Clinical value of pin-bone interface surface culture in diagnosis of pin tract infection in external fixation
10.3760/cma.j.cn115530-20240224-00086
- VernacularTitle:钉-骨界面表面培养在外固定支架钉道感染诊断中的应用价值
- Author:
Yongyi HUANG
1
;
Nan JIANG
;
Chensheng SONG
;
Yu YAO
;
Bowei WANG
;
Yanjun HU
Author Information
1. 南方医科大学南方医院骨科-创伤骨科，广州 510515
- Keywords:
Bone diseases, infectious;
External fixators;
Microbiological techniques;
Pin tract infection;
Pin-bone interface
- From:
Chinese Journal of Orthopaedic Trauma
2024;26(6):519-524
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To evaluate the pin-bone interface surface culture in the diagnosis of pin tract infection in external fixation.Methods:A prospective observational study was conducted to enroll the patients who underwent either partial or complete removal of external fixators after external fixation at Department of Orthopaedic Trauma, Nanfang Hospital, Southern Medical University from June 2023 to September 2023. The secretions from the pin track (pin-soft tissue interface) were plated for bacterial culture. Additionally, the surface of the pins placed within the bone (pin-bone interface) was cultured directly with tryptic soy agar (TSA). Positive cases were subjected to additional analysis using qualitative microbial culture and antibiotic susceptibility testing. Comparisons were made between the cultural results derived from both interfaces.Results:The present study enrolled 23 patients [18 males and 5 females with an age of (37.3±17.6) years] and a duration of bearing external fixation of 8.1 (4.0, 11.3) months. A total of 212 samples were cultured. The positive rate of bacterial culture at the pin-soft tissue interface was 53.8% (57/106), significantly higher than that at the pin-bone interface [17.9% (19/106)] ( P<0.05). No correlation was found in the results of bacterial culture between the pin-bone interface and the pin-soft tissue interface ( r=-0.011, P=0.913). In terms of bacterial strains, single pathogenic bacteria were found in all the 19 positive samples cultured at the pin-bone interface, with Staphylococcus aureus as the most common pathogenic bacteria (7); of the 57 positive samples cultured at the pin-soft tissue interface, single pathogen infection was found in 51 and mixed bacterial infection in 6. Positive culture was found at both interfaces in 10 samples, of which identical bacterial strains were found in 4 and partially identical bacterial strains in 1. A total of 82 bacterial samples were subjected to drug sensitivity testing, of which 74.4% (61/82) were infected with Staphylococcus. The drug sensitivity test of Staphylococcus showed that the top 3 resistant drugs were ampicillin, oxacillin, and penicillin. The top 3 sensitive drugs were vancomycin, teicoplanin, and linezolid, all of which showed little resistance. Conclusions:Pin-bone interface culture of external fixators is a necessary evaluation of the infection of deep bone tissue. Simultaneous culture of pin-bone interface and pin-soft tissue interface can provide more comprehensive basis for the treatment of pin tract infection.
