Recently Streptococcus suis. a zoonotic pathogen, was identified as the leading cause of bacterial meningitis in adults admitting to Hospital for Tropical Diseases, Ho Chi Minh city. Systematic data on the antimicrobial resistance of S. suis strains are not available. The article studied antimicrobial resistance and the resistance determinants in S. suis isolated from adult patients with meningitis. S. suis strains were investigated for their susceptibility to six antimicrobial agents. Strains were screened for the presence of tetracycline and erythromycin resistance determinants. The localization of tetracycline resistance gene tet(L) was determined by Southern blotting. The results showed a significant increase in multi drug resistance in S. suis strains isolated from patients over 11 years. The authors identified tet(M), tet(O), tet(W) and tet(L) and confirmed their expression in tetracycline resistance strains. The presence and expression of tet(L) in S. suis strains have not been reported. All tet(M) genes were associated with a Tn916-like transposon. The authors identified the co-expression of more than one tetracycline resistance genes in strains with a minimum inhibitory concentration (MIC) of tetracycline of or = 64 mg/l. The study suggested the presence of multiple tetracycline resistance determinants in S. suis and their co-expression could help those strains to resist with high concentration of antibiotic.