• Journal of Microbiology and Biotechnology
• /
• 제19권9호
• /
• pp.932-945
• /
• 2009

Several species of Gram-positive bacteria have cell wall peptidoglycan (syn. murein) in which not all of the sugar moieties are N-acetylated. This has recently been shown to be a secondary effect, caused by the action of a peptidoglycan N-acetylglucosamine deacetylase. We have found that the opportunistic pathogen Listeria monocytogenes is unusual in having three enzymes with such activity, two of which remain in the cytoplasm. Here, we examine the enzyme (PgdA) that crosses the cytoplasmic membrane and is localized in the cell wall. We purified a hexa-His-tagged form of PgdA to study its activity and constructed a mutant devoid of functional Lmo0415 (PgdA) protein. L. monocytogenes PgdA protein exhibited peptidoglycan N-acetylglucosamine deacetylase activity with natural substrates (peptidoglycan) from both L. monocytogenes and Escherichia coli as well as the peptidoglycan sugar chain component N-acetylglucosamine, but not with N-acetylmuramic acid. As was reported recently [6], inactivation of the structural gene was not lethal for L. monocytogenes nor did it affect growth rate or morphology of the cells. However, the pgdA mutant was more prone to autolysis induced by such agents as Triton X-100 and EDTA, and is more susceptible to the cationic antimicrobial peptides (CAMP) lysozyme and mutanolysin, using either peptidoglycan muramidases or autolysis-inducing agents. The pgdA mutant was also slightly more susceptible than the wild-type strain to the action of certain beta-lactam antibiotics. Our results indicate that protein PgdA plays a protective physiological role for listerial cells.

• 대한미생물학회지
• /
• 제35권3호
• /
• pp.239-250
• /
• 2000

Sixty-eight clinical isolates of Stenotrophomonas maltophilia from inpatients of 2 university hospitals in Taegu were epidemiologically analyzed by using the minimum inhibitory concentrations of 25 antimicrobial drugs, biochemical reaction, pulsed-field gel elctropgoresis (PFGE), and PCR with enterobacterial repetitive intergenic consensus sequences as primer (ERIC-PCR). 1. All the strains were susceptible to minocycline. More than 57% were susceptible to sulfisomidine (Su), ciprofloxacin (Ci), Ofloploxacin (Of), nalidixic acid (Na), and chloramphenicol (Cm), and $19{\sim}35%$ to ceftazidime (Cd), trimethoprim (Tp), Ticacillin-clavulanic acid, and cefoperazone-sulbactam. Most isolates were resistant to ${\beta}$-lactam antibiotics such as ampicillin (Ap), carbenicillin (Cb), cefotaxim (Ct), cefoxitin (Cx), and aminoglycosides including gentamicin (Gm), tobramycin (Tb), amikacin (Ak). 2. All the isolates were multiply resistant of 5 to 17 drugs and showed 40 different resistance pattern types. 3. All the strains showed very similar biochemical reactions except ${\beta}$-galactosidase and nitrate reduction test. Fourteen strains selected randomly were classified 10 different pattern type by PFGE and ERIC-PCR. These two methods showed identical result. Four strains isolated from wound in 1994 showed similar MIC pattern and identical API 20NE profile, PFGE, and ERIC-PCR pattern indicating episodes of cross-infection among patients. These results indicate that PFGE or ERIC-PCR profile has comparable discriminatory power for epidemiological typing of S. maltophilia.

• Osong Public Health and Research Perspectives
• /
• 제9권6호
• /
• pp.325-333
• /
• 2018

Objectives: The purpose of this study was to determine the presence of IMP and OXA genes in clinical strains of Pseudomonas aeruginosa (P. aeruginosa) that are carriers of the ampC gene. Methods: In this study, 105 clinical isolates of P. aeruginosa were collected. Antibiotic resistance patterns were determined using the disk diffusion method. The strains carrying AmpC enzymes were characterized by a combination disk method. Multiplex-PCR was used to identify resistance and virulence genes, chi-square test was used to determine the relationship between variables. Results: Among 105 isolates of P. aeruginosa, the highest antibiotic resistance was to cefotaxime and aztreonam, and the least resistance was to colictin and ceftazidime. There were 49 isolates (46.66%) that showed an AmpC phenotype. In addition, the frequencies of the resistance genes were; OXA48 gene 85.2%, OXA199, 139 3.8%, OXA23 3.8%, OXA2 66.6%, OXA10 3.8%, OXA51 85.2% and OXA58 3.8%. The IMP27 gene was detected in 9 isolates (8.57%) and the IMP3.34 was detected in 11 isolates (10.47%). Other genes detected included; lasR (17.1%), lasB (18%) and lasA (26.6%). There was a significant relationship between virulence factors and the OX and IMP genes ($p{\leq}0.05$). Conclusion: The relationship between antibiotic resistance and virulence factors observed in this study could play an important role in outbreaks associated with P. aeruginosa infections.

• 생명과학회지
• /
• 제18권6호
• /
• pp.845-851
• /
• 2008

Bacillus sp. J105 strain으로부터 유도된 ${\beta}-lactamase$는 ammonium sulfate 침전, 이온 교환 칼럼 크로마토그래피, 겔 여과 등의 과정을 거쳐 SDS-PAGE에서 단일 band로 정제하였다. 정제된 효소의 분자량은 31 kDa이었으며 등전점은 7.35이었다. 효소반응의 최적 pH와 온도는 각각 5와 $40^{\circ}C$이었다. 정제 단백질의 총 아미노산 조성의 분석 결과, Gly과 Ala이 각각 14.1과 13.3 mole%로 가장 많은 아미노산 잔기를 차지하고 있었다. 정제 효소의 ampicillin을 기질로 하였을 때의 Km값은 1.33 mM이었고 Vmax값은 0.36 mM/ml이었다.

• 대한소아치과학회지
• /
• 제38권2호
• /
• pp.170-178
• /
• 2011

항생제 사용에 따라 구강내 세균들이 가지게 되는 내성의 발현이 문제가 될 수 있다. 어린이 치면세균막에서 치주질환의 원인균들과 흔히 사용하고 있는 항생제들에 대한 내성유전자의 출현율을 알아보고자 중합효소연쇄반응을 이용하여 조사하였다. 1. 치주질환 원인균의 출현율은 F. nucleatum 95.4%, T. forsythia 55.2% 이었으며, P. gingivalis 40.2%, A. actinomycetemcomitans 5.7%, T. denticola는 3.4% 순이었다. 2. 항생제 내성유전자의 출현율 조사에서 cephalosporin 분해효소인 cfxA는 100%에서 발견되었으며 ${\beta}$-lactam 분해효소인 $bla_{TEM}$과 tetracycline 내성유전자인 tet(M)도 100%의 출현율을 보였다. tet(Q)는 88.5%, ${\beta}$-lactam 분해효소인 $bla_{SHV}$는 29.9%, macrolide계 내성 ermF유전자는 87.4%, vancomycin 내성 vanA는 48.5%의 출현율을 보였다. Aminoglycoside에 대한 복합 내성을 보이는 aacA-aphD와 meticillin 내성유전자 mecA는 9.2%로 가장 낮은 출현율을 보였다. 3. 치주질환 원인균과 항생제 내성유전자와의 관련성 조사에서 T. forsythia와 $bla_{SHV}$간에 그리고 P. gingivalis와 vanA간 에 유의한 상관성이 있었다. 항생제 내성유전자 tet(Q)와 ermF (0.514)간에 중등도의 상관성을 나타내었으며, mecA와 vanA (0.25)간에 유의한 상관성을 나타내었다. 건강한 어린이들의 치면세균막에 다양한 치주질환 원인균들과 항생제 내성유전자들이 존재하며, 상호 관련성을 가지고 존재함을 보여주었다.

• 대한족부족관절학회지
• /
• 제13권2호
• /
• pp.146-149
• /
• 2009

Purpose: Foot infections are common complications in patients with diabetes. The patients are usually immune-compromised; therefore the pathogens could be resistant to narrow spectrum antibiotics. Those drugs, however, are categorized as specially managed antibiotics, and access are difficult without confirming of the pathogens. Our aim was to analyze the common pathogens in diabetic foot infection and figure out the proper antibiotics. Materials and Methods: We studied 68 patients treated with diabetic foot infection. The pathogens which caused the infection and their sensitivity to initial antibiotics were analyzed. We also investigated the change of the antibiotics after the confirming of the culture result and average time to get the result. Results: Among the 68 patients, 56 (82%) received cephalosporin and beta-lactam antibiotics. Only 12 (18%) who were confirmed the drug resistant pathogens from previous culture, were treated with broad spectrum antibiotics such as vancomycin and tazoperan. Average culture study time was 6 days. Methicillin-resistant staphylococcus aureus (MRSA) was cultured in 19 patients (28%), Methicillin-resistant coagulase negative staphylococcus (MRCNS) in 11 patietns (17%), pseudomonas in 11 patients (17%). Total 44 (65%) including 3 of other antibiotics resistant pathogen needed broad spectrum antibiotics. Thirty two patients (47%) were resistant to initial antibiotics.irt follow up culture, 2 MRSA and 2 MRCNS were found. The antibiotics resistant pathogens were confirmed in 48 (71%) patients at last. Conclusion: Diabetic patients with foot infection need proper antibiotics from initial treatment. The proper broad spectrum antibiotics should assigned to the patients from the first time without the confirming of the culture results.

• 한국미생물·생명공학회지
• /
• 제10권3호
• /
• pp.177-184
• /
• 1982

토양에서 분리, 선별한 Streptomyces 속의 한 균주가 생산하는 Penicillinase의 최적생산조건을 조사한 결과를 요약하면 다음과 같다. 탄소원으로서는 glucose, 실소원으로는 L-as-paragine이 가장 우수했으며 금속감중에서 Mn C $l_2$를 첨가했을때 효소생성을 37% 증가시켰다. Amino 산중에서 L-leucine이 본 효소생산을 약간 증가시켰으며 L-histidine L-methionine은 크게 저하시켰다. Riboflavine, i-inositol, hesperidine, niacinamide, biotin, DL-$\alpha$- lipoic acid, folic acid가 효소생산을 증가시켰으며 항생물질중에서 cephradine, cephalexin, ampicillin, cloxacillin의 첨가가 효소생성을 크게 증가시켰다. 본 효소생산의 최고 pH는 7.0이며 최적온도는 28$^{\circ}C$였다. 또 500$m\ell$ Erlenmeyer flask에서 175$m\ell$의 배지를 가하여 3 일간 배양했을 때 효소생성이 최고에 도달했다.

• 한국미생물·생명공학회지
• /
• 제46권2호
• /
• pp.162-170
• /
• 2018

Non-typhoidal Salmonella is one of the main pathogens causing food-borne illness in humans, with up to 20% of cases resulting from consumption of pork products. Over the gastroenteritis signs, multidrug resistant Salmonella has arisen. In this study, pan-susceptible phenotypic strains of Salmonella enterica serotype Weltevreden recovered from pig production chain in Chiang Mai, Thailand during 2012-2014 were chosen for analysis. The aim of this study was to use whole genome sequencing (WGS) data with an emphasis on antimicrobial resistance gene investigation to assess their pathogenic potential and genetic diversity determination based on whole genome Multilocus Sequence Typing (wgMLST) to expand epidemiological knowledge and to provide additional guidance for disease control. Analyis using ResFinder 3.0 for WGS database tracing found that one of pan-susceptible phenotypic strain carried five classes of resistance genes: aminoglycoside, beta-lactam, phenicol, sulfonamide, and tetracycline associated genes. Twenty four and 36 loci differences were detected by core genome Multilocus Sequence Typing (cgMLST) and pan genome Multilocus Sequence Typing (pgMLST), respectively, in two matching strains (44/13 vs A543057 and A543056 vs 204/13) initially assigned by conventional MLST and Pulsed-field Gel Electrophoresis (PFGE). One hundread percent discriminant ability can be achieved using the wgMLST technique. WGS is currently the ultimate molecular technique for various in-depth studies. As the findings stated above, a new of "gold standard typing method era" for routine works in genome study is being set.

• The Korean Journal of Physiology and Pharmacology
• /
• 제20권2호
• /
• pp.185-192
• /
• 2016

Ampicillin, a ${\beta}$-lactam antibiotic, dose-dependently protects neurons against ischemic brain injury. The present study was performed to investigate the neuroprotective mechanism of ampicillin in a mouse model of transient global forebrain ischemia. Male C57BL/6 mice were anesthetized with halothane and subjected to bilateral common carotid artery occlusion for 40 min. Before transient forebrain ischemia, ampicillin (200 mg/kg, intraperitoneally [i.p.]) or penicillin G (6,000 U/kg or 20,000 U/kg, i.p.) was administered daily for 5 days. The pretreatment with ampicillin but not with penicillin G significantly attenuated neuronal damage in the hippocampal CA1 subfield. Mechanistically, the increased activity of matrix metalloproteinases (MMPs) following forebrain ischemia was also attenuated by ampicillin treatment. In addition, the ampicillin treatment reversed increased immunoreactivities to glial fibrillary acidic protein and isolectin B4, markers of astrocytes and microglia, respectively. Furthermore, the ampicillin treatment significantly increased the level of glutamate transporter-1, and dihydrokainic acid (DHK, 10 mg/kg, i.p.), an inhibitor of glutamate transporter-1 (GLT-1), reversed the neuroprotective effect of ampicillin. Taken together, these data indicate that ampicillin provides neuroprotection against ischemia-reperfusion brain injury, possibly through inducing the GLT-1 protein and inhibiting the activity of MMP in the mouse hippocampus.

• 대한한방내과학회지
• /
• 제34권3호
• /
• pp.278-288
• /
• 2013

Objectives : Methicillin-resistant Staphylococcus aureus (MRSA) has a cephalosporin and beta-lactam antibiotic-resistant strains. MRSA is one of the major pathogens causing hospital infection and the isolation ratio of MRSA has gradually increased. Consequently, increased resistance to antibiotics is causing serious problems in the world. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases. Methods : The antibacterial activities of Ipyo-san were evaluated against 2 strains of MRSA and 1 standard Methicillin-susceptible staphylococcus aureus (MSSA) strain by using the disc diffusion method, minimal inhibitory concentrations (MIC) assay, colorimetric assay using MTT test, checkerboard dilution test and time-kill assay performed under dark. Results : The MIC of Ipyo-san water extract against S. aureus strains ranged from 1000 to $2,000{\mu}g/ml$, so we confirmed that it had a strong antibacterial effect. Also, the combinations of Ipyo-san water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. We suggest that Ipyo-san water extract against MRSA has antibacterial activity so it has potential as alternatives to antibiotic agents. For the combination test, we used Triton X-100 (TX) and DCCD for measurement of membrane permeability and inhibitor of ATPase. As a result, antimicrobial activity of Ipyo-san water extract was affected by the cell membrane. Conclusions : We suggest that the Ipyo-san water extract lead the treatment of bacterial infection to solve the resistance and remaining side-effect problems that are the major weak points of traditional antibiotics.