Most cited article - PubMed ID 21625877
The influence of external factors on bacteriophages--review
Reducing bacterial pathogen contamination not only improves overall global public health but also diminishes food waste and loss. The use of lytic bacteriophages (phages) that infect and kill bacteria could be a beneficial tool for suppressing bacterial growth during dairy products storage time. Four Enterobacter cloacae (E. cloacae) complex isolates which were previously isolated from contaminated dairy products were used to identify lytic phages in wastewater. Phages specific to multi-drug resistant (MDR) E. cloacae complex 6AS1 were isolated from local sewage. Two novel phages vB_EclM-EP1 and vB_EclM-EP2 were identified as myoviral particles and have double-stranded DNA genome. Their host range and lytic capabilities were detected using spot test and efficiency of plating (EOP) against several bacterial isolates. The phages had a latent period of 30 min, and a large burst size of about 100 and 142 PFU/cell for vB_EclM-EP1 and vB_EclM-EP2, respectively. Both phages were viable at pH ranging 5-9 and stable at 70 °C for 60 min. The individual phages and their cocktail preparations (vB_EclM-EP1 and vB_EclM-EP2) reduced and inhibited the growth of E. cloacae complex 6AS1 during challenge test in milk and yogurt samples. These results indicate that the E. cloacae complex-specific phages (vB_EclM-EP1 and vB_EclM-EP2) have a potential application as microbicidal agents in packaged milk and milk derivatives during storage time. In addition, our environment is a rich sources of lytic phages which have potential use in eliminating multidrug-resistant isolates in food industry as well as in biocontrol.
- Keywords
- Bacteriophage, Biocontrol, Enterobacter cloacae complex, Milk, Yogurt,
- MeSH
- Bacteriophages * genetics MeSH
- Enterobacter cloacae MeSH
- Yogurt MeSH
- Milk microbiology MeSH
- Refuse Disposal * MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
Schlegelella thermodepolymerans is a moderately thermophilic bacterium capable of producing polyhydroxyalkanoates-biodegradable polymers representing an alternative to conventional plastics. Here, we present the first complete genome of the type strain S. thermodepolymerans DSM 15344 that was assembled by hybrid approach using both long (Oxford Nanopore) and short (Illumina) reads. The genome consists of a single 3,858,501-bp-long circular chromosome with GC content of 70.3%. Genome annotation identified 3,650 genes in total, whereas 3,598 open reading frames belonged to protein-coding genes. Functional annotation of the genome and division of genes into clusters of orthologous groups revealed a relatively high number of 1,013 genes with unknown function or unknown clusters of orthologous groups, which reflects the fact that only a little is known about thermophilic polyhydroxyalkanoates-producing bacteria on a genome level. On the other hand, 270 genes involved in energy conversion and production were detected. This group covers genes involved in catabolic processes, which suggests capability of S. thermodepolymerans DSM 15344 to utilize and biotechnologically convert various substrates such as lignocellulose-based saccharides, glycerol, or lipids. Based on the knowledge of its genome, it can be stated that S. thermodepolymerans DSM 15344 is a very interesting, metabolically versatile bacterium with great biotechnological potential.
- Keywords
- PHA, de novo assembly, functional annotation, hybrid assembly,
- MeSH
- Molecular Sequence Annotation MeSH
- Comamonadaceae genetics MeSH
- Genome, Bacterial * MeSH
- Sequence Analysis, DNA MeSH
- Whole Genome Sequencing MeSH
- Base Composition MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Nowadays, phage therapy emerges as one of the alternative solutions to the problems arising from antibiotic resistance in pathogenic bacteria. Although phage therapy has been successfully applied both in vitro and in vivo, one of the biggest concerns in this regard is the stability of phages in body environment. Within the scope of this study, microencapsulation technology was used to increase the resistance of phages to physiological conditions, and the resulting microcapsules were tested in environments simulating body conditions. For this purpose, Bacillus subtilis, Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Enteritidis), and Salmonella enterica subsp. enterica serovar Typhimurium (Salmonella Typhimurium) phages were isolated from different sources and then microencapsulated with 1.33% (w/v) sodium alginate using a spray dryer to minimize the damage of physiological environment. Stability of microcapsules in simulated gastric fluid and bile salt presence was tested. As a consequence, the maximum titer decrease of microencapsulated phages after 2-h incubation was found to be 2.29 log unit for B. subtilis phages, 1.71 log unit for S. Enteritidis phages, and 0.60 log unit for S. Typhimurium phages, while free phages lost their viability even after a 15-min incubation. Similarly, microencapsulation was found to increase the stability of phages in the bile salt medium and it was seen that after 3 h of incubation, the difference between the titers of microencapsulated phages and free phages could reach up to 3 log unit.
- MeSH
- Alginates MeSH
- Bacteria classification virology MeSH
- Bacteriophages drug effects isolation & purification physiology MeSH
- Cell Encapsulation * MeSH
- Microbial Viability MeSH
- Drug Stability MeSH
- Gastric Juice MeSH
- Bile Acids and Salts pharmacology MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Alginates MeSH
- Bile Acids and Salts MeSH
Pseudomonas aeruginosa is an opportunistic pathogen that causes serious infections, especially in patients with immunodeficiency. It exhibits multiple mechanisms of resistance, including efflux pumps, antibiotic modifying enzymes and limited membrane permeability. The primary reason for the development of novel therapeutics for P. aeruginosa infections is the declining efficacy of conventional antibiotic therapy. These clinical problems caused a revitalization of interest in bacteriophages, which are highly specific and have very effective antibacterial activity as well as several other advantages over traditional antimicrobial agents. Above all, so far, no serious or irreversible side effects of phage therapy have been described. Five newly purified P. aeruginosa phages named vB_PaeM_WP1, vB_PaeM_WP2, vB_PaeM_WP3, vB_PaeM_WP4 and vB_PaeP_WP5 have been characterized as potential candidates for use in phage therapy. They are representatives of the Myoviridae and Podoviridae families. Their host range, genome size, structural proteins and stability in various physical and chemical conditions were tested. The results of these preliminary investigations indicate that the newly isolated bacteriophages may be considered for use in phagotherapy.
- MeSH
- Bacteriophages classification genetics isolation & purification physiology MeSH
- Biological Therapy MeSH
- Host Specificity MeSH
- Humans MeSH
- Molecular Sequence Data MeSH
- Myoviridae classification genetics isolation & purification physiology MeSH
- Sewage virology MeSH
- Podoviridae classification genetics isolation & purification physiology MeSH
- Pseudomonas Infections microbiology therapy MeSH
- Pseudomonas aeruginosa virology MeSH
- Viral Proteins genetics MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Sewage MeSH
- Viral Proteins MeSH