Alterations in phage-typing patterns in vancomycin-intermediate Staphylococcus aureus

Abstract

The ability of phage-typing and SmaI chromosomal RFLPs to conclude appropriate strain relatedness between a collection of 12 well-characterized in vitro-selected vancomycinintermediate Staphylococcus aureus (VISA) strains and their seven vancomycin-susceptible parent strains is reported. Generally, no SmaI RFLP alterations were observed in VISA strains when they were compared with their respective parent strains, and clonal relationships between isogenic strains were clearly evident. Unlike the SmaI RFLP results, parent strains and VISA derivatives generally did not share similar phage-typing profiles. Depending on the phage set investigated, some VISA strains even became untypable by this method. Loss of phage infectivity is probably due to cell wall (phage receptor) alterations that are expressed by the VISA strains investigated. Collectively, these findings indicate that inappropriate relationships between VISA and vancomycinsusceptible parents might be drawn if only phage-typing and antibiotic susceptibility are utilized to determine epidemiological relationships.

The Role of β-Glycosylated Wall Teichoic Acids in the Reduction of Vancomycin Susceptibility in Vancomycin-Intermediate Staphylococcus aureus

“…Both strains showed a strong reduction in phage susceptibility. A contrast in phage typeability in isogenic VISA/VSSA pairs was also observed by Gustafson et al ( 39 ). In our study, the reason for the absence of phage typeability of S. aureus VC40 was the difference in the glycosylation pattern of the WTA.…”

Cell Wall Composition and Decreased Autolytic Activity and Lysostaphin Susceptibility of Glycopeptide-Intermediate Staphylococcus aureus

“…SmaI chromosomal restriction fragment length pulsed-field gel electrophoresis studies have confirmed the close relationship between the parent and GISA strains within each set of strains (17). However, some loss of phage typeability was noted in GISA strains compared to that of their parent strains.…”

“…Teichoic acid comprises part of the S. aureus phage receptor site (7). Gustafson et al (17) have reported a decrease in the number of phage types to which the BB270, 13136 p Ϫ m ϩ , and COL GISA strains were susceptible compared to the numbers for their parent strains. This might involve decreased wall teichoic acid levels and the severe autolytic deficiency in the GISA strains (see below), which may interfere with phage lysis.…”

sarA inactivation reduces vancomycin-intermediate and ciprofloxacin resistance expression by Staphylococcus aureus

“…The unrelated laboratory-derived isogenic VISA and parent strain sets have been described previously [20,33]. Laboratory VISA were derived from BB270 (a heterogeneous MRSA transductant) [34], COL (a homogenous MRSA) [35] and strain 13136p−m+, which is one of the first MRSA strains described [36].…”