Bacteriophages in human samples

Bacteriophages are abundant in human biomes and therefore in human clinical samples. Although this is usually not considered, they might interfere with the recovery of bacterial pathogens at two levels: 1) by propagating in the enrichment cultures used to isolate the infectious agent, causing the lysis of the bacterial host and 2) by the detection of bacterial genes inside the phage capsids that mislead the presence of the bacterial pathogen. To unravel these interferences, human samples (n=271) were analyzed and infectious phages were observed in 11% of blood culture, 28% of serum, 45% of ascitic fluid, 14% of cerebrospinal fluid and 23% of urine samples. The genetic content of phage particles from a pool of urine and ascetic fluid samples showed bacteriophages infecting different bacterial genera but also many bacterial genes packaged in the phage capsids, including antibiotic resistance genes and 16SrDNA.