Mycobacterium fortuitum: A Rare Cause of Surgical Site Infection.

Mycobacterium fortuitum is a rapidly growing nontuberculous mycobacterium mainly associated with skin, soft tissue and surgical site infections. We report an unusual outbreak of 6 cases of surgical site infection following spinal surgery. Patients received combined intravenous antibiotics, including amikacin, followed by an extended period of oral therapy with favorable clinical outcomes. No instrumentation replacement was performed in any case.

Impact of antibiotic prophylaxis in second-stage surgery in joint prosthesis infection treated with two-stage exchange. A multicenter case-control study.

INTRODUCTION: After two-stage exchange due to prosthetic joint infection (PJI), the new prosthesis carries a high risk of reinfection (RePJI). There isn`t solid evidence regarding the antibiotic prophylaxis in 2nd-stage surgery. The objective of this study is to describe what antibiotic prophylaxis is used in this surgery and evaluate its impact on the risk of developing RePJI. METHODS: Retrospective multicenter case-control study in Spanish hospitals. The study included cases of PJI treated with two-stage exchange and subsequently developed a new infection. For each case, two controls were included, matched by prosthesis location, center, and year of surgery. The prophylaxis regimens were grouped based on their antibacterial spectrum, and we calculated the association between the type of regimen and the development of RePJI using conditional logistic regression, adjusted for possible confounding factors. RESULTS: We included 90 cases from 12 centers, which were compared with 172 controls. The most frequent causative microorganism was Staphylococcus epidermidis with 34 cases (37.8%). Staphylococci were responsible for 50 cases (55.6%), 32 of them (64%) methicillin-resistant. Gram-negative bacilli were involved in 30 cases (33.3%), the most common Pseudomonas aeruginosa. In total, 83 different antibiotic prophylaxis regimens were used in 2nd-stage surgery, the most frequent a single preoperative dose of cefazolin (48 occasions; 18.3%); however, it was most common a combination of a glycopeptide and a beta-lactam with activity against Pseudomonas spp (99 cases, 25.2%). In the adjusted analysis, regimens that included antibiotics with activity against methicillin-resistant staphylococci AND Pseudomonas spp were associated with a significantly lower risk of RePJI (adjusted OR = 0.24; 95% IC: 0.09-0.65). CONCLUSIONS: The lack of standardization in 2nd-satge surgery prophylaxis explains the wide diversity of regimens used in this procedure. The results suggest that antibiotic prophylaxis in this surgery should include an antibiotic with activity against methicillin-resistant staphylococci and Pseudomonas.

Description of reinfection of joint prosthesis after 2-stage replacement (infection of the 2nd stage prosthesis): A multicenter study.

INTRODUCTION: Two-stage exchange is the gold standard in the surgical management of prosthetic joint infection (PJI). However, perioperative reinfections (RePJI) can occur to newly inserted prosthesis, which highlights the importance of an adequate antibiotic prophylaxis, although there is scarce evidence in this field. Our objective was to evaluate the characteristics of RePJI, its prognosis and the antibiotic prophylaxis that is commonly used in second-stage surgery. METHODS: Multicentric retrospective observational study in Spanish hospitals including patients with RePJI between 2009 and 2018. RESULTS: We included 92 patients with RePJI from 12 hospitals. The most frequent isolated microorganism was Staphylococcus epidermidis in 35 cases (38.5%); 61.1% of staphylococci were methiciliin-resistant. In 12 cases (13%), the same microoganism causing the primary PJI was isolated in RePJI. When comparing with the microbiology of primary PJI, there were more cases caused by Gram-negative bacteria (the most frequent was Pseudomonas spp.) and less by Gram-positive bacteria. Failure occured in 69 cases (75%). There were 43 different courses of antibiotic prophylaxis after the second-stage surgery; the most frequent was a unique preoperative cefazolin dose, but most patients received prophylaxis before and after the second-stage surgery (61 cases). CONCLUSIONS: The most frequent microorganisms in RePJI are coagulase-negative staphylococci, although Gram-negative bacteria, especially Pseudomonas spp. are also common. There is a significant heterogeneity in antibiotic prophylaxis for a second-stage surgery. ReIPJI treatment has a high failure rate.

Prognosis of unexpected positive intraoperative cultures in arthroplasty revision: A large multicenter cohort.

BACKGROUND: The positive-intraoperative-cultures-type prosthetic joint infection (PIOC-PJI) is considered when surgical cultures yield microorganisms in presumed aseptic arthroplasty revisions. Herein we assess the risk factors for failure in the largest cohort of PIOC-PJI patients reported to date. METHODS: A retrospective, observational, multicenter study was performed during 2007-2017. Surgeries leading to diagnose PIOC-PJI included only one-stage procedures with either complete or partial prosthesis revision. Failure was defined as recurrence caused by the same microorganism. RESULTS: 203 cases were included (age 72 years, 52% females). Coagulase-negative staphylococci (n = 125, 62%) was the main etiology, but some episodes were caused by virulent bacteria (n = 51, 25%). Prosthesis complete and partial revision was performed in 93 (46%) and 110 (54%) cases, respectively. After a median of 3.4 years, failure occurred in 17 episodes (8.4%, 95%CI 5.3-13.1). Partial revision was an independent predictor of failure (HR 3.63; 95%CI 1.03-12.8), adjusted for gram-negative bacilli (GNB) infection (HR 2.68; 95%CI 0.91-7.89) and chronic renal impairment (HR 2.40; 95%CI 0.90-6.44). Treatment with biofilm-active antibiotics (rifampin/fluoroquinolones) had a favorable impact on infections caused by staphylococci and GNB. CONCLUSION: Overall prognosis of PIOC-PJI is good, but close follow-up is required in cases of partial revision and in infections caused by GNB.