Methicillin-resistant Staphylococcus aureus (MRSA) is a pandemic human pathogen accounting for most of health-care associated infections throughout the world. However, in recent years, a more virulent strain of MRSA has emerged in the community defined as community-associated MRSA (CA-MRSA). These emerging strains of CA-MRSA are described to have different antibiotic susceptibility profiles, possess the SCCmec type IV element and usually produce the Panton-Valentine leukocidin (PVL) toxin. The majority of these CA-MRSA strains are associated with skin and soft tissue infections and necrotising pneumonia, with a 34% mortality rate. Identification and characterisation of MRSA isolates is mainly performed using phenotypic methods, which are time consuming. Little information exists on the prevalence and characteristics of MRSA isolates including antibiotic susceptibility patterns, PVL-producing CAMRSA strains, the SCCmec types and genotypes that might be circulating in the Steve Biko Academic Hospital. Identification and characterisation of MRSA isolates based on these criteria are important in controlling possible outbreaks in the clinical setting. In this study, 97 clinical MRSA isolates from the Steve Biko Academic Hospital, South Africa were collected between April 2006 to February 2007. These isolates were analysed and characterised using multiplex PCR (M-PCR), real-time PCR as well as staphylococcal protein A (spa) and hyper-variable region (HVR) typing. The aim of this study was to determine the antibiotic profiles, prevalence of MRSA isolates, the SCCmec types and the genotypes. Antibiotic susceptibility determination was performed using the disk diffusion susceptibility method as guidelined by the CLSI. Six distinct antibiotypes were identified with a total of 73%, 71%, 70% and 7% of MRSA isolates resistant to clindamycin, erythromycin, gentamicin and fusidic acid, respectively. The presence of Staphylococcus aureus specific 16S rRNA, the mecA and PVL genes was determined using a modified M-PCR assay. A total of 4% of the MRSA isolates possessed the PVL gene. Real-time PCR analysis also showed a 100% prevalence of the PVL gene in the same 4% MRSA isolates confirming the results of the first M-PCR assay. The second M-PCR was used to determine the SCCmec type prevalence and to distinguish between health-care associated MRSA (HA-MRSA) and CA-MRSA. SCCmec typing showed 67% of the isolates belonged to SCCmec type II and 14.4% SCCmec type III, both types belonging to HA-MRSA. A total of 4% of the MRSA isolates were CA-MRSA belonging to SCCmec type IVd. Genotyping results showed three distinct spa clusters whilst HVR showed six distinct clusters. Molecular-based assays proved to be useful tools to determine the prevalence and monitoring of MRSA outbreaks as well as to identify the SCCmec types, subtypes and genotypes of MRSA strains that might be circulating in the hospital. The determination of the different antibiotypes of MRSA can assist in the monitoring of the antibiotic resistant profile trends in the Steve Biko Academic Hospital, thus assisting with the correct implementation of antibiotic regimens for suspected MRSA infections. In an endeavour to assess the dissemination of MRSA strains especially PVL expressing CA-MRSA strains, it is of paramount importance to continuously monitor the emergence of these strains in clinical settings. Copyright / Dissertation (MSc)--University of Pretoria, 2010. / Medical Microbiology / unrestricted

BACKGROUND: The risk factors, microbial etiology, differentiation, and clinical features of purulent and non-purulent cellulitis are not well defined in Taiwan. METHODS: We conducted a retrospective cohort study of hospitalized adults with cellulitis in Taiwan in 2013. The demographic characteristics, underlying diseases, clinical manifestations, laboratory and microbiological findings, treatments, and outcomes were compared for patients with purulent and non-purulent cellulitis. RESULTS: Of the 465 patients, 369 had non-purulent cellulitis and 96 had purulent cellulitis. The non-purulent group was significantly older (p = 0.001) and was more likely to have lower limb involvement (p < 0.001), tinea pedis (p = 0.003), stasis dermatitis (p = 0.025), a higher Charlson comorbidity score (p = 0.03), and recurrence at 6 months post-infection (p = 0.001) than the purulent group. The purulent group was more likely to have a wound (p < 0.001) and a longer hospital stay (p = 0.001) and duration of antimicrobial therapy (p = 0.003) than the non-purulent group. The etiological agent was identified in 35.5 % of the non-purulent cases, with β-hemolytic streptococci the most frequent cause (70.2 %). The etiological agent was identified in 83.3 % of the purulent cases, with Staphylococcus aureus the predominant pathogen (60 %): 50 % of these were methicillin-resistant S. aureus (MRSA). In multivariable analysis, purulent group (odds ratio (OR), 5.188; 95 % confidence interval (CI), 1.995-13.493; p = 0.001) was a positive predictor of MRSA. The prescribed antimicrobial agents were significantly different between the purulent and non-purulent groups, with penicillin the most frequently used antimicrobial agent in the non-purulent group (35.2 %), and oxacillin the most frequent in the purulent group (39.6 %). The appropriate antimicrobial agent was more frequently prescribed in the non-purulent group than in the purulent group (83.2 % vs. 53.8 %, p < 0.001). CONCLUSIONS: The epidemiology, clinical features, and microbiology of purulent and non-purulent cellulitis were significantly different in hospitalized Taiwanese adults. Purulence was a positive predictor of MRSA as the causal agent of cellulitis. These findings provide added support for the adoption of the IDSA guidelines for empirical antimicrobial therapy of cellulitis in Taiwan.

Our investigation sought to identify the incidence of treatment failure and its associated costs in patients with methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections (SSTIs) treated in the primary care setting. Thirteen clinics participated in this multi-site, observational study. Clinicians consented patients and collected clinical information, pictures, and wound swabs; isolates were processed in the principal investigator's laboratory. Treatment failure was defined as the occurrence of one or more of the following within 90 days: (1) change in antibiotic therapy, (2) subsequent need for incision and drainage, (3) SSTI at new site, (4) SSTI at same site, (5) emergency department visit, or (6) hospitalization. Cost estimates were obtained from the Agency for Healthcare Research and Quality (AHRQ) and Centers for Medicare and Medicaid Service's National Average Drug Acquisition Costs (NADAC). Patients were considered to have “moderate or complicated” SSTIs if they had a lesion ≥ 5cm in diameter, diabetes mellitus, or both. Patients not exhibiting these characteristics were classified as having “mild or uncomplicated” infections. Ninety-eight patients were enrolled. Most patients were of Hispanic ethnicity and more than half of all patients had a body mass index (BMI) ≥ 30kg/m2. The most common treatment modality was incision and drainage (I&D) plus antibiotics (57%). Treatment failure occurred in 21% of all patients at a mean additional cost of $1,933.71. Patients with moderate or complicated SSTIs who received I&D experienced significantly more treatment failures compared mild or uncomplicated patients who received I&D (36% vs. 10%; p = 0.04). The additional cost of treatment failure in patients with moderate or complicated SSTIs was nearly twice that of patients with mild or uncomplicated SSTIs ($2,093.40 vs. $1,255.02; p = 1.0). Treatment failure occurred sooner, on average, in the moderate or complicated group compared to the mild or uncomplicated group (11.8 days vs. 38.8 days; p = 0.06). Among patients with MRSA SSTIs treated in the primary care setting, the rate of treatment failure is high (21%) and costs are considerable ($1,933.71). / text

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2009. / Härtill 5 uppsatser.

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious public health problem nationwide, threatening to develop into an epidemic. Many of these patients are presenting to their primary care clinics with skin and soft tissue infections (SSTIs). The CDC has reported that in 2005, MRSA was responsible for an estimated 94,000 life-threatening infections and 16,650 deaths. The purpose of this study is to estimate the incidence of CA-MRSA within a specific family practice in Florida and to identify epidemiologic factors, classify antibiotic susceptibility patterns, and evaluate patient education in regard to disease management and prevention. This study was a descriptive, epidemiologic, three-year retrospective medical record review of all wound cultured skin and soft tissue infections that presented to a family practice between January 2007 and December 2009. Sixty-two medical records met the inclusion and exclusion criteria for the study. Of these 62 SSTIs, 44 cultures grew one or more bacterial organisms. The incidence of CA-MRSA was 66% (n=29). The mean age of those with CA-MRSA was 40 years old, with a range from 7 to 90 years old. Sixty-two percent (n=18) were male and 38% (n=11) were female; additionally 69% (n=20) lived within a 10 mile radius from the family practice, while 31% (n=9) lived in a surrounding suburb. The most frequent race was Caucasian 83% (n=24), with African American at 10% (n=3) and Hispanics 7% (n=2). Risk factors associated with CA-MRSA was obesity 41% (n=10), diabetes mellitus 24% (n=7), and a previous history of MRSA infection 24% (n=7). Skin and soft tissue infections were diagnosed as either an abscess 62% (n=18), boil 24% (n=7), pustule 10% (n=3), or cellulitis 4% (n=1). CA-MRSA isolates were susceptible to trimethoprim-sulfamethoxazole 100% (n=29), doxycycline 93% (n=27), and rifampin 100% (n=14). Clindamycin susceptibility was 65% (n=15) with resistance at 30% (n=7) and 5% (n=1) intermediate. Both cephalexin and erythromycin were 100% resistant. Documentation in the medical record on wound care was found in 45% (n=13) of the records. The incidence of CA-MRSA SSTI was 66%, which identifies this suburban community at high risk for this bacterial infection. Risk factors associated with CA-MRSA included obesity (BMI > 30), history of previous MRSA infection, and diabetes mellitus. There were no clinical characteristics that helped distinguish MRSA infection from other bacterial SSTIs. Most SSTI were treated with incision and drainage and a susceptible antibiotic. Judicious use of antibiotics not only provides appropriate treatment, but is also critical in prevention of antibiotic resistance. Lastly, patient education in adequate hygiene is essential in preventing the spread of CA-MRSA

The purpose of this thesis was to quantify the prevalence, measure the severity, and describe treatment patterns in patients who present to medical clinics in Texas with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) skin and soft-tissue infections (SSTI). Ten clinics participated in this prospective, community-based study. Clinicians consented patients and collected clinical information, pictures, and wound swabs; data were processed centrally. MRSASelect[trademark] was used for identification. Susceptibilities were determined via Etest[registered sign]. The results are as follows. Overall, 73/119 (61%) patients had CA-MRSA. Among these, 49% were male, 79% were Hispanic, and 30% had diabetes. Half (56%) of the lesions were [greater than or equal to] 5 cm in diameter. Most patients had abscesses (82%) and many reported pain scores of [greater than or equal to] 7/10 (67%). Many presented with erythema (85%) or drainage (56%). Most received incision and drainage (I&D) plus an antibiotic (64%). Antibiotic monotherapy was frequently prescribed: sulfamethoxazole/ trimethoprim (SMX/TMP) (78%), clindamycin (4%), doxycycline (2%), and mupirocin (2%). The rest frequently received SMX/TMP in combination with other antibiotics. SMX/TMP was commonly administered as one double-strength tablet twice daily. Isolates were 93% susceptible to clindamycin and 100% susceptible to vancomycin, doxycycline, SMX/TMP, and linezolid. We report a predominance of CA-MRSA SSTIs, favorable susceptibilites, and frequent prescribing of SMX/TMP in primary care clinics located in South Texas. / text

Blastomycosis is an endemic systemic fungal infection that usually involves the lungs and superficial skin. Although head and neck involvement has been reported in the literature, no previous cases of neck mass resulting from direct extension of a pulmonary lesion have been published. We encountered an immunocompetent 31-year-old woman with a rapidly enlarging subcutaneous neck mass and a chronic upper lung infiltrate. Imaging studies showed contiguity between both lesions. Blastomyces dermatitidis was recovered from the sputum, and typical yeast was observed in fungal stains of needle aspirate from the neck mass. The patient responded favorably to a 6-month course of itraconazole. Blastomycosis should be considered in patients with subcutaneous neck masses in areas where this disease is endemic.