Typing of Methicillin-Resistant <i>Staphylococcus aureus</i> in a University Hospital Setting by Using Novel Software for <i>spa</i> Repeat Determination and Database Management

TLDR

The spa gene of *Staphylococcus aureus* encodes protein A and is used for typing methicillin‑resistant *Staphylococcus aureus* (MRSA). The study aimed to investigate MRSA epidemiology at a German university hospital by sequencing the spa gene repeat region. Researchers analyzed 107 and 84 isolates collected over two 10‑ and 4‑month periods, determining spa repeats with the Ridom StaphType software and confirming representative types by multilocus sequence typing and pulsed‑field gel electrophoresis. The analysis revealed rapid clone dynamics, including the replacement of a predominant spa type by a clonally related variant, ten equally distributed unique spa types, and demonstrated that spa typing effectively tracks epidemic isolates and refutes suspected MRSA transmissions.

Abstract

ABSTRACT The spa gene of Staphylococcus aureus encodes protein A and is used for typing of methicillin-resistant Staphylococcus aureus (MRSA). We used sequence typing of the spa gene repeat region to study the epidemiology of MRSA at a German university hospital. One hundred seven and 84 strains were studied during two periods of 10 and 4 months, respectively. Repeats and spa types were determined by Ridom StaphType, a novel software tool allowing rapid repeat determination, data management and retrieval, and Internet-based assignment of new spa types following automatic quality control of DNA sequence chromatograms. Isolates representative of the most abundant spa types were subjected to multilocus sequence typing and pulsed-field gel electrophoresis. One of two predominant spa types was replaced by a clonally related variant in the second study period. Ten unique spa types, which were equally distributed in both study periods, were recovered. The data show a rapid dynamics of clone circulation in a university hospital setting. spa typing was valuable for tracking of epidemic isolates. The data show that disproval of epidemiologically suggested transmissions of MRSA is one of the main objectives of spa typing in departments with a high incidence of MRSA.