Local anesthetic infiltration is used widely for post-operative analgesia in many situations. However the effects of local anesthetics on wound healing are not demonstrated clearly. This study planned to evaluate the effects of lidocaine, prilocaine, bupivacaine and levobupivacaine on wound healing, primarily on wound tensile strength and on collagen ultrastructure. This study was conducted on male Sprague Dawley rats. On days 0, 8th, 15th, and 21st, all animals were weighed and received a preincisional subcutaneous infiltration of 3 mL of a solution according the group. Control saline (C), lidocaine (L) 7 mg.kg⁻¹, prilocaine (P) 2 mg.kg⁻¹, bupivacaine (B) 2 mg.kg⁻¹ and levobupivacaine (LVB) 2.5 mg.kg⁻¹. The infiltrations were done at the back region 1.5 cm where incision would be performed at the upper, middle and lower part along the midline, under general anesthesia. Wound tensile strengths were measured after 0.7 cm × 2 cm of cutaneous and subcutaneous tissue samples were obtained vertical to incision from infiltrated regions. Tissue samples were also obtained for electron microscopic examination. Evaluations were on the 8th, 15th and 21st days after infiltration. There was no difference between groups in the weights of the rats at the 0th, 8th, 15th and 21st days. The collagen maturation was no statistically different between groups at the 8th and 15th days. The maturation scores of the B and L groups at the 21st day was significantly lower than the Group C (1.40, 1.64 and 3.56; respectively). The wound tensile strength was no statistically different between groups at the 8th and 15th days but at the 21st day the Groups B and LVB had significantly lower value than Group C (5.42, 5.54 and 6.75; respectively). Lidocaine and prilocaine do not affect wound healing and, bupivacaine and levobupivacaine affect negatively especially at the late period.

In this study, we aimed to compare the antimicrobial effects of bupivacaine and fentanyl citrate and to reveal the impact on antimicrobial effect potential in the case of combined use. In vitro prospective study. University Clinical Microbiology Laboratory. In our study, in vitro antimicrobial effect of 0.05 mg.mL^-1 fentanyl citrate, 5 mg.mL^-1 bupivacaine were tested against Staphylococcus aureus American Type Culture Collection (ATCC) 29213, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 13883, Escherichia coli ATCC 25922 and Candida albicans ATCC 10231 as Group F (Fentanyl Citrate) and Group B (Bupivacaine), respectively. S. aureus ATCC 29213, P. aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 13883 and Escherichia coli ATCC 25922 were cultured onto Mueller Hinton agar (Oxoid, UK) plates and Candida albicans ATCC 10231 were cultured onto Sabouraud dextrose agar (Oxoid, UK) plates for 18−24 hours at 37 °C. In terms of inhibition zone diameters, S. Aureus ATCC 29213, P. aeruginosa ATCC 27853, and C. albicans ATCC10231 values obtained after 12 and 24 hours of incubation ​​were significantly higher in Group F than Group B (p < 0.001). In terms of inhibition zone diameters, E. coli ATCC 25922, and K. pneumomiae ATCC 13883 values obtained after 12 and 24 hours of incubation ​​were significantly higher in Group B than Group F (p < 0.001, E. coli 12ª hour p = 0.005). Addition of fentanyl to Local Anesthetics (LAs) is often preferred in regional anesthesia applications in today's practice owing especially to its effect on decreasing the local anesthetic dose and increasing analgesia quality and patient satisfaction. However, when the fact that fentanyl antagonized the antimicrobial effects of LAs in the studies is taken into account, it might be though that it contributes to an increase in infection complications. When the fact that fentanyl citrate which was used in our study and included hydrochloric acid and sodium hydroxide as protective agents, broadened the antimicrobial effect spectrum of LAs, had no antagonistic effect and showed a synergistic antimicrobial effect against E. Coli is considered, we are of the opinion that the addition of fentanyl to LAs would contribute significantly in preventing the increasing regional anesthesia infection complications.

Study Objective: Aim of this study was to evaluate antimicrobial effects and interaction between analgesic combinations of fentanyl citrate, dexmedetomidine hydrochloride and tramadol hydrochloride on Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Candida albicans which are some of the most common nosocomial infection related microorganisms. Design: In vitro prospective study. Setting: University Clinical Microbiology Laboratory. Measurements: In order to evaluate in vitro antimicrobial effects and interaction between analgesic combinations, tramadol hydrochloride, fentanyl citrate and dexmedetomidin were used against S. aureus ATCC 29213, K. pneumoniae, E. coli ATCC 25922, P. aeruginosa ATCC 27853 and C. albicans ATCC 10231 standard strains by microdilution method. Main Results: According to microdilution assays tramadol has shown the most efficient antimicrobial activity also it has been observed that 10 mg/ml concentrated dexmedetomidine has antimicrobial effects on S. aureus, K. pneumoniae and P. aeruginosa. Fentanyl has displayed evident inhibitory potency on the pathogens except for Klebsiella pneumoniae, nevertheless our predefined minimum concentration inhibited growth by 9.5 %. Fentanyl and dexmedetomidine together exhibited more antimicrobial effect on P. aeruginosa and E. coli growth. Additionally, when the three drugs examined together, microbial inhibition occurred more than expected on E. coli again and also on C. albicans growth. Conclusions: Our results revealed the antimicrobial properties and synergy with the different combinations of fentanyl, dexmedetomidine and tramadol against the most common nosocomial infection agents in the ICU. This is the first study in the literature looking into the microbial “interactions” of opioids and sedative drugs but more research is needed in order to define clinico-laboratory correlation. ©2021 by the authors. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/).