The National Nosocomial Infections Surveillance System: plans for the 1990s and beyond

Data quality review of the Brazilian nosocomial infections surveillance system

BACKGROUND

Surveillance of healthcare-associated infections (HAIs) is an essential component of hospital infection prevention and control systems. We aimed to assess the quality of the data compiled by the Brazilian HAI Surveillance System from pediatric (PICUs) and neonatal intensive care units (NICUs), between 2012 and 2021.

METHODS

Data Quality Review, including adherence, completeness, internal consistency, consistency over time, and consistency of population trend, were computed at both national and state levels based on quality metrics from World Health Organization Toolkit. Incidence rates (or incidence density) of ventilator-associated pneumonia (VAP) and central line-associated bloodstream infection (CLABSI) were obtained from the Brazilian National Nosocomial Infections Surveillance (NNIS) system. Data on sepsis-related mortality, spanning the period from 2012 to 2021, were extracted from the Brazilian National Health Service database (DATASUS). Additionally, correlations between sepsis-related mortality and incidence rates of VAP or CLABSI were calculated.

RESULTS

Throughout the majority of the study period, adherence to VAP reporting remained below 75%, exhibiting a positive trend post-2016. Widespread outliers, as well as inconsistencies over time and in population trends, were evident across all 27 states. Only four states maintained consistent adherence levels above 75% for more than 8 years regarding HAI incidence rates. Notably, CLABSI in NICUs boasted the highest reporting adherence among all HAIs, with 148 periods out of 270 (54.8%) exhibiting reporting adherence surpassing 75%. Three states achieved commendable metrics for CLABSI in PICUs, while five states demonstrated favorable results for CLABSI in NICUs.

CONCLUSIONS

While adherence to HAI report is improving among Brazilian states, an important room for improvement in the Brazilian NNIS exists. Additional efforts should be made by the Brazilian government to improve the reliability of HAI data, which could serve as valuable guidance for hospital infection prevention and control policies.

Awareness and wound assesment decrease surgical site infections

Objective: Various surveillance methods have been described for surveillance of surgical site infections (SSI). The aim of this study was to examine prac- ticality of SSI risk assessment methods (SENIC and NNIS) with a postoperative wound monitoring scale (ASEPSIS) as an outcome assessment measure and evaluation of the contribution of wound assesment to the reduction of wound infection.

Material and Methods: Patients were followed with a prospective data chart through four year. Correlation of SENIC and NNIS together with ASEPSIS were performed.

Results: During the study period, 275 SSI occurred. SSIs were determined within the 21 days-period after operations. Correlation between SENIC with ASEPSIS (rs= 0.41, p< 0.001) was found better than that for NNIS with ASEPSIS (rs= 0.37, p< 0.001). Type of operation (emergency vs. elective), body mass index, operation class and American Society of Anesthesiologists scores were found independently predictive factors for SSI. The forth year SSI rate was found to be significantly lower than the other years (p< 0.001).

Conclusion: This study indicates weak but significant correlation between preoperative risk assessment methods for SSI and ASEPSIS method. In addi- tion, surgical wound assesment and awarness of the wound infection rates, have decreased the SSI rates over the years.

Population-Based Active Surveillance for Culture-Confirmed Candidemia - Four Sites, United States, 2012-2016

PROBLEM/CONDITION

Candidemia is a bloodstream infection (BSI) caused by yeasts in the genus Candida. Candidemia is one of the most common health care-associated BSIs in the United States, with all-cause in-hospital mortality of up to 30%.

PERIOD COVERED

2012-2016.

DESCRIPTION OF SYSTEM

CDC's Emerging Infections Program (EIP), a collaboration among CDC, state health departments, and academic partners that was established in 1995, was used to conduct active, population-based laboratory surveillance for candidemia in 22 counties in four states (Georgia, Maryland, Oregon, and Tennessee) with a combined population of approximately 8 million persons. Laboratories serving the catchment areas were recruited to report candidemia cases to the local EIP program staff. A case was defined as a blood culture that was positive for a Candida species collected from a surveillance area resident during 2012-2016. Isolates were sent to CDC for species confirmation and antifungal susceptibility testing. Any subsequent blood cultures with Candida within 30 days of the initial positive culture in the same patient were considered part of the same case. Trained surveillance officers collected clinical information from the medical chart for all cases, and isolates were sent to CDC for species confirmation and antifungal susceptibility testing.

RESULTS

Across all sites and surveillance years (2012-2016), 3,492 cases of candidemia were identified. The crude candidemia incidence averaged across sites and years during 2012-2016 was 8.7 per 100,000 population; important differences in incidence were found by site, age group, sex, and race. The crude annual incidence was the highest in Maryland (14.1 per 100,000 population) and lowest in Oregon (4.0 per 100,000 population). The crude annual incidence of candidemia was highest among adults aged ≥65 years (25.5 per 100,000 population) followed by infants aged <1 year (15.8). The crude annual incidence was higher among males (9.4) than among females (8.0) and was approximately 2 times greater among blacks than among nonblacks (13.7 versus 5.8). Ninety-six percent of cases occurred in patients who were hospitalized at the time of or during the week after having a positive culture. One third of cases occurred in patients who had undergone a surgical procedure in the 90 days before the candidemia diagnosis, 77% occurred in patients who had received systemic antibiotics in the 14 days before the diagnosis, and 73% occurred in patients who had had a central venous catheter (CVC) in place within 2 days before the diagnosis. Ten percent were in patients who had used injection drugs in the past 12 months. The median time from admission to candidemia diagnosis was 5 days (interquartile range [IQR]: 0-16 days). Among 2,662 cases that were treated in adults aged >18 years, 34% were treated with fluconazole alone, 30% with echinocandins alone, and 34% with both. The all-cause, in-hospital case-fatality ratio was 25% for any time after admission; the all-cause in-hospital case-fatality ratio was 8% for <48 hours after a positive culture for Candida species. Candida albicans accounted for 39% of cases, followed by Candida glabrata (28%) and Candida parapsilosis (15%). Overall, 7% of isolates were resistant to fluconazole and 1.6% were resistant to echinocandins, with no clear trends in resistance over the 5-year surveillance period.

INTERPRETATION

Approximately nine out of 100,000 persons developed culture-positive candidemia annually in four U.S. sites. The youngest and oldest persons, men, and blacks had the highest incidences of candidemia. Patients with candidemia identified in the surveillance program had many of the typical risk factors for candidemia, including recent surgery, exposure to broad-spectrum antibiotics, and presence of a CVC. However, an unexpectedly high proportion of candidemia cases (10%) occurred in patients with a history of injection drug use (IDU), suggesting that IDU has become a common risk factor for candidemia. Deaths associated with candidemia remain high, with one in four cases resulting in death during hospitalization.

PUBLIC HEALTH ACTION

Active surveillance for candidemia yielded important information about the disease incidence and death rate and persons at greatest risk. The surveillance was expanded to nine sites in 2017, which will improve understanding of the geographic variability in candidemia incidence and associated clinical and demographic features. This surveillance will help monitor incidence trends, track emergence of resistance and species distribution, monitor changes in underlying conditions and predisposing factors, assess trends in antifungal treatment and outcomes, and be helpful for those developing prevention efforts. IDU has emerged as an important risk factor for candidemia, and interventions to prevent invasive fungal infections in this population are needed. Surveillance data documenting that approximately two thirds of candidemia cases were caused by species other than C. albicans, which are generally associated with greater antifungal resistance than C. albicans, and the presence of substantial fluconazole resistance supports 2016 clinical guidelines recommending a switch from fluconazole to echinocandins as the initial treatment for candidemia in most patients.

Standardized Infection Surveillance in Long-Term Care Interfacility Comparisons From a Regional Cohort of Facilities

Objectives:

To measure infection rates in a regional cohort of long-term-care facilities (LTCFs) using standard surveillance methods and to analyze different methods for interfacility comparisons.

Setting:

Seventeen LTCFs in Idaho.

Design:

Prospective, active surveillance for LTCF-acquired infections using standard definitions and case-finding methods was conducted from July 2001 to June 2002. All surveillance data were combined and individual facility performance was compared with the aggregate employing a variety of statistical and graphic methods.

Results:

The surveillance data set consisted of 472,019 resident-days of care with 1,717 total infections for a pooled mean rate of 3.64 infections per 1,000 resident-days. Specific infections included respiratory (828; rate, 1.75), skin and soft tissue (520; rate, 1.10), urinary tract (282; rate, 0.60), gastrointestinal (77; rate, 0.16), unexplained febrile illnesses (6; rate, 0.01), and bloodstream (4; rate, 0.01). Initially, methods adopted from the National Nosocomial Infections Surveillance System were used comparing individual rates with pooled means and percentiles of distribution. A more sensitive method appeared to be detecting statistically significant deviations (based on chi-square analysis) of the individual facility rates from the aggregate of all other facilities. One promising method employed statistical process control charts (U charts) adjusted to compare individual rates with aggregate monthly rates, providing simultaneous visual and statistical comparisons. Small multiples graphs were useful in providing images valid for rapid concurrent comparison of all facilities.

Conclusion:

Interfacility comparisons have been demonstrated to be valuable for hospital infection control programs, but have not been studied extensively in LTCFs.

Infection surveillance systems in primary health care: A literature review

The Patient Protection and Affordable Care Act of 2010 is placing primary care at the epicenter of accountability of US health care delivery. There is a significant body of evidence characterizing the value of acute-care hospital infection surveillance systems. Given the central role primary care is beginning to play, we were interested in examining the use of infection surveillance systems in primary care practice. Our review of the literature found only 2 articles describing the influence of primary care infection surveillance systems, both providing evidence of its benefits. This area is ripe for further research.

Outbreak of Hemodialysis Vascular Access Site Infections Related to Malfunctioning Permanent Tunneled Catheters: Making the Case for Active Infection Surveillance

Objective:

To describe an outbreak of infections with permanent cuffed hemodialysis catheters recognized through ongoing surveillance and related to a specific malfunctioning permanent catheter.

Design:

The outbreak was suspected from the results of prospective infection surveillance and confirmed by a retrospective cohort study using medical records for patients receiving dialysis between April 1,1999, and March 31, 2000.

Setting:

Integrated network of six outpatient hemodialysis facilities in southern Idaho and eastern Oregon.

Patients:

Outpatients receiving long-term hemodialysis.

Results:

During the 18 months prior to the outbreak, the overall infection rate was 4.1 infections per 1,000 dialysis sessions with a catheter rate of 8.9 per 1,000 dialysis sessions. During the 7 months of the outbreak, the overall rate increased to 5.8 per 1,000 dialysis sessions, whereas the catheter rate increased to 18.1 per 1,000 dialysis sessions. Reports of malfunctioning “Brand A” catheters prompted discontinuation of their placement. A manufacturer recall occurred in April 2000. During the 14 months after the outbreak, the overall infection rate decreased to 3.3 per 1,000 dialysis sessions and the catheter rate to 10.8 per 1,000 dialysis sessions. A 12-month retrospective cohort study recognized 96 patients with an identifiable catheter brand and 48 infections. Of these, 27 (56%) occurred in patients with Brand A catheters. The relative risk for infection when compared with other catheter brands was 1.96 (95% confidence interval, 1.32 to 2.92; P < .001).

Conclusions:

Ongoing infection surveillance in hemodialysis facilities can identify specific device-related outbreaks of infections and promote interventions to reduce infectious complications and promote patient safety. Surveillance for vascular access site infections is recommended as a routine activity in hemodialysis facilities.

Attributable Cost and Length of Stay for Patients With Central Venous Catheter—Associated Bloodstream Infection in Mexico City Intensive Care Units A Prospective, Matched Analysis

Background.

No information is available about the financial impact of central venous catheter (CVC)-associated bloodstream infection (BSI) in Mexico.

Objective.

To calculate the costs associated with BSI in intensive care units (ICUs) in Mexico City.

Design.

An 18-month (June 2002 through November 2003), prospective, nested case-control study of patients with and patients without BSI.

Setting.

Adult ICUs in 3 hospitals in Mexico City.

Patients and Methods.

A total of 55 patients with BSI (case patients) and 55 patients without BSI (control patients) were compared with respect to hospital, type of ICU, year of hospital admission, length of ICU stay, sex, age, and mean severity of illness score. Information about the length of ICU stay was obtained prospectively during daily rounds. The daily cost of ICU stay was provided by the finance department of each hospital. The cost of antibiotics prescribed for BSI was provided by the hospitals' pharmacy departments.

Results.

For case patients, the mean extra length of stay was 6.1 days, the mean extra cost of antibiotics was $598, the mean extra hospital cost was $11,591, and the attributable extra mortality was 20%.

Conclusions.

In this study, the duration of ICU stay for patients with central venous catheter-associated BSI was significantly longer than that for control patients, resulting in increased healthcare costs and a higher attributable mortality. These conclusions support the need to implement preventive measures for hospitalized patients with central venous catheters in Mexico.

Validation of statewide surveillance system data on central line-associated bloodstream infection in intensive care units in Australia

OBJECTIVE

To measure the interobserver agreement, sensitivity, specificity, positive predictive value, and negative predictive value of data submitted to a statewide surveillance system for identifying central line-associated bloodstream infection (BSI).

DESIGN

Retrospective review of hospital medical records comparing reported data with gold standard according to definitions of central line-associated BSI.

SETTING

Six Victorian public hospitals with more than 100 beds.

METHODS

Reporting of surveillance outcomes was undertaken by infection control practitioners at the hospital sites. Retrospective evaluation of the surveillance process was carried out by independent infection control practitioners from the Victorian Hospital Acquired Infection Surveillance System (VICNISS). A sample of records of patients reported to have a central line-associated BSI were assessed to determine whether they met the definition of central line-associated BSI. A sample of records of patients with bacteremia in the intensive care unit during the assessment period who were not reported as having central line-associated BSI were also assessed to see whether they met the definition of central line-associated BSI.

RESULTS

Records of 108 patients were reviewed; the agreement between surveillance reports and the VICNISS assessment was 67.6% (k = 0.31). Of the 46 reported central line-associated BSIs, 27 were confirmed to be central line-associated BSIs, for a positive predictive value of 59% (95% confidence interval [CI], 43%-73%). Of the 62 cases of bacteremia reviewed that were not reported as central line-associated BSIs, 45 were not associated with a central line, for a negative predictive value of 73% (95% CI, 60%-83%). Estimated sensitivity was 35%, and specificity was 87%. The positive likelihood ratio was 3.0, and the negative likelihood ratio was 0.72.

DISCUSSION

The agreement between the reporting of central line-associated BSI and the gold standard application of definitions was unacceptably low. False-negative results were problematic; more than half of central line-associated BSIs may be missed in Victorian public hospitals.

Correlation of risk and postoperative assessment methods in wound surveillance

BACKGROUND

Various surveillance methods have been described for surveillance of surgical site infections (SSI). The aim of this study was to examine practicality of SSI risk assessment methods (Study on the Efficacy of Nosocomial Infection Control [SENIC] and National Nosocomial Infections Surveillance [NNIS]) with a postoperative wound monitoring scale (ASEPSIS) as an outcome assessment measure.

MATERIALS AND METHODS

Patients were followed with a prospective data chart from January 1, 2003, to December 31, 2005. Correlation of SENIC and NNIS together with ASEPSIS were performed.

RESULTS

During the study period, 222 SSI occurred. SSIs were determined within the 21-d period after operations. Correlation between SENIC with ASEPSIS (r(s) = 0.47, P < 0.001) was found better than that for NNIS with ASEPSIS (r(s) = 0.41, P < 0.001). Type of operation (emergency versus elective), body mass index, operation class, and American Society of Anesthesiologists scores were found independently predictive factors for SSI.

CONCLUSIONS

This study indicates weak but significant correlation between preoperative risk assessment methods for SSI and ASEPSIS.

Administrative coding data, compared with CDC/NHSN criteria, are poor indicators of health care-associated infections

BACKGROUND

ICD-9-CM coding alone has been proposed as a method of surveillance for health care-associated infections (HAIs). The accuracy of this method, however, relative to accepted infection control criteria is not known.

METHODS

Retrospective analysis of patients at an academic medical center in 2005 who underwent surgical procedures or who were at risk for catheter-associated bloodstream infections or ventilator-associated pneumonia was performed. Patients previously identified with HAIs by Centers for Disease Control and Prevention's National Healthcare Safety Network surveillance methods were compared with those of the same risk group identified by secondary infection ICD-9-CM codes. Discordant cases identified by only coding were all rereviewed and adjusted prior to final analysis. When coding and surveillance were both negative, a sample of patients was used to estimate the proportion of false negatives in this group.

RESULTS

The positive predictive values (PPVs) ranged from 0.14 to 0.51 with an aggregate of 0.23, even after adjustment for additional cases detected on subsequent medical record review. The negative predictive values (NPVs) ranged from 0.91 to 1.00, with an aggregate of 0.96. The estimates of the true variance of PPVs and NPVs across surgical procedures were small (0.0129, standard error, 0.009; 0.000145, standard error, 0.00019, respectively) and could be mostly explained by variation in prevalence of surgical site infections.

CONCLUSION

Administrative coding alone appears to be a poor tool to be used as an infection control surveillance method. Its proposed use for routine HAI surveillance, public reporting of HAIs, interfacility comparisons, and nonpayment for performance should be seriously questioned.

An enhanced benchmark for prosthetic joint replacement infection rates

BACKGROUND

The National Nosocomial Infection Surveillance System (NNIS) has historically provided the infection control community with the most accurate benchmark for healthcare-associated infections. However, NNIS does not require postdischarge surveillance. For medical centers where comprehensive postdischarge surveillance is possible, the efficiency of surgical site infection (SSI) detection is enhanced and rates may be higher than those provided by NNIS.

METHODS

From 1999 to 2004, a large integrated healthcare system (IHCS) used a standard surveillance methodology inclusive of the postdischarge period. This article compares IHCS and NNIS SSI data.

RESULTS

IHCS infection rates, stratified and weighted average (hip, 1.7; knee, 2.1) for the study period are higher than the corresponding NNIS rates (hip, 1.4; knee, 1.2) (hip, P = .006; knee, P = .012) when infections detected by the IHCS during the postdischarge period are included.

CONCLUSIONS

The data from the study period show that when comprehensive postdischarge surveillance is used by the IHCS, SSI rates are higher than those reflected in the NNIS database.

Burn wound infections

Burns are one of the most common and devastating forms of trauma. Patients with serious thermal injury require immediate specialized care in order to minimize morbidity and mortality. Significant thermal injuries induce a state of immunosuppression that predisposes burn patients to infectious complications. A current summary of the classifications of burn wound infections, including their diagnosis, treatment, and prevention, is given. Early excision of the eschar has substantially decreased the incidence of invasive burn wound infection and secondary sepsis, but most deaths in severely burn-injured patients are still due to burn wound sepsis or complications due to inhalation injury. Burn patients are also at risk for developing sepsis secondary to pneumonia, catheter-related infections, and suppurative thrombophlebitis. The introduction of silver-impregnated devices (e.g., central lines and Foley urinary catheters) may reduce the incidence of nosocomial infections due to prolonged placement of these devices. Improved outcomes for severely burned patients have been attributed to medical advances in fluid resuscitation, nutritional support, pulmonary and burn wound care, and infection control practices.

Burn wound infections

Burns are one of the most common and devastating forms of trauma. Patients with serious thermal injury require immediate specialized care in order to minimize morbidity and mortality. Significant thermal injuries induce a state of immunosuppression that predisposes burn patients to infectious complications. A current summary of the classifications of burn wound infections, including their diagnosis, treatment, and prevention, is given. Early excision of the eschar has substantially decreased the incidence of invasive burn wound infection and secondary sepsis, but most deaths in severely burn-injured patients are still due to burn wound sepsis or complications due to inhalation injury. Burn patients are also at risk for developing sepsis secondary to pneumonia, catheter-related infections, and suppurative thrombophlebitis. The introduction of silver-impregnated devices (e.g., central lines and Foley urinary catheters) may reduce the incidence of nosocomial infections due to prolonged placement of these devices. Improved outcomes for severely burned patients have been attributed to medical advances in fluid resuscitation, nutritional support, pulmonary and burn wound care, and infection control practices.

Gender risk differences for surgical site infections among a primary coronary artery bypass graft surgery cohort: 1995-1998

BACKGROUND

Knowledge about gender risk factors associated with acquiring postoperative coronary artery bypass graft (CABG) surgical site infections (SSIs) is limited.

OBJECTIVE

Our objective was to determine whether the incidence of SSIs during 30 days postsurgery was greater among females compared with males who undergo primary (first time) CABG.

METHODS

A retrospective cohort study of 3878 patients who had primary CABG surgery between January 1, 1995, and December 31, 1998, at a cardiovascular center in the American Southwest. Multivariate techniques were used to analyze outcome risk differences by gender.

RESULTS

The nosocomial SSI incidence rate among 957 females was 10.56%; among 2921 males, it was 7.57%; relative risk (RR) was 1.39 (95% confidence interval: 1.12-1.75), and Mantel-Haenszel chi2 test was 8.47 (P = .004). Four preoperative variables were independent predictors of acquiring SSI: female gender, diabetes, body mass index, and urgency of surgery.

CONCLUSION

Females were at greater risk for acquiring SSIs postprimary CABG surgery in this cohort. Also, preoperative, perioperative, and postoperative control of glucose levels in diabetics and preoperative reduction of weight in obese patients may help to reduce SSIs post-CABG surgery. More studies are needed to understand gender-associated risk of SSI after CABG surgery.

Assessment of the value of repeated point-prevalence surveys for analyzing the trend in nosocomial infections

OBJECTIVE

To assess the value of repeated point-prevalence surveys in measuring the trend in nosocomial infections after adjustment for case mix.

SETTING

A 3,500-bed teaching facility composed of 4 acute care hospitals.

METHODS

From May 1992 to June 1996, eight point-prevalence surveys of nosocomial infections were performed in the hospitals using a sampling process. The trend of adjusted nosocomial infection rates was studied for the four surveys that collected data on indwelling catheters. Adjusted rates were calculated using a logistic regression model and a direct standardization method.

RESULTS

From 1992 to 1996, a total of 20,238 patients were included in the 8 point-prevalence surveys. The nosocomial infection rate decreased from 8.6% in 1992 to 5% in 1996 (P < .001). The analysis of adjusted nosocomial infection rates included 9,600 patients. Four independent risk factors were identified: length of stay greater than 12 days, hospitalization in an intensive care unit, presence of an indwelling urinary catheter, and history of a surgical procedure. After adjustment for case mix, the nosocomial infection rate still showed a downward trend (from 7.2% in 1993 to 5.1% in 1996; P = .02).

CONCLUSION

Adjusted prevalence rates of nosocomial infections showed a significant downward trend during the period of this study.

The attributable cost and length of hospital stay because of nosocomial pneumonia in intensive care units in 3 hospitals in Argentina: a prospective, matched analysis

BACKGROUND

No information is available on the financial impact of nosocomial pneumonia in Argentina. To calculate the cost of nosocomial pneumonia in intensive care units, a 5-year, matched cohort study was undertaken at 3 hospitals in Argentina.

SETTING

Six adult intensive care units (ICU).

METHODS

Three hundred seven patients with nosocomial pneumonia (exposed) and 307 patients without nosocomial pneumonia (unexposed) were matched for hospital, ICU type, year admitted to study, length of stay more than 7 days, sex, age, antibiotic use, and average severity of illness score (ASIS). The patient's length of stay (LOS) in the ICU was obtained prospectively in daily rounds, the cost of a day was provided by the hospital's finance department, and the cost of antibiotics prescribed for nosocomial pneumonia was provided by the hospital's pharmacy department.

RESULTS

The mean extra LOS for 307 cases (compared with controls) was 8.95 days, the mean extra antibiotic defined daily doses (DDD) was 15, the mean extra antibiotic cost was $996, the mean extra total cost was $2255, and the extra mortality was 30.3%.

CONCLUSIONS

Nosocomial pneumonia results in significant patient morbidity and consumes considerable resources. In the present study, patients with nosocomial pneumonia had significant prolongation of hospitalization, cost, and a high extra mortality. The present study illustrates the potential cost savings of introducing interventions to reduce nosocomial pneumonia. To our knowledge, this is the first study evaluating this issue in Argentina.

[Electronic surveillance of nosocomial infections in head and neck surgery and stapes surgery]

BACKGROUND

Nosocomial infection is generally regarded as the most important postoperative complication. Therefore, on 28 December 2002 a German law was implemented requiring the surveillance of postoperative infections in all hospitals.

METHODS

The authors propose using stapes and thyroid surgery to monitor the infection rate in a typical Head and Neck Department. A versatile software (CISS) based on MS Word and MS Excel was developed for this purpose.

RESULTS

Postoperative infections were retrospectively analyzed for three subsequent years. The present data confirm the results of previous studies that surveillance itself is a powerful tool in reducing the postoperative infection rate.

CONCLUSION

The newly developed software provided an easy tool for the collection of infection data. The reported infection rates in stapes and thyroid surgery are representative of ENT clinics in Germany.

Assessing the status of infection control programs in small rural hospitals in the western United States

BACKGROUND

Organized infection control (IC) interventions have been successful in reducing the acquisition of hospital-associated infections. Rural community hospitals, although contributing significantly to the US health care system, have rarely been assessed regarding the nature and quality of their IC programs.

METHODS

A sample of 77 small rural hospitals in Idaho, Nevada, Utah, and eastern Washington completed a written survey in 2000 regarding IC staffing, infrastructure support, surveillance of nosocomial infections, and IC policies and practices.

RESULTS

Almost all hospitals (65 of 67, 97%) had one infection control practitioner (ICP), and 29 of 61 hospitals (47.5%) reported a designated physician with IC oversight. Most ICPs (62 of 64, 96.9%) were also employed for other activities outside of IC. The median number of ICP hours per week for IC activities was 10 (1-40), equating to a median of 1.56 (0.30-21.9) full-time ICPs per 250 hospital beds. Most hospitals performed total house surveillance for nosocomial infections (66 of 73, 90.4%) utilizing Centers for Disease Control and Prevention (CDC) definitions (69 of 74, 93.2%). Most also monitored employee bloodborne exposures (69 of 73, 94.5%). All hospitals had a written bloodborne pathogen exposure plan and isolation policies. CDC guidelines were typically followed when developing IC policies. Access to medical literature and online resources appeared to be limited for many ICPs.

CONCLUSIONS

Most rural hospitals surveyed have expended reasonable resources to develop IC programs that are patterned after those seen in larger hospitals and conform to recommendations of consensus expert panels. Given these hospitals' small patient census, short length of stay, and low infection rates, further studies are needed to evaluate necessary components of effective IC programs in these settings that efficiently utilize limited resources without compromising patient care.

Effect of education and performance feedback on rates of catheter-associated urinary tract infection in intensive care units in Argentina

OBJECTIVE

To evaluate the effect of education and performance feedback regarding compliance with catheter care and handwashing on rates of catheter-associated urinary tract infection (UTI) in intensive care units (ICUs).

SETTING

Two level III adult ICUs in a private healthcare facility in Argentina.

PATIENTS

All adult patients admitted to the study units who had a urinary catheter in place for at least 24 hours.

METHODS

A prospective, open trial in which rates of catheter-associated UTI determined during a baseline period of active surveillance without education and performance feedback were compared with rates of catheter-associated UTI after implementing education and performance feedback.

RESULTS

There were 1,779 catheter-days during the baseline period and 5,568 catheter-days during the intervention period. Compliance regarding prevention of compression of the tubing by a leg improved (from 83% to 96%; relative risk [RR], 1.15; 95% confidence interval [CI95], 1.03 to 1.28; P = .01) and so did compliance with handwashing (from 23.1% to 65.2%; RR, 2.82; CI95, 2.49 to 3.20; P < .0001). Catheter-associated UTI rates decreased significantly from 21.3 to 12.39 per 1,000 catheter-days (RR, 0.58; CI%, 0.39 to 0.86; P = .006).

CONCLUSION

Implementing education and performance feedback regarding catheter care measures and handwashing compliance was associated with a significant reduction in catheter-associated UTI rates. Similar programs may help reduce catheter-associated UTI rates in other Latin American hospitals.

Uso de diagramas de controle na vigilância epidemiológica das infecções hospitalares

OBJETIVO: Monitorizar a tendência de ocorrência e identificar surtos de infecções hospitalares utilizando diagramas de controles. MÉTODOS: No período de janeiro de 1998 a dezembro de 2000, a ocorrência de infecções hospitalares foi avaliada em uma coorte de 460 pacientes, internados em uma Unidade de Terapia Intensiva Pediátrica de um hospital universitário, segundo os conceitos e critérios da metodologia do sistema "National Nosocomial Infection Surveillance", do "Centers for Disease Control" (EUA). Os gráficos foram construídos de acordo com a distribuição probabilística de Poisson. Quatro linhas horizontais foram plotadas. A linha central foi representada pela incidência média das infecções hospitalares no período estudado e as linhas de alerta superior e de controle superior foram calculadas a partir de dois e três desvios-padrão acima da incidência média das infecções hospitalares, respectivamente. Os surtos de infecção hospitalar foram identificados quando sua incidência mensal permaneceu acima da linha do limite de controle superior. RESULTADOS: A incidência média de infecções hospitalares por mil pacientes dia foi de 20. Um surto de infecção do trato urinário foi identificado em julho de 2000, cuja taxa de infecção foi de 63 por mil pacientes dia, ultrapassando a linha de controle superior, configurando um período epidêmico. CONCLUSÕES: A utilização dos diagramas de controle do nível endêmico, tanto por avaliação global e sítio específica, possibilitou identificar e distinguir das variações naturais nas taxas de ocorrência de infecções hospitalares aquelas de causas incomuns, como os surtos ou epidemias, dispensando o uso de cálculos e testes de hipóteses.

A prospective study of hemodialysis access-related bacterial infections

The objective of this study was to describe hemodialysis vascular-access related infections that occurred in hemodialysis patients over an 18-month period. The study is a prospective descriptive analysis of incidence infection rates in a hemodialysis unit in a tertiary-care medical center. Prospective surveillance for hemodialysis vascular access-related infection was performed for all patients undergoing hemodialysis from November 1999 through April 2001 at King Fahd Hospital of King Faisal University, Al-Khobar, Saudi Arabia. The total number of dialysis sessions was calculated. The type of vascular access was noted. Cultures were obtained and all infections were recorded and infection rates were calculated. There were 9627 hemodialysis sessions (5437 via permanent fistulae or grafts, 2409 via temporary central catheters, and 1781 via permanent tunneled catheters) during the 18-month study period. We identified a total of 109 infections, for a rate of 11.32/1000 dialysis sessions (ds). Of the 109, 23 involved permanent fistulae or grafts (4.23/1000 ds); 18 involved permanent-tunneled central catheter infections (10.1/1000 ds); and 68 involved temporary-catheter infections (28.23/1000 ds). There were 38 bloodstream infections (3.95/1000 ds) and 34 episodes of clinical sepsis (3.53/1000 ds). Seventy-one vascular access infections without bacteremia were identified (7.38/1000 ds), including 16 permanent-fistulae or graft infections (2.94/1000 ds), 7 permanent-tunneled central catheter infections (3.93/1000 ds), and 48 temporary-catheter infections (19.92/1000 ds). Staphylococcal organisms were responsible for 77% of the infections, with Staphylococcus epidermidis being the strain most commonly implicated. Gram-negative organisms were responsible for 23% of the infections. In conclusion, infection rates were highest in hemodialysis patients with temporary vascular access, compared with rates in those with permanent arteriovenous fistulae and synthetic grafts. Most of the bacterial organisms isolated from the vascular access sites were gram-positive cocci, with S. epidermidis accounting for 50% of the organisms. The rate of infection with gram-negative bacilli was higher than in other reports. Our greater dependence on central venous catheters, due to local factors, coupled with the immune-compromising comorbid conditions of our patients, may be contributory to the pattern of infection reported. Delays in the creation of vascular grafts for hemodialysis access should be avoided.

Surveillance as a starting point to reduce surgical-site infection rates in elective orthopaedic surgery

A surveillance programme was started after a period of high infection rates in an orthopaedic surgical department. The programme was aimed at reducing infection rates in elective hip and knee replacement procedures, and at creating awareness of infection control practices in an acute hospital. Possible causes of the initial high infection rates were analysed and discussed with healthcare workers involved in orthopaedic surgery. No specific cause could be found but substantial logistic improvements were achieved by studying for five years that may have contributed to the reduction of postoperative infections. Surveillance is an important part of any hospital-acquired infection surveillance programme. Its success depends on the ability of the infection control practitioner (ICP) to form a partnership with the surgical staff. Creating a sense of ownership of the surveillance initiative amongst the surgical staff enhances co-operation and ensures that the best use is made of the information generated. It is not possible to eliminate surgical-site infections (SSI) completely, but by a process of sharing information we have been able to influence behaviour to reduce the incidence of SSI.

A prospective study of infections in burn patients

In a 3-year prospective study, all infections presenting in the burns unit of a university hospital were registered in a specially designed database. Two-hundred and thirty adult patients were included. Eighty-three patients had in all 176 infections, giving an infection rate of 48 per 1000 patient days including both nosocomial and community-acquired infections. Thirty-five blood-stream infections (BSI) occurred in 22 patients; most common micro-organisms were coagulase-negative staphylococci and methicillin-sensitive Staphylococcus aureus. The device-specific BSI rate was 6 per 1000 central venous catheter days, which is low compared to other burn units. The pneumonia rate was 41 per 1000 ventilator days. Seventy-two patients had 107 burn wound infections. Antibiotics were given to only 50% of the burn patients, including 96% of the patients with infection and 26% of those without infection. Most frequently used antimicrobials were cloxacillin, penicillin and gentamicin. The antibiotic resistance rates were low, and multi-resistant bacteria or fungi were rare. The database can be used to evaluate the effects of changes in burn treatment, staffing and design of burn units, and antimicrobial resistance development in relation to antibiotic usage.

The direct cost and incidence of systemic fungal infections

OBJECTIVES

In this study we determined the incidence and direct inpatient and outpatient costs of systemic fungal infections (candidiasis, aspergillosis, cryptococcosis, histoplasmosis) in 1998.

METHODS

Using primarily the National Hospital Discharge Survey (NHDS) for incidence and the Maryland Hospital Discharge Data Set (MDHDDS) for costs, we surveyed four systemic fungal infections in patients who also had HIV/AIDS, neoplasia, transplant, and all other concomitant diagnoses. Using a case-control method, we compared the cases with controls (those without fungal infections with the same underlying comorbidity) to obtain the incremental hospitalization costs. We used the Student's t-test to determine significance of incremental hospital costs. We modeled outpatient costs on the basis of discharge status to calculate the total annual cost for systemic fungal infections in 1998.

RESULTS

For 1998, the projected average incidence was 306 per million US population, with candidiasis accounting for 75% of cases. The estimated total direct cost was $2.6 billion and the average per-patient attributable cost was $31,200. The most commonly reported comorbid diagnoses with fungal infections (HIV/AIDS, neoplasms, transplants) accounted for only 45% of all infections.

CONCLUSIONS

The cost burden is high for systemic fungal infections. Additional attention should be given to the 55% with fungal disease and other comorbid diagnoses.

Hospital bloodborne pathogens programs: program characteristics and blood and body fluid exposure rates

OBJECTIVE

To describe hospital practices and policies relating to bloodborne pathogens and current rates of occupational exposure among healthcare workers.

PARTICIPANTS AND METHODS

Hospitals in Iowa and Virginia were surveyed in 1996 and 1997 about Standard Precautions training programs and compliance. The primary outcome measures were rates of percutaneous injuries and mucocutaneous exposures.

RESULTS

153 (64%) of 240 hospitals responded. New employee training was offered no more than twice per year by nearly one third. Most (79%-80%) facilities monitored compliance of nurses, housekeepers, and laboratory technicians; physicians rarely were trained or monitored. Implementation of needlestick prevention devices was the most common action taken to decrease sharps injuries. Over one half of hospitals used needleless intravenous systems; larger hospitals used these significantly more often. Protected devices for phlebotomy or intravenous placement were purchased by only one third. Most (89% of large and 80% of small) hospitals met the recommended infection control personnel-to-bed ratio of 1:250. Eleven percent did not have access to postexposure care during all working hours. Percutaneous injury surveillance relied on incident reports (99% of facilities) and employee health records (61%). The annual reported percutaneous injury incidence rate from 106 hospitals was 5.3 injuries per 100 personnel. Compared to single tertiary-referral institution rates determined more than 5 years previously, current injury rates remain elevated in community hospitals.

CONCLUSIONS

Healthcare institutions need to commit sufficient resources to Standard Precautions training and monitoring and to infection control programs to meet the needs of all workers, including physicians. Healthcare workers clearly remain at risk for injury. Further effective interventions are needed for employee training, improving adherence, and providing needlestick prevention devices.

Description of a new surveillance system for bloodstream and vascular access infections in outpatient hemodialysis centers

Bloodstream and vascular access infections are a threat to hemodialysis patients. However, there are few studies of rates of such infections and there are no standardized methods for ongoing data collection. Because of frequent hospitalizations and receipt of antimicrobials, hemodialysis patients are at high risk for infection with drug-resistant bacteria. This article describes a new voluntary national surveillance system. Each month participating dialysis center personnel will record the number of chronic hemodialysis patients that they treat (broken down into four types of vascular access). A one-page form will be completed for each hospitalization or in-unit IV antimicrobial start among these patients. These data will allow calculation, stratified by type of vascular access, of several rates, including hospitalizations, in-unit IV antimicrobial starts, and vascular access infections. For individual dialysis centers, this surveillance system will provide a simple and standardized method for recording data, calculating rates, and comparing rates over time. It is hoped that collection and examination of these data will lead to quality improvement measures. For government and the medical and public health communities, aggregation of these data from many dialysis centers will provide a wealth of information that is not currently available. For further information, or to receive a protocol for this study, contact Elaine R. Miller, RN, MPH, at (404)639-6422 (telephone), (404)639-6459 or 6458 (fax), or erm4@cdc.gov (e-mail:). Information is also available on the CDC website at http:@www.cdc.gov/ncidod/hip/Dialysis/dialysis.+ ++htm.

Standardized surveillance of hemodialysis vascular access infections: 18-month experience at an outpatient, multifacility hemodialysis center

OBJECTIVE

To develop a standardized surveillance system for monitoring hemodialysis vascular-access infections in order to compare infection rates between outpatient sites and to assess the effectiveness of infection control interventions.

DESIGN

Prospective descriptive analysis of incidence infection rates.

SETTING

An outpatient hemodialysis center with facilities in Idaho and Oregon.

PATIENTS

All outpatients receiving chronic outpatient hemodialysis.

RESULTS

There were 38,096 hemodialysis sessions (31,603 via permanent fistulae or grafts, 5,060 via permanent tunneled central catheters, and 1,433 via temporary catheters) during an 18-month study period in 1997 to 1998. We identified 176 total infections, for a rate of 4.62/1,000 dialysis sessions (ds). Of the 176, 80 involved permanent fistulae or grafts (2.53/1,000 ds), 69 involved permanent tunneled central catheter infections (13.64/1,000 ds), and 27 involved temporary catheter infections (18.84/1,000 ds). There were 35 blood-stream infections (0.92/1,000 ds) and 10 episodes of clinical sepsis (0.26 /1,000 ds). One hundred thirty-one vascular-site infections without bacteremia were identified (3.44/1,000 ds), including 65 permanent fistulae or graft infections (2.06/1,000 ds), 42 permanent tunneled central catheter infections (8.3/1,000 ds), and 24 temporary catheter infections (16.75/1,000 ds).

CONCLUSIONS

Infection rates were highest among temporary catheters and lowest among permanent native arteriovenous fistulae or synthetic grafts. This represents the first report of extensive incidence data on hemodialysis vascular access infections and represents a standardized surveillance and data-collection system that could be implemented in hemodialysis facilities to allow for reliable data comparison and benchmarking.

Infection control programs in long-term-care facilities: structure and process

Due to the rapid transfer of patients from the acute-care setting, the intensity of nursing care among residents in long-term-care facilities (LTCFs) has increased, transforming today's LTCFs into subacute healthcare facilities. Given the increased risk of infection among residents in LTCFs and the associated morbidity and mortality, evaluation of infection control programs in skilled nursing LTCFs is warranted. This article addresses the current structure and process of infection control programs in skilled nursing LTCFs.

A decade of prevalence surveys in a tertiary-care center: trends in nosocomial infection rates, device utilization, and patient acuity

OBJECTIVE

To evaluate the usefulness of repeated prevalence surveys to determine trends in the rates of nosocomial infections and to detect changes in risk factors (e.g., use of invasive devices) associated with nosocomial infections.

PATIENTS AND METHODS

Ten annual prevalence surveys were conducted by trained infection control practitioners between 1985 and 1995 for acute-care patients on the medical, surgical, pediatric, and obstetric-gynecologic services at a 900-bed, tertiary-care, teaching hospital with 750 acute-care beds. The same methods of chart review and concurrent reporting from nursing, the microbiology and clinical laboratory, and the pharmacy were used each year to collect data on the prevalence of nosocomial infections, invasive-device utilization, and abnormal laboratory indicators. Although data were collected on a single day, a period-prevalence study approach was used, because charts were reviewed for any infection data occurring within the 7 days prior to the survey.

RESULTS

The hospital census for acute care patients, as measured by the prevalence surveys, declined sharply over the 10 years, from 673 to 575 patients (P = .02). However, the medical service census increased from 150 to 188 patients (P = .01). During the same period, there was a significant decrease in the mean length of stay, from 7.3 to 6.0 days (P = .01), and a concomitant increase in the mean diagnosis related-group case-mix index, from 1.03 to 1.24 (P = .001). Overall, nosocomial infection rates remained unchanged over the study period (mean of 9.85 infections per 100 patients), but rates of nosocomial bloodstream infection increased from 0.0% in 1985 to 2.3% in 1995 (P = .05). Nosocomial infection rates were significantly higher on the medical and surgical services than on other services (P<.001). Utilization rates increased significantly for Foley catheters (9.0% to 16.0%, P = .002) and ventilators (5.0% to 8.0%, P = .05).

CONCLUSIONS

Despite apparent increases in the severity of illness of our patients, overall rates of nosocomial infection remained stable during a decade of study. Rates of nosocomial bloodstream infection increased, in parallel with National Nosocomial Infection Surveillance System data. We found repeated prevalence surveys to be useful in following trends and rates of infection, device utilization, and abnormal laboratory values among patients at our institution. Such methodologies can be valuable and low-cost components of a comprehensive infection surveillance, prevention, and control program and other potential quality-improvement initiatives, because they enable better annual planning of departmental strategies to meet hospital needs.

Regional data set of infection rates for long-term care facilities: description of a valuable benchmarking tool

BACKGROUND

Surveillance for nosocomial infections has been clearly established as a key element of all infection control programs. Surveillance programs in long-term care facilities (LTCFs) have been described, but published infection rates vary widely depending on the type of facility studied, nature of resident population, definitions used for LTCF-acquired infections, and type of data analysis. The aim of this initial study was to create a standardized regional data set of infection rates that could provide an external benchmark for interfacility comparison.

METHODS

The study included 6 LTCFs in close geographic proximity with similar patient populations. Surveillance in each facility was conducted by a licensed nurse supervised by an infectious diseases physician. Standard definitions for infections and uniform reporting forms were used. Data were pooled in an aggregate cumulative fashion, and data analysis was patterned after the National Nosocomial Infection Surveillance System.

RESULTS

The data set consisted of 328,065 resident-days of care during 30 months, with a total of 1252 infections for a pooled mean rate of 3.82 infections per 1000 resident-days of care. Infections for specific categories were 496 urinary tract infections (rate 1.51), 376 respiratory tract infections (rate 1.15), 88 gastroenteritis infections (rate 0.27), 283 skin and soft tissue infections (rate 0.86), 2 bloodstream infections (rate 0.06), and 3 unexplained febrile illnesses (rate 0. 09). Data analysis for comparison included interfacility means +/-2 standard deviations and percentiles of distribution.

CONCLUSIONS

A regional data set of infection rates for LTCFs allowed for meaningful interfacility comparison of overall and specific endemic rates and is a valuable benchmarking tool for participating facilities.

Comparison of inhibitory and bactericidal activities and postantibiotic effects of LY333328 and ampicillin used singly and in combination against vancomycin-resistant Enterococcus faecium

One hundred ninety-five individual vancomycin-resistant Enterococcus faecium (VRE) isolates from five upstate New York hospitals were studied for antimicrobial susceptibilities to LY333328, quinupristin-dalfopristin, teicoplanin, ampicillin, and gentamicin. LY333328 was the most active antibiotic against VRE. The effect of media and methods on the antibacterial activity of LY333328, its synergy with ampicillin, and the postantibiotic effects (PAE) of LY333328 and ampicillin were evaluated. In microdilution tests, the MIC of LY333328 at which 90% of the isolates were inhibited (MIC90) was 2 microg/ml in Mueller-Hinton II (MH II) broth and 1 microg/ml in brain heart infusion (BHI) broth. In contrast, on MH II agar the MIC90 was 4 microg/ml and on BHI agar it was >16 microg/ml. Bactericidal activity was observed for most strains at concentrations from 8 to >/=133 times the MIC of the tube macrodilution in MH II broth. A bactericidal effect of LY333328 plus ampicillin was demonstrated in time-kill studies, but there was great strain-to-strain variability. By the MH II agar dilution method, bacteristatic synergy (defined as a fractional inhibitory concentration of <0.5) with LY333328 and ampicillin was demonstrated for 61% of the strains tested. Under similar conditions, there was synergy with LY333328 and quinupristin-dalfopristin or gentamicin for 27 and 15% of the strains tested, respectively. The PAE of LY333328 was prolonged (23.0 h at 10 times the MIC). However, 50% normal pooled human serum decreased the PAE to 12.2 h at 10 times the MIC. Test conditions and media had a considerable effect on VRE susceptibilities to LY333328. The prolonged PAE of LY333328, a potent new bactericidal glycopeptide, and its synergy with ampicillin in a large proportion of strains suggest that further evaluation of this drug in pharmacokinetic studies and experimental infections, including those with VRE, is warranted.

Infection control concepts in critical care

Patients with critical illnesses requiring aggressive medical intervention are at risk of acquiring serious nosocomial infection that may lead to increases in medical expenditures, morbidity, and mortality. Infection control in this population entails continuous surveillance for hospital-acquired infection, with investigation of outbreaks. Policies for effective antibiotic utilization, disinfection of medical devices and hospital environment, and patient isolation may limit nosocomial infection in this population. Finally, an effective infection control program should protect the health care worker from hospital-acquired infections through educational programs, routine health surveillance, vaccinations, and post-exposure care.

Device-associated nosocomial infection surveillance in neonatal intensive care using specified criteria for neonates

Agreement on criteria for defining nosocomial infections is essential when surveillance is intended for quality assurance. The CDC criteria for patients < 12 months old were compared with locally developed criteria for neonates in a 10-month study of nosocomial infections in a Berlin University hospital. Six hundred and seventy-seven neonates were observed prospectively for 11,936 patient days. The overall nosocomial infection incidence rate was 13.2%. Because of the observed strength of agreement between the CDC and local criteria for central line-associated primary bloodstream infections and for ventilator-associated pneumonias (recommended by the NNIS system for inter-hospital comparisons) and the preference of the clinicians for the local criteria, we decided to use the latter for an ongoing surveillance system which nonetheless would retain the possibility for comparison with NNIS-data.

The global problem of antimicrobial resistance

Along with other multidrug-resistant pathogens previously identified, Streptococcus pneumoniae is becoming a serious concern in hospital and ambulatory care settings. The AIDS pandemic has increased the threat of resistance in Mycobacterium tuberculosis. Antimicrobial drug resistance involves three molecular mechanisms drug inactivation, altered cell permeability, and alteration of target sites. Surveillance and multidisciplinary approaches will be key to containing the threat of global antimicrobial resistance.

Postoperative infection in a double-occupancy operating room. A prospective study of two thousand four hundred and fifty-eight procedures on the extremities

The purposes of this study were to determine the rate of infection associated with elective outpatient operations on an extremity, performed in a double-occupancy operating room (one operating room designed to accommodate two separate operating teams), and to determine which factors influenced this rate. We evaluated the records of 2458 consecutive patients who had had such a procedure, performed by one of nine surgeons during a two and one-half-year period, and in whom the operative wound had been classified as clean (without a drain) or clean-contaminated (with a drain). The information regarding the factors associated with the operation and the operating-room environment was recorded for each patient at the time of the operation. Each wound was inspected periodically in the attending surgeon's office for at least thirty days postoperatively. Using definitions established by the Centers for Disease Control, the attending surgeon determined the presence of infection primarily by judging whether there was purulent drainage or whether erythema or swelling at the operative site was beyond that expected from the procedure. Of the 2458 patients, thirty-seven (1.5 per cent; 95 per cent confidence interval, 1.1 to 2.1 per cent) had infection of the operative wound. Only eight patients (0.3 per cent) had deep infection, with seven of the infections necessitating a reoperation. Infection developed in thirty of the 2311 clean wounds, a rate of 1.3 per cent (95 per cent confidence interval, 0.9 to 1.8 per cent), and in seven of the 147 clean-contaminated wounds, a rate of 4.8 per cent (95 per cent confidence interval, 2.3 to 9.5 per cent) (p = 0.001). No cross-contamination occurred between patients who had infection. The rate of infection was not related to the number of patients who were operated on in the same room at the same time. Logistic regression analysis, used to account for confounding factors, demonstrated a significant association between the classification of the wound (use of a drain) and a higher rate of infection (p = 0.006) as well as between the instillation of a topical steroid solution and a lower rate of infection (p = 0.04). It also demonstrated a significant difference, with respect to the rate of infection, among individual surgeons (p = 0.02).

Improving hospital-acquired infection rates: the CDC experience

BACKGROUND

The National Nosocomial Infections Surveillance (NNIS) System, begun in 1970 by the Centers for Disease Control to collect data on hospital-acquired infections, is one of the oldest continuously operating clinical performance indicator systems in the United States. Growth of the system, from 19 to 230 hospitals, has been accompanied by developments such as the evolution from hospitalwide to targeted surveillance, improved data processing and telecommunications for data collection and reporting, and risk adjustment.

ELEMENTS OF A SUCCESSFUL SYSTEM

The NNIS System provides specific, standardized methods for data collection and uses device-associated, device-day rates to risk adjust the data and make it meaningful for interhospital comparison. The system has been used as a tool for improving quality of care through prevention of nosocomial infections. For example, an 800-bed teaching hospital's rate of ventilator-associated nosocomial pneumonia in the surgical intensive care unit-49.5 infections per 1,000 ventilator days-was in excess of the 90th percentile. Improvements in care, including changing tubing and cascades every 48 hours and Ambu bags every 24 hours, as well as increased clinical evaluation of patients, was followed 12 months later by a decrease to 25.8 infections, well below the 90th percentile.

INFORMATION DISSEMINATION

Since 1992, staff from NNIS hospitals have met in a biennial conference to learn about advances in nosocomial infection surveillance and to share information with one another on infection control and quality improvement programs.

CONCLUSIONS

The NNIS experience can be used as a source of guidance for assessing the effectiveness and utility of other indicator systems.

Impact of changing pathogens and antimicrobial susceptibility patterns in the treatment of serious infections in hospitalized patients

The selection of drug-resistant pathogens in hospitalized patients with serious infections such as pneumonia, urinary tract infections (UTI), skin and skin-structure infections, and primary or secondary bacteremia has generally been ascribed to the widespread use of antimicrobial agents. Issues of concern regarding gram-negative bacilli include the expression of extended spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumonias and constitutive resistance in some Enterobacteriaceae caused by Bush group 1 beta-lactamases. Current concerns with gram-positive pathogens are increasing multidrug resistance in methicillin-resistant Staphylococcus aureus, enterococci, and coagulase-negative staphylococci, and increasing incidence of penicillin-resistant Streptococcus pneumoniae. Contemporary treatment strategies for pneumonia in hospitalized patients mandate early empiric therapy for the most likely gram-positive and gram-negative pathogens. Newer beta-lactams, such as fourth-generation cephalosporins, may be useful in the treatment of pneumonia, including those cases associated with bacteremia. Combination beta-lactam/beta-lactamase inhibitor drugs, an aminoglycoside co-drug, or a carbapenem may also be indicated. The initial treatment of UTI in the hospital setting also may be empirically treated with the newer cephalosporins, combination broad-spectrum penicillins plus an aminoglycoside, a quinolone, or a carbapenem. Current problems in treating UTI include the emergence of extended spectrum beta-lactamase-producing Escherichia coli, the tendency of fluoroquinolones both to select for resistant strains of major UTI pathogens and to induce cross-resistance among different drug classes, and beta-lactam and vancomycin resistance of enterococci and coagulase-negative staphylococci. Treatment of skin and skin-structure infections is complicated by the coexistence of gram-positive and gram-negative infections, which may be drug resistant. Both fourth-generation beta-lactams and carbapenems may have in vitro activity against these pathogens; however, where these drugs--with their increased spectra and lower affinity for beta-lactamases and less susceptibility to beta-lactamase hydrolysis--fit into the therapeutic armamentarium remains to be determined. Initial clinical studies appear to be promising, nonetheless. The ability of both nosocomial and community-acquired pathogens to develop resistance to powerful broad-spectrum agents presents a great challenge for prescribing patterns and in the development of new drugs to be relatively resistant to inactivation.

The scientific basis for using surveillance and risk factor data to reduce nosocomial infection rates

Research over the past 20 years has demonstrated that an active programme of surveillance with feedback of surgical wound infection rates to surgeons can reduce subsequent rates by 30-40%. For surveillance data and feedback to be meaningful and influential, however, certain rigorous methodological principles must be observed. First, surveillance data must be collected in an accurate, efficient and confidential manner. This requires written definitions of infection, regular clinical case-finding, post-discharge follow up for short-staying patients, and computer storage, analysis and reporting of the data in coded form that does not publicly identify individuals. Second, the variation in intrinsic risk of the patients of the various surgeons must be controlled for by stratifying the final infection rates on a multivariate risk index, which combines the traditional classes of wound contamination with measures of intrinsic patient susceptibility. This can be accomplished with a relatively small commitment of time by the Infection Control Nurse with the aid of sophisticated computer software that is now available.

Emerging infectious diseases in the United States, Improved surveillance, a requisite for prevention

Emerging infectious diseases such as prolonged diarrheal illness due to water-borne Cryptosporidium, hemorrhagic colitis and renal failure from food-borne E. coli O157:H7, and rodent-borne hantavirus pulmonary syndrome as well as reemerging infections such as tuberculosis, pertussis, and cholera vividly illustrate that we remain highly vulnerable to the microorganisms with which we share our environment. Prompt detection of new and resurgent infectious disease threats depends on careful monitoring by modern surveillance systems. This article focuses on five important elements of improved surveillance for emerging infections: 1) strengthening the national notifiable disease system, 2) establishing sentinel surveillance networks, 3) establishing population-based emerging infections programs, 4) developing a system for enhanced global surveillance, and 5) applying new tools and novel approaches to surveillance.

Genetic and molecular R-plasmid analysis of Enterobacteriaceae hospital strains at Children's Hospitals of the former USSR

R-plasmids from Enterobacteriaceae clinical strains, mainly Klebsiella and Serratia, isolated at different neonatal and children's hospitals of different cities of the former USSR for 10 years, were studied for their possible influence on the bacterial host phenotype. Hospital R-plasmids of stable inheritance persisted in hospitals from 2 to 7 years and were disseminated among strains of different genera (Klebsiella, Serratia, Enterobacter) and among different units. The data showed a possibility of long-term molecular rearrangements of R-plasmids in the hospital settings and an acquisition of genetic determinants encoding enterotoxin production. A novel R-plasmid encoding cytotoxicity to HEp-2 cells involved in two nosocomial outbreaks due to K. pneumoniae strains was reported. K. pneumoniae population heterogeneity was evaluated by using the plasmid parameters of strains. Their heterogeneity of a bacterial population was significantly lower during nosocomial outbreaks than in interepidemic periods.

Methicillin-resistant Staphylococcus aureus in U.S. hospitals, 1975-1991

OBJECTIVES

Analyze changes that have occurred among U.S. hospitals over a 17-year period, 1975 through 1991, in the percentage of Staphylococcus aureus resistant to beta-lactam antibiotics and associated with nosocomial infections.

DESIGN

Retrospective review. The percentage of methicillin-resistant S aureus (MRSA) was defined as the number of S aureus isolates resistant to either methicillin, oxacillin, or nafcillin divided by the total number of S aureus isolates for which methicillin, oxacillin, or nafcillin susceptibility test results were reported to the National Nosocomial Infections Surveillance (NNIS) System.

SETTING

NNIS System hospitals.

RESULTS

Of the 66,132 S aureus isolates that were tested for susceptibility to methicillin, oxacillin, or nafcillin during 1975 through 1991, 6,986 (11%) were resistant to methicillin, oxacillin, or nafcillin. The percentage MRSA among all hospitals rose from 2.4% in 1975 to 29% in 1991, but the rate of increase differed significantly among 3 bed-size categories: < 200 beds, 200 to 499 beds, and > or = 500 beds. In 1991, for hospitals with < 200 beds, 14.9% of S aureus isolates were MRSA; for hospitals with 200 to 499 beds, 20.3% were MRSA; and for hospitals with > or = 500 beds, 38.3% were MRSA. The percentage MRSA in each of the bed-size categories rose above 5% at different times: in 1983, for hospitals with > or = 500 beds; in 1985, for hospitals with 200 to 499 beds; and in 1987, for hospitals with < 200 beds.

CONCLUSIONS

This study suggests that hospitals of all sizes are facing the problem of MRSA, the problem appears to be increasing regardless of hospital size, and control measures advocated for MRSA appear to require re-evaluation. Further study of MRSA in hospitals would benefit our understanding of this costly pathogen.