• 한국동물위생학회지
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• 제34권1호
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• pp.37-43
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• 2011

This study was conducted to investigate the prevalence and genotypes of extended-spectrum ${\beta}$-lactamase (ESBL) in 377 Escherichia coli isolated from healthy and sick animals. Two isolates (0.5%), each of which were isolated from diseased swine and chicken, respectively, were confirmed as ESBL producing isolates by double disk synergy test, and showed a multidrug resistant phenotype. Minimum inhibitory concentration of cefotaxime for the two ESBL producing isolates were 3~4 times higher than those of ceftazidime, respectively. By PCR and sequencing, one isolate from swine have both $bla_{CTX-15}$ and $bla_{TEM-1}$, and one isolate from chicken have $bla_{CTX-15}$ and $bla_{TEM-116}$. Also, these genes were transferred to E. coli J53 by conjugation. These two isolates showed unrelated pulsed-field gel electrophoresis. To our knowledge, this is the first time that $bla_{TEM-116}$ gene was identified in E. coli isolated from animals in Korea. These results suggest more prudent use of third- generation cephalosporins, and surveillance and monitoring for ESBL producing E. coli in both animals and their environments should be necessary.

• Journal of Veterinary Science
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• 제23권3호
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• pp.37.1-37.8
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• 2022

Background: Avian pathogenic Escherichia coli (APEC) causes colibacillosis, resulting in significant economic losses in the poultry industry. Objectives: In this study, the molecular characteristics of two extended-spectrum beta-lactamase (ESBL)-producing APEC isolates were compared with previously reported ESBL-producing E. coli isolates. Methods: The molecular characteristics of E. coli isolates and the genetic environments of the ESBL genes were investigated using whole genome sequencing. Results: The two ESBL-producing APEC were classified into the phylogenetic groups C and B1 and ST410 and ST162, respectively. Moreover, the ESBL genes of the two isolates were harbored in different Inc plasmids. The EC1809182 strain, harboring the bla_CTX-M-55 gene on the plasmid, exhibited extensive homology to IncFIB (98.4%) and IncFIC(FII) (95.8%). The EC1809191 strain, harboring the bla_CTX-M-1 gene, was homologous to IncI1-I (Gamma) (99.3%). All chromosomes carried the multidrug transporter, mdf(A) gene. Mobile genetic elements, adjacent to CTX-M genes, facilitated the dissemination of genes in the two isolates, analogous to other ESBL-producing E. coli isolates. Conclusions: This study clarifies the transmission dynamics of CTX-M genes and supports strengthened surveillance to prevent the transmission of the antimicrobial-resistant genes to humans via the food chain.

• 디지털융복합연구
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• 제14권10호
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• pp.349-354
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• 2016

다양한 extended-spectrum ${\beta}$-lactamase (ESBL)를 생성하는 폐렴막대균의 출현 및 확산은 세균에 의한 감염증 치료에 어려움을 가중시키고 있다. 본 연구에서는 충청지역에서 분리된 폐렴막대균을 대상으로 ESBL 유전자를 검출하고 항균제 감수성 양상을 조사하였다. 또한 같은 클론에서 유래하였는지를 확인하기 위해 repetitive element sequence-based (REP)-PCR을 수행하였다. 충청지역에서 분리된 폐렴막대균 102균주 중 21균주가 CTX-M-14 및/또는 CTX-M-15를 생성하는 것으로 나타났으며 이 균주들은 3세대 cephalosporin 계열 항균제에 대해 70% 이상의 높은 내성율을 보였다. 본 연구에서 분리된 CTX-M형 ESBL생성 폐렴막대균은 다양한 클론으로부터 유래되었으며 그 중 일부는 지역사회에 확산되어 있음이 확인되었다. 이러한 폐렴막대균의 감염 및 확산을 방지하기 위해서는 감염관리의 강화가 필요하다. 아울러 좀 더 효과적인 내성세균의 관리를 위해서는 내성유전자의 생물학적 조사와 통계학적 분석을 통해 통합적으로 구축된 데이터베이스를 모니터링 할 필요가 있을 것으로 사료된다.

• Childhood Kidney Diseases
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• 제10권2호
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• pp.182-191
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• 2006

Purpose : We studied the degree of changes in antibiotic sensitivity toward causative organisms, prevalence and clinical manifestations of extended-spectrum $\beta$-lactamase(ESBL)-producers of urinary tract infection(UTI) for a period of three years. This serves to provide useful information in selecting adequate drugs for the treatment of UTI. Methods : We recruited 137 patients who grew more than $10^5$ CFU/mL in their urine culture among 250 patients who visited and were admitted to Handong University's Sunlin Hospital for UTI treatment from January 2003 to December 2005. We retrospectively analyzed the data from the medical records. Results : The common pathogenic organisms were Escherichia coli(65.0%), Klepsiella pneumoniae(14.0%), Enterococcus faecalis(5.8%) and Proteus vulgaris(2.9%) in consecutive order. The prevalence of ESBL-producers among isolated E. coli and K. pneumoniae was 4.5%(4 cases) and 14.3%(2 cases), respectively. The antibiotic sensitivity rates of E. coli were relatively high to amikacin(100%), imipenem(100%), ceftriaxone(95.5%) and tobramycin(91.4%) while relatively low to TMP/SMZ(55.4%), ampicillin/sulbactam(29.4%) and ampicillin(24.2%). Conclusion : The use of ampicillin, ampicillin/sulbactam and TMP/SMZ, which have been the first choices in the treatment of UTI, should be reconsidered due to the low sensitivity rates towards these antibiotics. Due to the high incidence and antibiotic tolerance of ESBL that might have risen from the development of new antibiotics and increased antibiotic use, it is necessary to consider changing the standard antibiotics that have been used in the treatment of UTI.

• Journal of Microbiology and Biotechnology
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• 제16권6호
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• pp.889-895
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• 2006

To investigate the antibiotic-resistant patterns and the gene types of extended-spectrum $\beta$-lactamase (ESBL)-producing Klebsiella pneumoniae, we collected 226 Klebsiella pneumoniae strains from three general hospitals with more than 500 beds in Busan, Korea from September 2004 to October 2005, The minimum inhibitory concentration (MIC) of antibiotics was measured using the Gram-negative susceptibility (GNS) cards of Vitek (Vitek system, Hazelwood Inc., MO, U.S.A.). Of the 226 K, pneumoniae isolates, 65 ESBL-producing K. pneumoniae strains were detected by the Vitek system and confirmed by the double-disk synergy test. TEM (Temoniera) type, SHV (sulfhydryl variable) type, and CTX-M (cefotaxime) type genes were detected by polymerase chain reaction. All 65 K. pneumoniae strains were resistant to ampicillin, cefazolin, cefepime, ceftriaxone, and aztreonam, and 83.0% of the organisms were resistant to ampicillin/sulbactam, 66.1% to tobramycin, 67.6% to piperacillin/tazobactam, 61.5% to ciprofloxacin, and 47.6% to trimethoprim/sulfamethoxazole, and 43.0% to gentamicin. TEM-type ESBLs (TEM-1 type, -52 type) were found in 64.6% (42 of 65) of the isolates, SHV-type ESBLs (SHV-2a type, -12 type, -28 type) in 70.7% (46 of 65) of isolates, and CTX-M-type ESBLS (CTX-M-15 type) in 45% (29 of 65) of isolates. Of the 65 ESBL-producing K. pneumoniae strains, two strains were found to harbor blaSHV-28, which were detected in Korea for the first time. Therefore, more investigation and research on SHV-28 are needed in order to prevent the ESBL type-producing K. pneumoniae from spreading resistance to oxyimino cephalosporin antibiotics.

• 고신대학교 의과대학 학술지
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• 제33권2호
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• pp.159-170
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• 2018

Objectives: The purpose of this study was to compare antibiotic resistance patterns between first urinary tract infection (UTI) and recurrent UTI groups and to obtain information regarding empirical antibiotic selection for treating recurrent UTI. Methods: We retrospectively reviewed 148 children treated for UTIs from January 2009 to June 2016. The patients were divided into two groups: first UTI (N = 148) and recurrent UTI (17 patients and 20 episodes). Results: In both groups, Escherichia coli was the most frequent causative organism, accounting for 89.9% and 75.0% in the first and recurrent UTI groups, respectively. When E. coli or Klebsiella pneumoniae was the causative organism, extended-spectrum ${\beta}-lactamase$ (ESBL)-producing organisms were more frequent in the recurrent UTI group (17.6%) than in the first UTI group (14.0%); however, this difference was not statistically significant (P = 0.684). Cefotaxime was the most frequently used first-line empirical antibiotic in both groups. In the first UTI and recurrent UTI groups, 7.4% and 15.0% of patients were treated with intravenous antibiotics as definitive therapy, respectively (P = 0.250). Fifteen out of 17 patients having a second UTI had different causative organisms or antibiotic susceptibility patterns compared to their previous episode. Conclusions: Escherichia coli was the most frequent causative organism in the recurrent UTI group. There were no differences in the proportion of ESBL-producing organisms between the first UTI and recurrent UTI groups. Therefore, when a UTI recurs in children, the antibiotics effective on the most common causative organism might be administered as empirical antibiotics.

• Childhood Kidney Diseases
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• 제23권1호
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• pp.22-28
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• 2019

Purpose: We studied the pathogens and trends in antibiotic sensitivity pattern in children with urinary tract infection (UTI) over 8 years in order to evaluate adequate treatment. Methods: We performed a retrospective review of medical records of children with UTI from January 2009 to December 2016 in Daegu Fatima Hospital. Uropathogens and antibiotic sensitivity patterns were selected. Only 1 bacterial species with a colony count of ${\geq}105CFU/mL$ was considered a positive result. We compared 2 periods group (A: 2009~2012, B: 2013~2016) to investigate trends of antibiotic sensitivity pattern. Results: During the 8 year period, 589 cases are identified (E. coli was cultured in 509 cases, 86.4%). Among all patients, this study investigated the antibiotic sensitivity of E. coli. Antimicrobial susceptibility to ampicillin was steadily low for both periods (A: 32.6%, B: 40.1%, P=0.125), and to amikacin was consistently high for both periods (A: 99.4%, B: 99.3%, P=1.000). Antibiotic sensitivity to third-generation cephalosporin decreased from period A to B (A: 91.7%, B: 75.5%, P=0.000). Antibiotic sensitivity to quinolone significantly decreased from A to B (A: 88.4%, B: 78.2%, P=0.003). The prevalence of extended-spectrum ${\beta}$-lactamase-producing E. coli increased from period A to B (A: 6.1%, B: 17.1%, P=0.000). Conclusion: This study showed that conventional antibiotic therapy for the treatment of pediatric UTI needs to be reevaluated. A careful choice of antibiotic is required due to the change in antibiotic sensitivity and the emergence of antibiotic-resistant bacteria.

• Neonatal Medicine
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• 제18권2호
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• pp.265-271
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• 2011

목적: ESBL 생성 균주는 1990년대 접어들어 신생아 중환자실에서 중요한 감염증 원인균 중하나로 대두되었다. 본 연구에서는 ESBL 생성하는 E. coli 및 K. pneumoniae에 감염된 신생아들과 ESBL 음성인 E. coli 및 K. pneumoniae에 감염된 신생아들에 있어서 임상적인 특징 및 혈액학적 검사 소견 등의 차이점을 알아보고자 본 연구를 시행하였다. 방법: 2005년 1월부터 2010년 9월까지 인제대학교 상계백병원 신생아 중환자실에 입원 한 환아 중 배양 검사에서 E. coli 또는 K. pneumoniae가 분리된 48명, 55균주를 대상으로 ESBL 생성 여부에 따라서 두 군으로 구분하여 임상적 특징 및 혈액학적 검사 소견을 의무기록을 토대로 조사하여 두 군간 비교를 시행하였다. 결과: 배양 검사에서 ESBL 양성은 총 18명 20균주였고, ESBL 음성은 총 30명 35균주 였다. ESBL 생성 20균주 중 E. coli 가 13균주, K. pneumoniae가 7균주 였다. ESBL 양성 균주와 ESBL 음성 균주 소변배양 검사에서 각각 10균주 및 23균주로 가장 많이 검출되었다. 1분 및 5분 Apgar 점수는 ESBL 양성 환아군에서 통계학적으로 유의하게 더 낮았고(P=0.002, P=0.001). 산소 공급 필요성은 ESBL 양성 환아군에서 더 많았고(56% vs. 27%;P=0.005), 산소 공급 일수도 ESBL 양성 환아군에서 더 길었다(15.8${\pm}$38.43일 vs. 4.3${\pm}$12.5일; P=0.008). 배양 검사 양성 시점의 발열, 무호흡, 산모력, 성별, 재태 연령, 출생 체중에서는 두 군간 유의한 차이는 없었다. 혈액학적 검사에서 배양 검사 양성 시점 빈혈은 ESBL 양성 환아군에서 더 많았으나(33% vs. 7%;P=0.040) 혈색소, 백혈구수, 혈소판수 및CRP는 유의한 차이를 보이지 않았다. 결론: ESBL 양성 환아군이 음성인 환아군에 비해 Apgar 점수가 낮았고 상대적으로 빈혈이 더 빈번하였다. 출생 시에 낮은 Apgar 점수를 보이는 환아들 중에서 기존 항생제를 사용 중인 환아에서 감염증의 새로운 증상이 보이거나 환아의 상태가 악화되는 경우에는 조기에 carbapenem 항생제를 사용하는 것을 고려할 수 있을 것으로 생각된다.

• Clinical and Experimental Pediatrics
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• 제49권2호
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• pp.150-156
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• 2006

목 적 : 2000년 6월과 7월에 본원 신생아 중환자실에서는 ESBL 생성 K. pneumoniae에 의한 패혈증이 집단 발생하여 전체 환아에 대한 보균 상태를 파악하고 감염관리를 위해 감시배양을 실시하였다. 당시 집단 보균 상태임을 발견하여 보균자에 대한 격리를 실시한 결과 집단보균을 해결할 수 있었으나 대부분의 환아가 보균 상태로 퇴원하였다. ESBL 생성 K. pneumoniae는 대변 내 균이 장착되어서 입원 환아들간에 집단 감염을 일으킬 수 있으며, 이러한 균주에 의한 집단감염은 치료와 예후에 중요한 인자로 작용될 것으로 생각된다. 이에 저자들은 집단보균 발생시 분리된 ESBL 생성 K. pneumoniae의 분자 역학적 특징과 보균환아들의 추적관찰 결과를 알아보고자 본 연구를 시행하였다. 방 법 : 2000년 7월 28일부터 12월 30일까지 입원환아를 대상으로 직장내 도말법으로 감시배양검사를 시행하였다. 감시배양검사는 재원환아들에서 1주 간격으로 시행하였고, 신환은 입원 당일에 시행하였다. 균주의 형별 검사를 위해서 Pulsed-field gel electrophoresis(PFGE)를 시행하였고, 보균 상태로 퇴원했던 환아들은 외래에서 대변 배양검사로 추적 관찰하였다. 결 과 : 감시 배양기간 중 총 80명(28.5%)의 환아에서 보균이 확인되었고, 퇴원시 5명(6.3%)에서 음성이 확인되었다. PFGE를 시행한 65명의 타이핑 결과, 일회의 PFGE를 시행한 53명에서 분리된 균주의 염색체 유전자 분획양상은 집단클론 6가지, 단독클론 10가지형으로 분류되었고, 집단 클론 중 A형이 28명(52.8%)으로 가장 많았고, B형이 11명(20.8%), C, D, F, G형이 각각 1명(1.9%)이었다. 2회 이상 검사를 시행한 12명 중 초기검사에서는 A형이 10명(83.3%)으로 월등히 많았고 B형은 2명(16.7%)이었으며, 추적검사에서 분획 양상이 변화된 경우는 6명(50%)이었고, 이들은 A나 B로 변화된 경우가 각각 2명(33.3%)이었다. 변화되지 않은 6명(50%)은 모두 A형으로 남아 있었다. 월별 PFGE 양상은 처음 배양시 집단클론 A, B, C, D형 4가지와 단독클론 세 가지형이었으나 감염 관리를 하면서 11월부터 집단클론 A, B 두 가지형으로 나타나는 양상을 보였고, A형이 더 우세하였다. 보균된 상태로 퇴원한 75명 중 외래 추적관찰이 가능했던 30명을 대상으로 대변 배양검사를 시행한 결과 모두 음성이 확인되었다. 결 론 : 다양한 클론의 균주에 의한 집단보균 상태는 감염 관리를 하면서 단일 클론으로 변화하는 양상을 보였고, A형이 우세한 것으로 보아 집단 보균을 일으킨 유형 중 주 집단 클론은 A형이었음을 알 수 있었다. ESBL 생성 K. pneumoniae 보균 상태는 중환자실내에 입원기간 중에는 거의 지속되지만, 지역사회로 복귀하면 전부 해제되는 것으로 보인다.

• 대한의생명과학회지
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• 제18권3호
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• pp.299-306
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• 2012

Recently, the prevalence of 16S rRNA methylase conferring high-level resistance to aminoglycosides has been increasing in Gram-negative bacilli globally. We determined the prevalence and genotype of these methylase-producing bacteria, and characterized the co-resistance to ${\beta}$-lactam antibiotics and quinolone in Gram-negative clinical isolates collected in 2010 at a hospital in Korea. Among 65 amikacin-resistant isolates screened from 864 Gram-negative bacilli (GNB), 16S rRNA methylase genes were detected from 49 isolates, including Acinetobacter baumannii (43), Klebsiella pneumoniae (2), Proteus mirabilis (2) and Serratia marcescens (1), Empedobacter brevis (1). All of the 16S rRNA methylase genotype was armA and no variant sequences of amplified PCR products for armA were noted. The 16S rRNA methylase producing bacteria showed much higher resistance to aminoglycoside for Enterobacteriaceae and glucose non-fermenting (NF)-GNB and to imipenem for glucose NF-GNB, than the non-producing isolates. All of the 16S rRNA methylase producing Enterobacteriaceae had the extended-spectrum-${\beta}$-lactamase. In addition, two K. pneumoniae concurrently produced both plasmid-mediated AmpC ${\beta}$-lactamase and qnrB gene. All of the amikacin-resistant A. baumannii (43) co-harbored armA 16S rRNA methylase and $bla_{OXA-23}$ carbapenemase. In conclusion, 16S rRNA methylase producing bacteria were very prevalent among GNB in South Korea, and were commonly associated with co-resistance, including carbapenem and quinolone.