الفهرس 
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Abstract
ABSTRACT
Nosocomial infections are a worldwide healthcare and public health problem. The most serious problem with antibiotic resistance is that some bacteria have become resistant to almost all of the easily available antibiotics.
A total of seventy isolates of bacteria were collected during the period from March to September 2013 from Zagazig University hospital’s intensive care units (ICUs) from patients, tools, air, floor, wall and nursing cubicles. The selected isolates include 33 (56.9%) isolates from males and 25 (43.1%) isolates from females whose ages ranged between 25 to 85 years.
The most effective antibiotic was imipenem followed by amikacin, ceftazidime, ciprofloxacin and tobramycin, respectively. On the other hand 61.4% of bacterial isolates were resistant to nitrofurantoin while 55.7% and 52.9% of bacterial isolates were resistant to sulphamethoxazole/trimethoprim and cefuroxime, respectively.
The multi-drug resistant (MDR) bacterial isolates (33 isolates) were selected to be identified. Different morphological, physiological and biochemical tests were conducted for identification of bacterial isolates. According to the keys of different identification protocols the tested isolates divided into four groups namely, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. Our study documented a predominance of Gram-negative organisms in nosocomial infections of ICU .
Escherichia coli found to be the most frequent pathogen within MDR isolates cased nosocomial ICU infections followed by Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae respectively.
The MICs and MBCs of four antibiotics (Imipenem, Amikacin, Ceftazidime and ciprofloxacin against the most resistant isolates were determined by using the standard broth dilution technique.
The effect of different concentrations of common antiseptics and disinfectants (cyteal, savlon, betadine, dettol, chlorox, hydrogen peroxide and ethyl alcohol) on the most resistant bacterial strains was studied.
Of all extracts, the ethanolic extract of Rosemary was the most active one with inhibition zones diameter ranged between 15mm-23mm and Marjoram caused inhibition zones ranged between 13mm to 21mm. Followed by Lemon grass, Chamomile and Pepper mint respectively.
Whereas, the aqueous extract of marjoram was the most active of all tested aqueous extracts followed by rosemary and pepper mint respectively, while aqueous extracts of chamomile and lemon grass had no effect on tested bacteria.
The tested MDR isolates showed resistance to essential oils in low concentrations. Of all essential oils, the essential oils of Clove, Rosemary and Marjoram, respectively was the most active oils. Followed by Thyme, Black seed, Lemon grass, Pepper mint, Fennel, Chamomile and Anise respectively.
The tested MDR isolates showed resistance to honey in low concentrations (50% and 60%) and honey had moderate to weak effect against the selected multi resistant bacterial isolates in all tested concentrations. The most susceptible bacteria to honey were S. aureus (17) and P. aeruginosa (55) respectively, while the least susceptible were E. coli (59) and K. pneumoniae (42) respectively. Clover honey showed in most cases higher antibacterial activity than cotton honey.
Generally Gram positive bacteria are more susceptible to antibiotics, antiseptics, disinfectants and natural antimicrobials than Gram negative bacteria and P. aeruginosa was generally found to be the highest resistant bacteria to antiseptics, disinfectants and natural antimicrobials.
Plasmid profile of the most resistant clinical isolate, Pseudomonas aeruginosa (55) were carried out. After incubation at 37oc for 24hr recorded no change in plasmid and its profile at lane 3&4 showed three bands at 23.130bp, 1221bp and 72bp compared with incubation at 43oc (plasmid curing) which showed complete removal of plasmid bands and the tested bacteria become more sensitive to antibiotics.