• Journal of Yeungnam Medical Science
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• v.6 no.1
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• pp.59-68
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• 1989

Ceftizoxime sodium is a new synthetic ${\beta}$-lactam antibiotic combining potent antibacterial activity with high stability to a wide range of bacterial ${\beta}$-lactamase. This experiment was achieved to evaluate the antibacterial activities of ceftizoxime sodium againist Gram negative enteric bacteria isolated from in outpatient visiting Yeungnam university hospital and to study the emergence of drug induced bacterial varients which resist to ceftizoxime in vitro. The antibacterial activity of the ceftizoxime was compared with that of antibiotics and its effect on population of normal intestinal flora in mice was observed. The results are summarized as follows : 1. Highly effective antibacterial activity of ceftizoxime against Gram negative enteric bacilli was demonstrated and this antibacterial activity was superior to that of ampicillin. 2. Several test strains shows multiple antibiotic resistence. Among 15 strains of Escherichia coli, 1 strain was resistent to ampicillin, cefadroxyl, gentamicin, tetracycline, and 2 strains were resistent to ampicillin, cefadroxyl, tetracycline, five strains of Escherichia coli and Enterobacter cloacae was resistent to amplicillin, tetracycline and Shigella dysenteria was resistent to ampicillin, gentamicin, tetracycline. 3. The frequency of in vitro emergence of resistent varients among ceftizoxime sensitive bacteria in the presence of increasing concentrations of the compound was found to be low. 4. Plasmid was isolated in 6 of 9 strains (6 strains of Escherichia coli, Shigella dysenteriae, Enterobacter cloaceae and Salmonella typhi) That showed different antibiotic resistance. They were 5 strains of Escherichia coli and 1 strain of Shigella dysenteriae. However, plasmid could not be considered as a hallmark for antibiotic resistance by this. Further studies with curing experiment are to be accomplished for this purpose. 5. Changes in the bacterial count of normal intestinal flora following 25mg/kg/day administration of ceftizoxime over S consecutive days were not significant. In conclusion, ceftizoxime appeared to be a drug of choice in the treatment of Gram negative enteric bacilli infection.

• Korean Journal of Microbiology
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• v.50 no.2
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• pp.114-118
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• 2014

A total of 122 ESBL-producing intestinal bacteria were collected from regional hospitals in the Chungcheong area. Combination disk test (CDT) was performed for antimaicrobial susceptability using cefotaxime and cefotaxime/clavulanate according to Clinical Laboratory Standard Institute (CLSI). Mutiplex PCR using specific primers was performed for a detection of ESBL-genotypes and enterobacterial repetitive intergenic consensus (ERIC)-PCR was carried out for the tracking of molecular epidemiology. In the confirmation test using CDT, 73 out of 76 (96.1%) ESBL-producing Escherichia coli and 43 out of 46 (93.4%) ESBL-producing Klebsiella pnemoniae were positive. In the multiplex PCR, 60.5% of E. coil were positive for CTX-M-2 type gene and 56.5% of K. pneumoniae were positive for VEB -1 type gene. In the ERIC-PCR, E. coil isolates formed 5 clusters and K. pneumoniae isolates were grouped into 4 clusters depending on region. Genotypes of clinical isolates are useful for detection and differentiation of ESBL producing intestinal bacteria. The ERIC-PCR method is thought to be helpful for establishing a regional surveillance system for infection due to its formation of different clusters depending on region.

• Journal of fish pathology
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• v.32 no.2
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• pp.97-104
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• 2019

The purpose of this study was to investigate the antimicrobial resistance and resistance transfer of Vibrio parahaemolyticus and Morganella morganii isolated from fish products purchased from fish markets in Yeosu April - December 2017. These bacteria were identified by biochemical test and PCR results, and the transfer of antimicrobial resistance was confirmed by the broth mating method. To isolate the transconjugants formed during conjugation, TSA medium containing 50 ㎍/ml of ampicillin (AMP), and 150 ㎍/ml of streptomycin (SM) or 30 ㎍/ml of oxytetracycline (OT) was used. M. morganii isolates showed low susceptibility to AMP, amoxicillin (AML), and colistin (CT), erythromycin, OT, and tetracycline, compared to V. parahaemolyticus resistance to AMP, AML, and CT. The conjugation of V. parahaemolyticus or M. morganii with Escherichia coli resulted in the separation of V. parahaemolyticus and M. morganii showing SM resistance as transconjugants. Meanwhile, Edwardsiella tarda transconjugants showing AMP and AML resistance were obtained from the broth mating of V. parahaemolyticus and E. tarda. But the transfer of the VPA0477 which is a β-lactamase gene of V. parahaemolyticus was not confirmed. These results suggest that resistance transfer between pathogenic bacteria is bidirectional and progresses in a wide variety of patterns.

• Childhood Kidney Diseases
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• v.19 no.2
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• pp.148-153
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• 2015

Purpose: We investigated trends in antibiotic resistance for gram-negative bacteria in infants with a urinary tract infection (UTI) over 15 years at a single institution. Methods: A retrospective chart review was conducted for children younger than 24 months who visited the emergency room and were diagnosed with a UTI between January 2000 and December 2014. We selected urine culture data that grew Escherichia coli and Klebsiella pneumoniae. Baseline clinical information and results of antimicrobial susceptibility tests were analyzed by dividing the 15-year study time frame into three periods (A: 2000-2004, B: 2005-2009, and C: 2010-2014). Results: During the study period, 478 applicable children were identified (E. coli, 89.7% and K. pneumoniae, 10.3%). Antibiotic resistance to third-generation cephalosporins was increased from period A to period C (A, 2.1%; B, 8.3%; C, 8.8%; P=0.025). Resistance to quinolones also showed a steady pattern during periods A to C, although it was not statistically significant (A, 7.9%; B, 9.7%; C, 12.4%; P=0.221). The incidence of Extended-spectrum ${\beta}$-lactamase (ESBL)-producing gram-negative bacteria increased from period A to period C (A, 1.4%; B, 7.6%; C, 8.2%; P=0.012). Conclusion: This study revealed that the common uropathogens E. coli and K. pneumoniae experienced increasing resistance rates against third-generation cephalosporins and a constant antibiotic resistance to quinolones in children younger than 24 months. We also showed a recent increased incidence of ESBL-producing gram-negative bacteria in patients with community-acquired UTIs. Therefore, it is necessary to actively surveil resistance in order to properly select empirical antibiotics.

• Journal of Yeungnam Medical Science
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• v.16 no.2
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• pp.270-276
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• 1999

Background: Extended-spectrum ${\beta}$-lactamases(ESBL) are enzymes that confer resistance to oxyimino-${\beta}$-lactams as well as to penicillins and cephalosporins. Strains of Klebsiella pneumoniae and Escherichia coli that produce ESBL have been increasingly prevalent in many countries. The purpose of this study was to investigate the ESBL production rate of K. pneumoniae and E. coli at the in Yeungnam University Medical Center. Materials and Methods: Thirty-one isolates of K pneumoniae and twenty-five isolates of E. coli were examined for ESBL by double disk synergy test, using 20/$10{\mu}g$ ticarcillin/clavulanic acid and $30{\mu}g$ oxyimino-${\beta}$-lactam(ceftazidime, ceftaxime, ceftriaxone and aztreonam) disks. Results: Fifty-two percent of K. pneumoniae and sixteen percent of E. coli isolates revealed double disk synergism. Majority of ESBL-producing strains(fifty-five percent) were isolated from patients in the intensive care unit. Conclusion: ESBL production of K. pneumoniae and E. coli were also common at the Yeungnam University Medical Center and pose a serious problem for antimicrobial therapy.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2000.04a
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• pp.3-6
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• 2000

Antimicrobial resistance has been a well-recognized problem ever since the introduction of penicillin into clinical use. History of antimicrobial development can be categorized based on the major antibiotics that had been developed against emerging resistant $pathogens^1$. In the first period from 1940 to 1960, penicillin was a dominating antibiotic called as a "magic bullet", although S.aureus armed with penicillinase led antimicrobial era to the second period in 1960s and 1970s. The second stage was characterized by broad-spectrum penicillins and early generation cephalosporins. During this period, nosocomial infections due to gram-negative bacilli became more prevalent, while those caused by S.aureus declined. A variety of new antimicrobial agents with distinct mechanism of action including new generation cephalosporins, monobactams, carbapenems, ${\beta}$-lactamase inhibitors, and quinolones characterized the third period from 1980s to 1990s. However, extensive use of wide variety of antibiotics in the community and hospitals has fueled the crisis in emerging antimicrobial resistance. Newly appeared drug-resistant Streptococcus pneumoniae (DRSP), vancomycin-resistant enterococci (VRE), extended-spectrum ${\beta}$-lactamase-producing Klebsiella, and VRSA have posed a serious threat in many parts of the world. Given the recent epidemiology of antimicrobial resistance and its clinical impact, there is no greater challenge related to emerging infections than the emergence of antibiotic resistance. Problems of antimicrobial resistance can be amplified by the fact that resistant clones or genes can spread within or between the species as well as to geographically distant areas which leads to a global concern$^2$. Antimicrobial resistance is primarily generated and promoted by increased use of antimicrobial agents. Unfortunately, as many as 50 % of prescriptions for antibiotics are reported to be inappropriate$^3$. Injudicious use of antibiotics even for viral upper respiratory infections is a universal phenomenon in every part of the world. The use of large quantities of antibiotics in the animal health industry and farming is another major factor contributing to selection of antibiotic resistance. In addition to these background factors, the tremendous increase in the immunocompromised hosts, popular use of invasive medical interventions, and increase in travel and mixing of human populations are contributing to the resurgence and spread of antimicrobial resistance$^4$. Antimicrobial resistance has critical impact on modem medicine both in clinical and economic aspect. Patients with previously treatable infections may have fatal outcome due to therapeutic failure that is unusual event no more. The potential economic impact of antimicrobial resistance is actually uncountable. With the increase in the problems of resistant organisms in the 21st century, however, additional health care costs for this problem must be enormously increasing.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1377-1383
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• 2006

Among 46 Acinetobacter baumannii isolates collected in 2004, two imipenem-resistant isolates were obtained from clinical specimens taken from patients hospitalized in Busan, Republic of Korea. Two carbapenemase-producing isolates were further investigated to determine the mechanism of resistance. These isolates were analyzed by antibiotic susceptibility testing, microbiological tests of carbapenemase activity, determination of pI, transconjugation test, enterobacterial repetitive consensus (ERIC)-PCR, and DNA sequencing. Two cases of infection by A. baumannii producing the IMP-1 ${\beta}$-lactamase were detected. The isolates were characterized by a modified cloverleaf synergy test and EDTA-disk synergy test. Isoelectric focusing of crude bacterial extracts revealed nitrocefin-positive bands with a pI value of 9.0. PCR amplification and characterization of the amplicons by direct sequencing indicated that the isolates carried a $bla_{IMP-l}$ determinant. The isolates were characterized by a multidrug resistance phenotype, including penicillins, extended-spectrum cephalosporins, carbapenems, and aminoglycosides. These results indicate that the observed imipenem resistance of two Korean A. baumannii isolates was due to the spread of an IMP-1-producing clone. Our microbiological test of carbapenemase activity is simple to screen class B metallo-${\beta}$-lactamase-producing clinical isolates to determine their clinical impact and to prevent further spread. This study shows that the $bla_{IMP-l}$ resistance determinant, which is emerging in Korea, may become an emerging therapeutic problem, since clinicians are advised not to use extended-spectrum cephalosporins, imipenem, and aminoglycosides. This observation emphasizes the importance of having effective control measures in Asian hospitals, such as early detection of colonized patients, isolation procedures, and a judicious use of antibiotics.

• The Korean Journal of Zoology
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• v.27 no.2
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• pp.103-116
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• 1984

The structural gene of rabbit hemoglobin was cloned into Pst I site of pBR322 in E. coli. The complementary DNA (cDNA) was synthesized from rabbit globin mRNA with avian myeloblastosis viral reverse transcriptase, and then RNA was destroyed at pH 11. The double stranded cDNA was synthesized with both Klenow fragment of E. coli DNA polymerase I and reverse transcriptase and then the hairpin loop was opened with Sl nuclease. Double stranded cDNA was subsequently tailed with dCTP and annealed to dGMP-tailed vector DNA. After transformation and initial screening of appropriate clones by plasmid size, the cloned colonies were identified by in situ colony hybridization using by plasmid size, the cloned colonies were identified by in situ colony hybridization using $[^32P]$-labeled cDNA probes and characterized the inserts with restriction endonucleases. The expression of cloned globin gene was investigated by standard radioimmunoassay using rat anti-rabbit Hb serum as primary antibody and goat antirat IgG serum as secondary antibody. The result suggested that the chimeric proteins (the part of $\\beta$-lactamase from the vector pBR322 and globin from rabbit) were supposedly produced in E. coli and the product had the antigenic determinant of rabbit hemoglobin.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2516-2522
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• 2009

The data which analyze the results of blood cultures are crucial basic information of the empirical therapy for patients with infection since the patterns of the species of microorganism isolated from blood and the results of antibiotic susceptibility test vary depending upon patients general features. Especially, in case of ESBL-producing bacteria, there is a close relation with use of antibiotics. Therefore, we carried out the research with the results of blood culture and antibiotic. 1. Total 39,305 cases of blood culture samples were investigated and positive patients of 2,216 (20.0%) were found. Among those, there were 40 patients with ESBL positive, and blood culture positive samples were 4,798 (12.2%). ESBL positive bacteria were found in 86 samples (including double checked culture bacteria). 2. The majority of ESBL producing bacteria were E. coli, K. pneumoniae and K. oxitoca as ordering based on the number. 3. The research showed the results that there were more females than male with the bacterias, more E. coli in over 50 years old aged group than other bacterias, more K. pneumoniae and K.oxitoca in less 1 year old aged group than other bacterias and largest numbers of patients with 13 patients (32.5%) in Chungcheongnam-do province were found. 4. The most common ESBL producing bacteria were E. coli throughout 3 years, but K, pneumoniae and K. oxitoca were also fairly found. Interestingly, E. coli was highly found in over 50 years old patients.

• Korean Journal of Veterinary Service
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• v.30 no.4
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• pp.505-510
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• 2007

This study was conducted to detect ${\beta}$-lactam antibiotic-resistant genes in the 400 E coli isolates from porcine fecal samples in Korea by a DNA chip. The DNA chip contains the specific probe DNAs of the ${\beta}$-lactam antibiotic-resistant genes that had been labeled with a mixture of primer set designed to amplify specific genes (PSE, OXA, FOX, MEN, CMY, TEM, SHV, OXY and AmpC) using a multiplex polymerase chain reaction (PCR). Of 400 isolates 339 contained at least one ${\beta}$-lactamases gene. Resistance to ${\beta}$-lactamases was mediated mainly by AmpC (n = 339, 100%), and followed by TEM (n = 200, 59.0%), CMY (n = 101, 29.8%), PSE (n = 30, 8.9%) and both OXA and SHV genes (n = 20, 5.9%), while the FOX, MEN and OXY genes were not detected. The other sixty-one did not contain any ${\beta}$-lactamase genes even though they were resistant to antimicrobial drugs. In conclusion, the DNA chip system can be used as a rapid and reliable method for detecting of ${\beta}$-lactamases genes, which will help veterinarians select the antibiotics for monitoring and treating of animal diseases.