Prior Methicillin-resistant Staphylococcus Aureus Infection Research Articles

When is vancomycin prophylaxis necessary? Risk factors for MRSA surgical site infection.

The 2022 SHEA/IDSA/APIC guidance for surgical site infection (SSI) prevention recommends reserving vancomycin prophylaxis to patients who are methicillin-resistant Staphylococcus aureus (MRSA) colonized. Unfortunately, vancomycin prophylaxis remains common due to the overestimation of MRSA risk and the desire to cover MRSA in patients with certain healthcare-associated characteristics. To optimize vancomycin prophylaxis, we sought to identify risk factors for MRSA SSI. This was a single-center, case-control study of patients with a postoperative SSI after undergoing a National Healthcare Safety Network operative procedure over eight years. MRSA SSI cases were compared to non-MRSA SSI controls. Forty-two demographic, medical, and surgical characteristics were evaluated. Of the 441 patients included, 23 developed MRSA SSIs (rate = 5.2 per 100 SSIs). In the multivariable model, we identified two independent risk factors for MRSA SSI: a history of MRSA colonization or infection (OR, 9.0 [95% CI, 1.9-29.6]) and hip or knee replacement surgery (OR, 3.8 [95% CI, 1.3-9.9]). Hemodialysis, previous hospitalization, and prolonged hospitalization prior to the procedure had no measurable association with odds of MRSA SSI. Patients with prior MRSA colonization or infection had 9-10 times greater odds of MRSA SSI and patients undergoing hip and knee replacement had 3-4 times greater odds of MRSA SSI. Healthcare-associated characteristics, such as previous hospitalization or hemodialysis, were not associated with MRSA SSI. Our findings support national recommendations to reserve vancomycin prophylaxis for patients who are MRSA colonized, as well as those undergoing hip and knee replacement, in the absence of routine MRSA colonization surveillance.

Using Methicillin-Resistant Staphylococcus aureus Nasal Screens to Rule Out Methicillin-Resistant S aureus Pneumonia in Surgical Intensive Care Units

IntroductionThe methicillin-resistant Staphylococcus aureus (MRSA) polymerase chain reaction (PCR) has a high negative predictive value (NPV). We aimed to understand if there was a difference in the NPV of the MRSA screen in surgical intensive care units (ICUs) and to determine its role in antibiotic de-escalation. MethodsWe performed a single-center, retrospective cohort study of adults with a positive respiratory culture and MRSA nasal PCR admitted to a surgical ICU from 2016 to 2019. Patients were stratified by surgical ICU: cardiothoracic/cardiovascular intensive care unit (CVICU) or transplant/acute care surgery intensive care unit (ACS-ICU). Our primary outcome was the NPV of MRSA screen. Secondary outcome was the duration of empiric MRSA-targeted therapy. ResultsWe analyzed 61 patients: 42.6% (n = 26) ACS-ICU and 57.4% (n = 35) CVICU. There were no differences in age, comorbidities, prior MRSA infection, recent antibiotic use, immunocompromised status, or renal replacement therapy. At pneumonia diagnosis, more patients in the ACS-ICU were hospitalized ≥5 d (65.4% versus 8.6%, P < 0.0001) and more patients in the CVICU were in septic shock (88.6% versus 34.5%, P < 0.0001) and thrombocytopenic (40% versus 11.5%, P = 0.02). NPV of the PCR was similar (ACS-ICU: 0.92 [0.75-0.98], CV-ICU 0.89 [0.73-0.96]). On multivariable linear regression, the CVICU was associated with longer empiric therapy (β 1.5, 95% CI 0.8-2.3, P < 0.0001), as was hospitalization for ≥5 d (β 0.73, 95% CI 0.06-1.39, P = 0.03). ConclusionsThe MRSA nasal PCR screen has a high NPV for ruling out MRSA pneumonia in critically ill surgical patients. However, patients in the CVICU and patients hospitalized ≥5 d had a longer time to de-escalation of MRSA-targeted therapy, potentially due to higher clinical risk profile.

1367. Reduced Ceftaroline Susceptibility Among Invasive MRSA Isolates at a Tertiary Children’s HospitalReduced Ceftaroline Susceptibility Among Invasive MRSA Isolates at a Tertiary Children’s Hospital

BackgroundThe emergence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) in the late 1990s-early 2000s complicated the empiric management of suspected staphylococcal infection in children. Rising clindamycin resistance rates in many communities adds further to management challenges. Ceftaroline, an anti-MRSA cephalosporin, represents an attractive therapy option. Little data are available, however, regarding the frequency of reduced susceptibility (RS) to ceftaroline among MRSA isolates from a general pediatric population.MethodsIsolates were selected from an ongoing S. aureus surveillance study at Texas Children’s Hospital. Invasive MRSA isolates from 2015-2018 were included. Isolates were initially screened for ceftaroline RS with E-test; all isolates with a ceftaroline E-test MIC ≥ 1.5µg/ml underwent ceftaroline broth dilution. Ceftaroline RS was regarded as an MIC ≥ 2 µg/ml; full ceftaroline resistance was defined as an MIC ≥ 8 μg/ml. Accessory gene regulator (agr) groups were characterized by PCR.Results201 viable isolates were included. The ceftaroline MIC50 and MIC90 were 0.5 and 1 µg/ml, respectively (Figure 1). Six isolates had MIC ≥ 2 µg/ml (2.9%) with two having MIC ≥ 8 µg/ml (0.9%). All ceftaroline RS isolates were from healthcare associated infections. Ceftaroline RS isolates were more often associated with clindamycin-resistance and agr group II (Figure 2). Infections with ceftaroline RS were associated with central venous lines, recent ICU admission, preceding antibiotic exposure (specifically cephalosporins) and prior MRSA infection. One subject with MRSA CLABSI had a ceftaroline susceptible MRSA infection followed < 1 month later by a ceftaroline resistant infection (MIC =32 μg/ml); the isolates were identical by PFGE. Only 3 subjects had previously received ceftaroline, none of which subsequently developed a ceftaroline RS isolate.Figure 1. Ceftaroline MIC Distribution Figure 2. Clinical And Microbiologic Associations with Reduced Ceftaroline Susceptibility ConclusionCeftaroline RS occurs in 2.9% of invasive MRSA isolates in children and is most prominent among healthcare-associated infections. These isolates were associated with clindamycin resistance and agr group II. While ceftaroline RS is rare among invasive MRSA infections, the lack of preceding ceftaroline exposure is concerning and warrants careful surveillance.Disclosures Sheldon L. Kaplan, MD, Allergan (Research Grant or Support)Pfizer (Grant/Research Support) Jonathon C. McNeil, MD, Allergan (Research Grant or Support, Allergan provided ceftaroline powder for use in studies described in this abstract)

Factors associated with persistent colonisation with methicillin-resistant Staphylococcus aureus.

We conducted a prospective cohort study between 1 January 2010 and 31 December 2012 at five adult and paediatric academic medical centres to identify factors associated with persistent methicillin-resistant Staphylococcus aureus (MRSA) colonisation. Adults and children presenting to ambulatory settings with a MRSA skin and soft tissue infection (i.e. index cases), along with household members, performed self-sampling for MRSA colonisation every 2 weeks for 6 months. Clearance of colonisation was defined as two consecutive negative sampling periods. Subjects without clearance by the end of the study were considered persistently colonised and compared with those who cleared colonisation. Of 243 index cases, 48 (19·8%) had persistent colonisation and 110 (45·3%) cleared colonisation without recurrence. Persistent colonisation was associated with white race (odds ratio (OR), 4·90; 95% confidence interval (CI), 1·38-17·40), prior MRSA infection (OR 3·59; 95% CI 1·05-12·35), colonisation of multiple sites (OR 32·7; 95% CI 6·7-159·3). Conversely, subjects with persistent colonisation were less likely to have been treated with clindamycin (OR 0·28; 95% CI 0·08-0·99). Colonisation at multiple sites is a risk factor for persistent colonisation and may require more targeted decolonisation efforts. The specific effect of clindamycin on MRSA colonisation needs to be elucidated.

Risk factors for methicillin-resistant Staphylococcus aureus skin and soft tissue infection in MRSA-colonized patients discharged from a Veterans Affairs hospital.

Currently, limited studies have quantified the risk of methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTIs) for MRSA-colonized patients on discharge from hospital. Our retrospective, case-control study identified independent risk factors for the development of MRSA SSTIs among such patients detected by active MRSA nasal screening in an acute care hospital by PCR on admission, and bacteriological cultures on discharge. Cases were MRSA-colonized patients aged ⩾18 years who developed a MRSA SSTI post-discharge and controls were those who did not develop a MRSA SSTI post-discharge. Controls were matched to cases by length of follow-up (±10 days) for up to 18 months. Potential demographic and clinical risk factors for MRSA infection were identified using electronic queries and manual chart abstraction; data were compared by standard statistical tests and variables with P values ⩽0·05 in bivariable analysis were entered into a logistic regression model. Multivariable analysis demonstrated prior hospital admission within 12 months (P = 0·02), prior MRSA infection (P = 0·05), and previous myocardial infarction (P = 0·01) were independently predictive of a MRSA SSTI post-discharge. Identification of MRSA colonization upon admission and recognition of risk factors could help identify a high-risk population that could benefit from MRSA SSTI prevention strategies.

Predictors and costs of surgical site infections in patients with endometrial cancer

ObjectiveTechnological advances in surgical management of endometrial cancer (EC) may allow for novel risk modification in surgical site infection (SSI). MethodsPerioperative variables were abstracted from EC cases surgically staged between January 1, 1999, and December 31, 2008. Primary outcome was SSI, as defined by American College of Surgeons National Surgical Quality Improvement Program. Counseling and global models were built to assess perioperative predictors of superficial incisional SSI and organ/space SSI. Thirty-day cost of SSI was calculated. ResultsAmong 1369 EC patients, 136 (9.9%) had SSI. In the counseling model, significant predictors of superficial incisional SSI were obesity, American Society of Anesthesiologists (ASA) score >2, preoperative anemia (hematocrit <36%), and laparotomy. In the global model, significant predictors of superficial incisional SSI were obesity, ASA score >2, smoking, laparotomy, and intraoperative transfusion. Counseling model predictors of organ/space SSI were older age, smoking, preoperative glucose >110mg/dL, and prior methicillin-resistant Staphylococcus aureus (MRSA) infection. Global predictors of organ/space SSI were older age, smoking, vascular disease, prior MRSA infection, greater estimated blood loss, and lymphadenectomy or bowel resection. SSI resulted in a $5447 median increase in 30-day cost. ConclusionsOur findings are useful to individualize preoperative risk counseling. Hyperglycemia and smoking are modifiable, and minimally invasive surgical approaches should be the preferred surgical route because they decrease SSI events. Judicious use of lymphadenectomy may decrease SSI. Thirty-day postoperative costs are considerably increased when SSI occurs.

Perioperative management of neurosurgical patients with methicillin-resistant Staphylococcus aureus

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has posed a challenge in the treatment of neurosurgical patients. The authors investigated the impact of MRSA colonization and infection in the neurosurgical population at a community-based, tertiary care referral center. Hospitalized patients under the care of the Kaiser Permanente inpatient neurosurgery service were prospectively entered into a database. In Phase I of the study, 492 consecutive patients were followed. Per hospital policy, the 260 patients from this group who were admitted to the intensive care unit (ICU) underwent screening for MRSA based on nasal swab cultures and a review of their medical history for prior MRSA infections. These patients were designated as either MRSA positive (17 patients, 6.5% of screened patients) or MRSA negative (243 patients). The 232 patients admitted to non-ICU nursing units did not undergo MRSA screening and were designated as unscreened. In Phase II of the study, the authors reviewed 1005 neurosurgical admissions and completed a detailed chart review in 62 MRSA-positive patients (6.2%). Eleven patients received nonoperative treatment. Five patients presented with community-acquired neurosurgical infections, and the causative organism was MRSA in 3 cases. Forty-six patients underwent 55 procedures, and the authors reviewed their perioperative management. In Phase I of the study, the authors found that for the MRSA-positive, MRSA-negative, and unscreened groups, the rates of postoperative neurosurgical wound infections caused by all pathogens were 23.5, 4.1, and 1.3%, respectively. For MRSA wound infections, the rates were 23.5, 0.8, and 0%, respectively. In Phase II, patients with MRSA were noted to have the following clinical features: male sex in 63%, a malignancy in 39.1%, diabetes in 34.8%, prior MRSA infection in 21.7%, immunosuppressed state in 17.4%, and a traumatic injury in 15.2%. The rate of postoperative neurosurgical wound infection in patients who received MRSA-specific prophylactic antibiotic therapy (usually vancomycin) was 7.4% (27 procedures) compared with 32.1% (28 procedures) in patients who received the standard treatment (usually cefazolin) (p = 0.04). Wound care for ICU patients was standardized for postoperative Days 0-7 with chlorhexidine cleaning at bandage changes at 3-day intervals. Wound cultures from neurosurgical site infections in patients with prior MRSA colonization or infection grew MRSA in 7 of 11 patients. Neurosurgical patients identified with MRSA colonization or a prior history of MRSA infections benefit from specific perioperative care, including prophylactic antibiotics active against MRSA (such as vancomycin) and postoperative wound care with coverings and chlorhexidine antisepsis to reduce MRSA wound colonization.

Empirical Antimicrobial Therapy for Bloodstream Infection Due to Methicillin-Resistant Staphylococcus aureus: No Better than a Coin Toss

Despite the high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection in the hospital, the proportion of patients with MRSA bacteremia who receive appropriate empirical therapy remains suboptimal. To investigate the proportion of patients with MRSA bloodstream infection (BSI) who received appropriate empirical antibiotic therapy and to identify risk factors associated with receipt of appropriate empirical therapy. We studied a cohort of patients from 10 hospitals. The primary outcome was the proportion of patients who received appropriate empirical antibiotic therapy for MRSA BSI. Appropriate therapy was defined as receipt of daptomycin, linezolid, quinupristin-dalfopristin, or vancomycin within 1 calendar day after the first blood culture result positive for S. aureus (ie, before antimicrobial susceptibilities were known). Multivariable logistic regression was used to determine variables associated with receipt of appropriate empirical therapy. The study included 562 patients with MRSA BSI. The mean (+/-standard deviation) age of the patients was 64 +/- 16 years, and 288 (51.2%) were male. Only 291 (51.8%) patients received appropriate empirical therapy. Patients were more likely to receive appropriate therapy if they required hemodialysis (odds ratio [OR], 1.36 [95% confidence interval {CI}, 1.00-1.85]), had undergone knee or hip arthroplasty (OR, 3.04 [95% CI, 1.21-7.6]), had a central venous catheter at admission (OR, 1.72 [95% CI, 1.01-2.93]), or had a McCabe score of 1 at admission (OR, 1.83 [95% CI, 1.16-2.83]). Bowel incontinence (OR, 0.41 [95% CI, 0.19-0.92]) and BSIs categorized as primary (OR, 0.41 [95% CI, 0.27-0.63]) were associated with a decreased likelihood of receiving appropriate empirical therapy. Only half of patients with MRSA BSI received appropriate empirical therapy. Factors associated with receiving appropriate empirical antibiotics included the presence of a central venous catheter at admission and a history of joint arthroplasty. Surprisingly, prior MRSA infection was not predictive of receipt of appropriate antimicrobial therapy.

Nursing Homes as Reservoirs of MRSA: Myth or Reality?

To determine the prevalence and risk factors associated with methicillin-resistant Staphylococcus aureus (MRSA) colonization among residents of a long-term care facility (LTCF) and to investigate the association of prior antibiotics use and MRSA colonization. Cross-sectional analysis. A large, 320-bed suburban long-term care facility in New York. A representative sample of 160 nursing home residents. We obtained nasal swabs to screen for MRSA colonization and reviewed the medical charts for clinical and demographic data. A total of 160 residents participated. MRSA colonization was identified in 44 residents (27.5 %). Only 5 variables were statistically significantly associated with MRSA colonization, namely race, renal insufficiency, increased use of antibiotics, prior MRSA infection during the previous year, and prior hospitalization within 3 years. Sharing a room with a MRSA carrier did not increase the risk for colonization. This study found a large reservoir of MRSA within this LTCF population. Nursing home residents with renal insufficiency, prior MRSA infection, prior hospitalization, and higher use of antibiotics were found to be at risk for MRSA colonization . These findings demonstrate that LTCFs need to be proactive in implementing appropriate antibiotics restriction practices and should give high priority to the development of more effective infection control policies.

Clinical Utility of Infection Control Documentation of Prior Methicillin-Resistant Staphylococcus aureus Colonization or Infection for Optimization of Empirical Antibiotic Therapy

This 5-year study of 25,378 hospitalizations measured the utility of infection control documentation of prior methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection for the optimization of empirical antibiotic therapy. Documented prior MRSA colonization or infection was predictive of subsequent MRSA infections (odds ratio, 4.05). Physicians appear to use this documentation when prescribing empirical therapy for suspected bacteremia.

Methicillin-resistant Staphylococcus aureus infection or colonization present at hospital admission: multivariable risk factor screening to increase efficiency of surveillance culturing.

Identifying methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection present at admission has become important in reducing subsequent nosocomial transmission, but the most efficient surveillance methods remain to be defined. We performed anterior nares surveillance cultures of all patients upon admission to and discharge from the general internal medicine floor in our community hospital over a 7-week period, and patients completed a questionnaire on MRSA risk factors. Of the 401 patients, 41 (10.2%) had MRSA upon admission. Of the 48 risk measures analyzed, 10 were significantly associated with admission MRSA, and 7 of these were independently associated in stepwise logistic regression analysis. Factor analysis identified eight latent variables that contained most of the predictive information in the 48 risk measures. Repeat logistic regression analysis including the latent variables revealed three independent risk measures for admission MRSA: a nursing home stay (relative risk [RR], 6.18; 95% confidence interval [95% CI], 3.56 to 10.72; P < 0.0001), prior MRSA infection (RR, 3.97; 95% CI, 1.94 to 8.12; P = 0.0002), and the third latent variable (factor 3; RR, 3.14; 95% CI, 1.56 to 6.31; P = 0.0013), representing the combined effects of homelessness, jail stay, promiscuity, intravenous drug use, and other drug use. Multivariable models had greater sensitivity at detecting admission MRSA than any single risk measure and allowed detection of 78% to 90% of admission MRSA from admission surveillance cultures on 46% to 58% of admissions. If confirmed in additional studies, multivariable questionnaire screening at admission might identify a subset of admissions for surveillance cultures that would more efficiently identify most admission MRSA.

Community‐onset methicillin‐resistant Staphylococcus aureus in an urban HIV clinic

To determine the proportion of skin/soft tissue infections (SSTIs) and to determine risks for MRSA infection caused by methicillin-resistant Staphylococcus aureus (MRSA) in HIV-infected out-patients. We conducted a prospective study of SSTIs in HIV-infected out-patients. A questionnaire was used to record MRSA risk factors and treatment. In vitro testing for antibiotic susceptibility, inducible clindamycin resistance, panton-valentine leucocidin (PVL) toxin, and the staphylococcal chromosomal cassette mec (SCCmec) type was performed using standardized methods. Treatment outcomes included resolution of primary site of infection, nonresolution of infection and reinfection and were confirmed at clinic visit and/or telephone follow-up. Forty-one of 44 patients had an SSTI caused by MRSA. African-Americans comprised 21 of 41 MRSA patients. The median CD4 count of MRSA patients was 411 cells/microL. Four patients required hospitalization and three patients had secondary bacteraemia. Twenty-one of 41 MRSA patients had healthcare-associated (HCA) MRSA risk factors including a history of prior MRSA infection (n=9) and hospitalization within 6 months (n=11). Other prevalent MRSA risk factors included receipt of systemic antibiotics within 6 months (n=21) and previous incarceration (n=19). Twenty-two patients had a significant non-HIV-related comorbid illness. The majority of isolates were susceptible to trimethoprim-sulfamethoxazole, tetracycline, and clindamycin. Inducible clindamycin resistance was detected in 0 of 16 erythromycin-resistant, clindamycin-susceptible MRSA isolates. Twenty-one of 24 isolates tested positive for SCCmec type IV. Twenty-four of 24 isolates tested positive for the PVL gene. Antibiotic treatment was discordant (bacteria nonsusceptible to antibiotic used) in eight MRSA patients. The primary SSTI resolved in 37 of 40 MRSA patients. Recurrence of infection at a site other than the primary site was relatively common (11 patients). We found a high rate of MRSA causing SSTI in community-dwelling patients. The majority of isolates were positive for PVL and SCCmec IV, which is typical of community-associated MRSA isolates causing SSTIs in the general population. Inducible clindamycin resistance was not detected. Most patients had MRSA risk factors. The initial site of infection resolved in most cases but subsequent MRSA infection was relatively common.

Percutaneous Endoscopic Gastrostomy Sites Infected by Methicillin-resistant Staphylococcus aureus: Impact on Outcome

The impact of methicillin-resistant Staphylococcus aureus (MRSA) colonization of percutaneous endoscopic gastrostomy (PEG) sites on morbidity and mortality is uncertain. We investigated the impact of known prior MRSA colonization on the incidence of symptomatic PEG site wound infection and mortality. Consecutive patients who had PEG tubes inserted recently at our hospital were identified. The presence or absence of MRSA colonization before PEG placement was noted. Patients were observed for wound infection, and swabs were taken from the site if there was clinical infection. Mortality within 30 days of PEG placement was determined. A total of 83 patients underwent PEG placement; 23 (28%) of these patients had known MRSA colonization before PEG placement. Of these, 13 (57%) developed symptomatic MRSA infection of the PEG site. The remaining 60 patients (72%) had no known prior MRSA colonization. In these patients, 9 (15%) developed symptomatic MRSA infection of the PEG site. The overall incidence of wound infection was 37% (31) of the total undergoing PEG placement, of whom 71% (22) had developed MRSA infection. The mortality of those with symptomatic MRSA infection of the PEG site was 9% (2/22), whereas the mortality from non-MRSA-infected PEGs was 20% (12/61). Patients with prior MRSA colonization had a significantly higher risk of developing symptomatic MRSA infection of the PEG site. However, there was still a significant risk (15%) of developing MRSA infection of the PEG site for patients with no known prior MRSA infection. MRSA infection of the PEG site did not affect mortality.

Methicillin-Resistant Staphylococcus aureus Infections in Vascular Surgery: Increasing Prevalence

Methicillin-resistant Staphylococcus aureus (MRSA) is a virulent organism that causes substantial infection-related morbidity and mortality in hospitalized patients. For example, MRSA infection of prosthetic vascular grafts can be limb- and life-threatening in surgical patients. We investigated the incidence of MRSA infection in vascular surgical patients who developed postoperative infectious complications. Prospective data (including procedure, nature of complication, and outcome) were collected on all vascular surgery patients (n = 772) over a two-year period from January, 2000, to December, 2001. The study cohort included all patients who developed postoperative complications (n = 119, 15.4%), including infection, unplanned or prolonged intubation, metabolic abnormalities, and myocardial ischemia. Bacteriologic data of all clinical cultures were reviewed and infection-related outcomes were examined. Hospital-acquired infection occurred in 79 (66.4%) of 119 patients who developed postoperative complications. Review of microbiology data (total, 197 bacterial isolates) confirmed that gram-positive organisms were the leading cause of infections, with 120 gram-positive isolates (60.9%). Of the gram-positive isolates, S. aureus was the most common pathogen, isolated in 73 (60.8%) cultures. The single most prevalent organism was MRSA, identified in 42 of 73 (57.5%) of cultures. The site of MRSA infection was confirmed to be the surgical site (54.8%), sputum (17.0%), blood (14.3%), urine (9.5%), peritoneal fluid (2.4%), or catheter insertion site (2.4%). Only four patients had prior MRSA infection or colonization. Prosthetic vascular grafts were placed in 51 (42.9%) of the 119 vascular patients, and 26 patients (51.6%) acquired MRSA infection. Graft removal was required in three patients due to infection (MRSA infection in two patients, Pseudomonas aeruginosa in one patient). Forty percent of patients with MRSA infection required an amputation as their surgical procedure. No patient died of MRSA bacteremia during the study period. Mean hospital length of stay (LOS) was longer in patients with MRSA infection (29.6 d vs. 22.7 days, range 2-174 days, p < 0.05) compared to the total study cohort of vascular patients with postoperative infections. Methicillin-resistant S. aureus has emerged as the leading cause of postoperative infection in vascular surgery patients, and is associated with substantial morbidity, increased hospital LOS, and higher incidences of amputation and graft removal. Greater emphasis on preoperative screening protocols for MRSA colonization is warranted, in conjunction with aggressive infection control measures, alteration of preoperative prophylactic antimicrobial use in MRSA-colonized patients, and meticulous postoperative surveillance for MRSA infection. Furthermore, antimicrobial treatment of postoperative infectious complications in vascular surgery patients should include empiric coverage for MRSA in institutions where MRSA is endemic.

Staphylococcus aureus carrier state among elderly residents of a long-term care facility.

Methicillin-resistant Staphylococcus aureus (MRSA) infections have recently become a major concern in long-term care facilities (LTCF). Patients that have been colonized with MRSA in general hospitals may introduce the organisms into LTCF, and these can become reservoirs for the pathogen. Our objective was to evaluate the rate of colonization by S aureus, especially MRSA, in elderly residents of a large LTCF, and to find factors that predispose to it. A nasal culture was obtained from randomly selected patients in an Israeli LTCF. Inclusion criteria were absence of active infection and no antibiotic treatment in the preceding month. The carrier state was defined when two consecutive cultures were positive for S aureus. The study population comprised 270 patients, aged 81 +/- 9.3 years and from all types of wards. Of these, 63 (23.3%) were carriers of S aureus and 17 of those (27%) had MRSA. From univariate analysis, the carrier state was associated with antibiotic treatment or an invasive procedure in the previous 3 months, and with a prior MRSA infection. Subacute LTCF departments had a higher carrier rate than the chronic care wards. In this large multilevel facility, 6.2% of the patients were MRSA carriers, and came predominantly from the subacute departments, suggesting an influx from general hospitals. This information and the identification of factors associated with MRSA infection permit the development of an institutional infection control program.