• Clinical and Experimental Pediatrics
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• v.49 no.8
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• pp.882-888
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• 2006

Purpose : Bacteremia is one of the major concerns in the treatment of pediatric cancer patients. This study was to determine the etiologic agents and the pattern of antibiotic susceptibilities in a single tertiary medical center. Methods : We retrospectively reviewed the medical records of the cases of bacteremia in pediatric cancer patients from 1998 to 2005 in Keimyung University Dongsan Medical Center. Results : There were 62 cases of bacteremia from 44 patients. Gram-positive organisms(48.3%) were more common than gram-negative organisms(38.7%) or fungi(13%). Among gram-positive organisms, Staphylococcus epidermidis was the most common etiologic agent(63.3%), followed by Staphylococcus aureus(16.7%), ${\alpha}$-hemolytic Streptococcus(16.7%), and Streptococcus mitis(3.3%). Among gram-negative organisms, Alcaligenes xylosoxidans was the most common agent(41.7%) and the other organisms were Klebsiella pneumoniae(20.8%), Stenotrophomonas maltophilia(12.5%), Acinetobacter baumanii(8.2%), etc. In febrile neutropenic patients, however, K. pneumoniae was the most common cause of gram-negative bacteremia. All of the isolated K. pneumoniae in our center produced extended-spectrum beta-lactamase and were related with high mortality. S. aureus, S. epidermidis, and Streptococcus species were all susceptible to vancomycin and teicoplanin. Most staphylococci were resistant to penicillin and oxacillin. Most of the gram-negative organisms were susceptible to imipenem. Conclusion : Gram-positive organisms were more commonly isolated than gram-negative organisms in pediatric cancer patients like other studies. We could obtained valuable information on the choice of proper antibiotics in our institution. Further studies will be needed to explain the prevalence of A. xylosoxidans in our center.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.286-294
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• 2004

Between 1997 and 1998 in Korea, 56 isolates of Escherichia coli were obtained from pig suffering diarrhea. Among those, 38 isolates that showed the hemolytic activity, antimicrobial resistance, and toxin production were studied. Among 38 isolates, thirty-six isolates $(94.7\%)$ were resistant to tetracycline, 27 isolates $(71.0\%)$ were resistant to ampicillin, 26 isolates $(68.4\%)$ were resistant to chloramphenicol, and 21 isolates $(55.2\%)$ were resistant to trimethoprim, while none was resistant to aztreonam, amikacin, and norfloxacin. Among these iso­lates, 21 isolates $(55.3\%)$ were multiple drug resistant to at least four different class antimicrobial agents. Extended spectrum $\beta-lactamase$ producing isolates were not detected in the double disk synergy test. In these hemolytic Escherichia coli, heat-stable enterotoxin $(89.5\%)$ was the most prevalent toxin, followed by vero­toxins $(47.4\%),$ and then heat-labile enterotoxin $(31.6\%).$ Except 8 isolates $(21.0\%)$ which produced ST only, 12 isolates $(31.6\%)$ produced ST and LT, 13 isolates $(34.2\%)$ produced ST, VT, and VTe, and 5 isolates $(13.2\%)$ produced VT and VTe. However, none produced all 4 types of toxin, simultaneously. The predominant serotype could not be determined by the agglutination method. Sixteen isolates $(42.1\%)$ were strongly adhered to T-24 bladder cell and 17 isolates $(44.7\%)$ were to Caco-2 intestinal cell. Especially, 11 strains $(28.9\%)$ were evaluated as strongly adhesive to both T-24 cells and Caco-2 cells. Genes for toxin and the antimicrobial resistance were transferred to clinical isolates of Escherichia coli from human urine by the filter mating method. Results suggest the possibility that antimicrobial resistance and toxin can be transferred from animals to humans by direct con­tact of resistant bacteria as well as gene transfer, although there was no correlation between toxin production, adherent activity, and antimicrobial resistance among hemolytic E. coli isolated from pig suffering diarrhea.

• Clinical and Experimental Pediatrics
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• v.49 no.7
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• pp.777-783
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• 2006

Purpose : Urinary tract infection(UTI) is one of the most frequent infections in children. E. coli is the most frequent etiological micropathogen in pediatric community UTI, and E. coli has developed resistance to many antibiotics, highlighting the need for regular surveys of this organism resistant patterns in the community. The aim of this study was to determine the oral antibiotic susceptibility patterns of E. coli, isolated from pediatric patients with uncomplicated community acquired UTI. Methods : E. coli isolates, obtained from pediatric patients with uncomplicated community acquired UTI between October in 2004 to September in 2005. And minimal inhibitory concentrations(MICs) of oral aminopenicillins and beta-lactamase inhibnitors(ampicillin, amoxacillin, ampicillin-sulbactam), oral cephalosporins(cefaclor, cefixime) and sulfa drug(trimethoprime-sulfamethoxazole) were performed according to the National Committee for Clinical Laboratory Standards(NCCLS) guide line. Results : Total 211 organisms were isolated from pediatric out-patients with community UTI. E. coli was the most common organism(89 percent), followed by E. fecalis, Proteus species, S. aureus, M. morganii, and P. aeruginosa. The resistant rates of aminopenicillins and beta-lactamase inhibitors, cefaclor and sulfa drug to E. coli were very high. But, the resistant rate of cefixime was markedly low, and ESBL strains were isolated with small rates. Conclusion : Our study results suggest that aminopenicillins, cefaclor and sulfa drug may not be useful as first line empirical antibiotics to treat pediatric patients with community UTI in Korea. But, 3rd generation cephalosporin such as cefixime can be used as effective second line antibiotics after primary treatment failure, also may be useful as an empirical first line antibiotic. Finally, we conclude that a continuous surveillance study to monitor susceptibility patterns of E. coli in community UTI will be needed for the standard guide lines of empirical oral antibiotic treatment.

• Journal of Preventive Medicine and Public Health
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• v.16 no.1
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• pp.41-50
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• 1983

The incidence of sexually transmitted disease, especially gonorrhoea has risen despite the progress in its diagnosis and treatment. For the effective control programs of sexually transmitted disease, it should be required socio-medical approaches. A study on gonorrhoea and penicillinase-producing Neisseria gonorrhoeae(PPNG) was conducted in Jeonju and Kunsan area from March, 1982 through August, 1982. The 221 entertrainers were studied in order to determine the prevalences of gonorhoea and PPNG. Socio-demographic informations of the entertainers were obtained by interviewing them. Gonococci were cultured on Thayer-Martin enrichment media for isolation, and PPNG was confirmed using beta-lactamase reagent ($PADAC^{tm}$ Beta-Lactamase Test Strips, Galbiochem-Behring). The results of the study are summarized as follows; 1. The average age of the entertainers studied was $26.1{\pm}4.7$ years. 2. The average years of working in entertaining business was $2.4{\pm}1.4$ years, and the average income per month was $239,592{\pm}90,480$ won. On the education level, 70.6% of the entertainers were middle or high school graduates 3. 47.5% of the entertainers were using contraceptives. 90.5% have experienced artificial abortion. 4. 37(16.7%) out of 221 entertainers were revealed to gonorrhoea, and 13 (35.1%) of gonorrhoea patients were by PPNG. 5. The prevalence rates of gonorrhoea and the proportion of PPNG by age were not significant statistically. Meanwhile, the colelations between the rates of gonorrhoea and education, frequency of love-making with customers and type of sexual partner were highly significant statistically. 6. 37 strains of gonococci isolated were almostly resistant to several antimicrobial agents, especially amikacin, clindamycin and chloramphenicol. Furthermore PPNG strains were completely resistant to not only above drugs but also penicillin.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.77-84
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• 2015

This study was conducted to investigate the characteristics of antibiotic resistant E. coli. its antibiotic susceptibility and pathogenicity were analyzed via molecular convergence technique, for the relationship of antibiotic susceptibility and pathogenicity. The 60 isolated strains consisted of ESBL(+)(8) and ESBL(-)(52) strains. The ESBL(+)(8) strains consisted of 2 strains without a pathogenic gene, stb(3), flich7(1), and flich7-eae(2). The ESBL(-)(52) strains consisted of 26 strains without a pathogenic gene, stx1(3), stb(10), flich7(2), eae(2), stx1-flich7(2), stx1-stb(4), flich7-stb(2), and flich7-stb-eae(1). In conclusion, antibiotic resistance is increasingly, Focused on molecular convergence, showed the correlation of pathogenicity with antibiotic resistance was poor. However, It will be able to find the exact pathogenic factor in the future through convergence technique including the analysis of virulence genes.

• Microbiology and Biotechnology Letters
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• v.34 no.4
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• pp.342-351
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• 2006

The aim of this study was to survey susceptibilities of Escherichia coli and Klebsiella pneumoniae isolates against cefotaxime and to determine the prevalences of CTX-M type extended-spectrum $\beta$-lactamases (ESBLs) producing E. coli and K. pneumoniae in Korea. During the period of February to July, 2005, 153 E. coli and 52 K. neumoniae isolates were collected from 2 hospitals in Busan. Antimicrobial susceptibilities to cefotaxime were tested by the disk diffusion method. ESBL production of E. coli and K. pneumoniae was determined by the double disk synergy test. MICs of $\beta$-lactam antibiotics were determined by the agar dilution method. Blac$_{CTX-M}$ genes of the organism were detected by PCR. Among 153 isolates of E. coli and 52 isolates of K. neumoniae, 27 (17.6%) and 25 (48.0%) were intermediate or resistant to cefotaxime, respectively. Twenty-three (15.0%) isolates out of 153 E. coli and 13 (25.0%) out of 52 K. neumoniae isolates showed positive results for ESBL by the double disk synergy test. Twenty isolates out of 23 ESBL producing E. coli and 12 out of 13 ESBL producing K. neumoniae isolates harbored biacTx-M gene,11 of ESBL producing E. coli and 12 of ESBL producing K. neuinoniae isolates harbored bla$_{CTX-M}$ gene, 11 of the ESBL producing E. coli and 2 of ESBL producing K. neumoniae isolates harbored bla$_{TEM}$ gene, and 1 of the ESBL producing E. coli and 12 of ESBL producing K. neumoniae isolates harbored bla$_{SHV}$ gene. E. coli and K. neumoniae isolates producing CTX-M-type ESBLs were not uncommon in Korea. It is thought that continuous survey are necessary for inspecting the spread and novel variants of CTX-M-type ESBL genes. Further me]'e investigation and research on ESBL producing strains are needed in order to prevent the spread of resistant bacteria.

• Pediatric Infection and Vaccine
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• v.17 no.1
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• pp.30-35
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• 2010

Purpose : We investigated the causative organism and its antibiotic susceptibility of community acquired urinary tract infection (UTI) in children at a secondary hospital to test the adequacy of the current guidelines. Methods : Children diagnosed with UTI at the Department of Pediatrics, Kwandong University MyMyongji Hospital by pyuria and bacterial growth of greater than $1.0{\times}10^5CFU/mL$ on clean catch midstream urine from January 2005 to December 2008 were studied retrospectively. The epidemiologic data, causative organism, and the antibiotic susceptibility were analyzed. Results : Sixty two children were diagnosed with sixty four cases of UTI's. Two bacteria were isolated in one case and thus data on 65 urine cultures were analyzed. The male:female ratio was 1.6:1 and 78.1% were less than 12 months of age. Escherichia coli was the predominant cause consisting of 53 cases (82.8%) of the cases. K. pneumoniae (5), Enterobacter (4), Enterococcus (1), $\beta$-streptococcus (1), Diphtheroides (1) were isolated. The antibiotic resistance of E. coli were as follows; ampicillin 69.8%, cefotaxime 1.9%, gentamicin 15.1%, amikacin 0.0%, levofloxacin 1.9%, and trimethoprim/sulfamethoxazole 26.4 %. Only one case of the E. coli was extended spectrum $\beta$-lactamase (ESBL) positive. Conclusion : Compared to prior reports from other tertiary hospitals in Korea, E. coli was the predominant cause in childhood UTI and the rate of ESBL positivity was low. The antibiotic resistance was also different compared to prior reports. We conclude that a difference in the cause and antibiotic resistance of childhood UTI exists between centers and this should be taken into consideration when prescribing antibiotics for childhood UTIs.

• Journal of Yeungnam Medical Science
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• v.28 no.2
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• pp.133-144
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• 2011

Background: Tigecycline (TIG), a new broad-spectrum glycylcycline with anti-multidrug-resistant-(MDR)-pathogen activity, was launched in March 2009 in South Korea, but there are insufficient clinical studies on its use in the country. As such, this study was performed to analyze cases of severe MDR-pathogen-caused infections treated with TIG. Methods: Patients treated with TIG within the period from May 2009 to June 2010 were enrolled in this study. Their clinical and microbiologic data were reviewed retrospectively. Results: Twenty-one patients were treated with TIG for complicated skin and soft-tissue infections (cSSTIs) (42.9%), complicated intra-abdominal infections (cIAIs) (38.1%), or pneumonia (19.1%) caused by MDR pathogens like carbapenem-resistant $Acinetobacter$ $baumannii$ (76.2%), methicillin-resistant $Staphylococcus$ $aureus$ (61.9%), extended-spectrum beta-lactamase-producing $Escherichia$ $coli$ and $Klebsiella$ $pneumoniae$ (38.1%), and penicillin-resistant $Enterococcus$ species (33.3%). Thirteen patients (61.9%) had successful clinical outcomes while five (23.8%) died within 30 days. The rate of clinical success was highest in cSSTI (77.8%), followed by cIAI (50%) and pneumonia (50%), and the mortality rate was highest in pneumonia (50%), followed by cIAI (25%) and cSSTI (11.1%), Conclusion: Tigecycline therapy can be an option for the treatment of severe MDR-pathogen-caused infections in South Korea, Due to its high risk of failure and mortality, however, prudence is required in its clinical use for the treatment of severe infections like nosocomial pneumonia.

• Microbiology and Biotechnology Letters
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• v.17 no.6
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• pp.600-605
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• 1989

For the purpose of isolation of the Zymomonas mobilis DNA fragments showing promoter activity in Escherichia coli, a promoter screening vector, PCMT215 was constructed by transferring a promoterless chloramphenicol acetyltransferase (CAT) gene of pYEJ001 into pMT21 which contains $\beta$-lactamase gene and multiple cloning sites. A library of Z, mobilis Sau3AI DNA fragments was constructed in E. coli using the newly constructed pCMT215. Fourteen clones showing resistance to chloramphenicol ranging in concentration from 30 to 750 $\mu$g/$m\ell$ were selected. From five clones of them, the Z. mobilis DNA fragments expressing CAT gene of the recombinant plasmids were sequenced and then sites of transcriptional initiation were identified. The nucleotide sequences of the cloned DNA shared AT rich regions, poly A's or T's stretches and palindromic regions. The positions of transcriptional initiation for CAT gene occurred at more than one site spaced over by 4 to 190 base pairs on the cloned fragments in E. coli.

• The Journal of the Korean Society for Microbiology
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• v.35 no.3
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• pp.263-271
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• 2000

A clinical isolate of Klebsiella pneumoniae K7746 produced the extended-spectrum ${\beta}$-lactamase (ESBL) SHV-12. A 6.6 kb BamHI fragment containing the $bla_{SHV-12}$ gene of K7746 strain was cloned into pCRScriptCAM vector resulting in the recombinant plasmid p7746-Cl. The restriction map of 3.6 kb inserted DNA and sequences immediately surrounding $bla_{SHV-12}$ of p7746-C1 were homologous to plasmid pMPA2a carrying $bla_{SHV-2a}$. In addition, both $bla_{SHV-12}$ and $bla_{SHV-2a}$ were expressed from a common hybrid promoter made of the -35 region derived from the left inverted repeat of IS26 and the -10 region from the $bla_{SHV}$ promoter itself. The results indicate that $bla_{SHV-12}$ and $bla_{SHV-2a}$ may have evolved from a common ancestor in the sequential order of $bla_{SHV-2a}$ first, followed by $bla_{SHV-12}$. Furthermore, by the PCR mapping method using primers corresponding to the IS26 and $bla_{SHV}$, the association between IS26 and $bla_{SHV}$ was studied in 12 clinical isolates carrying $bla_{SHV-2a}$, 27 clinical isolates carrying $bla_{SHV-12}$, and 5 reference strains carrying $bla_{SHV-1}$ to $bla_{SHV-5}$. All 39 strains carrying $bla_{SHV-2a}$ or $bla_{SHV-12}$ were positive by the PCR, providing confirmative evidence that IS26 has been involved in the evolution and dissemination of $bla_{SHV-2a}$ and $bla_{SHV-12}$. But 5 reference strains carrying $bla_{SHV-1}$ to $bla_{SHV-5}$ were negative by the PCR. Therefore, we concluded that the molecular evolutionary pathway of $bla_{SHV-2a}$ and $bla_{SHV-12}$ may be different from that of other $bla_{SHV-ESBL}$, e.g., $bla_{SHV-2}$, $bla_{SHV-3}$, $bla_{SHV-4}$, and $bla_{SHV-5}$.