TY - JOUR
T1 - Staphylococcus aureus Breast Implant Infection Isolates Display Recalcitrance To Antibiotic Pocket Irrigants
AU - Duran Ramirez, Jesus M.
AU - Gomez, Jana
AU - Hanson, Blake M.
AU - Isa, Taha
AU - Myckatyn, Terence M.
AU - Walker, Jennifer N.
N1 - Funding Information:
The research reported in this publication was supported by an investigator-initiated award funded by the Plastic Surgery Foundation (to J.N.W. and T.M.M.) and by funds from the University of Texas Health Science Center at Houston (to J.N.W.).
Publisher Copyright:
Copyright © 2022 Duran Ramirez et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.
PY - 2023/1
Y1 - 2023/1
N2 - Breast implant-associated infections (BIAIs) are the primary complication following placement of breast prostheses in breast cancer reconstruction. Given the prevalence of breast cancer, reconstructive failure due to infection results in significant patient distress and health care expenditures. Thus, effective BIAI prevention strategies are urgently needed. This study tests the efficacy of one infection prevention strategy: the use of a triple antibiotic pocket irrigant (TAPI) against Staphylococcus aureus, the most common cause of BIAIs. TAPI, which consists of 50,000 U bacitracin, 1 g cefazolin, and 80 mg gentamicin diluted in 500 mL of saline, is used to irrigate the breast implant pocket during surgery. We used in vitro and in vivo assays to test the efficacy of each antibiotic in TAPI, as well as TAPI at the concentration used during surgery. We found that planktonically grown S. aureus BIAI isolates displayed susceptibility to gentamicin, cefazolin, and TAPI. However, TAPI treatment enhanced biofilm formation of BIAI strains. Furthermore, we compared TAPI treatment of a S. aureus reference strain (JE2) to a BIAI isolate (117) in a mouse BIAI model. TAPI significantly reduced infection of JE2 at 1 and 7 days postinfection (dpi). In contrast, BIAI strain 117 displayed high bacterial burdens in tissues and implants, which persisted to 14 dpi despite TAPI treatment. Lastly, we demonstrated that TAPI was effective against Pseudomonas aeruginosa reference (PAO1) and BIAI strains in vitro and in vivo. Together, these data suggest that S. aureus BIAI strains employ unique mechanisms to resist antibiotic prophylaxis treatment and promote chronic infection. IMPORTANCE The incidence of breast implant associated infections (BIAIs) following reconstructive surgery postmastectomy remains high, despite the use of prophylactic antibiotic strategies. Thus, surgeons have begun using additional antibiotic-based prevention strategies, including triple antibiotic pocket irrigants (TAPIs). However, these strategies fail to reduce BIAI rates for these patients. To understand why these therapies fail, we assessed the antimicrobial resistance patterns of Staphylococcus aureus strains, the most common cause of BIAI, to the antibiotics in TAPI (bacitracin, cefazolin, and gentamicin). We found that while clinically relevant BIAI isolates were more susceptible to the individual antibiotics compared to a reference strain, TAPI was effective at killing all the strains in vitro. However, in a mouse model, the BIAI isolates displayed recalcitrance to TAPI, which contrasted with the reference strain, which was susceptible. These data suggest that strains causing BIAI may encode specific recalcitrance mechanisms not present within reference strains.
AB - Breast implant-associated infections (BIAIs) are the primary complication following placement of breast prostheses in breast cancer reconstruction. Given the prevalence of breast cancer, reconstructive failure due to infection results in significant patient distress and health care expenditures. Thus, effective BIAI prevention strategies are urgently needed. This study tests the efficacy of one infection prevention strategy: the use of a triple antibiotic pocket irrigant (TAPI) against Staphylococcus aureus, the most common cause of BIAIs. TAPI, which consists of 50,000 U bacitracin, 1 g cefazolin, and 80 mg gentamicin diluted in 500 mL of saline, is used to irrigate the breast implant pocket during surgery. We used in vitro and in vivo assays to test the efficacy of each antibiotic in TAPI, as well as TAPI at the concentration used during surgery. We found that planktonically grown S. aureus BIAI isolates displayed susceptibility to gentamicin, cefazolin, and TAPI. However, TAPI treatment enhanced biofilm formation of BIAI strains. Furthermore, we compared TAPI treatment of a S. aureus reference strain (JE2) to a BIAI isolate (117) in a mouse BIAI model. TAPI significantly reduced infection of JE2 at 1 and 7 days postinfection (dpi). In contrast, BIAI strain 117 displayed high bacterial burdens in tissues and implants, which persisted to 14 dpi despite TAPI treatment. Lastly, we demonstrated that TAPI was effective against Pseudomonas aeruginosa reference (PAO1) and BIAI strains in vitro and in vivo. Together, these data suggest that S. aureus BIAI strains employ unique mechanisms to resist antibiotic prophylaxis treatment and promote chronic infection. IMPORTANCE The incidence of breast implant associated infections (BIAIs) following reconstructive surgery postmastectomy remains high, despite the use of prophylactic antibiotic strategies. Thus, surgeons have begun using additional antibiotic-based prevention strategies, including triple antibiotic pocket irrigants (TAPIs). However, these strategies fail to reduce BIAI rates for these patients. To understand why these therapies fail, we assessed the antimicrobial resistance patterns of Staphylococcus aureus strains, the most common cause of BIAI, to the antibiotics in TAPI (bacitracin, cefazolin, and gentamicin). We found that while clinically relevant BIAI isolates were more susceptible to the individual antibiotics compared to a reference strain, TAPI was effective at killing all the strains in vitro. However, in a mouse model, the BIAI isolates displayed recalcitrance to TAPI, which contrasted with the reference strain, which was susceptible. These data suggest that strains causing BIAI may encode specific recalcitrance mechanisms not present within reference strains.
KW - antibiotic resistance
KW - breast implant infections
KW - Pseudomonas aeruginosa
KW - Staphylococcus aureus
KW - triple antibiotic pocket irrigant
UR - http://www.scopus.com/inward/record.url?scp=85148114165&partnerID=8YFLogxK
U2 - 10.1128/spectrum.02884-22
DO - 10.1128/spectrum.02884-22
M3 - Article
C2 - 36507629
AN - SCOPUS:85148114165
SN - 2165-0497
VL - 11
JO - Microbiology spectrum
JF - Microbiology spectrum
IS - 1
ER -