• Title, Summary, Keyword: reinfection

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Evolution of Genetic Polymorphisms of Plasmodium falciparum Merozoite Surface Protein (PfMSP) in Thailand

  • Kuesap, Jiraporn;Chaijaroenkul, Wanna;Ketprathum, Kanchanok;Tattiyapong, Puntanat;Na-Bangchang, Kesara
    • The Korean Journal of Parasitology
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    • v.52 no.1
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    • pp.105-109
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    • 2014
  • Plasmodium falciparum malaria is a major public health problem in Thailand due to the emergence of multidrug resistance. The understanding of genetic diversity of malaria parasites is essential for developing effective drugs and vaccines. The genetic diversity of the merozoite surface protein-1 (PfMSP-1) and merozoite surface protein-2 (PfMSP-2) genes was investigated in a total of 145 P. falciparum isolates collected from Mae Sot District, Tak Province, Thailand during 3 different periods (1997-1999, 2005-2007, and 2009-2010). Analysis of genetic polymorphisms was performed to track the evolution of genetic change of P. falciparum using PCR. Both individual genes and their combination patterns showed marked genetic diversity during the 3 study periods. The results strongly support that P. falciparum isolates in Thailand are markedly diverse and patterns changed with time. These 2 polymorphic genes could be used as molecular markers to detect multiple clone infections and differentiate recrudescence from reinfection in P. falciparum isolates in Thailand.

Acquired resistance of rock bream (Oplegnathus fasciatus) against rock bream iridovirus (RBIV) through undergoing low water temperature period

  • Zenke, Kosuke;Yoon, Ki Joon;Kim, Min Sun;Choi, Seung Hyuk;Kim, Ki Hong
    • Journal of fish pathology
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    • v.27 no.2
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    • pp.85-89
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    • 2014
  • Water temperature is a key environmental factor controlling the epizootics of viral diseases in fish. High water temperature is associated with the rapid spread of rock bream iridovirus (RBIV) disease and with high mortality of RBIV infected fish. Although protection of fish against iridoviral disease by active immunization has been reported, little information is available concerning whether fish survived from an epizootic of iridoviral disease can naturally acquire resistance against the viral disease. In the present study, we have demonstrated that juvenile rock bream, which survived from a natural epizootic of RBIV, acquired resistance against recurrence or reinfection of RBIV, and this resistance was established during the subsequent low water temperature period. Furthermore, the possible involvement of the adaptive humoral immune response in the resistance of the juvenile rock bream was suggested by in vivo neutralization experiment.

Recurrent Pseudomonas aeruginosa Infection in Chronic Lung Diseases: Relapse or Reinfection?

  • Yum, Ho-Kee;Park, I-Nae;Shin, Bo-Mun;Choi, Soo-Jeon
    • Tuberculosis and Respiratory Diseases
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    • v.77 no.4
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    • pp.172-177
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    • 2014
  • Background: Pseudomonas aeruginosa infection is particularly associated with progressive and ultimately chronic recurrent respiratory infections in chronic obstructive pulmonary disease, bronchiectasis, chronic destroyed lung disease, and cystic fibrosis. Its treatment is also very complex because of drug resistance and recurrence. Methods: Forty eight cultures from 18 patients with recurrent P. aeruginosa pneumonia from 1998 to 2002 were included in this study. Two or more pairs of sputum cultures were performed during 2 or more different periods of recurrences. The comparison of strains was made according to the phenotypic patterns of antibiotic resistance and chromosomal fingerprinting by pulsed field gel electrophoresis (PFGE) using the genomic DNA of P. aeruginosa from the sputum culture. Results: Phenotypic patterns of antibiotic resistance of P. aeruginosa were not correlated with their prior antibiotic exposition. Fifteen of 18 patients (83.3%) had recurrent P. aeruginosa pneumonia caused by the strains with same PFGE pattern. Conclusion: These data suggest that the most of the recurrent P. aeruginosa infections in chronic lung disease occurred due to the relapse of prior infections. Further investigations should be performed for assessing the molecular mechanisms of the persistent colonization and for determining how to eradicate clonal persistence of P. aeruginosa.

SEM STUDY ON THE BACTERIAL ADHESION TO THE DENTIN OF THE ROOT CANAL (미생물의 근관내 상아질 부착에 대한 주사전자현미경적 연구)

  • Jeong, Sang-Kyun;Oh, Tae-Seok;Bae, Kwang-Shik
    • Restorative Dentistry and Endodontics
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    • v.25 no.1
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    • pp.116-122
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    • 2000
  • On the instrumented root canal wall, amorphous, irregular smear layer can be observed with Scanning Electron Microscope(SEM). The purpose of this study was to evaluate the effect of the presence or absence of smear layer on the adhesion of Staphylococcus aureus to the dentin of the root canal. Human incisors, extracted within 7 days, with no caries, no fracture, no calcification of canal, were selected. After cutting crown portion at cemento-enamel junction, root canal preparation was done by modified crown-down technique using Profile and Gates - Glidden Drill. During canal preparation, 10ml physiologic saline solution(group1&3) or 10ml 3.5% NaOCl(group2&4) was used as irrigation solution. And 10ml physiologic saline solution(group1&3) or 10ml 0.5M EDTA(group2&4) was applicated for final flush. After vertical sectioning and ethylene oxide gas sterilization, samples(group1&2) were immersed into BHIYHM broth inoculated with Staphylococcus aureus (ATCC 31153) and incubated for 3hrs at $37^{\circ}C$. All samples were prepared for and observed with SEM(JEOL JSM840S). The data were analyzed by Mann-Whitney rank sum test. The conclusions are as follows ; 1. Smear layer covers entire root canal surface after root canal preparation. 2. Smear layer has been removed away and the entrances of dentinal tubules have opened widely, when applying 0.5M EDTA and 3.5% NaOCl. 3. A significantly higher number of bacteria were adhered to the root canal dentin without smear layer(p<0.0001). 4. Smear layer produced during root canal preparation impedes bacterial adhesion and colonization to dentin matrix, therefore inhibits canal reinfection.

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Endocarditis with Intracardiac Migration of Transvenous Permanent Pacing Lead - 1 Case Report - (영구 경정맥 심박조율도관의 심장내 이동과 동반된 심내막염 - 1례 보고 -)

  • Ku, Gwan-Woo;Kang, Shin-Kwang;Won, Tae-Hee;Kim, Si-Wook;Yu, Jae-Hyun;Na, Myung-Hoon;Lim, Seung-Pyung;Lee, Young
    • The Korean Journal of Thoracic and Cardiovascular Surgery
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    • v.35 no.11
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    • pp.831-834
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    • 2002
  • When any part of the pacemaker system is infected, all pacemaker hardware should be removed, because reinfection rates of 51% to 77% have been noted in patients whose infected pacemaker system has been only partially explanted. The removal of infected leads during cardiopulmonary bypass prevents mechanical injury as well as the spread of infection and vegetation. We report one case of endocarditis by staphylococcus aureus with infected transvenous pacing lead which was migrated into the heart from the left subclavian vein. We removed the migrated pacing lead and vegetation under cardiopulmonary bypass.

New trends of root canal disinfection and treatment strategies for infected root canal based upon evidence-based dentistry

  • Cho, Yong-Bum
    • Proceedings of the KACD Conference
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    • pp.608-608
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    • 2003
  • The main objectives of root canal therapy are cleaning and shaping and then obturating the root canal system in 3 dimensions to prevent reinfection. Many instrumentation techniques and devices, supported by an irrigation system capable of removing pulp tissue remnants and dentin debris, have been proposed to shape root canals. But current regimens in chemomechanical debridement using instrumentation and irrigation with NaOCl are not predictably effective in root canal disinfection. These findings are not surprising because the root canal system is complex and contains numerous ramifications and anatomical irregularities. The microorganisms in root canals not only invade the anatomic irregularities of the root canal system but also are present in the dentinal tubules. Therefore further disinfection with an effective antimicrobial agent may be necessary and it well1mown that use of intracanal medication will lower bacterial count in infected root canals. Calcium hydroxide has a long history of use in endodontics, and more attention has been given to the use of calcium hydroxide as intracanal dressing for the treatment of infected pulp. However, when treatment is completed in one visit, no intracanal medications other than intracanal irrigants are used. Recently, a mixture of a tetracycline isomer, an acid, and a detergent(MTAD), has been introduced as a final rinse for disinfuction of the root canal system. It has been shown that MTAD is able to remove the smear layer with minimal erosive changes on the surface of dentin, and is effective against Enterococcus faecalis, a microorganism resistant to the action of other antimicrobial medications. In another study, the ability of MTAD was investigated to disinfect contaminated root canals with whole saliva and compared its efficacy to that of NaOCl Based on the results, it seems that MTAD is significantly more effective than 5.25% NaOCl in eradicating bacteria from infected root canals. In the cytotoxicity evaluation, MTAD is less cytotoxic than engenol, 3% $H20_2,\;Ca(OH)_2$ paste, 5.25% NaGCl, Peridex, and EDTA and more cytotoxic than 2.63%,1.31% and 0.66% NaOCl. Is it promising or transient?

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Chronologic chrnge of serum IgG antibody response in chickens reinfected with Cryptosporidium baileyi (닭와포자충 재감염닭의 혈청1gG 항체가 추이)

  • Lee, Jae-Gu;Kim, Hyeon-Cheol;Park, Bae-Geun
    • The Korean Journal of Parasitology
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    • v.34 no.4
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    • pp.255-258
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    • 1996
  • Eight 2-day-old SPF Chickens were each inoculated Orally With 3 Sing1e dose Of 5 × 105 oocysts of Cryptosporinium boilevi. and immunoglobulin G (IgG) antibody responses were chronologically measured by indirect immunofluorescent antibody (IFA) assay. Anti-C. bcileyi IgG antibody levels remained high (1 : 106.67 to 1:512.00) for at least 4 months with 330 days of a detectable period. Ten days after the negative conversion, each chicken was re-challenged with 1 × 107 oocysts of the same species. Subsequent infection in 340-day-old individuals caused sudden elevated IgG antibody levels and the titer peaked on day 28 postchallenge inoculation (PCI), at 1:1.024 with a 65 days of detection period. Chickens in primary infection showed oocyst shedding profiles. but did not exhibit any oocyst shedding before or after experimental reinfection.

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Pathogenicity of the fish nodavirus causing viral nervous necrosis of sevenband grouper, Epinephelus septemfasciatus (능성어, Epinephelus septemfasciatus의 바이러스성 신경괴사증 바이러스의 병원성 연구)

  • Sohn, Sang-Gyu;Chun, Seh-Kyu
    • Journal of fish pathology
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    • v.12 no.2
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    • pp.107-113
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    • 1999
  • The pathogenicity of the fish nodavirus causing viral nervous necrosis (VNN) of sevenband grouper, Epinephelus septemfasciatus was examined in sevenband grouper and other marine fish by intramuscular injection. Sevenband groupers of 27~104 g in body weight were highly susceptible to the fish nodavirus, but yellowtail (537 g in body weight), red seabream (207 g), rock bream (43 g), flounder (41 g), tiger puffer (27 g) and rockfish (94 g) of the sizes used to this experiment were not. The pathogenicity of the viral agent to the sevenband grouper was high without regard to fish sizes at rearing water temperature over $20^{\circ}C$, but not at $15^{\circ}C$. Therefore, susceptibility of sevenband grouper to the viral agent causing VNN was thought to be water temperature-dependent rather than fish size (age-dependent). Compared to the infectivity of the viral agent to sevenband grouper with artificial infection methods, fish were successfully affected by intramuscular, intraperitoneal, oral, dipping and cohabitation administrations although there were slight differences in mortalities among infection methods. And survival sevenband grouper after infection with the fish nodavirus was resistant to the reinfection for a long time.

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Rapid Typing of Clinical Strains of Mycobacterium tuberculosis by IS6110-based Outward PCR

  • Kim, Yeun;Lee, Uen-Ho;Park, Young-Kil;Bai, Gill-Han;Cho, Sang-Nae;Lee, Hye-Young
    • Biomedical Science Letters
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    • v.10 no.2
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    • pp.163-169
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    • 2004
  • Worldwide, tuberculosis remains one of the leading infectious diseases, accounting for nearly 3 million deaths and more than 8 million new cases annually. DNA typing of Mycobacterium tuberculosis is important for the control of tuberculosis, since it can be used to track transmission route of tuberculosis, source of internal laboratory contaminations, and to answer questions on the nature of tuberculosis infections such as reactivation or exogenous reinfection of disease. At present, IS6110-based RFLP is the choice of method for typing large numbers of clinical isolates of M. tuberculosis, since it has the highest resolution power. However, RFLP requires long time, high cost and qualified experts, so only reference level laboratories can use the RFLP technique. In order to have an optional molecular typing method suitable for the clinical settings, this study evaluated the use of one of PCR-based typing methods, IS6110-based outward PCR for typing clinical isolates of M. tuberculosis. In brief, the results from this study showed that IS6110-based RFLP is useful to discriminate diverse clinical isolates of M. tuberculosis as well as to identify clinical isolates that belong to the same family or cluster groups that have been previously classified by RFLP analysis. In addition, the banding profiles resulted from IS6110-based outward PCR seemed to represent genomic characteristics of M. tuberculosis, since strains belong to the K-family generated unique band that is not present in any other strains but present only in the genome of K-family strains. The IS6110-based outward PCR was also shown to be useful with DNAs isolated directly from liquid cultures indicating this method can be suitable for typing M. tuberculosis in clinical settings.

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Helicobacter pylori in the Oral Cavity (구강 내 Helicobacter pylori)

  • Ahn, Jong-Mo
    • Journal of Oral Medicine and Pain
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    • v.37 no.2
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    • pp.75-79
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    • 2012
  • Helicobacter pylori(H. pylori) associated with gastritis and gastric cancer is mainly detected dental plaque and saliva in the oral cavity. Most infection is probably acquired in childhood, but the route of transmission is not clear. The oral cavity has been indicated as secondary reservoir of H. pylori, and may therefore be argued in the route of transmission and reinfection of the stomach which follows treatment of H. pylori infection. So this review aimed to discuss about H. pylori in the oral cavity. H. pylori in stomach can appear in the oral cavity by gastroesophageal reflex or vomiting, but infection of stomach and oral cavity is different. Diagnostic methods are serological method, urea breath test, PCR method, urease test, histologic method and so on. Nested PCR recommend for detection of H. pylori in saliva and dental plaque. H. pylori infection in the oral cavity appear variously and is no relation with dental diseases. The antimicrobial mouthrinse recommend in patients with periodontal diseases because of high detection rate fo H. pylori. Thus H. pylori may be considered as the normal oral microflora.