Molecular Genetic Analysis of Perioperative Colonization by Infection-Related Microorganisms in Patients Receiving Intraoral Microvascular Grafts

Abstract

Background/Objectives: In oral and maxillofacial surgery, the reconstruction of defects often involves the transfer of skin tissue into the oral cavity utilizing microvascular grafts. This study investigates postoperative changes in microbial colonization following intraoral microvascular transplantation, as well as potential influencing factors. Methods: In 37 patients undergoing intraoral reconstructions, pre- and postoperative swabs were taken from the donor and recipient regions to quantify the seven selected marker bacteria using TaqMan PCRs. Patient-specific factors and clinical data were also recorded. Results: The infection-associated Acinetobacter baumannii tended to decrease postoperatively, while the infectious pathogens Pseudomonas aeruginosa, Enterococcus faecalis and the family of Enterobacteriaceae showed a postoperative increase without being directly associated with a clinical infection. Streptococcus mitis showed a significant postoperative decrease on buccal mucosa and increase on the graft surface (oral dysbiosis) and was significantly reduced or displaced by other bacteria (e.g., Mycoplasma salivarium, positive selection) when treated with ampicillin/sulbactam. Conclusions: The cutaneous microbiome of the graft adapts to the local intraoral environment. Postoperative shifts in oral bacterial colonization and an increase in infection-relevant bacteria were observed. These perioperative changes in colonization are also influenced by the administration of ampicillin/sulbactam. Consequently, single doses of antibiotics appear to be more beneficial compared to longer-term preventive use.

Keywords: antibiotics; microvascular reconstruction; oral microbiome.

Figure 1

Difference in the respective load of bacteria detection in relation to the reference swab W0; Shown are the swabs from the cheek (W), graft (T) and suture (N) at the preoperative time point (0), early postoperative time point (1) and late postoperative time point (2), +++ = Highly increased bacterial load (Δ [X] − [W0] > 1 × 10⁶ GE/sample); ++ = Moderately increased bacterial load (Δ [X] − [W0] > 1 × 10³ and < 1 × 10⁶ GE/sample); + = Slightly increased bacterial load (Δ [X] − [W0] > 0 and < 1 × 10³ GE/sample); 0 = No positive evidence; - = Slightly reduced bacterial load (Δ [X] − [W0] > −1 × 10³ and <0 to GE/sample), -- = Moderately reduced bacterial load (Δ [X] − [W0] > −1 × 10⁶ and < −1 × 10³ GE/sample); --- Highly reduced bacterial load (Δ [X] − [W0] > −1 × 10⁶ GE/sample); Ø = No data available.

Figure 2

Exemplary results of quantitative bacterial detections (GE/sample) of S. mitis, M. salivarium, Enterobacteriaceae and A. baumannii; the results of all 37 participants are shown on cheek (W), graft (T) and suture swab (N) at the preoperative time point (0), early postoperative time point (1) and late postoperative time point (2). * p <0.05; ** p <0.01.

Figure 3

Perioperative leukocyte counts (left) and perioperative C-reactive protein values (right) of all study participants. ** p <0.01; *** p <0.001.