Clinical trials of new culture media for staphylococcus isolation.

A comparative analysis of the quality of the developed nutrient media, Baird-Parker dry agar base and Vogel-Johnson dry agar Base and foreign analogues, was done based on results of clinical trials. The tested media were qualified by the main biological parameters, such as sensitivity, growth rate, and differentiating and inhibiting properties. The evaluation of statistical reliability of the results of trials of clinical samples was evaluated taking into account the number of parallel studies and the number of matches of the results of studies conducted by different performers. 116 clinical samples of received by a laboratory of the testing laboratory center for research from hospital no.164 over the period of clinical trials were analyzed. 46 cultures of potential pathogens were isolated when culturing on test and control media: S. aureus -35; S. epidermidis-6; S. saprophyticus - 5. Lecithinase activity on the medium "Baird-Parker dry agar Base" and mannitol fermentation on the medium "Vogel-Johnson dry agar Base" in the preliminary phenotypic test allow the isolation and differentiation of clinical isolates of S. aureus from S. epidermidis, and S. saprophyticus.

Next-Generation Antibiotics, Bacteriophage Endolysins, and Nanomaterials for Combating Pathogens.

This review presents various strategies to fight causative agents of infectious diseases. Species-specific programmable RNA-containing antibiotics open up new possibilities for creating next-generation of personalized drugs based on microbiome editing and can serve as a new tool for selective elimination of pathogenic bacterial species while keeping intact the rest of microbiota. Another promising approach in combating bacterial infections is genome editing using the CRISPR-Cas systems. Expanding knowledge on the molecular mechanisms of innate immunity has been actively used for developing new antimicrobials. However, obvious risks of using antibiotic adjuvants aimed at activation of the host immune system include development of the autoimmune response with subsequent organ damage. To avoid these risks, it is essential to elucidate action mechanisms of the specific ligands and signal molecules used as components of the hybrid antibiotics. Bacteriophage endolysins are also considered as effective antimicrobials against antibiotic-resistant bacteria, metabolically inactive persisters, and microbial biofilms. Despite significant advances in the design of implants with antibacterial properties, the problem of postoperative infections still remains. Different nanomodifications of the implant surface have been designed to reduce bacterial contamination. Here, we review bactericidal, fungicidal, and immunomodulating properties of compounds used for the implant surface nanomodifications, such as silver, boron nitride nanomaterials, nanofibers, and nanogalvanic materials.

[Comparison of hemolytic activity and hemolytic toxin genes of Staphylococcus aureus clinical strains, isolated in Russia.]

Clinical strains of Staphylococcus aureus were tested for hemolytic activity on blood agar, in the PCR test and by analyzing the gene alleles of hemolytic toxins. The study analyzed the information content of the phenotypic determination of hemolytic activity to assess the pathogenic properties of S. aureus isolates.

[Molecular genetic identification of Staphylococcus aureus strain, caused a foodborne illness outbreak in St. Petersburg in 2013].

BACKGROUND: Staphylococcus aureus is one of the most important human pathogens and causes over 100 nosologicalforms of diseases. The lack of data on the spread of S. aureus genetic types specific for different forms of staphylococcal infections in Russia makes it difficult to timely identify and control strains of this epidemiologically dangerous bacterial pathogen. OBJECTIVE: The aim of the study was to carry out a molecular genetic research of S. aureus isolates obtained during a widespread foodborne illness outbreak among builders at the Pulkovo airport in St. Petersburg in 2013. METHODS: The ability of the isolates to produce staphylococcal enterotoxins was studied by immunoenzyme techniques. Gene typing was carried out by sequence-specific primer-based PCR, as well as by sequencing genomic nucleotide sequences of two independent isolates of the pathogen. RESULTS: An enterotoxin A gene in genomes of S. aureus isolates etiologically associated with the outbreak was identified. The production of enterotoxin A by the isolates was shown. According to the complex analysis all isolates producing staphylococcal enterotoxins were identical and constituted the S. aureus strain, sequence-type ST30 and spa-type t2509. The genome of the identified S. aureus strain carried a set of various staphylococcal toxins. The full genome sequence among other techniques revealed high levels of similarity between genomes of the strain under study and well-known reference strain S aureus MRSA 252. CONCLUSION: The complete molecular genetic study of the S. aureus strain involved into the widespread foodborne illness outbreak was first carried out in Russia, allowing of further using the strain as a Russian reference strain to study potential epidemic outbreaks in the Russian Federation.

[An algorithm for identification of CTX-M-type beta-lactamase genes using restriction fragment length polymorphism analysis of PCR-product].

The algorithm of the identification of the bla(CTX-M) genes coding CTX-M-type beta-lactamases providing resistance to cephalosporins III-IV was developed. This algorithm provides identification of 49 genes of 96 genes presented in the GenBank database so far. Remaining 47 genes can be identified as consisting of small sub-groups composed of 2-6 genes with the exception of sub-group of the bla(CTX-M-14)-like genes composed of 13 genes. The identification of the bla(CTX-M) genes is based on two-step restriction fragment length polymorphism analysis of 544 bp PCR-product (PCR-RFLP). In the first step, determination of subtype (cluster) of the bla(CTX-M) gene occurred using the restriction nuclease Alu I: cluster 1, -2, -8, -9 or -25. Moreover, four genes can be identified just at this step: bla(CTX-M)-59, (cluster 2); bla(CTX-M-63) (cluster 8), bla(CTX-M-45) (cluster 9), and bla(CTX-M-78) (hybrid gene between cluster 2 and cluster 25). At the second step gene identification goes on inside of each cluster separately using a set of 26 restriction nucleases. As a result of the PCR-RFLP-analysis, 23 bla(CTX-M) genes can be identified at the cluster 1, 11 genes--at the cluster 2, 4 genes--at the cluster 8, 9 genes--at the cluster 9, 1 gene--at the cluster 25, and 2 hybrid genes: bla(CTX-M-78) (between clusters 2 and 25), and bla(CTX-M-64) (between clusters 1 and 9). The described algorithm was used for identification of the blac(CTX-M) genes (n = 585) detected in Enterobacteriaceae nosocomial isolates (n = 877), collected from Russial hospitals in 2003-2007. It was shown that major genes belonged to cluster 1 (n = 543), namely--bla(CTX-M-15) gene (n = 515), bla(CTX-M-3) (n = 25), bla(CTX-M-22) (n = 1), bla(CTX-M-23) (n = 1), and bla(CTM-34) (n = 1). Moreover, the genes atributed to cluster 2 were identified: bla(CTX-M-2) (n = 1), and bla(CTX-M-5) (n = 4); and genes belonged to cluster 9: bla(CTX-M-9) (n = 2), and bla(CTX-M-14) (n = 35).

[Genetic determinants of antibacterial resistance among nosocomial Escherichia coli, Klebsiella spp., and Enterobacter spp. isolates collected in Russia within 2003-2007].

Nosocomial bacterial isolates collected within 2003-2004 (n=411) and 2005-2007 (n=422) were highly resistant to cephalosporins III-IV and antibacterials of other groups (aminoglycosides, fluoroquinolons, chloramphenicol, and co-trimoxazole). Genes encoding TEM, SHV, CTX-M, OXA-2, and AmpC types of beta-lactamases (BLs) in the E. coli, Klebsiella spp., and Enterobacter spp. isolates were detected using polymerase chain reaction (PCR). Prevalent CTX-M-type BLs were detected in 85% of the E. coli, 87% of the Klebsiella spp., and 38% of the Enterobacter spp. isolates of the first strain collection and in 94% of the E. coli, 91% of the Klebsiella spp., and 38% of the Enterobacter spp. isolates of the second one. Genes belonging to three subtypes of blacTx-M genes were identified: bla(CTX-M-1) (228 bla(CTX-M-15) and six bla(CTX-M-3) of the first strain collection; 275 bla(CTX-M-15), three bla(CTX-M-3), and one bla(CTX-M-22) of the second one), bla(CTX-M-2) (one bla(CTX-M-5) of the first strain collection and one bla(CTX-M-2) of the second one), bla(CTX-M-9) (17 bla(CTX-M-14) and one bla(CTX-M-9) of the first strain collection; seven bla(CTX-M-14) and one bla(CTX-M-9) of the second one). Three isolates of the first strain collection and one isolate of the second one carried two genes belonging to two different subtypes, i.e., bla(CTX-M-15) and bla(CTX-M-14) simultaneously. The bacterial isolates had high levels of associative resistance to ciprofloxacin, co-trimoxazole, gentamicin, amikacin, and chloramphenicol associated with the resistance gene cassettes aadA1, aadA2, aadA5, aadB, aacA4, aac(6')Ib; dfrA1, dfrA5, dfrA12, dfrA17, cmlA1, ereA2, and catB8 in the class 1 integrons and the resistance gene cassettes dfrA1, sat1, and aadA1 in the class 2 integrons.

[Genetic environments of bla(CTX-M) genes located on conjugative plasmids of Enterobacteriaceae nosocomial isolates collected in Russia within 2003-2007].

The study showed that bla(CTX-M) genes were present in the genomes of 71% of cephalosporin resistant Enterobacteriaceae nosocomial isolates (n=833) collected in Russian hospitals within 2003-2007, including 91% of E.coli, 90% of Klebsiella spp., 38% of Enterobacter spp., 31% of Citrobacter spp. (n=9), and 36% of the other Enterobacteriaceae species. The genes belonging to the following subtypes (clusters) were identified: bla(CTX-M-1) (529 bla(CTX-M-15) genes; 25 bla(CTX-M-3) genes; 1 bla(CTX-M-22) gene, 1 bla(CTX-M-23) gene, and 1 bla(CTX-M-34) gene); bla(CTX-M-2) (1 bla(CTX-M-2) gene, and 4 bla(CTX-M-5) genes), and bla(CTX-M-9) (2 bla(CTX-M-9) genes, and 28 bla(CTX-M-14) genes). It was shown that bla(CTX-M) genes were located on high-molecular weight (60-160 bp) conjugative plasmids belonging mainly to the incompatibility groups IncF, IncL/M and IncA/C (bla(CTX-M-15) gene); IncL/M(bla(CTX-M-3) gene); and IncF, IncL/Mand IncI1-ly (CTX-M-14 gene). The gene environments of bla(CTX-M) genes were shown specific for the subtype of the genes. A mobile genetic element ISEcp1 (in some cases deleted or inserted by IS26, IS1, IS10, resTn2, or resTn3 sequences, in direct or reverse position) were detected upstream of bla(CTX-M-3), bla(CTX-M-14), and bla(CTX-M-15) genes. A special characteristic was the sequence between ISEcp1 and bla(CTX-M) gene: 48 bp for bla(CTX-M-15) (except 1 E.coli isolate having such a sequence deleted by 3 bp); 127 bp for bla(CTX-M-3); 42 bp for bla(CTX-M-14). Downstream of bla(CTX-M) and bla(CTX-M-15) genes in the major bacterial isolates orf477 mucA and Delta orf477-Delta mucA sequences were detected respectively. Two isolates had additional Delta orf3 insertion inside of Delta orf477-Delta mucA sequence. Insertion sequence IS903 (intact or deleted) was detected downstream of bla(CTX-M-14) gene. Unlike the others, bla(CTX-M-2) and bla(CTX-M-9) genes were located inside of ISCR1 mobile element, downstream of class 1 integron and orf513 sequence.

[Stable expression of heterologous proteins in salmonella: problems and approaches to their designing]. / Stabil'naia ékspressiia geterologicheskikh belkov v salmonella: problemy i podkhody k ikh resheniiu.

Live attenuated Salmonella vaccines may be used as carriers of heterologous antigens. The optimum expression system for each heterologous antigen requires to be established on an individual basis. This will ensure that the antigen in question is produced at appropriate levels and in the correctly folded conformation. Different techniques for producing stable recombinant Salmonella strains suitable for their use as bivalent vaccines.

[Creation of genomic DNA libraries for Pseudomonas mallei and Pseudomonas pseudomallei]. / Sozdanie bibliotek genomnoi DNK Pseudomonas mallei i Pseudomonas pseudomallei.

The genomic libraries of P. mallei and P. pseudomallei species were constructed in Escherichia coli. The chromosomal DNA of P. pseudomallei C-141 strain has been cloned into the cosmid vector pHC79 and the broad host range plasmid vector pES154. The chromosomal DNA of P. mallei [symbol: see text]-5 strain has been cloned into the plasmid vector pSUP202. The recombinant clones of the genomic libraries were screened by the enzyme-linked immunoadsorbent assay (ELISA) to detect the production of Pseudomonas antigens: 28 clones were positive. Twelve recombinant strains demonstrated specific antigenic determinants of P. mallei and P. pseudomallei by immunoblotting. Cloned proteins of P. mallei and P. pseudomallei have molecular weights from 30 to 70 kD. A new method for introducing foreign genes into Pseudomonas genomes is offered. P. mallei strains with the chromosomally integrated plasmids pSM are universal recipients for ColEI-based cloning vectors.

[Pseudomonas mallei and Pseudomonas pseudomallei: introduction and maintenance of natural and recombinant plasmid replicons]. / Pseudomonas mallei i Pseudomonas pseudomallei: vvedenie i podderzhanie prirodnykh i rekombinantnykh plazmidnykh replikonov.

Comparative analysis of recipient activity of Pseudomonas mallei, Pseudomonas pseudomallei, and Pseudomonas cepacia strains towards naturally occurring and recombinant plasmid replicons was carried out. Autonomic broad host range vector plasmids based on RSF1010(IncQ) and pSa(IncW) replicons as well as integrative vectors based on pSUP202(Co1E1) replicon have been constructed. The study has shown that naturally occurring plasmids RSF1010(IncQ), pSa(IncW), R15(IncN), and RP4(IncP) are being efficiently transferred and stably maintained in investigated Pseudomonas strains. However, recombinant plasmids with the mini-replicon pSa which are stable in Escherichia coli have shown segregative instability in Pseudomonas strains, whereas derivatives of plasmid RSF1010 demonstrated different stability depending on the type of insertion. Plasmid pSUP202 derivative integrative vector pSM525 is efficiently introduced and stably maintained in P. mallei C-5 strain. Two vector systems for genetic manipulations in P.mallei and P.pseudomallei cells have been developed.

[Transformation of pathogenic pseudomonas by plasmid DNA]. / Transformatsiia patogennykh psevdomonad plazmidnoi DNK.

The possibility has been shown of the genetical transformation of Pseudomonas mallei strains by the purified DNA of the plasmids RSF1010, pES154, pBS222 and pBR325. The frequency of transformation varied from 1.2 x 10(1) to 2.0 x 10(2) depending on the plasmid DNA and transformation technique used in the experiments. Pseudomonas pseudomallei cells could not be transformed by the methods described in the paper.