DETECTION OF VIRULENCE GENES IN ENVIRONMENTAL STRAINS OF Vibrio cholerae FROM ESTUARIES IN NORTHEASTERN BRAZIL

The objectives of this study were to detect the presence of Vibrio cholerae in tropical estuaries (Northeastern Brazil) and to search for virulence factors in the environmental isolates. Water and sediment samples were inoculated onto a vibrio-selective medium (TCBS), and colonies with morphological resemblance to V. cholerae were isolated. The cultures were identified phenotypically using a dichotomous key based on biochemical characteristics. The total DNA extracted was amplified by PCR to detect ompW and by multiplex PCR to detect the virulence genes ctx, tcp, zot and rfbO1. The results of the phenotypic and genotypic identification were compared. Nine strains of V. cholerae were identified phenotypically, five of which were confirmed by detection of the species-specific gene ompW. The dichotomous key was efficient at differentiating environmental strains of V. cholerae. Strains of V. cholerae were found in all four estuaries, but none possessed virulence genes.

USE OF MUELLER-HINTON BROTH AND AGAR IN THE GERM TUBE TEST

Candida albicans is often isolated from clinical samples, thus its presumptive differentiation from other species of the same genus can be based on its ability to form the germ tube in human serum. Nevertheless, there are two other species that share this characteristic: C. dubliniensis and C. africana. The aim of this study was to compare four different substrates to perform the germ tube (GT) test. The Candida spp. isolates were identified using a manual system (135 C. albicans, 24 C. tropicalis and one C. dubliniensis). The germ tube test was performed with fresh, previously frozen serum and Mueller-Hinton (MH) broth and agar. GT was observed in 96% (130/136) of the isolates through the fresh serum technique, 94% (128/136) through previously frozen serum, 92% (125/136) in MH agar, and 90% (122/136) in MH broth. The sensitivity of each test was higher than 90%, with 100% specificity. Both the MH agar and broth were able to identify the true positives, and false positives were not found. However, some C. albicans isolates were not identified. MH agar and broth may be used in laboratory for the rapid presumptive identification of C. albicans, as an alternative method for germ tube test.

ANTIFUNGAL ACTIVITY OF SILVER NANOPARTICLES OBTAINED BY GREEN SYNTHESIS

Silver nanoparticles (AgNPs) are metal structures at the nanoscale. AgNPs have exhibited antimicrobial activities against fungi and bacteria; however synthesis of AgNPs can generate toxic waste during the reaction process. Accordingly, new routes using non-toxic compounds have been researched. The proposal of the present study was to synthesize AgNPs using ribose as a reducing agent and sodium dodecyl sulfate (SDS) as a stabilizer. The antifungal activity of these particles against C. albicans and C. tropicalis was also evaluated. Stable nanoparticles 12.5 ± 4.9 nm (mean ± SD) in size were obtained, which showed high activity against Candida spp. and could represent an alternative for fungal infection treatment.

TUBERCULOSIS INFECTION MIGHT INCREASE THE RISK OF INVASIVE CANDIDIASIS IN AN IMMUNOCOMPETENT PATIENT

Deep Candida infections commonly occur in immunosuppressed patients. A rare case of a multiple deep organ infection with Candida albicansand spinal tuberculosis was reported in a healthy young man. The 19-year-old man complained of month-long fever and lower back pain. He also had a history of scalded mouth syndrome. Coinfection with Mycobacterium tuberculosis and Candida albicans was diagnosed using the culture of aspirates from different regions. Symptoms improved considerably after antifungal and antituberculous therapy. This case illustrates that infection with tuberculosis might impair the host's immune system and increase the risk of invasive candidiasis in an immunocompetent patient.

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.

SUSCEPTIBILITY TEST FOR FUNGI: CLINICAL AND LABORATORIAL CORRELATIONS IN MEDICAL MYCOLOGY

SUMMARYDuring recent decades, antifungal susceptibility testing has become standardized and nowadays has the same role of the antibacterial susceptibility testing in microbiology laboratories. American and European standards have been developed, as well as equivalent commercial systems which are more appropriate for clinical laboratories. The detection of resistant strains by means of these systems has allowed the study and understanding of the molecular basis and the mechanisms of resistance of fungal species to antifungal agents. In addition, many studies on the correlation of in vitro results with the outcome of patients have been performed, reaching the conclusion that infections caused by resistant strains have worse outcome than those caused by susceptible fungal isolates. These studies have allowed the development of interpretative breakpoints for Candida spp. and Aspergillus spp., the most frequent agents of fungal infections in the world. In summary, antifungal susceptibility tests have become essential tools to guide the treatment of fungal diseases, to know the local and global disease epidemiology, and to identify resistance to antifungals.

FACTORS RELATED TO ORAL CANDIDIASIS IN ELDERLY USERS AND NON-USERS OF REMOVABLE DENTAL PROSTHESES

This study examined the association between oral candidiasis in elderly users and nonusers of prosthesis and its predisposing factors. To this end, we performed a cross-sectional study where saliva samples from 48 patients were collected they used prosthesis and 43 patients (control group) who did not use. Among the 91 patients, Candida spp were isolated in 40 (83.3%) who used prosthesis and in 23 (53.5%) in the control group. A statistically significant association was determined between the two groups, the isolation of yeasts and dental prosthesis (p < 0.05, OR = 4.3). The most common etiological agent was Candida albicans (37 isolates), with 23 (62.2%) in the denture group and 14 (37.8%) (control group). Among patients who presented clinical manifestations of oral candidiasis (n = 24), 83.3% (n = 20) belonged to the group that wore dentures, while only 16.7% (n = 4) belonged to the control group. Elderly patients with diabetes had 4.4 times higher estimated risk of developing oral candidiasis when compared with individuals without this condition. There was no statistically significant association between being user prostheses and have diabetes with the onset of candidiasis. No statistically significant association was determined between xerostomia, use of prosthesis and oral candidiasis. The use of prosthetics and poor oral hygiene in elderly patients predisposes to the development of oral candidiasis.

Candidíase em pacientes aidéticos

Trinta e cinco aidéticos entre 19 e 55 anos admitidos e tratados de candidíase no Hospital Emílio Ribas, SP, com ELISA positivo para HIV e confirmado pelo Western Blot. Tuberculose em 9 sendo 2 com pericardite; neurotoxoplasmose em 6; neurocriptococose em 5; herpes labial em 4; pneumocistose em 3 e sarcoma de Kaposi em 2, achavam-se associadas. A concentração inibitória mínima 50% (MIC 50%) para os azoles foi: ketoconazol= 2,2 µg/ml; itraconazol- 21,0 µg/ml; fluconazol = 19,0 µg/ml. O MIC 50% para ospolienos: nistatina- 50,0 µg/ml; anfotericina B= 0,12 µg/ml e para 5 fluorcitosina= 1,6 µg/ml nas 35 amostras de Candida isoladas. Testes não paramétricos de Siegel revelaram significante identificação (80%) das Candida albicans na candidíase, e que a dose de AMB não modificou o número de óbitos, precoce e tardio, ocorridos nesses aidéticos. O uso prévio dos azoles e da nistatina explicaria, talvez, o elevado MIC 50% observado nas amostras de Candida isoladas.

Candidíase em pacientes transplantados renais

O objetivo do trabalho foi verificar a prevalência de candidíase em transplantados renais. Foram avaliados os prontuários dos pacientes transplantados no Hospital das Clínicas de Ribeirão Preto de fevereiro de 1968 a fevereiro de 1995. Nesse período foram transplantados 620 pacientes. Destes, 87 apresentaram 107 episódios de candidíase. Locais mais acometidos: trato urinário com 55 episódios, trato respiratório com 28, e trato gastrointestinal com 16. O agente etiológico mais freqüente foi C. albicans com 65 casos seguido de C. tropicalis com 12 e C. glabrata com 11 casos. As infecções do trato urinário mostraram incidência maior (61,7%) nos primeiros 6 meses. A maioria se apresentou clínicamente como infecção bacteriana. No trato respiratório, as infecções foram caracterizadas por recuperação do agente no escarro. No trato gastrointestinal, 9/16 episódios foram esofágicos, com epigastralgia, dor retroesternal, às vezes acompanhados de candidíase oral ou odinofagia. Nos outros episódios o agente foi recuperado nas fezes com quadro clínico de gastroenterite. Nas infecções dos tratos urinário e respiratório, houve associação da candidíase com antibioticoterapia prévia (76% e 67% respectivamente), além de infecções bacterianas concomitantes (34% e 64% respectivamente). As infecções por Candida sp tiveram prevalência geral em torno de 14,5%. A localização predominante foi no trato urinário e, em seguida, nos tratos respiratório e gastrointestinal, apresentando alto índice de associação com antibioticoterapia prévia e infecções bacterianas.

Alterações anatomopatológicas renais em indivíduos com a síndrome da imunodeficiência adquirida

As alterações anatomopatológicas renais foram estudadas em 119 casos de indivíduos com a síndrome da imunodeficiência humana adquirida (SIDA) no Hospital Escola da Faculdade de Medicina do Triângulo Mineiro, Uberaba MG. A partir das amostras de rim fixadas em formol, foram confeccionadas lâminas e analisadas ao microscópio de luz. Dos 119 casos estudados, 67 tiveram diagnóstico de nefrite túbulo intersticial (NTI), sendo 18 inespecíficas, 2 xantogranulomatosas e encontrou-se agente infeccioso em 48: fungos em 28 (16 Cryptococcus sp, 9 Histoplasma sp, 1 Candida sp e 2 Paracoccidioides brasiliensis); bactérias em 18 (9 Mycobacterium sp); vírus em 6, Citomegalovírus. Em 43 havia necrose tubular aguda (NTA). Outros diagnósticos foram: nefrocalcinose (15,1%) e hialinose arteriolar (22,7%). Encontrou-se também 2 casos com glomeruloesclerose segmentar focal (GESF) e um caso de hiperplasia mesangial difusa. Houve predomínio da NTI, que pode ser devido às infecções oportunistas, predominando as fúngicas; a toxicidade por drogas ou ainda devido a possível ação direta do próprio vírus. A necrose tubular aguda (NTA), foi a segunda causa em freqüência, de acometimento renal da amostra. Concluiu-se que o envolvimento renal nos pacientes com SIDA apresenta um espectro variado de processos patológicos, principalmente relacionados com infecções oportunistas, o tratamento e os procedimentos para diagnósticos, e ainda as nefropatias associadas ao vírus da imunodeficiência humana (VIH).

Inquérito soroepidemiológico para infecções por fungos causadores de micoses sistêmicas na Reserva Indígena Xacriabá, Estado de Minas Gerais

A Reserva Indígena Xacriabá situa-se no norte do Estado de Minas Gerais, próxima do município de Manga e do vale do Rio São Francisco. A população índia é miscigenada com brancos e negros e exerce atividades agrícolas e pecuária. Amostras de sangue foram coletadas de 180 habitantes da Reserva (85 homens e 95 mulheres), com 15 a 84 anos de idade, testando-se o soro pelo método da contraimunoeletroforese com antígenos de Paracoccidioides brasiliensis, Histoplasma capsulatum, Cryptococcus neoformans e Candida albicans. Verificou-se soros reagentes em, respectivamente, 5%, 3,9%, 7,2% e 6,7% do total de amostras. Os indivíduos reativos com antígenos de P. brasiliensis e H. capsulatum eram predominantemente mulheres e tinham idade menor e títulos médios mais elevados de anticorpos do que os reativos com outros antígenos.Os resultados são sugestivos da ocorrência de paracoccidiodomicose-infecção e de histoplasmose-infecção, nas primeiras décadas de vida dos habitantes, na área da Reserva Indígena Xacriabá.

Identificação de agentes infecciosos pulmonares em autópsias de pacientes com a síndrome da imunodeficiência adquirida

As afecções pulmonares são freqüentes em indivíduos infectados pelo vírus da imunodeficiência humana. Neste trabalho, procurou-se identificar através de histoquímica e imunohistoquímica, agentes infecciosos nos pulmões de indivíduos portadores da síndrome da imunodeficiência adquirida (SIDA), autopsiados entre março de 1990 e julho de 2000 na FMTM. Fragmentos de pulmão de 40 indivíduos com SIDA autopsiados foram analisados histologicamente. Foram identificados agentes infecciosos em 34 (85%) casos dos 40 analisados, sendo que bactérias foram encontradas em 22 (55%) casos. Entre os agentes fúngicos o Pneumocystis carinii foi encontrado em oito (19,1%) casos; Cryptococcus sp em quatro (9,5%), Histoplasma sp em dois (4,8%) e Candida sp em um (2,4%) caso. Detectou-se também associação entre Pneumocystis carinii, Citomegalovirus e Cryptococcus sp; CMV e Toxoplasma gondii. Em cinco casos, Candida sp, CMV e Pneumocystis carinii estiveram associados a bactérias. Entre as infecções não bacterianas, os fungos foram os agentes infecciosos mais isolados dos pulmões em autópsias de indivíduos com SIDA, sendo o Pneumocystis carinii o mais freqüente.

Avaliação da resposta imune celular em pacientes com candidíase recorrente

A candidíase recorrente cutânea ou mucosa é caracterizada pela ocorrência de, no mínimo, 4 episódios de candidíase no período de um ano. Não são conhecidos os fatores que levam à recorrência desta infecção. O presente estudo avaliou a resposta linfoproliferativa e a produção de IFN-g de pacientes com candidíase recorrente. Os índices de estimulação da resposta linfoproliferativa em culturas de células de pacientes com candidíase recorrente estimuladas com antígeno de Candida albicans, PPD e TT foram respectivamente de 6±8, 17±20 e 65±30. A adição de anticorpo monoclonal anti-IL-10 às culturas de células de 6 pacientes aumentou a resposta linfoproliferativa de 735±415 para 4143±1746 cpm. A produção de IFN-g em culturas de células estimuladas com antígeno de Candida, foi 162±345pg/ml. Pacientes com candidíase recorrente apresentam uma deficiência na resposta linfoproliferativa e na produção de IFN-g, podendo a resposta imune celular ao antígeno de Candida ser restaurada parcialmente através da neutralização da IL-10 in vitro.

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.

Erucismo por Lonomia spp em Teresópolis, RJ, Brasil: relato de um caso provável e revisão da literatura

Relata-se o caso de um homem de 44 anos, natural do Rio de Janeiro, residente no município de Teresópolis (RJ), vítima de um provável acidente por lagarta do gênero Lonomia, que evoluiu com quadro caracterizado por anemia hemolítica, plaquetopenia e insuficiência renal aguda. O diagnóstico de erucismo por Lonomia foi estabelecido a partir da anamnese e das manifestações clínicas e laboratoriais. O esquema terapêutico, baseado em hemodiálise e hemotransfusão, resultou em excelente resposta clínica. São discutidos os aspectos clínicos e fisiopatológicos do erucismo por Lonomia.