Caries prediction using the caries activity test with a sulfisomidine mixture: a 3-year follow-up study / 대한구강보건학회지

OBJECTIVES: The purpose of this study was to evaluate the prediction validity of the caries activity test with a sulfisomidine mixture (SAHS test). METHODS: This longitudinal follow-up study was conducted for 3 years. The subjects were 155 elementary schoolchildren. Oral examination was performed by examining each tooth surface of the subjects. The number of teeth with new caries lesions was calculated by comparing between the baseline data of the initial oral examination and the results of the second oral examination performed after 3 years. The Dentocult SM test was used as the reference in the analysis of the caries prediction validity of the SAHS test. The items of the validity test for carries prediction were as follows: sensitivity, specificity, predictive value, and likelihood ratio. RESULTS: The correlation between new caries lesions and the SAHS test scores was greater than that between new caries lesions and the Dentocult SM test scores. The receiver-operating analysis revealed that the area under the curve of the SAHS test was higher than that of the Dentocult SM test. The caries prediction validity of the SAHS test (grade 12) was as follows: sensitivity, 0.71-0.70; specificity, 0.60-0.58; positive predictive value, 0.79-0.78; negative predictive value, 0.49 (screening criterion 5). The SAHS test scores were similar to or higher than the scores in the items of the Dentocult SM test. CONCLUSIONS: The SAHS test is considered useful for clinical applications.

Epidemiologic analysis of Shigella sonnei Isolates by using Antimicrobial Resistance Gene Probes

Thirty-four Shigella sonnei isolates from 6 outbreaks and sporadic cases from May 1999 until January 2000 in Daegu and 9 regions of Gyeongsangbuk-Do were epidemiologically analyzed by plasmid profiling, pulsed-field gel electrophoresis (PFGE), and hybridization with 2 antimicrobial resistance gene probes, tetA and dfrA1. In outbreak cases, resistance pattern in all of the strains was identical: they were resistant to tetracycline (Tc), streptomycin (Sm), sulfisomidine (Su), trimethoprim (Tp), and nalidixic acid (Na). In sporadic cases, Tc, Sm, Su, Na, ampicillin (Ap), and kanamycin (Km) pattern and TcSmSuTpApNa pattern were additionally observed. Isolates from the same outbreak showed identical plasmid profile and PFGE pattern. Most of different outbreak strains and sporadic strains showed different plasmid profiles, and identical or different PFGE patterns, while all of the isolates shared common tetA gene on a non-conjugative 18.3 kbp R plasmid carrying resistance to tetracycline, streptomycin, and sulfisomidine, and dfrA1 gene on the chromosome. Non-conjugative R plasmids derived from all of the isolates were confirmed to be identical by the Southern hybridization analysis of restriction endonuclease treated or non-treated plasmid profiles using the tetA probe. The same strains also reacted with dfrA1 probe at the same-sized DNA fragment (60 kbp) on pulsed-field gel electrophoresis of total genomic DNA. Our findings suggested that epidemic strains of Shigella sonnei prevalent in the Daegu and Gyeongsangbuk-Do area during the test period should have originated from an identical or closely related strain source although most of strains did not show the same plasmid profile and PFGE pattern.

Antimicrobial resistance and molecular epidemiologic characteristics of Stenotrophomonas maltophilia isolated from clinical specimens

Sixty-eight clinical isolates of Stenotrophomonas maltophilia from inpatients of 2 university hospitals in Taegu were epidemiologically analyzed by using the minimum inhibitory concentrations of 25 antimicrobial drugs, biochemical reaction, pulsed-field gel elctropgoresis (PFGE), and PCR with enterobacterial repetitive intergenic consensus sequences as primer (ERIC-PCR). 1. All the strains were susceptible to minocycline. More than 57% were susceptible to sulfisomidine (Su), ciprofloxacin (Ci), Ofloploxacin (Of), nalidixic acid (Na), and chloramphenicol (Cm), and 19apprx35% to ceftazidime (Cd), trimethoprim (Tp), Ticacillin-clavulanic acid, and cefoperazone-sulbactam. Most isolates were resistant to beta-lactam antibiotics such as ampicillin (Ap), carbenicillin (Cb), cefotaxim (Ct), cefoxitin (Cx), and aminoglycosides including gentamicin (Gm), tobramycin (Tb), amikacin (Ak). 2. All the isolates were multiply resistant of 5 to 17 drugs and showed 40 different resistance pattern types. 3. All the strains showed very similar biochemical reactions except beta-galactosidase and nitrate reduction test. Fourteen strains selected randomly were classified 10 different pattern type by PFGE and ERIC-PCR. These two methods showed identical result. Four strains isolated from wound in 1994 showed similar MIC pattern and identical API 20NE profile, PFGE, and ERIC-PCR pattern indicating episodes of cross-infection among patients. These results indicate that PFGE or ERIC-PCR profile has comparable discriminatory power for epidemiological typing of S. maltophilia.

Molecular Epidemiologic Analysis of Nosocomial Escherichia coli Isolates

One hundred and eighteen strains of Escherichia coli isolated from clinical specimens were epidemiologically analyzed for antimicrobial resistance, EcoRI restriction endonuclease analysis, southern hybridization with TEM and SHV probe of conjugative R plasmids. 1. Sixty-two to 73% of E. coli isolates were resistant to ampicillin, carbenicillin, sulfisomidine, and tetracycline, and 20-27% to kanamycin, gentamicin, tobramycin, and nalidixic acid. However more than 93% were susceptible to cephalosporins and all strains were highly susceptible to cefotetan, imipenem, aztreonam, and amikacin. 2. Twelve strains were susceptible to all drugs tested and the multiple resistant strains showed 65 resistance pattern types. 3. Thirty-six resistant strains(34%) transferred R plasmids to E. coli RG488 or RG176 by mixed culture. Fifty-six plasmids with 31 different resistant phenotype were obtained from them. 4. Some of 15 plasmids derived from 10 strains showed identical or similar EcoRI restriction endonuclease digestion patterns, hybridized fragment patterns with TEM probe by southern hybridization, and resistance levels of j3-lactams and aminoglycosides. These results indicate that the epidemic strains or plasmids were present in this hospital and molecular genetic analysis of R plasmids can be used to discriminate clinical isolates of multi- resistant E. coli.

Antimicrobial drug resistance and molecular charaterization of R-plasmid of escherichia coli isolated from urine / 대한비뇨기과학회지

Ninety nine strains of Escherichia coli isolated from clinical urine specimens in Taegu area were tested for the antimicrobial susceptibility to 20 drugs and studies for molecular and genetic characterization of R-plasmid. All strains were susceptible to amikacin (Ak), moxalactam(Mx), norfloxacin(Nf), ciprofloxacin(Cf) and ofloxacin(Of). One-6.1% of the strains were resistant to tobramycin(To). nalidixic acid(Na), enoxacin(Ex), pefloxacin(Pf) and rifampin(Rf), 17.2-31.3% to gentamicin(Gm), cephalothin(Ct) and cephamandole(Cfm), and 59.6-84.4% to kanamycin (Km), streptomycin(Sm), a.mpicillin(Ap), chloramphenicol(Cm), tetracycline(Tc), sulfisomidine (Su) and trimethoprime(Tp). MIC90 of Ak, Mx, Ex, Nf, Cf, Of and Pf were below the aritimicrobial concentration tested. In multiple drug resistance patterns, resistance to 7 drugs (CmTcSmSuAp TpKm) were most frequently encountered. Except Na and Rf in 66.4 % of resistant strains, most or drug resistance were co-transferred to recipient E.coli RG488 or RG176, indicating that multiple drug resistance was R-plasmid mediated phenomenon. Plasmid profiles for molecular characterization of R-plasmids from B. coli strains were studied through the methods of alkaline SDS lysis and agarose gel electrophoresis. R-plasmids were 40.9-122.3 mega dalton in molecular size. Pst I restriction enzyme digestion patterns of R-plasmid DNAs were examined. R-plasmids with different molecular weights and phenotype markers showed different restriction patterns. pDE9l58 and pDE 9055, which have same molecular weight and phenotype marker except Cfm, showed identical restriction pattern.

Distribution of silfusomidine in tissues of poultry.

The biological half life, blood level and tissue dispersion of sulfisomidine in poultry have been studied. The biological half life was observed to be 40 minuts. Following single dose (275 mg/kg) oral administration, the peak blood level of 13.92 mg% was found at 2 hr and the liver and small intestine showed highest drug residue at the end of 24 hr.