EVALUATION OF METHODS IN DETECTING VANCOMYCIN MIC AMONG MRSA ISOLATES AND THE CHANGES IN ACCURACY RELATED TO DIFFERENT MIC VALUES

INTRODUCTION: Methicillin-Resistant Staphylococcus aureus (MRSA) presenting reduced susceptibility to vancomycin has been associated to therapeutic failure. Some methods used by clinical laboratories may not be sufficiently accurate to detect this phenotype, compromising results and the outcome of the patient. OBJECTIVES: To evaluate the performance of methods in the detection of vancomycin MIC values among clinical isolates of MRSA. MATERIAL AND METHODS: The Vancomycin Minimal Inhibitory Concentration was determined for 75 MRSA isolates from inpatients of Mãe de Deus Hospital, Porto Alegre, Brazil. The broth microdilution (BM) was used as the gold-standard technique, as well as the following methods: E-test® strips (BioMérieux), M.I.C.E® strips (Oxoid), PROBAC® commercial panel and the automated system MicroScan® (Siemens). Besides, the agar screening test was carried out with 3 µg/mL of vancomycin. RESULTS: All isolates presented MIC ≤ 2 µg/mL for BM. E-test® had higher concordance (40%) in terms of global agreement with the gold standard, and there was not statistical difference among E-test® and broth microdilution results. PROBAC® panels presented MICs, in general, lower than the gold-standard panels (58.66% major errors), while M.I.C.E.® MICs were higher (67.99% minor errors). CONCLUSIONS: For the population of MRSA in question, E-test® presented the best performance, although with a heterogeneous accuracy, depending on MIC values.

CHEMICAL CHARACTERIZATION AND EVALUATION OF ANTIBACTERIAL, ANTIFUNGAL, ANTIMYCOBACTERIAL, AND CYTOTOXIC ACTIVITIES OF Talinum paniculatum

SUMMARY In this study, the bioactivity of Talinum paniculatum was evaluated, a plant widely used in folk medicine. The extract from the T. paniculatum leaves (LE) was obtained by percolation with ethanol-water and then subjecting it to liquid-liquid partitions, yielding hexane (HX), ethyl acetate (EtOAc), butanol (BuOH), and aqueous (Aq) fractions. Screening for antimicrobial activity of the LE and its fractions was evaluated in vitro through broth microdilution method, against thirteen pathogenic and non-pathogenic microorganisms, and the antimycobacterial activity was performed through agar diffusion assay. The cytotoxic concentrations (CC90) for LE, HX, and EtOAc were obtained on BHK-21 cells by using MTT reduction assay. The LE showed activity against Serratia marcescens and Staphylococcus aureus, with Minimum Inhibitory Concentration (MIC) values of 250 and 500 µg/mL, respectively. Furthermore, HX demonstrated outstanding activity against Micrococcus luteus and Candida albicans with a MIC of 31.2 µg/mL in both cases. The MIC for EtOAc also was 31.2 µg/mL against Escherichia coli. Conversely, BuOH and Aq were inactive against all tested microorganisms and LE proved inactive against Mycobacterium tuberculosisand Mycobacterium bovisas well. Campesterol, stigmasterol, and sitosterol were the proposed structures as main compounds present in the EF and HX/EtOAc fractions, evidenced by mass spectrometry. Therefore, LE, HX, and EtOAc from T. paniculatumshowed potential as possible sources of antimicrobial compounds, mainly HX, for presenting low toxicity on BHK-21 cells with excellent Selectivity Index (SI = CC90/MIC) of 17.72 against C. albicans.

INVESTIGATION OF BIOFILM FORMATION IN COAGULASE-NEGATIVE STAPHYLOCOCCI ISOLATED FROM PLATELET CONCENTRATE BAGS

Platelet Concentrates (PCs) are the blood components with the highest rate of bacterial contamination, and coagulase-negative staphylococci (CoNS) are the most frequently isolated contaminants. This study investigated the biofilm formation of 16 contaminated units out of 691 PCs tested by phenotypic and genotypic methods. Adhesion in Borosilicate Tube (ABT) and Congo Red Agar (CRA) tests were used to assess the presence of biofilm. The presence of icaADC genes was assessed by means of the Polymerase Chain Reaction (PCR) technique. With Vitek(r)2, Staphylococcus haemolyticus was considered the most prevalent CoNS (31.25%). The CRA characterized 43.8% as probable biofilm producers, and for the ABT test, 37.5%. The icaADC genes were identified in seven samples by the PCR. The ABT technique showed 85.7% sensitivity and 100% specificity when compared to the reference method (PCR), and presented strong agreement (k = 0.8). This study shows that species identified as PCs contaminants are considered inhabitants of the normal skin flora and they might become important pathogens. The results also lead to the recommendation of ABT use in laboratory routine for detecting biofilm in CoNS contaminants of PCs.

Experiências terapêuticas com a alfa-6-deoxi-5-oxitetraciclina (doxiclina): um nôvo antibiótico de largo espectro

A Doxiciclina, um nôvo antibiótico derivado da oxitetraciclina, foi administrada a 54 pacientes, 16 com diversas entidades infecciosas, 18 portadores de Staphylococcus aureus e 20 portadores de Streptococcus beta haemolyticus. O medicamento, que foi empregado em dose única diária, por via oral, durante períodos variáveis de acôrdo com a entidade clínica e com a evolução do caso, mostrou-se de excelente tolerância e de grande eficiência, particularmente nas infecções por Staphylococcus aureus e Streptococcus beta haemolyticus que representam a maior incidência desta casuística.

Infecção hospitalar num berçário de alto risco: análise de dois anos

Um estudo prospectivo sobre infecção hospitalar foi realizado por dois anos, no período de agosto de 1987 a julho de 1989 no berçário de alto risco do Hospital de Clínicas da Universidade Federal do Paraná. Foram identificadas as taxas mensais de infecção hospitalar com os agentes e a localização da infecção. A taxa média de infecção foi de 30%. Staphylococcus aureus/o; o agente etiológico mais comum. A infecção mais freqüente foi a cutâneo-mucosa. Medidas educativas foram o fator mais importante na redução das taxas.

Bacteriological evaluation of wounds in seriously burned hospitalized patients

During the period between May and December 1988, 21 patients were studied bacteriologically at Hospital João XXIII's burn's unit which belongs to "Fundação Hospitalar do Estado de Minas Gerais" in Belo Horizonte, Brazil. A qualitative and quantitative evaluation of aerobic and facultative bacteria from burn wounds was carried out by the standard filter paper disc technique, including antibiotic susceptibility. At the same time an evaluation of those bacteria isolated from the environmental unit was performed. The most common organisms recovered from wounds of patients were: Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. P. pseudomallei was the most frequent strain recovered from environmental specimens. In nearly all patients specimens (16 in total) from whom P. aeruginosa was isolated, the rate of CFU/cm² of skin was above 10². In nine of these, it reached 10(5), wich is equivalent to 10(7) CFU/g of burned tissue.

A associação entre a toxocaríase humana e os abscessos piogênicos

A associação entre o abscesso hepático e a esquistosomose mansônica foi confirmada por estudos clínicos e experimentais. Outros parasitos, como a larva de Toxocara canis, podem causar alterações imunológicas sistêmicas e estruturais nos órgãos acometidos que favorecem a instalação e o crescimento da bactéria. A piomiosite tropical, o abscesso hepático piogênico e o abscesso renal são doenças freqüentes nos países tropicais e muitas vezes não se encontra doença de base que poderia explicá-las. A síndrome de larva migrans visceral é causada pela presença no organismo humano de larvas de vermes que têm outros animais como hospedeiro definitivo sendo a T. canis o agente mais comum. As larvas migram por vários órgãos causando reação inflamatória na forma de granuloma com necrose tecidual. Nesta revisão discutem-se os possíveis mecanismos de interação entre o hospedeiro, o parasito e a bactéria que podem favorecer a formação de abscessos nos órgãos acometidos pela larva de T. canis e resumem-se alguns resultados preliminares de trabalho clínico-experimental realizado durante os últimos quatro anos para definir o papel deste parasito na patogenia dos abscessos.

Prevalência da microbiota no trato digestivo de fêmeas de Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae) provenientes do campo

No presente trabalho foram dissecados o trato digestivo de 245 fêmeas de Lutzomyia longipalpis originários da Gruta da Lapinha, Município de Lagoa Santa, MG, formando 7 grupos de 35 flebotomíneos. Das 8 espécies de bactérias isoladas houve uma predominância de bactérias Gram negativas (BGN) pertencentes ao grupo de não fermentadoras de açúcar das seguintes espécies: Acinetobacter lowffii, Stenotrophomonas maltophhilia, Pseudomonas putida e Flavimonas orizihabitans. No grupo das fermentadoras tivemos: Enterobacter cloacae e Klebsiella ozaenae. No grupo dos Gram positivos foram identificados Bacillus thuringiensis e Staphylococcus spp.

Avaliação da influência da infecção bacteriana secundária na evolução da leishmaniose cutânea em Corte de Pedra, Bahia

Foram avaliados 84 pacientes leishmanióticos com o objetivo de verificar a prevalência de infecção bacteriana secundária das úlceras cutâneas e de estudar sua relação com a cicatrização das lesões. A infecção secundária foi diagnosticada mediante cultura bacteriana aeróbica de amostra de tecido da lesão. Todos os pacientes receberam tratamento antimonial durante 20 dias e fizeram lavagem da úlcera com água e sabão comum. A casuística foi composta principalmente de adolescentes e de adultos dedicados à lavoura, apresentando lesão única. Em 47,6%, as úlceras estudadas estavam localizadas nas pernas e nos pés. Verificou-se infecção secundária em 45/83 (54,2%), sendo mais freqüente nas lesões localizadas abaixo dos joelhos. O Staphylococcus aureus predominou (88,9%). A reepitelização completa das úlceras, avaliada em 79 pacientes um mês após o fim do tratamento, não foi influenciada pela infecção secundária.

Pesquisa de bactérias do gênero Vibrio em feridas cutâneas de pescadores do município de Raposa-MA

O estudo foi realizado com o objetivo de isolar e identificar bactérias do gênero Vibrio em feridas cutâneas apresentando processo infeccioso, em pescadores do município de Raposa-MA. O material clínico foi obtido com o emprego de "swab" e mantido em meio de transporte de Cary-Blair. Para o processamento laboratorial foram utilizadas técnicas clássicas de enriquecimento em água peptonada alcalina, isolamento em meio seletivo-indicador (TCBS) e identificação bioquímica das espécies. Participaram do estudo 50 pescadores, com idade variando de 12 a 65 anos, tendo sido reconhecidos 21 indivíduos portadores de Vibrio. Houve predomínio da espécie V. alginolyticus (66,6%), seguido de V. parahaemolyticus (42,8%) e de V. cholerae não O1 (9,5%). As lesões predominaram nos membros inferiores, apresentando hiperemia, edema, secreção, dor. Associados aos vibrios foram isoladas espécies de bacilos gram negativos dos gêneros Serratia, Proteus, Escherichia, Citrobacter, Enterobacter, assim como outras bactérias não-fermentadoras (30,9%) e bactérias gram positivas do gênero Staphylococcus.

Sepsis in burned patients

A prospective study was conducted from June 2001 to May 2002 at the Burns Unit of Hospital Regional da Asa Norte, Brasília, Brazil. During the period of the study, 252 patients were treated at the Burns Unit, 49 (19.4%) developed clinically and microbiologically proven sepsis. Twenty-six (53.1%) were males and 23 (46.9%) females with a mean age of 22 years (range one to 89 years) and mean burned body surface area of 37.7 ± 18.4% (range 7 to 84%). Forty-three patients had flame burns, five a scald and one an electric burn. These 49 patients had a total of 62 septic episodes. Forty (81.6%) patients had only one and nine (18.4%) had up to three episodes of sepsis. Thirty (61.2%) patients had their first septicemic episode either earlier or by one week postburn. Out of 62 septic episodes, 58 were due to bacteria and four due to Candida sp. The most common bacteria isolated from blood culture were Staphylococcus aureus, coagulase-negative Staphylococcus, Acinetobacter baumannii, Enterobacter cloacae and Klebsiella pneumoniae. Eleven (18.9%) episodes were due to oxacillin resistant Staphylococcus aureus. Acinetobacter baumannii was sensitive to ampicillin/sulbactam in 71.4% and to imipenem in 85.7% of the cases. The primary foci of sepsis were the burn wound in 15 ( 24.2% ) episodes. The most common clinical findings of sepsis in these patients were fever, dyspnea, hypotension and oliguria. The most common laboratory findings of these patients were anemia, leukocytosis, hypoalbuminemia and thrombocytopenia. Twelve (24.5%) patients died. The appropriate knowledge of clinical, epidemiological, laboratorial and microbiological aspects of sepsis in burned patients permits an adequate diagnosis and treatment of this complication.