Preoperative risk factors for nasal carriage of Staphylococcus aureus.

BACKGROUND: Staphylococcus aureus nasal carriage is a risk factor for surgical-site infections (SSIs) caused by S. aureus, and eradication of carriage reduces postoperative nosocomial infections caused by it. No study has compared large groups of preoperative carriers and non-carriers to identify factors that are linked to S. aureus nasal carriage. METHODS: While conducting a clinical trial evaluating whether mupirocin prevented S. aureus SSIs, we prospectively collected data on 70 patient characteristics that might be associated with S. aureus carriage. We performed stepwise logistic regression analysis. RESULTS: Of the 4,030 patients, 891 (22%) carried S. aureus. Independent risk factors for S. aureus nasal carriage were obesity (odds ratio [OR], 1.29; 95% confidence interval [CI95], 1.11-1.50), male gender (OR, 1.29; CI95, 1.11-1.51), and a history of a cerebrovascular accident (OR, 1.53; CI95, 1.03-2.25) for all patients. Factors associated with nasal carriage varied somewhat by surgical specialty. In all groups, preoperative use of antimicrobial agents was independently associated with a lower risk of carrying S. aureus in the nares. Previously identified risk factors were not significantly associated with S. aureus nasal carriage in this large group of surgical patients. CONCLUSION: Male gender, obesity, and a history of a cerebrovascular accident were identified as risk factors for S. aureus nasal carriage. It remains to be seen whether preoperative weight loss would reduce the rate of nasal carriage. In addition, the value of screening this patient population for S. aureus nasal carriage merits further investigation.     

Nasal carriage of S. aureus increases the risk of surgical site infection after major heart surgery

Staphylococcus aureus is the main cause of surgical site infection (SSI) after major heart surgery (MHS), with the patient's endogenous flora as the principal source. However, the influence of nasal carriage of S. aureus on the development of SSI after MHS has not been established and Centers for Disease Control and Prevention guidelines do not make a recommendation for or against decolonisation. We performed a one-year observational study in which patients undergoing MHS were screened for nasal carriage of S. aureus before surgery. Cases of SSI were recorded and the risk factors of patients with and without SSI were analysed. During the study period, 357 patients were included in the protocol. Ninety-six patients (27%) were found to be nasal carriers of S. aureus and nine (9.4%) of these had meticillin-resistant (MRSA) strains. The overall incidence of SSI was 6.4%, with 4.2% for mediastinitis and 2.2% for superficial SSI. Nasal carriers of S. aureus had a significantly higher incidence of SSI than non-carriers (12.5% vs 5%, P=0.01). Among MRSA carriers, the incidence of SSI reached 33% (P<0.001). S. aureus was responsible for 64% of SSIs. Multivariate analysis showed that the independent factors for SSI were S. aureus nasal carriage [relative risk (RR): 3.1; 95% confidence interval (CI): 1.4-7.3; P=0.009], reoperation (RR: 3.1; 95% CI: 1.8-19.2; P=0.04) and diabetes mellitus (RR: 5.9; 95% CI: 1.8-19.2; P=0.003). Nasal carriage of S. aureus significantly increases the rate of nosocomial SSI after MHS and decolonisation strategies should be implemented in this population.     

Nasal carriage of Staphylococcus aureus among patients receiving allergen-injection immunotherapy: associated factors and quantitative nasal cultures.

OBJECTIVE: To compare the prevalence of nasal Staphylococcus aureus carriage among outpatients receiving allergen-injection immunotherapy with the prevalence among healthy controls and to determine predictors of nasal S. aureus carriage. DESIGN: Survey. SETTING: Allergy clinic of a university hospital. PARTICIPANTS: A volunteer sample consisting of 45 outpatients undergoing desensitization therapy and 84 first- and second-year medical students. RESULTS: The nasal S. aureus carriage rate was significantly higher among patients (46.7%) than among students (26.2%; P=.019). In a multivariate model adjusted for age and gender, the presence of atopic dermatitis or eczema was the only independent predictor of nasal S. aureus carriage (odds ratio [OR], 4.4; 95% confidence interval [CI95], 1.2-16.0; P=.02). The only other participant characteristic associated with nasal S. aureus carriage was immunotherapy with allergen injections (OR, 1.98; CI95, 0.7-6.0), but this association did not reach statistical significance (P=.23). The probability of nasal S. aureus carriage was 88.9% for patients receiving allergen injections and having atopic dermatitis or eczema, and 36.1% for patients receiving allergen injections without atopic dermatitis or eczema. CONCLUSIONS: Patients undergoing desensitization have a higher nasal carriage rate of S. aureus. However, factors other than the regular use of needles, and in particular abnormalities related to the atopic constitution of these patients, may predispose this population for S. aureus carriage.     

Nose picking and nasal carriage of Staphylococcus aureus.

OBJECTIVE: Nasal carriage of Staphylococcus aureus is an important risk factor for S. aureus infection and a reservoir for methicillin-resistant S. aureus. We investigated whether nose picking was among the determinants of S. aureus nasal carriage. SETTING AND PARTICIPANTS: The study cohort comprised 238 patients who visited the ear, nose, and throat (ENT) disease outpatient clinic of a tertiary care hospital and did not have a nose-specific complaint (defined as ENT patients) and 86 healthy hospital employees (including medical students and laboratory personnel). MEASUREMENTS: All participants completed a questionnaire on behavior regarding the nose and were screened for S. aureus nasal carriage; only ENT patients underwent nasal examination by an ear, nose, and throat physician for clinical signs of nose picking. RESULTS: Among ENT patients, nose pickers were significantly more likely than non-nose pickers to carry S. aureus (37 [53.6%] of 69 vs 60 [35.5%] of 169 patients; relative risk, 1.51 [95% confidence interval, 1.03-2.19]). Among healthy volunteers, there was a statistically significant positive correlation between the self-perceived frequency of nose picking and both the frequency of positive culture results (R=0.31; P=.004) and the load of S. aureus present in the nose (R=0.32; P=.003). CONCLUSION: Nose picking is associated with S. aureus nasal carriage. The role of nose picking in nasal carriage may well be causal in certain cases. Overcoming the habit of nose picking may aid S. aureus decolonization strategies.     

Staphylococcus aureus rectal carriage and its association with infections in patients in a surgical intensive care unit and a liver transplant unit.

BACKGROUND: The role of rectal carriage of Staphylococcus aureus as a risk factor for nosocomial S. aureus infections in critically ill patients has not been fully discerned. METHODS: Nasal and rectal swabs for S. aureus were obtained on admission and weekly thereafter until discharge or death from 204 consecutive patients admitted to the surgical intensive care unit and liver transplant unit RESULTS: Overall, 49.5% (101 of 204) of the patients never harbored S. aureus, 21.6% (44 of 204) were nasal carriers only, 3.4% (7 of 204) were rectal carriers only, and 25.5% (52 of 204) were both nasal and rectal carriers. Infections due to S. aureus developed in 15.7% (32 of 204) of the patients; these included 3% (3 of 101) of the non-carriers, 18.2% (8 of 44) of the nasal carriers only, 0% (0 of 7) of the rectal carriers only, and 40.4% (21 of 52) of the patients who were both nasal and rectal carriers (P - .001). Patients with both rectal and nasal carriage were significantly more likely to develop S. aureus infection than were those with nasal carriage only (odds ratio, 3.9; 95% confidence interval, 1.18 to 7.85; P= .025). By pulsed-field gel electrophoresis, the infecting rectal and nasal isolates were clonally identical in 82% (14 of 17) of the patients with S. aureus infections. CONCLUSIONS: Rectal carriage represents an underappreciated reservoir for S. aureus in patients in the intensive care unit and liver transplant recipients. Rectal plus nasal carriage may portend a greater risk for S. aureus infections in these patients than currently realized.     

Comparison of routine prophylaxis with vancomycin or cefazolin for femoral neck fracture surgery: microbiological and clinical outcomes.

OBJECTIVE: To assess the impact of antibiotic prophylaxis on the emergence of vancomycin-resistant strains of Enterococcus faecium, Enterococcus faecalis, and Staphylococcus aureus and the incidence of surgical site infection (SSI) after vancomycin or cefazolin prophylaxis for femoral neck fracture surgery. DESIGN: Prospective cohort study. SETTING: A hospital with a high prevalence of methicillin-resistant S. aureus (MRSA) carriage. PATIENTS: All patients admitted with a femoral neck fracture from March 1, 2004 through February 28, 2005 were prospectively identified and screened for MRSA and vancomycin-resistant (VRE) carriage at admission and at day 7. Deep incisional and organ/space SSIs were also recorded. RESULTS: Of 263 patients included in the study, 152 (58%) received cefazolin and 106 (40%) received vancomycin. At admission, the prevalence of MRSA carriage was 6.8%; it was 12% among patients with risk factors and 2.2% among patients with no risk factors (P=.002). At day 7 after surgery, there were 6 patients (2%) who had hospital-acquired MRSA, corresponding to 0.7% in the cefazolin group and 5% in the vancomycin group (P=.04); none of the MRSA isolates were resistant to glycopeptides. The rate of VRE carriage at admission was 0.4%. Three patients (1%) had acquired carriage of VRE (1 had E. faecium and 2 had E. faecalis); all 3 were in the cefazolin group (2% of patients) and none in the vancomycin group (P=.27). Eight SSIs (3%) occurred, 4% in the cefazolin group and 2% in the vancomycin group (P=.47). CONCLUSIONS: This preliminary study demonstrates that cefazolin and vancomycin prophylaxis have similar impacts on the emergence of glycopeptide-resistant pathogens. Neither MRSA infection nor increased rates of SSI with other bacteria were observed in the vancomycin group, suggesting that a larger multicenter study should be initiated.     

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

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

幼儿园儿童携带金黄色葡萄球菌及其影响因素分析

目的 了解幼儿园儿童金黄色葡萄球菌(金葡菌)的携带状况及其影响因素.方法本研究采用多阶段分层整群抽样方法,抽取柳州市六所幼儿园的1 702名健康儿童,进行鼻拭子采样并分离鉴定金葡菌.各组金葡菌携带率的比较采用x2检验,金葡菌携带影响因素的多因素分析采用Logistic回归分析模型.结果 儿童鼻腔金葡菌携带率为16.27...     

A bundle of care to reduce colorectal surgical infections: an Australian experience

Staphylococcus aureus carriage increases the risk of infection. Demographic and microbiological data from adult patients with nasal S. aureus carriage were analysed in order to define effect modifiers of this association. Predictors for growth of S. aureus from clinical cultures were identified in a case-control study using bivariate and multi-variate logistic regression analysis. Between 1 January 2005 and 1 April 2009, 645 patients with nasal S. aureus colonization and documented follow-up of ≥90 days were identified; 159 (25%) patients were found to carry meticillin-resistant S.?aureus (MRSA). The median age of patients was 58 years, and 421 (65%) were male. During the subsequent 90 days, one or more clinical cultures were positive for S. aureus in 131 patients (20%). Multi-variate analysis identified a prior history of any S. aureus positive culture [adjusted odds ratio (aOR) 2.4, 95% confidence interval (CI) 1.5-3.8; P=0.0005) as an independent predictor of subsequent S. aureus infection. MRSA colonization was a predictor of infection in patients aged >40 years (aOR 2.5, 95% CI 1.4-4.1; P=0.0004), and even more so in patients aged ≤40 years (aOR 12.4, 95% CI 3.0-51; P=0.0005). Age >40 years was an additional independent risk?factor for meticillin-susceptible S. aureus carriers (aOR 3.0, 95% CI 1.2-7.8; P=0.02) but not for MRSA carriers. Preferential screening of patients at high risk for MRSA carriage and subsequent infection, as well as the absence of a universal policy for the use of decolonization regimens, may partly explain the relatively high risk of S. aureus infection in the patient population. MRSA carriers and older patients with recurrent S. aureus positive cultures may gain the greatest benefit from routine decolonization measures.     

Risk factors for surgical site infection complicating laminectomy.

OBJECTIVE: To examine risk factors for surgical site infection (SSI) following spinal surgery and to analyze the associations between a surgeon's years of operating experience and surgical specialty and patients' SSI risk. DESIGN: Case-control study. SETTING: A tertiary care facility and a community hospital in Durham, North Carolina. PATIENTS: Each case patient who developed an SSI complicating laminectomy was matched with 2 noninfected control patients by hospital, year of surgery, and National Nosocomial Infection Surveillance System risk index score. RESULTS: Forty-one case patients with SSI complicating laminectomy and 82 matched control patients were analyzed. Nonwhite race, diabetes and an elevated body mass index (BMI) were more common among case patients than among control patients. Subjects with a BMI greater than 35 were more likely to undergo a prolonged procedure, compared with case patients who had a BMI of 35 or less. The SSI rate for patients operated on by neurosurgeons was 28%, compared with 43% for patients operated on by orthopedic surgeons (odds ratio [OR], 0.5; P=.12). The number of years of operating experience were not associated with SSI risk. Multivariate analysis revealed diabetes (OR, 4.2 [95% confidence interval {CI}, 1.1-16.3]; P=.04), BMI greater than 35 (OR, 7.1 [95% CI, 1.8-28.3]; P=.005), and laminectomy at a level other than cervical (OR, 6.7 [95% CI, 1.4-33.3]; P=.02) as independent risk factors for SSI following laminectomy. CONCLUSION: Diabetes, obesity, and laminectomy at a level other than cervical are independent risk factors for SSI following laminectomy. Preoperative weight loss and tight perioperative control of blood glucose levels may reduce the risk of SSI in laminectomy patients.     

柳州市幼儿园儿童金黄色葡萄球菌携带聚集性分析

  目的  探讨柳州市幼儿园儿童金黄色葡萄球菌(金葡菌)携带的聚集性及影响因素,为预防和控制金葡菌在学校儿童中的传播提供重要依据。  方法  2018年4—6月,对柳州市分层整群抽取的1 702名幼儿园儿童进行双侧鼻拭子采样,对其家长进行问卷调查,采用随机效应Logistic回归分析金葡菌携带的聚集性及影响因素。  结果  儿童金葡菌携带率为16.3%(277/1 702)。随机效应Logistic回归分析表明,金葡菌携带在班级水平的随机效应具有统计学意义(Z=2.12,P<0.01),提示具有班级聚集性;影响因素分析提示,6~7岁(OR=2.18,95%CI=1.45~3.27)和5岁(OR=1.65,95%CI=1.08~2.50)儿童金葡菌携带率高于3~4岁儿童,近1年有抗生素服用史(OR=1.45,95%CI=1.05~2.01)和近1年有皮肤软组织感染史(OR=1.36,95%CI=1.04~1.79)与儿童金葡菌携带均呈正相关(P值均<0.05)。  结论  幼儿园儿童金葡菌携带存在明显的班级聚集性,年龄、抗生素服用史和皮肤软组织感染是影响儿童金葡菌携带的重要影响因素。     

Carriage of Staphylococcus aureus among injection drug users: lower prevalence in an injection heroin maintenance program than in an oral methadone program.

OBJECTIVES: To compare the prevalence of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) carriage among injection drug users (IDUs) treated in an injection heroin maintenance program with that among IDUs treated in an oral methadone program, and to determine predictors of S. aureus carriage. DESIGN: Survey. SETTING: Two opiate maintenance programs at a psychiatric university clinic. PARTICIPANTS: A volunteer sample consisting of 94 (74%) of 127 IDUs treated in an injection opiate maintenance program with at least twice daily injections of heroin, and 70 (56%) of 125 IDUs treated in an oral methadone program. RESULTS: Addicts treated in the intravenous heroin substitution program had a significantly lower overall rate of S. aureus carriage (37 of 94 [39.4%] vs 42 of 70 [60%]; P = .009) and a significantly lower rate of nasal carriage (21 of 94 [22.3%] vs 30 of 70 [42.9%]; P = .005) than did addicts treated in the oral methadone program. Being treated in the oral methadone program was the only independent predictor of S. aureus carriage (odds ratio, 2.27; 95% confidence interval, 1.19-4.31; P = .012). All S. aureus isolates were susceptible to oxacillin. CONCLUSIONS: The regular use of needles under aseptic conditions did not increase the rate of S. aureus carriage among IDUs. Further studies are necessary to investigate whether the lower rate of S. aureus carriage among IDUs treated with intravenous heroin leads to a lower incidence of S. aureus infections in these patients.     

佛山市学龄前儿童肺炎链球菌的传播模式及影响因素

目的 掌握学龄前儿童肺炎链球菌的传播模式及其影响因素,为揭示传播模式和控制传播提供重要的科学依据。方法 采用分层整群抽样法,抽取佛山市顺德区7所幼儿园2 031名健康儿童,进行鼻拭子采样并分离鉴定肺炎链球菌。儿童肺炎链球菌携带的聚集性分析采用随机效应模型,运用分子型别的同源性分析揭示传播模式,肺炎链球菌携带的影响因素采用χ²检验与随机效应logistic回归分析模型相结合方法。结果 儿童鼻腔肺炎链球菌携带率为21.8%。随机效应模型分析提示,儿童肺炎链球菌携带存在班级聚集性(Z=4.34,P<0.001);7所幼儿园菌株班级内同源率分别为60.9%、79.2%、76.0%、80.0%、82.8%、75.9%和33.3%;班级间同源率分别为90.6%、91.7%、88.0%、82.9%、63.8%、93.1%和76.2%。影响因素分析表明,非佛山市户籍(OR=1.36, 95%CI:1.04～1.79,P=0.027)、农村地区(OR=1.60, 95%CI:1.09～2.35,P=0.017)、鼻腔携带卡他莫拉杆菌(OR=1.91, 95%CI:1.49～2...     

Risk factors for Staphylococcus aureus nasal carriage in residents of three nursing homes in Germany

The prevalence of Staphylococcus aureus nasal carriage in three nursing homes (N=500) was 36.6%. No meticillin-resistant S. aureus (MRSA) was detected. The following significant risk factors for S. aureus nasal carriage were identified: vascular cognitive impairment [odds ratio (OR)=0.31]; diabetes mellitus (OR=1.82); hypertension (OR=0.30); chronic obstructive pulmonary disease (OR=1.86); stroke (OR=3.31); antibiotic therapy within the previous three months (OR=2.10); and level 2 care (defined as highly dependent, needing help in activities of daily living for up to 4h/day) (OR=1.97). Compared with other countries, the prevalence of MRSA nasal carriage in residents of German nursing homes is low.     

The relationship between hand hygiene practices and nasal Staphylococcus aureus carriage in healthcare workers

Background:The nasal carriage rate of Staphylococcus aureus in healthcare workers (HCWs) is higher than the general population. Their hands serve as vectors for transmitting S.aureus colonized in the nose to patients.Objectives:To determine the rate of nasal S.aureus carriage and methicillin resistance in HCWs and to evaluate the relationship between carriage and personal risk factors and hand hygiene behaviors.Methods:The questionnaire included questions about sociodemographic characteristics, occupational and personal risk factors for S.aureus carriage, the “Hand Hygiene Belief Scale (HHBS),” and “Hand Hygiene Practices Inventory (HHPI)”. Nasal culture was taken from all participants. Presence of S.aureus, methicillin and mupirocin resistance were investigated in samples.Results:The study was carried out with 269 HCWs. The prevalence of S.aureus carriage was 20.1% (n:54). Among 54 S.aureus carriers, only one person had MRSA (0.37%). All S.aureus isolates were susceptible to mupirocin. S.aureus carriage was found to be significantly lower in the smoker group (p:0.015) and in the personnel wearing gloves during the procedures of each patient (p:0.002). S.aureus culture positivity was found to decrease significantly with increasing handwashing frequency (p:0.003). The mean HHPI score was higher in women (p:0.001). The mean HHPI score was lower in the group with nasal carriers than in non-carriers (p:0.176).Conclusion:The knowledge of hand hygiene practices, high frequency of handwashing, and wearing different gloves during the procedure of each patient decrease S.aureus nasal carriage in HCWs. In addition mupirocin is still effective in nasal S.aureus carriers.Key words: Staphylococcus aureus, nasal carriage, hand hygiene practices     

Use of perioperative mupirocin to prevent methicillin-resistant Staphylococcus aureus (MRSA) orthopaedic surgical site infections

We have examined whether topical perioperative prophylaxis can reduce the incidence of methicillin-resistant Staphylococcus aureus (MRSA) surgical site infections (SSIs). Using a controlled before and after approach on patients from four orthopaedic wards, undergoing orthopaedic surgery involving insertion of metal prostheses and/or fixation, received perioperative prophylaxis with nasal mupirocin for five days, and a shower or bath with 2% (v/v) triclosan before surgery (PPNMT). After introduction of PPNMT there was a marked decrease in incidence of MRSA SSIs (per 1000 operations) from 23 in the six months beforehand (period A) to 3.3 (P<0.001) and 4 (P<0.001) in subsequent consecutive six-month periods (B and C, respectively). Of 11 MRSA SSI cases that occurred during periods B and C, only one had actually received PPNMT, and 10 occurred after acute, as opposed to elective, surgery (P<0.001). Point prevalence nasal MRSA carriage decreased from 38% before PPNMT to 23% immediately after, and 20%, 7%, 10% and 8% (P<0.001) at six-monthly intervals post-intervention. Conversely, the prevalence of nasal MRSA carriage in a control elderly medicine ward did not change significantly. Vancomycin usage, in terms of defined daily doses, declined by 23%. Low-level mupirocin resistance was found in 2.3% of S. aureus isolates from orthopaedic patients before PPNMT, and in 3.9%, 6.1%, 10% and 0% in subsequent six month periods. No S. aureus isolates with high-level mupirocin resistance were found. PPNMT can reduce the incidence of MRSA SSls after orthopaedic surgery, probably by reducing nasal MRSA carriage in the endemic setting, without selecting for mupirocin resistance.     

Nasal and hand carriage of Staphylococcus aureus in staff at a Department for Thoracic and Cardiovascular Surgery: endogenous or exogenous source?

OBJECTIVE: To investigate the rates of Staphylococcus aureus carriage on the hands and in the noses of healthcare workers (HCWs) and the relatedness of S. aureus isolates found in the two sites. DESIGN: Point-prevalence study. SETTING: Department for Thoracic and Cardiovascular Surgery at the University Hospital of Uppsala, Uppsala, Sweden. SUBJECTS AND METHODS: Samples were obtained from 133 individuals, 18 men and 115 women, using imprints of each hand on blood agar and a swab from the nose. S. aureus isolates were identified by standard methods and typed by pulsed-field gel electrophoresis. RESULTS: S. aureus was found on the hands of 16.7% of the men and 9.6% of the women, and in the noses of 33.3% of the men and 17.4% of the women. The risk ratio for S. aureus carriage on the hands with nasal carriage was 7.4 (95% confidence interval, 2.7 to 20.2; P < .001). Among the 14 HCWs carrying S. aureus on their hands, strain likeness to the nasal isolate was documented for 7 (50%). CONCLUSIONS: Half of the HCWs acquired S. aureus on the hands from patients or the environment and half did so by apparent self-inoculation from the nose. Regardless of the source of contamination, good compliance with hand hygiene is needed from all HCWs to protect patients from nosocomial infections. The moderate rate of S. aureus carriage on hands in this setting could be the result of the routine use of alcoholic hand antisepsis.     

Nasal carriage of methicillin-resistant Staphylococcus aureus in an American Indian population.

BACKGROUND AND OBJECTIVE: Although reports of methicillin-resistant Staphylococcus aureus (MRSA) infections without healthcare exposure are increasing, population-based data regarding nasal colonization are lacking. We assessed the prevalence of and risk factors for community-associated MRSA nasal carriage in patients of a rural outpatient clinic. DESIGN: A cross-sectional population survey was conducted through random sample and stratification by community of residence. Recent healthcare exposure (ie, hospitalization, dialysis, or healthcare occupation) and other risk factors for MRSA carriage were assessed. Cultures of the nares were performed. Community-associated MRSA was defined as MRSA carriage without healthcare exposure. SETTING: A predominantly American Indian community in Washington. PATIENTS: Those receiving healthcare from an Indian Health Service clinic. RESULTS: Of 1,311 individuals identified for study, 475 (36%) participated. Unsatisfactory culture specimens resulted in exclusion of 6 participants. In all, 128 (27.3%) of 469 participants had S. aureus. Nine (1.9%) of 469 had MRSA carriage; of these, 5 had community-associated MRSA (5 of 469; overall community-associated MRSA carriage rate, 1.1%). MRSA carriage was associated with antimicrobial use in the previous year (risk ratio [RR], 7.2; P = .04) and residence in a household of more than 7 individuals (RR, 4.5; P = .03). Pulsed-field gel electrophoresis indicated that 5 (55%) of 9 MRSA carriage isolates were closely related, including 3 (60%) of 5 that were community associated. CONCLUSIONS: Prevalence of community-associated MRSA colonization was approximately 1% in this rural, American Indian population. Community-associated MRSA colonization was associated with recent antimicrobial use and larger household.     

Associations between surgical site infection risk and hospital operation volume and surgeon operation volume among hospitals in the Dutch nosocomial infection surveillance network.

OBJECTIVE: To examine the association between hospital operation volume and surgeon operation volume and the risk of surgical site infection (SSI). DESIGN: Prospective, multicenter cohort study based on surveillance data. METHODS: Data were obtained from the Dutch surveillance network for nosocomial infections (Preventie Ziekenhuisinfecties door Surveillance [PREZIES]) on 9 different types of orthopedic surgery, general surgery, and gynecology procedures performed during 1996-2003. Multilevel logistic regression analysis was performed to assess the independent effect of hospital volume and surgeon volume on SSI risk. RESULTS: Hospital volume was not significantly associated with SSI risk for any of the selected procedures. Low surgeon volume was associated with an increased risk for an infection for 7 of 9 types of procedures, although this effect was statistically significant only for knee arthroplasty. For 4 procedures, the odds of exceeding the 75th percentile for duration of surgery were greater when the surgeon volume was low than when the surgeon volume was moderate or high. CONCLUSIONS: Patients operated on by surgeons with a low operation volume seem to have a higher risk of developing an SSI with some procedures, particularly knee arthroplasty. The higher SSI risk for surgeons with a low operation volume is possibly partly mediated by the longer duration of surgery, a well-known risk factor for development of SSI.     

Colonization with methicillin-resistant Staphylococcus aureus in ICU patients: morbidity, mortality, and glycopeptide use.

OBJECTIVE: To determine the impact of methicillin-resistant Staphylococcus aureus (MRSA) colonization on the occurrence of S. aureus infections (methicillin-resistant and methicillin-susceptible), the use of glycopeptides, and outcome among intensive care unit (CU) patients. DESIGN: Prospective observational cohort survey. SETTING: A medical-surgical ICU with 10 single-bed rooms in a 460-bed, tertiary-care, university-affiliated hospital. PATIENTS: A total of 1,044 ICU patients were followed for the detection of MRSA colonization from July 1, 1995, to July, 1 1998. METHODS: MRSA colonization was detected using nasal samples in all patients plus wound samples in surgical patients within 48 hours of admission or within the first 48 hours of ICU stay and weekly thereafter. MRSA infections were defined using Centers for Disease Control and Prevention standard definitions, except for ventilator-associated pneumonia and catheter-related infections, which were defined by quantitative distal culture samples. RESULTS: One thousand forty-four patients (70% medical patients) were included in the analysis. Mean age was 61+/-18 years; mean Simplified Acute Physiologic Score (SAPS) II was 36.4+/-20; and median ICU stay was 4 (range, 1-193) days. Two hundred thirty-one patients (22%) died in the ICU. Fifty-four patients (5.1%) were colonized with MRSA on admission, and 52 (4.9%) of 1,044 acquired MRSA colonization in the ICU. Thirty-five patients developed a total of 42 S. aureus infections (32 MRSA, 10 methicillin-susceptible). After factors associated with the development of an S. aureus infection were adjusted for in a multivariate Cox model (SAPS II >36: hazard ratio [HR], 1.64; P=.09; male gender: HR, 2.2; P=.05), MRSA colonization increased the risk of S. aureus infection (HR, 3.84; P=.0003). MRSA colonization did not influence ICU mortality (HR, 1.01; P=.94). Glycopeptides were used in 11.4% of the patients (119/1,044) for a median duration of 5 days. For patients with no colonization, MRSA colonization on admission, and ICU-acquired MRSA colonization, respectively, glycopeptide use per 1,000 hospital days was 37.7, 235.2, and 118.3 days. MRSA colonization per se increased by 3.3-fold the use of glycopeptides in MRSA-colonized patients, even when an MRSA infection was not demonstrated, compared to non-colonized patients. CONCLUSIONS: In our unit, MRSA colonization greatly increased the risk of S. aureus infection and of glycopeptide use in colonized and non-colonized patients, without influencing ICU mortality. MRSA colonization influenced glycopeptide use even if an MRSA infection was not demonstrated; thus, an MRSA control program is warranted to decrease vancomycin use and to limit glycopeptide resistance in gram-positive cocci.