National Nosocomial Infections Surveillance System Research Articles

Regarding the risk for development of surgical site infections and bacterial prophylaxis in liver transplantation

Regarding the risk for development of surgical site infections and bacterial prophylaxis in liver transplantation

Nosocomial Infections in a Medical-Surgical Intensive Care Unit

Objective: We aimed to describe the pattern of nosocomial infections in an adult medical-surgical intensive care unit (ICU). Subjects and Methods: A 2-year prospective cohort study of nosocomial infection surveillance in a 15-bed adult combined medical and surgical ICU of Farwaniya Hospital, Kuwait, was carried out. Data were collected between January 2004 and December 2005 using the standard surveillance protocols and nosocomial infection site definitions of the National Nosocomial Infections Surveillance System’s ICU surveillance component. Results: Of 1,173 patients hospitalized in the ICU for an aggregate duration of 6,855 days, 89 patients acquired a total of 140 nosocomial infections; 46 (33%) ventilator-associated pneumonia (VAP), 33 (24%) central-line-associated bloodstream infection and 15 (11%) catheter-associated urinary tract infection, 22 (16%) cutaneous infection and 24 (17%) other infections. The overall patient day rate was 20.6/1,000 patient days. The patient infection rate was 10.6/100 patients at risk. The mean VAP rate was 9.1/1,000 ventilator days (95% CI, 5–13.2), the central-line-associated bloodstream infection rate 5.5/1,000 central line days (95% CI, 3.2–7.8) and the catheter-associated urinary tract infection rate 2.3/1,000 catheter days (95% CI, 1.2–3.4). Of all nosocomial infections, 119 (85%) were culture-confirmed and 21 (15%) were clinically defined culture-negative infections. Of the culture-confirmed nosocomial infections, 81 (68%) were Gram-negative, 32 (27%) Gram-positive and 6 (5%) fungal. The most frequent organism was Pseudomonas aeruginosa (20, 17%), followed by Acinetobacter baumannii (15, 13%), Klebsiella spp. (13, 11%) and Escherichia coli (10, 8%). The crude mortality was 27% among ICU-infected patients. Conclusion: VAP was the most common nosocomial infection in our ICU. Gram-negative organisms were more commonly reported as etiologic agents of ICU infections.

Comparative Analysis of 75th Percentile Durations for Neurosurgical Procedures in France and in US National Noscomial Infection Surveillance System Data

The duration of surgical procedures and the 75th percentiles of those durations are considered in calculation of the US National Nosocomial Infection Surveillance (NNIS) system risk index score. To compare the durations of neurosurgical procedures in a hospital in western France with the durations in the NNIS data, 6,136 neurosurgical patients were followed up to determine surgical site infection rates. The surgical site infection rate was 1.9%, and the 75th percentile durations were lower than those in the NNIS data. The values from the NNIS data are thus inadequate for this neurosurgical center.

Dissemination of the CDC's Hand Hygiene Guideline and impact on infection rates

The diffusion of national evidence-based practice guidelines and their impact on patient outcomes often go unmeasured. Our objectives were to (1) evaluate implementation and compliance with clinical practices recommended in the new Centers for Disease Control and Prevention (CDC) Hand Hygiene Guideline, (2) compare rates of health care-associated infections (HAI) before and after implementation of the Guideline recommendations, and (3) examine the patterns and correlates of changes in rates of HAI. We used pre- and post-Guideline implementation site visits and surveys in the setting of 40 US hospitals--members of the National Nosocomial Infections Surveillance System--and measured HAI rates 1 year before and after publication of the CDC Guideline and used direct observation of hand hygiene compliance and Guideline implementation scores. All study hospitals had changed their policies and procedures and provided products in compliance with Guideline recommendations; 89.8% of 1359 staff members surveyed anonymously reported that they were familiar with the Guideline. However, in 44.2% of the hospitals (19/40), there was no evidence of a multidisciplinary program to improve compliance. Hand hygiene rates remained low (mean, 56.6%). Rates of central line-associated bloodstream infections were significantly lower in hospitals with higher rates of hand hygiene (P < .001). No impact of Guideline implementation or hand hygiene compliance on other HAI rates was identified. Other factors occurring over time could affect rates of HAI. Observed hand hygiene compliance rates were likely to overestimate rates in actual practice. The study may have been of too short duration to detect the impact of a practice guideline. Wide dissemination of this Guideline was not sufficient to change practice. Only some hospitals had initiated multidisciplinary programs; practice change is unlikely without such multidisciplinary efforts and explicit administrative support.

Surgical Site Infection After Surgery to Repair Femoral Neck Fracture: A French Multicenter Retrospective Study

Femoral neck fracture is the most frequent orthopedic emergency among elderly persons. Despite a high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage in this population, no multicenter study of antibiotic prophylaxis practices and the rate and microbiological characteristics of surgical site infection (SSI) has been performed in France. Retrospective, multicenter cohort study. Twenty-two university and community hospitals in France. Each center provided data on 25 consecutive patients who underwent surgery for femoral neck fracture during the first quarter of 2005. Demographic, clinical, and follow-up characteristics were recorded, and most patients had a follow-up office visit or were involved in a telephone survey 1 year after surgery. These 22 centers provided data on 541 patients, 396 (73%) of whom were followed up 1 year after surgery. Of 504 (93%) patients for whom antibiotic prophylaxis was recorded, 433 (86%) received a cephalosporin. Twenty-two patients had an SSI, for a rate of 5.6% (95% confidence interval, 3.7-8.0). SSI was reported for 15 (6.9%) of patients who had a prosthesis placed and for 7 (3.9%) who underwent osteosynthesis (P=.27). SSI was diagnosed a median of 30 days after surgery (interquartile range, 21-41 days); 7 (32%) of these SSIs were superficial infections, and 15 (68%) were deep or organ-space infections. MRSA caused 7 SSIs (32%), Pseudomonas aeruginosa caused 5 (23%), other staphylococci caused 4 (18%), and other bacteria caused 2 (9%); the etiologic pathogen was unknown in 4 cases (18%). Reoperation was performed for 14 patients with deep or organ-space SSI, including 6 of 7 patients with MRSA SSI. The mortality rate 1 year after surgery was 20% overall but 50% among patients with SSI. In univariate analysis, only the National Nosocomial Infections Surveillance System risk index score was significantly associated with SSI (P=.006). SSI after surgery for femoral neck fracture is severe, and MRSA is the most frequently encountered etiologic pathogen. A large, multicenter prospective trial is necessary to determine whether the use of antibiotic prophylaxis effective against MRSA would decrease the SSI rate in this population.

An Alternative Scoring System to Predict Risk for Surgical Site Infection Complicating Coronary Artery Bypass Graft Surgery

To analyze the risk factors for surgical site infection (SSI) complicating coronary artery bypass graft (CABG) surgery and to create an alternative SSI risk score based on the results of multivariate analysis. A prospective cohort study involving inpatient and laboratory-based surveillance of patients who underwent CABG surgery over a 27-month period from January 1, 2003 through March 31, 2005. Data were obtained from 6 acute care hospitals in Victoria, Australia, that contributed surveillance data for SSI complicating CABG surgery to the Victorian Hospital Acquired Infection Surveillance System Coordinating Centre and the Australasian Society of Cardiac and Thoracic Surgeons, also in Victoria. A total of 4,633 (93%) of the 4,987 patients who underwent CABG surgery during this period were matched in the 2 systems databases. There were 286 SSIs and 62 deep or organ space sternal SSIs (deep or organ space sternal SSI rate, 1.33%). Univariate analysis revealed that diabetes mellitus, body mass index (BMI) greater than 35, and receipt of blood transfusion were risk factors for all types of SSI complicating CABG surgery. Six multivariate analysis models were created to examine either preoperative factors alone or preoperative factors combined with operative factors. All models revealed diabetes and BMI of 30 or greater as risk factors for SSI complicating CABG surgery. A new preoperative scoring system was devised to predict sternal SSI, which assigned 1 point for diabetes, 1 point for BMI of 30 or greater but less than 35, and 2 points for BMI of 35 or greater. Each point in the scoring system represented approximately a doubling of risk of SSI. The new scoring system performed better than the National Nosocomial Infections Surveillance System (NNIS) risk index at predicting SSI. A new weighted scoring system based on preoperative risk factors was created to predict sternal SSI risk following CABG surgery. The new scoring system outperformed the NNIS risk index. Future studies are needed to validate this scoring system.

Measurement of the Impact of Risk Adjustment for Central Line–Days on Interpretation of Central Line–Associated Bloodstream Infection Rates

To describe methods to assess the practical impact of risk adjustment for central line-days on the interpretation of central line-associated bloodstream infection (BSI) rates, because collecting these data is often burdensome. We analyzed data from 247 hospitals that reported to the adult and pediatric intensive care unit component of the National Nosocomial Infections Surveillance System from 1995 through 2003. For each unit each year, we calculated the percentile error as the absolute value of the difference between the percentile based on a risk-adjusted or more-sophisticated measure (eg, the central line-day rate) and the percentile based on a crude or less-sophisticated measure (eg, the patient-day rate). Using rate per central line-day as the "gold standard," we calculated performance characteristics (eg, sensitivity and predictive values) of rate per patient-day for finding central line-associated BSI rates higher or lower than the mean. Greater impact of risk adjustment is indicated by higher values for percentile error and lower values for performance characteristics. The median percentile error was +/-7 (i.e., the percentile based on central line-days could be 7% higher or lower than the percentile based on patient-days). This error was less than 10 percentile points for 62% of the unit-years, was between 10 and 19 percentile points for 22% of the unit-years, and was 20 percentile points or more for 15% of the unit-years. Use of the rate based on patient-days had a sensitivity of 76% and a positive predictive value of 61% for detecting a significantly high or low central line-associated BSI rate. We found that risk adjustment for central line-days has an important impact on the calculated central line-associated BSI percentile for some units. Similar methods can be used to evaluate the impact of other risk adjustment methods. Our results support current recommendations to use central line-days for surveillance of central line-associated BSI when comparisons are made among facilities.

Comparison of the Risk of Surgical Site Infection After Laparoscopic Cholecystectomy and Open Cholecystectomy

We assessed the independent contributions of the surgical approach and other variables of the National Nosocomial Infections Surveillance System (NNIS) surgical patient component to the surgical site infection risk after cholecystectomy. Laparoscopic cholecystectomy was associated with a lower overall risk of surgical site infection and a lower risk of incisional infection but not a reduced risk of organ-space infection, compared with open cholecystectomy. The contribution of most of the variables of the NNIS surgical patient component to the risk of surgical site infection depended on the depth of the infection.

Risk Factors for Surgical Site Infection Complicating Laminectomy

To examine risk factors for surgical site infection (SSI) following spinal surgery and to analyze the associations between a surgeon's years of operating experience and surgical specialty and patients' SSI risk. Case-control study. A tertiary care facility and a community hospital in Durham, North Carolina. Each case patient who developed an SSI complicating laminectomy was matched with 2 noninfected control patients by hospital, year of surgery, and National Nosocomial Infection Surveillance System risk index score. Forty-one case patients with SSI complicating laminectomy and 82 matched control patients were analyzed. Nonwhite race, diabetes and an elevated body mass index (BMI) were more common among case patients than among control patients. Subjects with a BMI greater than 35 were more likely to undergo a prolonged procedure, compared with case patients who had a BMI of 35 or less. The SSI rate for patients operated on by neurosurgeons was 28%, compared with 43% for patients operated on by orthopedic surgeons (odds ratio [OR], 0.5; P=.12). The number of years of operating experience were not associated with SSI risk. Multivariate analysis revealed diabetes (OR, 4.2 [95% confidence interval {CI}, 1.1-16.3]; P=.04), BMI greater than 35 (OR, 7.1 [95% CI, 1.8-28.3]; P=.005), and laminectomy at a level other than cervical (OR, 6.7 [95% CI, 1.4-33.3]; P=.02) as independent risk factors for SSI following laminectomy. Diabetes, obesity, and laminectomy at a level other than cervical are independent risk factors for SSI following laminectomy. Preoperative weight loss and tight perioperative control of blood glucose levels may reduce the risk of SSI in laminectomy patients.

Attitudes toward practice guidelines among intensive care unit personnel: A cross-sectional anonymous survey

The study assessed attitudes of intensive care unit (ICU) staff members toward practice guidelines in general and toward a specific guideline, The Centers for Disease Control and Prevention's Guideline for Hand Hygiene in Healthcare Settings; correlated these attitudes with staff and hospital characteristics; and examined the impact of staff attitudes toward the Hand Hygiene Guideline on self-reported implementation of the Guideline. We performed a cross-sectional survey of staff in 70 ICUs in 39 U.S. hospitals, members of The National Nosocomial Infection Surveillance System. A survey, "Attitudes Regarding Practice Guidelines," was administered anonymously to all willing staff during a site visit at each hospital. A total of 1359 ICU personnel responded: 1003 nurses (74%), 228 physicians (17%), and 128 others (10%). Significantly more positive attitudes toward practice guidelines were found among staff in pediatric compared with adult ICUs (P < .001). Nurses and other staff when compared with physicians had more positive attitudes toward guidelines in general but not toward the specific Hand Hygiene Guideline. Those with more positive attitudes were significantly more likely to report that they had implemented recommendations of the Guideline (P < .001) and used an alcohol product for hand hygiene (P = .002). The majority of staff members were familiar with the Centers for Disease Control and Prevention Hand Hygiene Guideline. Staff attitudes toward practice guidelines varied by type of ICU and by profession, and more positive attitudes were associated with significantly better self-reported guideline implementation. Because differences in staff attitudes might hinder or facilitate their acceptance and adoption of evidence-based practice guidelines, these results may have important implications for the education and/or socialization of ICU staff.

National Healthcare Safety Network (NHSN) Report, data summary for 2006, issued June 2007

This report is a summary of device-associated infections data collected and reported by hospitals participating in the National Healthcare Safety Network (NHSN) from January through December 2006. This report updates previously published data from the National Nosocomial Infections Surveillance (NNIS) system. 1 CDC NNIS System National Nosocomial Infections Surveillance (NNIS) system report, data summary from January 1992 to June 2004, issued October 2004. Am J Infect Control. 2004; 32: 440-485 Google Scholar , 2 Jarvis W.R. Edwards J.R. Culver D.H. Hughes J.M. Horan T. Emori T.G. et al. Nosocomial infection rates in adult and pediatric intensive care units in the United States. Am J Med. 1991; 91: S185-S191 Abstract Full Text PDF PubMed Scopus (444) Google Scholar , 3 Gaynes R.P. Martone W.J. Culver D.H. Emori T.G. Horan T.C. Banerjee S.N. et al. Comparison of rates of nosocomial infections in neonatal intensive care units in the United States. Am J Med. 1991; 91: S192-S196 Abstract Full Text PDF PubMed Scopus (119) Google Scholar

Impact of Collaborative Quality Improvement Project on Incidence and Mortality of Ventilator-Associated Pneumonia in 18 Hospitals in Thailand

Methods During the project, VAP surveillance and prevention were strengthened among 18 participating hospitals. The VAP prevention activities emphasized were placing ventilated patients in a semirecumbent position unless contraindicated, hand hygiene, oral care practices and disinfection of respiratory care equipment. Data were collected among mechanically ventilated patients admitted to the Intensive Care Units (ICU) from May 2004 to February 2005 by Infection Control Nurses (ICN) and trained ICU staff. VAP was diagnosed using pneumonia definition criteria of the National Nosocomial Infection Surveillance System (NNIS) of the Centers for Disease Control and Prevention (CDC) and was confirmed by attending physicians. Data were analyzed using descriptive statistics and Poisson regression.

Increase in the Rate of Sternal Surgical Site Infection After Coronary Artery Bypass Graft: A Marker of Higher Severity of Illness

To evaluate factors related to a gradual rise in sternal surgical site infection (SSI) rates. Retrospective cohort study. A 608-bed, tertiary care teaching hospital. All patients who underwent coronary artery bypass graft (CABG) from January 2000 through September 2004. Of 3,578 patients who underwent CABG, 144 (4%) had sternal SSI. There was an increase in infection rate, with a marked reduction in the number of operations per year. The percentage of patients with peripheral vascular disease increased from 12% to 24.3% (P<.001), and the percentage with congestive heart failure increased from 17% to 22% (P<.001). Between 2002 and 2004, the mean duration of surgery increased from 233 to 290 minutes (P<.001), the percentage of patients with a National Nosocomial Infections Surveillance System (NNIS) risk index of 2 increased from 14.3% to 38% (P<.001), and the percentage of patients with a postoperative stay in the intensive care unit of greater than 72 hours increased from 29% to 40.6% (P<.001). Multivariate analysis showed diabetes mellitus, peripheral vascular disease, obesity, duration of surgery, and postoperative stay in the intensive care unit of greater than 72 hours to be independently associated with infection. An increase in infection in the CABG population not associated with an outbreak may be a reflection of a change in the severity of illness. Preoperative, intraoperative, and postoperative markers for increased infection risk may be used, in addition to the NNIS risk index, to assess the patient population risk.

Nurse Working Conditions and Patient Safety Outcomes

System approaches, such as improving working conditions, have been advocated to improve patient safety. However, the independent effect of many working condition variables on patient outcomes is unknown. To examine effects of a comprehensive set of working conditions on elderly patient safety outcomes in intensive care units. Observational study, with patient outcome data collected using the National Nosocomial Infection Surveillance system protocols and Medicare files. Several measures of health status and fixed setting characteristics were used to capture distinct dimensions of patient severity of illness and risk for disease. Working condition variables included organizational climate measured by nurse survey; objective measures of staffing, overtime, and wages (derived from payroll data); and hospital profitability and magnet accreditation. The sample comprised 15,846 patients in 51 adult intensive care units in 31 hospitals depending on the outcome analyzed; 1095 nurses were surveyed. Central line associated bloodstream infections (CLBSI), ventilator-associated pneumonia, catheter-associated urinary tract infections, 30-day mortality, and decubiti. Units with higher staffing had lower incidence of CLBSI, ventilator-associated pneumonia, 30-day mortality, and decubiti (P <or= 0.05). Increased overtime was associated with higher rates of catheter-associated urinary tract infections and decubiti, but slightly lower rates of CLBSI (P <or= 0.05). The effects of organizational climate and profitability were not consistent. Nurse working conditions were associated with all outcomes measured. Improving working conditions will most likely promote patient safety. Future researchers and policymakers should consider a broad set of working condition variables.

Use of antibacterial agents in an intensive care unit in a hospital in Brazil

It is essential to monitor the utilisation of antibacterial drugs in order to establish appropriate measures for their control. The pattern of usage of antibacterial drugs, and its association with indicators of hospital infection, has been investigated in a non-specialized adult intensive care unit (ICU) located in Santa Luzia Hospital (Brasília, DF, Brazil). The study was conducted between January 2001 and June 2004. Data concerning the utilisation of systemic antibacterial drugs, classified according to the Anatomical Therapeutic Chemical/Defined Daily Dose (ATC/DDD) system, and indicators of hospital infection, defined according to the National Nosocomial Infections Surveillance (NNIS) system, were obtained from appropriate hospital archives. During the study period, the average utilisation of antibacterial drugs was 1918.5 DDD units per 1000 patient-day (DDD(1000)). The three most used drugs were penicillins/beta-lactamase inhibitors (535.3 DDD(1000)), third generation cephalosporins (239.1 DDD(1000)) and quinolones (212.5 DDD(1000)). The total utilisation of antibacterial drugs was correlated significantly with the incidence of hospital infection (R = 0.62; p < 0.01) and the index of invasive procedures (R = 0.41; p < 0.01). Furthermore, the latter two indicators were significantly and positively correlated with the use of recently commercialized, broad spectrum antibacterial drugs (except for carbapenems). It is concluded that improved infection control procedures, together with more rigorous criteria regarding the use of invasive procedures, should be implemented by the ICU studied in order to diminish the utilisation of antibacterial drugs.

Impact of a six-year control programme on surgical site infections in France: results of the INCISO surveillance

Surgical site infections (SSI) are a key target of nosocomial infection control policy. We evaluated the impact of a six-year surveillance system based on data from INCISO, a network of volunteer surgical wards from hospitals in Northern France. Each year surgical patients were enrolled consecutively and surveyed during their in- and out-hospital stay until 30 days following surgery. A standardised form was completed for each patient including SSI diagnosis according to standard criteria and several risk factors such as wound class, American Society of Anesthesiologists score, operation duration, elective/emergency, videoscopy and type of surgery. A dashboard was displayed at the end of each annual survey, so that participants could compare with other surgery adjusted for National Nosocomial Infections Surveillance system (NNIS) risk index and standardised incidence ratio (SIR). Over the six years, 3661 SSI were identified in 150 440 surgical patients (crude incidence: 2.4%) from 548 surgery wards. The crude SSI incidence decreased from 3.8 to 1.7% (P for trend <0.0001, relative reduction: -55%) and the NNIS-0 adjusted SSI incidence from 2.0 to 1% (P for trend <0.0001; relative reduction: -50%). An active surveillance system striving for benchmark through a network is an effective strategy to reduce SSI incidence. Sustaining control efforts have to be made to maintain low SSI level beyond the three primer years.

Prevalence and predictors of surgical site infection in Tbilisi, Republic of Georgia

Surgical site infections (SSIs) are a serious problem worldwide. Little is known about the epidemiology of SSI in the former Soviet Union. In order to determine the prevalence and predictors of SSI in the Republic of Georgia, we undertook a multicentre observational study of SSIs in three urban hospitals in the capital, Tbilisi. Point prevalence studies (PPS) were performed every 3-5 weeks from September 2000 to January 2002 using the National Nosocomial Infections Surveillance (NNIS) System definitions. All patients who had undergone surgery and were present in participating departments at study hospitals on the day of PPS were included. Of 872 surgical procedures, 146 (16.7%) were complicated by SSI. The prevalence of SSI varied by procedure and risk category. On multivariate regression analysis, age, wound class, one hospital (B) and urological surgery were predictive of SSI. In a separate model, NNIS risk index was highly predictive of SSI. Antibiotic prophylaxis was rare (29.5% of operations), while postoperative antibiotic use was common. SSI is an important problem in the Republic of Georgia. Potential areas for intervention include antibiotic prophylaxis and shaving practices for skin preparation.

Nosocomial infection in a neonatal intensive care unit: A prospective study in Taiwan

We performed a prospective analysis to determine the prevalence of nosocomial infection and associated risk factors in our neonatal intensive care unit (NICU). Data were collected prospectively on underlying diagnoses, therapeutic interventions/treatments, infections, and outcomes at 9 am every day from November 2004 through October 2005. Prevalence of nosocomial infection and infection site definitions were according to the National Nosocomial Infections Surveillance system of the Centers for Disease Control and Prevention. Among 528 infants enrolled, 60 (11.4%) had 97 nosocomial infections. The survival rate was 92%. The prevalence of nosocomial infections was 17.5%: bloodstream infection, 4.7%, clinical sepsis, 6.3%, pneumonia, 5.1%, urinary tract infections (UTIs), 0.7%, surgical site infection, 0.7%. Intervention-associated infection rate: central intravascular catheter-associated bloodstream infection, 13.7%, TPN-associated bloodstream infection, 15.8%, ventilator-associated pneumonia, 18.6%, surgical site infection 13.7%, urinary catheter-associated UTI, 17.3%. Cut-off values of onset of central intravascular catheter-associated bloodstream infection and ventilator-associated pneumonia were 6 days and 10 days after intervention, respectively. Patients with a birth weight <1000 g (relative risk, 11.8, 95% confidence interval, 7.66-18.18; P < .001) were at the greatest risk for nosocomial infection. This study revealed the high prevalence of nosocomial infections in NICU patients, and the urgent need for a national surveillance and more effective prevention interventions.

Development of a Surveillance System for Methicillin-ResistantStaphylococcus aureusin German Hospitals

To determine the appropriate method to calculate the rate of methicillin-resistant Staphylococcus aureus (MRSA) infection and colonization (hereafter, MRSA rates) for interhospital comparisons, such that the large number of patients who are already MRSA positive on admission is taken into account. A prospective, multicenter, hospital-based surveillance of MRSA-positive case patients from January through December 2004. Data from 31 hospitals participating in the German national nosocomial infections surveillance system (KISS) were recorded during routine surveillance by the infection control team at each hospital. Data for 4,215 MRSA-positive case patients were evaluated. From this data, the following values were calculated. The median incidence density was 0.71 MRSA-positive case patients per 1,000 patient-days, and the median nosocomial incidence density was 0.27 patients with nosocomial MRSA infection or colonization per 1,000 patient-days (95% CI, 0.18-0.34). The median average daily MRSA burden was 1.13 MRSA patient-days per 100 patient-days (95% CI, 0.86-1.51), with the average daily MRSA burden defined as the total number of MRSA patient-days divided by the total number of patient-days times 100. The median MRSA-days-associated nosocomial MRSA infection and colonization rate, which describes the MRSA infection risk for other patients in hospitals housing large numbers of MRSA-positive patients and/or many patients who were MRSA positive on admission, was 23.1 cases of nosocomial MRSA infection and colonization per 1,000 MRSA patient-days (95% CI, 17.4-28.6). The values were also calculated for various MRSA screening levels. The MRSA-days-associated nosocomial MRSA rate allows investigators to assess the extent of MRSA colonization and infection at each hospital, taking into account cases that have been imported from other hospitals, as well as from the community. This information provides an appropriate incentive for hospitals to introduce further infection control measures.

Risk Adjustment for Surgical Site Infection After Median Sternotomy in Children

To determine whether the National Nosocomial Infections Surveillance (NNIS) System risk index adequately stratified a population of pediatric patients undergoing cardiac surgery according to the risk of developing surgical site infection (SSI). A retrospective, case-control study. An urban tertiary care children's hospital. Patients who had a median sternotomy performed between January 1, 1995, and December 31, 2003, were eligible for inclusion in the study. For all case patients, medical records were reviewed to verify that all patients met the case definition for SSI. Control subjects were chosen randomly from among all patients who underwent median sternotomy during the study period who did not develop SSI. Thirty-eight patients with SSI and 172 patients without SSI were included. One hundred six patients (50%) were male. The median patient age was 4 months. The sensitivity of the NNIS risk index with cutoff scores of 0 to 1 and 2 to 3 was 20%. The distribution of patients with SSI for an NNIS risk index score of 0 was 0%; for a score of 1, 80%; for a score of 2, 20%; and for a score of 3, 0%. The distribution of patients without SSI for a scores of 0 was 4%; for a score of 1, 87%; for a score of 2, 9%; and for a score of 3, 0%. The area under the receiver-operating characteristic curve (AUC) of the original NNIS risk index was 0.57. The modified risk indices did not perform significantly better, with an AUC range of 0.58 to 0.73. The NNIS risk index did not adequately stratify pediatric patients undergoing median sternotomy according to their risk of developing an SSI. Various modifications to the risk index yielded only slightly higher AUC values.