol-based handrub purchased was apparently stable, with 4,010 L during fiscal year 2003-2004 (April 2003-March 2004) compared with 3,780 L during fiscal year 2004—2005. The observed rate of compliance with hand washing did not change significantly (40.9% during education vs 44.2% after education; P = .23). The total number of patients screened for MRSA colonization was not different in the 3 periods.

The rate of nosocomial acquisition of MRSA colonization or infection decreased after SARS and was further reduced in association with a hospital-wide education program.

To assess the effect of enhanced infection control measures with screening for gastrointestinal colonization on limiting the spread of carbapenem-resistant Klebsiella pneumoniae in a New York City hospital endemic for this pathogen.

Retrospective observational study with pre- and postinterventional phases.

Beginning in 2006, a comprehensive infection control program was instituted in a 10-bed medical and surgical intensive care unit at a university-based medical center. In addition to being placed in contact isolation, all patients colonized or infected with carbapenem-resistant gram-negative bacilli, vancomycin-resistant Enterococcus, or methicillin-resistant Staphylococcus aureus were cohorted to one end of the unit. Improved decontamination of hands and environmental surfaces was encouraged. In addition, routine rectal surveillance cultures were screened for the presence of carbapenem-resistant pathogens. The number of patients per quarter with clinical cultures positive for carbapenem-resistant K. pneumoniae was compared during the approximately 2-year periods before and after the intervention.

The mean number ( ± SD) of new patients per 1,000 patient-days per quarter with cultures yielding carbapenem-resistant K. pneumoniae decreased from 9.7 ± 2.2 before the intervention to 3.7 ± 1.6 after the intervention (P< .001 ). There was no change in the mean number of patient-days or the mean number of patients per quarter with cultures yielding methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, or carbapenem-resistant Acinetobacter baumannii or Pseudomonas aeruginosa after the intervention. There was no association between antibiotic usage patterns and carbapenem-resistant K. pneumoniae.

The comprehensive intervention that combined intensified infection control measures with routine rectal surveillance cultures was helpful in reducing the incidence of carbapenem-resistant K. pneumoniae in an intensive care unit where strains producing the carbapenemase KPC were endemic.