Why we test before treating neonatal sepsis, and why we stop antibiotics

Neonatal sepsis is a serious blood infection in a baby in the first month of life. Doctors take a blood culture before starting antibiotics, then stop the antibiotics after about 36 to 48 hours if the culture shows no germs and the baby is well. Stopping early is not careless. It protects your baby and helps keep antibiotics working.

What is neonatal sepsis?

Neonatal sepsis is an infection that has spread into the bloodstream of a newborn and is affecting the whole body. It can become life threatening within hours.

Newborns are at higher risk because their immune system is still learning. Premature babies get fewer protective antibodies from their mothers before birth. Their skin is thin, and in the NICU, lines and tubes can give germs a way in. In a large Delhi study, nearly a quarter of deaths among newborns admitted to intensive care were due to sepsis.¹

What are the signs of sepsis in a newborn?

The signs are often vague. A baby with sepsis may simply feed poorly, become sleepy, or feel cold rather than hot.

A large study of young infants in six countries, including India, found that these signs best predicted serious illness in the first week of life:²

• Difficulty feeding.
• Fits (convulsions).
• Moving only when touched, or not at all.
• Breathing 60 times a minute or more.
• Severe chest drawing in.
• Temperature of 37.5 degrees C or more, or below 35.5 degrees C.

Grandmothers and nurses often sense that "something is not right" before any test shows it. Dr Dutta takes that seriously.

What is the difference between early onset and late onset sepsis?

Early onset sepsis starts in the first 72 hours of life. Late onset sepsis starts after that.

Early infections are often linked to the birth: waters broken for a long time before delivery, infection in the mother around labour, or early labour that starts on its own.³ Late infections in NICU babies usually come from hands, equipment or lines, and in babies at home from the community. In the Delhi DeNIS study, the germs causing early and late infections were much the same, which suggests that many "early" infections in Indian hospitals may also be picked up around birth or in the unit.¹

Which germs cause sepsis in Indian newborns?

In Indian hospital studies, gut type bacteria called Gram-negative bacteria cause most cases, not the group B streptococcus that is common in Western countries.

The Delhi Neonatal Infection Study (DeNIS), published in the Lancet Global Health in 2016, followed more than 13,000 babies admitted to three Delhi hospitals. Nearly two thirds of the germs grown were Gram-negative, mainly Acinetobacter (22 percent), Klebsiella (17 percent) and E. coli (14 percent).¹ This matters because it changes which antibiotics will work.

Why is a blood culture taken before starting antibiotics?

A blood culture is the test that shows whether germs are growing in the blood, and which antibiotics will kill them. It must be taken before the first dose, because antibiotics can stop germs growing in the bottle.

NICE, the UK guideline body, advises taking a blood culture before the first antibiotic dose in any baby who may have an infection.³ The sample takes a minute, and antibiotics follow straight away, so it does not delay treatment. If the culture is skipped, we may never know whether the baby had an infection at all.

How much blood is needed for a newborn blood culture?

About 1 mL or more. A very small sample can miss an infection.

A laboratory study showed that when there are only a few germs in each millilitre of blood, which is common in newborns, 0.5 mL is not enough. The authors advised 1 to 2 mL to find the germs reliably.⁴ If your baby needs a culture, it helps to know that the amount of blood really does matter.

How long does a blood culture take?

Most true infections show up within 36 hours. Germs that grow later are often harmless skin contaminants.

In a large American study of late onset infections, 85 percent of positive cultures were flagged by 36 hours, and almost 94 percent when common skin germs were left out.⁵ An Italian study of early infections in bigger babies found all true positives within 48 hours.⁶ That is why a negative culture at 36 to 48 hours is strong reassurance.

Is a CRP blood test enough to diagnose sepsis?

No. CRP and blood counts help, but on their own they can neither prove nor rule out sepsis in a newborn.

American guidance says laboratory tests alone are not accurate enough to guide decisions about newborn sepsis.^7,8 CRP can rise after a normal birth and may be normal early in an infection. NICE advises measuring CRP at the start and using later readings together to judge how likely infection is.³

Why did the doctors stop antibiotics after two days?

Because the blood culture showed no germs and your baby was well. Continuing would add risk without benefit.

NICE advises stopping antibiotics at 36 hours if the culture is negative, the first suspicion of infection was not strong, the baby looks well and the CRP results are reassuring.³ Many families feel a "full course" is safer, but in very small babies longer courses without proven infection have been linked to more NEC (a serious bowel illness), more late infections and more deaths.^9,10 Stopping on time is part of good treatment.

How long are antibiotics given if the culture is positive?

Usually 7 days for a blood infection, and longer for meningitis or certain germs.³

NICE advises a 7 day course for a positive culture, or for a negative culture when sepsis was strongly suspected, and a longer course if the baby has not fully recovered or the germ needs it.³ Once the germ and its sensitivity are known, the doctors may switch to a narrower antibiotic that targets it.

Does every baby with a risk factor need antibiotics?

No. Many well looking babies born near term can be watched closely instead of being given antibiotics.

A tool called the Kaiser Permanente sepsis calculator combines birth risk factors with how the baby looks. In over 200,000 babies born at 35 weeks or later, using it cut antibiotic use in the first day from 5.0 to 2.6 percent, with no rise in harm.¹¹ NICE allows units to use it for babies born after 34 weeks, as part of an audit.³ Premature babies are different, and doctors are more cautious with them.⁸

Why is antibiotic resistance a problem in Indian NICUs?

Many germs in Indian NICUs no longer respond to common antibiotics. Some respond to only one or two last line drugs.

In the DeNIS study, 82 percent of Acinetobacter, 54 percent of Klebsiella and 38 percent of E. coli were resistant to at least three classes of antibiotics.¹ Infections with these resistant germs accounted for a large share of deaths from sepsis.¹ Every unneeded course of antibiotics, in hospitals, clinics, chemist shops and farms, adds to this problem. That is one reason Dr Dutta stops antibiotics as soon as it is safe.

How can parents help prevent infection in the NICU?

Clean hands, breast milk and skin to skin care are the three things parents can do every day.

• Wash your hands or use alcohol rub every time before and after touching your baby. Remind staff too.
• Give your breast milk, especially the first colostrum.
• Do kangaroo care. Pooled trials found it lowered serious infection in low birth weight babies.¹²
• Keep visitors with fever, cough, loose motions or skin infections away.

How can I protect my newborn from infection at home?

Keep hands clean, feed breast milk, and limit visitors in the first weeks. Never put anything on the cord stump or in the eyes unless your doctor advises it.

Kajal, oil, ash or cow dung on the cord or eyes can carry germs. Keep the cord clean and dry. Anyone who holds the baby should wash their hands first, including grandparents and the household help. Babies who are unwell should be seen early, not after a night of waiting.

When should I take my newborn to hospital?

Go the same day, without waiting, if your baby has any of these signs. In the first weeks, sepsis can get worse within hours, so do not wait to see if it settles. These signs predict serious illness in young infants:²

• Feeding poorly or refusing feeds.
• Unusually sleepy, floppy or hard to wake.
• Temperature of 37.5 degrees C or more, or below 35.5 degrees C.
• Breathing 60 times a minute or more, grunting or chest drawing in.
• Fits, stiffening or jerking.
• Pale, mottled or blue skin.
• Redness spreading from the belly button, or pus.
• A bulging soft spot on the head.