• 대한수의학회지
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• 제34권3호
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• pp.501-510
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• 1994

This paper deals with the distribution, reservoir and mode of spread of infection on 6 hatcheries in Taegu, Kyungpook and 5 broiler farms in Kyungpook during the period from June 1991 to June 1992. Isolated Salmonella were examined for serotypes, biotyping of Salmonella(S) typhimurtum, antibiotic susceptibility and some biochemical characteristics. Forty two Salmonella strains were isolated from 42(2.7% of 1,577 caecal samples of chicks, and their serotypes were S typhimurium 10, S typhimurium var Copenhagen 5, S infantis 4, S thompson 3, and untypable 20. The isolation rate of Salmonella varied from 0 to 5.1% in 6 hatcheries and that of Salmonella from 5 broiler farms was 10. 5%. Biotypes of 10 S typhimurium and 5 S typhimurium var Copenhagen strains isolated from chicks of hatcheries and broiler farms were biotype 2(86.6%), 8(6.7%), and 10a(6.7%), and 26i(6.7%) according to Duguid's scheme. Antibiotic susceptibility test of Salmonella isolated were performed by agar dilution method, using 9 antibiotics as follows: ampicillin(Am), chloramphenicol(Cm), gentamicin(Gm), kanamycin(Km), nalidixic acid(Na), rifampicin(Rf), streptomycin(Sm), sulfadimethoxine(Su), and tetracycline(Tc), All the strains were sensitive to RF. But 8 strans(23.8%) were resistant to one or more drugs and the most common resistance patterns of transferred R plasmids were SmSuGm and SmSu. Among 42 isolates, one had transferable citrate utilizing plasmid. S typhimurium and S typhimurium var copenhagen strains were resistant to killing by 90% normal guinea pig serum.

• 대한수의학회지
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• 제23권2호
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• pp.173-178
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• 1983

This paper deals with the isolation of citrate-utilizing variants of Escherichia coli ($Cit^+$ E. coli) from the animals, their biochemical reactivity and antibiotic susceptibility, and whether the citrate utilizing ability is transmissible. One hundred arid twenty-three isolates of $Cit^+$ E. coli were obtained from cattle and pigs. but from other animals, no isolates were obtaied. Antibiotic susceptibility testing of $Cit^+$ E. coli was performed by the agar dilution method, using the following 9 antibiotics, chloramphenicol(CP), tetracycline(TC), streptomycine(SM), kanamycin(KM), colistin(CL), gentamicin(GM), cephaloridine(CR), aminobenzycillin and nalidixic acid(NA). All the variants tested were susceptible to KM, CL, GM, CR and NA. Of all the variants, 80(65%) were resistant to the drugs tested and resistance to TC and SM was most frequent. The transmission of the ability to utilize citrate on Simmons citrate agar at $37^{\circ}C$ was demonstrated in 78(67.8%) out of the 115 $Cit^+$ E. coli. There were no significant difference in the transfer rates of citrate utilizing ability between resistant and susceptible variants to above 9 drugs. Of 123 isolates, 8 were lost their citrate utilizing ability, spontaneously.

• 대한수의학회지
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• 제19권2호
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• pp.121-126
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• 1979

대장균 설사중에 걸린 어린 돼지, 송아지, 어린 양에서 분리한 대장균 126주의 항생제와 화학요법제(15종)에 대한 감수성을 disc diffusion technique로 조사한 성적은 다음과 같다. 1. 어린 돼지에서 분리한 62주의 대장균은 gentamicin(GM)에 100%, colistin(CL)에 96.8%, kanamycin(KM)에 93.5%, neomycin(NM)에는 91.9%가 감수성을 가지고 있었으나 ampicillin(AM), erythromycin(EM), lincomycin (LM), novobiocin (NB), penicillin (PC), streptomycin(SM), tetracycline(TC), sulfaisodimidin(SU)에는 내성을 가지고 있었다. chloramphenicol(CP), sulfamethoxazole-trimethoprim(SXT), cephalosporin(CE)에는 각각 75.8%, 64.5%, 50%가 감수성이 있었다. 2. 송아지에서 분리한 32주의 대장균은 GM에 100%, CL에는 87.5%, SXT에는 66.7%가 감수성이 있었으나 CP와 KM에는 각각 40.6%, SU에는 56.2% NM에는 62.5%, SM에는 87.5%가 내성을 가지고 있었다. EM, LM, NB, PC에는 전혀 감수성이 없었으며 AM, SM, TC에도 고도의 내성을 가지고 있었다. 3. 어린 양에서 분리한 32주의 대장균은 GM과CL에 100%, CP에 96.9%, KM과 NM에 90.6%가 감수성이 있었다. SM과 SU에도 71.9%나 감수성이 있었으나 CM, EM, LM, PC, TC에는 대부분 내성을 가지고 있었다. AM에는 21.9%가 감수성이 있었다. 4. 2종류 이상의 약제에 내성을 가진 대장균의 AM, CE, CP, CL, GM, KM, NM. SM, TC, SU등 10종의 약제에 대한 multiple drug resistance pattern(MDRP)을 조사한 바 돼지 유래 약제내성 대장균의 MDRP는 18가지였으며 이중 가장 빈도가 높은 것은 AM, CE, SM, TC, SU 내성형으로 전체의 24.2%나 되었다. 송아지 유래 약제내성 대장균의 MDRP는 17가지였으며, AM, CE, CP, KM, NM, SM, TC, SU 내성형이 28.1%로 가장 빈도가 높았다. 반면에 어린 양에서 분리한 대장균의 MDRP는 9가지였으며 AM, CE, SU의 3약제 내성형이 40.6%로 가장 많았다.

• Experimental and Molecular Medicine
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• 제50권11호
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• pp.14.1-14.14
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• 2018

The link between antibiotic treatment and IF-associated liver disease (IFALD) is unclear. Here, we study the effect of antibiotic treatment on bile acid (BA) metabolism and investigate the involved mechanisms. The results showed that pediatric IF patients with cholestasis had a significantly lower abundance of BA-biotransforming bacteria than patients without cholestasis. In addition, the BA composition was altered in the serum, feces, and liver of pediatric IF patients with cholestasis, as reflected by the increased proportion of primary BAs. In the ileum, farnesoid X receptor (FXR) expression was reduced in patients with cholestasis. Correspondingly, the serum FGF19 levels decreased significantly in patients with cholestasis. In the liver, the expression of the rate-limiting enzyme in bile salt synthesis, cytochrome P450 7a1 (CYP7A1), increased noticeably in IF patients with cholestasis. In mice, we showed that oral antibiotics (gentamicin, GM or vancomycin, VCM) reduced colonic microbial diversity, with a decrease in both Gram-negative bacteria (GM affected Eubacterium and Bacteroides) and Gram-positive bacteria (VCM affected Clostridium, Bifidobacterium and Lactobacillus). Concomitantly, treatment with GM or VCM decreased secondary BAs in the colonic contents, with a simultaneous increase in primary BAs in plasma. Moreover, the changes in the colonic BA profile especially that of tauro-beta-muricholic acid ($T{\beta}MCA$), were predominantly associated with the inhibition of the FXR and further altered BA synthesis and transport. In conclusion, the administration of antibiotics significantly decreased the intestinal microbiota diversity and subsequently altered the BA composition. The alterations in BA composition contributed to cholestasis in IF patients by regulating FXR signaling.

• 한국어병학회지
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• 제7권1호
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• pp.37-46
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• 1994

서해안 일원의 가온 양만장 사육조로부터 분리한 E. tarda균에 대한 약제내성검사 및 내성균의 내성인자 전달 시험을 실시하였다. 공시한 항생제에 대한 내성률은 LM, PM, SD, SF 등에는 100%, AP, CH, SM, OT 및 CP 등에는 89% 이상, OA 및 KM에는 70% 정도 그리고 AK, GM 및 EF 등에는 30% 이하의 내성률을 보였으며, 이와같은 내성률은 각 양만장에서 분리한 균주간에 차이를 보이지 않았다. 내성유형은 총 34유형으로 모든 분리균주가 8~14제의 다제내성을 보였으며, 그 중 LM PM SD SF CP CH SM OT AP OA KM(22주, 21.4%) 및 LM PM SD SF CP CH SM OT AP OA(12주, 11.7%) 유형등이 고빈도로 출현하였다. 내성균의 내성인자 전달유형은 총 55형으로 단제에서 13제까지의 다양한 내성인자가 전달되었는데, 그 중 LM PM SD SF CP CH SM OT AP OA(10주. 10%), LM PM SD SF CP CH SM OT AP OA KM(7주, 7%) 및 LM PM SD SF CP CH AP OA(7주, 7%) 등의 다제내성유형이 고빈도의 전달률을 보였으며, 약재별로는 GM, EF 및 AK 등에는 저빈도(0~20%), OT, SM, KM 및 OA 등에는 중등도(49~62%), AP, PM, LM, SF, CP, CH 및 SD 등에는 고빈도(71~94%)로 내성인자를 전달하였다.

• Journal of Microbiology and Biotechnology
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• 제19권12호
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• pp.1576-1581
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• 2009

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has led to an urgent need for the discovery and development of new antibacterial agents. As part of an ongoing investigation into the antibacterial properties of natural products, 20-hydroxyecdysone (20E), isolated from the roots of Achyranthes japonica Nakai, was found to be active against MRSA, either alone or in combination with ampicillin (AM) or gentamicin (GM), via checkerboard assay. This study investigated the antibacterial activity of 20E, which exhibited poor antibacterial activity ($MIC=250-500\;{\mu}g/ml$) against MRSA tested. The combined activity of AM or GE plus 20E against MRSA resulted in fractional inhibitory concentractions (FICs) ranging from 4.00 to $0.031\;{\mu}g/ml$, respectively. Meanwhile, the FIC index ranged from 0.16-4.50, indicating a marked synergistic relationship between AM, GE, and 20E against MRSA. Time-kill assays also showed a remarkable decrease between the combination and the more active compound. Therefore, this study demonstrated that AM, GE, and 20E can act synergistically in inhibiting MRSA in vitro.

• 대한수의학회지
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• 제44권2호
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• pp.217-224
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• 2004

This study was carried out to investigate the antibiotic resistance pattern of Listeria spp. and Staphylococcus aureus. A total of 17 (14.8%) L. monocytogenes, 13 (11.3%) L. innocua, 7 (7%) L. welshimeri, and 83 (72.2%) S. aureus were isolated from commercial poultry carcasses in Seoul and Kyonggi province during the period between 2001 and 2003. Antibiotic susceptibility test of all Listeria strains isolated was performed by the disk agar diffusion method. Antibiotics used in the study were as follows; Amikacin (An), Ampicillin (Am), Cephalothin (Cf), Chloramphenicol (C), Ciprofloxacin (Cip), Erythromycin (E), Gentamicin (Gm), Imipenem (Ipm), Kanamycin (K), Minocycline (Mi), Neomycin (N), Norfloxacin (Nor), Ofloxacin (Ofx), Penicillin (P), Streptomycin (S), Tetracycline (Te), Tobramycin (Nn), Trimethoprim (Tmp), Trimethoprim/Sulfamethoxazloe (Sxt), and Vancomycin (Va). The antibiotic resistance pattern of S. aureus isolates was performed by the disk agar diffusion method. For the latter program, antibiotics used to the study were as follows; Cf, C, Cip, Clindamycin (Cc), E, Gm, Ipm, Nafcillin (Nf), Oxacillin (Ox), P, Te, Sxt, and Va. Of the 17 L. monocytogenes isolates, 94.1% were resistant to Te, 88.2% to Mi, 11.8% to Nor, 11.8% to S, 5.9% to Cip, and 5.9% to C. Of 13 L. innocua, 53.8% were resistant to Te, 23.1% to Mi, 23.1% to S, 7.7% to Cip, and 7.7% to Nor. Of 7 L. welshimeri, 57.1% were resistant to Te, and 14.3% to Am. Of 83 S. aureus, 100% were resistant to Te, 86.7% to Gm, 34.9% to P, 15.7% to Cip, 12% to Cc, 9.6% to E. The multiple antibiotic resistance patterns of L. monocytogenes isolates were observed in Te Mi Cip (5.9%), Te Mi Nor (5.9%), Te Mi (76.5%), and Te Nor (5.9%). Multiple antibiotic resistance was also found in L. innocua isolates. Resistant to Te Mi S Cip Nor was 7.7%, Te Mi S (7.7%), Te Mi (7.7%), and was 7.7% to Te S. Antibiotic resistance patterns for S. aureus isolats were demonstrated to Te Gm P Cip Cc E (6.0%), Te Gm Cip Cc E (3.6%), Te Gm P Cc (1.2%), Te Gm P (15.6%), Te Gm Cip (2.4%), Te P Cip (2.4%), Te Gm Cc (1.2%), Te Gm (56.6%), Te P (9.6%), and to Te Cip (1.2%). The results of this study suggest a high incidence of Lsteria spp. and S. aureus on poultry carcasses. The contaminated poultry carcasses may be a potential vehicle for foodborne infections due to multiple antimicrobial resistant organisms.

• 대한미생물학회지
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• 제20권1호
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• pp.1-11
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• 1985

A total of 211 strains of Staphylococcus aureus which included 118 strains isolated from various clinical specimens of admitted patients of University Hospital with systemic or severe cases of infection and 93 strains from infected skin diseases of out-patients of dermatology clinic located in rural area, were tested for the antimicrobial susceptibility to the 12 drugs of common use and the phage typing. An these were subjected to the study of plasmid profile analysis for the molecular epidemiology of nosocomial infections. University Hospital(UH) isolates showed higher frequency of resistance than local clinic(LC) isolates against 10 drugs excluding tetracycline(Tc), and trimethoprim(Tp). The MIC of UH isolates were above than $128{\mu}g/ml$ against 9 drugs except Tc, gentamicin(Gm), and Tp, but LC isolates did not show such a high level of MIC. There was difference of MIC needed to inhibit 90% of strains(MIC90) against each drugs tested between two groups of UH and LC isolates. UH isolates showed 2 to 4 times higher value of MIC90 by two-fold serial dilution of drug concentration than LC isolates. Tp was considered as an effective drug in treatment of staphylococcal infections whereas ampicillin and Gm were appeared to be ineffective. Seventy-three strains(61.9%) of UH isolates and 70(69.9%) of LC were typable with phages from Colindale Reference Laboratory. The prevailing phage type of UH isolates belonged to lytic group II were 27 strains(22.9%) and those of LC isolates belonged to lytic group II were 23 strains(24.7%). Thirteen strains(11.0%) of UH isolates were multiply resistant to more than 5 drugs to 10 drugs but none of LC isolates. Through the lysis method of Kado and Liu followed by agarose gel electrophoresis, none of 211 strains showed plasmid profile. These results were confirmed by re-examination through the method of Birnboim and Doly.

• Clinical and Experimental Pediatrics
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• 제54권2호
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• pp.79-85
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• 2011

Purpose: We studied the differences in the antibiotic susceptibilities of the microorganisms that causeing urinary tract infections (UTI) in children to obtain useful information on appropriate drug selection for childhood UTI. Methods: We retrospectively analyzed the antibiotic susceptibilities of 429 microorganisms isolated from 900 patients diagnosed with UTI in the Department of Pediatrics, Chungbuk National University Hospital, from 2003 to 2008. Results: The most common causative microorganisms for UTI were Escherichia coli (81.4%), Klebsiella pneumoniae (8.4%), Enterobacter spp. (1.7%), and Proteus spp. (0.4%). E. coli showed relatively high susceptibility as compared to imipenem (100%), amikacin (97.7%), aztreonam (97.9%), cefepime (97.7%), and ceftriaxone (97.1%), while it showed relatively low susceptibility to gentamicin (GM) (79.0%), trimethoprim/sulfamethoxazole (TMP/SMX) (68.7%), ampicillin/sulbactam (33.0%), and ampicillin (AMP) (28.6%). There were no significant differences in the image findings for causative microorganisms. Conclusion: Gram-negative organisms showed high susceptibility to amikacin and third-generation cephalosporins, and low susceptibility to AMP, GM, and TMP/SMX. Therefore, the use of AMP or TMP/SMX as the first choice in empirical and prophylactic treatment of childhood UTI in Korea should be reconsidered and investigated further.

• 대한수의학회지
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• 제26권1호
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• pp.79-85
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• 1986

This paper deals with the isolation of Salmonella on 3 herds during the period from May 1984 to May 1985. Isolated Salmonella were examined for serotypes, adhesive fimbriae, antibiotic susceptibility and detection of R plasmid. The results were as follows; Of total 1505 cattle, 24 Salmonella were isolated from 18 cattle (1.2%) and their serotypes were S. enteritidis (9 strains), S. derby(4 strains), S. infantis (1 strain), $C_1$ group(8 strains), $C_2$ group(1 strain) and untypable(1 strain). Twelve strains of Salmonella were isolated from 227 cattle with diarrhea and their serotypes were S. enteritidis(4 strains), S. derby(3 strains), S. infantis(1 strain), $C_1$ group(3 strains) and untypable(1 strain). The isolation rate of Salmonella in cattle varied from 1.6 to 0.9% in 3 herds, it was higher in summer and autumn and lower with the age. Of total 24 strains, 23 were adhesive type 1 fimbriae. Antibiotic susceptibility test of Salmonella isolated was performed by the agar dilution method, using 9 antibiotics as follows: ampicillin(Am), chloramphenicol(Cm), gentamicin(Gm), kanamycin(Km), nalidixic acid(Na), rifampicin(Rf), streptomycin(Sm), sulfadimethoxine(Su) and tetracycline(Tc). All the strains tested were susceptible to Am, Cm, Gm, Km, Na, Rf and Tc. Of total 24 strains, 23(95.8%) were resistant to Su and 14(58.3%) to Sm. Of the 23 resistant Salmonella strains, all the strains were found to carry R plasmid. Among them, two strains which had the R plasmid conferring SmSu resistance was transferable at $25^{\circ}C$ only.