Two Dimensional (2D) circular Photonic Crystal Ring Resonator (PCRR) based Add Drop Filter (ADF) is designed and the impacts of rod shape with its filling fraction is examined to evaluate the performance of the filter. The ADFs are devised separately using rods of circular, hexagonal and square shape in square lattice PC. For various values of rod’s cross sectional dimension and shape, the resonant wavelength, coupling efficiency, dropping efficiency, Q factor and passband width of the designed filters are investigated through simulation. The calculated filling fraction of a square, circular and hexagonal rods in the lattice structure is 11.9006 × 10-12 sq.m, 13.1134 × 10-12 sq.m and 15.16 × 10-12 sq.m and their respective resonant wavelength is 1494 nm, 1504 nm and 1520 nm. It is observed that there is 1 nm wavelength shift to longer wavelength while increasing the overall filling fraction by 0.1233 × 10-12 sq.m. From the simulated results, it is observed that the circular and hexagonal rods based ADF impart better performance than square rod based ADF.

OBJETIVES: To determine the distribution and antibiotic susceptibility patterns of nosocomial pathogens in the Intensive Care Unit (ICU) at the University Hospital of the West Indies (UHWI). METHODS: A retrospective review of the laboratory records of all ICU patients from 2002-2004 was done. All organisms isolated from blood, urine, sputum, wound swabs and CVP tips were recorded. Sensitivity reports for organisms isolated in 2004 were also obtained. Results were analysed according to source of isolates and type of infection. RESULTS: Gram-negative organisms account for the majority of ICU isolates and show resistance to multiple antibiotics. The common Gram negative pathogens in the ICU are Pseudomonas aeruginosa, Acinetobacter spp and Stenotrophomonas maltophilia while the common Gram positive nosocomial organisms are Group D Streptococcus and coagulase negative Staphylococcus. CONCLUSION: The organisms isolated in the ICU at the UHWI are similar to those isolated in many ICUs all over the world. Surveillance data are necessary to monitor nosocomial pathogens and their resistance patterns to guide empirical antibiotic therapy.

OBJETIVOS: Determinar la distribución y los patrones de susceptibilidad antibiótica de los patógenos nosocomiales en la Unidad de Cuidados Intensivos (UCI) del Hospital Universitario de West Indies (HUWI). MÉTODOS: Se realizó una revisión retrospectiva de las historias clínicas de laboratorio de todos los pacientes de la UCI de 2002-2004. Se registraron todos los organismos aislados a partir de sangre, orina, esputo, hisopos de heridas, y las puntas de catéteres de PVC. Los resultados fueron analizados de acuerdo con las fuentes de los aislados y el tipo de infección. RESULTADOS: Los organismos gramnegativos representan la mayor parte de aislados de la UCI y muestran resistencia a múltiples antibióticos. Los patógenos gramnegativos comunes en la UCI son Pseudomonas aeruginosa, Acinetobacter spp y Stenotrophomonas maltophilia mientras que los organismos nosocomiales grampositivos comunes son Group D Streptococcus y coagulase negative Staphylococcus. CONCLUSIÓN: Los organismos aislados en la UCI en el HUWI son similares a los aislados en muchas UCIs en todo el mundo. La información sobre la vigilancia es necesaria a fin de monitorear los patógenos nosocomiales y sus patrones de resistencia para guiar la terapia antibiótica empírica.