Sixty years after its introduction into clinical practice, vancomycin continues to be recommended intravenously as a treatment for severe and complicated infections and is the most common antibiotic agent used against perioperative infections when no other antibiotic was available. The implant-associated and SSI are among the most dreaded complications encountered by orthopedic surgeons, which are associated with increased length of hospital stay, decreased patient satisfaction, and increased morbidity and mortality. All these reasons further popularized the usage of vancomycin in orthopedics.
The \infection related with orthopedic surgery cause high medical, economic, and social costs. In one study of 36 patients with SSI after lumbar fusion surgery, treatment of SSI required an average of 2.1 operations per patient, and a total of 1121 days of extra hospitalization . The Gram-positive bacteria, especially Staphylococcus were the most frequent causes of these orthopedic-related infections. In many parts around the world, around 80% of S. epidermidis isolated from hospitalized patients are resistant to methicillin . In addition, the low cost of vancomycin and easy accessibility than other antibiotics also makes it a very attractive option, especially in developing countries .
The current study revealed that the main reasons for the orthopedic patients receiving intravenous vancomycin treatment were postoperative SSI for treatment. For the prophylaxis purpose, the most common reasons focus in postoperative suspicious infection with clinical signs, such as incision problem, pyrexia, extreme increase of CRP and ESR. The eradication of infections in orthopedics often requires long-term therapy for a duration of intravenous vancomycin usage [8, 12]. The mean duration of vancomycin medication was longer in Treatment than Prophylaxis group in our study.
Most of the spine and joint surgery are involved with biomedical implants, including spinal pedicle screw and joint prosthesis, which eases the development and progression of SSI. The SSI after spine surgery was the most common cause (51.5%) for vancomycin treatment medication in our study. According to a study involve a large group of more than 108,000 patients, superficial and deep SSI after spine surgery were found in 0.8% and 1.3% of patients, respectively . A meta-analysis  revealed that the rates of S. aureus, S. epidermidis and methicillin-resistant Staphylococci for SSI after spine surgery were 37.9%, 22.7% and 23.1%, respectively. For genus level, the rates of Staphylococcus, Enterococcus, Streptococcus were 50.2%, 8.2% and 6.9%, respectively. Some authors also reported that the microbiology of SSI in spine surgery is predominantly S. aureus and S. epidermidis [15, 16]. In the current study, for the cases in the Spine group, the infection was mostly due to S. epidermidis (37.0%), S. aureus (21.7%), and MRSA (8.7%).
Many reports have revealed that Gram-positive cocci, especially S. aureus and coagulase-negative staphylococci (CNS) were the most common infective organisms for PJI [17–19]. Empirical antibiotic treatment of early PJIs include coverage of vancomycin was recommended until definitive culture results become available . In a prospective cohort study of microbiologic epidemiology of PJI, the results revealed 28.9% of S. aureus, 28.6% of CNS, 14.1% of Enterobacteriaceae and 13.1% of streptococci . In our research, the cases in Joint subgroup receiving vancomycin were mostly PJI after TKA and THA, followed by SSI after other joint surgery. These infections were mostly due to S. aureus (39.3%), S. epidermidis (32.8%) and MRSA (6.6%).
In the current study, S. epidermidis was the main cause for spine cases receiving vancomycin treatment, which was different from S. aureus responsible for joint cases. The microbiological results were consistent with previous reports related with PJI and SSI after spine surgery. In addition, the duration of vancomycin treatment was longer for MRSA than S. epidermidis (P = 0.03) and S. aureus (P = 0.14).
Empirical vancomycin treatment should be stopped when available culture results fail to reveal β-lactam-resistant Gram-positive bacterial infections. So, it is regarded as inappropriate that the empirical vancomycin use is continued for a proportion of patients . Misan et al reported that 97% of the patients receiving vancomycin for prophylaxis purposes were classified as inappropriate use .
No matter treatment or prophylactic medication, vancomycin, as an antibiotic, was used to achieve the ultimate goal of eradicating infection. For the certain infection, vancomycin was used for the purpose of treatment. However, for some clinical suspicious infection, it was also important and urgent to use vancomycin to prevent the infections and avoid serious consequences. Based on the HICPAC criteria, vancomycin use was documented to be treatment and prophylactic in 89.4% and 10.6% patients, respectively .
In the current study, 54.6% of the cases were for treatment and 45.4% were for prophylaxis. Prophylaxis medication should target the most common organisms for SSI in orthopedics, including S. aureus and S. epidermidis. However, the bacterial culture may be negative in some infection cases. In 23.2% of patients with PJI, no bacteria were detected despite clinical suspicion of an infection . Given the disastrous consequences of SSI following joint and spine surgery, vancomycin was still continued until the clinical sign of infection was alleviated.
There were also some limitations for the study. First, this was the retrospective study in single center with limited cases number. As for the investigation of drug usage, a large number of cases from multicenter could be more important and convincing. Second, as regard to the prophylaxis mediation of intravenous vancomycin in our study, some controversy maybe exist and need further analysis. A perfect monitor system could be set and maybe a good method to monitor and guide the standardized vancomycin use.