Extensively drug-resistant Pseudomonas aeruginosa: risk of bloodstream infection in hospitalized patients

Abstract

Several studies have suggested that resistance determinants usually reduce virulence. However, their contribution to decrease bloodstream infections is unclear. Our aim was to identify risk factors of extensively drug-resistant (XDR) Pseudomonas aeruginosa (PA) bacteremia and to assess the prevalence of XDR-PA bacteremia. A retrospective study of PA bloodstream infections in our patient population with at least one clinical sample isolate due to PA (2006-2007) was carried out. A total of 2,131 patients with PA clinical samples were detected. Among 1,657 patients with susceptible-PA isolates, 95 developed PA-susceptible bacteremia. Concomitantly, among 474 patients with multidrug-resistant (MDR)-PA isolates, 265 with XDR-PA, and 209 with non-XDR MDR-PA, 43 developed XDR-PA bacteremia and 13 non-XDR MDR-PA bacteremia, respectively. Pulsed-field gel electrophoresis (PFGE) revealed the clonal nature of the two predominant XDR-PA phenotypes and genetic heterogeneity in non-XDR MDR-PA phenotypes. The proportion of XDR-PA bacteremia was higher than the proportion of bacteremia in the susceptible-PA population (16 % vs. 6 %; p < 0.001). A logistic regression model identified prior exposure to fluoroquinolones [odds ratio (OR) 2.80; 95 % confidence interval (CI) 1.02 to 7.70] as the independent variable associated with XDR-PA bacteremia. Our study suggests that XDR-PA strains have a greater ability to develop bacteremia. It remains unclear as to whether this invasive capacity depends on clonal traits or on other virulence determinants.

Multidrug and Extensive Drug Resistance inPseudomonas aeruginosaClinical Isolates from a Portuguese Central Hospital: 10-Year Survey

“…In present work, XDR rates (7.4%) were inferior to those reported in the literature. 4,12,20 However, since we did not test the susceptibility to phosphonic acids or polymyxins 18 in all isolates, XDR rates in the studied hospital can be higher than that here stated. Regarding PDR, as all XDR isolates were COL susceptible, we may assuredly affirm that no PDR isolates were observed in the studied hospital in the last 10 years.…”

“…In a review made by Falagas and Bliziotis, 12 1.3% and 0.08% of all P. aeruginosa (n = 8,705, between 2001 and 2004) were considered XDR or PDR, respectively, but these authors did not use the currently approved nomenclature. 18 Peña et al 20 reported a 55.9% incidence of XDR in 474 MDR P. aeruginosa strains and Cabot et al 4 reported 10.5% of XDR strains (n = 190), both from Spanish hospitals. In present work, XDR rates (7.4%) were inferior to those reported in the literature.…”

An outbreak of extremely drug-resistant Pseudomonas aeruginosain a tertiary care pediatric hospital in Italy

“…The observed mortality rate was higher than that reported for MDR-PA bacteremia cases in children [1], but lower than that described in a nosocomial outbreak of pan-antibiotic-resistant P. aeruginosa [14]. A recent Spanish study suggested that XDR-PA strains are particularly prone to cause bacteremia, though it was unclear whether this invasive capacity depended on clonal traits or on other virulence determinants [24]. As expected, we observed that severe neutropenia was significantly associated with XDR-PA bacteremia, compared to other infections or colonization due to XDR-PA.…”

The prophylactic effects of human IgG derived from sera containing high anti-PcrV titers against pneumonia-causingPseudomonas aeruginosa

“…1,2 Pseudomonas aeruginosa is a major opportunistic pathogen capable of causing acute and fatal infections, such as ventilator-associated pneumonia, bacteremia, and sepsis in critically ill individuals. [3][4][5] P. aeruginosa clinical isolates are often resistant to most b-lactams and fluoroquinolones and, sometimes, resistant to aminoglycosides, such as gentamicin and amikacin, thus categorizing them as multi-drug resistant P. aeruginosa (MDRP). 4,[6][7][8][9] Limitations in the number of effective antimicrobial agents for treating MDRP infections leads to the high mortality rates associated with the acute lung injury induced by this bacterium.…”

“…[3][4][5] P. aeruginosa clinical isolates are often resistant to most b-lactams and fluoroquinolones and, sometimes, resistant to aminoglycosides, such as gentamicin and amikacin, thus categorizing them as multi-drug resistant P. aeruginosa (MDRP). 4,[6][7][8][9] Limitations in the number of effective antimicrobial agents for treating MDRP infections leads to the high mortality rates associated with the acute lung injury induced by this bacterium. 5 While seeking new prophylactic or therapeutic strategies that do not rely on conventional antimicrobial agents, we have investigated the use of an immunotherapy approach that targets the P. aeruginosa type III secretion system.…”