Analysis of gyrA mutations related to quinolone resistance in Escherichia coli isolates originating from pet, human, vegetable and ice in Bangkok and vicinity.

Escherichia coli was used to investigate quinolone resistance and mutations in gyrA gene of E. coli isolated from pet (dog and cat), human (pet's owner), vegetable and edible ice in Bangkok and vicinity. Susceptibility test for nalidixic acid (NA) showed similar percent resistance among the sample sources but a lower ciprofloxacin (CIP) resistance was found particularly in human source. Mutations within quinolone resistance determining region of gyrA gene analyzed using non-radioactive single-strand conformation polymorphism (SSCP) and sequencing showed 10 different SSCP patterns. E. coli isolates from pet, vegetable and ice showed more variety of patterns than strains isolated from human. Four out of 10 SSCP patterns were identified as having mutations in amino acids positions 83 (Ser to Leu) and position 87 (Asp to Asn). These mutations were observed only in NA-resistant strains and combined mutations were observed only in E. coli isolated from humans and pets. As only 24% of NA- and CIP-resistant E coli isolates contained gyrA mutations, other quinolone resistant mechanisms may be involved. Nevertheless, gyrA mutations may be used to monitor nalidixid acid resistance in E. coli.

Bacterial and yeast counts in brazilian commodities and spices

A total of thirteen genera of bacteria and two genera of yeasts were detected in surface sterilized and unsterilized Brazilian commodities and spices such as cashew kernels, Brazil nut kernels, black and white pepper. The genus Bacillus with eight species was by far the most common. The yeasts isolated were Pichia sp., P. guillermondii and Rhodotorula sp. Bacillus cereus, Salmonella typhimurium and Staphylococcus aureus were detected in cashew and Brazil nut kernels.

Siderophore production by fluorescent pseudomonads colonizing roots of certain crop plants.

Twelve fluorescent Pseudomonas isolates colonizing roots of four crop plants, chilli, cotton, groundnut and soybean, were examined for extracellular siderophore production in different media under iron deficient conditions. While all the organisms produced siderophores, they varied in the quantity of siderophores produced and in their preference to the medium. The siderophores were invariably hydroxamates (pyoverdine) of trihydroxamate type which formed bidentate ligands with Fe III ions.

Endosporos termófilos del ambiente azucarero de Jujuy / Thermophilic endospores in the environment of a sugar mill in Jujuy

Twenty six samples from green and scorched sugarcane stems and leaves, sugarmill air dust and raw sugar were analyzed. Thirty nine thermophilic bacilli strains were isolated. Physiological and morphological examinations were carried out according to Bergey's Manual. The strains were identified as B. licheniformis (66.7), B. coagulans (17.9), B. stearothermophilus (10.3) y B. subtilis (5.1).

Antagonism of Yeasts to Xanthomonas Campestris PV. Campestris on Cabbage Phylloplane in field

Twenty yeast isolates, obtained from cabbage phylloplane, were evaluated for antagonistic activity against Xanthomonas campestris pv. campestris, in field. Plants of cabbage ev. Midori were pulverized simultaneously with suspensions of antagonists and pathogen. After 10 days, plants were evaluated through percentage of foliar area with lesions. Percentage of disease severity reduction (DSR per cent) was also calculated. Yeast isolates LR32, LR42 and LR19 showed, respectively, 72, 75 and 79 (per cent) of DSR. These antagonists were tested in seven different application periods in relation to pathogen inoculation (T1=4 d before; T2=simultaneously; T3=4 d after; T4=4 d before + simultaneously; T5=4 d after + simultaneously; T6=4 d before + 4 d after; T7=4 d before + simultaneously + 4 d after). The highest DSRs were showed by LR42 (71 per cent), LR42 (67 per cent), LR35 (69 per cent) and LR19 (68 per cent) in the treatments T7, T4, T5, and T6, which significantly differed from the others. The same yeast antagonists were also tested for back rot control using different cabbage cultivars (Fuyutoyo, Master-325, Matsukaze, Midori, Sekai I and Red Winner). The DSRs varied from 58 to 61 (per cent), and there was no significant difference among cultivars

Microhongos de la hierba mate (ilex paraguariensis st hil) / Microfungi of mate herb (ilex paraguariensis st hil)

Se estudió cuantitativa y cualitativamente la presencia de especies fúngicas mesófilicas, termotolerantes y termofilicas presentes en 10 muestras de yerba mate (ilex paraguariensis st. hil.) obtenidas de diversos locales comerciales de la capital federal del gran Buenos Aires. Mediante las técnicas de dilución en placa y cámara húmeda, se aislaron un total de 14 géneros y 15 especies. Los aislamientos más comunes fueron: aspergillus niger van tieghem ( en 110 por ciento de las muestras) y rhodotorula spp. (80 por ciento). Otros taxa menos frecuentes integraron los géneros aspergillus, penicillium, fusarium, paecilomyces y phaecoccomyces y algunas de ellos pueden considerarse potencialmente toxicogénicas. Cephaliophora tropica thaxter, melanospora sp., rhizomucor pusillus schipper y humicola grisea traaen, fueron unicamente recuperadas mediante la técnica de cultivo en cámara húmeda. El número de propágulos por gramo del producto analizado, osciló desde 2.700 a 50.000 ufc. para hongos mesofilicos y de 0-3000 ufc. para termotolerantes

In vitro inhibition of spores germination of Alternaria solani by three fungicides

Foram realizados 10 experimentos em condiçöes de laboratório, utilizando-se isolados selvagens locais do fungo Alternaria solani obtidos de folhas de tomateiro. O primeiro experimento consistiu na inoculaçäo de esporos em soluçöes dos fungicidas seguintes, cujas concentraçöes estäo expressas em ingredientes ativos (i.a.): iprodione 0,75 g/l. Outros nove experimentos foram realizados, concomitantemente, mas reduzindo-se as concentraçöes para:½, », 1/32, 1/64, 1/128, 1/256 e 1/512. Essas diluiçöes foram feitas em tubos de hemólise. Em todos os casos, foi incluído um tratamento testemunha, com água deionizada. Os cultivos experimentais foram mantidos em ambiente de 27 por cento. As avaliaçöes consistiram na determinaçäo da porcentagem dos esporos germinados em 5 campos microscópicos (aumento de 100 vezes) realizadas 6 horas e 9 horas após a inoculaçäo dos esporos em cada soluçäo de fungicida, sendo os dados transformados em arc. V sen p/100 para o tratamento estatístico. Na maior concentraçäo, todos os fungicidas inibiram a germinaçäo foram de 3 por cento, 18 por cento e 94 por cento respectivamente para iaprodione, chlorothalonil e água. Nos experimentos com menores concentraçöes dos fungicidas constatou-se significativos aumentos nas porcentagens de germinaçäo de esporos, exceto para anilazine, que manteve inibiçäo até a diluiçäo 1/64 (na avaliaçäo de 9 horas após inoculaçäo)

Pesquisa de contaminaçäo fecal em alfaces (Lactuca sativa) adquiridas em mercado da cidade de Juiz de Fora, Minas Gerais, Brasil / Research about fecal contamination of Lettuces (Lactuca sativa) which were got at the market of Juiz de Fora, MG, Brazil

Foi realizada, através de exames microbiológicos e parasitológicos, pesquisa sobre a contaminaçäo fecal em alfaces (Lactuca sativa) adquiridas em mercado da cidade de Juiz de Fora, MG, Brasil. Foram pesquisadas e encontradas bactérias Escherichia coli e larvas Strongyloides stercoralis, firmando a suposiçäo de contaminaçäo fecal e indicando as condiçöes sanitárias das hortaliças investigadas. Sugere-se às autoridades sanitárias um maior e efetivo controle da produçäo e comercializaçäo das hortaliças.

Thermophilic Streptomyces found in sugarcane environments in Jujuy, Argentina

Se describen cepas de Streptomyces termofilicos aisladas de polvo ambiental, restos de caña de azúcar y cachaza. Todos crecieron a 50-C en 48 h dando micelio aéreo con tonos grises. Los esporos, de 0,8 -1,0 x 1,0-1,4 µm, se tiñieron con verde de malaquita. Los Streptpomyces aislados fueron identificados con los siguientes "Williams' clusters". S.chromofuscus, S. cyaneus, S. microflavus, S. antibioticus, S. basdtedii y S. violaceusniger. Los tres últimos coinciden con las especies encontradas en bagazo de caña de azúcar de otras regiones del mundo

Observaciones sobre la histopatología de la viruela del apio / Histopathology of the smallpox of celery

Con el objeto de determinar la vía de penetración y posterior desenvolvimento de Septoria apiicola Speg, en hojas de apio, se desarrolló una técnica histopatológica de aclaramiento y tinción para poder efectuar esas observaciones. El micelio resultante de la germinación de las esporas penetra a través de los estomas y a partir de ellos se desenvuelve un micelio grueso, intercelular que forma picnidios con desarrollo sinfógeno. De ese micelio interno surgen a través de los estomas de 1 a 4 hifas gruesas y largas. Se supone que este es un medio más de diseminación que posee el hongo. Este mismo mecanismo se observó en S. Iycopersici Spet. y S. musiva Pk. por lo que se sospecha sea propio del género Septoria. Estudios adicionales confirmarán o no esta hipótesis