High Methicillin-resistant Staphylococcus Aureus Incidence Research Articles

Intraosseous Regional Administration of Vancomycin Prophylaxis for Primary and Revision Total Knee Arthroplasty.

The advantages of prophylaxis with intraosseous regional administration (IORA) of vancomycin for periprosthetic joint infection (PJI) in primary and revision total knee arthroplasty (TKA) include the ability to deliver antibiotics directly to the surgical bed and avert systemic delivery; the ability to precisely time and quickly administer vancomycin to achieve the highest concentrations at the beginning and throughout the surgical procedure; and the ability to avert several common and potentially serious adverse effects of intravenous vancomycin. Indications for IORA of vancomycin prophylaxis include the following clinical scenarios: revision TKA; obesity; diabetes; beta-lactam allergy; known colonization with methicillin-resistant Staphylococcus aureus (MRSA); individuals coming from institutions with a high MRSA incidence; previous ligamentous surgical procedure or osteotomy; current or recent smokers; in the primary TKA setting if the individual is considered high-risk as defined by the criteria above; and during reimplantation following 2-stage exchange for PJI.

Primarily treated patients versus referred patients in the treatment of native septic arthritis of digits: a retrospective comparative study

BackgroundSeptic arthritis of digits needs urgent treatment. When treatments delayed or insufficient, patients may be referred to the upper-level hospital due to uncontrolled infection. We reviewed the treatment history of referred patients and compared the microorganisms and the clinical course of both primary and referred patients as relevant studies are rare.MethodsIn this retrospective review of consecutive case series, 45 patients (primary, n = 11; referred, n = 34) were treated with multiple irrigation and debridement. Cefazolin was used as empiric antibiotics, then changed according to microbiologic study. Previously used antibiotics, treatment delay, surgical history of the referred patients were reviewed. Identified microorganisms, required surgical intervention, hospital stay, radiologic outcome, functional outcomes were compared between both groups.ResultsIn the referred patients, methicillin-resistant Staphylococcus aureus (MRSA) was commonly found and cefazolin was susceptible in only 15% of the cases. Longer hospital stay, prolonged antibiotic therapy, more surgical intervention including flap surgery was required to treat the referred patients. Postoperative pain was not severe in daily activities, but the final range of motion was significantly less in the referred patients compared to the primary patients.ConclusionsThis study suggests that in the treatment of uncontrolled septic arthritis of the digits, antibiotic agents covering MRSA may shorten the duration of antibiotic therapy in areas of high MRSA incidence. Besides, more number of I & D including flap surgery may be required for the referred patients compared with the primary patients. These findings can help the surgeon in setting up a treatment plan or in counseling of referred patients with uncontrolled septic arthritis of the digits.

High Incidence of Oxacillin-Susceptible mecA-Positive Staphylococcus aureus (OS-MRSA) Associated with Bovine Mastitis in China

Staphylococcus aureus is a main cause of bovine mastitis and a major pathogen affecting human health. The emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) has become a significant concern for both animal health and public health. This study investigated the incidence of MRSA in milk samples collected from dairy cows with clinical mastitis and characterized the MRSA isolates using antimicrobial susceptibility tests and genetic typing methods. In total, 103 S. aureus isolates were obtained from dairy farms in 4 different provinces in China, including Gansu, Shanghai, Sichuan, and Guizhou. Antimicrobial susceptibility testing of these isolates revealed that the resistance rates to penicillin and sulfamethoxazole were high, while the resistance rates to ciprofloxacin and vancomycin were low. Among the 103 isolates, 49 (47.6%) were found to be mecA-positive, indicating the high incidence of MRSA. However, 37 of the 49 mecA-positive isolates were susceptible to oxacillin as determined by antimicrobial susceptibility assays and were thus classified as oxacillin-susceptible mecA-positive S. aureus (OS-MRSA). These isolates could be misclassified as methicillin susceptible Staphylococcus aureus (MSSA) if genetic detection of mecA was not performed. Molecular characterization of selected mecA-positive isolates showed that they were all negative with Panton-Valentine leukocidin (PVL), but belonged to different spa types and SCCmec types. These results indicate that OS-MRSA is common in bovine mastitis in China and underscore the need for genetic methods (in addition to phenotypic tests) to accurately identify MRSA.

Characterization of Methicillin Resistant Staphylococcus aureus from various clinical samples at tertiary care hospital of rural Gujarat

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is an established pathogen in most health care facilities. MRSA strains are also important for their resistance to many other commonly used antibiotics. Objectives: To find out prevalence of MRSA strains and coproduction of β-lactamase and antibiotic sensitivity pattern of these strains. Materials and Methods: During the period of September 2009 to December 2010, a total of 200 strains of S. aureus were isolated from various specimens of different patients attending and admitted at C. U. Shah Medical College and Hospital, Surendranagar, Gujarat. Standard procedures were followed for isolation and identification of S. aureus isolates. Antibiotic susceptibility testing and detection of MRSA was done by Kirby Bauer disk diffusion method, as per Clinical and Laboratory Standards Institute (CLSI) guidelines. The production of β-lactamase was studied by the rapid method using nitrocefin disk. Results: Among 200 isolates of S. aureus, 117 (58.5 %) were methicillin-resistant, of which 110 (94.02%) were found to be multidrug-resistant. Among 117 MRSA strains, 86.59 % were resistant to ciprofloxacin, 81.71% were resistant to cephalexin, 80.49% were resistant to cefaclor and 79.27% were resistant to erythromycin. Vancomycin was the most effective drug as all MRSA isolates were sensitive to it. 93.90% MRSA isolates were sensitive to linezolid and 91.46% were sensitive to teicoplanin. 82.91% MRSA isolates were also co-producers of β-lactamase. Conclusions: The high incidence of MRSA in this hospital warrants for the judicial use of antibiotics and application of infection control measures to avoid therapeutic crisis resulting from multidrug-resistant MRSA. Key Words: MRSA, Staph aureus, Rural Gujarat

What is the Rate of Methicillin-resistant Staphylococcus aureus and Gram-negative Infections in Open Fractures?

There have been increasing reports of methicillin-resistant Staphylococcus aureus (MRSA) infections in the community, but it is unclear whether infectious organisms in open fracture infections have changed and if our current regimen of antibiotic prophylaxis is therefore obsolete. We determined the recent incidence of MRSA and Gram-negative organism infections after open fractures. We performed a retrospective cohort study on 189 patients with 202 open fractures treated from 2009 to 2010. During the followup, patients were evaluated for signs of infection using the Centers for Disease Control and Prevention criteria. We determined the organisms using routine microbiology culture. The minimum followup was 3months (median, 47months; range, 3-108months). Of the 202 open fractures, 20 (10%) developed infections. The most common organism was Staphylococcus, whereas five (25%) of those infected were positive for MRSA, and 11 (55%) of those with infection were cultured for at least one Gram-negative organism. Six (30%) open fractures had infections that grew out multiple organisms. The incidence of MRSA infections in our open fracture population was 2.5%. There is a high incidence of MRSA and Gram-negative infections after open fractures, which may indicate that current antibiotic regimens need to be changed. Level IV, retrospective case-series. See the Guidelines for Authors for a complete description of levels of evidence.

MRSA colonisation in patients with proximal femur fractures in a German trauma centre: incidence, infection rates and outcomes

The aim of this study was to assess the incidence of methicillin-resistant Staphylococcus aureus (MRSA) colonisation in patients admitted into a level 1 German trauma centre with proximal femur fractures, to correlate this incidence with defined risk factors for MRSA colonisation and to determine its influence on morbidity and mortality. Between August and November 2006, 65 patients were included in the study. Cotton-tipped swab samples were taken from the nose, throat, groin and any skin defects in the emergency room. The following factors were recorded: age, gender, any concomitant diseases, the fracture type and treatment device, skin lesions, hospitalisation within the last year, any urinary or vascular catheters, a nasogastric or gastrostomy tube, an ileal stoma, the use of a respirator and antibiotic therapy within the last year. During follow-up, data concerning any surgical site infections; any chest, urinary or vascular catheter infections; the success of decontamination and death within 1year after surgery were collected. The risk factors for MRSA colonisation were positive in 40 patients. The incidence of MRSA colonisation was 17%, which is higher than in most comparable studies but consistent with some very recent publications. The nosocomial infection rates, surgical site infection rates and mortality within the 1-year follow-up period were significantly higher in the MRSA-colonised patients. The high incidence of MRSA in this study supports the need for systematic detection of MRSA-colonised patients. In our hospital, any patient with positive risk factors for MRSA colonisation is swabbed in the emergency room and treated as MRSA positive until proven otherwise.

Typing of methicillin-resistant Staphylococcus aureus in a university hospital setting by using novel software for spa repeat determination and database management.

The spa gene of Staphylococcus aureus encodes protein A and is used for typing of methicillin-resistant Staphylococcus aureus (MRSA). We used sequence typing of the spa gene repeat region to study the epidemiology of MRSA at a German university hospital. One hundred seven and 84 strains were studied during two periods of 10 and 4 months, respectively. Repeats and spa types were determined by Ridom StaphType, a novel software tool allowing rapid repeat determination, data management and retrieval, and Internet-based assignment of new spa types following automatic quality control of DNA sequence chromatograms. Isolates representative of the most abundant spa types were subjected to multilocus sequence typing and pulsed-field gel electrophoresis. One of two predominant spa types was replaced by a clonally related variant in the second study period. Ten unique spa types, which were equally distributed in both study periods, were recovered. The data show a rapid dynamics of clone circulation in a university hospital setting. spa typing was valuable for tracking of epidemic isolates. The data show that disproval of epidemiologically suggested transmissions of MRSA is one of the main objectives of spa typing in departments with a high incidence of MRSA.

Prevalence of methicillin-resistant Staphylococcus aureus carriage at the time of admission in two acute geriatric wards

Studies on methicillin-resistant Staphylococcus aureus (MRSA) in the elderly have been concerned with patients hospitalized in nursing homes or long-term care facilities. Our objective was to estimate the prevalence of MRSA at the time of admission in two acute geriatric wards with high endemic MRSA incidence in a French teaching hospital. A prospective screening of MRSA carriers was conducted by swabbing nares and wounds during five weeks for all patients on the day of admission. For each patient demographic, administrative, clinical and therapeutic data were recorded. Their associations with MRSA carriage were studied by logistic regression analysis. On the day of admission, 35 patients (14.6%) were MRSA carriers. Variables independently associated with carriage were hospitalization within the six last months (OR = 4.64; P < 0.001) and the existence of wounds or bedsores (OR = 2.864; P = 0.02). The high prevalence of MRSA carriage at the time of admission could explain in part the high incidence of MRSA in these wards. A systematic selective screening targeted on patients with high risk of carriage should be helpful to implement barrier precautions and reduce cross-transmission.

Predominance of a methicillin-resistant Staphylococcus aureus clone susceptible to erythromycin and several other non-beta-lactam antibiotics in a Greek hospital.

A clone of heterogeneously methicillin-resistant Staphylococcus aureus (MRSA) isolates susceptible to erythromycin, ciprofloxacin, clindamycin, co-trimoxazole, nitrofurantoin, rifampicin, tetracycline and vancomycin, predominated in a Greek hospital with a high incidence of MRSA, representing 69.1% of the total MRSA isolates. All isolates of this clone lacked the conserved genes ermA and aadD. Two subtypes of this clone were detected, the more common being resistant to aminoglycosides and carrying the bi-functional gene aacA-aphD, while an aminoglycoside-susceptible variant, lacking this gene, lost a larger SmaI macrorestriction DNA fragment and gained a smaller fragment.