Detection of Group B Streptococcus in Brazilian pregnant women and antimicrobial susceptibility patterns

Abstract

Group B Streptococcus (GBS) is still not routinely screened during pregnancy in Brazil, being prophylaxis and empirical treatment based on identification of risk groups. This study aimed to investigate GBS prevalence in Brazilian pregnant women by culture or polymerase chain reaction (PCR) associated to the enrichment culture, and to determine the antimicrobial susceptibility patterns of isolated bacteria, so as to support public health policies and empirical prophylaxis. After an epidemiological survey, vaginal and anorectal specimens were collected from 221 consenting laboring women. Each sample was submitted to enrichment culture and sheep blood agar was used to isolate suggestive GBS. Alternatively, specific PCR was performed from enrichment cultures. Antimicrobial susceptibility patterns were determined for isolated bacteria by agar diffusion method. No risk groups were identified. Considering the culture-based methodology, GBS was detected in 9.5% of the donors. Twenty five bacterial strains were isolated and identified. Through the culture-PCR methodology, GBS was detected in 32.6% specimens. Bacterial resistance was not detected against ampicillin, cephazolin, vancomycin and ciprofloxacin, whereas 22.7% were resistant to erythromycin and 50% were resistant to clindamycin. GBS detection may be improved by the association of PCR and enrichment culture. Considering that colony selection in agar plates may be laboring and technician-dependent, it may not reflect the real prevalence of streptococci. As in Brazil prevention strategies to reduce the GBS associated diseases have not been adopted, prospective studies are needed to anchor public health policies especially considering the regional GBS antimicrobial susceptibility patterns.

Group B Streptococcus detection in pregnant women via culture and PCR methods

“…In previous studies, the prevalence indexes for GBS in Brazil (14.6% to 32.6%) [13][14][15][16][17] were similar to those in countries that have adopted universal laboratory screening and maternal intrapartum antibiotic prophylaxis (10% to 30%); however, these values could potentially vary greatly by geographic location, sociodemographic and clinical characteristics, and the detection technique employed.…”

“…This colonization is a dynamic condition and represents the main risk factor for early neonatal infection. Notably, the international literature reports maternal GBS colonization rates of 6.5-36.0% in Europe 6,7 , 10.0-30.0% in North America 2,8 , 16.5-31.6% in African countries 9 , and 1.4-36.7% in South America, including Brazil [10][11][12][13] , Chile 14 , Peru 15 , and Argentina 16 .…”

<b> COLONIZATION PREVALENCE AND SUSCEPTIBILITY OF Streptococcus agalactiae IN PREGNANT WOMEN AT HUSM </b>

“…14 Since 2002, the CDC emphasizes the universal search for GBS colonization rather than the protocol based on risk factors, once studies showed that this strategy was more effective to define the use of intrapartum chemoprophylaxis, especially taking into account that many colonized pregnant women did not have risk factors for newborn infection. 1,5,14,15 In this context, studies that evaluate the rate of GBS colonization have been performed worldwide and the prevalence rates are variable: 8.6% in Mexico in 1999; 16 10.6% in Turkey in 2000, 17 9.1% in Iran in 2003, 5 7.6% inArgentina between 2004 and 2006. 18 In Brazil, these rates have become even higher.…”

“…Erythromycin and clindamycin are the drugs of choice for prophylaxis in women colonized by GBS who are allergic to penicillin. 1 Although most strains are susceptible to penicillin, 14,15,20,23,24 the increased use of erythromycin and clindamycin in patients allergic to penicillin or for the prevention and treatment ofother infections, has shown growth rates of GBS resistance to these antimicrobial agents in many countries, including Brazil. 15,20 A study made from 1994 to 1999 in Rio de Janeiro found in colonized women 5.4% and 1.1% of GBS resistance to erythromycin and clindamycin, respectively.…”

“…1 Although most strains are susceptible to penicillin, 14,15,20,23,24 the increased use of erythromycin and clindamycin in patients allergic to penicillin or for the prevention and treatment ofother infections, has shown growth rates of GBS resistance to these antimicrobial agents in many countries, including Brazil. 15,20 A study made from 1994 to 1999 in Rio de Janeiro found in colonized women 5.4% and 1.1% of GBS resistance to erythromycin and clindamycin, respectively. 25 15 In relation to susceptibility of four pregnant women colonized by GBS in the present study, we found no resistance to the tested antimicrobials.…”