|SONG, MINGHUI - Shanghai Institute For Food And Drug Control|
|LI, QIONGQIONG - Shanghai Institute For Food And Drug Control|
|FENG, ZHEN - Shanghai Institute For Food And Drug Control|
|LAN, LEFU - Shanghai Institute Of Pharmaceutical Industry|
|FAN, YILING - Shanghai Institute For Food And Drug Control|
|LIU, HAO - Shanghai Institute For Food And Drug Control|
|CHEN, DONGYING - Shanghai Institute Of Pharmaceutical Industry|
|YANG, MEICHENG - Shanghai Institute For Food And Drug Control|
Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/24/2019
Publication Date: 5/6/2019
Citation: Song, M., Li, Q., He, Y., Feng, Z., Lan, L., Fan, Y., Liu, H., Chen, D., Yang, M. 2019. A comprehensive multilocus sequence typing scheme for identification and genotyping of Staphylococcus strains. Foodborne Pathogens and Disease. 16(5):331-338. https://doi.org/10.1089/fpd.2018.2565.
Interpretive Summary: Staphylococcus aureus (produces an enzyme known as coagulase) and other Staphylococcus species that do not produce coagulase are important pathogens that can cause various diseases ranging from toxin-mediated illnesses, gastroenteritis, pneumonia, skin and tissue infections, and bacteremia. A DNA-based method known as multilocus sequence-based typing (MLST) was developed based on differences in six genes on the chromosome of S. aureus. By testing 172 Staphylococcus strains belonging to 18 different species, this method produced accurate results for species-level identification and genotyping. This new method overcomes limitations of other reported MLST methods that can only distinguish and identify a portion of the species, and thus the new MLST method allows for a more reliable and useful technique for genotyping both coagulase-positive and –negative staphylococcal species.
Technical Abstract: Increasing clinical significance of coagulase-negative staphylococci (CoNS) requires effective methods for species identification and genotyping of Staphylococcus. In this study, six new housekeeping genes (femA, ftsZ, gap, pyrH, rpoB, and tufA) with extensive allelic polymorphisms were identified for the development of a comprehensive multilocus sequence typing (MLST) scheme. Selected primers successfully amplified six loci from all of the 172 Staphylococcus strains belonging to 18 species. Sequence analysis of each locus (41 to 56 alleles) found higher nucleotide diversity than 16S rRNA (26 alleles). Phylogenetic analysis of the concatenated sequence (3054 bp) of the six loci provided accurate species-level identification and highly discriminatory typing for all the strains. Analysis of the multilocus allelic profile of the 172 isolates generated 95 sequence types (ST), suggesting high genetic diversity of the strains. For example, 30 S. aureus, 37 S. epidermidis, and 13 S. hominis strains were typed into 15, 21, and 9 STs, respectively. Compared with published MLST schemes which restrict on a few particular species, this new scheme not only achieved similar discrimination for typing S. aureus and S. hominis, but also provided sufficient discriminatory power for typing additional opportunistic species, such as S. cohnii, S. capitis, and S. warneri. Importantly, it overcomes the lack of efficient genotyping methods for coagulase-negative staphylococcal (CoNS) species.