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PubMed1999

Genes specific for the biosynthesis of clavam metabolites antipodal to clavulanic acid are clustered with the gene for clavaminate synthase 1 in Streptomyces clavuligerus.

Portions of the Streptomyces clavuligerus chromosome flanking cas1, which encodes the clavaminate synthase 1 isoenzyme (CAS1), have been cloned and sequenced. Mutants of S. clavuligerus disrupted in cvm1, the open reading frame located immediately upstream of cas1, were constructed by a gene replacement procedure. Similar techniques were used to generate S. clavuligerus mutants carrying a deletion that encompassed portions of the two open reading frames, cvm4 and cvm5, located directly downstream of cas1. Both classes of mutants still produced clavulanic acid and cephamycin C but lost the ability to synthesize the antipodal clavam metabolites clavam-2-carboxylate, 2-hydroxymethyl-clavam, and 2-alanylclavam. These results suggested that cas1 is clustered with genes essential and specific for clavam metabolite biosynthesis. When a cas1 mutant of S. clavuligerus was constructed by gene replacement, it produced lower levels of both clavulanic acid and most of the antipodal clavams except for 2-alanylclavam. However, a double mutant of S. clavuligerus disrupted in both cas1 and cas2 produced neither clavulanic acid nor any of the antipodal clavams, including 2-alanylclavam. This outcome was consistent with the contribution of both CAS1 and CAS2 to a common pool of clavaminic acid that is shunted toward clavulanic acid and clavam metabolite biosynthesis.

Amino Acid Sequence↗
PubMedDate not supplied

Oral bioavailability of ampicillin and amoxycillin alone and bound in fixed proportions to sulbactam and clavulanic acid.

Oral bioavailability of ampicillin when bound to sulbactam (sultamicillin) compared with ampicillin alone and that of amoxycillin with a ligand of clavulanic acid versus amoxycillin alone were assessed in 16 healthy subjects using an open label, multiple crossover study. After a single administration of the drugs, the bioavailability of ampicillin released from sultamicillin was more than twice (2.17) that of ampicillin administered alone, whereas that of amoxycillin was increased by a factor of 1.64 by the presence of clavulanic acid. Higher peak concentrations and areas under the curves, along with shorter lag times, were observed in both cases. The increased oral bioavailability of these aminopenicillins when associated with a beta-lactamase inhibitor was well demonstrated in this study, the bioavailability of ampicillin being more enhanced by sulbactam than that of amoxycillin by clavulanic acid.

Administration, Oral↗
PubMed1997

A regulatory gene (ccaR) required for cephamycin and clavulanic acid production in Streptomyces clavuligerus: amplification results in overproduction of both beta-lactam compounds.

A regulatory gene (ccaR), located within the cephamycin gene cluster of Streptomyces clavuligerus, is linked to a gene (blp) encoding a protein similar to a beta-lactamase-inhibitory protein. Expression of ccaR is required for cephamycin and clavulanic acid biosynthesis in S. clavuligerus. The ccaR-encoded protein resembles the ActII-ORF4, RedD, AfsR, and DnrI regulatory proteins of other Streptomyces species, all of which share several motifs. Disruption of ccaR by targeted double recombination resulted in the loss of the ability to synthesize cephamycin and clavulanic acid. Complementation of the disrupted mutant with ccaR restored production of both secondary metabolites. ccaR was expressed as a monocistronic transcript at 24 and 48 h in S. clavuligerus cultures (preceding the phase of antibiotic accumulation), but no transcript hybridization signals were observed at 72 or 96 h. This expression pattern is consistent with those of regulatory proteins required for antibiotic biosynthesis. Amplification of ccaR in S. clavuligerus resulted in a two- to threefold increase in the production of cephamycin and clavulanic acid.

Amino Acid Sequence↗
PubMed1993

A semi-empirical study of some clavulanic acid derivatives in relation to their activity as beta-lactamase inhibitors.

Clavulanic acid and some of its derivatives are inhibitors of beta-lactamases and hence enhance the activity of antibiotics such as cephaloridine, amoxycillin and ampicillin against beta-lactamase-producing bacteria. Several empirical structure-activity relationships have been proposed for these compounds; bearing these findings in mind, we have carried out a semi-empirical structural study on clavulanic acid and twelve of its derivatives lacking the carboxyl group. We relate our results to the available activity data, focusing on features such as planarity at the N atom, charge distribution and the orientation of the substituents, all of which are related to the activity of these systems.

Clavulanic Acids↗
PubMed1992

In vitro antibacterial activities of ticarcillin alone and ticarcillin plus clavulanic acid against beta-lactamase producing and non-producing microorganisms.

A total of 818 clinical bacterial isolates were tested for the production of beta-lactamase by rapid chromogenic cephalosporin method and for the susceptibility to ticarcillin alone and in combination with clavulanic acid (2 micrograms/mL) by agar dilution method. These included 83 strains of methicillin-sensitive Staphylococcus aureus (MSSA), 31 of methicillin-resistant S. aureus (MRSA), 49 of Neisseria gonorrhoeae, 58 of Haemophilus influenzae, 112 of Escherichia coli, 118 of Klebsiella pneumoniae, 58 of Proteus mirabilis, 30 of Proteus vulgaris, 60 of Serratia marcescens, 113 of Enterobacter cloacae, 60 of Pseudomonas aeruginosa and 46 of Bacteroides fragilis. The results revealed that 46.6% of P. mirabilis, 53.4% of H. influenzae, 57.1% of N. gonorrhoeae, 80% of P. vulgaris, 83.9% of MRSA, 85.6% of MSSA, 87.5% of E. coli, 91.7% of S. marcescens, 95.7% of B. fragilis, 98.2% of E. cloacae, and 100% of K. pneumoniae and P. aeruginosa strains produced beta-lactamase. In general, beta-lactamase nonproducers were more susceptible to ticarcillin than beta-lactamase producers. The ranges of minimum inhibitory concentrations (MICs) of ticarcillin for beta-lactamase nonproducers of MSSA, MRSA, H. influenzae, E. coli, P. vulgaris, S. marcescens, E. cloacae, B. fragilis and beta-lactamase producers of MSSA, H. influenzae strains were all within the in vitro susceptible range. The presence of clavulanic acid resulted in a significant enhancement of the antibacterial activity of ticarcillin against beta-lactamase producers of MRSA, N. gonorrhoeae, E. coli, K. pneumoniae, P. mirabilis, P. vulgaris and B. fragilis strains. Clavulanic acid had no synergistic activity for ticarcillin against S. marcescens, P. aeruginosa and E. cloacae.

Bacteria↗
PubMed1990

Amoxicillin-clavulanic acid therapy of spontaneous bacterial peritonitis: a prospective study of twenty-seven cases in cirrhotic patients.

Spontaneous bacterial peritonitis in cirrhosis is a serious complication that demands urgent attention. We report here a prospective study of the treatment of 27 episodes of spontaneous bacterial peritonitis in 22 cirrhotic patients with amoxicillin and clavulanic acid. The infection of ascitic fluid was diagnosed by a positive culture plus an ascitic neutrophil count exceeding 75/microliters, or by an ascitic neutrophil count exceeding 500/microliters. The infection was treated with 1 gm amoxicillin and 0.2 gm clavulanic acid every 6 hr for 14 days. In 17 cases (63%), bacteria were isolated from the ascitic fluid. All the bacteria isolated were sensitive to amoxicillin and clavulanic acid, whereas in five cases they were resistant to amoxicillin alone (Escherichia coli in two cases, Klebsiella pneumoniae in two cases and Bacteroides fragilis in one case). Cure of the infection was achieved in 23 episodes (85%) after 14 days' treatment; 17 patients (63%) were able to leave the hospital. Fourteen of 20 patients (70%) treated for the first episode of infection died within 1 yr: eight from infection, two from gastrointestinal hemorrhage, one from infection and hemorrhage and three from tumors. One patient who had repeated infections underwent liver transplantation and has not had any infectious complications 1.5 yr after surgery. Amoxicillin and clavulanic acid may be an effective first-line therapy for ascitic fluid infection in cirrhosis. Nevertheless, the 1-yr prognosis continues to be grave and the severity of the underlying liver disease remains the most important determinant for survival.

Adult↗
PubMed1999

Integron- and carbenicillinase-mediated reduced susceptibility to amoxicillin-clavulanic acid in isolates of multidrug-resistant Salmonella enterica serotype typhimurium DT104 from French patients.

Fifty-seven Salmonella enterica serotype Typhimurium (S. typhimurium) isolates were collected from human patients in two French hospitals, Hôpital Antoine Béclère (Clamart, France) and Hôpital Bicêtre (Le Kremlin-Bicêtre, France), between 1996 and 1997. Thirty of them (52 percent) were resistant to amino-, carbeni-, and ureidopenicillins, had reduced susceptibility to amoxicillin-clavulanic acid, were susceptible to cephalothin, and were resistant to sulfonamides, streptomycin, chloramphenicol, and tetracyclines. All these strains possessed a blaPSE-1-like gene and were of phage type DT104. Ten of them were studied in more detail, which revealed that blaPSE-1 is located on the variable region of a class 1 integron. This integron was found to be chromosomally located, as was another class 1 integron containing aadA2, a streptomycin-spectinomycin resistance gene. The reduced susceptibility to amoxicillin-clavulanic acid (and to ticarcillin-clavulanic acid) may result from the high level of hydrolysis of the beta-lactam rather than to the clavulanic acid resistance properties of PSE-1 in these clonally related S. typhimurium isolates.

Amoxicillin-Potassium Clavulanate Combination↗
PubMed1991

[Bactericidal effect of cefadroxil, amoxicillin alone or in combination with clavulanic acid in sera of healthy volunteers].

Determination of minimal inhibitory concentrations (MICs) provides data on the susceptibility or resistance of a bacteria; however, in susceptible bacteria this parameter is not predictive of effectiveness of the antimicrobial agent. Bactericidal activities of cefadroxil, of amoxicillin, and of the amoxicillin-clavulanic acid combination on bacteria commonly found in ENT and lower respiratory tract disease were studied comparatively. The antibiotics were given by the oral route to six healthy volunteers. With beta-lactamase-producing and non-beta-lactamase-producing strains of Escherichia coli, amoxicillin produced MICs consistent with susceptibility but failed to exhibit a bactericidal effect, whereas cefadroxil was bactericidal. Combination of amoxicillin with an inhibitor did not modify this activity on E. coli and failed to produce a bactericidal effect on Klebsiella pneumoniae similar to that seen with cefadroxil. Amoxicillin with and without clavulanic acid exhibited comparable effectiveness on Streptococcus pyogenes and S. Pneumoniae. The bactericidal effect of cefadroxil on S. pneumoniae was of similar magnitude but shorter duration than that of amoxicillin. Cefadroxil and the amoxicillin-clavulanic acid combination had similar bactericidal effects against Staphylococcus aureus. These antibiotics exhibited a time-dependent effect on Gram positive microorganisms. These pharmacodynamic data, together with measures of bactericidal activity, may be very helpful for selecting the appropriate antibiotic and dosage.

Amoxicillin↗
PubMed1997

Abnormal physiological properties and altered cell wall composition in Streptococcus pneumoniae grown in the presence of clavulanic acid.

Subinhibitory concentrations of clavulanate caused premature induction of stationary-phase autolysis, sensitization to lysozyme, and reductions in the MICs of deoxycholate and penicillin for Streptococcus pneumoniae. In the range of clavulanate concentrations producing these effects, this beta-lactam compound was selectively bound to PBP 3. Cell walls isolated from pneumococci grown in the presence of clavulanate showed increased sensitivity to the hydrolytic action of purified pneumococcal autolysin in vitro. High-performance liquid chromatography analysis of the peptidoglycan isolated from the clavulanate-grown cells showed major qualitative and quantitative changes in stem peptide composition, the most striking feature of which was the accumulation of peptide species carrying intact D-alanyl-D-alanine residues at the carboxy termini. The altered biological and biochemical properties of the clavulanate-grown pneumococci appear to be the consequences of suppressed D,D-carboxypeptidase activity.

Amino Acid Sequence↗
PubMed1990

[Cholestatic hepatitis induced by the amoxicillin-clavulanic acid combination. A case and review of the literature].

We report the case of a patient who developed jaundice after receiving amoxicillin-clavulanic acid for 7 days. Laboratory features were consistent with acute cholestatic hepatitis. Histopathological examination of a liver specimen showed cholestasis. Complete recovery occurred within 2 months after withdrawal of the drug. Analysis of the 24 reported cases of amoxicillin-clavulanic acid induced hepatitis revealed a predominantly cholestatic syndrome occurring soon after drug administration. In all cases, hepatic dysfunction disappeared within 1 to 3 months after discontinuation of the drug. Because of the small number of cases in contrast with the widespread use of this drug, associated with blood hypereosinophilia or eosinophilic infiltration of portal triads in some cases, a hypersensitivity phenomenon is suggested.

Amoxicillin↗
PubMed2005

Beta-lactamase inhibition with clavulanic acid supplementing standard amoxycillin-based triple therapy does not increase Helicobacter pylori eradication rate.

BACKGROUND: Antibiotic resistance is the main reason of failure for H. pylori eradication and beta-lactamases produced by resistant H. pylori strains is a possible mechanism underlying ineffectiveness of an amoxycillin-based triple therapy. AIM: To investigate the benefit of using clavulanic acid associated with amoxycillin compared with amoxycillin alone in a standard triple therapy. METHODS: A total 172 H. pylori-positive dyspeptic patients were randomised to a daily treatment with esomeprazole (20 mg bid), clarithromycin (500 mg bid) and either amoxycillin plus clavulanic acid (1 g bid) or amoxycillin (1 g bid) alone for 1 week. H. pylori status was defined by histology and urea breath test at entry and following 8 weeks from the end of therapy by urea breath test and antigen faecal assessment. RESULTS: At intention-to-treat and per-protocol analysis eradication rates achieved by amoxycillin plus clavulanic acid (72 and 78%) were higher, but not significantly, than those achieved by amoxycillin alone triple therapy (62 and 72%). Compliance was good, side-effects mild and with a similar incidence in both regimens. CONCLUSIONS: Clavulanic acid supplemented to amoxycillin-based standard triple therapy does not significantly increase the H. pylori eradication rate with standard triple therapy.

Amoxicillin↗
PubMed1996

Cefuroxime compared to amoxicillin-clavulanic acid in the treatment of community-acquired pneumonia.

The study compared the efficacy and safety of cefuroxime (CFX) versus amoxicillin-clavulanic acid (AC) in the treatment of community-acquired pneumonia. A total of 48 patients (mean age 44 years; 32 males and 16 females) were randomised to receive sequential intravenous/oral CFX (750 mg i.v. 8H for 48 H/500 mg p.o bid) and sequential intravenous/oral AC (1.2 g i.v. 8 H for 48 H/ 750 mg p.o. tid) for 7-14 days. The two groups were well matched for age, sex and treatment duration (median 7 days). The most frequent causative organisms were Mycoplasma (3), Klebsiella species (2), Pseudomonas aeruginosa (2) and hemolytic streptococcus (2). clinical cure was obtained in 20 patients (83.3%) and 18 patients (75%) of CFX and AC group respectively. Clinical improvement was observed in one patient of the CFX group. There were 3 failures in the CFX group and 4 failures in the AC group. Two patients in the AC group developed adverse drug reactions (namely vomiting and rash) and were withdrawn from the study. In conclusion, cefuroxime and amoxicillin-clavulanic acid have comparable efficacy and safety in the treatment of community-acquired pneumonia.

Administration, Oral↗
PubMed1995

[Acute pancreatitis associated with hepatotoxicity induced by amoxicillin-clavulanic acid].

A 25-year old man suffered from acute pancreatitis and cholestatic acute hepatitis simultaneously after 4 weeks of an antibiotic treatment withdrawal (amoxicillin plus clavulanic acid) which was given for pharyngitis. Other potential etiological causes of both acute pancreatitis and liver disease, were excluded. The causal relationship between amoxicillin plus clavulanic acid and cholestatic hepatitis is well know, but no data has been reported regarding acute pancreatitis. The medical literature is reviewed and the mechanisms of toxicity are discussed.

Acute Disease↗
PubMed1988

[Evaluation of the biliary excretion of a ticarcillin-clavulanic acid combination in man].

The association of a beta-lactamase inhibitor, clavulanic acid (CA) (0.2 g) to ticarcillin (TIC) (3 g) enhances the activity of the latter on resistant strains. The aim of the present study was to assess their biliary elimination in man. Serum, urine and bile concentrations of TIC and CA were measured in biological samples collected in 10 cholecystectomized patients provided with a T-tube, during 12 hours after the IV administration of 3.2 g of claventin. Concerning TIC, a mean biliary peak of 177 +/- 49 (SEM) micrograms/ml was reached during the 2nd hour; the total biliary output (0-12 h) (AB) was 8.8 +/- 2.6 mg (0.28% of the administered dose), the hepato-biliary clearance CL HB 0.34 ml/min and the biological half-life, TB 1/2 1.2 h. The mean biliary peak of CA was 2.7 +/- 0.5 micrograms/ml and occurred during the first hour. AB amounted to 98.5 +/- 34.7 micrograms (0.04% of dose), CLHB to 0.10 ml/min and TB 1/2 1.2 h. In per-operatively sampled serum, choledochal bile, gallbladder bile and gall-bladder wall, the following concentrations were measured 1 hour after the IV administration of 3.2 g of Claventin. TIC: 105 +/- 11; 386 +/- 66; 72 +/- 20 micrograms/ml and 36 +/- 11 micrograms/g. CA: 3.6 +/- 0.7; 5.9 +/- 1.5; 0.3 +/- 0.3 micrograms/ml and 0.1 +/- 0.1 micrograms/g. The biliary pharmacokinetic profiles allow to favorably consider the prophylactic use of Claventin in the surgery of the biliary tract as well as its therapeutic administration in biliary tract infections.

Adult↗
PubMed2005

Using redox potential to detect microbial activities during clavulanic acid biosynthesis in Streptomyces clavuligerus.

Production of clavulanic acid (CA) by Streptomyces clavuligerus in a shake-flask culture increased from 92 to 180 mg l(-1) with an increased O2 transfer efficiency (0.039 --> 0.058 s(-1)), which maintained the redox potential values above -250 mV. Compared with traditional measures, such as dissolved O2 concentration and respiratory activity, the redox potential can easily be determined and correlates closely with CA production. It can therefore be used to monitor microbial activities during biosyntheses of secondary metabolites.

Bioreactors↗
PubMed1995

Treatment of community-acquired pneumonia: a randomized comparison of sparfloxacin, amoxycillin-clavulanic acid and erythromycin.

The treatment of community-acquired pneumonia is empirical in most cases and must cover a wide range of potential pathogens, such as Streptococcus pneumoniae, including penicillin-resistant strains, Haemophilus influenzae and intracellular microorganisms. The objective of this double-blind, randomized, parallel group study was to compare the efficacy and safety of sparfloxacin (400 mg loading dose, followed by 200 mg o.d.) with that of oral amoxycillin-clavulanic acid (500/125 mg t.i.d.) or oral erythromycin (1 g b.i.d.), during 7-14 days in 808 patients with confirmed community-acquired pneumonia. The overall success rates for sparfloxacin (87%), amoxycillin-clavulanic acid (80%) and erythromycin (85%) were similar in evaluable patients, and the equivalence hypothesis used for the statistical analysis showed at least an equivalent efficacy for the three antibiotics tested. The analysis of microbiologically documented infections (40% of the patients) showed that overall success rates were similar for S. pneumoniae and H. influenzae infections. Treatment withdrawal was necessary in 3.5, 2.5 and 7.7% of the patients treated with sparfloxacin, amoxycillin-clavulanic acid and erythromycin, respectively. This study indicates that sparfloxacin was at least as effective as amoxycillin-clavulanic acid or erythromycin in the treatment of mild-to-moderate community-acquired pneumonia and that the adverse effects were similar in the three groups.

Adolescent↗
PubMed1985

In vitro susceptibility of Campylobacter jejuni to 27 antimicrobial agents and various combinations of beta-lactams with clavulanic acid or sulbactam.

The in vitro susceptibility of human isolates of Campylobacter jejuni was investigated with 27 antibiotics and 8 combinations of beta-lactams with clavulanic acid or sulbactam. Ansamycin, the new quinolines, erythromycin, and cefpirome were the most active drugs against C. jejuni; amoxicillin, ampicillin, cefotaxime, and ceftazidime 90% of the isolates, greater than or equal to 50 mg/liter). The activity of various beta-lactams was unchanged by the addition of clavulanic acid or sulbactam.

Anti-Bacterial Agents↗
PubMed1994

Cloning, sequencing and disruption of a gene from Streptomyces clavuligerus involved in clavulanic acid biosynthesis.

During the purification of delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine synthetase (ACVS) from Streptomyces clavuligerus, a small protein (CLA) involved in clavulanic acid production co-purified with ACVS. A 24-mer mixed-DNA probe based on the N-terminal amino-acid sequence of CLA was used to isolate the corresponding gene (cla), located near one end of the known cluster of penicillin and cephamycin biosynthetic genes, 5.7 kb downstream from the pcbC gene which encodes isopenicillin-N synthase. The sequence of cla would encode a protein of 313 aa with a high degree of similarity to amidinohydrolase enzymes. The cla gene is located immediately upstream from the previously described clavaminate synthase 2-encoding gene (cs2), and cla homologs were only present in streptomycetes which produced clavam compounds. Replacement of cla with a disrupted copy of the gene blocked the production of clavulanic acid in starch asparagine medium (SA).

Amino Acid Sequence↗