Epidemiology and Infectious Diseases

BACKGROUND: The primary causative agents of lower urinary tract infections are Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecalis. In recent years, these bacteria have demonstrated high levels of antibiotic resistance. The barrier function of the bladder mucosal epithelium is largely determined by the glycosaminoglycan layer, which protects the bladder wall from infectious agents. Disruption of this layer leads to inflammation, which may progress to painful bladder syndrome or cystitis. Pentosan polysulfate sodium is a semisynthetic glycosaminoglycan that is chemically and structurally similar to naturally occurring glycosaminoglycans. It restores the damaged urothelial layer and prevents contact between the bladder mucosal epithelium and various aggressive substances dissolved in urine.

AIM: This work aimed to investigate the in vitro antibacterial, antiadhesive, and antibiofilm activities of pentosan polysulfate sodium.

METHODS: Classical bacteriological methods, mass spectrometry, microscopy, an experimental adhesion model using buccal epithelial cells, and statistical data analysis were used. Study material was obtained from women aged 18 years and older with a history of cystitis lasting at least three years during disease exacerbation.

RESULTS: The antibacterial effect of pentosan polysulfate sodium during co-cultivation with the main pathogens of lower urinary tract infections persisted for up to 15 hours. The mechanism of antibacterial action was associated with the ability of pentosan polysulfate sodium to inhibit bacterial adhesion to the urothelium. The most pronounced antiadhesive effect was observed against E. faecalis: in the presence of pentosan polysulfate sodium, there was a 3.7-fold decrease in the number of bacteria adhered to buccal epithelial cells. The adhesion index decreased by 3.3-fold for E. coli and 2.6-fold for K. pneumoniae. Pentosan polysulfate sodium also demonstrated antibiofilm properties, reducing the density of biofilms formed by E. coli by 1.7-fold, E. faecalis by 1.6-fold, and K. pneumoniae by 1.2-fold. These findings confirm the potential of pentosan polysulfate sodium to enhance the effectiveness of therapy for lower urinary tract infections, particularly those associated with microbial biofilms.

CONCLUSION: This in vitro study made it possible to identify and quantitatively assess the antibacterial, antiadhesive, and antibiofilm activities of pentosan polysulfate sodium against uropathogenic microorganisms isolated from the urine of patients with recurrent lower urinary tract infections.

BACKGROUND: Community-acquired pneumonia retains high socioeconomic and epidemiologic significance. Investigation of its etiology and antibiotic resistance patterns is of substantial practical importance, particularly in the context of the global epidemiologic threat associated with COVID-19.

AIM: This study aimed to study the etiologic structure and antibiotic resistance of bacteria isolated from the lower respiratory tract of patients with community-acquired pneumonia.

METHODS: This was a single-center, retrospective, uncontrolled study. Medical records of patients diagnosed with community-acquired pneumonia who were hospitalized in the Pulmonology Department of Kazan City Clinical Hospital from January 2018 to December 2021 were analyzed. Susceptibility of bacteria isolated from patients’ sputum to 19 antimicrobial agents was determined using the disk diffusion method.

RESULTS: A total of 282 medical records of patients aged 18–94 years were analyzed. Bacteria and their associations were isolated in 245 patients (86.9% ± 2.01%). In nearly half of the cases (47.9% ± 4.4%), sputum cultures contained Candida albicans, both as a monoculture and in association with bacterial flora. Streptococcus pyogenes was isolated from the sputum of every fifth patient (20.2% ± 5.4%), and Streptococcus pneumonia from every sixth patient (14.2% ± 5.6%). The detection rate of C. albicans was significantly higher than that of other isolates (p < 0.001). During the COVID-19 pandemic, the proportion of Candida albicans increased 1.36-fold in 2020 and 1.84-fold in 2021 compared with 2019. Before the pandemic, gram-positive bacteria predominated in the etiologic structure; however, beginning in 2020, a trend toward an increased proportion of gram-negative microflora was observed. The proportion of gram-negative bacteria increased from 7.14% ± 11.5% to 38.46% ± 21.8%, both in association with fungi and in monoculture. This increase was attributable to Enterobacter agglomerans and Klebsiella pneumoniae.

Analysis of the antimicrobial resistance of the isolated clinical strains demonstrated that a high level of resistance was predominantly characteristic of Gram-negative microorganisms, including Escherichia coli, K. pneumoniae, and E. agglomerans. In contrast, Gram-positive pathogens showed high susceptibility to β-lactams, macrolides, and trimethoprim-sulfamethoxazole. The severity of community-acquired pneumonia caused by bacterial associations did not differ from that observed in monoinfection (p > 0.05).

CONCLUSION: The COVID-19 pandemic substantially affected the etiologic structure of pathogens causing community-acquired pneumonia, increasing the role of Gram-negative bacteria and their associations with fungi. Among the identified Gram-negative pathogens, multidrug-resistant isolates predominated. The findings underscore the need for further microbiologic investigations and regular updates of clinical guidelines for the treatment of community-acquired pneumonia, taking into account the principles of rational antibiotic therapy.

Respiratory syncytial virus remains one of the leading causes of lower respiratory tract infections worldwide and poses a serious threat to young children and older adults. This review aimed to analyze current strategies for the treatment and prevention of respiratory syncytial virus infection that have emerged as a result of fundamental advances in viral structural biology. The article reviews up-to-date epidemiological data, including changes in seasonality observed after the pandemic, as well as challenges in clinical diagnosis. It discusses evolution of passive immunoprophylaxis, and presents the results of studies evaluating the efficacy of novel recombinant vaccines for active immunization. Particular attention is paid to the assessment of promising agents for etiotropic therapy. The available evidence indicates that the introduction of new preventive and therapeutic interventions makes it possible to shift respiratory syncytial virus infection into the category of manageable diseases. An important future task is the establishment of continuous molecular epidemiological surveillance to monitor the potential development of viral resistance to existing therapeutic and preventive agents.

Studies of water bodies in India and Bangladesh have shown that removal of large particles from water reduces the incidence of cholera. Detection of aggregated communities of Vibrio cholerae (biofilms) provided evidence of their role in cholera epidemiology and stimulated investigation of biofilm forms. Summarizing available data in this field is particularly relevant because there are no unified methods for assessing biofilm formation and quantitatively determining the microorganisms comprising biofilms. The work aimed to evaluate methodological approaches to investigating biofilm formation by V. cholerae, focusing on their detection and reproducibility in laboratories of different levels.

Models (in vitro, in vivo, and microcosm), as well as methods for biofilm detection, were analyzed. Scopus, Web of Science, MEDLINE, the Russian Science Citation Index, and other sources were used to prepare the review. Data were searched using the following keywords: Vibrio cholerae, биоплёнка (biofilm), методы (methods), микроскопия (microscopy), микрокосмы (microcosms), молекулярно-генетические (molecular genetic). The review included 63 original articles, 3 review articles, and 1 monograph.

The review summarizes current concepts regarding the process of V. cholerae biofilm formation. Methods for modeling on abiotic and biotic substrates, including field conditions, approaches to biofilm detection, and the use of in vivo methods to assess infectivity of biofilm cultures, are described. Particular attention is paid to the role of molecular genetic methods. According to the published data, the most effective strategy for studying biofilm formation is an integrated approach combining microbiologic, microscopic, and molecular genetic methods. The review also addresses current challenges and promising research directions in this field.

The analysis of current issues and research prospects in V. cholerae biofilms, including recent molecular genetic methods, demonstrates that investigation of biofilms formed by vibrios using a range of methods will allow deeper understanding of the general principles of bacterial coexistence in communities. This, in turn, will contribute to more effective strategies for combating infections, including cholera.

The editorial board of the journal “Epidemiology and Infectious Diseases” announces the retraction of the article “Nosocomial infections: New vistas in their prevention “ published in 2011; 16(1) by Pokrovskiy VI, et al. (10.17816/EID40498 EDN: NDSHUN).

The reason for retraction is duplicate publication in another journal without the publishers’ consent. Similar article: Pokrovskiy VI, Akimkin VG, Briko NI, et al. Nosocomial infections: New vistas in their prevention. Public Health care. 2011;(1):14–20. EDN: QBKAHZ. The editors found the publication of a similar article while monitoring the journal’s scientometric indicators. It was not possible to reliably determine to which journal the article was first submitted using available methods. Therefore, a decision was made to retract the article from the journal “Epidemiology and Infectious Diseases”.