Epidemiology of bacterial infections in patients with cystic fibrosis involving Achromobacter and Burkholderia cepacia complex

Achromobacter sp. and Burkholderia sp. are troublesome pathogens in cystic fibrosis (CF) patients, mainly because they may have transmissible and multidrug resistant strains. The aim of this study was to analyze the Achromobacter and Burkholderia cepacia complex (Bcc) isolates from CF patients treated at the Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto (HCFMRP-USP) and Hospital das Clínicas da Faculdade de Ciências Médicas de Campinas (HCFCM-UNICAMP); to identify genus/species; to evaluate antimicrobial susceptibility; to investigate clonal relatedness among isolates by Pulsed-field Gel Electrophoresis (PFGE); to elucidate taxonomy and molecular epidemiology of the isolates by Multilocus Sequence Typing (MLST), and to relate the results to clinical data. Between July/2011 and September/2014, in both hospitals, the most prevalent species of Achromobacter and Bcc were A. xylosoxidans and B. vietnamiensis, respectively. The most effective antibiotics against Achromobacter sp. isolates of patients from HCFMRP-USP were imipenem and meropenem, and from HCFCM-UNICAMP were meropenem and ceftazidime. The most effective antibiotics against Bcc isolates of patients from HCFMRP-USP were sulfamethoxazole-trimethoprim and meropenem, and from HCFCM-UNICAMP were ceftazidime and meropenem. Cross-contamination was suspected among some patients who presented isolates with the same PFGE profile. In HCFMRP-USP, isolates of B. vietnamiensis from different patients showed the same PFGE profile, and only 2 patients had chronic infection. In HCFCM-UNICAMP, isolates of B. cenocepacia IIIB of 4 patients showed the same pulsetype, but none of the patients had chronic infection. Isolates of B. vietnamiensis and B. multivorans from different patients from HCFCM-UNICAMP also showed the same pulsetype, and only one patient colonized by B. multivorans had chronic infection. In HCFCM-UNICAMP, Achromobacter isolates showed unique profiles of PFGE, whereas in HCFMRP-USP cross-contamination was only suspected among patients colonized by A. xylosoxidans, and 3 of these patients had chronic infection. In both hospitals, 17 STs were identified in Bcc isolates, 14 of them for the first time and 3 STs (ST17, ST369 and ST911) presented intercontinental distribution. In both hospitals, some common STs (STs 1056, 1057, 369 and 911) were identified, which may suggest a common ancestor. In total, 6 different STs were identified in A. xylosoxidans isolates of patients from HCFMRP-USP, of which 3 STs were identified for the first time, and the other 3 STs presented intercontinental distribution. None of the species presented described epidemic strains. Patients chronically colonized by A. xylosoxidans showed less preserved Shwachman score, body mass index (BMI) and lung function, and slightly more frequent exacerbations than patients colonized by Bcc bacteria. This study provided the correct identification of the pathogens, allowing the adoption of more effective control measures and adequate treatments, besides updating the epidemiological database, which facilitates the multicentric collaborative analysis and assists in the control of global infection of these pathogens (AU)