Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Clavulanic Acids”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1985

Augmentation effect of clavulanic acid with penicillin, cephalothin and ticarcillin against Bacteroides fragilis.

The effect of clavulanic acid on the in vitro activity of beta-lactam antibiotics against Bacteroides fragilis (154 strains) was tested. The MIC90 on 154 strains of B. fragilis tested was greater than 64 micrograms/ml for penicillin and cephalothin, and greater than 128 for ticarcillin alone. 32 strains of B. fragilis relatively resistant to the test beta-lactam antibiotics (most of them beta-lactamase producers) were retested with the addition of clavulanic acid. 90% of the strains were then inhibited by less than or equal to 8 micrograms/ml of penicillin and cephalothin, and by 32 micrograms/ml of ticarcillin. The strongest beta-lactamase producers were the most susceptible, and this was not influenced by change in pH of the diluent for clavulanic acid from 6.0 to 7.4. Both penicillin and cephalothin when combined with clavulanic acid were highly effective against B. fragilis but the therapeutic relevance of these combinations remains to be evaluated.

Bacteroides fragilis↗
PubMed1988

The effects of clavulanic acid and sulbactam on beta-lactamase biosynthesis.

Clavulanic acid and sulbactam were tested as inducers of beta-lactamase in 21 strains of Gram-negative bacteria. beta-Lactamase synthesis was inducible in all these strains, as demonstrated by the increased enzyme activities obtained when cells were grown in the presence of 10 mg/l of cefoxitin, the increase varying from 11- to 734-fold However, at the same concentration, neither inhibitor induced significant amounts of beta-lactamase, except in one strain of Providencia rettgeri, where both were potent inducers. When steps were taken to overcome the inhibitory effects of clavulanic acid and sulbactam, they were still found to be ineffective inducers. We conclude that, at therapeutic concentrations, clavulanic acid and sulbactam are generally poor inducers of beta-lactamase. Amoxycillin and ampicillin induced more beta-lactamase than the inhibitors, but were much less effective than cefoxitin, except for the strain of Prov. rettgeri.

Clavulanic Acids↗
PubMed1988

Pharmacokinetics of intravenously and intramuscularly administered ticarcillin and clavulanic acid in foals.

Serum concentrations of ticarcillin and clavulanic acid were measured in healthy foals (2 to 6 months old) given the drugs in combination by intravenous and intramuscular routes of administration. Five foals were administered 50 mg of ticarcillin/kg of body weight and 1.67 mg of clavulanic acid/kg, IV. Five foals were administered 100 mg of ticarcillin/kg and 3.33 mg of clavulanic acid/kg, IV, and 4 of those 5 were given the same combined dose IM. The elimination half-life of ticarcillin for intravenous administration was 0.83 hour for the low dosage and 0.96 hour for the high dosage. After intramuscular administration, the half-life of elimination was 2.9 hours, with bioavailability of 54.6%. For IV administered clavulanic acid, the elimination half-life was 0.65 hour for the low dosage and 0.74 hour for the high dosage. After intramuscular administration, the elimination half-life was 0.92 hour, and bioavailability was 68.1%. A combined dosage, 50 mg of ticarcillin/kg and 1.67 mg of clavulanic acid/kg, given every 6 hours is recommended.

Animals↗
PubMed1985

A controlled study of ticarcillin plus clavulanic acid versus piperacillin as empiric therapy for fever in the immunocompromised host.

Clavulanic acid, a potent beta-lactamase inhibitor, was studied in fixed combination with ticarcillin and used with tobramycin as empiric therapy for fever in the immunocompromised host. Fifty febrile episodes were evaluated in patients with hematologic malignancy and/or neutropenia. Eighty-one percent of evaluable infections treated with the study regimen of ticarcillin, clavulanic acid, and tobramycin responded. Seventy-four percent of evaluable infections treated with the control regimen of piperacillin, tobramycin, and vancomycin responded (p = 0.4). Resistance to piperacillin and ticarcillin were noted in 23.8 percent of 21 isolated organisms. Resistance to ticarcillin and clavulanic acid was noted in only one (4.7 percent) of the isolated organisms (p = 0.092). Untoward reactions, including rash, nephrotoxicity, and superinfection, were unusual and occurred with equal frequency in the study and control groups. Clavulanic acid in combination with ticarcillin was effective and safe in treating fever in the immunocompromised host.

Bacterial Infections↗
PubMed2004

Simultaneous determination of cefatrizine and clavulanic acid in dog plasma by HPLC.

A rapid and specific high-performance liquid chromatographic method was developed and validated for the simultaneous determination of cefatrizine and clavulanic acid in the plasma of beagle dog. The sample pretreatment procedure involved reaction of clavulanic acid with 1,2,4-triazole, which readily produced a derivative with its maximum UV absorption at 314 nm. This derivative was separated in a reverse-phase C-18 column without being interfered by other components present in plasma. Cefatrizine, however, was not derivatized and, therefore determined directly at 269 nm. Sulfanilamide was used as an internal standard. The retention times of sulfanilamide, the derivative, and cefatrizine were, 3.5, 4.9, and 6.0 min, respectively. The assay showed linearity from 2 to 100 microg/ml for cefatrizine and from 1 to 50 microg/ml for clavulanic acid. Precision expressed as R.S.D. ranged from 4.2 to 18.2% for cefatrizine and 5.5 to 15.8% for clavulanic acid. Accuracy ranged from 97.9 to 120% (lower limit of quantitation) for cefatrizine and from 97.7 to 119.2% for clavulanic acid. Extraction efficiencies for cefatrizine, clavulanic acid, and internal standard from dog plasma averaged 79.8+/-5.8%, 84.8+/-6.2%, and 89.0+/-3.8%, respectively. This method was employed successfully to follow the time course of the concentration of cefatrizine and clavulanic acid in beagle dogs following oral administration of cefatrizine and clavulanic acid.

Administration, Oral↗
PubMed1993

In-vitro evaluation of the four beta-lactamase inhibitors: BRL42715, clavulanic acid, sulbactam, and tazobactam.

The in-vitro synergic activities of BRL42715, a new beta-lactamase inhibitor, clavulanic acid, sulbactam, and tazobactam combined with ampicillin, piperacillin, cephalothin, or cefoperazone were tested against various bacteria producing known types of beta-lactamase. BRL42715 showed the best synergistic activity among the inhibitors tested against strains producing penicillinases of type I, II, III, V, and that from Klebsiella pneumoniae, cephalosporinases, and oxyiminocephalosporinases (except that from Klebsiella oxytoca). Clavulanic acid combined with the beta-lactams tested showed the best synergic activity of the inhibitors against strains producing type IV penicillinase and oxyiminocephalosporinase from K. oxytoca. The 50% inhibitory doses of BRL42715 were superior to those of clavulanic acid against various types of beta-lactamases except for type IV penicillinase and the oxyiminocephalosporinase from K. oxytoca. The inhibitory activity of BRL42715 against cephalosporinases from various bacteria was 10(4) to 10(6)-fold greater than that of clavulanic acid. The synergic effects of BRL42715 and clavulanic acid on the activity of piperacillin were compared against six clinical isolates of bacteria resistant to piperacillin. The synergic activity of BRL42715 was greater than that of clavulanic acid in all six isolates.

Anti-Bacterial Agents↗
PubMed1985

Effect of clavulanic acid on inactivated amoxicillin excretion in urinary tract infection.

Oral amoxicillin was taken with and without clavulanic acid by normal subjects and by patients with chronic complicated urinary tract infection to examine the in vitro protective effect of clavulanic acid on amoxicillin degradation. When amoxicillin alone was taken, urinary excretion of the penicilloic acid of amoxicillin in bacteria-positive patients was higher than that in bacteria-negative patients and in normal subjects. There was no comparable change in urinary penicilloic acid excretion in the presence of clavulanic acid. There were significant in vitro protective effects of clavulanic acid on beta-lactamases in the urine.

Administration, Oral↗
PubMed1991

Evaluation of acrylic strips containing amoxycillin with clavulanic acid for local drug delivery.

The in vitro release of amoxycillin with clavulanic acid from acrylic strips at initial concentrations of 30, 40 and 50 per cent w/w was monitored using a double-beam ultraviolet spectrophotometer and compared with release of tetracycline hydrochloride. Highest levels of the antibacterial agents were released during the first 24 h period. Therapeutic levels of the drugs continued to be released during the subsequent 9 day period and were shown to be biologically active. Furthermore, for amoxycillin with clavulanic acid, an initial concentration of 40 per cent gave the highest level of release on day 10; while, for tetracycline, 50 per cent provided the highest level of release. Local application of 40 per cent amoxycillin with clavulanic acid incorporated into acrylic strips placed in periodontal pockets in patients with established periodontitis produced a marked change in the subgingival microflora as monitored by dark-field microscopy and cultural techniques. These changes in the subgingival flora were concomitant with elimination of bleeding on probing at the treated sites and were still evident 3 weeks after removal of the acrylic strips. The sensitivity of Bacteroides gingivalis (syn. Porphyromonas gingivalis) and Bacteroides intermedius (syn. Prevotella intermedia) isolated before and after treatment to amoxycillin with clavulanic acid remained unchanged.

Acrylic Resins↗
PubMed2006

An rplKDelta29-PALG-32 mutation leads to reduced expression of the regulatory genes ccaR and claR and very low transcription of the ceaS2 gene for clavulanic acid biosynthesis in Streptomyces clavuligerus.

The transcriptional and translational control of the biosynthesis of the beta-lactamase inhibitor clavulanic acid is a subject of great scientific and industrial interest. To study the role of the ribosomal protein L11 on control of clavulanic acid gene transcription, the DNA region aspC-tRNA(trp)-secE-rplK-rplA-rplJ-rplL of Streptomyces clavuligerus was cloned and characterized. An S. clavuligerus rplK(DeltaPALG) mutant, with an internal 12 nucleotides in-frame deletion in the rplK gene, encoding the L11 (RplK) ribosomal protein lacking amino acids (29)PALG(32), was constructed by gene replacement. This deletion alters the L11 N-terminal domain that interacts with the RelA and class I releasing factors-mediated translational termination. The mutant grew well, showed threefold higher resistance to thiostrepton, did not form spores and lacked diffusible brown pigments, as compared with the wild-type strain. The wild-type phenotype was recovered by complementation with the native rplK gene. S. clavuligerus rplK(DeltaPALG) produced reduced levels of clavulanic acid (15-26% as compared with the wild type) and cephamycin C (40-50%) in cultures grown in defined SA and complex TSB media. The decreased yields resulted from an impaired transcription of the regulatory genes ccaR and claR and the cefD and ceaS2 genes for cephamycin and clavulanic acid biosynthesis respectively. Expression of ceaS2 encoding carboxyethylarginine synthase (CEAS), the precursor-committing enzyme for clavulanic acid biosynthesis, was particularly affected in this mutant. In the wild-type strain polyphosphorylated nucleotides peaked at 36-48 h of growth in SA cultures whereas expression of the cephamycin and clavulanic acid genes occurred 12-24 h earlier than the increase in ppGpp indicating that there is no strict correlation between the peak of ppGpp and the onset of transcription of the clavulanic acid and cephamycin C biosynthesis. The drastic effect of the rplK(DeltaPALG) mutation on the onset of expression of the ceaS2 and the regulatory ccaR and claR genes and the lack of correlation with ppGpp levels suggest that the onset of transcription of these genes is modulated by the conformational alteration of the N-terminal region of L11 probably by interaction with the nascent peptide releasing factors and with RelA.

Amino Acids↗
PubMed2004

Two oligopeptide-permease-encoding genes in the clavulanic acid cluster of Streptomyces clavuligerus are essential for production of the beta-lactamase inhibitor.

orf7 (oppA1) and orf15 (oppA2) are located 8 kb apart in the clavulanic acid gene cluster of Streptomyces clavuligerus and encode proteins which are 48.0% identical. These proteins show sequence similarity to periplasmic oligopeptide-binding proteins. Mutant S. clavuligerus oppA1::acc, disrupted in oppA1, lacks clavulanic acid production. Clavulanic acid production is restored by transformation with plasmid pIJ699-oppA1, which carries oppA1, but not with the multicopy plasmid pIJ699-oppA2, which carries oppA2. The mutant S. clavuligerus oppA2::aph also lacks clavulanic acid production, shows a bald phenotype, and overproduces holomycin (5). Clavulanic acid production at low levels is restored in the oppA2-disrupted mutants by transformation with plasmid pIJ699-oppA2, but it is not complemented by the multicopy plasmid pIJ699-oppA1. Both genes encode oligopeptide permeases with different substrate specificities. The disrupted S. clavuligerus oppA2::aph is not able to grow on RPPGFSPFR (Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg; bradykinin), but both mutants grow on VAPG (Val-Ala-Pro-Gly) as the only nitrogen source, indicating differences in the peptide bound by the proteins encoded by both genes. The null S. clavuligerus oppA1::acc and S. clavuligerus oppA2::aph mutants are more resistant to the toxic tripeptide phosphinothricyl-alanyl-alanine (also named bialaphos) than the wild-type strain, suggesting that this peptide might be transported by these peptide-binding proteins.

Amino Acid Sequence↗
PubMed1985

Treatment of infections in hospitalized patients with ticarcillin plus clavulanic acid. A comparative study.

Ninety patients at the Wilmington Medical Center were enrolled in a comparative study to evaluate the efficacy and toxicity of ticarcillin plus clavulanic acid in the treatment of a variety of infections. Forty-seven women with obstetric or gynecologic infections were randomly assigned to receive ticarcillin plus clavulanic acid or cefoxitin. Forty-three patients with gram-negative septicemia or lower respiratory tract infection were given ticarcillin plus clavulanic acid or tobramycin plus piperacillin in a randomized fashion. Of the 47 women with obstetric or gynecologic infections, 23 were randomly assigned to receive ticarcillin plus clavulanic acid, and 24 were randomly assigned to receive cefoxitin. Several patients in each group had underlying diseases such as diabetes, obesity, and hypertension. Of the 27 pathogens isolated in the group receiving ticarcillin plus clavulanic acid, 26 (96 percent) were eradicated, including all three ticarcillin-resistant pathogens. In the cefoxitin-treated group, 31 of the 33 (94 percent) pathogens were eliminated, including all four ticarcillin-resistant organisms. Three reinfections or superinfections occurred, and cefoxitin therapy failed to eliminate an enterococcus isolate from the endometrium in one patient. The clinical response in both treatment groups was excellent. Either cure or clinical improvement was achieved for all 18 sites of infection in the ticarcillin plus clavulanic acid-treated group and for all 22 sites in the cefoxitin-treated group. There were no systemic drug reactions in either treatment group. In one patient in the cefoxitin-treated group, local phlebitis developed at the infusion site. This reaction responded to local therapy. There were no local reactions among the patients receiving ticarcillin plus clavulanic acid. Of the 43 patients with gram-negative septicemia or lower respiratory tract infection, 21 were randomly assigned to receive ticarcillin plus clavulanic acid and 22 were assigned to receive tobramycin plus piperacillin. Thirty-six patients had gram-negative sepsis, and seven patients had lower respiratory tract infection. Nine of the 36 patients suspected of having gram-negative sepsis were not evaluable because no pathogen was isolated prior to treatment. Twenty-two of the 27 patients treated for septicemia had good clinical and microbiologic responses. Three of the seven patients with pneumonia were not evaluable. Of the four evaluable patients, two had pneumococcus pneumonia; one was treated with tobramycin plus piperacillin and one with ticarcillin plus clavulanic acid. In both instances, the clinical and bacteriologic responses were considered good.

Adolescent↗
PubMed1999

Deletion of the pyc gene blocks clavulanic acid biosynthesis except in glycerol-containing medium: evidence for two different genes in formation of the C3 unit.

The beta-lactamase inhibitor clavulanic acid is formed by condensation of a pyruvate-derived C3 unit with a molecule of arginine. A gene (pyc, for pyruvate converting) located upstream of the bls gene in the clavulanic acid gene cluster of Streptomyces clavuligerus encodes a 582-amino-acid protein with domains recognizing pyruvate and thiamine pyrophosphate that shows 29.9% identity to acetohydroxyacid synthases. Amplification of the pyc gene resulted in an earlier onset and higher production of clavulanic acid. Replacement of the pyc gene with the aph gene did not cause isoleucine-valine auxotrophy in the mutant. The pyc replacement mutant did not produce clavulanic acid in starch-asparagine (SA) or in Trypticase soy broth (TSB) complex medium, suggesting that the pyc gene product is involved in the conversion of pyruvate into the C3 unit of clavulanic acid. However, the beta-lactamase inhibitor was still formed at the same level as in the wild-type strain in defined medium containing D-glycerol, glutamic acid, and proline (GSPG medium) as confirmed by high-pressure liquid chromatography and paper chromatography. The production of clavulanic acid by the replacement mutant was dependent on addition of glycerol to the medium, and glycerol-free GSPG medium did not support clavulanic acid biosynthesis, suggesting that an alternative gene product catalyzes the incorporation of glycerol into clavulanic acid in the absence of the Pyc protein. The pyc replacement mutant overproduces cephamycin.

Acetolactate Synthase↗
PubMed1991

The activity of amoxicillin plus clavulanic acid against Mycobacterium leprae in mice.

The activity of amoxicillin plus clavulanic acid against logarithmically multiplying Mycobacterium leprae was evaluated by treating mice by gavage five times weekly with various amounts of the compound from day 60 to day 150 after footpad infection. At 25, 50, and 100 mg/kg, it was inactive; at 200-600 mg/kg, multiplication of M. leprae was entirely prevented for 6-11 months after drug discontinuation, consistent with observations of bactericidal activity for M. leprae. In a confirmatory study in mice, five-times-weekly intraperitoneal ticarcillin plus clavulanic acid, 1000 mg/kg, was not bactericidal for M. leprae, while amoxicillin plus clavulanic acid, 400 mg/kg five times weekly, was weakly bactericidal (80% +/- 14%). In addition, activity of amoxicillin plus clavulanic acid, 400 mg/kg, was evaluated in combination with previously established active drugs dapsone, 0.0001% (in diet), rifampin, 20 mg/kg monthly (by gavage), and kanamycin, 25 mg/kg five times weekly (intraperitoneally). All three combinations were active, and the combination with kanamycin was more active than either drug alone.

Amoxicillin↗
PubMed1981

Interaction of beta-lactamase of Streptomyces cacaoi. I. Clavulanic acid and PS-5.

Inactivation of a beta-lactamase of Streptomyces cacaoi by clavulanic acid and PS-5 was investigated and compared with that of a beta-lactamase of Bacillus cereus. Inhibition of the enzymes induced by clavulanic acid and the beta-lactam antibiotic PS-5 was found to be progressive with time. However, the degree of inhibition of the beta-lactamase from S. cacaoi increased more progressively with time than that of the enzyme from B. cereus. Conformative response constants were determined. As compared with clavulanic acid, over ten times higher concentrations of PS-5 were necessary to give a similar degree of inhibition. At lower concentrations, both clavulanic acid and PS-5 behaved as competitive inhibitors. Ki values calculated from the integrated form of the LINEWEAVER-BURK type were 1.1 X 10(-7) M and 7.6 X 10(-6) M for clavulanic acid and PS-5, respectively.

Anti-Bacterial Agents↗
PubMed2002

Oligomeric structure of proclavaminic acid amidino hydrolase: evolution of a hydrolytic enzyme in clavulanic acid biosynthesis.

During biosynthesis of the clinically used beta-lactamase inhibitor clavulanic acid, one of the three steps catalysed by clavaminic acid synthase is separated from the other two by a step catalysed by proclavaminic acid amidino hydrolase (PAH), in which the guanidino group of an intermediate is hydrolysed to give proclavaminic acid and urea. PAH shows considerable sequence homology with the primary metabolic arginases, which hydrolyse arginine to ornithine and urea, but does not accept arginine as a substrate. Like other members of the bacterial sub-family of arginases, PAH is hexameric in solution and requires Mn2+ ions for activity. Other metal ions, including Co2+, can substitute for Mn2+. Two new substrates for PAH were identified, N-acetyl-(L)-arginine and (3R)-hydroxy-N-acetyl-(L)-arginine. Crystal structures of PAH from Streptomyces clavuligerus (at 1.75 A and 2.45 A resolution, where 1 A=0.1 nm) imply how it binds beta-lactams rather than the amino acid substrate of the arginases from which it evolved. The structures also suggest how PAH selects for a particular alcohol intermediate in the clavam biosynthesis pathway. As observed for the arginases, each PAH monomer consists of a core of beta-strands surrounded by alpha-helices, and its active site contains a di-Mn2+ centre with a bridging water molecule responsible for hydrolytic attack on to the guanidino group of the substrate. Comparison of structures obtained under different conditions reveals different conformations of a flexible loop, which must move to allow substrate binding.

Amino Acid Sequence↗
PubMed1985

Comparative study of amoxicillin-clavulanic acid and cephalexin in the treatment of bacteriuria during pregnancy.

A comparative clinical trial of amoxicillin-clavulanic acid and cephalexin was carried out in 80 women with bacteriuria of pregnancy. Treatment was randomly allocated and consisted of either one tablet of amoxicillin plus clavulanic acid (250 and 125 mg, respectively) three times daily or cephalexin (250 mg) three times daily for 7 days. Overall bacteriological cure rates at 2 weeks were 77% in the amoxicillin-clavulanic acid group and 74% in the cephalexin group. At 6 weeks the respective rates were 76 and 60%. Twenty-five episodes of infection were with ampicillin-resistant strains; cure rates were 82% (2 weeks) and 80% (6 weeks) in the amoxicillin-clavulanic acid group and 85 and 64%, respectively, in the cephalexin group. Differences in cure rates were not statistically significant. No significant difference in the rate of side effects was found. In particular, no toxicity to the fetus was seen which could be ascribed to either drug. Amoxicillin-clavulanic acid would appear to be a safe and effective treatment for bacteriuria of pregnancy.

Amoxicillin↗
PubMed1995

Susceptibilities of nontuberculosis mycobacterial species to amoxicillin-clavulanic acid alone and in combination with antimycobacterial agents.

Neither amoxicillin nor clavulanic acid used alone was active at the highest level tested, i.e., 256.0 micrograms/ml, in vitro against 24 isolates of Mycobacterium fortuitum, Mycobacterium kansasii, and Mycobacterium marinum. However, the MIC of an amoxicillin-clavulanic acid combination of 2:1 was < or = 8.0/4.0 micrograms/ml for 50 percent of the isolates tested, with all isolates being inhibited in the range of 4.0/2.0 to 32.0/16.0 micrograms/ml, respectively. Titration of amoxicillin-clavulanic acid with a fixed 2-micrograms/ml concentration of ethambutol resulted in synergistic activity against 3 of 9 isolates of M. fortuitum, 10 of 10 isolates of M. kansasii, and 5 of 5 isolates of M. marinum. This observation was confirmed in a checkerboard analysis in which fractional inhibitory concentrations were < or = 0.5 for 20 of the 24 isolates. Synergistic activity was observed against the other four isolates in one of two trials. On the other hand, titration of amoxicillin-clavulanic acid in the presence of either one or two fixed concentrations of isoniazid, rifampin, cycloserine, tetracycline, or amikacin failed to result in synergism.

Amoxicillin↗
PubMed1995

[Amoxicillin and clavulanic acid versus amoxicillin plus gentamicin in the empirical initial treatment of urinary tract infections in hospitalized patients].

We compared the fixed combination amoxicillin plus clavulanic acid with that of amoxicillin plus gentamicin in the empirical initial treatment of severe urinary tract infections. The study included 87 hospitalized patients (51 women and 36 men, mean age 58 +/- 22 years) with acute uncomplicated pyelonephritis (n = 48) or with complicated urinary tract infections (n = 39). 80 patients (92%) had fever and 31 patients (36%) positive blood cultures. 45 patients were randomly assigned to amoxicillin plus clavulanic acid and 42 to amoxicillin plus gentamicin. Overall, 18 patients (21%) were infected with organisms resistant in vitro to amoxicillin plus clavulanic acid, whereas no pathogen was isolated with resistance to amoxicillin plus gentamicin (p < 0.0001). At the end of the empirical treatment (4.2 +/- 1.5 days after the start), significant bacteriuria was present in 6/39 patients (15%) assigned to amoxicillin plus clavulanic acid, compared to 0/34 patients assigned to amoxicillin plus gentamicin (p < 0.05). The clinical response was satisfactory in both groups, and the time from start of therapy to resolution of fever was 2.2 +/- 1.4 days in the amoxicillin plus clavulanic acid group and 2.3 +/- 1.7 days in the amoxicillin plus gentamicin group. Although the in-vitro resistance did not result in a lower clinical efficacy of amoxicillin plus clavulanic acid compared to amoxicillin plus gentamicin in our relatively small sample of patients, the data indicate that the antimicrobial activity of amoxicillin plus clavulanic acid is inadequate to cover the spectrum of causative agents in hospitalized patients with pyelonephritis or complicated urinary tract infections. Amoxicillin plus clavulanic acid should therefore not be used in the initial empirical treatment of these infections.

Adult↗