The delaved-type hypersensitivity (DTH) reaction (an in vivo manifestation of cell-mediated immunity) was studied in rainbow trout (Oncorhynchus mykiss) exposed to sealworm Pseudoterranova decipiens infections. Test fish immunized with sealworm extract and live intact worms, were compared with control fish which received either phosphate-buffered saline (negative control) or nonhomologous cestode or nematode antigens (positive control). Test fish immunized with sealworm extract produced a typical DTH reaction to live sealworm, challenge. The DTH reaction was similar to that in mammals and showed lymphoid and mononuclear cell infiltration. The electron microscopical studies revealed the presence of activated macrophages and plasma cells in the reaction zone. The specific response, following immunization with homologous antigens, supports the existence of T-cell function with anamnesis in rainbow trout exposed to sealworm antigens. However, when the test fish were immunized with live sealworms and later challenged with live sealworms, the secondary response was poor and showed no difference from controls and naive fish.

7991. Tissue response of fish to invasion by larval Pseudoterranova decipiens (Nernatoda; Ascaridoidea). Can. 1. Fish. Aquat. Sci. 48: 1623-1 628.The histopathoisgy of Pseudoterranova decipiens (L,) in experimentally infected rainbow trout (Oncorhynchus rnykiss) and naturally infected Atlantic cod (Cadus rnarhua) was similar. The chronic granulomatous inflammatory reaction included polymorphonuclear neutrsphils, macrophages, lymphocytes, epithelioid cells, and fibroblasts. Giant cells were also found but only in the experimentally infected rainbow trout. Mature capsules around the larvae consisted of an inner layer, composed of macrsphages which underwent epithelioid transformation and later gradually degenerated, and an outer layer, composed of fibroblasts and collagen fibres. A layer of Iipofuscin was adjacent to the parasite in older cod infections but this was absent in all of the newly formed capsules in the experimentally infected rainbow trout. L'histopathologie de Pseudoterranova decipiens fL,) etait similaire chez des truites arc-en-ciel (Oncorhynchus rnykiss) infestees experirnentalement et chez des morues franches (Gadus morhua) infestbes naturellera~eest. La reaction inflamrnatoire chronique granulomateuse presentait des neutrophiles po~ymorphsnucl~aires, des macrophages, des lymphocytes, des cellules epitheiioi'des et des fibroblastes. On a aussi trouve des cellules geantes, mais seulement chez Oes truites arc-en-ciel infestees experimentalement. Les capsules rnirres qui entouraient les larves se csmpssaient d'une coucke interne, constituee de macrsphages qui subissaient une transformation 6pithelioaide puis deggneraient graduellement par la suite, et une couche externe, constituk de fibroblastes et de fibres de collag&ne, Une couche de lipofuscine ktait adjacente au parasite dans les infections anciennes chez les morues, mais elle ktait absente dans tsutes les capsules nouvellement formees chez les truites arc-en-ciel infestkes expesimentalement.

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Abstract:Staphylococcus aureus is one of the important causes of community acquired and hospital acquired infections worldwide. Methicillin resistant Staphylococcus aureus is one of the major antibiotic resistant organisms. The present study was undertaken to determine the antibiotic sensitivity of Staphylococcus aureus isolates from various clinical samples and to evaluate the possible presence of MRSA, VISA (vancomycin intermediate Staphylococcus aureus) and VRSA (vancomycin resistant Staphylococcus aureus). A total of 120 isolates of S. aureus which were isolated from various clinical samples were tested for methicillin resistance using the oxacillin disc diffusion test (1µg) and cefoxitin disc diffusion test (30µg). All isolates were subjected to minimum inhibitory concentration (MIC) testing with agar dilution method according to the CLSI (Clinical Laboratory Standards Institutes) guidelines. Disc diffusion method was also used to determine the susceptibility of strains to common antibiotics. 64(53.3%) isolates were found to be MRSA by the cefoxitin disc diffusion method and 63(52.5%) isolates were found to be MRSA by oxacillin disc diffusion method. No VISA&VRSA isolates were detected by using the MIC agar dilution method. MRSA isolates were also highly resistant to other antibiotics that were tested.

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