Rapid Visual Detection of Highly Pathogenic Streptococcus suis Serotype 2 Isolates by Use of Loop-Mediated Isothermal Amplification

Abstract

bStreptococcus suis serotype 2 (S. suis 2) is an important zoonotic pathogen that causes considerable economic losses to the pig industry and significantly threatens public health worldwide. The highly pathogenic S. suis 2, which contains the 89K pathogenicity island (PAI), has caused large-scale outbreaks of infections in humans, resulting in high mortality rates. In this study, we established two loop-mediated isothermal amplification (LAMP)-based assays that can rapidly detect S. suis 2 and the 89K PAI and can be performed simultaneously under the same conditions. Further, based on the findings of these two LAMP assays and using the same set of serially diluted DNA samples, we compared the sensitivities of different LAMP product detection methods, including SYBR green detection, gel electrophoresis, turbidimetry, calcein assays, and hydroxynaphthol blue detection. The results suggest that target genes can be amplified and detected within 48 min under 63°C isothermal conditions. The sensitivity of tests for S. suis 2 detection varies between detection methods and reaction systems, indicating that for each LAMP reaction system, multiple detection methods should be performed to select the optimal one. The sensitivities of the optimized methods (7.16 copies/reaction) in the present study were identical to those of the real-time PCR assay, and the test results for reference strains and clinical samples showed that these LAMP systems have high specificities. Thus, since the LAMP systems established in this study are simple, fast, and sensitive, they may have good clinical potential for detecting the highly pathogenic S. suis 2.

Catabolite control protein A is an important regulator of metabolism in Streptococcus suis type 2

“…However, it was determined that PLS-DA should be used as the main model for analyzing the metabolomics samples as previously described (13). Based on the PLS-DA models, the native S. suis type 2 and CcpA mutant strains were successfully discriminated, with an R2X value of 0.439 and a Q2 value of 0.924 in the electrospray ionization (ESI)+ model using variable importance in the projection (VIP) of the first and second principal components (t [1] and t [2], respectively). An R2X value of 0.452 and a Q2 value of 0.878 were obtained with the ESI-model (Fig.…”

“…Streptococcus suis (S. suis) type 2 is an important Gram-positive bacterial pathogen of pigs that causes large economic losses in the meat industry, has a high rate of incidence and induces mortality worldwide (1,2).…”

Development of loop-mediated isothermal amplification to detect Streptococcus suis and its application to retail pork meat in Japan

“…After optimization, LAMP SS was carried out at 60°C for 60 min, followed by heating at 80°C for 5 min to inactivate the reaction using T100™ Thermal Cycler (Bio-Rad, Hercules, CA). LAMP 2J was performed as described previously (Zhang et al, 2013). A negative control, the same reaction mixture with distilled water instead of the DNA template, was included in each run.…”

“…However, it requires a 90-min procedure for enzyme digestion of the amplified product and two rounds of gel electrophoresis to identify bacterial species, and also cannot determine the bacterial serotypes. Zhang et al (2013) recently developed LAMP targeting cps2J, which we hereafter refer to as LAMP 2J , and salK. However, these 2 genes are only specific to a limited clonal group of highly pathogenic S. suis.…”

Diagnostik Antijen Olarak Rekombinant Sao-M Protein Kullanılarak Streptococcus suis’in Tanısı Amacıyla PPA-ELİSA Geliştirilmesi

“…Due to its fast spread and high mortality, S. suis infection has become a huge threaten for economic and healthy [27] . Therefore, serological surveillance is useful in determining the infection status and could play an important role in the control of S. suis in both pigs and humans [28] .…”