RESUMEN
BACKGROUND: Urinary tract infections (UTIs) are among the most prevalent microbial diseases and their financial burden on society is substantial. The continuing increase of antibiotic resistance worldwide is alarming so that well-tolerated, highly effective therapeutic alternatives are urgently needed. OBJECTIVE: To investigate the effect of bacteriophages on Escherichia coli and Klebsiella pneumoniae strains isolated from the urine of patients suffering from UTIs. MATERIAL AND METHODS: Forty-one E. coli and 9 K. pneumoniae strains, isolated from the urine of patients suffering from UTIs, were tested in vitro for their susceptibility toward bacteriophages. The bacteriophages originated from either commercially available bacteriophage cocktails registered in Georgia or from the bacteriophage collection of the George Eliava Institute of Bacteriophage, Microbiology and Virology. In vitro screening of bacterial strains was performed by use of the spot-test method. The experiments were implemented three times by different groups of scientists. RESULTS: The lytic activity of the commercial bacteriophage cocktails on the 41 E. coli strains varied between 66% (Pyo bacteriophage) and 93% (Enko bacteriophage). After bacteriophage adaptation of the Pyo bacteriophage cocktail, its lytic activity was increased from 66 to 93% and only one E. coli strain remained resistant. One bacteriophage of the Eliava collection could lyse all 9 K. pneumoniae strains. CONCLUSIONS: Based on the high lytic activity and the potential of resistance optimization by direct adaption of bacteriophages as reported in this study, and in view of the continuing increase of antibiotic resistance worldwide, bacteriophage therapy is a promising treatment option for UTIs highly warranting randomized controlled trials.
RESUMEN
Staphylococcus aureus phage ISP was lyophilized, using an Amsco-Finn Aqua GT4 freeze dryer, in the presence of six different stabilizers at different concentrations. Stability of the lyophilized phage at 4 °C was monitored up to 37 months and compared to stability in Luria Bertani broth and physiological saline at 4 °C. Sucrose and trehalose were shown to be the best stabilizing additives, causing a decrease of only 1 log immediately after the lyophilization procedure and showing high stability during a 27 month storage period.
Asunto(s)
Liofilización/métodos , Fagos de Staphylococcus/fisiología , Staphylococcus aureus/virología , Liofilización/instrumentación , Microscopía Electrónica de Transmisión , Fagos de Staphylococcus/efectos de los fármacos , Fagos de Staphylococcus/ultraestructura , Sacarosa/farmacología , Factores de Tiempo , Trehalosa/farmacologíaRESUMEN
Identification and classification of bacteriophages remains a cumbersome process even with the use of genotypic approaches, due to the lack of genes present in all phages. Restriction fragment length polymorphism analysis (RFLP) of the viral genome is a universal approach, but RFLP fingerprints obtained on agarose gels remain difficult to compare between laboratories. Here we describe the digitization of RFLP of viral genomes by amplification of all restriction fragments - after ligation of adapters - using primers complementary to the adapters only. Since one of the primers is fluorescently labelled, the restriction fragments become visible to a fluorescent capillary electrophoresis system (ABI310) and their lengths can be digitized immediately. The digitized fluorescent RFLP (fRFLP) fingerprint can be stored as an entry in a library. Dendrogram construction of the fRFLP fingerprints obtained for a total of 69 Caudovirales (tailed bacteriophages) showed that genomically and/or serologically closely related phages clustered, whereas host range was not completely in correspondence with genotype. fRFLP might be a tool for quickly establishing the relationship of newly isolated phages to previously isolated ones and for constructing an fRFLP library electronically accessible on the internet, to which fRFLP patterns of new phages can be compared.