RESUMEN Se realiza un estudio dinámico lineal del estado tensional de la viga de giro del transportador de descarga del nuevo modelo de cosechadora cañera cubana CCA-5000. Se determinaron los coeficientes dinámicos a partir de la evaluación experimental extensométrica de la cosechadora KTP-23, modelo análogo en su estructura a la CCA-5000. Utilizando el análisis por medio de los elementos finitos se obtiene la distribución del factor de seguridad y las tensiones en la viga para las diferentes combinaciones de cargas actuantes asociadas a una curva de variación dinámica de estas. Se realiza un análisis de los modos de frecuencias para cada estado de carga y se comparan los resultados con las frecuencias de las irregularidades de los terrenos por los que se desplaza la cosechadora, con el objetivo de verificar la aparición o no de grandes amplitudes en las oscilaciones del sistema por el fenómeno de la resonancia. Se realiza la optimización de forma de la viga teniendo en cuenta los resultados anteriores con el objetivo de disminuir el volumen de metal de esta.

ABSTRACT A linear dynamic study of the tensional status of the unloading conveyor´s spin beam in the new model CCA-5000 Cuban sugarcane harvester is carried out. The dynamic coefficients were determined using a strain gauge experimental evaluation of the KTP-23 harvester, which is a similar model in structure to the CCA-5000. A finite elements analysis is used to obtain the safety distribution factor and the tensions in the beam for different load combinations linked to a dynamic variation curve of the loads. Aiming to verify the presence or not of large amplitudes on the system oscillations caused by the resonance phenomenon, an analysis of the frequency modes for each load status is conducted, and the results are compared with the terrain irregularities frequencies on which the harvester moves. Finally, taking into account the previous results, the shape of the beam is optimized in order to decrease its steel volume.

Over 700,000 cases of cholera were reported in Haiti between October 2010 and February 2015. In November 2011, the Cuban Medical Team serving in Haiti established a laboratory-supported sentinel surveillance system for cholera in 10 public hospitals (one in each of Haiti’s 10 departments), to estimate the proportion of hospitalized patients with cholera and detect emergence of new Vibrio cholerae serotypes. Each month, the first ten stool samples collected from patients admitted with acute watery diarrhea were studied in all hospitals involved. Surveillance system findings from November 1, 2011, to October 30, 2012 showed that acute watery diarrhea was caused by V. cholerae serogroup O1 in 45.9% (210/458) of patients: Serotype Ogawa was found in 98.6% of this isolates (207/210) and serotype Inaba in 1.4% (3/210), indicating low circulation level of the latter in Haiti. Continuing laboratory sentinel surveillance of V. cholerae is needed to monitor the spread of the disease and prevent and contain outbreaks, particularly of new serotypes. It is important to ensure that these findings are systematically integrated with data available to MSPP from other surveillance sources.

The present study describes the behavior of meningococcal disease in 86 cases notified with isolation of Neisseria meningitidis in Cuba from 1998-2007, through spatial and temporal distribution of cases, phenotypic characterization of isolated strains and identification of some host risk factors that may affect phenotypic switching of strains. Percentages and the rate of changes of the strain phenotypic structure with different criteria were calculated. Children under one year old (30.2%) and meningitis (76.7%) were predominant. Case-fatality rate was 15.1%. The 58.1% of cases were ill with the same vaccine strain phenotype (B:4:P1.19,15). Phenotypic changes were detected in 41.9% of the isolates, mainly in children of 5-9 years old who live in western and central regions. Children that fell ill in July, September, December and April and live in Matanzas, Havana and Villa Clara provinces were associated to phenotypic switching of strains.

En la presente investigación se describió el comportamiento de la enfermedad meningocócica en 86 casos notificados con aislamiento de Neisseria meningitidis en Cuba, entre 1998-2007, a través de la distribución espacial y temporal de los casos, la caracterización fenotípica de las cepas aisladas y la identificación de algunos factores de riesgo del hospedero que pudieran incidir en su cambio fenotípico. Se calcularon los porcentajes y el índice de cambio de la estructura fenotípica del meningococo con diferentes criterios. Predominó el grupo de pacientes menores de un año (30,2%) y la forma clínica meningítica (76,7%). La letalidad fue de 15,1%. Enfermó con el mismo fenotipo de la cepa vacunal (B:4:P1.19,15) el 58,1% de los casos. Se detectaron cambios fenotípicos en el 41,9% de las cepas aisladas, principalmente en niños entre 5-9 años (2001 y 2007), residentes en la región occidental y central del país. Los que enfermaron en julio, septiembre, diciembre y abril y residían en las provincias de Matanzas, La Habana y Villa Clara, se asociaron con el cambio fenotípico de las cepas.

Invasive Meningococcal Disease (IMD) is a worldwide health problem. In Cuba, vaccination against meningococcal B-C has been carried out since 1989. The study aimed at describing the epidemiology of IMD in Cuba from 1983 to 2006 and at contributing to the immunization strategy. A descriptive and analytical study was carried out. Epidemiological data was obtained from the National Surveillance System at the Institute "Pedro Kourí". More than 1 000 cases were reported in 1986 and the overall incidence was above 10/100 000 inhabitants. Since 1989 a remarkable and continuous decline in the incidence was observed. In the last nine years a strong association of IMD to boarding school students (OR=9.4; confidence interval 95%: 5.1-17.4), recluses (OR=5.9; CI 95%: 1.5 -24.3) and day students (OR=3.9; CI 95%: 2.8-5.6) was observed. Housewife (OR=4.9; CI 95%: 1.9-12.4) and pensioned (OR=4.5; CI 95%: 1.2-16.8) showed association with mortality. Previous vaccination was a protective factor against morbidity (OR=0.6; CI 95%: 0.4-1.0) and mortality (OR=0.4; CI 95%: 0.2-0.9) by IMD. Neisseria meningitidis B4:P1.15 was the main circulating strain. Incidence of IMD declined markedly in Cuba by using group BC strain-specific meningococcal vaccine.

La enfermedad meningocócica invasiva (EMI) es un problema de salud mundial. En Cuba, la vacunación antimeningocócica BC se ha llevado a cabo desde 1989. El propósito del presente trabajo fue describir la epidemiología de la EMI entre 1983-2006 y contribuir a la estrategia de prevención. Se realizó un estudio descriptivo y analítico de todos los casos confirmados y registrados. Los datos se obtuvieron del Sistema Nacional de Vigilancia en el Instituto «Pedro Kourí». En 1986 se registraron más de 1 000 casos de EMI con una incidencia de 10/100 000 habitantes. Desde 1989 se observó un notable y continuo descenso de la incidencia. En los últimos 9 años se observó una fuerte asociación en la ocurrencia de casos con estudiantes de régimen interno (OR=9,4; Intervalo de Confianza 95%: 5,1-17,4), reclusos (OR=5,9; IC 95%: 1,5-24,3) y estudiantes externos (OR=3,9; IC 95%: 2,8-5,6). Mostraron asociación con la mortalidad las amas de casa (OR=4,9; CI 95%: 1,9-12,4) y los jubilados (OR=4,5; CI 95%: 1,2-16,8). La vacunación previa mostró ser un factor protector para la morbilidad (OR=0,6; CI 95%:0,4-1,0) y la mortalidad (OR=0,4; CI 95%: 0,2-0,9). El principal fenotipo circulante de Neisseria meningitidis fue B4:P1.15. La incidencia de EMI se redujo notablemente en Cuba a partir del uso de la vacuna antimeningocócica específica del grupo B.

A method to determine the minimum inhibitory concentration for leptospiras was developed, since there is not a standard method to measure it at the international level. Reference strains from the pathogenic complex L. interrogans and L. biflexa were used against penicillin, cyprofloxacine, chloramphenicol, rifampicine and tetracycline. The minimum inhibitory concentration was defined as the lowest concentration of antibiotic where it was observed the inhibition of the bacterial mobility by direct examination in dark field. Ranges for penicllin were from 0.095 to 152 μg/mL, for tetracycline from 0.156 to 3.13 μg/mL, for chloramphenicol, from 0.08 to 12.52 μg/mL, for rifampicine from 0.08 to 1.56 μg/mL, and for cyprofloxacine from 0.15 to 2.4 μg/mL. The antibiotics that showed the lowest values were cyprofloxacine, rifampicine and tetracycline, whereas the most elevated value was obtained against chloramphenicol and penicllin. The strains from the serogroups circulating more frequently in Cuba were used in this research. This study will allow in a near future to determine the antimicrobial susceptibility in autochthonous strains isolated from patients with Leptospirosis at the national level.

Se desarrolló un método para determinar la concentración mínima inhibitoria para las leptospiras, porque internacionalmente no existe un método estándar para medirla. Se utilizaron cepas de referencia, pertenecientes al complejo patogénico L. interrogans y L. biflexa frente a la penicilina, la ciprofloxacina, el cloranfenicol, la rifampicina, y la tetraciclina. La concentración mínima inhibitoria, fue definida como la menor concentración del antibiótico donde se observó la inhibición de la movilidad bacteriana por examen directo en campo oscuro. Los rangos fluctuaron para la penicilina desde 0,095 hasta 12-52 μg/mL, para la tetraciclina desde 0,156 hasta 3,13 μg/mL, para el cloranfenicol desde 0,08 hasta 12,52 μg/mL, para la rifampicina desde 0,08 μg/mL y hasta 1,56 μg/mL y para la ciprofloxacina desde 0,15 hasta 2,4 μg/mL. Los antibióticos que presentaron los valores más bajos fueron la ciprofloxacina, la rifampicina y la tetraciclina y el valor más elevado se obtuvo frente el cloranfenicol y la penicilina. En esta investigación fueron empleadas las cepas de los serogrupos que circulan más frecuentemente en Cuba. Este estudio permitirá en un futuro cercano, determinar la susceptibilidad antimicrobiana en cepas autóctonas aisladas de pacientes con leptospirosis, al nivel nacional.

Four methods (chromogenic, acidimetric, inhibition, and iodometric) for demonstration of the beta-lactamase production by 70 isolates of Neisseria gonorrhoeae, were evaluated in Cuba. There was 100% correlation between all beta-lactamase methods and the standardized penicillin dilution susceptibility test for penicillinase-non-producing N. gonorrhoeae. For penicillinase-producing N. gonorrhoeae strains, there was a perfect correlation between the chromogenic method and penicillin susceptibility testing, but one and two strains failed to give a positive result for beta-lactamase with the inhibition/acidimetric and the iodometric methods, respectively. There was a high concordance between the chromogenic method, considered as gold standard and the rest of penicillinase tests evaluated: Kappa Index (KI) = 0.98 for inhibition/acidimetric methods and KI = 0.97 for the iodometric method. The four methods evaluated were accurate, reproducible, easily readable, economical, and ease to use for screening primary isolates of N. gonorrhoeae in Cuba. We recommended the use of the inhibition method, when testing the penicillinase activity in gonococcal isolates in provincial and municipal reference laboratories.

5 methods of utilization of sugars were evaluated in 25 strains previously identified as N. gonorrhoeae: CTA agar, modified CTA agar, gelatin starch agar, Mueller Hinton agar plus bromotimol blue and rapid method. 100 % of the strains of N. gonorrhoeae were identified by the CTA and rapid methods, whereas 96 % were identified by the modified CTA and gelatin starch agar methods. No strain of gonoccocus was identified by the Mueller Hinton agar method plus bromotimol blue. The cystine tripticase agar medium (CTA) is the elective method to confirm the isolates of Neisseria gonorrhoeae. As it is mainly made by U.S. companies, it is difficult for Cuba to acquire it. The gelatin-starch agar.method and the rapid method are useful alternative of the CTA medium, so their use is proposed in this paper.

Se evaluaron 5 métodos de utilización de azúcares en 25 cepas identificadas previamente como Neisseria gonorrhoeae: agar CTA, agar CTA modificado, agar gelatina almidón, agar Mueller Hinton más azul de bromotimol y método rápido. Por los métodos de CTA y rápido fueron identificadas 100 % de las cepas de N. gonorrhoeae, mientras que por los métodos de CTA modificado y agar gelatina almidón fue 96 %. Ninguna cepa de gonococo fue identificada por el método de agar Mueller Hinton más azul de bromotimol. El medio de agar cistina tripticasa (CTA), constituye el método de elección para confirmar los aislamientos de Neisseria gonorrhoeae; es elaborado fundamentalmente por compañías norteamericanas, por lo que su adquisición en Cuba resulta difícil. Los métodos de agar gelatina almidón y rápido constituyen alternativas útiles del medio CTA, por lo que su uso se propone en este trabajo.

The susceptibility to penicillin of 111 Neisseria meningitidis strains was assessed by the agar-dilution procedure and serosubtypes were determined by a whole-cell enzyme-linked immunoassay using monoclonal antibodies reagents. Thirty-five isolates showed reduced sensitivity to penicillin (MIC > or = 0.1 mg/l and <= 1 mg/l) and no resistant strains were detected. The most common phenotype was B:4:P1.15 (77.5%) and a rising trend of non-typeable and non-subtypeable strains was detected. The increase in levels of minimal inhibitory concentrations of meningococci to penicillin gives cause for concern and the increase in non-typeable and non-subtypeable isolation demand the use of molecular biology techniques for their typing.

The conjunctivitis produced by Neisseria gonorrhoeae is the less frequently reported clinical form of gonococcal infection. We aim to phenotypically characterize N. gonorrhoeae isolated from conjunctivae sites. A total of six cases of this disease were notified in the Camagüey province, Cuba. All the strains isolated were penicillin-producing, showed the serogroup WI and exhibited the same antimicrobial susceptibility pattern and plasmid profile (2.6-3.2-24.5). The results contribute to the characterization of N. gonorrhoeae strains circulating in our environment.