In Vitro Activity of Three Commercial Bacteriophage Cocktails against Multidrug-Resistant Escherichia coli and Proteus spp. Strains of Human and Non-Human Origin

摘要

Background: Bacteriophages could represent a therapeutic alternative to treat infections caused by multidrug-resistant (MDR) pathogens. However, studies analyzing their activity against MDR Enterobacteriaceae are limited.\udMethods: The in vitro lytic activity of three commercial bacteriophage cocktails (PYO, INTESTI, Septaphage) was evaluated against 70 Escherichia coli and 31 Proteus spp. of human and non-human origin. Isolates were characterized by phenotypic and genotypic methods and included 82 MDR strains: 44 ESBL (of which 15 CTX-M-15-like, including ST131/ST648 E. coli), 27 pAmpC (of which 23 CMY-2-like, including ST131 E. coli), 3 ESBL plus pAmpC, and 8 carbapenemase producers. Phage susceptibility was determined using the spot test. \udResults: E. coli susceptibility to PYO, INTESTI, and Septaphage was 61%, 67%, and 9%, whereas that of Proteus spp. was 29%, 39%, and 19%, respectively. For the subgroup of ESBL-producing E. coli/Proteus spp., the following susceptible rates were recorded: PYO, 57%; INTESTI, 59%; and Septaphage, 11%. With regard to the pAmpC producers, 59%, 70% and 11% resulted susceptible to PYO, INTESTI, and Septaphage, respectively. Five out of 8 carbapenemase producers and 3 out of 4 colistin-resistant E. coli were susceptible to PYO and INTESTI.\udConclusions: This is the first study analyzing the activity of the above three cocktails against well-characterized MDR E. coli and Proteus spp. The overall narrow-spectrum of activity observed could be related to the absence of specific bacteriophages targeting these contemporary MDR strains that are spreading in different settings. Therefore, bacteriophages targeting emerging MDR pathogens need to be isolated and integrated in such bio-preparations.