Antibacterial activity of ticarcillin in the presence of clavulanate potassium.

The antibacterial effects produced by ticarcillin disodium plus clavulanate potassium, a combination of the broad-spectrum penicillin ticarcillin, and the beta-lactamase inhibitor clavulanic acid as the potassium salt, have been measured in vitro and in experimental infection studies. The presence of clavulanic acid resulted in a significant enhancement of the activity of ticarcillin against a wide range of beta-lactamase-producing bacteria. These included ticarcillin-resistant strains of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, P. vulgaris, Yersinia enterocolitica, and the anaerobe Bacteroides fragilis. In addition, beta-lactamase-producing isolates of Hemophilus influenzae, Branhamella catarrhalis, Neisseria gonorrhoeae, and Staphylococcus aureus were susceptible to ticarcillin and clavulanate. Clavulanic acid did not influence the activity of ticarcillin against ticarcillin-susceptible bacteria. The bactericidal effects of the antibiotic combination were measured in an in vitro kinetic model in which the drug concentrations were varied to simulate those measured in humans after intravenous dosing with ticarcillin (3.0 g) and clavulanate potassium (100 mg clavulanic acid). In these tests, ticarcillin plus clavulanic acid had pronounced bactericidal activity against ticarcillin-resistant bacteria. The protection of ticarcillin by clavulanic acid from inactivation by bacterial beta-lactamases in vivo was demonstrated in experimental infection models in which the efficacy of the ticarcillin plus clavulanic acid combination against infections caused by beta-lactamase-producing bacteria was correlated with the presence of effective concentrations of both antibiotic and inhibitor at the site of infection.

Famciclovir treatment of chronic hepatitis B in heart transplant recipients: a prospective trial.

UNLABELLED: Hepatitis B may take a rapid and aggressive course in patients under immunosuppression. Nucleoside analogues have been shown to suppress viral replication effectively. To investigate the effect of famciclovir in immunosuppressed patients, 21 heart transplant recipients with chronic hepatitis B infection were included in a prospective study. PATIENTS AND METHODS: Patients have been treated with Famciclovir for a median of 14 months. Hepatitis B virus replication and biochemical parameters were regularly tested and liver biopsies were taken before treatment and after a median time of 7 months. HBV-polymerase was sequenced in all patients before therapy and in those patients who experienced virological breakthrough. RESULTS: Nineteen patients were treated for at least 6 months. Hepatitis B virus-DNA levels declined in all patients and became negative in 8 patients. Mean hepatitis B virus-DNA levels decreased from 199+/-269 to 34+/-53 pg/ml after 24 weeks (P=0.003). During treatment HBeAg became negative in five patients. Mean alanine aminotransferase decreased from 42+/-26 to 24+/-10 U/L (P=0.006). Histological analysis revealed improved inflammatory activity according to the Ishak-score in 11/16 (69%) patients. Total inflammatory activity scores decreased from 8 to 6 (median, NS), but interface hepatitis score (P=0.02) and lobular inflammation score (P=0.006) improved significantly. Median fibrosis scores fell from 5 to 3 (P=0.002). Three patients developed virological breakthrough on famciclovir after 7, 8, and 26 months of treatment showing HBV-polymerase amino acid changes L528 M, S567A, and I581K, respectively. CONCLUSIONS: Famciclovir improves not only biochemical and virological features but also hepatic inflammation and liver fibrosis in patients with chronic hepatitis B under heavy immunosuppression. Virological breakthrough may develop and requires close monitoring.

Temocillin. In vitro antibacterial activity.

Temocillin, a 6-alpha-methoxy penicillin derivative, was tested in vitro against 516 recent clinical isolates of Enterobacteriaceae. The compound exhibited good antibacterial activity, with 95% of isolates inhibited by a range 2 to 16 mg/L. Further studies, against selected isolates resistant to ticarcillin, piperacillin and cefuroxime (Klebsiella oxytoca, 25; Enterobacter species, 34; and Citrobacter species, 5), showed about half of the isolates of K. oxytoca (11/25) to be resistant to aztreonam (MIC range 16-greater than or equal to 128 mg/L), but susceptible to temocillin, cefotaxime and latamoxef. In general, the resistant strains of Enterobacter species tested were not susceptible to cefotaxime (MIC range 16-128 mg/L), or aztreonam (MIC range 1.0-64 mg/L), and many exhibited reduced susceptibility to latamoxef (MIC range 2-128 mg/L). In contrast, all the strains were susceptible to temocillin (MIC range 4-16 mg/L). The bactericidal activity of temocillin was confirmed against selected aztreonam-resistant strains of K. oxytoca and Enterobacter cloacae by conventional time-kill studies, and against a strain of E. cloacae in an in vitro model system designed to simulate the temocillin concentration profiles attained in extravascular fluid such as peripheral lymph. In the time-kill studies, temocillin concentrations of 16 and 32 mg/L were shown to effectively reduce the numbers of viable bacteria by 99 and 99.9%, respectively, within 12 hours. In the in vitro model system the numbers of bacteria were reduced 99.9% over the initial 4-hour period. In combination with aminoglycoside antibiotics, temocillin exerted a synergistic or partially synergistic effect (sigma FIC less than or equal to 0.75) against the majority of strains of Pseudomonas aeruginosa tested. When combined with piperacillin, cefotaxime or latamoxef, temocillin, unlike cefoxitin, exhibited no antagonism against strains of Enterobacteriaceae producing inducible cephalosporinases.

Use of Mahalonobis generalized distance in interpreting low-resolution gas-chromatographic profiles of urinary steroids.

We used low-resolution gas-chromatography of urinary steroid metabolites, as their trimethylsilyl ethers, in conjunction with the Mahalonobis generalized distance to assess the analyses in terms of a multivariate normal distribution in two populations of women: 18-50 years old and older. We compare the use of this method of interpretation, presenting several cases to illustrate the use of this approach in a routine clinical chemistry laboratory. The improved accuracy of classification as abnormals and to the ability to identify an analysis result as abnormal, even when values for all the analyses fall within the univariate 95% regions of each constituent.

Antibacterial activity of resolved temocillin epimers.

The antibacterial activity of pure resolved R and S epimers of temocillin was determined in a variety of in-vitro test systems, including those that allowed measurement of activity during the early period following exposure to the agents, thus minimising the effect of epimerization. In conventional agar- and broth-dilution susceptibility tests involving incubation at 37 degrees C for 18 h, little difference was evident between the activities of the individual epimers. In contrast, in other tests of antibacterial activity, such as time-kill and turbidimetric studies, the R epimer and temocillin (R/S mixture 1.8:1.0) were shown to be more rapidly bactericidal than the S epimer. Overall, the R epimer and temocillin (R/S) exhibited a similar degree of bactericidal activity in vitro.

Antibacterial activity of mupirocin (pseudomonic acid), a new antibiotic for topical use.

Mupirocin (pseudomonic acid A), an antibiotic produced by Pseudomonas fluorescens, showed a high level of activity against staphylococci and streptococci and against certain gram-negative bacteria, including Haemophilus influenzae and Neisseria gonorrhoeae, but was much less active against most gram-negative bacilli an anaerobes. Nearly all clinical isolates of Staphylococcus aureus and Staphylococcus epidermidis, including multiply resistant strains, were susceptible (mupirocin MIC, less than or equal to 0.5 microgram/ml). There was no cross-resistance between mupirocin and clinically available antibiotics, and the selection of resistant variants in vitro occurred at a low frequency. Mupirocin was highly bound (95% bound) to the protein of human serum, and activity was reduced 10- to 20-fold in the presence of human serum. The activity of mupirocin was not greatly influenced by inoculum size but was significantly enhanced in acid medium. In tests of bactericidal activity, MBCs were 8- to 32-fold higher than MICs and the antibiotic demonstrated a slow bactericidal action in time-kill tests, resulting in 90 to 99% killing after 24 h at 37 degrees C.

Relevance of increased serum thyroxine concentrations associated with normal serum triiodothyronine values in hypothyroid patients receiving thyroxine: a case for "tissue thyrotoxicosis".

Fifteen patients receiving standard thyroxine replacement therapy (100-200 micrograms daily) for primary hypothyroidism and who had persistently raised free thyroxine concentrations in their serum were investigated to see whether the dose being given was too high. In addition to the usual thyroid hormone assays systolic time intervals (which indicate left ventricular contractility) were calculated as accurate reflectors of tissue thyroid activity. All patients showed the expected increased free and total thyroxine concentrations; but mean total and free concentrations of triiodothyronine were normal, while reverse triiodothyronine values were raised. Mean systolic time intervals were significantly reduced as compared with normal and fell within the thyrotoxic range. Seven patients subsequently had their doses of thyroxine reduced by 50 micrograms daily and were reinvestigated one month later. All showed significant falls in circulating thyroxine and triiodothyronine concentrations and an increase in mean systolic time intervals to the normal range. In patients receiving thyroxine replacement therapy for primary hypothyroidism a raised serum thyroxine concentration may indicate tissue thyrotoxicosis and should prompt a reduction of the thyroxine dose.

Famciclovir treatment of hepatitis B infection following liver transplantation: a long-term, multi-centre study.

Famciclovir is a novel guanosine nucleoside analogue with activity against herpes viruses and hepatitis B virus (HBV). Several preliminary reports have described efficacy of famciclovir in patients with recurrent hepatitis B after orthotopic liver transplantation (OLT). This report describes the largest study to date of long-term famciclovir treatment in patients with de novo or recurrent hepatitis B post-OLT. One hundred thirty patients with detectable serum HBV DNA after OLT received oral famciclovir 500 mg tid on a compassionate-use basis. Safety analyses included all treated patients; efficacy was assessed in all patients and a subgroup of 73 patients with complete baseline HBV DNA and alanine aminotransferase (ALT) data who had received > or =6 months of treatment. Efficacy parameters included serum levels of HBV DNA, ALT, and anti-HBe or anti-HBs seroconversion rates. Of the 70 patients treated for > or =6 months who could be evaluated for response/non-response to famciclovir, 52 (74%) were responders, defined as patients who experienced a 70% decrease or more in HBV DNA levels from baseline, or who became HBV DNA-negative, for at least two consecutive visits. In famciclovir responders, HBV DNA levels decreased by a median of 91% after 12 weeks of treatment, 95% after 6 months and >99% after 18 months of treatment. Marked differentiation between responders and non-responders could be made soon after the onset of treatment. Among anti-HBe positive patients with evidence of HBV replication, 12/13 were responders. Patients with high baseline ALT levels experienced more rapid suppression of HBV DNA during therapy with famciclovir. Famciclovir therapy was safe and well tolerated; serious adverse events were reported infrequently. Famciclovir treatment may be beneficial in patients with hepatitis B infection post-OLT.