THE NEW METALL-BETA-LACTAMASE’S INHIBITOR EFFICACY IN A MODEL SYSTEM IN VITRO

The Enterobacteriaceae antibiotics resistance depends on a combination of several mechanisms, such as the beta-lactamases overproduction, the microbial cell reduction outer membrane permeability (usually associated with loss of protein porin), the presence of efflux systems. Particularly noteworthy are the metallo-beta-lactamases (MBL) whose presence causes resistance of gram-negative microorganisms to all beta-lactam antibiotics (in some cases except aztreonam). Currently there are no MBL inhibitors permitted for use in the clinic. The effective inhibitors search for carbapenem-resistant bacteria’ MBL authorized for use in the clinic and reinforcing effects of carbapenems, served as the basis for the present study. The work was carried out in three stages: 1) creating a model system using a standard enzyme reagent metallo-beta-lactamase P. aeruginosa recombinant expressed in E. coli, to evaluate the increasing of minimal inhibitory concentrations (MIC) of carbapenems against previously sensitive Gram-negative microorganisms strains in vitro; 2) evaluation of MBL promising inhibitors in the presence of the same standard enzyme reagent; 3) evaluation of the ability of the identified inhibitors increase the carbapenems effects against clinical isolates of Gram-negative microorganisms producing MBL, in terms of the their MIC and fractional inhibitory concentration index (FIC index). The checkerboard array was modified to evaluate the combined use of carbapenems and potential MBL inhibitor — a drug from the group of bisphosphonates — etidronic acid. Using a standard enzyme reagent metallo-beta-lactamase P. aeruginosa recombinant expressed in E. coli, we created a model system that allows to assess the prospects of new inhibitors MBL gram-negative microorganisms. A dose-dependent effect of increasing the meropenem level MIC from reagent MBL quantity in a model system against previously antibiotic sensitive reference strains of microorganisms was revealed. MBL enzyme inactivation was noted in the presence of even small doses of bisphosphonate, in the tests the appearance of logarithmic phase of P. aeru ginosa ATCC 27853 growth was shown delayed up to 12 hours compared to the control. In this case the maximum dose of etidronic acid 50 000–100 000 μg/ml completely inhibited the MBL, there was no a log phase microbe’s growth due to the effect of meropenem on the reference level of sensitivity (2 μg/ml). The synergistic effect (FIC index < 0.5) of combined meropenem with etidronic acid use was identified against clinical isolates Gram-negative microorganisms resistant to carbapenems and producing MBL, wherein the enhancing action of the antibiotic was more 8–512 times compared with the initial MIC levels

PROBIOTIC-BASED SANITATION AS ALTERNATIVES TO CHEMICAL DISINFECTANTS

It is known that any surfaces in environment of healthcare organizations are a reservoir for microorganisms and contribute to transmission of pathogens, increasing the risk of cross-contamination through indirect contact with the patient. Wide and not always rational use of chemical disinfectants carries risks for the safety of the environment, the patient and medical staff. In this regard, there remains the search for alternative methods of purification and decontamination of abiotic surfaces in health care facilities. Tested the tool for cleaning areas that contain 3 strains of the genus Bacillus: B. subtillis, B. licheniformis, B. pumilus. Were treated areas of the medical centre in St. Petersburg Pasteur Institute: the treatment room (experience) and the office of the gynecologist (control with conventional cleaning and disinfection). Within 30 days of the sowing of samples of swabs from surfaces were made of 3 Petri dishes with the “blood” agar-based environment “agar of Givental–Witch” debilitating touch (gold method). Isolated cultures of bacteria identified by microscopy, biochemical typing and MALDI-TOF MS (Bruker). In control and the experience in the 1st day of observation prior to the cleaning sown Enterococcus faecium 104 –105 CFU/ml. The 2nd day of observation in the control was dominated by E. faecium, then his growth stopped. For the 2nd–4th day watched the growth of Enterobacteriaceae to 106 CFU/ml, in the future, the number was 10 CFU/ml until the end of the observation period (30 days). The 5th day in the control revealed the growth of bacteria of the genus Staphylococcus spp. mainly S. epidermidis. The experience from the 2nd day of observation revealed a significant increase in Bacillus spp. at 105 CFU/ml, then before the end of the experiment, the number was 102 –103 CFU/ml. In the 1st–2nd day revealed growth of E. faecium, and then it stopped. For the 2nd–4th day watched the growth of Enterobacteriaceae to the level of 106 CFU/ml, on the 8th day — to 102 CFU/ml, the growth of conditionally pathogenic microflora was absent. Cleaning of the premises on the basis of probiotic bacteria of the genus Bacillus inhibits the growth of sanitary-indicative microorganisms compared to control. Thus, the means of probiotic treatment did not have a biocidal effect, but inhabiting the surface, they inhibit the growth and proliferation of opportunistic bacteria

TIME-KILL ASSAY: AN EFFICACY OF SYNERGY BETWEEN CARBAPENEMS AND CLODRONIC ACID

Abstract. Currently, a search for augmenting antibiotics activity is still crucial due to elevated frequency of detecting carbapenem-resistant Gran-positive bacterial isolates. To resolve this, it might be reasonable to combine carbapenems metal-â-lactamase (MâL) inhibitors. Unfortunately, no MâL inhibitors approved for treatment of carbapenem-resistant infections are currently available. Pathogenic bacteria may survive antibiotic attack, exert tolerance and persistence accompanied with the ongoing infectious process. In connection with this, determining dependence between antimicrobialrelated bactericidal effect and exposure time on microbes at 4, 8, 12 and 24 hours after the onset, a so called time-kill assay, is necessary. A synergy between both agents was noted upon reduced microbial population by ≥ 3 log10. A checkerboard array followed by seeding the microplate well contents onto a dense nutrient medium at various time points were used to assess a synergistic efficacy of carbapenems applied together with clodronic acid against MâL-producing VIMgenotype P. aeruginosa 532/14 clinical isolate obtained from patients with infectious complications (minimal inhibitory concentrations [MIC] for imipenem or meropenem were 512 μg/ml), microbial burden 106 CFU/ml. Optical density was measured at two wavelengths (490 and 630 nm) in ELx800 reader, within 4–24 hour exposure time to determine time of logarithmic growth phase emerging in test culture. It is noteworthy that magnitude of optical density is a difference between two bichromatic measurements resulting in remarkably reduced inaccuracy due to scratches or fingerprints left on the plate. It was found that clodronic acid exhibited a synergic bactericidal effect with carbapenems against a clinically resistant MâL-producing VIM-genotype P. aeruginosa 532/14 strain. Upon that, imipenem-related antimicrobial activity was evident as early as 8 hours after the onset decreasing cell growth down to 1.4 log10 compared to control, whereas 12 hours later it resulted in total inhibition of test strain by decreasing growth of the test strain by 6 log10. Meropenem in combination with clodronic acid showed a more pronounced activity: complete absence of P. aeruginosa 532/14 growth by 8 hours of incubation, growth suppression by 3.2 log10, which reached 6 log10 12–24 hours after the onset. Time-kill assay allows to identify efficient combinations of carbapenems and MâL inhibitors, which is of great importance for increasing therapeutic efficacy of patients with severe purulent-septic complications

MODERN ANTICEPTIC HYDROGEL IN TREATMENT OF INFECTIOUS COMPLICATIONS OF WOUNDS IN SURGERY

Treatment and prevention of infectious complications remain the actual problems of surgery. Purulent complications very often arise in operative interventions with an application of various fixing devices. A study of the adhesive surgical antiseptic (ASA) «ARGAKOL» (Registration certificate № FS 012б2005/1878-05) was completed. The results of the preliminary antimicrobial activity of the developed composition showed that ASA «ARGAKOL» had a broad spectrum of antimicrobial action. There was used the method of twofold serial dilutions in a liquid medium and Cup-suspension. The study of the influence of the ASA «ARGAKOL» on the wound healing was made in the experiment on white outbred rats. There were carried out two series of experiments with 10 rats in each group: on the model of just contaminated wound (the first series) and on the model of infected wound with delayed application of the glue (after 3 days) after trauma (the second series)

BIOMETRIC ASPECTS IN TREATMENT OF COMBINED TRAUMA

The objective is to determine the optimal tactics in treatment of combined trauma using the objective assessment of the severity of injuries and the overall condition of the casualties.Material and methods. The article presents the materials on biometric analysis of treatment of casualties with combined trauma in the program of multi-staged surgical treatment.Results. In the process of multi-staged surgical treatment, we can determine the prognosis, the nature of the traumatic disease with the help of a biometric comprehensive study that will optimize comprehensive treatment program and rehabilitation of casualties in the trauma center of the 1st level.Conclusion. The conditions for the application of the full spectrum of surgical interventions in the maxillofacial region in the acute period of traumatic disease are created in favorable prognosis. The choice of treatment in favorable or unfavorable prognosis is a multistaged surgical tactics of treatment – Damage control surgery

THE ANTIMICROBIAL BIODEGRADABLE COMPOSITION BASED ON HIGH-MOLECULAR WEIGHT POLYVINYLPYRROLIDONE FOR THE PROPHYLAXIS OF EXPERIMENTAL OSTHEOMYELITIS

The aim of study was to evaluate the efficacy of antimicrobial composition of amikacin with dioxydin and polyvinylpyrrolidone as a biodegradable prolonging agent for the post-surgery infections prophylaxis. The data obtained show the efficacy of the amikacin combination with dioxydin based on high-molecular weight polyvinylpyrrolidone and an opportunity to it's application for the post-surgery infections prophylaxis in traumatology, orthopedics and other surgery areas

EFFECTS OF PROLINE-RICH PEPTIDES OF THE INNATE IMMUNE SYSTEM ON DRUG-RESISTANT BACTERIAL STRAINS

Resistance of pathogenic microorganisms to conventional antibiotics is growing rapidly in recent years, accompanying with an increase of mortality caused by hospital-acquired infections. Therefore, a search for novel drugs to combat antibiotic resistant bacteria is one of the priorities in biomedicine. Natural compounds which are contained in host defense effector cells of humans and animals, may serve as prototypes for developing principally new antibiotics. Such compounds include antimicrobial peptides of innate immunity, in particular, a group of proline-rich peptides. The aim of this work was to evaluate antimicrobial activity of proline-rich peptides, belonging to bactenecins family, against several clinical isolates of drug-resistant Gram-negative bacteria. The bactenecins under examination (ChBac3.4, ChBac5, mini-ChBac7.5Nα, miniChBac7.5Nβ) have been previously found in leukocytes of a domestic goat Capra hircus. We have shown that chemically synthesized analogs of these peptides exhibited a pronounced in vitro antimicrobial activity against Escherichia coli and Acinetobacter baumannii (minimum inhibitory concentrations (MIC) as estimated by a broth microdilution assay varied between 1 to 4 µM) and, to a lesser degree, against Pseudomonas aeruginosa and Klebsiella pneumoniae (MIC 2-16 µM). It was revealed that antibacterial activity of these peptides may be increased if applied in combination with some conventional, antibiotics. E.g., synergistic antimicrobial effects against E. coli have been shown for mini-ChBac7.5Nα bactenecin combined with amikacin (minimal fractional inhibitory concentration index (FICI), 0.375), A. baumannii (FICI, 0.5), and K. pneumoniae (FICI, 0.325), and, using ofloxacin, towards K. pneumoniae (FICI 0.5). Lack of hemolytic activity towards human red blood cells is an important benefit of the studied peptides when used at concentrations several times higher than those showing antimicrobial effects. The data obtained presume certain prospects for further investigations of proline-rich peptides, as well as their structural modifications, for the development of new combined drugs based on these compounds, in order to combat antibiotic-resistant microorganisms, e.g., medications for local applications, various components of medical devices, in particular, venous catheters, stents and wound dressings