Molecular Typing and Resistance Profiles of Vancomycin-Intermediate Staphylococcus aureus in Korea: Results from a National Surveillance Study, 2007-2013 / 대한임상미생물학회지

BACKGROUND: To investigate the national molecular epidemiology and resistance profiles of vancomycin-intermediate Staphylococcus aureus (VISA), we analyzed the characteristics of methicillin-resistant Staphylococcus aureus (MRSA) collected from clinical samples at tertiary or general hospitals participating in a nationwide surveillance program for VISA and vancomycin-resistant Staphylococcus aureus (VRSA) in Korea during an 12-week period in each year from 2007 to 2013. METHODS: VISA was defined by agar dilution, broth dilution and E-test methods with vancomycin minimum inhibitory concentrations of >2 μg/mL. All VISA isolates were characterized by multilocus sequence typing, staphylococcal cassette chromosome mec typing, spa typing, accessory gene regulator typing, Diversilab analysis, and antibiogram analysis. RESULTS: Of 109,345 MRSA isolates, 87,354 were screened and 426 isolates were identified as positive on brain heart infusion agar containing 4 μg/mL vancomycin (BHI-V4). Of 426 isolates, 76 isolates were identified as VISA. No VRSA isolates were detected among the isolates. Overall, a total of 6 genotypes were identified among VISA strains and the predominant clones were ST5-II-t2460, ST72-IV-t324, and ST239-III-t037 (44.7%, 15.8%, and 10.5%, respectively). Of note, ST72-IV-t324 clones are known to be a typical community-associated MRSA. ST239-III-t037 strains were more resistant to trimethoprim-sulfamethoxazole than any other type of strain. ST72-IV-t324 strains were susceptible to all of the antimicrobial agents tested except erythromycin and daptomycin. All of the VISA isolates were susceptible to linezolid and quinupristin-dalfopristin. CONCLUSION: Although VRSA is still rare, continuous monitoring of VRSA occurrence is needed, as well as VISA prevalence, epidemic clonal shift, and antimicrobial resistance.

Molecular and Epidemiological Characterization of Carbapenem-Resistant Acinetobacter baumannii in Non-Tertiary Korean Hospitals

PURPOSE: The increasing prevalence and global spread of carbapenem-resistant Acinetobacter baumannii (A. baumannii) has become a serious problem. The aim of this study was to investigate molecular and epidemiological characteristics of carbapenem-resistant A. baumannii isolates collected from Korean non-tertiary hospitals. MATERIALS AND METHODS: Thirty six non-duplicated carbapenem-resistant A. baumannii isolates were collected from 17 non-tertiary hospitals in Korea between 2004 and 2006. Isolates were typed by multilocus sequence typing and repetitive-sequence-based PCR (rep-PCR). Detection of genes encoding OXA carbapenemase and their relationship with ISAba1 was performed by PCR. RESULTS: Two clones were prevalent among 36 isolates: ST69 (17 isolates, 47.2%) and ST92 (19 isolates, 52.8%). Rep-PCR patterns were diverse and revealed that all isolates were clustered into eight band patterns. The ISAba1-activated blaOXA-23-like and ISAba1-activated blaOXA-51-like genes were prevalent among the carbapenem-resistant A. baumannii isolates. CONCLUSION: The class D beta-lactamase genes of A. baumannii were distributed nationwide in non-tertiary Korean hospitals.

Sentinel Surveillance and Molecular Epidemiology of Multidrug Resistance Bacteria / 대한임상미생물학회지

The global emergence and spread of multidrug resistant bacterial infections in communities and hospitals has become an important issue in public health. The resistance rate of gram-positive cocci to vancomycin and the resistance rate of several gram-negative bacilli against cefotaxime and carbapenem have been continuously increasing. Surveillance of antimicrobial resistance is essential for providing information on the magnitude of and trend in multidrug resistance. Therefore, beginning 2011, more robust and effective management is to be legally required for six multidrug-resistant bacteria that have been linked to healthcare-related infections: vancomycin-resistant Staphylococcus aureus (VRSA), vancomycin-resistant enterococci (VRE), methicillin-resistant S. aureus (MRSA), multidrug-resistant Pseudomonas aeruginosa (MRPA), multidrug-resistant Acinetobacter baumannii (MRAB), and carbapenem-resistant Enterobactericeae (CRE). We have also performed laboratory-based sentinel surveillance for VRSA/VISA since 2002 and carbapenemase-producing Enterobacteriaceae since November, 2010. This article reviews the national surveillance programs, and molecular epidemiology of multidrug-resistant bacteria.

Distribution of Genes Encoding Aminoglycoside Modifying Enzymes and Type Staphylococcal Chromosomal Cassette mec in Methicillin-resistant Staphylococcus aureus from Non-tertiary Hospitals

BACKGROUND: Many genes encoding aminoglycoside modifying enzymes (AMEs) on transposon or plasmid were transferred from one strain to another strain and inserted into a staphylococcal chromosomal cassette mec (SCCmec). There are very diverse subtypes in SCCmec type to the insertion of resistant genes. Therefore, we researched the resistance rates of antibiotics and distribution of AME genes according to SCCmec type in MRSA strains. MATERIALS AND METHODS: We isolated 640 Staphylococcus aureus from non-tertiary hospitals in 2004, detected mecA, aac(6')-aph(2"), aph(3')-IIIa, and ant(4')-Ia using the multiplex PCR method, tested antibacterial susceptibility disk diffusion and minimal inhibitory concentration, and determined SCCmec type. RESULTS: Of 640 S. aureus isolates, MRSA rate was 39.7% and all MRSA isolates carried mecA gene. Among 214 MRSA selected, aminoglycoside-resistant rates were 98.1% in kanamycin and tobramycin, 68.7% in gentamicin, 30.8% in amikacin, and 2.8% in netilmicin. The detection rates for aac(6')-aph(2"), aph(3')-IIIa, and ant(4')-Ia were 77.1%, 13.1%, and 53.3%, respectively. Also, SCCmec type was 50.9% in SCCmec type II, 16.4% in type III, and 32.7% in type IV. The genes encoding AMEs were distributed aac(6')-aph(2") (49.5%) and aac(6')-aph(2")/ant(4')-Ia (36.7%) in SCCmec type II, aph(3')-IIIa/aac(6')-aph(2") (60%) and aac(6')-aph(2") (31.4%) in type III, and aac(6')-aph(2")/ant(4')-Ia (41.4%) and ant(4')-Ia (50%) in type IV. CONCLUSION: 39.7% of S. aureus isolated from non-tertiary hospitals was resistant to methicillin. More than 90% of MRSA isolates were detected aac(6')-aph(2") in SCCmec type II and III, and ant(4')-Ia in type IV. With these results, the genes encoding AMEs may be closed related to SCCmec type.

Distribution of Genes Encoding Aminoglycoside Modifying Enzymes and Type Staphylococcal Chromosomal Cassette mec in Methicillin-resistant Staphylococcus aureus from Non-tertiary Hospitals

BACKGROUND: Many genes encoding aminoglycoside modifying enzymes (AMEs) on transposon or plasmid were transferred from one strain to another strain and inserted into a staphylococcal chromosomal cassette mec (SCCmec). There are very diverse subtypes in SCCmec type to the insertion of resistant genes. Therefore, we researched the resistance rates of antibiotics and distribution of AME genes according to SCCmec type in MRSA strains. MATERIALS AND METHODS: We isolated 640 Staphylococcus aureus from non-tertiary hospitals in 2004, detected mecA, aac(6')-aph(2"), aph(3')-IIIa, and ant(4')-Ia using the multiplex PCR method, tested antibacterial susceptibility disk diffusion and minimal inhibitory concentration, and determined SCCmec type. RESULTS: Of 640 S. aureus isolates, MRSA rate was 39.7% and all MRSA isolates carried mecA gene. Among 214 MRSA selected, aminoglycoside-resistant rates were 98.1% in kanamycin and tobramycin, 68.7% in gentamicin, 30.8% in amikacin, and 2.8% in netilmicin. The detection rates for aac(6')-aph(2"), aph(3')-IIIa, and ant(4')-Ia were 77.1%, 13.1%, and 53.3%, respectively. Also, SCCmec type was 50.9% in SCCmec type II, 16.4% in type III, and 32.7% in type IV. The genes encoding AMEs were distributed aac(6')-aph(2") (49.5%) and aac(6')-aph(2")/ant(4')-Ia (36.7%) in SCCmec type II, aph(3')-IIIa/aac(6')-aph(2") (60%) and aac(6')-aph(2") (31.4%) in type III, and aac(6')-aph(2")/ant(4')-Ia (41.4%) and ant(4')-Ia (50%) in type IV. CONCLUSION: 39.7% of S. aureus isolated from non-tertiary hospitals was resistant to methicillin. More than 90% of MRSA isolates were detected aac(6')-aph(2") in SCCmec type II and III, and ant(4')-Ia in type IV. With these results, the genes encoding AMEs may be closed related to SCCmec type.

Antimicrobial Resistance among Clinical Isolates of Pseudomonas aeruginosa from Non-tertiary Care Hospitals in Korea, 2002-2004

BACKGROUND: Increasing numbers of resistant and multidrug resistant (MDR) isolates of Pseudomonas aeruginosa have become a worldwide problem. This report provides the trend of antimicrobial resistance, the proportions of MDR and metallo-beta-lactamase-producing isolates among clinical isolates of P. aeruginosa in Korea. MATERIALS AND METHODS: Clinical isolates of P. aeruginosa were collected from two representative reference laboratories during 2002-2004. Clinical information regarding specimens and type of hospital for isolates was investigated. Antimicrobial susceptibility against 11 antibiotics was tested by disk diffusion according to NCCLS criteria. MDR was assessed as resistance to > or =3 of the core drugs (ceftazidime, ciprofloxacin, gentamicin, imipenem and piperacillin). PCR assays and sequencing for detection of blaVIM-2 and blaIMP-1 gene were carried out. RESULTS: Of 1,748 P. aeruginosa isolates, 179 isolates were collected from primary care hospitals and 1,569 isolates were recovered from outpatients and inpatients in secondary care hospitals. From 2002 to 2004, rates of resistance to ceftazidime and imipenem increased from 10% to 12.3% and from 14.8% to 15.9%, respectively. Rates of resistance to amikacin (from 26.2% to 31.0%) and ciprofloxacin (from 35.6% to 46.2%) increased annually. In the period 2002-2004, decreasing of susceptibility to meropenem (from 83.4% to 76.8%) was observed, but meropenem was the most potent agent against P. aeruginosa isolates studied. During the 3-year period, MDR P. aeruginosa accounted for 26.4-33.5% of clinical isolates and the most common MDR phenotype was concurrent resistance to piperacillin, gentamicin and ciprofloxacin. The prevalence of VIM-2-producing isolates obviously increased from 1.7% in 2002 to 6.3% in 2004. CONCLUSIONS: These results suggested that MDR P. aeruginosa was already prevalent in one third of clinical isolates and VIM-2-producing P. aeruginosa isolates disseminated in non-tertiary care hospitals in Korea.

Prevalence and Genetic Relatedness of Vancomycin-resistant Enterococci Isolated from Livestock and Humans after Ban of Avoparcin in Korea

BACKGROUND: Avoparcin, cross-resistance with vancomycin, was added as feed-additive since 1970s and was prohibited in 1997 in Korea. After avoparcin was banned we examined prevalence and genetic relatedness of VRE in enterococci isolated from livestock and humans. MATERIALS AND METHODS: Using enrichment broth and 6 microgram/mL vancomycin-containing enterococcosel selective agar, vancomycin-resistant enterococci (VRE) were isolated from fecal sample of 255 pigs of 8 farms, 431 chickens of 9 farms, and 328 humans (Food industry employee and Institution cafeteria employee) of 5 public health centers, and 100 raw chicken meats from April to June 2003. Antimicrobial susceptibility was examined by disk diffusion and minimum inhibitory concentrations (MICs), and E-test. Species identification and genotyping were done by multiplex PCR method. Pulsed-field gel electrophoresis (PFGE) of vanA-type VRE isolates was performed by CHEF-Mapper system. RESULTS: 19 isolates from 255 pigs, 122 isolates from 431 chickens, 19 isolates from 100 raw chicken meat, and 7 isolates from 328 humans were resistant to vancomycin. Of the 167 VRE isolates, vanA gene was detected in 141 isolates; 1 isolate (0.4%) in pigs, 121 isolates (28.1%) in chickens, 18 isolates (18.0%) in raw chicken meat, and 1 isolate (0.3%) in humans. Resistant rates of streptomycin, tetracycline, and erythromycin were over 60% in vanA-type E. faecium isolated from poultry. PFGE analysis resulted in two major patterns, F and P types. Also PFGE pattern of 1 VRE from human was identical to that of 1 VRE from poultry. CONCLUSION: Despite the high prevalence of vanA-type VRE in poultry farms, VRE isolation rate in human was relatively low. This result suggests that the possibility of VRE transmission from poultry to human is low but that possibility may be not ruled out. In PFGE analysis showing 51.5% identical in 2 PFGE patterns, the dissemination of VRE isolates in poultry may be transmitted vertically and horizontally.

Antimicrobial Resistance among Clinical Isolates of Pseudomonas aeruginosa from Non-tertiary Care Hospitals in Korea, 2002-2004

BACKGROUND: Increasing numbers of resistant and multidrug resistant (MDR) isolates of Pseudomonas aeruginosa have become a worldwide problem. This report provides the trend of antimicrobial resistance, the proportions of MDR and metallo-beta-lactamase-producing isolates among clinical isolates of P. aeruginosa in Korea. MATERIALS AND METHODS: Clinical isolates of P. aeruginosa were collected from two representative reference laboratories during 2002-2004. Clinical information regarding specimens and type of hospital for isolates was investigated. Antimicrobial susceptibility against 11 antibiotics was tested by disk diffusion according to NCCLS criteria. MDR was assessed as resistance to > or =3 of the core drugs (ceftazidime, ciprofloxacin, gentamicin, imipenem and piperacillin). PCR assays and sequencing for detection of blaVIM-2 and blaIMP-1 gene were carried out. RESULTS: Of 1,748 P. aeruginosa isolates, 179 isolates were collected from primary care hospitals and 1,569 isolates were recovered from outpatients and inpatients in secondary care hospitals. From 2002 to 2004, rates of resistance to ceftazidime and imipenem increased from 10% to 12.3% and from 14.8% to 15.9%, respectively. Rates of resistance to amikacin (from 26.2% to 31.0%) and ciprofloxacin (from 35.6% to 46.2%) increased annually. In the period 2002-2004, decreasing of susceptibility to meropenem (from 83.4% to 76.8%) was observed, but meropenem was the most potent agent against P. aeruginosa isolates studied. During the 3-year period, MDR P. aeruginosa accounted for 26.4-33.5% of clinical isolates and the most common MDR phenotype was concurrent resistance to piperacillin, gentamicin and ciprofloxacin. The prevalence of VIM-2-producing isolates obviously increased from 1.7% in 2002 to 6.3% in 2004. CONCLUSIONS: These results suggested that MDR P. aeruginosa was already prevalent in one third of clinical isolates and VIM-2-producing P. aeruginosa isolates disseminated in non-tertiary care hospitals in Korea.

Prevalence and Genetic Relatedness of Vancomycin-resistant Enterococci Isolated from Livestock and Humans after Ban of Avoparcin in Korea

BACKGROUND: Avoparcin, cross-resistance with vancomycin, was added as feed-additive since 1970s and was prohibited in 1997 in Korea. After avoparcin was banned we examined prevalence and genetic relatedness of VRE in enterococci isolated from livestock and humans. MATERIALS AND METHODS: Using enrichment broth and 6 microgram/mL vancomycin-containing enterococcosel selective agar, vancomycin-resistant enterococci (VRE) were isolated from fecal sample of 255 pigs of 8 farms, 431 chickens of 9 farms, and 328 humans (Food industry employee and Institution cafeteria employee) of 5 public health centers, and 100 raw chicken meats from April to June 2003. Antimicrobial susceptibility was examined by disk diffusion and minimum inhibitory concentrations (MICs), and E-test. Species identification and genotyping were done by multiplex PCR method. Pulsed-field gel electrophoresis (PFGE) of vanA-type VRE isolates was performed by CHEF-Mapper system. RESULTS: 19 isolates from 255 pigs, 122 isolates from 431 chickens, 19 isolates from 100 raw chicken meat, and 7 isolates from 328 humans were resistant to vancomycin. Of the 167 VRE isolates, vanA gene was detected in 141 isolates; 1 isolate (0.4%) in pigs, 121 isolates (28.1%) in chickens, 18 isolates (18.0%) in raw chicken meat, and 1 isolate (0.3%) in humans. Resistant rates of streptomycin, tetracycline, and erythromycin were over 60% in vanA-type E. faecium isolated from poultry. PFGE analysis resulted in two major patterns, F and P types. Also PFGE pattern of 1 VRE from human was identical to that of 1 VRE from poultry. CONCLUSION: Despite the high prevalence of vanA-type VRE in poultry farms, VRE isolation rate in human was relatively low. This result suggests that the possibility of VRE transmission from poultry to human is low but that possibility may be not ruled out. In PFGE analysis showing 51.5% identical in 2 PFGE patterns, the dissemination of VRE isolates in poultry may be transmitted vertically and horizontally.

Antimicrobial Resistance of Clinical Isolates of Acinetobacter spp. Collected from Non-Tertiary Hospitals and Detection of a Metallo-beta-Lactamase-Producing Strain

BACKGROUND: The aim of this study was to investigate the antimicrobial resistance of clinical isolates of Acinetobacter spp. collected from non-tertiary hospitals and to characterize the phenotype and the genotype of imipenem-non-susceptible isolates. MATERIALS AND METHODS: Clinical isolates of Acinetobacter spp. were identified using recA-restriction fragment length polymorphism (RFLP) analysis with Tsp5091. Susceptibility to antimicrobial agents was determined using disk diffusion test and agar dilution test according to the criteria of the National Committee for Clinical Laboratory Standards. PCR and sequence analyses were used to detect the blaIMP-1 and blaVIM-2 genes, and to determine the content and order of the resistance genes inserted in integron. RESULTS: Of 71 Acinetobacter spp. isolates collected from non-tertiary hospitals during 2002 and 2003, 60 isolates were A. baumannii, and 2, 4, and 5 isolates were Acinetobacter genomic species 3, 13TU, and A. lwoffii, respectively. The resistance rate of Acinetobacter spp. isolates to beta-lactams, aminoglycosides, and fluoroquinolones was high except for imipenem and meropenem. The presence of blaVIM-2 gene was found in one isolate, Acinetobacter genomic species 13TU, for which the MIC of imipenem was 8 mg/L; the blaVIM-2 gene of this strain was located on 3 kb class 1 integron with aacA7 and aadA1 genes. CONCLUSIONS: Among the tested agents, imipenem and meropenem retained greatest activity against Acinetobacter spp. isolates collected from non-tertiary hospitals. This is the first report of VIM-2-producing Acinetobacter genomic species 13TU strains with class 1 integron containing blaVIM-2 gene.

Antimicrobial Resistance of Clinical Isolates of Acinetobacter spp. Collected from Non-Tertiary Hospitals and Detection of a Metallo-beta-Lactamase-Producing Strain

BACKGROUND: The aim of this study was to investigate the antimicrobial resistance of clinical isolates of Acinetobacter spp. collected from non-tertiary hospitals and to characterize the phenotype and the genotype of imipenem-non-susceptible isolates. MATERIALS AND METHODS: Clinical isolates of Acinetobacter spp. were identified using recA-restriction fragment length polymorphism (RFLP) analysis with Tsp5091. Susceptibility to antimicrobial agents was determined using disk diffusion test and agar dilution test according to the criteria of the National Committee for Clinical Laboratory Standards. PCR and sequence analyses were used to detect the blaIMP-1 and blaVIM-2 genes, and to determine the content and order of the resistance genes inserted in integron. RESULTS: Of 71 Acinetobacter spp. isolates collected from non-tertiary hospitals during 2002 and 2003, 60 isolates were A. baumannii, and 2, 4, and 5 isolates were Acinetobacter genomic species 3, 13TU, and A. lwoffii, respectively. The resistance rate of Acinetobacter spp. isolates to beta-lactams, aminoglycosides, and fluoroquinolones was high except for imipenem and meropenem. The presence of blaVIM-2 gene was found in one isolate, Acinetobacter genomic species 13TU, for which the MIC of imipenem was 8 mg/L; the blaVIM-2 gene of this strain was located on 3 kb class 1 integron with aacA7 and aadA1 genes. CONCLUSIONS: Among the tested agents, imipenem and meropenem retained greatest activity against Acinetobacter spp. isolates collected from non-tertiary hospitals. This is the first report of VIM-2-producing Acinetobacter genomic species 13TU strains with class 1 integron containing blaVIM-2 gene.

Purification of enolase from Candida albicans KNIH10 isolated in Korea and application of immunological diagnosis

We purified enolase from Candida albicans KNIH10 strain which was isolated from a clinical specimen in Korea. The purified enolase was used to detect anti-Candida antibodies in sera of patients with invasive candidiasis. For purification of enolase from the crude extract prepared by French pressure at 20,000 PSI, the fast performance liquid chromatography (FPLC) using DEAE-sepharose column was used. The elutes at 0.3-0.4 M NaCl in FPLC was purified with homogenity in SDS-PAGE and its enzymatic activity was confirmed in sera of invasive candidiasis with candidemia patient by immunoblotting. The purified enolase indicated no siggnal (100% specificity) in 40 normal human sera and 75% (6/8) sensitivity in sera of candidemic patients with suspicious invasive candidiasis by immunoblotting.

Nosocomial Infection Research Activities in Laboratory of Nosocomial Infection Pathogens in NIH of Korea / 병원감염관리

No Abstract available.

Identification and phylogenetic relationship of dermatophytes based on RFLP analysis and nucleotide sequence of internal transcribed spacer (ITS)1 in nuclear ribosome DNA

ITSI-5.8S-ITSII rDNA region was amplified from the reference strains and clinical isolates with ITS1 and ITS4 primers. These primers amplified DNA fragments of 550 bp in Microsporum audouinii and Trichophyton violaceum, 700 bp in Microsporum gypseum, Trichophyton mentagrophytes, Trichophyton rubrum, and Trichophyton tonsurans, and 750 bp in Microsporum ferreugineum and Microsporum canis. The restriction enzyme patterns of PCR products digested with 13 restriction enzyme including PstI were distint among the genera, whereas identical in the same species. Examination of the ITS (Internal Transcribed Spacers)1 nucleotide sequence revealed that there was the genetic difference in each genera and species. Phylogenetic relationship among each species showed that the Trichophyton mentagrophytes was more closely related Trichophyton tonsurans than Trichophyton rubrum, and Microsporum gypseum was less related than Microsporum spp.

Partial Purification and Characterization of 41 kDa Serine Proteinase from Culture Filtrate of Trichophyton tonsurans

Dermatophytes infect the human hair, skin, nail and cause the dermatophytosis. The extracellular and intracellular proteinases of the dermatophytes commonly occur in the genus Trichophyton like T. rubrum, T. mentagrophytes, and T. granulosum. These enzymes play a prominent role in growth, multiplication and infection of the host tissue. Extracellular proteinases have been purified from the species of Trichophyton and Microsporum. We purified the proteinase partially from the culture filtrate of the Trichophyton tonsurans through Mono-Q and Superose 12 column and investigated its biochemical and enzymatic characters. The molecular size of the proteinase was estimated to be 41 kDa by SDS-PAGE. And pI was 3.2. The optimal temperature and pH for an enzymatic activity were 27C and 7.5, respectively. The purified porteinase degraded the keratin, bovine serum albumin, hemoglobin. The serine proteinase inhibitor like PMSF and DFP inhibited the proteolytic activity of the purified enzyme whereas the cysteinase inhibitor did not. These results demonstrated that the purified proteinase is a serine proteinase and can contribute the tissue invasion.

Serological Immunity to Diphtheria among Korean Population / 감염

BACKGROUND: Diphtheria epidemics in Russia have spread to all the other independent states of the former Soviet Union and East European countries around 1990s. One of the most important measures in preventing diphtheria is to maintain high levels of immunity in the population. We studied the diphtheria antibody levels of 1,086 participants to investigate herd immunity in Korea. METHODS: The tested 1,086 serum specimens were collected from healthy individuals from September 1995 to March 1996. Diphtheria antitoxin titers were measured by a micro cell culture method using Vero cells. Antibody titer of 0.01 IU/ml to neutralize diphtheria toxin is an internationally accepted protective level. RESULTS: We studied the diphtheria antitoxin titer levels of 1,086 cases consisting of 579 males and 507 females. The proportion of protective antitoxin level to diphtheria is 69.2%. Diphtheria antitoxin levels showed no significant difference between males and females. The highest seropositive rate was observed in the 5 to 9-year old age group(95.8%). The seropositivity rate declined with age. The lowest seropositive rate was observed in the 20~39 years of age, maximally 43.4 %. Over 40 years of age, the seropositive rates increased again. CONCLUSION: The antibody titers in the Korean population declined from 95.8% to below 50% with age in the 1~39 year-old age group. To maintain the rate of population with protective antibodies to diphtheria, we recommend Td booster immunization to adults with low antitoxin titers and continuous survey for antitoxin titers.

C-Reactive Protein and Duration of Antibiotic Therapy in Neonatal Bacterial Infection

PURPOSE: To determine whether C-reactive protein (CRP) can be used as a parameter to assess the safety of discontinuing antibiotic therapy and allows a shorter course of therapy in neonates treated for suspected bacterial infection. METHODS: We have experienced 193 cases of suspected neonatal bacterial infection at Pusan Maryknoll Hospital. CRP levels were measured daily by immunonephelometry. Infants with initial CRP levels less than 0.8mg/dL were considered unlikely to be infected, and antibiotic therapy was stopped (group A; n=82). If three daily serial CRP levels were less than 0.8mg/dL, antibiotics were discontinued (group B; n=51). Sixty cases were treated for at least 7 days irrespective of CRP results (group C; n=60), and relapse rates of bacterial infection were compared between the three groups within one month after discharge. RESULTS: Within the one month follow-up period, two infants (2.4%) in group A, one infant (1.3%) in group B, two infants (3.3%) in group C received antibiotics for possible relapse of bacterial infection. The relapse rate in these groups was very low and frequency of a second course of antibiotic therapy between these groups was not different. CONCLUSION: These data allow considerably shorter courses of antibiotic therapy, safe discontinuation by three serial CRP measurement and show that CRP can be a key parameter for guiding the duration of antibiotic treatment. In addition, it would cut the length and cost of hospital stays and diminish the side effects of parenteral antibiotics.

C-Reactive Protein and Duration of Antibiotic Therapy in Neonatal Bacterial Infection

PURPOSE: To determine whether C-reactive protein (CRP) can be used as a parameter to assess the safety of discontinuing antibiotic therapy and allows a shorter course of therapy in neonates treated for suspected bacterial infection. METHODS: We have experienced 193 cases of suspected neonatal bacterial infection at Pusan Maryknoll Hospital. CRP levels were measured daily by immunonephelometry. Infants with initial CRP levels less than 0.8mg/dL were considered unlikely to be infected, and antibiotic therapy was stopped (group A; n=82). If three daily serial CRP levels were less than 0.8mg/dL, antibiotics were discontinued (group B; n=51). Sixty cases were treated for at least 7 days irrespective of CRP results (group C; n=60), and relapse rates of bacterial infection were compared between the three groups within one month after discharge. RESULTS: Within the one month follow-up period, two infants (2.4%) in group A, one infant (1.3%) in group B, two infants (3.3%) in group C received antibiotics for possible relapse of bacterial infection. The relapse rate in these groups was very low and frequency of a second course of antibiotic therapy between these groups was not different. CONCLUSION: These data allow considerably shorter courses of antibiotic therapy, safe discontinuation by three serial CRP measurement and show that CRP can be a key parameter for guiding the duration of antibiotic treatment. In addition, it would cut the length and cost of hospital stays and diminish the side effects of parenteral antibiotics.

Relationship between Chest Radiography and Cell-mediated Immunity in Mycoplasma pneumoniae Pneumonia

PURPOSE: Mycoplasma pneumoniae pneumonias have been one of the most common causes of lower respiratory tract diseases during childhood. It is suggested that pathologic changes seen in the lung tissues were the histologic expression of the host immune response. The aim of this study was to determine the relationship between the chest radiographic pattern of Mycoplasma pneumoniae pneumonia and the level of the cell-mediated immunity of the host. METHODS: Chest radiographic changes and the results of tuberculin skin test (5TU PPD) were studied during the acute stage of infection in 76 patients with Mycoplasma pneumoniae pneumonia. Chest radiographic findings were used to divide the patients into two groups; one group had a predominance of diffuse reticulonodular infiltration (Group A; n=40), while the remainings showed a predominance of segmental or lobar consolidation (Group B; n=36). A comparison was made between the two groups in terms of age, gender, total leukocyte and lymphocyte count, mycoplasma antibody titer, severity of pneumonia, and pleural effusion. RESULTS: Sixty out of 70 patients had negative tuberculin skin test and the positive rate of PPD reaction was higher in Group A (14/40) compared to Group B (2/40) (P0.05). CONCLUSION: Our study suggests that the cell-mediated immunity of patients with Mycoplasma pneumoniae pneumonia might influence the radiographic pattern of the pulmonary lesions.

Random Amplified Polymorphic DNA for Classification and Identification of Dermatophytes / 대한의진균학회지

BACKGROUND: Dermatophytoses are infections of keratinized tissues, that is, the epidermis, hair and nails, caused by a group of specialized fungi, the dermatophytes. Laboratory diagnoses of dermatophytes such as Tricophyton, Microsporum and Epidermophyton are made by microscopic examination and in vitro culture but they are either time consuming of lacking specificity. OBJECTIVE: In order to develop and apply more rapid and precise diagnostic tests for fungal pathogens to facilitate the improved identification of dermatophytes, we investigated random amplified polymorphism DNA for classification and identification of dermatophytes. METHODS: Amplification reactions were performed in volumes of 5011 containing 10mM Tris-HCl(pH 8.3), 50mM KCl, 1.5mM MgCl2, 0.01% (w/v), gelatin, 200mM dNTP mixture, 50pM primer, Taq polymerase (0.025 units/ microliter), DNA 0.001 microgram/microliter. The optimal condition to. PCR was 2 cycles (denaturing 94 degrees C 2min, annealing 33 degrees C 2min, extension 72 degrees C 4min), 40 cycles, and extension (72 degrees C 10min). RESULTS: RAPD showed interspecies polymorphism in but it had identical patterns in intraspecies. CONCLUSION: It was confirmed that RAPD PCR analysis with optimal conditions is a fast, economical and reproducible method for identification and classification of dermatophytes isolates.