Distribution of serotypes and evaluation of antimicrobial susceptibility among human and bovine Streptococcus agalactiae strains isolated in Brazil between 1980 and 2006

Abstract

Streptococcus agalactiae is a common agent of clinical and subclinical bovine mastitis and an important cause of human infections, mainly among pregnant women, neonates and nonpregnant adults with underlying diseases. The present study describes the genetic and phenotypic diversity among 392 S. agalactiae human and bovine strains isolated between 1980 and 2006 in Brazil. The most prevalent serotypes were Ia, II, III and V and all the strains were susceptible to penicillin, vancomycin and levofloxacin. Resistance to clindamycin, chloramphenicol, erythromycin, rifampicin and tetracycline was observed. Among the erythromycin resistant strains, mefA/E, ermA and, mainly, ermB gene were detected, and a shift of prevalence from the macrolide resistance phenotype to the macrolide-lincosamide-streptogramin B resistance phenotype over the years was observed. The 23 macrolide-resistant strains showed 19 different pulsed-field gel electrophoresis profiles. Regarding macrolide resistance, a major concern in S. agalactiae epidemiology, the present study describes an increase in erythromycin resistance from the 80s to the 90s followed by a decrease in the 2000-2006 period. Also, the genetic heterogeneity described points out that erythromycin resistance in Brazil is rather due to horizontal gene transmission than to spreading of specific macrolide-resistant clones.

In vitro antimicrobial susceptibility and genetic resistance determinants of Streptococcus agalactiae isolated from mastitic cows in Brazilian dairy herds

“…In the United States and Europe, resistance rates of approximately 4-50% have been reported (DIPERSIO; DIPERSIO, 2006;DOGAN et al, 2005;GUÉRIN-FAUBLÉE et al, 2002;SADOWY et al, 2010), while in Brazil, estimates have been lower than 10% (CORRÊA et al, 2011;DUARTE et al, 2004DUARTE et al, , 2005PALMEIRO et al, 2010). However, of the Brazilian bovine isolates examined by Pinto et al (2013), 27.6% were resistant to this antibiotic, a higher value than that recorded in the present work (19.5%).…”

“…High rates of tetracycline resistance (60-90%) have been reported among both human and bovine S. agalactiae isolates (DOGAN et al, 2005;DUARTE et al, 2004;GAO et al, 2012;PINTO et al, 2013;RATO et al, 2013). In the current work, resistance to this antimicrobial was found to be approximately 35.6%.…”

Indirect enzyme-linked immunosorbent assay method based on Streptococcus agalactiae rSip-Pgk-FbsA fusion protein for detection of bovine mastitis

“…Although numerous pathogenic microorganisms have been implicated in BM, Streptococcus agalactiae (SA) is the main causal pathogen of this disease (Bramley and Schultze 1991, Baseggio et al 1997, Pinto et al 2013, Wang et al 2015a, Bosward et al 2016. The detection rate of SA in mastitis milk samples from cows in Inner Mongolia of China was reported to be 70%, posing great hazards to human and animal health (Andersen et al 2003, Duarte et al 2004, Verhoeven et al 2014.…”

Streptococcus agalactiae in Brazil: serotype distribution, virulence determinants and antimicrobial susceptibility

“…Four serotypes (Ia, II, III and V) are usually the most frequently isolated in the United States and in some European countries [6-8], while serotypes VI to IX are rarely described [4,9]. In Brazil, the occurrence of serotypes Ia, Ib, II, III, IV and V has been described in a few studies conducted with isolates originated from the South and the Southeast regions [10-15]. …”

“…Clindamycin or erythromycin is recommended for GBS intrapartum prophylaxis for penicillin-allergic women with high risk of anaphylaxis or when therapeutic failure is suspected [19]. However, increasing rates of resistance to these antibiotics have been detected in several regions of the world, including Europe [8,20], Asia [21], North America [22-24], and South America [11,13,15,25]. …”