Staph, MRSA and Breastfeeding

Staphylococcus aureus is the most common bacteria associated with infection in damaged nipples, mastitis or breast abscesses. An increasing number of Staphylococcus aureus bacteria (staph) are resistant to certain antibiotics and are known as methicillin or meticillin-resistant Staphylococcus aureus (MRSA). MRSA may directly affect a wound or be a more systemic infection (throughout the body). Some people are carriers of staph without having any symptoms of infection. This article looks at the recommendations for breastfeeding if a mother is diagnosed with staph or an MRSA infection.

Staphylococcus aureus infection

Staph is a common bacteria which may be found on the skin or in the nose 1. When a bacterial infection is found in cracked or damaged nipples, infective mastitis or an abscess, penicillin-resistant Staphylococcus aureus (staph or S. aureus) is the most likely bacteria to be cultured. Your doctor will prescribe antibiotic treatment (penicillinase-resistant penicillins) to deal with the infection but breastfeeding can continue.23

Many health workers are concerned about a possible risk of infection to the infant, especially if the milk appears to contain pus. They recommend manual expression, and discarding of the milk. However a number of studies have demonstrated that continuing to breastfeed is generally safe, even in the presence of Staph. aureus.

The infant should be observed for any signs of infection, and if mastitis is known to be due to staphylococcal or streptococcal infection, simultaneous antibiotic treatment of the infant may be considered.

There is no evidence of risk to the healthy, term infant of continuing breastfeeding from a mother with mastitis. Women who are unable to continue breastfeeding should express the milk from breast by hand or pump, as sudden cessation of breastfeeding leads to a greater risk of abscess development than continuing to feed.

If there is no improvement after two days of antibiotic treatment or the infection keeps coming back, breast milk cultures can be taken to check the nature of the bacteria and identify the antibiotic sensitivity of the bacteria. MRSA is increasingly being identified in these cases and requires different antibiotics (ABM, 2014).

Mother holds newborn baby just after birth
Skin-to-skin contact with mother colonises baby with protective bacteria

MRSA and breastfeeding

There are different recommendations for MRSA and breastfeeding depending whether your baby is full term and healthy or premature/vulnerable. Advice also differs slightly between authors when the MRSA infection is on the breast—where a baby may have skin-to-skin contact with it—or somewhere else on the body.

If your baby is full term and healthy

By the time an MRSA infection is diagnosed, a baby will usually have already been exposed to it by being in close contact with his mother. As such, general advice is that if a mother has an MRSA infection, her healthy, full term baby can usually continue to breastfeed while his mother, or mother and baby (if necessary), receive treatment.4567

Canadian paediatrician and breastfeeding expert Dr Jack Newman explains;

First of all, mothers and babies share germs and if the mother gets mastitis, usually caused by Staphylococcus aureus, the baby has already been exposed to the infection, before the mother got mastitis. Bacteria don’t suddenly appear out of the blue and immediately cause infection. It takes time, at least a few days, and the whole time, the mother and the baby are sharing this germ. In fact, mothers have often been colonized with the bacteria for weeks or months even before the baby was born. Even if the bacterium causing the mastitis is MRSA (methicillin-resistant Staphylococcus aureus), this does not mean the mother should stop breastfeeding. The fact of the matter is that the immune protection a baby gets from breastfeeding is not theoretical, it’s real and taking the baby off the breast will only increase his chances of getting sick and more severely sick than if he remained breastfeeding, even on the side of the infected breast.

Any areas of skin with an MRSA infection should be kept covered so the baby doesn’t have any contact with them since MRSA is spread by direct contact. Careful hygiene is recommended to help prevent transmission such as washing hands before breastfeeding, and sterilising pump parts carefully.8

If a mother has a MRSA infection, can she continue to breastfeed?
Usually, yes. Continued breastfeeding is appropriate and recommended for most healthy infants. Breastfeeding promotes drainage and helps to resolve the infection, if it involves the breast. Staph bacteria, including MRSA, are not transmissible via human milk; however, these bacteria can be transferred through direct contact with infected tissue, such as an open lesion on the breast, or through expressed milk that has come in contact with infected tissue. Breastfeeding can continue on the affected breast (even if a drain is present in the case of an abscess) as long as the infant’s mouth does not come in contact with purulent drainage or open infected tissue.

Some authors recommend interrupting breastfeeding for 24-48 hours

In contrast to the above guidelines, some authors advise interrupting breastfeeding for 24 hours and pumping and dumping breast milk if there is an active MRSA infected sore on the breast, or if the mother has mastitis, an abscess, or surgical incision drainage involving MRSA.910 Others state that if the MRSA infection is close to one nipple or areola a mother can continue to breastfeed from the other breast while discarding the milk on the affected breast for the first 48 hours of antibiotic treatment.1112

Mothers should be guided by their health professionals for their particular situation. If there is any interruption in breastfeeding on either breast, a mother will need to pump during the interval to keep her milk supply going.

When the infection is systemic

The only information I have found mentioning breastfeeding when the mother has a systemic infection is from infantrisk.com:

if [the mother] has systemic symptoms such as fever and chills, she should begin her antibiotic regimen and wait 24 to 48 hours after beginning her antibiotic regimen before returning to breastfeeding. Once her systemic symptoms have resolved then she may restart breastfeeding.

If baby is poorly or premature

Babies who are premature, poorly, very low birth weight or in the neonatal unit are more vulnerable to becoming sick from MRSA. Particular risk factors include recent surgery, use of IV catheters, ventilation or a low immune system (MRSA Action UK, 2021). If a mother of a vulnerable baby has symptoms of an MRSA infection she may be advised to have her milk cultured to check for the presence of MRSA before breastfeeding or giving express milk (CDC, 2021) or asked to consider withholding breast milk until MRSA mastitis has cleared up (MRSA Action UK, 2021). Authors Lawrence and Lawrence explain:

When infants in NICUs (premature, LBW or VLBW, and/or previously ill) or their mothers have a MRSA infection, those infants should have the breast milk cultured and suspend breastfeeding or receiving breast milk from their mothers until the breast milk is shown to be culture-negative for MRSA. The infant should be treated as indicated for infection or empirically treated if symptomatic (with pending culture results) and closely observed for the development of new signs or symptoms of infection. Pumping to maintain the milk supply and the use of banked breast milk are appropriate.

Mohrbacher writes that if MRSA is cultured in breast milk, the milk could be pasteurised by heating to 62.5 C for 30 minutes (Holder pasteurisation) before feeding (Mohrbacher, 2020 p 816). Holder Pasteurization inactivates the vast majority of bacteria and viruses1314 If pasteurisation is not possible the expressed milk may need to be discarded for 24-48 hours after starting antibiotic treatment (CDC, 2021).

As stated above, careful hygiene such as hand washing and covering any open wounds is important to avoid spreading the infection.

Treatment for MRSA staph infection

Although MRSA is resistant to traditionally used antibiotics there are several medications compatible with breastfeeding that can be used to combat the infection.1516 It is important to let your health care team know if you have or have had MRSA before to help with treatment (MRSA Action UK, 2021).

Most strains of methicillin- resistant staphylococci are susceptible to vancomycin or trimethoprim/sulfamethoxazole but may not be susceptible to rifampin. Of note is that MRSA should be presumed to be resistant to treatment with macrolides and quinolones, regardless of susceptibility testing results.

Dr Newman discusses his preferred treatment:

Antibiotics that can be used for methicillin-resistant Staphylococcus aureus (MRSA): cotrimoxazole is the drug that Dr. Newman prefers as a first choice.  It contains two anti-infective medications and thus it is less likely the bacterium will be resistance and less likely to become resistant.

The compatibility of any medications with breastfeeding can be checked against one of the resources listed in Medications and Breastfeeding. Some breastfed babies may be sensitive to a particular antibiotic their mother takes. If your baby develops a rash or if there is a change in the baby’s stools, check with your doctor as you may need a different antibiotic (MRSA Action UK, 2021).

Avoiding MRSA infection

The transfer of MRSA infections can be minimised in a hospital birth setting by:

  • Encouraging a baby’s skin-to-skin contact with his mother as soon as possible after birth and frequently thereafter so that baby is colonised with protective friendly bacteria 17
  • Breastfeeding as soon as possible to promote the growth of protective bacteria in baby’s gut
  • Keeping baby with his mother, not in a newborn nursery
  • Avoiding skin-to-skin contact with hospital staff
  • Observing hygiene such as frequent hand washing

Summary

Breastfeeding can continue when a mother has a staphylococcus aureus bacterial infection. If a mother has a methicillin-resistant Staphylococcus aureus (MRSA) infection:

  • Breastfeeding can usually continue if the baby is healthy and full term while the mother (or mother and baby) receive antibiotic treatment for the MRSA infection. If an active MRSA infection is on the breast, advice varies between professionals. Some recommend continuing breastfeeding through treatment; because the baby will have already been exposed to the infection. Others recommend stopping breastfeeding for a day or two while the mother receives antibiotics; particularly from an affected breast if the wound is close to the nipple.
  • If a baby is poorly or premature, breastfeeding may need to be interrupted for 24-48 hours while a mother receives treatment or while the milk is cultured for the presence of MRSA. Parents will need to carefully consider their choice of replacement feed during any pause in breastfeeding, in particular the impact supplementing with formula could have on their baby’s immune system at a vulnerable time. Lawrence and Lawrence 18 advocate the use of banked breast milk if a substitute is needed.

Contact your health professional for advice for your situation. This article is not intended as a substitute for medical advice.