Relevance. Despite more than 50 years of successful experience with pertussis immunization, pertussis remains an important public health problem. WHO estimated 16 million people worldwide are infected per year, a significant number of whom are children under 1 year of age. In the last 10 years a significant increase in the incidence of whooping cough has been observed in many countries with a high immunization coverage level. In Russia, specific prevention of whooping cough, is held since 1959. Specific prevention of whooping cough has led to considerable improvement of an epidemiological situation and has shown its social and economic importance for maintenance of sanitary and epidemiologic wellbeing on this infection in Russia. Goal. Study the structure of population B. pertussis circulating in Russia in dynamics of whooping cough epidemic process. Materials and methods Studied 573 B. pertussis strains allocated from patients with whooping cough in 1948 - 2015 used multilocus sequence typing (MAST). Isolates divided in five groups: 1948 - 1969 - 37 strains, isolated in the vaccination period and the first ten years of mass childhood immunization; 1970 - 1989 - 63 strains; 1990 - 2005 - 203 strains (from G.N. Gabrichevsky Institute of Epidemiology and Microbiology collection); 2006 - 2012 - 185 strains; 2013 - 2015 - 85 strains. Genotyping of strains was carried out according to the scheme MAST2 on the basis of a sequence of fragments of genes of ptxP-fim3-prn. Results of sequencing-typing were computed in the CromasLite program, identification of alleles and sequencing types carried out on EMBL/GenBank. Results. Formation of population of B.pertussis strains during more than 50 years went on the way of consecutive change of vaccinal genotype strains with strains of new nonvaccinal genotypes. Conclusions. Modern population of the causative agent of whooping cough is presented by the strains of genotype 322 and 329 possessing high virulence and causing heavier clinical course of disease.
The aim of the study was to characterize toxigenic strains of Corynebacterium diphtheriae by examining 12 toxigenic strains of C.diphtheriae isolated in Russia between January, 2017 to June, 2019. The morphological, toxigenic and biochemical properties of C.diphtheriae was studied. Genotyping of C.diphtheriae strains was performed by using MLST and dtxR gene sequencing with subsequent phylogenetic analysis. Results. Toxigenic strains of C.diphtheriae were isolated in the Novosibirsk, Samara and Chelyabinsk regions, the Khanty-Mansi autonomous okrug - Yugra as well as the republic Northern Ossetia - Alania. Among these strains, 5 of them were isolated from diphtheria patients (moderate disease found in one case, mild course – remaining patients) and 7 strains were isolated from bacterial carriers. In two cases C.diphtheriae from diphtheria patients were identified as ST25 sequence type, gravis variant; in one case – ST8 type, gravis variant; two cases – ST67 sequence type, mitis variant. In asymptomatic carriers of tox-positive C.diphtheriae strains they belonged to ST25 sequence type, gravis variant – in two cases, ST67 type, mitis variant – in four cases. A sequencing type was not identified in one case. All sequence types were widespread globally being presented by a large number of isolates in the PubMLST and characterized by a substantial amount of derivative sequence types. At the same time, they belonged to different clonal complexes and differed markedly from each other contributing to their reliable difference as assessed by MLST. Study of gene dtxR sequence diversity showed that all allelic variants were typical for the representatives of these a sequence types. New alleles of gene dtxR were not revealed in strains examined. It was shown that non-synonymous substitution C440T leading to A147V amino acid substitution was found solely in one allele distributed in ST8, ST185, ST195 and ST451 types suggesting at late mutation. In contrast, the polymorphism C640A resulting in the amino acid substitution L214I was found not only in the same allele, but also in the basal tree branches indicating that isoleucine was in the ancestral sequence of the protein.
Bloodstream infection (BI) is the cause of high mortality. Hospital bloodstream infection (HBI) complicates hemodialysis, pneumonia, oncohematological diseases. Positive hemoculture obtaining depends on the volume of blood inoculation, the number of blood samples, the incubation time. To test the principles of microbiological culturomics in the diagnosis BI of hospital patients with a therapeutic profile. 848 hospital cardiac patients with suspected BI were included. 10 ml of blood were taken intravenously with a syringe, blood was inoculated into 200 ml of the heart-brain medium (HBM) in an anaerobic bottle. It was incubated for 7 or more days in a thermostat at +37º C. The hemocultures were obtained in 64.3% of cases with paired blood sampling with an interval of 30 minutes whereas an increase in the number of blood samples reduced the effectiveness of obtaining hemocultures to 9.1%. When incubating bottles for more than 7 days there were obtained 200 additional hemocultures containing 239 strains of microorganisms. Episodes of HBI were observed more often in the cases of the circulatory system (77.8%), including infectious endocarditis (IE) (47.0%), rheumatism (22.1%), myocarditis (14.6%). Episodes of HBI occurred more often in men with IE and coronary heart disease, in women - with rheumatism and myocarditis. Patients aged 45-75 were in the group of risk with a probability of complications of HBI up to 73.7%. When examining the blood of 848 hospital patients of cardiological profile HBI was detected in 38.3% of cases. Among clinical isolates gram-positive cocci with a great number S.epidermidis prevailed. Polymicrobial hemocultures (16.3%) were characterized by two and three associates in one blood sample. Among the hematological indicators in HBI there were: leukocytosis, increased ESR, lymphocytosis, decreased hemoglobin; increased values of fibrinogen, CRP, γ-globulin, α2-globulin, low levels of total protein and A/G coefficient. The techniques of microbiological culturomics were used. HBI was diagnosed in 38.3% of the therapeutic patients of cardiological profile. The etiology of HBI was characterized by polymicrobicity in 16.3% of cases. Hematological markers of HBI were identified.
The purpose of the work was to assess the state of bacteriological diagnosis of diphtheria infection in Russia in order to establish possible reasons for the decrease in the release of C. diphtheriae. The Reference Center for Monitoring the Pathogens of Measles, Rubella, Mumps, Pertussis and Diphtheria in 2018 in 85 subjects of Russia conducted a questionnaire of laboratories of medical organizations and the Centers for Hygiene and Epidemiology of Rospotrebnadzor, carrying out bacteriological studies for diphtheria infection. It was found that the number of studies conducted over the five-year period decreased by 1.2 times. The tendency to decrease the number of bacteriological studies for diphtheria is observed in the territories of almost all federal districts. In 99% and 29% of cases, the institutions of the FBUZ Centers for Hygiene and Epidemiology and medical organizations (MO) and use in their work documents regulating bacteriological studies for diphtheria infection. In a number of territories, the list of documents used includes documents that are invalid or do not define such studies. Most organizations use dry tampons when examining for diphtheria, however, 13.1% and 53.4% of FBUZ Centers for Hygiene and Epidemiology and medical organizations (respectively) use commercial transport environments, which does not comply with regulatory documentation. Analysis of the quality of work of bacteriological laboratories showed shortcomings at the stage of preparation of media (use of donor blood, or absence of addition of blood and potassium tellurite), Elek tests (addition of horse serum or absence of serum to the medium), setting of incomplete biochemical series (absence of tests for urease and nitrate reductase), absence of standard control strains, incomplete volume of internal laboratory quality control. Given the continuing circulation of the pathogen in various countries of the world and in our country, as well as the possibility of imported cases of infection from endemic regions, the analysis was aimed at drawing the attention of specialists to the problem of improving the quality of laboratory diagnosis of diphtheria in Russia.
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