Beyond CC398: Characterisation of Other Tetracycline and Methicillin-Resistant Staphylococcus aureus Genetic Lineages Circulating in Spanish Hospitals.

Sara Ceballos,Carmen Torres,Carmen Aspiroz,Carmen Lozano,Emilia Cercenado,Paula Eguizábal,Allelen Campaña-Burguet,Laura Ruiz-Ripa,María Navarro,Jose Azcona-Gutiérrez,Carmen Martin,Myriam Zarazaga,Jorge Calvo,Luis Torres,Javier Castillo,The Study Group Of Clinical La-Mrsa ,Ana López-Calleja

doi:10.3390/pathogens11030307

Abstract

Tetracycline resistance (TetR) has been evidenced as a good phenotypic marker for detection of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) isolates of the clonal complex CC398. The aim of this study was to characterise a collection of 95 TetR-MRSA isolates, not belonging to the lineage CC398, that were obtained in a previous multicentre study, to detect other MRSA clonal complexes that could be associated with this phenotypic TetR marker. The TetR-MRSA isolates were recovered from 20 Spanish hospitals during 2016 and they were characterised to determine their antimicrobial resistance and virulence phenotypes/genotypes as well as the presence of the immune evasion cluster (IEC). A high proportion of isolates belonging to the CC1 lineage (46%) were observed, as well as to the CC5, CC8 and CC45 lineages (11% each one). Thirty-two different spa-types were identified, being predominantly CC1-t127 (40%) and CC45-t1081 (11%). The IEC system (with the gene scn as marker) was present in 73% of isolates and 16% produced the Panton Valentine leucocidin (PVL). A high proportion of MRSA-CC1 isolates were scn-negative (38.6%) and 52.9% of them were blaZ-negative. A multidrug resistance (MDR) phenotype was identified in 86% of MRSA isolates. The knowledge of other TetR-MRSA genetic lineages, in addition to CC398, is highly relevant, since most of them were MDR and some of them presented important virulence factors. Strains potentially associated with livestock (as the subpopulation CC1-t127-scn-negative) or with humans (as the CC45 lineage or the subpopulation CC1-scn-positive) have been found in this study. The use of tetracycline-resistance for detection, not only of CC398 but also of other LA-MRSA lineages should be tracked in the future.

Highlights

Staphylococcus aureus is a common bacterium in human and animal regular microbiota, present in the nose and on the skin
Thirty-two different spa-types were identified among the 95 TetR -methicillin-resistant S. aureus (MRSA) isolates analysed (Tables 1 and 2), with a40% of them belonging to spa-type t127, followed by t1081 (10.5%), t148 (6.3%), t002 (5.3%), and others with only one to three isolates per spa type
The spa types were ascribed to nine different clonal complexes (CC1, CC5, CC7, CC8, CC30, CC45, CC80, CC88, CC121), and to two sequence types (ST2625 and a Sequence Type (ST) registered as ST5427, a single-locus variant of ST2050 with a different aroE allele) (Tables 1 and 2)

Summary

Introduction

Staphylococcus aureus is a common bacterium in human and animal regular microbiota, present in the nose and on the skin. S. aureus can be an important opportunistic pathogen capable of causing anything from mild skin to life-threatening infections. S. aureus is able to acquire multiple antimicrobial resistance mechanisms, and standing out amongst them, methicillin-resistant S. aureus (MRSA) isolates because of its resistance to almost all β-lactams [1]. Different clonal lineages have been initially proposed to be directly related to the environment in which they are found. In this way, we classically found hospital-associated (HA) or community-acquired (CA) MRSA. We classically found hospital-associated (HA) or community-acquired (CA) MRSA Nowadays this line of distinction within groups is becoming more and more blurred

Objectives

Methods

Results

Discussion

Conclusion