To determine what practices are used by hospitals to prevent ventilator-associated pneumonia (VAP) and, through qualitative methods, to understand more fully why hospitals use certain practices and not others.

Mixed-methods, sequential explanatory study.

We mailed a survey to the lead infection control professionals at 719 US hospitals (119 Department of Veterans Affairs [VA] hospitals and 600 non-VA hospitals), to determine what practices are used to prevent VAP. We then selected 14 hospitals for an in-depth qualitative investigation, to ascertain why certain infection control practices are used and others not, interviewing 86 staff members and visiting 6 hospitals.

The survey response rate was 72%; 83% of hospitals reported using semirecumbent positioning, and only 21% reported using subglottic secretion drainage. Multivariable analyses indicated collaborative initiatives were associated with the use of semirecumbent positioning but provided little guidance regarding the use of subglottic secretion drainage. Qualitative analysis, however, revealed 3 themes: (1) collaboratives strongly influence the use of semirecumbent positioning but have little effect on the use of subglottic secretion drainage; (2) nurses play a major role in the use of semirecumbent positioning, but they are only minimally involved with the use of subglottic secretion drainage; and (3) there is considerable debate about the evidence supporting subglottic secretion drainage, despite a meta-analysis of 5 randomized trials of subglottic secretion drainage that generally supported this preventive practice, compared with only 2 published randomized trials of semirecumbent positioning, one of which concluded that it was ineffective at preventing the development of VAP.

Semirecumbent positioning is commonly used to prevent VAP, whereas subglottic secretion drainage is used far less often. We need to understand better how evidence related to prevention practices is identified, interpreted, and used to ensure that research findings are reliably translated into clinical practice.

Trivalent inactivated influenza vaccine (TIV) is indicated for healthcare workers (HCWs); however, the vaccination rate in this population is estimated at 35%. We implemented a program for the administration of TIV, targeted at parents of neonatal intensive care unit (NICU) patients.

To determine the effect of availability of TIV to parents in the NICU on HCW vaccination rates.

Questionnaire survey after an intervention-based study.

Tertiary-care neonatal intensive care unit.

Physicians, nurses, and other NICU-based staff.

For the 2005-2006 influenza season, parents of NICU patients were screened and administered TIV, if informed consent was obtained. As a consequence, TIV was available 20 hours/day to all staff. Previous vaccination history and comorbidities in HCWs were also assessed.

Of 120 neonatal HCWs, 112 (93%) were screened during the 2005-2006 season; 80 (67%) were vaccinated, compared with 49 (41%) prior to the implementation of this program (P < .03, by Student's t test); 54 (45% of the study population, which includes senior neonatologists, fellow and resident physicians, nurses, respiratory therapists, X-ray technicians and clerical staff) received TIV in the NICU, compared with the 17 (14%) of 120 HCWs the previous year; and 20 (46%) of 43 HCWs of the nursing staff were vaccinated in the NICU, whereas only 3 (7%) of 43 HWCs were vaccinated outside the unit. Attending physicians had the lowest vaccination rate, and most cited efficacy and/or side effects in their deferral. Nurses most often refused influenza vaccination because they had a fear of injection.

Administration of TIV in the NICU is an effective means of increasing the vaccination rate among neonatal HCWs. To increase compliance with vaccination, educational efforts for nurses should emphasize the possibility of viral transmission to neonates as motivation for vaccination. Physician-directed efforts should include tolerability of vaccine side effects. Live attenuated influenza vaccine, administered intranasally, should be considered to increase vaccination rates among NICU nurses.

The impact of methicillin-resistant Staphylococcus aureus (MRSA) colonization on mortality has not been well characterized. We sought to describe the impact of MRSA colonization on patients admitted to intensive care units (ICUs) in the Birmingham Veterans Affairs Medical Center (VAMC).

We conducted a retrospective cohort study of ICU patients at the Birmingham VAMC during 2005 to evaluate the predictors of MRSA colonization and determine its effect on clinical outcomes. Surveillance cultures for MRSA were performed on admission to the ICU and weekly thereafter. Clinical findings, the incidence of MRSA infection, and mortality within 3 months after ICU admission were recorded. Predictors of mortality and S. aureus colonization were determined using multivariable models.

S. aureus colonization was present in 97 (23.3%) of 416 patients screened, of whom 67 (16.1%) were colonized with methicillin-susceptible S. aureus (MSSA) and 30 (7.2%) with MRSA. All-cause mortality at 3 months among MRSA-colonized patients was significantly greater than that among MSSA-colonized patients (46.7% vs 19.4%; P = .009). MRSA colonization was an independent predictor of death (adjusted odds ratio [OR] ,3.7 [95% confidence interval {CI}, 1.5–8.9]; P = .003) and onset of MRSA infection after hospital discharge (adjusted OR, 7.6 [95% CI, 2.48–23.2]; P < .001). Risk factors for MRSA colonization included recent antibiotic use (adjusted OR, 4.8 [95% CI, 1.9–12.2]; P = .001) and dialysis (adjusted OR, 18.9 [95% CI, 2.1–167.8]; P = .008).

Among ICU patients, MRSA colonization is associated with subsequent MRSA infection and an all-cause mortality that is greater than that for MSSA colonization. Active surveillance for MRSA colonization may identify individuals at risk for these adverse outcomes. Prospective studies of outcomes in MRSA-colonized patients may better define the role of programs for active MRSA surveillance.

To investigate the mode of transmission of imipenem-resistant Acinetobacter baumannii strains causing episodes of sepsis.

A 7-bed trauma intensive care unit (ICU) in an orthopedic hospital in Greece.

During a 14-week period (from January 10 to April 16, 2006), clinical specimens, along with samples taken on a weekly basis from the ICU environment and from the hands of health care workers (HCWs), were prospectively tested for imipenem-resistant A. baumannii. Pulsed-field gel electrophoresis was used to study the genetic relatedness of the isolates recovered from these specimens and samples.

During the survey, imipenem-resistant A. baumannii was identified in 14 hospitalized patients, from whom 40 multidrug-resistant and imipenem-resistant A. baumanii isolates were recovered. These pathogens caused episodes of bacteremia and sepsis in all but one of the patients and contributed to the death of 3 patients. Samples for culture were obtained from the environment and from the hands of HCWs; 29 imipenem-resistant A. baumannii isolates were recovered from the environment, and 12 from HCWs. One predominant genotype and 2 less predominant genotypes were detected among the 81 imipenem-resistant A. baumannii isolates. All 3 of these genotypes were found among patients and HCWs and were recovered from environmental samples.

Control measures consisted of the closure of the ICU and the transfer of the patients to other units. The ICU was disinfected, and adherence to proper hand hygiene protocol was reinforced. These same clonal isolates were not recovered from clinical or environmental samples during the month after the reopening of the ICU.

The extensive dissemination of imipenem-resistant A. baumannii clonal strains causing episodes of bacteremia and/or sepsis resulted from modes of transmission via multiple contaminated surfaces and objects and transiently colonized HCWs' hands. Closure of the ICU and its meticulous environmental decontamination led to the successful control of the outbreak.

To investigate whether there is a correlation between the rates of antimicrobial drug consumption in hospital departments and the prevalence of antimicrobial resistance among clinically important bacteria recovered in the hospital.

Retrospective study.

Tertiary care hospital in Greece.

Data on antimicrobial consumption (from January 2001 through December 2004) were expressed as defined daily doses per 100 bed-days. The prevalence of antimicrobial resistance among isolates of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterococcusfaecium recovered during the same time period were calculated by the microbiology department. We then performed the following analyses: (1) a comparison of the consumption rates for different antimicrobial groups in individual hospital departments, (2) a comparison of the prevalence of resistance to different antimicrobials, and (3) a correlation analysis of antimicrobial consumption rates and the prevalence of antimicrobial resistance.

The rates of antimicrobial consumption and the prevalence of resistance varied substantially among the hospital's departments. The annual rate of consumption for carbapenems correlated with the rate of consumption for glycopeptides and third-generation cephalosporins (P < .05). Among P. aeruginosa isolates, the prevalence of imipenem resistance correlated with the prevalence of resistance to amikacin, ciprofloxacin, and ceftazidime (P < .05). The rate of carbapenem consumption correlated with the prevalence of imipenem resistance among P. aeruginosa and A. baumannii isolates (P < .05). The rate of aminoglycoside consumption correlated with the prevalence of amikacin resistance among P. aeruginosa, K. pneumoniae, and E. coli isolates (P < .05). However, the rate of consumption for fluoroquinolones and glycopeptides had no correlation with the prevalence of ciprofloxacin resistance among gram-negative bacteria or vancomycin resistance among E. faecium isolates.

These data are suggestive of a differential relationship between antimicrobial consumption and the prevalence of antimicrobial resistance among various species and for various antimicrobial agents. These findings may help to optimize antimicrobial prescription policies in the hospital, especially in departments that have both high rates of antimicrobial consumption and a high prevalence of antimicrobial resistance.

We evaluated the effect of an antimicrobial management effort to decrease ciprofloxacin use on the antibiotic susceptibility of nosocomial Pseudomonas aeruginosa isolates.

Retrospective, observational study.

Tertiary care teaching hospital with 731 beds.

The study was conducted between January 1, 2001, and December 31, 2007. Linear regression analyses and Student t tests were used to determine significant changes in drug use among patients and antimicrobial susceptibility patterns among nosocomial P. aeruginosa isolates during the 84-month period.

Following implementation of a program to reduce oral and intravenous use of ciprofloxacin in 2005, there was a 56.6% reduction in ciprofloxacin use (P < .001). Significant reductions in the mean percentage of nosocomial P. aeruginosa isolates that were resistant to ciprofloxacin (from 45.0% to 35.2%; P < .002) and the mean incidence of ciprofloxacin resistance (from 0.77 to 0.67 isolates recovered per 1,000 patient-days; P = .03) were noted after implementation of this program. The total quantity of antipseudomonal antibiotics consumed decreased, but the use of certain antipseudomonal antibiotics (ie, cefepime and imipenem/meropenem) increased. Among nosocomial P. aeruginosa isolates, the prevalence of imipenem/meropenem resistance increased, whereas the prevalence of cefepime resistance did not. During the 84 months of the study, there was a significant association between ciprofloxacin use and the percentage of nosocomial P. aeruginosa isolates that were resistant to ciprofloxacin (p = 0.47; P = .011), but there was no correlation between ciprofloxacin use and the incidence of ciprofloxacin resistance (p = 0.21; P = .26).

Major reductions in ciprofloxacin use were associated with small but significant improvements in the rate of ciprofloxacin susceptibility among nosocomial P. aeruginosa isolates. The impact of the program on other antipseudomonal agents was variable.

To describe the epidemiology of hospital-acquired infections (HAIs) in veterans with spinal cord injury and disorder (SCI&D).

Retrospective medical record review.

Midwestern Department of Veterans Affairs spinal cord injury center.

A total of 226 patients with SCI&D hospitalized at least once during a 2-year period (October 1, 2001, through September 30, 2003).

A total of 549 hospitalizations were included in the analysis (mean duration of hospitalization, 33.7 days); an HAI occurred during 182 (33.2%) of these hospitalizations. A total of 657 HAIs occurred during 18,517 patient-days in the hospital (incidence rate, 35.5 HAIs per 1,000 patient-days). Almost half of the 226 patients had at least 1 HAI; the mean number of HAIs among these patients was 6.0 HAIs per patient. The most common HAIs were urinary tract infection (164 [25.0%] of the 657 HAIs; incidence rate, 8.9 cases per 1,000 patient-days), bloodstream infection (111 [16.9%]; incidence rate, 6.0 cases per 1,000 patient-days), and bone and joint infection (103 [15.7%]; incidence rate, 5.6 cases per 1,000 patient-days). The most common culture isolates were gram-positive bacteria (1,082 [45.6%] of 2,307 isolates), including Staphylococcus aureus, and gram-negative bacteria (1,033 [43.6%] of isolates), including Pseudomonas aeruginosa. Multivariate regression demonstrated that predictors of HAI were longer length of hospital stay (P = .002), community-acquired infection (P = .007), and use of a urinary invasive device (P = .01) or respiratory invasive device (P = .04).

The overall incidence of HAIs in persons with SCI&D was higher than that reported for other populations, confirming the increased risk of HAI in persons with spinal cord injury. The increased risk associated with longer length of stay and with community-acquired infection suggests that strategies are needed to reduce the duration of hospitalization and to effectively treat community-acquired infection, to decrease infection rates. There is significant room for improvement in reducing the incidence of HAIs in this population.

To determine the effectiveness of oral decontamination with 2% chlorhexidine solution for the prevention of ventilator-associated pneumonia (VAP).

Randomized controlled trial and meta-analysis.

A tertiary care university hospital in Bangkok, Thailand.

Adult patients who received mechanical ventilation and who were hospitalized in intensive care units and general medical wards.

The patients were randomized to receive oral decontamination with 2% chlorhexidine solution or normal saline solution 4 times per day until their endotracheal tubes were removed. The outcome measures were the development of VAP and oropharyngeal colonization with gram-negative bacilli. Meta-analysis was performed by combining the results of the present study with those from another randomized controlled trial that also used a 2% chlorhexidine formulation for oral decontamination.

The characteristics of the patients in the chlorhexidine group (n = 102) and the normal saline group (n = 105) were not significantly different. The incidence of VAP in the chlorhexidine group was 4.9% (5 of 102), and the incidence in the normal saline group was 11.4% (12 of 105) (P = .08). The rate of VAP in the chlorhexidine group was 7 episodes per 1,000 ventilator-days, and the rate in the normal saline group was 21 episodes per 1,000 ventilator-days (P = .04). Irritation of the oral mucosa was observed in 10 (9.8%) of the patients in the chlorhexidine group and in 1 (0.9%) of the patients in the normal saline group (P = .001). Oropharyngeal colonization with gram-negative bacilli was either reduced or delayed in the chlorhexidine group. Overall mortality of the patients did not differ significantly between the groups. Meta-analysis of 2 randomized controlled trials revealed an overall relative risk of VAP for patients in the chlorhexidine group of 0.53 (95% confidence interval, 0.31-0.90; P = .02).

Oral decontamination with 2% chlorhexidine solution is an effective and safe method for preventing VAP in patients who receive mechanical ventilation.

To validate the National Nosocomial Infection Surveillance (NNIS) risk index as a tool to account for differences in case mix when reporting rates of complex surgical site infection (SSI).

Prospective cohort study.

Twenty-four community hospitals in the southeastern United States.

We identified surgical procedures performed between January 1, 2005, and June 30, 2007. The Goodman-Kruskal gamma or G statistic was used to determine the correlation between the NNIS risk index score and the rates of complex SSI (not including superficial incisional SSI). Procedure-specific analyses were performed for SSI after abdominal hysterectomy, cardiothoracic procedures, colon procedures, insertion of a hip prosthesis, insertion of a knee prosthesis, and vascular procedures.

A total of 2,257 SSIs were identified during the study period (overall rate, 1.19 SSIs per 100 procedures), of which 1,093 (48.4%) were complex (0.58 complex SSIs per 100 procedures). There were 45 complex SSIs identified following 7,032 abdominal hysterectomies (rate, 0.64 SSIs per 100 procedures); 63 following 5,318 cardiothoracic procedures (1.18 SSIs per 100 procedures); 139 following 5,144 colon procedures (2.70 SSIs per 100 procedures); 63 following 6,639 hip prosthesis insertions (0.94 SSIs per 100 procedures); 73 following 9,658 knee prosthesis insertions (0.76 SSIs per 100 procedures); and 55 following 6,575 vascular procedures (0.84 SSIs per 100 procedures). All 6 procedure-specific rates of complex SSI were significantly correlated with increasing NNIS risk index score (P< .05).

Some experts recommend reporting rates of complex SSI to overcome the widely acknowledged detection bias associated with superficial incisional infection. Furthermore, it is necessary to compensate for case-mix differences in patient populations, to ensure that intrahospital comparisons are meaningful. Our results indicate that the NNIS risk index is a reasonable method for the risk stratification of complex SSIs for several commonly performed procedures.

To evaluate the efficacy of a standardized regimen for decolonization of methicillin-resistant Staphylococcus aureus (MRSA) carriers and to identify factors influencing decolonization treatment failure.

Prospective cohort study from January 2002 to April 2007, with a mean follow-up period of 36 months.

University hospital with 750 beds and 27,000 admissions/year.

Of 94 consecutive hospitalized patients with MRSA colonization or infection, 32 were excluded because of spontaneous loss of MRSA, contraindications, death, or refusal to participate. In 62 patients, decolonization treatment was completed. At least 6 body sites were screened for MRSA (including by use of rectal swabs) before the start of treatment.

Standardized decolonization treatment consisted of mupirocin nasal ointment, chlorhexidine mouth rinse, and full-body wash with chlorhexidine soap for 5 days. Intestinal and urinary-tract colonization were treated with oral vancomycin and cotrimoxazole, respectively. Vaginal colonization was treated with povidone-iodine or, alternatively, with chlorhexidine ovula or octenidine solution. Other antibiotics were added to the regimen if treatment failed. Successful decolonization was considered to have been achieved if results were negative for 3 consecutive sets of cultures of more than 6 screening sites.

The mean age (± standard deviation [SD]) age of the 62 patients was 66.2 ± 19 years. The most frequent locations of MRSA colonization were the nose (42 patients [68%]), the throat (33 [53%]), perianal area (33 [53%]), rectum (36 [58%]), and inguinal area (30 [49%]). Decolonization was completed in 87% of patients after a mean (±SD) of 2.1 ± 1.8 decolonization cycles (range, 1-10 cycles). Sixty-five percent of patients ultimately required peroral antibiotic treatment (vancomycin, 52%; cotrimoxazole, 27%; rifampin and fusidic acid, 18%). Decolonization was successful in 54 (87%) of the patients in the intent-to-treat analysis and in 51 (98%) of 52 patients in the on-treatment analysis.

This standardized regimen for MRSA decolonization was highly effective in patients who completed the full decolonization treatment course.

The prevalence of serious infections caused by multidrug-resistant pathogens transmitted in the hospital setting has reached alarming levels, despite intensified interventions. In the context of mandates that hospitals ensure compliance with disinfection procedures of surfaces in the environment surrounding the patient, we implemented a multihospital project to both evaluate and improve current cleaning practices.

Prospective quasi-experimental, before-after, study.

Thirty-six acute care hospitals in the United States ranging in size from 25 to 721 beds.

We used a fluorescent targeting method to objectively evaluate the thoroughness of terminal room disinfection cleaning before and after structured educational and procedural interventions.

Of 20,646 standardized environmental surfaces (14 types of objects), only 9,910 (48%) were cleaned at baseline (95% confidence interval, 43.4-51.8). Thoroughness of cleaning at baseline correlated only with hospital expenditures for environmental services personnel (P = .02). After implementation of interventions and provision of objective performance feedback to the environmental services staff, it was determined that 7,287 (77%) of 9,464 standardized environmental surfaces were cleaned (P < .001). Improvement was unrelated to any demographic, fiscal, or staffing parameter but was related to the degree to which cleaning was suboptimal at baseline (P < .001).

Significant improvements in disinfection cleaning can be achieved in most hospitals, without a substantial added fiscal commitment, by the use of a structured approach that incorporates a simple, highly objective surface targeting method, repeated performance feedback to environmental services personnel, and administrative interventions. However, administrative leadership and institutional flexibility are necessary to achieve success, and sustainability requires an ongoing programmatic commitment from each institution.

To study the impact of a multimodal infection control program on the rate of nosocomial infections at a 550-bed tertiary care center.

Before and after the implementation of an infection control program, the rate of nosocomial infection was recorded in time-interval prevalence studies. Hand hygiene compliance was studied before and after the intervention. As a surrogate marker of compliance, the amount of alcohol-based hand rub consumed before the intervention was compared with the amount consumed after the intervention. The intervention included additional staff for infection control, repeated instructions for hand hygiene, new guidelines for preoperative antibiotic prophylaxis, and isolation of patients infected or colonized with multidrug-resistant bacteria.

The rate of nosocomial infection decreased from approximately 11.7% to 6.8% in 2 years. The rate of hand hygiene compliance increased by 20.0%; it was 59.0% before the intervention and increased to 79.0% afterward. These results correlate with data on the consumption of alcohol-based hand rub, but not with data on the use of antibiotics.

Within 2 years, a multimodal infection control program intervention such as this one may reduce the rate of nosocomial infection at a tertiary care center by more than one-third and improve both the quality of care and patient outcomes. It may also generate considerable savings. Therefore, such programs should be promoted not only by hospital epidemiologists but also by hospital administrators.

To evaluate the time trend in the surgical site infection (SSI) rate in relation to the duration of surveillance in The Netherlands.

Forty-two hospitals that participated in the the Dutch national nosocomial surveillance network, which is known as PREZIES (Preventie van Ziekenhuisinfecties door Surveillance), and that registered at least 1 of the following 5 frequently performed surgical procedures for at least 3 years during the period from 1996 through 2006: mastectomy, colectomy, replacement of the head of the femur, total hip arthroplasty, or knee arthroplasty.

Analyses were performed for each surgical procedure. The surveillance time to operation was stratified in consecutive 1-year periods, with the first year as reference. Multivariate logistic regression analysis was performed using a random coefficient model to adjust for random variation among hospitals. All models were adjusted for method of postdischarge surveillance.

The number of procedures varied from 3,031 for colectomy to 31,407 for total hip arthroplasty, and the SSI rate varied from 1.6% for knee arthroplasty to 12.2% for colectomy. For total hip arthroplasty, the SSI rate decreased significantly by 6% per year of surveillance (odds ratio [OR], 0.94 [95% confidence interval {CI}, 0.90–0.98]), indicating a 60% decrease after 10 years. Nonsignificant but substantial decreasing trends in the rate of SSI were found for replacement of the head of the femur (OR, 0.94 [95% CI, 0.88–1.00]) and for colectomy (OR, 0.92 [95% CI, 0.83–1.02]).

Even though most decreasing trends in the SSI rate were not statistically significant, they were encouraging. To use limited resources as efficiently as possible, we would suggest switching the surveillance to another surgical procedure when the SSI rate for that particular procedure has decreased below the target rate.

During influenza outbreaks, fever and cough are the most accurate symptoms in predicting influenza virus infection in the community.

To determine the usefulness of fever, cough, and other symptoms for diagnosing influenza virus infection in hospitalized patients.

Prospective cohort study.

Three wards (pulmonology, internal medicine and infectious diseases, and geriatrics) of a tertiary care hospital in the Netherlands.

All patients staying in the wards during peak national influenza activity in the 2005-2006 and 2006-2007 influenza seasons.

During peak influenza activity, the presence of fever, cough, and/or other symptoms possibly associated with influenza was monitored for all patients, and nose and throat swab samples were taken twice weekly for virologic analysis.

Of 264 patients, 23 (9%) tested positive for influenza virus. The positive predictive value of fever and cough for the diagnosis of influenza virus infection was 23% (95% confidence interval, 0%-62%), and the sensitivity was 35% (95% confidence interval, 11%-58%). The combination of symptoms with the highest positive predictive value (40%) was that of cough, chills, and obstructed nose or coryza. The combination of cough and chills or fever had the highest sensitivity (60%). None of the combinations of symptoms had both a positive predictive value and a sensitivity higher than 40%.

Both the sensitivity and the positive predictive value of fever, cough, and/or other symptoms for the diagnosis of influenza virus infection in hospitalized patients are low. The use of these common symptoms for treatment decisions and infection control management will probably be insufficient to contain a nosocomial outbreak, because many influenza cases will remain unidentified.

Serratia marcescens causes healthcare-associated infections and significant morbidity and mortality in neonatal intensive care units (NICUs). We report the investigation and control of an outbreak of multidrug-resistant (MDR) S. marcescens infection at an NICU.

An outbreak investigation and a case-control study were undertaken at a 36-bed NICU in a tertiary care hospital in Baltimore, Maryland, for the period from October 2004 through February 2005. The outbreak investigation included case identification, review of medical records, environmental cultures, patient surveillance cultures, personnel hand cultures, and pulsed-field gel electrophoresis (PFGE). The case-control study included case identification and review of medical records. Infection control measures were implemented. Eighteen NICU neonates had cultures that grew MDR S. marcescens during the study period. The case-control study included 16 patients with the outbreak strain or an unidentified strain of MDR S. marcescens and 32 control patients not infected and/or colonized with MDR S. marcescens, treated in the NICU for at least 48 hours during the study period.

PFGE analysis identified a single strain of MDR S. marcescens that infected or colonized 15 patients. Two patients had unique strains, and 1 patient's isolate could not be subtyped. An unrelated MDR S. marcescens isolate was recovered from a sink drain. Exposure to inhalational therapy was an independent risk factor for MDR S. marcescens acquisition after adjusting for birth weight. Extensive investigation failed to reveal a point source for the outbreak.

A single epidemic strain of MDR S. marcescens spread rapidly and threatened to become endemic in this NICU. Transient carriage on the hands of healthcare personnel or on respiratory care equipment was the likely mode of transmission. Cohorting patients and staff, at the cost of bed closures and additional personnel, interrupted transmission and halted the outbreak.

To identify risk factors for surgical site infection (SSI) due to methicillin-resistant Staphylococcus aureus (MRSA).

Prospective case-control study.

One tertiary and 6 community-based institutions in the southeastern United States.

We compared patients with SSI due to MRSA with 2 control groups: matched uninfected surgical patients and patients with SSI due to methicillin-susceptible S. aureus (MSSA). Multivariable logistic regression was used to determine variables independently associated with SSI due to MRSA, compared with each control group.

During the 5-year study period, 150 case patients with SSI due to MRSA were identified and compared with 231 matched uninfected control patients and 128 control patients with SSI due to MSSA. Two variables were independendy associated with SSI due to MRSA in both multivariable regression models: need for assistance with 3 or more activities of daily living (odds ratio [OR] compared with uninfected patients, 3.97 [95% confidence interval {CI}, 2.18-7.25]; OR compared with patients with SSI due to MSSA, 3.88 [95% CI, 1.91-7.87]) and prolonged duration of surgery (OR compared with uninfected patients, 1.98 [95% CI, 1.11-3.55]; OR compared with patients with SSI due to MSSA, 2.33 [95% CI, 1.17-4.62]). Lack of independence (ie, poor functional status) remained associated with an increased risk of SSI due to MRSA after stratifying by age.

Poor functional status was highly associated with SSI due to MRSA in adult surgical patients, regardless of age. A patient's level of independence can be easily determined, and this information can be used preoperatively to target preventive interventions.

Upper-room air UV germicidal irradiation (UVGI) is an effective environmental control measure for mitigating the transmission of airborne infections. Many factors influence the efficacy of an upper-room air UVGI system, including the levels and distribution of radiation. The radiation levels experienced by airborne microorganisms can be estimated by measuring the fluence rate, which is the irradiance from all angles that is incident on a small region of space.

The fluence rate can be estimated by use of a radiometer coupled to a planar detector. Measurements in 4 directions at a single point are taken and summed to estimate the fluence rate at that point. This measurement process is repeated at different sites in the room at a single height.

In the upper air of a test room, the UV fluence rate varied at least 3-fold, with the maximum rate occurring in the immediate vicinity of the fixtures containing lamps emitting UV radiation. In the area that would be occupied by the patient and/or healthcare personnel, no significant variation occurred in the UV fluence rate for a designated height. There was no significant statistical difference between measurements obtained by different individuals, by using a different alignment, or during 5 observation periods. Lamp failures were detected on multiple occasions.

This method is simple, requires no specialized training, and permits regular monitoring of the necessary UV fluence rates needed to sustain the targeted airborne microorganisms' inactivation level. Additionally, this method allowed for the detection of changes in UV fluence rates in the upper air of the simulated hospital room.

To describe the results of a simulation study of the spread of pandemic influenza, the effects of public health measures on the simulated pandemic, and the resultant adequacy of the surge capacity of the hospital infrastructure and to investigate the adequacy of key elements of the national pandemic influenza plan to reduce the overall attack rate so that surge capacity would not be overwhelmed.

We used 2 discrete-event simulation models: the first model simulates the contact and disease transmission process, as affected by public health interventions, to produce a stream of arriving patients, and the second model simulates the diagnosis and treatment process and determines patient outcomes.

Hypothetical scenarios were based on the response plans, infrastructure, and demographic data of the population of San Antonio, Texas.

Use of a mix of strategies, including social distancing, antiviral medications, and targeted vaccination, may limit the overall attack rate so that demand for care would not exceed the capacity of the infrastructure. Additional simulations to assess social distancing as a sole mitigation strategy suggest that a reduction of infectious community contacts to half of normal levels would have to occur within approximately 7 days.

Under ideal conditions, the mix of strategies may limit demand, which can then be met by community surge capacity. Given inadequate supplies of vaccines and antiviral medications, aggressive social distancing alone might allow for the control of a local epidemic without reliance on outside support.