Prevalence and antifungal resistance profile of Candida spp. oral isolates from patients with type 1 and 2 diabetes mellitus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Oral Candida albicans isolates from HIV-positive individuals have similar in vitro biofilm-forming ability and pathogenicity as invasive Candida isolates

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genetic variability analysis among clinical Candida spp. isolates using random amplified polymorphic DNA

The patterns of genetic variation of samples of Candida spp. isolated from patients infected with human immunodeficiency virus in Vitória, state of Espírito Santo, Brazil, were examined. Thirty-seven strains were isolated from different anatomical sites obtained from different infection episodes of 11 patients infected with the human immunodeficiency virus (HIV). These samples were subjected to randomly amplified polymorphic DNA (RAPD) analysis using 9 different primers. Reproducible and complex DNA banding patterns were obtained. The experiments indicated evidence of dynamic process of yeast colonization in HIV-infected patients, and also that certain primers are efficient in the identification of species of the Candida genus. Thus, we conclude that RAPD analysis may be useful in providing genotypic characters for Candida species typing in epidemiological investigations, and also for the rapid identification of pathogenic fungi.

Staphylococcus spp., Enterobacteriaceae and Pseudomonadaceae oral isolates from Brazilian HIV-positive patients. Correlation with CD4 cell counts and viral load

The aim was to evaluate the presence of Staphylococcus spp., Enterobacteriaceae and Pseudomonadaceae in the oral cavities of HIV-positive patients. Forty-five individuals diagnosed as HIV-positive by ELISA and Western-blot, and under anti-retroviral therapy for at least 1 year, were included in the study. The control group constituted 45 systemically healthy individuals matched to the HIV patients to gender, age and oral conditions. Oral rinses were collected and isolates were identified by API system. Counts of microorganisms from HIV and control groups were compared statistically by a Mann-Whitney test (alpha = 5%). The percentages of individuals positive for staphylococci were similar between the groups (p = 0.764), whereas for Gram-negative rods, a higher percentage was observed amongst HIV-positive (p = 0.001).There was no difference in Staphylococcus counts between HIV and control groups (p = 0.1008). Counts were lower in the oral cavities of patients with low viral load (p = 0.021), and no difference was observed in relation to CD4 counts (p = 0.929). Staphylococcus aureus was the most frequently isolated species in HIV group, and Staphylococcus epidermidis was the prevalent species in the control group. Significantly higher numbers of enteric bacteria and pseudomonas were detected in the oral cavities of the HIV group than in the control (p = 0.0001). Enterobacter cloacae was the most frequently isolated species in both groups. Counts of enteric bacteria and pseudomonas were significantly lower in patients with low CD4 counts (p = 0.011); however, there was no difference relating to viral load. It may be concluded that HIV group showed greater species diversity and a higher prevalence of Enterobacteriaceae/Pseudomonadaceae. (C) 2011 Elsevier Ltd. All rights reserved.

VERIFICATION of THE PRESENCE of CAPSULE GENE SEQUENCES IN NASOPHARYNGEAL ISOLATES of NONTYPEABLE HAEMOPHILUS INFLUENZAE FROM HEALTHY CHILDREN AT A BRAZILIAN DAY CARE CENTER

Cinqüenta e oito cepas de Haemophilus influenzae foram isoladas da nasofaringe de crianças saudáveis que freqüentam uma creche, e através da técnica de Southern blot foi pesquisada nas cepas acapsuladas a presença de seqüências do gene capsular. Sete cepas (12%) caracterizadas sorologicamente como acapsuladas mostraram homologia com seqüências específicas da cápsula. Uma cepa foi caracterizada com uma linhagem H. influenzae tipo b cápsula deficiente.

Typing Candida albicans oral isolates from healthy Brazilian schoolchildren using multilocus enzyme electrophoresis reveals two highly polymorphic taxa

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Characterization of ndh gene of isoniazid resistant and susceptible Mycobacterium tuberculosis isolates from Brazil

Resistance in Mycobacterium tuberculosis to isoniazid (INH) is caused by mutations in the catalase-peroxidase gene (katG) , and within the inhA promoter and/or in structural gene. A small percentage (~ 10%) of INH-resistant strains do not present mutations in both of these loci. Other genes have been associated with INH resistance including the gene encoding for NADH dehydrogenase (ndh) . Here we report the detection of two ndh locus mutations (CGT to TGT change in codon 13 and GTG to GCG change in codon 18) by analyzing 23 INH-resistant and in none of 13 susceptible isolates from Brazilian tuberculosis patients. We also detected two isolates without a mutation in ndh, or any of the other INH resistance-associated loci examined, suggesting the existence of additional, as yet to be described, INH resistance mechanisms.

Potential of non-pathogenic Fusarium oxysporum isolates for control of Fusarium wilt of tomato

O trabalho avaliou a eficiência dos isolados (141/3, 233, 233/1, 245, 245/1, 251, 251/2, 251/5 e 257) de Fusarium oxysporum não patogênico ao tomateiro (Lycopersicon esculentum), no controle da murcha vascular causada por Fusarium oxysporum f. sp. lycopersici, raça 2 em plântulas de tomateiro cv. Viradoro. Para verificar o efeito dos isolados de F. oxysporum não patogênicos, o sistema radicular de plântulas de tomateiro, com 30 dias de idade, foi imerso na suspensão de conídios (10(6) ml-1) e as mudas transplantadas para substrato de cultivo. Após 35 dias do transplante foi verificado que esses isolados não foram patogênicos às plantas de tomateiro, nem afetaram o desenvolvimento das mudas. A eficiência dos isolados de Fusarium oxysporum não patogênicos no controle da murcha foi determinada imergindo-se as raízes de mudas de tomateiro em suspensão de conídios (10(6) conídios ml-1) e transplantando-as em substratos previamente infestados com os isolados de F. oxysporum f.sp. lycopersici, raça 2 (10(5) conídios ml-1 de substrato). Transcorridos 35 dias do transplante, foram realizadas as avaliações da severidade na escala de 1=planta sadia a 6=planta morta ou com vasos coloridos e folhas murchas até o ponteiro e altura das mudas. Os isolados de F. oxysporum não patogênicos foram eficientes em reduzir a severidade da doença e em manter normal o seu desenvolvimento. Esses resultados evidenciam a atividade antagônica dos isolados de F. oxysporum não patogênico no controle da murcha vascular do tomateiro, causada por Fusarium oxysporum f. sp. lycopersici raça 2.

Virulence profile of ten Paracoccidioides brasiliensis isolates: association with morphologic and genetic patterns

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparison between E-test and CLSI broth microdilution method for antifungal susceptibility testing of Candida albicans oral isolates

Trinta Candida albicans isoladas de pacientes portadores de candidose oral e 30 Candida albicans isoladas de indivíduos controle foram estudadas. Testes de susceptibilidade in vitro foram realizados com anfotericina B, fluconazol, 5-flucitosina e itraconazol pelo método do Clinical and Laboratorial Standars Institute (CLSI) e por E-test. Os resultados obtidos foram analisados e comparados. Os valores de CIM foram semelhantes para amostras isoladas de pacientes portadores de candidose oral e indivíduos controle. A concordância entre os dois métodos foi de 66,7% para a anfotericina B, 53,33% para o fluconazol, 65% para a flucitosina e 45% para o itraconazol. de acordo com estes resultados, o método do E-test poderia ser uma alternativa para a triagem de casos de rotina pela sua simplicidade. Entretanto, este método não pode ser considerado como um substituto para o método de referência do CLSI.

Pathogenicities and GP43kDa gene of three Paracoccidioides brasiliensis isolates originated from a nine-banded armadillo (Dasypus novemcinctus)

We studied three different isolates of Paracoccidioides brasiliensis obtained from the mesenteric lymph node (D3LY1), the spleen (D3S1) and the liver (D3LIV1) of the same armadillo (Dasypus novemcinctus ).Pulmonal inflammatory area was evaluated by intravenous inoculation of 10(6) yeast cells of each isolates in young, male, ddY mice. Moreover, the partial sequence of GP43kDa gene of P. brasiliensis was analyzed. The lung inflammatory area was greater in animals inoculated with isolate D3S1. The partial sequence of GP43kDa gene indicated that isolate D3S1 is different from isolates D3LY1 and D3LIV1. This study suggested that the same armadillo might be susceptible to multiple P. brasiliensis isolates simultaneously.

PATHOGENICITY AND IMMUNOGENICITY OF PARACOCCIDIOIDES-BRASILIENSIS ISOLATES IN THE HUMAN-DISEASE AND IN AN EXPERIMENTAL MURINE MODEL

The pathogenicity and immunogenicity of six recently isolated Paracoccidioides brasiliensis samples derived from patients presenting distinct and well defined clinical forms of paracoccidioidomycosis (PCM) were compared as to their virulence, tropism to different organs and ability to induce specific cellular and humoral immune response in susceptible (B10.A) inbred mice. Isolates Pb44 and Pb47 were obtained from acute cases, Pb50 from a chronic severe form, Pb45 from a chronic moderate case and both Pb56 and Pb57 from chronic mild forms of PCM. Pathogenicity and tropism of each fungal sample were evaluated by LD50% estimation, examination of gross lesions on various organs at 2, 4, 12 and 16 weeks post-infection, and by colony-forming unit (CFU) counts in the lungs at week 16 post-infection of mice. Fungal tropism in human PCM and in B10.A mice was always dissociated. A well defined relationship between virulence of the fungal sample and the clinical findings of the correspondent patient was not evident, although a tendency to higher LD50% and less intense paracoccidioidic lesions was observed in mice infected with Pb56 and Pb57. The specific DTH response patterns varied according to the infectant sample, but positive DTH reactions at the beginning of the infection and a tendency to anergy or low DTH responses at week 12 and/or week 16 post-infection were always observed. A correspondence between the DTH response in humans and in mice was noticeable only when the isolates from the most benign cases (Pb56 and Pb57) were considered. The specific antibody patterns in mice and in the correspondent patients were also not analogous. Collectively, these results indicate that an association between the fungal pathogenicity and immunogenicity in the human disease and in susceptible mice was discernible only when isolates obtained from very mild cases (Pb56 and Pb57) were considered.

Evaluation of the in vitro activity of cefepime compared to other broad-spectrum cephalosporins against clinical isolates from eighteen Brazilian hospitals by using the Etest

The in vitro activity of cefepime was compared to that of ceftazidime, ceftriaxone, and cefotaxime in a multicenter study involving 10 clinical microbiology laboratories and clinical isolates from 18 Brazilian hospitals from 7 cities (4 states). A total of 982 isolates consecutively collected between December 1995 and March 1996 were susceptibility tested by using Etest and following the NCCLS procedures for agar diffusion tests. The cefepime spectrum was broader than that of the other broad-spectrum cephalosporins against both Gram-negative rods and Gram-positive cocci. Cefepime tons particularly move active against Enterobacter sp. (MIC90, 2 mu g/ml), Serratia sp. (MIC90, 2 mu g/ml) and oxacillin-susceptible Staphylococcus aureus (MIC90, 3 mu g/ml). Against Pseudomonas aeruginosa, cefepime (MIC90 16 mu g/ml) was slightly more active than ceftazidime (MIC90 32 mu g/ml) and 8- to 16-fold more active than ceftriaxone or cefotaxime (MIC90 >256 mu g/ml). Our results show that nosocomial bacteria, especially Gram-negative rods, have a high rate of cephalosporin resistance in Brazil. However, part of these resistant bacteria remains susceptible to cefepime. The Etest was shown to be an excellent method for multicenter studies of the in vitro evaluation of new antimicrobial agents. (C) 1997 Elsevier B.V.

Origins of sequence diversity in the malaria vaccine candidate merozoite surface protein-2 (MSP-2) in Amazonian isolates of Plasmodium falciparum

The recent evolution of Plasmodium falciparum is at odds with the extensive polymorphism found in most genes coding for antigens. Here, we examined the patterns and putative mechanisms of sequence diversification in the merozoite surface protein-2 (MSP-2), a major malarial repetitive surface antigen. We compared the msp-2 gene sequences from closely related clones derived from sympatric parasite isolates from Brazilian Amazonia and used microsatellite typing to examine, in these same clones, the haplotype background of chromosome 2, where msp-2 is located. We found examples of msp-2 sequence rearrangements putatively created by nonreciprocal recombinational events, such as replication slippage and gene conversion, while maintaining the chromosome haplotype. We conclude that these nonreciprocal recombination events may represent a major source of antigenic diversity in MSP-2 in P falciparum populations with low rates of classical meiotic recombination. (c) 2006 Elsevier B.V. All rights reserved.