Fatima Ahmed^1,, Ashraf Elhag², Omar Mahmod¹, Sababil S Ali¹, Mushal Allam³, A M ElHussein⁴

Treating staphylococcal infection has become a challenge to the physicians, as this bacterium formed one of the multidrug resistant superbugs. The rapid and wide spread of resistant strains demand in depth investigation of resistance patterns of this organism. This study aimed to investigate the resistance patterns of Staphylococcus aureus and determine the incidence of multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) strains in Sudan. The study was designed as cross-sectional study, conducted over a time span of 15 months collected from five different states in Sudan. A total of 335 Staphylococcus aureus isolates were collected from different sources. The isolates were identified by microbiological tests and PCR. Antimicrobial susceptibility testing was performed using the Standard Disc Diffusion method (Kirby-Bauer's) and the isolates categorized into MDR, XDR, or PDR according to their resistance patterns following the recommendation and definitions obtained by Clinical and Laboratory Standards Institute (CLSI), European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC) USA. The highest rates of resistance among the fifteen antimicrobial categories tested were for the ¦Â-lactam and ¦Â-lactam/¦Â-lactamase inhibitors category, in which 307 (91.6%) isolates were resistant to penicillin, 299(89.3%) to oxacillin, 235(70%) to ceftazidime, 193 (57.6%) and 169 (50.4%) to Amoxicillin/Clavulanic and Amoxicillin/Sulbactam respectively. Followed by the Macrolides category, in which 154(46%) were Erythromycin resistant. Resistance to Fluoroquinolones category was the third highest rate with 89(26%). Resistance to Tetracyclines, Aminoglycosides, Carbapenems, Trimethoprim/Sulphamethoxazole, Clindamycin, Rifampicin, Chloramphenicol and Phosphonic acid ranged from 26% to 13.1%. The lowest resistance was for Oxazolidinones (Linezolid), Anti-MRSA Cephalosporins (Ceftaroline) and Glycopeptide (Teicoplanin) with percentages of 2.4%, 0.9% and 0.6% respectively. Based on the results of antimicrobial susceptibility, 20(6%) of the isolates categorized as non- Multidrug resistant (non-MDR), 310(93.7%) as multidrug resistant (MDR), 2(0.6%) was extensively drug resistant (XDR) and no pan-drug resistant (PDR) was found. The MDR strains are expanded in all Sudan and with resistance patterns near to XDR, which make the evolution into XDR and even PDR possible in the near future. This is one of the challenging matters demanding immediate action.

antimicrobial categorization, multidrug resistance, extensively drug resistance, pan-drug resistance