Evelyn Rodríguez

Isolates of Clostridium perfringens recovered from Costa Rican patients with antibiotic-associated diarrhoea are mostly enterotoxin-negative and susceptible to first-choice antimicrobials.

To assess the prevalence of enterotoxigenic Clostridium perfringens among adults suffering from antibiotic-associated diarrhoea in a Costa Rican hospital, faecal samples were analysed from 104 patients by a cultivation approach. The 29 strains obtained, which accounted for an isolation frequency of 28 %, were genotyped and investigated with regard to their in vitro susceptibility to penicillin, imipenem, cefotaxime, chloramphenicol and metronidazole using an agar-dilution method. A multiplex PCR for detection of the toxins alpha, beta and epsilon predictably classified all faecal isolates as biotype A. An agglutination assay revealed that only one isolate synthesized detectable amounts of enterotoxin (detection rate 3 %). This result was confirmed by a PCR targeting the cpe gene. The spores of the only CPE(+) isolate did not germinate after incubation for 30 min at temperatures above 80 degrees C. Most isolates were susceptible to first-choice antimicrobials. However, unusual MICs for penicillin (16 microg ml(-1)) and metronidazole (512 microg ml(-1)) were detected in one and three isolates, respectively. The low incidence of enterotoxigenic strains suggests that C. perfringens was not a major primary cause of antibiotic-associated diarrhoea in this hospital during the sampling period.

Fungal contamination of stored automobile-fuels in a tropical environment.

Because of the lack of reports, the base levels of microbial contamination on stored fuels are unknown in tropical regions and it is unclear whether these levels have some influence on fuel quality parameters. Therefore, fungal quality in automobile fuels stored across Costa Rican territory was evaluated during two years according to the standard ASTM D6974-04. For a total of 96 samples, counts and identification of molds and yeasts were performed on regular gas, premium gas and diesel taken from the bottom and superior part of the container tanks. The highest contamination was found on the bottom of the tanks, where an aqueous phase was usually identified, showing populations over the ones present in the hydrocarbon itself (up to 10(8) CFU/L). Diesel was the most contaminated fuel (up to 10(7) CFU/L); however, an alteration on the physicochemical parameters was not observed in any kind of fuel. Seventy-five mold strains were isolated, Penicillium sp. being the most common genus (45.8% of the samples), and ten yeast strains, from the genera Candida sp. and Rhodotorula sp. Four of the yeasts were able to grow on diesel as the sole carbon source, at concentrations ranging from 0.5% to 25%. Increasing the frequency of tank cleaning, adding antimicrobial agents and monitoring microbial populations are recommended strategies to improve microbial quality of stored fuels.

Clostridium botulinum en suelos de Costa Rica

Inflorescences of Baclris gasipaes (a moooecioos neolropica1 pahn) present a strong prezigotic resource allocation toward masculinity on the inflorescence. Male reproductive effort (ERM. biomass) was 0.82 ± 0.11 g male flowers / g inflorescence. A high conelatioo between me total inflorescence biomass with female reproductive effort (ERF) (r= 0.76), indicates that plants wim bigger inflorescences allocate more resources to ihe female functioos. The pistillate flowers are situated preferentially in me inner pans of rachillas. Early ideas about evolution of protoginy, resource allocation and plant sexual systems are supported by these data.

Bacterias de importancia clínica en respiradores y aires acondicionados de hospitales de San José, Costa Rica

Introduccion. El riesgo de adquirir infecciones nosocomiales respiratorias, cuya tasa de mortalidad puede ser hasta del 76%, aumenta con el uso de respiradores y aires acondicionados, de manera que detectando bacterias de importancia medica en ellos se pretende contribuir a controlar dichas infecciones en hospitales costarricenses. Material y metodos. En cuatro hospitales, se analizaron 120 muestras de agua acumulada en 79 respiradores y 41 aires acondicionados; cada una se concentro por filtracion, se resuspendio y se inoculo en medios de cultivo adecuados. Los aislamientos se identificaron utilizando un sistema semiautomatizado API® y el metodo de Kirby y Bauer o tiras ATB® para las pruebas de sensibilidad. Resultados. El 80% de los aires acondicionados y 53% de los respiradores fueron positivos, lo que representa un 63% de muestras positivas. La mayoria de los aislamientos fueron bacilos Gram negativos (73%), Pseudomonas y generos relacionados el grupo mas frecuente (47%), mostrando mayor resistencia antimicrobiana hacia cefalotina (77%), menor a imipenem (6%) y una multirresistencia de 64%. Staphylococcus fue el genero mas frecuente de los cocos Gram positivos (84%), con la mayor resistencia a rifampicina (86%), la menor a penicilina (25%) y una multirresistencia del 50%; seis cepas (todas coagulasa negativas) fueron resistentes a vancomicina. Discusion. El alto porcentaje de muestras positivas con bacterias de importancia medica representa un riesgo para los pacientes, especialmente en salas de cuidados intensivos y de cirugia. El predominio de Gram negativos concuerda con su importancia en neumonias nosocomiales; su presencia indica contaminacion con el ambiente hospitalario o mala higiene al manipular el equipo. La alta multirresistencia encontrada es preocupante y debe llamar la atencion de las autoridades en salud.

The swarming phenomenon of Clostridium tetani

Inflorescences of Baclris gasipaes (a moooecioos neolropica1 pahn) present a strong prezigotic resource allocation toward masculinity on the inflorescence. Male reproductive effort (ERM. biomass) was 0.82 ± 0.11 g male flowers / g inflorescence. A high conelatioo between me total inflorescence biomass with female reproductive effort (ERF) (r= 0.76), indicates that plants wim bigger inflorescences allocate more resources to ihe female functioos. The pistillate flowers are situated preferentially in me inner pans of rachillas. Early ideas about evolution of protoginy, resource allocation and plant sexual systems are supported by these data.

Clostridios mesófilos en suelos de la Meseta Central de Costa Rica

Inflorescences of Baclris gasipaes (a moooecioos neolropica1 pahn) present a strong prezigotic resource allocation toward masculinity on the inflorescence. Male reproductive effort (ERM. biomass) was 0.82 ± 0.11 g male flowers / g inflorescence. A high conelatioo between me total inflorescence biomass with female reproductive effort (ERF) (r= 0.76), indicates that plants wim bigger inflorescences allocate more resources to ihe female functioos. The pistillate flowers are situated preferentially in me inner pans of rachillas. Early ideas about evolution of protoginy, resource allocation and plant sexual systems are supported by these data.