Causative Agents Of Infectious Diseases Research Articles

Detection of Bartonella henselae in feline erythrocytes in Egypt by using Giemsa staining, transmission electron microscopy, and polymerase chain reaction.

Bartonella species (Bartonella spp.) have gained recognition as a significant human pathogen, implicated in a wide range of diseases. Among these, Bartonella henselae infection has been extensively studied for its primary occurrence in cats and its role in the development of cat-scratch disease in humans. While light microscopy and transmission electron microscopy (TEM) have traditionally played crucial roles in identifying causative agents of infectious diseases, including Bartonella spp., the accuracy of these methods in identifying Bartonella spp. remains undefined. Therefore, this study aims to bridge this gap by employing both light microscopy and TEM to detect Bartonella in feline blood samples and to confirm B. henselae with polymerase chain reaction (PCR). Examination of blood smears stained with Giemsa and toluidine blue semithin sections by using light microscopy revealed the presence of intraerythrocytic corpuscles, suggesting Bartonella infection in six out of 33 examined cat blood samples. TEM findings corroborated these observations, showcasing the engulfment of bacteria by the erythrocyte membrane, along with the presence of some Bartonella spp., adhering to the erythrocyte wall. PCR-based molecular detection confirmed the presence of B. henselae in these six samples. It is concluded that light microscopy and TEM are considered valuable in the screening of cats' blood for the potential presence of Bartonella. However, further molecular techniques are essential for precise identification and confirmation of specific Bartonella spp. RESEARCH HIGHLIGHTS: Giemsa-stained blood smear and semithin section showed potential intraerythrocytic Bartonella spp. corpuscles. TEM demonstrated the engulfment of Bartonella spp. by the erythrocyte membrane, along with the presence of some Bartonella spp. adhering to the erythrocyte wall. Molecular analysis of blood samples from cats by PCR unveiled that six out of 33 (18.18%) samples tested positive for B. henselae infection.

Nanomaterials in Drug Delivery: Strengths and Opportunities in Medicine.

There is a myriad of diseases that plague the world ranging from infectious, cancer and other chronic diseases with varying interventions. However, the dynamism of causative agents of infectious diseases and incessant mutations accompanying other forms of chronic diseases like cancer, have worsened the treatment outcomes. These factors often lead to treatment failure via different drug resistance mechanisms. More so, the cost of developing newer drugs is huge. This underscores the need for a paradigm shift in the drug delivery approach in order to achieve desired treatment outcomes. There is intensified research in nanomedicine, which has shown promises in improving the therapeutic outcome of drugs at preclinical stages with increased efficacy and reduced toxicity. Regardless of the huge benefits of nanotechnology in drug delivery, challenges such as regulatory approval, scalability, cost implication and potential toxicity must be addressed via streamlining of regulatory hurdles and increased research funding. In conclusion, the idea of nanotechnology in drug delivery holds immense promise for optimizing therapeutic outcomes. This work presents opportunities to revolutionize treatment strategies, providing expert opinions on translating the huge amount of research in nanomedicine into clinical benefits for patients with resistant infections and cancer.

Neurotropic enteroviruses (Picornaviridae: Enterovirus): predominant types, basis of neurovirulence.

Enteroviruses are one of the most common causative agents of infectious diseases of the central nervous system. They are characterized by genetic variability, the ability to infect a wide range of cells, including brain microglial cells and astrocytes, and persist in the central nervous system tissue, causing delayed and chronic diseases. The review presents data on the basis of neurovirulence of non-polio enteroviruses and the most common pathogens causing enteroviral neuroinfections.

Regulation of σB-Dependent Biofilm Formation in Staphylococcus aureus through Strain-Specific Signaling Induced by Diosgenin.

Staphylococcus aureus is a commensal skin bacterium and a causative agent of infectious diseases. Biofilm formation in S. aureus is a mechanism that facilitates the emergence of resistant strains. This study proposes a mechanism for the regulation of biofilm formation in S. aureus through strain-specific physiological changes induced by the plant steroid diosgenin. A comparison of diosgenin-induced changes in the expression of regulatory genes associated with physiological changes revealed the intracellular regulatory mechanisms involved in biofilm formation. Diosgenin reduced biofilm formation in S. aureus ATCC 6538 and methicillin-resistant S. aureus (MRSA) CCARM 3090 by 39% and 61%, respectively. Conversely, it increased biofilm formation in S. aureus ATCC 29213 and MRSA CCARM 3820 by 186% and 582%, respectively. Cell surface hydrophobicity and extracellular protein and carbohydrate contents changed in a strain-specific manner in response to biofilm formation. An assessment of the changes in gene expression associated with biofilm formation revealed that diosgenin treatment decreased the expression of icaA and spa and increased the expression of RNAIII, agrA, sarA, and sigB in S. aureus ATCC 6538 and MRSA CCARM 3090; however, contrasting gene expression changes were noted in S. aureus ATCC 29213 and MRSA CCARM 3820. These results suggest that a regulatory mechanism of biofilm formation is that activated sigB expression sequentially increases the expression of sarA, agrA, and RNAIII. This increased RNAIII expression decreases the expression of spa, a surface-associated adhesion factor. An additional regulatory mechanism of biofilm formation is that activated sigB expression decreases the expression of an unknown regulator that increases the expression of icaA. This in turn decreases the expression of icaA, which decreases the synthesis of polysaccharide intercellular adhesins and ultimately inhibits biofilm formation. By assessing strain-specific contrasting regulatory signals induced by diosgenin in S. aureus without gene mutation, this study elucidated the signal transduction mechanisms that regulate biofilm formation based on physiological and gene expression changes.

Modern approaches in the diagnosis of avian Pasteurellosis

Studies carried out in many countries of the world demonstrate considerable variability in the virulence properties of pasteurellosis. The variety of antigenicity and toxicity serovars of the pathogen determines a number of specific features of display of poultry pasteurellosis, especially in associated infections when several causative agents of infectious diseases of bacterial and/or viral etiology circulate in one farm. In mixed infections, birds show a variety of clinical signs, most notably a respiratory syndrome characterized by respiratory involvement (sinusitis, conjunctivitis, laryngitis, tracheitis, bronchitis, pneumonia, and aerosacculitis) and tissue swelling in the suborbital sinuses, intermandibular spaces, and ear flaps.This situation makes it difficult to timely and promptly conduct effective therapeutic and anti-epizootic measures. However, it is necessary to identify the etiology of the disease as soon as possible, methodically and comprehensively, taking into account epizootic data, clinical signs, pathological anatomical changes and with obligatory confirmation by laboratory tests.At present time laboratory methods for diagnostics of avian pasteurellosis are regulated by Methodical instructions (MI) on laboratory diagnostics of pasteurellosis of animals and birds approved by the Chief Veterinary Department on August 20, 1992 № 22-7/82.According to the approved MI, the laboratory diagnosis of avian pasteurellosis includes microscopy of smears and fingerprints, isolation of pasteurella cultures and their identification, and, if necessary, bioassaying.It should be noted that the laboratory diagnosis of pasteurellosis according to the MI is a laborious and time-consuming process.Apart from the methods described in the MI, the serological method - enzyme immunoassay (ELISA) and molecular biological method - polymerase chain reaction (PCR) are currently widely and successfully used in laboratory practice for diagnosis of avian pasteurellosis, which are not reflected in the approved MI, but allow relatively simple and rapid reliable results.

CHANGES IN ADHESIVE PROPERTIES OF CLINICAL ISOLATES OF STREPTOCOCCUS MITIS AFTER EXPOSURE TO ANTISEPTICS

The resident oral microbiota plays an important role as a factor in its colonization resistance that ensures human oral health. However, at the same time, oral microorganisms can act as causative agents of infectious diseases. Scientists emphasize that in the situation when bacteria demonstrated increased resistance to antibiotics, quorum sensing is a particularly attractive target, since this mechanism controls several factors of bacterial virulence that affect adhesion, invasion and colonization of microorganisms during the development of the pathological process. Quorum sensing inhibitors can be enzymes and various chemicals that able to affect quorum sensing. Streptococcus mitis is a representative of the resident microbiota of the human oropharynx. But despite its commensalism, Streptococcus mitis in association with other microorganisms takes part in many pathological processes. Objective of this study is to study the effect of Dekasan and Iodoform antiseptics on the adhesive properties of Streptococus mitis clinical isolates taken from the oral cavity of patients with infectious and inflammatory post-extraction complications.
 Materials and methods: examined clinical isolates of Streptococus mitis, which were isolated from 8 patients undergoing treatment for infectious-inflammatory post-extraction complications in the medical and surgical department of Poltava Regional Centre of Stomatology - Dental Clinical Polyclinic. Identification of selected cultures was carried out using an automatic bacteriological analyzer Vitec-2 compact bioMarieux (France). We used the average values of subbacteriostatic concentrations of the active ingredients of antiseptics. Adhesive properties of clinical isolates under the influence of Dekasan and Iodoform were determined according to the method of V.I. Brylis.
 Conclusions: antiseptics have different effects on the adhesive properties of clinical isolates of Streptococus mitis.

Modulating macrophage function to reinforce host innate resistance against Mycobacterium avium complex infection.

Mycobacterium avium complex (MAC) is the main causative agent of infectious diseases in humans among nontuberculous mycobacteria (NTM) that are ubiquitous organisms found in environmental media such as soil as well as in domestic and natural waters. MAC is a primary causative agent of NTM-lung disease that threaten immunocompromised or structural lung disease patients. The incidence and the prevalence of M. tuberculosis infection have been reduced, while MAC infections and mortality rates have increased, making it a cause of global health concern. The emergence of drug resistance and the side effects of long-term drug use have led to a poor outcome of treatment regimens against MAC infections. Therefore, the development of host-directed therapy (HDT) has recently gained interest, aiming to accelerate mycobacterial clearance and reversing lung damage by employing the immune system using a novel adjuvant strategy to improve the clinical outcome of MAC infection. Therefore, in this review, we discuss the innate immune responses that contribute to MAC infection focusing on macrophages, chief innate immune cells, and host susceptibility factors in patients. We also discuss potential HDTs that can act on the signaling pathway of macrophages, thereby contributing to antimycobacterial activity as a part of the innate immune response during MAC infection. Furthermore, this review provides new insights into MAC infection control that modulates and enhances macrophage function, promoting host antimicrobial activity in response to potential HDTs and thus presenting a deeper understanding of the interactions between macrophages and MACs during infection.

Advanced nano biosensorsfor rapid detection of zoonotic bacteria.

An infectious disease that is transmitted from animals to humans and vice-versa is called zoonosis. Bacterial zoonotic diseases can re-emerge after they have been eradicated or controlled and are among the world's major health problems which inflict tremendous burden on healthcare systems. The first step to encounter such illnesses can be early and precise detection of bacterial pathogens to further prevent the following losses due to their infections. Although conventional methods for diagnosing pathogens, including culture-based, polymerase chain reaction-based, and immunological-based techniques, benefit from their advantages, they also have their own drawbacks, for example, taking long time to provide results, and requiring laborious work, expensive materials, and special equipment in certain conditions. Consequently, there is a greater tendency to introduce simple, innovative, quicker, accurate, and low-cost detection methods to effectively characterize the causative agents of infectious diseases. Biosensors, therefore, seem to practically be one of those novel promising diagnostic tools on this aim. These are effective and reliable elements with high sensitivity and specificity, that their usability can even be improved in medical diagnostic systems when empowered by nanoparticles. In the present review, recent advances in the development of several bio and nano biosensors, for rapid detection of zoonotic bacteria, have been discussed in details.

Metagenomic characterization of bacterial community and antibiotic resistance genes found in the mass transit system in Seoul, South Korea

Mass transit systems, including subways and buses, are useful environments for studying the urban microbiome, as the vast majority of populations in urban areas use public transportation. Microbial communities in urban environments include both human- and environment-associated bacteria that play roles in health and pathogen transmission. In this study, we used shotgun metagenomic sequencing to profile microbial communities sampled from various surfaces found in subway stations and bus stops within the Seoul mass transit system. The metagenomic approach and network analysis were used to investigate broad-spectrum antibiotic resistance genes (ARGs) and their co-occurrence patterns. We uncovered 598 bacterial species in 76 samples collected from various surfaces within the Seoul mass transit system. All samples were dominated by the potential human pathogen Salmonella enterica (40 %) and the human skin bacterium Cutibacterium acnes (19 %). Significantly abundant biomarkers detected in subway station samples were associated with bacteria typically found in the human oral cavity and respiratory tract, whereas biomarkers detected in bus stop samples were associated with bacteria commonly found in soil, water, and plants. Temperature and location had significant effects on microbial community structure and diversity. In total, 41 unique ARG subtypes were identified, associated with single-drug or multidrug resistance to clinically important and extensively used antibiotics, including aminoglycosides, carbapenem, glycopeptide, and sulfonamides. We revealed that Seoul subway stations and bus stops possess unique microbiomes containing potential human pathogens and ARGs. These findings provide insights for refining location-specific responses to reduce exposure to potentially causative agents of infectious diseases, improving public health.

Antimicrobial Activity of Lactic Acid Bacteria (Lab) Isolated from Yoghurt and Fish against Pathogenic Bacteria Isolated from Fish in Ethiopia

Pathogenic bacteria are causative agent of infectious diseases in fish. Antimicrobials are widely applied in fish products for prevention of fish-borne diseases. The global concern of antimicrobial resistance of bacteria raises attentiveness of the different ways of using antimicrobial peptides (AMPs). The aim of the present study was to detect the antimicrobial activity of the AMPs from Lactic acid bacteria (LAB) against the growth of pathogenic bacteria isolated from fish in Ethiopia. Cell Free Supernatants (CFSs) from 4 strains of LAB consisting of lactobacillus paracasei sub.paracasei, lactobacillus casei LC2W, Pediococcus acidilactici and lactobacillus plantarum were tested against pathogenic bacteria of Aeromonas hydrophila, Aeromonas veronii, Edwardsiella tarda, Escherichia coli, Proteus mirabilis, Pseudomonas fluorescens and Shigella flexneri via using agar well diffusion assay. All tested CFSs revealed antimicrobial activity against the tested fish pathogenic isolates at different extents. CFSs of lactobacillus plantarum, Lb. casei LC2W and lactobacillus paracasei sub.paracasei showed strong antibacterial activity against Edwardsiella tarda (19 mm), Aeromonas hydrophila (18 mm) and Pseudomonas fluorescens (18 mm) respectively, with the well diffusion assay. The study shows the antimicrobial activity of the 4 strains of LAB CFSs against the bacterial fish pathogens and indicates the application opportunities as fish product bio preservative.

Animal health

According to some definitions health is the absence of disease, thus it can be said that disease is the lack of health. However, it is difficult to agree with such a simplified approach, as health is not just a synonym for health status. The term health status has a much wider implication and it implies not only the state of health i.e. if the animals are healthy or not, but also is the herd is free from infectious diseases, and the implementation of biotechnological measures for the maintenance of productivity. It is possible that the animals have a poor health status (presence of latent infections) but are clinically healthy and productive. Similarly, it is possible that the animals are in a good health status, but the management, housing, care and diet are not adequate, resulting in the manifestation of clinical signs of disease. A disease is essentially the absence of health, i.e. a deviation from the harmonious functioning of some organs or organisms, which can then be clearly manifested through certain symptoms or signs, which is also called the clinical form of the disease. However, very often some diseases are present in a subclinical or latent form, when they can only be detected by one of the methods of serodiagnosis, but the best and safest way is by identifying the cause or by considering some parameters that indicate a decline in production. Health is a prerequisite for the profitability of keeping and raising animals. A healthy animal produces a healthy product that, after processing, becomes food for humans. In this way, human health is also protected. Animal proteins are an indispensable nutrient in the diet of the population. Unfortunately, animal health does not depend only on measures implemented in an area, country, or even a continent, but on a wider, global space and mode of transmission, most often of the causative agents of infectious diseases, which cause enormous damage to the economies of countries relaying on animal husbandry. Under the patronage of world organizations, the World Health Organization (WHO), the Food and Agriculture Organization (FAO) and the World Organization for Animal Health (OIE), of which almost all countries are members, universal rules and guidelines are being prepared and adopted for monitoring, detection, prevention of spreading, and control and eradication animal diseases. Each country adopts health care programs according to its potentials and accepts the obligation to report to world organizations, primarily to OIE, in the event of certain diseases of terrestrial and aquatic animals. Veterinary services have the greatest responsibility for animal health and food of animal origin, they have the role of public service in the protection of public health. Some countries have declared veterinary activity a common good, and the initiative is to define this service on a global scale. It is known that there are 1415 pathogens that cause infectious diseases in humans. Over 60% of human infectious diseases are of a zoonotic nature. At least 75% of emerging infectious diseases in humans are of animal origin. Every year, five new infectious diseases in humans appear, and most of them are of animal origin. Out of the pathogens with potential use for bioterrorist purposes, 80% of them are zoonotic pathogens. Disease prevention (preventive health care) will be a priority for veterinary and health systems and services in the future. In addition to the immunological measures that are being implemented (vaccination), epidemiological services have a wide range of options at their disposal that will become more important. Veterinary medicine works very effectively on the protection of farm breeding of various species of animals by prescribing the consistent application of health, zoohygiene and biosafety measures and procedures. In that way, the contact of the causative agent of the disease with the animal is prevented, which has proven to be the key factor in preventing the occurrence of mass diseases (epidemics, pandemics and other forms of infectious diseases).

Ultrastructure and Morphological Variability of Non-Culturable Forms of Yersinia pseudotuberculosis Bacteria.

One of the mechanisms underlying the appearance of chronic infections is transition of pathogens into a non-culturable state, which is largely associated with the use of antibiotics. We studied ultrastructure of dormant bacteria Yersinia pseudotuberculosis obtained from the vegetative form of strain 512 by inhibition with kanamycin. On the model of the causative agent of pseudotuberculosis we showed that transition of prokaryotes to a dormant state occurs through apoptosis of bacteria. Fragmentation and condensation of chromatin with the formation of electron-dense fibrils, clumps and large conglomerates characteristic of apoptosis were found in the nucleoid zone of the cytoplasm of inhibited bacterial cells. These results are of great importance for understanding the mechanisms of the existence of pathogens in different conditions, as well as for identifying the causative agents of infectious diseases.

Microbiological features of the salt lakes of the Kulunda lake system

The object of the study was the water and bottom sediments of the Bolshoye Yarovoye and Burlinskoye salt lakes located in the Kulunda steppe lowland and having recreational value. The aim of this work is to study the antibacterial and anti-candidiasis properties of water and bottom sediments of lakes in the Kulunda lake region in the context of their ecological state. The main factors affecting the basins of lakes B. Yarovoe and Burlinskoe are the intensification of the recreational load due to the development of domestic tourism, the activities of industrial enterprises, and, as a consequence, the washout of pollutants, the extraction and transportation of salt (in Lake Burlinskoe) and the almost complete extraction of silt mud. (in Lake B. Yarovoe), plowing of adjacent territories. No causative agents of infectious diseases were found in the water and bottom sediments, and the total microbial count is about 102 CFU / ml. The predominant group of microorganisms found on agar culture media are non-spore-bearing bacteria. The water of the salty lake B. Yarovoe, filtered from microorganisms, possesses inhibitory properties in relation to all studied 14 gram-positive and gram-negative test strains of microorganisms, and the water of Lake Burlinskoye in relation to nine strains: gram-negative bacteria Salmonella sonnei 32, Klebsiella pneumonia В-4894, Рseudomonas mirabilis 160205, Serratia marcescens d, Pseudomonas aeruginosa ATCC 9027, Escherichia coli 6645 ATCC 25922, gram-positive bacteria Staphylococcus aureus ATCC 6538, Mycobacterium smegmatis GK and regarding the causative agent of candidiasis Candida albicans 620. It was also shown that pure cultures of spore-forming bacteria isolated from the water and bottom sediments of the studied lakes also have antagonistic activity. The ecological stability of lake ecosystems, in spite of anthropogenic transformation and climatic changes affecting the water and salt regime, is based on biogenic processes that provide resistance to microorganisms introduced from outside, including pathogenic ones, and their elimination.

Influence of Genetic Factors on Immunopathogenesis and Clinical Phenotypes of ANCA-associated Vasculitis

The review presents the recent data on assumed risk factors for the development of ANCA-associated vasculitis (AAV), among which environmental factors, such as climatic, chemical, etc., are of particular interest of researchers. Controversial opinions of various authors on the role of individual causative agents of infectious diseases in the development of AAV are analyzed. The review pays special attention to scientific data on the influence of variants of the structure of genes encoding various components of the immune system on the development of the pathogenetic process of AAV. Up-to-date information on the association of single-nucleotide polymorphisms (SNPs) with the course, risk of development and the likelihood of AAV recurrence is indicated, the most associated of which are genes encoding proteins of the main histocompatibility complex (HLA), a toll-like receptors (TLR`s), as well as an inhibitor of serine proteinases-alpha-antitrypsin (AAT). The analysis of scientific publications describing the molecular mechanism of the development of a pathological focus that forms the conditions for the synthesis of PR3ANCA and MPOANCA complexes characteristic of AAV has been carried out. The data of a number of foreign studies on the relationship of individual SNPs associated with the features of the course of granulomatosis with polyangiitis, microscopic polyangiitis, as well as eosinophilic granulomatosis with polyangiitis are presented and summarized. The review presents current AAV treatment regimens and promising directions for the development of medical care for patients.

Antibacterial Resistance Pattern in Clinical and Non-clinical Bacteria by Phenotypic and Genotypic Assessment

Bacterial infections represent a very serious problem that threatens human health, antibiotics were designed to attack the causative agents of infectious diseases, but some bacterial pathogens became virulent and resistant to antibiotics by different mechanisms, resistance genes represented one of those mechanisms. This study attempts to screen the existence of five different resistance genes (mecA, TEM, FemA, MexD, and AmpC) among 25 bacterial isolates divided into two groups the first was non-clinical bacterial type strains including Bacillus subtilis, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Salmonella typhi, and the other group includes some clinical bacterial isolates. Evaluation of their susceptibilities to different 12 antibiotic discs and attempting to find the relationship between genotype and phenotype assessment. Different responses were reported which varied from slightly susceptible to multidrug-resistant such as P. aeruginosa and K. pneumonia which could be considered as multidrug-resistant strains. Therefore, detection of resistance gene became crucial and critical to recognize the mechanism of resistance, five pairs of primers were included to investigate five responsible genes belonging to beta-lactamases, efflux pump, and methicillin resistance. Conclusively, the PCR technique is a very accurate tool to check the genetic resistance whether being expressed to phenotype or not. Moreover, the clinical bacterial isolates appeared more resistant that reflecting the impact of the surrounding environment on bacterial behavior.

Natural Products Homoharringtonine and Emetine Alkaloids as SARS-CoV-2 Treatment Options

Viruses are known as the major causative agents for infectious diseases globally. The coronaviruses are one of the serious pathogens to cause serious diseases in humans. Recently identified SARSCoV- 2 from Wuhan City, China, has emerged as a serious threat to human health and caused a global pandemic. Bats have been confirmed as a primary source of infection. The vaccination of the human population and animals serving as a potential reservoir is a straightforward strategy to control the transmission of any pathogen to humans. Natural products from many herbal plants are well known to have novel antiviral properties and evaluated against various viral diseases. There are many alkaloids that have shown to be effective against coronaviruses. Recently, the antiviral efficacy of natural alkaloids known as Homoharringtonine (HTT) and Emetine has been evaluated and provided promising results against coronaviruses, including SARS-CoVs. These alkaloids may be very useful and can be used as antivirals against SARS-CoV-2 because they have already been reported to inhibit the replication of SASRS-CoV and other viruses in cell lines. This review specifically focuses on the recent findings of these alkaloids against coronaviruses and possible treatment options for SARS-CoV-2. It is expected that natural products as alkaloids from herbal plants could be considered as novel and valuable candidates for the new antiviral drugs against SARS-CoV-2.

Изучение восприимчивости возбудителей стафилококкоза, стрептококкоза к лекарственным препаратам

The article gives consideration to the determination of the susceptibility of causative agents of staphylococcosis and streptococcosis to antibiotics. Long-term use of medicinal preparations, including antibiotics, leads to the emergence of generations of microorganisms that are resistant to causative agents of infectious diseases, and this is the reason for the decrease in the effectiveness of medical and preventive measures. Considering all this, the susceptibility degree of cultures of causative agents of staphylococcosis and streptococcosis to drugs such as enroline, colistin, gentamicin, tilazine, furazalidone and neomycin was studied. The susceptibility of Staphylococcus pyugenes cultures to enroline, gentamicin and colistin by 22.2%, and to furasilidone by 74.0%, and Streptococcus feccalus cultures by 38.0% to enolin, by 33.3% to gentamicin, by 19.0% to colistin and by 33.3% to furazalidone were investigated. On the basis of findings of investigations, the highest sensitivity of Staphylococcus pyugenes to furazalidone by 74.0% was revealed. And from the preparations we studied, it was found that Streptococcus feccalus is susceptible to enroline by 38.0%.

Антибиотикорезистентность как фактор вирулентности условно-патогенных микроорганизмов

Introduction: A large number of infectious processes are associated with opportunistic microorganisms. The phenotype of antibiotic resistance of such pathogens is multidrug-resistant strains with the presence of various β-lactamases. Our objective was to determine the phenotypic and genotypic features of antibiotic resistance of staphylococci, enterobacteria, and non-fermenting Gram-negative bacteria – the cause of infectious diseases in patients of various health facilities of Nizhny Novgorod. Material and methods : Using classical microbiological methods and molecular genetic studies, we analyzed 486 strains of microorganisms isolated from the upper respiratory tract, intestines, urine, and wound discharge of patients in 2019–2020. In all isolates, the phenotype of antibiotic resistance was determined by the disco-diffusion method (Bioanalyse, Turkey) and using the Multiscan FC spectrophotometer (ThermoScientific, Finland) with Microlatest tablets (PLIVA-Lachema, Czech Republic), along with molecular features of resistance mechanisms by PCR on the CFX96 device (BioRad, USA) using AmpliSens kits (Russia). Results and discussion : The results showed that the most prevalent causative agents of infectious diseases (40.7 %) were Gram-negative bacteria, of which Enterobacteriaceae and non-fermenting bacteria accounted for 27.1 % and 13.6 % of cases, respectively. Staphylococci were isolated in 37.6 % of patients: S. aureus and coagulase-negative staphylococci induced 13.4 % and 24.2 % of cases, respectively. The analysis of antibiotic resistance of the isolates showed a high level of antimicrobial resistance in all hospitals, regardless of the isolation locus. The phenotype of methicillin-resistant strains was found in 26.3 % and 37.9 % of S. aureus and coagulase-negative staphylococci, respectively; the mecA gene was found in 89.0 % of methicillin-resistant staphylococci. The highest number of antibiotic-resistant strains among Gram-negative microorganisms was observed in K. pneumoniae , A. baumannii , and P. aeruginosa . We established that 61.7 % of K. pneumoniae , 75.1 % of A. baumannii , and 58.2 % of P. aeruginosa were resistant to carbapenems. The results of molecular genetic studies confirmed the presence of serine carbapenemases KPC and OXA groups in all multidrug-resistant K. pneumoniae and A. baumannii ; genes of the metallo-β-lactamase of VIM group were found in 40.9 % strains of P. aeruginosa . The production of numerous β-lactamases and the presence of determinants of antibiotic resistance in the genome determine the virulent properties of opportunistic microorganisms. Conclusion: The antibiotic resistance of opportunistic microorganisms is the cause of developing a chronic infectious process. Today, a wide spread of antibiotic-resistant infectious agents is a serious public health problem, which determines the need for constant microbiological monitoring and studies of molecular mechanisms of resistance to identify the most potent antibiotics and to determine the ways of eradication of multidrug-resistant strains.

Antibiotic Resistance as a Virulence Factor of Opportunistic Microorganisms

Introduction: A large number of infectious processes are associated with opportunistic microorganisms. The phenotype of antibiotic resistance of such pathogens is multidrug-resistant strains with the presence of various β-lactamases. Our objective was to determine the phenotypic and genotypic features of antibiotic resistance of staphylococci, enterobacteria, and non-fermenting Gram-negative bacteria – the cause of infectious diseases in patients of various health facilities of Nizhny Novgorod. Material and methods: Using classical microbiological methods and molecular genetic studies, we analyzed 486 strains of microorganisms isolated from the upper respiratory tract, intestines, urine, and wound discharge of patients in 2019–2020. In all isolates, the phenotype of antibiotic resistance was determined by the disco-diffusion method (Bioanalyse, Turkey) and using the Multiscan FC spectrophotometer (ThermoScientific, Finland) with Microlatest tablets (PLIVA-Lachema, Czech Republic), along with molecular features of resistance mechanisms by PCR on the CFX96 device (BioRad, USA) using AmpliSens kits (Russia). Results and discussion: The results showed that the most prevalent causative agents of infectious diseases (40.7 %) were Gram-negative bacteria, of which Enterobacteriaceae and non-fermenting bacteria accounted for 27.1 % and 13.6 % of cases, respectively. Staphylococci were isolated in 37.6 % of patients: S. aureus and coagulase-negative staphylococci induced 13.4 % and 24.2 % of cases, respectively. The analysis of antibiotic resistance of the isolates showed a high level of antimicrobial resistance in all hospitals, regardless of the isolation locus. The phenotype of methicillin-resistant strains was found in 26.3 % and 37.9 % of S. aureus and coagulase-negative staphylococci, respectively; the mecA gene was found in 89.0 % of methicillin-resistant staphylococci. The highest number of antibiotic-resistant strains among Gram-negative microorganisms was observed in K. pneumoniae, A. baumannii, and P. aeruginosa. We established that 61.7 % of K. pneumoniae, 75.1 % of A. baumannii, and 58.2 % of P. aeruginosa were resistant to carbapenems. The results of molecular genetic studies confirmed the presence of serine carbapenemases KPC and OXA groups in all multidrug-resistant K. pneumoniae and A. baumannii; genes of the metallo-β-lactamase of VIM group were found in 40.9 % strains of P. aeruginosa. The production of numerous β-lactamases and the presence of determinants of antibiotic resistance in the genome determine the virulent properties of opportunistic microorganisms. Conclusion: The antibiotic resistance of opportunistic microorganisms is the cause of developing a chronic infectious process. Today, a wide spread of antibiotic-resistant infectious agents is a serious public health problem, which determines the need for constant microbiological monitoring and studies of molecular mechanisms of resistance to identify the most potent antibiotics and to determine the ways of eradication of multidrug-resistant strains.

The Relationship Between Microbiology as a Science and the Microbiology Subject

From ancient times to the Renaissance, science constitutes a knowledge that is based on the contemplation of nature. The use of the preceding results, their permanent modification, the crossing of information, models, is what constitutes science, in a cumulative tradition of knowledge and practices. The objective of this work is to contribute to the knowledge of the history of microbiology and its role in the education and preparation of future doctors. Our knowledge of microbes has had a negative side, since they are the causative agents of infectious diseases, contamination and deterioration of food, materials, etc. After the golden age of Bacteriology, inaugurated by great figures such as Pasteur and Koch, Microbiology remained for some time a descriptive and applied discipline, closely interwoven with Medicine, and with a development parallel to that of Chemistry, which it would contribute several fundamental methodological advances. Our knowledge of microbes has had a negative side, fear, since they are the causative agents of infectious diseases, and of contamination and deterioration of food, materials, etc. However, we are beginning to realize that we are completely dependent on microbial life. Life not only began with prokaryotic microorganisms, but the continuity of the very existence of life on Earth rests with them. The Microbiology subject is essential to understand the functioning of ecosystems and the interactions between the atmospheric, aquatic and terrestrial environment. Our objective is that, after taking the course, the student has acquired a global vision about the microbial world, the impact of microorganisms in the environment and their possible use in technological processes associated with the environment. We emphasize the importance of Microbiology in medicine and other related careers.