Surgical-site infection rates and risk factor analysis in coronary artery bypass graft surgery.

BACKGROUND: The Victorian Infection Control Surveillance Project (VICSP) is a multicenter collaborative surveillance project established by infection control practitioners. Five public hospitals contributed data for patients undergoing coronary artery bypass graft (CABG) surgery. OBJECTIVE: To determine the aggregate and comparative interhospital surgical-site infection (SSI) rates for patients undergoing CABG surgery and the risk factors for SSI in this patient group. METHOD: Each institution used standardized definitions of SSI, risk adjustment, and reporting methodology according to the National Nosocomial Infections Surveillance System of the Centers for Disease Control and Prevention. Data on potential risk factors were prospectively collected. RESULTS: For 4,474 patients undergoing CABG surgery, the aggregate SSI rate was 7.8 infections per 100 procedures (95% confidence interval [CI95], 7.0-8.5), with individual institutions ranging between 4.5 and 10.7 infections per 100 procedures. Multivariate risk factor analysis demonstrated age (odds ratio [OR], 1.02; CI95, 1.01-1.04; P < .001), obesity (OR, 1.8; CI95, 1.4-2.3; P < .001), and diabetes mellitus (OR, 1.6; CI95, 1.2-2.1; P < .001) as independent predictors of SSI. Three hundred thirty-four organisms were isolated from 296 SSIs. Of the total SSIs, methicillin-resistant Staphylococcus aureus was isolated from 32%, methicillin-sensitive S. aureus from 24%, gram-negative bacilli (eg, Enterobacter and Escherichia coli) from 18%, and miscellaneous organisms from the remainder. CONCLUSION: We documented aggregate and comparative SSI rates among five Victorian public hospitals performing CABG surgery and defined specific independent risk factors for SSI. VICSP data offer opportunities for targeted interventions to reduce SSI following cardiac surgery.     

Comparison of the National Surgical Site Infection surveillance data between The Netherlands and Germany: PREZIES versus KISS

As there has been increasing interest in comparing surgical site infection (SSI) rates between countries, we compared the SSI surveillance data for The Netherlands ('PREZIES') and Germany ('KISS'). Both surveillance systems have comparable protocols with many similar risk factors, including SSI definitions developed by the Centers for Disease Control and Prevention and optional postdischarge surveillance. Nine surgical procedure categories from several specialities were included, the reporting of which were similar, with respect to content and with enough data for proper comparison. Differences for the SSI data were found between PREZIES and KISS for duration of surgery, wound contamination class, American Society of Anesthesiologists physical status classification and the postoperative duration of hospitalization. A significantly higher superficial SSI rate was found for seven surgical procedures according to PREZIES and a higher deep SSI rate for five procedures. When considering only deep SSI during hospitalization, the differences in SSI rates were much smaller. Differences in intensity of postdischarge surveillance led to 34% of SSI being detected after discharge for PREZIES and 21% for KISS. In conclusion, even though similar infection surveillance protocols are used in The Netherlands and Germany, differences occurred in the implementation. Comparisons between countries are most reliable if only deep SSIs during hospitalization are taken into account, since these SSI are not affected by postdischarge surveillance and the diagnostic sensitivity for deep SSI is probably more alike between countries than for superficial SSI.     

Nasal carriage of Staphylococcus aureus is a major risk factor for surgical-site infections in orthopedic surgery.

OBJECTIVE: To determine the relative importance of different risk factors for the development of surgical-site infections (SSIs) in orthopedic surgery with prosthetic implants. DESIGN: In a cohort of 272 patients, the following possible risk factors were studied: age, gender, method of hair removal, duration of operation, surgeon, underlying illness, and nasal carriage of Staphylococcus aureus. Infections were recorded following the Centers for Disease Control criteria. The relation between risk factors and SSI was tested in univariate and multiple logistic regression analysis. SETTING: Community hospital in Breda, The Netherlands. RESULTS: 18 (6.6%) of 272 patients experienced SSI: 11 superficial and 7 deep SSI. These infections led in three cases to removal of the prosthesis and caused 286 extra days in hospital. The main causative pathogen was S aureus. In multiple logistic regression analysis, the following factors were independent risk factors for the development of SSI: high-level nasal carriage of S aureus (P=.04), male gender (P=.005), and surgeon 1 (P=.006). The only independent risk factor for SSI with S aureus was high-level nasal carriage of S aureus (P=.002). CONCLUSION: High-level nasal carriage of S aureus was the most important and only significant independent risk factor for developing SSI with S aureus.     

医院手术切口感染病原菌分布及耐药性分析

目的 分析医院手术切口感染病原菌的分布及耐药性,从循证医学的角度探讨手术切口感染的预防及干预对策.方法 回顾性调查医院手术切口感染患者的病案资料,细菌培养、鉴定按《全国临床检验操作规程》进行,药敏试验采用K-B法.结果 426株手术切口感染病原菌以革兰阴性杆菌为主,占60.56％,主要为铜绿假单胞、大肠埃希菌及鲍氏不动杆菌,占25.82％、13.15％及9.39％,其次是革兰阳性球菌,占36.15％,主要为金黄色葡萄球菌占23.00％,真菌占3.29％;病原菌均显示了较高的耐药性,耐甲氧西林金黄色葡萄球菌检出率为44.90％.结论 医院手术切口感染病原菌主要以革兰阴性杆菌为主,其次是革兰阳性球菌及真菌,且病原菌耐药情况较为严峻;加强外科手术切口医院感染的监测工作,有针对性地采取相关措施,预防手术切口感染的发生.     

Impact of postdischarge surveillance on the rate of surgical site infection after orthopedic surgery.

OBJECTIVE: To evaluate the impact of postdischarge surveillance on surgical site infection (SSI) rates after orthopedic surgery. SETTING: Nine hospitals participating in the Finnish Hospital Infection Program. PATIENTS: All patients who underwent hip or knee arthroplasty or open reduction of a femur fracture during 1999-2002. RESULTS: 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). CONCLUSIONS: 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.     

Surveillance for surgical site infection after hospital discharge: a surgical procedure-specific perspective.

OBJECTIVE: 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. DESIGN: Prospective surveillance study. SETTING: A surgical ward at a university teaching hospital in Italy. PATIENTS: A total of 264 surgical patients were included in the study. RESULTS: 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. CONCLUSIONS: 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.     

Pattern of Pathogens and Their Sensitivity Isolated from Surgical Site Infections at the Aga Khan University Hospital,Nairobi, Kenya

Background

In low income countries, surgical site infections (SSIs) are costly and impose a heavy and potentially preventable burden on both patients and healthcare providers. This study aimed to determine the occurrence of SSI, pathogens associated with SSI, the antibiogram of the causative pathogens and specific risk factors associated with SSI at the hospital.

Methods

Two hundred and sixty-eight respondents admitted for general surgical procedures (other than neurological and cardiothoracic surgeries) at the Aga Khan University Hospital were eligible to take part in the study. Post-surgery patients were observed for symptoms of infection. Follow ups were done through the consulting clinics, breast clinic and casualty dressing clinic by a team of surgeons. In cases of infection, pus swabs were collected for culture.

Results

SSI incidence rate was 7.0%, pathogens isolated from SSI included gram negative enteric bacilli and S. aureus which was the most prevalent bacterial isolate. Only one isolate of MRSA was found and all staphylococci were susceptible to Vancomycin. Preoperative stay ≥ 2 days and wound class were the risk factors associated with SSI.

Conclusion

The SSI incidence rates (7.0%) observed in this study were relatively lower than the ones documented in other studies in Kenya. S. aureus is the most prevalent pathogen associated with SSI. Similar to findings from other studies done in the region; prolonged hospital stay and dirty wounds were the risks associated with postsurgical sepsis at the hospital.     

Detection of postoperative surgical-site infections: comparison of health plan-based surveillance with hospital-based programs.

BACKGROUND: Review of health plan administrative data has been shown to be more sensitive than other methods for identifying postdischarge surgical-site infections (SSIs), but there has not been a direct comparison between this method and hospital-based surveillance for all infections, including those diagnosed before discharge. We compared these two methods for identifying SSIs following coronary artery bypass graft (CABG) procedures. METHODS: We studied 1,352 CABG procedures performed among members of one health plan from March 1993 through June 1997. Health plan administrative records were reviewed based on claims containing diagnoses or procedures suggestive of infection or outpatient dispensing of antibiotics appropriate for SSI. Hospital-based surveillance information was also reviewed. SSI rates were calculated based on the total events identified by either mechanism. RESULTS: Postdischarge information was reviewed for 328 (85%) of 388 procedures. SSIs were confirmed in 167 patients (13% overall risk of confirmed SSI; range, 3% to 14% in the 5 hospitals). The overall sensitivity of hospital-based surveillance was 49.7% (83 of 167), and that of health plan data was 71.8% (120 of 167). There was no significant difference among hospitals in the sensitivity of either surveillance mechanism. CONCLUSIONS: Surveillance based on health plan data identified more postoperative infections, including those occurring before discharge, than did hospital-based surveillance. Screening administrative data and pharmacy activity may be an important adjunct to SSI surveillance, allowing efficient comparison of hospital-specific rates. Interpretation of differences among hospitals' infection rates requires case mix adjustment and understanding of variations in hospitals' discharge diagnosis coding practices.     

Surgical site infection after surgery to repair femoral neck fracture: a French multicenter retrospective study.

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

Impact of postdischarge surveillance on surgical-site infection rates for coronary artery bypass procedures.

OBJECTIVE: To assess the influence of postdischarge infection surveillance on risk-adjusted surgical-site infection rates for coronary artery bypass graft (CABG) procedures. DESIGN: Prospective surveillance of surgical-site infections after CABG. SETTING: Tertiary-care referral hospital. METHODS: Data on surgical-site infections were collected for 1,324 CABG procedures during 27 months. They were risk adjusted and analyzed according to the surgical surveillance protocol of the National Nosocomial Infections Surveillance (NNIS) System of the Centers for Disease Control and Prevention, with and without postdischarge data. RESULTS: Data were available for 96% of the patients. Of the 88 surgical-site infections, 28% were identified prior to discharge and 72% postdischarge. More chest than harvest-site infections were identified (46% vs 11%) prior to discharge, and more harvest-site than chest infections were identified in the outpatient setting (42% vs 14%). The surgical-site infection rate for patients stratified under risk index 1, calculated without postdischarge surveillance, was 2.9%; when compared with that of the NNIS System, the P value was .29. When postdischarge surveillance was included, the surgical-site infection rate was 4.9% and statistically significant when compared with that of the NNIS System (P = .007). For patients stratified under risk index 2, the rates with and without postdischarge surveillance were 11.7% and 10.0%, respectively; when compared with the NNIS System rates, the P values were .000008 and .0006, respectively. CONCLUSIONS: Only 28% of the surgical-site infections would have been detected if surveillance had been limited to hospital stay. Postdischarge surveillance identified more surgical-site infections among risk index 1 patients. Hospitals with comprehensive postdischarge surveillance after CABG procedures are likely to record higher surgical-site infection rates than those that do not perform such surveillance .     

Impact of postdischarge surveillance on surgical site infection rates for several surgical procedures: results from the nosocomial surveillance network in The Netherlands.

OBJECTIVE: To compare the number of surgical site infections (SSIs) registered after hospital discharge with respect to various surgical procedures and to identify the procedures for which postdischarge surveillance (PDS) is most important. DESIGN: Prospective SSI surveillance with voluntary PDS. Recommended methods for PDS in the Dutch national nosocomial surveillance network are addition of a special registration card to the outpatient medical record, on which the surgeon notes clinical symptoms and whether a patient developed an SSI according to the definitions; an alternative method is examination of the outpatient medical record. SETTING: Hospitals participating in the Dutch national nosocomial surveillance network between 1996 and 2004. RESULTS: We collected data on 131,798 surgical procedures performed in 64 of the 98 Dutch hospitals. PDS was performed according to one of the recommended methods for 31,134 operations (24%) and according to another active method for 32,589 operations (25%), and passive PDS was performed for 68,075 operations (52%). Relatively more SSIs were recorded after discharge for cases in which PDS was performed according to a recommended method (43%), compared with cases in which another active PDS method was used (30%) and cases in which passive PDS was used (25%). The highest rate of SSI after discharge was found for appendectomy (79% of operations), followed by knee prosthesis surgery (64%), mastectomy (61%), femoropopliteal or femorotibial bypass (53%), and abdominal hysterectomy (53%). CONCLUSIONS: For certain surgical procedures, most SSIs develop after discharge. SSI rates will be underestimated if no PDS is performed. We believe we have found a feasible and sensitive method for PDS that, if patients routinely return to the hospital for a postdischarge follow-up visit, might be suitable for use internationally.     

外科手术部位感染病原菌分布

目的了解外科患者手术部位感染的病原菌分布. 方法总结分析全国医院感染监控网资料中的手术部位感染病原学资料. 结果金黄色葡萄球菌、表皮葡萄球菌、肠球菌属分别占分离病原体的12.69%、8.08%、6.49%;大肠埃希菌、铜绿假单胞菌、肠杆菌属、克雷伯菌属分别占19.32%、9.69%、7.88%、5.65%;白色念珠菌和非白色念珠菌分别占1.51%和2.19%;由表浅切口到器官腔隙感染,G 菌和真菌的比例逐渐增加. 结论常见的手术部位感染病原体为大肠埃希菌、金黄色葡萄球菌、铜绿假单胞菌、表皮葡萄球菌、肠杆菌属、肠球菌属、克雷伯菌属,需加强对手术部位感染及其病原菌和耐药性的监测.     

An alternative scoring system to predict risk for surgical site infection complicating coronary artery bypass graft surgery.

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

Validation of coronary artery bypass graft surgical site infection surveillance data from a statewide surveillance system in Australia.

OBJECTIVE: To measure the accuracy and determine the positive predictive value (PPV) and negative predictive value (NPV) of data submitted to a statewide surveillance system for identifying surgical site infection (SSI) complicating coronary artery bypass graft (CABG) surgery. DESIGN: Retrospective review of hospital medical records comparing SSI data with surveillance data submitted by infection control consultants (ICCs). SETTING: Victorian Hospital Acquired Infection Surveillance System (VICNISS) Coordinating Centre in Victoria, Australia. PATIENTS: All patients reported to have an SSI following CABG surgery and a random sample of approximately 10% of patients reported not to have an SSI following CABG surgery. RESULTS: The VICNISS ascertainment rate for CABG procedures in Victoria was 95%. One hundred sixty-nine medical records were reviewed, and reviewers agreed with ICCs about 46 (96%) of the patients reported as infected by the ICCs and 31 (91%) of the patients identified with a sternal SSI by the ICCs. In one-third of SSIs, the depth of SSI documented by ICCs was discordant with that documented by the reviewers. Disagreement about patients with donor site SSI was frequent. When the review findings were used as the reference standard, the PPV for ICC-reported SSI was 96% (95% confidence interval [CI], 86%-99%), and the NPV was 97% (95% CI, 92%-99%). For ICC-reported sternal SSI, the PPV was 91% (95% CI, 76%-98%) and the NPV was 98% (95% CI, 94%-100%). CONCLUSIONS: There was broad agreement on the number of infected patients and the number of patients with sternal SSI. However, discordance was frequent with respect to the depth of sternal SSI and the identification of donor site SSI. We recommend modifications to the methodology for National Nosocomial Infection Surveillance System-based surveillance for SSI following CABG surgery.     

Infections after coronary artery bypass graft surgery in Victorian hospitals--VICNISS Hospital Acquired Infection Surveillance

OBJECTIVE: To establish a surveillance program reporting surgical site infection rates after coronary artery bypass graft surgery (CABGS) in Victorian public hospitals. METHODS: The VICNISS Coordinating Centre was established in 2002 to implement and co-ordinate a standardised surveillance system for hospital-acquired infections in acute care Victorian public hospitals. Using validated definitions and methodology from the Centers for Disease Control and Prevention's National Nosocomial Infection Surveillance (NNIS) program, data on risk-adjusted surgical site infection (SSI) rates were collected and submitted to the Coordinating Centre for collation and reporting. RESULTS: Six large Melbourne metropolitan hospitals contributed data for CABGS for the period 11 November 2002 to 30 June 2004, comprising a total of 3,482 patient records. Of 3,398 complete records, the aggregate SSI rates per 100 procedures for NNIS risk category 1 and 2 were 4.4 (95% Cl 3.7-5.3) and 6.0 (95% Cl 4.5-7.8) respectively. The deep sternal SSI rates were 0.6 (95% Cl 0.4-1.3) and 0.5 (95% Cl 0.5-2.4 for patients in risk category 1 and 2 respectively. The most common pathogen identified was Staphylococcus aureus. CONCLUSION: This early data from VICNISS demonstrates similar CABGS SSI rates to those reported by NNIS in the USA, but higher than reported by the German Nosocomial Infection Surveillance System. IMPLICATIONS: The adoption of a statewide, co-ordinated surveillance program using validated internationally accepted methodologies allows hospitals to benchmark their infection rates against aggregate local and international data and to examine infection prevention interventions.     

Severe surgical site infection in community hospitals: epidemiology, key procedures, and the changing prevalence of methicillin-resistant Staphylococcus aureus.

OBJECTIVE: To characterize the epidemiology of severe (ie, nonsuperficial) surgical site infection (SSI) in community hospitals. METHODS: SSI data were collected prospectively at 26 community hospitals in the southeastern United States. Two analyses were performed: (1) a study of the overall prevalence rates of SSI and the prevalence rates of SSI due to specific pathogens in 2005 at all participating hospitals and (2) a prospective study of consecutive surgical procedures at 9 of the 26 community hospitals from 2000 through 2005. RESULTS: In 2005, a total of 1,010 SSIs occurred after 89,302 procedures (prevalence rate, 1.13 infections per 100 procedures). Methicillin-resistant S. aureus (MRSA) was the pathogen most commonly recovered (from 175 SSIs). Trend data from 2000 through 2005 demonstrated that the prevalence rate of MRSA SSI almost doubled during this period, increasing from 0.12 infections per 100 procedures (95% confidence interval [CI], 0.12-0.13) to 0.23 infections per 100 procedures (95% CI, 0.22-0.24) (P<.0001). In adjusted analysis, MRSA SSI was significantly more prevalent at the end of the study period than at the beginning (prevalence rate ratio, 1.48 [95% CI, 1.36-1.61]; P<.0001). CONCLUSIONS: MRSA was the pathogen that most commonly caused SSI in our network of community hospitals during 2005. The prevalence of MRSA SSI has increased significantly over the past 6 years.     

Random effect modelling of patient-related risk factors in orthopaedic procedures: results from the Dutch nosocomial infection surveillance network 'PREZIES'

In the Dutch surveillance for surgical site infections (SSIs), data from 70277 orthopaedic procedures with 1895 SSIs were collected between 1996 and 2003. The aims of this study were: (1) to analyse the trends in SSIs associated with Gram-positive and Gram-negative bacteria; (2) to estimate patient-related risk factors for deep and superficial SSIs after all orthopaedic procedures, with special attention to primary total hip arthroplasty (THA); and (3) to analyse inherent differences in infection risk between hospitals. A random effect model was used to estimate the odds ratios of patient-related risk factors for developing an SSI, and to describe the distribution of the most widespread bacterial species responsible for SSIs among hospitals. Gram-positive organisms, mainly staphylococci, were the main cause of both deep (84.0%) and superficial SSIs (69.1%) after orthopaedic procedures. The percentage of SSIs after THA caused by coagulase-negative staphylococci decreased over the surveillance period, while the contribution of Staphylococcus aureus increased. Temporary elevations in the incidence of the most widespread pathogen species were observed within hospitals. Patient-related factors such as the National Nosocomial Infections Surveillance System risk index or age had little effect on the predictive power of the random effect models. This study underlines the usefulness of a random effect model, which adjusts risk estimates for random variation between hospitals, in a multicentre study on risk factors for SSIs.     

Surgical-site infections following cesarean section in an Estonian university hospital: postdischarge surveillance and analysis of risk factors.

OBJECTIVES: To evaluate a multi-method approach to postdischarge surveillance of surgical-site infections (SSIs) and to identify infection rates and risk factors associated with SSI following cesarean section. DESIGN: Cross-sectional survey. SETTING: Academic tertiary-care obstetric and gynecology center with 54 beds. PATIENTS: All women who delivered by cesarean section in Tartu University Women's Clinic during 2002. METHODS: Infections were identified during hospital stay or by postdischarge survey using a combination of telephone calls, healthcare worker questionnaire, and outpatient medical records review. SSI was diagnosed according to the criteria of the Centers for Disease Control and Prevention National Nosocomial Infections Surveillance System. RESULTS: The multi-method approach gave a follow-up rate of 94.8%. Of 305 patients, 19 (6.2%; 95% confidence interval [CI95], 3.8-9.6) had SSIs. Forty-two percent of these SSIs were detected during postdischarge surveillance. We found three variables associated with increased risk for developing SSI: internal fetal monitoring (odds ratio [OR], 16.6; CI95, 2.2-125.8; P = .007), chorioamnionitis (OR, 8.8; CI95, 1.1-69.6; P = .04), and surgical wound classes III and IV (OR, 3.8; CI95, 1.2-11.8; P = .02). CONCLUSIONS: The high response rate validated the effectiveness of this kind of surveillance method and was most suitable in current circumstances. A challenge exists to decrease the frequency of internal fetal monitoring and to treat chorioamnionitis as soon as possible.     

Surgical-site infection due to Staphylococcus aureus among elderly patients: mortality, duration of hospitalization, and cost.

OBJECTIVES: To examine the impact of surgical-site infection (SSI) due to Staphylococcus aureus on mortality, duration of hospitalization, and hospital charges among elderly surgical patients and the impact of older age on these outcomes by comparing older and younger patients with S. aureus SSI. DESIGN: A nested cohort study. SETTING: A 750-bed, tertiary-care hospital and a 350-bed community hospital. PATIENTS: Ninety-six elderly patients (70 years and older) with S. aureus SSI were compared with 2 reference groups: 59 uninfected elderly patients and 131 younger patients with S. aureus SSI. RESULTS: Compared with uninfected elderly patients, elderly patients with S. aureus SSI were at risk for increased mortality (odds ratio [OR], 5.4; 95% confidence interval [CI95], 1.5-20.1), postoperative hospital-days (2.5-fold increase; CI95, 2.0-3.1), and hospital charges (2.0-fold increase; CI95, 1.7-2.4; dollar 41,117 mean attributable charges per SSI). Compared with younger patients with S. aureus SSI, elderly patients had increased mortality (adjusted OR, 2.9; CI95, 1.1-7.6), hospital-days (9 vs 13 days; P = .001), and median hospital charges (dollar 45,767 vs dollar 85,648; P < .001). CONCLUSIONS: Among elderly surgical patients, S. aureus SSI was independently associated with increased mortality, hospital-days, and cost. In addition, being at least 70 years old was a predictor of death in patients with S. aureus SSI.     

Surgical-site infections at Kilimanjaro Christian Medical Center

A five-month prospective survey of surgical-site infections (SSI) was conducted in the department of general surgery at Kilimanjaro Christian Medical Center, Tanzania. SSI were classified according to Centers for Disease Control and Prevention (CDC) criteria and identified by bedside surveillance and post-discharge follow-up. This study showed that 77 (19.4%) of the patients developed SSI. Twenty-eight (36.4%) of these infections were apparent only after discharge from hospital. Eighty-seven percent of those who developed SSI had received antibiotic prophylaxis. Significant risk factors for developing SSI during hospital stay were: operations classified as contaminated or dirty, operations lasting for more than 50 min and the length of preoperative stay. The only significant risk factor for those who developed SSI after discharge was having undergone a clean-contaminated operation. Staphylococcus aureus was the most frequently isolated micro-organism followed by Escherichia coli and Klebsiella spp., most of which were multi-resistant. An exception was S. aureus where 54.5% of the isolates were fully susceptible. The incidence of SSI and the prevalence of antibiotic resistance in this teaching and tertiary care hospital are high. The risk factors were similar to those reported from countries with more resources. The findings suggest that infection prevention measures, particularly antibiotic prophylaxis, should be re-evaluated.