• Clinical and Experimental Pediatrics
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• v.52 no.7
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• pp.791-797
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• 2009

Purpose : We aimed to investigate the clinical manifestations of and antibiotic resistance in culture-proven childhood salmonellosis. Methods : Clinical manifestations and laboratory data of and antibiotic use in subjects with culture-proven childhood salmonellosis, who were treated at the Chonbuk National University Hospital between September 1998 and August 2008, were analyzed retrospectively. Patients with underlying diseases or concomitant illnesses were excluded. Results : We assessed a total of 72 patients. There were 68 stool culture-positive cases, 7 blood culture-positive cases, and 3 both stool culture- and blood culture-positive cases. Salmonella group D was the most frequent pathogen in stool (63.9%) and blood (71.4%) cultures. Salmonella typhi was isolated in 1 case. Of the 72 patients, 45 (62.5%) were male children, of which 29 (40.3%) were aged <3 years. The patients most commonly presented with diarrhea (90.2%) and fever (83.3%). Leukocytosis (leukocyte count, >$15,000/{\mu}L$) and leukopenia (leukocyte count, <$4,000/{\mu}L$) were detected in 8.3% and 5.6% of the patients, respectively. Elevated serum C-reactive protein concentration (>5 mg/dL) and erythrocyte sedimentation rate (>20 mm/h) were observed in 88.9% and 58.3% of the patients, respectively. Fifty-two (85.2%) of 61 patients who had undergone antibiotic treatment received a third-generation cephalosporin as definitive antibiotic therapy. Multidrug resistance rate was 40.0 % in the first 5 years of the study and 71.4% in the last 5 years. No fatalities occurred in this series. Conclusion : Children with culture-proven salmonellosis showed relatively benign clinical outcomes. Appropriate antibiotic treatment of <2 weeks is probably adequate for those without a suppurative focus of infection. The incidence of antibiotic resistant isolates was recently seen to increase.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.428-436
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• 2016

The emergence of antibiotic-resistant bacteria has been increased and become a public health concern worldwide. Many bacterial infections can be sequentially treated with different types of antibiotics. Thus, this study was designed to evaluate the changes in survival, antibiotic susceptibility, mutant frequency, ${\beta}$-lactamase activity, biofilm formation, and gene expression in Klebsiella pneumoniae after exposure to sequential antibiotic treatments of ciprofloxacin and meropenem. Treatments include control (CON; no addition), 1/2 MIC ciprofloxacin addition (1/2CIP), 2 MIC ciprofloxacin addition (2CIP), initial 1/2 MIC ciprofloxacin addition followed by 1/2 MIC meropenem (8 h-incubation) and 2 MIC ciprofloxacin (16 h-incubation) (1/2CIP-1/2MER-2CIP), initial 1/2 MIC ciprofloxacin addition followed by 1/2 MIC meropenem (8 h-incubation) and 2 MIC meropenem (16 h-incubation) (1/2CIP-1/2MER-2MER), and initial 1/2 MIC ciprofloxacin addition followed by 2 MIC ciprofloxacin(8 h-incubation) and 2 MIC meropenem(16 h-incubation) (1/2CIP-2CIP-2MER). No growth of K. pneumoniae was observed for the 2CIP throughout the incubation period. The numbers of planktonic cells varied with the treatments (7~10 log CFU/ml), while those of biofilm cells were not significantly different among treatments after 24-h incubation, showing approximately 7 log CFU/ml. Among the sequential treatments, the least mutant frequency was observed at the 1/2CIP-1/2MER-2CIP (14%). Compared to the CON, 1/2CIP-2CIP-2MER decreased the sensitivity of K. pneumoniae to piperacillin, cefotaxime, and nalidixic acid. The highest ${\beta}$-lactamase activity was 22 nmol/min/ml for 1/2CIP-1/2MER-2CIP, while the least ${\beta}$-lactamase activity was 6 nmol/min/ml for 1/2CIP-2CIP-2MER. The relative expression levels of multidrug efflux pump-related genes (acrA, acrB, and ramA) were increased more than 2-fold in K. pneumoniae exposed to 1/2CIP-1/2MER-2MER and 1/2CIP-2CIP-2MER. The results suggest that the sequential antibiotic treatments could change the antibiotic resistance profiles in K. pneumoniae.

• Childhood Kidney Diseases
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• v.9 no.1
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• pp.46-55
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• 2005

Purpose : Recurrent urinary tract Infection(UTI) in primary vesicoureteral reflux(VUR) may lead to serious renal scarring, a major cause of childhood hypertension and end-stage renal disease. To prevent recurrent UTI, low-dose long--term antibiotic prophylaxis has been recommended. However, recurrent UTI still develops during antibiotic prophylaxis, the efficacy of which is now being disputed. The emergence of resistant bacteria has also raised concerns. To evaluate the effect of antibiotic prophylaxis, we investigated recurrent UTI during prophylactic antibiotic use in children with primary VUR Materials : The incidence and risk factors of recurrent UTI were retrospectively evaluated in ninety-one children with primary VUR on trimethoprim- sulfamethoxazole(TMP/SMX) prophylafis during the year following their index febri]e UTI. Results : Recurrent UTI occurred in 31.9%(29/91) children and comprised 0.32 episodes/patient year. Febrile UTI was 0.26 episode/patient year and afebrile UTI was 0.07 episodes/patient year. The recurrent rate of UTI in male patients with phimosis was 37.2%(19/51), which was significantly higher than in males without phimosis 0%(0/5)(P=0.025). In the logistic regression analysis for recurrent UTI, renal scar was the significant risk factor for recurrent UTI [RR 3.8(95% CI 1.0-14.1) P=0.04]. For other well-known risk factors such as sex, age, degree of VUR, APN, and voiding dysfunction, the differences were not significant. Conclusion : TMP/SMX prophylaxis did not prevent recurrent UTI in children with primary VUR. Phimosis and renal scars were the risk factors for recurrent UTI but the grade of primary VUR was not. In VUR without phlmosis and renal scar, a randomized controlled study without antibiotic prophylaxis is required. (J Korean Soc Pediatr Nephrol 2005;9:46-55)

• 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 Food Hygiene and Safety
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• v.17 no.2
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• pp.71-78
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• 2002

With the incidence of antibiotic resistant bacteria there is increasing interest in natural products such as herb extract and probiotics to control antibiotic resistant bacteria. This study was focused on the determination of antimicrobial activity of Opuntia ficus-indica var. saboten against Salmonella enetrica serovar Enteritidis (S. enterifidis), S. enterica serovar Typhimurium (S. Typhimurium) DT 104 and Escherichia coli 0157:H7. Though bactericidal effect of 0. ficus-indica var. saboten was not observed, it had significant inhibitory activity against Salmonella spp. and E. coli O157:H7 on the Moulter Hinton agar containing its solution dissolved in deionized water. To investigate the antimicrobial activity in vivo, mice were challenged with 5. Typhimurium DT104 (3.7$\times$108 cfu/mouse) after pre-feeding 0. ficus-indica var. saboten solution. The fecal shedding of S. Typhimurium DT104 was more dramatically decreased and not detectable in feces and intestines 3 days after challenge in mice fed with 0. ficus-indica var. saboten. Antibody responses of the intestinal IgA were also significantly increased in mice fed with 0. ficus-indica var. saboten. These findings suggest that Opuntia ficus-indica var. saboten decreased the shedding of S. Typhimurium DT104 in vitro and also in the gastrointestinal tract in mice. In addition, administration of the product might enhance the mucosal immune response against S. Typhimurium DT 104. In conclusion, Opuntia ficus-indica var. saboten might be useful to control antibiotic resistant bacteria in vivo and in vitro.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.3
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• pp.402-413
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• 2001

Food safety is a term broadly applied to food quality that may adversely affect human health. These include zoonotic diseases and acute and chronic effects of ingesting natural and human-made xenobiotics. There are two major areas of concern over the presence of residues of antibiotics in animal-derived foodstuffs with regard to human health. The first is allergic reactions. Some antibiotics, such as penicillins can evoke allergic reactions even though small amounts of them are ingested or exposed by parenteral routes. The second is development of antibiotic resistance in gut bacteria of human. Recently multi-resistant pneumococcal, glycopeptide-resistant enterococci and gram negative bacteria with extended-spectrum $\beta$-lactamases have spread all over the world, and are now a serious therapeutic problem in human. Although it is evident that drugs are required in the efficient production of meat, milk and eggs, their indiscriminate use should never be substituted for hygienic management of farm. Drug should be used only when they are required. In addition to veterinary drugs, environmental contaminants that were contaminated in feed, water and air can make residues in animal products. Mycotoxins, heavy metals, pesticides, herbicides and other chemicals derived from industries can be harmful both to animal and human health. Most of organic contaminants, such as dioxin, PCBs and DDT, and metals are persistent in environment and biological organisms and can be accumulated in fat and hard tissues. Some of them are suspected to have endocrine disrupting, carcinogenic, teratogenic, immunodepressive and nervous effects. The governmental agencies concerned make efforts to prevent residue problems; approval of drugs including withdrawal times of each preparation of drugs, establishment of tolerances, guidelines regarding drug use and sanitation enforcement of livestock products. National residue program is conducted to audit the status of the chemical residues in foods. Recently HACCP has been introduced to promote food safety from farm to table by reducing hazardous biological, chemical and physical factors. Animal Production Food Safety Program, Quality Assurance Programs, Food Animal Residue Avoidance Databank are para- or non-governmental activities ensuring food safety. This topic will cover classification and usage or sources of chemical residues, their adverse effects, and chemical residue status of some countries. Issues are expanded to residue detection methodologies, toxicological and pharmacokinetic backgrounds of MRL and withdrawal time establishments, and the importance of non-governmental activities with regard to reducing chemical residues in food.

• Pediatric Infection and Vaccine
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• v.26 no.3
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• pp.140-147
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• 2019

Purpose: Staphylococcus aureus is a major cause of skin and soft tissue infections (SSTIs). This study aimed to determine the temporal trends in antibiotic susceptibility of S. aureus in SSTI patients aged <19 years. Methods: This retrospective observational study was conducted in pediatric patients with SSTI caused by community-associated S. aureus. Microbiologic and demographic data were collected, and the trends of antibiotic susceptibility results were evaluated. Results: From January 2010 to December 2018, a total of 807 S. aureus isolates were included. An overall increase in susceptibility of isolates to oxacillin was noted (P<0.001), with 75.0% of isolates being oxacillin-susceptible in 2018. S. aureus remained highly susceptible to trimethoprim/sulfamethoxazole and tetracycline, with 97.6% and 95.2% isolate susceptibility in 2018, respectively. Isolates from younger children aged 1 to 5 years had a significantly lower rate of susceptibility to oxacillin than older children aged 6 to 18 years (53.4% vs. 75.0%, P<0.001). Conclusions: The proportion of methicillin-resistant S. aureus isolates appears to decrease in pediatric patients with community-associated SSTI caused by S. aureus. Clinicians should be aware of regional susceptibility patterns when choosing empirical regimens.

• Journal of Embryo Transfer
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• v.25 no.4
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• pp.267-272
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• 2010

The present study was to investigate the source of contamination during semen processing for in vitro uses. In the present study, frozen semen was prepared from liquid semen in our laboratory for in vitro fertilization (IVF) experiments due to lack of fresh semen. Antibiotics were added in the frozen semen extender (kanamycin and gentamicin) and in vitro culture (IVC) medium (gentamicin) for further inhibiting growth of microorganisms. Nevertheless, proliferations of microorganisms were observed in IVC culture drop during culturing of IVF embryos using frozen semen. Randomly 3 samples were taken from the liquid semen, frozen semen and egg yolk. Contaminated IVC medium, frozen-thawed semen, liquid semen and egg yolk were cultured in de Man, Rogosa and Sharpe (MRS) agar medium. Whitish colonies were detected in contaminated IVC drop, frozen-thawed semen samples and egg yolk but no colonies were formed in liquid semen samples. Gram-negative and rod-shaped identical bacteria were found in both frozen-thawed semen sample and contaminated IVC drop and egg yolk samples. Enterobacter cloacae were confirmed by API 20E kit according to manufacturer's instruction with identification value (% ID) 94.3% and T index 0.88. Antibiotic susceptibility tests were done according to Clinical and Laboratory Standards Institute (CLSI) by using ampicillin, amikacin, cephalothin, gentamicin, kanamycin, tetracycline, oxytetracycline, sulfamethoxazole trimethoprim, norfloxacin and ciprofloxacin test. Among them Enterobacter cloacae were resistant to ampicillin, amikacin, cephalothin, gentamicin, kanamycin but susceptible to tetracycline, oxytetracycline, sulfamethoxazole trimethoprim, norfloxacin and ciprofloxacin. From these findings it could be suggested that this contamination sources might be from egg yolk.

• Food Science of Animal Resources
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• v.36 no.6
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• pp.779-786
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• 2016

This study aimed to evaluate the prevalence of Listeria monocytogenes on livestock farms in Korea and determine their serotypes and genetic correlations. Twenty-five livestock farms in Korea (central: 15, south west: 7, south east: 3) were visited 2-3 times, and 2,018 samples (feces: 677, soil: 680, silage: 647, sludge: 14) were collected. Samples were enriched in LEB (Listeria enrichment broth) and Fraser broth media, and then plated on Palcam agar. The isolates were identified by PCR and 16S rRNA gene sequencing. Then, the sero-types, presence of virulence genes (actA, inlA, inlB, plcB, and hlyA), and antibiotic resistance were determined. Genetic correlations among the isolates were evaluated by analyzing the restriction digest pattern with AscI. Of the 2,018 samples, only 3 (0.15%) soil samples (FI-1-FI-3) from 1 farm in the south east region were positive for L. monocytogenes. Based on biochemical tests and multiplex PCR, the serotype of the isolates were 4ab (FI-1 and FI-3) and 3a (FI-2), which are not common in foodborne L. monocytogenes. The 3a sero-type isolate was positive for all tested virulence genes, whereas the 4ab serotype isolates were only positive for hlyA, actA, and inlA. The isolates were resistant to all 12 tested antibiotics, especially FI-3. The genetic correlations among the isolates were 100% for those of the same serotype and 26.3% for those of different serotypes. These results indicate that the prevalence of L. monocytogenes on livestock farms in Korea is low; however, the isolates are pathogenic and antibiotic resistant.

• Journal of Life Science
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• v.15 no.4 s.71
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• pp.647-651
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• 2005

The major causative bacteria of food poisoning were Salmonella spp. $(35.6\%)$, Staphylococcus aureus $(11.3\%)$ and Vibrio parahaemolyticus $(3.2\%)$ in our country. In this study we attempted isolation of S. aureus from stools of patients with diarrhea. Sixty-four strains $(9.1\%)$ were isolated from 704 the stools of patients with diarrhea. The enterotoxin was detected from 29 isolates $(45.3\%)$: 24 isolates $(37.5\%)$, 3 isolates $(4.7\%)$ and 2 isolates $(3.1\%)$ were A, B and C type, respectively. In the antibiotic susceptibility, 63 isolates $(98.4\%)$ were resistant to penicillin, 60 isolates $(93.8\%)$ to ampicillin, 35 isolates $(54.7\%)$ to erythromycin, 32 isolates $(50.0\%)$ to gentamycin, 22 isolates $(34.4\%)$ to tetracycline and 20 isolates $(31.3\%)$ to oxacillin. All of S. aureus isolates were susceptible to chloramphenicol and vancomycin, 20 isolates $(31.3\%)$ were methicillin-resistance S. aureus (MRSA). MRSA isolation rate was higher in male $(35.7\%)$ than female $(26.3\%)$. With the exception of two isolates which were resistant only to penicillin, sixty-one isolates were multiple antibiotic resistance.