Asmaa A Hashem1, Noha M Abd El Fadeal2, Atef S Shehata3,1. 1. Department of Microbiology and Immunology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt. 2. Department of Medical Biochemistry, Faculty of Medicine, Suez Canal University, Ismailia, Egypt. 3. Department of Microbiology and Immunology, Faculty of Medicine, Jazan University, Jazan, Kingdom of Saudi Arabia.
Abstract
PURPOSE: Catheter-related bloodstream infections (CRBSIs) are among the most common hospital-acquired infections. We aimed to survey methicillin resistance, biofilm production and susceptibility to vancomycin, linezolid and other antibiotics for staphylococci isolated from CRBSIs. METHODOLOGY: Fifty-eight isolates [20 S. aureus and 38 coagulase-negative staphylococci (CoNS; 20 Staphylococcusepidermidis, nine Staphylococcushaemolyticus, three Staphylococcusschleiferi, two Staphylococcuswarneri and four Staphylococcuslugdunensis)] were tested for methicillin resistance by cefoxitin disk diffusion and detection of the mecA gene by PCR; biofilm-forming ability using Congo red agar and tissue culture plate methods; susceptibility to ciprofloxacin, clindamycin, cotrimoxazole, erythromycin, gentamicin, linezolid, rifampicin and tetracycline; and MIC determination for vancomycin.Results/Key findings. Cefoxitin resistance was detected among 40 % (8/20) S. aureus isolates, 70 % (14/20) S. epidermidis isolates and 16.7 % (3/18) of other CoNS, although the mecA gene was detected in 45 % (9/20) S. aureus isolates, 35 % (7/20) S. epidermidis isolates and 16.7 % (3/18) of other CoNS. Biofilm-forming ability ranged from 45 to 75 %. Methicillin-resistant S. aureus and other CoNS were considered to be more virulent than methicillin-resistant S. epidermidis due to the higher biofilm forming abilities of the former. All tested isolates exhibited 100 % sensitivity to vancomycin and linezolid, irrespective of their methicillin resistance or biofilm-forming ability. Rifampicin showed overall sensitivity of 75.9 %. Varying degrees of multi-resistance were found for the other antibiotics. CONCLUSION: Vancomycin, linezolid and rifampicin could be used effectively against methicillin-resistant staphylococci isolated from CRBSIs.
PURPOSE: Catheter-related bloodstream infections (CRBSIs) are among the most common hospital-acquired infections. We aimed to survey methicillin resistance, biofilm production and susceptibility to vancomycin, linezolid and other antibiotics for staphylococci isolated from CRBSIs. METHODOLOGY: Fifty-eight isolates [20 S. aureus and 38 coagulase-negative staphylococci (CoNS; 20 Staphylococcusepidermidis, nine Staphylococcushaemolyticus, three Staphylococcusschleiferi, two Staphylococcuswarneri and four Staphylococcuslugdunensis)] were tested for methicillin resistance by cefoxitin disk diffusion and detection of the mecA gene by PCR; biofilm-forming ability using Congo red agar and tissue culture plate methods; susceptibility to ciprofloxacin, clindamycin, cotrimoxazole, erythromycin, gentamicin, linezolid, rifampicin and tetracycline; and MIC determination for vancomycin.Results/Key findings. Cefoxitin resistance was detected among 40 % (8/20) S. aureus isolates, 70 % (14/20) S. epidermidis isolates and 16.7 % (3/18) of other CoNS, although the mecA gene was detected in 45 % (9/20) S. aureus isolates, 35 % (7/20) S. epidermidis isolates and 16.7 % (3/18) of other CoNS. Biofilm-forming ability ranged from 45 to 75 %. Methicillin-resistant S. aureus and other CoNS were considered to be more virulent than methicillin-resistant S. epidermidis due to the higher biofilm forming abilities of the former. All tested isolates exhibited 100 % sensitivity to vancomycin and linezolid, irrespective of their methicillin resistance or biofilm-forming ability. Rifampicin showed overall sensitivity of 75.9 %. Varying degrees of multi-resistance were found for the other antibiotics. CONCLUSION:Vancomycin, linezolid and rifampicin could be used effectively against methicillin-resistant staphylococci isolated from CRBSIs.