Antibacterial potential of essential oils against planktonic and sessile cells of Escherichia coli isolated from diarrhea cases in swine / Potencial antibacteriano de aceites esenciales contra células de Escherichia coli planctónicas y sésiles aisladas de diarrea porcina

Escherichia coli is a pathogen associated with infections in piglets in the post-weaning phase, its pathogenicity is related to the animal's susceptibility to bacterial enterotoxins. The objective of the present study was to determine the EOs activity against E. colistrain, in the form planktonic and sessile. Although the Disc-Diffusion tests to determine the Minimum Inhibitory Concentration, do not fully corroborate with the other analyzes of this study, it was noticed bacteria inhibition. The EOs were prepared at 0.4%, 0.8% and 1.0% for tests. The tested EOs were effective against E. coliplanktonic cells (p<0.05). As for the sessile cells, the most significant result was inhibition and 100% sessile cells at the concentration of 1.0% of Cymbopogon citratusEO. Although there was resistance in some treatments, the tested EOs demonstrated inhibition capacity, constituting promising alternatives for the control of E. coli, especially of planktonic cells.

Escherichia coli es un patógeno asociado con infecciones en lechones en la fase posterior al destete, su patogenicidad está relacionada con la susceptibilidad del animal a las enterotoxinas bacterianas. El objetivo del presente estudio fue determinar la actividad de contra E. coli, en la forma planctónico y sésil. Aunque las pruebas de difusión de disco para determinar la concentración inhibitoria mínima, no corroboran completamente con los otros análisis de este estudio, se observó inhibición de la bacteria. Las soluciones basadas en AE se prepararon al 0.4%, 0.8% y 1.0% para pruebas. Los AEs probados fueron efectivos contra las células planctónicas (p<0.05). En cuanto a las células sésiles, el resultado más significativo fue la inhibición y el 100% de las células sésiles a la concentración de 1,0% de Cymbopogon citratus. Aunque hubo resistencia en algunos tratamientos, los AEs probados demostraron capacidad de inhibición, constituyendo alternativas prometedoras para el control de E. coli, especialmente de células planctónicas.

Fascitis necrotizante / Necrotizing Fasciitis

RESUMEN Introducción: La fascitis necrotizante tiene origen polimicrobiano, se caracteriza por necrosis extensa acompañada de formación gaseosa en el tejido subcutáneo y fascia superficial. Objetivo: Describir el manejo terapéutico exitoso de dos casos afectos de fascitis necrotizante. Caso clínico: Dos pacientes tratados en el Hospital General Docente "Abel Santamaría Cuadrado", mujeres de la tercera y cuarta década de la vida, con área extensa de celulitis y necrosis de progreso rápido, necesidad de tratamiento quirúrgico y cultivos positivos de Pseudomona y Escherichia coli respectivamente, con repercusión clínica sistémica. Conclusiones: La fascitis necrotizante es una enfermedad de ascenso rápido y etiología variada, que pone en riesgo la vida del paciente, el diagnóstico debe sospecharse tempranamente ofreciendo intervención oportuna y agresiva, el manejo debe ser multidisciplinario(AU)

ABSTRACT Introduction: Necrotizing fasciitis has a polymicrobial origin. It is characterized by extensive necrosis accompanied by gas formation in the subcutaneous tissue and superficial fascia. Objective: To describe the successful therapeutic management of two cases with necrotizing fasciitis. Clinical case: Two patients treated at Abel Santamaría Cuadrado General Teaching Hospital, women at the third and fourth decades of life, with extensive area of cellulitis and rapidly progressing necrosis, need for surgical treatment and positive cultures of Pseudomonas and Escherichia coli, respectively, with systemic clinical repercussions. Conclusions: Necrotizing fasciitis is a disease of rapid progression and varied etiology, which puts the patient's life at risk; the diagnosis must be suspected early, offering timely and aggressive intervention, and management must be multidisciplinary(AU)

Influência de moléculas autoindutoras produzidas por Escherichia coli na formação de biofilme por Listeria monocytogenes / Influence of autoinducers produced by Escherichia coli on biofilm formation by Listeria monocytogenes

Listeria monocytogenes é um micro-organismo Gram-positivo que está comumente associado a doenças de origem alimentar. Possui a capacidade de sobreviver a condições adversas e de formar biofilme em diferentes superfícies abióticas, tornando-se um problema constante para a indústria de alimentos, pois pode comprometer a sanitização e aumentar o risco de contaminação pós-processamento. A formação de biofilme pode ser regulada por um mecanismo denominado quorum sensing, no qual ocorre intensa comunicação célula-célula, mediada por moléculas químicas, chamadas de autoindutoras. Pouco se sabe sobre a ocorrência de interação entre bactérias Gram- positivas e negativas na formação de biofilmes, sendo mais frequentes estudos entre bactérias do mesmo grupo. A fim de avaliar a ocorrência de interação entre Escherichia coli e L. monocytogenes (Lm), desenvolveu-se esta pesquisa com os seguintes objetivos: i) verificar a capacidade de Lm sorotipo 1/2a selvagem e sua mutante isogênica (ΔprfA ΔsigB) formar biofilme em presença de Escherichia coli, avaliando-se a importância dos reguladores de virulência, prfA e sigB, no processo; e ii) verificar a produção e interferência de moléculas autoindutoras de E. coli E2348/69 na formação de biofilme por Lm. Os ensaios de formação de biofilme foram realizados utilizando-se lâminas de aço-inoxidável AISI 304 #4 imersas em caldo infusão de cérebro e coração (BHI) e em meio pré-condicionado (MPC) por E. coli, com incubação a 25 ºC. Foram testadas duas concentrações iniciais de Lm (102 e 106 UFC.mL-1) e amostragens em diferentes tempos de incubação. Utilizou-se um método de quantificação indireto com coloração do biofilme por cristal violeta e posterior leitura da absorbância. Observou-se que Lm 1/2a selvagem e sua mutante isogênica (ΔprfA ΔsigB) são capaz de formar biofilme na presença de Escherichia coli e que uma maior quantidade de biofilme foi formada por Lm selvagem quando comparada à sua mutante, em meio não pré-condicionado (controle), indicando que prfA e sigB estão envolvidos no processo de formação de biofilme. Quando em MPC, o biofilme formado pela cepa selvagem foi menor que no meio controle (BHI), indicando que E. coli E2348/69, utilizada no pré-condicionamento do meio, produz moléculas capazes de interferir no processo de formação e na quantidade de biofilme formado por Lm; e para o biofilme formado pela cepa mutante, houve uma maior quantificação em MPC em comparação ao meio controle, o que sugere que os genes deletados possam estar envolvidos no reconhecimento das moléculas autoindutoras. Assim, os dados obtidos permitem concluir que há interação e interferência por parte de E. coli na formação de biofilme por Lm mediante produção de moléculas autoindutoras

Listeria monocytogenes (Lm) is a Gram-positive microorganism commonly associated with foodborne diseases. Due to its ability to survive under adverse environmental conditions and to form biofilm in different abiotic surfaces, this bacterium is a concern for the food industry, since it can compromise sanitation procedures and increase the risk of post-processing contamination. Biofilm formation can be regulated by a quorum sensing mechanism, in which there is intense cell-cell communication mediated by chemical molecules, called autoinducers. Little is known about the occurrence of interaction between Gram-positive and Gram-negative bacteria on biofilm formation. Thus, in order to evaluate the occurrence of interaction between Escherichia coli and Lm, this study was developed including the following objectives: i) to evaluate the ability of Lm 1/2a and its isogenic mutant strain (ΔprfAΔsigB) to form biofilm on the presence of Escherichia coli, assessing the importance of virulence regulators, prfA and sigB, in this process; and ii) to verify the production and interference autoinducers of E. coli E2348/69 on biofilm formation by Lm. Biofilm formation assays were conducted using stainless steel AISI 304 #4 immersed into broth brain heart infusion (BHI) and into preconditioned medium (MPC) by E. coli, following incubation at 25 °C. Lm at two initial concentrations (102 and 106 CFU.mL-1) and under different incubation time was tested. An indirect method for quantification of cells was applied, using crystal violet to color the biofilm, followed by optical density measurement. It was observed that Lm 1/2a and its isogenic mutant (ΔprfA ΔsigB) are able to form biofilm in the presence of Escherichia coli and a larger amount of biofilm was formed by wild strain Lm compared to its mutant, in a non-preconditioned medium (control), indicating that prfA and sigB are involved in biofilm formation. For MPC, the biofilm formation by the wild strain was lower than in the control (BHI), indicating that E. coli E2348/69, used in the preconditioned medium, produces molecules that can affect the formation process and the amount of biofilm formed by Lm; and in the biofilm formed by the mutant strain, there was a higher quantification of MPC compared to the control, suggesting that the deleted genes may be involved in recognition the of autoinducers. These results suggest that there is an interaction and interference of E. coli on biofilm formation by Lm due the production of autoinducers

Antibacterial activity of α-terpineol may induce morphostructural alterations in Escherichia coli

The antibacterial effect of α-terpineol from Cinnamomum longepaniculatum (Gamble) N. Chao leaf essential oils were studied with special reference to the mechanism of inhibiting the standard strain of Escherichia coli (CMCC (B) 44102) growth at ultrastructural level. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) and time-kill curves of α-terpineol were determined; Escherichia coli was treated with α-terpineol and observed under a transmission electron microscope. The MIC and MBC values of α-terpineol were all 0.78 µL/mL, and time-kill curves showed the concentration-dependent. Under the transmission electron microscopy (TEM), Escherichia coli exposed to MIC levels of α-terpineol exhibited decreased cell size and irregular cell shape, cell wall and cell membrane were ruptured, nucleus cytoplasm was reduced and nuclear area gathered aside. Results suggest that α-terpineol has excellent antibacterial activity and could induce morphological changes of Escherichia coli.

A comparative study on cell disruption methods for release of aspartase from E. coli K-12.

Applicability of different mechanical cell disruption techniques namely sonication, bead milling and French press for the release of aspartase from E. coli K-12 was compared. Various operating parameters of each technique were optimized to obtain maximum aspartase release. The efficiency of aspartase release and cell disruption by all the methods was also compared under optimal conditions. The maximum release of aspartase (98.22%) and maximum cell breakage (84.25%) was observed using French press, while 92% of aspartase release was obtained by both sonication and bead milling. The order of cell disruption constant (k) for aspartase release by these methods was French press > bead milling > sonication. Disruption of cells using French press also demonstrated maximum protein release (14.12 mg/mL). The crude enzyme preparations can be further used for purification and its applications.

Protective effect of some amino acids synthesized derivatives and their chelates on Escherichia coli under X-ray irradiation.

The protective effects of novel synthesized derivatives of some amino acids — nicotinyl-L-tyrosinate and nicotinyl-L-tryptophanate schiff bases and their Cu(II) and Mn(II) chelates on growth, survival and membrane-associated ATPase activity of E. coli under X-ray irradiation were investigated. The specific growth rate and survival of E. coli were decreased at 10, 20 and 30 Gy doses. However, as 30 Gy was found to be the most effective irradiation dose, it was chosen for studying the radio-protective properties of different compounds. These compounds could increase the bacterial cell protection against X-ray irradiation in concentration-dependent manner. They had a role in stimulation of synthesis or regulation of activity of metal-dependent enzymes, required for reversing the X-ray irradiation damage. The study may prove useful for further estimation of the effectiveness of different compounds as radio-protectors on bacteria and other cells, especially mammalian cells under X-ray irradiation.

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.

Caracterização funcional da proteína Cwc24p de Saccharomyces cerevisiae / Functional characterization of Cwc24p in Saccharomyces cerevisiae

Em eucariotos, a formação das subunidades ribossomais envolve múltiplos fatores, responsáveis pelas etapas de maturação dos rRNAs e por sua associação a proteínas ribossomais. A via de processamento de pré-rRNA é bastante complexa e inclui várias etapas de modificação de nucleotídeos e clivagens endo- e exonucleolíticas. As modificações de nucleotídeos são dirigidas por snoRNPs, formados por snoRNAs e proteínas, que são divididos em duas classes gerais, de box H/ACA (pseudouridilação) e de box C/O (metilação). Dentre os snoRNP de box C/D esta o U3, que embora apresente as sequências características e se associe a proteínas desse grupo de snoRNPs, não dirige metilações no rRNA, mas sim as clivagens iniciais no pré-rRNA 35S. O snoRNA U3 de Saccharomyces cerevisiae é codificado por dois genes que contêm introns, snR17A e snR17B. Embora a via de montagem do snoRNP U3 ainda não tenha sido determinada com precisão, sabe-se que algumas proteínas do core de box C/O ligam-se ao pré-snoRNA U3 co-transcricionalmente, afetando o splicing e o processamento da extremidade 3´ deste snoRNA...

Evaluation of a multiplex PCR method to detect enteroaggregative Escherichia coli

Enteroaggregative Escherichia coli (EAEC) has been implicated in sporadic diarrhea in children and adults and has been identified as the cause of several outbreaks worldwide. The HEp-2 test remains the gold standard for identification of this pathotype. A 60-65 MDa plasmid encodes the aggregative adherence fimbriae (AAF/I and AAF/II), a transcriptional activator (aggR gene), the enteroaggregative heat-stable enterotoxin EAST1 (astA gene) and a cytotoxin (Pet). The standard assay for EAEC is performed only in research laboratories, because it is expensive, labor intensive and time-consuming. The Polymerase Chain Reaction (PCR) offers the possibility of rapid diagnosis. In the current study, a multiplex PCR assay which checks aggR and astA genes was designed. Eigthy-eight E. Coli strains, isolated from children with acute diarrhea in Mendoza, Argentina, were characterized by the reference method (HEp-2 assay), and by aggR-astA PCR. A strong correlation between the presence of the specific marker aggR and the reference test was found. The astA gene had a similar distribution between aggregative and localized strains, indicating that this gene could not be considered as a marker of EAEC. We conclude that aggR may be used to identify EAEC, using the PCR method as a screening test.

Antigenotoxic and antimutagenic potential of an annatto pigment (norbixin) against oxidative stress

Carotenoids are 40-carbon molecules with conjugated double bonds, making them particularly effective for quenching free radicals. They have always been believed to possess anticancer properties, which could be due to their antioxidant potential. Norbixin is an unusual dicarboxylic water-soluble carotenoid present as a component in the pericarp of the seeds of Bixa orellana L. (from the Bixaceae family), a tropical shrub commonly found in Brazil. The main carotenoids present in these seeds, bixin and norbixin, form a coloring material, known as annatto, which is mainly used in the food industry. As annatto is only used as a coloring material, most studies of annatto pigments have focused on the determination of annatto levels in food. However, little attention has been given to the biological properties of bixin and norbixin. We evaluated the effect of norbixin on the response of Escherichia coli cells to DNA damage induced by UV radiation, hydrogen peroxide (H2O2) and superoxide anions (O2*-)) and found that norbixin protects the cells against these agents. Norbixin enhanced survival at least 10 times. The SOS induction by UVC was inhibited 2.3 times more when cells were grown in the presence of norbixin. We also found that norbixin has antimutagenic properties, with a maximum inhibition of H2O2-induced mutagenic activity of 87%, based on the Salmonella mutagenicity test

Effect of trace elements on surface hydrophobicity and adherence of Escherichia coli to uroepithelial cells.

Trace elements have significant effect on the physiology of bacteria. Variation in the concentration of trace elements may affect the expression of virulence by microorganisms. The effect of trace elements on hydrophobicity and adherence of E.coli to uroepithelial cells was studied. Increasing concentrations of Ca2+, Mg2+, Fe3+ and Zn2+ significantly decreased the surface hydrophobicity. Toxic trace elements like Co2+, Cu2+, Mn2+ and Ni2+ did not alter surface hydrophobicity. With regards to adherence of E.coli to uroepithelial cells, only Mg2+ had significant effect. Toxic trace elements decreased the rate of cell adherence. The pathogenic strains of E.coli showed higher surface hydrophobicity and better cell adherence compared to the nonpathogenic strains. There was good correlation between surface hydrophobicity and cell adherence at higher concentrations (0.1 to 0.2mM) of Fe2+ and Zn2+. The results indicated that trace elements can significantly affect surface hydrophobicity and adherence of E.coli to uroepithelial cells. Such effect may have a significant impact on the initial stages of bacterial infection.

Role of Tamm-Horsfall protein in the binding and in vivo phagocytosis of type 1 fimbriated Escherichia coli by mouse peritoneal macrophages

Tamm-Horsfall glycoprotein (THP) contains manno-oligosaccharides that are recognized by type 1 fimbriae (F1) of Escherichia coli. In the present study, we examined the in vivo phagocytic activity of mouse peritoneal macrophages after treatment of bacteria with THP. At low THP concentrations (12.5 æg/ml and 50 æg/ml) no significant difference was observed in the phagocytosis of E. coli F1+. However, at high THP concentrations (500 æg/ml and 1250 æg/ml) we obtained a reduction of bacterial phagocytosis by mouse peritoneal macrophages

Expression of the Mycobacterium bovis P36 gene in Mycobacterium smegmatis and the baculovirus/insect cell system

In the present study we evaluated different systems for the expression of mycobacterial antigen P36 secreted by Mycobacterium bovis. P36 was detected by Western blot using a specific antiserum. The P36 gene was initially expressed in E. coli, under the control of the T7 promoter, but severe proteolysis prevented its purification. We then tried to express P36 in M. smegmatis and insect cells. For M. smegmatis, we used three different plasmid vectors differing in copy number and in the presence of a promoter for expression of heterologous proteins. P36 was detected in the cell extract and culture supernatant in both expression systems and was recognized by sera from M. bovis-infected cattle. To compare the expression level and compartmentalization, the MPB70 antigen was also expressed. The highest production was reached in insect cell supernatants. In conclusion, M. smegmatis and especially the baculovirus expression system are good choices for the production of proteins from pathogenic mycobacteria for the development of mycobacterial vaccines and diagnostic reagents

Correlación de la citología de moco fecal con el coprocultivo en niños con diarrea aguda / Correlation of fecal mucus citology with coproculture in children with acute diarrhea

Se realizó un estudio retrospectivo en el Hospital Infantil Privado de la Ciudad de México del 1 de enero al 31 de diciembre de 1997, con el objetivo de determinar la utilidad de la citología de moco fecal en el diagnóstico de diarrea aguda en niños y su relación con el germen identificado en el coprocultivo. Se incluyeron 170 niños con diagnóstico de diarrea aguda en niños y su relación con el germen identificado en el coprocultivo. Se incluyeron 170 niños con diagnóstico de diarrea aguda con una mediana de edad entre 12 y 120 meses. A todos los pacientes se les realizó citología de moco fecal y coprocultivo, encontrándose 11 casos de citología de moco fecal positivo (6.5 por ciento) y 159 negativos (87.6 por ciento); en el coprocultivo el agente etiológico se identificó en 21 casos (12.3 por ciento), de los cuales ocho correspondieron a E. coli (4.7 por ciento), ocho a Salmonella (4.7 por ciento) y cinco a Shigella (2.9 por ciento). La relación de la citología de moco fecal y el agente identificado en el coprocultivo no fue significativo, ya que mostró p=0.13 mediante la prueba de Fisher

Incidencia de E coli en infecciones urinarias y su respuesta a los antimicrobianos (Experiencia del hospital San Gabriel 1994-1995) / Incidence of E. coli in urinary infection and antibacterial response (experience at San Gabriel Hospital)

Se realizo un estudio bacteriologico en muestras de orina de pacientes atendidos en el hospital San Gabriel durante el periodo comprendido entre mayo de 1994 a septiembre de 1995, cuyo diagnostico clinico fue ITU (infeccion del tracto urinario); de dichas muestras, 414 evidenciaron una bacteria como microorganismo causal. El estudio realizado, demuestra a E. coli como el agente causal mas frecuente en ITU (88.4 por ciento). Las pruebas de suceptibilidad a los distintos antimicrobianos demuestran una baja sensibilidad de E. coli a la ampicilina y al cotrimoxazol, antimicrobianos que frecuentemente se utilizan en nuestro medio para el tratamiento de ITU y cuyo estudio bacteriologico no siempre puede realizarse. Para la confirmacion estadistica de los resultados, se realizo la prueba Chi-cuadrado (X2), p< 0.05, cuyo resultado 13.08 indica que la elevada resistencia de E. coli a la ampicilina y al cotrimoxazol no se debe al azar, o a la casualidad sino mas bien a otros mecanismos que en el futuro deben investigarse. Cabe destacar la elevada sensibilidad de este microorganismo a antimicrobianos tales como: norfloxacina, acido pipemidico, nitrofuratoina, acido nalidixico, cefotaxima y gentamicina; lo cual concuerda con reportes internacionales previos

Manejo antimicrobiano en la peritonitis posdiálisis / Antimicrobial management of postdialysis peritonitis

Con el propósito de conocer la incidencia y el manejo antimicrobiano en la peritonitis posdiálisis, se estudiaron 358 procedimientos dialíticos, encontrando 37 casos de peritonitis con un porcentaje de 10.3, de los cuales 35 cumplían con los criterios de inclusión para el estudio, dividiéndose en dos grupos: grupo I formado por 19 pacientes en tratamiento con pefloxacina y grupo II integrado por 16 pacientes en tratamiento con ceftazidima. Obteniendo en el grupo I una remisión del cuadro en 89.5 por ciento y en el grupo II de 93.8 por ciento, no encontrando diferencia significativa (p=0.56) entre ambos antimicrobianos

Near-ultraviolet illumination inhibits the liquid holding recovery in Escherichia coli B

Liquid holing recovery (LHR) consist of an increase in the survival of UV-irradiated cells when they ar held under non-nutrient conditions before palting. In this study we investigated in E. coli B cells the effect of the growth inhibition induced by near UV (365 nm) illumination (growth delay, GD) before irradiation with UV-254 nm on the amplitude of LHR and the induction of an SOS function (filamentation) during the liquid holding period. Our results demonstrated that pre-illumination with near-UV inhibitis LHR and the induction of filamentation when the cells are incubated in nutrient medium. Moreover, this inhibition is due to GD, an effect caused by a photoproduct in the E. coli t-RNA, the 8-13 link