Letter: Systemic Antimicrobial Prophylaxis and Antimicrobial-Coated External Ventricular Drain Catheters for Preventing Ventriculostomy-Related Infections: A Meta-Analysis of 5242 Cases

To the Editor: We read with interest the article "Systemic antimicrobial prophylaxis and antimicrobial-coated external ventricular drain catheters for preventing ventriculostomy-related infections: a meta-analysis of 5242 cases".1 The authors were able to find 19 studies to include in a meta-analysis out of over 600 articles, and accumulate over 5000 cases to analyze on the important topic of prophylactic antibiotic use for the prevention of ventriculostomy-related infection (VRI) in external ventricular drain placement. We were surprised that this meta-analysis concluded that extended courses of systemic prophylactic antibiotics were protective against VRIs given the growing literature supporting that prolonged surgical antibiotic prophylaxis courses are not protective for surgical site infections (SSIs) compared to perioperative doses alone.2-6 In Sheppard et al,1 Figure 1 part A suggests that the main driver of the meta-analysis' findings purporting prolonged antibiotics as protective from SSIs was a study in 2015 by Murphy et al2 entitled "No additional protection against ventriculitis with prolonged systemic antibiotic prophylaxis for patients treated with antibiotic-coated external ventricular drains". Upon review of the referenced article, it appears as though the meta-analysis by Sheppard et al1 mistakenly transposed outcomes from the Murphy et al2 manuscript in the data analysis. In the Murphy et al2 article, there was no significant difference between rate of ventriculitis in those who received a prolonged antibiotic course (ventriculitis rate 1.1%) and those who received only 1 perioperative dose of antibiotic (ventriculitis rate 0.4%). In Figure 1 in Sheppard et al,1 the authors appear to have input incorrect data into their calculations, citing 13 cases of ventriculitis in the Murphy et al2 control group and 0 in the prolonged antibiotic group. If this inaccuracy were corrected, it would presumably remove the protective effect of prolonged antibiotics cited by Sheppard et al.1 The goal of surgical antibiotic prophylaxis is to kill bacteria at the surgical site at the time of surgery. Antibiotics are not able to sterilize the area of surgical incisions and thus are limited in their role in prophylaxis. Administering a short course of antibiotics for prophylaxis can help kill sensitive bacteria colonizing the area of the surgical incision, but prolonging antibiotic exposure for prophylaxis increases selective pressure on the microbiome and allows for overgrowth and increased colonization of the patient with resistant organisms including at the surgical site itself. After the potential initial benefit from the initial antibiotic dose, prolonging prophylactic antibiotics increases risk of resistance and antibiotic side effects while not offering added protection from infection. Other improvements in SSI prevention such as preoperative optimization of patient health, practices to minimize the bioburden in the operative field, local antiseptic preparation of the surgical site, and improved postoperative wound care are safe and effective ways of minimizing the risk of SSIs without selecting for antibiotic resistance or placing the patient at risk for drug side effects such as nephrotoxicity, rash, and Clostridiodes difficile infection. The topic of surgical antibiotic prophylaxis duration is an important one as antibiotic resistance is a serious global threat brought on by antibiotic use, and if antibiotics offer no benefit to patients, they should not be used. This meta-analysis is very important as it will impact provider's practices. We are highly concerned that the findings of this manuscript were based on an error in data entry and must be revisited. Disclosures The author has no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.