P3-112 Streptococcus infantarius Strains Isolated from Brazilian Goat Milk

Wednesday, August 6, 2014
Exhibit Hall D (Indiana Convention Center)
Karina M.O. dos Santos, EMBRAPA, Sobral, Brazil
Carliane Matos, EMBRAPA, Sobral, Brazil
Antonio D.S. Vieira, University of Săo Paulo, Săo Paulo, Brazil
Liana da Silva, EMBRAPA, Sobral, Brazil
Svetoslav Todorov, Universidade de Sao Păulo, Sao Păulo, Brazil
Introduction: Streptococcus infantarius is a species isolated from dairy products and infants and is considered as opportunistic pathogen.

Purpose: Are St. infantarius isolates able to survive in the human GIT, to compete with LAB and to present risk for consumption of contaminated milk?

Methods: Isolates K1-4 and K5-1, differentiated by RAPD-PCR have been investigated for their ability of aggregation to intestinal pathogens; de-conjugation of TCA, TDC, GCA and GDC; hydrophobicity; survival under conditions simulating the GIT; and resistance to antibiotics.

Results: Both St. infantarius showed good survival rates when exposed to simulating gastric and enteric conditions (86.9% and 69.9% for K1-4 and 25.9% and 68.6% for K1-5). Both St. infantarius were able to grow in presence of TDCA, TCA, GDCA or GCA, but did not show ability to de-conjugated bile-salts. St. infantarius K1-4 and K5-1 exhibited 25.4% and 89.9% hydrophobicity, and 67.9% and 23.0% auto-aggregation. St. infantarius K5-1 showed production of β-galactosidase, however, St. infantarius K1-4 was negative. The strain K1-4 showed resistance (MIC) to imepinem (0.5 µg/ml), vancomycin (2.0 µg/ml), ampicillin (0.25 µg/ml), clindamycin (4.0 µg/ml), tetracycline (0.25 µg/ml), erythromycin (0.25 µg/ml) and gentamicin (32 µg/ml). St. infantarius K5-1 presented similar resistance to antibiotics: imepinem (0.15 µg/ml), vancomycin (1.0 µg/ml), ampicillin (0.6 µg/ml), clindamycin (0.15 µg/ml), tetracycline (12 µg/ml), erythromycin (0.06 µg/ml) and gentamicin (32 µg/ml). High levels of co-aggregation with E. coli, L. monocytogenes, C. perfringens and Salmonella spp. have been recorded for both isolates.

Significance: According to the results, St. infantarius K5-1 present better potential to colonize and compete with GIT microflora compared to St. infantarius K1-4. Both strains presented resistance to the major groups of antibiotics. Milk contaminated with this two strains presenting a health risk since the studied St. infantarius strains presented good ability to survive to simulated GIT conditions and to be responsible for a chronicle GIT disorders.