Mastitis is an infection of the breast. It usually only occurs in women who are breastfeeding their babies.
Breastfeeding is the act of allowing a baby to suckle at the breast to drink the mother’s milk. In the process, unaccustomed to the vigorous pull and tug of the infant’s suck, the nipples may become sore, cracked, or irritated. This creates a tiny opening in the breast, through which bacteria can enter. The presence of milk, with high sugar content, gives the bacteria an excellent source of nutrition. Under these conditions, the bacteria are able to multiply, until they are plentiful enough to cause an infection within the breast.
Mastitis usually begins more than two to four weeks after delivery of the baby. It is a relatively uncommon complication of breastfeeding mothers, occurring in only approximately 3% to 5% of nursing women.
Causes and symptoms
The most common bacteria causing mastitis is called Staphylococcus aureus. In 25-30% of people, this bacteria is present on the skin lining normal, uninfected nostrils. It is probably this bacteria, clinging to the baby’s nostrils, that is available to create infection when an opportunity (crack in the nipple) presents itself.
Usually, only one breast is involved. An area of the affected breast becomes swollen, red, hard, and painful. Other symptoms of mastitis include fever, chills, and increased heart rate.
Diagnosis involves obtaining a sample of breast milk from the infected breast. The milk is cultured, allowing colonies of bacteria to grow. The causative bacteria then can be specially prepared for identification under a microscope. At the same time, tests can be performed to determine what type of antibiotic would be most effective against that particular bacteria. Sometimes, women and their physicians confuse mastitis with breast engorgement, or the tenderness and redness that appears when milk builds up in the breasts. Mastitis often can be distinguished if symptoms are accompanied by fever.
A number of antibiotics are used to treat mastitis, including cephalexin, amoxicillin, azithromycin, dicloxacillin, and clindamycin. Breastfeeding usually should be continued, because the rate of abscess formation (an abscess is a persistent pocket of pus) in the infected breast goes up steeply among women who stop breastfeeding during a bout with mastitis. Most practitioners allow women to take acetaminophen while nursing, to relieve both fever and pain. As always, breastfeeding women need to make sure that any medication they take is also safe for the baby, since almost all drugs they take appear in the breastmilk. Warm compresses applied to the affected breast can be soothing.
Prognosis for uncomplicated mastitis is excellent. About 10% of women with mastitis will end up with an abscess within the affected breast. An abscess is a collection of pus within the breast. This complication will require a surgical procedure to drain the pus.
The most important aspect of prevention involves good handwashing to try to prevent the infant from acquiring the Staphylococcus aureus bacteria in the first place. Keeping the breast clean before breastfeeding also helps prevent infection. Keeping the breasts from becoming engorged may help prevent mastitis by preventing plugging of milk ducts.
Types Of Mastitis
acute swelling of the mammary gland accompanied by heat and pain, together with grossly abnormal milk. There may be a slight systemic reaction.
severe, usually peracute clinical mastitis in which one or more quarters become gangrenous. Usually caused by Staphylococcus aureus.
persistent local infection, usually by Staphylococcus aureus, causes granulomas and the collection of pus within them to produce a botryomycotic effect. See also coliform mastitis.
caused by Escherichia coli, Klebsiella spp. or Enterobacter aerogenes. See coliform mastitis.
caused by those bacteria which are resident in bovine udders or on teat skin and are spread primarily during milking. Staphylococcus aureus,Streptococcus agalactiae, S. dysgalactiae are the common causes. Called also ‘cow-associated’ mastitis.
aimed at reducing new infection rate and the static quarter infection rate; based on dry period treatment, culling or treating infected animals, teat disinfection, teat cup liner sanitization, and milking machine maintenance and correct use.
discarding mastitis milk
milk from infected quarters flushed to waste, not fed to calves.
mastitis dry cow treatment
intramammary infusion with a long-acting formulation, at the time of the last milking for the lactation; may be blanket (all cows) or selective (infected quarters only). See also dry period treatment.
caused by those bacteria which are usually resident in the environment of the cow, especially in the feces, bedding or water. Escherichia coli,Streptococcus uberis are the common infections. See also coliform mastitis.
the teat and much of the quarter are black and cold, the secretion is thin blood-stained fluid and there is a severe systemic reaction. The quarter is lost, and the cow may very well die.
see botryomycotic mastitis (above).
mastitis infection rate
rate of quarters or cows infected with pathogenic bacteria or showing clinical mastitis or, a much more commonly used index nowadays, the percentage of cows with a milk cell count in excess of a stated norm.
NIRD mastitis control program
the basis of all modern mastitis control programs. Named after the National Institute for Research in Dairying (now called the Animal Grassland Research Institute) at Reading, UK, which introduced dry period treatment and teat dipping into mastitis control. Highly effective in reducing the prevalence of contagious mastitis pathogens such as Streptococcus agalactiae, Staphylococcus aureus. Called also ‘five point program’.
as for acute mastitis, but there is also a severe systemic reaction and the cow may die of the attending septicemia.
a chronic disease in cattle caused by Nocardia asteroides, also occurs in sows caused by Actinomyces suis.
testing for evidence of inflammation of mammary epithelium, of individual cows or entire herd, by use of milk cell counts, biochemical tests which measure products of inflammation, e.g. NAG-ase test, electrical conductivity.
mastitis in which the only evidence of disease is an abnormality of cell count or other clinicopathological parameter.
a serious disease likely to cause the loss of the quarter and a severe clinical illness. Caused by Arcanobacterium pyogenes and other unspecified cocci. See also Table 16.
mastitis in which the secretion of the quarter is largely pus.
mastitis in which the infection is introduced through the skin into the teat canal or mammary tissue by a penetrating injury; it is usually a mixed infection and causes a suppurative or gangrenous mastitis, depending on the bacteria that are present. The quarter is ruined and the cow may die. See also Table 16.
mastitis treatment withholding times
after intramammary infusion in lactating cow—withhold 72 hours; dry cow intramammary infusion—administered at least 4 weeks before calving, withhold for 96 hours after calving.
not proven to exert beneficial effect. Only vaccination with an autogenous bacterin against Staphylococcus aureus, where the infecting organism is highly antigenic, appears to even reduce the severity of the disease.