Comparison of PCR, Culture and Serologic Tests for Diagnosis of Mycoplasma pneumoniae Infection / 소아알레르기및호흡기학회지

PURPOSE: For diagnosis of Mycoplasma pneumoniae infection, serological diagnosis, which is simple and rapid method, is uncertain to determine the reliable single serum titers. We compared serologic test, culture and polymerase chain reaction (PCR), and evaluated the reliable single titers of the specific serum antibody determination method for diagnosis of M. pneumoniae infection. METHODS: We included 73 pneumonic children between 3-11 years who were admitted to the pediatric department of St. Benedict hospital between November 2002 and July 2003. We used indirect particle agglutination test (Serodia-Myco II; Fujirebio, Tokyo, Japan) and serum specimens were obtained on admission and after 5-10 days. Fourfold rise of Mycoplasma antibody titers was considered as M. pneumoniae infection. We collected the throat swabs from all of the participants for culture and PCR. RESULTS: Of 73 patients, 41 patients met the diagnostic criteria by serologic test. PCR for M. pneumoniae was positive for 33 patients, sensitivity 80.5%, specificity 90.6%. M. pneumoniae was cultured from 24 patients, sensitivity 59%, specificity 100%. When cut-off was set at a titer of > or =1: 160, the sensitivity and specificity of PCR were significantly higher (61 % vs 68%) by receiver operation characteristic curve. (P=0.035) There was no correlation between culture method and Mycoplasma Ab titer. CONCLUSION: PCR is a highly sensitive and specific diagnostic method and enough to allow for early diagnosis in the acute phase. The single Mycoplasma Ab titer > or =1: 160 in child with respiratory symptoms is considered as M. pneumoniae infection and would be more sensitive, when combined with PCR.

Analysis of Clarithromycin Resistance of Helicobacter pylori Isolated in Korea

Forty-four strains of Helicobacter pylori were isolated from Kosin Medical Center were tested of resistance to antimicrobial agents, and the mechanism of resistance to clarithromycin was investigated. We determined the MICs of amoxicillin, amoxicillin/clavulanic acid, clarithromycin, and metronidazole by agar and broth dilution method. To detect the mutations of 23S rRNA which is associated with clarithromycin resistance, a 3'-mismatched polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis with restriction enzymes BbsI and BsaI were performed. The nucleotide sequence of 23S rRNA was determined. All H. pylori strains appeared to be susceptible to amoxicillin/clavulinic acid, but 2.3% of strains (1 strain) are resistant to amoxicillin, 13.6% (6 strains) to clarithromycin, and 15.9% (7 strains) to metronidazole. No PCR products was observed by the 3'-mismatched PCR. A 291 bp of PCR product was not digested by BbsI, but was digested by BsaI, which was a characteristic of the A2143G point mutation in the 23S rRNA gene. The nucleotide sequencing analysis revealed that all resistant strains had A2143G, T2182C, and T2244C mutations in 23S rRNA gene.

Detection and Isolation of Genital Mycoplasmas from Public Toilet Bowls

Genital mycoplasmas are sexually transmitted. There are considerable public concern that causative agents of sexually transmitted diseases might be transmitted nonsexually through public restrooms. In the present study, Mycoplasma hominis, Ureaplasma urealyticum and M. penetrans among genital mycoplasmas were identified in 100 public restroom toilet bowls (50 men's and 50 women's public restrooms, each). Mycoplasmas were genotypically identified by two methods; (1) PCR of primary selective culture and (2) direct PCR of original specimens before primary selective culture. From 50 men's public restrooms, M. hominis, U. urealyticum and M. penetrans were identified from PCR of primary selective cultures in 6%, 4% and 0% of the specimens, respectively and M. hominis and U. urealyticum was codetected in 2% of those. And M. hominis, U. urealyticum and M. penetrans were identified by direct PCR in 20%, 16% and 0% of the original specimens, respectively and co-detection rate of M. hominis and U. urealyticum was 4% in those. From 50 women's public restrooms, 38% was positive for M. hominis, 14% for U. urealyticum, 0% for M. penetrans and 10% for both U. urealyticum and M. penetrans by PCR of primary selective culture. And 50% was positive for M. hominis, 46% for U. urealyticum and 0% for M. penetrans and 34% for both M. hominis and U. urealyticum by direct PCR of the original specimens. These results indicate that the genital mycoplasmas can survive for considerable duration in toilet bowels, and might be transmitted by through public restrooms.