High frequency of hemolytic and cytotoxic activity in Aeromonas spp. isolated from clinical, food and environmental in Rio de Janeiro, Brazil.
Molecular study of aerolysin and cytotonic enterotoxin genes by PCR and colony blot hybridization was performed in 117 strains of Aeromonas spp. isolated from different sources. Homogeneous distribution of these genes in A. hydrophila complex strains was observed. For A. caviae and A. sobria complex strains, aerolysin genes were more frequent than cytotonic enterotoxins genes. Of 64 A. caviae complex strains, only one (1.5%) amplified the 451 bp product for the aer gene, however, the same primers detected a 400 bp product in 50 (78%) strains. This product was sequenced and had two short regions with homology to several hemolysin genes. The genotype aer (+)/aerA(+)/hly (+)/ast (+)/alt (+) was detected in six A. hydrophila strains from food and environmental source. The most common genotype found in A. hydrophila strains was hly (+) (85%) and aerA(+) (78.7%), while in A. caviae complex strains was aerA(+) (32.8%). All A. veronii complex sobria strains were aer (+)/aerA(+). All A. caviae and A. hydrophila were positive when tested with aer probe using the colony blot test. Thirty-seven percent of A. hydrophila and 53% of A. caviae tested were positive for ast probe. Eighty-nine percent of samples were cytotoxic in Vero cells. Our data demonstrated that Aeromonas spp. can harbor and express virulence genes and reinforce the potential of Aeromonas as a human pathogen.
Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Avenida 28 de setembro 87, 3o andar, Fundos, RJ, Brazil.
Magda C B
MC
Castilho
Tatiana L A
TL
Castro
Viviane S
VS
Araújo
Rosemere S
RS
Trajano
Paula A
PA
Santos
Paula M C
PM
Pimenta
Kely
K
Lucheze
Janyne T B
JT
Melo
Aline M
AM
Gonçalves
Raquel T
RT
Nogueira
Maria Graças
MG
de Luna
Angela C
AC
Freitas-Almeida
D000333:Aeromonas / Q000302:isolation & purification* / Q000472:pathogenicity*; D001427:Bacterial Toxins / Q000235:genetics*; D001938:Brazil; D016923:Cell Death; D004783:Environmental Microbiology; D005516:Food Microbiology; D005838:Genotype; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology*; D006461:Hemolysis; D006801:Humans; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D037521:Virulence Factors / Q000235:genetics*
D001427:Bacterial Toxins; D037521:Virulence Factors