Phage-typing patterns and lysogenicity of methicillin-resistant strains of Staphylococcus aureus from Sydney, Australia, 1965-85

Abstract

Summary. Methicillin-resistant strains of Staphylococcus aureus isolated at the Royal Prince Alfred Hospital since 1965 were differentiated by phage-typing and by their lysogenic status. Most of these strains were isolated during two periods, 1965-72 and 1976-85. Nearly all of the strains isolated in the first period had one of four phagetyping patterns. Strains with each typing pattern carried two prophages; these eight phages were all different, as characterised by serological grouping and lytic spectrum. Lysogenisation of the non-lysogenic strain 1489 with each of these phages narrowed its phage-typing pattern; the typing pattern of the double lysogens was generally similar to and occasionally identical with that of the host strain that had yielded the pair of phages. In the second period, strains with one of five other phage-typing patterns predominated. Representatives of each of these carried the lysogenic phage C . The first methicillin-resistant strain carrying this phage had been isolated in 1974. The current methicillin-resistant S. aureus strains thus appear to form a distinct group that can be differentiated from those seen in earlier years.

Typing of methicillin resistant and susceptibleStaphylococcus aureus strains by ribosomal RNA gene restriction patterns using a biotinylated probe

“…The many common properties of the early MRSA isolates suggested a common clonal origin (2), although certain features observed in more recent MRSA might indicate otherwise (3,4). More recently, Lacey et al (5) suggested that one isolate with resistance to fewer antibiotics might be the primordial MRSA.…”

“…Many MRSA have proven difficult to type with the international basic set of phages and a number of alternative systems of typing have been evaluated, including experimental phages (4,8) and a variety of DNA or protein electrophoretic techniques (9)(10)(11)(12)(13)(14)(15).…”

Comparative Analysis of Multidrug-Resistant, Non-Multidrug-Resistant, and Archaic Methicillin-Resistant Staphylococcus aureus Isolates from Central Sydney, Australia

“…These early MRSA strains as well as subsequent MRSA strains have been preserved in the Staphylococcal Reference Collection at RPAH. Our phage typing data on strains from this collection suggested a population shift might have occurred in the late 1970s (33). We subsequently examined the collection genotypically and provided evidence to suggest that clonal displacement of the then-endemic strains by new strains of MRSA had occurred in this Australian hospital (6).…”

Epidemiological analysis of a methicillin-resistant Staphylococcus aureus outbreak using restriction fragment length polymorphisms of genomic DNA

“…All strains not typable showed weak lysis with the experimental phages 88 and 87M (Vickery et al, 1986).…”

“…Accurate identification of MRSA strains or types, and their carriers within a hospital, are of special importance in coping with these outbreaks, and a range of methods designed to do this have been described (Berke & Tilton, 1986 Smith & Berezny, 1986;Vickery et al, 1986).…”