Antimicrobial Resistance of Streptococci Isolated from Mastitic Bovine Milk Samples in Korea

Abstract

The aim of this study was to determine the antimicrobial resistance of streptococci isolated from mastitic bovine milk samples. A total of 178 isolates belonging to 6 different Streptococcus species were examined: S. uberis (n = 99), S. bovis (n = 30), S. oralis (n = 24), S. salivarius (n = 13), S. intermedius (n = 7), and S. agalactiae (n = 5). Only 8.9% (16/178) of the isolates were susceptible to all antimicrobial agents tested in this study, and S. agalactiae and S. intermedius isolates were all resistant to at least 1 antimicrobial agent tested. Overall, the most frequently observed resistance was to tetracycline (61.2%), followed by lincomycin (43.2%), gentamycin (35.3%), oxacillin (34.3%), and erythromycin (28.6%). Cephalothin and penicillin were the only antimicrobial agents to which most of the streptococci (>or=92%) were susceptible. Wide differences in the prevalence of resistance are apparent among the individual species: S. salivarius displayed exceptionally high resistance to cephalothin (23.0%) and oxacillin (76.9%) and S. agalactiae (20%) and S. intermedius (14.2%) to penicillin. Streptococcus salivarius and S. agalactiae were all susceptible to erythromycin, but others showed various rates of resistance ranging from 12.5% to 42.8%. Resistance to 3 or more of 7 antimicrobial agents was observed in all species (37.6%, 67/178).

Antimicrobial resistance and virulence-related genes ofStreptococcusobtained from dairy cows with mastitis in Inner Mongolia, China

“…Decreased susceptibility to penicillin has been reported previously (Guérin-Faublée et al, 2002;Rossitto et al, 2002). In contrast to the rate of penicillin resistance (approximately 10%) reported (Nam et al, 2009), the high rate of Streptococci in the present study was resistant to penicillin in the area. b-Lactams are known as the first-line antimicrobial agents when treating streptococcal udder infections (Denamiel et al, 2005).…”

“…Meanwhile, 3.7% (3/81) were resistant to seven antimicrobial agents. The previous report from Korea stated that about 65% of the isolates were resistant to two or more antimicrobial agents, and 37.6% were resistant to three or more of seven antimicrobial agents tested (Nam et al, 2009). The results suggest that the abuse of antibiotics is very serious, and resistance to many antibiotics has reached a high level, especially multiple resistance in Inner Mongolia region than Korea (Nam et al, 2009).…”

Genomics, evolution, and molecular epidemiology of the Streptococcus bovis / Streptococcus equinus complex (SBSEC)

“…Several ruminant animal diseases such as mastitis, bacteraemia and sepsis are associated with the SBSEC, albeit at low frequency as causative agent Nam et al, 2009;Seimiya et al, 1992). They are suggested to be an opportunistic cause of mastitis due to lower virulence and infectivity than the predominant mastitis agent Streptococcus uberis (Garvie and Bramley, 1979;Nam et al, 2009).…”

“…They are suggested to be an opportunistic cause of mastitis due to lower virulence and infectivity than the predominant mastitis agent Streptococcus uberis (Garvie and Bramley, 1979;Nam et al, 2009). Among the SBSEC, especially S. bovis biotype II strains were detected in mastitis milk samples and corresponding milk men (Kateete et al, 2013).…”

Characterization of High-Level Daptomycin Resistance in Viridans Group Streptococci Developed upon In Vitro Exposure to Daptomycin

“…Historically, these organisms have been relatively susceptible to most antibiotics. However, the frequency of multidrug resistance has been increasing (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). Much of the resistance and virulence associated with these organisms can be exchanged among multiple streptococcal species via horizontal transfer of genetic material (13,18,19).…”