Detection of virulence factors in α-haemolytic Escherichia coli strains isolated from various clinical materials

ABSTRACTIn total, 201 α-haemolytic Escherichia coli isolates from various clinical materials (urine samples and vaginal and rectal swabs) were examined by PCR for the presence of genes for the virulence factors α-haemolysin (hly), cytotoxic necrotising factor type 1 (cnf1), P-fimbriae (pap), S/F1C-fimbriae (sfa/foc), aerobactin (aer) and afimbrial adhesin (afaI). Among vaginal isolates, 96% were positive for cnf1, compared with 80% of urine strains (p 0.02) and 63% of rectal strains (p 0.0001). Similarly, sfa/foc-specific DNA sequences were found in 97% of vaginal isolates compared with 75% of rectal strains (p 0.004). The afa1 and aer genes were associated more with rectal a-haemolytic E. coli strains than with extra-intestinal isolates. The results suggested that CNF1 and/or S/F1C-fimbriae contribute to colonisation and persistence of a-haemolytic E. coli strains in the vaginal environment

Corrosion Behaviour Correlation of the Secondary Aluminium Casts in Natural Atmosphere and Laboratory Conditions

The secondary aluminium alloys are very important material in actual industry from economic and ecological point of view. The secondary aluminium used for production of casts, however, contains some elements, i.e. iron, – affecting physical, chemical and mechanical behaviour. The subject of our investigation has been corrosion behaviour in natural atmosphere of the hypoeutectic AlSi7Mg0.3 cast alloys with various content of iron, because the Fe content affects not only mechanical properties but corrosion resistance, as well. Three types of the AlSi7Mg0.3 cast alloys were exposed for 9 months in natural atmosphere and the measure of their degradation by corrosion was found by determination of the weight loss and the light microscopy. In addition, a scanning electron microscopy (SEM) analyses and evaluation of surface changes were used. The corrosion behaviour in natural atmosphere was compared to results of the carried out electrochemical and exposure laboratory experiments in chloride solutions