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Sample records for cephamycins

  1. Cephamycin inactivation due to enzymatic hydrolysis by beta-lactamase from Bacteroides fragilis.

    OpenAIRE

    Yotsuji, A; Minami, S; Kakizawa, H; Yasuda, T; Takai, A.; Saikawa, I; Inoue, M.; Mitsuhashi, S

    1985-01-01

    The susceptibility of 53 clinical isolates of Bacteroides fragilis to cephamycins was examined. Judging from the MICs for 50% of the strains tested, moxalactam was the most active, however, judging from the MICs for 90% of the strains tested, cefbuperazone was more effective than moxalactam. A correlation was observed between in vitro activity of benzylpenicillin and cephaloridine and beta-lactamase production. Inactivation due to enzymatic hydrolysis of cephamycins over a short time was not ...

  2. Evaluation of cephamycins as supplements to selective agar for detecting Campylobacter spp. in chicken carcass rinses.

    Science.gov (United States)

    Chon, Jung-Whan; Kim, Young-Ji; Kim, Hong-Seok; Kim, Dong-Hyeon; Kim, Hyunsook; Song, Kwang-Young; Sung, Kidon; Seo, Kun-Ho

    2016-04-16

    Although cefoperazone is the most commonly used antibiotic in Campylobacter-selective media, the distribution of cefoperazone-resistant bacteria such as extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli is increasing. Here we evaluated the potential of cephamycins for use as supplements to improve modified charcoal-cefoperazone-deoxycholate agar (mCCDA) by replacing cefoperazone with the same concentrations (32 mg/L) of cefotetan (modified charcoal-cefotetan-deoxycholate agar, mCCtDA) and cefoxitin (modified charcoal-cefoxitin-deoxycholate agar, mCCxDA). In chicken carcass rinse samples, the number of mCCDA plates detecting for Campylobacter (18/70, 26%) was significantly lower than that of mCCtDA (42/70, 60%) or mCCxDA plates (40/70, 57%). The number of mCCDA plates (70/70, 100%) that were contaminated with non-Campylobacter species was significantly higher than that of mCCtDA (20/70, 29%) or mCCxDA plates (21/70, 30%). The most common competing species identified using mCCDA was ESBL-producing E. coli, while Pseudomonas species frequently appeared on mCCtDA and mCCxDA.

  3. Production of clavulanic acid and cephamycin C by Streptomyces clavuligerus under different fed-batch conditions

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    C. Bellão

    2013-06-01

    Full Text Available The effect of carbon source and feeding conditions on the production of clavulanic acid (CA and cephamycin C (CephC by Streptomyces clavuligerus was investigated. In fed-batch experiments performed with glycerol feeding, production of CA exceeded that of CephC, and reached 1022 mg.L-1. Highest CephC production (566.5 mg.L-1 was obtained in fed-batch cultivation with glycerol feeding. In fed-batch experiments performed with starch feeding, the production of CephC was in general higher than that of CA. A dissociation index (DI was used to identify feeding conditions that favored production of CephC relative to CA. In all cultures with glycerol, DI values were less than unity, indicating higher production of CA compared to CephC. Conversely, in cultures fed with starch, the DI values obtained were greater than unity. However, no carbon source or feeding condition was able to completely dissociate the production of CA from that of CephC.

  4. Dissociation of cephamycin C and clavulanic acid biosynthesis by 1,3-diaminopropane in Streptomyces clavuligerus.

    Science.gov (United States)

    Leite, Carla A; Cavallieri, André P; Baptista, Amanda S; Araujo, Maria L G C

    2016-01-01

    Streptomyces clavuligerus produces simultaneously cephamycin C (CephC) and clavulanic acid (CA). Adding 1,3-diaminopropane to culture medium stimulates production of beta-lactam antibiotics. However, there are no studies on the influence of this diamine on coordinated production of CephC and CA. This study indicates that 1,3-diaminopropane can dissociate CephC and CA productions. Results indicated that low diamine concentrations (below 1.25 g l(-1)) in culture medium increased CA production by 200%, but not that of CephC. Conversely, CephC production increased by 300% when 10 g l(-1) 1,3-diaminopropane was added to culture medium. Addition of just L-lysine (18.3 g l(-1)) to culture medium increased both biocompounds. On the other hand, while L-lysine plus 7.5 g l(-1) 1,3-diaminopropane increased volumetric production of CephC by 1100%, its impact on CA production was insignificant. The combined results suggest that extracellular concentration of 1,3-diaminopropane may trigger the dissociation of CephC and CA biosynthesis in S. clavuligerus.

  5. Characterization of DNA-binding sequences for CcaR in the cephamycin-clavulanic acid supercluster of Streptomyces clavuligerus.

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    Santamarta, I; López-García, M T; Kurt, A; Nárdiz, N; Alvarez-Álvarez, R; Pérez-Redondo, R; Martín, J F; Liras, P

    2011-08-01

    RT-PCR analysis of the genes in the clavulanic acid cluster revealed three transcriptional polycistronic units that comprised the ceaS2-bls2-pah2-cas2, cyp-fd-orf12-orf13 and oppA2-orf16 genes, whereas oat2, car, oppA1, claR, orf14, gcaS and pbpA were expressed as monocistronic transcripts. Quantitative RT-PCR of Streptomyces clavuligerus ATCC 27064 and the mutant S. clavuligerus ccaR::aph showed that, in the mutant, there was a 1000- to 10,000-fold lower transcript level for the ceaS2 to cas2 polycistronic transcript that encoded CeaS2, the first enzyme of the clavulanic acid pathway that commits arginine to clavulanic acid biosynthesis. Smaller decreases in expression were observed in the ccaR mutant for other genes in the cluster. Two-dimensional electrophoresis and MALDI-TOF analysis confirmed the absence in the mutant strain of proteins CeaS2, Bls2, Pah2 and Car that are required for clavulanic acid biosynthesis, and CefF and IPNS that are required for cephamycin biosynthesis. Gel shift electrophoresis using recombinant r-CcaR protein showed that it bound to the ceaS2 and claR promoter regions in the clavulanic acid cluster, and to the lat, cefF, cefD-cmcI and ccaR promoter regions in the cephamycin C gene cluster. Footprinting experiments indicated that triple heptameric conserved sequences were protected by r-CcaR, and allowed identification of heptameric sequences as CcaR binding sites.

  6. Cefotetan, a new cephamycin: comparison of in vitro antimicrobial activity with other cephems, beta-lactamase stability, and preliminary recommendations for disk diffusion testing.

    OpenAIRE

    Ayers, L W; Jones, R N; Barry, A. L.; Thornsberry, C; Fuchs, P C; Gavan, T L; Gerlach, E H; Sommers, H M

    1982-01-01

    Cefotetan is a new, potent, 7 alpha-methoxy cephalosporin (cephamycin). The in vitro activity of cefotetan tested in a multiphasic, collaborative study against 12,260 consecutive clinical isolates and 448 selected isolates showed 93% of Enterobacteriaceae, 90% of methicillin-susceptible Staphylococcus aureus (broth dilution), 83% of Bacteroides fragilis, and 72% of non-enterococcal streptococci to be inhibited by less than or equal to 8 micrograms/ml. Beta-Lactamase-producing and -nonproducin...

  7. Transcriptomic analysis of Streptomyces clavuligerus ΔccaR::tsr: effects of the cephamycin C-clavulanic acid cluster regulator CcaR on global regulation.

    Science.gov (United States)

    Alvarez-Álvarez, R; Rodríguez-García, A; Santamarta, I; Pérez-Redondo, R; Prieto-Domínguez, A; Martínez-Burgo, Y; Liras, P

    2014-05-01

    Streptomyces clavuligerus ATCC 27064 and S. clavuligerus ΔccaR::tsr cultures were grown in asparagine-starch medium, and samples were taken in the exponential and stationary growth phases. Transcriptomic analysis showed that the expression of 186 genes was altered in the ccaR-deleted mutant. These genes belong to the cephamycin C gene cluster, clavulanic acid gene cluster, clavams, holomycin, differentiation, carbon, nitrogen, amino acids or phosphate metabolism and energy production. All the clavulanic acid biosynthesis genes showed Mc values in the order of -4.23. The blip gene-encoding a β-lactamase inhibitory protein was also controlled by the cephamycin C-clavulanic acid cluster regulator (Mc -2.54). The expression of the cephamycin C biosynthesis genes was greatly reduced in the mutant (Mc values up to -7.1), while the genes involved in putative β-lactam resistance were less affected (Mc average -0.88). Genes for holomycin biosynthesis were upregulated. In addition, the lack of clavulanic acid and cephamycin production negatively affected the expression of genes for the clavulanic acid precursor arginine and of miscellaneous genes involved in nitrogen metabolism (amtB, glnB, glnA3, glnA2, glnA1). The transcriptomic results were validated by quantative reverse transcription polymerase chain reaction and luciferase assay of luxAB-coupled promoters. Transcriptomic analysis of the homologous genes of S. coelicolor validated the results obtained for S. clavuligerus primary metabolism genes.

  8. CcaR is an autoregulatory protein that binds to the ccaR and cefD-cmcI promoters of the cephamycin C-clavulanic acid cluster in Streptomyces clavuligerus.

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    Santamarta, Irene; Rodríguez-García, Antonio; Pérez-Redondo, Rosario; Martín, Juan F; Liras, Paloma

    2002-06-01

    The putative regulatory CcaR protein, which is encoded in the beta-lactam supercluster of Streptomyces clavuligerus, has been partially purified by ammonium sulfate precipitation and heparin affinity chromatography. In addition, it was expressed in Escherichia coli, purified as a His-tagged recombinant protein (rCcaR), and used to raise anti-rCcaR antibodies. The partially purified CcaR protein from S. clavuligerus was able to bind DNA fragments containing the promoter regions of the ccaR gene itself and the bidirectional cefD-cmcI promoter region. In contrast, CcaR did not bind to DNA fragments with the promoter regions of other genes of the cephamycin-clavulanic acid supercluster including lat, blp, claR, car-cyp, and the unlinked argR gene. The DNA shifts obtained with CcaR were prevented by anti-rCcaR immunoglobulin G (IgG) antibodies but not by anti-rabbit IgG antibodies. ccaR and the bidirectional cefD-cmcI promoter region were fused to the xylE reporter gene and expressed in Streptomyces lividans and S. clavuligerus. These constructs produced low catechol dioxygenase activity in the absence of CcaR; activity was increased 1.7- to 4.6-fold in cultures expressing CcaR. Amplification of the ccaR promoter region lacking its coding sequence in a high-copy-number plasmid in S. clavuligerus ATCC 27064 resulted in a reduced production of cephamycin C and clavulanic acid, by 12 to 20% and 40 to 60%, respectively, due to titration of the CcaR regulator. These findings confirm that CcaR is a positively acting autoregulatory protein able to bind to its own promoter as well as to the cefD-cmcI bidirectional promoter region.

  9. Ácido clavulânico e cefamicina c: uma perspectiva da biossíntese, processos de isolamento e mecanismo de ação Clavulanic acid and cephamicin c: a perspective of the biosynthesis, isolation and action mechanism

    Directory of Open Access Journals (Sweden)

    Jaine H. H. Luiz de Oliveira

    2009-01-01

    Full Text Available The present article reviews different aspects of the chemistry of two widely used β-lactam antibiotics Clavulanic Acid and Cephamycin C. The article discusses important details of the biosynthesis of these compounds, their action mechanism and, principally, the methods employed in their isolation and purification, in accordance with the available literature. Despite the large quantity of available articles and patents concerning β-lactam antibiotics, those which describe the isolation and purification of Clavulanic Acid and Cephamycin C are rare. Overall, the intention of this article is to discuss the up-to-date scientific research related to the compounds under review.

  10. GenBank blastx search result: AK058791 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK058791 001-002-F06 S55763.1 cephamycin gene cluster: cefD=isopenicillin N epimerase, cefE=deacetoxycephalo...sporin C synthase [Nocardia lactamdurans, Genomic, 2169 nt].|BCT BCT 4e-15 +3 ...

  11. Drug: D01736 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D01736 Drug Cefbuperazone sodium (JP16); CBPZ; Keiperazon (TN) C22H28N9O9S2. Na 649...S J01DC Second-generation cephalosporins J01DC13 Cefbuperazone D01736 Cefbuperazone sodium (JP16) Antiinfect...ing proteins inhibitor Cephems - Cephamycins Cefbuperazone [ATC:J01DC13] D01736 Cefbuperazone sodium (JP16)

  12. Animal and Human Multidrug-Resistant, Cephalosporin-Resistant Salmonella Isolates Expressing a Plasmid-Mediated CMY-2 AmpC β-Lactamase

    OpenAIRE

    Winokur, P. L.; Brueggemann, A.; DeSalvo, D. L.; Hoffmann, L.; Apley, M. D.; Uhlenhopp, E. K.; Pfaller, M A; Doern, G. V.

    2000-01-01

    Salmonella spp. are important food-borne pathogens that are demonstrating increasing antimicrobial resistance rates in isolates obtained from food animals and humans. In this study, 10 multidrug-resistant, cephalosporin-resistant Salmonella isolates from bovine, porcine, and human sources from a single geographic region were identified. All isolates demonstrated resistance to cephamycins and extended-spectrum cephalosporins as well as tetracycline, chloramphenicol, streptomycin, and sulfisoxa...

  13. Utilization of ornithine and arginine as specific precursors of clavulanic acid.

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    Romero, J; Liras, P; Martín, J F

    1986-01-01

    Ornithine and arginine (5 to 20 mM), but not glutamic acid or proline, exerted a concentration-dependent stimulatory effect on the biosynthesis of clavulanic acid in both resting-cell cultures and long-term fermentations of Streptomyces clavuligerus. Ornithine strongly inhibited cephamycin biosynthesis in the same strain. [1-14C]-, [5-14C]-, or [U-14 C] ornithine was efficiently incorporated into clavulanic acid, whereas the incorporation of uniformly labeled glutamic acid was very poor. [U-1...

  14. In Vitro Activities of Cefminox against Anaerobic Bacteria Compared with Those of Nine Other Compounds

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    Hoellman, Dianne B.; Spangler, Sheila K.; Jacobs, Michael R.; Appelbaum, Peter C.

    1998-01-01

    The agar dilution MIC method was used to test the activity of cefminox, a β-lactamase-stable cephamycin, compared with those of cefoxitin, cefotetan, moxalactam, ceftizoxime, cefotiam, cefamandole, cefoperazone, clindamycin, and metronidazole against 357 anaerobes. Overall, cefminox was the most active β-lactam, with an MIC at which 50% of isolates are inhibited (MIC50) of 1.0 μg/ml and an MIC90 of 16.0 μg/ml. Other β-lactams were less active, with respective MIC50s and MIC90s of 2.0 and 64.0...

  15. Drug: D03423 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D03423 Drug Cefbuperazone (USAN/INN); CBPZ C22H29N9O9S2 627.153 627.6506 D03423.gif... cephalosporins J01DC13 Cefbuperazone D03423 Cefbuperazone (USAN/INN) Antiinfectives [BR:br08307] Antibacter...ials Cell wall biosynthesis inhibitor Penicillin binding proteins inhibitor Cephems - Cephamycins Cefb...uperazone [ATC:J01DC13] D03423 Cefbuperazone (USAN/INN) CAS: 76610-84-9 PubChem: 173975

  16. Evidence for Transfer of CMY-2 AmpC β-Lactamase Plasmids between Escherichia coli and Salmonella Isolates from Food Animals and Humans

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    Winokur, P. L.; Vonstein, D. L.; Hoffman, L J; Uhlenhopp, E. K.; Doern, G. V.

    2001-01-01

    Escherichia coli is an important pathogen that shows increasing antimicrobial resistance in isolates from both animals and humans. Our laboratory recently described Salmonella isolates from food animals and humans that expressed an identical plasmid-mediated, AmpC-like β-lactamase, CMY-2. In the present study, 59 of 377 E. coli isolates from cattle and swine (15.6%) and 6 of 1,017 (0.6%) isolates of human E. coli from the same geographic region were resistant to both cephamycins and extended-...

  17. Resistance patterns to beta-lactams and quinolones in clinical isolates of bacteria from Cuban hospitals.

    Science.gov (United States)

    Gonzáles, I; Niebla, A; Vallin, C

    1995-01-01

    The resistance patterns to 26 beta-lactams and 8 quinolones of clinical isolates from Cuban hospitals were evaluated using the disk susceptibility test, according to the NCCLS guidelines (1992). The genera studied were Escherichia sp (320), Enterobacter sp (10), Klebsiella sp (90), Proteus sp (10), Pseudomonas sp (90), Serratia sp (20), and Staphylococcus sp (80). Higher resistance to beta-lactams was observed in the genera Pseudomonas, Escherichia and Klebsiella. For fluoroquinolones we found no significant resistance, with the exception of the genus Klebsiella. The most effective antibiotics were cephalosporins of the second and third generations, fluoroquinolones, and non-classical beta-lactams (cephamycins, moxalactam and monobactams). On the contrary, a pronounced resistance was found to penicillin, oxacillin, ticarcillin, ampicillin, methicillin, nalidixic acid and cinoxacin. These resistance patterns correspond to the high consumption of these antibiotics throughout the country.

  18. Utilization of ornithine and arginine as specific precursors of clavulanic acid.

    Science.gov (United States)

    Romero, J; Liras, P; Martín, J F

    1986-01-01

    Ornithine and arginine (5 to 20 mM), but not glutamic acid or proline, exerted a concentration-dependent stimulatory effect on the biosynthesis of clavulanic acid in both resting-cell cultures and long-term fermentations of Streptomyces clavuligerus. Ornithine strongly inhibited cephamycin biosynthesis in the same strain. [1-14C]-, [5-14C]-, or [U-14 C] ornithine was efficiently incorporated into clavulanic acid, whereas the incorporation of uniformly labeled glutamic acid was very poor. [U-14C] citrulline were not incorporated at all. Mutant nca-1, a strain that is blocked in clavulanic acid biosynthesis, did not incorporate arginine into clavulanic acid. S. clavuligerus showed arginase activity, converting arginine into ornithine, but not amidinotransferase activity. Both arginase activity and clavulanic acid formation were enhanced simultaneously by supplementing the production medium with 10 mM arginine. PMID:2877616

  19. In vitro activities and detection performances of cefmetazole and flomoxef for extended-spectrum β-lactamase and plasmid-mediated AmpC β-lactamase-producing Enterobacteriaceae.

    Science.gov (United States)

    Matsumura, Yasufumi; Yamamoto, Masaki; Nagao, Miki; Tanaka, Michio; Takakura, Shunji; Ichiyama, Satoshi

    2016-04-01

    To investigate the in vitro activities of cephamycins (cefmetazole and flomoxef) for extended-spectrum β-lactamase (ESBL)- and plasmid-mediated AmpC β-lactamase (pAmpC)-producing Enterobacteriaceae, a total of 574 third-generation cephalosporin-resistant clinical isolates were collected at a Japanese multicenter study. PCR and sequencing identified 394 isolates with only ESBL genes, 63 isolates with only pAmpC genes, and 6 isolates with both ESBL and pAmpC genes. blaCTX-M types predominated 95.5% of the ESBL genes, and blaCMY-2 predominated 91.3% of the pAmpC genes. The MIC50/90 values of cefmetazole and flomoxef were ≤ 1/4 and ≤ 1/≤ 1 μg/mL for isolates with only ESBL genes, respectively, and 16/>16 and 8/16 μg/mL for isolates with only pAmpC genes, respectively. Flomoxef ≥ 4 μg/mL had the best screening performance for the detection of isolates with pAmpC genes. Flomoxef had better in vitro activities against ESBL-producing Enterobacteriaceae and provided a clearer distinction between ESBL and pAmpC-producing Enterobacteriaceae compared to cefmetazole. PMID:26782634

  20. Molecular characterization of extended-spectrum beta-lactamases and its correlation with clinical laboratory standards institute interpretive criteria for disk diffusion susceptibility testing in enterobacteriaceae isolates in Thaialnd.

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    Tangkoskul, Teerawit; Tiengrim, Surapee; Onsomang, Supiluck; Pati, Naratchaphan; Aswapokee, Nalinee; Thamlikitkul, Visanu; Chayakulkeeree, Methee

    2012-11-01

    We performed extended-spectrum beta-lactamase (ESBL) phenotypic testing and molecular characterization of three ESBL genes (TEM, SHV and CTX-M) and susceptibility testing by Clinical Laboratory Standards Institute (CLSI) disk diffusion method against three cephalosporins (ceftriaxone, ceftazidime, cefepime) and a cephamycin (cefoxitin) among 128 Thai Escherichia coli and 84 Thai Klebsiella pneumoniae clinical isolates. ESBL production was discovered in 62% of E. coli and 43% of K. pneumoniae isolates. All isolates susceptible to ceftriaxone were ESBL-negative. Nearly all isolates non-susceptible to ceftriaxone, ceftazidime and cefepime produced ESBL; the presence of CTX-M genes in the isolates correlated with a ceftriaxone non-susceptible phenotype. Thirty-nine of 83 isolates (47%) of ceftazidime-susceptible E. coli and 50 of 99 isolates (50.5%) of cefepime-susceptible E. coli were ESBL-producing. SHV-type beta-lactamase genes were more prevalent among K. pneumoniae than E. coli isolates. CTX-M was the major ESBL gene harbored by ESBL-producers in both E. coli and K. pneumoniae isolates. Non-CTX-M ESBL-producers were found only among K. pneumoniae isolates. This study reveals an increase in ESBL-producing Enterobacteriaceae among Thai isolates and demonstrates gaps in the current CLSI disk diffusion susceptibility guidelines; it indicates the results of ceftazidime and cefepime disk diffusion susceptibility testing using CLSI criteria should be interpreted with caution.

  1. The Mechanisms of Catalysis by Metallo -Lactamases

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    Michael I. Page

    2008-01-01

    Full Text Available Class B -lactamases or metallo--lactamases (MBLs require zinc ions to catalyse the hydrolysis of -lactam antibiotics such as penicillins, cephalosporins, carbapenems, and cephamycins. There are no clinically useful inhibitors against MBLs which are responsible for the resistance of some bacteria to antibiotics. There are two metal-ion binding sites that have different zinc ligands but the exact roles of the metal-ion remain controversial, and distinguishing between their relative importance is complex. The metal-ion can act as a Lewis acid by co-ordination to the -lactam carbonyl oxygen to facilitate nucleophilic attack and stabilise the negative charge developed on this oxygen in the tetrahedral intermediate anion. The metal-ion also lowers the pKa of the directly co-ordinated water molecule so that the metal-bound hydroxide ion is a better nucleophile than water and is used to attack the -lactam carbonyl carbon. An intrinsic property of binuclear metallo hydrolytic enzymes that depend on a metal-bound water both as the attacking nucleophile and as a ligand for the second metal-ion is that this water molecule, which is consumed during hydrolysis of the substrate, has to be replaced to maintain the catalytic cycle. With MBL this is reflected in some unusual kinetic profiles.

  2. TO CORRELATE DOUBLE DISC SYNERGY TEST (DDST AND ETEST RESULTS FOR ESBL DETECTION IN ECOLI & KLEBSIELLA PNEUMONIAE ISOLATES

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    Rashmi

    2015-08-01

    Full Text Available Resistant to antimicrobial agents in microbes is a growing phenomenon worldwide. 1 β lactamase production is the most common mechanism of bacterial resistance to β lactam antibiotics. 2 Extended spectrum beta lactamases (ESBL that mediate resistance to oxyimino cephalosporins such as cefotaxime, ceftazidime and aztreonam are now observed in all species of Enterobacteriaceae. ESBL are capable of efficiently hydrolyzing penicillins, narro w spectrum cephalosporins, many extended spectrum cephalosporins, the oxyimino group containing cephalosporins ( C efotaxime, ceftazidime and monobactams ( A ztreonam, but not carbapenems and cephamycins. 3 ESBL producing Ecoli and Klebsiella pneumoniae are important pathogen in nosocomial infections and multidrug resistant out breaks. This study was conducted to correlate results of Double Disc Synergy Test (DDST and E test for ESBL detection in E coli and Klebsiella pneumoniae isolate by doing the double d isc synergy test (DDST by using cefotaxime and augmemtin discs. E test was used to determine the MIC for cefotaxime and ceftazidime of these isolates. Out of 98 ESBL isolates detected by DDST, 96 isolates were positive by E test. 02 isolates were indeterminable by E test. About 95% ESBL producing E coli and Klebsiella pneumoniae had MIC >1ug/ml for cefotaxime. The MIC of about 85% ESBL producing E coli and Klebsiella pneumonia was >4ug/ml for ceftazidime.

  3. Clavulanic acid production by Streptomyces clavuligerus: biogenesis, regulation and strain improvement.

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    Paradkar, Ashish

    2013-07-01

    Clavulanic acid (CA) is a potent β-lactamase inhibitor produced by Streptomyces clavuligerus and has been successfully used in combination with β-lactam antibiotics (for example, Augmentin) to treat infections caused by β-lactamase-producing pathogens. Since the discovery of CA in the late 1970s, significant information has accumulated on its biosynthesis, and regarding molecular mechanisms involved in the regulation of its production. Notably, the genes directing CA biosynthesis are clustered along with the genes responsible for the biosynthesis of the β-lactam antibiotic, cephamycin C, and co-regulated, which makes this organism unique in that the production of an antibiotic and production of a small molecule to protect the antibiotic from its enzymatic degradation are controlled by shared mechanisms. Traditionally, the industrial strain improvement programs have relied significantly on random mutagenesis and selection approach. However, the recent availability of the genome sequence of S. clavuligerus along with the capability to build metabolic models, and ability to engineer the organism by directed approaches, has created exciting opportunities to improve strain productivity more efficiently. This review will include focus mainly on the gene organization of the CA biosynthetic genes, regulatory mechanisms that affect its production, and will include perspectives on improving strain productivity.

  4. 临床分离大肠埃希菌的耐药性分析%ANALYSIS OF THE DRUG RESISTANCE OF THE CLINICAL ISOLATED ESCHERICHI COLI

    Institute of Scientific and Technical Information of China (English)

    包东武; 刘荣志

    2011-01-01

    [目的]探讨临床分离大肠埃希菌对常用抗生素的耐药性和不同标本中大肠埃希菌的耐药性差异,为临床治疗提供依据.[方法]用VITEK32型全自动细菌分析系统对我院2007年元月~2009年7月临床分离的395株大肠埃希菌进行鉴定,药敏试验采用K-B法,判断标准按NCCLS2006年版进行.[结果]大肠埃希菌对亚胺培南和头孢哌酮/舒巴坦的耐药率分别为2.5%和0;对头孢3代和4代杭生素、头霉素类、氟曲南、阿米卡星、呋喃妥因、哌拉西林/三唑巴坦的耐药率为9.1%~21.5%;对青霉素类、喹诺酮类、磺胺类的耐药率为62.0%~83.5%;痰标本中大肠埃希菌的耐药率明显高于血液和尿液及其他标本的分离株.[结论]大肠埃希菌对青霉素类、喹诺酮类、磺胺类的耐药率较高;对头孢3代和4代抗生素、头霉素类、氨曲南、阿米卡星、呋喃妥因和哌拉西林/三唑巴坦的耐药率较低;目前对亚胺培南和头孢哌酮/舒巴坦敏感;不同标本中大肠埃希菌对同种抗生素的耐药性存在着差异.%[Objective] To understand drug tolerance of escherichina coli in common antibiotic and the difference of drug tolerance in different samples, and to select drugs for clinical reference. [Methods] 395 clinical separate strains escherichia coli and drug tolerance in our hospital from Jan2007 to July 2009 were identified and detected. Drug sensitive experiment was performed by (K- B) method, distinguished standard according to NCCLS 2006. [Results] Drug tolerant rate of escherichia coli in cefoperazone/sulbactam and imipenem were 2.5% and 0, respectively. The rates of cephaloglycin, cephalexin, Cephamycin, aztreonam, amikacin, nitrofurantoin and piperacillim were at the range of 9.1%-21.5%; The rates of penicillins, Quinovic - ketone sulfonamides were at the range of 62.0%-83.5%; Drug tolerant rate of escherichia coli in sputum was higher than that in blood, urine and other samples separate

  5. Clinical and microbiologic characteristics of adult patients with recurrent bacteraemia caused by extended-spectrum β-lactamase-producing Escherichia coli or Klebsiella pneumoniae.

    Science.gov (United States)

    Lee, C-H; Su, L-H; Chen, F-J; Tang, Y-F; Chien, C-C; Liu, J-W

    2015-12-01

    The characteristics of patients with recurrent bacteraemia caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli or Klebsiella pneumoniae (EK) are rarely described. Flomoxef belongs to the cephamycins group and demonstrates in vitro activity against ESBL-producing organisms. Whether flomoxef may be used for the treatment of such infections remains controversial. This retrospective case-control study enrolled adult patients who had bacteraemia caused by ESBL-EK during 2005-2011. Case patients were those who had more than one episode of ESBL-EK bacteraemia. Controls were those who were matched for age and interval time of blood sampling and had only one episode of ESBL-EK bacteraemia with subsequent bacteraemia episodes caused by other non-ESBL-EK bacteria. Pulsed-field gel electrophoresis and microbiologic profiles of the initial and subsequent ESBL-EK isolates were analysed. During the study period, 424 patients were found to have at least one positive blood culture after the first ESBL-EK bacteraemia episode, and 67 (15.8%) had a second episode of ESBL-EK bacteraemia. Bacteraemia resulting from vascular catheter-related infection (odds ratio, 3.24; 95% confidence interval, 1.31-8.05), and definitive therapy with flomoxef (odds ratio, 2.99; 95% confidence interval, 1.10-8.15) were both independent risk factors for the recurrence. Among the 56 patients with available ESBL-EK isolates for analysis, 38 (67.8%) were infected by genetically similar strains. In three of these 38 recurrent ESBL-EK bacteraemia cases caused by an identical strain, the minimum inhibitory concentrations of carbapenem for the subsequent K. pneumoniae isolates were fourfold or higher than the initial isolates. Recurrent bacteraemia was not uncommon in our patients with ESBL-EK bacteraemia, and most of the episodes were caused by identical strains.

  6. Determination of thermodynamic parameters of benzylpenicillin hydrolysis by metallo-β-lactamase CcrA from Bacteroides fragilis

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Le; Zhou, Li-Sheng; Liu, Cheng-Cheng; Shi, Ying; Zhou, Ya-Jun [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an 710069 (China); Yang, Ke-Wu, E-mail: kwyang@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an 710069 (China)

    2013-03-20

    Highlights: ► First report the thermokinetic parameters of benzylpenicillin hydrolysis with CcrA. ► The hydrolysis is a spontaneous and exothermic reaction with order of 1.4. ► Summarized that CcrA prefer to hydrolyze penicillins among β-lactam antibiotics. - Abstract: One of the most common way that bacteria become resistant to antibiotics is by the production of metallo-β-lactamases (MβLs) to hydrolyze the β-lactam-containing antibiotics. In this paper, the thermodynamic parameters of benzylpenicillin hydrolysis with B1 subclasses MβL CcrA (carbapenem and cephamycin resistance) from Bacteroides fragilis were determined by microcalorimetry. The activation free energy ΔG{sub ≠}{sup θ} is 87.90 ± 0.03, 88.99 ± 0.01, 89.93 ± 0.04 and 90.93 ± 0.05 kJ mol{sup −1} at 293.15, 298.15, 303.15 and 308.15 K, activation enthalpy ΔH{sub ≠}{sup θ} is 29.21 ± 0.03 kJ mol{sup −1}, activation entropy ΔS{sub ≠}{sup θ} is −200.34 ± 0.08 J mol{sup −1} K{sup −1}, the reaction order is 1.4, and the apparent activation energy E is 31.71 kJ mol{sup −1}. The thermodynamic characterization indicated that CcrA prefer to hydrolyze penicillins among three kinds of β-lactam-containing antibiotics.

  7. OXA-18, a class D clavulanic acid-inhibited extended-spectrum beta-lactamase from Pseudomonas aeruginosa.

    Science.gov (United States)

    Philippon, L N; Naas, T; Bouthors, A T; Barakett, V; Nordmann, P

    1997-01-01

    Clinical isolate Pseudomonas aeruginosa Mus showed resistance both to extended-spectrum cephalosporins and to aztreonam. We detected a typical double-disk synergy image when ceftazidime or aztreonam was placed next to a clavulanic acid disk on an agar plate. This resistance phenotype suggested the presence of an extended-spectrum beta-lactamase. Isoelectric focusing revealed that this strain produced three beta-lactamases, of pI 5.5, 7.4, and 8.2. A 2.6-kb Sau3A fragment encoding the extended-spectrum beta-lactamase of pI 5.5 was cloned from P. aeruginosa Mus genomic DNA. This enzyme, named OXA-18, had a relative molecular mass of 30.6 kDa. OXA-18 has a broad substrate profile, hydrolyzing amoxicillin, ticarcillin, cephalothin, ceftazidime, cefotaxime, and aztreonam, but not imipenem or cephamycins. Its activity was totally inhibited by clavulanic acid at 2 microg/ml. Hydrolysis constants of OXA-18 (Vmax, Km) confirmed the MIC results. Cloxacillin and oxacillin hydrolysis was noticeable with the partially purified OXA-18. The blaOXA-18 gene encodes a 275-amino-acid protein which has weak identity with all class D beta-lactamases except OXA-9 and OXA-12 (45 and 42% amino acid identity, respectively). OXA-18 is likely to be chromosomally encoded since no plasmid was found in the strain and because attempts to transfer the resistance marker failed. OXA-18 is peculiar since it is a class D beta-lactamase which confers high resistance to extended-spectrum cephalosporins and seems to have unique hydrolytic properties among non-class A enzymes. PMID:9333046

  8. In vitro activities of cefminox against anaerobic bacteria compared with those of nine other compounds.

    Science.gov (United States)

    Hoellman, D B; Spangler, S K; Jacobs, M R; Appelbaum, P C

    1998-03-01

    The agar dilution MIC method was used to test the activity of cefminox, a beta-lactamase-stable cephamycin, compared with those of cefoxitin, cefotetan, moxalactam, ceftizoxime, cefotiam, cefamandole, cefoperazone, clindamycin, and metronidazole against 357 anaerobes. Overall, cefminox was the most active beta-lactam, with an MIC at which 50% of isolates are inhibited (MIC50) of 1.0 microg/ml and an MIC90 of 16.0 microg/ml. Other beta-lactams were less active, with respective MIC50s and MIC90s of 2.0 and 64.0 microg/ml for cefoxitin, 2.0 and 128.0 microg/ml for cefotetan, 2.0 and 64.0 microg/ml for moxalactam, 4.0 and > 128.0 microg/ml for ceftizoxime, 16.0 and > 128.0 microg/ml for cefotiam, 8.0 and >128.0 microg/ml for cefamandole, and 4.0 and 128.0 microg/ml for cefoperazone. The clindamycin MIC50 and MIC90 were 0.5 and 8.0 microg/ml, respectively, and the metronidazole MIC50 and MIC90 were 1.0 and 4.0 microg/ml, respectively. Cefminox was especially active against Bacteroides fragilis (MIC90, 2.0 microg/ml), Bacteroides thetaiotaomicron (MIC90, 4.0 microg/ml), fusobacteria (MIC90, 1.0 microg/ml), peptostreptococci (MIC90, 2.0 microg/ml), and clostridia, including Clostridium difficile (MIC90, 2.0 microg/ml). Time-kill studies performed with six representative anaerobic species revealed that at the MIC all compounds except ceftizoxime were bactericidal (99.9% killing) against all strains after 48 h. At 24 h, only cefminox and cefoxitin at 4x the MIC and cefoperazone at 8x the MIC were bactericidal against all strains. After 12 h, at the MIC all compounds except moxalactam, ceftizoxime, cefotiam, cefamandole, clindamycin, and metronidazole gave 90% killing of all strains. After 3 h, cefminox at 2 x the MIC produced the most rapid effect, with 90% killing of all strains. PMID:9517922

  9. Analysis on drug resistance in Gram-negative bacilli producing AmpC enzyme%医院感染革兰阴性杆菌产AmpC酶状况及耐药性检测分析

    Institute of Scientific and Technical Information of China (English)

    李文波; 刘琼; 卢青云; 高武; 刘丽华; 王沛; 张玉娟

    2012-01-01

    Objective To investigate the nosocomial infection status and drug resistance of Gram-negative bacilli producing ceph-alosporinaseC AmpC enzyme). Methods Strains producing AmpC lactamases were detected by three-dimensional extract test. Drug susceptibility was determined by K - B disk diffusions method. Results The overall incidence rate of strains positive with AmpC lactamases was 18. 4% (109/331). The susceptibility rate of AmpC enzyme positive strains to third-generation cephalosporins, cephamycins,monobactam and antibiotics combined with inhibitors decreased,and relatively lower to Impenem,Cefepime and Ami-kacin, with resistace rate of (2/61) ,44. 26% (27/61) and 31. 1% (19/61) respectively. Resistance rates of AmpC enzyme positive strains were obviously greater than those of negative strains. Conclusion Drug resistance of Gram-negative bacilli might be associated with AmpC enzyme. Imipenem and forth-generation cephalosporins could be considered firstly for treatment of infection caused by AmpC enzyme positive Gram-negative bacilli.%目的 探讨产头孢菌素酶(AmpC酶)革兰阴性杆菌医院内感染现状及对药物敏感性的影响.方法 对临床标本进行分离鉴定,采用K-B法对常规药物进行耐药性检测,采用美国国家临床实验室标准化委员会(NCCLS)推荐的三维法检测AmpC酶.结果 在331株革兰阴性杆菌中检出产AmpC酶109株,产酶率为18.4%,产酶菌株对第3代头孢菌素、头霉素类、环丙沙星及含酶抑制剂复合物药物敏感率下降明显,对亚胺培南、头孢吡肟、丁胺卡那耐药率较低,分别为3.28%(2/61)、44.26%(27/61)、31.1%(19/61),产酶菌株对抗菌药物的耐药率明显高于非产酶菌株.结论 革兰阴性杆菌耐药与产AmpC酶有关,治疗该菌感染应选用亚胺培南、第4代头孢菌素等.

  10. Analysis of the use of antimicrobial agents and the monitoring of bacterial resistance%2011-2013年我院抗菌药物使用与细菌耐药性监测的分析

    Institute of Scientific and Technical Information of China (English)

    宋桂芳; 王韵

    2015-01-01

    Objective:To analyze relevance between the DDDs of antimicrobial agents and the drug resistance of common clinical pathogens in our hospital during 2011-2013 so as to provide a basis for guiding rational drug use. Methods:The number of consumption of antimicrobial agents and the incidence of major drug resistant pathogens were statistically analyzed and the related data were compared. Results:The DDDs of the third generation of cephalosporins, cephamycins, carbapenems and macrolides showed an upward trend, and the rates of drug resistance of main bacteria such as Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa Bowman/hemolytic Acinetobacter, Staphylococcus aureus and so on also showed an increasing trend. Conclusion:The DDDs of antimicrobial agents and bacterial resistance are closely related and therefore the management of antimicrobial agents should be further strengthened and improved and great attention should be paid to the monitoring of bacterial resistance.%目的:分析我院抗菌药物用药频度及与临床常见致病菌耐药情况的关联性,为指导合理用药提供依据。方法:对本院2011-2013年抗菌药物消耗数量进行统计分析,并对主要致病菌的耐药率进行统计,分析比较相关数据。结果:三代头孢菌素、头霉素类、碳青霉烯类和大环内酯类的DDDs呈上升趋势,主要致病菌大肠埃希氏菌、肺炎克雷伯氏菌、铜绿假单胞菌、鲍曼/溶血不动杆菌、金黄色葡萄球菌等的耐药率也呈逐年上升的趋势。结论:抗菌药物的DDDs对细菌耐药率关联性高,医院需要进一步加强和完善抗菌药物的管理,对细菌耐药率监测应高度重视。

  11. Characterization of VIM-2, a carbapenem-hydrolyzing metallo-beta-lactamase and its plasmid- and integron-borne gene from a Pseudomonas aeruginosa clinical isolate in France.

    Science.gov (United States)

    Poirel, L; Naas, T; Nicolas, D; Collet, L; Bellais, S; Cavallo, J D; Nordmann, P

    2000-04-01

    Pseudomonas aeruginosa COL-1 was identified in a blood culture of a 39-year-old-woman treated with imipenem in Marseilles, France, in 1996. This strain was resistant to beta-lactams, including ureidopenicillins, ticarcillin-clavulanic acid, cefepime, ceftazidime, imipenem, and meropenem, but remained susceptible to the monobactam aztreonam. The carbapenem-hydrolyzing beta-lactamase gene of P. aeruginosa COL-1 was cloned, sequenced, and expressed in Escherichia coli DH10B. The deduced 266-amino-acid protein was an Ambler class B beta-lactamase, with amino acid identities of 32% with B-II from Bacillus cereus; 31% with IMP-1 from several gram-negative rods in Japan, including P. aeruginosa; 27% with CcrA from Bacteroides fragilis; 24% with BlaB from Chryseobacterium meningosepticum; 24% with IND-1 from Chryseobacterium indologenes; 21% with CphA-1 from Aeromonas hydrophila; and 11% with L-1 from Stenotrophomonas maltophilia. It was most closely related to VIM-1 beta-lactamase recently reported from Italian P. aeruginosa clinical isolates (90% amino acid identity). Purified VIM-2 beta-lactamase had a pI of 5.6, a relative molecular mass of 29.7 kDa, and a broad substrate hydrolysis range, including penicillins, cephalosporins, cephamycins, oxacephamycins, and carbapenems, but not monobactams. As a metallo-beta-lactamase, its activity was zinc dependent and inhibited by EDTA (50% inhibitory concentration, 50 microM). VIM-2 conferred a resistance pattern to beta-lactams in E. coli DH10B that paralleled its in vitro hydrolytic properties, except for susceptibility to ureidopenicillins, carbapenems, and cefepime. bla(VIM-2) was located on a ca. 45-kb plasmid that in addition conferred resistance to sulfamides and that was not self-transmissible either from P. aeruginosa to E. coli or from E. coli to E. coli. bla(VIM-2) was the only gene cassette located within the variable region of a novel class 1 integron, In56, that was weakly related to the bla(VIM-1)-containing

  12. Natural Variants of the KPC-2 Carbapenemase have Evolved Increased Catalytic Efficiency for Ceftazidime Hydrolysis at the Cost of Enzyme Stability.

    Directory of Open Access Journals (Sweden)

    Shrenik C Mehta

    2015-06-01

    Full Text Available The spread of β-lactamases that hydrolyze penicillins, cephalosporins and carbapenems among Gram-negative bacteria has limited options for treating bacterial infections. Initially, Klebsiella pneumoniae carbapenemase-2 (KPC-2 emerged as a widespread carbapenem hydrolyzing β-lactamase that also hydrolyzes penicillins and cephalosporins but not cephamycins and ceftazidime. In recent years, single and double amino acid substitution variants of KPC-2 have emerged among clinical isolates that show increased resistance to ceftazidime. Because it confers multi-drug resistance, KPC β-lactamase is a threat to public health. In this study, the evolution of KPC-2 function was determined in nine clinically isolated variants by examining the effects of the substitutions on enzyme kinetic parameters, protein stability and antibiotic resistance profile. The results indicate that the amino acid substitutions associated with KPC-2 natural variants lead to increased catalytic efficiency for ceftazidime hydrolysis and a consequent increase in ceftazidime resistance. Single substitutions lead to modest increases in catalytic activity while the double mutants exhibit significantly increased ceftazidime hydrolysis and resistance levels. The P104R, V240G and H274Y substitutions in single and double mutant combinations lead to the largest increases in ceftazidime hydrolysis and resistance. Molecular modeling suggests that the P104R and H274Y mutations could facilitate ceftazidime hydrolysis through increased hydrogen bonding interactions with the substrate while the V240G substitution may enhance backbone flexibility so that larger substrates might be accommodated in the active site. Additionally, we observed a strong correlation between gain of catalytic function for ceftazidime hydrolysis and loss of enzyme stability, which is in agreement with the 'stability-function tradeoff' phenomenon. The high Tm of KPC-2 (66.5°C provides an evolutionary advantage as

  13. 72株非伤寒沙门菌药敏分析及其所致儿童肠炎的临床特点%Drug sensitivity analysis of 72 non-typhoidal Salmonella and clinical characteristics of the caused enteritis in children

    Institute of Scientific and Technical Information of China (English)

    谢广清; 龙晓玲; 梁展图; 张泉山; 付四毛

    2011-01-01

    The present paper aims to explore drug resistance of 72 non-typhoidal Salmonella isolates and the clinical characteristics of resulting enteritis in children. Stool specimens from 1 665 children experiencing intestinal infection were collected by the Digestive Disorders Ward of Zhongshan Boai Hospital from March 2009 to October 2010. The drug sensitivity testing on 72 non-typhoidal Salmonella isolates was conducted after strain identification and separation. The clinical characteristics of non-typhoidal Salmonella infection were retrospectively analyzed. The results demonstrated that sensitivities of non-typhoidal Salmonella to cefoperazone-tazobactam, Tienam, levofloxacin, piperacillin-tazobactam, and ceftazidine were 100%, 98.61%, 95.83%, 87.50% and 77.78%, respectively. Antibiotic resistance rate of these non-typhoidal Salmonella to the first and second generation cephalosporins, aminoglycosides, non-enzyme penicillin and cephamycins were all>80%. Children with intestinal infection by non-typhoidal Salmonella typically presented with clinical characteristics specific to invasive enteritis such as mucous bloody stool, omitting and fever. Older children reported more abdominal pain and showed more abdominal distension and some may deteriorate to non-typhoidal Salmonella sepsis. This study suggests that non-typhoidal Salmonella may have a high sensitivity to carbapenems, enzyme-containing β-lactam compounds, and fluoroquinolones. Therefore, antibiotics should be chosen reasonably and prudently based on drug sensitivity testing as treatment for effectively controlling infection, and preventing the occurrence of further deterioration in patients.%为探讨非伤寒沙门菌的耐药性及其引起儿童肠炎的临床特点,收集2009年3月~2010年10月广东省中山市博爱医院儿科消化病区送检的1 665例肠道感染患儿粪便标本,将培养、分离所获的72株非伤寒沙门菌进行药敏试验,并回顾分析其感染后的临床特点.结

  14. 医院感染常见革兰阴性菌的临床分布及耐药性分析%Analysis Clinical Distrbution and Drug Resistance of Gram-negative Bacteria in Nosoconmial Infections

    Institute of Scientific and Technical Information of China (English)

    胡文祥; 彭吉军; 蒋华; 周旭

    2014-01-01

    目的:以了解医院感染革兰阴性菌的临床分布及耐药特点,为临床抗菌药物的应用提供依据。方法对2010年~2012年我院常见的医院感染革兰阴性菌的临床分布及耐药性进行回顾性分析。结果在医院感染细菌前5位的革兰阴性菌为大肠埃氏菌、肺炎克雷伯氏菌、铜绿假单胞菌、鲍氏不动杆菌、奇异变形杆菌、其次是产气肠杆菌、阴沟肠杆菌、食麦芽假单胞菌。细菌均呈现多耐药趋势,临床常用的第一、二、三代头孢菌素类、单环内酰胺类、头霉素类、部分β-内酰胺酶抑制剂由于细菌产ESBLs及AmpC而发生耐药,第四代头孢吡肟耐药率也达50%~60%,耐碳青霉烯类鲍氏不动杆菌由于碳青霉烯类抗菌药物的使用强度增加而显著增加,我院美罗培南、亚胺培南耐药率逐年明显上升已接近60%。而氨基糖苷类中的阿米卡星除鲍曼氏不动杆菌外由于近期少用使敏感性有所提高。结论分析医院感染常见感染细菌分布及耐药性,对指导临床合理应用抗菌药物及预防和控制耐药菌在医院内传播有着重要意义。%Objective To investigate the clinical distribution and drug resistance of gram-negative bacteria in nosoconmial infections and to proved the reference for reasonable use of the antibiotics.Methods The clinical distribution and drug resistance of gram-negative bacteria in nosoconmial infections from 2010 to 2012 were analysis by the means of retrospective survey.Results The top ifve were Escherichia coli, Klebsiella spp, Pseudomonas aeruginosa, Acinetobacter baumanii and Proteus mirabilis. The behind three were Enterobacter aerogenes, Enterbacter cloacae, Stenotrophomonas maltophilia. The gram-negative bacteria in nosoconmial infections were multidrug resistance to antibiotics. The 1, 2, 3 generation of cephalosporin, single ring lactam, Cephamycins antibiotics and part β-lactamase inhibitor were resistance to

  15. 牛源耐甲氧西林金黄色葡萄球菌的检测%Detection of Methicillin-resistant Staphylococcus aureus Strains Isolated from Bovine Mastitis

    Institute of Scientific and Technical Information of China (English)

    苏洋; 蒲万霞; 邓海平; 李春慧; 梁红雁; 陈智华

    2013-01-01

    本研究旨在了解甘肃地区奶牛乳房炎金黄色葡萄球菌的耐药性和耐甲氧西林金黄色葡萄球菌的感染情况,为奶牛乳房炎的防制提供理论依据.采用KB纸片扩散法,检测17株金黄色葡萄球菌对8种不同抗菌药物的敏感性;再用琼脂稀释法检测了苯唑西林、万古霉素对金黄色葡萄球菌的最小抑菌浓度(MICs);头孢西丁纸片扩散法和PCR扩增特异性mecA耐药基因对所有受试菌株进行全面的耐甲氧西林金黄色葡萄球菌检测.结果表明,菌株对青霉素、磺胺异恶唑具有较强抗性,而对环丙沙星、头孢唑啉、万古霉素和苯唑西林全敏感;头孢西丁纸片扩散法未能检测出表型为MRSA的阳性菌株,而PCR方法却检测出8株mecA基因阳性菌株,且这些菌株的苯唑西林MIC均小于2μg/mL.菌株的耐药情况较严重,对甲氧西林敏感而携带mecA基因的菌株高频存在于被调查地区的奶牛场中.%The aim of present study was to investigate the antimicrobial resistance, and the prevalence of methicillin-resistant Staphylococcus aureus (S. aureus) isolated from bovine mastitis in Gansu province, to provide credible theory evidence for prevention and treatment on bovine mastitis. Eight commonly used antimicrobial agents were used for determining antimicrobial susceptibility of 17 total S. aureus strains by disk diffusion method. Agar screen method was used for determining the oxacil-lin and vancomycin minimum inhibitory concentration value as well. Disk diffusion method using the cephamycin antibiotics ce-foxitin and detection of mecA gene by PCR assay were performed to detect the presence of MRSA. Most of strains showed a high resistance for penicillin and sulfafurazole, yet keeping complete sensitivity for ciprofloxacin, cefazolin, vancomycin and ox-acillin. None MRS A isolate was identified by the phenotypic detection method, but eight MRSA isolates with the MIC of oxac-illin lower than 2 μg/mL were

  16. 某院腹腔镜阑尾切除术患者围术期抗菌药物应用分析%Perioperative Use of Antibiotics in Patients Undergoing Laparoscopic Appendectomy in a Hospital

    Institute of Scientific and Technical Information of China (English)

    李小燕; 许利敏

    2014-01-01

    OBJECTIVE:To investigate the perioperative use of prophylactic antibiotics in patients undergoing laparoscopic ap-pendectomy in a hospital before and after carrying out the special rectification activity on antibiotic use. METHODS:The utiliza-tion data of antibiotics in surgical patients undergoing laparoscopic appendectomy in a hospital before and after carrying out the rec-tification activity on antibiotic use (in 2012 vs. in 2013) were analyzed statistically. RESULTS:Perioperative use of prophylactic antibiotics was noted in 100% of the patients before and after the rectification activity. Before carrying out the rectification activity, the top 5 drugs in terms of usage frenquency were ornidazole,cefoxitin,cefotiam,cefmetazole and cefoperazone/tazobactam,with drugs used for 6.3 days on average;after carrying out the rectification activity,only 3 kinds were used,the use of cephamycins and special antibiotics were discontinued and the antibiotics were used for an average of 4.2 days. CONCLUSIONS:The periopera-tive use of prophylactic antibiotics in patients undergoing laparoscopic appendectomy is improved after carrying out special rectifica-tion activity on antibiotics.%目的:对比抗菌药物专项整治活动前后某院普外科腹腔镜阑尾切除术患者围术期预防性应用抗菌药物情况。方法:查阅该院普外科2012年(整治前)及2013年(整治后)腹腔镜阑尾切除术患者的出院病历,对各病历中抗菌药物的应用数据进行统计、分析。结果:该院整治前后患者围术期预防性抗菌药物使用率均为100%。整治前应用例次列前5位的药品分别是奥硝唑、头孢西丁、头孢替安、头孢美唑、头孢哌酮/他唑巴坦钠,平均用药时间为6.3 d;整治后共使用3个品种,头霉素及特殊级抗菌药物未再使用,抗菌药物平均用药时间为4.2 d。结论:抗菌药物整治活动后,该院普外科腹腔镜阑尾切除术患者围术期抗菌药

  17. Regeneration System and Influencing Factors of Maize in Ningxia%宁夏玉米高效再生体系的建立及其影响因素

    Institute of Scientific and Technical Information of China (English)

    甘晓燕; 王劲东; 陈虞超; 李欣; 佘奎军; 李苗; 石磊; 宋玉霞

    2011-01-01

    以4个宁夏玉米品种幼胚为材料,采用组织培养法,研究培养基类型、基因型、外源激素、头孢霉素(Cef)对玉米幼胚培养及再生的影响.结果表明,在愈伤组织诱导过程中,Ⅰ号和Ⅱ号培养基诱导率较高,宁玉12号和宁0816的胚性愈伤组织诱导率相对较高,达到85.3%和82.1%;6-BA对不同基因型愈伤组织分化率的影响不同,添加6-BA对愈伤组织的分化均有促进作用;此外,当Cef质量浓度高于500 mg/L时,愈伤组织分化明显受到抑制.最佳诱导培养基为基本元素N6+水解酪蛋白200 mg/L+脯氨酸690 mg/L+2,4-D 2.0 mg/L+蔗糖30 g/L+肌醇100 mg/L+AgNO3 10 mg/L,最佳分化培养基为基本培养基N6+ 6-BA1.0 mg/L+蔗糖50 g/L.%Using immature embryo of four maize varieties in Ningxia as explants and utilizing the plant tissue culture method,the effect of medium type,genotype,exogenous hormone and cephamycin (Cef) on in vitro culture and regeneration was studied. The results showed that different medium type and genotype showed different ability of embryogenic callus inducing. I and Q had more high rate of induction, Ningyu 12 and Ning 0816 had high rate as 85. 3% and 82. 1% respectively;6-BA were the most important factor for the induction of differentiation of embryogenic callus, 6-BA could promote the differentiation of embryogenic callus. Respectively,when 500 mg/L of Cef was added,the differentiation of callus was significant inhibited. The best inducing medium was N6 + Casein hydrolysate 200 mg/L+Pro 690 mg/L+2,4-D 2. 0 mg/L + Sugar 30 g/L+Inositol 100 mg/L+AgNO310 mg/L, The best differentiation medium was: N6 + 6-BA1.O mg/L+Sugar 50 g/L.

  18. 肾盂肾炎患者经验用抗菌药物与药敏结果符合率%Coincidence rates between empiric antimicrobial use and antimicrobial sus-ceptibility testing results in patients with pyelonephritis

    Institute of Scientific and Technical Information of China (English)

    张海谱; 梁霞; 贾克然; 赵会海; 史文俊; 王缚鲲

    2016-01-01

    antimicrobial agents were involved,the most frequently used antimicrobial agents were third generation ceph-alosporins,cephamycins,and fluoroquinolones.The overall,partial,and non-coincidence rate between antimicrobial use and antimicrobial susceptibility testing results were 64.32%(n=402),8.32%(n=52),and 27.36%(n=171)respective-ly.The overall coincidence rate in patients with acute pyelonephritis was higher than those with chronic pyelonephritis (77.61% [n=357]vs 58.79%[n=97],P <0.05).The overall coincidence rate in patients <50 years old and ≥50 years old were 68.12%(156/229)and 75.25%(298/396)respectively,there was no significant different between two groups (χ2 =2.93,P =0.09).Conclusion The non-coincidence rate between empiric antimicrobial use and antimicrobial suscepti-bility testing results is high,measures needs to be taken to improve the empiric antimicrobials use.

  19. Elimination of indigenous endophytic bacteria in Eucalyptus urophylla by heat and antibiotics treatment%热处理和抗生素对桉树固有内生细菌去除的研究

    Institute of Scientific and Technical Information of China (English)

    宋艳祥; 王玉凤; 冉隆贤

    2011-01-01

    In order to obtain endophytic bacteria free seedlings of Eucalyptus urophylla , three methods were applied to eliminate or inhibit the indigenous endophytic bacteria in E. Urophylla, I. E. , heat treatment of the seeds of E. Urophylla at stable and variated high temperatures, heat treatment of seedlings from tissue culture of E. Urophylla combined with apical meristem culture, and antibiotics treatment of the seedlings grown in tissue culture. A differential staining procedure was used to detect the existence of endophytic bacteria and hemacytometer counting method was used to study the bacterial population. The results showed that there was no obvious effect in the elimination of endophytic bacteria by heat treatment of the seeds, and the bacteria in root of treated seedlings had a bit more population than that of control. However, the bacteria in stem and leaf of treated seedlings had less population than those of control. After the heat treatment of seedlings combined with shoot-tip culture, the endophytic bacteria can be removed effectively as the temperature increased daily, with less number compared with control. And when it reached 40 ℃ , the bacterial growth was inhibited largely. Heat treatment at 37 ℃ reduced the number of indigenous bacteria at 20th and 21st day, with a population of 5. 33 × 108 CFU/g and 4. 02 × 108 CFU/g, respectively, and only about one seventh of the number of control at 3. 43 × 109 CFU/g. When the temperature for heat treatment reached 40 ℃ , the number of bacteria decreased to 1. 63×108 CFU/g, occupied only one forty-seventh of the bacteria number of control at 7. 70 × 109CFU/g, indicating that treatment with higher temperature at 37 ℃ and 40℃ could significantly reduce the number of bacteria in seedlings grown in vitro culture. The population of the endophytic bacteria of E. Urophylla increased obviously after growing in the MS supplemented with antibiotics, I. E. , oxytetracycline, tetra-cycline and cephamycins

  20. 卫生部全国细菌耐药监测网2011年女性尿标本来源细菌耐药监测%Ministry of Health National Antimicrobial Resistance Investigation Net annual report of 2011 : bacterial resistances monitor of women urine samples

    Institute of Scientific and Technical Information of China (English)

    齐慧敏; 吕媛

    2012-01-01

    Objective To summarize bacterial resistance in the women clinical urine culture samples collected in 2011 from 149 hospitals of Mohnarin. Methods Conventional culture, automatic clinical microbiological system, disk diffusion and E — test methods were used for antibacterial activity of antimicrobial agents and resistances and sensitivity were calculated by using WHONET5. 6 software. Results A total of 32682 strains of bacteria were isolated, of which of E. Coli, Enterococcus faeci-um, Enterococcus faecalis, Klebsiella pneumonia and Proteus mirabilis, respectively. The antimicrobial agents with lower antibiotic resistance rates of E. Coli were carbapenems ( 0.6%), piperacillin/tazobactam (3. 7% ) , nitrofurantoin ( 5. 3% ) , cefoperazone / sulbactam ( 5. 5% ) , amikacin (6. 0% ) ,fosfomycin (8. 7% ) .cefoxitin ( 12. 0% ) ,ticarcillin/ clavulanic acid (12. 5% ) , and amoxicillin/clavulanic acid ( 15. 5% ) , respectively. That of Enterococcus spp. Were teicoplanin(0. 4% -2. 4% ), vancomycin ( 1. 2% — 4. 6% ) , amoxicillin / clavulanic acid (1.4% — 11.3%), piperacillin/tazobactam (8. 1 - 15. 5% ) ,fosfomycin (5. 3% -20. 2% ) and nitrofurantoin (5. 9% - 49. 0% ) , respectively. No linezol id resistant Enterococcus were found. Conclusion E. Coli remains the urinary tract infection major pathogen but the proportion of Enterococci was significantly increased. The overall results of antibiotic resistance were serious. Nitrofurantoin, fosfomycin and amoxicillin / clavulanic acid can be chose as empirical treatment of oral antibiotics. Antimicrobial agents with enzyme inhibitor, cephamycin aminoglycosides and carbapenems can be chose as empirical treatment of injection antibiotics.%目的 总结我国2011年临床女性尿标本来源细菌耐药状况.方法 149家医院女性尿标本中的细菌,用自动化临床微生物测定方法、纸片法或E-test法测定细菌药物敏感性,用WHONET 5.6软件进行分析.结果 共分离细菌32682株,其中排在前5位