• 한국식품위생안전성학회지
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• 제29권1호
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• pp.47-52
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• 2014

This study was performed to evaluate antimicrobial resistance of food-borne pathogens isolated from retail meat in Korea. A total of 157 samples of beef, pork, and chicken were collected and analyzed for E. coli, Salmonella, Campylobacter. Resistances to tetracycline were declined in accord with reduced usage of tetracycline in live stock production. E. coli stains from chicken meat had higher multi-drug resistance ratio than strains from other meat. One extended spectrum beta lactamase (ESBL) producing E. coli and two ESBL producing Salmonella were identified in this study. ESBL producing Salmonella strains were confirmed to carry CTX-M-1 type genes.

• Journal of Yeungnam Medical Science
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• 제35권1호
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• pp.84-88
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• 2018

A 33-year-old woman visited the emergency department presenting with fever and dyspnea. She was pregnant with gestational age of 31 weeks and 6 days. She had dysuria for 7 days, and fever and dyspnea for 1 day. The vital signs were as follows: blood pressure 110/70 mmHg, heart rate 118 beats/minute, respiratory rate 28/minute, body temperature $38.7^{\circ}C$, and oxygen saturation by pulse oximetry 84% during inhalation of 5 liters of oxygen by nasal prongs. Crackles were heard over both lung fields. There were no signs of uterine contractions. Chest X-ray and chest computed tomography scan showed multiple consolidations and air bronchograms in both lungs. According to urinalysis, there was pyuria and microscopic hematuria. She was diagnosed with community-acquired pneumonia and urinary tract infection (UTI) that progressed to severe sepsis and acute respiratory failure. We found extended-spectrum beta-lactamase producing Escherichia coli in the blood culture and methicillin-resistant Staphylococcus aureus in the sputum culture. The patient was transferred to the intensive care unit with administration of antibiotics and supplementation of high-flow oxygen. On hospital day 2, hypoxemia was aggravated. She underwent endotracheal intubation and mechanical ventilation. After 3 hours, fetal distress was suspected. Under 100% fraction of inspired oxygen, her oxygen partial pressure was 87 mmHg in the arterial blood. She developed acute kidney injury and thrombocytopenia. We diagnosed her with multi-organ failure due to severe sepsis. After an emergent cesarean section, pneumonia, UTI, and other organ failures gradually recovered. The patient and baby were discharged soon thereafter.

• 한국동물위생학회지
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• 제42권1호
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• pp.17-24
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• 2019

The aim of this study was to investigate the prevalence and characterization of plasmid-mediated quinolone resistance (PMQR) gene in 79 Enterobacteriaceae isolated from dogs and cats. Of 79 isolates, PMQR genes were found in 10 (12.7%) isolates, including aac(6')-lb-cr, qnrB, qnrS and qnrA detected alone or in combination in 8 (10.1%), 4 (5.1%), 2 (2.5%) and 1 (1.3%) isolates, respectively. Interestingly, two qnrS genes were detected in nalidixic acid and ciprofloxacin susceptible isolates. Extended-spectrum ${\beta}$-lactamase (ESBL) was detected in 90% (9 isolates) of PMQR positives isolates. Among ESBL genes, CTX-M, TEM and SHV were detected in 9, 8 and 3 isolates, respectively. Almost all PMQR genes were detected in co-existence with ESBL genes. All PMQR positives isolates were multidrug resistance (i.e. resistant to five or more antibiotics). qepA, OXA and CMY-2 genes were not found. The six transconjugants were obtained by conjugation experiment. The aac(6')-lb-cr, qnrB and qnrS were co-transferred with CTX-M, TEM and/or SHV, whereas qnrA was not observed among transconugants. This is the first report of the presence of aac(6')-lb-cr and qnrA gene among Enterobacteriaceae isolates from dogs in Korea. The prudent use of antimicrobials and continuous monitoring for companion animals are required.

• Childhood Kidney Diseases
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• 제23권1호
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• pp.29-35
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• 2019

Purpose: We aimed to determine characteristics of host, causative organisms, and antibiotic susceptibility of bacteria in pediatric patients with UTI living in metropolitan area of Korea. Methods: Retrospective investigation was done for the causative organisms of UTI in 683 pediatric cases treated at Ajou University Hospital from 2012 to 2017. Patients were classified into Escherichia coli and non-E. coli group, where E. coli group was subdivided into ESBL(+) and ESBL(-) groups based on whether the bacteria could produce extended spectrum beta-lactamase (ESBL). Antibiotic susceptibility of the causative organism was also determined. Results: A total of 683 UTIs occurred in 550 patients, of which 463 (67.8%) were first-time infection and 87 (32.2%) were recurrent ones (2-7 recurrences, 2.52 average), and 64.9% were male and 35.1% were female. The most common causative organism was E. coli (77.2%) and ESBL(+) E. coli was found in 126 cases. The susceptibility of E. coli to 3rd or 4th generation cephalosporin was relatively higher than that to ampicillin or amoxicillin/clavulanic acid. ESBL(+) E. coli showed higher resistance rate to 3rd or 4th generation cephalosporin than ESBL(-) E. coli. Conclusion: New treatment guideline should be considered due to the incidence of ESBL(+) E. coli increased up to one quarter of UTI cases.

• Clinical and Experimental Pediatrics
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• 제64권6호
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• pp.293-300
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• 2021

Background: Understanding the epidemiology and prevalence of febrile urinary tract infection (fUTI) in children is important for risk stratification and selecting appropriate urine sample collection candidates to aid in its diagnosis and treatment. Purpose: This study aimed to analyze the epidemiology, etiology, and changes in antibiotic susceptibility patterns of the first fUTI in children. Methods: This retrospective observational cohort study included children younger than 19 years of age who were diagnosed and treated for their first fUTI in 2006-2016. Electronic medical records were analyzed and radiologic images were evaluated. Results: A total of 359 patients (median age, 5.1 months; interquartile range, 3.0-10.5 months) fit the inclusion criteria; of them, 78.0% (n=280) were younger than 12 months old. The male to female ratio was 5.3:1 for patients aged 0-2 months, 2.1:1 for those 3-5 months, and 1.6:1 for those 6-11 months. Beyond 12 months of age, there was a female predominance. Escherichia coli was the leading cause (83.8%), followed by Enterococcus species (6.7%), and Klebsiella pneumoniae (3.6%). Significant yearly increases in the proportions of multidrug-resistant strains (P<0.001) and extended-spectrum beta-lactamase (ESBL) producers (P<0.001) were observed. In patients with vesicoureteral reflux (VUR), the overall recurrence rate was 53.6% (n=15). A significantly higher recurrence rate was observed when the fUTI was caused by an ESBL versus non-ESBL producer (75.0% vs. 30.0%, P=0.03). Conclusion: fUTI was most prevalent in children younger than 12 months of age and showed a female predominance in patients older than 12 months of age. The proportion of ESBL producers causing fUTI is increasing. Carbapenems, rather than noncarbapenems, should be considered for treating fUTI caused by ESBL-producing enteric gram-negative rods to reduce short-term recurrence rates in children with VUR.

• 한국융합학회논문지
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• 제6권5호
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• pp.77-84
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• 2015

본 연구는 항균제에 내성을 보이는 대장균의 특성을 알아보기 위해 설사환자에서 분리된 대장균에 대한 항균제 감수성 및 병원성 인자의 상관성을 분자융합적 기술을 통해 조사하였다. 분리한 대장균의 항균제 내성은 60주에서 ESBL(extendede spectrum ${\beta}$-lactamase) positive균주가 8주이고, negative균주는 52주였다. ESBL 양성 8주 중 2주는 병원성 유전자가 검출되지 않았으며, stb(3주), flich7(1주), flich7-eae(2주)로 나타났다. ESBL 음성 52주 중 26주는 병원성 유전자가 검출되지 않았고, stx1(3주), stb(10주), flich7 및 eae(각 2주), stx1-flich7(2주), stx1-stb(4주), flich7-stb(2주), flich7-stb-eae(1주)이었다. 결론적으로 항균제 내성이 증가하는 시대에 분자 융합적 관점에서 독력 유전자의 분포와 항균제 내성과의 관계는 적게 나타났으나, 향후 다양한 독력 유전자의 분석을 통한 융합기술연구가 이루어진다면 보다 정확한 병원성 인자를 추정할 수 있을 것으로 사료된다.

• Clinical and Experimental Pediatrics
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• 제49권8호
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• pp.882-888
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• 2006

목 적 : 소아 종양 환아 치료에서 감염은 사망까지 초래할 수 있어, 균혈증에 적절히 대처하는 것은 매우 중요하다. 이에 저자들은 현 시점에서 소아 암 환아에서 발생한 균혈증을 분석하여 앞으로의 치료에 참조하기 위해 이 연구를 시행하였다. 방 법 : 1998년 2월부터 2005년 5월 까지 계명대학교 동산의료원 소아과 병동에서 총 44명의 소아 종양 환아에서 발생되었던 62건의 균혈증을 후향적으로 분석하였다. 입원 당시 감염 소견이 있거나 입원 48시간 이내 발열이 있었던 환아들은 대상군에서 제외하였다. 결 과 : 그람양성균에 의한 균혈증은 30례, 그람음성균에 의한 균혈증은 24례, 진균혈증은 8례로 그람양성균의 빈도가 가장 높았다. 그람양성균 중에서는 Staphylococcus epidermidis 19례, Staphylococcus aureus 5례, alpha-hemolytic Streptococcus 5례의 순으로 빈도가 높았으며, 그람음성균에서는 Alcaligenes xylosoxidans 10례, Klebsiella pneumoniae 5례, Stenotrophomonas maltophilia 3례의 순으로 빈도가 높았다. 절대 호중구 수치가 $500/mm^3$ 이하인 경우는 모두 28례(45.2 %)였으며 그람양성균에서는 S. epidermidis가, 그람음성균에서는 K. pneumoniae가 가장 많았다. 항생제 감수성 검사를 시행하여서는 그람양성균 모두가 vancomycin과 teicoplanin에 감수성이 있었으나 methicillin에 내성을 보이는 경우가 S. epidermidis에서 61.5%(8/13), S. aureus에서 80%(4/5)이었다. 그람음성균에서의 감수성 결과, 대부분이 imipenem에 감수성을 보였다. K. pneumoniae는 모든 경우에서 extended-spectrum beta-lactamase(ESBL)가 양성이었고 K. pneumoniae에 감염된 환아 5례 중 4례가 패혈증과 관련되어 사망하였다. 결 론 : 본원에서도 다른 기관과 마찬가지로 균혈증의 원인으로 그람양성균이 많았다. 앞으로 주기적으로 균혈증의 원인균주를 분석하고 그 균주에 대한 항생제의 감수성을 참조하여 적절한 항생제를 선택할 수 있도록 하여야 할 것이다.

• 미생물학회지
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• 제40권4호
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• pp.286-294
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• 2004

1997년과 1998년 사이에 설사 증상을 보이는 돼지의 분변으로부터 총56균주의 Escherichia coli를 분리하여 이중 용혈성을 나타내는 38균주의 항생제 내성과 독소 생산능을 확인하였다. 항생제 한천 희석법으로 최소억제농도(minimal inhibitory concentration)를 측정한 결과 36균주$(94.7\%)$가 tetracycline에 대해 내성을 나타내었고, 27주$(71.0\%)$는 ampicillin에 내성, 26균주$(68.4\%)$는 chloramphenicol에 내성, 그리고 21균주$(55.2\%)$는 tri-methoprim에 내성을 나타내었으나, aztreonam, amikacin, norfloxacin에 내성을 나타낸 균주는 발견되지 않았다. 이중 4가지 이상의 항생제에 대해 내성을 가지는 다제내성(multiple drug resistance, MDR)을 보인 균주는 총 38 균주 중 21균주$(55.3\%)$였다. 또한 이중 디스크 시험법(Double Disk Synergy Test)을 수행한 결과 extended spectrum $\beta-lactamase$를 생산하는 균주는 없는 것으로 나타났다. 이들 중 가장 많은 수의 균주가 내열성 독소$(ST,89.5\%)$를 생산하였고, 다음으로 베로 독소(VT와 VTe, 각각$47.4\%$)와 이열성 독소$(LT,31.6\%)$를 생산하는 것으로 나타났다. 이 중에서 8균주$(21.0\%)$는 57만을 생산하였던 반면에 12균주$(31.6\%)$는 LT와 ST를 동시에 생산하였고, 13균주$(34.2\%)$는 ST, VT, VTe를 동시에 생산하였으며, 5균주$(13.2\%)$는 VT와 VTe를 동시에 생산하는 것으로 나타났다. 그러나 네 가지 독소를 동시에 생산하는 균주는 없었다. 또한 이 균주들은 매우 다양한 혈청형(serotype)을 가지고 있음이 확인되었다. 사람에 직접적인 유해성을 가지고 있는 지 확인하기 위해 사람 방광 유래의 T-24세포와 장내 표피 유래의 Caco-2세포에 대한 부착능을 시험하였을 때, 16균주$(42.1\%)$가 T-24방광 세포에, 그리고 17균주$(44.7\%)$가 Caco-2장세포에 대해 강한 부착능을 나타내었다. 특히 11균주$(28.9\%)$는 두 세포 모두에 강한 부착능을 가지고 있었다. Filter mating method를 수행하여 이들 균주들의 독소 생산 유전자와 항생제 내성 유전자가 사람에서 분리된 균주로 전달되는 것을 확인할 수 있었다. 본 실험의 결과는 설사 중상을 나타내는 돼지로부터 분리된 용혈성 E. coli의 독성과 세포 부착능력, 그리고 항생제 내성간의 상호 연관성을 보여주지 않았으나 동물 분리 세균의 항생제 내성과 독소 생산 능력이 유전자 전달을 통해서 뿐만 아니라 세균의 직접 접촉에 의해서도 인체로 전달될 수 있는 것을 보여주는 것이다.

• Journal of Yeungnam Medical Science
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• 제28권2호
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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.

• 대한미생물학회지
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• 제35권3호
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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 $bla_{SHV-5}$.