Factores asociados a infección por Acinetobacter baumannii en una Unidad de Cuidados Intensivos en Bogotá D.C.

INTRODUCCIÓN: Acinetobacter baumannii es un cocobacilo gram negativo, oportunista, de baja virulencia. En los últimos años, se ha convertido en responsable del aumento de la incidencia de infecciones en las Unidades de Cuidado Intensivo (UCI), que se caracterizan por multiresistencia a antibióticos de amplio espectro. METODOLOGÍA: Estudio de Casos y Controles Pareado, razón 1:4, en tres cohortes de brotes por A. baumannii 2006-2010 de un Hospital Universitario. Como medida de asociación se calculó el Odd Ratio con una confiabilidad del 95%, utilizando regresión logística condicional. RESULTADOS: Se identificaron 3 brotes en el periodo 2006-2010, de los cuales se obtuvo una muestra de 14 casos y 56 controles. En el análisis multivariado se encontró asociación estadísticamente significativa entre la infección/colonización por A. baumannii y el presentar algún estado de inmunosupresión (OR=15.45; IC95%=1.12-212.44) y el tener catéter venoso central en un tiempo superior a diez días (OR=13.74; IC95%=1.25-151.44). No se encontró asociación estadísticamente significativa entre infección/colonización y mortalidad. De 14 casos, 13 presentaron aislamientos de multiresistentes, 9 son de origen respiratorio, 2 hemocultivos y 3 de origen abdominal. La mortalidad en los casos no está asociada a procesos de inmunosupresión, bacteremias e infecciones/colonizaciones respiratorias. CONCLUSIONES: La infección/colonización por A. baumannii se asoció a estado de inmunosupresión del paciente y el tener catéter venoso central por más de 10 días, que se correlaciona con la intervención invasiva, frecuente en las Unidades de Cuidados Intensivos. No fue posible establecer diferenciación clara entre infección y colonización, y su asociación con la mortalidad de los pacientes.

Actividad antibacteriana del aceite esencial de la conobea scopariodes frente a cinco cepas bacterianas de interés clínico en Colombia

En Colombia el manejo de pacientes en los diferentes servicios hospitalarios han presentado inconvenientes en el combate de infecciones por bacterias y la resistencia de las mismas; el Staphylococcus aureus Escherichia coli y Pseudomonas aeruginosa, han demostrado evolución en la creación de generaciones resistentes y también han participado junto con la Salmonella y el B.cereus en brotes por ETAS como principales microorganismos causales. En el presente estudio se analizó el aceite esencial de la Conobea scoparioides para evaluar su actividad frente a cinco cepas bacterianas. Se obtuvo el AE y se prepararon las bacterias aplicándose pruebas de sensibilidad y no paramétricas para determinar el porcentaje de inhibición, la evaluación de la MIC y comparar la efectividad del aceite vs la estreptomicina. El aceite esencial presentó actividad principalmente contra el B. cereus con el mayor % de inhibición y una MIC de 3.2 ug/ml, caso diferente presentó P. aeruginosa con un % de crecimiento por encima del 50% presentando una MIC de 16.7 ug/ml. Finalmente podemos concluir que se presentó mayor actividad frente a bacterias gram positivas como el caso del B. cereus que en gram negativas con MIC bajas. Estos resultados permite comparar la actividad de la conobea con estudios recientes bajo la misma modalidad que permiten identificar nuevas plantas con actividad biológica y percibir que la conobea es efectiva en mayor proporción frente a bacterias gram positivas.

Desenlaces de las infecciones respiratorias en la unidad de cuidado intensivo de la fundación neumologica colombiana

Las infecciones asociadas a ventilación mecánica (VM) son frecuentes en la unidad de cuidado intensivo (UCI). Existen dos infecciones: neumonía (NAV) y traqueobronquitis (TAV). NAV genera impacto negativo en los desenlaces de los pacientes al aumentar la morbilidad, mortalidad y los tiempos en UCI y VM, pero no se conoce el impacto de TAV. El objetivo de este estudio fue identificar si hay diferencias entre NAV y TAV. Materiales y métodos: Se realizó un estudio de cohortes entre 2009 y 2013 en la UCI de la Fundación Neumológica Colombiana. De los pacientes con NAV y TAV se obtuvieron datos demográficos, epidemiológicos, microbiológicos y desenlaces como tiempos de estancia en UCI, VM y de hospitalización y mortalidad. Se compararon estadísticamente mediante t de Student y Chi2 para datos normales y prueba de Mann-Whitney para datos no normales. Resultados: Los pacientes con NAV y TAV fueron similares en la condición de ingreso a UCI. Al diagnóstico de la infección hubo diferencias significativas entre grupos en la oxigenación y tiempo de estancia hospitalaria, en UCI y VM. La microbiología fue con predominio de gérmenes Gram negativos y presencia de multirresistencia en el 52.5% de casos, sin diferencias significativas entre grupos. En los desenlaces, se observó diferencias en los tiempos totales de estancia en UCI, hospitalización y VM, pero sin diferencia en ellos después del diagnóstico. No hubo diferencias significativas en mortalidad. Conclusiones: NAV y TAV son similares en el impacto sobre la evolución de los pacientes en cuanto a morbilidad, estancias y mortalidad.

Perfil microbiológico, prevalencia de resistencia antibiótica y patrones de susceptibilidad en infección urinaria en una población pediátrica

Introducción: El incremento de la resistencia antibiótica se considera un problema de salud pública con consecuencias clínicas y económicas, por lo tanto se determinará la prevalencia de resistencia antibiótica en Infección del Tracto Urinario (ITU, el perfil microbiológico y los patrones de susceptibilidad en una población pediátrica atendida en la Fundación Cardioinfantil. Materiales y métodos: Estudio observacional de corte transversal, retrospectivo, entre 1 mes a 18 años de edad, con diagnóstico de ITU comunitaria atendidos entre Enero de 2011 y Diciembre de 2013. Se excluyeron pacientes con dispositivos en la vía urinaria, instrumentación quirúrgica previa, trayectos fistulosos entre la vía urinaria y sistema digestivo, ITU luego de 48 horas de hospitalización y recaída clínica en tratamiento. Se estableció la prevalencia de ITU resistente y se realizó un análisis descriptivo de la información. Resultados: Se evaluaron 385 registros clínicos, con una mediana de 1.08 años (RIQ 0.8 – 4.08), el 73.5% eran niñas. La fiebre predominó (76.5%), seguido de emesis (32.0%), disuria (23.7%) y dolor abdominal (23.1%). El uropatógeno más frecuente fue E.coli (75%), seguido de Proteus mirabilis (8.5%) y Klebsiella spp. (8.3%). La Ampicilina, el Trimetropim sulfametoxazol, la Ampicilina sulbactam y el ácido nalidixico tuvieron mayor tasa de resistencia. La prevalencia de BLEE fue 5.2% y AmpC 3.9%. La prevalencia de resistencia antimicrobiana fue de 11.9%. Conclusiones: La E.coli es el uropatogeno más frecuentemente aislado en ITU, con resistencia a la ampicilina en 60.2%, cefalosporinas de primera generación en 15.5%, trimetropin sulfametoxazol en 43.9%, cefepime 4.8%. La prevalencia de resistencia antimicrobiana fue de 11.9%.

The use of bioluminescence for monitoring in planta growth dynamics of a Pseudomonas syringae plant pathogen

The use of bioluminescence was evaluated as a tool to study Pseudomonas syringae population dynamics in susceptible and resistant plant environments. Plasmid pGLITE, containing the luxCDABE genes from Photorhabdus luminescens, was introduced into Pseudomonas syringae pv. phaseolicola race 7 strain 1449B, a Gram-negative pathogen of bean (Phaseolus vulgaris). Bacteria recovered from plant tissue over a five-day period were enumerated by counting numbers of colony forming units and by measurement of bioluminescence. Direct measurement of bioluminescence from leaf disc homogenates consistently reflected bacterial growth as determined by viable counting, but also detected subtle effects of the plant resistance response on bacterial viability. This bioluminescence procedure enables real time measurement of bacterial metabolism and population dynamics in planta, obviates the need to carry out labour intensive and time consuming traditional enumeration techniques and provides a sensitive assay for studying plant effects on bacterial cells.

Detection and enumeration of sulphate-reducing bacteria in estuarine sediments by competitive PCR

The distribution of sulphate-reducing bacteria (SRB) in the sediments of the Colne River estuary, Essex, UK covering different saline concentrations of sediment porewater was investigated by the use of quantitative competitive PCR. Here, we show that a new PCR primer set and a new quantitative method using PCR are useful tools for the detection and the enumeration of SRB in natural environments. A PCR primer set selective for the dissimilatory sulphite reductase gene (dsr) of SRB was designed. PCR amplification using the single set of dsr-specific primers resulted in PCR products of the expected size from all 27 SRB strains tested, including Gram-negative and positive species. Sixty clones derived from sediment DNA using the primers were sequenced and all were closely related with the predicted dsr of SRB. These results indicate that PCR using the newly designed primer set are useful for the selective detection of SRB from a natural sample. This primer set was used to estimate cell numbers by dsr selective competitive PCR using a competitor, which was about 20% shorter than the targeted region of dsr. This procedure was applied to sediment samples from the River Colne estuary, Essex, UK together with simultaneous measurement of in situ rates of sulphate reduction. High densities of SRB ranging from 0.2 - 5.7 × 108 cells ml-1 wet sediment were estimated by the competitive PCR assuming that all SRB have a single copy of dsr. Using these estimates cell specific sulphate reduction rates of 10-17 to 10-15 mol of SO42- cell-1 day-1 were calculated, which is within the range of, or lower than, those previously reported for pure cultures of SRB. Our results show that the newly developed competitive PCR technique targeted to dsr is a powerful tool for rapid and reproducible estimation of SRB numbers in situ and is superior to the use of culture-dependent techniques.

Anaerofustis stercorihominis gen. nov., sp nov., from human faeces

Phenotypic and phylogenetic studies were performed on an unidentified Gram-positive, strictly anaerobic, non-spore-forming, rod-shaped bacterium isolated from human feces. The organism was catalase-negative, resistant to 20% bile, produced acetic and butyric acids as end products of glucose metabolism, and possessed a G + C content of approximately 70 mol %. Comparative 16S rRNA gene sequencing demonstrated that the unidentified bacterium was a member of the Clostridium sub-phylum of the Gram-positive bacteria, and formed a loose association with rRNA cluster XV. Sequence divergence values of 12% or greater were observed between the unidentified bacterium and all other recognized species within this and related rRNA clusters. Treeing analysis showed the unknown anaerobe formed a deep line branching near to the base of rRNA cluster XV and phylogenetically represents a hitherto unknown taxon, distinct from Acetobacterium, Eubacterium sensu stricto, Pseudoramibacter and other related organisms. Based on both phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium from feces be classified in a new genus Anaerofustis, as Anaerofustis stercorihominis sp. nov. The type strain of Anaerofustis stercorihominis is ATCC BAA-858(T) = CCUG 47767(T). (C) 2003 Elsevier Ltd. All rights reserved.

Pseudomonas syringae pv. phaseolicola: from ‘has bean’ to supermodel

Pseudomonas syringae pv. phaseolicola causes halo blight of the common bean, Phaseolus vulgaris, worldwide and remains difficult to control. Races of the pathogen cause either disease symptoms or a resistant hypersensitive response on a series of differentially reacting bean cultivars. The molecular genetics of the interaction between P. syringae pv. phaseolicola and bean, and the evolution of bacterial virulence, have been investigated in depth and this research has led to important discoveries in the field of plant-microbe interactions. In this review, we discuss several of the areas of study that chart the rise of P. syringae pv. phaseolicola from a common pathogen of bean plants to a molecular plant-pathogen supermodel bacterium. Taxonomy: Bacteria; Proteobacteria, gamma subdivision; order Pseudomonadales; family Pseudomonadaceae; genus Pseudomonas; species Pseudomonas syringae; Genomospecies 2; pathogenic variety phaseolicola. Microbiological properties: Gram-negative, aerobic, motile, rod-shaped, 1.5 µm long, 0.7-1.2 µm in diameter, at least one polar flagellum, optimal temperatures for growth of 25-30 °C, oxidase negative, arginine dihydrolase negative, levan positive and elicits the hypersensitive response on tobacco. Host range: Major bacterial disease of common bean (Phaseolus vulgaris) in temperate regions and above medium altitudes in the tropics. Natural infections have been recorded on several other legume species, including all members of the tribe Phaseoleae with the exception of Desmodium spp. and Pisum sativum. Disease symptoms: Water-soaked lesions on leaves, pods, stems or petioles, that quickly develop greenish-yellow haloes on leaves at temperatures of less than 23 °C. Infected seeds may be symptomless, or have wrinkled or buttery-yellow patches on the seed coat. Seedling infection is recognized by general chlorosis, stunting and distortion of growth. Epidemiology: Seed borne and disseminated from exudation by water-splash and wind occurring during rainfall. Bacteria invade through wounds and natural openings (notably stomata). Weedy and cultivated alternative hosts may also harbour the bacterium. Disease control: Some measure of control is achieved with copper formulations and streptomycin. Pathogen-free seed and resistant cultivars are recommended. Useful websites: Pseudomonas-plant interaction http://www.pseudomonas-syringae.org/; PseudoDB http://xbase.bham.ac.uk/pseudodb/; Plant Associated and Environmental Microbes Database (PAMDB) http://genome.ppws.vt.edu/cgi-bin/MLST/home.pl; PseudoMLSA Database http://www.uib.es/microbiologiaBD/Welcome.html.

Screening for endophytic nitrogen-fixing bacteria in Brazilian sugar cane varieties used in organic farming and description of Stenotrophomonas pavanii sp. nov.

A Gram-negative, rod-shaped, non-spore-forming and nitrogen-fixing bacterium, designated ICB 89(T), was isolated from stems of a Brazilian sugar cane variety widely used in organic farming. 16S rRNA gene sequence analysis revealed that strain ICB 89(T) belonged to the genus Stenotrophomonas and was most closely related to Stenotrophomonas maltophilia LMG 958(T), Stenotrophomonas rhizophila LMG 22075(T), Stenotrophomonas nitritireducens L2(T), [Pseudomonas] geniculata ATCC 19374(T), [Pseudomonas] hibiscicola ATCC 19867(T) and [Pseudomonas] beteli ATCC 19861(T). DNA-DNA hybridization together with chemotaxonomic data and biochemical characteristics allowed the differentiation of strain ICB 89(T) from its nearest phylogenetic neighbours. Therefore, strain ICB 89(T) represents a novel species, for which the name Stenotrophomonas pavanii sp. nov. is proposed. The type strain is ICB 89(T) (=CBMAI 564(T) =LMG 25348(T)).

Resposta de Chromobacterium Violaceum cultivada em alta concentração de ferro

The Chromobacterium violaceum is a β-proteobacterium Gram-negative widely found in tropical and subtropical regions, whose genome was sequenced in 2003 showing great metabolic versatility and biotechnological and pharmaceutical potential. Given the large number of ORFs related to iron metabolism described in the genome of C. violaceum, the importance of this metal for various biological processes and due to lack of data about the consequences of excess of iron in free-living organisms, it is important to study the response mechanism of this bacterium in a culture filled with iron. Previous work showed that C. violaceum is resistant to high concentrations of this metal, but has not yet been described the mechanism which is used to this survival. Thus, to elucidate the response of C. violaceum cultured in high concentrations of iron and expecting to obtain candidate genes for use in bioremediation processes, this study used a shotgun proteomics approach and systems biology to assess the response of C. violaceum grown in the presence and absence of 9 mM of iron. The analysis identified 531 proteins, being 71 exclusively expressed by the bacteria grown in the presence of the metal and 100 just in the control condition. The increase in expression of proteins related to the TCA cycle possibly represents a metabolic reprogramming of the bacteria caused by high concentration of iron in the medium. Moreover, we observed an increase in the activity assay of superoxide dismutase and catalase as well as in Total Antioxidant Activity assay, suggesting that the metal is inducing oxidative stress in C. violaceum that increases the levels of violacein and antioxidant enzymes to better adapt to the emerging conditions. Are also part of the adaptive response changes in expression of proteins related to transport, including iron, as well as an increased expression of proteins related to chemotaxis response, which would lead the bacteria to change the direction of its movement away from the metal. Systems Biology results, also suggest a metabolic reprogramming with mechanisms coordinated by bottleneck proteins involved in transcription (GreA), energy metabolism (Rpe and TpiA) and methylation (AhcY)

Occurrence of yeasts, pseudomonads and enteric bacteria in the oral cavity of patients undergoing head and neck radiotherapy

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

Essential Oils Against Foodborne Pathogens and Spoilage Bacteria in Minced Meat

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

Atividade antimicrobiana in vitro da cefpiroma em comparação com outros beta-lactâmicos de amplo espectro contra 804 amostras clínicas de nove hospitais brasileiros

OBJETIVO: Avaliar a atividade in vitro da cefalosporina de quarta geração, cefpiroma em comparação com ceftazidima, ceftriaxona, cefotaxima e imipenem em um estudo multicêntrico envolvendo nove hospitais de seis cidades em quatro estados. MATERIAL E MÉTODOS: Foram estudadas 804 amostras clínicas isoladas em pacientes internados em unidades de terapia intensiva ou unidades de oncohematologia. As amostras foram coletadas no período de junho a novembro de 1995, isto é, antes da cefpiroma estar disponível comercialmente no Brasil, e testadas através do método de microdiluição em placas conforme descrito pelo National Committee for Clinical Laboratory Standards (NCCLS). Todas as amostras resistentes à cefpiroma foram retestadas utilizando-se o E-test. RESULTADOS: Contra as amostras de enterobactérias (n= 344), a cefpiroma apresentou atividade de 2 a 32 vezes superior àquela apresentada pelas cefalosporinas de terceira geração (CTGs) e semelhante àquela apresentada pelo imipenem. As porcentagens de enterobactérias sensíveis foram: 88% para a cefpiroma, 69% para as CTGs e 96% para o imipenem. O espectro de ação da cefpiroma foi maior ou igual ao do imipenem contra as espécies Citrobacter freundii, E. aerogenes, Morganella morganii e Serratia marcescens. Contra Acinetobacter sp. (n=77), a cefpiroma foi ligeiramente mais ativa que a ceftazidima, porém as porcentagens de resistência foram muito altas para esses compostos (84% e 88% respectivamente). As atividades da cefpiroma, ceftazidima e imipenem foram semelhantes contra Pseudomonas aeruginosa (n=128), com MIC50/porcentagem de sensibilidade de 8/59%, 8/62% e 4/62% respectivamente. Contra bactérias aeróbias gram-positivas, a cefpiroma foi de 4 a 16 vezes mais ativa que as CTGs. Contra S. epidermidis e outras espécies de estafilococos coagulase-negativos a cefpiroma foi ligeiramente superior ao imipenem, porém, contra as outras espécies de bactérias gram-positivas avaliadas, o imipenem apresentou atividade um pouco superior. CONCLUSÃO: Os resultados desse estudo sugerem que, no Brasil, a cefpiroma apresenta espectro de ação superior ao das CTGs contra bactérias gram-negativas (Enterobacteriaceae e não-fermentadares) e gram-positivas e semelhante ao do imipenem contra algumas espécies de enterobactérias e contra P. aeruginosa.

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.

Avaliacao da atividade da nova cefalosporina de quarta geracao cefpiroma contra amostras clinicas isoladas em unidades de terapia intensiva e unidades de oncoematologia de varios hospitais brasileiros

Objective: To evaluate the in vitro activity of the fourth-generation cephalosporin cefpirome in comparison to that of ceftazidime, ceftriaxone, cefotaxime and imipenem in a multicenter study involving nine hospitals from six cities (four states). Material and methods: A total of 804 isolates from patients hospitalized in either intensive care units or Oncology/Hematology units was evaluated. The isolates were collected between June and November of 1995, i.e. before cefpirome became commercially available in Brazil, and susceptibility tested by broth microdilution following the NCCLS procedures. All isolates resistant to cefpirome were retested by B-test. Results: Against Enterobacteriaceae (n = 344), cefpirome demonstrated an activity 2 to 32-fold higher than that of the third-generation cephalosporins (TGCs) and similar to that of imipenem. The percentages of Enterobacteriaceae susceptible were: 88%, 69% and 96% for cefpirome, TGCs and imipenem, respectively, The cefpirome spectrum were greater or equal to that of imipenem against Citrobacter freundii, Enterobacter aerogenes, Morganellao morganii and Serratia marcescens. Against Acinetobacter sp. (n = 77), cefpirome was slightly more active than ceftazidime; however, the percentages of isolates resistant to these compounds were high (84% and 88%, respectively). The activities of cefpirome, ceftazidime and imipenem were very similar against P. aeruginosa isolates (n = 128), with MIC50 (μg/ml) percent susceptible of 8/59%, 8/62% and 4/62% respectively, Against aerobic gram-positive bacteria, the cefpirome activity was 4 to 16-fold higher than that of TGCs but 2 to 8-fold lower than that of imipenem. Conclusion: The results of our study suggest that, in Brazil, cefpirome has a spectrum of activity which is higher than that of the TGCs against aerobic gram-negative (Enterobacteriaceae and non-Enterobacteriaceae) and gram-positive bacteria and similar to that of imipenem against some Enterobacteriaceae species and P. aeruginosa.