Efficacy of Vancomycin, Teicoplanin and Fusidic Acid as Prophylactic Agents in Prevention of Vascular Graft Infection: An Experimental Study in Rat

Pre-clinical in vivo Models of Vascular Graft Coating in the Prevention of Vascular Graft Infection: A Systematic Review

OBJECTIVE

Vascular graft infection (VGI) remains an important complication with a high mortality and morbidity rate. Currently, studies focusing on the role of vascular graft coatings in the prevention of VGI are scarce. Therefore, the aims of this study were to survey and summarise key features of pre-clinical in vivo models that have been used to investigate coating strategies to prevent VGI and to set up an ideal model that can be used in future preclinical research.

DATA SOURCES

A systematic review was conducted in accordance with the Preferred reporting items for Systematic Reviews and Meta-Analysis guidelines. A comprehensive search was performed in MEDLINE (PubMed), Embase, and Web of Science.

REVIEW METHODS

For each database, a specific search strategy was developed. Quality was assessed with the Toxicological data Reliability Assessment Tool (ToxRTool). The type of animal model, graft, coating, and pathogen were summarised. The outcome assessment in each study was evaluated.

RESULTS

In total, 4 667 studies were identified, of which 94 papers focusing on in vivo testing were included. Staphylococcus aureus was the organism most used (n = 65; 67.7%). Most of the graft types were polyester grafts. Rifampicin was the most frequently used antibiotic coating (n = 43, 48.3%). In the outcome assessment, most studies mentioned colony forming unit count (n = 88; 91.7%) and clinical outcome (n = 72; 75%). According to the ToxRTool, 21 (22.3%, n = 21/94) studies were considered to be not reliable.

CONCLUSION

Currently published in vivo models are very miscellaneous. More attention should be paid to the methodology of these pre-clinical reports when transferring novel graft coatings into clinical practice. Variables used in pre-clinical reports (bacterial strain, duration of activity coating) do not correspond well to current clinical studies. Based on the results of this review, a proposal for a complete and comprehensive set up for pre-clinical invivo testing of anti-infectious properties of vascular graft coatings was defined.

The effects of ozone on bacterial growth and thiol-disulphide homeostasis in vascular graft infection caused by MRSA in rats

Purpose:

To investigate the microbiological, inflammatory and oxidant effects of adjuvant ozone administration in experimental rat vascular graft infection model which has not been previously investigated.

Methods:

Forty adult Wistar rats were divided into Sham, Control, Vancomycin, Ozone, Vancomycin+Ozone groups. Grafts were inoculated with Methicillin-resistant Staphylococcus aureus (MRSA) strain and implanted subcutaneously. Rats were treated intraperitoneally with ozone and /or intramuscularly with vancomycin for 10 days. Grafts were evaluated by quantitative bacterial cultures. Blood samples were harvested for determination of thiol-disulphide and cytokine profiles.

Results:

There was no significant difference in bacterial counts between Control and Ozone Groups. In the Ozone Group median colony count was significantly higher than the Vancomycin and Vancomycin+Ozone Groups. Total thiol and disulphide levels increased and disulphide/native thiol and disulphide/total thiol ratios decreased in Ozone Group significantly. Albumin levels decreased significantly in Vancomycin and Vancomycin+Ozone Groups compared to the Sham Group. IL-1 and TNF-alpha levels significantly increased in infected rats. Decreased levels of VEGF due to infection reversed by ozone therapy in control and vancomycin groups.

Conclusions:

We didn't observe any benefit of the agent on MRSA elimination in our model. Likewise, effects of ozone on thiol-disulphide homeostasis and inflammatory cytokines were contradictory.

Multidisciplinary Treatment Approach for Prosthetic Vascular Graft Infection in the Thoracic Aortic Area

Prosthetic vascular graft infection in the thoracic aortic area is a rare but serious complication. Adequate management of the complication is essential to increase the chance of success of open surgery. While surgical site infection is suggested as the root cause of the complication, it is also related to decreased host tolerance, especially as found in elderly patients. The handling of prosthetic vascular graft infection has been widely discussed to date. This paper mainly provides a summary of literature reports published within the past 5 years to discuss issues related to multidisciplinary treatment approaches, including surgical site infection, timing of onset, diagnostic methods, causative pathogens, auxiliary diagnostic methods, antibiotic treatment, anti-infective structures of vascular prostheses, surgical treatment, treatment strategy against infectious aortic aneurysms, future surgical treatment, postoperative systemic therapy, and antimicrobial stewardship. A thorough understanding of these issues will enable us to prevent prosthetic vascular graft infection in the thoracic aortic area as far as possible. In the event of its occurrence, the early introduction of appropriate treatment is expected to cure the disease without worsening of the underlying pathological condition.

Efficacy of linezolid, teicoplanin, and vancomycin in prevention of an experimental polytetrafluoroethylene graft infection model caused by methicillin-resistant Staphylococcus aureus

Background

The aim of this study was to evaluate the effectiveness of linezolid, teicoplanin, and vancomycin in prevention of prosthetic vascular graft infections in a vascular graft infection model.

Material/Methods

Fifty rats were divided into 5 groups. A polytetrafluoroethylene graft was implanted on the back of each rat. Methicillin-resistant Staphylococcus aureus (MRSA) strain was inoculated into all rats except Group 1. Group 2 was not given any treatment, Group 3 received linezolid, Group 4 received vancomycin, and Group 5 received teicoplanin. The grafts were removed for microbiological and histological examinations on the 7^th day. In addition, C-reactive protein and prealbumin levels and leukocyte counts in obtained blood specimens were determined.

Results

Group 1 did not have infection. Group 2 had bacteria 5.7×10⁴ CFU/cm². Group 3 and Group 4 had less bacterial growth. Group 5 had no bacterial growth. The number of bacteria was significantly higher in Group 2 than in the other experimental groups and the control group (p<0.001). Although there was no bacterial growth in Group 5, it did not significantly differ from Group 3 and Group 4. Group 2 had a significantly higher CRP level and leukocyte count and a significantly lower prealbumin level than the other groups.

Conclusions

Linezolid, teicoplanin, and vancomycin are effective in prevention of prosthetic vascular graft infections.

Measurement of teicoplanin by liquid chromatography-tandem mass spectrometry: development of a novel method

BACKGROUND

Teicoplanin is an antibiotic used for the treatment of endocarditis, osteomyelitis, septic arthritis and methicillin-resistant Staphylococcus aureus. Teicoplanin is emerging as a suitable alternative antibiotic to vancomycin, where their trough serum levels are monitored by immunoassay routinely. This is the first report detailing the development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for measuring teicoplanin in patients' serum.

METHODS

An Acquity™ UPLC (ultra-pressure liquid chromatography) tandem mass spectrometer was used to measure teicoplanin concentrations in samples from patients, quality assurance schemes and quality control preparations. Ristocetin was successfully implemented as a suitable internal standard. Ion suppression, linearity, stability, matrix effects, recovery, imprecision, lower limits of quantification and detection, interference and method comparison against immunoassay were all assessed.

RESULTS

Teicoplanin and ristocetin had elution times of 1.39 and 1.24 min, respectively. Ion suppression was shown to be negligible, and linear calibration curves (0-200 μg/mL) were consistently reproduced to have r(2) values >0.99. Postextraction stability was achieved up to 20 h, while matrix effects were minimal coupled with sample recovery of >93%. The lower limit of quantification was 1 μg/mL, and 0.2 μg/mL was the lower limit of detection. Interference with other antibiotics was dependent on the combination of drugs present in patients' serum. A method comparison between immunoassay and LC-MS/MS suggested a negative bias for tandem mass spectrometry.

CONCLUSIONS

This novel method of teicoplanin determination by LC-MS/MS is proven to be a robust protocol that is consistent and reproducible. Clinicians searching for alternatives in therapeutic drug monitoring may have an additional option that is potentially more accurate and specific.

Infections in vascular surgery

Infections in vascular surgery are usually of multifactorial nature resulting from a complex interplay of patient, surgical and environmental factors. Preventative measures initiated from the stage of pre-operative screening, maintenance of patient homeostasis and the use of organism-directed antibiotics can contribute to reduce infection rates. Graft preservation techniques are becoming increasingly popular as a method to treat established graft infections. In this article we report on the current trends and techniques on the management of infections in vascular surgery. Ongoing studies are required to continue to accumulate data on the effectiveness of these techniques.

Infection of hemodialysis arteriovenous grafts

PURPOSE

Prosthetic arteriovenous grafts (AVG) are bedeviled by significant infectious complications. This study was to determine the infectious complications of prosthetic AVG and review the relevant literature.

METHODS

All prosthetic AVG inserted between January 2000 to December 2007 were studied. Data on age, sex, date of graft insertion, indication for AVG, site of graft insertion, date of graft related infection, treatment and outcome for graft and patients were analyzed.

RESULTS

There were 84 AVG inserted into 58 patients. Thigh AVG accounted for 55% of cases whereas upper arm AVG was inserted in 39%. Thirteen (17.3%) AVG were associated with one or more episodes of infection. The infection rate for SynerGraft (50%) was statistically significantly different from that of PTFE (12%) - Yates' x2=6.164; df=1; p=0.013. The rate of infection was higher for thigh grafts (9/37) compared to other sites (4/34), but the difference was not statistically significant (Yates' x2=1.123; df=1; p=0.289). Only one death was directly related to AVG infection in this series.

CONCLUSION

Infectious complications of AVG require prompt surgical or radiological intervention to save life or access. The need to excise an infected graft completely is sometimes counterbalanced by the compelling need to provide vascular access for hemodialysis in a patient with limited access options.

Profilaxia antimicrobiana em cirurgia vascular periférica: cefalosporina ainda é o padrão-ouro?

Nas cirurgias vasculares periféricas, as cefalosporinas têm seu uso consagrado como agente antimicrobiano profilático de escolha. Recentemente, observamos uma mudança nos padrões de colonização, prevalência de patógenos e suscetibilidade geral aos antimicrobianos. Os patógenos multirresistentes vêm se tornando cada vez mais freqüentes nas infecções de ferida cirúrgica vascular, demonstrando variações regionais e locais quanto à suscetibilidade aos antimicrobianos profiláticos utilizados na rotina cirúrgica. Os dados e a literatura disponível até o momento demonstram que não existe evidência suficiente para uma mudança na rotina profilática perioperatória. Entretanto, devemos levar em consideração os padrões regionais e institucionais de prevalência de patógenos resistentes e padrões de suscetibilidade aos antimicrobianos para estabelecer guias e orientações específicas para a utilização de antimicrobianos profiláticos alternativos.

Surgical site and vascular infections: treatment and prophylaxis

Vascular infections typically include those of surgical sites, prosthetic grafts, and vascular ulcers, including some diabetic foot ulcers. Each of these infections represents a serious health concern, particularly among individuals with comorbid conditions who are at an increased risk of morbidity and mortality. Surgical site infections occur primarily as a result of contamination by skin organisms during surgery, whereas prosthetic graft infections result typically from a progressive wound infection. Diabetic foot ulcers and infections are especially complicated and difficult to treat. They occur in individuals with systemic illness that has compromising effects on the nervous, vascular, musculoskeletal, and immunologic systems. Vascular infections, like those elsewhere in the body, reflect an imbalance between the host and bacteria. Efforts to limit or prevent the likelihood of patients developing these infections centre on reducing the bacterial inoculum by means of asepsis and antisepsis. As well as size of the bacterial inoculum, the bacterial properties of pathogenicity and resulting virulence are also significant. The most frequent pathogenic bacteria encountered in surgical patients are Gram-positive cocci (e.g. Staphylococcus aureus and streptococci). Strains with multiple antibiotic resistance (e.g. meticillin resistant S. aureus [MRSA], S. epidermidis, and vancomycin-resistant enterococci [VRE]) can cause significant surgical site infection problems. Local resistance patterns and surveillance efforts are essential to ensure appropriate empiric antibiotic selection for prophylaxis or treatment.

Comparaison de différents biomatériaux destinés à la chirurgie vaginale dans un modèle in vivo d'infection de prothèse chez le rat

OBJECTIVES

The purpose of this study was to develop an animal model of prosthetic infection and compare in vivo bacterial infectiosity of different biomaterials used in vaginal surgery.

MATERIALS AND METHODS

We implanted 36 prostheses of poly(lactic acid) with 94% L forms (PLA94), in a model of incisional abdominal hernia in Wistar rats. Bacterial inoculation was done just after implantation with three strains of Escherichia coli of variable virulence, two different concentrations and two different times of inoculation (during surgery or 48 hours after). All meshes were explanted and animals sacrificed on day 30 after intervention. Bacteriology and histology were then performed. In the same way, three materials used in vaginal surgery (knitted light-weight polypropylene [PP], thermoformed PP [Uratape] and polyurethane coated poly[ethylene terephtalate] [PTFE]) were tested and compared to the PLA94 using the same protocol.

RESULTS

All inoculated prostheses were still infected at day 30 after implantation with the same E. coli strain. There was a significant difference in bacterial infectiosity linked to virulence of the inoculated strain (p=.005) and the amount injected (P<0.001). Infectiosity was significantly lower for PLA94 when compared to the three other prostheses (P=0.008). The most important infectiosity was seen with PTFE and thermoformed PP. For histologists, PLA94 also gave the weakest inflammatory reaction.

DISCUSSION AND CONCLUSION

An original animal model of prosthetic infection allowed us to compare in vivo bacterial infectiosity of different biomaterials used in vaginal surgery and to demonstrate that the PLA94 mesh induces a milder risk of infection than polypropylene.