Breast infections following mastectomy and reconstruction in breast oncology patients.

Background: Many organisms have been implicated in post-operative SSIs following breast reconstruction. We report on the microbial species encountered after breast reconstructive surgery at a large tertiary care cancer center.

Methods: From Jan 1, 2013-Oct 30, 2015, patients with culture proven superficial or deep incisional SSIs based on NHSN criteria were identified through the infection control surveillance system and categorized by procedure code (CPT code). Preoperative bathing with chlorhexidine and pre-op cefazolin (clindamycin vs fluoroquinolone in PCN allergic patients) are standard of care. Patient demographic information, reconstruction characteristics, microbiological data and postsurgical antibiotic prophylaxis were reviewed (Table 1). Epidemiologically related infections due to the same species were molecularly characterized to evaluate common source infections.

Results: During the 22 month study period, 2340 patients underwent surgery, 69 (2.95%) developed culture proven SSI. All the patients were female. Overall infection rates in biologic vs prosthetic reconstruction were not significantly different (29 vs 21 per 1000 procedures). Gram-positives (MSSA, 44.9%; MRSA 11.6%) were most common. Among gram negatives, PSAE was the dominant organism. CONS although common was mostly found in polymicrobial culture. The majority of monomicrobial infections were caused by MSSA. No common sources were identified by PFGE characterization of temporally related MRSA and PSAE isolates.

Conclusion: The rate of culture proven infection among our cohort of over 2300 patents was 2.95%. Gram-positive organisms accounted for the majority of SSIs following breast reconstructive surgery. Among gram negatives, Pseudomonas was the most common organism. Genotyping of organisms from temporally related infections identified sporadic strains without evidence of clonal spread.

Table 1.

Age
	Median	49	(range 28-84)
Laterality
	Left	16	23.2%
	Right	17	24.6%
	Bilateral	39	52.2%
Types of Reconstruction
	Biologic	13	18.8%
	Prosthetic	56	81.2%
Organism
	CONS
	MRSA
	MSSA
	MYCO
	PSAE
Post-procedure Antibiotic Prophylaxis
	Cephalosporin	51	73.9%
	Clindamycin	6	8.7%
	Levofloxacin	7	10.1%
	None specified	5	7.2%

Cephalosporin Clindamycin Levofloxacin None specified