Is the Burden ofStaphylococcus aureusAmong Patients With Surgical-Site Infections Growing?

Methicillin-resistant staphylococcus aureus nosocomial infection has a distinct epidemiological position and acts as a marker for overall hospital-acquired infection trends

An ongoing healthcare debate is whether controlling hospital-acquired infection (HAI) from methicillin-resistant Staphylococcus aureus (MRSA) will result in lowering the global HAI rate, or if MRSA will simply be replaced by another pathogen and there will be no change in overall disease burden. With surges in drug-resistant hospital-acquired pathogens during the COVID-19 pandemic, this remains an important issue. Using a dataset of more than 1 million patients in 51 acute care facilities across the USA, and with the aid of a threshold model that models the nonlinearity in outbreaks of diseases, we show that MRSA is additive to the total burden of HAI, with a distinct 'epidemiological position', and does not simply replace other microbes causing HAI. Critically, as MRSA is reduced it is not replaced by another pathogen(s) but rather lowers the overall HAI burden. The analysis also shows that control of MRSA is a benchmark for how well all non-S. aureus nosocomial infections in the same hospital are prevented. Our results are highly relevant to healthcare epidemiologists and policy makers when assessing the impact of MRSA on hospitalized patients. These findings further stress the major importance of MRSA as a unique cause of nosocomial infections, as well as its pivotal role as a biomarker in demonstrating the measured efficacy (or lack thereof) of an organization's Infection Control program.

In vitro and in vivo evaluation of gentamicin sulphate-loaded PLGA nanoparticle-based film for the treatment of surgical site infection

The study focuses on the in vitro and in vivo evaluation of the developed gentamicin sulphate (GS)-loaded poly lactic-co-glycolic acid (PLGA) nanoparticle (PNP)-based pullulan film (PNP-F). Sterilization being an essential pre-requisite for the dosage form was carried out using ethylene oxide. Post-sterilization, PNP-F was evaluated for mechanical properties, percentage drug loading, antimicrobial effectiveness study, test for sterility and in vitro dissolution study using Strat-M® membrane. In vitro dissolution study revealed that GS gradually released from PNP-F and the highest cumulative percentage drug release was found to be 86.76 ± 0.03% at 192 h. Wound healing assay was performed to study the effect of PNP-F over migratory potential of dermal fibroblast cells (NIH-3T3) in the presence of micro-organisms, Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA). PNP-F inhibited the growth of PA and SA, allowing the growth of fibroblast cells indicating its suitability for application. In vivo study of surgical site was performed by superficial incision model in Wistar rats. Measurement of in vivo incision healing confirmed faster wound healing in the incision which received PNP-F compared to marketed cream containing GS. Graphical abstract.

Staphylococcus aureus: A predominant cause of surgical site infections in a rural healthcare setup of Uttarakhand

Introduction:

Surgical site infections (SSIs) represent the second most common type of healthcare-associated infections and remain a relatively common postoperative complication and the most common reason for readmission after surgery. SSIs have dire implications for the surgeon, patient, and institution which often require prolonged treatment, impose an economic burden and double the risk of patient mortality. Staphylococcus aureus is currently the most common cause of SSIs causing as many as 37% of cases of SSIs in community hospitals with methicillin-resistant S. aureus (MRSA) of particular concern.

Materials and Methods:

This cross-sectional study was conducted from January 2014 to December 2014 in a rural tertiary care hospital of Pauri Garhwal district of Uttarakhand state, India. Samples were collected using sterile cotton swabs from 269 patients clinically diagnosed with SSIs and were processed as per standard microbiological techniques. Antimicrobial susceptibility testing was done using a modified Kirby-Bauer disc diffusion method.

Results:

Out of 1294 patients, 269 (20.8%) were found to have SSIs and samples were collected from them. Out of a total of 269 samples, 258 (95.9%) yielded bacterial growth and 267 bacterial isolates were obtained. S. aureus (45.3%) was the commonest organism followed by Escherichia coli (13.9%), Pseudomonas aeruginosa (6.7%), and Proteus species (4.9%). Antimicrobial profile of S. aureus revealed maximum sensitivity to rifampicin, linezolid, teicoplanin, vancomycin, and amikacin whereas ampicillin, cefazolin, and gentamicin were found to be least sensitive.

Conclusion:

S. aureus played a predominant role in the etiology of SSIs in this hospital with MRSA being a major concern as the treatment options for such resistant strains are limited. Reduction in SSI rates can lead to both better clinical outcomes for patients and cost savings for hospitals. Adherence to strict infection control measures, maintenance of proper hand hygiene and optimal preoperative, intraoperative, and postoperative patient care can surely reduce the incidence of SSIs. A multifaceted approach involving the surgical team, microbiologist, and the infection control team is required to provide quality surgical services.

Multiple Cross Displacement Amplification Coupled With Nanoparticles-Based Lateral Flow Biosensor for Detection of Staphylococcus aureus and Identification of Methicillin-Resistant S. aureus

Staphylococcus aureus (S. aureus), including methicillin-resistant S. aureus (MRSA), is one of the most important human pathogens, which is responsible for bacteremia, soft-tissue infections, and food poisoning. Hence, multiple cross displacement amplification (MCDA) is employed to detect all S. aureus strains, and differentiates MRSA from methicillin-sensitive S. aureus. Multiplex MCDA (m-MCDA), which targets the nuc gene (S. aureus-specific gene) and mecA gene (encoding penicillin-binding protein-2′), could detect S. aureus strains and identify MRSA within 85 min. Detection of the m-MCDA products is achieved using disposable lateral flow biosensors. A total of 58 strains, including various species of Gram-positive and Gram-negative strains, are used for evaluating and optimizing m-MCDA assays. The optimal amplification condition is found to be 63°C for 40 min, with detection limits at 100 fg DNA/reaction for nuc and mecA genes in the pure cultures, and 10 CFU/tube for nuc and mecA genes in the blood samples. The analytical specificity of m-MCDA assay is of 100%, and no cross-reactions to non-S. aureus strains are produced according to the specificity testing. Particularly, two additional components, including AUDG enzyme and dUTP, are added into the m-MCDA amplification mixtures, which are used for eliminating the unwanted results arising from carryover contamination. Thus, the m-MCDA technique appears to be a simple, rapid, sensitive, and reliable assay to detect all S. aureus strains, and identify MRSA infection for appropriate antibiotic therapy.

Surgical Site Infection Research Opportunities

Much has been done to identify measures and modify risk factors to decrease the rate of surgical site infection (SSI). Development of the Centers for Disease Control and Prevention (CDC) Core recommendations for the prevention of SSI revealed evidence gaps in six areas: Parenteral antimicrobial prophylaxis, glycemic control, normothermia, oxygenation, antiseptic prophylaxis, and non-parenteral antimicrobial prophylaxis. Using a modified Delphi process, seven SSI content experts identified nutritional status, smoking, obesity, surgical technique, and anemia as additional areas for SSI prevention research. Post-modified Delphi process Staphylococcus aureus colonization and SSI definition and surveillance were also deemed important topic areas for inclusion. For each topic, research questions were developed, and 10 were selected as the final SSI research questions.

Surgical Site Infection by Methicillin Resistant Staphylococcus aureus- on Decline?

INTRODUCTION

Surgical Site Infection (SSI) is the most common healthcare associated infection that could be averted by antibiotics prophylaxis against the probable offending organisms. As Staphylococcus aureus has been playing a substantial role in the aetiology of SSIs, Methicillin Resistant Staphylococcus aureus (MRSA) happens to be a problem while dealing with the postoperative wound infection.

AIM

To determine the prevalence of SSI caused by MRSA and the antibiotic sensitivity pattern of MRSA.

MATERIALS AND METHODS

A cross-sectional study was conducted at Nil Ratan Sircar Medical College, Kolkata, West Bengal from July 2009 to December 2012. A total of 19,359 surgical procedures were done of which 3003 culture positive SSIs have been documented. The clinical samples were collected from patients of both sexes and all ages suspected to be suffering from SSI from different specialities. Samples were processed according to CLSI, 2007 guidelines. The isolated strains of Staphylococcus aureus were screened for MRSA by detection of resistance to Cefoxitin disc (zone of inhibition was ≤21 mm) and slidex staph latex agglutination tests were done on cefoxitin resistant strains to spot phenotypic expression of mec A gene. Then PCR was performed for detection of mecA gene. Antibiotic sensitivity test was done following Kirby Bauer technique.

RESULTS

In this 3½ year study, 1049 Staphylococcus aureus (34.93%) were reported from 3003 cases of SSI followed by Escherichia coli (20.34%), Klebsiella spp. (18.08%), Pseudomonas spp. (7.99%), Acinetobacter spp. (7.49%) respectively. Among the Staphylococcus aureus, 267 strains were derived as MRSA (25.45%). MRSA were isolated from 167 (62.54%) male patients and 100 (37.45%) female patients having surgical site infections. Inpatients and outpatients distribution of MRSA were 235 (88.01%) and 32 (11.98%) respectively. Majority of the MRSA cases were reported from Surgery (12.49%) and Orthopaedics (11.85%) departments in the age group above 75 years (15.63%). The MRSA strains have been found to be 100% sensitive to linezolid and tigecycline followed by fucidin (92.51%), mupirocin (88.39%), levofloxacin (75.66%) and doxycycline (72.28%). No vancomycin resistant strains were detected, but 3 strains (1.12%) were found to be intermediately susceptible to it (VISA). Incidence of MRSA in SSI has been decreased by 15.17 % in 2012 in comparison to 2009. PCR revealed mecA gene was present in 96.25% of cefoxitin resistant Staphylococcus aureus strains.

CONCLUSION

Staphylococcus aureus being the predominant organism causing SSIs, MRSA needs the attention for its resistance to commonly used antibiotics in the hospital like penicillin, cephalosporin group of drugs. Regular monitoring of the MRSA, involved in the SSI of a particular setup is the basic requirement to trim down the incidence of the postoperative wound infections by proper antibiotic prophylaxis.

Pre-cesarean Staphylococcus aureus nasal screening and decolonization: a prospective randomized controlled trial

OBJECTIVE

Staphylococcus aureus (S. aureus) is a common pathogen in surgical site infections (SSIs). Mupirocin ointment is an effective treatment for nasal carriers. We aimed to investigate whether screening for nasal colonization of S. aureus and treating carriers prior to a cesarean section (CS) decreases the likelihood of SSI.

METHODS

This is a randomized controlled trial. All participants underwent nasal culture prior to the CS. Nasal carriers of S. aureus were treated with Mupirocin ointment according to a standardized protocol. In the control group, nasal cultures were obtained immediately prior to surgery and carriers were not treated.

RESULTS

We recruited 568 patients. Demographic characteristics were comparable between the groups. S. aureus nasal colonization rates were 20.1% and 14.9% in the intervention and control groups, respectively (p = 0.12). S. aureus eradication rate with Mupirocin treatment was 88%. SSI rates were similar in the intervention and control groups (13.1% versus 12.1%, respectively, p = 0.78) and in treated carriers, untreated carriers, and non-carriers (7.4% versus 13.0% versus 13.1%, respectively, p = 0.69). Previous CS was the only factor found to independently predict SSI (OR 2.5, CI 1.09-5.65 p = 0.029).

CONCLUSION

Pre-cesarean screening for nasal S. aureus carriage and decolonization does not appear to be an effective intervention in reducing SSI rates.

Deep Wound Infections After Pediatric Scoliosis Surgery

STUDY DESIGN

Retrospective clinical and radiographic review.

OBJECTIVE

The purpose of this study was to evaluate the characteristics of deep wound infection, as well as the potential factors that correlate to surgical site infection (SSI) in spine deformity surgery.

SUMMARY OF BACKGROUND DATA

Preventing SSIs in pediatric spinal deformity surgery is a crucial task. Recent data have shown that antibiotic-loaded allograft and properly timed preoperative antibiotic administration decrease SSIs. However, there remain controversies over the appropriate preoperative antibiotic selection.

METHODS

We reviewed 851 spinal deformity surgeries that took place at a single institution from 2006 to 2010. In particular, preoperative and postoperative characteristics of the deep wound infections were evaluated.

RESULTS

Twenty-four patients had SSIs. The mean age at surgery in the infected cohort was 14 years, mean length of surgery was 8 hours, and median estimated blood loss was 2,482 mL (%EBV: 66%). Approximately 67% of the infected patients had bowel/bladder incontinence, and 71% had prolonged intravenous access perioperatively. According to culture results, the most effective antibiotic to treat the infections was vancomycin. Preoperative antibiotics were administered within 30 minutes of incision (hospital protocol) in only 12.5% (p = .001) and within 1 hour of incision in 54% of the cases. The wound status within 3 days of surgery is as follows: 38% intact, 29% significant wound drainage, and 33% wound dehiscence. Methicillin-resistant Staphylococcus aureus (MRSA) and oxacillin-resistant Staphylococcus epidermidis were associated with intact wounds, whereas gram-negative pathogens were seen in dehisced or draining wounds (p < .001).

CONCLUSIONS

The authors showed that their cohort of patients with infection had a high rate of draining wounds, MRSA infections, administration of antibiotics more than 1 hour ahead of incision, and prolonged need for intravenous access after surgery. Efforts to mitigate these associations by using vancomycin prophylactically, doing meticulous wound closure to prevent drainage or dehiscence, and delivering antibiotics at an optimal time ahead of incision may lead to a decrease in infection rates in pediatric spinal surgery. Future prospective studies will be needed to validate this.

Variation in the Type and Frequency of Postoperative Invasive Staphylococcus aureus Infections According to Type of Surgical Procedure

Objective.

To determine the epidemiological characteristics of postoperative invasive Staphylococcus aureus infection following 4 types of major surgical procedures.

Design.

Retrospective cohort study.

Setting.

Eleven hospitals (9 community hospitals and 2 tertiary care hospitals) in North Carolina and Virginia.

Patients.

Adults undergoing orthopedic, neurosurgical, cardiothoracic, and plastic surgical procedures.

Methods.

We used previously validated, prospectively collected surgical surveillance data for surgical site infection and microbiological data for bloodstream infection. The study period was 2003 through 2006. We defined invasive S. aureus infection as either nonsuperficial incisional surgical site infection or bloodstream infection. Nonparametric bootstrapping was used to generate 95% confidence intervals (CIs). P values were generated using the Pearson x2 test, Student t test, or Wilcoxon rank-sum test, as appropriate.

Results.

In total, 81,267 patients underwent 96,455 procedures during the study period. The overall incidence of invasive S. aureus infection was 0.47 infections per 100 procedures (95% CI, 0.43–0.52); 227 (51%) of 446 infections were due to methicillin-resistant S. aureus. Invasive S. aureus infection was more common after cardiothoracic procedures (incidence, 0.79 infections per 100 procedures [95% CI, 0.62–0.97]) than after orthopedic procedures (0.37 infections per 100 procedures [95% CI, 0.32–0.42]), neurosurgical procedures (0.62 infections per 100 procedures [95% CI, 0.53–0.72]), or plastic surgical procedures (0.32 infections per 100 procedures [95% CI, 0.17¬0.47]) (P < .001). Similarly, S. aureus bloodstream infection was most common after cardiothoracic procedures (incidence, 0.57 infections per 100 procedures [95% CI, 0.43–0.72]; P < .001, compared with other procedure types), comprising almost three-quarters of the invasive S. aureus infections after these procedures. The highest rate of surgical site infection was observed after neurosurgical procedures (incidence, 0.50 infections per 100 procedures [95% CI, 0.42–0.59]; P < .001, compared with other procedure types), comprising 80% of invasive S. aureus infections after these procedures.

Conclusion.

The frequency and type of postoperative invasive S. aureus infection varied significantly across procedure types. The highest risk procedures, such as cardiothoracic procedures, should be targeted for ongoing preventative interventions.

Implementation of an Industrial Systems-Engineering Approach to Reduce the Incidence of Methicillin-ResistantStaphylococcus aureusInfection

Objective.

To measure the effectiveness of an industrial systems-engineering approach to a methicillin-resistantStaphylococcus aureus(MRSA) prevention program.

Design.

Before-after intervention study

Setting.

An intensive care unit (ICU) and a surgical unit that was not an ICU in the Pittsburgh Veterans Administration hospital

Patients.

Allpatientsadmittedtothe study units

Intervention.

We implemented an MRSA infection control program that consisted of the following 4 elements: (1) the use of standard precautions for all patient contact, with emphasis on hand hygiene; (2) the use of contact precautions for interactions with patients known to be infected or colonized with MRSA; (3) the use of active surveillance cultures to identify patients who were asymptomatically colonized with MRSA; and (4) use of an industrial systems-engineering approach, the Toyota Production System, to facilitate consistent and reliable adherence to the infection control program.

Results.

The rate of healthcare-associated MRSA infection in the surgical unit decreased from 1.56 infections per 1,000 patient-days in the 2 years before the intervention to 0.63 infections per 1,000 patient-days in the 4 years after the intervention (a 60% reduction;P= .003). The rate of healthcare-associated MRSA infection in the ICU decreased from 5.45 infections per 1,000 patient-days in the 2 years before to the intervention to 1.35 infections per 1,000 patient-days in the 3 years after the intervention (a 75% reduction;P= .001). The combined estimate for reduction in the incidence of infection after the intervention in the 2 units was 68% (95% confidence interval, 50%-79%;P< .001).

Conclusions.

Sustained reduction in the incidence of MRSA infection is possible in a setting where this pathogen is endemic. An industrial systems-engineering approach can be adapted to facilitate consistent and reliable adherence to MRSA infection prevention practices in healthcare facilities.

Proportions of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus in patients with surgical site infections in mainland China: a systematic review and meta-analysis

BACKGROUND

Sufficient details have not been specified for the epidemiological characteristics of Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus (MRSA) among surgical site infections (SSIs) in mainland China. This systematic review aimed to estimate proportions of S. aureus and MRSA in SSIs through available published studies.

METHODS

PubMed, Embase and four Chinese electronic databases were searched to identify relevant primary studies published between 2007 and 2012. Meta-analysis was conducted on the basis of logit-transformed metric for proportions of S. aureus and MRSA, followed by pre-defined subgroup meta-analysis. Random-effects meta-regression was also conducted to explore the impact of possible factors on S. aureus proportions.

RESULTS

106 studies were included, of which 38 studies involved MRSA. S. aureus accounted for 19.1% (95%CI 17.2-21.0%; I(2) = 84.1%) of all isolates in SSIs, which was roughly parallel to 18.5% in the United States (US) (P-value = 0.57) but significantly exceeded those calculated through the surveillance system in China (P-value<0.001). In subgroup analysis, S. aureus in patients with thoracic surgery (41.1%, 95%CI 26.3-57.7%; I(2) = 74.4%) was more common than in those with gynecologic surgery (20.1%, 95%CI 15.6-25.6%; I(2) = 33.0%) or abdominal surgery (13.8%, 95%CI 10.3-18.4%; I(2) = 70.0%). Similar results were found in meta-regression. MRSA accounted for 41.3% (95%CI 36.5-46.3%; I(2) = 64.6%) of S. aureus, significantly lower than that in the US (P-value = 0.001). MRSA was sensitive to vancomycin (522/522) and linezolid (93/94), while 79.9% (95%CI 67.4-88.4%; I(2) = 0%) and 92.0% (95%CI 80.2-97.0%; I(2) = 0%) of MRSA was resistant to clindamycin and erythromycin respectively.

CONCLUSION

The overall proportion of S. aureus among SSIs in China was similar to that in the US but seemed higher than those reported through the Chinese national surveillance system. Proportions of S. aureus SSIs may vary with different surgery types. Commonly seen in SSIs, MRSA tended to be highly sensitive to vancomycin and linezolid but mostly resistant to clindamycin and erythromycin.

Surgical site infections

Surgical site infections are a major contributor to morbidity and mortality in postsurgical care. Risk for surgical site infection is multifactorial and includes a host of microbial, patient-related, and procedure-related factors. Prevention of surgical infection relies on optimization of patient factors and use of a variety of evidence-based pharmacologic and nonpharmacologic measures. At the forefront of these measures is antimicrobial prophylaxis, which has been shown to be effective at reducing risk of surgical site infection. As guidelines for prevention of surgical site infection become increasingly complex and nuanced, surgical infection outcomes are increasing tied to quality outcome and performances measures.

Antibiotic prophylaxis and the prevention of surgical site infection

PURPOSE OF REVIEW

Surgical site infection (SSI) is one of the most common complications of surgery in both adults and children. The purpose of the present review is to highlight the progress in the understanding of SSIs and the current role of antimicrobial prophylaxis (AMP).

RECENT FINDINGS

An SSI is diagnosed by a constellation of clinical findings occurring within 30 days of surgery. Pathologic organisms responsible for the development of an SSI are mainly limited to Gram-positive bacteria. Two well documented risk factors for the development of SSI in children are wound classification by the Centers for Disease Control (CDC) and procedure duration. Administration of appropriate AMP prior to skin incision has been shown to reduce the incidence of SSI in selected procedures. However, there is a lack of consensus on which procedures in children require AMP.

SUMMARY

Improvement in the perioperative care of children has reduced both the incidence and outcomes of SSI. However, several controversies still exist in the use of AMP in children. Future work by pediatricians, pediatric surgeons, and pediatric infectious disease specialists will enable us to better understand the specific indications and appropriate AMP in children.

Prospective, open-label investigation of the pharmacokinetics of daptomycin during cardiopulmonary bypass surgery

As methicillin-resistant Staphylococcus aureus (MRSA) becomes more prevalent, vancomycin is becoming increasingly used as a prophylaxis against surgical-site infections for cardiothoracic surgeries. However, vancomycin administration can be challenging, and the pharmacokinetics of alternative antibiotics in this setting are poorly understood. The primary objective of this investigation was to describe the pharmacokinetics of daptomycin in patients undergoing coronary artery bypass graft surgery. We enrolled 15 patients undergoing coronary artery bypass surgery requiring cardiopulmonary bypass. Each subject was administered a single open-label dose of daptomycin (8 mg/kg of body weight) for surgical prophylaxis. Fourteen daptomycin plasma samples were collected. Safety outcomes between subjects who received daptomycin and 15 control subjects who received the standard-of-care antibiotic were compared. The mean maximal concentration of daptomycin (C(max)) was 84.4 ± 27.1 μg/ml; the mean daptomycin concentration during the cardiopulmonary bypass procedure was 33.2 ± 11.4 μg/ml and was 30.9 ± 12.7 μg/ml at sternum closure. Mean daptomycin concentrations at 12, 18, 24, and 48 h were 22.7 ± 9.7, 16.2 ± 8.2, 12.0 ± 4.7, and 3.5 ± 2.3 μg/ml, respectively. Mean daptomycin concentrations were consistently above the MIC at which 90% of the tested isolates are inhibited (MIC₉₀) for S. aureus and S. epidermidis during the cardiopulmonary bypass procedure. Daptomycin was not associated with surgical-site infections or differences in adverse events compared to findings for control subjects. We found that a single dose of daptomycin at 8 mg/kg was well tolerated and achieved adequate plasma concentrations against common pathogens associated with surgical-site infections after cardiothoracic surgery. Daptomycin may be considered an alternative surgical prophylaxis antibiotic for patients undergoing cardiothoracic bypass surgery who are unable to receive vancomycin.

Staphylococcal surgical site infections

Staphylococcus aureus is the leading cause of surgical site infections (SSI) in the United States. In particular, SSI caused by methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a devastating complication, leading to increased mortality rates, increased length of hospitalization, and increased costs. Proven strategies for prevention of SSI caused by S aureus include addressing modifiable risk factors and correct choice and timing of antimicrobial prophylaxis. Other strategies, including decolonization and the use of vancomycin, remain controversial.

CE-based detection of methicillin-resistant Staphylococcus aureus

Rapid and sensitive detection of methicillin-resistant Staphylococcus aureus is crucial for effective treatment and control of clinical infections caused by this bacterium. The goal of this study is to develop a CE-based detection method for multiplexed identification of a femA sequence specific for S. aureus and a unique mecA sequence encoding methicillin resistance. Blood samples spiked with known concentrations of bacteria were used for testing. Crude cell lysates were prepared by treating the spiked blood samples with DNazol Direct reagent and used as the template for isothermal amplification of mecA and femA genes. The amplified gene products then underwent a cycling probe reaction (CPR)-based assay to generate a short fluorophore-labeled oligonucleotide for detection in a CZE-LIF system. The assay enables a gene-specific fluorophore-labeled DNA-RNA-DNA chimeric probe to hybridize with complementary target in the presence of RNase H enzyme. The RNase H enzyme specifically cleaves probe RNA residues of the duplex, releasing a fluorophore fragment for detection and the target for recycling and hybridization with another chimeric probe. Intact and cleaved probe fragments were separated and detected using a CZE-LIF system. The limit of detection for isothermal amplification and CPR-CZE-LIF was approximately 10(4) colony-forming units of bacteria/mL of blood. This method accurately detects methicillin-resistant S. aureus within 3 h.

Poor functional status as a risk factor for surgical site infection due to methicillin-resistant Staphylococcus aureus

OBJECTIVE

To identify risk factors for surgical site infection (SSI) due to methicillin-resistant Staphylococcus aureus (MRSA).

DESIGN

Prospective case-control study.

SETTING

One tertiary and 6 community-based institutions in the southeastern United States.

METHODS

We compared patients with SSI due to MRSA with 2 control groups: matched uninfected surgical patients and patients with SSI due to methicillin-susceptible S. aureus (MSSA). Multivariable logistic regression was used to determine variables independently associated with SSI due to MRSA, compared with each control group.

RESULTS

During the 5-year study period, 150 case patients with SSI due to MRSA were identified and compared with 231 matched uninfected control patients and 128 control patients with SSI due to MSSA. Two variables were independently associated with SSI due to MRSA in both multivariable regression models: need for assistance with 3 or more activities of daily living (odds ratio [OR] compared with uninfected patients, 3.97 [95% confidence interval {CI}, 2.18-7.25]; OR compared with patients with SSI due to MSSA, 3.88 [95% CI, 1.91-7.87]) and prolonged duration of surgery (OR compared with uninfected patients, 1.98 [95% CI, 1.11-3.55]; OR compared with patients with SSI due to MSSA, 2.33 [95% CI, 1.17-4.62]). Lack of independence (ie, poor functional status) remained associated with an increased risk of SSI due to MRSA after stratifying by age.

CONCLUSIONS

Poor functional status was highly associated with SSI due to MRSA in adult surgical patients, regardless of age. A patient's level of independence can be easily determined, and this information can be used preoperatively to target preventive interventions.

Impact of an antimicrobial-impregnated gauze dressing on surgical site infections including methicillin-resistant Staphylococcus aureus infections

BACKGROUND

Surgical site infections (SSIs) are a common complication of surgery. Methicillin-resistant Staphylococcus aureus (MRSA) is a particularly troublesome infectious agent in this setting. SSIs contribute to increased morbidity and mortality, as well as increasing length of hospital stay and costs.

METHODS

Sterile plain gauze dressings were replaced institution-wide by a comparable sterile antimicrobial gauze dressing (AMD) impregnated with 0.2% polyhexamethylene biguaide. SSIs, and specifically MRSA-SSIs, were tracked for the 11-month periods before and after the dressing switch, using Centers for Disease Control and Prevention criteria.

RESULTS

Before the introduction of AMD, 101 SSIs occurred after 9372 surgical procedures (1.08%), 20 of which were identified as MRSA (0.21%). After introduction of AMD, 84 SSIs occurred after 10,202 surgical procedures (0.82%), representing a rate reduction of 24.07% (P = .035), with 11 identified as MRSA (0.11%), representing a reduction of 47.62% (P = .047). This reduction in SSIs represents an annual cost savings to the institution of $508,605.

CONCLUSION

A significant reduction in SSIs, and specifically MRSA-SSIs, resulted from a simple change from plain sterile gauze to a sterile comparable antimicrobial dressing. This change reduced morbidity and possibly mortality after surgery, shortened hospital stays, and reduced the costs of postsurgical care.