Open AccessStored‐product insects carry antibiotic‐resistant and potentially virulent enterococci
Author(s) -
Channaiah Lakshmikantha H.,
Subramanyam Bhadriraju,
McKinney Leland J.,
Zurek Ludek
Publication year - 2010
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2010.00949.x
Subject(s) - biology , enterococcus hirae , tetracycline , enterococcus faecalis , enterococcus , microbiology and biotechnology , kanamycin , virulence , enterococcus faecium , gene cassette , ampicillin , antibiotic resistance , antibiotics , gene , escherichia coli , genetics , integron
A total of 154 enterococcal isolates from 95 stored‐product insects collected from a feed mill, a grain storage silo, and a retail store were isolated and identified to the species level using PCR. Enterococcus casseliflavus represented 51% of the total isolates, followed by Enterococcus gallinarum (24%), Enterococcus faecium (14%), Enterococcus faecalis (7%), and Enterococcus hirae (5%). Many isolates were resistant to tetracycline (48%), followed by streptomycin (21%), erythromycin (14%), kanamycin (13%), ciprofloxacin (12%), ampicillin (4%), and chloramphenicol (<1%). Enterococci carried genes coding for virulence factors, including the gelatinase gene gelE (26% of isolates), an enterococcal surface protein gene esp (1%), and the cytolysin gene cylA (2%). An aggregation substance ( asa1 ) gene was detected in six out of 10 E. faecalis isolates and five of these were positive for the aggregation substance. Enterococci were positive for hemolytic (57% of isolates) and gelatinolytic (23%) activity. The filter‐mating assay showed that the tetracycline resistance gene, tetM , was transferable among E. faecalis by conjugation. These data demonstrated that stored‐product insects can serve as potential vectors in disseminating antibiotic‐resistant and potentially virulent enterococci.