Group B Streptococci - Examination of Swab

The group B streptococci, also known as Streptococcus agalactiae, is an extremely common bacteria that normally colonize the vaginal regions, intestinal and rectal women. The Strep B does not usually cause illness in healthy people but can cause complications in pregnant women and be transmitted to the baby during delivery.

Group B streptococci
Group B streptococci
 


What is the Streptococcus group B


Group B streptococci (Streptococcus agalactiae) is a common bacterium, present in the genital region of 1 in 3 pregnant women. The Streptococcus agalactiae is usually harmless in adults and in healthy individuals, but can cause serious illness in infants and people with compromised immune systems, including patients in this group with severe diabetes, cancer and liver problems.

Although it is usually found in the female genital area, the group B Streptococcus is not an STD, ie is not a bacterium transmitted sexually. Most women with colonized vaginal area was contaminated by streptococci that came from your own bowel or rectal area.

In newborns, infection with Streptococcus agalactiae may still occur in the womb, by invasion of the amniotic fluid, popularly known as bag of water, or only at delivery, during passage through the birth canal. The latter route is the more common.

The Strep B is different from other species of Streptococcus that normally cause disease, such as pneumonia, meningitis, tonsillitis, scarlet fever, impetigo, etc.

Examples of different Streptococci Streptococcus agalactiae


1. The group B Streptococcus can even cause pneumonia or meningitis in infants, but the species Streptococcus more related to such infections in adults is Streptococcus pneumoniae, also known as pneumococcus.

2. Streptococcus viridans is another species, different from group B streptococci, which usually related to infective endocarditis.

3. Strep Group A, known as Streptococcus pyogenes is responsible for several diseases, including:
  • Pharyngitis and tonsillitis
  • Erysipelas
  • Scarlet fever
  • Impetigo
  • Rheumatic fever

Infection with group B streptococci in pregnancy


Infection with Streptococcus agalactiae during pregnancy is associated with a variety of potential risks for both the mother and the baby.

Urinary tract infection by Streptococcus agalactiae in pregnancy


Between 10% to 30% of pregnant women have colonization of the urine by bacteria Streptococcus agalactiae. In some of these pregnant women, the bacterium causes infection of the bladder, known as cystitis and pyelonephritis, which is an infection of the kidneys. Most patients, however, does not present urinary tract infection, colonization only urine by group B streptococci

The problem is that asymptomatic bacteriuria, the name given to the simple presence of bacteria in the urine without signs or symptoms of urinary tract infection is a major risk factor for pregnancy complications such as premature birth, miscarriage and infection of the amniotic fluid.

Amniotic fluid infection by Streptococcus agalactiae


Infection of the bag of water, called chorioamnionitis in medicine, is a bacterial invasion of the amniotic fluid, fetal membranes and placenta. The signs and symptoms of chorioamnionitis include fever, pain in the uterus, increased fetal heart rate and the presence of pus in aminótico liquid.

Infection of the amniotic fluid usually occurs during rupture of the bag at the beginning of labor in women colonized with Strep B. prolonged delivery works, with several hours, or cases of premature rupture of the bag, they are at greater risk. However, chorioamnionitis may arise before the rupture of the bag of water, as in cases of pregnant women with urinary tract infection, especially pyelonephritis.

Infection of the uterus by Streptococcus agalactiae


Infection of the lining of the uterus, called endometritis, is a complication that can occur after delivery of pregnant women infected with streptococcus group B. Abdominal pain, fever and uterine bleeding are signs and symptoms that suggest an infection in the postpartum period.

Infection in the newborn by group B streptococci


Despite the mother's risk for developing complications Streptococcus agalactiae, the major concern is always the baby contamination during delivery. The transmission of the bacterium usually occurs after the rupture of the bag or during the passage of the baby through the birth canal.

The complications of neonatal infection can occur early in the early hours of the baby's life, or late, only weeks after delivery.

The early infection of the newborn by group B streptococci is one that occurs within the first 7 days of life, usually within the first 24 hours, manifested as of pneumonia, meningitis and sepsis without a defined starting point.

Fever, difficulty breastfeeding and breathing difficulties are the most common symptoms in this type of infection. Seizures, muscle weakness or stiffness may also occur. Mortality in the early cases is about 3% in babies born over 37 weeks and 20% in premature infants.

Late infection of the newborn by group B streptococci is one that occurs after the first week of life. Sepsis and meningitis are the most common presentations. Mortality in later cases is about 2% in babies born more than 37 weeks and 6% in premature infants.

It is important to note that not every baby born to mothers colonized with group B streptococci will present problems. In fact, only 1 in 200 are infected and develop the disease.

Diagnosis of group B streptococci


To prevent neonatal infection by group B streptococci is important that the bacteria be identified and treated before labor. During pregnancy, all pregnant women are subjected to an examination of urine culture looking for bacteria in the urine. If bacteriuria is identified, i.e., presence of bacteria in urine, the obstetrician establish appropriate antibiotic treatment to eliminate them.

Between the 35th and 37th week of gestation usually do obstetricians examination swab, which is to obtain the material of the vagina and anus with a kind swab to search for the presence of Streptococcus group B.

If the test is positive, it means that the mother is settled. Immediately, however, there is high risk or to the mother or the fetus because the baby contamination occurs, the vast majority of cases, only at delivery. Being colonized by Streptococcus agalactiae only means that will be necessary antibiotic administration during labor to prevent transmission of the bacteria to the fetus.

The swab test is only done in late pregnancy because the colonization of the vagina by the Strep B may disappear alone during pregnancy. And even if it is treated early in pregnancy, the bacteria can return over the months. In addition, except for cases of urinary tract infection, the vast majority of colonized women have no complications during pregnancy. So if the urine test is negative, have the bacteria during pregnancy causes no major problems. The most important is whether the group B streptococci are present at the time of delivery, not months before.

The collection of vaginal and rectal stuff is painless and the result is ready in 2 or 3 days. It is not recommended shower or intimate hygiene before collection.

Treatment of group B streptococci


Every woman with positive swab test should be treated with antibiotics at delivery. No antibiotics, about 1 in every 200 babies is sick with Streptococcus agalactiae . With the use of antibiotics, the incidence drops to 1 in 4000 newborns, making it currently the neonatal infection by group B streptococci a rare event.

The antibiotic is administered intravenously during labor. The two most commonly used are penicillin or ampicillin, which must be administered every 4 hours until the baby's birth.

Treatment with antibiotics need not be done if the delivery is cesarean and no rupture of the bag of waters. In this case, there is no risk of bacteria present in the vaginal canal to reach the baby. However, if the waters break before the cesarean section begins, the administration of antibiotics is indicated.

Both ampicillin as penicillin antibiotics are safe for the baby.

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