The aim of this study is to characterize the epidemiological features of typhoid fever, categorized as class 1 notifiable disease in Korea and to analyze the recent change of antimicrobial resistance of Salmonella enterica serotype Typhi isolated nationwide. We retrospectively analyzed the 1,692 culture-proven cases from 1992 to 2000, using the data of the Korean National Institute of Health. The overall incidence of culture-proven typhoid fever was 0.41 per 100,000 population. It occurred all over the country, but the southeastern part of Korean peninsula had the higher incidence rate than other areas. There were several outbreaks suspected, of which two outbreaks were confirmed. The resistance rate against chloramphenicol showed mild increase, but the ampicillin, trimethoprim/sulfamethoxazole, kanamycin, or nalidixic acid resistance remained at the similar levels for the past 9 yr. There were 21 (1.3%) multidrug-resistant (MDR) strains isolated since 1992, and the number of those has increased. Two strains resistant to ciprofloxacin were first identified in Korea.
Ampicillin/pharmacology ; Anti-Bacterial Agents/pharmacology ; Chloramphenicol/pharmacology ; *Drug Resistance, Microbial ; Drug Resistance, Multiple ; Human ; Kanamycin/pharmacology ; Korea ; Nalidixic Acid/pharmacology ; Retrospective Studies ; Salmonella Infections/*epidemiology ; Salmonella enterica/*metabolism ; Seasons ; Serotyping ; Support, Non-U.S. Gov't ; Time Factors ; Trimethoprim/pharmacology

PURPOSE: As the incidence of non-typhoidal salmonella strains resistant to antibiotics has been increased, we attempted to investigate clinical aspects of non-typhoidal salmonella gastroenteritis and antibiotics resistance. METHODS: From January 2000 to June 2002, 99 children with positive stool culture of non-typhoidal salmonella were studied about clinical features, the incidence of antibiotics and multi-drug resistance and the difference of incidence of antibiotics resistance according to immune status. RESULTS: There were 66 males and 33 females. The majority of them were under 5 years of age (71%). 25 children were immunocompromised due to chemotherapy, steroid or immunosuppressive treatment. Serogroup D was the most common isolates (65%) followed by B (16%), C (8%) and E (8%). Resistance rate of 30% to ampicillin, 12% to chloramphenicol, 20% to trimethoprim- sulfamethoxazole (TMP-SMX), 11% to cefotaxime and 8% to cefixime were obtained. All isolates were susceptible to ciprofloxacine. Resistance rate to cefotaxime and cefixime in immunocompromised patients was 24% and 14.3% respectively, which were significantly higher compared to that in immunocompetent patients (6.8%, 5.6%, p<0.05). 11 isolates were resistant to three or more antibiotics. The incidence of multi-drug resistant isolates was significantly higher in immunocompromised patients (24%) than that of immunocompetent patients (6.8%). CONCLUSION: Because of the high prevalence of non-typhoidal salmonella strains resistant to ampicillin, chloramphenicol and TMP-SMX, third-generation cephalosporin might be the treatment of choice in non-typhoidal salmonella gastroenteritis. In particular, antibiotics should be carefully selected in immunocompromised patients because non-typhoidal salmonellas from them showed the higher incidence of antibiotic resistance and multi-drug resistance.
Ampicillin ; Anti-Bacterial Agents* ; Cefixime ; Cefotaxime ; Child ; Chloramphenicol ; Ciprofloxacin ; Drug Resistance, Microbial ; Drug Resistance, Multiple ; Drug Therapy ; Female ; Gastroenteritis* ; Humans ; Immunocompromised Host ; Incidence ; Male ; Prevalence ; Salmonella* ; Sulfamethoxazole ; Trimethoprim, Sulfamethoxazole Drug Combination

The frequency of antibiotic resistance among Salmonella enterica serovar Typhimurium has increased due to the transfer of multiple resistance factors. We detected the 13 antibiotic resistance genes by multiplex-PCR and compared with the results of phage typing and antibiotic disk diffusion for 49 S. typhimurium isolated from food-poisoning outbreaks in Seoul from 1999 to 2002. Resistance genes for tetracycline, streptomycin, ampicillin, sulfonamide, amino-glycoside-modifying enzyme, chloramphenicol, kanamycin, and trimethoprim were detected in 67.3%, 57.1%, 26.5%, 8.1%, 8.1%, 5%, 2.0%, and 0% of isolates, respectively. Overall 28 isolates (57.1%) possessed two or more antibiotic resistance genes. Class 1 integron carrying multidrug resistace genes, ant(3")-IaB, blaPSE, qacE delta1/sul, and tet G were amplified especially in only DT104 isolates. Among the related resistance genes for same antibiotics, strA and strB for streptomycin resistance were simultaneously detected but tetA and tetB for tetracycline were sporadically detected. DT 104 isolates contained only aadA2 and tetG.
Ampicillin ; Anti-Bacterial Agents ; Bacteriophage Typing ; Chloramphenicol ; Diffusion ; Disease Outbreaks ; Drug Resistance, Microbial ; Humans ; Integrons ; Kanamycin ; R Factors ; Salmonella enterica* ; Salmonella* ; Seoul* ; Streptomycin ; Tetracycline ; Trimethoprim

One hundred and thirty trimethoprim-resistant R plasmids derived from of Escherichia coli isolated from clinical specimens and feces of healthy collegians were examined for incompatibility, EcoRI endonuclease restriction fragment pattern, and Southern hybridization with DHFR I, II, III, V, and VII probe. 1. Most trimethoprim-resistant R plasmids were resistant to ampicillin, tetracycline, chloramphenicol, gentamicin, and kanamycin, and showed multiple drug resistance and various antimicrobial resistance patterns. 2. Trimethoprim-resistant R plasmids ranged from 90 to 50 kilobase and 42.3% of R plasmids tested were classified to incompatibilty group Inc FI, Inc FII or Inc FIV, 3. Among 48 random selected R plasmids from various origin, 14 R plasmids (including 9 of 14 Inc FII plasmids and 3 of 14 Inc FI plasmids) hybridized with DHFR VII oligonucleotide probe but others did not respond to any of DHFR probes used. 4. Most R plasmids showed various EcoRI endonuclease fragments and different reaction sites by Southern hybridization. Six plasmids showed identical or nearly identical molecular weight, EcoRI endonuclease fragment patterns and different sites of Southern hybridization. But 2 Inc FII plasmids derived from urine and feces showed identical pattern. These findings, if confirmed by further studies, suggest that normal flora E. coli can act as reservoir of resistant genes and, consequently, as a factor in the dissemination of these genes among enteric pathogens and need to be examined further.
Ampicillin ; Chloramphenicol ; Deoxyribonuclease EcoRI ; Drug Resistance, Multiple ; Escherichia coli* ; Escherichia* ; Feces ; Gentamicins ; Immunodeficiency Virus, Feline ; Kanamycin ; Molecular Biology* ; Molecular Weight ; Plasmids ; R Factors ; Tetracycline ; Trimethoprim Resistance* ; Trimethoprim*

OBJECTIVES: Few long-term studies have been conducted on the serotype and antibiotic resistance patterns of Salmonella speices (spp.) The aim of this study was to determine the serotypes and antibiotic resistance patterns of Salmonella spp. isolated at Jeollanam-do in Korea from 2004 to 2014. METHODS: A total of 276 Salmonella samples were evaluated. Serotyping was carried out according to the Kauffmann–White scheme. Antibiotic susceptibility was determined using the Vitek II system with an AST-N169 card. RESULTS: A total of 22 different serotypes were identified, and the major serotypes were Salmonella Enteritidis (116 strains, 42.0%) and Salmonella Typhimurium (60 strains, 21.7%). The highest resistance was observed in response to nalidixic acid (43.4%), followed by ampicillin (40.5%) and tetracycline (31.6%). Resistance to nalidixic acid was detected in 81.0% of S. Enteritidis. Multidrug resistance was detected in 43.3% of Salmonella spp. S. Enteritidis and S. Typhimurium presented the highest resistance (98.3%) and multidrug resistance rate (73.3%), respectively. The most highly observed antibiotic resistance pattern among Salmonella spp. in this study was ampicillin-chloramphenicol (14 strains, 5.7%). CONCLUSION: Overall, S. Enteritidis and S. Typhimurium showed higher antibiotic resistance than the other Salmonella serotypes tested in this study. Our study will provide useful information for investigating the sources of Salmonella infections, as well as selecting effective antibiotics for treatment.
Ampicillin ; Anti-Bacterial Agents ; Drug Resistance, Microbial* ; Drug Resistance, Multiple ; Jeollanam-do* ; Korea* ; Nalidixic Acid ; Salmonella enteritidis ; Salmonella Infections ; Salmonella typhimurium ; Salmonella* ; Serogroup* ; Serotyping ; Tetracycline

OBJECTIVETo investigate the molecule epidemic for 7 genes interrelated penicillin, erythromycin, tetracycline, vancomycin resistance of isolated Streptococcus pneumoniae (SP) in children at Suzhou area.

METHODS(1) Thirty-one pneumococcal isolates were collected from respiratory tract secretions of children with respiratory diseases from Nov 2002 to Apr 2003 at the Children's Hospital of Suzhou University (reference strain ATCC49619). (2) Penicillin susceptibility was determined by E-test, while erythromycin, tetracycline, vancomycin were determined by K-B disk. (3) The detecting of pbp2B, ermA/B, mefA, tetM, vanA, vanB genes by PCR, Sequencing pbp2B genes, Contrasting pbp2B DNA sequences among pneumococcal isolates and SP R6 [penicillin sensitive (www.ncbi.nlm.gov/nucleotide, NC-003098)].

RESULTSOf thirty-one isolates studied, the results were shown as follows; (1) Penicillin sensibility 38.7% (n = 12), penicillin resistance 61.3% (n = 19), pbp2B mutation 64.5% (n = 20); (2) Erythromycin sensibility 9.7% (n = 3), erythromycin resistance 90.3% (n = 28), ermA/B 71% (n = 22), mefA 32.1% (n = 10), ermA/B + mefA 87.1% (n = 27); (3) Tetracycline sensibility 9.7% (n = 3), tetracycline resistance 90.3% (n = 28), tetM 90.3% (n = 28); (4) Vancomycin sensibility 100% (n = 31), vanA, vanB all 0%.

CONCLUSIONAmong pneumococcal isolates at our area, penicillin, erythromycin, tetracycline resistance were high, vancomycin was sensitive. Detecting 7 genes interrelated penicillin, erythromycin, tetracycline, vancomycin resistance expressed genotypies for antibiotic resistances in pneumococcal isolates.

Anti-Bacterial Agents ; pharmacology ; Child ; China ; epidemiology ; DNA, Bacterial ; genetics ; Drug Resistance, Multiple, Bacterial ; genetics ; Erythromycin ; pharmacology ; Female ; Humans ; Male ; Microbial Sensitivity Tests ; Molecular Epidemiology ; Penicillin Resistance ; genetics ; Pneumococcal Infections ; epidemiology ; microbiology ; Streptococcus pneumoniae ; drug effects ; genetics ; isolation & purification ; Tetracycline Resistance ; genetics ; Vancomycin ; pharmacology

BACKGROUND: Pneumococcus is the most common cause of acute otitis media, community acquired pneumonia and invasive bacterial diseases in children. Ninety serotypes have been identified, and the distribution differs according to geographic area and ages. The 7 valent pneumococcal protein conjugate vaccine is used widely. To evaluate the efficacy of the vaccine, it is essential to investigate the distribution of the pneumococcal serotypes. MATERIALS AND METHODS: The serotypes and antibiotic resistance of the pneumococcus isolated from 308 patients at Shinchon Severance hospital from September of 2001 to July of 2005 were analyzed. RESULTS: The pneumococcci were isolated mostly from sputum and blood, and ear discharge in the descending order. Serotyping was possible in 265 cases, and the distribution of serotypes were 19F (16.2%), 19A (12.8%), 23F (8.7%), 6B (7.9%), and 6A (7.2%). Fifty two cases were isolated from those patients less than 16 years of age and the distribution of serotypes was 19F, 19A, 23F, 14, 6B, 6A and 4. Resistance to penicillin was 64.6% in all cases and 67.3% in children. The more common serotype showed the higher rate of penicillin resistance. Multi-drug resistance was demonstrated in 64.7%. Forty three percent of the total identified serotypes were included in the 7 valent pneumococcal conjugate vaccine. And 61.5% of the serotypes identified in children were included in the vaccine. CONCLUSION: The 7 valent vaccine may be used effetively in Korea. But, further study is needed to address serotype switching after the use of the protein conjugated vaccine, which has been reported in other countries.
Anti-Bacterial Agents ; Child ; Drug Resistance, Microbial ; Drug Resistance, Multiple ; Ear ; Humans ; Korea ; Otitis Media ; Penicillin Resistance ; Penicillins ; Pneumonia ; Serotyping ; Sputum ; Streptococcus pneumoniae* ; Streptococcus*

BACKGROUND: Pneumococcus is the most common cause of acute otitis media, community acquired pneumonia and invasive bacterial diseases in children. Ninety serotypes have been identified, and the distribution differs according to geographic area and ages. The 7 valent pneumococcal protein conjugate vaccine is used widely. To evaluate the efficacy of the vaccine, it is essential to investigate the distribution of the pneumococcal serotypes. MATERIALS AND METHODS: The serotypes and antibiotic resistance of the pneumococcus isolated from 308 patients at Shinchon Severance hospital from September of 2001 to July of 2005 were analyzed. RESULTS: The pneumococcci were isolated mostly from sputum and blood, and ear discharge in the descending order. Serotyping was possible in 265 cases, and the distribution of serotypes were 19F (16.2%), 19A (12.8%), 23F (8.7%), 6B (7.9%), and 6A (7.2%). Fifty two cases were isolated from those patients less than 16 years of age and the distribution of serotypes was 19F, 19A, 23F, 14, 6B, 6A and 4. Resistance to penicillin was 64.6% in all cases and 67.3% in children. The more common serotype showed the higher rate of penicillin resistance. Multi-drug resistance was demonstrated in 64.7%. Forty three percent of the total identified serotypes were included in the 7 valent pneumococcal conjugate vaccine. And 61.5% of the serotypes identified in children were included in the vaccine. CONCLUSION: The 7 valent vaccine may be used effetively in Korea. But, further study is needed to address serotype switching after the use of the protein conjugated vaccine, which has been reported in other countries.
Anti-Bacterial Agents ; Child ; Drug Resistance, Microbial ; Drug Resistance, Multiple ; Ear ; Humans ; Korea ; Otitis Media ; Penicillin Resistance ; Penicillins ; Pneumonia ; Serotyping ; Sputum ; Streptococcus pneumoniae* ; Streptococcus*

OBJECTIVE: To investigate the mechanisms by which MecA gene expression leads to β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA), and to study the resistance mechanism of MRSA at the molecular level. METHODS: A variety of molecular biological techniques were employed, including screening MRSA using cefoxitin paper disk method, extraction of MRSA mRNA, reverse transcription into cDNA, real-time fluorescence PCR for quantitation of MecA gene expression, and agar dilution method for assessment of minimum inhibitory concentrations in MRSA treated with cefoxitin, oxacillin, vancomycin, or linezolid. RESULTS: According to the level of resistance of MRSA to cefoxitin, 40 MRSA strains were divided into a low resistance group (n=12), a middle resistance group (n=15), and a high resistance group (n=13). The expression level of the MecA gene in the low resistance group, the middle resistance group, and the high resistance group was 58.87±30.30, 363.37±200.05, and 1257.72±446.63, respectively. MRSA resistance to cefoxitin and oxacillin was 100%; MRSA resistance to vancomycin or linezolid could not be detected. For all 40 MRSA strains the MIC90 for vancomycin was 2.0 μg/mL. CONCLUSION MecA gene expression levels may correlate with the MRSA level of resistance to cefoxitin within a certain range of concentration.
Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; metabolism ; Cefoxitin ; pharmacology ; Drug Resistance, Multiple, Bacterial ; Methicillin-Resistant Staphylococcus aureus ; drug effects ; genetics ; metabolism ; Microbial Sensitivity Tests ; methods ; Oxacillin ; pharmacology ; Penicillin-Binding Proteins

OBJECTIVETo investigate the SCCmec genotyping, subtype and antimicrobial susceptibility tests in methicillin resistant staphylococcus aureus to guide the clinical treatment and provide the proof for molecular epidemiology.

METHODSTo detect mecA gene and SCCmec genetyping and subtype in 50 MRSA by PCR. According to CLSI's guideline, antimicrobial susceptibility tests were performed with disk diffusion.

RESULTSAll 50 MRSA had mecA genes. 45 strains were SCCmec III types; 3 strains were SCCmec III A types; 2 strains were SCCmec II types. There were no SCCmec I and SCCmec IV types. SCCmec II, SCCmec III and SCCmec III A type strains were all multiresistant.

CONCLUSION50 MRSA are all multiresistant. SCCmec III are the main types.

Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; China ; epidemiology ; Drug Resistance, Multiple, Bacterial ; Genotype ; Humans ; Methicillin-Resistant Staphylococcus aureus ; classification ; drug effects ; genetics ; isolation & purification ; Microbial Sensitivity Tests ; Penicillin-Binding Proteins ; Phylogeny ; Staphylococcal Infections ; epidemiology ; microbiology