Postoperative Infections Originate from Patients' Own Skin Microbiome, Not Hospital Contamination

Core Concepts

Postoperative infections are primarily caused by bacteria already present on the patient's skin, rather than from external hospital contamination.

Abstract

The study analyzed a cohort of 204 patients undergoing spinal surgery at Harborview Medical Center in Seattle between September 2019 and November 2020. Researchers took preoperative swabs from the nose, rectum, and skin at the operation site, determining bacterial strains through genomic sequencing. They then compared these data with the genome of bacterial populations isolated from any postoperative infections.
The key findings are:

In 86% of cases (19 of 22 strains isolated from 14 infection cases), the bacteria causing postoperative infections are genetically identical to those present before the operation on the patient's body.
A similar result was found for antibiotic resistances, which resembled those present in the patients' bacterial community.
An analysis of 59 postoperative infections from 1610 operated patients revealed that none of these infections originated from bacterial strains shared among patients, indicating they did not derive from a common source like the hospital environment.
The researchers also noted that the microbiome of the back is not homogeneous but varies along a gradient, with gram-positive opportunistic pathogens more prevalent in the cervical and thoracic regions, and gram-negative and anaerobic bacteria more prevalent in the lumbosacral region. The only significant difference found between male and female patients was a higher prevalence of Lactobacillus in the latter.
The results have important implications for the management of surgical prophylaxis and postoperative infections. The study suggests that efforts to reduce the incidence of infections should focus on the patient's microbiome, rather than solely on the sterility of the operating environment. Recommendations include analyzing the patient's microbiome to personalize preoperative antibiotic prophylaxis and using antiseptics like iodopovidone to target resistant bacterial strains.

Stats

In 86% of cases (19 of 22 strains isolated from 14 infection cases), the bacteria causing postoperative infections are genetically identical to those present before the operation on the patient's body.
An analysis of 59 postoperative infections from 1610 operated patients revealed that none of these infections originated from bacterial strains shared among patients.

Quotes

"The data indicate that most pathogens responsible for postoperative infections come from the bacterial flora of the patient, rather than from environmental contaminations during the surgical intervention."
"The results have important implications for the management of surgical prophylaxis and postoperative infections. That surgical infections mainly arose from a less than perfectly sterile operating environment was almost taken for granted. If, instead, endogenous bacteria are the true culprits, then efforts to reduce the incidence of infections should focus on the patient."

Key Insights Distilled From

Where Do Postoperative Infections Come From?

by Massimo Sand... at www.medscape.com 05-03-2024

https://www.medscape.com/viewarticle/where-do-postoperative-infections-come-2024a10008km

Deeper Inquiries

How can the personalization of preoperative antibiotic prophylaxis based on the patient's microbiome be implemented in clinical practice?

Personalizing preoperative antibiotic prophylaxis based on the patient's microbiome can be implemented in clinical practice through several steps. Firstly, before the surgery, samples can be taken from the patient's nose, rectum, and skin at the operation site to determine the bacterial strains present using metagenomics. Genomic sequencing of these samples can help identify the specific bacteria and their antibiotic resistance profiles. This information can then be used to tailor the antibiotic prophylaxis regimen for each patient. By considering the patient's specific bacterial composition and antibiotic resistances, healthcare providers can optimize the choice of antibiotics to effectively target potential pathogens while minimizing the risk of developing resistance.

What are the potential limitations or drawbacks of relying solely on the patient's microbiome to prevent postoperative infections, and how can a balanced approach be developed?

Relying solely on the patient's microbiome to prevent postoperative infections may have limitations and drawbacks. One potential limitation is the complexity and variability of the microbiome, which can make it challenging to accurately predict infection risks based on bacterial composition alone. Additionally, focusing only on the patient's microbiome may overlook other important factors contributing to infection risks, such as environmental contamination or surgical techniques. To develop a balanced approach, healthcare providers can combine microbiome analysis with other infection prevention strategies. This may include maintaining strict sterile protocols during surgery, optimizing wound care practices, and implementing targeted antibiotic prophylaxis based on both the patient's microbiome and surgical risk factors.

What other factors, beyond the patient's microbiome, might contribute to the risk of postoperative infections, and how can a more comprehensive understanding of these factors inform infection prevention strategies?

Beyond the patient's microbiome, several other factors can contribute to the risk of postoperative infections. These factors may include the surgical environment, surgical technique, duration of surgery, presence of foreign materials (such as implants), underlying health conditions of the patient, and postoperative care practices. A more comprehensive understanding of these factors can inform infection prevention strategies by allowing healthcare providers to implement multifaceted approaches. This may involve optimizing surgical protocols to minimize contamination, enhancing patient screening for infection risks, promoting proper wound care and hygiene practices, and monitoring patients closely for signs of infection postoperatively. By considering a wide range of factors influencing infection risks, healthcare providers can develop more effective and tailored strategies to prevent postoperative infections.