Risk Factors For Methicillin-resistant Research Articles

Staphylococcus aureus nasal colonization among health care workers at an Egyptian tertiary care hospital

Background: Staphylococcus aureus (S. aureus) colonization in health care workers (HCWs) is a major factor of nosocomial infections. Methicillin resistant S. aureus (MRSA) is incriminated in hospital-acquired infection. Objectives: To evaluate the colonization rates of nasal carriage of S. aureus and MRSA among HCWs at Al-Ahrar Teaching Hospital. Methods: We recruited 163 HCWs in a cross section study. S. aureus was identified phenotypically by coagulase, with DNase tests and genotypically by nuc gene detection. Antibiotics sensitivity was tested by disk diffusion. PCR for mecA was done to confirm MRSA identification. Results: Forty-eight S. aureus strain were isolated. The frequency of nasal colonization of S. aureus in HCWs was 29.44% (48/163), the frequency of MRSA isolates in HCWs was 27.6% (45/163), and frequency of MRSA isolates among S.aureus isolates was 93.8% (45/48). Prior infection (last 3 months) and living in crowded places increased significantly risk of MRSA nasal carriage by 29.3 and 79.59 folds respectively Conclusion: We demonstrated high rates of nasal carriage of S. aureus and MRSA among HCWs. Prior infection and living in crowded places were risk factors for methicillin resistance among isolated S.aureus stains.

Analysis on risk factors of methicillin-resistant staphylococcus aureus enterocolitis after gastrointestinal surgery

To investigate the risk factors of methicillin-resistant Staphylococcus aureus(MRSA) enterocolitis after gastrointestinal surgery. Clinical and pathological data of 17 cases with MRSA enteritis after gastrointestinal surgery from March 2015 to March 2017 at Department of General Surgery of Affiliated Drum Tower Hospital were retrospectively analyzed. (1) age of 18 to 80 years;(2) with history of gastrointestinal surgery; (3) diarrhea symptoms within 7 days after gastrointestinal surgery; (4) use of antibiotics before diarrhea; (5) fecal smear showing a large number of gram positive cocci; (6) fecal culture suggested the presence of MRSA; (7) application of antibiotic therapy against MRSA was effective. (1)clostridium difficile toxin positive; (2) toxic shock syndrome caused by food poisoning. According to gender, age, and inpatient ward, 1:2 pairing was performed, and 34 patients with non-MRSA enteritis from the hospitalized cases in the same ward were selected as the control group for retrospective case-control study. There were no significant differences in the gender, age, and constitution index between two groups (all P>0.05), indicating that the two groups were comparable. The χ² test was used to perform univariate analysis on 11 factors, including the nature of the primary disease, colorectal surgery, emergency surgery, use of multiple antibiotics, preoperative bowel preparation, perioperative hormone, intraoperative intraperitoneal chemotherapy, perioperative nasogastric tube, diabetes history, intensive care unit stay, and previous infectious disease hospitalization, and then multivariate logistic regression analysis was performed. MRSA enteritis occurred 3 to 5 days after surgery in all the 17 cases, and 4 cases developed septic shock rapidly. Univariate analysis showed that the operation site (colorectal surgery) (χ²=4.747, P=0.029) and use of two antibiotics before MRSA enteritis (χ²=3.959, P=0.047) were associated with MRSA enteritis after gastrointestinal surgery. Multivariate logistic regression analysis revealed that colorectal surgery was the only independent risk factor for MRSA enteritis after gastrointestinal surgery(OR=5.526, 95%CI: 1.350-22.602,P=0.017), while the use of two antibiotics was not (OR=0.204, 95%CI:0.051-0.819, P=0.025). MRSA enteritis has a rapid onset, and a high incidence of septic shock, which requires immediate attention. Colorectal surgery is an independent risk factor for MRSA enteritis.

A Risk-Scoring System for Predicting Methicillin Resistance in Community-Onset Staphylococcus aureus Bacteremia in Korea.

We aimed to develop a simple scoring system to predict risk for methicillin resistance in community-onset Staphylococcus aureus bacteremia (CO-SAB) by identifying the clinical and epidemiological risk factors for community-onset methicillin-resistant S. aureus (MRSA). We retrospectively analyzed data from three multicenter cohort studies in Korea in which patient information was prospectively collected and risk factors for methicillin resistance in CO-SAB were identified. We then developed and validated a risk-scoring system. To analyze the 1,802 cases of CO-SAB, we included the four most powerful predictors of methicillin resistance that we identified in the scoring system: underlying hematologic disease (-1 point), endovascular infection as the primary site of infection (-1 point), history of hospitalization or surgery in ≤1 year (+0.5 points), and previous isolation of MRSA in ≤6 months (+1.5 points). With this scoring system, cases were classified into low (less than -0.5), intermediate (-0.5-1.5), and high (≥1.5) risk groups. The proportions of MRSA cases in each group were 24.7% (22/89), 39.0% (607/1,557), and 78.8% (123/156), respectively, and 16.7% (1/6), 33.8% (112/331), and 76.9% (10/13) in a validation set. This risk-scoring system for methicillin resistance in CO-SAB may help physicians select appropriate empirical antibiotics more quickly.

Staphylococcus aureus urinary tract bacteriuria: single-institutional antibiotic susceptibility trends over a decade

Objectives: Methicillin resistant Staphylococcus aureus (MRSA) is a troublesome pathogen which is difficult for clinicians to treat. The purpose of this surveillance program is to assess the prevalence of MRSA urinary tract infections and determine risk factors for methicillin resistance in adults amongst urinary isolates of SA and to describe the antibiotic susceptibilities to guide empirical therapy.Methods: From 2005 through to 2014, we retrospectively reviewed urine cultures recorded in a laboratory database at a university hospital in Cambridge, UK. Susceptibility testing was performed by BSAC (British Society of Antimicrobial Chemotherapy) disc diffusion testing and reported for fluoroquinolones, gentamicin, nitrofurantoin, linezolid, trimethoprim and vancomycin. Samples were denoted “MRSA” if they were resistant to oxacillin or cefoxitin.Results: In total, 690 cultures were positive for SA, of which 293 (42.5%) were methicillin resistant. The number of SA bacteriuria decreased from around 100 per year to 40 per year. The proportion demonstrating methicillin resistance decreased from around 60% to around 20%. Both methicillin-sensitive Staphylococcus aureus (MSSA) and MRSA isolates were susceptible to vancomycin and nitrofurantoin. MRSA isolates demonstrated some increased resistance to trimethoprim and gentamicin and greatly increased resistance to fluoroquinolones. Urinary catheterization and increasing age were risk factors for methicillin resistance.Conclusion: The incidence of SA and MRSA bacteriuria decreased during the study period. A high degree of resistance to fluoroquinolones was observed in MRSA compared to MSSA. Analysis of antibiotic susceptibility profiles suggests nitrofurantoin and trimethoprim may be useful in treating uncomplicated MSSA and MRSA urinary tract infections without concurrent bacteremia.

Impacto de la resistencia a la meticilina sobre la mortalidad y vigilancia de la sensibilidad a la vancomicina en bacteriemias causadas por Staphylococcus aureus

Staphylococcus aureus is a major nosocomial pathogen that causes severe morbidity and mortality in many hospitals worldwide. Besides, the incidence of S. aureus bacteremia has significantly increased over the past decades. The aims of this study were to detect the risk factors for methicillin resistance and mortality and to evaluate vancomycin susceptibility in methicillin-resistant isolates. Thus, 39 S. aureus isolates from blood cultures of hospitalized patients with bacteremia were studied in Nueva Clínica Chacabuco Tandil, Buenos Aires, Argentina during 01/2006-12/2008. The overall mortality was 51.3%, which was significantly associated with methicillin resistance (OR: 4.20, IC95%: 1.08-16.32, p: 0.05), even though it was not an independent mortality predictor as it was the mechanical ventilation (OR: 15.99, IC95%: 3.24 - 78.86). Previous surgery (OR: 17.23, IC95%: 1.80-164.60) and hospitalization in intensive care units (OR: 21.12, IC95%: 2.33-191.30) were independent predictors of meticillin-resistance. No isolates were found with reduced vancomycin susceptibility. All the studied isolates were in vitro susceptible to vancomycin with a MIC50 and MIC90 of 0.5 μg/ml.

Analysis of Methicillin Resistance among Staphylococcus aureus Blood Isolates in an Emergency Department

The increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) has become of great concern in both hospital and community settings. To evaluate the prevalence and risk factors for methicillin resistance among Staphylococcus aureus, blood isolates in our Emergency Department (ED) were collected. All patients with S. aureus bacteremia (SAB) who presented to the ED from January 2000 to August 2005 were included, and a retrospective study was performed. A total of 231 patients with SAB were enrolled (median age, 59 yr; M:F, 125:106). Among these patients, methicillin-resistant strains accounted for 27.3% (63 patients). Catheter-related infection was the most frequent primary site of SAB (39.0%), followed by skin and soft tissue infection (16.5%). In multivariate analysis, recent surgery (OR, 3.41; 95% CI, 1.48-7.85), recent hospitalization (2.17; 1.06-4.62), and older age (≥61 yr) (2.39; 1.25-4.57) were independently associated with the acquisition of methicillin-resistant strains. When antimicrobial therapy is considered for the treatment of a patient with suspected SAB, clinicians should consider obtaining cultures and modifying empirical therapy to provide MRSA coverage for patients with risk factors: older age, recent hospitalization, and recent surgery.

Risk Factors for Methicillin-Resistance among Patients with Staphylococcus aureus Bacteremia at the Time of Hospital Admission

Community-acquired infections caused by methicillin-resistant Staphylococcus aureus (MRSA) seem to be increasing. Characteristics permitting recognition of patients with such strains would aid infection control efforts and choice of empiric therapy pending culture and susceptibility results. Retrospective review of medical records for all adults seen in the Emergency Care Center at Grady Memorial Hospital, Atlanta, Georgia, whose blood cultures taken within 24 hours of entry yielded S. aureus. Risk factors for the presence of methicillin resistance in S. aureus isolates recovered from patients with staphylococcal bacteremia were assessed. S. aureus isolates from 118 (40%) of 297 study patients with bacteremia at the time of admission were methicillin-resistant. Multivariate analysis identified hospitalization in the 6 months preceding admission [odds ratio (OR) = 4.4; 95% CI, 2.0-9.8], receipt of antimicrobial agents in the past 3 months (OR = 5.6; 95% CI, 2.6-11.9], presence of indwelling urinary catheter (OR = 7.3; CI, 2.5-20.9), and nursing home residence (OR = 9.9; 95% CI, 3.9-25.6) to be independently associated with the presence of methicillin resistance. All but 4 of the 118 patients with methicillin-resistant strains had at least 1 of these factors and the proportion of resistant isolates progressively increased as more of these features were present. The presence of these risk factors should be considered when making decisions about isolation and other infection control procedures as well as empiric antimicrobial therapy with vancomycin for patients with suspected staphylococcal infection at the time of hospital admission. Similar studies could guide practices for dealing with such patients in other centers, because the occurrence of MRSA infections at the time of admission may vary widely by geographic area.