• Korean Journal of Veterinary Research
• /
• v.39 no.6
• /
• pp.1218-1223
• /
• 1999

The purposes of this study are to examine seroprevalence of Mycoplasma hyopneumoniae infection in pigs of different age groups, and retrospectively determine if nursery depopulation (ND) could influence the seroprevalence of M hyopneumoniae infection in nurseries. Sera of 4, 8, 12, 16, and 20 weeks old pigs from 7 farms were first selected from a serum bank to examine serologic profiles for M hyopneumoniae infections. Availability of representative sera in the serum bank was a major criterion for farm selection. The sera were tested for M hyopneumoniae antibodies by an enzyme linked immunosorbent assay (ELISA) using Tween-20 extracted antigen. Serum samples were also selected from 15 of 34 swine farms that previously participated in a ND study. In order to evaluate M hyopneumoniae infection following ND, ELISA was performed with sera of 8~10 weeks old nursery pigs collected prior to and after ND for up to 12 months from the 15 farms. Serological profiles showed positive ELISA titers for 2 of 7 farms at 8 weeks, 4 of 7 farms at 12 weeks, 6 of 7 farms at 16 weeks, 6 of 6 farms at 20 weeks of age. Prior to ND, 11 of the 15 farms had positive titers in sera of 8~10 weeks old pigs. Sera of 8~10 weeks old pigs collected from 7 of the 11 farms (63.6%) were ELISA antibody negative for up to 12 months following ND. In conclusion, seroconversion to M hyopneumoniae was detected commonly between 10~16 weeks of age, indicating the occurrence of natural infection during the nursery age. The ND appeared to be an effective method to prevent M hyopneumoniae infection within the nursery pig in some farms.

• Korean Journal of Veterinary Research
• /
• v.46 no.3
• /
• pp.207-214
• /
• 2006

Mycoplasma gallisepticum (MG) continues to persist in many commercial layer farms in Korea,resulting in losses in egg production. Bacterins and live attenuated vaccines have been used for the prevention of losses caused by MG. One of these attenuated vaccines, MG 6/85 vaccine has been reported to be safe and efficacious in layers. However, MG 6/85 vaccine has not been evaluated for its safety and its efficacy in any commercial layer in Korea. Six-week-old specific pathogen-free (SPF) chickens were vaccinated with MG 6/85 vaccine by aerosol and were challenged with virulent MG R strain at 4 weeks after vaccination. The vaccinated group was able to resist challenge into the air sacs because the vaccinated group showed much less air sac lesion compared with the unvaccinated group. Each of two commercial layer farms was divided into vaccinated and unvaccinated groups. For each vaccinated gorup, MG 6/85 vaccine were sprayed at 17 week old on farm A and at 15 weeks old on farm B. Hen-day egg production, Hen-housed eggs, egg weight, mortality were evaluated until 50 week after vaccination.Compared with the unvaccinated group in each farm, the vaccinated group showed higher average egg production and egg weight, and higher hen-housed number. Results of this study are in agreement with other previous reports which demonstrated that MG 6/85 vaccine favorable effect on performance in commercial layers.

• Korean Journal of Veterinary Research
• /
• v.45 no.1
• /
• pp.55-61
• /
• 2005

Serum samples of 1,175 pigs from 148 Korean swine farms not using Mycoplasma hyopneumoniae (M. hyo) vaccines were collected for seroepidemiological study of M. hyo infection by indirect ELISA method. Informations of each farm were provided about province where the farm was located and season when blood samples were collected. Then, the selected farms were divided into farm units which had 5 serum samples according to production stages : sow, suckling piglet (<30 days old), nursery pig (30-70 days old), and growing pig (>70 days old). Seroprevalence of M. hyo infection according to production stages, province, and season was investigated by using ELISA-positve rate of the selected samples for each study. This study showed that 85.34% (78.94-91.78%, 95% CI) of farms were positive to M. hyo infection and 34.81% (32.09-37.53%, 95% CI) among pigs were sero-positive to M. hyo infection in Korean swine farms. In the study of seroprevalence by production stage, most farms had sows and growing pigs which were sero-positive to M. hyo infection (sow: 83.05%, growing pigs: 87.72%) and most pigs seemed to be naturally infected by M. hyo at 8-10 weeks of age. Also, M. hyo infection showed seasonal pattern that most pigs were infected in late fall to early winter. However, in the study of seroprevalence by province, there was no significant correlation between province and M. hyo sero-positive rate.

• Pediatric Infection and Vaccine
• /
• v.16 no.1
• /
• pp.92-96
• /
• 2009

Mycoplasma pneumoniae is a common cause of respiratory tract infections. M. pneumoniae infection frequently manifests with extrapulmonary symptoms such as central nervous system complications, skin or mucosal involvement, and gastrointestinal problems. However, cardiac complications associated with M. pneumoniae are rarely reported. We report the case of a 47-month-old girl who died of fulminant myocarditis associated with M. pneumoniae pneumonia.

• Allergy, Asthma & Respiratory Disease
• /
• v.6 no.6
• /
• pp.295-302
• /
• 2018

Purpose: It is thought that Mycoplasma pneumoniae infection is more prevalent and causes more severe pneumonia in school-age children and young adults than in preschool children; however, recent studies suggest that the infection may be underdiagnosed and more severe in preschool children. This study investigated the clinical characteristics of Mycoplasma pneumoniae pneumonia (MPP) and the risk factors of refractory MPP (RMPP) by age. Methods: We retrospectively reviewed the medical records of 353 children admitted due to MPP from January 2015 to December 2016. Demographics, clinical information, laboratory data and radiological findings were collected from all patients in this study. The patients were divided into 2 groups by the age of 6 years. Also, both preschool (< 6 years old) and school-age (${\geq}6$ years old) children were divided into RMPP and non-RMPP patients. Results: Total febrile days, febrile days before admission and the duration of macrolide antibiotic therapy were significantly longer in school-age children than in preschool children. School-age children had significantly greater risk of lobar consolidation (P=0.036), pleural effusion (P=0.001) and extrapulmonary complications (P=0.019). Necrotizing pneumonia and bronchiolitis obliterans tended to occur more frequently in preschool children than in school-age children. In both preschool and school-age children, lactate dehydrogenase (LDH) levels were significantly higher in RMPP patients than in non-RMPP patients. In preschool children, LDH > 722 IU/L (odds ratio [OR], 3.02; 95% confidence interval [CI], 1.44-6.50) and ferritin > 177 ng/mL (OR, 5.38; 95% CI, 1.61-19.49) were significant risk factors for RMPP, while LDH > 645 IU/L (OR, 4.12; 95% CI, 1.64-10.97) and ferritin > 166 ng/mL (OR, 5.51; 95% CI, 1.59-22.32) were so in school-age children. Conclusion: Clinical features of MPP were significantly different between preschool and school-age children. LDH and ferritin may be significant factors of RMPP in preschool and school-age children.

• Pediatric Infection and Vaccine
• /
• v.9 no.1
• /
• pp.85-94
• /
• 2002

Purpose: This study was performed for analysis of the results of polymerase chain reaction(PCR) and antibody test of Mycoplasma pneumoniae(M. pneumoniae) in children with symptoms of respiratory tract infection. In the cases of both positive antibody test and PCR for M. pneumoniae, the chest X-ray findings were assessed. Methods: The antibody test was done in 1,979 cases who have been admitted to Wonkwang university hospital department of pediatrics with symptoms of respiratory tract infection from January, 2000 to December, 2001. The positive antibody test was defined as titer of 1 : 80 and over 1 : 80. The PCR of M. pneumoniae were done in randomly selected 131 cases of respiratory tract infection. The chest X-ray findings were assessed in the cases of positive antibody test and PCR. Results: The numbers of cases of the positive antibody test for M. pneumoniae were 499 cases(25%). The PCR for M. pneumoniae were performed in 131 cases and the 45 cases(34%) were positive and 86 cases(66%) were negative. The 56 of 86 PCR negative cases were also negative antibody test, but 30 cases were positive antibody test. The 36 cases of 45 PCR positive cases were antibody positive, and 9 cases were antibody negative. The sputum Gram stain and culture for M. pneumoniae were negative in all the 499 cases of mycoplasma antibody positive respiratory infection. In these antibody positive 499 cases, the most common X-ray findings was interstitial pneumonic infiltration in 266 cases(53%), and pleural effusion were detected in 22 cases(4%), but nonspecific chest X-ray finding showed in 129 cases(26%). In PCR positive 45 cases, the most common chest X-ray finding was interstitial pneumonic infiltration in 32 cases(71%). Conclusion: The PCR for M. pneumoniae is more useful method for detection of mycoplasma infection in children with respiratory tract infection. The M. pneumoniae is a important etiologic agent for respiratory infection in children.

• Journal of Microbiology
• /
• v.44 no.1
• /
• pp.42-49
• /
• 2006

In this study, we describe our newly-developed sensitive two-stage PCR procedure for the detection of 13 common mycoplasmal contaminants (M. arthritidis, M. bovis, M. fermentans, M. genitalium, M. hominis, M. hyorhinis, M. neurolyticum, M. orale, M. pirum, M. pneumoniae, M. pulmonis, M. salivarium, U. urealyticum). For primary amplification, the DNA regions encompassing the 16S and 23S rRNA genes of 13 species were targeted using general mycoplasma primers. The primary PCR products were then subjected to secondary nested PCR, using two different primer pair sets, designed via the multiple alignment of nucleotide sequences obtained from the 13 mycoplasmal species. The nested PCR, which generated DNA fragments of 165-353 bp, was found to be able to detect 1-2 copies of the target DNA, and evidenced no cross-reactivity with the generated DNA of related microorganisms or of human cell lines, thereby confirming the sensitivity and specificity of the primers used. The identification of contaminated species was' achieved via the performance of restriction fragment length polymorphism (RFLP) coupled with Sau3AI digestion. The results obtained in this study furnish evidence suggesting that the employed assay system constitutes an effective tool for the disagnosis of mycoplasmal contamination in cell culture systems.

• Clinical and Experimental Pediatrics
• /
• v.59 no.3
• /
• pp.149-152
• /
• 2016

We report a case of a 5-year-old girl who developed left hemiparesis and left facial palsy, 6 days after the initiation of fever and respiratory symptoms due to pneumonia. Chest radiography, conducted upon admission, showed pneumonic infiltration and pleural effusion in the left lung field. Brain magnetic resonance imaging showed acute ischemic infarction in the right middle cerebral artery territory. Brain magnetic resonance angiography and transfemoral cerebral angiography revealed complete occlusion of the right middle cerebral artery. Mycoplasma pneumoniae infection was identified by a 4-fold increase in IgG antibodies to M. pneumoniae between acute and convalescent sera by enzyme-linked immunosorbent assay. Fibrinogen and D-dimer levels were elevated, while laboratory exams in order to identify other predisposing factors of pediatric stroke were all negative. This is the first reported pediatric case in English literature of a M. pneumoniae-associated cerebral infarction involving complete occlusion of the right middle cerebral artery.

• Korean Journal of Veterinary Service
• /
• v.31 no.3
• /
• pp.291-303
• /
• 2008

This study was performed to evaluate the effect of commercial swine mycoplasma vaccine (M+$Pac^{(R)}$, Schering-Plough Animal HealthCo.) at different vaccination time points. Total 139 piglets were moved to experimental farm after weaning and were randomly allocated to 3 treatment groups and 1 control group. Piglets of 3 treatment groups (A, B and C) were vaccinated twice at 1 and 3 weeks (A group), 3 and 5 weeks (B), and 6 and 8 weeks (C), respectively. All vaccinates showed higher antibody titers compared with nonvaccinates, and maintained to finish (P<0.001). Performance and RBC/WBC count showed no significant difference between groups. Vaccinates at 6-8 weeks showed better effect on decrease of clinical sign compared with vaccinates at 1-3 weeks and 3-5 weeks and nonvaccinates. Also, lung lesion assessment showed significant difference between vaccinates at 3-5 weeks and 6-8 weeks, and nonvaccinates and vaccinates at 1-3 weeks (P<0.05). Vaccinates at 3-5 score in comparison with other groups. In conclusion, these results suggested that vaccination at 3-5 weeks or later may be more effective than earlier vaccination.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.1
• /
• pp.153-158
• /
• 2008

A microchip-based capillary gel electrophoresis (MCGE) technique was developed for the ultra-fast detection and differentiation of Candidatus Mycoplasma haemominutum (Candidatus M. haemominutum, California strain) and Mycoplasma haemofelis (M. haemofelis, Ohio strain) in Korean feral cats through the application of programmed field strength gradients (PFSG) in a conventional glass double-T microchip. The effects of the poly (ethyleneoxide) (PEO) concentration and electric field strength on the separation of DNA fragments were investigated. The PCR-amplified products of Candidatus M. haemominutum (202-bp) and M. haemofelis (273-bp) were analyzed by MCGE within 75 s under a constant applied electric field of 117.6 V/cm and a sieving matrix of 0.3% PEO (Mr 8 000 000). When the PFSG was applied, MCGE analysis generated results 6.8-times faster without any loss of resolution or reproducibility. The MCGE-PFSG technique was also applied to eleven samples selected randomly from 33 positive samples. The samples were detected and differentiated within 11 s. The analysis time of the MCGE-PFSG technique was approximately 980-times faster than that using conventional slab gel electrophoresis.