A genetic study of a Staphylococus aureus plasmid involving cure and transference

Abstract

High frequency transfer and elimination of drug resistance may indicate an extrachromosomal inheritance of genetic determinants. This study shows the cure and transfer of a small plasmid and tetracycline resistance in Staphylococcus aureus 1030 (55)Tet R strains. Several methods are available for plasmid elimination. We used ethidium bromide, an agent that binds to DNA, and thus inhibits DNA polymerase. This caused a high frequency of loss of the small plasmid and resistance to tetracycline. Transfer of tetracycline resistance was done in a mixed culture at a frequency of 10-6 • This type of study is very important to physicians and epidemiology investigators and provides better knowledge on antibiotic-resistance mechanisms that may occur in vivo in a hospital environment.

A study on resistance loss of multidrug resistant (MDR) Pseudomonas aeruginosa strains after treatment with dilutions of acridine orange

“…Earlier studies reported no effect of acridine orange on plasmids of P. aeruginosa (Pattnakik et al, 1995;Al-Amir et al, 1999). Reports of some other earlier studies stated a reversion in the resistance of some multiple drug resistant strains following exposure to acridine orange (Naomi, 1978;Darini, 1996;Adeleke and Odetola, 1997).…”