Two hundred and one strains of M. haemolytica isolated from nasal exudate of dairy cattle were used, 123 strains from clinically healthy (CH) bovines and 78 from clinically ill (CI) bovines affected by pneumonia, obtained from a dairy complex in the Tizayuca region of the state of Hidalgo, Mexico. Strains were previously identified by conventional culture and biochemical tests, and serotyped by indirect haemagglutination. Disk diffusion test was performed to determine antimicrobial resistance to antibiotics, such as: ampicillin, gentamicin, ceftiofiur, penicillin, streptomycin, trimethoprim-sulfamethoxazole, tetracycline and erythromycin. Frequencies of higher antimicrobial resistance were: streptomycin (81.6%) and gentamicin (24.4%), all strains were susceptible to ampicillin and penicillin. Because of the high resistant strain frequency (81.6%) of M. haemolytica to streptomycin, obtained by Kirby-Bauer test, presence of the strA gene, which encodes the enzyme aminoglycoside-3-phosphotransferase that provides resistance to streptomycin, PCR was performed by testing the presence of the strA gene. Of the 201 strains tested, 42.7% showed the gene sfrA, 17.4% of which was serotype A1, 1.4% serotype A6 and 23.8% non-typeable strains. Of the 78 CI strains and 123 CH strains, 80% and 18.7%, had the gene sfrA, respectively.

Se emplearon 201 cepas de Mannheimia haemolytica provenientes de muestras de exudado nasal de bovinos productores de leche, 123 de bovinos clínicamente sanos (CS) y 78 de bovinos enfermos de neumonía (CE), obtenidas de un complejo lechero en la región de Tizayuca, Hidalgo, México, las cuales fueron identificadas previamente mediante pruebas convencionales de cultivo y bioquímicas, y serotipificadas mediante la prueba de hemaglutinación indirecta. Se les realizó la prueba de difusión en placa para determinar la resistencia a diversos antimicrobianos como ampicilina, gentamicina, ceftiofiur, penicilina, estreptomicina, trimetoprim con sulfametoxazol, tetraciclina y eritromicina. Las frecuencias más altas en la resistencia a antimicrobianos se presentaron a la estreptomicina (81.6%) y gentamicina (24.4%), todas las cepas fueron susceptibles a la ampicilina y penicilina. Debido a la alta frecuencia (81.6%) de cepas de M. haemolyfica resistentes a St con la técnica de Kirby-Bauer, se buscó la presencia del gen sfrA. Se realizó la técnica de PCR para comprobar la presencia del gen sfrA que codifica para la enzima aminoglycoside-3-phosphofransferase que proporciona resistencia contra la estreptomicina. Del total de cepas estudiadas (n = 201), 42.7% presentaron el gen sfrA, del cual 17.4% pertenecía al serotipo A1, 1.4% al A6 y 23.8% a cepas no tipificables. De las 78 cepas de CE y las 123 de CS, 80.0% y 18.7% respectivamente, presentaron el gen sfrA.

Los humedales de San Pedro sostienen redes tróficas del sistema fluvial debido a la alta disponibilidad de hábitats y a sus variaciones espacio-temporales. En esta investigación se estudió la composición, densidad y biomasa de la ictiofauna de los humedales; se capturaron 1 049 organismos de 25 especies, dos son exóticas: Oreochromis niloticus y Parachromis managuense. Con 23 especies capturadas en el sitio I, 17 en el II y 14 en el III. En la época de secas se obtuvo mayor riqueza con 21 especies, lluvias con 17 y cinco en nortes. La mayor densidad se mostró en el sitio II (0.23ind./m²), seguido de los sitios I y III (0.12, 0.12ind./m²). La mayor biomasa fue en secas (8.30g/m²), seguida de lluvias (2.1g/m²) y por último nortes (0.01g/m²). La mayor densidad se mostró en secas (0.43ind./m²) y la mínima en nortes (0.023ind./m²). Las especies dominantes en densidad según el diagrama Olmstead-Tukey fueron: Petenia splendida, Vieja heterospila, Vieja synspila, Dorosoma petenense y Astyanax aeneus. Por lo tanto, existieron diferencias significativas en los parámetros ecológicos y ambientales. Al considerar la variación en la riqueza podemos concluir que los humedales del río San Pedro, es un sistema donde la composición de la ictiofauna responde a las fluctuaciones espaciales y temporales.

Ichthyofauna from wetlands of San Pedro, Balancán, Tabasco, México. San Pedro River’s wetlands sustain trophic nets in the fluvial system, due to the high habitat availability, and space and temporal variations. In order to describe the relationship between environmental parameters and ichthyofauna, this study evaluated fish assemblages composition, distribution, abundance, density, biomass, richness species, diversity and equitability in the wetlands. Sampling considered three different sites and climatic seasons (dry, rainy and cold fronts). The physical and chemical parameters considered were dissolved oxygen, temperature, pH, water transparency and the depth. Fishes were caught with a shrimp net, after six minutes towings and were identified afterwards. A total of 1 049 organisms of 25 fish species were caught, two of which were exotic species: Oreochromis niloticus and Parachromis managuense. A total of 23 species were found at site I (with the highest density 0.23ind./m²), 17 at site II (0.23ind./m²) and 14 at site III (0.12ind./m²). The dry season had the highest species number with 21 species, followed by the rainy season with 17 species, and the cold season with five species. Similarly, the highest biomass (8.30g/m²) was found in dry season, followed by the rainy (2.16g/m²) and the cold seasons (0.03g/m²). Considering seasons, highest density was found during the dry (0.436ind./m²), followed by the rainy (0.213ind./m²) and the cold (0.023ind./m²) seasons. The dominant density species during the study period, according to the quadrants graphic of Olmstead-Tukey were: Petenia splendida, Vieja heterospila, Vieja synspila, Dorosoma petenense and Astyanax aeneus. There were significant differences in the species richness among sites. Temperature, depth and transparency showed differences among the seasons. The canonical correspondence analysis indicated that fish distribution was governed by environmental parameters during all seasons. In terms of fish abundance and composition, environmental parameters play an important role showing spatial and temporal differences in the ecosystem, this could be explained with the fact that most of young fishes have a movement behavior to the wetlands, searching refuge and feed during the dry season. Considering the diversity indexes variation, it may be concluded that San Pedro River’s wetlands correspond to a system where the ichthyofauna composition fluctuates spatial and seasonally. Rev. Biol. Trop. 59 (2): 693-708. Epub 2011 June 01.

Background: Those working in a hospital environment are exposed to different occupational risks, although more specifically biological ones. One of the major risks is that of exposure by airborne transmission, more specifically, tuberculosis. This study is aimed at providing a description and analysis of the results of the implementation of an evaluation and surveillance protocol following occupational exposure to Multiresistant mycobacterium bovis (MRMb). Method: A male patient was diagnosed with MRMb infection at the Miguel Servet Hospital in Zaragoza in 1999 following ten days without respiratory isolation. During this period, he came into contact with 167 employees from different hospital departments. A surveillance and contact control protocol was prepared based on: completing a survey and undergoing an initial Mantoux (if the employee had previously tested negative for tuberculin), followed three months later by a chest X-ray and then a two-year clinical follow-up (check-ups every three months) for those having tested positive for tuberculin and no administering of chemoprophylaxis even though signs of infection were to have been found. Results: Information was gathered on 160 employees (96%). A total of 94 employees (59%) had previously undergone a Mantoux, seven (7) having had tuberculosis. It was necessary for a follow-up to be conducted on sixty-one (61) employees who tested positive (29 previously positive and 32 detected in the initial Mantoux). No employee who had tested negative on an initial Mantoux tested positive on repeated testing three months later nor showed any symptoms indicative of transmission during the follow-up period. Some variables, such as age or working in the Infectious Disease Unit were related, on a statistically significant basis, to follow-up being required. Conclusions: The risk of occupational transmission following contact with MRMb might be similar to M. Tuberculosis, although further experience would be required in order to confirm this fact. Early diagnosis and availing of a protocol for implementing measures aimed at preventing and controlling this type of occupational exposure are of importance.

Fundamento: Los trabajadores del medio hospitalario están expuestos a diversos riesgos laborales, aunque los más específicos son los biológicos. Dentro de ellos, los asociados a la transmisión respiratoria y en concreto a la tuberculosis, ocupan un lugar destacado. El objetivo de este trabajo es describir y analizar los resultados de la aplicación de un protocolo de evaluación y vigilancia tras una exposición laboral a Mycobacterium bovis multiresistente (MbMR). Método: Un paciente varón fue diagnosticado en 1999 de infección por MbMR tras 10 días sin aislamiento respiratorio, en el hospital Miguel Servet (Zaragoza). Durante ese tiempo estuvo en contacto con 167 trabajadores de distintos servicios hospitalarios. Se elaboró un protocolo de vigilancia y control de contactos basado en: cumplimentación de una encuesta y realización de un Mantoux inicial (si el trabajador era tuberculín negativo previo) y tres meses después, radiografía de tórax y seguimiento clínico de 2 años (controles cada 3 meses) en tuberculín positivos y la no administración de quimioprofilaxis aunque se evidenciara infección. Resultados: Se obtuvo información de 160 trabajadores (96%). 94 trabajadores (59%) tenían realizado un Mantoux previo y 7 habían padecido tuberculosis. Fue necesario el seguimiento de 61 tuberculín positivos (29 previamente positivos y 32 detectados en el Mantoux inicial). Ningún trabajador con Mantoux inicial negativo tuvo un resultado positivo al repetirlo a los 3 meses ni manifestó síntomas sugerentes de transmisión durante el período de seguimiento. Algunas variables, como la edad o trabajar en el servicio de Infecciosas, se asociaron de forma estadísticamente significativa con la necesidad de seguimiento. Conclusiones: El riesgo de transmisión ocupacional tras un contacto con MbMR podría ser similar a M. tuberculosis, aunque es necesaria mayor experiencia para confirmar este hecho. Es importante un diagnóstico precoz y la existencia de un protocolo para implementar medidas preventivas y de control en este tipo de contactos laborales.

Background: Those working in a hospital environment are exposed to different occupational risks, although more specifically biological ones. One of the major risks is that of exposure by airborne transmission, more specifically, tuberculosis. This study is aimed at providing a description and analysis of the results of the implementation of an evaluation and surveillance protocol following occupational exposure to Multiresistant mycobacterium bovis (MRMb). Method: A male patient was diagnosed with MRMb infection at the Miguel Servet Hospital in Zaragoza in 1999 following ten days without respiratory isolation. During this period, he came into contact with 167 employees from different hospital departments. A surveillance and contact control protocol was prepared based on: completing a survey and undergoing an initial Mantoux (if the employee had previously tested negative for tuberculin), followed three months later by a chest X-ray and then a two-year clinical follow-up (check-ups every three months) for those having tested positive for tuberculin and no administering of chemoprophylaxis even though signs of infection were to have been found. Results: Information was gathered on 160 employees (96%). A total of 94 employees (59%) had previously undergone a Mantoux, seven (7) having had tuberculosis. It was necessary for a follow-up to be conducted on sixty-one (61) employees who tested positive (29 previously positive and 32 detected in the initial Mantoux). No employee who had tested negative on an initial Mantoux tested positive on repeated testing three months later nor showed any symptoms indicative of transmission during the follow-up period. Some variables, such as age or working in the Infectious Disease Unit were related, on a statistically significant basis, to follow-up being required. Conclusions: The risk of occupational transmission following contact with MRMb might be similar to M. Tuberculosis, although further experience would be required in order to confirm this fact. Early diagnosis and availing of a protocol for implementing measures aimed at preventing and controlling this type of occupational exposure are of importance.

Fundamento: Los trabajadores del medio hospitalario están expuestos a diversos riesgos laborales, aunque los más específicos son los biológicos. Dentro de ellos, los asociados a la transmisión respiratoria y en concreto a la tuberculosis, ocupan un lugar destacado. El objetivo de este trabajo es describir y analizar los resultados de la aplicación de un protocolo de evaluación y vigilancia tras una exposición laboral a Mycobacterium bovis multiresistente (MbMR). Método: Un paciente varón fue diagnosticado en 1999 de infección por MbMR tras 10 días sin aislamiento respiratorio, en el hospital Miguel Servet (Zaragoza). Durante ese tiempo estuvo en contacto con 167 trabajadores de distintos servicios hospitalarios. Se elaboró un protocolo de vigilancia y control de contactos basado en: cumplimentación de una encuesta y realización de un Mantoux inicial (si el trabajador era tuberculín negativo previo) y tres meses después, radiografía de tórax y seguimiento clínico de 2 años (controles cada 3 meses) en tuberculín positivos y la no administración de quimioprofilaxis aunque se evidenciara infección. Resultados: Se obtuvo información de 160 trabajadores (96%). 94 trabajadores (59%) tenían realizado un Mantoux previo y 7 habían padecido tuberculosis. Fue necesario el seguimiento de 61 tuberculín positivos (29 previamente positivos y 32 detectados en el Mantoux inicial). Ningún trabajador con Mantoux inicial negativo tuvo un resultado positivo al repetirlo a los 3 meses ni manifestó síntomas sugerentes de transmisión durante el período de seguimiento. Algunas variables, como la edad o trabajar en el servicio de Infecciosas, se asociaron de forma estadísticamente significativa con la necesidad de seguimiento. Conclusiones: El riesgo de transmisión ocupacional tras un contacto con MbMR podría ser similar a M. tuberculosis, aunque es necesaria mayor experiencia para confirmar este hecho. Es importante un diagnóstico precoz y la existencia de un protocolo para implementar medidas preventivas y de control en este tipo de contactos laborales.