Viability of Bacteriophages in the Complex Hydrogel Wound Dressings in vitro.

Using bacteriophages to overcome the increasing resistance of microorganisms to antibiotics is a novel research venue of clinical importance. Among other challenges, this technique is expected to create and maintain an adequate local concentration of bacteriophages at the site of application. In addition, the possibility of combining the phage preparation with antioxidants and anesthetics may provide new options for stimulating the reparative process. The aim of the study was to assess the viability and lytic activity of bacteriophages incorporated into a hydrogel-based wound dressing that contains polyvinyl alcohol, phosphate buffer, with optional additions of succinic acid and lidocaine. Materials and Methods: A technique for incorporating bacteriophages into the complex hydrogel wound dressing ex tempore has been proposed. The bacteriolytic activity of phages inside the hydrogel was determined using standard microbiological techniques. Specifically, we used nutrient media with lawn cultures of Staphylococcus aureus added with the following antibacterial combinations: bacteriophages + succinic acid, bacteriophages + lidocaine, and bacteriophages + succinic acid + lidocaine. The lytic activity of bacteriophages was assessed within 1 to 7 days after the formation of the hydrogel. Results: In all samples containing bacteriophages, the presence of viable and lytically active phages was noted within 1 to 7 days, as evidenced by the "negative colonies" on the culture lawns. On days 1 to 3, no secondary growth was recorded in the phage-containing samples. In hydrogel samples containing phages, succinic acid, and lidocaine, secondary bacterial colonies were detected starting from day 4 indicating some reduction in the lytic activity. Conclusion: The results suggest that bacteriophages immobilized in the hydrogel maintain their viability and lytic activity, and this activity persists when the phages are combined with succinic acid and lidocaine.

[International register "Analysis of Chronic Non-infectious Diseases Dynamics After COVID-19 Infection in Adult Patients (ACTIV SARS-CoV-2)"].

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Regression Models Predicting the Number of Deaths from the New Coronavirus Infection.

Predicting the development of epidemic infection caused by the COVID-19 coronavirus is a matter of the utmost urgency for health care and effective anti-epidemic measures. Given the rapidly changing initial information and the ambiguous quality of data coming from various sources, it is important to quickly optimize the existing prognostic models by using more sophisticated algorithms. The aim of the study is to test the originally developed mathematical algorithms for predicting the development of the COVID-19 epidemic process. MATERIALS AND METHODS: To assess the situation in China, Italy, and the USA, we used the information from Russian- and English-language sources available in official websites. The generally accepted descriptive statistics were used; mathematical modeling was based on linear regression. Statistical data processing was performed using the IBM SPSS Statistics 24.0 and R (RStudio) 3.6.0. RESULTS: We found significant differences not only in the incidence rate of COVID-19 in the countries in question, but also in the death rate. The risk of death associated with COVID-19 is high due to the high number of severe clinical cases of the disease reported from these countries.Two preliminary regression models were created. The first, initial model was based on the increase in new cases of infection - this factor was significantly associated with the outcome; the regression coefficient was 0.02 (95% CI 0.01-0.03). In the second, expanded model, in addition to the increase in new cases, the increase in the number of severe forms of infection was also considered; the regression coefficients were 0.017 (95% CI 0.012-0.022) and 0.01 (95% CI 0.008-0.011), respectively. Adding the second variable contributed to a more accurate description of the available data by the model. CONCLUSION: The developed regression models for infection control and predicting the number of lethal outcomes can be successfully used under conditions of spreading diseases from the group of "new infections" when primary data received from various sourced are changing rapidly and updates of the information are continually required. In addition, our initial model can produce a preliminary assessment of the situation, and the expanded model can increase the accuracy and improve the analytic algorithm.

[Structural Polymorphism of Genome Islands Encoding Resistance to Beta-Lactams in Coagulase-Negative Staphylococci Isolated at Hospitals of the Russian Federation].

Coagulase-negative staphylococci (CoNS) are considered as a reservoir of mobile genetic elements and first of all of the staphylococcal cassette chromosome mec (SCCmec), defining staphylococci resistance to beta-lactams. Types II, IV, IVa, V, VII and VIII SCCmec were detected among 95 staphylococcal strains isolated in different regions of the Russian Federation. Subtypes C1a, C1b, C1c and C1 SCCmec were also identified (class B mec complex and two complexes of ccr1 and ccr2 genes recombinases). Some other cassette types carrying A, C1 and C2 classes of the mec complexes in combination with various recombinase genes were detected. The S.epidermidis isolates mainly formed cassettes carrying mec complex B, while the S. haemolyticus isolates had cassettes carrying classes C1 and C2 mec complex. Out of 9 isolates of S. hominis 5 isolates carried a new type cassette: class A mec complex in combination with the complex of the recombinase ccr1 genes. SCCmec was not identified in S. capitis and S. pasteuri. Their representatives carried either mec complex (1 isolate of S. pasteuri) or the recombinase complexes (2 isolates of S. capitis). The detected SCCmec variants in CoNS could be a source of emergence of new genetic lines of MRSA.

[The mode of detection of microorganisms' sensitivity to disinfectants].

The article presents the technique to evaluate the sensitivity of microorganisms-causative agents of infections isolated from patients, carriers and environment to the disinfectants. The proposed technique gives a possibility to detect the condition of microorganism resistance to disinfectant and to evaluate the degree of its sensitivity. The evaluation of sensitivity specificity accuracy, positive and negative prognostic value, reproducibility of developed technique was made.

[Terminologic aspects of infections associated with administration of medical aid].

Evolution of key terms used in epidemiology of nosocomial infections is discussed. A modern point of view on terminology and comparison of Russian terms with foreign analogues are presented.

[Estimation of species diversity of coagulase-negative staphylococci isolated in hospitals of Russian Federation in 2009-2010].

AIM: Comparative analysis of species diversity of sample of coagulase-negative staphylococci (CNS) isolated in hospitals of different specializations. MATERIALS AND METHODS: For identification of 102 CNS strains, biochemical systems manufactured by NPO "Diagnostic Systems", VITEK 2 Compact, and BBL Crystal as well as sequencing of fragments of tuf and gap genes were used. RESULTS: Greater differentiating capability of genotyping compared with phenotyping methods for species identification of staphylococci was demonstrated. Six CNS species were identified in the sample: S. epidermidis, S. haemolyticus, S. hominis, S. warneri, S. capitis, and S. pasteuri. The largest species diversity was noted for strains from maternity hospitals in Nizhny Novgorod and Kulakov Scientific Center for Obstetrics, Gynecology and Perinatology. Strains isolated from blood of patients in Bakulev Center for Cardiovascular Surgery were represented mostly by S. epidermidis and S. haemolyticus. Differences in species diversity of CNS--causative agents of neonatal conjunctivitis and omphalitis--were observed. CONCLUSION: Two species of CNS: S. epidermidis and S. haemolyticus pose special threat as nosocomial pathogens both in hospitals for adults and obstetrical facilities. Additionally, in neonatal units it is necessary to control such species as S. warneri, S. capitis, S. pasteuri.

[Epidemiological surveillance of nosocomial pyo-septic infections]. / Epidemiologicheskii nadzor za gospital'nymi gnoino-septicheskimi infektsiiami.

The paper analyzes the parameters of epidemiological surveillance of nosocomial pyoseptic infections (NPSI) at surgical hospitals. It considers its basic concepts and presents the authors own findings. Particular emphasis is laid on guidelines for detecting NPSI cases and on epidemiological surveillance. A method of a follow-up is proposed to solve problems in the informational and analytical support of surveillance.

[Prospective observation of pyo-septic infections in frame of epidemiologic surveillance]. / Prospektivnoe nabliudenie v sisteme épidemiologicheskogo nadzora za gospital'nymi gnoino-septicheskimi infektsiiami.

The main principles of prospective observation in cardiosurgical hospitals have been worked out. The method of dynamic observation on hospital pyo-septic infections (HPSI) has shown its high effectiveness and permitted the more complete and timely detection of morbidity, as well as the determination of the groups and factors of risk. In the process of prospective observation and the timely realization of epidemic control measures a considerable decrease in HPSI morbidity has been achieved.

[Epidemiologic features of hospital pyo-septic infection in a cardiosurgical hospital]. / Epidemiologicheskie osobennosti gospital'noi gnoino-septicheskoi infektsii v kardiokhirurgicheskom statsionare.

The results of the epidemiological analysis of morbidity in purulent septic infection in a cardiosurgical hospital during the period of 1990-1963 is presented. As revealed by this analysis, until 1993 the dominating causative agent of this infection was Pseudomonas aeruginosa O16, and since 1994 Staphylococcus epidermidis prevailed. The morbidity dynamics for several years and during individual years is shown. The main risk factors were established. The reanimation department was found to be the main areas where the contamination of patients occurred.