Cultures for Infected Breast Implant
For an infected breast implant, send at least 3-5 deep tissue samples (not swabs) for both aerobic and anaerobic bacterial cultures, plus fungal cultures, obtained intraoperatively from periprosthetic tissue and fluid surrounding the implant. 1, 2
Specimen Collection Technique
Obtain multiple tissue samples (minimum 3, optimally 5-6 separate specimens) from different sites around the implant and adjacent tissue using separate sterile instruments for each sample to maximize diagnostic yield 1
Collect tissue specimens, not swabs, as swabs have low sensitivity and high contamination risk; tissue samples should be homogenized for optimal culture results 1, 3
Submit adequate volume: at least 1 mL of fluid or 0.5 g of tissue per specimen, with larger volumes increasing pathogen recovery 1
Inoculate specimens directly into blood culture bottles (1-10 mL of fluid into aerobic bottles, and if anaerobic cultures requested, into anaerobic bottles as well) for greatest accuracy 1, 4
Culture Types to Order
Aerobic bacterial cultures are essential, as methicillin-resistant staphylococci (44%) and gram-negative pathogens (26%) including Pseudomonas (13%) are the most common causative organisms 2, 5
Anaerobic bacterial cultures should be obtained, as anaerobic bacteria including Propionibacterium acnes, Peptostreptococcus, and other anaerobes are identified in breast implant infections and require specific transport media 1, 3, 4
Fungal cultures must be sent in appropriate transport medium to a laboratory with mycology expertise, as Candida species can cause breast implant infections, particularly multidrug-resistant strains 2, 6, 3
Timing and Antibiotic Considerations
Withhold antibiotics for at least 2 weeks prior to culture collection when medically safe to do so, as this significantly increases the yield of organism recovery 1
If the patient is unstable or antibiotics cannot be safely withheld, obtain cultures immediately after sampling and before administering new antibiotics 1
Microbiologic Interpretation
Two or more cultures yielding the same organism (identical genus, species, and antibiogram) is considered definitive evidence of prosthetic infection 1
Single culture growing highly virulent organisms (S. aureus, E. coli, Pseudomonas) should raise high suspicion for true infection even without confirmatory cultures 1, 5
Single culture with common contaminants (coagulase-negative staphylococci, P. acnes) should be interpreted cautiously in clinical context and not automatically considered definitive infection 1
Request susceptibility testing for all Staphylococcus aureus, Pseudomonas, and predominant Enterobacteriaceae isolates, as these are more likely to harbor resistance 1
Common Pitfalls
Avoid culturing sinus tracts if present, as these are commonly contaminated with commensal skin flora and do not accurately reflect the causative pathogen 1
Do not rely on blood cultures alone, as they provide limited additional information for localized implant infections unless systemic signs are present 1
Regional variation exists: Local microbiome patterns differ significantly by geographic location and institution, so empiric therapy should be guided by your institution's specific resistance patterns 5, 3, 4
The microbiology of breast implant infections shows increasing proportions of gram-negative bacteria (particularly Pseudomonas aeruginosa as the second most common pathogen in some series) and anaerobic bacteria, emphasizing the importance of comprehensive culture techniques 5, 3