Sensitizing multi drug resistant Staphylococcus aureus isolated from surgical site infections to antimicrobials by efflux pump inhibitors|
Amr A, Baiomy; Ghada H, Shaker & Hisham A, Abbas
Background: Staphylococcus aureus is a common hospital acquired infections pathogen. Multidrug-resistant Methicillin-resistant
Staphylococcus aureus represents a major problem in Egyptian hospitals. The over-expression of efflux pumps is a main
cause of multidrug resistance. The discovery of efflux pump inhibitors may help fight multidrug resistance by sensitizing
bacteria to antibiotics. This study aimed to investigate the role of efflux pumps in multidrug resistance.
Methods: Twenty multidrug resistant S. aureus isolates were selected. Efflux pumps were screened by ethidium bromide
agar cartwheel method and polymerase chain reaction. The efflux pump inhibition by seven agents was tested by ethidium
bromide agar cartwheel method and the effect on sensitivity to selected antimicrobials was investigated by broth microdilution
Results: Seventy percent of isolates showed strong efflux activity, while 30% showed intermediate activity. The efflux genes
mdeA, norB, norC, norA and sepA were found to play the major role in efflux, while genes mepA, smr and qacA/B had a minor
role. Verapamil and metformin showed significant efflux inhibition and increased the sensitivity to tested antimicrobials,
while vildagliptin, atorvastatin, domperidone, mebeverine and nifuroxazide showed no effect.
Conclusion: Efflux pumps are involved in multidrug resistance in Staphylococcus aureus. Efflux pump inhibitors could increase
the sensitivity to antimicrobials.
Staphylococcus aureus; multidrug resistance; efflux pump inhibitors.