• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.432-440
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• 2023

Irrational and injudicious use of antibiotics, easy availability of them as over-the-counter drugs in economically developing countries, and unavailability of regulatory policies governing antimicrobial use in agriculture, animals, and humans, has led to the development of multi-drug resistance (MDR) bacteria. The use of medicinal plants can be considered as an alternative, with a consequent impact on microbial resistance. We tested extracts of Piper longum fruits as new natural products as agents for reversing the resistance to antibiotics. Six crude extracts of P. longum fruits were utilized against a clinical isolate of multidrug-resistant Staphylococcus aureus.The antibiotic susceptibility testing disc method was used in the antibiotic resistance reversal analysis. Apart from cefoxitin and erythromycin, all other antibiotics used (lincosamides [clindamycin], quinolones [levofloxacin and ciprofloxacin], and aminoglycosides [amikacin and gentamicin]) were enhanced by P. longum extracts. The extracts that showed the greatest synergy with the antibiotics were EAPL (ethyl acetate [extract of] P. longum), n-BPL (n-butanol [extract of] P. longum), and MPL (methanolic [extract of] P. longum The results of this study suggest that P. longum extracts have the ability to increase the effectiveness of different classes of antibiotics and reverse their resistance. However, future studies are needed to elucidate the molecular mechanisms behind the synergy between antibiotic and phytocompound(s) and identify the active biomolecules of P. longum responsible for the synergy in S. aureus.

• Journal of the Korean Chemical Society
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• v.53 no.1
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• pp.17-26
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• 2009

Hydrazones of isonicotinic acid hydrazide, viz., N-isonicotinamido-furfuralaldimine (INH-FFL), N-isonicotnamido-cinnamalidine (INH-CIN) and N-isonicotnamido-3',4',5'-trimethoxybenzaldimine (INH-TMB) were prepared by reacting isonicotinic acid hydrazide with respective aromatic aldehydes, i.e., furfural, cinnamaldehyde or 3,4,5-trimethoxy-benzaldehyde. A new series of fifteen complexes of cobalt(II) with these new hydrazones, INH-FFL, INH-CIN and INH-TMB, were synthesized by their reaction with cobalt(II) salts. The infrared spectral data reveal that hydrazone ligands behave as a bidentate ligand with N, O donor sequence towards the $Co^{2+}$ ion. The complexes were characterized on the basis of elemental analysis, magnetic susceptibility, conductivity, infrared and electronic spectral measurements. Analytical data reveal that the complexes have general composition [Co($L)_2X_2]\;and\;[Co(L)_3](ClO_4)_2$ where L= INH-FFL, INH-CIN or INH-TMB and X = $Cl^-,{NO_3}-,\;NCS^-\;or\;CH_3COO^-.$ The thermal behaviour of the complexes were studied using thermogravimetrictechnique. Electronic spectral results and magnetic susceptibility measurements are consistent with the adoption of a six-coordinate geometry for the cobalt(II) chelates. The antimicrobial properties of cobalt(II) complexes and few standard drugs have revealed that the complexes have very moderate antibacterial activities.

• Korean Journal of Veterinary Service
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• v.24 no.1
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• pp.31-41
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• 2001

This study was carried out to identify causative agents from california mastitis test(CMT) positive mastitic milk, and to examine the antimicrobial susceptibility of 50 heads in Seongju and Chilgok area of Gyeongbuk province. Sulfadimethoxine sodium(SMS) was intramuscularly administered once to four mastitis Infected dairy cattle at the rate of 10mg/kg body weight. After injection of SMS, the depletion rate of serum and milk from the cattle were periodically measured for five days. The CMT positive number from 50 heads showed 46% and that of 200 quarters was 47(23.5%). From 39 quarters of 47 heads 39 different microorganisms were identified. These organisms were classified into 12 species : Staphylococcus aureus 8(20.5%), Sta hemolyticus 6(15.4%), Streptococcus bovis 4(10.3%), Sta hyicus 3(7.7%), Sta epidemidis. Sta xylosus, Sta sciuri 2(5.1%), Str agalactiae 2(5.1%), Escherichia coli(10.3%), three Enterobacter cloacae(7.7%), two Ent aerogenes(5.1%) and one Salmonella spp(2.6%). As the results of antibiotic susceptibility test, gentamicin(Gm, 11 species 27 strains, 69.5%), cephalotin(Cf, 9 species 24 strains, 61.5%), sulfamethoxazole(Stx, 8 species 14 strains, 43.6%), tetracycline(Tc, 8 species 14 strains, 35.9%), and streptomycin(Sm), lincomycin(Lm), cefoperazon(Cp) and penicillin(Pc) have a highly resistance(7.7% ～5.1%). However, carbenicillin (Cb), amikacin(Ah) have no susceptible for all drugs. The mean residual concentration of SMS in serum according to the time lapsed were showed 33.964 $\pm$ 4.435ppm at the 4 hours after intramuscularly injection(AII). It was significantly(p<.05) decreased to 6.596 $\pm$ 3.402, 0.217 $\pm$ 0.119 and 0.005 $\pm$ 0.004ppm at the 1st, 3rd and 5th day AII. The mean concentration of SMS in milk was significantly(p<.05) decreased from 0.920 $\pm$ 0.42ppm to 0.084 $\pm$ 0.016ppm between 8 hours and 1 day AII. As the results of this experiments, sulfadimethoxine was residued at the level of no less than 0.01ppm in milk on the 2nd day AII. Thus, this results would be able to be used the basic index for prevention of sulfonamides residue in milk after treatment of dairy mastitis.

• Korean Journal of Veterinary Research
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• v.20 no.2
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• pp.85-92
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• 1980

The antimicrobial drug susceptibility of 439 isolates of animal pathogens recovered from various clinical cases during 1978-79 has been investigated by the use of disk diffusion technique. The majority of 308 strains of Eschericihia coli were highly resistant to bacitracin, erythromycin, penicillin, streptomycin and tetracyclinon while only 0.3 per cent of them were resistant to gentamicin and 3.2 per cent to colistin. The percentages of strains resistant to ampicillin, carbenicillin, cephalothin, chloramphenicol and neomycin were 30.5%, 24.7%, 11:4%, 28.2% and 26.2% and repectively. However, none of E. coli cultures of ovine origin were resistant to ampicillin, carbenicillin, chloramphenicol, colistin, gentamicin, kanamycin, and neomycin. A total of 39 patterns of multipe drug1 resistance of 308 strains E. coli against 9 drugs in general use such as ampicillin, cephalothin, chloramphenicol, colistin, gentamicin, kanamycin, neomycin, streptomycin and tetracycline were observed and the most common multiple resistance patterns were SM, TC pattern (20.5%) and AM, CP, KM, NM, SM, TC pattern (9.7%). None of the 43 cultures of salmonella organism from pigs and chickens were resistant to ampicillin, carbenicillin, cephalothin, colistin, gentamicin and kanamycin; and the majority of the cultures were susceptible to chloramphenicol (90.0%), neomycin (97.7%) and tetracycline (93.0%). All the cultures were found to be resistant to bacitracin and penicillin and the rate of resistant strains to erythromycin and s treptomycin being 79.1% and 41.9% respectively. It was found that the majority of 63 cultures of staphylococcal isolates were resistant to lincomycin, penicillin, streptomycin and tetracycline. The percentages of 63 staphylococcal isolates susceptible to gentamicin, nitrofurantoin, cephalothin, ampicillin, methicillin, bacitracin and chloramphenicol were 98.4%, 98.4%, 95.2%, 93.7%, 93.7%, 92.1% and 92.1% respectively. The 25 cultures of streptococcal isolates were resistant in order of prevalence to streptomycin(88.0%), kanamycin(68.0%), gentamicin (44.0%), tetracycline (44.0%) and methicillin (40.0%) wihle the majority of them were sensitive to ampicillin, bacitracin, chloramphenicol and penicillin.

• Korean Journal of Veterinary Research
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• v.46 no.4
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• pp.337-345
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• 2006

The shigellae are common etiological agents of bacillary dysentery in humans and primates. During four years from 2002 to 2005, 22 strains of Shigella spp. were isolated from the diarrheic patients in Seoul region. All of them were identified as S. flexneri by biochemical tests and serotyping. The prevalence of serotypes were variable by year, but the major serotypes were 2a and 3a. In an antimicrobial susceptibility test, all of the isolates were resistant to streptomycin and tetracycline, and susceptible to amikacin, kanamycin, cefoxitin, and gentamicin. All of the isolates showed the multi-resistant patterns over 3 drugs. By analysis of the plasmid profile the isolates were classified into 7 groups (P1~P7). Serotypes 2a and 2b were distributed to P1, P2, P3, and P4. Serotype 3a was differentiated to P5 and serotype 3b, to P6 and serotype 4a, to P7. PCR results showed that all isolates were positive for two virulence genes, ipaH and ial, but none of the strains had stx gene. The set1A and set1B genes were detected from 12 isolates (54.5%) that belonged to serotype 2a and 2b. The sen gene was detected from 19 isolates (86.4%). The 22 isolates showed 12 to 17 DNA fragments in the sizes ranging from 20.5 kb to 1135 kb, resulting in 13 patterns by the PFGE with Not I digestion. The PFGE patterns of the isolates showed the close relation with the serotypes, but no relations with year of isolation and antimicrobial resistance.

• Tuberculosis and Respiratory Diseases
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• v.42 no.1
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• pp.67-75
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• 1995

Background: Although we gain new knowledge, the problem of pneumonia will not be eliminated. We should understand who is at risk, why these people develop this problem, what causes the pneumonia, and how to manage and prevent respiratory infection. To clarify the alterations of the etiologies of bacterial pneumonia we analysed the recent causative organisms and evaluated the therapeutic implications. Methods: A retrospective four-year study of bacterial pneumonia was conducted in Soon Chun Hyang University Hospital. 190 episodes of bacterial pneumonia was investigated. Results: 1) The causative organisms were isolated in 173 cases on the sputum culture: 154 cases (89%) were gram negative bacilli and 19 cases(11%) were gram positive cocci. The major organisms were Pseudomonas species 49 cases(28%), Klebsiella pneumoniae 29 cases(17%), Enterobacter species 25 cases(14%), and Acinetobacter species 20 cases(12%) in decreasing order. Pseudomonas species(13 cases, 34%) were frequently found in nosocomial pneumonia. 2) The causative organisms were isolated in 16 cases on the blood culture: 7 cases(43%) were gram negative bacilli and 9 cases(57%) were gram positive cocci. The major organisms were Staphylococcus aureus(6 cases, 38%), Pseudomonas species(3 cases, 19%) in decreasing order. 3) In the susceptibility test of causative organisms to antimicrobial drugs, Pseudomonas was susceptible to amikacin, ciprofloxacin, aztreonam, ceftazidime(more than 50%) and resistant to piperacillin, gentamicin, carbenicillin(more than 60%). Klebsiella was susceptible to chloramphenicol, gentamicin, cefotetan(more than 70%) and resistant to carbenicillin, ampicillin(more than 70%). Staphylococcus was susceptible to methicillin(64%), and Streptococcus pneumoniae was susceptible to oxacillin(94%). 4) The response rate after antibiotics therapy was 81% and the mortality rate was 19%. Conclusion: As considering the changes of causative organisms and antibiotic resistance, it behooves us to exercise caution in dispending antibiotics in order to maximize their continued efficacy and to do appropiate antibiotics therapy based on cultures and susceptibility test.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.141-149
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• 2017

This study was to investigate the sanitary microbiological aspects of Cheonho Reservoir and its antibiotic resistance in the natural environment to contribute to the public healthcare improvement. Groups of coliforms, were counted at three sites of the Cheonho Reservoir in July and September 2013, and the isolates were identified according to the water pollution process test standards. Antibiotic resistance was evaluated using the Korea National Institute of Health's standard antibiotic susceptibility test. The average coliform counts in Cheonho Reservoir were $2.0{\times}10^3CFU/mL$, 41% of which were identified as Escherichia coli(E. coli). Antibiotic resistance rate in E. coli isolated from Cheonho reservoir was highest in Ampicillin 31.3%, Ticarcillin 25.0%, Cefaxolin and Cefoxitin 18.8% respectively. Convergence multiple resistance patterns, 38,5% presented resistance to 4 durgs, 6 drugs resistance were 7.7%. The more than 2 drugs resistance were 92.3%. Cheonho Reservoir is a public park that accessible to the citizens, further convergence studies are needed to develop sanitary microbiological management practices and study antibiotic resistance of the reservoir.

• Pediatric Infection and Vaccine
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• v.9 no.2
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• pp.163-174
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• 2002

Background : To delineate the changes in the causative agents of neonatal sepsis and their antimicrobial susceptibilities in the neonatal intensive care unit and nursery of Hanyang University Hospital during the past 10 years. Methods : Hospital records of 15,144 patients hospitalized at the NICU and nursery of Hanyang University Hospital from 1989 to 1998 were reviewed and neonates diagnosed of neonatal sepsis were sorted and included in the study. The study period was divided into Period A(the first 5 years) and Period B(the second 5 years) to analyse causative agents and their antimicrobial susceptibilities. Results : Neonatal sepsis was diagnosed in 170 patients(1.1%{Period A 1.2%, Period B 1.0%}) among the total of 15,144 inpatients. Two hundred isolates(Period A 109 isolates, Period B 91 isolates) were identified in 186 blood cultures(Period A 99 cultures, Period B 87 cultures) from 170 patients(Period A 91 patients, Period B 79 patients). The average age at the onset of the disease, when the initial blood culture was drawn, was 12.3 days old(Period A 8.8 days, Period B 16.3 days), and the proportion of the early onset disease was 34.7% in Period A and 23.0% in Period B, indicating that neonatal sepsis developed earlier during Period A. Among the isolated organisms including Gram positive bacteria[132(66.0%)], Gram negative bacteria [60(30.0%)], and fungi[8(4.0%)], coagulase negative Staphylococcus(CNS) was the most common organism(69/34.5%), followed by Staphylococcus aureus(36/18.0%), Klebsiella pneumoniae(17/8.5%), Enterococcus(12/6.0%), Enterobacter cloacae(8/4.0%), Escherichia coli(6/3.0%), and Pseudomonas aeruginosae(5/2.5%). The isolated fungi were Candida parapsilosis, Candida albicans, and Trichosporon pullulans. CNS, S. aureus and Acinetobacter baumannii were isolated more frequently in Period A compared to Period B. Antimicrobial susceptibilities of CNS and S. aureus to methicillin and the first generation cephalo sporins were decreased in Period B compare to Period A, those to aminoglycosides were increased in Period B, and vancomycin resistant strains were not identified. K. pneumoniae, Enterococcus, E. coli, and P. aeruginosa were isolated less frequently in Period B, compared to Period A. For K. pneumoniae, antimicrobial susceptibilities to the first generation cephalosporins were low in both Periods A and B, those to tobramycin and gentamicin were increased in Period B, and those to amikacin, ceftriaxone, and trimethoprim-sulfamethoxazole were high in both Periods A and B. Antimicrobial susceptibilities of Enterococcous to ampicillin, penicillin, and the first generation cephalosporins were decreased in Period B, but vancomycin resistant strains were not identified. Conclusion : The occurrence rate of neonatal sepsis during the past 10 years in the NICU and nursery of the Hanyang University hospital was 1.1%, and the most common causitive agents were CNS and S. aureus, to which the antimicrobial susceptibilities to the first line drugs decreased in the later half of the study period with no vancomycin resistant isolates identified. Group B Streptococcus known to be the most common agent causing neonatal sepsis was not identified, and K. pneumoniae was isolated more commonly during the later half of the study period without decreased antimicrobial susceptibilities.

• 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.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.683-692
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• 2009

The synthesis of a novel series of nickel(II) complexes with new ligands derived from hydrazones of isoniazid have been reported in present work. The complexes have general compositions [$Ni(L)_2X_2$] or $[Ni(L)_3](ClO_4)_2$ {L = N-isonicotinamido-furfuraldimine (INH-FFL), N-isonicotinamido-3',4',5'-trimethoxybenzaldimine (INH-TMB) or N-isonicotinamido-cinnamalidene (INH-CIN) and X = $Cl^-$, ${NO_3}^-$, $ NCS^-$ or $CH_3COO^-$}. The ligands hydrazones behave as neutral bidentates (N and O donor) through the carbonyl oxygen and azomethine nitrogen. The new complexes with octahedral geometry have been characterized by elemental analysis, molecular weight determinations, magnetic susceptibility/moment, thermogravimetric, electrochemical and spectroscopic studies viz. infrared and electronic spectra. On the basis of conductivity measurements in nitrobenzene ($PhNO_2$) solution the [$Ni(L)_2X_2$] and $[Ni(L)_3](ClO_4)_2$ complexes have been found to be non-electrolytes and 1:2 electrolytes, respectively. Thermal properties have also been investigated, which support the geometry of the complexes. Antibacterial and antifungal properties of nickel(II) complexes and few standard drugs have also been examined and it has been observed that the complexes have moderate antibacterial activities.