Virulence, agr groups, antimicrobial resistance and epidemiology of Staphylococcus aureus isolated from bovine subclinical mastitis / Virulência, grupos agr, resistência a antimicrobianos e epidemiologia de isolados de Staphylococcus aureus obtidos de vacas com mastite

Fifty-two Staphylococcus aureus recovered from papillary ostium and milk samples collected from cows with subclinical mastitis and milking environments in three small dairy herds located in southeastern Brazil were subjected to PCR identification based on the thermonuclease (nuc) gene. All the strains were submitted to in vitro antimicrobial susceptibility testing, and we investigated the sequence types (STs), agr groups (I-IV), virulence genes encoding for Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs), biofilm-associated proteins, bi-component toxins, pyrogenic toxin superantigens, and enterotoxins. Screening for oxacillin resistance (2-6 µg/ml oxacillin), beta-lactamase activity assays, and PCR for the mecA/mecC genes detected 26 methicillin-susceptible S. aureus(MSSA) and 26 mec-independent oxacillin-nonsusceptible S. aureus (MIONSA). While MSSA isolates were found to be susceptible to all antimicrobial agents tested, or only resistant to penicillin and ampicillin, MIONSA isolates were multidrug-resistant. ST126-agr group II MSSA isolates were prevalent in milk (n=14) and carried a broad set of virulence genes (clfA, clfB, eno, fnbA, fiB, icaA, icaD, lukED, hla, and hlb), as well as the ST126-agr group II MIONSA isolated from milking liners (n=1), which also carried the eta gene. ST1-agr group III MIONSA isolates (n=4) were found in papillary ostium and milk, but most MIONSA isolates (n=21), which were identified in both papillary ostium and milking liners, were agr-negative and assigned to ST126. The agr-negative and agr group III lineages showed a low potential for virulence. Studies on the characterization of bovine-associated MSSA/MIONSA are essential to reduce S. aureus mastitis to prevent economic losses in dairy production and also to monitor the zoonotic potential of these pathogens associated with invasive infections and treatment failures in healthcare.

Cinquenta e dois isolados de Staphylococcus aureus obtidos de amostras colhidas do óstio papilar, do leite de vacas com mastite subclínica e do ambiente de ordenha em três fazendas de rebanhos leiteiros localizadas no sudeste do Brasil foram identificados por PCR para o gene da termonuclease (nuc). Todos os isolados foram testados para sensibilidade a antimicrobianos e foram investigados os sequence types (STs), grupos agr (I-IV) e genes de virulência que codificam Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs), proteínas associadas a biofilme, toxinas bi-componentes, toxinas pirogênicas com propriedades de superantígenos e enterotoxinas. Triagem para detecção de resistência à oxacilina (2-6 µg/ml oxacilina), ensaios de atividade de enzimas beta-lactamases e PCR para os genes mecA/mecC detectaram 26 estirpes de S. aureus sensíveis à meticilina (methicillin-susceptible S. aureus, MSSA) e 26 estirpes de S. aureus mec-negativas não sensíveis à meticilina (mec-independent oxacillin-nonsusceptible S. aureus, MIONSA). Enquanto os isolados MSSA foram sensíveis a todos os agentes antimicrobianos testados, ou apenas resistentes à penicilina e ampicilina, os isolados MIONSA foram multirresistentes. MSSA ST126-agr grupo II foram prevalentes no leite (n= 14) e apresentaram um amplo conjunto de genes de virulência (clfA, clfB, eno, fnbA, fiB, icaA, icaD, lukED, hla e hlb), assim como o isolado MIONSA ST126-agr grupo II proveniente de um insuflador (n= 1), o qual também apresentou o gene eta. MIONSA ST1-agr grupo III (n= 4) foram identificados no óstio papilar e leite, mas a maioria dos isolados MIONSA (n= 21), encontrados em óstios papilares e insufladores, foram agr-negativos e pertenceram ao ST126. As linhagens agr-negativas e agr grupo III apresentaram baixo potencial de virulência. Estudos sobre a caracterização de MSSA/MIONSA associados a bovinos são essenciais para a redução da mastite causada por S. aureus e de perdas econômicas na produção leiteira e, também, para o monitoramento do potencial zoonótico desses patógenos associados a infecções invasivas e falhas de tratamento em ambientes hospitalares.

Staphylococcal cassette chromosome mec elements from Staphylococcus intermedius group (SIG) isolates from dogs in a center for veterinary diagnostics in Brazil / Cassetes cromossômicos estafilocócicos mec de isolados do grupo Staphylococcus intermedius (GSI) de cães em um centro veterinário de diagnósticos no Brasil

ABSTRACT: Methicillin resistance in the Staphylococcus intermedius group (SIG) has emerged in small animal practice. Methicillin-resistant SIG (MRSIG) members have been implicated as causes of infections in both companion animals and humans. Staphylococcal cassette chromosome mec (SCCmec) elements carry the mecA/C genes, which encode for the transpeptidase PBP2a (PBP2') responsible for β-lactam antibiotic resistance in staphylococci. This study examined the SCCmec types of MRSIG isolates from different clinical specimens of dogs that exhibited methicillin MIC ≥ 0.5 μg/mL by an automated identification and susceptibility system in a Center for Veterinary Diagnostics in São Paulo, Brazil. Susceptibility to methicillin was determined by broth microdilution testing, and Oxoid® M.I.C.Evaluator® strips. PBP2a production was detected using a latex agglutination assay. SCCmec typing was performed according to the International Working Group on the Classification of Staphylococcal Cassette Chromosome Elements (IWG-SCC) guidelines. SCCmec type II (2A), SCCmec type III (3A), composite SCC structures consisting of a class A mec gene complex in addition to multiple ccr gene complexes, and non-typable SCCmec elements were reported in these MRSIG isolates. SCCmec type variants differing from those so far acknowledged by IWG-SCC were found, indicating new rearrangements in the genetic context of mecA in these canine MRSIG isolates.

RESUMO: A resistência à meticilina no grupo Staphylococcus intermedius (GSI) tem aumentado na clínica de pequenos animais. Membros GSI resistentes à meticilina (GSIRM) têm sido causas de infecções tanto em animais de companhia e humanos. Cassetes cromossômicos estafilocócicos mec (SCCmec) carregam os genes mecA/C, que codificam a transpeptidase PBP2a (PBP2') responsável pela resistência aos antibióticos β-lactâmicos em estafilococos. Nosso objetivo foi investigar os elementos SCCmec de GSIRM isolados de diferentes amostras clínicas de cães que exibiram CIM de meticilina ≥ 0,5 μg/mL por meio de um sistema automatizado em um Centro Veterinário de Diagnósticos em São Paulo, Brasil. A sensibilidade à meticilina foi determinada por meio do teste de microdiluição em caldo e fitas Oxoid® M.I.C.Evaluator®. A produção de PBP2a foi detectada usando um ensaio de aglutinação de látex. A tipagem dos elementos SCCmec foi realizada de acordo com as diretrizes do International Working Group on the Classification of Staphylococcal Cassette Chromosome Elements (IWG-SCC). SCCmec tipo II (2A), SCCmec tipo III (3A), SCC compostos de um complexo mec de classe A com múltiplos complexos ccr, e elementos SCCmec não tipáveis foram encontrados nesses isolados GSIRM. Variantes que diferem dos elementos SCCmec reconhecidos até o momento pelo IWG-SCC foram encontradas, indicando novos rearranjos no contexto genético de mecA nesses isolados GSIRM caninos.

Emergence of carbapenem-resistant Acinetobacter pittii carrying the blaOXA-72 gene in the Amazon region, Brazil.

We sought to characterize the genetic context of blaOXA-72 gene in a carbapenem-resistant Acinetobacter pittii strain recovered from a hospitalized patient from Belém, North Brazil, in the Amazon region. We found that the blaOXA-72 gene was carried by a small plasmid, pIEC338SCox, that is 10,498 bp. The gene is flanked by XerC/XerD-like recombinase sites, which suggests that this gene was acquired onto this plasmid by recombination.

Do different probing depths exhibit striking differences in microbial profiles?

AIM: To perform a thorough characterization of the subgingival microbiota of shallow, moderate and deep sites in subjects with chronic periodontitis (ChP). MATERIAL AND METHODS: Subgingival samples were collected from subjects with ChP (n = 3/category of probing depth: ≤3, 4-6 and ≥7 mm) and periodontal health (PH). Individual samples were submitted to 16S rDNA high- throughput sequencing and the analysis was made using mothur and R packages. RESULTS: Nine subjects with ChP and seven with PH were included and 101 samples were evaluated. Thirteen phyla, 118 genera and 211 OTUs were detected. Taxa from Chloroflexi and Spirochaetes phyla were associated with initial stages of disease. Fretibacterium, Eubacterium[XI][G-6], Desulfobulbus, Peptostreptococcaceae[XI][G-1] and [G-3], Bacteroidetes[G-3], Bacteroidaceae[G-1] genera and Filifactor alocis, Fretibacterium fastidiosum, Johnsonella spHOT166, Peptostreptococcaceae[XIII][G-1]HOT113, Porphyromonas endodontalis and Treponema sp. HOT258, which are not conventionally associated with disease, increased with the deepening of the pockets and/or were elevated in ChP; while Streptococcus, Corynebacterium and Bergeyella genera were associated with PH (p < .05). CONCLUSION: Striking differences were observed between the microbiota of shallow and moderate/deep sites, but not between moderate and deep sites in ChP subjects. Differences between shallow sites in PH and ChP were also observed. The characterized microbiota included known oral microorganisms and newly identified periodontal taxa, some of them not-yet-cultured.

Molecular mechanisms of membrane impermeability in clinical isolates of Enterobacteriaceae exposed to imipenem selective pressure.

Intrinsic mechanisms leading to carbapenem-induced membrane impermeability and multidrug resistance are poorly understood in clinical isolates of Enterobacteriaceae. In this study, molecular behaviours during the establishment of membrane impermeability in members of the Enterobacteriaceae family under imipenem selective pressure were investigated. Clinical isolates (n = 22) exhibiting susceptibility to multiple antibiotics or characterised as extended-spectrum ß-lactamase (ESBL)- or AmpC-producers were submitted to progressive passages on Mueller-Hinton agar plates containing subclinical concentrations of imipenem [0.5 × the minimum inhibitory concentration (MIC)]. Changes in outer membrane permeability were evaluated by determination of antimicrobial MICs, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), and gene expression analysis related to membrane permeability (i.e. omp35-like, omp36-like and acrA) and regulatory mechanisms (i.e. marA and ompR) by quantitative reverse transcription PCR. Following imipenem induction, 73% of isolates showed increased carbapenem MICs by ≥2 doubling dilutions. At an early stage of treatment, imipenem modulated the expression of porins and efflux pump genes, represented by a reduction of 78% in omp36-like and a two-fold increase in acrA expression. Transcriptional factors marA and ompR were also affected by imipenem induction, increasing mRNA expression by 14- and 4-fold, respectively. High marA expression levels were associated with higher values of acrA expression. These results suggest that imipenem is an important factor in the development of an adaptive response to carbapenems by regulating key genes involved in the control of efflux pumps and porins, which could lead to a multidrug-resistant profile in clinical isolates, contributing to possible treatment failure.

Complete Genome Sequence of Staphylococcus aureus FCFHV36, a Methicillin-Resistant Strain Heterogeneously Resistant to Vancomycin.

We report here the sequence of the entire chromosome of Staphylococcus aureus strain FCFHV36, a methicillin-resistant strain heterogeneously intermediate to vancomycin, bearing a type II staphylococcal chromosome cassette mec element (SCCmec), belonging to multilocus sequence type (MLST) 105, and isolated from a vertebra of a patient with osteomyelitis.

Complete Genome Sequence of Lactococcus lactis Strain AI06, an Endophyte of the Amazonian Açaí Palm.

We report the genome, in a single chromosome, of Lactococcus lactis strain AI06, isolated from the mesocarp of the açaí fruit (Euterpe oleracea) in eastern Amazonia, Brazil. This strain is an endophyte of the açaí palm and also a component of the microbiota of the edible food product.

Complete nucleotide sequences of two blaKPC-2-bearing IncN Plasmids isolated from sequence type 442 Klebsiella pneumoniae clinical strains four years apart.

We sequenced the oldest blaKPC-2-bearing plasmid isolated in Brazil and another plasmid also carried by a Klebsiella pneumoniae strain of sequence type 442 (ST442), isolated 52 months later. Both plasmids present an IncN backbone and few acquired regions. Because the 2005 plasmid presented deletions and a truncated gene within Tn4401b compared to the 2009 plasmid, we can thus infer that IncN blaKPC-2-bearing plasmids pFCF1305 and pFCF3SP had a common ancestor circulating in Brazil prior to May 2005.

Presence of blaTEM-116 gene in environmental isolates of Aeromonas hydrophila and Aeromonas jandaei from Brazil

It is known that Aeromonas spp. possess different chromosomal â-lactamase genes. Presence and phenotypic expression of blaTEM, blaSHV, and blaCTX-M ESBL-encoding genes were investigated in environmental water isolates of Aeromonas hydrophila and Aeromonas jandaei. Presence of blaSHV and blaCTX-M genes was not observed, and blaTEM gene was verified in 91 percent of the isolates. Sequencing of 10 fragments showed the occurrence of blaTEM-116.

Methicillin/Oxacillin-resistant Staphylococcus aureus as a hospital and public health threat in Brazil.

Methicillin-resistant Staphylococcus aureus is an established nosocomial pathogen (HA-MRSA, hospital acquired MRSA), but has recently begun to appear in the community (CA-MRSA, community acquired MRSA). The cause of resistance to methicillin and all other beta-lactam antibiotics is the mecA gene, which is situated on a mobile genetic element, the Staphylococcal Cassette Chromosome mec (SCCmec). Seven major variants of SCCmec, type I to VII are distinguished. HA-MRSA disseminated worldwide and causes the majority of S. aureus nosocomial infections with a limited number of clones disseminated including the Brazilian Epidemic Clone (BEC, ST239-MRSA-III). CA-MRSA isolates are susceptible to non-beta-lactam antibiotics, usually isolated from healthy individuals which do not possess any unknown risk factors for MRSA infection and are associated with a larger clonal diversity compared with HA-MRSA. However, during recent years distinction between HA-MRSA and CA-MRSA is beginning to fade. Actually, knowledge about MRSA disseminating clones is required to implement any strategies to control the transmission of MRSA either within hospitals or in community. For this reason, rapid identification of strains is an important issue. The rate of HA-MRSA can be reduced substantially through the implementation of interventions strategies, even in settings where MRSA is endemic as in most Brazilian hospitals. However, these policies could be quite complicated in the light of an increasing CA-MRSA prevalence in healthcare facilities, considering that distinction between HA-MRSA and CA-MRSA has started to disappear.

Methicillin/Oxacillin-resistant Staphylococcus aureus as a hospital and public health threat in Brazil

Methicillin-resistant Staphylococcus aureus is an established nosocomial pathogen (HA-MRSA, hospital acquired MRSA), but has recently begun to appear in the community (CA-MRSA, community acquired MRSA). The cause of resistance to methicillin and all other â-lactam antibiotics is the mecA gene, which is situated on a mobile genetic element, the Staphylococcal Cassette Chromosome mec (SCCmec). Seven major variants of SCCmec, type I to VII are distinguished. HA-MRSA disseminated worldwide and causes the majority of S. aureus nosocomial infections with a limited number of clones disseminated including the Brazilian Epidemic Clone (BEC, ST239-MRSA-III). CA-MRSA isolates are susceptible to non-â-lactam antibiotics, usually isolated from healthy individuals which do not possess any unknown risk factors for MRSA infection and are associated with a larger clonal diversity compared with HA-MRSA. However, during recent years distinction between HA-MRSA and CA-MRSA is beginning to fade. Actually, knowledge about MRSA disseminating clones is required to implement any strategies to control the transmission of MRSA either within hospitals or in community. For this reason, rapid identification of strains is an important issue. The rate of HA-MRSA can be reduced substantially through the implementation of interventions strategies, even in settings where MRSA is endemic as in most Brazilian hospitals. However, these policies could be quite complicated in the light of an increasing CA-MRSA prevalence in healthcare facilities, considering that distinction between HA-MRSA and CA-MRSA has started to disappear.

Presence of bla TEM-116 Gene in Environmental Isolates of Aeromonas Hydrophila and Aeromonas Jandaei from Brazil.

It is known that Aeromonas spp. possess different chromosomal ß-lactamase genes. Presence and phenotypic expression of bla TEM, bla SHV, and bla CTX-M ESBL-encoding genes were investigated in environmental water isolates of Aeromonas hydrophila and Aeromonas jandaei. Presence of bla SHV and bla CTX-M genes was not observed, and bla TEM gene was verified in 91% of the isolates. Sequencing of 10 fragments showed the occurrence of bla TEM-116.

Type IV SCCmec found in decade old Brazilian MRSA isolates.

Methicillin-resistant Staphylococcus aureus (MRSA) commonly causes infection in hospitalized patients. Since its appearance in the 1960s, the SCCmec has evolved throughout the years into 5 different types (I-V), each bearing a different set of genes. Infection with MRSA SCCmec types I, II or III is almost exclusively restricted to hospitalised patients. However, recently, community acquired MRSA (CA-MRSA) infections have been reported with increasing frequency, usually caused by a type IV SCCmec MRSA in nosocomial settings. We studied the prevalence of SCCmec types in 50 nosocomial strains collected from 1995 to 1999. The SCCmec complex type and presence of Panton-Valentine leukocidin (PVL) were determined by PCR. Strains had been previously typed by PFGE and were now typed by MLST. We found that 3 of the isolates studied bore a type IVc SCCmec all having different PFGE and MLST profiles (ST3, ST5 and ST88). All strains bearing a type III SCCmec belonged to MLST ST239 (Brazilian/Iberian clone). Only the strain which presented the ST5 profile bore the pvl gene. The type IVc SCCmec strains presented relatively lower levels of resistance to oxacillin in comparison to the type III SCCmec strains. The pattern of dissemination of the type IV SCCmec remains to be elucidated. The finding of strains carrying a type IV SCCmec in the present study among strains isolated at least 7 years ago indicates that clones bearing a type IV SCCmec have been present in Brazil for quite some time, and must have gone by undetected.

Type IV SCCmec found in decade old Brazilian MRSA isolates

Methicillin-resistant Staphylococcus aureus (MRSA) commonly causes infection in hospitalized patients. Since its appearance in the 1960s, the SCCmec has evolved throughout the years into 5 different types (I-V), each bearing a different set of genes. Infection with MRSA SCCmec types I, II or III is almost exclusively restricted to hospitalised patients. However, recently, community acquired MRSA (CA-MRSA) infections have been reported with increasing frequency, usually caused by a type IV SCCmec MRSA in nosocomial settings. We studied the prevalence of SCCmec types in 50 nosocomial strains collected from 1995 to 1999. The SCCmec complex type and presence of Panton-Valentine leukocidin (PVL) were determined by PCR. Strains had been previously typed by PFGE and were now typed by MLST. We found that 3 of the isolates studied bore a type IVc SCCmec all having different PFGE and MLST profiles (ST3, ST5 and ST88). All strains bearing a type III SCCmec belonged to MLST ST239 (Brazilian/Iberian clone). Only the strain which presented the ST5 profile bore the pvl gene. The type IVc SCCmec strains presented relatively lower levels of resistance to oxacillin in comparison to the type III SCCmec strains. The pattern of dissemination of the type IV SCCmec remains to be elucidated. The finding of strains carrying a type IV SCCmec in the present study among strains isolated at least 7 years ago indicates that clones bearing a type IV SCCmec have been present in Brazil for quite some time, and must have gone by undetected.

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 (approximately 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.

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 percent) 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.

DOD/AMB: in vivo activity of a novel amb formulation with synthetic cationic bilayer fragments

A habilidade do brometo de dioctadecildimetilamônio (DOBAB), em formar bicamada de lipídio sintético e a demonstração prévia do forte poder solubilizante de anfotericina B (ANB) , incentivou-nos a realizar a avaliação da atividade de DODAB/AMB in vivo contra candidíase sistêmica em modelo de camundongos para verificar a sua sobrevida bem como a recuperação das leveduras de C. albicans dos órgãos colonizados (baço e rins). O AMB foi simplesmente adicionado à DODAB em pó previamente disperso em água e sonicado com auxílio de ponteiras, nas concentrações de <0,1e 10 mg/mL, respectivamente, assegurando-se a completa ausência de solventes orgânicos nesta formulação. O estado de agregação do AMB foi avaliado por meio do espectro de absorção da luz UV-visível e a distribuição de tamanhos das formulações estudadas, determinadas por meio de analisador ZetaPlus Brookhaven Instruments Corporation, Holtsville, NY) equipado com um laser de 570 nm e dynamic light scattering (90ºC) para a medição dos tamanhos (Grabowski & Morrison, 1983). AMB foi estabilizada na bicamada de DODAB em forma monomérica, eliminando-se os grandes agregados de AMB insolúveis em água. Tanto a sobrevida dos animais como os experimentos com recuperação das leveduras dos órgãos colonizados (baço e rins) mostraram eficácia equivalente à demonstrada por Fungizona (DOC/AMB) - a sobrevida foi de 100 e 70% respectivamente nas concentrações de 0.4 mg/kg/dia via i.p. por 10 dias (P>0.05), em relação a eliminação da colonização de C. albicans dos rins e baço. Em resumo, DOD/AMB foi efetivo no tratamento de candidíase sistêmica em modelo animal.

DOD/AMB: in vivo activity of a novel amb formulation with synthetic cationic bilayer fragments

The ability of the versatile dioctadecyldimethylammonium bromide (DODAB), a bilayer-forming synthetic lipid previously shown to solubilize Amphotericin B (AMB), inspired this evaluation of in vivo activity of the DODAB/AMB formulation (DOD/AMB) against systemic candidiasis in a mouse model from survival and tissue burden experiments. AMB was simply added to a DODAB powder dispersion in water previously obtained by sonication with tip at concentrations 0.1 and 10 mg/mL, respectively, organic solvents completely absent. AMB aggregation state was evaluated from UV-visible light absorption and dynamic light scattering for aggregate sizing. AMB was stabilized by the DODAB bilayer fragments in its monomeric form, causing disappearance of large water insoluble drug aggregates. From survival and tissue burden experiments, DOD/AMB efficacy was equivalent to the one exhibited by Fungizone (DOC/AMB) - 100 and 70% survival respectively, at 0.4 mg/kg/day given i.p. for 10 days (P>0.05) -, regarding elimination of Candida colonization in spleen and kidneys. In summary, DOD/AMB, was effective for treating systemic candidiasis in a mouse model.

A habilidade do brometo de dioctadecildimetilamônio (DOBAB), em formar bicamada de lipídio sintético e a demonstração prévia do forte poder solubilizante de anfotericina B (ANB) , incentivou-nos a realizar a avaliação da atividade de DODAB/AMB in vivo contra candidíase sistêmica em modelo de camundongos para verificar a sua sobrevida bem como a recuperação das leveduras de C. albicans dos órgãos colonizados (baço e rins). O AMB foi simplesmente adicionado à DODAB em pó previamente disperso em água e sonicado com auxílio de ponteiras, nas concentrações de 0,1e 10 mg/mL, respectivamente, assegurando-se a completa ausência de solventes orgânicos nesta formulação. O estado de agregação do AMB foi avaliado por meio do espectro de absorção da luz UV-visível e a distribuição de tamanhos das formulações estudadas, determinadas por meio de analisador ZetaPlus Brookhaven Instruments Corporation, Holtsville, NY) equipado com um laser de 570 nm e dynamic light scattering (90ºC) para a medição dos tamanhos (Grabowski & Morrison, 1983). AMB foi estabilizada na bicamada de DODAB em forma monomérica, eliminando-se os grandes agregados de AMB insolúveis em água. Tanto a sobrevida dos animais como os experimentos com recuperação das leveduras dos órgãos colonizados (baço e rins) mostraram eficácia equivalente à demonstrada por Fungizona (DOC/AMB) - a sobrevida foi de 100 e 70% respectivamente nas concentrações de 0.4 mg/kg/dia via i.p. por 10 dias (P>0.05), em relação a eliminação da colonização de C. albicans dos rins e baço. Em resumo, DOD/AMB foi efetivo no tratamento de candidíase sistêmica em modelo animal.

Ocorrência e determinaçäo do perfil de sensibilidade às drogas das cepas de Staphylococcus Aureus isoladas de fossas nasais e orofaringe dos servidores hospitalares / Frequency and antimicrobial susceptibility of Staphylococcus aureus strains isolated from hospital staff

O Staphylococcus aureus causa uma série de infecçöes, desde lesöes purulentas e localizadas da pele até infecçöes generalizadas e sistêmicas, sendo particularmente graves em indivíduos debilitados. A infecçäo hospitalar por este microrganismo representa um sério problema médico-social, sendo necessária a sua prevençäo e controle. Neste contexto, os pacientes e os servidores hospitalares säo considerados reservatórios e propagadores importantes desta bactéria. A ocorrência de cepas de S. aureus resistentes a oxacilina (MRSA), no entanto, tem contribuído para o agravamento desta situaçäo uma vez que se trata de germes caracterizados por apresentar resistência múltipla aos agentes antimicrobianos usualmente empregados na prática hospitalar. Portanto, o presente trabalho teve como objetivo investigar a ocorrência de S. aureus nos vestíbulos nasais e cavidade oral de servidoresde três hospitais de Bauru, e determinar o perfil de resistência das bactérias isoladas aos agentes antimicrobianos mais freqüentes. Dos 213 funcionários analisados, 94 (44,13 por cento) eram portadores de S. aureus e 47 (50 por cento) das cepas foram isoladas de fossas nasais, 23 (24,5 por cento) de cavidade oral e 24 (25,5 por cento) de ambos os sítios. As provas metabólicas realizadas mostraram que as cepas isoladas apresentaram 100 por cento de correlaçäo com a cepa de referência ATCC 29213. As 94 cepas apresentaram sensibilidade variada aos antimicrobianos testados verificando-se ausência de cepas vancomicina resistentes e apenas 8 (8,5 por cento) resistentes a oxacilina.