We evaluated 4 important outcomes associated with postoperative nosocomial infection: costs, mortality, excess length of stay, and utilization of healthcare resources.

The outcomes for patients who underwent general, cardiothoracic, and neurosurgical operations were recorded during a previous clinical trial. Multivariable analyses including significant covariates were conducted to determine whether nosocomial infection significantly affected the outcomes.

A large tertiary care medical center and an affiliated Veterans Affairs Medical Center.

A total of 3,864 surgical patients.

The overall nosocomial infection rate was 11.3%. Important covariates included age, Karnofsky score, McCabe and Jackson classification of the severity of underlying disease, National Nosocomial Infection Surveillance system risk index, and number of comorbidities. After accounting for covariates, nosocomial infection was associated with increased postoperative length of stay, increased costs, increased hospital readmission rate, and increased use of antimicrobial agents in the outpatient setting. Nosocomial infection was not associated independently with a significantly increased risk of death in this surgical population.

Postoperative nosocomial infection was associated with increased costs of care and with increased utilization of medical resources. To accurately assess the effects of nosocomial infections, one must take into account important covariates. Surgeons seeking to decrease the cost of care and resource utilization must identify ways to decrease the rate of postoperative nosocomial infection.

We estimated the impact of hip replacement-associated surgical site infection (SSI) on morbidity and length of stay.

This was a pairwise matched (1 : 1) case-control study nested in a cohort. All patients who underwent hip replacement from January 1, 2000, to June 30, 2004, were prospectively enrolled for the nested case-control design analysis and were monitored from the time of surgery until hospital discharge, including any patients readmitted because of infection.

Among the 1,260 hip replacements performed, 28 SSIs were detected, yielding a crude SSI rate of 2.2%. The median excess length of stay attributable to SSI was 32.5 days (P< .001), whereas the median prolonged postoperative stay due to SSI was 31 days (P< .001). Deep-wound SSI was the type that prolonged hospital stay the most (up to 49 days). Of the patients who developed an SSI, 4 required revision surgery, for an SSI-related morbidity rate of 14.3%.

SSI prolongs hospital stay; however, although hospital stay is a rough indicator of the cost of this complication, to accurately estimate the costs of SSI, we would need to consider individual costs in a linear regression model adjusted for all possible confounding factors.

Staphylococcus aureus is the most common cause of healthcare-associated infections. Intranasal mupirocin treatment probably decreases S. aureus infections among colonized surgical patients. Using cost-effectiveness analysis, we evaluated the cost-effectiveness of preoperative use of mupirocin for the prevention of healthcare-associated S. aureus infections.

Three strategies were compared: (1) screen with nasal culture and give treatment to carriers, (2) give treatment to all patients without screening, and (3) neither screen nor treat. A societal perspective was taken. Adverse outcomes included bloodstream infection, pneumonia, surgical site infection, death due to underlying illness or infection, readmission, and the need for home health care. Data inputs were obtained from an extensive MEDLINE review and from publicly available government data sources. The following base-case data inputs (and ranges) for sensitivity analysis were used: rate of S. aureus carriage, 23.1% (19%-55%); efficacy ofmupirocin treatment, 51% (8%-75%); mupirocin treatment cost, $48.36 ($24.18-$57.74); and hospital costs of bloodstream infection, $25,128 ($6,194-$40,211), pneumonia, $18,366 ($5,574-$28,952), and surgical site infection $16,256 ($5,119-$22,553). Widespread use ofmupirocin has been associated with high levels of mupirocin resistance; therefore, a broad range of estimates for efficacy was tested in the sensitivity analysis.

The target population included patients undergoing nonemergent surgery requiring postoperative hospitalization.

Both the screen-and-treat and treat-all strategies were cost saving, saving $102 per patient screened and $88 per patient treated, respectively. In 1-way sensitivity analyses, the model was robust with respect to all data inputs except for the efficacy ofmupirocin treatment. If the efficacy is less than 16.1%, then the screen-and-treat strategy is cost incurring. A treat-all strategy was more cost saving if the rate of S. aureus carriage was greater than 42.7%, the mupirocin cost was less than $29.87, or nursing compensation was greater than $64.21 per hour.

Administration of mupirocin before surgery is cost saving, primarily because healthcare-associated infections are very expensive. The level of mupirocin efficacy is critical to the cost-effectiveness of this intervention.

To estimate the rate of surgical site infection (SSI) occurring after hospital discharge, to evaluate whether limiting surveillance to inpatients underestimates the true rate of SSI, and to select surgical procedures that should be included in a postdischarge surveillance program.

Prospective surveillance study.

A surgical ward at a university teaching hospital in Italy.

A total of 264 surgical patients were included in the study.

The global SSI rate was 10.6% (28 patients); 17 (60.2%) of patients with an SSI developed the infection after hospital discharge. The overall mean length of postoperative stay (±SD) for patients who acquired a postdischarge SSI was 4.9 ± 3.7 days, and SSI was diagnosed a mean duration (±SD) of 11.5 ± 4.5 days after surgery. Among procedures with postdischarge SSIs, those classified by the National Nosocomial Infections Surveillance system (NNIS) as herniorrhaphy, mastectomy, other endocrine system, and other integumentary system were associated with a mean postoperative stay that was less than the mean time between the operation and the onset of SSI. Four (36%) of in-hospital SSIs occurred after procedures with an NNIS risk index of 0, and 7 (64%) occurred after procedures with an NNIS risk index of 1 or higher. Of the 17 SSIs diagnosed after discharge, 14 procedures (82%) had an NNIS risk index of 0, compared with 3 procedures (18%) with an NNIS risk index of 1 or higher.

Our results revealed an increased risk of postdischarge SSI after some types of surgical procedures and suggest that there is an important need to change from generalized to NNIS operative category-directed postdischarge surveillance, at least for procedures locally considered to be high-risk.

To investigate the impact of postdischarge surveillance (PDS) on surgical-site infection (SSI) rates for selected surgical procedures in acute care hospitals in Scotland.

Prospective surveillance of SSI after selected surgical procedures.

The Scottish Surveillance of Healthcare Associated Infection Programme (SSHAIP), which is based on the methodology of the Centers for Disease Control and Prevention (CDC) National Nosocomial Infections Surveillance system (NNIS). Thirty-two of 46 acute care hospitals throughout Scotland contributed data to SSHAIP for this study.

Data were from 21,710 operations that took place between April 1, 2002, and June 30, 2004; nine categories of surgical procedures were analyzed. CDC NNIS system definitions and methods were used for SSI PDS. PDS is a voluntary component of the mandatory SSI surveillance program in Scotland. PDS was categorized as none, passive, active without direct observation, and active with direct observation.

From our study information, PDS data were available for 12,885 operations (59%). A total of 2,793 procedures (13%) were associated with passive PDS and 10,092 (46%) with active PDS. The SSI rate among the 8,825 operations with no PDS was 2.61% (95% confidence interval [CI], 2.3%-3.0%), which was significantly lower than the SSI rate found among the 12,885 operations for which PDS was performed (6.34% [95% CI, 5.9%-6.8%]). For breast surgery, cesarean section, hip replacement, and abdominal hysterectomy, the rate of SSI when PDS was performed was significantly higher than that when PDS was not performed (P< .01 for each procedure). No differences in SSI rates were found for surgery to repair fractured neck of the femur or for knee replacement. SSI rates were examined according to procedure type, performance of PDS, and NNIS risk index; rates of SSI increased with NNIS risk index within procedure group and PDS group. Logistic regression analyses confirmed that procedure type, performance of PDS, and NNIS risk index were all statistically independent predictors of report of an SSI (P< .05).

This Scottish national data set incorporates a substantial amount of PDS data. We recommend a procedure-specific approach to PDS, with direct observation of patients after breast surgery, cesarean section, and hysterectomy, for which the length of stay is typically short. Readmission surveillance may be adequate to detect most SSIs after orthopedic surgery or vascular surgery, for which the length of stay is typically longer.

To evaluate the impact of postdischarge surveillance on surgical site infection (SSI) rates after orthopedic surgery.

Nine hospitals participating in the Finnish Hospital Infection Program.

All patients who underwent hip or knee arthroplasty or open reduction of a femur fracture during 1999-2002.

The date of discharge was available for 11,812 procedures (90%). The median length of hospital stay was 8 days (range per hospital, 6-9 days). The overall SSI rate was 3.3% (range, 0.8%-6.4%). Of 384 SSIs detected, 216 (56%; range, 28%-90%) were detected after discharge: 93 (43%) were detected on readmission to the hospital, 73 (34%) at completion of a postdischarge questionnaire, and 23 (11%) at a follow-up visit. For 27 postdischarge SSIs (13%), the location of detection was unknown. Altogether, 32 (86%) of 37 of organ/space SSIs, 57 (80%) of 71 deep incisional SSIs, and 127 (46%) of 276 superficial incisional SSIs were detected after discharge. Most SSIs (70%) detected on readmission were severe (organ/space or deep incisional), whereas most SSIs (86%) detected at follow-up visits or at completion of a postdischarge questionnaire were superficial. Of all SSIs, 78% (range, 48%-100%) were microbiologically confirmed. Microbiologic confirmation was less common after discharge than during postoperative hospital stay (66% vs 93%; P< .001).

Postdischarge surveillance had a large impact on the rate of SSI detected after orthopedic surgery. However, postdischarge surveillance conducted by means of a questionnaire detected only a minority of deep incisional and organ/space SSIs.

To develop prognostic models for improved risk adjustment in surgical site infection surveillance for 5 surgical procedures and to compare these models with the National Nosocomial Infection Surveillance system (NNIS) risk index.

In a multicenter cohort study, prospective assessment of surgical site infection and risk factors was performed from 1996 to 2000. In addition, risk factors abstracted from patient files, available in a national medical register, were used. The c-index was used to measure the ability of procedure-specific logistic regression models to predict surgical site infection and to compare these models with models based on the NNIS risk index. A c-index of 0.5 indicates no predictive power, and 1.0 indicates perfect predictive power.

Sixty-two acute care hospitals in the Dutch national surveillance network for nosocomial infections.

Patients who underwent 1 of 5 procedures for which the predictive ability of the NNIS risk index was moderate: reconstruction of the aorta (n = 875), femoropopliteal or femorotibial bypass (n = 641), colectomy (n = 1,142), primarytotal hip prosthesis (n = 13,770), and cesarean section (n = 2,962).

The predictive power of the new model versus the NNIS index was 0.75 versus 0.62 for reconstruction of the aorta (P< .01), 0.78 versus 0.58 for femoropopliteal or femorotibial bypass (P< .001), 0.69 versus 0.62 for colectomy (P< .001), 0.64 versus 0.56 for primary total hip prosthesis arthroplasty (P< .001), and 0.70 versus 0.54 for cesarean section (P< .001).

Data available from hospital information systems can be used to develop models that are better at predicting the risk of surgical site infection than the NNIS risk index. Additional data collection may be indicated for certain procedures–for example, total hip prosthesis arthroplasty.

To compare the rate of surgical site infection (SSI) before and after an intervention period in which an optimized policy for antibiotic prophylaxis was implemented. To demonstrate that a more prudent, restrictive policy would not have a detrimental effect on patient outcomes.

Before-after trial with prospective SSI surveillance in the Dutch nosocomial surveillance network (Preventie Ziekenhuisinfecties door Surveillance [PREZIES]), using the criteria of the Centers for Disease Control, including postdischarge surveillance for up to 1 year.

During a preintervention period and a postintervention period (both 6-13 months), 12 Dutch hospitals collected data on antimicrobial prophylaxis and SSI rates. The study was limited to commonly performed surgical procedures in 4 specialties: vascular, intestinal, gynecological and orthopedic surgery. Selected risk factors for analysis were sex, age, American Society of Anesthesiologists classification, wound contamination class, duration of surgery, length of hospital stay before surgery, and urgency of surgery (elective or acute).

A total of 3,621 procedures were included in the study, of which 1,668 were performed before the intervention and 1,953 after. The overall SSI rate decreased from 5.4% to 4.5% (P = .22). Among the procedures included in the study, the largest proportion (55%) were total hip arthroplasty, and the smallest proportion (2%) were replacement of the head of the femur. SSI rates varied from 0% for vaginal hysterectomy to 21.1% for femoropopliteal or femorotibial bypass surgery. Crude and adjusted odds ratios showed that there were no significant changes in procedure-specific SSI rates after the intervention (P>.1).

An optimized and restrictive antibiotic prophylaxis policy had no detrimental effect on the outcome of clean and clean contaminated surgery, as measured by SSI rate.

To evaluate whether surgical site infection (SSI) rates decrease in surgical departments as a result of performing active SSI surveillance.

Retrospective multiple logistic regression analyses.

A group of 130 surgical departments of German hospitals participating in the Krankenhaus Infektions Surveillance System (KISS).

Data for 19 categories of operative procedures performed between January 1997 and June 2004 were included (119,114 operations). Active SSI surveillance was performed according to National Nosocomial Infections Surveillance system (NNIS) methods and definitions. Departments' SSI rates were calculated individually for each year of surveillance and for each operative procedure category, taking into account when the individual departments had begun their surveillance activities. Multiple logistic regression analyses on a single operation basis were carried out with stepwise variable selection to predict outcomes for patients with SSI. The variables included were as follows: the department's year of participation, NNIS risk index variables, patients' age and sex, and the hospitals' structural characteristics, such as yearly operation frequency, number of beds, and academic status.

For 14 of 19 operative procedure categories analyzed, there was a tendency toward lower SSI rates that was associated with increasing duration of SSI surveillance. In multiple logistic regression analyses of pooled data for all operative procedures, the departments' participation in the surveillance system was a significant independent protective factor. Compared with the surveillance year 1, the SSI risk decreased in year 2 (odds ratio, 0.84; 95% confidence interval, 0.77-0.93) and in year 3 (odds ratio, 0.75; 95% confidence interval, 0.68-0.82), and there was no change in year 4.

The SSI incidence was reduced by one quarter as a result of the surveillance-induced infection control efforts, which indicates the usefulness of a voluntary surveillance system.

To investigate a case of Creutzfeldt-Jakob disease (CJD) possibly acquired from contaminated neurosurgical instruments.

Retrospective review of medical records, hospital databases, service log books, and state vital statistics.

A tertiary care hospital (hospital A) in Missouri.

The case patient was a 38-year-old African American woman with a 9-month history of progressive memory loss, visual disturbances, and dementia. She underwent neurosurgery in November 1996. CJD was confirmed in April 2004 by immunodiagnostic testing of brain biopsy samples. All patients who underwent neurosurgery at the same hospital within 6 months before or after the case patient's procedure were identified and investigated for preoperative or postoperative evidence of CJD.

We reviewed data on 268 neurosurgical procedures, 84 pathology log entries, and 60 death certificates for neurosurgical patients at hospital A and identified 2 suspected cases of CJD. Clinical features and definitive prion testing of stored brain biopsy samples excluded a diagnosis of CJD. Standard operating room procedures were in place, but specific protocols for handling instruments potentially contaminated with prions were not used.

Neurosurgical instruments were not implicated as the source exposure for CJD in the case patient. The 2 patients with suspected CJD were identified from different data sources, suggesting good internal consistency in data collection. The key elements of this investigation are suggested for use in future investigations into potential cases of iatrogenic CJD.

To evaluate the effectiveness of an intervention based on training and the use of a protocol with an automatic stop of antimicrobial prophylaxis to improve hospital compliance with surgical antibiotic prophylaxis guidelines.

An interventional study with a before-after trial was conducted in 3 stages: a 3-year initial stage (January 1999 to December 2001), during which a descriptive-prospective survey was performed to evaluate surgical antimicrobial prophylaxis and surgical site infections; a 6-month second stage (January to June 2002), during which an educational intervention was performed regarding the routine use of a surgical antimicrobial prophylaxis request form that included an automatic stop of prophylaxis (the “automatic-stop prophylaxis form”); and a 3-year final stage (July 2002 to June 2005), during which a descriptive-prospective survey of surgical antimicrobial prophylaxis and surgical site infections was again performed.

An 88-bed teaching hospital in Entre Ríos, Argentina.

A total of 3,496 patients who underwent surgery were included in the first stage of the study and 3,982 were included in the final stage.

Comparison of the first stage of the study with the final stage revealed that antimicrobial prophylaxis was given at the appropriate time to 55% and 88% of patients, respectively (relative risk [RR], 0.27 [95% confidence interval {CI}, 0.25-0.30]; P < .01); the antimicrobial regimen was adequate in 74% and 87% of patients, respectively (RR, 0.50 [95% CI, 0.45-0.55]; P < .01); duration of the prophylaxis was adequate in 44% and 55% of patients, respectively (RR, 0.80 [95% CI, 0.77-0.84]; P < .01); and the surgical site infection rates were 3.2% and 1.9%, respectively (RR, 0.59 [95% CI, 0.44-0.79]; P < .01). Antimicrobial expenditure was US$10,678.66 per 1,000 patient-days during the first stage and US$7,686.05 per 1,000 patient-days during the final stage (RR, 0.87 [95% CI, 0.86-0.89]; P<.01).

The intervention based on training and application of a protocol with an automatic stop of prophylaxis favored compliance with the hospital's current surgical antibiotic prophylaxis guidelines before the intervention, achieving significant reductions of surgical site infection rates and substantial savings for the healthcare system.

To assess the impact of antibiotic prophylaxis on the emergence of vancomycin-resistant strains of Enterococcus faecium, Enterococcus faecalis, and Staphylococcus aureus and the incidence of surgical site infection (SSI) after vancomycin or cefazolin prophylaxis for femoral neck fracture surgery.

Prospective cohort study.

A hospital with a high prevalence of methicillin-resistant S. aureus (MRSA) carriage.

All patients admitted with a femoral neck fracture from March 1, 2004 through February 28, 2005 were prospectively identified and screened for MRSA and vancomycin-resistant (VRE) carriage at admission and at day 7. Deep incisional and organ/space SSIs were also recorded.

Of 263 patients included in the study, 152 (58%) received cefazolin and 106 (40%) received vancomycin. At admission, the prevalence of MRSA carriage was 6.8%; it was 12% among patients with risk factors and 2.2% among patients with no risk factors (P = .002). At day 7 after surgery, there were 6 patients (2%) who had hospital-acquired MRSA, corresponding to 0.7% in the cefazolin group and 5% in the vancomycin group (P = .04); none of the MRSA isolates were resistant to glycopeptides. The rate of VRE carriage at admission was 0.4%. Three patients (1%) had acquired carriage of VRE (1 had E. faecium and 2 had E. faecalis); all 3 were in the cefazolin group (2% of patients) and none in the vancomycin group (P = .27). Eight SSIs (3%) occurred, 4% in the cefazolin group and 2% in the vancomycin group (P = .47).

This preliminary study demonstrates that cefazolin and vancomycin prophylaxis have similar impacts on the emergence of glycopeptide-resistant pathogens. Neither MRSA infection nor increased rates of SSI with other bacteria were observed in the vancomycin group, suggesting that a larger multicenter study should be initiated.

To measure the effect of cephazolin prophylaxis on the rate of surgical site infection among patients with clean surgical wounds, categorized by risk group, in a hospital undergoing renovation.

Randomized, double-blind clinical trial.

Saint Paul General Hospital, Coquimbo, Chile, during a period when it was undergoing significant interior remodeling.

General surgery patients who received antibiotic prophylaxis before clean wound surgery between March 2003 and May 2004 and a matched control group of patients who did not receive such prophylaxis.

A total of 303 patients participated in the study. The rate of infection among patients with an American Society of Anesthesiologists (ASA) classification of 1 in the prophylaxis group was 7.3%, whereas among ASA 1 patients in a no-prophylaxis control group it was 10.3% (P = .40). In the prophylaxis group, the ASA 2 and ASA 3 patients combined had an infection rate of 10.5%, whereas in the no-prophylaxis group these patients had a rate of 30.0% (relative risk, 0.33 [95% confidence interval, 0.58-0.96]; P = .03). Both the ASA 2 and ASA 3 patients were protected from infection by prophylaxis; these patients had 1.7 and 2.2 times, respectively, more risk of developing a surgical site infection than did ASA 1 patients after a clean surgical procedure, but the ASA 2 and ASA 3 patients who did not receive prophylaxis had 4.3 and 4.8 times, respectively, greater risk of infection (relative risk, 0.91 [95% confidence interval, 0.83-0.99]; P = .02). Prophylaxis significantly reduced the rate of infection in the ASA 2 and ASA 3 groups.

We recommend the use of antimicrobial prophylaxis with cephalosporins in ASA 2 and ASA 3 patients undergoing clean wound surgery during a period when significant renovations are being performed in the hospital.

To describe investigation of a tightly clustered outbreak of invasive group A streptococcal (GAS) disease associated with a high mortality rate in a long-term care facility (LTCF).

Cross-sectional carriage survey and epidemiologic investigation of LTCF resident and employee cohorts.

A 104-bed community LTCF between March 1 and April 7, 2004.

A cohort of LTCF residents with assigned beds at the time of the outbreak.

Reinforcement of standard infection control measures and receipt of chemoprophylaxis by GAS carriers.

Four confirmed and 2 probable GAS cases occurred between March 16 and April 1, 2004. Four case patients died. The final case occurred during the investigation, before the patient was determined to be a GAS carrier. No case occurred during the 6 months after the intervention. Disease was caused by type emm3 GAS; 16.5% of residents and 2.4% of employees carried the outbreak strain. Disease was clustered in 1 quadrant of the LTCF and associated with nonintact skin. GAS disease or carriage was associated with having frequent personal visitors.

Widespread carriage of a virulent GAS strain likely resulted from inadequate infection control measures. Enhanced infection control and targeted prophylaxis for GAS carriers appeared to end the outbreak. In addition to employees, regular visitors to LTCFs should be trained in hand hygiene and infection control because of the potential for extended relationships over time, leading to interaction with multiple residents, and disease transmission in such residential settings. Specific attention to prevention of skin breaks and proper wound care may prevent disease. The occurrence of a sixth case during the investigation suggests urgency in addressing severe, large, or tightly clustered outbreaks of GAS infection in LTCFs.

To assess the performance and limitations of a reprocessing protocol for nonlumen electrophysiology catheters by testing the sterility of reprocessed devices and defining the maximum number of reprocessing cycles sustainable by the device in hygienically safe conditions.

Simulated use, reprocessing, and testing of the catheters.

Microbiology and virology department of a public health diagnostic laboratory.

Seventy-three catheters were collected after clinical use on patients. The first group of devices was tested for sterility after 1 cycle of reprocessing. By the repetition of simulated use (blood inoculated with bacteria) and reprocessing (decontamination, cleaning, and hydrogen peroxide gas plasma sterilization), we obtained 39 sample devices reprocessed 2 times, 26 reprocessed 3 times, 28 reprocessed 4 times, 36 reprocessed 5 times, and 22 reprocessed 6 times. Devices were cultured for 28 days in trypticase soy broth.

We tested 208 catheters with 6 cycles of reprocessing and 4 inoculated bacteria species. No devices tested positive for the inoculated strains until the fourth cycle of reprocessing. One of 35 catheters showed the growth of the inoculated strain Bacillus subtilis after 5 cycles of reprocessing, and 1 of 22 catheters showed growth of this organism 6 cycles. After the second reprocessing, 7 of 36 devices showed growth of gram-negative bacteria other than the strain inoculated.

Reprocessing according to the reprocessing protocol was insufficient to guarantee device sterility after 5 reuses. Cleaning with enzymatic solution revealed good cleaning properties with efficient bioburden reduction. Storage intervals of longer than 24 hours during reprocessing should be avoided to limit contamination or bacterial overgrowth. Technical considerations suggest the introduction of reprocessing procedures only in hospitals with considerable workloads.