Prevalence of -Lactamase-Producing and Non-Producing Staphylococcus Aureus associated with Patients in Intensive Care Units

A total of 125 samples were collected from intensive care units (ICUs) of two main hospitals in Basrah: 74 clinical samples including Skin, blood, eye, nose, wounds, and urine and 51 inanimate samples including bed, wall, instruments, and addresses. A total of 334 isolates of bacterial types were isolated from various sources, including the following number of isolates and their 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%), Viridans streptococci 35 (10.47%), Streptococcus pneumoniae 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%). A total of 31 isolates of S. aureus (68.89%) were -lactamase producers, while 14 isolates (31.11%) were -lactamase non-producers. The prevalence of multidrug resistance of S. aureus against eight antibiotics was carried out in the present study. The resistance against three antibiotics had the biggest percentage (25.8%) for -lactamase-producing S. aureus with resistance of eight antibiotics, while resistance of two antibiotics was the predominant mode of -lactamase nonproducing S. aureus (35.71%) with no resistance against more than four antibiotics. The study found that vancomycin, cefotaxime, and gentamicin were the most effective antibiotics against -lactamase-producing S. aureus strains isolated from both clinical and inanimate samples of ICUs having percentages of resistance as follows: 42.22%, 44.44%, and 44.44 %, respectively, and the antibiotic tetracycline had the biggest percentage of resistance (82.22%) against S. aureus strains under study.Although vancomycin and cefotaxime were the most effective antibiotics for -lactamase non-producing S. aureus strains, they had the lowest percentages of resistance in comparison to the first above group that recorded 13.33% and 20.0% of resistance, respectively, and tetracycline still being the weakest antibiotic having great resistance of 53.82% of isolates.The plasmid profiles in -lactamase-producing and non-producing MDRSA were also determined in this study. When the band molecular weight ranged between 300 and 600 base pairs (bp), a clear main band appeared in the range 550-570 bp for -lactamase-producing S. aureus. When the band molecular weight ranged between 200 and 700 bp, a clear main band appeared each in the band range 450-470 bp and 690-700 bp for -lactamase-producing S. aureus.