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Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ticarcillin is resistant to the action of cephalosporinases, which explains its biological activity on a large number of bacterial species, including cephalosporinase-producing Enterobacteriaceae and Pseudomonas aeruginosa. Nevertheless, its antibacterial activity is often limited by the action of some beta-lactamases, mostly plasmid-mediated penicillinases. Clavulanic acid by itself has poor antibacterial activity, but its most important property is to inhibit and inactivate beta-lactamases. The inhibitory properties of clavulanic acid were studied on a large number of beta-lactamases. The penicillinases produced by Staphylococcus aureus, the plasmid-mediated beta-lactamases such as the TEM-type, the chromosomally-mediated penicillinases from Klebsiella pneumoniae and other closely-related beta-lactamases, and a few chromosomally-mediated cephalosporinases, such as that produced by Proteus vulgaris, are powerfully inhibited by clavulanic acid. The plasmid-mediated penicillinases of OXA type and most of the chromosomally-mediated cephalosporinases, such as that produced by Escherichia coli (Amp C), are less or poorly inhibited. Moreover, clavulanic acid has some cephalosporinase-inducing properties. These properties are in good agreement with the bacteriological properties of Timentin.
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PMID:Timentin and beta-lactamases. 348 38

Foramidocillin is a 6-alpha-formamido penicillin with a 6-beta-acylureido side chain. The majority of the Enterobacteriaceae were inhibited by less than or equal to 1 microgram of foramidocillin per ml, and Pseudomonas aeruginosa was inhibited by 4 micrograms/ml. Foramidocillin had activity comparable to those of ceftazidime, imipenem, and aztreonam against beta-lactamase-producing members of the Enterobacteriaceae and P. aeruginosa, and it inhibited organisms resistant to piperacillin. Foramidocillin did not inhibit gram-positive species or anaerobic gram-negative bacteria. Foramidocillin was not hydrolyzed by the common plasmid-mediated beta-lactamases TEM-1, TEM-2, OXA-2, PSE-4, and SHV-1, by the chromosomal beta-lactamases P99 of Enterobacter cloacae and K1 of Klebsiella oxytoca, or by the Sabath-Abraham enzyme of P. aeruginosa.
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PMID:Antimicrobial activity and beta-lactamase stability of foramidocillin. 348 17

A study has been conducted to identify the beta-lactamases most likely to contribute to beta-lactam resistance in clinical populations and to investigate their interactions with cefuroxime and newer cephalosporins. A total of 217 ampicillin-resistant, Gram-negative isolates from faecal samples of healthy volunteers in Germany, South America and Amman were investigated. Such strains represent the 'gene pool' from which infections might arise. Escherichia coli was the prevalent species (59.9%) followed by Klebsiella spp. (20.3%) and Enterobacter cloacae (12.0%). At least 56.7% and possibly as high as 64.5% of strains owed their principal beta-lactamase activity to enzymes mediated by R-plasmids. The most prevalent R-plasmid mediated beta-lactamase was TEM-1 which was produced by 109 strains. The beta-lactamase activity of strains producing only a chromosomal enzyme was often markedly higher than that of strains also producing an R-plasmid mediated enzyme. The qualitative and quantitative aspects of beta-lactamase production were investigated in cell free and whole cell tests and this confirmed the superior broad spectrum beta-lactamase resistance of ceftazidime over other new cephalosporins.
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PMID:Qualitative and quantitative aspects of beta-lactamase production as mechanisms of beta-lactam resistance in a survey of clinical isolates from faecal samples. 348 8

The beta-lactamase stability and interactions of imipenem were analysed in comparison with those of cefazolin, cefuroxime, cefoxitin, cefotaxime, ceftazidime, mezlocillin, piperacillin and penicillin G for a set of representative beta-lactamases. These enzymes included penicillinases such as those obtained from Staphylococcus aureus, Escherichia coli and other Enterobacteriaceae (TEM-1 and similar enzymes) (group A); cephalosporinases produced by Esch. coli (Amp C type), Serratia liquefaciens, Enterobacter cloacae, Pseudomonas aeruginosa (group B); and beta-lactamases produced by Klebsiella spp., Proteus vulgaris and Bacteroides fragilis and with a high hydrolytic activity for the newer cephalosporins (group C). Enzymes of group A were demonstrated to be highly active against penicillins and also against the early cephalosporins; enzymes of group B showed hydrolytic activity for all other tested compounds, including the newer cephalosporins and cephamycins, but not imipenem, whereas enzymes of group C were highly active against the new cephalosporins but not against cephamycins and imipenem. In conclusion, imipenem shows a moderate affinity for all these enzymes but no detectable hydrolysis.
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PMID:Beta-lactamase stability of imipenem. 349 36

The in vitro activity of CGP 31608, a new penem, against aerobic and anaerobic organisms was evaluated and compared with those of other beta-lactams. CGP 31608 inhibited Escherichia coli, Klebsiella pneumoniae, K. oxytoca, Proteus mirabilis, Citrobacter diversus, and Salmonella, Shigella, Aeromonas, and Yersinia spp. with MICs for 50% of the strains (MIC50s) of 2 to 4 micrograms/ml and MIC90s of 4 micrograms/ml, compared with cefotaxime, ceftazidime, aztreonam, and imipenem MICs of less than 0.25 microgram/ml. MIC90s were 8 micrograms/ml for Enterobacter species and C. freundii, for which other agents had MICs of 32 micrograms/ml, except imipenem, which had equal activity. The MIC90 for Proteus vulgaris, Morganella morganii, Providencia stuartii, and Providencia rettgeri was 8 micrograms/ml, compared with less than 2 micrograms/ml shown by the other agents. Acinetobacter species resistant to other agents except imipenem were inhibited by 4 micrograms/ml, as were Pseudomonas aeruginosa, including piperacillin-, ceftazidime-, and gentamicin-resistant isolates. The MIC for P. cepacia, P. fluorescens, and P. acidovorans was less than or equal to 8 micrograms/ml, but that for P. maltophilia was greater than or equal to 128 micrograms/ml. Hemolytic streptococci A, B, C, G, and F were inhibited by less than 1 micrograms/ml, but the MIC for Streptococcus faecalis was greater than or equal to 32 micrograms/ml. MICs for Staphylococcus aureus methicillin-susceptible and -resistant strains were less than or equal to 1 microgram/ml, as were those for methicillin-susceptible and -resistant S. epidermidis. Bacteroides fragilis and Clostridium species and Fusobacterium spp. were inhibited by less than or equal to 4 micrograms/ml. CGP 31608 was not hydrolyzed by plasmid beta-lactamases TEM-1, TEM-2, SHV-1, PSE-1, OXA-2, PSE-4, or by S. aureus. Chromosomal beta-lactamases of type Ia in Enterobacter cloacae P99 and Morganella morganii, Ic in P. vulgaris, K-1 in K. oxytoca, and Id in P. aeruginosa also did not hydrolyze CGP 31608. It inhibited TEM-1, but the 50% inhibitory concentration was 14.2 micrograms/ml compared with 0.15 micrograms/ml for the P99 enzyme. CGP 31608 induced beta-lactamases in P. aeruginosa, E. cloacae, C. freundii and Providencia rettgeri, but there was no increase in MICs for the isolates and it did not select strains derepressed for beta-lactamase production. Synergy of CGP 31608 and gentamicin was found against 90% P. aeruginosa, 60% Enterobacter cloacae, and 50% Serratia marcescens strains. No synergy was found with rifampin. A postantibiotic effect was found against E. coli.
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PMID:In vitro activity and beta-lactamase stability of a new penem, CGP 31608. 349 45

Although still there are Klebsiella strains which do not harbour plasmids and produce constitutive chromosomal beta-lactamases, recently clinical isolates were found in ever increasing numbers carrying mainly TEM-, CARB- and OXA type R-factors. We selected four chromosomal cephalosporinase producing Klebsiella strains to study the pI values of the enzymes and their simultaneous separability from accompanying proteins by chromatofocusing techniques. We compared pI values of the pure and the crude preparations: K. pneumoniae K1 SC 10436: pIpure = 6.4, pIcrude = 6.42; K. aerogenes K1 1082 E: pIpure = 6.5, pIcrude = 6.5; K. oxytoca 1082 E: pIpure = 6.42, pIcrude = 6.4; K. oxytoca 20: pIpure = 7.62, pIcrude = 7.6. Excellent agreement of the pI values among each other, but occasional differences with those obtained by analytical isoelectrofocusing are attributed to methodological diversities and to the presence of satellite enzymes, known to exist in Klebsiella.
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PMID:Use of chromatofocusing for separation of beta-lactamases. VIII. Analytical chromatofocusing of chromosomal cephalosporinases from four Klebsiella strains. 350 Jan 79

Sixty-three percent homology of nucleotide sequence and 67% homology of deduced amino acid sequence were found between the chromosomally encoded beta-lactamase gene of Klebsiella pneumoniae and the TEM beta-lactamase of transposon Tn3. Moreover, 22 out of 24 amino acid residues are identical around the predicted active site. It is therefore suggested that these two kinds of beta-lactamases share a common evolutionary origin. The 0.5 kb DNA fragment of the cloned gene hybridized specifically with the chromosomal DNA of all the K. pneumoniae strains tested which had been isolated in Japan, USA and Europe.
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PMID:Close evolutionary relationship between the chromosomally encoded beta-lactamase gene of Klebsiella pneumoniae and the TEM beta-lactamase gene mediated by R plasmids. 353 26

A prevalence study was carried out on a 100-bed Veterans Administration nursing home care unit to determine the extent of colonization with gentamicin-resistant gram-negative bacilli (GRGNB). Hand cultures of 12 employees and 17 environmental cultures were negative. Twenty-six of 86 (30%) patients were colonized with 49 GRGNB. Sixteen patients (19%) had urinary colonization. Multivariate analysis revealed significant associations between rectal or perineal colonization (P less than 0.01), and the presence of a urinary device (82% condom catheters) (P less than 0.05), with urinary colonization. The most common isolates were Providencia stuartii (20), Escherichia coli (nine) and Klebsiella pneumoniae (nine). Twenty-six of 49 isolates carried plasmids. Restriction endonuclease digestion of plasmid DNA was performed for 21. Cross-colonization, as defined by the presence of the identical species with the identical restriction endonuclease digestion profile of purified plasmid DNA found in different patients, was observed for eight of 21 (38%) strains. All were geographically clustered. No strains could transfer gentamicin-resistance by conjugation and only two plasmids could transform our E coli recipient to gentamicin resistance. One E coli plasmid was identical to two Citrobacter freundii plasmids and a P stuartii plasmid isolated from three different patients. This 105 kb plasmid is conjugative and encodes resistance to ampicillin, carbenicillin, tetracycline, and sulfonamides. Thus, 57% of strains were cross-colonizing or contained identical R-plasmids. Southern hybridization using a 1 kb TEM-1 gene probe demonstrated sequences homologous to this probe in five of five nursing home plasmids examined.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prevalence of colonization with antibiotic resistant gram-negative bacilli in a nursing home care unit: the importance of cross-colonization as documented by plasmid analysis. 353 83

p-Nitrobenzyl 2 beta-[(benzoyloxy)methyl]-2 alpha-methylpenam-3 alpha-carboxylate was prepared by reaction of p-nitrobenzyl 2-[2-oxo-3 alpha-bromo-4-(benzothiazol-2-yldithio)azetidin-1-yl] -2-isopropenylacetate with silver benzoate in the presence of iodine. The resulting diester was oxidized to the sulfone with potassium permanganate and hydrogen peroxide, and the bromine and p-nitrobenzyl groups were removed by hydrogenolysis to give potassium 2 beta-(benzoyloxy)methyl 2 alpha-methylpenam-3 alpha-carboxylate 1,1-dioxide. A series of related compounds, including the pivaloyl, methoxybenzoyl, p-fluorobenzoyl, and p-aminobenzoyl derivatives, were prepared in a similar way. All of these compounds were potent beta-lactamase inhibitors in vitro against the TEM beta-lactamase from Klebsiella pneumoniae A22695 and Bacteroides fragiles A22695 but less active against the beta-lactamase from Staphylococcus aureus A9606. All compounds when administered orally in a 1:1 combination with amoxicillin did not show any significant protection of mice infected with S. aureus A9606. 2 beta-(Bromomethyl)-2 alpha-methylpenam-3 alpha-carboxylic acid was prepared and reacted with silver nitrate to give the nitrate ester. Oxidation with potassium permanganate and catalytic reduction afforded 2 beta-(hydroxymethyl)-2 alpha-methylpenam-3 alpha-carboxylic acid 1,1-dioxide. 2 beta-(Bromomethyl)-2 alpha-methylpenam-3 alpha-carboxylic acid 1,1-dioxide was found to be a strong beta-lactamase inhibitor, while the 2 beta-hydroxymethyl compound showed only weak beta-lactamase-inhibiting properties.
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PMID:Synthesis and beta-lactamase inhibitory properties of 2 beta-[(acyloxy)methyl]-2-methylpenam-3 alpha-carboxylic acid 1,1-dioxides. 387 69

We studied the plasmid and antibiotic resistance characteristics of 35 strains of Enterobacteriaceae recovered from faecal specimens of children with diarrhoea in Central General Hospital, Bandung, Indonesia. Twenty three Escherichia coli, three Providencia, three Proteus, three Klebsiella, two Enterobacter and one Citrobacter were examined. All strains were multiply resistant, many carrying six to nine antibiotic resistances. Most of these resistances were transferable to a laboratory E. coli strain and were carried on large-sized plasmids. All recently-described tetracycline resistance determinants (Classes A----D) were represented; the most common was the Class B, or TN10 type. The TEM-1 beta-lactamase was detected in 17 out of 21 ampicillin-resistant strains examined. The OXA-1, PSE-1, and SHV-1 enzymes were also found. Of 23 plasmids tested, all could be classified into one of eight different incompatibility groups: IncFII, IncN, IncB, IncF1, IncI1, IncI2, IncH2 and IncT. These studies demonstrate the existence of large multiresistant transferable plasmids representing common incompatibility groups and bearing common tetracycline and ampicillin resistance determinants in enteric strains isolated from children hospitalized in Indonesia.
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PMID:Multiple antibiotic resistance plasmids in Enterobacteriaceae isolated from diarrhoeal specimens of hospitalized children in Indonesia. 387 28


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