Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The in vitro activities of the newer semisynthetic penicillins azlocillin, mezlocillin, and piperacillin were compared with those of ampicillin and ticarcillin by using 290 clinical laboratory isolates. Piperacillin and mezlocillin were the most active against Escherichia coli, Proteus mirabilis, Klebsiella spp., and Enterobacter spp. When Pseudomonas aeruginosa was tested, piperacillin and azlocillin were more active than either mezlocillin or ticarcillin. Streptococcus pneumoniae and Haemophilus influenzae species were highly susceptible to all of the penicillins tested. Ticarcillin had relatively poor activity against enterococci. The rate of bacterial killing with multiples of the minimal inhibitory concentration of azlocillin, ampicillin, or ticarcillin was tested for E. coli, P. mirabilis, P. aeruginosa, and Klebsiella spp. Increasing concentrations increased the bactericidal effect. The effect of combining azlocillin, ampicillin, or ticarcillin with an aminoglycoside was studied by using both killing curves and checkerboards. The isobolograms constructed from the checkerboards showed a synergistic pattern for the organisms tested, which included E. coli, P. aeruginosa, Klebsiella spp., P. mirabilis, and enterococci. However, the rate of killing was increased by the combination only for P. aeruginosa and enterococci.
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PMID:Comparative in vitro activity of azlocillin, ampicillin, mezlocillin, piperacillin, and ticarcillin, alone and in combination with an aminoglycoside. 11 16

The in vitro activity of piperacillin (T-1220), a new semisynthetic derivative of aminobenzylpenicillin, was investigated. The majority of streptococci and pneumococci were inhibited by 0.12 micrograms/ml; the staphylococci and enterococci were inhibited by 2 micrograms/ml. Piperacillin was slightly more active against Neisseria and Haemophilus influenzae than was ampicillin. Piperacillin was active against all members of the Enterobacteriaceae including the Klebsiella, 58% of which were inhibited by 8 micrograms/ml. The activity of piperacillin was at least equivalent, but generally superior, to that of ampicillin or carbenicillin on species susceptible to these drugs. Most striking was its activity on Pseudomonas aeruginosa: 50% were inhibited by 2 micrograms/ml, and 83% were inhibited by 4 micrograms/ml. The minimum bactericidal concentrations were very close to the minimum inhibitory concentrations, and in most species only a slight inoculum effect was observed on the minimum bacterial values except for certain P. aeruginosa strains. A complete parallel resistance exists between piperacillin and ampicillin or carbenicillin. However, the clinical importance of this is largely mitigated by the intrinsically higher activity of piperacillin.
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PMID:In vitro activity of piperacillin, a new semisynthetic penicillin with an unusually broad spectrum of activity. 12 18

The in vitro activity of piperacillin, a new semisynthetic piperazine penicillin derivative, was evaluated against 626 clinical isolates and compared with the activity of other beta-lactam antibiotics. At a concentration of 0.1 microgram/ml, piperacillin inhibited all streptococci except enterococci. Non-beta-lactamase-producing staphylococci were inhibited by 1.6 microgram or less per ml. Both beta-lactamase- and non-beta-lactamase-producing Haemophilus were inhibited by 0.1 microgram/ml. Piperacillin inhibited non-beta-lactamase-producing Escherichia coli, Salmonella, and Shigella at a concentration of 6.3 micrograms/ml, but 20% of strains of these species containing type III beta-lactamase were not inhibited by 100 micrograms/ml. Piperacillin at 25 micrograms/ml, inhibited 83% of Citrobacter, 58% of Klebsiella, 88% of Enterobacter, and 50% of indole-positive Proteus, Acinetobacter, and Providencia. At 25 micrograms/ml, piperacillin inhibited 95% of Pseudomonas aeruginosa and 78% of Bacteroides fragilis. The minimal inhibitory concentration of piperacillin against Pseudomonas was affected by increasing the inoculum size and by pH. Minimum bactericidal concentrations against Pseudomonas and Serratia often were eightfold greater than the minimum inhibitory concentrations. Piperacillin was equal in activity to ampicillin against enterococci. It was more active than carbenicillin against E. coli, Klebsiella, Enterobacter, and Bacteroides. It was the most active penicillin against Pseudomonas and inhibited many strains of Pseudomonas for which the MICs of carbenicillin were above 200 micrograms/ml. Piperacillin was hydrolyzed by many different beta-lactamases. Synergistic activity of piperacillin was demonstrated when it was combined with amikacin, gentamicin, and cefazolin against P. aeruginosa and members of the Enterobacteriaceae. No antagonism was observed when piperacillin was combined with aminoglycosides; however, antagonism was observed rarely against E. coli when piperacillin was combined with cefazolin.
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PMID:Piperacillin, a new penicillin active against many bacteria resistant to other penicillins. 12 19

The in vitro activities of the new ureidopenicillins piperacillin, mezlocillin, azlocillin, and Bay k 4999 were compared with those of ampicillin and ticarcillin against 336 Enterobacteriaceae, 109 nonfermenters, 55 Neisseria, and 28 Haemophilus influenzae isolates. Bay k 4999 displayed the largest spectrum of activity and had lower minimal inhibitory concentrations than any of the other penicillins against all of the species tested. Piperacillin showed the same spectrum but was slightly less active than Bay k 4999; it was slightly more effective than mezlocillin against Enterobacteriaceae and fully as active as azlocillin against Pseudomonas. All ureidopenicillins were substantially more active than ampicillin and ticarcillin. Isolates highly resistant to ampicillin or ticarcillin were also less susceptible to the ureidopenicillins.
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PMID:Comparison of the activities of the new ureidopenicillins piperacillin, mezlocillin, azlocillin, and Bay k 4999 against gram-negative organisms. 48 23

The in vitro activities of ticarcillin, piperacillin, clavulanic acid, tazobactam, ticarcillin-clavulanate, and piperacillin-tazobactam against 819 bacterial isolates were compared. The two beta-lactamase inhibitors, clavulanic acid and tazobactam, had little useful antibacterial activity but enhanced the activities of the penicillins against beta-lactamase-producing strains of Haemophilus influenzae, Branhamella catarrhalis, and methicillin-susceptible Staphylococcus aureus; all strains were susceptible to both combinations. Both enzyme inhibitors also enhanced the activities of the penicillins against most strains of Escherichia coli, Klebsiella spp., Citrobacter diversus, Proteus spp., Providencia spp., and Bacteroides spp. and against occasional strains of Citrobacter freundii, Enterobacter spp., and Serratia marcescens. Clavulanic acid frequently enhanced the activity of ticarcillin against Xanthomonas maltophilia, and tazobactam frequently enhanced the activity of piperacillin against Morganella morganii. Enhancement was observed primarily with strains relatively resistant to the penicillins. In general, clavulanic acid was more effective than tazobactam in enhancing penicillin activity against Klebsiella spp., C. diversus, X. maltophilia, and Bacteroides spp., whereas tazobactam was more effective against Escherichia coli and Proteeae. There was little or no enhancement of activity against Enterococcus faecalis, Aeromonas hydrophila, Pseudomonas aeruginosa, Pseudomonas cepacia, or Acinetobacter anitratus. Clavulanic acid occasionally antagonized the activity of ticarcillin against ticarcillin-susceptible members of the family Enterobacteriaceae, but those strains were still considered susceptible to the combination. Tazobactam never antagonized the activity of piperacillin. In a direct comparison of the activities of ticarcillin-clavulanate and piperacillin-tazobactam, the two were equally active against H. influenzae, B. catarrhalis, and S. aureus; the latter was more active against E. faecalis. For relatively susceptible strains of members of the family Enterobacteriaceae, neither combination was predictably more active than the other, but relatively resistant strains were generally more susceptible to piperacillin-tazobactam. Piperacillin-tazobactam was more active than ticarcillin-clavulanate against A. hydrophila, P. aeruginosa, and P. cepacia, similar in activity against A. anitratus, and less active against X. maltophilia and Bacteroides spp.
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PMID:Comparative in vitro activities of piperacillin-tazobactam and ticarcillin-clavulanate. 255 4

The combination of piperacillin and the beta-lactamase inhibitor tazobactam (formerly YTR 830) was studied to determine optimal disk concentrations and dilution testing conditions. In addition, the potency of the combination was compared to that of piperacillin alone. The spectrum of piperacillin was greatly expanded by the addition to tazobactam principally against beta-lactamase producing strains of Haemophilus influenzae, Escherichia coli, Morganella morganii, Proteus vulgaris, Providencia stuartii, Shigella spp., Neisseria gonorrhoeae, and Staphylococcus spp. Tazobactam was active alone against Branhamella catarrhalis (minimum inhibitory concentration [MIC] 50, less than or equal to 1 microgram/ml), gonococci (MIC 50, 0.5-4 micrograms/ml), and N. meningitidis (MIC 50, less than or equal to 1 microgram/ml). Studies with beta-lactamase-producing type strains showed tazobactam to have high affinity for plasmid-mediated enzymes (TEM-1 and 2, SHV-1, HMS-1, and some CARB or OXA types) and not chromosomal beta-lactamases. Piperacillin/tazobactam inhibited 93% of fluoro-quinolone resistant strains at less than or equal to 64/8 micrograms/ml but failed to suppress the growth of 15 strains producing stably depressed cephalosporinases. Comparisons of piperacillin/tazobactam results determined with 100/10-, 100/20-, and 100/30-micrograms disks established the 100/10-micrograms disk as most usable. Among five different MIC combinations the ratio of eight parts piperacillin to one part tazobactam or fixed concentration tests at greater than or equal to 4 micrograms tazobactam/ml were preferred, each producing very low occurrences (less than or equal to 1.6%) of false-resistance or -susceptibility when compared to disk test results. MICs determined by agar and broth microdilution methods were essentially the same. The recommended breakpoints for piperacillin/tazobactam MICs were identical to those now found in the NCCLS susceptibility testing standards with the following exceptions: (1) for tests with H. influenzae and Staphylococcus spp.--susceptible at greater than or equal to 21 mm (MIC less than or equal to 16/2 micrograms/ml) and resistant less than or equal to 20 mm (MIC less or equal to 32/4 micrograms/ml); and (2) all remaining nonspeudomonas isolates would be interpreted by the NCCLS piperacillin enteric bacilli susceptibility criteria. This newer beta-lactamase inhibitor combination appears to be worthy of further in vivo trials guided by these or similar tentative in vitro susceptibility testing parameters.
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PMID:Studies to optimize the in vitro testing of piperacillin combined with tazobactam (YTR 830). 256 Apr 22

A review of clinical studies of piperacillin shows that it is valuable for the treatment of respiratory infections due to Enterobacteriaceae, Pseudomonas sp, anaerobes, and mixed flora including anaerobes. Various studies of a total of 420 patients treated with piperacillin for lower respiratory tract infections found that 97% of the patients were cured or markedly improved. Piperacillin has also been found as effective as combination therapy (gentamicin or tobramycin plus carbenicillin or ticarcillin) in the treatment of serious infections, including pneumonia and several caused by gram-negative organisms and anaerobic organisms. A review of the literature on bacteriological responses to piperacillin shows that 126 of 153 (82%) of the susceptible strains could be eradicated. Streptococcus pneumoniae, beta-hemolytic streptococci, Haemophilus influenzae, Peptostreptococcus sp, Bacteroides sp, and Fusobacterium sp have been completely eradicated by treatment with piperacillin. Most of the published studies indicate that therapy with the drug is usually well tolerated.
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PMID:Respiratory infections: clinical evaluation. 390 45

Three new broad-spectrum penicillins--azlocillin, mezlocillin, and piperacillin--will soon be available for clinical use. Azlocillin and piperacillin are more active than carbenicillin or ticarcillin against Pseudomonas aeruginosa. Piperacillin and mezlocillin demonstrate significant activity against the Enterobacteriaceae, including many strains of Klebsiella pneumoniae against which the older penicillins carbenicillin, ticarcillin, and ampicillin are ineffective. All three new drugs show substantial activity against anaerobes and ampicillin-susceptible gonococci and Haemophilus influenzae. Because these agents are inactivated by various beta-lactamases, most Staphylococcus aureus isolates and a number of gram-negative organisms, including some important nosocomial pathogens, will be resistant to these antibiotics. The new penicillins appear to be relatively safe and have been used successfully to treat patients with various infections; however, comparative trials have not yet established the superiority of these drugs over conventional therapeutic agents.
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PMID:Azlocillin, mezlocillin, and piperacillin: new broad-spectrum penicillins. 621 72

The in-vitro activity of ticarcillin in combination with clavulanic acid was compared with that of ticarcillin alone, piperacillin, cefotaxime and, where appropriate, other beta-lactams against a total of 301 recent clinical isolates and characterized beta-lactamase producers. An agar dilution procedure was used to determine MICs and two inocula (10(4) and 10(6) cfu) were used throughout. MICs of the combination of ticarcillin and clavulanic acid were expressed as MICs of ticarcillin in the presence of 5 or 10 mg/l of clavulanic acid. Against most members of the Enterobacteriaceae (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Providencia stuartii and Serratia marcescens), ticarcillin plus clavulanic acid was as active as or more active than piperacillin. Against Staphylococcus aureus. Haemophilus influenzae and the Bacteroides fragilis group the combination was considerably more active than piperacillin. Piperacillin was more active than the ticarcillin/clavulanic acid combination against Pseudomonas aeruginosa.
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PMID:Clavulanic acid in combination with ticarcillin: an in-vitro comparison with other beta-lactams. 632 75

Piperacillin was evaluated in vitro against 711 clinical isolates of aerobic and anerobic gram-positive and gram-negative bacteria, including 76 isolates of Salmonella typhi. Piperacillin minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were compared with those of a range of beta-lactam, aminoglycoside, and other antimicrobial agents, and inoculum size effects were considered. The relationship between dilution and disk diffusion tests was studied by regression analysis. In addition, piperacillin was assessed in combination with aminoglycoside and other beta-lactam drugs. This investigation has confirmed the activity of piperacillin against a broad range of bacteria, including Pseudomonas, Enterobacteriaceae, Neisseria, beta-lactamase-negative Haemophilus influenzae, and Staphylococcus aureus as well as enterococci, Bacteroides fragilis, and other anaerobes. All strains of Pseudomonas aeruginosa were inhibited by </=32 mug/ml or less, demonstrating again the potential usefulness of piperacillin in the treatment of pseudomonal infections. S. typhi proved susceptible to piperacillin, all isolates being inhibited by 1 mug/ml. Inoculum size experiments showed that inocula of 10(8) CFU resulted in MICs and MBCs appreciably higher than those resulting from inocula of 10(6) CFU, and inocula of 10(2) CFU resulted in MICs and MBCs appreciably lower than those resulting from inocula of 10(4) CFU. Piperacillin was active against all gentamicin-resistant pseudomonads tested, but not against gentamicin-resistant klebsiellas and enterobacters. Combinations of piperacillin with tobramycin and amikacin were consistently synergistic against Pseudomonas and Serratia isolates. Less consistent results were shown when piperacillin was combined with aminoglycosides or cephalothin against Klebsiella and indole-positive Proteus isolates, although synergy was observed in most cases. Occasional antagonistic reactions were encountered with piperacillin-cephalothin or piperacillin-tobramycin combinations against the latter isolates.
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PMID:Comparative in vitro appraisal of piperacillin, including its activity against Salmonella typhi. 644 3


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