Personalized bacteriophage therapy to treat pandrug-resistant spinal Pseudomonas aeruginosa infection.

Bone and joint infections (BJI) are one of the most difficult-to-treat bacterial infection, especially in the era of antimicrobial resistance. Lytic bacteriophages (phages for short) are natural viruses that can selectively target and kill bacteria. They are considered to have a high therapeutic potential for the treatment of severe bacterial infections and especially BJI, as they also target biofilms. Here we report on the management of a patient with a pandrug-resistant Pseudomonas aeruginosa spinal abscess who was treated with surgery and a personalized combination of phage therapy that was added to antibiotics. As the infecting P. aeruginosa strain was resistant to the phages developed by private companies that were contacted, we set up a unique European academic collaboration to find, produce and administer a personalized phage cocktail to the patient in due time. After two surgeries, despite bacterial persistence with expression of small colony variants, the patient healed with local and intravenous injections of purified phages as adjuvant therapy.

Adaptation of Amoeba Plate Test To Recover Legionella Strains from Clinical Samples.

The isolation of Legionella from respiratory samples is the gold standard for diagnosis of Legionnaires' disease (LD) and enables epidemiological studies and outbreak investigations. The purpose of this work was to adapt and to evaluate the performance of an amoebic coculture procedure (the amoeba plate test [APT]) for the recovery of Legionella strains from respiratory samples, in comparison with axenic culture and liquid-based amoebic coculture (LAC). Axenic culture, LAC, and APT were prospectively performed with 133 respiratory samples from patients with LD. The sensitivities and times to results for the three techniques were compared. Using the three techniques, Legionella strains were isolated in 46.6% (n = 62) of the 133 respiratory samples. The sensitivity of axenic culture was 42.9% (n = 57), that of LAC was 30.1% (n = 40), and that of APT was 36.1% (n = 48). Seven samples were positive by axenic culture only; for those samples, there were <10 colonies in total. Five samples, all sputum samples, were positive by an amoebic procedure only (5/5 samples by APT and 2/5 samples by LAC); all had overgrowth by oropharyngeal flora with axenic culture. The combination of axenic culture with APT yielded a maximal isolation rate (i.e., 46.6%). Overall, the APT significantly reduced the median time for Legionella identification to 4 days, compared with 7 days for LAC (P < 0.0001). The results of this study support the substitution of LAC by APT, which could be implemented as a second-line technique for culture-negative samples and samples with microbial overgrowth, especially sputum samples. The findings provide a logical basis for further studies in both clinical and environmental settings.

Differential introgression of uniparentally inherited markers in bison populations with hybrid ancestries.

Historical hybridization between Bison bison (bison) and Bos taurus (cattle) has been well documented and resulted in cattle mitochondrial DNA (mtDNA) introgression, previously identified in six different bison populations. In order to examine Y chromosome introgression, a microsatellite marker (BYM-1) with non-overlapping allele size distributions in bison and cattle was isolated from a bacterial artificial chromosome (BAC) clone, and was physically assigned to the Y chromosome by fluorescence in situ hybridization. BYM-1 genotypes for a sample of 143 male bison from 10 populations, including all six populations where cattle mtDNA haplotypes were previously identified, indicated that cattle Y chromosome introgression had not occurred in these bison populations. The differential permeability of uniparentally inherited markers to introgression is consistent with observations of sterility among first generation hybrid males and a sexual asymmetry in the direction of hybridization favouring matings between male bison and female cattle.