Antibiotic susceptibility patterns and prevalence of group B Streptococcus isolated from pregnant women in Misiones, Argentina

Abstract

This study was performed to determine the susceptibility patterns and the colonization rate of Group B Streptococcus (GBS) in a population of pregnant women. From January 2004 to December 2006, vaginal-rectal swabs were obtained from 1105 women attending Dr. Ramón Madariaga Hospital, in Posadas, Misiones, Argentina. The carriage rate of GBS among pregnant women was 7.6%. A total of 62 GBS strains were randomly selected for in vitro susceptibility testing to penicillin G, ampicillin, tetracycline, levofloxacin, gatifloxacin, ciprofloxacin, quinupristin-dalfopristin, linezolid, vancomycin, rifampicin, trimethoprim- sulfametoxazol, nitrofurantoin, gentamicin, clindamycin and erythromycin, and determination of resistance phenotypes. No resistance to penicillin, ampicillin, quinupristin-dalfopristin, linezolid, and vancomycin was found. Of the isolates examined 96.8%, 98.3%, 46.8%, and 29.0% were susceptible to rifampicin, nitrofurantoin, trimethoprim-sulfametoxazol and tetracycline, respectively. Rank order of susceptibility for the quinolones was: gatifloxacin (98.4%) > levofloxacin (93.5%) > ciprofloxacin (64.5%). The rate of resistance to erythromycin (9.7%) was higher than that of other reports from Argentina. High-level resistance to gentamicin was not detected in any of the isolates. Based on our finding of 50% of GBS isolates with MIC to gentamicin equal o lower than 8 μg/ml, a concentration used in one of the selective media recommended for GBS isolation, we suggested, at least in our population, the use of nalidixic acid and colistin in selective media with the aim to improve the sensitivity of screening cultures for GBS carriage in women.

Antibiotic Susceptibilities of Group B Streptococci

“…While Resistance to quinolones has been described recently for GBS, An increase in resistance of GBS to quinolones has been reported (Quiroga et al, 2008;Topkaya et al, 2003;Kawamura et al, 2003). Compared the study which has been reported from Argentina the rate of ciprofloxacin resistance is higher in our study (Quiroga et al, 2008).…”

“…The increasing prevalence of macrolide resistance raises concern about the empirical use of these antibiotics for the prevention of GBS infections (Fluegge et al, 2004;Tünger et al, 2005). While aminopenicillins are still highly active against GBS in most susceptibility studies such as our study (Al-Sweih et al, 2005;Quiroga et al, 2008;De Mouy et al, 2001;Fluegge et al, 2004;Topkaya et al, 2003;Figueira-Coelho et al, 2004;Monique et al, 2006), resistance to erythromycin and clindamycin have been reported in many studies range from 0.7% to 21.4% for erythromycin and 1.7% to 17.5% for clindamycin (Betriu et al, 2003;Quiroga et al, 2008;Ölçü and Eşel, 2007;De Mouy et al, 2001;Fluegge et al, 2004;Topkaya et al, 2003;Figueira-Coelho et al, 2004). Compared to this studies which have been reported from our country and other countries, the rates of erythromycin and clindamycin resistance were concordant in our experience.…”

“…The incidence of group B streptococcal disease is also high in pregnant women and the elderly (Schrag et al, 2000). Penicillin and ampicillin are the drugs of choice for treatment of GBS infections, and clindamycin and erythromycin are the recommended alternatives for patients who are allergic to ß-lactam agents (Quiroga et al, 2008). Clindamycin and erythromycin resistance rates are 15-20 % and they are increasing worldwide (Ölçü and Eşel, 2007).…”

“…Clindamycin and erythromycin resistance rates are 15-20 % and they are increasing worldwide (Ölçü and Eşel, 2007). Widespread use of these antibiotics in various clinical conditions has potentated the emergence of antibiotic resistance (Quiroga et al, 2008).…”

Avaliação da atividade antimicrobiana do alho (Allium sativum Liliaceae) e de seu extrato aquoso

“…Os antibióticos habitualmente utilizados na quimioprofilaxia são penicilina ou ampicilina e, nos casos de alergia, eritromicina ou clindamicina (Quiroga et al, 2008).…”