Introduction

Streptococcus is a diverse group of bacteria that form part of the normal microbiome in humans and animals. However, some bacteria can cause serious diseases like rheumatic heart disease and pneumonia. Two bacterial species that cause severe infections in humans are Streptococcus pyogenes and Streptococcus pneumoniae. Other bacteria in this family include S. agalactiae, which causes neonatal infections, S. mutans which causes tooth decay, and S. mitis which is linked to bloodstream infections and pneumonia.¹

Types of streptococcal infections

Streptococcal infections are caused by two strains of bacteria, namely streptococcus A and streptococcus B. 

Group A streptococcal bacteria are known to cause skin and throat infections, including

• Sore throat
• Impetigo (i.e., skin infection with pus-filled blisters)
• Cellulitis (i.e., infection of the skin and the tissues below)
• Erysipelas (i.e., inflammation of the skin)
• Tonsillitis (i.e., severe throat infection)
• Scarlet fever (i.e., infection causing sore throat, fever and rash)

Group A streptococcal bacteria can enter the blood, muscle or fat tissue and cause invasive streptococcal infections, including:

• Bacteraemia (i.e., blood infection)
• Endocarditis (i.e., infection in the heart lining)
• Meningitis (i.e., inflammation in the brain and spinal cord inflammation)
• Peritonitis (i.e., inflammation of the intestine)
• Urinary tract infection
• Necrotising fasciitis (i.e., death of tissue under the skin)
• Streptococcal toxic shock syndrome (i.e., an infection causing low blood pressure and injury to organs like the kidneys)

Group B streptococcal (GBS) bacteria reside in human bodies harmlessly in most cases. GBS is usually a problem only in pregnant women, as the infection could spread to the baby; but it can also seriously affect newborn babies, old people, or severely ill people. A pregnant woman carrying this bacteria may not show any symptoms; hence, though GBS does not affect the pregnant woman, it can affect the baby around the time of birth. GBS infection is very rare during pregnancy or before labour. GBS can cause severe infections in newborn babies. These include:

1. Pneumonia (i.e., lung infection)
2. Sepsis (i.e., blood poisoning) 
3. Meningitis (i.e., infection of the fluid and lining around the brain)

This article focuses on group B streptococcal infections and their effect during pregnancy.

Spread of streptococcal infection

Some ways of the spread of the infection are as follows:

1. Streptococcal bacteria are spread by contact with someone with an infection or a carrier. Carriers are people who “carry” streptococcal bacteria on their skin, in the throat, vagina, bladder, or rectum but do not develop an infection
2. The bacteria can spread via droplets from the nose or throat of someone with an infection
3. Sometimes, the bacteria can enter the body via contaminated food, usually milk, milk products, and eggs
4. Sometimes bacteria enter via cuts in the skin
5. Health conditions like cancer and diabetes reduce immunity and make the person prone to infection. People on medications like steroids also have a greater risk of infection

The spread of bacteria can be controlled by following good hygiene practices, like hand washing, especially after coughing, sneezing, and before eating. Cuts and wounds should be kept clean, and signs of infection, like swelling, redness, pus, and pain in the area of the wound, should be monitored. 

Risk factors for a baby to develop GBS infection

A baby is at a higher risk of developing a GBS infection if:

1. The baby is born preterm, that is before the completion of 37 weeks of pregnancy. This risk increases with the baby being born earlier
2. The mother previously had a baby affected by GBS infection
3. The mother had a high temperature or other signs of infection during labour
4. The mother had a positive urine or swab test for GBS during the pregnancy
5. The mother’s water broke more than 24 hours before the baby was born

To reduce the risk of spread of infection to the baby, the following should be taken care of:

1. If the mother has a urine infection that is caused by GBS, the infection should be treated with antibiotics
2. The mother should be given antibiotics through a drip during labour if she:
   • Has had a GBS-positive swab or urine test
   • Has had a urine infection caused by GBS
   • Has previously had a baby diagnosed with GBS infection
   • Or develops any signs of infection during labour

3. If the mother is infected with GBS and her water breaks after 37 weeks of pregnancy, she would be made to undergo induction of labour straight away and be given antibiotics via a drip
4. If an uninfected mother undergoes labour before 37 weeks of pregnancy, she should still be given antibiotics through a drip

Does the baby have a GBS infection?

Babies with a GBS infection usually show symptoms in the first week after birth. However, there are cases when the baby can develop the infection until they turn 3 months old. The symptoms that indicate the onset of GBS within the first week are:

1. Noisy breathing or breathing requires hard work and effort
2. Being unresponsive or very sleepy
3. Crying inconsolably
4. Not feeding well
5. Body temperature is over or below normal
6. Changes in skin colour
7. Having an abnormally fast or slow heart rate
8. Low blood pressure (identified in the hospital)
9. Low blood sugar (identified in the hospital) 

Delay in diagnosis and treatment is serious and could prove to be fatal for a baby with a GBS infection. 

Tests and treatment for the baby

Tests to confirm that the baby has a GBS infection involve taking a sample of the baby’s blood, or fluid from the spinal cord (lumbar puncture). Once the GBS infection is confirmed, it is treated with antibiotics; this treatment will be stopped when there are no signs of infection for at least 36 hours and all tests are negative.

FAQs

How can an asymptomatic pregnant woman know if she has GBS?  

GBS can be detected during pregnancy only when one has vaginal or rectal swabs or a urine test.

Can antibiotics during labour prove to be harmful?

Sometimes women have side effects like diarrhoea. However, most of these side effects are temporary. Being allergic to antibiotics can be fatal and the healthcare professional should be informed of any known allergies. The mother can choose to not have antibiotics during labour. In this case, the baby is monitored closely as they are at a higher risk of developing a GBS infection.

Can a mother with a GBS infection still breastfeed?

Breastfeeding is considered safe for the new baby. It has not been shown to increase the risk of GBS infection, but it is beneficial to both the mother and the baby.

What is the incidence rate of GBS affecting the baby?

1 in 1750 pregnant women pass down the infection to their baby during labour; creating a small risk of miscarriage.

Summary

Streptococcal bacteria are a diverse group that includes species which are part of the normal microbiome in humans and animals. However, some bacteria can cause serious diseases like scarlet fever, rheumatic heart disease, and pneumonia. There are two groups of streptococcal infections: Group A streptococcal infections often cause skin and throat infections, while Group B streptococcus (GBS), which commonly resides in the body without causing harm, poses significant risks to newborns if passed from the mother during childbirth. 

Pregnant women can carry GBS without symptoms, but the bacteria can cause serious complications in newborns, such as pneumonia, sepsis, and meningitis. Screening for GBS during pregnancy can help prevent the spread of the infection to the baby. If GBS is found, antibiotics are given during labour to reduce the risk of infection.

GBS infections are rare but can be life-threatening in newborns. Babies are especially vulnerable if they are born prematurely, have a mother with a history of GBS infection, or if the mother’s water breaks prematurely. Symptoms of GBS in infants include difficulty breathing, poor feeding, and changes in skin colour or temperature. Early detection and treatment with antibiotics help manage GBS infections in newborns.

Good hygiene practices, like hand washing and keeping wounds clean, help prevent the spread of streptococcal infections. Pregnant women are encouraged to undergo GBS screening, and if necessary, receive appropriate antibiotic treatment during labour to protect their babies. Early diagnosis and prompt treatment of GBS infections in newborns are essential to prevent serious complications or death.