Low-level resistance and clonal diversity of Pseudomonas aeruginosa among chronically colonized cystic fibrosis patients.

A prospective study was conducted in Brazil to evaluate antimicrobial resistance patterns and molecular epidemiology of Pseudomonas aeruginosa isolates from cystic fibrosis (CF) patients with chronic lung infection. All isolates were obtained between May 2009 and June 2010 from 75 patients seen in four reference centers in Brazil: HCPA (20 patients) and HEOM (15 patients), located in southern and northeastern Brazil, respectively; IFF (20 patients) and HUPE (20 patients), both in southwestern Brazil. Antimicrobial susceptibility testing, PCR for detection of carpapenemases, and pulsed-field gel electrophoresis (PFGE) were performed in 274 isolates. A total of 224 PFGE types were identified and no clones were found circulating among the centers or within the same center. Despite the chronic infection, most patients were colonized by intermittent clones. Only three patients (4%) maintained the same clone during the study. The resistance rates were lower than 30% for the majority of antimicrobials tested in all centers and only 17% of isolates were multiresistant. Isolates (n = 54) with reduced susceptibility to imipenem and/or meropenem presented negative results for blaSPM-1, blaIMP-1, blaVIM , and blaKPC genes. Our results indicate an unexpected low level of antimicrobial resistance and a high genotypic diversity among P. aeruginosa from Brazilian chronic CF patients.

Prevalence and antimicrobial susceptibility of respiratory pathogens in patients with cystic fibrosis.

Respiratory infection is very common in patients suffering from cystic fibrosis (CF). However, the antimicrobial resistance rate of isolates from CF patients is not often documented. In this study, 279 respiratory specimens of 146 patients were prospectively collected from July to December 2006. Microbiological cultures and antimicrobial susceptibility tests of the most frequently isolated bacteria were performed. Sputum and oropharyngeal swabs were processed for culture. During the study period, 50% of the patients harbored Staphylococcus aureus, 35% Pseudomonas aeruginosa, 4.7% Haemophilus influenzae. Methicillin resistant S. aureus (MRSA) were detected in 8 (6%) patients; ESBL and MBL-producing P. aeruginosa were not identified in these patients. The detection of MRSA in CF patients confirms that antimicrobial resistance patterns should be always kept under surveillance. Moreover, hygiene regulations in CF clinics should prevent a further spread of resistant bacterial strains.

Prevalence and antimicrobial susceptibility of respiratory pathogens in patients with cystic fibrosis

Respiratory infection is very common in patients suffering from cystic fibrosis (CF). However, the antimicrobial resistance rate of isolates from CF patients is not often documented. In this study, 279 respiratory specimens of 146 patients were prospectively collected from July to December 2006. Microbiological cultures and antimicrobial susceptibility tests of the most frequently isolated bacteria were performed. Sputum and oropharyngeal swabs were processed for culture. During the study period, 50 percent of the patients harbored Staphylococcus aureus, 35 percent Pseudomonas aeruginosa, 4.7 percent Haemophilus influenzae. Methicillin resistant S. aureus (MRSA) were detected in 8 (6 percent) patients; ESBL and MBL-producing P. aeruginosa were not identified in these patients. The detection of MRSA in CF patients confirms that antimicrobial resistance patterns should be always kept under surveillance. Moreover, hygiene regulations in CF clinics should prevent a further spread of resistant bacterial strains.