Medication Summary
The goals of pharmacotherapy are to reduce morbidity, prevent complications and eradicate the infection.
Empiric therapy should have activity against S aureus, a common pathogen of primary breast abscess. Other pathogens may include methicillin-resistant S aureus (MRSA), Streptococcus pyogenes, E coli, Bacteroides species, Corynebacterium species, coagulase-negative staphylococci, Pseudomonasaeruginosa, Proteusmirabilis, and anaerobes. Therapy should be tailored to results of cultures and susceptibilities, if applicable.
Recurrent breast abscesses have an increased risk for mixed flora and anaerobic pathogens.
Antibiotics should be continued for 10 to 14 days.
Outpatient therapy for non-severe infection without MRSA risk: dicloxacillin or cephalexin or amoxicillin-clavulanate
Outpatient therapy in patients with hypersensitivity to beta-lactams: clarithromycin or doxycycline
Outpatient therapy for non-severe infection with MRSA risk: trimethoprim-sulfamethoxazole or clindamycin. Trimethoprim-sulfamethoxazole may be associated with an increased risk of allergic reactions relative to other MRSA-directed therapies. [100, 101]
Inpatient therapy for severe infection without risk of MRSA: nafcillin or oxacillin or ampicillin-sulbactam
Inpatient therapy for severe infection with risk of MRSA or in patients with beta-lactam allergy: clindamycin or vancomycin or linezolid or tigecycline or daptomycin
Emerging therapies include ceftaroline or dalbavancin or delafloxacin or oritavancin. These drugs have been approved by the FDA for treatment of soft-tissue infections but have not yet been studied specifically for treating breast infections.
Antibiotics
Class Summary
Antibacterial therapy must cover all likely pathogens in the context of the clinical setting.
Penicillins
Dicloxacillin
Outpatient therapy
Drug of choice (DOC) for mastitis. Bactericidal antibiotic that inhibits cell wall synthesis. Used to treat infections caused by penicillinase-producing staphylococci. May be used to initiate therapy when a staphylococcal infection is suspected.
Amoxicillin/clavulanate (Augmentin, Augmentin ES-600, Augmentin XR)
Outpatient therapy
Amoxicillin binds to penicillin-binding proteins, thus inhibiting final transpeptidation step of peptidoglycan synthesis in bacterial cell walls; addition of clavulanate inhibits beta-lactamase–producing bacteria, allowing amoxicillin extended spectrum of action
It is a semisynthetic antibiotic with a broad spectrum of bactericidal activity, covering both gram-negative and gram-positive microorganisms.
Nafcillin
Inpatient therapy
DOC for puerperal breast abscess. Used to treat infections caused by penicillinase-producing staphylococci. Used to initiate therapy when a penicillin G–resistant staphylococcal infection is suspected.
Because of occasional occurrence of thrombophlebitis associated with parenteral route (particularly in elderly persons), administer parenterally only for a short term (24-48 hours) and change to a PO equivalent, if clinically possible.
Oxacillin (Bactocill)
Inpatient therapy
Bactericidal antibiotic that inhibits cell wall synthesis. Used in the treatment of infections caused by penicillinase-producing staphylococci. May be used to initiate therapy when a staphylococcal infection is suspected.
Ampicillin/sulbactam (Unasyn)
Inpatient therapy
Alternative DOC for nonpuerperal breast abscess. Drug combination that utilizes a beta-lactamase inhibitor with ampicillin.
Covers skin, enteric flora, and anaerobes. Not ideal for nosocomial pathogens.
Cephalosporins, 1st Generation
Cephalexin (Keflex, Daxbia)
Outpatient therapy
Cephalexin is a first-generation cephalosporin that binds to penicillin-binding proteins, therefore inhibiting bacterial cell wall synthesis. May be used to initiate therapy when a staphylococcal infection is suspected. Lacks coverage of gram-negative pathogens.
Cephalosporins, 4th Generation
Ceftaroline (Teflaro)
Emerging therapy
Beta-lactam cephalosporin with activity against aerobic and anaerobic gram-positive and aerobic gram-negative bacteria.
Demonstrates activity in vivo against resistant MRSA strains and in vitro against vancomycin-resistant and linezolid-resistant S aureus.
Pregnancy Category B, effects unknown. Unknown if secreted in breast milk; use caution if breastfeeding.
Fluoroquinolones
Delafloxacin (Baxdela)
Emerging treatment
Fluoroquinolone antibiotic that inhibits enzymes required for bacterial synthesis.
In vitro activity against S aureus (including MRSA), Streptococcus species, E coli, K pneumoniae, E cloacae, and P aeruginosa.
Limited data regarding use in pregnancy and lactation.
Glycopeptides
Vancomycin
Inpatient treatment
DOC for patients with puerperal breast abscess who are penicillin-allergic, as well as those with suspected MRSA infection. It is a potent antibiotic directed against gram-positive organisms and active against enterococcal species. Useful in treatment of septicemia and skin structure infections. Indicated for patients who cannot receive or have failed to respond to penicillins and cephalosporins or who have infections with resistant staphylococci.
To avoid toxicity, current recommendation is to assay vancomycin trough levels after the third dose drawn 0.5 hour before next dosing. Use CrCl to adjust dose in renal impairment, prn.
Caution: Vancomycin can cross the placenta and into breast milk. Use caution in pregnant and breastfeeding mothers.
Dalbavancin (Dalvance)
Emerging treatment
Lipoglycopeptide antibiotic; interferes with cell wall synthesis by binding to D-alanyl-D-alanine terminus of the stem pentapeptide in nascent cell wall peptidoglycan, thus preventing crosslinking.
Bactericidal in vitro against S aureus and S pyogenes at concentrations observed in humans at recommended doses.
Caution: Pregnancy category C, the long half-life of dalbavancin should be considered before using in pregnancy. Unknown if secreted in breast milk.
Oritavancin (Orbactiv)
Emerging treatment
Lipoglycopeptide antibiotic; interferes with bacteria cell wall synthesis by inhibiting transglycosidation and transpeptidation. Also disrupts the integrity of bacterial membranes, leading to cell death.
Exhibits concentration-dependent bactericidal activity against S aureus (including MRSA), Streptococcus species, and Enterococcus faecalis (not VRE).
Caution: Pregnancy category C. Unknown if distributed in human breast milk.
Glycylcyclines
Tigecycline (Tygacil)
Inpatient treatment
If MRSA risk with beta-lactam allergy.
A glycylcycline antibiotic that is structurally similar to tetracycline antibiotics; inhibits bacterial protein translation by binding to 30S ribosomal subunit and blocks entry of aminoacyl tRNA molecules in ribosome A site.
Caution: Pregnancy Category D. Unknown, but suspected to be secreted in breast milk; do not use in pregnancy or if breastfeeding.
Oxazolidinones
Linezolid (Zyvox)
Inpatient or outpatient treatment
If MRSA risk with beta-lactam allergy.
Binds to bacterial 23S rRNA of the 50S subunit to prevent protein translation; also elicits nonselective MAO inhibition.
Caution: Pregnancy category C; secreted in breast milk, use caution if used while breastfeeding.
Lincosamide
Clindamycin (Cleocin)
Outpatient or inpatient therapy
Clindamycin is a semisynthetic antibiotic produced by 7(S)-chloro-substitution of the 7(R)-hydroxyl group of the parent compound, lincomycin. It inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Clindamycin is widely distributed in the body without penetrating the central nervous system (CNS). It is protein-bound and excreted by the liver and kidneys.
Lipopeptides
Daptomycin (Cubicin)
Inpatient treatment
If MRSA risk with beta-lactam allergy.
Cyclic lipopeptide: Binds to bacterial membranes and causes rapid depolarization of membrane potential; causes inhibition of protein, DNA, RNA synthesis, and bacterial cell death.
Pregnancy category B, successful use during second and third trimesters of pregnancy reported but limited information available. Secreted in breast milk in low concentrations, however, it is poorly bioavailable orally; use caution if breastfeeding.
Sulfonamides
Trimethoprim/sulfamethoxazole (Bactrim, Bactrim DS)
Outpatient therapy
For non-severe MRSA infections.
Trimethoprim: Inhibits dihydrofolate reductase, thereby blocking production of tetrahydrofolic acid from dihydrofolic acid.
Sulfamethoxazole: Inhibits bacterial synthesis of dihydrofolic acid by competing with paraaminobenzoic acid.
Caution: Pregnancy category D. Medication crosses into breast milk. Avoid use in breastfeeding mother if nursing preterm infants, infants <2 months, or children with known or suspected glucose-6-phosphate dehydrogenase (G6PD) deficiency.
Tetracyclines
Doxycycline (Acticlate, Adoxa, Doryx, Morgidox, Vibramycin)
Outpatient or inpatient therapy
If beta-lactam hypersensitivity.
Doxycycline is a tetracycline. Inhibits protein synthesis and, thus, bacterial growth by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria; may block dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest.
Caution: Pregnancy Category D and secreted in breast milk; do not use in pregnancy or if breastfeeding.
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Ultrasonogram demonstrates a hypoechoic mass with smooth, partially lobulated margins typical of a fibroadenoma.
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Craniocaudal mammograms obtained 1 year apart demonstrate a newly developing mass in the outer part of the breast.
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Spot compression mammogram of the outer part of the breast demonstrates a new mass as smooth, margined, and oval. The findings are consistent with a fibroadenoma, a cyst, or a malignancy. In this patient, the diagnosis was a rapidly growing fibroadenoma.
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Eggshell or rim calcifications (arrows) have walls thinner than those of lucent-centered calcifications.
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This mass with associated large, coarse calcifications (arrows) is a degenerating fibroadenoma.
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Breast cancer, ultrasonography. Mediolateral oblique digital mammogram of the right breast in a 66-year-old woman with a new, opaque, irregular mass approximately 1 cm in diameter. The mass has spiculated margins in the middle third of the right breast at the 10-o'clock position. Image demonstrates both the spiculated mass (black arrow) and separate anterior focal asymmetry (white arrow).
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Breast cancer, ultrasonography. Antiradial sonogram of the spiculated mass (shown in the image above) demonstrates a hypoechoic mass with angular margins (black arrows). Cursors on the margins of the mass were used to electronically measure its dimensions of the mass, which was 0.9 X 0.8 cm.
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Breast cyst. A) A simple, fairly round breast cyst with hypo or anechoic contents and well-defined borders; B) Posterior acoustic enhancement is seen as well as edge shadows (arrows).
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Breast adenoma. A) A breast adenoma is oval with well-defined borders. It may be hypoechoic and some internal echogenicity may be seen. It is wider than tall and posterior acoustic enhancement is NOT seen, helping distinguish from a cyst or other fluid collection. B) An arrow indicates the adenoma.
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Breast hematoma. A) A breast hematoma is seen as a round echogenic collection with surrounding tissue edema. A hematoma may be hypoechoic, mixed, or fairly echogenic depending on the stage of the hematoma. B) The hematoma is outlined and tissue edema noted.
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Loculated breast abscess. A) A large loculated abscess is seen containing hypoechoic fluid and some internal echoes. Posterior acoustic enhancement is seen. Care must be taken to image at an adequate depth to visualize posterior borders of breast lesions. B) The abscess is outlined in yellow and the posterior acoustic enhancement is noted.
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Loculated breast abscess, curvilinear. A) This is the same abscess seen in the above image and is imaged with a curvilinear transducer to better appreciate the extent of the abscess. It is important to image the abscess completely for width and depth. B) The abscess is outlined in yellow and the ribs and posterior acoustic enhancement are noted.
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Purulent breast abscess. A) A purulent breast abscess is seen. The fluid is echogenic, but can be recognized as a disruption of the surrounding tissue and posterior acoustic enhancement. B) The abscess is outlined in yellow and the posterior acoustic enhancement is noted.
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Complex breast abscess. In this clip, the features of a loculated breast abscess containing echogenic purulent material are noted. Example of imaging with a linear high-frequency transducer.
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Loculated breast abscess, curvilinear. In this clip, a large, loculated breast abscess and its features are noted. Example of imaging with a lower-frequency curvilinear transducer to better appreciate the extent of this large abscess.
