The economic benefits of surgical site infection prevention in adults: a systematic review

BACKGROUND

Surgical site infections (SSIs) present a significant burden to healthcare and patients in terms of excess length of stay, distress, disability and death. SSI risk and the associated economic burden may be reduced through adherence to prevention guidelines although the irreducible minimum is unclear.

AIM

To evaluate the methods used to estimate the cost-effectiveness of prevention strategies for all SSIs.

METHODS

PubMed, Medline, CINAHL, and UK National Health Service Economic Evaluation Database were searched from inception to January 2020 to identify English language economic evaluation studies, embedded economic evaluations, and studies with some analysis in relation to cost and benefit in adult patients receiving surgical care in any setting. Risk of bias was assessed using two published checklists.

FINDINGS

Thirty-two studies involving 24,043 participants were included. Most studies evaluated SSI prevention in orthopaedic surgeries. Antibiotic prophylaxis, screening, treating, or decolonization of meticillin-resistant Staphylococcus aureus and surgical wound closure were the main methods evaluated. Methods ranged from cost-analyses to cost-effectiveness and cost-utility analyses. Synthesis of results was not possible due to heterogeneity. All studies reported some economic benefit associated with preventing SSI; however, measures of benefit were not reported consistently and the quality of studies was low to moderate. Limited evidence in relation to SSI impact on quality of life was identified.

CONCLUSION

Current evidence in relation to the economic benefits of SSI prevention is limited. Further robust studies that utilize sound economic and epidemiological methods are required to inform future investment decisions in SSI prevention.

Burden of surgical site infections in the Netherlands: cost analyses and disability-adjusted life years

BACKGROUND

Surgical site infections (SSIs) are associated with morbidity, mortality and costs.

AIM

To identify the burden of (deep) SSIs in costs and disability-adjusted life years (DALYs) following colectomy, mastectomy and total hip arthroplasty (THA) in the Netherlands.

METHODS

A retrospective cost-analysis was performed using 2011 data from the national SSI surveillance network PREZIES. Sixty-two patients with an SSI (exposed) were matched to 122 patients without an SSI (unexposed, same type of surgery). Patient records were studied until 1 year after SSI diagnosis. Unexposed patients were followed for the same duration. Costs were calculated from the hospital perspective (2016 price level), and cost differences were tested using linear regression analyses. Disease burden was estimated using the Burden of Communicable Disease in Europe Toolkit of the European Centre for Disease Prevention and Control. The SSI model was specified by type of surgery, with country- and surgery-specific parameters where possible.

FINDINGS

Attributable costs per SSI were €21,569 (THA), €14,084 (colectomy) and €1881 (mastectomy), mainly caused by prolonged length of hospital stay. National hospital costs were estimated at €10 million, €29 million and €0.6 million, respectively. National disease burden was greatest for SSIs following colectomy (3200 DALYs/year, 150 DALYs/100 SSIs), while individual disease burden was highest following THA (1200 DALYs/year, 250 DALYs/100 SSIs). For mastectomy, these DALYs were <1. The total cost of DALYs for the three types of surgery exceeded €88 million.

CONCLUSION

Depending on the type of surgery, SSIs cause a significant burden, both economically and in loss of years in full health. This underlines the importance of appropriate infection prevention and control measures.

Prevalence of MRSA colonization in an adult urban Indian population undergoing orthopaedic surgery

INTRODUCTION

Orthopaedic surgery is technically demanding, implant dependant and expensive. Infection translates into a prolonged morbidity and long-term use of antibiotics. The most common organism involved in osteo-articular infections is Staphylococcus aureus, and colonizes the anterior nares of 25-30% of the population. Carriers are at higher risk for staphylococcal infections after invasive medical or surgical procedures. Prevalence of methicillin resistant Staphylococcus aureus (MRSA) has not been assessed in patients admitted for orthopaedic surgery in the Indian setting.

AIM

To assess the preoperative prevalence of MRSA colonization in adult patients undergoing orthopaedic surgery in urban India.

MATERIALS AND METHODS

This is a retrospective analysis of patients from 2009 to 2013. A total of 1550 patients admitted for orthopaedic surgery were preoperatively screened with nasal and axillary swabs for MRSA. Swab-positive patients were treated with intranasal mupirocin ointment for 3 days followed by a repeat swab. A record was made of hospitalization in the year prior to surgery and the occurrence of surgical site infection (SSI).

RESULTS

A total of 690 males and 860 females had been screened for MRSA using an inexpensive kit costing 500 Indian rupees. For MRSA, 7/1550 (0.45%) nasal swabs were positive. No patient since 2009 has had a SSI with MRSA.

CONCLUSION

MRSA screening prior to orthopaedic surgery is a valuable and cost effective preoperative investigation even though the incidence is low. Mupirocin is effective in clearing MRSA from the nares and maybe used for 3 days to obtain elimination of the bacteria.

An economic evaluation of two interventions for the prevention of post-surgical infections in cardiac surgery

OBJECTIVE

To conduct a cost-effectiveness analysis that compares two prophylactic protocols for treating post-surgical infections in cardiac surgery.

METHODS

A cost effectiveness analysis was done by using a decision tree to compare two protocols for prophylaxis of post-surgical infections (Protocol A: Those patient with positive test to methicillin-resistant Staphylococcus aureus (MRSA) colonization received muripocin (twice a day during a two-week period), with no follow-up verification. Those who tested negative did not receive the prophylaxis treatment; Protocol B: all patients received the mupirocin treatment). The number of post-surgical infections averted was the measure of effectiveness from the health system's perspective, 30 days following the surgery. The incidence of infections and complications was obtained from two cohorts of patients who underwent cardiac surgery Hospital. The times for applying the two protocols were validated by experts. They cost were calculated from the hospital's analytical accounting management system and Pharmaceutical Service. Only direct costs were taken into account, no discount rates were applied. Incremental cost-effectiveness ratio (ICER) was calculated. A probabilistic sensitivity analysis was performed.

RESULTS

A total of 1118 patients were included (721 in Protocol A and 397 in Protocol B). No statistically significant differences were found in age, sex, diabetes, exitus or length of hospital stay between the two protocols. In the control group the rate of infection was 15.3%, compared with 11.3% in the intervention group. Protocol B proves to be more effective and at a lower cost, yielding an ICER of €32,506.

CONCLUSION

Universal mupirocin prophylaxis against surgical site infections (SSI) in cardiac surgery as a dominant strategy, because it shows a lower incidence of infections and cost savings, versus the strategy to treat selectively patients according to their test results prior screening.

Strategies to prevent surgical site infections in acute care hospitals: 2014 update

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format designed to assist acute care hospitals in implementing and prioritizing their surgical site infection (SSI) prevention efforts. This document updates “Strategies to Prevent Surgical Site Infections in Acute Care Hospitals,”1 published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.2

Preventing surgical site infections: a randomized, open-label trial of nasal mupirocin ointment and nasal povidone-iodine solution

BACKGROUND

Treatment of Staphylococcus aureus colonization before surgery reduces risk of surgical site infection (SSI). The regimen of nasal mupirocin ointment and topical chlorhexidine gluconate is effective, but cost and patient compliance may be a barrier. Nasal povidone-iodine solution may provide an alternative to mupirocin.

METHODS

We conducted an investigator-initiated, open-label, randomized trial comparing SSI after arthroplasty or spine fusion in patients receiving topical chlorhexidine wipes in combination with either twice daily application of nasal mupirocin ointment during the 5 days before surgery or 2 applications of povidone-iodine solution into each nostril within 2 hours of surgical incision. The primary study end point was deep SSI within the 3 months after surgery.

RESULTS

In the modified intent-to-treat analysis, a deep SSI developed after 14 of 855 surgical procedures in the mupirocin group and 6 of 842 surgical procedures in the povidone-iodine group (P = .1); S. aureus deep SSI developed after 5 surgical procedures in the mupirocin group and 1 surgical procedure in the povidone-iodine group (P = .2). In the per protocol analysis, S. aureus deep SSI developed in 5 of 763 surgical procedures in the mupirocin group and 0 of 776 surgical procedures in the povidone-iodine group (P = .03).

CONCLUSIONS

Nasal povidone-iodine may be considered as an alternative to mupirocin in a multifaceted approach to reduce SSI.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01313182.

Costs of hospital-acquired infection and transferability of the estimates: a systematic review

Hospital-acquired infections (HAIs) present a substantial problem for healthcare providers, with a relatively high frequency of occurrence and considerable damage caused. There has been an increase in the number of cost-effectiveness and cost-savings analyses of HAI control measures, and the quantification of the cost of HAI (COHAI) is necessary for such calculations. While recent guidelines allow researchers to utilize COHAI estimates from existing published literature when evaluating the economic impact of HAI control measures, it has been observed that the results of economic evaluations may not be directly applied to other jurisdictions due to differences in the context and circumstances in which the original results were produced. The aims of this study were to conduct a systematic review of published studies that have produced COHAI estimates from 1980 to 2006 and to evaluate the quality of these estimates from the perspective of transferability. From a total of 89 publications, only eight papers (9.0%) had a high level of transferability in which all components of costs were described, data for costs in each component were reported, and unit costs were estimated with actual costing. We also did not observe a higher citation level for studies with high levels of transferability. We feel that, in order to ensure an appropriate contribution to the infection control program decision-making process, it is essential for researchers who estimate COHAI, analysts who use COHAI estimates for decision-making, as well as relevant journal reviewers and editors to recognize the importance of a transferability paradigm.

Cost effectiveness of local collagen-gentamicin as prophylaxis for sternal wound infections in different risk groups

OBJECTIVES

In a randomized trial addition of local collagen-gentamicin in the sternal wound reduced the rate of sternal wound infection (SWI) to about 50% compared to intravenous prophylaxis alone. The aim of the present study was to evaluate the economic rationale for its use in every-day clinical practice. This includes the question whether high-risk groups that may have particular benefit should be identified.

DESIGN

For each patient with SWI in the trial the costs attributable to the SWI were calculated. Risk factors for SWI were identified and any heterogeneity of the effect of the prophylaxis examined.

RESULTS

The mean cost of a SWI was about 14500 Euros. A cost effectiveness analysis showed that the prophylaxis was cost saving. The positive net balance was even higher in risk groups. Assignment to the control group, overweight, diabetes, younger age, mammarian artery use, left ventricular ejection fraction <35% and longer operation time were independent risk factors for infection.

CONCLUSION

The addition of local collagen-gentamicin to intravenous antibiotic prophylaxis was dominant, i.e. resulted in both lower costs and fewer wound infections.

The effect of surgical site infection on older operative patients

OBJECTIVES

To determine the effect of surgical site infection (SSI) on mortality, duration of hospitalization, and hospital cost in older operative patients.

DESIGN

Retrospective matched-outcomes study.

SETTING

Eight hospitals, including Duke University Medical Center, and seven community hospitals.

PARTICIPANTS

Patients aged 65 and older undergoing surgery from 1991 to 2003. Cases were defined as patients who developed deep incisional or organ or space SSI; controls were operative patients who did not develop SSI. Controls were frequency matched to cases according to type and year of operative procedure and to hospital in a 1:1 ratio.

MEASUREMENTS

Mortality, duration of hospitalization (including re-admissions), and hospital charges for the 90 days after surgery.

RESULTS

One thousand three hundred thirty-seven patients were enrolled in the study: 561 cases with SSI and 576 controls without SSI. In cases, the most common SSI pathogen was Staphylococcus aureus (n=275, 51.6%). Of S. aureus isolates, 58.2% were methicillin resistant. One hundred sixteen subjects died within 90 days of surgery (8.6%). In multivariable analysis, SSI was associated with greater mortality risk (odds ratio (OR)=3.51, 95% confidence interval (CI)=2.20-5.59), 2.9 times longer postoperative hospitalization (95% CI=2.61-3.13), and 1.9 times greater hospital charges (95% CI=1.78-2.10).

CONCLUSION

In elderly operative patients, SSI was associated with almost 4 times greater mortality, a mean attributable duration of hospitalization after surgery of 15.7 days (95% CI=13.9-17.6) and mean attributable hospital charges of $43,970 (95% CI=$31,881-56,060).

Strategies to prevent surgical site infections in acute care hospitals

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections. The intent of this document is to highlight practical recommendations in a concise format designed to assist acute care hospitals to implement and prioritize their surgical site infection (SSI) prevention efforts. Refer to the Society for Healthcare Epidemiology of America/Infectious Diseases Society of America “Compendium of Strategies to Prevent Healthcare-Associated Infections” Executive Summary and Introduction and accompanying editorial for additional discussion.

1. Burden of SSIs as complications in acute care facilities.

a. SSIs occur in 2%-5% of patients undergoing inpatient surgery in the United States.

b. Approximately 500,000 SSIs occur each year.

2. Outcomes associated with SSI

a. Each SSI is associated with approximately 7-10 additional postoperative hospital days.

b. Patients with an SSI have a 2-11 times higher risk of death, compared with operative patients without an SSI.

i. Seventy-seven percent of deaths among patients with SSI are direcdy attributable to SSI.

c. Attributable costs of SSI vary, depending on the type of operative procedure and the type of infecting pathogen; published estimates range from $3,000 to $29,000.

i. SSIs are believed to account for up to $10 billion annually in healthcare expenditures.

1. Definitions

a. The Centers for Disease Control and Prevention National Nosocomial Infections Surveillance System and the National Healthcare Safety Network definitions for SSI are widely used.

b. SSIs are classified as follows (Figure):

i. Superficial incisional (involving only skin or subcutaneous tissue of the incision)

ii. Deep incisional (involving fascia and/or muscular layers)

iii. Organ/space

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.

Underresourced hospital infection control and prevention programs: penny wise, pound foolish?

OBJECTIVES

To estimate the cost of healthcare-associated infections (HAIs) in a network of 28 community hospitals and to compare this sum to the amount budgeted for infection control programs at each institution and for the entire network.

DESIGN

We reviewed literature published since 1985 to estimate costs for specific HAIs. Using these estimates, we determined the costs attributable to specific HAIs in a network of 28 hospitals during a 1-year period (January 1 through December 31, 2004). Cost-saving models based on reductions in HAIs were calculated.

SETTING

Twenty-eight community hospitals in the southeastern region of the United States.

RESULTS

The weight-adjusted mean cost estimates for HAIs were $25,072 per episode of ventilator-associated pneumonia, $23,242 per nosocomial blood stream infection, $10,443 per surgical site infection, and $758 per catheter-associated urinary tract infection. The median annual cost of HAIs per hospital was $594,683 (interquartile range [IQR], $299,057-$1,287,499). The total annual cost of HAIs for the 28 hospitals was greater than $26 million. Hospitals budgeted a median of $129,000 (IQR, $92,500-$200,000) for infection control; the median annual cost of HAIs was 4.6 (IQR, 3.4-8.0) times the amount budgeted for infection control. An annual reduction in HAIs of 25% could save each hospital a median of $148,667 (IQR, $74,763-$296,861) and could save the group of hospitals more than $6.5 million.

CONCLUSIONS

The economic cost of HAIs in our group of 28 study hospitals was enormous. In the modern age of infection control and patient safety, the cost-control ratio will become the key component of successful infection control programs.

Staphylococcus aureus, the major pathogen in orthopaedic and cardiac surgical site infections: a literature review

Due to the increasing number of orthopaedic and cardiac procedures, these units are considered as high-risk areas because of the potentially serious consequences of surgical site infections (SSI), primarily caused by Staphylococcus aureus. The goal of this review was to evaluate the impact of S. aureus on the incidence of SSI in these high risk wards. Studies were identified by a search on the MEDLINE literature using the following mesh terms: S. aureus, cardiac, orthopaedic, surgery, SSI. Beside, data from different surveillance systems were also included. Overall, biological investigation was performed only on a small proportion of identified SSIs. Of those identified, S. aureus represented the most common pathogen accounting for approximately 20% of all SSIs. Of the 59,274 hip prostheses reported from the HELICS surveillance network, S. aureus formed 48.6% of the pathogens (416 bacteria isolated). Similarly, it represented 43.7% of pathogens after coronary artery bypass grafting. Although S. aureus turned out to be the major pathogen, this work identifies the relative lack of knowledge on the overall incidence of S. aureus infections and on the impact of this pathogenic agent when taking into consideration the degree of wound contamination and category of SSI. There is a need for more detailed information on the role of S. aureus in the burden of surgical site infections and consequently how to establish multiple approach prevention programs.

Preoperative use of mupirocin for the prevention of healthcare-associated Staphylococcus aureus infections: a cost-effectiveness analysis

OBJECTIVE

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.

METHODS

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 of mupirocin treatment, 51% (8%-75%); mupirocin treatment cost, 48.36 US Dollars (24.18-57.74 US Dollars); and hospital costs of bloodstream infection, 25,128 US Dollars (6,194-40,211 US Dollars), pneumonia, 18,366 US Dollars (5,574-28,952 US Dollars), and surgical site infection 16,256 US Dollars (5,119-22,553 US Dollars). Widespread use of mupirocin has been associated with high levels of mupirocin resistance; therefore, a broad range of estimates for efficacy was tested in the sensitivity analysis.

PATIENTS

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

RESULTS

Both the screen-and-treat and treat-all strategies were cost saving, saving 102 US Dollars per patient screened and 88 US Dollars per patient treated, respectively. In 1-way sensitivity analyses, the model was robust with respect to all data inputs except for the efficacy of mupirocin 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 US Dollars, or nursing compensation was greater than 64.21 US Dollars per hour.

CONCLUSION

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.

Impact of prophylactic mupirocin for radical esophagectomy

The preoperative intranasal application of mupirocin significantly decreases the rate of nosocomial S. aureus infections among patients who are S. aureus carriers. However, it remains unclear whether the routine preoperative use of mupirocin would reduce postoperative S. aureus infections, especially methicillin-resistant Staphylococcus aureus (MRSA) infections, and who would benefit from the prophylactic use of mupirocin. Ninety-six consecutive patients who had undergone elective radical esophagectomy with right thoracotomy and laparotomy were evaluated. Fifty-one patients were given 2% mupirocin calcium ointment 3 times daily over 3 consecutive days before surgery. Uni- and multivariate analyses were performed to identify factors affecting the following three issues: postoperative MRSA infection, postoperative pneumonia, and the length of postoperative hospital stay. In univariate analyses, the preoperative application of mupirocin significantly reduced MRSA infection, postoperative pneumonia, and length of postoperative hospital stay. Multivariate analyses indicated significant associations between mupirocin administration and reductions in both MRSA infection and postoperative pneumonia, but not in length of postoperative hospital stay. Radical esophagectomy with right thoracotomy and laparotomy for esophageal carcinoma warranted the preoperative prophylactic administration of mupirocin in order to reduce postoperative infectious complications from MRSA. Its routine use for such a high-risk procedure is entirely reasonable.

Perioperative intranasal mupirocin for the prevention of surgical-site infections: systematic review of the literature and meta-analysis

OBJECTIVE

To review the evidence evaluating perioperative intranasal mupirocin for the prevention of surgical-site infections according to type of surgical procedure.

DESIGN

Systematic review and meta-analysis of published clinical trials.

SETTING

Studies included were either randomized clinical trial or prospective trials at a single institution that measured outcomes both before and after an institution-wide intervention (before-after trial). In all studies, intervention and control groups differed only by the use of perioperative intranasal mupirocin in the intervention group.

PATIENTS

Patients undergoing general or nongeneral surgery (eg, cardiothoracic surgery, orthopedic surgery, and neurosurgery).

MAIN OUTCOME MEASURE

Risk of surgical-site infection following perioperative intranasal mupirocin versus usual care.

RESULTS

Three randomized and four before-after trials met the inclusion criteria. No reduction in surgical-site infection rate was seen in randomized general surgery trials (summary estimates: 8.4% in the mupirocin group and 8.1% in the control group; relative risk [RR], 1.04; 95% confidence interval [CI95], 0.81 to 1.33). In nongeneral surgery, the use of mupirocin was associated with a reduction in surgical-site infection in randomized trials (summary estimates: 6.0% in the mupirocin group and 7.6% in the control group; RR, 0.80; CI95, 0.58 to 1.10) and in before-after trials (summary estimates: 1.7% in the mupirocin group and 4.1% in the control group; RR, 0.40; CI95, 0.29 to 0.56).

CONCLUSIONS

Perioperative intranasal mupirocin appears to decrease the incidence of surgical-site infection when used as prophylaxis in nongeneral surgery. Given its low risk and low cost, use of perioperative intranasal mupirocin should be considered in these settings.

The role of nasal carriage in Staphylococcus aureus infections

Staphylococcus aureus is a frequent cause of infections in both the community and hospital. Worldwide, the increasing resistance of this pathogen to various antibiotics complicates treatment of S aureus infections. Effective measures to prevent S aureus infections are therefore urgently needed. It has been shown that nasal carriers of S aureus have an increased risk of acquiring an infection with this pathogen. The nose is the main ecological niche where S aureus resides in human beings, but the determinants of the carrier state are incompletely understood. Eradication of S aureus from nasal carriers prevents infection in specific patient categories-eg, haemodialysis and general surgery patients. However, recent randomised clinical trials in orthopaedic and non-surgical patients failed to show the efficacy of eliminating S aureus from the nose to prevent subsequent infection. Thus we must elucidate the mechanisms behind S aureus nasal carriage and infection to be able to develop new preventive strategies. We present an overview of the current knowledge of the determinants (both human and bacterial) and risks of S aureus nasal carriage. Studies on the population dynamics of S aureus are also summarised.

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.

New approaches to reduce Staphylococcus aureus nosocomial infection rates: treating S. aureus nasal carriage

BACKGROUND

Nosocomial infections cause significant patient morbidity and mortality. The 2.5 million nosocomial infections that occur each year cost the US healthcare system $5 million to $10 million. Staphylococcus aureus has long been recognized as an important pathogen in human disease and is the most common cause of nosocomial infections.

OBJECTIVE

To describe the epidemiology of S. aureus nosocomial infections that are attributable to patients' endogenous colonization.

DATA SOURCES

Review of the English-language literature and a MEDLINE search (as of September 1997).

DATA SYNTHESIS

The ecologic niche of S. aureus is the anterior nares. The prevalence of S. aureus nasal carriage is approximately 20-25%, but varies among different populations, and is influenced by age, underlying illness, race, certain behaviors, and the environment in which the person lives or works. The link between S. aureus nasal carriage and development of subsequent S. aureus infections has been established in patients on hemodialysis, on continuous ambulatory peritoneal dialysis, and those undergoing surgery. S. aureus nasal carriers have a two-to tenfold increased risk of developing S. aureus surgical site or intravenous catheter infections. Thirty percent of 100% of S. aureus infections are due to endogenous flora and infecting strains were genetically identical to nasal strains. Three treatment strategies may eliminate nasal carriage: locally applied antibiotics or disinfectants, systemic antibiotics, and bacterial interference. Among these strategies, locally applied or systemic antibiotics are most commonly used. Nasal ointments or sprays and oral antibiotics have variable efficacy and their use frequently results in antimicrobial resistance among S. aureus strains. Of the commonly used agents, mupirocin (pseudomonic acid) ointment has been shown to be 97% effective in reducing S. aureus nasal carriage. However, resistance occurs when the ointment has been applied for a prolonged period over large surface areas.

CONCLUSIONS

Given the importance of S. aureus nosocomial infections and the increased risk of S. aureus nasal carriage in patients with nosocomial infections, investigators need to study cost-effective strategies to prevent certain types of nosocomial infections or nosocomial infections that occur in specific settings. One potential strategy is to decrease S. aureus nasal carriage among certain patient populations.