A note on the incidence and antibiotic resistance of Staphylococcus aureus isolated from meat and chicken samples.

One hundred and fifty samples of raw calf/lamb meat samples (mince and chunks) and chicken parts (giblets, carcass) were analysed for the presence of Staphylococcus aureus. Eighty S. aureus strains were isolated and identified. Resistance of the strains to methicillin and other antibiotics was determined by the Kirby-Bauer disc diffusion test. The overall methicillin resistance rate for S. aureus was 67.5%. Of S. aureus strains, 87.5% were resistant to bacitracin. A high prevalence of penicillin G resistance was detected for S. aureus (53.8%). Few of the strains were resistant to erythromycin (7.5%). All strains were susceptible to vancomycin, sulbactam-ampicillin, ciprofloxacin and cefaperazone-sulbactam. This study confirmed the presence of S. aureus, especially antibiotic-resistant strains, in the foods examined, indicating poor sanitary conditions during processing which may create a health risk for consumers.

The protective effect of taurine against gentamicin-induced acute tubular necrosis in rats.

BACKGROUND: Taurine, which is the major intracellular free beta-amino acid, is known to be an endogenous antioxidant and a membrane-stabilizing agent. In this study, we wished to know whether taurine altered the concentration of gentamicin in kidney tissue and could protect against gentamicin-induced acute proximal tubular injury. METHODS: Wistar albino rats of both sexes were assigned to three groups, which all received one of the following daily intraperitoneal injections for 8 days: (i) 0.9% sodium chloride (NaCl) alone at the same volume as gentamicin treated rats (group C; n=8); (ii) 100 mg/kg/day gentamicin alone (group G; n=8, four male, four female); or (iii) 100 mg/kg/day gentamicin plus 7.5 ml/kg/day taurine (group G+T; n=9, five male, four female). Urine was collected for 24 h for the determination of urine volume and creatinine. Intracardiac blood was collected for blood urea nitrogen (BUN) and serum creatinine determination. The kidneys were removed, weighed, and the left kidneys were subjected to biochemical analysis for the determination of thiobarbituric acid-reactive substance (TBARS) and lactate levels, and glutathione peroxidase (Gpx) and superoxide dismutase (SOD) activities. The right kidneys were divided vertically in half. The upper halves were used for histopathological examination, by light and electron microscopy. The lower halves were used to detect the gentamicin concentration within the kidney tissue, by high-performance liquid chromatography (HPLC). Changes in body weight and normalized kidney weight were recorded. RESULTS: Taurine treatment reduced gentamicin-induced increases in serum creatinine, 24 h urine volume, BUN and tissue lactate and TBARS levels (0.57+/-0.02 vs 1.06+/-0.08 mg/dl, P<0.001; 9.00+/-1.46 vs 20.9+/-2.73 ml, P<0.001; 25.3+/-1.87 vs 54.1+/-6.99 mg/dl, P<0. 001; 2.56+/-0.10 vs 3.44+/-0.08 micromol/g wet tissue, P<0.001; and 66.4+/-3.41 vs 79.5+/-5.07 nmol/g wet tissue, P>0.05, respectively). Taurine reduced the accumulation of gentamicin within the kidney tissue (233+/-29 vs 494+/-93 microg/g wet tissue, P<0.05). Taurine treatment also prevented body weight loss due to gentamicin administration (17.8+/-1.64 vs -10.0+/-7.08 g, P<0.01) and normalized reduced Gpx and SOD activities (3.46+/-0.16 vs 2.37+/-0. 15 U/g wet tissue, P<0.01; and 15577+/-377 vs 12662+/-577 U/g wet tissue, P<0.01, respectively). Light microscopic examination of the renal tissues from gentamicin-treated rats revealed severe histopathological changes, whereas specimens obtained from taurine-treated rats revealed only mild changes. This finding was supported by electron microscopic examination. CONCLUSIONS: Our observations suggest that taurine treatment attenuates the accumulation of gentamicin within kidney tissue and counteracts the deleterious effect of gentamicin on renal tubular function. They may have potentially important clinical implications.

The effect of antioxidant vitamins E and C on lipoperoxidation of erythrocyte membranes during hyperbaric oxygenation.

The aim of this research was to determine whether administration of an antioxidant vitamin combination can reduce oxidative damage in erythrocytes induced by hyperbaric oxygenation (HBO). Malonyldialdehyde (MDA) levels and osmotic fragility ratios in erythrocytes of 28 rats were compared in group A [control], group B [Vitamin (E + C)], group C [HBO] and group D [HBO + Vitamin (E + C)]. HBO was applied at a pressure of 2.8 atmospheres absolute (ATA), 1 hour daily, for 45 days in groups C and D. Administration of alpha-tocopherol acetate (40 mg/kg) and Na-ascorbate (200 mg/kg) was initiated 3 days before the start of HBO exposures and administered intraperitoneally 3 times a week for 45 days. MDA levels and osmotic fragility ratios were significantly higher in group C than in groups A and B (p < 0.05 for all). Significant decreases in MDA levels and osmotic fragility were observed in group D compared with group C, although these parameters were still significantly higher than in controls (p < 0.05 for all). Prolonged HBO resulted in oxidative damage indicated by significant increases in MDA levels and osmotic fragility ratios, which were reduced by concomitant vitamin (E + C) administration.

L-carnitine treatment improves brain stem auditory evoked potentials in diabetic rats.

The effect of L-carnitine (LC) on brain stem auditory evoked potentials (BAEP), was examined in alloxan-diabetic rats. LC (200 mg kg-1, i.p., once daily) was given to diabetic rats starting from the third week after the induction of diabetes, lasting for 4 weeks. Age-matched non-diabetic rats served as controls. The latency of wave I and interpeak latency I-IV were measured once weekly. Diabetes-induced deficits in BAEP latencies (p < 0.05, diabetics vs non-diabetic controls) were improved after LC treatment (p < 0.05, LC-treated diabetic rats vs non-diabetic controls). Weight and glucose levels were not influenced by LC treatment. Our results suggest that LC had beneficial effects on diabetic central neuropathy but these effects are not associated with the regulation of glycaemia in alloxan-diabetic rats.

Effects of dexfenfluramine on glucose drinking and glucose-conditioned flavour preferences in rats: taste versus post-ingestive conditioning.

A comparison was made of the effects of dexfenfluramine (DF, 3-10 mg kg-1) on intake of and conditioning with glucose solutions varying in orostimulant properties (taste) and post-ingestive actions (calories), in rats. First, sham-feeding, using gastric-fistulated rats, was performed to assess the orostimulant properties of the solutions. Then, two experiments were done. In the first experiment, we examined the effects of DF, given at doses of 13 and 10 mg kg-1, on the intake of two glucose solutions having different orostimulant properties and different caloric values. The solutions were a mix of 1% glucose plus 0.125% saccharin (low caloric, more orostimulant), and 4% glucose (high caloric, less orostimulant). At doses of 10 mg kg-1, DF administration markedly reduced intake of both solutions (P < 0.05 vs Control Group, respectively). In second experiment, we examined the effects of DF (10 mg kg-1) on flavour preference conditioning in two parts. In the first part of the experiment, rats consumed two distinctively flavoured solutions having equal orostimulant properties but different caloric value for a conditioning period of 16 days. The solutions were a mix of 1% glucose plus 0.125% saccharin (low caloric), and 6.1% glucose (high caloric). At the end of the conditioning period, the flavour paired with ingestion of more calories was subsequently preferred (P < 0.05 vs low caloric glucose-saccharin mix). DF, when given during and after the conditioning period, attenuated this flavour-calorie conditioning (P < 0.05 vs Control Group). In the second part of the experiment, rats were conditioned with flavours associated with a mix of 20% glucose plus 0.4% citric acid and 20% glucose solutions. These solutions were equally caloric but differed in orostimulant properties. The flavour paired with better orostimulant properties was subsequently preferred (P < 0.05 vs less orostimulant glucose-citric acid mix). DF, when given during and after the conditioning period, also attenuated this flavour-flavour conditioning (P < 0.05 vs Control Group). These results suggest that DF may impair flavour preference learning.