Xiaomei is a mother-to-be who is 37 weeks pregnant. Today, when she went to the hospital for an obstetric examination, she got her own screening report for “Group B Streptococcus”, but the test result was positive. Xiaomei puzzled: What is group B streptococcus? What effect does it have on yourself and your baby? What should I do if the test result is abnormal?
What is group B streptococcus
Group B Streptococcus (GBS) is a gram-positive streptococcus, a facultative anaerobic bacteria that often “lives” in the human reproductive tract and rectum, and is a conditional pathogen. Domestic and foreign studies have shown that 10%-30% of healthy expectant mothers can detect group B streptococcus, and expectant mothers who have detected group B streptococcus have a 40% to 70% probability of infecting the bacteria to their newborns during delivery. .
What are the hazards of group B streptococcus
Impact on pregnant women: It is
easy to cause urinary tract infection, pyelonephritis and bacteremia in pregnant women, and increase the risk of premature birth, amnionitis, endometritis and wound infections.
Impact on newborns:
The main transmission route of group B streptococcus is vertical transmission. If the expectant mother carries group B streptococcus, the fetus may be infected by inhaling the amniotic fluid that carries the bacteria or passing through the birth canal.
According to the time of neonatal infection with group B streptococcus, it can be divided into early invasive infection (within 7 days of birth) and late invasive infection (after 7 days of birth). Early invasive infections mainly cause pneumonia, sepsis, etc.; late invasive infections usually lead to local infections of the baby’s body, and meningitis can occur in severe cases.
When is the best time for screening
The “Guidelines for Pre-pregnancy and Pre-pregnancy Care (2018)” formulated by the Obstetrics Group of the Obstetrics and Gynecology Branch of the Chinese Medical Association pointed out that it is advisable to take the rectum (2 to 3 cm through the anal sphincter) and the lower 1/3 of the vagina at 35 to 37 weeks of pregnancy. Place secretions (collect one swab for each), and screen for group B streptococcus.
What to do if group B streptococcus is positive
Those who have given birth to fetuses infected with invasive group B streptococci; those who have group B streptococcal bacteremia at any stage during this pregnancy; those who have had a positive vaginal and rectal group B streptococcal screening results in the third trimester of pregnancy; labor Those who have not been screened for group B streptococci at the time of start-up; those who have not exceeded 37 weeks of pregnancy and the premature rupture of membranes lasted more than 18 hours must receive preventive anti-infective treatment.
The choice of antibacterial drugs depends on whether there is a history of penicillin allergy and the severity of the allergy. Penicillin G (natural penicillin) has a narrow antibacterial spectrum and is the drug of choice for pregnant women; ampicillin is a broad-spectrum antibacterial drug and is an alternative drug. People with a history of penicillin allergy but not immediate hypersensitivity can use cefazolin. Those who are allergic to penicillin and have immediate hypersensitivity reactions should be cautious in choosing antibacterial drugs, based on the results of drug susceptibility tests: if the strain is sensitive to both clindamycin and erythromycin, clindamycin should be used; For those who are sensitive to lindamycin and resistant to erythromycin, further drug-induced resistance tests are required. Clindamycin is selected for those who are negative, and clindamycin is selected for those who are positive or the strain is resistant to clindamycin, and those with unknown drug sensitivity Vancomycin.
It is worth noting that because oral antibacterial drugs are not effective against group B streptococcal infections, intravenous infusion of antibacterial drugs is generally used when the mother is “started” during childbirth or when the fetal membranes are ruptured. If the fetal membranes are intact, preventive anti-infective treatment is not required for those with positive culture of group B streptococci undergoing cesarean section.