Physiological and molecular characteristics of carbapenem resistance in Klebsiella pneumoniae and Enterobacter aerogenes

• Published in: Journal of infection in developing countries 2016-06, Vol.10 (6), p.592-599
• Main Authors: Pereira, Rito Santo, Dias, Vanessa Cordeiro, Ferreira-Machado, Alessandra Barbosa, Resende, Juliana Alves, Bastos, André Netto, Andrade Bastos, Lucas Quinet, Andrade Bastos, Victor Quinet, Bastos, Ricardo Villela, Da Silva, Vânia Lúcia, Diniz, Cláudio Galuppo
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents - pharmacology; Antibiotics; beta-Lactam Resistance; Biofilms - growth & development; Brazil; Carbapenems - pharmacology; CRE bacteria; Cross-Sectional Studies; Disinfectants - pharmacology; Enterobacter aerogenes - drug effects; Enterobacter aerogenes - genetics; Enterobacter aerogenes - physiology; Enterobacteriaceae Infections - microbiology; Female; Humans; Klebsiella pneumoniae - drug effects; Klebsiella pneumoniae - genetics; Klebsiella pneumoniae - physiology; Male; Middle Aged; Oxidative Stress; Physiology; Polymerase Chain Reaction; Stress, Physiological; Tertiary Care Centers; Young Adult
• ISSN: 1972-2680; 2036-6590; 1972-2680
• DOI: 10.3855/jidc.6821

Bacterial resistance is a growing concern in the nosocomial environment in which Klebsiella pneumoniae and Enterobacter aerogenes play an important role due to their opportunism and carbapenemase-production. This work aimed to evaluate physiological and molecular characteristics of carbapenem-resistant K. pneumoniae and E. aerogenes isolated in a Brazilian tertiary hospital. In total, 42 carbapenem-resistant bacteria isolated from clinical specimens were included (21 K. pneumoniae and 21 E. aerogenes). Drug-sensitive K. pneumoniae (n = 27) were also included. Antimicrobial susceptibility and biocide tolerance patterns, hemolytic activity, tolerance to oxidative stress, and aggregative ability were assessed. Genetic markers related to carbapenem resistance, or ESBL-production were screened by PCR. Compared to drug-sensitive strains, carbapenem-resistant K. pneumoniae were more tolerant to biocides and to oxidative stress, and they displayed an increase in biofilm formation. The genetic markers blaKPC (95.2%) and blaTEM (90.5%) were the most frequent. Among the carbapenem-resistant E. aerogenes strains, blaKPC, and blaTEM were detected in all bacteria. Drug-sensitive E. aerogenes were not isolated in the same period. blaSHV, blaVIM, and blaCTX markers were also observed among carbapenem-resistant bacteria. Results suggest that carbapenemase-producing enterobacteria might show peculiar characteristics regarding their physiology associated with their environmental persistency, virulence, and multidrug resistance. The observed phenomenon may have implications not only for antimicrobial chemotherapy, but also for the prognosis of infectious diseases and infection control.