Abstract

A total of one hundred twenty five samples were collected from intensive care unit of two main hospitals in Basrah: 74 clinical samples; Skin, blood, eye, nose, wounds and urine and 51 inanimate samples; bed, wall, instruments and addresses. The total of 334 isolates of bacterial types isolated from various sources as following numbers of isolating and percentages:Staphylococcus aureus 45 (13.47%), Staphylococcus epidermidis 31 (9.28%),  Staphylococcus saprophyticus  18 (5.38%), Staphylococcus xylosus 11 (3.29%), Staphylococcus capitis 7 (2.09%), Streptococcus pyogenes 28 (8.38%), Viridance streptococci 35 (10.47%), Streptococcus pneumonia 12 (3.59%), Pseudomonas aeruginosa 41 (12.27%), Escherichia coli 19 (5.68%),Klebsiella spp 20 (5.98%), Proteus spp 10 (2.99%), Enterobacter 9 (2.69%), Propionibacterium acnes 24 (7.18%), Acinetobacter spp 9 (2.69%) and Corynebacterium spp 15 (4.49%). 31 isolates of S. aureus in percentage 68.89 were isolated as β-lactamase producers, while 14 isolates (31.11%) were β-lactamase non-producers. The prevalence of multiple drugs resistance S. aureus against eight antibiotics were carried in the present study, the resistance against three antibiotics has a biggest percentage (25.8) for β-lactamase producing S. aureus with resistance of eight antibiotics, while resistance of two antibiotics was the predominant mode of β-lactamase non- producing S. aureus in percentage 35.71% with no resistance against more than four antibiotics. The study found that vancomycin, cefotaxime and gentamicin were the most effective antibiotics against β-lactamase producing S. aureus strains isolated from both clinical and inanimate samples of intensive care unit in percentages of resistance (42.22, 44.44 and 44.44%), respectively and tetracycline was the antibiotics that has the highest percentage of resistance (82.22%) against the above strain. While for β-lactamase non- producing S. aureus strains, vancomycin and cefotaxime were also the most effective antibiotics but have the lowest percentages of resistance in comparison to the first above group which recorded (13.33 and 20.0%) of resistance respectively. And tetracycline still the weakest antibiotic has great resistance of 53.82% of isolates. The plasmid profiles in β-lactamase producing and non-producing MDRSA was also determined in this study. The ranges of band molecular weight were between 300 to 600 base pairs with clear main band in 550-570 bp for β-lactamase producing S. aureus. While the ranges of band molecular weight were between 200 to 700 base pairs with clear main band in 450-470 bp and 690-700 bp for β-lactamase producing S. aureus.

Key words: Staphylococcus aureus, antibiotics, β-lactamase, intensive care units.