Hoeflea prorocentri sp. nov., isolated from a culture of the marine dinoflagellate Prorocentrum mexicanum PM01.

A Gram-stain negative, aerobic, rod-shaped, non-motile, yellow-pigmented and non-spore-forming bacterial strain, designated PM5-8T, was isolated from a culture of a marine toxigenic dinoflagellate Prorocentrum mexicanum PM01. Strain PM5-8T grew at 15-35 °C (optimum, 25-30 °C) and pH 6-11 (optimum, 7.5-8). Cells required at least 1.5% (w/v) NaCl for growth, and can tolerate up to 7.0% with the optimum of 4%. Phylogenetic analysis based on 16S rRNA gene sequence revealed that the strain PM5-8T is closely related to members of the genus Hoeflea, with high sequence similarities with Hoeflea halophila JG120-1T (97.06%) and Hoeflea alexandrii AM1V30T (97.01%). DNA-DNA hybridization values between the isolate and other type strains of recognized species of the genus Hoeflea were between 11.8 and 25.2%, which is far below the value of 70% threshold for species delineation. The DNA G + C content was 50.3 mol%. The predominant cellular fatty acids of the strain were identified as summed feature 8 (C16:1 ω7c and/or C16:1 ω6c; 51.5%), C18:1 ω7c 11-methyl (20.7%), C16:0 (17.2%) and C18:0 (5.7%). The major respiratory quinone was Q-10. Polar lipids profiles contained phosphatidylcholine, phosphatidylglycerol, sulfoquinovosyl diacylglycerol, phosphatidylmono- methylethanolamine, phosphatidylethanolamine and four unidentified lipids. On the basis of the polyphasic taxonomic data presented, strain PM5-8T (= CCTCC AB 2016294T = KCTC 62490T) represents a novel species of the genus Hoeflea, for which the name Hoeflea prorocentri sp. nov. is proposed.

Sepsis neonatal tardía nosocomial en una unidad de terapia intensiva: agentes etiológicos y localización más frecuente / Late onset neonatal sepsis in an intensive care neonatal unit: etiological agents and most frequent location

Resumen Introducción: La sepsis neonatal nosocomial (SNN) es una entidad frecuente en las unidades de cuidados intensivos, donde causa una gran morbimortalidad. La ubicación más frecuente es bacteriemia, seguido de neumonía asociada a ventilador mecánico y vía urinaria. Objetivo: Conocer la etiología y localización más frecuente de la infección en el SNN. Población, Material y Métodos: Estudio retrospectivo, de prevalencias de enero a diciembre de 2015, realizado en la Unidad de Cuidados Intensivos Neonatal de un hospital de alta complejidad. Fueron incluidos todos los neonatos. Resultados: Se incluyeron 70 pacientes, se analizaron 88 episodios de SNN. La localización más frecuente fue sangre 40% de los casos, seguido de orina y aspirado traqueal en 25% respectivamente. Los microorganismos más frecuentemente aislados fueron Staphylococcus de diferentes tipos, seguido de Acinetobacter baumannii multi-resistente. La afectación del SNC fue de 32%. La mortalidad fue de 34%, elevándose a 50% ante un segundo episodio de SNN. La terapia empírica de elección fue vancomicina y carbapenem, ajustándose a antibiograma. Conclusiones: La infección más frecuente fue la bacteremia, principalmente por Staphylococcus resistentes a meticilina. La afectación del SNC fue elevada, lo mismo que la mortalidad.

Introduction: Nosocomial neonatal sepsis (NNS) is a frequent entity in intensive care units, causing great morbidity and mortality. The most frequent site is blood, followed by lungs and urine. Objective: To know the etiology and most frequent localization of infection in the NNS. Population, Material and Methods: Cross sectional study, from January to December 2015, performed in a teaching hospital. All newborns infants were included. Results: 70 patients were included, 88 episodes of NNS were analyzed. The most frequent localization was bacteremia in 40% of cases, followed by urinary tract infection and VAP in 25% respectively. The bacteria most frequently isolated were staphylococci of different types, followed by multiresistant Acinetobacter. The CNS involvement was 32%. Mortality was 34%, rising up to 50% with a second episode of NNS. The empirical therapy of choice was vancomycin and carbapenem, adjusting to antibiogram. Conclusions: The most frequent infection was bacteremia, mainly by staphylococci resistant to methicillin. CNS involvement was elevated, as well as mortality.

Epidemiología de las infecciones urinarias asociadas a catéter y no asociadas a catéter en un hospital universitario de tercer nivel / Nosocomial urinary tract infection: an analysis beyond urinary catheterization

Resumen Introducción: Las infecciones urinarias asociadas a la atención de la salud (ITU-AAS) representan un importante problema sanitario, siendo poco conocidas sus características cuando no están asociadas a cateterización urinaria u ocurren fuera de unidades de cuidados intensivos (UCI). Objetivos: Determinar las características de los pacientes con ITU-AAS, etiología y susceptibilidad antimicrobiana de las mismas, tanto asociadas a catéter (ITU-C) como no asociadas a catéter (ITU-noC), en UCI y en sala general. Materiales y Métodos: Se realizó un estudio analítico retrospectivo de corte transversal entre 2009 y 2013 en un hospital universitario de tercer nivel. Se identificaron todos los episodios de ITU-AAS, diferenciándolas en ITU-C e ITU-noC. Resultados: Se incluyeron 253 episodios de ITU-AAS, siendo más frecuentes las ITU-C (60,9%) respecto a ITU-noC. Un 37,4% de ITU-noC y 59,7% de ITU-C ocurrieron en UCI. Los microorganismos aislados más frecuentemente fueron Escherichia coli, Klebsiella pneumoniae y Enterococcus sp. El 19% de los bacilos gramnegativos fueron productores de β-lactamasa de espectro extendido, siendo su frecuencia similar en ambos grupos. Conclusión: Las co-morbilidades de los pacientes con ITU-AAS, los agentes etiológicos responsables y sus correspondientes espectros de sensibilidad, fueron similares en los grupos de ITU-C e ITU-noC, tanto en sala general como en UCI.

Introduction: Nosocomially acquired urinary tract infections (NAUTI) represent an important public health issue, but its characteristics when they are not catheter associated (CA-UTI) or when they take place outside intensive care units (ICU) are poorly understood. Objectives: To determine the patients' characteristics, etiology and antimicrobial susceptibility of NAUTI, both CA-UTI and no CA-UTI, in general ward and ICU. Methods: We conducted a retrospective analytic cross-sectional study, between 2009 and 2013, in a third level universitary hospital. All NAUTI episodes were identified, classifying them as CA-UTI and no CA-UTI. Results: We included 253 episodes of NAUTI, being CA-UTI (60,9%) more frequent than no CA-UTI. A 37,4% of no CA-UTI and 59,7% of CA-UTI were identified in ICU. The most frequently isolated microorganisms were Escherichia coli, Klebsiella pneumoniae and Enterococcus sp. A 19% of extended spectrum betalactamase producing gram negative bacilli were found, without differences between groups. Conclusion: Patients's comorbidities, microorganisms associated to NAUTI and its antimicrobial susceptibility were similar in CA-UTI and no CA-UTI, as in general ward and ICU.

Evaluación de test rápidos y diseño de una estrategia para la detección y caracterización de carbapenemasas en cepas de bacilos gramnegativos / Test evaluation and strategy proposal to detect and to characterize carbapenemase-producing gram negative bacilli

Resumen Introducción: La detección de bacilos gramnegativos productores de carbapenemasas es compleja, existiendo actualmente varios test disponibles. La confirmación mediante la caracterización molecular de la enzima no está disponible en todos los laboratorios del país. Objetivo: Plantear una estrategia rápida, eficiente y sencilla para la detección y confirmación de carbapenemasas en cepas de bacilos gramnegativos. Material y Métodos: Se utilizaron 39 aislados productores y ocho no productores de carbapenemasas para evaluar los test fenotípicos Carba NP, CarbAcineto NP, Blue-Carba y validar el test molecular Xpert® Carba-R directo de la colonia en comparación con RPC convencional. Resultados: La sensibilidad para Carba NP, CarbAcineto NP y Blue-Carba fue de 79,5; 87,2 y 84,6%, respectivamente; mientras que la especificidad fue de 100; 100 y 87,5%, respectivamente. La concordancia entre RPC convencional y Xpert® Carba-R fue de 100%. El límite de detección para Xpert® Carba-R fue diferente según el tipo de carbapenemasa: 40,8 ufc/reacción par KPC y NDM y 30,6 ufc/reacción para VIM. Discusión: En aislados con susceptibilidad disminuida a carbapenémicos se propone realizar un tamizaje con CarbAcineto NP, para luego caracterizar la carbapenemasa con Xpert® Carba-R y adoptar las medidas de contención específica: para cada caso.

Introduction: The detection of carbapenemase-producing gram negative bacilli is complicated, because there are available multiple options of test. The confirmation of the enzyme by molecular characterization is not available in all laboratories in our country. Objective: To propose a fast, efficient and simple strategy to detect and confirm CPB. Materials and Methods: 39 CPB isolates and 8 non-producing were used to evaluate the phenotypic test Carba NP, CarbAcineto NP and Blue-Carba, validating the test Xpert® Carba-R, to be used directly with bacterial colonies with conventional PCR. Results: The sensitivity of Carba NP, CarbAcineto NP and Blue-Carba was 79,5; 87,2 y 84,6%, respectively; and specificity was 79.5; 87.2 and 84.6%, respectively. The limit of detection of Xpert® Carba-R was different for each carbapenemasa: 40.8 ufc/reaction to KPC and NDM and 30.6 ufc/reaction to VIM. Discussion: On isolates with decreased susceptibility to carbapenems we propose to use as screening the test CarbAcineto NP, follow by Xpert®Carba-R to characterize the carbapenemase and adopt specific infection control measures.

Effect of edible coatings with essential oils on the quality of red raspberries over shelf-life.

BACKGROUND: The objective of the present work was to develop strategies for increasing the shelf-life of red raspberries (Rubus idaeus L.), by preventing microorganism growth. RESULTS: Fruits coated with alginate plus lemon essential oil (0.2%) or orange essential oil (0.1%) after 15 days of storage had less red skin than the remaining samples. The less red color verified in these samples was also coincident with the lower concentration of anthocyanins at the end of the experiment as well as the lower capacity for scavenging ABTS free radicals or quenching singlet oxygen. Cyanidin and pelargonidin glucosides were found in raspberries fruits. The edible coatings supplemented with the essential oil of orange either at 0.1% or 0.2% were very efficient for controlling yeast and mold growth after 15 days of storage. To control the development of aerobic mesophilic bacteria the use of essential oil of lemon 0.2% and essential oil of orange 0.1% were the most efficient. CONCLUSION: The application of the film improved post-harvest quality of raspberry, since the addition of essential oils of citrus films promoted to the inhibitory effect of fungi and bacteria growth after 15 days of storage, without changing quality parameters. © 2016 Society of Chemical Industry.

Espondilodiscitis: experiencia clínica en un hospital general de Chile / Spondylodiscitis: clinical experience in a Chilean general hospital

Introducción: La espondilodiscitis (ED) implica prolongados períodos de hospitalización, de latencia diagnóstica y riesgo de complicaciones a largo plazo. No existen publicaciones recientes en Chile al respecto. Objetivos: Caracterizar un grupo de pacientes con ED. Pacientes y Métodos: Serie clínica, que incluyó pacientes en un período de ocho años. Resultados: 37 pacientes, 37,8% mujeres y 62,2% hombres, con promedio etario 66,8 años; 64,9% adultos mayores, 35,1% diabéticos y 21,6% con co-morbilidad urológica. Los principales síntomas fueron dolor y fiebre. 89,2% tuvo elevación de VHS. 86,5% contó con resonancia magnética, que siempre fue confirmatoria, siendo la columna lumbar la localización más frecuente (43,2%). Se identificó etiología en 28/37 pacientes: en 71,4% cocáceas grampositivas (Staphylococcus aureus predominantemente), sólo en 10,7% M. tuberculosis. Staphylococcus aureus estuvo asociado a co-morbilidades médicas en forma significativa (p < 0,05) y el grupo de bacilos gramnegativos a historia hepatobiliar y/o intestinal (p < 0,05). El método de mayor rendimiento fue el cultivo obtenido por punción quirúrgica. El tratamiento antimicrobiano fue indicado en promedio por 63,8 días (IQR 53-72), con reacciones adversas en 18,9%. La estadía hospitalaria fue 38,9 días promedio, no existiendo fallecidos durante este período. 18,9% presentó secuelas motoras. Discusión: La mayoría de pacientes con ED correspondió a adultos mayores, siendo S. aureus la principal etiología. Hubo una baja frecuencia de M. tuberculosis. Resultó considerable la magnitud de efectos adversos asociados a la terapia antimicrobiana y las complicaciones neurológicas.

Background: Spondylodiscitis (SD) involves long periods of hospitalization, diagnostic latency and risk of long-term complications. No updated series are available in Chile and a change in demographic features and etiology is suspected. Aim: To characterize a group of patients with SD. Patients and Methods: Clinical series including patients over an 8 year period. Results: We identified 37 patients; 37.8% women and 62.2% men (mean age 66.8 years); 64.9% were elderly; 35.1% had diabetes and 21.6% urological comorbidity. Main symptoms were pain and fever. Erythrocyte sedimentation rate was elevated in 89.2%, and 86.5% patients had MRI, which was always confirmatory. Lumbar spine was the most common site of infection (43.2%). Etiology was identified in 28/37 patients: 71.4% yielded grampositive cocci (Staphylococcus aureus predominantly), Mycobacterium tuberculosis was identified in only 10.7%. Staphylococcus aureus was associated to medical comorbidities (p < 0,05) and gramnegative bacilli to hepatobiliar or intestinal symptoms (p < 0,05). Culture obtained by a surgical procedure had the highest yield. The average duration of antibiotic therapy was 63.8 days (IQR 53-72). Treatment-related side effects were detected in 18.9% of patients. The average hospital stay was 38.9 days. No deaths occurred during hospitalization. Motor sequelae were present in 18.9% of this series. Discussion: Most patients with SD were older adults. Staphylococcus aureus was predominant and M. tuberculosis was uncommon. Antibiotic side effects were relevant as well as the neurological complications.

Behavior and enterotoxin production by coagulase negative Staphylococcus in cooked ham, reconstituted skimmed milk, and confectionery cream.

In this study, the behavior and enterotoxin production by 10 different coagulase negative Staphylococcus (CNS) strains inoculated in cooked ham, reconstituted skimmed milk, and confectionery cream in the presence or absence of background microbiota have been investigated. After inoculation (103 CFU/g), foods were incubated at 25, 30, and 37 °C and aerobic mesophilic and CNS counts were carried out at 12, 24, 48, and 72 h. Staphylococcal enterotoxins (SE) detection was performed by SET-RPLA (Oxoid, Basingstoke, U.K.) and mini-Vidas® (bioMérieux, La Balme les Grottes, France). CNS counts increased during incubation and approached 106 to 107 CFU/g after 12 h at 37 °C in the 3 foods studied. At 25 °C, counts reached 106 to 107 CFU/g only after 24 to 48 h. The interference of background microbiota on CNS behavior was only observed when they grew in sliced cooked ham, which presented a high initial total count (105 CFU/g). Significantly higher counts of CNS isolated from raw cow's milk in comparison with food handlers isolates were found in reconstituted milk and confectionery cream. Although CNS strains were able to produce SEA, SEB, and SED in culture media, in foods, in the presence or absence of background microbiota S. chromogenes LE0598 was the only strain able to produce SEs. Despite the scarcity of reports on CNS involvement with foodborne disease outbreaks, the results found here support the CNS growth and SE production in foods even in the presence of background microbiota and may affect food safety.

Fourier transform infrared spectroscopy for rapid identification of nonfermenting gram-negative bacteria isolated from sputum samples from cystic fibrosis patients.

The accurate and rapid identification of bacteria isolated from the respiratory tract of patients with cystic fibrosis (CF) is critical in epidemiological studies, during intrahospital outbreaks, for patient treatment, and for determination of therapeutic options. While the most common organisms isolated from sputum samples are Pseudomonas aeruginosa, Staphylococcus aureus, and Haemophilus influenzae, in recent decades an increasing fraction of CF patients has been colonized by other nonfermenting (NF) gram-negative rods, such as Burkholderia cepacia complex (BCC) bacteria, Stenotrophomonas maltophilia, Ralstonia pickettii, Acinetobacter spp., and Achromobacter spp. In the present study, we developed a novel strategy for the rapid identification of NF rods based on Fourier transform infrared spectroscopy (FTIR) in combination with artificial neural networks (ANNs). A total of 15 reference strains and 169 clinical isolates of NF gram-negative bacteria recovered from sputum samples from 150 CF patients were used in this study. The clinical isolates were identified according to the guidelines for clinical microbiology practices for respiratory tract specimens from CF patients; and particularly, BCC bacteria were further identified by recA-based PCR followed by restriction fragment length polymorphism analysis with HaeIII, and their identities were confirmed by recA species-specific PCR. In addition, some strains belonging to genera different from BCC were identified by 16S rRNA gene sequencing. A standardized experimental protocol was established, and an FTIR spectral database containing more than 2,000 infrared spectra was created. The ANN identification system consisted of two hierarchical levels. The top-level network allowed the identification of P. aeruginosa, S. maltophilia, Achromobacter xylosoxidans, Acinetobacter spp., R. pickettii, and BCC bacteria with an identification success rate of 98.1%. The second-level network was developed to differentiate the four most clinically relevant species of BCC, B. cepacia, B. multivorans, B. cenocepacia, and B. stabilis (genomovars I to IV, respectively), with a correct identification rate of 93.8%. Our results demonstrate the high degree of reliability and strong potential of ANN-based FTIR spectrum analysis for the rapid identification of NF rods suitable for use in routine clinical microbiology laboratories.

Identificación de bacterias periodontopatógenas vs. diagnóstico etiológico y clínico / Identification of periodontopathogenic bacteria vs etiological and clinical diagnosis

Habiendo detectado en forma reiterada en trabajos científicos y proyectos de tesis doctoral, una tendencia en el medio científico de establecer una relación causal directo entre la identificación de bacterias periodontopatógenas por algunos de los variados métodos vigentes no cuantitativos, con el diagnóstico clínico etiológico, es propósito de este trabajo de revisión y actualización bibliográfica concientizar a docentes investigadores de que, si bien es cierto que en la actualidad se dispone de una amplia gama de técnicas y métodos de gran sensibilidad y especificidad para la detección e identificación de bacterias periodontopatógenas, la complejidad de la microbiota asociada a enfermedades periodontales hace prácticamente imposible relacionar los resultados de los hallazgos obtenidos con el diagnóstico etiológico y situaciones clínicas, tales como actividad de la enfermedad (evolución), respuesta al tratamiento, o detección de individuos predispuestos. Por lo tanto, meritúa marcar una clara delimitación de bacterias periodontopatógenas en la bolsa (o su correlación con determinaciones de constituyentes del fluido gingival y marcadores de sangre periférica) y el diagnóstico etiológico y clínico de paradenciopatías (AU)

Identificación de bacterias periodontopatógenas vs. diagnóstico etiológico y clínico / Identification of periodontopathogenic bacteria vs etiological and clinical diagnosis

Habiendo detectado en forma reiterada en trabajos científicos y proyectos de tesis doctoral, una tendencia en el medio científico de establecer una relación causal directo entre la identificación de bacterias periodontopatógenas por algunos de los variados métodos vigentes no cuantitativos, con el diagnóstico clínico etiológico, es propósito de este trabajo de revisión y actualización bibliográfica concientizar a docentes investigadores de que, si bien es cierto que en la actualidad se dispone de una amplia gama de técnicas y métodos de gran sensibilidad y especificidad para la detección e identificación de bacterias periodontopatógenas, la complejidad de la microbiota asociada a enfermedades periodontales hace prácticamente imposible relacionar los resultados de los hallazgos obtenidos con el diagnóstico etiológico y situaciones clínicas, tales como actividad de la enfermedad (evolución), respuesta al tratamiento, o detección de individuos predispuestos. Por lo tanto, meritúa marcar una clara delimitación de bacterias periodontopatógenas en la bolsa (o su correlación con determinaciones de constituyentes del fluido gingival y marcadores de sangre periférica) y el diagnóstico etiológico y clínico de paradenciopatías (AU)

Identificación de bacterias periodontopatógenas vs. diagnóstico etiológico y clínico / Identification of periodontopathogenic bacteria vs etiological and clinical diagnosis

Habiendo detectado en forma reiterada en trabajos científicos y proyectos de tesis doctoral, una tendencia en el medio científico de establecer una relación causal directo entre la identificación de bacterias periodontopatógenas por algunos de los variados métodos vigentes no cuantitativos, con el diagnóstico clínico etiológico, es propósito de este trabajo de revisión y actualización bibliográfica concientizar a docentes investigadores de que, si bien es cierto que en la actualidad se dispone de una amplia gama de técnicas y métodos de gran sensibilidad y especificidad para la detección e identificación de bacterias periodontopatógenas, la complejidad de la microbiota asociada a enfermedades periodontales hace prácticamente imposible relacionar los resultados de los hallazgos obtenidos con el diagnóstico etiológico y situaciones clínicas, tales como actividad de la enfermedad (evolución), respuesta al tratamiento, o detección de individuos predispuestos. Por lo tanto, meritúa marcar una clara delimitación de bacterias periodontopatógenas en la bolsa (o su correlación con determinaciones de constituyentes del fluido gingival y marcadores de sangre periférica) y el diagnóstico etiológico y clínico de paradenciopatías (AU)

First results from a screening of filamentous organisms present in Buenos Aires's activated sludge plants.

Activated sludge samples from municipal and industry plants were evaluated with the aim to recognise the mainly filamentous bacteria found. The routine tests recommended were performed: Gram, Neisser, PHB-Nilo blue epifluorescence reaction and S. The morphologic characteristics were determined. Correlation between environmental conditions and abundance of dominant bacteria were made. All plants were completely mixed configurations with anoxic reactor for denitrification ahead of main aerobic reactor. Also all systems were working at low F/M values or high sludge age (> ten days) and in some cases with low oxygen concentration. The dominant species were Type 021 N, Thiothrix I, Sphaerotilus natans, Microthrix parvicella, Nocardia sp, Type 1701, Type 1863, Type 0041 and Type 0092.

Nitrogenase activity of Beijerinckia derxii is preserved under adverse conditions for its growth

In order to evaluate the response of Beijerinckia derxii ICB-10 to different environmental factors, growth curves and specific nitrogenase activity were studied. Tested conditions were as follows: a) media with different pH values (2.5, 2.8, 4.2 and 5.7); b) medium supplemented with 230 æM aluminium sulphate; c) media with two different potassium phosphate concentrations (50 mM and 100 mM); d) shaken or still cultures; e) medium supplemented with 40 mM sodium thiosulphate. Growth curves and specific nitrogenase activity at pH 4.2 were closely similar to those for cultures at pH 5.7 (standard condition), whereas no growth occurred at pH 2.5. Changes in growth curves and/or specific nitrogenase activity were observed under the following conditions: I) pH 2.8 (decrease in initial CFU number, reduction of maximum specific growth rate, reduced number of generations and stimulation of nitrogenase activity), II) presence of aluminium (early death phase), III) 50 mM PO4(3-) (reduction of maximum specific growth rate), IV) 100 mM PO4(3-) (reduction of both number of generations and maximum specific growth rate as well as early death phase), V) low O2 availability (increasing nitrogenase activity), and VI) presence of thiosulphate (reduction of maximum specific growth rate; early death phase and high stimulation of nitrogenase activity). The data obtained showed the high variability of the cell growth response to environmental factors. Nitrogenase activity was always preserved even when population growth was affected

Primeras identificaciones de Rahnella aquatilis en Costa Rica / Firts identification of Rahnella aquatilis in Costa Rica

Se reporta el aislamiento de Rahnella aquatilis en dos pacientes, en muestras de secreción umbilical con fístula entero cutánea y orina de infección urinaria obtenida por punción vesical. Se mencionan las características bioquímicas que permiten su clasificación, así como su comportamiento ante los antimicrobianos. Se reporta que ambos casos se resolvieron exitosamente. Se hace revisión de la literatura al respecto y se señala la baja frecuencia de aislamiento de esta bacteria, en el campo clínico, a nivel mundial

Emended description of Herbaspirillum; inclusion of [Pseudomonas] rubrisubalbicans, a milk plant pathogen, as Herbaspirillum rubrisubalbicans comb. nov.; and classification of a group of clinical isolates (EF group 1) as Herbaspirillum species 3.

[Pseudomonas] rubrisubalbicans, a mild plant pathogen. Herbaspirillum seropedicae, and EF group 1 strains (clustered by an immunological method) were investigated by a polyphasic approach with DNA-rRNA and DNA-DNA hybridizations and auxanography on 147 substrates. Our results show that they all belong to the genus Herbaspirillum. In addition to H. seropedicae, two other species are described: Herbaspirillum rubrisubalbicans and a new unnamed species, Herbaspirillum species 3, containing mainly strains of clinical origin. The three species can be differentiated on the basis of their auxanographic features and DNA-DNA similarities. The type strain of H. rubrisubalbicans is NCPPB 1027 (=LMG 2286); representative strains of the third Herbaspirillum species are strains CCUG 189 (=LMG 5523), CCUG 10263 (=LMG 5934), and CCUG 11060 (=LMG 5321). It has been confirmed that H. rubrisubalbicans is an endophytic diazotroph. It colonizes the roots, the stems, and predominantly the leaves of sugarcane (Saccharum spp.), while Herbaspirillum seropedicae colonizes in large numbers many different species of the Gramineae. Both diazotrophic Herbaspirillum species could be differentiated with meso-erythritol and N-acetylglucosamine. Oligonucleotide probes based on partial sequences of the 23S rRNA of H. seropedicae and H. rubrisubalbicans (HS and HR probes, respectively), were constructed and used as diagnostic probes.

Imipenem - cilastatina versus ceftazidima - amikacina para el tratamiento de pacientes neutropénicos febriles / Imipenem - cilastatine versus ceftazidime - amikacin in the treatment of febril neutropenic patients

Aim: To compare the efficacy of imipenem - cilastatine and ceftazidime - amikacin in the treatment of febril neutropenic patients. Design: Open prospective and randomized clinical study. Patients: 52 patients (26 females) aged 16 to 80 years old with 60 episodes of neutropenia were studied. They were randomly assigned to receive Imipenem - cilastatine in doses of 500 mg iv qid or the combination of ceftazidime 1 to 1.5 g iv tid and amikacin 7.5 mg/kg iv bid. Results: Global response to initial therapy was 53 percent in patients receiving imipenem - cilastatine and 37 percent in those receiving ceftazidime - amikacin (p=ns). When other antimicrobial were added, a 90 and 85 percent infection eradication success was achieved respectively. Six febrile episodes in the group receiving imipenem - cilastatine and 12 episodes in tha group receiving ceftazidime - amikacin had Gram positive cocci as the sole treatment outcome. Three patients receiving imipenem - cilastatine (10 percent) and 4 receiving ceftazidime - amikacin (13 percent) died. Superinfections and toxicity related to antibiotics were minimal in both groups. Conclusions: imipenem - cilastatine and the combination of ceftazidime with amikacin were equally effective in the treatment of febril episodes in neutropenic patients

Quantitative skin cultures at potential catheter sites in neonates.

OBJECTIVE: To identify and quantify the bacterial and fungal flora present at body sites used for vascular catheterization of infants in a neonatal intensive care unit. DESIGN: Quantitative skin cultures were obtained from a group of neonatal patients to determine the bacterial flora found on the skin at four sites. Quantitative cultures of the jugular, subclavian, umbilical, and femoral sites were obtained on 50 infants, ranging in age from 2 days to 3 months old. SETTING: The neonatal intensive care unit of St. Christopher's Hospital for Children, a university-affiliated tertiary care children's hospital. RESULTS: Colony counts ranged from 0 to 10(6) colony-forming units/10 cm2. Types of organisms found were consistent with other published studies and included coagulase-negative staphylococci, Staphylococcus aureus, yeast, aerobic gram-negative rods, Enterococcus species, Corynebacterium species, and alpha-hemolytic streptococci. There was a significantly higher mean colony count at the combined jugular/femoral sites versus the subclavian site (P < 0.01) and umbilical site (P < 0.05). Mean colony counts did not differ significantly between the jugular and femoral site, or between the subclavian and umbilical site. The umbilical site was more likely to be colonized with aerobic gram-negative rods, Enterococcus species, and yeast, while the subclavian had coagulase-negative staphylococci as the predominant organism. The jugular and femoral sites demonstrated a higher colony count of aerobic gram-negative rods, Enterococcus species and yeast than the other sites. If central venous catheters need to be in place for extended periods of time, placement at a site with lower bacterial densities on the skin may help minimize catheter-associated infections. This study supports the subclavian as the preferred site.

Antibiotic-resistant gram-negative bacilli in the sewage of the City of Concepcion, Chile.

Counts of total and of antibiotic-resistant heterotrophic Gram-negative bacteria were performed in samples collected from the main sewage effluent of the city of Concepcion, Chile, during an eleven month period in 1991-1992. Antibiotic resistance patterns (ARP) were determined and antibiotic resistance indexes (ARI) were calculated for some fermenting and nonfermenting strains of resistant bacteria. Ampicillin-resistant strains were the most frequent among fermenting bacteria, whereas those cephalothin-resistant were the most frequent among nonfermenting bacilli. These results correlate with the frequency of clinical use of both antibiotics in the community of Concepción. Higher values of ARI for nonfermenting bacilli are probably due to the natural intrinsic resistance of these microorganisms to several beta-lactam compounds. Since plasmid-coded resistance is frequent among enteric bacilli, the large number of resistant bacilli in sewage may be important in the natural dis-

[Heterotrophic aerobic Gram negative bacilli from the Itata fluvial system, Chile]. / Bacilos Gram negativos heterotróficos aerobios del sistema fluvial Itata, Chile.

Total bacterial counts, counts of Gram negative bacilli and faecal pollution were determined in samples of freshwater collected in different sampling sites of the fluvial system Itata, in the Eight Region of Chile. These stations cover the course of the system from the Andes down to the Pacific Ocean. Bacterial counts were rather low and varied according to the human population density in the sampling sites. Most of the identified bacilli were nonfermenting bacilli, among which the highest number were identified as Pseudomonas spp. Among fermenting bacilli, the highest proportion of strains corresponded to Enterobacter. In those areas with human activities faecal contamination indexes were higher and strains of aeromonas were isolated.

Determinación de bacterias patógenas en el área quirúrgica de gineco-obstetricia del Centro Materno-Infantil San Lorenzo de los Mina, mayo-junio 1989 / Determination of pathogen bacterias in surgical area of gyneco-obstetrics of the Centro Materno-Infantil San Lorenzo de los Mina, May-June 1989

Se realizó un estudio observacional, analítico y transversal, durante los meses de mayo y junio 1989, para la determinación de la presencia de bacterias patógenas en el área quirúrgica de gineco-obstetricia en el Centro Materno Infantil San Lorenzo, de Los Mina, Distrito Nacional, R. D. Se cultivaron muestras que fueron tomadas del personal médico, paramedico y del área quirúrgica (equipos hospitalarios, instrumental quirúrgico y ambiente del quirófano), de donde se tomaron 25 cultivos, 10 en el personal mencionado y 15 en el área quirúrgica. En total hubo crecimiento en 8 cultivos para un 32 por ciento , todos ellos bacilos gram negativos