Ooquistes de Cryptosporidium sp. (Apicomplexa: Cryptosporidiiadae) y presencia del C. parvum en niños de Costa Rica

Artículo científico -- Universidad de Costa Rica. Instituto de Investigaciones en Salud, 1996-1997From 1982 to 1987 infant and preschool Costa Rican children with acute diarrhea were studied. Cryptospo­ ridium (Tyzzer 1912) and other agents of diarrhea were invetigated. Criptosporydium oocysts were diagnosed in Giemsa and acid-fast (Kinyoun) stained smears. Ten Cryptosporidium oocysts per positive smear were systemalically measured. Giemsa stained oocysts showed less variation respect to the mean. The oocysts corresponded to C. parvum with diameters of 5.0 x 4.5 µm but not to C. muris with oocysts of 7.4 10 5.6 µm.Universidad de Costa Rica. Instituto de Investigaciones en Salud.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Cellular interactions in the invasion process of Shigella sp

artículo (arbitrado)--Universidad de Costa Rica. Instituto de Investigaciones en Salud, 2009Shigella, como agente etiológico de la disentería bacilar, es un problema importante de salud pública a nivel mundial. Para el establecimiento de la infección este microorganismo emplea las funciones celulares y de defensa propias del hospedero como son las células M, los macrófagos y la “endocitosis” en su célula blanco, el enterocito para lograr la replicación y diseminación intra e intercelular. Las proteínas denominada Ipa (por “invasión plasmid antigen”) son importantes efectoras bacterianas involucradas directamente con el proceso de invasión celular. Estas proteínas se secretan al exterior por medio de un sistema denominado Sistema de Secreción tipo III o SSTT. Tanto los genes del SSTT como de las proteínas ipa (ipaB, ipaC, ipaD, ipaA, e IpgD) están codificados en los operones mxi /spa e ipa, en el plásmido de invasión de Shigella. Existen otros determinantes de virulencia codificados tanto en el pINV (icsA, ipaH) como en el cromosoma bacteriano (lipopolisacárido o LPS, enterotoxina 1, toxina Shiga, etc), que cumplen distintos roles durante la invasión. La transmigración de polimorfonucleares neutrófilos y la liberación de citoquinas proinflamatorias, disgregan la integridad de la barrera intestinal, facilitan la invasión y determinan el desarrollo clínico durante la shigelosis.Shigella, as an etiological agent of bacillary dysentery, is considered an important public health problem around the world. To establish infection, Shigella uses host cellular and defense mechanisms such as M cells, macrophages and “endocitosis” in the target cell: the enterocyte, followed by intracellular replication and spreading into adjacent cells. The invasion plasmid antigen (ipa) proteins are important bacterial effectors directly involved in the cellular invasion process. Ipa proteins are excreted by the Secretion System Type III (SSTT). SSTT and ipa genes (ipaB, ipaC, ipaD, ipaA, e IpgD) are encoded in the mxi/spa and ipa operons, carried on the Shigella invasion plasmid (pINV). Virulence factors as icsA and ipaH are encoded on pINV. Others such as lipopolisacharide (LPS), enterotoxin and Shiga toxin are encoded in the bacterial chromosome and play different roles in the invasion process. Transmigration of polymorphonuclear leucocytes and the release of proinflamammatoy cytokines disrupt the intestinal barrier which facilitates the invasion process and define the clinical symptoms of shigellosis.Universidad de Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Anemia hipocrómica en niños preescolares de una comunidad urbano marginal, San José, Costa Rica

Artículo científico -- Universidad de Costa Rica, Instituto de Investigaciones en Salud. 2002La Organización Mundial de la Salud (OMS) define anemia en niños menores de cinco años de edad como aquellos valores inferiores de hemoglobina (Hb) a 11 g/dL y de hematócrito (Hto) a 0.33 L/L (33%). Sin embargo, diversos estudios sobre anemia indican que una Hb menor a 10.5 g/dL retarda el desarrollo psicomotor y disminuye el desempeño cognoscitivo en lactantes y de niños en edad preescolar. Existen diferentes tipos de anemias nutricionales, entre estas la anemia par deficiencia de hierro constituye un problema pediátrico debido a su extraordinaria frecuencia durante la infancia, siendo la causa más común de anemia. La alta frecuencia y gravedad de esta anemia esta relacionada con una condición socioeconómica según la OMS la población mundial presenta anemia en 30% y la mitad de los casos se debe a deficiencia de hierro.Universidad de Costa Rica. Instituto de Investigaciones en SaludUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

The importance of integrons for development and propagation of resistance in Shigella: the case of Latin America

In Latin America, the disease burden of shigellosis is found to coexist with the rapid and rampant spread of resistance to commonly used antibiotics. The molecular basis of antibiotic resistance lies within genetic elements such as plasmids, transposons, integrons, genomic islands, etc., which are found in the bacterial genome. Integrons are known to acquire, exchange, and express genes within gene cassettes and it is hypothesized that they play a significant role in the transmission of multidrug resistance genes in several Gram-negative bacteria including Shigella. A few studies have described antibiotic resistance genes and integrons among multidrug resistant Shigella isolates found in Latin America. For example, in Brazil, Bolivia, Chile, Costa Rica and Peru, class 1 and class 2 integrons have been detected among multidrug resistant strains of Shigella; this phenomenon is more frequently observed in S. flexneri isolates that are resistant to trimethoprim, sulfamethoxazole, streptomycin, ampicillin, chloramphenicol, and tetracycline. The gene cassette sul2, which is frequently detected in Shigella strains resistant to the sulfonamides, suggests that the sulfonamide-resistant phenotype can be explained by the presence of the sul2 genes independent of the integron class detected. It is to be noted that sul3 was negative in all isolates analyzed in these studies. The high frequency of sulfonamide (as encoded by sul2) and trimethoprim resistance is likely to be a result of the recurrent use of trimethoprim sulfamethoxazole as a popular regimen for the treatment of shigellosis. The observed resistance profiles of Shigella strains confirm that ampicillin and trimethoprim-sulfamethoxazole are ineffective as therapeutic options. In-depth information regarding antibiotic resistance mechanism in this pathogen is needed in order to develop suitable intervention strategies. There is a pressing need for regional and local antimicrobial resistance profiling of Shigella to be included as a part of the public health strategy.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Cryptosporidium diarrhea in costarican children

Artículo científico -- Universidad de Costa Rica. Instituto de Investigaciones en Salud, 1986Coccidian parasites of the genus Cryptosporidium cause acute diarrhea in many vertebrates, including man. Recent reviews on the subject [1-5] were stimulated by demonstration of a chronic, debilitating and generally fatal diarrhea in immunodeficient and immunosuppressed individuals, and in persons with acquired immunodeficiency syndrome (AIDS) [6-16]. Additional interest arose after finding that cryptosporidiosis is not rare among immunocompetent or otherwise healthy children and adults, who suffer from acute diarrheal disease in industrialized and less developed countries [17, 18]. The first Cryptosporidium species (C. muris) was described by Tyzzer in 1907 [19], who found the parasite in gastric glands of the domestic mouse. Tyzzer described oocysts measuring 5-6 x7 pm, with 4 sporozoites of about 12-14 p.m after excystation [19, 20]. He attempted transmission of the coccidium to the white rat, without success. Later, Tyzzer described another species, C. parvum, with considerably smaller oocysts measuring 3.0-3.3 X 4.0-4.5 p.m; excisted sporozoites measured 5.5-6.0 p.m [21]. This species was found in the small intestine of the laboratory mouse, rabbit and chicken [33], Cryptosporidium is currently placed in Apicomplexa, Sporozoea, Coccidia, Eucoccidiida, Eimeriina, and Cryptosporidiidae [22]. Many years after description of these species, additional "species" were named according to the vertebrate hosts in which they were found [22]. Most authors regard these species unjustified for several reasons. Oocysts found in different vertebrates are of similar size and morphology as those of C. parvum [23]. Infection and cross-infection occurs with oocysts of C. parvum-like strains in several vertebrate species and in man. Antibodies to one particular strain of Cryptosporidrum have been detected in sera from diverse vertebrate hosts [24]. On the basis of this information, one single species was proposed [24], in analogy with Toxoplasma, although one expert proposed one species for each of the four groups of vertebrates harboring parasites [25].Universidad de Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Brote de diarrea asociado a Shigella sonnei debido a contaminación hídrica, San José, Costa Rica, 2001

artículo arbitrado -- Universidad de Costa Rica, Instituto de investigaciones en Salud. 2004.En julio del 2001, un brote de diarrea asociado a transmisión hidrica afecto a mas de 7000 personas residentes en el área urbana de San Jose. Desde su inicio se especulo sobre el papel de Shige- Ila spp., como uno de los posibles agentes etiologicos del mismo, por lo que el objetivo de este estudio fue determinar la presencia de esta bacteria en los cases de diarrea atendidos en una de las clinicas ubicadas en el area del brote y demostrar que Shigella spp. es un agente importante de diarrea en nuestro pais asociado con la transmision hidrica, particularmente por la baja dosis infectante y alta virulencia. Para este fin, se analizaron especimenes fecales de 49 pacientes con diarrea que acudieron a la clinica de Alajuelita, del 17 al 31 de julio del 2001. Se obtuvo 16 aislamientos de Shigella spp. (34,7%), 15 correspondieron a Shigella sonnei en tanto que solamente uno a Shigella flexneri. Los grupos etareos mas afectados fueron niños menores de 10 anos y personas mayores de 60 afios. El patron de sensibilidad a los antibioticos de las cepas aisladas mostro resistencia a 8 de los 11 antibioticos probados: trimetoprim/ sulfametoxazole, tetraciclina, ampicilina, eritromicina, cloranfenicol, cefalotina, amikacina y amoxicilina; y sensibilidad a norfloxacina, ciprofloxacina y gentamicina.No fue posible aislar Shigella spp. de las muestras de agua. Los resultados sugieren que este medio de transmisión estuvo relacionado con el brote de diarrea. El presente estudio demuestra Ia importancia de Shigella spp. como causa de diarrea sobre todo en niños pequeños, adultos mayores y su frecuente asociacion con brotes relacionados con agua contaminada. Los resultados también sugieren que el tratamiento contra Ia shigelosis debería incluir informacion acerca de los perfiles de resistencia a los antibioticos y de Ia necesidad de mas investigacion sobre vias de transmisión por agua y alimentos en la prevención de este tipo de brotes.During July of 2001, a diarrhea' outbreak affected more than 7000 individuals in the urban area of San Jose. Even though the origen of the outbreak was not found, faecal pollution of the drinking water from the metropolitan aqueduct it is suspected. The objetive of the study was to determinate the presence of Shigella spp., as a possible aetiological agent of the outbreak. Samples were collected during two weeks (july 17th to 31st) Sixteen Shige-Ila spp. isolates were obtained out of 49 patients with diarrhoea (34,7%), 15 of the isolates were Shigella sonnet and 1 corresponded to Shigella flexneri. The most affected age groups were children under 10 and people older than 60. The antibiotic susceptibility pattern of the Shigella spp. isolates showed that they were resistant to eigth of the antibiotics: trimethoprim/sulfamethoxazole, tetracycline, ampicillin, eritromicine, chloramphenicol, cephalotin, amikacine and amoxicillin. They were sensitive to norfloxacin, ciprofloxacin and gentamicin. Althought it was not possible to isolate Shigella ssp. directly from water, the results highly suggest this pathogen to be the aetiological agent of the outbreak. This study demonstrates the import role of Shigella spp. as cause of diarrhea affecting mainly small children and elderly people and its frequent association to outbreaks related to drinking water. This study also suggests that guidelines for treatment of shigellosis should include information on the antibiotic resistance pattern and further studies regarding the routes of transmission by water and food, will be required for strategies of prevention of such outbreaks.Universidad de costa Rica, Instituto de investigaciones en Salud.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Leishmaniasis tegumentaria americana en amerindios de Costa Rica

Artículo científico -- Universidad de Costa Rica, Instituto de Investigaciones en Salud. 1985Entre 1979 y 1984 se realizaron estudios clínicos y epidemiológicos en las poblaciones de Limoncito y Abrojo (Guaymi), Cabagra y Amubri (Bribri), Boruca (Boruca) y Ujarrás (Cabecar). Los estudios clínicos consistieron en una inspección y registro de la localización anatómica de lesiones y cicatrices y en intradermorreacciones con leishmanina. La frecuencia de lesiones y cicatrices y el desarrollo de sensibilidad cutanea al antigen de Montenegro, revelaron diversos patrons epidemiológicos de LTA en esas poblaciones. Limoncito, Boruca y Amubri rnostraron una intensa transmisión de Ia enfermedad explicable por su marcado ruralismo y estrecho contacto con la selva. La frecuencia de lesiones fue especialmente alta en niños, y Ia curva de hipersensibilidad cutánea mostró que casi toda Ia población ya desano116 inmunidad a los 18 años de edad. En Abrojo, Cabagra y Ujarrás la epidemiolog fa de la LTA fue diferente, en tanto la frecuencia de lesiones, cicatrices y reactividad cutánea fueron menos manifiestas que en Amubri y Limoncito, indicando mayor intervención del hombre sobre la selva. Con base en los hallazgos, se discute la epidemiologia de la LTA en los amerindios de Costa Rica, así como posibles soluciones pare su control.Clinical and epidemiologic studies were conducted between 1979 and 1984, in the communities of Limoncito and Abrojo (Guaymi), Cabagra and Amubri (Bribri), Boruca (Boruca) and Ujarrás (Cabecar). The clinical surveys seved to examine and record the distribution of lesions and scars of American cutaneous leishmaniasis (ACL), as well as the skin response to leishmanin. The frequency of lesions and scars and the development of cutaneous sensitivity to Montenegro antigen showed varying epidemiological patterns of ACL in such populations. Limoncito, Boruca and Amubri exhibited intense transmission of the disease accounted for by the marked ruralism and close contact of man with the forest. The frequency of lesions was specially high among children, and the curve of delayed skin sensitivity revealed that almost all the population had developed immunity at the age of 18 years. In Abrojo, Cabagra and Ujarrás, the epidemiology of ACL was different in that the frequency of lesions, scars and cutaneous reactions were less manifiest than in Amubri and Limoncito, indicating a greater interventions of man on the forest. Based on the findings, the epidemiology of ACL in Costa Rican Amerindians and its possible control, are discussed.Universidad de Costa Rica, Instituto de Investigaciones en SaludUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Detection of shigella in lettuce by the use of a rapid molecular assay with increased sensitivity

artículo (arbitrado)--Universidad de Costa Rica.Instituto de Investigaciones en Salud, 2010A Multiplex Polymerase Chain Reaction (PCR) assay to be used as an alternative to the conventional culture method in detecting Shigella and enteroinvasive Escherichia coli (EIEC) virulence genes ipaH and ial in lettuce was developed. Efficacy and rapidity of the molecular method were determined as compared to the conventional culture. Lettuce samples were inoculated with different Shigella flexneri concentrations (from 10 CFU/ml to 107 CFU/ml). DNA was extracted directly from lettuce after inoculation (direct-PCR) and after an enrichment step (enrichment PCR). Multiplex PCR detection limit was 104 CFU/ml, diagnostic sensitivity and specificity were 100% accurate. An internal amplification control (IAC) of 100 bp was used in order to avoid false negative results. This method produced results in 1 to 2 days while the conventional culture method required 5 to 6 days. Also, the culture method detection limit was 106 CFU/ml, diagnostic sensitivity was 53% and diagnostic specificity was 100%. In this study a Multiplex PCR method for detection of virulence genes in Shigella and EIEC was shown to be effective in terms of diagnostic sensitivity, detection limit and amount of time as compared to Shigella conventional culture.Universidad de Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Fecal contamination of the superficial water of the microbasin of Rio Purires, Costa Rica, 2010-2011

La contaminación fecal de las aguas superfciales es un problema importante para la salud pública, dada la transmisión de microorganismos patógenos. Se estima que las poblaciones ubicadas cerca de costas, ríos o lagos con elevada contaminación fecal, tienen mayor riesgo de desarrollar enfermedades infecciosas gastrointestinales. En esta investigación se analizó durante un año, la contaminación fecal en las aguas superfciales de la microcuenca del río Purires, ubicada en una zona de alta densidad poblacional en Costa Rica. En el 100% de las muestras se detectó contaminación fecal, siendo el punto de muestreo 3 el que mostró los niveles más altos, en promedio 2,2 x 104 Número Más Probable(NMP)/100 mL. Aunque los puntos 1 y 2 presentaron menor contaminación fecal, en promedio 6,4 x 102 NMP/100 mL y 6,3 x 103 NMP/100 mL respectivamente, estos valores indican también mala calidad de las aguas. Con estos resultados se pretende llamar la atención sobre la problemática ambiental de alta contaminación fecal en las aguas superfciales de esta microcuenca. Esta información es un insumo para desarrollar acciones de control sobre las fuentes de contaminación que afectan la calidad de las aguas y por ende, la salud de las poblaciones ubicadas en su cercanía.Fecal contamination of the superfcial waters is an important public health problem due to the presence of pathogenic microorganismsIt has been estimated that populations located close to coasts, rivers of lakes with an elevated fecal contamination have a higher risk of developing communicable gastrointestinal diseases. This investigation analyzed the fecal contamination of the superfcial waters of the microbasin of the Rio Purires, located in a highly populated area of Costa Rica. Fecal contamination was detected in 100% of the samples, and sample point 3 was the one that showed the highest levels, with an average of 2.2 x 104 Most Probable Number (MPN)/100mL. Even thought points 1 and 2 presented a lower fecal contamination, an average of 6.4 x 102 MPN/100mL and 6.3 x 103 MPN/100mL, respectively, these values also indicate low quality water. With these results we intend to alert regarding the problem of a high fecal contamination of superfcial waters of this microbasin. This information is an input for developing control actions over the contamination sources which compromise the quality of water and, therefore, the health of the populations located in its vicinityUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Implementation of two plate count methods for detection of somatic coliphages and contributions to the standard methodologies

Los métodos de recuento en placa capa doble y capa simple de agar, para la cuantifcación de colifagos somáticos en aguas, fueron implementados utilizando como base metodologías estándar. Diferentes variables fueron ensayadas, lo cual permitió la precisión en algunos pasos no incluidos en metodologías estándares. De los hallazgos de mayor importancia, se exponen las consecuencias de utilizar un cultivo de Escherichia coli excesivamente concentrado y se describe la obtención de un cultivo en fase logarítmica en solo 4 horas de incubación, ajustando la concentración a una densidad óptica de 0,3 a 600nm (3,1 x 108 UFC/ mL), o a un McFarland 1 (3,0 x108 UFC/ mL). Se determinó que los controles de colifagos deben ser almacenados a -70 °C para reducir su degradación y que se deben evitar cantidades superiores a 20 mL de mezcla de reacción por plato de Petri, para reducir las burbujas que pueden interferir con la lectura de unidades formadoras de placas (UFP). Se demostró que los colifagos de las muestras de agua pueden almacenarse 48 horas a 4 °C sin que sufran degradación y que en las muestras con altas concentraciones de colifagos no se observa UFP porque se da una lisis confluente de la capa bacteriana. No se encontraron diferencias signifcativas en la recuperación de colifagos al utilizar un método u otro, pero dichos métodos deben ser evaluados por medio de controles, antes de aplicarlos directamente en el análisis de muestras de agua.Two plate count methods, double layer and single layer of agar for quantifcation of somatic coliphages in water, were implemented using standard methodologies. Several variables were tested and provided valuable information that was not included in standard methodologies. The most important fndings are described, such as the effect of using an excessively concentrated culture of E. coli and production of a log phase culture in only 4 hours of incubation, adjusting the concentration to an optical density of 0.3 at 600 nm (3.1 x 108 CFU / mL), or to McFarland 1 (3.0 x 108 CFU / mL). It was determined that coliphages controls must be stored at -70 °C to reduce its degradation. Quantities of reaction mixture exceeding 20 mL per Petri dish must be avoided to prevent interfere with bubbles during the counting of plate forming units (PFU). It was demonstrated that coliphages isolated from water samples can be stored for 48 hours at 4 °C without any degradation, and PFU are not observed in samples with high concentrations of coliphages, because a confluent lysis of the bacterial layer. There was no signifcant difference in the recovery of coliphages using doble layer or single layer methods, but such methods should be evaluated by means of controls, before applying them directly in the analysis of water samplesUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA