Multidrug-resistantPseudomonas aeruginosaandAcinetobacter baumannii: resistance mechanisms and implications for therapy

Abstract

Pseudomonas aeruginosa and Acinetobacter baumannii are major nosocomial pathogens worldwide. Both are intrinsically resistant to many drugs and are able to become resistant to virtually any antimicrobial agent. An increasing prevalence of infections caused by multidrug-resistant (MDR) isolates has been reported in many countries. The resistance mechanisms of P. aeruginosa and A. baumannii include the production of beta-lactamases, efflux pumps, and target-site or outer membrane modifications. Resistance to multiple drugs is usually the result of the combination of different mechanisms in a single isolate or the action of a single potent resistance mechanism. There are many challenges in the treatment of MDR P. aeruginosa and A. baumannii, especially considering the absence of new antimicrobials in the drug-development pipeline. In this review, we present the major resistance mechanisms of P. aeruginosa and A. baumannii, and discuss how they can affect antimicrobial therapy, considering recent clinical, microbiological, pharmacokinetic and pharmacodynamic findings of the main drugs used to treat MDR isolates.

Outbreaks, persistence, and high mortality rates of multiresistant Pseudomonas aeruginosa infections in a hospital with AIDS-predominant admissions

“…31 We did not completely assess the resistance mechanism in our tested strains, but all of the isolates were negative for MBL production. Unfortunately, we did not have the necessary resources to study other antibiotic-resistance mechanisms previously described in MR-PA. 8,32 MDR-PA infections probably acquired new or derepressed resistance mechanisms during the study period. Sequential emergence of resistance is likely due to the administration of different antibiotics at different time periods following the development of resistance.…”

“…[1][2][3][4][5][6][7][8] These infections are usually associated with high mortality rates. [1][2][3][4][5][6] Also, in patients with human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS), authors have described persistent and recurrent infections caused by non-MR-PA strains.…”

Molecular Identification of Pathogenic Enterococci and Evaluation of Multi-drug Resistance in Enterococcus Species Isolated From Clinical samples of Some Hospitals in Tehran, Iran

“…Glycopeptides such as vancomycin and teicoplanin are the selective and usually the last-resort choice for the hospital-acquired multidrug-resistant (MDR) Gram-positive infections (5). Inappropriate administration and indiscriminate use of broadspectrum beta-lactams, aminoglycosides, and carbapenems as well as long-term hospitalization influence the spread of MDR bacteria (6).…”

Alternativas terapêuticas para o tratamento de infecções por Pseudomonas aeruginosa multirresistentes endêmicas no Brasil.

“…Dentre os diversos mecanismos de resistência ressaltam-se: inativação ou degradação enzimática dos antimicrobianos por enzimas, super expressão de bombas de efluxo, perda de porina, alterações no sítio alvo (Kanj, Kanafani, 2011;Muller et al, 2011;Zavascki et al, 2010).…”

“…Dentre os múltiplos mecanismos de resistência ressaltam-se: enzimas modificadoras de aminoglicosídeos, super expressão de bombas de efluxo, perda de porina, alterações no sítio alvo (Kanj, Kanafani, 2011;Muller et al, 2011;Poole, 2011;Strateva, Yordanov, 2009;Zavascki et al, 2010).…”