Disseminação de microrganismos multirresistentes: uma ameça global e um problema de saúde crítico

Multidrug-resistant organisms are usually associated with greater number of clinical manifestations and severe infections than those caused by susceptible pathogens. The high prevalence of antimicrobial resistance is a global concern, mainly in Latin America, where resistance levels are higher for important pathogens such as Gram-negative non-fermentative bacteria and Enterobacteriacae family, compared with those seen in US hospitals and Europe. The use of antimicrobial agents for the treatment of these infections is advantageous for the multidrug-resistant pathogens and contributes to the maintenance of the genetic determinants of resistance. Countries like Brazil, characterized by the allocation of limited financial resources for the health department, have in the infection prevention and control practices an economical necessity, because of the increased costs that nosocomial infection demand in addition to the reduction of rates morbidity and mortality

Clinical and Molecular Epidemiology of Multidrug-Resistant P. aeruginosa Carrying aac(6')-Ib-cr, qnrS1 and blaSPM Genes in Brazil.

We described a comprehensive analysis of the molecular epidemiology of multidrug-resistant (MDR) P. aeruginosa. Molecular analysis included typing by Pulsed Field Gel Electrophoresis, identification of genes of interest through PCR-based assays and sequencing of target genes. Case-control study was conducted to better understand the prognostic of patients and the impact of inappropriate therapy in patients with bacteremia, as well as the risk factors of MDR infections. We observed a high rate of MDR isolates (40.7%), and 51.0% of them was independently associated with inappropriate antibiotic therapy. Bacteremia was detected in 66.9% of patients, and prolonged hospital stay was expressive in those resistant to fluoroquinolone. Plasmid-mediated quinolone resistance genes (PMQR), qnrS1 and aac(6')Ib-cr, were detected in two different nosocomial isolates (5.3%), and the aac(6')-Ib7 variant was detected at a high frequency (87.5%) in those negative to PMQR. The presence of mutations in gyrA and parC genes was observed in 100% and 85% of selected isolates, respectively. Isolates harboring PMQR genes or mutations in gyrA and parC were not closely related, except in those containing SPM (São Paulo metallo-β-lactamase) clone. In addition, there is no study published in Brazil to date reporting the presence of Pseudomonas aeruginosa isolates harboring both qnrS1 and aac(6')Ib-cr genes, with alarming frequency of patients with inappropriate therapy

Antimicrobial therapy and clinical outcome of patients with bacteremia caused by <i>P</i>. <i>aeruginosa</i> resistant to carbapenems, fluoroquinolones and multiresistant.

<p>Antimicrobial therapy and clinical outcome of patients with bacteremia caused by <i>P</i>. <i>aeruginosa</i> resistant to carbapenems, fluoroquinolones and multiresistant.</p

Survival curve using the Kaplan–Meier method for patients who received appropriate antimicrobial therapy compared with those who received inappropriate therapy.

<p><i>P</i> ≤ 0.05 –statistically significant.</p

Characterization of <i>P</i>. <i>aeruginosa</i> isolates resistant to fluoroquinolones and/or carbapenems with regard to the minimum inhibitory concentration, <i>bla</i>_SPM, <i>bla</i>_VIM, <i>qnrS</i>, <i>aac(6´)-Ib-cr</i> and <i>aac(6´)-Ib</i>_<i>7</i> genes, quinolone resistance determining region mutations and the PFGE patterns.

<p>Characterization of <i>P</i>. <i>aeruginosa</i> isolates resistant to fluoroquinolones and/or carbapenems with regard to the minimum inhibitory concentration, <i>bla</i>_SPM, <i>bla</i>_VIM, <i>qnrS</i>, <i>aac(6´)-Ib-cr</i> and <i>aac(6´)-Ib</i>_<i>7</i> genes, quinolone resistance determining region mutations and the PFGE patterns.</p

<i>Pseudomonas aeruginosa</i> antimicrobial resistance and sensitivity profiles to the main antimicrobials of isolates from 242 episodes of hospital infections.

<p><i>Pseudomonas aeruginosa</i> antimicrobial resistance and sensitivity profiles to the main antimicrobials of isolates from 242 episodes of hospital infections.</p

UPGMA dendrogram of PFGE profiles of 21 clinical <i>P</i>. <i>aeruginosa</i> isolates used in this study using the Dice coefficient under 1% tolerance and 1% optimization.

<p>A similarity coefficient of 80% was chosen for cluster definition. ¹Plasmid-mediated quinolone resistance determinants or aminoglycoside 6′-N-acetyltransferase type Ib; ²Metallo-β-lactamase; ³negative; ⁴not tested.</p

Univariate and multivariate analyses, mortality and independent risk factors associated with multidrug-resistant <i>P</i>. <i>aeruginosa</i> infections.

<p>Univariate and multivariate analyses, mortality and independent risk factors associated with multidrug-resistant <i>P</i>. <i>aeruginosa</i> infections.</p

Clinical and Molecular Epidemiology of Multidrug-Resistant <i>P</i>. <i>aeruginosa</i> Carrying <i>aac(6')-Ib-cr</i>, <i>qnrS1</i> and <i>bla</i>_SPM Genes in Brazil

<div><p>We described a comprehensive analysis of the molecular epidemiology of multidrug-resistant (MDR) <i>P</i>. <i>aeruginosa</i>. Molecular analysis included typing by Pulsed Field Gel Electrophoresis, identification of genes of interest through PCR-based assays and sequencing of target genes. Case-control study was conducted to better understand the prognostic of patients and the impact of inappropriate therapy in patients with bacteremia, as well as the risk factors of MDR infections. We observed a high rate of MDR isolates (40.7%), and 51.0% of them was independently associated with inappropriate antibiotic therapy. Bacteremia was detected in 66.9% of patients, and prolonged hospital stay was expressive in those resistant to fluoroquinolone. Plasmid-mediated quinolone resistance genes (PMQR), <i>qnrS</i>_<i>1</i> and <i>aac(6’)Ib-cr</i>, were detected in two different nosocomial isolates (5.3%), and the <i>aac(6’)-Ib</i>_<i>7</i> variant was detected at a high frequency (87.5%) in those negative to PMQR. The presence of mutations in <i>gyrA</i> and <i>parC</i> genes was observed in 100% and 85% of selected isolates, respectively. Isolates harboring PMQR genes or mutations in <i>gyrA</i> and <i>parC</i> were not closely related, except in those containing SPM (São Paulo metallo-β-lactamase) clone. In addition, there is no study published in Brazil to date reporting the presence of <i>Pseudomonas aeruginosa</i> isolates harboring both <i>qnrS</i>_<i>1</i> and <i>aac(6’)Ib-cr</i> genes, with alarming frequency of patients with inappropriate therapy.</p></div