Re-Infection after Explantation of Infected Hernia Mesh: Are the Same Micro-Organisms Involved?

It is unclear if a history of mesh explantation for infection is predictive of future microbiology after subsequent hernia operations. We investigated how often the same causative organism is cultured in the initial explantation and subsequent repairs. We obtained data on patients undergoing ventral/incisional, umbilical, and inguinal hernia repairs from the Veterans Affairs Surgical Quality Improvement Program during 2008-2015. Manual review was performed for all patients with an administrative code indicative of mesh explantation and those with explantation for infection were retained. We then obtained data on cultured organisms from the mesh site at the time of index explantation and at any re-repair or subsequent explantation during a follow-up period ending in December 2020. We identified 332 patients undergoing mesh explantation because of infection (64.8% ventral, 18.7% umbilical, 16.6% inguinal). Mean age was 60.3 years (standard deviation [SD], 9.7) and 93.9% were male. The same organism was cultured at re-infection in 23 of 59 (39%) cases. Gram-positive micro-organisms were the most prevalent in 20 of 23 (87%). Among the gram-positive, Staphylococcus aureus was the most common pathogen and was cultured in 18 of 20 (90%) cases, of which 14 of 18 (77.8%) were methicillin-susceptible Staphylococcus aureus (MSSA) and 4 of 18 (22.2%) were methicillin-resistant Staphylococcus aureus (MRSA). Three of 23 (13%) gram-negative organisms were the same at both re-infection and index explantation consisting of Escherichia coli in 2 of 3 (66.7%), and Pseudomonas aeruginosa in one of three (33.3%). Identification of organisms at time of prosthetic infection is helpful not only in treating the initial infection, but also in prevention of infection with the same organisms after subsequent repairs. Same organism re-infection should not be underestimated, particularly when Staphylococcus aureus is isolated.