THE REGULARITIES OF IRON COMPOUNDS TRANSFORMATION BY CITROBACTER FREUNDII MI-31.1/1.

The purpose ofthe work was to study the regularities ofFe(III) compounds reduction under the conditions of limited aeration by the strain Citrobacterfreundii Ml-31.1/1, and to assess the role ofFe(II)-reducing bacteria (FRB) in iron compounds transformation in ecosystems. The following methods were used: cultivation of microorganisms under the conditions of limited aeration, colorimetric determination ofbiomass and Fe(III) and Fe(I) compounds concentra- tion, the potentiometric measuring ofpH and Eh, gas chromatography. Results: Thermody- namic calculations of microbial interaction with iron compounds were experimentally verified The regularities of Fe(III) and Fe(I) compounds transformation by the model strain Citro- bacterfreundii Ml-31.1/1, isolatedfrom the typical mid-latitude ecosystem -river sludge were obtained. The balance ofiron compounds redistribution in cells and in the extracellularfraction was established Conclusions: The results obtained are the basis to assume that non-specific interaction of microorganisms with iron may significantly influence transformation of iron. Thermodynamic prognosis allows to carry out targeted regulation of microbial metabolism.

Etiologia e perfil de sensibilidade de bactérias isoladas de ovelhas com mastite na região nordeste do estado do Pará / Etiology and antimicrobial susceptibilities of bacteria isolated from sheep with mastitis in northeastern Pará, Brazil

Objetivou-se com este trabalho estudar a etiologia da mastite em ovelhas na região nordeste do Pará, além de estabelecer o perfil de sensibilidade das bactérias isoladas frente a antimicrobianos. Foram examinadas 176 ovelhas da raça Santa Inês, em lactação, mantidas em sistema semi-intensivo, pertencentes a sete propriedades especializadas na criação de ovinos. Foi realizado o exame clínico da glândula mamária, o exame macroscópico da secreção láctea por meio do Teste da Caneca Telada, o California Mastitis Test (CMT), o exame microbiológico do leite e o antibiograma. Das 352 metades mamárias estudadas (176 ovelhas), 21 (5,97 por cento) apresentaram mastite clínica, 26 (7,39 por cento) apresentaram mastite subclínica e 305 (86,64 por cento) metades mamárias foram negativas. A maioria dos animais acometidos pela mastite estava no terço médio da lactação, com menor número de crias e maior número de lactações. Na mastite clínica (MC) as bactérias isoladas foram Staphylococcus spp. coagulase negativo (42,9 por cento); Staphylococcus aureus (9,52 por cento); Streptococcus spp. (4,76 por cento) e Escherichia coli (4,76 por cento). As associações observadas foram Staphylococcus aureus e Streptococcus spp. (4,76 por cento); Staphylococcus spp. coagulase negativo não hemolítica, Staphylococcus spp. coagulase negativo hemolítica e Staphylococcus spp. coagulase negativo pigmento não hemolítica (4,76 por cento). Já na mastite subclínica (MSC), as bactérias isoladas foram Staphylococcus spp. coagulase negativo (26,9 por cento); Staphylococcus aureus (15,4 por cento); Streptococcus spp. (7,69 por cento); Escherichia coli (7,69 por cento) e Citrobacter freundii (11,5 por cento). A associação observada foi Staphylococcus spp. coagulase negativo não hemolítica e Staphylococcus spp. coagulase negativo hemolítica (3,85 por cento). Os antimicrobianos com maior eficácia contra os agentes isolados Gram positivos foram penicilina/novobiocina (100 por cento), cefalotina (100 por cento) e florfenicol (100 por cento) e contra o Citrobacter freundii foram a ampicilina (100 por cento) e florfenicol (100 por cento). Já em relação a Escherichia coli, 66,7 por cento dos isolados mostraram-se resistentes à ampicilina, cefalotina, florfenicol e tetraciclina. A mastite está presente em ovelhas no estado do Pará, havendo a necessidade de estimar, em estudos futuros, as perdas econômicas causadas por essa enfermidade. O CMT apresentou resultados satisfatórios, podendo ser recomendado como teste de triagem para o diagnóstico de casos individuais de mastite subclínica em ovinos, uma vez que apresentou boa relação com o exame microbiológico. No antibiograma foi observado que a maioria dos agentes isolados apresenta-se sensível aos diferentes antimicrobianos testados, sendo os antibióticos com melhor eficiência o florfenicol e a cefoxitina.

The objective of this paper was to study the etiology of mastitis in sheep at northeastern Pará, and to establish the sensitivity of isolated bacteria to antibiotics. A total of 176 Santa Inês nursing sheep kept in semi-intensive system from seven properties were examined. The mammary gland was clinically examined and the milk was submitted to the Caneca Telada Test, the California Mastitis Test (CMT), bacteriological examinations and antibiograms. Out of the 352 mammary halves (176 sheep), 5.9 percent (21/352) had clinical mastitis and by the CMT test, 7.39 percent (26/352) had subclinical mastitis and 86.64 percent (305/352) mammary halves did not have mastitis. Most of the animals with mastitis were in the second third of the lactation period, had less kids and more lactation periods. The following bacteria were isolated from the clinical mastitis Staphylococcus spp. coagulase negative (42,9 percent); Staphylococcus aureus (9.52 percent); Streptococcus spp. (4.76 percent) and Escherichia coli (4.76 percent). Were observed associations of Staphylococcus aureus and Streptococcus spp. (4,76 percent); Staphylococcus spp. coagulase negative nonhemolytic, Staphylococcus spp. coagulase negative hemolytic and Staphylococcus spp. coagulase negative non hemolytic pigment (4.76 percent). Already in subclinical mastitis the bacteria isolated were Staphylococcus spp. coagulase negative (26.9 percent); Staphylococcus aureus (15.,4 percent); Streptococcus spp. (7.69 percent); Escherichia coli (7.69 percent) and Citrobacter freundii (11.5 percent). Were observed associations of Staphylococcus spp. coagulase negative nonhemolytic and Staphylococcus spp. coagulase negative hemolytic (3.85 percent). The most efficient antibiotics for the Gram positive agents were penicile/novobiocine (100 percent), cefalotine (100 percent) and florfenicol (100 percent) and for the Citrobacter freundii were ampicilina (100 percent) and florfenicol (100 percent). In relation to Escherichia coli, 66.7 percent of isolates to ampicillin, cephalothin, florfenicol and tetracycline were resistant. Mastitis is present in sheep in the State of Pará, and it's necessary to estimate, in future studies, the economic losses caused by this disease. The CMT show satisfactory results and can be recommended as a screening test for diagnosing individual cases of subclinical mastitis in sheep, once had a good relationship with the microbiological examination. In the antibiogram where most of the isolated agents appear sensitive to different antibiotics tested, the antibiotics with the best efficiency were florfenicol and cefoxitin.

Utilization of aminoaromatic acids by a methanogenic enrichment culture and by a novel Citrobacter freundii strain.

Following incubation of mesophilic methanogenic floccular sludge from a lab-scale upflow anaerobic sludge bed reactor used to treat cattle manure wastewater, a stable 5-aminosalicylate-degrading enrichment culture was obtained. Subsequently, a Citrobacter freundii strain, WA1, was isolated from the 5-aminosalicylate-degrading methanogenic consortium. The methanogenic enrichment culture degraded 5-aminosalicylate completely to CH4, CO2 and NH4+, while C. freundii strain WA1 reduced 5-aminosalicylate with simultaneous deamination to 2-hydroxybenzyl alcohol during anaerobic growth with electron donors such as pyruvate, glucose or serine. When grown on pyruvate, C. freundii WA1 converted 3-aminobenzoate to benzyl alcohol and also reduced benzaldehyde to benzyl alcohol. Pyruvate was fermented to acetate, CO2, H2 and small amounts of lactate, succinate and formate. Less lactate (30%) was produced from pyruvate when C. freundii WA1 grew with 5-aminosalicylate as co-substrate.