Detection of metallo-beta-lactamases-encoding genes in environmental isolates of Aeromonas hydrophila and Aeromonas jandaei.
OBJECTIVE
To determine the prevalence and expression of metallo-beta-lactamases (MBL)-encoding genes in Aeromonas species recovered from natural water reservoirs in southeastern Brazil.


RESULTS
Eighty-seven Aeromonas isolates belonging to Aeromonas hydrophila (n = 41) and Aer. jandaei (n = 46) species were tested for MBL production by the combined disk test using imipenem and meropenem disks as substrates and EDTA or thioglycolic acid as inhibitors. The presence of MBL genes was investigated by PCR and sequencing using new consensus primer pairs designed in this study. The cphA gene was found in 97.6% and 100% of Aer. hydrophila and Aer. jandaei isolates, respectively, whereas the acquired MBL genes bla(IMP), bla(VIM) and bla(SPM-1) were not detected. On the other hand, production of MBL activity was detectable in 87.8% and 10.9% of the cphA-positive Aer. hydrophila and Aer. jandaei isolates respectively.


CONCLUSIONS
Our results indicate that cphA seems to be intrinsic in the environmental isolates of Aer. hydrophila and Aer. jandaei in southeastern Brazil, although, based on the combined disk test, not all of them are apparently able to express the enzymatic activity.


CONCLUSIONS
These data confirm the presence of MBL-producing Aeromonas species in natural water reservoirs. Risk of waterborne diseases owing to domestic and industrial uses of freshwater should be re-examined from the increase of bacterial resistance point of view.
Public Health Laboratory, School of Public Health, University of São Paulo, São Paulo, Brazil. liviabalsalobre@usp.br
L C
LC
Balsalobre
M
M
Dropa
N
N
Lincopan
E M
EM
Mamizuka
G R
GR
Matté
M H
MH
Matté
D000333:Aeromonas / Q000201:enzymology* / Q000302:isolation & purification; D016980:Aeromonas hydrophila / Q000201:enzymology / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001938:Brazil; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005798:Genes, Bacterial; D008826:Microbial Sensitivity Tests / Q000379:methods; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D017422:Sequence Analysis, DNA; D014871:Water Microbiology; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D001618:beta-Lactamases; C082063:cphA protein, Aeromonas hydrophila