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The objective of this study is to determine the in vitro susceptibility of Georgian bacteriophage cocktails on multidrug resistant (MDR) extended-spectrum beta-lactamase producing Escherichia coli (ESBL-EC) isolated from patients’ blood and urine cultures. A total of 615 E. coli isolates were included in this study. Phene Plate (PhP)-typing and phylogenetic grouping were used for the typing. Antimicrobial resistance profiles and ESBL production of all isolates were confirmed according to Clinical and Laboratory Standards Institute (CLSI) criteria. The activities of four bacteriophage cocktails (Enko-phage, SES-bacteriophage, Pyo-bacteriophage, and Intesti-bacteriophage) were determined against 142 ESBL-EC using in vitro spot tests. According to this, Enko-phage were active against 87.3% of the tested strains while that ratio was 81.7% for Intesti-bacteriophage, 81.7% for Pyo-bacteriophage, and 59.2% for SES-bacteriophage cocktails. Based on the contingency tests, the phage cocktails were observed to be statistically significantly (p < 0.001) more effective on ESBL-EC strains belonging to phylogenetic groups D and B2. The employed phage cocktails were found to be affective against all tested resistant types. These results are promising especially for the infections that are caused by MDR pathogens that are difficult to treat. As this is a preliminary step to the potential clinical trials to be designed for the country, in vitro confirmation of their success on a MDR ESBL-EC collection should be accepted as an initial action, which is encouraging to consider clinical trials of phage therapy especially in countries which are not introduce phage therapy.

BackgroundIn the present study, we sequenced the complete genomes of three novel bacteriophages v_B-Bak1, v_B-Bak6, v_B-Bak10 previously isolated from historical anthrax burial sites in the South Caucasus country of Georgia. We report here major trends in the molecular evolution of these phages, which we designate as “Basilisk-Like-Phages” (BLPs), and illustrate patterns in their evolution, genomic plasticity and core genome architecture.ResultsComparative whole genome sequence analysis revealed a close evolutionary relationship between our phages and two unclassified Bacillus cereus group phages, phage Basilisk, a broad host range phage (Grose JH et al., J Vir. 2014;88(20):11846-11860) and phage PBC4, a highly host-restricted phage and close relative of Basilisk (Na H. et al. FEMS Microbiol. letters. 2016;363(12)). Genome comparisons of phages v_B-Bak1, v_B-Bak6, and v_B-Bak10 revealed significant similarity in sequence, gene content, and synteny with both Basilisk and PBC4. Transmission electron microscopy (TEM) confirmed the three phages belong to the Siphoviridae family. In contrast to the broad host range of phage Basilisk and the single-strain specificity of PBC4, our three phages displayed host specificity for Bacillus anthracis. Bacillus species including Bacillus cereus, Bacillus subtilis, Bacillus anthracoides, and Bacillus megaterium were refractory to infection.ConclusionsData reported here provide further insight into the shared genomic architecture, host range specificity, and molecular evolution of these rare B. cereus group phages. To date, the three phages represent the only known close relatives of the Basilisk and PBC4 phages and their shared genetic attributes and unique host specificity for B. anthracis provides additional insight into candidate host range determinants.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-5056-4) contains supplementary material, which is available to authorized users.

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Purpose: Salmonella Enteritidis has emerged as global concern regarding quinolone resistance and invasive potential. Although quinolone-resistant S. Enteritidis has been observed with high frequency in Thailand, information on the mechanism of resistance acquisition is limited. This study aimed to investigate the quinolone resistance determinants in clinical nalidixic acid (NAL) resistant S. Enteritidis isolates collected nationwide in Thailand.Methods & Materials: To elucidate the quinolone resistance mechanism, a total of 190 clinical isolates of NAL-resistant S. Enteritidis were collected throughout Thailand, and the quinolone resistance-determining region (QRDR) mutational status and the plasmid-mediated quinolone resistance (PMQR) determinants were investigated in the context of resistance levels to NAL, norfloxacin (NOR) and ciprofloxacin (CIP). In addition, the relationship between these resistance determinants and multi-locus variable number of tandem repeat analysis (MLVA) was to elucidate the dissemination of specific clones.Results: The most commonly affected codon in gyrA was 87, followed by 83. Double codon mutation in gyrA was found in an isolate with high-level resistance to NAL, NOR and CIP. A new mutation causing serine to isoleucine substitution at codon 83 was identified in eight isolates. Eighteen qnrS1-carrying isolates showing nontypical quinolone resistance. One isolate carrying both the qnrS1 gene and a gyrA mutation showed a high level of quinolone resistance. Genotyping by MLVA suggested the presence of a possible clonal expansion of NAL-resistant S. Enteritidis nationwide. Conclusion:Our data suggested that NAL-resistant isolates with single quinolone resistance determinant may potentially become fluoroquinolone resistant by acquiring secondary determinants.

Aims: Sulphate-reducing bacteria (SRB) are ecologically important group of anaerobic micro-organisms that can reduce sulphate to form hydrogen sulphide-a toxic gas causing iron corrosion on metal surfaces. In this work, SRB strains were isolated from aquatic environments in the country of Georgia to determine their lysogenicity and the role of temperate phages in host metabolism. Methods and Results: SRB strains were isolated in samples from the Black Sea coast of Georgia. Based on their genetic, cytological and physiological properties of bacteria, 10 Georgian isolates were assigned to the genus Desulfovibrio. Temperate bacteriophages were induced from three out of ten strains by UV-exposure. Comparison of metal (Fe and Cr) reduction and utilization of various carbon sources by the wild-type (lysogenic) bacterial strains and their UV-irradiated counterparts was done. Conclusions: Temperate phage in the cells of SRB could alter significant functions of bacteria and may have a contribution in the acquisition of different traits by SRB. Significance and Impact of the Study: This article pointed to a significant role for temperate bacteriophages in the metabolism and metabolic potential of host strains of SRB, which were first isolated from the aquatic environment of Georgia.

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