Lack of methicillin-resistant Staphylococcus aureus nasal carriage among patients at a primary-healthcare unit in Porto Alegre, Brazil

INTRODUCTION: Community-associated methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a pathogen in individuals without traditional risk factors. MATERIAL AND METHODS: MRSA nasal carriage was assessed in individuals consulting at a Primary Health Unit in Brazil. RESULTS: A total of 336 individuals were included: 136 were tested only for MRSA and 200 for any S. aureus. No MRSA was found among the 336 individuals and 23 (11.5%) of 200 were colonized by S. aureus. DISCUSSION: Low prevalence rates have been found in non-hospitalized individuals, but MRSA surveillance should be encouraged to monitor clinical and molecular epidemiology of CA- MRSA.

Comparison of five methods for oxacillin susceptibility testing of Staphylococcus aureus isolates from cystic fibrosis patients

Methicillin-resistant Staphylococcus aureus (MRSA) are now a worldwide problem. Cystic fibrosis (CF) patients are commonly colonized and infected by MRSA. Accurate oxacillin susceptibility testing is mandatory for the adequate management of these patients. We performed a comparison of the accuracy of different tests in CF isolates, including methicillin-susceptible S. aureus and MRSA with different SCCmec types, and using the mecA gene as the gold-standard. The sensitivity and specificity of oxacillin disc, Etest, and oxacillin agar screening plate were 100%. Sensitivity of the cefoxitin disc was 85% and specificity was 100%. For clinically relevant isolates, laboratories may consider the use of a combination of two phenotypic methods.

Community-Associated Methicillin-Resistant Staphylococcus Aureus Lacking PVL, as a Cause of Severe Invasive Infection Treated with Linezolid

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging public health problem worldwide. Severe invasive infections have been described, mostly associated with the presence of Panton-Valentine leukocidin (PVL). In Portugal limited information exists regarding CA-MRSA infections. In this study we describe the case of a previously healthy 12-year-old female, sport athlete, who presented to the hospital with acetabulofemoral septic arthritis, myositis, fasciitis, acetabulum osteomyelitis, and pneumonia.The MRSA isolated from blood and synovial fluid was PVL negative and staphylococcal enterotoxin type P (SEP) and type L (SEL) positive, with a vancomycin MIC of 1.0mg/L and resistant to clindamycin and ciprofloxacin. The patient was submitted to multiple surgical drainages and started on vancomycin, rifampicin, and gentamycin. Due to persistence of fever and no microbiological clearance, linezolid was started with improvement. This is one of the few reported cases of severe invasive infection caused by CA-MRSA in Portugal,which was successfully treated with linezolid. In spite of the severity of infection, the MRSA isolate did not produce PVL.

In vitro SCREENING ANTIBACTERIAL ACTIVITY OF Bidens pilosa LINNÉ AND Annona crassiflora MART. AGAINST OXACILLIN RESISTANT Staphylococcus aureus (ORSA) FROM THE AERIAL ENVIRONMENT AT THE DENTAL CLINIC

Currently multiresistant Staphylococcus aureus is one common cause of infections with high rates of morbidity and mortality worldwide, which directs scientific endeavors in search for novel antimicrobials. In this study, nine extracts from Bidens pilosa (root, stem, flower and leaves) and Annona crassiflora (rind fruit, stem, leaves, seed and pulp) were obtained with ethanol: water (7:3, v/v) and their in vitro antibacterial activity evaluated through both the agar diffusion and broth microdilution methods against 60 Oxacillin Resistant S. aureus (ORSA) strains and against S. aureus ATCC6538. The extracts from B. pilosa and A. crassiflora inhibited the growth of the ORSA isolates in both methods. Leaves of B. pilosa presented mean of the inhibition zone diameters significantly higher than chlorexidine 0.12% against ORSA, and the extracts were more active against S. aureus ATCC (p < 0.05). Parallel, toxicity testing by using MTT method and phytochemical screening were assessed, and three extracts (B. pilosa, root and leaf, and A. crassiflora, seed) did not evidence toxicity. On the other hand, the cytotoxic concentrations (CC50 and CC90) for other extracts ranged from 2.06 to 10.77 mg/mL. The presence of variable alkaloids, flavonoids, tannins and saponins was observed, even though there was a total absence of anthraquinones. Thus, the extracts from the leaves of B. pilosa revealed good anti-ORSA activity and did not exhibit toxicity.

On the track of β-lactam resistance: Studies on the regulation of methicillinresistance in Staphylococcus aureus

Dissertação para obtenção do Grau de Doutor em Biologia

Insights into cell wall synthesis and cell division in Staphylococcus aureus

Dissertation presented to obtain the Ph.D degree in Biology

BRAIN ABSCESS DUE TO Staphylococcus aureus OF CRYPTOGENIC SOURCE IN AN HIV-1 INFECTED PATIENT IN USE OF ANTIRETROVIRAL THERAPY

The spectrum of neurological complications associated with human immunodeficiency virus type 1 (HIV-1) infection is broad. The most frequent etiologies include primary diseases (caused by HIV itself) or secondary diseases (opportunistic infections or neoplasms). Despite these conditions, HIV-infected patients are susceptible to other infections observed in patients without HIV infection. Here we report a rare case of a brain abscess caused by Staphylococcus aureus in an HIV-infected patient. After drainage of the abscess and treatment with oxacilin, the patient had a favorable outcome. This case reinforces the importance of a timely neurosurgical procedure that supported adequate management of an unusual cause of expansive brain lesions in HIV-1 infected patients.

Endemic Methicillin-Resistant Staphylococcus Aureus: Nurses' Risk Perceptions and Attitudes

Dissemination of methicillin-resistant Staphylococcus aureus (MRSA) remains one of the most difficult challenges for prevention, control, and treatment of health care-associated infections. A survey and interviews were conducted on nurses from a hospital center. We found that most nurses' perceived risk of acquiring MRSA related to themselves (72%), other nurses (88.5%), and patients (97.8%). This perception influences attitudes, leading to compliance with the existing recommendations.

Cell division and chromosome segregation in Staphylococcus aureus

Dissertação para a obtenção do grau de doutor em Biologia pelo Instituto de Tecnologia Química e Biológica. Universidade Nova de Lisboa

Peptidoglycan assembly machines: The Staphylococcus aureus Penicillin-Binding Proteins

Dissertation presented to obtain the Ph.D degree in Biology

Estudo longitudinal sobre portador são de Staphylococcus aureus em alunos de um curso de auxiliar de enfermagem

Este trabalho objetivou conhecer o grau de colonização pelo Staphylococcus aureus e a evolução do estado de portador são em alunos de um curso de Auxiliar de Enfermagem, durante a formação profissional. Participaram 42 alunos, dos quais foram colhidas amostras da cavidade nasal e mãos (direita e esquerda) em seis diferentes momentos da formação. Do total de alunos, 19 (45,2%) comportaram-se como portadores ocasionais, 12 (28,6%) como intermitentes, 6 (14,3%) como persistentes e 5 (11,9%) como não portadores, demonstrando que a colonização não aumentou com o decorrer do curso. Dos alunos, 24 (57,1%) referiram não terem desenvolvido atividades relacionadas à enfermagem antes e/ou durante o curso e 18 (42,9%) referiram exercê-las como atendentes.

O papel de determinantes plasmídicos na resistência a compostos antimicrobianos em Staphylococcus aureus

Dissertação para obtenção do Grau de Mestre em Microbiologia médica

Regulation and function of the cell wall polymer lipoteichoic acid in staphylococcus aureus

A thesis submitted for the Degree of Master in Medical microbiology

Avaliação da presença de Staphylococcus aureus nos leitos do Centro de Terapia Intensiva do Hospital Escola da Faculdade de Medicina do Triângulo Mineiro, em relação à posição no colchão antes e após a limpeza

Através de meios de cultura, foi pesquisada a posição de colônias de Staphylococcus aureus em colchões, visando avaliar a eficácia do procedimento de limpeza e desinfecção dos leitos do Hospital Escola da Faculdade de Medicina do Triângulo Mineiro (Uberaba). Foram analisadas amostras de 50 colchões no período de 22 de outubro de 2000 a 16 de janeiro de 2001. As amostras foram coletadas e semeadas, pela técnica de esgotamento, em dois meios de cultivo (ágar sangue e manitol) com posterior realização de provas de catalase e coagulase . Na análise estatística, foram utilizados os testes não paramétricos Mann-Whitney, Kruswkal- Wallis e Wilcoxon Matched Pairs Test com nível de significância p < 0,05. Foram utilizadas 600 placas de meio de cultivo. Houve crescimento em 94 (15,6%), sendo 82 (87,2%) antes e 12 (12,8%) após a limpeza e desinfecção. Em relação à posição no leito, as amostras semeadas no meio de cultivo com manitol mostraram que não houve redução significativa na posição inferior do leito (p>0,05). Os resultados apontam e alertam para falhas no procedimento de limpeza e desinfecção dos leitos hospitalares por nós estudados.

Preliminary study of community-acquired Staphylococcus aureus infection in Manaus Hospital, Amazonia Region, Brazil

Methicillin resistant Staphylococcus aureus is considered a public health problem with a strong potential for dissemination and high rates of morbidity and mortality. In this study we describe bacteriological and epidemiological characteristics of Staphylococcus aureus in Manaus (Amazon region). During the one-year study period (2000-2001), sixteen cases of acute pyogenic multiple abscess were evaluated. Community-acquired S. aureus was identified as causative agent in 10 (62.5%) patients. The strains tested with antimicrobials by discs diffusion method, exhibited a high rate of sensitivity to cephalexin (100%), erythromycin (90%). Oxacillin-susceptible Staphylococcus aureus was 90%. No isolate was resistant to Vancomycin. To our knowledge, no series of community-acquired Staphylococcus aureus in Manaus hospital has been published. Our partial results showed a high rate of antimicrobial sensitivity among community-acquired Staphylococcus aureus in the hospital of Tropical Medicine Institute of Manaus, Amazon Region.