RU2611407C2 - Diagnostic technique for near-graft infection of joints - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to diagnostics, and can be used for diagnosing near-graft infection of joints. For this purpose, extracted implants are intensely shaken in working solution for producing of bacterial suspension for 30 seconds, followed by ultrasound treatment during 5 minutes. It is additionally intensely shaken for 30 seconds with subsequent sowing of produced flushing fluid to sow on nutritional mediums in accordance with known microbiological techniques, cultures are visually observed daily for growth of microorganisms (aerobic and anaerobic organisms) with further identification and determination of microorganism sensitivity to antibacterial preparations, wherein working solution to obtain flush fluid for sowing is 0.9 % NaCl solution, and visual observation of cultures is carried out for 14 days.

EFFECT: method enables detecting clinically significant pathogens, including slow growing and difficult culturing, with high accuracy and availability.

1 cl, 1 tbl

Description

The invention relates to medicine, in particular to the diagnosis of joint infections using ultrasonic waves, and can be used to detect periprosthetic joint infections during joint replacement.

Recently, the number of joint arthroplasty operations has significantly increased worldwide. The annual increase in such manipulations in European countries varies between 5.3% -17%. The intensive development of endoprosthetics entails an increase in the number of revisions due to the development of various complications. One of the most common is periprosthetic joint infection (IPR). According to domestic and foreign authors, infectious complications in endoprosthetics range from 0.3% to 2% in primary endoprosthetics and 40% or more in revision ones. In addition to economic costs, which increase 3-4 times, in 30% of cases purulent complications lead to catastrophic consequences in the form of removal of the prosthesis, the development of chronic post-implantation osteomyelitis and permanent disability.

A feature of the pathogenesis of periprosthetic infection is that microorganisms are usually located on implants as part of biofilms - a mono-or association of cultures of microorganisms and extracellular matrix, which is a complex biochemical mixture of polysaccharides, glycopeptides, nucleic acids and lipids. The essence of the existence of a biofilm is the protection of microorganisms in it from adverse environmental factors. Microbial aggregation makes the structure more voluminous and inaccessible to phagocytosis, and key antigens are “closed” to antibodies by the extracellular matrix.

Also, the elements of the matrix slow down the diffusion of antibacterial drugs through the biofilm and actively bind antibiotics.

The localization of damaged bacteria is limited to the surface layers of the biofilm, and in the inner layers of damaged cells it becomes much smaller. The microorganisms that are part of biofilms are 10-100 times less sensitive to antibacterial drugs, especially to inhibitors of the bacterial cell wall synthesis, since most biofilm microorganisms are in the inactive phase of the life cycle (persisters).

Ultrasound is used to destroy biofilms on the surface of implants and thereby increase the detection of pathogens. The extracted component of the implant is placed in a sterile container, and a solution is added there (nutrient broth, etc.). After intensive shaking of the implant in the liquid, the container is immersed in an ultrasonic bath. Using low-frequency ultrasonic vibrations of low intensity, the implant is irradiated. After repeated vigorous agitation, the ultrasonically treated liquid is sown on culture media in accordance with the approved microbiological methods.

Known methods for diagnosing periprosthetic joint infection, including intensive shaking of the extracted implants in the working solution to obtain bacterial suspension for 30 seconds, followed by ultrasonic treatment for 5 minutes, additional intensive shaking for 30 seconds, followed by plating the resulting solution of bacterial suspension on nutrient media in in accordance with known microbiological techniques, daily visual observation of crops for the presence of microorganism growth isms to 14 days, with further identification and determination of antibiotic susceptibility of microorganisms isolated [1, 2].

In the known methods, several types of working solutions are used, which are added to containers with extracted implants, namely Ringer's solution, at a frequency of ultrasonic vibrations of 40 ± 2 kHz (method sensitivity was 78.5%, specificity 98.8%) or thioglycol broth, with the frequency of ultrasonic vibrations of 40 ± 5 kHz (the sensitivity of the method when using this nutrient medium is 71%, specificity is 92%.

The disadvantages of the known methods for diagnosing periprosthetic joint infection is the need for preliminary preparation of a working solution followed by sterilization, which requires the availability of special equipment (a medium cooker, an autoclave), which is not acceptable for all diagnostic laboratories. The purchase of finished media from commercial manufacturers also has limitations (high cost, delivery time and shelf life of culture media, packaging, etc.).

The technical result is to reduce the time of diagnosis, cheaper diagnostic method, which ensures the availability of the method of research of the extracted implants in the diagnosis of periprosthetic joint infection, without using special equipment.

The technical result is achieved in that in a method for diagnosing periprosthetic joint infection, including intensive shaking of the extracted implants in the working solution to obtain bacterial suspension for 30 seconds, followed by ultrasonic treatment for 5 minutes, additional intensive shaking, followed by plating the resulting bacterial suspension solution on nutrient environments in accordance with known microbiological techniques, daily visual observation of crops in stock growth of microorganisms for 14 days, with further identification and determination of antibiotic susceptibility of microorganisms isolated according to the invention as a working solution to obtain a bacterial suspension using a 0.9% solution of NaCl.

During ultrasonic treatment of the extracted implants in the working solution, a frequency of ultrasonic vibrations of 37-40 kHz is used to obtain a bacterial suspension.

The method is as follows.

The implants removed from the patient’s operating room are placed in sterile plastic bags and immediately delivered to the laboratory for examination.

Then, sterile 0.9% NaCl solution in an amount of 50 to 200 ml is added to sterile packages with implants, depending on the size of the implant component, after which the implant is intensively agitated in this working solution for 30 seconds.

Next, packages with implants are subjected to ultrasonic treatment for 5 min at a frequency of ultrasonic vibrations of 37 kHz, after which repeated intensive shaking of the contents of the package is carried out for 30 seconds. Ultrasound-treated liquid is sown on nutrient media (blood ogre, thioglec media and in bottles for an automatic analyzer for aerobic and anaerobic microorganisms). Crops are incubated in a thermostat at 35 degrees up to 14 days and carry out daily visual monitoring of crops for the presence of microorganism growth with further identification and determination of the antibiotic sensitivity of the isolated microorganisms.

In laboratory conditions, the effectiveness of using 0.9% NaCl solution as an ultrasonic treatment of implants was evaluated as a working solution. The sensitivity of the method was 95%, specificity - 90%.

As can be seen from the table, the number of bacteriologically confirmed cases of periprosthetic joint infection (IPR) when using 0.9% NaCl as a working solution is higher (92%) than when using Ringer's solution (78.5%) and thioglycol broth (71%) . Also in the group of patients with presumably aseptic instability of implants in 8%, clinically significant microorganisms were detected. These patients with suspected aseptic instability of endoprosthesis components were diagnosed with periprosthetic infection.

The inventive diagnostic method is easy to use, it allows to shorten the diagnostic time, reduce labor costs and funds, which ensures the availability of the method of investigation of the extracted implants in the diagnosis of periprosthetic joint infection, without using special equipment and using a solution of the known cheap NaCl salt as a working solution.

Information sources

1. Trampuz A, Piper KE, Jacobson MJ et al. Sonication of removed hip and knee prostheses for diagnosis of infection. N. Engl. J. Med 2007; 357: 654-663.

2. Portillo ME, Salvado M, TrampuzA et al. Sonication versus vortexing of implants for diagnosis of prosthetic joint infection. J. Clin. Microbiol 2013 51: 591-594.

Claims (1)

A method for diagnosing periprosthetic joint infection, including intensive shaking of the extracted implants in the working solution to obtain flushing fluid for sowing for 30 seconds, followed by ultrasonic treatment for 5 minutes, additional intensive shaking for 30 seconds, followed by sowing the resulting flushing fluid for inoculation on nutrient medium in accordance with known microbiological methods, daily visual observation of crops for the presence of microorganisms ( eroby and anaerobes) with further identification and determination of microbial sensitivity to antibiotics, characterized in that as the working solution for flushing liquid used for seeding a solution of 0.9% NaCl, and daily visual observation of crops spend up to 14 days.