Abstract and Introduction
Abstract
Infections with Pseudomonas aeruginosa are a major health problem, especially for immune-compromised and cystic fibrosis patients, owing to the particular drug resistance of the microorganism. The aim of this review is to provide recent insights into strategies under investigation for prevention and therapy of these infections. In this survey, the approach directed against bacterial biofilm formation and quorum-sensing systems was focused, along with the evaluation of the treatment with bacteriophages. New interesting, developmental studies and clinical trials to prevent or treat infections due to this opportunistic pathogen are based on active and passive immunotherapy. Some monoclonal antibodies and different vaccines against this microorganism have been developed in the last few decades, even though to date none of them have obtained market authorization.
Introduction
Pseudomonas aeruginosa (PA) is a Gram-negative opportunistic microorganism that can be found in the environment. It is an important nosocomial pathogen, which causes different severe acute and chronic infections. Moreover, infections with PA are a major health problem for immune-compromised patients and individuals with cystic fibrosis (CF).[1,2] In fact, given the ubiquitous presence of this microorganism, it is understandable that the healthy immune system is quite capable of controlling infections. However, susceptible individuals, particularly those affected by HIV infection, recipients of transplanted organs, cytotoxic drug addicts or burn patients with vascular damage hindering localized phagocytosis, frequently suffer from infections caused by this pathogen.[3,4] Impaired respiratory clearance mechanisms are present in patients with bronchiectasis, a condition that predisposes to colonization and infection by PA. Chronic infections of the respiratory tract are a major cause of the increased morbidity and mortality of individuals with CF.[5–7] The prevalence of PA infection varies widely among CF centers.[8] According to our previous results obtained by assessing microorganisms isolated from the expectorations of CF adult patients attending a CF referral center over a period of 5 years,[9] the mean prevalence of PA infection during the period of the study was 44%, similar to percentages found in Naples (Italy) by Lambiase et al.[10] and in Germany by Valenza et al..[11]
PA, which can survive in different physical conditions, can be responsible for infections determined by medical devices and related to hospital environments. This microorganism is particularly resistant to the current antibiotic arsenal; in fact, it displays intrinsic multidrug resistance (MDR) and has a tremendous capacity to acquire further resistance mechanisms.[12,13] Recently, widespread extensively drug-resistant PA clones have been reported.[14] Moreover, during chronic infections, the organism can sometimes adopt a mucoid phenotype and is also thought to adopt a biofilm-like mode of growth, resulting in protection from host immune and antibiotic attack, with an oxygen limitation and low bacterial metabolic activity.[15]
Future Microbiol. 2014;9(7):917-928. © 2014 Future Medicine Ltd.
