• The Journal of the Korean Society for Microbiology
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• v.14 no.1
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• pp.49-61
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• 1979

Two hundred and ninety-five strains of Peudomonas aeruginosa isolated from clinical sources were tested for drug resistance and demonstration of R plasmids by intraspecies conjugation system. Sixty strains were found highly resistant to two or more of drugs. The rate of resistant strains were 38.9% to kanamycin(km), 33.2% to streptomydn(sm), 22.7% to sulfisomidine(Sa), 14.2% to chloramphenicol(Cp), 13.8% to tetracycline(Tc), 3.0% to carbenicillin(Cb), and to gentamicin(Gm), respectively. But no strains was resistant to nalidixic acid and colistine. They were resistant to per milliliter to more than $400{\mu}g$ per ml. of Tc, $800{\mu}g$ per ml of Cp and of Sm, $6,400{\mu}g$ per ml. of Sa, $200{\mu}g$ per ml. of Cb, $100{\mu}g$ per ml. of Gm, and $25{\mu}g$ per ml. of colistine. Forty-three strains of Pseudomonas aeruginosa could be transferred their resistance to Pseudomonas aeruginosa 2-70, 1005 rifampin resistant FP-auxotrophic mutant. Of sixty multiple resistant strains, forty-three(71.6%) demonstrated R plasmids; nineteen carried resistance to(Tc Cp Sm Sa), six to(Tc Cp Sm), three to(Tc Cp Sa), and Cp, five to(Tc Sm Sa), two to(Tc Sa), (Cp Sm) and Tc, and one to(Cp Sm Sa). Degree of resistance of recipients recieving R plasmids from donors were almost the same level of resistance as the donor in regardless of mating temperature at $25^{\circ}C$ and $37^{\circ}C$. Resistance to Tc, Sm, and Sa were transferred to a very few of recipient cells at five minutes after mating with donor and recipient cells but resistance to Cp were transferred to the majority of recipient cells. The transfer frequency of Tc, Cp, Sm, and Sa resistance from donors to recipients were from $1.0^{-1.4}\;to\;1.0^{-3.5}$ at $25^{\circ}C$ for 18 hours of incubation and were from $1.0^{-1.5}\;to\;1.0^{-3.5}$ at $37^{\circ}C$ for 18 hours of incubation.

• Korean Journal of Veterinary Service
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• v.33 no.3
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• pp.241-248
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• 2010

The present study was conducted to investigate isolation and antimicrobial resistance ratio of E. coli, E. faecium and E. faecalis from feces(l50 samples) and carcasses (150 samples) on slaughtered pigs from 6 slaughterhouse of 13 cities in the Gyeongnam during the period from January 2009 to December 2009. Isolation ratio of E. coli from feces and carcasses were 98 (65.3%) and 110(73.3%), respectively, and simultaneously, E. faecalis and E. faecium from feces and carcasses were isolated 21 (14%), 52(34.7%) and 18(12%), 14 (9.3%), respectively. All E. coli isolated from feces and carcasses except cefepime (0%) and ceftiofur (0%) were exhibited 2.4~83.6% of resistance to teteracycline (83.6%), ampicillin (68.2%), streptomycin (60%), chloram-phenicol (53.8%) and cephalothin (2.4%). All E. faecalis isolated from feces and carcasses except penicillin(0%) and vancomycin (0%) were exhibited 2.7~80.8% of resistance to teteracycline (80.8%), quinupristin/dalfopristin (78%), erythromycin (56.1%), streptomycin (43.8%) and bacitracin (2.7%). All E. faecium isolated from feces and carcasses except gentamicin (0%), vancomycin (0%), florfenicol (0%), linezloid (0%) and bacitracin (0%) were exhibited 3.1~53.1% of resistance to rifampin (53.1%), erythromycin and tetracycline (25%), penicillin (15.6%), ciprofloxacin (9.3%), and streptomycin, chloramphenicol, and quinupristin/dalfopristin (3.1%). According to the heard size, resistance ratio of E. coli strains isolated from feces and carcasses in slaughtered pigs-breeding farms over 1,500 heard to tetracycline, ampicillin, streptomycin and chloramphenicol showed higher resistance ratio (1.0~16.8%) than those of farms-breeding under 1,500 heard. From the our results, we suggest that a few of antimicrobials were used in the Gyeongnam than the other cities.

• Journal of Environmental Health Sciences
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• v.45 no.3
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• pp.222-230
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• 2019

Objectives: This study aims to evaluate water quality in terms of microorganisms and identify the antibiotic resistance of Enterococci isolated from the recycling water in floor fountains at three parks and one reservoir in the Gwangju area. Methods: Water samples were analyzed for Enterococci using membrane Enterococcus indoxyl ${\beta}$ d glucoside agar (mEI) as described in USEPA Method 1600. The vancomycin-resistant Enterococci with VanA and VanB were identified by PCR. An examination of the antibiotic resistance of isolates against 14 antibiotics was performed by the disk diffusion method. Results: The drinking water quality criterion was exceeded for total colony counts in 68% of all recycling water samples. The average concentration of total califorms and fecal coliforms was 139,325 and 413 CFU/100 mL, respectively. VanA and VanB were not detected from the isolates. We found the antibiotic resistant Enterococci strains to be E. faecalis, E. faecium, E. durans, E. mundtii, E. hirae, and E. thailandicus. The isolates were resistant to Rifampin (50%), Erythromycin (25.8%), Tetracycline (10.2%), Nitrofurantoin (8.1%), Minocycline (3.1%), Erythromycin (1.2%), Penicillin (0.7%), Norfloxacin (0.5%), and Teicoplanin (0.5%) among the 14 antibiotics tested. Antibiotic resistance tests for Enterococci from the recycling water of floor fountains resulted in 30.2% showing resistance to two or more antibiotics. Conclusions: These results showed that the multi-antibiotic resistance of Enterococci, E. coli, and others should be investigated continuously in each environment field.

• Korean Journal of Veterinary Service
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• v.33 no.3
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• pp.255-261
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• 2010

At the present study, it was aimed to explore the states of antimicrobial resistant Staphylococcus aureus isolates from 320 pigs and cattle carcass (160 pigs and 160 cattle) slaughtered in Busan province from March 2008 to November 2009. Among 320 samples, 26 of Staphylococcus aureus were isolated from pigs (10.6%) and cattle (5.6%). In antimicrobial susceptibility test, all of the isolates were demonstrated susceptibility to oxacillin, cefoxitin, cephalothin, vancomycin, rifampin and linezolid. But the isolates were showed resistance other antibiotics in order of penicillin (92.3%), gentamicin (76.9%), tetracycline (69.2%), erythromycin (65.4%), and clindamycin (61.5%). In case of enterotoxin production, 7.7% of 2 strains produced enterotoxin A.

• Korean Journal of Veterinary Service
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• v.33 no.3
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• pp.263-269
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• 2010

The antimicrobial susceptibility of 73 strains of Staphylococcus aureus isolated from dogs and cats was determined against 16 antimicrobial agents. All isolates were susceptible to cephalothin (CF), vancomycin (VA), rifampin (RA), quinupristin-dalfopristin (SYN) and linezolid (LZD), whereas more than 86.3% of the isolates were resistant to penicillin (P). In the case of enterotoxin production, 8.2% of 73 strains produced enterotoxin A and 1 strain produced enterotoxin C. Appropriate protocols for antimicrobial agents and strategies to reduce antimicrobial resistance will need to be investigated in the future.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.3
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• pp.155-163
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• 2005

The purpose of this study is to investigate the carrier rate of S. aureus in the community, antibiotic susceptibility patterns of the organism, detection of MRSA and mecA gene in MRSA. Identification and antibiotic resistance patterns of S. aureus and MRSA were done by MicroScan Panels. MRSA strain was confirmed by disk diffusion method using oxacillin disk. The mecA gene in MRSA was detected by PCR. Eighty-four strains (27.4%) of S. aureus were isolated from the nasal specimens of 307 university students in Busan in 2004. Sixty-eight strains (81.9%) of 83 S. aureus were resistant to penicllin, 16 strains(19.3%) to erythromycin, 15 strains (18.1%) to gentamicin, 12 strains (14.5%) to tetracycline, 6 strains (7.2%) to chloramphenicol, 3 strains (3.6%) to ofloxacin, 2 strains (2.4%) to cefepime, clindamycin, imipenem, meropenem, norfloxacin, respectively. One strain (1.2%) was resistant to ciprofloxacin, cefazolin, cefotaxime, cefuroxime, and oxacillin. And all the strains (100%) of 84 S. aureus were susceptible to amoxicilin/K clavulanate, ticarcillin/K clavulanate, trimethoprim/sulfamethoxazole, rifampin, syncroid, teicoplanin, and vancomycin. One strain of 84 S. aureus isolates was methicillin-resistant Staphylococcus aureus (MRSA). The mecA gene was detected from the MRSA strain.

• Korean Journal of Clinical Pharmacy
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• v.9 no.1
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• pp.1-14
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• 1999

Vancomycin-resistant Enterococci (VRE) have recently emerged in Korean hospitals, as well as in those of other countries. VRE have been partially attributed to the overuse and misuse of vancomycin. The mecbanisms of VRE resistance are related to VanA, VanB, and VanC. Both VanA and VanB produce abnormal ligase enzymes to form D-ala-D-lactate termini in E. faecium and E. faecalis, instead of D-ala-D-ala termini. Meanwhile, Van C produces D-ser-D-ala termini in E. gallinarum and E. casseliflavus. These abnormal termini have a low affinity to vancomycin. As a result, VRE avoid the activity of vancomycin by these mechanisms. Unfortunately, there is no approved therapy for the treatment of VRE. Thus, available but uncommonly prescribed antibiotics (due to their toxicity or unproven efficacy) may become possible options. They include chloramphenicol, novobiocin, fosfomycin, and bacitracin. The combination therapy of available agents may also be the other options. They include high doses of a penicillin- or ampicillin-aminoglycoside combination, high doses of an ampicillin/sulbactam and aminoglyoosidcs combination, an ampicillin and vancomycin combination, and a ciprofloxacin, aminoglycosides, and rifampin combination. With respect to the near future, many types of investigational agents will most likely expand their treatment options for VRE. Teicoplanin, a glycopeptide, can be used for VanB- and VanC-related VRE. LY333328, a new generation of glycopeptide, is effective in treating VanA as well as VanB and VanC. RP59500 (quinupristin/dalfopristin), a streptogramin, is effective in treating vancomycin-resistant E. faecium. New generation quinolones (especially clinatloxacin) are potential options for the treatment of VRE, even though they cannot work as effectively against VRE as they can against Staphylococci. Both glycylcyclines (a new generation of tetracyclines) and ketolides (a new generation of macrolides) show good activity against Enterococci, regardless of vancomycin susceptibility. Oxazolidinones (i. e. eperezolid and 1inezolid) and everninomicins (i. e. SCH27899) are new groups of antibiotics, which also demonstrate good activity against VRE. It is imperative that clinical pharmacists take the responsibility of investigating new treatment options for VRE in order to combat this growing problem throughout the world.

• Tuberculosis and Respiratory Diseases
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• v.85 no.1
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• pp.89-95
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• 2022

Background: With the introduction of Xpert MTB/RIF assay (Xpert), its incorporation into tuberculosis (TB) diagnostic algorithm has become an important issue. The aim of this study was to evaluate the performance of the Xpert assay in comparison with a commercial polymerase chain reaction (PCR) assay. Methods: Medical records of patients having results of both Xpert and AdvanSure TB/NTM real-time PCR (AdvanSure) assays using the same bronchial washing specimens were retrospectively reviewed. Results: Of the 1,297 patients included in this study, 205 (15.8%) were diagnosed with pulmonary TB. Using mycobacterial culture as the reference method, sensitivity of the Xpert assay using smear-positive specimens was 97.5%, which was comparable to that of the AdvanSure assay (96.3%, p=0.193). However, the sensitivity of the Xpert assay using smear-negative specimens was 70.6%, which was significantly higher than that of the AdvanSure assay (52.9%, p=0.018). Usng phenotypic drug susceptibility testing as the reference method, sensitivity and specificity for detecting rifampicin resistance were 100% and 99.1%, respectively. Moreover, a median turnaround time of the Xpert assay was 1 day, which was significantly shorter than 3 days of the AdvanSure assay (p<0.001). Conclusion: In comparison with the AdvanSure assay, the Xpert assay had a higher sensitivity using smear-negative specimens, a shorter turnaround time, and could reliably predict rifampin resistance. Therefore, the Xpert assay might be preferentially recommended over TB-PCR in Korean TB diagnostic algorithm.

• Tuberculosis and Respiratory Diseases
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• v.86 no.1
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• pp.47-56
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• 2023

Background: There is a global increase in isolation of nontuberculous mycobacteria (NTM). The aim of the study was to analyze longitudinal trends of NTM identification and pattern of antimicrobial susceptibility testing. Methods: NTM recovery rates, distribution of NTM species identification, and antimicrobial susceptibility pattern of NTM at Pusan National University Yangsan Hospital between January 2016 and December 2020 were retrospectively analyzed. Results: A total of 52,456 specimens from 21,264 patients were submitted for mycobacterial culture, of which 2,521 from 1,410 patients were NTM positive over five years (January 2016 to December 2020). NTM isolation showed an increasing trend from 2016 to 2020 (p<0.001, test for trend) mainly caused by Mycobacterium avium complex. The vast majority of M. avium complex were susceptible to key agents clarithromycin and amikacin. For Mycobacterium kansasii, resistance to rifampin and clarithromycin is rare. Amikacin was the most effective drug against Mycobacterium abscessus subspecies abscessus and Mycobacterium subspecies massiliense. Most of M. subspecies massiliense were susceptible to clarithromycin, while the majority of M. abscessus subspecies abscessus were resistant to clarithromycin (p<0.001). Conclusion: There was an increasing trend of NTM isolation in our hospital. Resistance to key drugs was uncommon for most NTM species except for M. abscessus subspecies abscessus against clarithromycin.

• The Journal of the Korean Society for Microbiology
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• v.22 no.1
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• pp.35-53
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• 1987

Multiply resistant Shigella strains isolated in Taegu area were subjected for the characterization of R plasmids. All strains isolated in 1984 and 1985 were susceptible to gentamicin, amikacin, and cephalothin, and most strains were susceptible to kanamycin (Km) and rifampin by agar dilution antimicrobial susceptibility test. The resistance frequency of S. flexneri against ampicillin (Ap) was higher than that of S. sonnei. The strains resistant to sulfisomidine (Su) and trimethoprim (Tp) were found at higher frequency in S. sonnei than in S. flexneri. The most prevalent resistance pattern of S. flexneri was chloramphenicol (Cm) tetracycline (Tc) streptomycin (Sm) Ap, followed by the pattern of CmTcSmSuApTp, CmTcSmSuApTp nalidixic acid, and CmTcSmSuAp in the decreasing order. The antibiogram of CmTcSmSuTp was found to be the most frequent pattern in S. sonnei. The ratio of conjugal transfer of S. flexneri was 47% and 75% of S. sonnei. The average number of plasmid harboring in Shigella was 4 and the size of plasmid ranged 1.3 to 134 megadalton (Mdal). Most S. flexneri carried plasmids of 2 to 3 Mdal and S. sonnei carried those of 3 to 4 Mdal size. The sizes of conjugative plasmids ranged 40-90 Mdal. The incompatibility group (Inc) F II plasmids (54-59 Mdal) were most frequent and rare Inc B plasmids (60 Mdal) of isolates in 1979 and 1980 and Inc FI (87 Mdal) of 1983 isolates were able to be classified by the colony test with standard reference plasmids. The R plasmids of known Inc group were tested for the restriction endonuclease analysis. The pattern of plasmids digested by EcoRl were apparently different by the Inc group but there was no significant difference between species or by the resistance patterns. Nonconjugative plasmids and their phenotypes were identified by transformation test. The transformants were resistant to less than two drugs. Colicin producing transformants carried the Col plasmid of 3.7 or 3.9 Mdal size. $Ap^r$ plasmids derived from S. sonnei were found to be mobilized by transfer factor RT641 to E. coli #CS100. $Ap^r$ plasm ids of same size shared by S. flexneri, S. sonnei, and E. coli were digested with Pstl. All of them showed two restriction fragments of 2.8 kilobase(kb) and 0.7kb. Other plasmids ($Sm^r\;Su^r$) derived from S. flexneri, S. boydii, and S. sonnei were digested with Pstl and they showed same restriction fragment patterns of 3.1kb and 2.9kb. The plasmid profiles of three strains of S. sonnei producing colicin and showing same resistance pattern of CmTcSmSuApTpKm appeared to be similar. Restriction patterns by EcoRl and the behavior of plasmids in conjugation or transformation process were also similar between those plasmids. The restriction patterns were significantly different between the plasmids of Inc FI group and those of unclassified Inc group.