Prevalence of Ureaplasma species among patients at a tertiary hospital in China: a 10-year retrospective study from 2013 to 2022.

BACKGROUND: Ureaplasma species are common pathogens of the urogenital tract and can cause a range of diseases. Unfortunately, there is still a scarcity of large-scale and cross-sectional studies on the prevalence of Ureaplasma species in China to clarify their epidemic patterns. METHODS: This study retrospectively analyzed the data of 18667 patients who visited Peking Union Medical College Hospital for showing various symptoms of (suspected) Ureaplasma species infection during the period 2013-2022. The overall prevalence of Ureaplasma species was calculated, and subgroup analyses were conducted in view of gender, age, specimen types, and diagnosis in every year within the period studied. Furthermore, previous literature that reported on the prevalence of Ureaplasma species in various regions of China was searched and summarized. RESULTS: The overall positive rate of Ureaplasma species in this study reached 42.1% (7861/18667). Specifically, the prevalence of Ureaplasma species was significantly higher in female patients, while the highest detection rate was found in the 21-50 age group. From 2013 to 2022, there were no significant differences in positive rates of Ureaplasma species among years. However, the detection rate of Ureaplasma species was decreased in COVID-19 period (2020-2022) compared to pre-COVID-19 period (2017-2019). In view of the distribution of patients, outpatients predominated, but the detection rate was lower than inpatients. Urine was the most common specimen type, while cervical swabs had the highest detection rate of Ureaplasma species. When grouped by diagnosis, the highest positive rate of Ureaplasma species was seen in patients with adverse pregnancy outcomes and the lowest rate in patients with prostate disease. The previous literature, although heterogeneous, collectively suggested a high prevalence of Ureaplasma species in China. CONCLUSIONS: Our study has shown that Ureaplasma species have reached a significant prevalence in China and demands adequate attention.

An Attenuated Highly Pathogenic Chinese PRRS Viral Vaccine Confers Cross Protection to Pigs against Challenge with the Emerging PRRSV NADC30-Like Strain.

A novel PRRSV strain was isolated in China that was genetically similar to the NADC30 strain which is reported to have spread throughout China. The objective of the present study was to evaluate the cross-protective efficacy of the live vaccine TJM-F92 in young pigs against challenge with a NADC30-like strain, HN201605. Twenty-five PRRSV- and antibody-free pigs were randomly divided into the following five groups: Vac/ChA, Unvac/ChA, Vac/ChB, Unvac/ChB and the mock. The pigs in groups Vac/ChA and Vac/ChB were inoculated intramuscularly with 1 mL TJM-F92 (105.0 TCID50/mL). At 28 days post vaccination (0 days post challenge), groups Vac/ChA and Unvac/ChA were inoculated intranasally with 104.5 TCID50/mL PRRSV strain TJ F3 (2 mL/pig), while groups Vac/ChB and Unvac/ChB were inoculated, using the same route, with the same dose of the NADC30-like strain HN201605 F3. Protective effects of the PRRSV strain were observed in all pigs in the Vac/ChA and Vac/ChB groups. Neither high fever nor signs of clinical disease were observed through the experiment in these groups, whereas pigs in Unvac/ChA group exhibited serious clinical symptoms, pathological lesions, and weight loss. In Unvac/ChB group, pigs developed milder clinical symptoms, which demonstrated that the NADC30-like strain HN201605 had moderate pathogenicity. The results suggest that the MLV vaccine strain TJM-F92 is an effective and safe vaccine candidate for use in China.

Isolation, molecular characterization and an artificial infection model for a variant porcine epidemic diarrhea virus strain from Jiangsu Province, China.

Porcine epidemic diarrhea virus (PEDV) is a causative agent of porcine intestinal disease, which causes vomiting, diarrhea, and dehydration in piglets. PEDV is associated with the most severe pathogenesis in one-week-old piglets, with mortality rates reaching 100%. A PEDV strain was isolated from the intestinal tract of diarrheic piglets from a pig farm in Jiangsu Province in March 2016, termed the JS201603 isolate. The isolated virus was confirmed to be PEDV via RT-PCR, electron microscopy, a cytopathic effect assay and sequence analysis. The S and ORF3 genes of the JS201603 isolate were sequenced, revealing that the S gene was associated with a 15-base insertion at 167 nt, 176 - 186 nt, and 427 - 429 nt, as well as a six-base deletion in 487 - 492 nt, indicating that it was a current epidemic variant compared with the classical strain, CV777. No deletion occurred between 245 - 293 nt of the ORF3 gene in the JS201603 isolate compared with the vaccine isolates YY2013 and SQ2014. An experimental infection model indicated that the piglets in the challenge group successively developed diarrhea, exhibiting yellow-colored loose stools with a foul odor. The piglets in the JS201603 isolate challenge group displayed reduced food consumption, lost weight, and in severe cases even died. No abnormalities were observed in the control group. The JS201603 variant isolated in this study contributes to the evolutionary analysis of diarrhea virus. The experimental infection model has established a foundation for further studies on vaccine development.

Pathological and immunological characteristics of piglets infected experimentally with a HP-PRRSV TJ strain.

BACKGROUND: Porcine reproductive and respiratory syndrome (PRRS) remains a major threat to swine industry all over the world. The aim of this study was to investigate the mechanism of pathogenesis and immune responses caused by a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV). RESULTS: All piglets experimentally infected with a HP-PRRSV TJ strain virus developed typical clinical signs of PRRS. The percentages of CD3+, CD4+, and CD8+ lymphocytes significantly decreased in the infected group as compared to the uninfected control animals (p < 0.01). Total WBC dropped in the infected animals during the experiment. The level of ELISA antibody against PRRSV increased in 7-10 days after infection and then started to decline. Pathological observations demonstrated various degree lesions, bleeding and necrosis in the lungs of the infected piglets. CONCLUSIONS: These results clearly indicated that HP-PRRSV TJ strain infection would activate host humoral immune response at the early period post infection and cause severe pathological damages on lungs and inhibit cellular immune response after infection.

Isolation, molecular characterization and evaluation of the pathogenicity of a porcine rotavirus isolated from Jiangsu Province, China.

In this study, a porcine rotavirus was isolated from a fecal sample from a diarrheic piglet in Jiangsu Province, China. Rotavirus-specific cytopathic effects were observed after 12 blind passages on MA-104 cells, yielding a virus titer of 10(6.125) TCID50/ml. By applying an 80 % nucleotide cutoff value and the RotaC(2.0) automated genotyping tool, the Vp4 genotype of the new isolate was identified as P[7]. The Vp7 genotype was identified as G[9], lineage VI, and sublineage c. Experimentally infected piglets showed severe diarrhea symptoms 16-24 h post-inoculation, indicating that this new porcine rotavirus isolate is a pathogenic strain.

Complete genome sequence of a highly pathogenic porcine reproductive and respiratory syndrome virus NM1 strain from northern China.

NM1 is a highly pathogenic North American-type porcine reproductive and respiratory syndrome virus (PRRSV). The complete genome sequence shows that NM1 shares high sequence identity (99.2 to 99.4%) to other HP-PRRSV isolates, containing two discontinuous deletions, a 1-amino-acid deletion at position 481 and a 29-amino-acid deletion at positions 533 to 651, in nonstructural protein 2.

Evaluation of the efficacy of an attenuated live vaccine against highly pathogenic porcine reproductive and respiratory syndrome virus in young pigs.

Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) is characterized by high fever and high mortality in pigs of all ages and has severely affected the pork industry of China in the last few years. An attenuated HP-PRRSV strain, TJM, was obtained by passaging HP-PRRSV strain TJ on MARC-145 cells for 92 passages. Porcine reproductive and respiratory syndrome virus (PRRSV)- and antibody-free pigs were inoculated intramuscularly with TJM (10(5.0) 50% tissue culture infective doses [TCID(50)]) and challenged at 28, 60, 120, and 180 days postimmunization (dpi). The results showed that 5/5, 5/5, 5/5, and 4/5 immunized pigs were protected from the lethal challenge and did not develop fever and clinical diseases at each challenge, respectively. Compared to control pigs, vaccinated pigs showed much milder pathological lesions and gained significantly more weight (P < 0.01). Sequence analysis of different passages of strain TJ showed that the attenuation resulted in a deletion of a continuous 120 amino acids (aa), in addition to the discontinuous 30-aa deletion in the nsp2 region. The analysis also demonstrated that the 120-aa deletion was genetically stable in vivo. These results suggested that HP-PRRSV TJM was efficacious against a lethal challenge with a virulent HP-PRRSV strain, and effective protection could last at least 4 months. Therefore, strain TJM is a good candidate for an efficacious modified live virus vaccine as well as a useful molecular marker vaccine against HP-PRRSV.

Mutations in the genome of the highly pathogenic porcine reproductive and respiratory syndrome virus potentially related to attenuation.

A live-attenuated highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) virus (HP-PRRSV) TJM vaccine strain was derived from the HP-PRRSV TJ strain by passage 92 times in the African green monkey kidney epithelial cell line Marc-145. We found that the virulence of the TJ strain to piglets was decreased greatly from passage 19. To identify mutations associated with attenuation of the TJM vaccine strain, we determined the nucleotide changes that arose during Marc-145 passage of the HP-PRRSV TJ virus. The TJM strain contains a 360 nucleotide (120 amino acids) deletion and a 118 nucleotide mutation that resulted in 48 amino acid changes. Analysis of the complete nucleotide sequences of intermediate passage-level viruses F19, F46 and F78 showed that 31 (64.6%) of the 48 amino acid mutations occurred in F19, 7 (14.6%) occurred in F46, 7 (14.6%) occurred in F78 and 3 (6.3%) occurred in F92. The 120 amino acid deletion occurred from F19 to TJM. Therefore, we hypothesized that the 31 amino acid mutations distributed in nsp1ß, nsp2-nsp5, nsp7, nsp9, nsp10, GP4 and GP5 and the continuous 120 amino acid deletion in the nsp2 region from F19 provide a strong potential molecular basis for the observed attenuated phenotype.