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Updated: Feb 19, 2026
Identification of Rare Bacterial Pathogens by 16S rRNA Gene Sequencing and MALDI-TOF MS
Published on: July 11, 2016
Accuracy of PCR targeting different markers for Staphylococcus aureus identification: a comparative study using
Mauro M Saraiva1,2,3,4,5, Candice M De Leon1,2,3,4,5, Silvana C Santos1,2,3,4,5
1Departments of Animal Sciences (Saraiva, De Leon, Santos, Oliveira), College of Agricultural Sciences, Federal University of Paraiba, Areia, Paraíba, Brazil.
Abstract:
Staphylococcus aureus is considered a major pathogen in veterinary and human medicine, and the emergence of multidrug-resistant strains, such as livestock-associated methicillin-resistant S. aureus, means that reliable, inexpensive, and fast methods are required to identify S. aureus obtained from animal sources. We tested the accuracy of a PCR targeting the genes femA, nuc, and coa in identifying S. aureus from animals. A total of 157 Staphylococcus spp. isolates were examined by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry; 18 different Staphylococcus species were identified. Of 68 S. aureus isolates, the genes femA, nuc, and coa were found in 61, 53, and 32 isolates, respectively. Considering MALDI-TOF as the gold standard, the PCR assays targeting all 3 genes showed 100% specificity; the sensitivity values were 89.7, 77.9, and 47.0% for femA, nuc, and coa, respectively. Sensitivity was 100% when femA and nuc markers were targeted simultaneously. These results confirm PCR as an accurate method to identify S. aureus species from animal sources and strongly suggest the simultaneous use of primers targeting femA and nuc genes.
Insights
Accurate identification of Staphylococcus aureus from animal sources is crucial. A PCR assay targeting the femA and nuc genes simultaneously offers a reliable and sensitive method for detecting this important pathogen.
Area of Science:
- Veterinary Microbiology
- Molecular Diagnostics
- Food Safety
Background:
- Staphylococcus aureus is a significant pathogen in both human and veterinary medicine.
- The rise of multidrug-resistant strains, like livestock-associated methicillin-resistant S. aureus (LA-MRSA), necessitates rapid and accurate identification methods.
- Identifying S. aureus from animal sources is critical for controlling its spread and impact.
Purpose of the Study:
- To evaluate the accuracy of a Polymerase Chain Reaction (PCR) assay for identifying Staphylococcus aureus from animal isolates.
- To assess the efficacy of targeting specific genes (femA, nuc, and coa) for S. aureus detection.
- To determine the optimal combination of PCR targets for reliable S. aureus identification.
Main Methods:
- Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry was used for species identification (gold standard).
- A total of 157 Staphylococcus spp. isolates, including 68 S. aureus strains, were analyzed.
- PCR assays were performed targeting the femA, nuc, and coa genes individually and in combination.
Main Results:
- PCR assays demonstrated 100% specificity for S. aureus detection when targeting all three genes.
- Individual gene sensitivities were 89.7% for femA, 77.9% for nuc, and 47.0% for coa.
- Simultaneous targeting of femA and nuc genes achieved 100% sensitivity, confirming S. aureus presence.
Conclusions:
- PCR is a highly accurate method for identifying Staphylococcus aureus from animal sources.
- The combined use of primers targeting the femA and nuc genes provides a sensitive and specific diagnostic approach.
- This molecular method is valuable for surveillance and control of S. aureus in animal populations.
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01:08Matrix-Assisted Laser Desorption Ionization (MALDI)