Thirty five bacterial isolates were collected from urine and blood samples of 20 patients, before and after endoscopy examination, in new Surgical Hospitals, Zagazig University Hospital, Zagazig, Egypt. Antibiotic susceptibility profile of purified bacteria revealed four multi-resistant strains identified as S. aureus Zag11, P. aeruginosa Zag60, E. coli Zag126 and S. epidermidis Zag128. The four selected bacteria were subjected to some disinfectants (glutaraldehyde, hydrogen peroxide, P3-oxonia and Orthophthaladehyde) at different concentrations and different exposure times. It was observed that 10 min were enough to inhibit growth of tested pathogenic bacteria in case of (8% H2O2 & 0.55% orthophthaladehyde) while completely inhibition was recorded after 15min in case of ( 2.2% glutaraldehyde, 70% ethanol and 0.45% P3-oxonia). Sterile urinary tract endoscopy was artificially contaminated with mixture (1:1:1:1:1:1) of six clinical pathogenic bacterial strains pararil with the four tested bacterial strains. Upon exposing the contaminated endoscope to different chemical disinfectants; 8% hydrogen peroxide and 0.55% Orthophthalaldehyde inhibited after 30 min exposure while 2.

Extracellular proteins of pathogenic bacteria are main contributors of pathogenesis and are involved in bacterial virulence. These proteins have a range of biological functions ranging from host cell toxicity to more subtle alterations of the host cell for the benefit of the invader (Wooldridge,2009).The virulence factors of pathogenic bacteria are divided into several groups on the basis of the mechanism of virulence and function. Of the important ones are secretary proteins such as toxins and enzymes (Wu et al., 2008). Among these pathogenic bacteria are genus Bacillus and Staphylococcus which cause a wide variety of diseases through production of their toxins on several substrates, among these substrates "food" and this resulting in food poisoning. Polymerase chain reaction (PCR) methods offer a sensitive and specific detection of pathogens and can discriminate virulent bacteria from a virulent members of the same species as well(Olsen, 2000). In the last 10 years, many authors have proposed the use of PCR for the detection of food-borne pathogens to replace the time-consuming culture-based classical techniques (Gravet et al., 1999 and Miethke et al., 1992).