Abstract
Twelve final effluent samples from four hospitals namely Al-Ansar, Al-Miqat, Al-Zahraa and Al-Dar in Al-Madina Al-Munnawara were collected in spring of 2007 and screened for bacterial counts. Gram-negative rods belonging to 21 different species and 13 genera represented the main bulk (65.2%) out of the 359 bacterial isolates followed by Gram-positive rods (31.8%) and Gram positive cocci (3.1%). The most common isolates were belonging to Escherichia coli (32.05%) followed by Enterobacter cloacae (17.9%). The 234 identified Gram-negative rods isolates were tested for their susceptibility for seven antibiotics at the commonly tested concentrations in hospitals and higher concentrations of the same antibiotics. Gentamicin was the most effective antibiotic, as only 2.6% of these isolates were resistant to 10 mu g/ml, while 2.1% were resistant up to 256 mu g/ml. The least effective antibiotic tested was sulphamethoxazole, as 82.9% of the isolates were resistant to 25 mu g/ml of this antibiotic, while 62.8% were resistant to 1024 mu g/ml. The second less effective antibiotic was ampicillin.