Abstract

MATRICES OF DEGREE OF ASSOCIATION OF PAIRED ANTIBIOTIC RESISTANCE OF STAPHYLOCOCCUS AUREUS HARVESTED FROM CANCER AND NONCANCER PATIENTS

*Mohemid Maddallah Al-Jebouri, Ibraheem Abdul-kareem Al-Ani

Abstract

Background: Resistance transfer studies and plasmid screening experiments demonstrated that multi-resistance phenotype was due to transmissible plasmid and/or transposons. These strains also shown resistance to cephalosporins which is chromosome encoded. Most of hospital infections caused by multiple resistant organisms, especially multiple resistant Staphylococcus aureus which has been frequently isolated from patients. Materials and Methods: 400 patients were included and they were 200 patients with cancer diseases and 200 patients complaining of other illnesses. Swabs were taken from nares, sores and wounds and S. aureus was isolated and identified. Antibiotic sensitivity was carried out and paired resistance of antibiotics was recorded. Results: The most problematic antibiotics were penicillin G and ampicillin, showing resistance rates above 80– 90%. The resistance to pairs of antibiotics like ampicillin and penicillin, penicillin and tetracycline, ampicillin and tetracycline, ampicillin and erythromycin, and penicillin and erythromycin were 146, 84, 82, 49 and 47 respectively. It was noticed that 11.8% of the isolates tested which were resistant to erythromycin being resistant to sulfonamides whereas 66.6% of isolates that resistant to sulfonamides were resistant to erythromycin. It was also concluded that 64.5% of isolates resistant to streptomycin were resistant to tetracycline, and at the same time 22.9% tetracycline-resistant isolates were resistant to streptomycin. The McNemar Chi-square association matrix demonstrated extensive and highly interconnected multidrug resistance among S.aureus isolates recovered from cancer and noncancer patients. Conclusions: The most problematic antibiotics were penicillin G and ampicillin, showing resistance rates above 80–90%. The high multidrug resistance rate indicated strong antibiotic selective pressure and possible hospital-associated resistance circulation. Overall, cancer and noncancer isolates showed broadly similar resistance profiles, with only minor differences for selected antibiotics. The resistance to pairs of antibiotics like ampicillin and penicillin, penicillin and tetracycline, ampicillin and tetracycline, ampicillin and erythromycin, and penicillin and erythromycin were 146, 84, 82, 49 and 47 respectively. The paired antibiotic resistance analysis demonstrated extensive multidrug resistance among S. aureus isolates recovered from cancer and noncancer patients. The analysis showed that the strongest resistance associations occurred predominantly among β-lactam antibiotics, particularly between penicillin G and ampicillin, which exhibited extremely high paired resistance frequencies exceeding 90%. The association analysis revealed strong statistical relationships between several antibiotic pairs, indicating that resistance to one antibiotic was frequently accompanied by simultaneous resistance to another antibiotic within the same isolates.

Keywords: Patients, cancer, S. aureus. Antibiotics resistance, matrices.