One of the main causes of antibiotics drug resistance is antibiotic overuse and in some cases misuse due to incorrect diagnosis. Bacterial antibiotic resistance is a significant issue faced by various industries including the food and agricultural industries the medical and veterinary profession and others. The potential for transfer of antibiotics resistance or of potentially lethal antibiotic resistant bacteria for example from a food animal to human consumer is of particular concern. A method of controlling development and spread of antibiotic-resistant bacteria include changes in antibiotic usage and pattern of usage of different antibiotics. However the ability of bacteria to adapt to antibiotic usage overcomes such conventional measures and requires the continued development of alternative means of control of antibiotic resistance bacteria.
This report explains one method evaluated for control that is reducing or removing antibiotic resistance so called “curing” of antibiotic resistance. Antibiotic resistance is formed in the chromosomal elements. Thus the elimination of such drug-resistance plasmids results in loss of antibiotics resistance by the bacterial cell. “Curing” of a microorganism refers to the ability of the organism to spontaneously lose a resistance plasmid under the effect of particular compounds and environmental conditions thus recovering the antibiotic sensitive state. Plasmid is one of the several environmental and genetic factors that carry the resistance property against a specific drug or a number of drugs in bacteria (ref). R-plasmids from resistant strains of an organism may transfer to a sensitive counterpart that would in due course show the same drug resistance as the donor strain (ref).
Plasmid can also be eliminated by curing agents which can be used to display the role of R-plasmid in drug resistance. The technique used to promote the curing include exposing the host strain to elevated temperatures, use of chemical agents such as intercalating dyes (acridine orange, ethidium bromide), treatment with crystal violet, sodium dodecyl sulfate (SDS), thymidine starvation and exposure to UV radiation (ref). Different plasmids vary considerably in their property to be cured and not necessarily depending upon properties of specific plasmid. When working with some plasmid-cured derivative allowing a direct comparison to be made between the plasmid-containing and the plasmid-cured cells. Some plasmids undergo spontaneous segregation and deletion but the majority is extremely stable and requires the use of curing agents or other procedures to increase the frequency of spontaneous segregation and deletion but the majority is extremely stable and requires the use of curing agents of other procedures to increase the frequency of spontaneous segregation. The usefulness of curing agents is unpredictable in many bacterial strains as there are no standard protocols applicable to all plasmids (ref).
As no universally effective curing agent has yet been identified curing experiments are generally conducted on trial and error basis both with respect to the choice of the curing agent and the culturing conditions used. Some curing agents work in non specific way by damaging and stressing out the cells while some seem to act much selectively (ref). The present study is a preliminary effort to observe the curing efficiencies of lactic acid bacteria on multidrug resistant microorganisms.
The use of antiplasmid agents in combination with antibiotics may serve as a possible way to combat this resistance encoded by plasmids (Molnar et al., 2003). However, majority of the known plasmid curing agents including acridine orange, ethidium bromide and sodium dodecyl sulphate which are toxic or mutagenic and hence unsuitable for therapeutic applications. Also, no single curing agent can cure all plasmids from different hosts. Thus, there is a constant need to develop new curing agents with high efficacy and safety. Traditional natural products have always been a rich source of drug discovery programs (Newman et al.
, 2000). There is evidence for the health properties that are attributable to exopolysaccharides from Lactic Acid Bacteria (LAB). Keeping in view the potential of plasmid in multidrug resistance present work entitled plasmid profiling of multidrug resistant bacterial strains has been carried out with following objectives:Revival of multidrug resistant bacterial stains and Lactic acid bacterial strains obtained from department of Biotechnology, HP University Shimla (India).