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.     

Evaluation of postdischarge surveillance of surgical site infections after total hip and knee arthroplasty

BACKGROUND: Artificial joint replacement of hip (HPRO) and knee (KPRO) are 2 of about 20 categories of operative procedures of the surveillance of surgical site infection (SSI) as stated by nosocomial infections surveillance systems in the United States and in Germany. Periprosthetic SSI can manifest itself after a long period. METHODS: Seven hundred fifty-six orthopedic patients from 2 centers were evaluated after HPRO (n = 508) or KPRO (n = 248). SSI was recorded during hospitalization and for 12 month postdischarge. The surveillance regimen was extended by also sending patients a questionnaire after 12 months postdischarge. All complaints were followed up by contacting the patients and any clinicians and general practitioners (GPs) involved. Stratified infection rates and standardized infection ratio (SIR) were calculated and compared with reference data of the national surveillance system. RESULTS: The total response rate to the postal questionnaire survey was 85.2%. SSI was recorded in 16 patients (3.15%) after HPRO; 12 were detected by predischarge surveillance, and the 4 cases found postdischarge were all organ/space SSI. In total, only 1 SSI was detected after KPRO before discharge and none after discharge (SSI rate 0.40%). Time between discharge and detection of SSI cases ranged from 8 days to 8 months. SIR of HPRO was 1.25 and SIR of KPRO was 0.36. CONCLUSION: Because 25% of SSIs after HPRO occurred after discharge and all were organ/space SSI, highlights the importance of postdischarge surveillance of nosocomial infections (NIs). Because all SSIs were reported already by current surveillance, the extended postdischarge surveillance appears to be unnecessary. The pursuit of shorter hospital stay after surgery may challenge the methods of surveillance systems in future.     

Outcomes of a postdischarge surveillance system for surgical site infections at a Midwestern regional referral center hospital

BACKGROUND: Postdischarge surveillance has been reported in the literature as one method for detecting surgical site infections (SSIs) that more traditional methods of surveillance (review of readmission data, monitoring of microbiology, radiology, pharmacy antibiotic usage reports, and medical record review) fail to include. METHODS: This article describes a postdischarge surveillance program that used surgeon questionnaires and was implemented at a 225-bed Midwestern regional referral center hospital. Evaluation of the postdischarge program was accomplished by review of infection control program data for calendar years 1995 through 1997. RESULTS: Implementation of the postdischarge program resulted in an almost fourfold increase (in both 1995 and 1996) in SSI rates over the reported SSI rates if only traditional surveillance methods had been used. A majority of surgeons (79% in 1995 and 83% in 1996) had individual response rates of 80% or greater. In addition, implementation of the postdischarge program required only 3.5 to 4 additional hours per month. CONCLUSIONS: Results suggest that the postdischarge surveillance program identified SSIs missed by traditional surveillance methods, resulted in higher reported rates of SSI, was moderately to well accepted by surgeons, and was implemented with a minimum of organizational resources.     

Postdischarge surveillance of surgical site infections: a multi-method approach to data collection

BACKGROUND: Surveillance of surgical site infections (SSIs) is an important clinical indicator of quality patient care, yet an increasing number of SSIs manifest after discharge and are not detected through standard surveillance methods. AIM: This study evaluated a multimethod approach to postdischarge surveillance of SSIs with use of a cesarean section procedure as a case study. METHOD: A postdischarge questionnaire was sent on day 30 to women (n = 277) who had undergone cesarean section. A follow-up telephone interview was conducted if the questionnaire had not been returned within 2 weeks, a diagnosis of infection could not be clearly determined from the responses given, or to confirm the diagnosis of infection. If follow-up could not be made, a chart audit was undertaken. RESULTS: A total response rate of 89% (247/277) was obtained. Twenty-one women with SSI were identified through questionnaire responses. Additional strategies of telephone follow-up and chart review of patients with possible infection and of nonresponders identified more postdischarge infections (33%, 14/42). The overall infection rate was 17% (42/247) compared with 2.8% (7/247) at discharge. CONCLUSION: Postdischarge surveillance approaches need to achieve the best possible response rate, reflect follow-up health care delivery patterns, be cost-effective, gather data from both patients and treating physicians, and use standard definitions to facilitate benchmarking with other health care facilities and surveillance systems. The inclusion of contacting nonresponders in any method of postdischarge surveillance is recommended to determine the most accurate infection rate.     

Update on the Epidemiology and Prevention of Surgical Site Infections

Surgical site infections contribute significantly to the morbidity and mortality of the individual patient and impose a burden on the health care resources of the community. With the shift toward streamlined hospitalizations and ambulatory surgery, a majority of surgical site infections are being diagnosed after discharge. There are several tools available for identifying and risk stratifying patients that include the National Nosocomial Infections Surveillance system and the Study on the Efficacy of Nosocomial Infection Control index. If patients can be identified preoperatively, appropriate prophylactic measures and postdischarge surveillance can be undertaken, an underemphasized task faced by hospital systems today.     

Postdischarge surveillance for nosocomial wound infection: a brief review and commentary.

Escalating medical care costs during the last decade have resulted in shorter hospital stays and higher volumes of outpatients surgical procedures. As a result, the proportion of nosocomial surgical wound infections manifesting after discharge will increase. We performed a literature review to assess the current state of the art of postdischarge surveillance for nosocomial wound infection. From 20% to 70% of postoperative surgical site infections do not become apparent until after the patient's discharge, resulting in serious underreporting of true rates. Infections in outpatients are not being identified efficiently. Institutions using self-reporting methods report a low validity for these methods. The Centers for Disease Control and the Joint Commission for the Accreditation of Healthcare Organizations currently have no strong guidelines on the subject. Since valid postdischarge surveillance may become a necessity for a quality infection control program, new national recommendations are needed.     

Surgical site infections in cardiac surgery: an 11-year perspective

BACKGROUND: A surgical site infection (SSI) develops in 2% to 5% of patients undergoing operation. We report SSI surveillance at Baystate Medical Center, Springfield, Mass, in coronary artery bypass operation between 1991 and 2001, and demonstrate a substantial decline in SSI rates accomplished with use of multiple intervention strategies. METHODS: Infection documentation used Centers for Disease Control and Prevention (CDC) criteria and a postdischarge questionnaire. Infections were stratified by risk class. Strategies used to lower SSI rates included active surveillance and provision of authenticated SSI rate plus surgeon-specific rates. Interventions included outbreak analyses and targeted nasal mupirocin plus chlorhexidine showering. RESULTS: The rate of coronary artery bypass-related SSIs declined from >8% to <2%, comparing extremely favorably with CDC national data. Percentage of infections documented by postdischarge questionnaire was variable and did not change during the study period. Most SSIs were at the harvest site. Routine implementation of nasal mupirocin plus chlorhexidine preoperative showering effectively disrupted an outbreak of Staphylococcus aureus, and statistically decreased rates of postoperative infections with this organism. CONCLUSION: Regular provision of authenticated and verified data, use of postdischarge questionnaires, and careful attention to adverse trends and outbreaks with appropriate actions can substantially decrease rates of infections in coronary artery bypass operation.     

Validation of surgical site infection surveillance in orthopedic procedures

BACKGROUND: Valid data are essential for a national surveillance system of nosocomial infections. METHODS: In 8 hospitals conducting surgical site infection (SSI) surveillance for orthopedic procedures, a validation team performed a blinded retrospective chart review (10 operations with reported infections, 40 without) and interviewed infection control nurses. RESULTS: In total, 397 patient charts were reviewed. Positive and negative predictive values for routine surveillance were 94% (95% CI: 89%-99%) and 99% (95% CI: 99%-100%), respectively. When these results were applied to the aggregated surveillance data (403 infections, 10,068 noninfections), sensitivity was 75% (95% CI: 56%-93%) and specificity 100% (95% CI: 97%-100%). The following case finding methods were used: ward visits (in 7/8 hospitals), microbiology reports (5/8), ward notifications by link nurses (8/8), and other nursing (7/8) and medical (5/8) staff. The wound culture rate ranged from 9 to 67 per 1000 patient-days. All hospitals carried out postdischarge surveillance on readmission and all but 1 at follow-up visits and by an additional questionnaire. CONCLUSION: Most SSIs reported by the hospitals were true infections, showing that, when an SSI was reported, the definitions were correctly implemented. Some SSIs were missed, which might be due to weaknesses in case finding. Variation in diagnostic practices may also affect SSI rates.     

Effect of postdischarge surveillance on rates of infectious complications after cesarean section.

Decreases in length of stay for surgical procedures and increased outpatient surgery affect accuracy of surgical wound infection rates. To assess accuracy of rates for infectious complications after delivery by cesarean section, we implemented postdischarge surveillance at our hospital (4800 annual deliveries). Physician questionnaires were used. Response rate was greater than 90%. During the 5 months before postdischarge surveillance the overall infection rate was 1.6%; afterward the rate increased to 6.3% (p = 0.0003). Approximately 59% of infectious complications would have gone undetected with only inpatient surveillance. We conclude that postdischarge surveillance is necessary for an accurate determination of rates of infectious complications. The need among this population reflects relatively short postpartum hospitalization and emphasis on outpatient management of postoperative complications.     

Electronic chart review as an aid to postdischarge surgical site surveillance: increased case finding

BACKGROUND: At the University of Michigan Hospitals and Health Centers, there is increasing use of an electronic medical record. Because orthopedic surgeons dictate all outpatient visits to the patient's electronic record, total knee arthroplasties were chosen to determine whether the use of electronic medical records increased case finding. METHODS: All patients who underwent a total knee arthroplasty during the study period (1996-1999) were followed prospectively with the use of the National Nosocomial Infection Surveillance System definitions. Traditional surveillance methods were used to ascertain infections. In addition, each patient's postdischarge outpatient clinic chart was reviewed electronically for 1 year after operation. RESULTS: From 1996 to 1999, 555 procedures were performed. Overall, 25 infections were identified after operation. Seven infections were identified through traditional surveillance methods, which resulted in an average surgical site infection rate of 1.3%. The use of electronic chart review surveillance after discharge revealed a rate of 4.5%, which was significantly higher than traditional surveillance (P <.01). Eighteen of 25 infections (72%) would not have been identified with the use of traditional surveillance methods. CONCLUSION: Postdischarge electronic chart review enhanced case finding significantly, which resulted in a more accurate infection rate. Awareness should be given to the institutions' surveillance methods and intensity when comparing to published rates.     

When continuous surgical site infection surveillance is interrupted: the Royal Hobart Hospital experience

BACKGROUND: The prevalence of surgical site infections (SSI) is second only to urinary tract infections in hospitalized patients. They continue to threaten the health of hospitalized patients and impact negatively on the financial solvency of hospitals through prolonged hospitalization, increased rates of rehospitalization, and significantly increased health care costs. METHODS: We describe the effect of a 12-year surveillance program that included postdischarge follow-up and feedback to clinicians on the rate of SSI and the effect when surveillance is interrupted. Surgical procedures performed at the Royal Hobart Hospital (RHH), a university teaching hospital in Australia, between 1988 and 2001 were monitored for evidence of SSI in hospitals and for up to 30 days postoperatively. The surveillance program was inadvertently disrupted for 15 months from October 1990 to January 1992 and then recommenced. It has been ongoing since that time, apart from a 3-month interruption in 1998. Infection rates were determined on a regular basis, and these results were provided to surgeons, theatre staff, and surgical ward staff every 6 months. Patients included all adult surgical patients with an incisional wound, excluding burn patients and day-only surgical patients. RESULTS: Over the 12-year active surveillance period, 47,581 surgical procedures were followed for SSI. In-hospital SSI rates declined significantly over the study period from 4.7% (95% CI: 3.9%-5.6%) in 1988-1989 to 1.2% (95% CI: 0.8%-1.7%) in 2001 (P < .0001). Infection rates fell rapidly following the commencement of the program. This decline was halted during the period from October 1990 to January 1992 when the program was suspended. In-hospital SSI rates declined once again following the recommencement of the surveillance program, and these lower rates have been maintained. In contrast, postdischarge infection rates rose significantly from 1.2% (95% CI: 0.8%-1.7%) in 1988-1989 to 2.1% (95% CI: 1.6%-2.7%) in 2001 (P < .0001). CONCLUSION: The introduction of a program of continuous SSI surveillance at the RHH was associated with a reduction in the in-hospital and total SSI rate. This phenomenon was repeated following the recommencement of the program after a temporary interruption. Increasing numbers of SSIs are arising after hospital discharge. Many of these patients are readmitted to the hospital for further management of the SSI. Surveillance programs that do not perform postdischarge surveillance will have difficulty in capturing this data. Our experience supports the Study on the Efficacy of Nosocomial Infection Control (SENIC) findings, showing that health care facilities can achieve improved levels of infection management with active surveillance programs.     

Surgical wound infections documented after hospital discharge

Shorter lengths of hospitalization may result in more surgical wound infections being documented after hospital discharge. The current investigation analyzed 1644 surgical procedures performed over a 3-month period, and documented surgical wound infections both before and for 1 month after hospital discharge. Physician and patient questionnaires were used. One hundred eight infections were noted, of which 50 (46%) were seen after hospital discharge by either the patient or the surgeon. Rates of infection were 5.2%, 7.5%, and 7.5% for clean, clean-contaminated, and contaminated-dirty categories, respectively. Had postdischarge surveillance not been used, rates would have appeared to be 2.5%, 6.5%, and 6.8% for the same surgical classes. Infections following clean and clean-contaminated procedures were more likely to be noticed after hospital discharge. Excluding those that were patient-documented, wound infection rates would have been 4.2% (clean), 6.3% (clean-contaminated) and 6.8% (contaminated-dirty). Postdischarge surveillance is imperative to meaningfully document true rates of surgical wound infection, inasmuch as increasing numbers are likely to occur only after patients leave the hospital.     

Postdischarge surveillance: the impact on surgical site infection incidence in a Brazilian university hospital

OBJECTIVE: This prospective cohort study was carried out in a surgical unit of a university hospital in Brazil. The purpose of the study was to determine the incidence of surgical site infection (SSI) in patients during hospitalization and after discharge from the hospital. METHOD: In a sample of 630 patients who underwent surgical procedures, association among diagnosis of SSI (in-hospital or postdischarge), class of the surgery (elective or emergency), hospitalization period, patient's clinical condition (American Society of Anesthesiologists [ASA] score), classification of surgical site, and duration of surgical procedure were verified. RESULTS: Fifty SSIs were diagnosed while the patients were still in the hospital, and 140 postdischarge. Hospitalization periods >5 days and worse clinical condition (ASA III) were associated with a higher SSI incidence. Classification of SSI was not correlated to the incidence of in-hospital SSI, except for clean surgeries. Surgical procedures of >5 hours duration were correlated to SSI during hospitalization, and procedures of >2 hours duration correlated to a postdischarge SSI. Most SSIs (73.7%) were diagnosed postdischarge. CONCLUSION: Results show a high incidence of postsurgical infection detected during postdischarge surveillance, which suggests the need for postdischarge follow-ups for surgical patients.     

A review of human salmonellosis: III. Magnitude of Salmonella infection in the United States

National surveillance for salmonella infections was established in 1962, following recognition of the importance of Salmonella organisms as the cause of potentially preventable infectious disease in the United States. Reports of infections due to Salmonella have risen progressively to approximately 40,000 per year. In contrast, the parallel reporting system for infections due to Shigella shows no such increase. Because a passive surveillance system is used, it has been assumed salmonella infections have been substantially underreported. Three independent methods-determination of carriage rates, calculation of sequential surveillance artifacts, and calculation of overall surveillance artifact-were used to estimate the annual number of salmonella infections in the United States; the results were compared with those of a previous study. These methods produced estimates ranging from 800,000 to 3,700,000 (mean = 1,900,000; median = 1,400,000) infections annually. Accurate assessment of the number of infections is important for determining complication rates and for evaluating the efficacy of control programs.     

Surgical wound infections diagnosed after discharge from hospital: epidemiologic differences with in-hospital infections

Bacground: The purpose of this study was to study postoperative infections detected in hospital and after discharge and to identify risk factors for such infections.Methods: A prospective cohort study was used, with a follow-up of 30 days after hospital discharge, on 1483 patients admitted to the general surgery service of a tertiary care hospital. The main outcome measure was surgical wound infection (SWI). Relative risks, crude and multiple risk factors adjusted for by logistic regression analysis, and their 95% confidence intervals (CIs) were estimated.Results: During follow-up 155 patients showed evidence of nosocomial infection, 134 in hospital and 21 at home, yielding a cumulative incidence of 10.5%. According to several variables (age, American Society of Anesthesiologists score, serum albumin, the SENIC and National Nosocomial Infections Surveillance indexes of intrinsic patient risk, length of hospital stay, etc.) there were no differences between patients with postdischarge SWI and uninfected patients; however, differences were detected between postdischarge SWI and in-hospital SWI, as well as between patients with in-hospital SWI and patients without infections. The analysis of risk factors showed that most predictors for in-hospital SWI did not behave in the same manner for postdischarge SWI. Stepwise logistic regression analysis identified cancer (odds ratio = 4.5, 95% CI = 1.7 to 12.2, p = 0.003) and surgeon performing the operation (for medium risk OR = 4.4, 95% CI = 0.9 to 21.3, p = 0.059; for high risk, OR = 3.0, 95% CI = 0.7–13.3, p = 0.144) as independent risk factors for postdischarge SWI.Conclusions: There were important epidemiologic differences between in-hospital SWI and postdischarge SWI; most risk factors for in-hospital SWI are not predictors for postdischarge SWI.     

Surgeons' perspectives on surgical wound infection rate data in Queensland, Australia

BACKGROUND: The results of the Study on the Efficacy of Nosocomial Infection Control (SENIC) project demonstrated that hospitals with active infection control programs had lower rates of nosocomial infection than those without such programs. A key component of these programs was the inclusion of a systematic method for monitoring nosocomial infection and reporting these infections to clinicians. OBJECTIVES: To identify the perspectives of surgeons in Queensland, Australia, regarding infection rate data in terms of its accuracy and usefulness as well as their perceptions regarding acceptable infection rates for surgical procedures classified as "clean" or "contaminated." METHODS: A postal survey was conducted, with a convenience sample of 510 surgeons. RESULTS: More than 40% (n = 88) of respondents believed that the acceptable infection rate associated with clean surgical procedures should be less than 1%, a rate much lower than the threshold of 1.4% to 4.1% set by the Australian Council on Healthcare Standards (ACHS). Almost 30% (n = 55) of respondents reported that they would accept infection rates of 10% or higher for contaminated surgical procedures, which is higher than the ACHS threshold of 1.4% to 7.9%. Respondents identified failure to include postdischarge infections in the data and difficulties standardizing criteria for diagnosis of infection as the major impediments to the accuracy and usefulness of data provided. CONCLUSION: The results of this study have significant implications in relation to the preparation of surgical site infection reports, especially in relation to the inclusion of postdischarge surveillance data and information regarding pathogens, antibiotic sensitivities, and comorbidities of patients developing surgical site infection. Surgeons also identified the need to include information regarding the use of standardized definitions in the diagnosis of wound infection and parameters that allow comparison of infection rates to improve their perceptions regarding data accuracy and usefulness.     

Surgical site infections in Italian Hospitals: a prospective multicenter study

Background  

Surgical site infections (SSI) remain a major clinical problem in terms of morbidity, mortality, and hospital costs. Nearly 60% of SSI diagnosis occur in the postdischarge period. However, literature provides little information on risk factors associated to in-hospital and postdischarge SSI occurrence. A national prospective multicenter study was conducted with the aim of assessing the incidence of both in-hospital and postdisharge SSI, and the associated risk factors.     

Benchmarking for prevention: the Centers for Disease Control and Prevention's National Nosocomial Infections Surveillance (NNIS) system experience

Healthcare-associated infections are a major cause of morbidity and mortality at hospitals in the United States. Surveillance of these infections identifies secular trends and provides data upon which prevention interventions can be based in order to improve patient safety. National surveillance of healthcare-associated infections was initiated in the United States in 1970. Since that time, the Centers for Disease Control and Prevention's (CDC) National Nosocomial Infections Surveillance (NNIS) system has provided standardized methods for collecting and comparing healthcare-associated infection rates and the national benchmark infection rate data for inter- and intra-hospital comparisons. The surveillance methods used and results of the implementation of these methods are reviewed. The number of hospitals participating in the CDC's national surveillance of healthcare-associated infections has grown from approximately ten to 20 hospitals in 1970 to over 300 hospitals in 2002. Over the years, NNIS system participants have used standardized definitions, standardized surveillance component protocols, risk stratification for calculation of infection rates and provided national benchmark infection rates for inter- and intra-hospital comparisons. These methods have resulted in a significant reduction in bloodstream infections, urinary tract infections and pneumonia in intensive care unit (ICU) patients and surgical site infections in surgical patients. The NNIS data show that national surveillance of healthcare-associated infections combined with an intervention prevention program can reduce infection rates, reduce morbidity and mortality and improve patient safety. Establishment of such healthcare-associated infection surveillance and prevention systems in countries throughout the world should be a priority.     

Determinants of surgical site infection after breast biopsy

BACKGROUND: Surgical site infections (SSI) following clean and clean-contaminated ambulatory surgery at Bon Secours Cottage Health Services are monitored utilizing a postdischarge surveillance form in addition to traditional surveillance. From January 2000 to December 2002, the clean procedure SSI rate was 0.73% (31/4266) versus 1.58% (15/950) for breast biopsy, P = .04. A case-control study was performed to identify risk factors for infection. METHODS: A case patient was identified as any patient having an ambulatory breast biopsy from January 2000 to December 2002 with SSI identified by the Centers for Disease Control and Prevention (CDC) definition of nosocomial infection. For each case patient, 3 randomly selected control patients were matched by date and procedure. RESULTS: Factors significantly associated with the development of SSI were duration of surgery (case mean, 71.7 minutes vs control mean, 34.7 minutes, P < .01) and presence of surgical drains (26.7% of cases vs 6.7% of controls, P = .04). Factors determined not to be associated with SSI were obesity (P = .88) and preoperative needle localization (P = .88). CONCLUSIONS: We conclude that there is a significant difference between the breast biopsy infection rate and the clean procedure infection rate in ambulatory surgery. Duration of surgery and presence of surgical drains were associated with increased infection rate.     

Surveillance of human Campylobacter infections in France--part 1--which data? A study of microbiological laboratories, 2000

The frequency of Campylobacter infections in humans, their potential severity, and the existence of preventive measures justify the implementation of a surveillance system for these infections. Before the implementation of the surveillance system, a survey of the Campylobacter diagnostic practices in the laboratories was performed. In the laboratories that responded, most investigated for Campylobacter at least once in 1999. Identification of the Campylobacter species was carried out by 86% of hospital laboratories and 37% of private laboratories. Antibiotic sensitivity tests were carried out by 75% and 32% of them respectively. Many laboratories test for Campylobacter in stool samples using comparable methods showing the feasibility of a surveillance system.