Gram Positive Cocci
An outbreak of staphylococcal infection involving umbilical cords of seven newborn babies was reported in the nursery. Bacteriological survey reveals that two nurses have a large number of Staphylococcus aureus in the nasopharynx. What test should be performed to determine whether these nurses may have been responsible for the outbreak?(AIPG 2009)
|C||Nasopharyngeal culture on mannitol salt agar|
|D||Protein A typing|
a. Bacterial viruses (bacteriophages or phages) can attach to separate receptors on the cell walls of various strains of S. aureus. Different specific receptors have been identified and used as the basis of epidemiological typing of pathogenic S. aureus strains.
b. Typical cultures from the outbreak and strains obtained from hospital personnel can be subjected to a standardized procedure using a series of bacteriophages that attack S. aureus strains. If they have the same phage susceptibility, the nurses would be responsible for the outbreak.
c. Phages of S. aureus have narrow host range. Therefore, for epidemiological studies, strains of S. aureus can be distinguished by their patterns of lysis by internationally recognized set of 23 standard typing phages.
d. Phage typing Centre→ Lady Hardinge Medical College New Delhi