Phage typing of coagulase-negative staphylococci

The Staphylococci phages family: an overview

Due to their crucial role in pathogenesis and virulence, phages of Staphylococcus aureus have been extensively studied. Most of them encode and disseminate potent staphylococcal virulence factors. In addition, their movements contribute to the extraordinary versatility and adaptability of this prominent pathogen by improving genome plasticity. In addition to S. aureus, phages from coagulase-negative Staphylococci (CoNS) are gaining increasing interest. Some of these species, such as S. epidermidis, cause nosocomial infections and are therefore problematic for public health. This review provides an overview of the staphylococcal phages family extended to CoNS phages. At the morphological level, all these phages characterized so far belong to the Caudovirales order and are mainly temperate Siphoviridae. At the molecular level, comparative genomics revealed an extensive mosaicism, with genes organized into functional modules that are frequently exchanged between phages. Evolutionary relationships within this family, as well as with other families, have been highlighted. All these aspects are of crucial importance for our understanding of evolution and emergence of pathogens among bacterial species such as Staphylococci.

Relationship between slime production, antibiotic sensitivity and the phagetype of coagulase-negative staphylococci

Three hundred and three strains of coagulase-negative staphylococci (CNS) were collected from the fingers of healthy donors (289) and from blood cultures (14). Twelve different species were identified (5 S. auricularis, 45 S. capitis, 15 S. cohnii, 86 S. epidermidis, 23 S. haemolyticus, 37 S. hominis, 1 S. lentus, 5 S. saprophyticus, 7 S. sciuri, 6 S. simulans, 54 S. xylosus and 19 S. warneri). Amongst these CNS strains, 151 were slime producers, 112 were phage-typable and 188, 133, 126 and 91 were, respectively, resistant to penicillin, teicoplanin, erythromycin and kanamycin. Slime-producing strains were resistant to at least seven antibiotics with a probability of 0.01 < P < 0.05. Non-slime-producing strains were sensitive to all the tested antibiotics with a probability of 0.001 < P < 0.01. There was no direct relationship between antibiotic sensitivity and phage type, although a non-typable strain was more often resistant to seven or more antibiotics than a typable one (0.05 < P < 0.1).