Dissemination of Two Methicillin-Resistant Staphylococcus aureus Clones Exhibiting Negative Staphylase Reactions in Intensive Care Units

Abstract

From December 1997 to March 1998, 25 methicillin-resistantStaphylococcus aureus (MRSA) isolates exhibiting negative Staphylase (Oxoid Ltd., Basingstoke, England) reactions were identified from various clinical specimens from 13 patients in six intensive care units (ICUs) or in wards following a stay in an ICU at the National Taiwan University Hospital. The characteristics of these isolates have not been previously noted in other MRSA isolates from this hospital. Colonies of all these isolates were grown on Trypticase soy agar supplemented with 5% sheep blood and were nonhemolytic and unpigmented. Seven isolates, initially reported as Staphylococcus haemolyticus (5 isolates) and Staphylococcus epidermidis (2 isolates) by the routine identification scheme and with the Vitek GPI system (bioMerieux Vitek, Inc., Hazelwood, Mo.), were subsequently identified as S. aureus by positive tube coagulase tests, standard biochemical reactions, and characteristic cellular fatty acid chromatograms. The antibiotypes obtained by the E test, coagulase types, restriction fragment length polymorphism profiles of the staphylococcal coagulase gene, and random amplified polymorphic DNA patterns generated by arbitrarily primed PCR of the isolates disclosed that two major clones disseminated in the ICUs. Clone 1 (16 isolates) was resistant to clindamycin and was susceptible to trimethoprim-sulfamethoxazole (TMP-SMZ) and was coagulase type II. Clone 2 (eight isolates) was resistant to clindamycin and TMP-SMZ and was coagulase type IV. These two epidemic clones from ICUs are unique and underline the need for caution in identifying MRSA strains with colonial morphologies not of the typical type and with negative Staphylase reactions.

Combatting bacterial infections by killing persister cells with mitomycin C

“…We used this in vitro wound model to test MMC activity against cultures of EHEC, S. aureus and P. aeruginosa PAO1 as well as a co‐culture of S. aureus and P. aeruginosa PAO1. Our strain of S. aureus is coagulase‐positive (Hsueh et al ., ), causing the medium to form a jelly‐like mass consisting of insoluble fibrin (Zajdel et al ., ). Cultures were grown statically so that coagulated plasma served as a scaffold for bacterial growth (DeLeon et al ., ) in cultures containing S. aureus , while biofilms formed at surface interfaces served as scaffolds for bacterial growth in cultures without S. aureus .…”

Catheter-related bacteraemia and infective endocarditis caused by Kocuria species

“…Random amplified polymorphic DNA (RAPD) patterns of all isolates of Kocuria species generated by arbitrarily primed PCR were as described previously [10]. Two arbitrary oligonucleotide primers: M13 (5′‐GAGGGTGGCGGTTCT‐3′) (Gibco BRL Products, Gaithersburg, MD, USA) and H12 (5′‐ACGCGCATGT‐3′) (Operon Technologies, Inc., Alameda, CA, USA) were used.…”

“…The arbitrarily primed PCR analyses of these isolates were performed in duplicate. Interpretation of the RAPD patterns was performed as previously described [10].…”

PCR Assay for Species-Specific Identification of Bacteroides thetaiotaomicron

“…Subsequently, the primers were designed based on the sequences of this fragment and a PCR assay was set up. RAPD analysis has been used mostly for intraspecies discrimination in epidemiological studies (8,9). However, PCR assays based on the primers designed from conserved fragments generated by RAPD have been previously reported (7,12,14,17).…”