María Laura Arias

Seroepidemiology of Toxoplasma gondii (Apicomplexa) in meat producing animals in Costa Rica

A serologic screening for Toxoplasma gondii antibodies by IgG indirect fluorescent antibodies test (IgG-IFAT) was carried among 496 swine and 601 cattle serum samples from throughout Costa Rica, to study the possible role of their meat in the transmission of the parasite. The overall prevalence of antibodies was 34.4% in cattle and 43.8% in swine. No significant differences were found in the antibody prevalence between males and females in both animal groups, which acquire the infection early in their lives. Swine did not present significant differences between age groups. In cattle there was a high percent of seropositivity between the first and third years of age. The provinces that showed a greater number of seropositive animals were Limón and Puntarenas for both animals, and Guanacaste for cattle.

Species distribution and susceptibility to azoles of vaginal yeasts isolated prostitutes.

Objective. We investigated the use of miconazole among female prostitutes in Costa Rica as well as the distribution of vaginal yeasts and the susceptibility pattern to azoles of strains obtained from this population. Our intention was to relate a frequent use of miconazole to occurrence of vaginal yeasts resistant to azoles. Methods. Vaginal samples were taken from 277 patients that have previously used azoles. Vaginal swabs were obtained for direct microscopy and culture. Yeast isolates were identified by germ tube test and assimilation pattern. Susceptibility testing was determined using a tablet diffusion method. Results. The number of clinical Candida isolates (one from each patient) was 57 (20.6%). C. albicans was the predominant species (70%), followed by C. parapsilosis (12%), C. tropicalis (5.3%), C. glabrata and C. famata (3.5% each), C. krusei, C. inconspicua and C. guilliermondii (1.7% each). The majority of vaginal Candida isolates were susceptible to ketoconazole (91%), fluconazole (96.5%), and itraconazole (98%). A lower susceptibility of some isolates to miconazole (63%) was observed as compared to the other azoles tested. Moreover, the strains, nonsusceptible to miconazole, were more often obtained from patients that have used this antifungal at least four times within the last year before taking the samples as compared to those with three or less treatments (P<.01). Conclusion. An indiscriminate use of miconazole, such as that observed among female prostitutes in Costa Rica, results in a reduced susceptibility of vaginal yeasts to miconazole but not to other azoles.

Determination of Toxoplasma gondii in several organs of cattle by carbon immunoassay (CIA) testing

Samples of muscle, heart, liver and lung were tested for the presence of Toxoplasma gondii using mice as a biologic detector and the carbon immunoassay (CIA) for immunological diagnosis. In positive tissues the percentage of samples positive ranged from 10 to 50% which indicates the importance of cattle in the epidemiology of Toxoplasma in Costa Rica. We discuss these findings in relation to the transmission of the parasite in Costa Rica.

Arcobacter butzleri: first isolation report from chicken carcasses in costa rica

Arcobacter butzleri isolation from chicken carcasses in Costa Rica is reported for the first time. The isolated strains (P and R) were presumptively identified by their phenotypic characteristics. Definitive identification was made using a multiplex PCR assay for the simultaneous detection and identification of Arcobacter butzleri, Arcobacter cryaerophilus and Arcobacter skirrowii. These first isolations indicate the necessity of further investigation about the prevalence, distribution, ecology and interactions with human beings of this and other Arcobacter species.

Costa Rican Pot-Honey: Its Medicinal Use and Antibacterial Effect

There are very few records on the use of pot-honey by indigenous people of Costa Rica. Our evaluation concerns antimicrobial activity of honey samples from Tetragonisca angustula, Melipona beecheii and Apis mellifera, performed to determine whether traditional appreciation of stingless bee honey from Costa Rica, over that of A. mellifera honey, is justified by this criterion. The stingless bee honeys were more active than that of A. mellifera against Staphylococcus aureus and Pseudomonas aeruginosa―currently the major causes of burn and wound infections. The results presented herein are among the first steps towards further study of antimicrobial components in Costa Rican stingless bee honey.

The antimicrobial activity and microbiological safety of stingless bee honeys from Costa Rica

Summary Stingless bee honeys from Costa Rica possess etnopharmacological value mainly as a wound dressing. The microbiological study by APHA methods reported that 83 % of the honeys analysed had microbial counts that comply with European Pharmacopoeias acceptance criteria for microbiological quality of non-sterile substances for pharmaceutical use. All samples reported the absence of Clostridium botuiinum spores by PCR. Over 90 % of Tetragonisca angustula and Melipona beecheii honeys inhibited Pseudomonas aeruginosa and Staphylococcus aureus at minimum inhibitory concentrations lower than MedihoneyTM. Under the conditions tested, MedihoneyTM was not active against Candida albicans, whereas 53 % of T angustula honeys rendered inhibition. The melissopalynological analyses reported a homogeneous (monofloral) botanical composition for the Meliponini honeys, which emphasizes the contribution of nectar constituents to the antimicrobial activity and provides foundation to the standardization of a desired inhibitory effect. The traditional use of Costa Rican stingless bee honey as a dressing for burns and wounds reveals the application of a proficient antiseptic agent with low health associated risks.

Scattering of light by colloidal aluminosilicate particles produces the unusual sky-blue color of Río Celeste (Tenorio volcano complex, Costa Rica).

Río Celeste (Sky-Blue River) in Tenorio National Park (Costa Rica), a river that derives from the confluence and mixing of two colorless streams—Río Buenavista (Buenavista River) and Quebrada Agria (Sour Creek)—is renowned in Costa Rica because it presents an atypical intense sky-blue color. Although various explanations have been proposed for this unusual hue of Río Celeste, no exhaustive tests have been undertaken; the reasons hence remain unclear. To understand this color phenomenon, we examined the physico-chemical properties of Río Celeste and of the two streams from which it is derived. Chemical analysis of those streams with ion-exchange chromatography (IC) and inductively coupled plasma atomic emission spectroscopy (ICP-OES) made us discard the hypothesis that the origin of the hue is due to colored chemical species. Our tests revealed that the origin of this coloration phenomenon is physical, due to suspended aluminosilicate particles (with diameters distributed around 566 nm according to a lognormal distribution) that produce Mie scattering. The color originates after mixing of two colorless streams because of the enlargement (by aggregation) of suspended aluminosilicate particles in the Río Buenavista stream due to a decrease of pH on mixing with the acidic Quebrada Agria. We postulate a chemical mechanism for this process, supported by experimental evidence of dynamic light scattering (DLS), zeta potential measurements, X-ray diffraction and scanning electron microscopy (SEM) with energy-dispersive spectra (EDS). Theoretical modeling of the Mie scattering yielded a strong coincidence between the observed color and the simulated one.

Contamination of bovine milk with residues of inhibitory substances in 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.

Antimicrobial Resistance in Campylobacter spp.

The resistance of infectious agents to a broad range of antimicrobial drugs is a growing public health problem, which raises significant social concerns. This chapter describes the main antimicrobial resistance problems in developed and developing countries and the possible relationship between the resistances of Campylobacter strains found in poultry and humans. Determining the level of the problem is essential for control, formulating, and monitoring an effective response to antimicrobial resistance.

Patrón de sensibilidad a antibióticos de bacterias Gram negativas aisladas a partir de fórmulas enterales

Introduccion. Las formulas enterales contaminadas representan un riesgo para el desarrollo de infecciones nosocomiales y de pacientes hospitalarios. El objetivo de este estudio fue identificar 75 cepas de bacilos Gram negativos, aislados a partir de formulas enterales, distribuidas en los tres mayores centros hospitalarios costarricenses y evaluar su patron de sensibilidad a los antibioticos. Material y metodos. Se utilizaron dos tecnicas diferentes para el desarrollo del proyecto: la tecnica modificada de Kirby Bauer y la tecnica ATB antibiograma (Biomeriaux®). Resultados. A partir de las muestras analizadas, los grupos predominantes fueron Aeromonas sp., (22,7%), Klebsiella sp. y Proteus sp. (18,7% cada una) y Enterobacter sp. (4%). De acuerdo a los patrones de sensibilidad a los antibioticos obtenidos usando la tecnica de Kirby-Bauer modificada, 36% de las cepas mostraron resistencia a amoxicilinaacido clavulanico, 25,3% a cefaclor y 14,7% a cefuroxime. Todas las cepas fueron sensibles a imipenem y ciprofloxacina. Utilizando la tecnica ATB antibiograma, las bacterias mostraron resistencia a la amoxicilina (74,6%), amoxicilinaacido clavulanico (34,6%), ticarcilina-cefalotina (22,6%) y piperacilina (2,6%). Todas las cepas fueron sensibles a los otros diez antibioticos evaluados. Conclusiones. Es urgente asegurar una higiene estricta durante la preparacion y manejo de las soluciones enterales utilizadas en los hospitales, de manera que no representen un foco potencial de contaminacion con bacterias resistentes que puedan limitar la recuperacion de los pacientes.