An assessment on DNA microarray and sequence-based methods for the characterization of methicillin-susceptible Staphylococcus aureus from Nigeria.

Adebayo O Shittu,Kenneth Okon,Lutz Von Müller,Mathias Herrmann,Georg Peters,Adeola Raji,Frieder Schaumburg,Ulla Ruffing,Omotayo Oyedara

doi:10.3389/fmicb.2015.01160

Abstract

Staphylococcus aureus is an important human pathogen causing nosocomial and community-acquired infections worldwide. In the characterization of this opportunistic pathogen, DNA microarray hybridization technique is used as an alternative to sequence based genotyping to obtain a comprehensive assessment on the virulence, resistance determinants, and population structure. The objective of this study was to characterize a defined collection of S. aureus isolates from Nigeria using the microarray technique, and to assess the extent that it correlates with sequence-based genotyping methods. The clonal diversity and genomic content of 52 methicillin-susceptible Staphylococcus aureus (MSSA) were investigated by spa typing, MLST and DNA microarray hybridization. More than half (55.8%) of these isolates were associated with clonal complexes (CCs) typically associated with methicillin-resistant S. aureus (MRSA) clones i.e., CC1, CC5, CC8, CC30, and CC45. Certain genes linked with virulence (hlgA and clfA) and adherence (ebpS, fnbA, sspA, sspB, and sspP) were detected in all isolates. A number of genes or gene clusters were associated with distinct clonal types. The enterotoxin gene cluster (egc) was linked with CC5, CC25, CC30, CC45, and CC121, enterotoxin H gene (seh) with CC1, exfoliative toxin D gene (etd) with CC25 and CC80, and the epidermal cell differentiation inhibitor B gene (edinB) with CC25, CC80, and CC152. The excellent agreement between data from DNA microarray and MLST in the delineation of Nigerian MSSA isolates indicates that the microarray technique is a useful tool to provide information on antibiotic resistance, clonal diversity and virulence factors associated with infection and disease.

Highlights

Staphylococcus aureus is implicated in a variety of human infections with high rates of morbidity and mortality (Lowy, 1998; Corey, 2009)
We observed a complete agreement between DNA microarray analysis and Multilocus sequence typing (MLST) in the delineation of the isolates (Table 1), showing that the hybridization profile could be used to predict the lineages
The heterogeneous and divergent nature of the isolates observed in this study provided evidence on the overall higher diversity of Methicillin susceptible Staphylococcus aureus (MSSA) compared with methicillin-resistant S. aureus (MRSA) (Deurenberg and Stobberingh, 2008; Goering et al, 2008; Ghasemzadeh-Moghaddam et al, 2011; Ruffing et al, 2012; Blomfeldt et al, 2013; Rasmussen et al, 2013, 2014)

Summary

Introduction

Staphylococcus aureus is implicated in a variety of human infections with high rates of morbidity and mortality (Lowy, 1998; Corey, 2009). Recent studies in Cameroon (Kihla et al, 2014), Egypt (Ahmed et al, 2014), Gabon (Alabi et al, 2013), Nigeria (Jido and Garba, 2012; Oladeinde et al, 2013), South Africa (Groome et al, 2012; Naidoo et al, 2013), and Tanzania (Kayange et al, 2010; Mhada et al, 2012) have identified S. aureus as the main etiological agent for various infections in Africa This species has been recognized as one main cause of community-acquired neonatal sepsis in Africa (Waters et al, 2011). These studies clearly establish the important role of this major human pathogen in tropical Africa

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Conclusion