Isolation and Antibacterial Suseptibility pattern of STREPTOCOCCUS AGALACTIAE in pregnant women in Adigrat Zonal Hospital and Adigrat Health Center, Tigray,Ethiopia.
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Date
2012-06
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Addis Ababa University
Abstract
Back ground: S. agalactiae which are group B Streptococci asymptomatically colonize the vaginal or rectal areas of 10 to 30 % of pregnant women. In these women, S. agalactiae may cause preterm labor or membrane rupture, as well as urinary tract infections, chorioamnionitis, postpartum endometritis, postpartum wound infection, septic pelvic thrombophlebitis, endocarditis and sepsis. These bacteria is a major cause of invasive disease at all ages and is the most frequent cause of serious bacterial sepsis, including neonatal meningitis.
Objective: This study was undertaken to determine the carriage rate of S. agalactiae and to assess their antimicrobial susceptibility pattern. An attempt has been also made to identify the possible risk factors related with S. agalactiae colonization.
Methods: Rectal and vaginal swabs were obtained from 150 pregnant women at 35-37 weeks of gestational period that attended anti natal clinic at Adigrat Zonal Hospital and Adigrat Health Center. The specimen was cultured on selective CHROMagar StrepB and incubated aerobically at 37o c for 18-24 hours. Suspected colony of S. agalactiae mauve colony (pink color) was confirmed by gram stain, catalase test, Christie, Atkins, MunchPeterson (CAMP) testing and latex agglutination (serological) test. In cases of positive
cultures obtained, antibiotic susceptibility tests were carried out on all S. agalactiae isolates using the disc diffusion technique on Mueller-Hinton agar supplemented with 5% sheep blood and incubated at 37 0 c for 20-24 hours in 5% co. A univariate and multivariate binary logistic regression model was used to ascertain the association between the frequencies of colonization in relation to the different variables. 2
Results: Seventeen of the study participants (11.3%) were colonized by S. agalactiae. Thirteen (76.5%) of the isolates were from health center and 4(23.5%) werfrom hospital. The study revealed a higher colonization rate among the age group 21 to 30 years (76.5%) but one pregnant woman with S. agalactiae was identified (5.9%) in women aged lesser than or equal to 20 years. Bacterial resistance was not detected against ampicillin, penicillin G, amoxacilline and vancomycin, whereas 11.8% and 17.6% of the isolates were resistant to TMerythromycin and clindamycin respectively. Intermediate susceptibility was also detected in 2 isolates (11.8%) against erythromycin and in 2 isolates (11.8%) against clindamycin. By multi variant logistic regression analysis, Prolonged rupture of membrane was associated with a higher colonization rate of S. agalactiae (OR=5.864, 95% CI= 1.395 – 24.643, Pvalue=0.016). No significant association was identified between S. agalactiae colonization rates with other socio- demographic/gynecological characteristic of the pregnant women.
Conclusion: The carriage rate of S. agalactiae in the study area was 11.3%. High S.agalactiae isolates were detected from Adigrat Health Center. Prolonged rupture of membrane was strongly associated with the colonization of S. agalactiae. Based on the finding, penicillin G was the best antibiotic for the treatment of S. agalactiae. Out of the isolates 11.8% were resistance to erythromycin and 17.6% were resistance to clindamycin Common resistance to erythromycin and clindamycin was seen in two isolates.
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Keywords
S. agalactiae, Antibiotic susceptibility pattern, Pregnancy, Colonization,Ethiopia.