Isolation and In Vitro cultivation of Lawsonia intracellularis from China

Xiao, Ni; Li, Jiannan; Li, Minxue; Zhao, Hong; Lin, Huixing; Fan, Hongjie

doi:10.1016/j.vetmic.2022.109457

Cited by 4 publications

(4 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The first group included fecal samples randomly collected from healthy pigs at different ages in 47 Chinese pig farms, and the investigation revealed a high farm positive rate of L. intracellularis [93.6% (95% CI: 65.3–94.4%)]. While few studies have reported the prevalence of L. intracellularis based on the detection of bacterial DNA on pig farms in China, two seroprevalence studies using ELISA assays detecting specific antibodies against L. intracellularis have demonstrated a high bacterial seropositivity (over 70%) ( 15 , 16 ). From another article published in Chinese, the farm positive rate of L. intracellularis on 21 pig farms in China was as high as 100% ( 21 ).…”

Section: Discussionmentioning

confidence: 99%

“…However, current data on the prevalence of L. intracellularis on Chinese pig farms is still limited. A recent study investigated 3,586 serum samples in eight major pig-producing provinces during 2019–2020 and revealed that 2,837 (79.1%, 95% CI: 77.7–80.4%) were seropositive for L. intracellularis ( 15 ). In an earlier study, examination of 1,060 serum samples from 14 commercial farms through China revealed a 57% (95% CI: 50–64%) seroprevalence of L. intracellularis ( 16 ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fecal PCR survey and genome analysis of Lawsonia intracellularis in China

Wang,

Wu,

Zhao

et al. 2024

Front. Vet. Sci.

View full text Add to dashboard Cite

Proliferative enteropathy caused by Lawsonia intracellularis is an important economic associated disease to pig industry, but the knowledge about the prevalence of L. intracellularis in pig farms in China is limited. In addition, there is no complete genome sequence available for L. intracellularis isolates from China. In this study, we developed a TaqMan qPCR for the screening of L. intracellularis by targeting the bacterial 16S rDNA gene. Laboratory evaluations revealed a good sensitivity and specificity on detecting L. intracellularis nucleic acid. Using this method, we investigated 891 fecal samples from apparently healthy pigs in 47 farms. The results demonstrated a screening positive rate of 37.3% (95% CI, 34.1–40.5%) for the samples, and a farm screening positive rate of 93.6% (95% CI, 65.3–94.4%). The screening positive rate at herd level ranged from 6.67% (95% CI, 0.2–31.9%) to 40% (95% CI, 38–79.6%), while at animal level, the highest screening positive rate was found in 12-week-old pigs [85.7% (95% CI, 67.3–96.0%)]. Investigation of 705 diarrheal or bloody feces from symptomatic pigs revealed that the highest positive rate was found in replacement gilts which was 37.18% (95% CI, 45.1–89.5%). Secondly, we conducted the complete genome sequence of a L. intracellularis PPE-GX01-2022 from China through PacBio sequencing. The genome of PPE-GX01-2022 consisted of a chromosome of 1,439,110 bp in length and three plasmids of 193,063, 39,799, and 27,067 bp, respectively. This genome encoded 1,428 predicted proteins, 44 tRNAs, and 6 rRNAs. Sequence comparisons demonstrated that the genome sequence of PPE-GX01-2022 was highly homologous to those of two isolates from US, and these three isolates shared 1,378 core genes. The screening results suggest a high prevalence rate of L. intracellularis in Chinese pig farms. In addition, the genome sequence of the Chinese isolate was highly homologous to those of the field isolates from the US.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fecal PCR survey and genome analysis of Lawsonia intracellularis in China

Wang,

Wu,

Zhao

et al. 2024

Front. Vet. Sci.

View full text Add to dashboard Cite

show abstract

“…Both vaccines have offered some protection degree to vaccinated animals [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. However, the production of these kinds of vaccines requires bacterial replication in eukaryotic cell culture, which implies high production costs associated with the particularly challenging microorganism isolation and in vitro culture conditions [ 18 , 19 ]. Additionally, these vaccines do not allow for the proper serological differentiation of vaccinated and infected animals [ 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

New Formulation of a Subunit Vaccine Candidate against Lawsonia intracellularis Increases Humoral and Cellular Immune Responses

Salazar,

Starck,

Villegas

et al. 2023

Vaccines

View full text Add to dashboard Cite

Previously, we designed a subunit vaccine candidate based on three L. intracellularis antigens with promising results in pigs. In this study, antigens were produced individually to achieve an even antigen ratio in the formulation. The emulsion characterization included the drop size and the mechanical and thermal stability. Immune response was evaluated by indirect and sandwich ELISAs, qPCR, and flow cytometry. The vaccine candidate’s safety was assessed by histopathology and monitoring the clinical behavior of animals. The average production yielded for the chimeric antigen as inclusion bodies was around 75 mg/L. The formulation showed mechanical and thermal stability, with a ratio Hu/Ho > 0.85 and a drop size under 0.15 nm. Antigens formulated at a ratio of 1:1:1 induced a significant immune response in inoculated pigs that persisted until the end of the experiment (week 14). The dose of 200 μg significantly activated cellular response measured by transcriptional and translational levels of cytokines. The cell proliferation assay revealed an increment of lymphocytes T CD4+ at the same dose. Animals gained weight constantly and showed proper clinical behavior during immunization assays. This research demonstrated the immunological robustness of the new subunit vaccine candidate against Porcine Proliferative Enteropathy evenly formulated with three chimeric antigens of L. intracellularis.

show abstract

“…By a blocking ELISA, the true within-herd prevalence of L. intracellularis antibodies in China was shown to be 77%, with fattening pigs, breeding sows, and boars in Northern or Southern parts having the highest frequency (Wu et al, 2014). This rate gained to 79.1% of 63 Chinese examined farms during 2019-2020 (Xiao et al, 2022). Another study, using the same technique, found high seroprevalence among high density pig population, with 71.7% and 88.9% in Western Australia and Queensland state, respectively; within the herds was 84.2% for the mean percentage of seropositive animals (Holyoake et al, 2010).…”

Section: Epidemiologymentioning

confidence: 99%

Seroprevalence of Lawsonia intracellularis antibody among swine herds in Thailand, December 2021-March 2022

Che

View full text Add to dashboard Cite

The gastrointestinal infectious diseases caused by bacteria have been a major problem in the Thai swine industry. Porcine proliferative enteropathy (PPE), also known as porcine ileitis, is an enteric infectious disease caused by�Lawsonia�intracellularis. Porcine ileitis has been an economic threat to the global pork production system due to various types of diarrheas. Serological diagnosis can be applied for determining pathogen-antibodies seroprevalence and the timing of�L. intracellularis�infection when introduced to the herd. A lack of serological data since 2009, as well as recent antibiotic usage restrictions, may have a negative impact on porcine ileitis seroprevalence in Thailand. Hence, the objective of this present study was to investigate the current serological status and the seroprevalence of antibodies against�L. intracellularis�in large-scale swine herds in Thailand using a commercial blocking enzyme-linked immunosorbent assay (ELISA). A total of 1,234 serums were sampled from 24 non-vaccinated commercial pig farms across Thailand as part of a monitoring program. The herd seroprevalence was obtained in a total of 22�out of 24 herds sampled, and the within-herd seroprevalence was 50.5%�(95% CI: 47.7-53.3%), with higher seropositivity detected in older animals. Furthermore, the most�Lawsonia-antibodies were found in the intensive larger farms in Northern Thailand. There was a significant difference in the within-herd seroprevalence between single-site and multiple-site production systems (P�< 0.001). Here, the finding confirmed that in the absence of the�L. intracellularis�vaccine, PPE seroprevalence in large commercial swine herds in Thailand was prevailing.

show abstract

Isolation and In Vitro cultivation of Lawsonia intracellularis from China

Cited by 4 publications

References 32 publications

Fecal PCR survey and genome analysis of Lawsonia intracellularis in China

Fecal PCR survey and genome analysis of Lawsonia intracellularis in China

New Formulation of a Subunit Vaccine Candidate against Lawsonia intracellularis Increases Humoral and Cellular Immune Responses

Seroprevalence of Lawsonia intracellularis antibody among swine herds in Thailand, December 2021-March 2022

Contact Info

Product

Resources

About