To assess nosocomial infection (NI) as a risk factor for death and to estimate the population-attributable risk of death from NI.

A prospective cohort study of patients with and without NI.

Nîmes University Hospital, Nîmes, France.

Patients were recruited from May 7, 2001, to January 10, 2003. Patients in acute care and long-term care units who had NI were enrolled, and patients without NI were randomly selected and matched with patients with NI for age, sex, type of care (acute care vs. long-term care) and length of stay in hospital at study inclusion.

Vital status within 60 days after study inclusion was assessed. We used conditional logistic regression to estimate the relative death risk from NI after adjusting for comorbidities, severity of the underlying disease, and all other confounding factors. The adjusted population-attributable risk was assessed using the Mantel-Haenszel method.

We recruited 1,914 patients with NI and 5,172 patients without NI. The median age of the patients with NI was 73 years; 1,045 (54.6%) were female. NI was associated with death within 60 days (adjusted odds ratio, 1.7 [95% confidence interval {CI}, 1.4—;2.2]; P-C.001). The adjusted population-attributable risk of death for all sites of infection was 1.7% (95% CI, 1.4-2.1). If we consider the NI incidence to be 3%-6% in French hospitals, the population-attributable risk of death from NI would range from 2.1% (95% CI, 1.7%-2.5%) to 4.0% (95% CI, 3.3%-4.9%).

In this study, NI appeared to have a significant impact on mortality. Multicenter studies will be needed to confirm these results.

To quantify the clinical impact of methicillin-resistance in Staphylococcus aureus causing infection complicated by bacteremia in adult patients, while controlling for the severity of patients' underlying illnesses.

Retrospective cohort study from October 1, 1995, through December 31, 2003.

A total of 438 patients with S. aureus infection complicated by bacteremia from a single Veterans Affairs healthcare system.

We found that 193 (44%) of the 438 patients had methicillin-resistant S. aureus (MRSA) infection and 114 (26%) died of causes attributable to S. aureus infection within 90 days after the infection was identified. Patients with MRSA infection had a higher mortality risk, compared with patients with methicillin-susceptible S. aureus (MSSA) infections (relative risk, 1.7 [95% confidence interval, 1.3-2.4]; P < .01), except for patients with pneumonia (relative risk, 0.7 [95% confidence interval, 0.4-1.3]). Patients with MRSA infections were significantly older (P < .01), had more underlying diseases (P = .02), and were more likely to have severe sepsis in response to their infection (P < .01) compared with patients with MSSA bacteremia. Patients who died within 90 days after S. aureus infection was identified were significantly older (P < .01) and more likely to have severe sepsis (P < .01) and pneumonia (P = .01), compared with patients who survived. After adjusting for age as a confounder, comorbidities, and pneumonia as an effect modifier, S. aureus infection-related mortality remained significantly higher in patients with MRSA infection than in those with MSSA infection, among those without pneumonia (hazard ratio, 1.8 [95% confidence interval, 1.2-3.0]); P < .01.

The results of this study suggest that patients with MRSA infections other than pneumonia have a higher mortality risk than patients with MSSA infections other than pneumonia, independent of the severity of patients' underlying illnesses.

To estimate the independent effect of a single lower respiratory tract infection, urinary tract infection, or other healthcare-acquired infection on length-of-stay and variable costs and to demonstrate the bias from omitted variables that is present in previous estimates.

Prospective cohort study.

A tertiary care referral hospital and regional district hospital in southeast Queensland, Australia.

Adults aged 18 years or older with a minimum inpatient stay of 1 night who were admitted to selected clinical specialities.

Urinary tract infection was not associated with an increase in length of hospital stay or variable costs. Lower respiratory tract infection was associated with an increase of 2.58 days in the hospital and variable costs of AU$24, whereas other types of infection were associated with an increased length of stay of 2.61 days but not with variable costs. Many other factors were found to be associated with increased length of stay and variable costs alongside healthcare-acquired infection. The exclusion of these variables caused a positive bias in the estimates of the costs of healthcare-acquired infection.

The existing literature may overstate the costs of healthcare-acquired infection because of bias, and the existing estimates of excess costs may not make intuitive sense to clinicians and policy makers. Accurate estimates of the costs of healthcare-acquired infection should be made and used in appropriately designed decision-analytic economic models (ie, cost-effectiveness models) that will make valid and believable predictions of the economic value of increased infection control.

To determine the attributable mortality and outcome of nosocomial Acinetobacter bacteremia.

Matched, retrospective cohort study.

Large, university-based, tertiary care center.

Of 219 patients with nosocomial Acinetobacter bacteremia identified by prospective surveillance during a 3-year period, 52 met the criteria for the study and were matched to a control patient by age, sex, primary and secondary diagnosis, operative procedures, and date of admission.

A 100% success rate was achieved in the proportion of case patients and control patients matched for the compared criteria, except for major operative procedures (88%) and the presence of an important secondary underlying disease (54.5%). Twenty-nine (55.7%) of the case patients died, compared with 10 (19.2%) of the control patients (P < .001). The attributable mortality was 36.5% (95% CI, 27%-46%) and the risk ratio for death was 2.9 (95% CI, 1.58-5.32). In a multivariate survival analysis, older age, mechanical ventilation, renal failure, and Acinetobacter bacteremia (hazard ratio [HR], 4.41; 95% confidence interval [CI], 1.97-9.87; P < .001) were found to be independent predictors of mortality. There was a trend for a longer median duration of hospitalization among case patients, compared with control patients (11.5 vs. 6.5 days; P = .06). Three isolates were resistant to all but 1 antibiotic tested (colistin), and 45 isolates (86.5%) were resistant to 4 or more different antibiotic classes.

When adjusted for risk-exposure time and severity of disease at admission, nosocomial Acinetobacter bacteremia is associated with mortality in excess of that caused by the underlying diseases alone.

To determine the prevalence, risk factors, and outcomes of nosocomial infection due to antimicrobial resistant bacteria in patients treated in the pediatric intensive care unit (PICU).

Nested case-cohort study. Patient data were collected prospectively, and antimicrobial susceptibility data were abstracted retrospectively.

A large pediatric teaching hospital.

All PICU patients admitted from September 1, 1999, to September 1, 2001, unless they died within 24 hours after PICU admission, were 18 years old or older, or were neonatal intensive care unit patients receiving extracorporeal membrane oxygenation.

A total of 135 patients with more than 1 nosocomial bacterial infection were analyzed; 52% were male, 75% were white, the mean Pediatric Risk of Mortality score was 10.5, and the mean age was 3.5 years. Of these patients, 37 (27%) had nosocomial infections due to antibiotic-resistant organisms. In univariate analysis, transplantation (odds ratio [OR], 2.83 [95% confidence interval (CI), 1.05-7.66]) and preexisting lung disease (OR, 2.63 [95% CI, 1.18-5.88]) were associated with nosocomial infections due to antibiotic-resistant organisms. Age, Pediatric Risk of Mortality score at admission, length of hospital stay before infection, and other underlying conditions were not associated with infections due to antibiotic-resistant organisms. Patients infected with antibiotic-resistant organisms had greater mean PICU lengths of stay after infection, compared with patients infected with antibiotic-susceptible organisms (22.9 vs 12.8 days; P = .004), and higher crude mortality rates (OR, 2.40 [95% CI, 1.03-5.61]).

Identifiable risk factors exist for nosocomial infections due to antibiotic-resistant organisms. In univariate analysis, infections due to antibiotic-resistant bacteria are associated with increased length of stay in the PICU after onset of infection and increased mortality.

To determine the incidence of ventilator-associated pneumonia (VAP) among intensive care unit (ICU) patients in Japan and to assess the impact of VAP on patient outcomes, including mortality, length of stay, and duration of mechanical ventilation.

Multicenter cohort study.

Twenty-eight ICUs in multidisciplinary Japanese hospitals with more than 200 beds.

A total of 21,909 patients 16 years or older who were admitted to an ICU between June 2002 and June 2004, stayed in the ICU for 24 to 1,000 hours, and were not transferred to another ICU.

The overall infection rates for nosocomial pneumonia and VAP were 6.5 cases per 1,000 patient-days and 12.6 cases per 1,000 ventilator-days, respectively. The standardized mortality rates for the patients with VAP was 1.3 (95% confidence interval [CI], 1.1-1.6): 1.1 (95% CI, 0.9-1.4) for the cases due to drug-susceptible pathogens and 1.5 (95% CI, 1.1-1.9) for the cases due to drug-resistant pathogens. After adjusting for Acute Physiology and Chronic Health Evaluation II score, the mean length of stay for the patients with VAP caused by drug-susceptible pathogens (15.2 days [95% CI, 14.6-15.8]) and by drug-resistant pathogens (17.8 days [95% CI, 17.0-18.6]) was significantly longer than that in the patients without nosocomial infection (6.8 days [95% CI, 6.7-6.9]). The mean duration of mechanical ventilation in the patients with VAP caused by drug-susceptible pathogens (12.0 days [95% CI, 11.5-12.5]) and drug-resistant pathogens (14.1 days [95% CI, 13.5-14.8]) was significantly longer than that in the patients without nosocomial infection (4.7 days [95% CI, 4.6-4:8]).

The incidence of VAP is substantial among ICU patients in Japan. The potential impact of VAP on patient outcomes emphasizes the importance of preventive measures against VAP, especially for VAP caused by drug-resistant pathogens.

To investigate trends in ventilator-associated pneumonia (VAP) rates during participation in the German nosocomial infection surveillance system (Krankenhaus-Infektions-Surveillance-System [KISS]).

A total of 71 ICUs that began participating in KISS in 1999 or later and continued participation for at least 36 months were selected. Beginning with the first month of participation, the pooled mean rate of VAP in the ICUs was calculated for each year of participation. The incidence densities for the 3 years of participation were compared using the Pearson x2 test. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated. VAP rates were calculated for each ICU and year of participation, and rates for years 1 and 3 were compared using the Wilcoxon test for paired samples.

Twenty-nine medical-surgical, 18 medical, 20 surgical, 2 neurosurgical, and 2 pediatric ICUs met the selection criteria. Surveillance data were available on 181,275 patients, for whom there were 613,098 patient-days and 224,138 ventilator-days. A total of 2,043 cases of VAP were reported. The ICUs had a pooled VAP rate of 10.5 cases per 1,000 ventilator-days during year 1 of KISS surveillance. In year 2, the rate decreased by 19%, to 8.7 cases per 1,000 ventilator-days (RR, 0.81 [95% CI, 0.73-0.90]). In year 3, the rate decreased by 24% from year 1, to 8.0 cases per 1,000 ventilator-days (RR, 0.76; 95% CI, 0.68-0.85). Both results were significant (P < .001 by the Pearson x2 test). Comparison of the VAP rates of the ICUs did not show a significant difference between years 1 and 3 of KISS participation.

Surveillance was associated with a significant reduction in the pooled rate of VAP during years 1-3 of KISS participation.

To assess the risk-adjusted incidence and predictors of surgical site infections (SSIs).

Prospective, multicenter, observational cohort study.

Seven surgical departments at 3 urban academic hospitals in St. Petersburg, Russian Federation.

All patients had surgery performed between January 15 and May 12, 2000. A total of 1,453 surgical procedures were followed up. Medical records were unavailable for less than 3% of all patients; patients were not excluded for any other reason. The mean patient age was 49.3 years, 61% were female, and 34% had an American Society of Anesthesiologists physical status classification (hereafter, “ASA classification”) of at least 3. Surgery for 45% of the patients was emergent.

In all, 138 patients (9.5%) developed SSI, for a rate that was approximately 3.5 times the risk-stratified rates in the United States. Male sex (odds ratio [OR], 1.54), ASA classifications of 3 (OR, 3.7) or 4 (OR, 5.0), longer duration of surgery (OR, 2.2), and wound classes of 3 (OR, 5.5) or 4 (OR, 14.3) were associated with increased SSI risk in multivariate analysis. Endoscopic surgery was associated with a lower risk of SSI (OR, 0.23). Antibiotic prophylaxis was used in 0%-33% of operations, and 69% of uninfected patients received antibiotics after the operation.

The SSI rates are significantly higher than previously reported. Although this finding may be attributable to inadequate antibiotic prophylaxis, local infection control and surgical practices may also be contributors. Use of antibiotic prophylaxis should be encouraged and the effect of local practices further investigated. Active SSI surveillance should be expanded to other parts of the Russian Federation.

To describe the prevalence of Staphylococcus warneri on the hands of nurses and the clinical relevance of this organism among neonates in the neonatal intensive care unit (NICU).

Prospective cohort study that examined the microbial flora on the hands of nurses and clinical isolates recovered from neonates during a 23-month period (March 1, 2001, through January 31, 2003).

Two high-risk NICUs in New York City.

All neonates hospitalized in the NICUs for more than 24 hours and all full-time nurses from the same NICUs who volunteered to participate.

At baseline and then every 3 months, samples for culture were obtained from each nurse's cleaned dominant hand. Pulsed-field electrophoresis compared S. warneri isolates from neonates and staff.

Samples for culture (n = 834) were obtained from the hands of 119 nurses; 520 (44%) of the 1,195 isolates of coagulase-negative staphylococci recovered were identified as S. warneri. Of the 647 clinically relevant isolates recovered from neonates, 17 (8%) of the 202 isolates that were identified to species level were S. warneri. Pulsed-field electrophoresis revealed a common strain of S. warneri that was shared among the nurses and neonates. Furthermore, 117 (23%) of 520 S. warneri isolates from nurses' hands had minimum inhibitory concentrations for vancomycin of 4 μg/mL, which indicate decreasing susceptibility.

Our findings that S. warneri can be pathogenic in neonates, is a predominant species of coagulase-negative staphylococci cultured from the hands of nurses, and has decreased vancomycin susceptibility underscore the importance of continued surveillance for vancomycin resistance and pathogenicity in pediatric care settings.

To determine risk factors and outcomes associated with ciprofloxacin resistance in clinical bacterial isolates from intensive care unit (ICU) patients.

Prospective cohort study.

Twenty-bed medical-surgical ICU in a Canadian tertiary care teaching hospital.

All patients admitted to the ICU with a stay of at least 72 hours between January 1 and December 31, 2003.

Prospective surveillance to determine patient comorbidities, use of medical devices, nosocomial infections, use of antimicrobials, and outcomes. Characteristics of patients with a ciprofloxacin-resistant gram-negative bacterial organism were compared with characteristics of patients without these pathogens.

Ciprofloxacin-resistant organisms were recovered from 20 (6%) of 338 ICU patients, representing 38 (21%) of 178 nonduplicate isolates of gram-negative bacilli. Forty-nine percent of Pseudomonas aeruginosa isolates and 29% of Escherichia coli isolates were resistant to ciprofloxacin. In a multivariate analysis, independent risk factors associated with the recovery of a ciprofloxacin-resistant organism included duration of prior treatment with ciprofloxacin (relative risk [RR], 1.15 per day [95% confidence interval {CI}, 1.08-1.23]; P < .001), duration of prior treatment with levofloxacin (RR, 1.39 per day [95% CI, 1.01-1.91]; P = .04), and length of hospital stay prior to ICU admission (RR, 1.02 per day [95% CI, 1.01-1.03]; P = .005). Neither ICU mortality (15% of patients with a ciprofloxacin-resistant isolate vs 23% of patients with a ciprofloxacin-susceptible isolate; P = .58 ) nor in-hospital mortality (30% vs 34%; P = .81 ) were statistically significantly associated with ciprofloxacin resistance.

ICU patients are at risk of developing infections due to ciprofloxacin-resistant organisms. Variables associated with ciprofloxacin resistance include prior use of fluoroquinolones and duration of hospitalization prior to ICU admission. Recognition of these risk factors may influence antibiotic treatment decisions.

Modified contact precautions (MCP), defined as routine donning of isolation gowns (along with routine gloving) on entry into the rooms of patients under contact precautions, regardless of the likelihood of direct exposure to the patient or their immediate environment, were instituted at our medical center to reduce nosocomial transmission of common hospital pathogens.

To study compliance with MCP policy regarding routine gowning in intensive care units (ICUs) and general wards and to determine the relationship between gown and glove use in the care of patients under MCP in ICUs.

Prospective observational study from February 20, 2004, through January 8, 2005, involving 2,110 persons (1,504 healthcare workers [HCWs] and 606 non-HCW visitors).

A 900-bed tertiary care teaching community hospital.

Overall compliance with routine gown use was observed for 1,542 persons (73%), including 1,150 HCWs (76%) and 392 visitors (65%) (odds ratio [OR], 1.8 [95% confidence interval {CI}, 1.4-2.2]; P < .001). Visitors in the ICUs (186 [91%] of 204) were more likely than visitors in the general wards (202 [51%] of 398) to comply with gown use (OR, 10 [95% CI, 6.0-17.0]; P < .001). In logistic regression analysis, independent predictors of gown compliance among HCWs were female sex (OR, 2.3 [95% CI, 1.8-3.0]; P < .001) and ICU setting (OR, 2.2 [95% CI, 1.7-2.9]; P < .001). In the ICUs, gown use was highly predictive of glove use among HCWs (positive predictive value, 95%).

Improvement in compliance with gown use at our medical center will require more-intensive educational efforts targeted at male HCWs and at HCWs and visitors on general wards. In the care of ICU patients under MCP, HCW compliance with gown use may be used as a proxy for their compliance with glove use.

To identify characteristics of encounters between healthcare workers (HCWs) and patients that correlated with hand hygiene adherence among HCWs.

Observational study.

Intensive care unit in a Veterans Affairs hospital.

HCWs.

There were 767 patient encounters observed (48.6% involved nurses, 20.6% involved physicians, and 30.8% involved other HCWs); 39.8% of encounters involved patients placed under contact precautions. HCW contact with either the patient or surfaces in the patient's environment occurred during all encounters; direct patient contact occurred during 439 encounters (57.4%), and contact with environmental surfaces occurred during 710 encounters (92.6%). The median duration of encounters was 2 minutes (range, <1 to 51 minutes); 33.6% of encounters lasted 1 minute or less, with no significant occupation-associated differences in the median duration of encounters. Adherence with hand hygiene practices was correlated with the duration of the encounter, with overall adherences of 30.0% after encounters of ≤1 minute, 43.4% after encounters of >1 to ≤2 minutes, 51.1% after encounters of >3 to ≤5 minutes, and 64.9% after encounters of >5 minutes (P < .001 by the x2 for trend). In multivariate analyses, longer encounter duration, contact precautions status, patient contact, and nursing occupation were independently associated with adherence to hand hygiene recommendations.

In this study, adherence to hand hygiene practices was lowest after brief patient encounters (ie, <2 minutes). Brief encounters accounted for a substantial proportion of all observed encounters, and opportunities for hand contamination occurred during all brief encounters. Therefore, improving adherence after brief encounters may have an important overall impact on the transmission of healthcare-associated pathogens and may deserve special emphasis in the design of programs to promote adherence to hand hygiene practices.

To study the bacterial population kinetics on gloved hands following hand treatment with 3 optically indistinguishable, alcohol-based surgical hand rubs, with and without supplements to delay bacterial regrowth.

Prospective, randomized, double-blind, balanced quasi-Greco-Latin square design.

Microbiology laboratory of the Medical University Vienna, Austria.

Twenty-four healthy adult volunteers without skin lesions.

The following hand rubs, all stained blue, were applied to the hands for 3 minutes: 1-propanol 60% vol/vol (A); 2-propanol 70% m/m plus chlorhexidine gluconate 0.5% wt/wt (B); 2-propanol 45% wt/wt plus 1-propanol 30% wt/wt plus mecetronium etilsulfate 0.2% wt/wt (C). As a reference formulation (R), 1-propanol 60% vol/vol, unstained, was applied for the same amount of time.

In 8 once-weekly tests, 24 subjects randomly assigned to use the 4 hand rubs in groups of 6 persons each performed hand hygiene according to the method described in European Norm 12791. Every subject used one preparation at a time, the antimicrobial effect of which was evaluated at 2 sampling times. After week 8, each volunteer had tested every preparation at every preset sampling time. All preparations were tested in parallel.

The mean pretreatment counts of viable bacteria (in colony-forming units per milliliter) in fluid samples were not significantly different between week 1 and week 8, nor between the right and left hands (analysis of variance [ANOVA], P > .1). Immediately after applying the formulation (t0), bactericidal effects of the blinded formulations A and C were equivalent to that of the reference formulation R, whereas the effect of B was questionable. The population kinetics of the flora on the hands proceeded from large and fast initial reductions of the skin flora by 2.7 log units (A), 3.1 log units (B), 3.3 log units (reference formulation), and 3.5 log units (C), to slow regrowth. However, even after 6 hours wearing gloves viable bacterial counts remained significantly (P < .01) below the baseline values (by 0.9 log [reference formulation], 1.1 log [A and B], and 1.5 log [C]). The slowest regrowth 1 and 3 hours after application (∆ from t0, 0.1 log and 0.7 log respectively) was seen with formulation C, and the slowest regrowth after 6 hours was seen with formulation B (∆ from t0, 1.6 log). These differences did, however, not reach statistical significance.

With respect to the rapid and dramatic antibacterial action of suitable alcohols at high concentrations and with appropriate neutralizers, the contribution of supplements to the delay of bacterial regrowth on gloved hands appears rather minor, if a product only exerts an immediate effect equivalent to that of the reference disinfection procedure described in EN 12791.

Previous studies, conducted before widespread use of scrubless, alcohol-based hand sanitizers, demonstrated increased residual bacterial counts after hand hygiene on hands with jewelry.

To compare the impact of finger rings on the effectiveness of scrubless and water-aided alcohol-based hand sanitization methods with that of povidone-iodine scrub.

Randomized, controlled study.

University hospital.

Sixty volunteer subjects from a pool of perioperative staff and medical students.

After recruitment, participants wore a ring on one hand and no ring on the other hand. They were randomly assigned to perform hand hygiene with a povidone-iodine scrub, an alcohol wash, or a waterless alcohol-chlorhexidine lotion (n = 20 subjects per method). After subjects completed hand hygiene, gloves were placed on their hands by means of sterile methods, and a “glove juice” technique was used to obtain samples for culture. The number of colony-forming units in each culture was counted, and the data were compared.

There was no significant difference in the number of bacteria between hands with and hands without rings for the groups that used alcohol wash or alcohol-chlorhexidine lotion. However, for the povidone-iodine group, the number of bacteria on hands with rings was greater than the number on hands without rings (P < .05). The hands of participants who used waterless alcohol-chlorhexidine had the lowest bacterial count, regardless of the presence of rings (P < .01).

The presence of rings does not negatively impact the effectiveness of alcohol-based hand sanitizers. Use of waterless alcohol-chlorhexidine lotion resulted in the lowest bacterial count.