ABSTRACT
Background: Recent studies have shown that wastewater is contaminated by salmonella sp., pathogenic antibiotics-resisting bacteria. Using wastewater in periurban agriculture in Abidjan is likely to be the source of food-borne diseases such as salmonellosis. However, what we know about these resistant salmonella spp. in wastewater is limited in the country. Aims: This study aims to establish the susceptibility profile of Salmonella spp., isolated from wastewater to antibiotics and to antimetabolite commonly used by medical practitioners. Study Design: Spatio-temporal variation was taken into account. Place and Duration of Study: The study took place from August 2008 to January 2009 at the main campus of the university of Cocody in Abidjan. Methodology: Sampling was done on a weekly basis. Wastewater samples were collected at four different sewers in the campus area. Salmonella sp was isolated by a standard method of laboratory. The resistance of these isolated species to antibiotics was determined according to the disk diffusion method of Kirby-Baeur. The serotypes of salmonella were identified with the Kauffman-White table Results: Five serotypes of eleven strains, which consist of 4 Hato, 3 Farmsen, 2 Derby, 1 Essen and 1 Ovonmouth, were isolated and tested in order to determine their resistance to antibiotics. Amongst the various classes of antibiotics, high resistance was found to sulfonamid (100%), followed by cefotaxime (46.67%) and tetracycline (9.1%). Ampicillin, amoxicillin and clavulanic acid, gentamicin, kanamycin, amikacin, ciprofloxacine, nalidixic acid and chloramphenicol had a high potentiality: their efficacity in the elimination of the Salmonella sp was proved at a level of 100%. Although the majority of strains tested (85.94%) were eliminated by the antibiotics, the serotypes Derby, Hato and Farmsen showed resistance. Conclusion: The Wastewater in the area of the main campus of the University of Cocody contains the antibiotic-resisting strains of salmonella sp. In spite of the fact that the efficacity of some antibiotics in the elimination of Salmonella sp. is proved, the resistance of these strains to third generation of cephalosporin and sulfamid is worrisome. Further studies should be carried out to determine the effects of this antibiotic-resisting salmonella species on humain health.
ABSTRACT
OBJECTIVES: We established a Wistar rat model of asthma caused by toluene diisocyanate (TDI) exposure, and investigated the relationship between TDI exposure concentrations and respiratory hypersensitivity, airway inflammation, and cytokine secretions in animals, to better understand the mechanism of TDI induced occupational asthma. METHODS: Wistar rats were exposed to two different concentrations of TDI vapor four hours a day for five consecutive days. Bronchoalveolar lavage (BAL) was performed, and differential leucocytes from the BAL fluid were analyzed. Lung histopathological examination was carried out to investigate the inflammatory status in the airways. Production of cytokines interleukin (IL)-4 and IL-5 productions in the BAL fluid in vivo was determined with enzyme-linked immunosorbent assay kits. RESULTS: The TDI-exposed rats exhibited greater airway hypersensitivity symptoms than the control rats. The BAL differential cell count and lung histopathological examination demonstrated that inflammation reactions were present in both the central and peripheral airways, characterized with marked infiltration of eosinophils in the TDI-exposed rats. The cytokine assay showed that IL-4 and IL-5 were predominantly produced in the BAL fluid in vivo. CONCLUSIONS: These findings imply that TDI exposure concentrations may greatly affect the occurrence and extent of inflammatory events and that Th2 type cytokines may play an important role in the immunopathogenesis of TDI-induced occupational respiratory hypersensitivity.