|1746-2||Detection of phenotypic resistance and virulence in Aeromonas strains isolated from Antartica|
|Autores:||Rafael Arrabaça de Carvalho (FSP/USP - Faculdade de Saúde Pública USP) ; Bruna Aguiar (FSP/USP - Faculdade de Saúde Pública USP) ; Ana Paula Amaral (FSP/USP - Faculdade de Saúde Pública USP) ; Milena Dropa (FSP/USP - Faculdade de Saúde Pública USP) ; Livia Carminato Balsalobre (FSP/USP - Faculdade de Saúde Pública USP) ; Glavur Rogerio Matté (FSP/USP - Faculdade de Saúde Pública USP) ; Maria Helena Matté (FSP/USP - Faculdade de Saúde Pública USP) |
The genus Aeromonas is widely distributed in aquatic environments and recent studies include the genus Aeromonas in the emergent pathogens group because of its frequent association with local and systemic infections in healthy humans. In addition to the virulence factors present in some Aeromonas species, high rates of resistance to antibiotics have been detected in the genus. Aeromonas can adapt and not only survive but are also able to grow at low temperatures. Considering the importance of the genus Aeromonas and the absence of reports about its presence in Antarctic environment, we aimed to detect virulence factors and phenotypic resistance on the selected strains. Marine water samples were collected between 1997 and 2003, near the Brazilian Station Comandante Ferraz, near to the Antarctica Peninsula. The strains were maintained in freezer at -80o until 2012 when 17 strains previously identified as Aeromonas were re-isolated and antibiotic susceptibility tests were conduct using Imipenen (IPM), Ampicilin (AMP), Cefotaxime (CTX), Aztreonam (ATM), Cefotetan (CTT), Cephalotin (CFL), Cefepime (CPM), Ciprofloxacin (CIP), Tetracycline (TET), Gentamicin (GEN), Chloramphenicol (CL), Sulfamethoxazole trimethoprim (SXT). DNA extraction was carried out using heat-shock method, followed by PCR aiming to detect act, ast and alt enterotoxins, and flagella, lipase and elastase. The susceptibility tests showed all the strains were resistant to at least one of the tested antibiotics, 6% were resistant to TET, 11.8% to GEN, 17.6% were resistant to CPM and CIP, 35.3% to CTX and CTT, 47% to ATM, SXT and CEP, 53% to AMP and none the strains were resistant to IPM and CL. 23% of the strains were positive for alt, flagella and elastase, and 29.4% were positive for act and lipase. None of the strains were positive for ast. Antartica is an environment that is supposed to be free of human interference, especially in the years when the samples were collected. This information shows that Aeromonas carry those resistances intrinsically or the spread of resistance by mobile elements has reached this environment. The virulence factors found in the Antartica strains show that these characteristics are shared between Aeromonas isolated from several samples and environments, such as soil, food, clinical samples and sewage, confirming the virulence factors that these organisms may possess even in extreme environments.
Palavras-chave: Antartica, Aeromonas, resistance, virulence