• Journal of Food Hygiene and Safety
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• v.29 no.1
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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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• v.35 no.1
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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.

• Korean Journal of Veterinary Service
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• v.42 no.1
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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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• v.23 no.1
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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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• v.64 no.6
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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.

• Urogenital Tract Infection
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• v.13 no.3
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• pp.72-78
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• 2018

Purpose: This retrospective study was undertaken to investigate whether increasing amikacin dosage for ciprofloxacin prophylaxis in patients with fluoroquinolone (FQ)-resistant rectal flora reduce infectious complications after transrectal ultrasound-guided prostate biopsy (TRUSPB). Materials and Methods: A total of 430 patients with FQ-resistant rectal flora based on rectal swab cultures were divided into two groups. Patients in both groups were administered ciprofloxacin (400 mg, intravenous [IV], twice daily) on the same day as TRUSPB and one day after biopsy. However, whereas group 1 patients (n=202) were administered a single injection of amikacin (1 g, IV) one hour before TRUSPB, patients in group 2 (n=228) were administered two injections of amikacin (1 g, IV) before one hour TRUSPB and again on the day after TRUSPB. Results: Of the 430 study subjects, 129 (30.0%) showed extended-spectrum beta-lactamase (ESBL) positivity. The overall incidence rate of infectious complications was 2.8% (12/430). Infectious complication rates were 4.0% (8/202) in group 1 and 1.3% (3/228) in group 2 (p=0.075). Urinary tract infection and acute prostatitis were more frequent in group 1 (3.5% vs. 0.4%, p=0.029). Infectious complication rates in ESBL negative patients were 3.4% (5/145) in group 1 and 1.3% (2/156) in group 2, whereas those in ESBL positive patients were 7.0% (4/57) in group 1 and 1.4% (1/72) in group 2. Conclusions: Increasing the dosage of amikacin for ciprofloxacin prophylaxis reduce infectious complications in patients with FQ-resistant rectal flora and to be more effective in ESBL positive patients with FQ-resistant rectal flora.

• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1672-1683
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• 2021

Vibrio parahaemolyticus is recognized as one of the most important foodborne pathogens responsible for gastroenteritis in humans. The bla_CARB-17 gene is an intrinsic β-lactamase gene and a novel species-specific genetic marker of V. parahaemolyticus. In this study, a loop-mediated isothermal amplification (LAMP) assay combined with a lateral flow dipstick (LFD) was developed targeting this bla_CARB-17 gene. The specificity of LAMP-LFD was ascertained by detecting V. parahaemolyticus ATCC 17802 and seven other non-V. parahaemolyticus strains. Finally, the practicability of LAMP-LFD was confirmed by detection with V. parahaemolyticus-contaminated samples and natural food samples. The results showed that the optimized reaction parameters of LAMP are as follows: 2.4 mmol/l Mg²⁺, 0.96 mmol/l dNTPs, 4.8 U Bst DNA polymerase, and an 8:1 ratio of inner primer to outer primer, at 63℃ for 40 min. The optimized reaction time of the LFD assay is 60 min. Cross-reactivity analysis with the seven non-V. parahaemolyticus strains showed that LAMP-LFD was exclusively specific for V. parahaemolyticus. The detection limit of LAMP-LFD for V. parahaemolyticus genomic DNA was 2.1 × 10^-4 ng/μl, corresponding to 630 fg/reaction and displaying a sensitivity that is 100-fold higher than that of conventional PCR. LAMP-LFD in a spiking study revealed a detection limit of approximately 6 CFU/ml, which was similar with conventional PCR. The developed LAMP-LFD specifically identified the 10 V. parahaemolyticus isolates from 30 seafood samples, suggesting that this LAMP-LFD may be a suitable diagnostic method for detecting V. parahaemolyticus in aquatic foods.

• Pediatric Infection and Vaccine
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• v.29 no.1
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• pp.46-53
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• 2022

It is challenging to treat ventriculitis with parenteral treatment alone in some cases because of the difficulty involved in maintaining an appropriate level of antibiotics in cerebrospinal fluid (CSF). We report two cases of ventriculitis who did not respond to intravenous (IV) antibiotics but were successfully treated with intraventricular antibiotics using IV agents. The first case was a four-month-old male patient with X-linked hydrocephalus. He showed ventriculitis due to Klebsiella pneumoniae not producing extended-spectrum β-lactamase and susceptible to third-generation cephalosporins and gentamicin, following ventriculoperitoneal (VP) shunt. His condition did not improve during the 47 days of treatment with IV cefotaxime and meropenem. We achieved improvement in clinical presentation and CSF profile after three times of intraventricular gentamicin injection. The patient was discharged from the hospital with antiepileptic drugs. The second case was a six-month-old female patient with a history of neonatal meningitis complicated with hydrocephalus at one month of age, VP shunt at two months of age, followed by a methicillin-resistant coagulase-negative staphylococci (CoNS) shunt infection with ventriculitis after the shunt operation. CoNS ventriculitis recurred four weeks later. We failed to treat intractable methicillin-resistant CoNS ventriculitis with IV vancomycin for ten days, and thus intraventricular antimicrobial treatment was considered. Five times of intraventricular vancomycin administration led to improvement in clinical parameters. There were only neurological sequelae of delayed language development but no other major complications. Patients in these two cases responded well to intraventricular antibiotics, with negative CSF culture results, and were successfully treated for ventriculitis without serious complications.

• Korean Journal of Veterinary Service
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• v.46 no.1
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• pp.35-45
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• 2023

Pathogenic Escherichia coli is the cause of a wide range of diseases in pigs, including diarrhea, edema disease, and septicemia. Diarrhea caused E. coli may result in significant economic losses, making pathogenic E. coli an important pathogen for the swine industry. This study investigated the prevalence of virulence factor genes, antimicrobial resistance phenotypes, and resistance genes in E. coli isolated from feces of piglets in Korea between 2017 and 2020. As a result, 119 pathogenic E. coli isolates were obtained from 601 fecal samples. The F4 adhesin gene and the STb enterotoxin gene were commonly present in E. coli isolated from diarrhea samples. The dominant virulotypes of isolates from diarrhea samples were STb, Stx2e, and F4:LT:STb. More than 80% of the screened isolates were resistant to ampicillin, sulfisoxazole, chloramphenicol, or tetracycline. To confirm the resistance mechanisms for β-lactam or quinolone, we investigated the genotypic factors of resistance. Each of the ceftiofur-resistant E. coli produced an extended-spectrum β-lactamase encoded by bla_CTX-M-14, bla_CTX-M-27, and bla_CTX-M-55. And all ciprofloxacin-resistant E. coli harbored mutations in quinoloneresistance-determining-regions. In addition, some of the ciprofloxacin-resistant E. coli contained the plasmid-mediated-quinolone-resistance genes such as qepA, qnrB1, or qnrD. This study has confirmed that the F4 fimbria and the STb enterotoxin are the most predominant in pathogenic E. coli isolated from piglets with diarrhea in Korea and there is a great need for responsible and prudent use of antimicrobials to treat colibacillosis.

• Journal of Veterinary Science
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• v.24 no.6
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• pp.82.1-82.12
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• 2023

Background: The current conventional serotyping based on antigen-antisera agglutination could not provide a better understanding of the potential pathogenicity of Salmonella enterica subsp. enterica serovar Brancaster. Surveillance data from Malaysian poultry farms indicated an increase in its presence over the years. Objective: This study aims to investigate the virulence determinants and antimicrobial resistance in S. Brancaster isolated from chickens in Malaysia. Methods: One hundred strains of archived S. Brancaster isolated from chicken cloacal swabs and raw chicken meat from 2017 to 2022 were studied. Two sets of multiplex polymerase chain reaction (PCR) were conducted to identify eight virulence genes associated with pathogenicity in Salmonella (invasion protein gene [invA], Salmonella invasion protein gene [sipB], Salmonella-induced filament gene [sifA], cytolethal-distending toxin B gene [cdtB], Salmonella iron transporter gene [sitC], Salmonella pathogenicity islands gene [spiA], Salmonella plasmid virulence gene [spvB], and inositol phosphate phosphatase gene [sopB]). Antimicrobial susceptibility assessment was conducted by disc diffusion method on nine selected antibiotics for the S. Brancaster isolates. S. Brancaster, with the phenotypic ACSSuT-resistance pattern (ampicillin, chloramphenicol, streptomycin, sulphonamides, and tetracycline), was subjected to PCR to detect the corresponding resistance gene(s). Results: Virulence genes detected in S. Brancaster in this study were invA, sitC, spiA, sipB, sopB, sifA, cdtB, and spvB. A total of 36 antibiogram patterns of S. Brancaster with a high level of multidrug resistance were observed, with ampicillin exhibiting the highest resistance. Over a third of the isolates displayed ACSSuT-resistance, and seven resistance genes (β-lactamase temoneira [bla_TEM], florfenicol/chloramphenicol resistance gene [floR], streptomycin resistance gene [strA], aminoglycoside nucleotidyltransferase gene [ant(3")-Ia], sulfonamides resistance gene [sul-1, sul-2], and tetracycline resistance gene [tetA]) were detected. Conclusion: Multidrug-resistant S. Brancaster from chickens harbored an array of virulence-associated genes similar to other clinically significant and invasive non-typhoidal Salmonella serovars, placing it as another significant foodborne zoonosis.