In-vitro bacteriocin-mediated antagonism by oral streptococci against human carrier strains of staphylococci

To the question of the relevance of the development and prospects for the use of the bacteriophage <i>Streptococcus pneumoniae</i>

Introduction. The prevalence of Streptococcus pneumoniae strains causing invasive forms of pneumococcal infection and the growing rates of antibiotic resistance of individual serotypes of the pathogen pose a number of urgent and socially significant tasks the search for new antimicrobial agents for prevention and treatment. Objective. To analyze the data of scientific publications of domestic and foreign authors on the problems of practical use and prospects for the development of the bacteriophage S. pneumoniae drug aimed at the actual serotypes of the pathogen. Results. Analysis of literary sources in scientific electronic databases and publishing houses eLibrary.Ru, ScienceDirect, Scopus, PubMed, Springerlink, Wiley Online Library, Annual reviews allowed us to summarize information about four isolated lytic bacteriophages of S. pneumoniae and their endolysins, as well as about two lysogenic phages, to present data on the clinical efficacy of streptococcal bacteriophage in pneumococcal infection in animals and humans. The results of search queries on the most significant and widespread serotypes of S. pneumoniae in the territory of the Russian Federation have established the predominance in the structure of variants 19F, 14, 9V/A, 15 A/F, 6 A/B/C/D, 3 and 23F. Some of them are characterized by a high level of antibiotic resistance and cause invasive forms of the disease, and serotypes 15 A/F/C, 6 C/D are not represented in modern vaccines, which increases the relevance of the development and use of pneumococcal bacteriophage, including intraspecific typing of significant and common serotypes. Conclusion. Based on the analysis of the current state of the issue of pneumococcal bacteriophages, the information obtained on the circulation of topical strains of S. pneumoniae on the territory of the Russian Federation and their serotype landscape, it is concluded that the development of the bacteriophage S. pneumoniae drug is relevant as a means of targeted action for the prevention, diagnosis and personalized therapy of human diseases of pneumococcal etiology.

Inclusion of 5-[4-(1-dodecanoylpyridinium)]-10,15,20-triphenylporphine in supramolecular aggregates of cationic amphiphilic cyclodextrins: physicochemical characterization of the complexes and strengthening of the antimicrobial photosensitizing activity

Recent findings suggest that visible light-promoted photooxidative processes mediated by sensitizers of appropriate chemical structure could represent a useful tool for properly addressing the problem of the increasing occurrence of infectious diseases caused by multiantibiotic-resistant microbial pathogens. The monocationic meso-substituted porphyrin 5-[4-(1-dodecanoylpyridinium)]-10,15,20-triphenyl-porphine (TDPyP) complexed into supramolecular aggregates of cationic amphiphilic beta-cyclodextrin (SC(6)NH(2)) (mean diameter = 20 nm) appeared to be endowed with favorable properties to act as a photosensitizing agent, including a very high quantum yield (Phi(Delta) = 0.90) for the generation of the highly reactive oxygen species, singlet oxygen ((1)O(2)). Although the yield of (1)O(2) generation was comparable to that obtained after TDPyP incorporation into cationic unilamellar liposomes of N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP) SC(6)NH(2)-bound TDPyP was more active than DOTAP-bound TDPyP in photosensitizing the inactivation of the Gram-positive methicillin-resistant bacterium Staphylococcus aureus (MRSA). At variance with DOTAP-bound TDPyP, photoactivated SC(6)NH(2)-bound TDPyP was efficient also in photokilling Gram-negative bacterial pathogens, such as Escherichia coli . These observations are in agreement with the well-known photobactericidal effect of positively charged porphyrin derivatives, which can be markedly enhanced after incorporation into carriers with multiple positive charges. In addition, transmission electron microscopy studies revealed that potentiation of the TDPyP-mediated photobactericidal effect by incorporation into SC(6)NH(2) is a consequence of the carrier's ability to promote an efficient crossing of the very tightly organized three-dimensional architecture of the bacterial outer wall by the embedded porphyrin so that a prompt interaction between the short-lived photogenerated (1)O(2) and the nearby targets, whose integrity is critical for cell survival, can take place.

Inhibition of methicillin-resistant Staphylococcus aureus colonization of oral cavities in newborns by viridans group streptococci

We investigated the role of viridans group streptococci in the prevention of colonization with methicillin-resistant Staphylococcus aureus (MRSA) in neonatal intensive care units. During a 26-month period at a children's hospital, 207 (49.9%) of 415 newborns were colonized with MRSA by the time of discharge. Two groups of newborns with matching durations of hospitalization were compared with regard to the prevalence of future colonization with MRSA: group 1 (103 patients) did not acquire colonization with viridans group streptococci and group 2 (63 patients) did acquire colonization with viridans group streptococci at birth or by 1 to 2 weeks (age, < or =11 days). The rate of colonization among patients in group 2 (9.5%) was significantly lower than that among patients in group 1 (44.7%; P<.001). No significant difference in patient characteristics (e.g., birth weight, diseases) was observed. These results indicate that viridans group streptococci, as bacteria that formerly occupied the oral cavities in newborns, may inhibit later colonization with MRSA.