Phenotypic and Molecular Characterization of Resistance Mechanisms in Pseudomonas Aeruginosa Isolated from Blood Stream and Respiratory Tract Infections

Abstract

P. aeruginosa is an aerobic non fermenting Gram-negative bacilli, with the remarkable ability to thrive under a wide range of environmental conditions. P. aeruginosa is a therapeutic challenge for the treatment of healthcareassociated infections. The choice of suitable anti-pseudomonal agents for treatment is significant in optimizing clinical effects. Extensive use of antimicrobial agents and the evolution of AMR strategies of this bacteria have resulted in the emergence of nosocomial bacterial pathogens with AMR. These Superbugs have severely threatened therapeutic choices in the last few decades. This study provides insights into the molecular resistance mechanisms by which these bugs resist a wide range of antimicrobials and hence the therapy can be tailored. Multidrug resistance phenotypes in these clinical isolates were caused by the interaction of several different resistance mechanisms occurring within the same strain such as overexpression of efflux, AmpC overproduction or decreased expression of outer membrane porin (OprD). These strains highlight the ability of P. aeruginosa to develop dual resistance to different classes of antimicrobial agents through independent mechanisms of resistance and emphasize the need for the judicious use of available therapy when dealing with P.aeruginosa in order to prevent multidrug resistance. Overall, this research has shown the importance of studying antimicrobial resistance in a clinically important pathogen, P.aeruginosa. Observations of international high-risk clones are important in the spread of MBL-producing P. aeruginosa in the hospital setting. The success of these clones is likely to be due to multiple factors, which may include the association with particular genomic islands or the absence of host defense mechanisms against exogenous DNA elements. Future work should focus on further elucidating the reasons for the success of these clones, to better understand how to limit the spread of these multi-drug resistant organisms.