RESUMEN
Nonfermenting gram-negative (NFGN) bacteria were isolated from cystic fibrosis (CF) patients and subjected to susceptibility testing and whole-genome sequencing. Among 170 enrolled CF patients, 112 (65.9%) were colonized with at least 1 key NFGN species. The species-specific infection rate was highest for Pseudomonas aeruginosa (40.6%) followed by Stenotrophomonas maltophilia (14.1%), Achromobacter spp. (9.4%), and Burkholderia cepacia complex (Bcc, 8.2%) demonstrating a significant age-dependent increase for P. aeruginosa and Achromobacter spp., but not for S. maltophilia or Bcc. P. aeruginosa sequence types (STs) related to high-risk epidemic and global CF clones were carried by 12 (7.1%) and 13 (7.6%) patients, respectively. In total, 47% NFGN isolates, predominantly P. aeruginosa, harbored at least 1 plasmid-borne resistance gene; 5 ST235 isolates carried blaVIM2. Pathogenicity island-borne virulence genes were harbored by 9% NFGN isolates. These findings in conjunction with frequent early colonization by Bcc raised serious concerns regarding infection control in Russian CF centers.
Asunto(s)
Fibrosis Quística , Stenotrophomonas maltophilia , Humanos , Antibacterianos/farmacología , Fibrosis Quística/complicaciones , Fibrosis Quística/microbiología , Farmacorresistencia Bacteriana , Bacterias Gramnegativas , Stenotrophomonas maltophilia/genética , Pseudomonas aeruginosa/genéticaRESUMEN
Pseudomonas aeruginosa is a serious opportunistic pathogen demonstrating a high level of resistance to many groups of antibiotics, including carbapenems. This study aimed to characterise the molecular epidemiology and prevalence of mobile genetic elements associated with resistance to carbapenems among P. aeruginosa (CRPA) clinical isolates. Among 145 carbapenem-resistant P. aeruginosa isolates, 34 different sequence types (STs) were detected; the six most common STs were ST654 (24%), ST235 (24%), ST111 (8%), ST446 (6%), ST357 (5%) and ST2592 (a novel single-locus variant of ST357) (4%). A carbapenemase gene was found in 94 isolates (64.8%). The blaVIM-2 gene was harboured by 64 isolates (44.1%) restricted to ST111, ST235 and ST654, and the blaGES-type and blaOXA-10 group genes were each detected in 15 isolates (10.3%); none of other tested carbapenemase genes, including blaIMP, blaNDM and blaGIM, were detected. Among the blaVIM-2-positive isolates, five types of blaVIM-2-containing integrons were discovered, including In56, In559, In59-like, In59 and In249. The oprD gene was disrupted by an insertion sequence (IS) in 15.9% of isolates. Overall, five types of IS elements were found (ISPsme1, ISPa1328, ISPa26, ISPst2 and ISPa195). Observed rearrangements within variable regions of blaVIM-2-carrying integrons in conjunction with the discovery of a novel type of oprD-disrupting IS element illustrate the ongoing evolution of CRPA a, which warrants further investigation.
Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/genética , Carbapenémicos/farmacología , Integrones/genética , Porinas/genética , Pseudomonas aeruginosa/efectos de los fármacos , beta-Lactamasas/genética , Farmacorresistencia Bacteriana Múltiple/genética , Variación Genética/genética , Humanos , Pruebas de Sensibilidad Microbiana , Infecciones por Pseudomonas/tratamiento farmacológico , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/aislamiento & purificación , Federación de RusiaRESUMEN
Carbapenem-nonsusceptible (Carba-NS) Acinetobacter baumannii has emerged as an important cause of nosocomial infections. In the present study, we characterized 91 Carba-NS A. baumannii isolates collected from patients of surgical departments and intensive care units at three hospitals in Moscow in 2012-2015. Multilocus sequence typing (MLST) using the Oxford (Oxf) scheme identified 16 sequence types (STs) of three clonal complexes (CCs), including CC92Oxf (67%), CC109Oxf (1%), CC944Oxf (29%), and the singleton ST1100Oxf (3%). CC944Oxf was composed of ST944Oxf (n = 16) and two of its newly described single locus variants ST1103Oxf (n = 3) and ST1104Oxf (n = 7); all the three STs were identical to the Pasteur (Pas) MLST scheme ST78. All CC944Oxf/ST78Pas isolates were blaOXA-40-like positive and all but one isolate harbored a blaCTX-M-like gene. ST944Oxf was the only ST found in each of the three study hospitals. Biofilm growth capacity was similar among Carba-NS and nonclonal carbapenem-susceptible isolates. Our data demonstrate the predominance of two clonal lineages among Carba-NS A. baumannii. One of these, the uncommon blaOXA-40-like/blaCTX-M-like-positive clone of CC944Oxf/ST78Pas, seems to be endemic in Russia.