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Query: UMLS:C0276640 (TEM)
 20,729 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reference strains of Escherichia coli (ampicillin-susceptible and -resistant ATCC strains, and known TEM-1 and TEM-2 beta-lactamase producers) were tested in vitro and in the in-vivo mouse thigh infection model against four beta-lactamase inhibitor compounds (BICs: amoxycillin/clavulanic acid, ampicillin/sulbactam, ticarcillin/clavulanic acid, and piperacillin/tazobactam), selected cephalosporins, and imipenem. The ATCC strains (ampicillin-susceptible and -resistant) were susceptible to the BICs in disc and MIC tests. Three or more logs of killing were observed at the NCCLS breakpoint concentrations. However, the TEM-1 and TEM-2 producers were resistant in disc tests to ampicillin/sulbactam and amoxycillin/clavulanic acid, and showed intermediate susceptibility to ticarcillin/clavulanic acid. MICs were at or near the breakpoint, but bactericidal activity was only noted at the probable breakpoint concentration of piperacillin/tazobactam. Cefoxitin, cefotaxime, cefpirome and imipenem, but not cephalothin, showed greater bactericidal activity and lower MICs for the TEM-producing strains than the BICs. The viable count of the TEM-1 producer was not reduced in the mouse thigh model by ampicillin/sulbactam or amoxycillin/clavulanic acid, but cefpirome and cefotaxime reduced the viable count by approximately three logs. There was a 50% mortality rate in mice receiving the two BICs. The ampicillin-susceptible ATCC strain of E. coli was killed to a similar degree by all agents tested. Overall, the BICs appeared inferior, in both in-vivo and in-vitro tests to selected cephalosporins and imipenem when tested against reference strains of E. coli producing TEM-1 or TEM-2 beta-lactamase. The large inoculum effect and poor bactericidal activity observed with the BICs suggest they could be less effective in certain clinical situations.
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PMID:An in-vitro and in-vivo comparison of the activity of beta-lactamase inhibitor combinations with imipenem and cephalosporins against Escherichia coli producing TEM-1 or TEM-2 beta-lactamase. 142 30

The NCTC type strains and four clinical isolates of Enterobacter cloacae, Citrobacter freundii, Serratia marcescens, Morganella morganii, Providencia stuartii and Pseudomonas aeruginosa were exposed, in agar, to cefepime at 3, 5, and 10 x MIC and a breakpoint concentration of 16 mg/L. Mutants were selected at a frequency of approximately 10(-8) that had decreased susceptibility to cefepime and cefpirome, and species-dependent resistance to other beta-lactams. Any putative mutant with a greater than four-fold increase in the MIC was examined to determine its beta-lactamase expression and outer membrane protein (Omp) profile. Mutant strains of P. stuartii and M. morganii lacked an Omp of molecular mass similar to that of OmpF, and were cross-resistant to nalidixic acid. Mutant strains of E. cloacae had derepressed class I beta-lactamase production and lacked an Omp corresponding to OmpF, suggesting that in this species both parameters are necessary for decreased susceptibility. Derepressed beta-lactamases purified from mutant strains of E. cloacae, C. freundii and P. stuartii was able to hydrolyse cefepime, but not as quickly as TEM-10.
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PMID:Selection and characterization of cefepime-resistant gram-negative bacteria. 177 70

The in vitro activity of ME-1206, a new aminothiazolyl cephalosporin that can be orally absorbed when converted to an ester, was compared with that of other beta-lactams. ME-1206 inhibited 50% of the Enterobacteriaceae at 2 micrograms/ml, similar to cefotaxime, ceftazidime, and cefixime. It did not inhibit, MIC greater than or equal to 32 micrograms/ml, Enterobacter species or Citrobacter freundii resistant to cefotaxime and ceftazidime, and it was less active than cefotaxime and ceftazidime against Serratia marcescens. Haemophilus influenzae, Neisseria gonorrhoeae, and Moraxella catarrhalis were inhibited by less than or equal to 0.25 micrograms/ml of ME-1206 inhibited hemolytic streptococci groups A, B, C, and G, MIC90 0.06 micrograms/ml, but it did not inhibit enterococci. Pseudomonas aeruginosa and other pseudomonads were resistant to ME-1206. MICs and MBCs of ME-1206 for susceptible species were within a dilution. ME-1206 was not hydrolyzed by TEM-1 or TEM-2, but was hydrolyzed by TEM-3 and TEM-5. ME-1206 was hydrolyzed by beta-lactamases of Morganella, Proteus vulgaris, and K1 of Klebsiella oxytoca, but minimally by the P99 beta-lactamase of Enterobacter cloacae. ME-1206 is comparable in in vitro activity and beta-lactamase stability to many of the current cephalosporins.
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PMID:In vitro activity of a new cephalosporin ME-1206 compared with other agents. 179 56

From 1983 to 1989, 520 Escherichia coli blood culture pathogens were isolated from two hospitals in Turku, Finland. Ampicillin resistance (MIC greater than or equal to 16 micrograms/ml) of these isolates increased from 33% in 1983 to 66% in 1987, but decreased to 38-49% in 1988-1989. Occurrence of TEM-1 beta-lactamase producing isolates increased only slightly from 14% in 1983 to 25% in 1989 among all Escherichia coli strains studied. Strains with ampicillin MIC values of 16 micrograms/ml and 32 micrograms/ml were mostly responsible for the increase in resistance. Among these isolates, TEM-1 or any other of the well known plasmid-mediated beta-lactamases were not found by hybridization or isoelectric focusing.
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PMID:Analysis of beta-lactamase production in ampicillin-resistant Escherichia coli isolated from blood cultures 1983-1989. 180 99

In October 1988, all non repetitive strains of K. pneumoniae isolated in 17 hospitals have been studied. Among these 590 strains: 451 (76%) only produce the specific beta-lactamase of the species SHV-1 (pI 7,7) or SHV-1 type (pI 7,1), while 74 (12.5%) produce a TEM-1 or TEM-2 type beta-lactamase, and 65 (11%) an extended broad spectrum beta-lactamase: 22 CTX-1, 5 SHV-2, 4 SHV-3, 26 SHV-4, 8 SHV-5. The minimum inhibitory concentrations of the following antibiotics were performed by a liquid micro dilution technic: amoxicillin (AMX), amoxicillin + clavulanic acid (CL), 5 mg/l, ticarcillin (TIC), piperacillin (PIP), cefazolin (CEZ), cefamandole (CFM), cefoperazone (CFP), cefotaxime (CTX), cefotaxime + clavulanic acid 5 mg/l, cefotaxime + sulbactam (SUL) 5 mg/l, cefpirome (CPI), ceftazidime (CAZ), azthreonam (AZT), latamoxef (MOX), cefoxitin (FOX), cefotetan (CTT), temocillin (TMO), imipenem (IMI). The "wild" strains with SHV-1 beta-lactamase are resistant to AMX and have a decreased susceptibility to TIC and PIP, but are susceptible to other antibiotics. The TEM producing strains are more resistant to PIP and TIC, have a decreased susceptibility to CEZ and CFM but are susceptible to other antibiotics. For the extended broad-spectrum beta-lactamase producing strains, the MIC of penicillin antibiotics (AMX, TIC, PIP) are very high and also the MIC of CEZ, CFM and CFP. The MIC of CTX are higher for CTX-1 or SHV-4 producing strains, than for SHV-2, SHV-3, or SHV-5 producing strains. The combination with CL is more efficacious than the one with SUL to reduce the MIC of CTX in susceptibility area.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Comparative activities of 15 beta-lactam antibiotics against 590 strains of Klebsiella pneumoniae according to the production of beta-lactamase]. 188 69

The in vitro activity of GR69153, a new catechol-substituted cephalosporin, was compared with those of ceftazidime, imipenem, meropenem, and ceftriaxone against 604 recent clinical isolates and other strains with known mechanisms of resistance. The MICs of GR69153 for 90% of the members of the family Enterobacteriaceae tested were less than 0.5 micrograms/ml, with the exceptions of those for Serratia spp. (4 micrograms/ml), Citrobacter spp. (2 micrograms/ml), and Enterobacter spp. (8 micrograms/ml). Ninety percent of Pseudomonas aeruginosa isolates were susceptible to less than or equal to 1 microgram of GR69153 per ml. With the exception of methicillin-resistant strains, 90% of Staphylococcus aureus isolates were susceptible to less than or equal to 2 micrograms/ml, and GR69153 was four- to eightfold more active than ceftazidime and ceftriaxone against these strains. Isolates of Haemophilus influenzae, Branhamella catarrhalis, Neisseria spp., and Streptococcus pneumoniae (penicillin susceptible) were highly susceptible (MIC for 90% of the strains, less than or equal to 0.12 micrograms/ml). GR69153 was stable to hydrolysis by the TEM-1 and TEM-5, SHV-1 and SHV-2, and K1 beta-lactamases, but some susceptibility to hydrolysis by the TEM-3, TEM-9, and P99 enzymes was observed. The protein-binding activity of GR69153 was 74.5 to 66.8%, depending on the concentration, and serum had little effect upon activity.
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PMID:In vitro activity of a catechol-substituted cephalosporin, GR69153. 202 66

We studied the activity of the combination of sulbactam and ceftriaxone against a Klebsiella pneumoniae strain producing TEM-3, a new extended-broad-spectrum beta-lactamase, in an endocarditis model. In vitro, ceftriaxone was strongly inactivated in the presence of TEM-3 (MBC, 128 micrograms/ml with an inoculum of 5 x 10(5) CFU/ml). A marked inoculum effect was demonstrated with sulbactam: effective concentrations of inhibitor needed to reduce the MIC and MBC of ceftriaxone to similar levels increased from 1 microgram/ml in the presence of an inoculum of 5 x 10(5) CFU/ml to 20 micrograms/ml in the presence of an inoculum of 1 x 10(7) CFU/ml. In vivo, sulbactam given at 200 mg/kg of body weight every 12 h, a dosage higher than that previously reported to be effective against rabbit endocarditis caused by other microorganisms, was not sufficient to restore the complete activity of ceftriaxone given at 30 mg/kg once daily for 4 days. This insufficient activity may be correlated with the presence of a high level of beta-lactamase inside the vegetations, as indicated by a quantitative in vitro assay of beta-lactamase activity in the cardiac vegetation, suggesting an insufficient inactivation of the extended-broad-spectrum beta-lactamase in vivo.
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PMID:Ceftriaxone-sulbactam combination in rabbit endocarditis caused by a strain of Klebsiella pneumoniae producing extended-broad-spectrum TEM-3 beta-lactamase. 207 99

The effectiveness of a combination of the recently developed penam sulphone tazobactam with piperacillin was studied in clinical isolates with defined beta-lactamase production. The combination was highly effective against piperacillin-resistant beta-lactamase-producing Staphylococcus aureus, TEM-1-producing Escherichia coli and Proteus vulgaris isolates. It was less effective against E. coli isolates producing the OXA-1 enzyme and marginally active against TEM-1-producing Klebsiella spp. isolates. The presence of tazobactam at a concentration of 10 mg/l markedly reduced the minimal inhibitory concentrations for piperacillin in most of the beta-lactamase-derepressed Enterobacter cloacae, Serratia marcescens and Citrobacter freundii isolates; however, this synergism was much less pronounced in beta-lactamase-derepressed Klebsiella spp. isolates. The selection frequency of resistant clones from clinical E. cloacae and C. freundii isolates could be markedly reduced by the addition of 10 mg/l tazobactam to the piperacillin-containing selective medium. Resistant clones could be obtained only from part of the wild-type strains at 2 or 4 times the MIC of piperacillin in the presence of tazobactam, whereas resistant clones could be selected up to 64 times the MIC of piperacillin without the addition of tazobactam. This aspect deserves attention with respect to the rapid selection of beta-lactamase-derepressed clones from nosocomial pathogens.
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PMID:Antibacterial activity of piperacillin and tazobactam against beta-lactamase-producing clinical isolates. 217 81

Reexamination of Serratia marcescens isolates obtained in 1982 revealed two organisms that were resistant to the penem FCE 22101 (MIC, 512 micrograms/ml) and imipenem (MIC, 16 micrograms/ml) and that had slightly reduced susceptibilities to meropenem (MIC, 0.12 micrograms/ml). MICs of these agents for typical S. marcescens isolates were 1 to 8, 0.25 to 0.5, and 0.03 micrograms/ml, respectively. The two isolates were fully susceptible to broad-spectrum cephalosporins, and only one was highly resistant to ampicillin and carbenicillin (MICs, greater than 1,024 micrograms/ml). Both isolates had beta-lactamases that focused at pIs 8.2 and 9.7. The penicillin-resistant isolate additionally produced the TEM-1 enzyme. The enzymes with pIs of 8.2 and 9.7 were separated by cation-exchange chromatography. The pI 8.2 beta-lactamase was a class I enzyme of the type found in most S. marcescens isolates. It was almost inactive against carbapenems and penems, as was the class I enzyme from another S. marcescens strain. The pI 9.7 enzyme hydrolyzed penems and carbapenems rapidly: kcat (turnover number) values for FCE 22101, imipenem, and meropenem were 3.4, 26, and 1% of the kcat value for cephaloridine, respectively; kcat/Km values were 140, 915, and 150% of the kcat/Km value for cephaloridine, respectively. Otherwise, the pI 9.7 enzyme had predominantly penicillinase activity. It was inhibited more readily by clavulanate than by tazobactam and was inactivated by the chelating agents EDTA and ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid. Expression of the pI 9.7 enzyme was not associated with any plasmid, and production was not transferred to Escherichia coli K-12 recipients, even after the mobilizing plasmid pUZ8 was inserted into the S. marcecens donor strains.
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PMID:Biochemical characterization of a beta-lactamase that hydrolyzes penems and carbapenems from two Serratia marcescens isolates. 219 18

A multiple trauma patient failed treatment with ceftazidime and amikacin for bacteremia and meningitis due to a Klebsiella pneumoniae strain that produced a novel, plasmid-mediated beta-lactamase. Both pre- and posttreatment isolates were resistant to ceftazidime (MIC, greater than or equal to 64 micrograms/ml) and various penicillins but not to other expanded-spectrum cephalosporins. The beta-lactamase had a pI of 5.25 and was encoded on a conjugal plasmid of approximately 150 kilobases. DNA hybridization studies indicated that the enzyme was a TEM derivative.
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PMID:Failure of ceftazidime-amikacin therapy for bacteremia and meningitis due to Klebsiella pneumoniae producing an extended-spectrum beta-lactamase. 220 6


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