Clinical evaluation of efficacy, pharmacokinetics, and safety of teicoplanin for serious gram-positive infections

Pharmacokinetics and pharmacodynamics of peptide antibiotics

Antimicrobial resistance is a major global health challenge. As few new efficacious antibiotics will become available in the near future, peptide antibiotics continue to be major therapeutic options for treating infections caused by multidrug-resistant pathogens. Rational use of antibiotics requires optimisation of the pharmacokinetics and pharmacodynamics for the treatment of different types of infections. Toxicodynamics must also be considered to improve the safety of antibiotic use and, where appropriate, to guide therapeutic drug monitoring. This review focuses on the pharmacokinetics/pharmacodynamics/toxicodynamics of peptide antibiotics against multidrug-resistant Gram-negative and Gram-positive pathogens. Optimising antibiotic exposure at the infection site is essential for improving their efficacy and minimising emergence of resistance.

Treatment of Infection and Colonization Caused by Methicillin-Resistant Staphylococcus aureus

The mechanism of methicillin resistance confers resistance to all available B-lactam antibiotics; consequently, B-lactam antibiotics have no role in therapy of methicillin-resistant Staphylococcus aureus (MRSA) infections. Vancomycin remains the drug of choice. Teicoplanin and daptomycin are two investigational antibiotics related to vancomycin in structure and in spectrum of activity. In clinical trials employing relatively low doses, neither was as effective as vancomycin. Trials at higher doses are on-going. Quinolones, ciprofloxacin in particular, have been used successfully to treat infections caused by MRSA; however, the usefulness of quinolones may be limited by the tendency of resistance to emerge during therapy. Quinolones probably should be used only in combination with another active agent, such as rifampin, when treating serious infections caused by MRSA. Other agents may be active in vitro against MRSA, but clinical data showing their effectiveness are lacking. Rifampin combination regimens appear most effectively to eradicate colonization with MRSA.

Effects of teicoplanin on cell number of cultured cell lines

Teicoplanin is a glycopeptide antibiotic with a wide variation in human serum half-life. It is also a valuable alternative of vancomycin. There is however no study on its effect on cultured cells. The aim of the present study was to test the effect of teicoplanin on cultured cell lines CHO, Jurkat E6.1 and MCF-7. The cultured cells were exposed to teicoplanin at final concentrations of 0-11000 μg/ml for 24 hours. To determine cell viability, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test was performed. At low concentrations of teicoplanin the numbers of cultured cells (due to cell proliferation) were increased in the three cell lines examined. The maximum cell proliferation rates were observed at concentrations of 1000, 400, and 200 μg/ml of teicoplanin for CHO, MCF-7 and Jurkat cell lines, respectively. Cell toxicity was observed at final concentrations over 2000, 6000, and 400 μg/ml of teicoplanin for CHO, MCF-7 and Jurkat cell lines, respectively. A dose-dependent manner of cell toxicity was observed. Our present findings indicated that teicoplanin at clinically used concentrations induced cell proliferation. It should therefore be used cautiously, particularly in children, pregnant women and patients with cancer.

Recommended initial loading dose of teicoplanin, established by therapeutic drug monitoring, and outcome in terms of optimal trough level

Teicoplanin has a long serum half-life, and therefore it takes time to reach a steady-state concentration. An initial loading procedure has been recommended for teicoplanin to enable prompt reaching of the optimal serum trough level (10-15 microg/ml). However, the dose of teicoplanin that should be administered to patients with varying renal function levels remains inconclusive. In this study, we monitored the serum concentrations of teicoplanin in patients with methicillin-resistant Staphylococcus aureus (MRSA) pneumonia and compared different teicoplanin serum concentrations and their clinical efficacy, investigating the significance of the mean dose administered during the initial 3 days. The study included 48 patients with MRSA pneumonia. The peak and trough concentrations of teicoplanin were determined utilizing a fluorescence polarization immunoassay and a two-compartment Bayesian population model. Teicoplanin was given at a loading dose of 400 or 800 mg on the first day, followed by maintenance doses of 200 or 400 mg. The mean initial dose (MID) over the first 3 days was calculated as: (loading dose + dose on 2nd day + dose on 3rd day)/3. Patients with an MID of 266.7 mg or less (400 mg for loading, 200 mg over the 2nd and 3rd days) did not have a trough level that exceeded 10 microg/ml at the point before the injection on the 4th day. Even in patients with hemodialysis (HD), an MID of 266.7 mg was not enough to provide a trough level of 10 microg/ml. Patients with an MID than 533.3 mg had significantly elevated trough levels, showing better outcomes. A multiple regression formula for predicting trough level before the fourth day of administration is given as: 0.034 + 0.030 x (MID; mg) - 0.057 x creatinine clearance (Ccr; ml/min). These findings suggest that 800 mg as an initial dose, followed by 400 mg maintenance doses over the following 2 days, makes it possible to safely attain an optimal trough level, even in the patients with HD.

Synergistic activity of vancomycin and teicoplanin alone and in combination with streptomycin against Enterococcus faecalis strains with various vancomycin susceptibilities

The synergy between two glycopeptides, vancomycin (Vm) and teicoplanin (Tec) and streptomycin (Sm) was studied by time-kill method. Five clinical vanB resistant Enterococcus faecalis (ENC) isolates with variable Vm-susceptibility were used. Different concentrations of Vm, Tec and Sm representing therapeutic concentrations were combined. Antibacterial activity was related to the concentrations of Vm and Sm, and Vm susceptibility to ENC. For strains with Vm MIC up to 64 mg/l, synergy was achieved with higher concentrations of Vm and Sm, while all combinations of Tec and Sm were synergistic against all strains except ENC 29. For ENC 29 with Vm MIC of 512 mg/l and Tec MIC of <1 mg/l, none of the combinations was synergistic. The significance of these in vitro results needs further investigation in vivo.

Clinical ototoxicity of teicoplanin

No strong evidence of ototoxicity of teicoplanin can be found in the literature, possibly because of conservative definitions of ototoxicity. We performed audiometry over time to compare the ototoxicity of teicoplanin with that of cloxacillin as a non-ototoxic standard. The data were analyzed with a linear mixed-effects model. The hearing thresholds of 12 patients who were treated with teicoplanin for severe staphylococcal infections showed a slight but significant increase over time, whereas the thresholds of 5 patients treated with cloxacillin decreased significantly during treatment. This improvement in hearing with cloxacillin may be attributed to improvement of the clinical condition. This outcome implies that previous reports that suggest a lack of ototoxicity of teicoplanin potentially underestimate the risk and should be interpreted accordingly.

Limitations of presently available glycopeptides in the treatment of Gram-positive infection

The glycopeptide antibacterial drugs vancomycin and teicoplanin are widely used in hospitals for therapy of severe or multiresistant Gram-positive infections, notably staphylococcal, enterococcal and rarely pneumococcal. Vancomycin has also been used in the management of Clostridium difficile enteropathy. The incidence and potential for resistance differ between agents. The in vitro activity, pharmacokinetics and clinical use of glycopeptide, as well as epidemiology of glycopeptide resistance are discussed. There are limited comparative studies indicating the need for further investigation. Therapeutic drug monitoring has been widely used for vancomycin and less commonly for teicoplanin, but remains controversial. Advances in our understanding of their pharmacodynamics and clinical studies are helping clarify the situation. This paper reviews the current literature and highlights limitations of glycopeptides in treating Gram-positive infection.

Comparative safety of teicoplanin and vancomycin

Teicoplanin have different safety profiles which can affect choice. Nephrotoxicity is significantly less likely to occur during treatment with teicoplanin than vancomycin when an aminoglycoside is being given concurrently. 'Red man' syndrome is a troublesome effect of vancomycin infusion which is extremely uncommon with teicoplanin use. Rash and fever can be dose-related phenomena but patients reacting to one glycopeptide may not react to both. Although thrombocytopenia is more frequent with teicoplanin, it is reversible and seldom seen at standard doses.

Protein binding and serum bactericidal activities of vancomycin and teicoplanin

In a randomized crossover study, the protein binding and serum bactericidal activities (SBAs) of vancomycin and teicoplanin against Staphylococcus aureus and Streptococcus pyogenes were investigated in six healthy volunteers. Total concentrations in serum 1 h postadministration of vancomycin and teicoplanin were 25.5 +/- 2.7 and 10.8 +/- 8.9 mg/liter, respectively; mean free concentrations were 14.6 +/- 2.0 and 0.6 +/- 0.9 mg/liter, respectively. Protein binding for vancomycin was 36.9% +/- 2.87%, and that for teicoplanin was 97.4% +/- 2.6%. SBA determined in pooled human serum at 1 h against S. aureus ranged from 1:8 to 1:32 for both vancomycin and teicoplanin. Against S. pyogenes SBA at 1 h ranged from 1:16 to 1:128 for vancomycin and 1:256 to 1:2,048 for teicoplanin. In vitro kill curve studies showed that vancomycin is slowly bactericidal and that teicoplanin is bacteriostatic. Despite having less in vitro cidal activity against the study isolates and having low or unrecordable levels of free drug in serum, teicoplanin demonstrated a similar or better SBA than vancomycin. SBA was more closely related to the total drug level (r = 0.77 for S. aureus and r = 0.79 for S. pyogenes) than the free level of teicoplanin (r = 0.59 for S. aureus and r = 0.56 for S. pyogenes). The high level of protein binding of teicoplanin did not seem to impair its antibacterial activity as measured by its SBA.

Right-sided endocarditis caused by Staphylococcus aureus in drug abusers

A prospective, open, and randomized study of right-sided endocarditis caused by Staphylococcus aureus in drug abuse patients is reported. The following parenteral treatments were compared. Group A patients were treated with 2 g of cloxacillin every 4 h and 1.5 mg of gentamicin per kg of body weight every 8 h for 2 weeks. Group B patients were treated with teicoplanin at 10 mg/kg/12 h on the 1st to 3rd days, 6 mg/kg/12 h on the 4th to 7th days, and 7 mg/kg/24 h on the 8th days. Drug abusers with bacteremia caused by S. aureus and suggestive signs of endocarditis were included. Clinical failures were observed in one patient in group A and in four of six patients in group B. Three patients in group B developed breakthrough bacteremia with teicoplanin-susceptible strains on days +6, +14, and +19. Serum teicoplanin levels and serum bactericidal titers showed a decrease in the 2nd week, when dosages received were 7 mg/kg/day. In conclusion, in treatment of right-sided endocarditis caused by S. aureus in drug abusers with teicoplanin, the use of dosages of 7 mg/kg/day is not recommended even if patients have received dosages of 12 mg/kg/day during the 1st week.

Treatment of cerebrospinal fluid shunt infections with teicoplanin

Intraventricular teicoplanin 10-15 mg was administered daily to three patients with cerebrospinal fluid (CSF) shunt infections due to Staphylococcus epidermidis and Enterococcus faecalis. Teicoplanin concentrations in CSF 24 h after intrathecal injection of the drug exceeded four- to eight-fold the MICs for the infecting microorganisms. CSF cultures rapidly became negative and shunt devices were withdrawn and replaced in the same operative procedure. Intraventricular teicoplanin was well tolerated. No relapses occurred. Teicoplanin may be an alternative to vancomycin for the antimicrobial therapy of CSF shunt infections.

Bactericidal activities of teicoplanin, vancomycin, and gentamicin alone and in combination against Staphylococcus aureus in an in vitro pharmacodynamic model of endocarditis

We adapted an in vitro pharmacodynamic model of infection to incorporate simulated endocardial vegetations. The bactericidal activities of teicoplanin, vancomycin, gentamicin, and various combinations of these drugs were studied against a strain of methicillin-susceptible Staphylococcus aureus obtained from a patient being treated for endocarditis at Detroit Receiving Hospital. Bacteria were grown overnight, concentrated, and added to a mixture of cryoprecipitate (80%) and thrombin (10%) to achieve approximately 5 x 10(9) CFU/g. Fibrin clots (8 to 10) were suspended into the model, removed at 24, 48, and 72 h in duplicate, weighed, and homogenized in 1.25% trypsin. Control experiments were conducted to characterize the growth kinetics. The following antibiotics were administered to simulate the pharmacokinetics of the drugs in humans: teicoplanin at 3 and 15 mg/kg of body weight, vancomycin at 15 mg/kg, and gentamicin at 1 mg/kg. Fibrin clot samples used to detect resistance were plated on antibiotic-containing tryptic soy agar plates. For the teicoplanin and vancomycin regimens, protein binding to cryoprecipitate, thrombin, and fibrin clot was determined to be 32, 43, and 50% and 26, 28, and 29%, respectively. In comparison with no treatment, vancomycin or teicoplanin at 15 mg/kg or either of these regimens combined with gentamicin significantly reduced bacterial counts (P < 0.0001). Monotherapy with teicoplanin at 3 mg/kg or gentamicin resulted in no killing activity. Combination treatment with teicoplanin at 3 mg/kg and gentamicin resulted in the killing of approximately 2 log10 CFU/g by 72 h and the development of resistance to gentamicin. The results obtained with the in vitro model of endocarditis are similar to the results reported by several investigators with the rabbit model of infective endocarditis. This unique infection model is useful for designing initial drug dosage regimens and may be predictive of drug efficacy against infective endocarditis.

Enhanced killing of methicillin-resistant Staphylococcus aureus in human macrophages by liposome-entrapped vancomycin and teicoplanin

The antibacterial effects of liposomal vancomycin and teicoplanin against intracellular methicillin-resistant Staphylococcus aureus (MRSA) were evaluated using a macrophage infection model. Human blood-derived monocytes were cultured for 7 days to obtain adherent macrophages. Uptake of each drug by macrophages was markedly enhanced by liposomal encapsulation. Following phagocytosis and removal of residual extracellular MRSA, the infected macrophages were exposed to clinically achievable concentrations of teicoplanin and vancomycin. The free (untrapped) and liposome-entrapped forms of each drug were used at the same concentration. The number of intracellular surviving bacteria was determined by colony counts after lysis of the macrophages at different time intervals following drug treatment. Intracellular antimicrobial effect of each drug was significantly (p < 0.001) increased by entrapment in liposomes. Also, the efficacies of the free and liposomal forms of both drugs were correspondingly comparable (p > 0.05). It is, therefore, concluded that liposomal encapsulation of vancomycin and teicoplanin results in an increased availability of the antibiotics for efficient elimination of intracellular MRSA infection.

Teicoplanin alone or combined with rifampin compared with vancomycin for prophylaxis and treatment of experimental foreign body infection by methicillin-resistant Staphylococcus aureus

The prophylactic and therapeutic activities of teicoplanin were evaluated in two different experimental models of foreign body infections caused by methicillin-resistant Staphylococcus aureus (MRSA). In a guinea pig model of prophylaxis, subcutaneously implanted tissue cages were infected at a > 90% rate by 10(2) CFU of MRSA in control animals. A single dose of 30 mg of teicoplanin per kg of body weight administered intraperitoneally 6 h before bacterial challenge was as effective as vancomycin in preventing experimental infection in tissue cages injected with either 10(2), 10(3), or 10(4) CFU of MRSA. In a rat model evaluating the therapy of chronic tissue cage infection caused by MRSA, the efficacy of a 7-day high-dose (30 mg/kg once daily) regimen of teicoplanin was compared with that of vancomycin (50 mg/kg twice daily). Whereas high levels of teicoplanin were found in tissue cage fluid, continuously exceeding its MBC for MRSA by 8- to 16-fold, no significant reduction in the viable counts of MRSA occurred during therapy. In contrast, either vancomycin alone or a combined regimen of high-dose teicoplanin plus rifampin (25 mg/kg twice daily) could significantly decrease the viable counts in tissue cage fluids. Whereas the bacteria recovered from tissue cage fluids during therapy showed no evidence of teicoplanin resistance, they failed to be killed even by high levels of this antimicrobial agent. The altered susceptibility of in vivo growing bacteria to teicoplanin killing might in part explain the defective activity of this antimicrobial agent when used as monotherapy against chronic S. aureus infections. These data may indicate the need for a combined regimen of teicoplanin with other agents such as rifampin to optimize the therapy of severe staphylococcal infections.

Performance of a fluorescence polarization immunoassay for teicoplanin in serum

Teicoplanin is a new glycopeptide antibiotic that is structurally related to vancomycin, but has six major components and is > 90% protein bound. We have developed a competitive homogeneous fluorescence polarization immunoassay (FPIA) for the quantitative determination of teicoplanin in serum. The teicoplanin FPIA uses six serum-based calibrators over the range 0-100 micrograms/ml, with the lowest teicoplanin concentration at 5 micrograms/ml and a lower limit of detection of < 1.5 micrograms/ml. Samples with concentrations > 100 micrograms/ml can be analyzed after 1:5 dilution with serum. Intra- and interassay precision are < 2% and < 4.5%, respectively, for controls at 7.5, 35, and 75 micrograms/ml on an automated FPIA analyzer. Recovery results for 30 samples prepared from the teicoplanin analytical reference standard over the range 3.4-358 micrograms/ml were linearly correlated with target concentrations; the linear regression equation and correlation coefficient are FPIA = 0.976 x target + 0.120, r = 0.999. Abnormal levels of bilirubin, hemoglobin, albumin, triglycerides, or cholesterol did not significantly affect recovery. Cross-reactivity with vancomycin was < 0.2%, and there was no significant interference from above therapeutic levels of likely concomitant medications. Results on patient samples from the teicoplanin FPIA were highly correlated with both a high-performance liquid chromatography (HPLC) method (FPIA = 1.032 x HPLC + 2.79, r = 0.979, n = 203) and the reference teicoplanin microbiologic assay method (orthogonal regression; FPIA = 1.111 x bioassay + 2.107, r = 0.969, n = 1014). A version of the teicoplanin FPIA for use with a modular clinical research FPIA analyzer showed comparable performance in all respects to the automated assay.

In vitro activity of teicoplanin compared with vancomycin against methicillin-resistant Staphylococcus aureus derived from cystic fibrosis sputum

We evaluated the in vitro activity of teicoplanin compared with vancomycin against methicillin-resistant Staphylococcus aureus (MRSA) derived from cystic fibrosis (CF) sputum. Teicoplanin had a slightly lower median minimum inhibitory concentration (MIC) for these strains (0.25 micrograms/ml) than did vancomycin (0.5 micrograms/ml). Inoculum size increased the MICs similarly for both drugs, and pH variations did not significantly affect their activity. The presence of serum and sputum in the growth media decreased the activity of both drugs, although this was more pronounced for teicoplanin which is highly protein bound. We conclude that teicoplanin has activity against this pathogen and might be evaluated in clinical protocols designed to address this emerging clinical problem.

An open study of teicoplanin in the treatment of gram-positive infections

Teicoplanin, a new glycopeptide antibiotic similar to vancomycin, was evaluated in treating 36 hospitalized patients suffering from various Gram-positive infections. The 36 patients received teicoplanin once daily as a mean intravenous injection of 550 mg/day (range 200-800 mg/day). Previous antimicrobial therapy was used in 28% of patients. The mean duration of therapy was 7.5 days (range 3-38 days). The overall clinical success rate was 94%. 24/36 patients (66%) had positive microbiology. Elimination of the pathogens was seen in 75% of all evaluable cases. Four patients with early prosthetic valve endocarditis due to coagulase negative Staphylococcus (3 patients) and Propionibacterium acnes (1 patient) had a favorable clinical and microbiological outcome. No adverse drug reactions were observed. Teicoplanin is safe and effective in the therapy of many different infections caused by Gram-positive bacteria.

Intravenous or intramuscular teicoplanin once daily for skin and soft-tissue infections

Teicoplanin is a new glycopeptide antibiotic with potent activity against gram-positive bacteria and pharmacokinetics that allow once daily administration. To study the efficacy and safety of teicoplanin for skin and soft-tissue infections, 75 patients received teicoplanin intravenously (38) or intramuscularly (37, of which 16 were outpatients). Of 62 clinically evaluable patients, 97 percent of teicoplanin iv and 93 percent of teicoplanin im patients were cured or improved. All teicoplanin iv patients and 64 percent of teicoplanin im patients were cured microbiologically at 24-48 hours posttherapy. Persistence of organisms frequently was associated with skin ulcers or abscess cavities and usually had no bearing on clinical outcome. Possible adverse clinical and laboratory reactions caused by teicoplanin occurred in 4 of 38 teicoplanin iv patients (11 percent) and in 8 of 37 teicoplanin im patients (22 percent). Reactions were mild and resolved with discontinuation of teicoplanin in most cases. In this study, teicoplanin appeared to be safe, efficacious, and convenient for both hospital staff and patients, and potentially cost-effective for the treatment of skin and soft-tissue infections. In particular, teicoplanin appears to be appropriate for outpatient parenteral therapy.

Clinical evaluation of teicoplanin fluorescence polarization immunoassay

A teicoplanin fluorescence polarization immunoassay (FPIA) developed by International BioClinical (IBC) was evaluated by using serum samples from patients who had been receiving teicoplanin at Detroit Receiving Hospital (DRH) as part of a clinical investigation. Patient samples collected over a 1-year span were assayed at DRH and at IBC, and the results were compared with those of a standard microbiological assay performed at Merrell Dow Research Institute, Indianapolis, Ind. The FPIA has a rapid turnaround time (circa 20 min), utilizes small sample volumes (less than 100 microliters) and is sensitive and accurate in determining concentrations in the range of 5 to 100 micrograms/ml. The intra-assay and interassay coefficient of variation for controls (7, 35, and 75 micrograms/ml) was less than or equal to 13%. Concentrations greater than 100 micrograms/ml must be diluted prior to the assay, which may introduce additional error in determination. The FPIA compared well with the bioassay (r = 0.901) for 193 clinical samples. The results obtained utilizing the FPIA system were reproducible at two different sites, as illustrated by the high degree of correlation between the results at DRH and IBC (r = 0.92). There was less than 7% interference noted when teicoplanin was assayed in the presence of other antibiotics. Patient samples stored for up to 1 year retained their potency: the mean recovery rate in these samples was 107%. The FPIA should be useful for monitoring and adjusting teicoplanin dosage regimens in patients.

Comparative effect of protein binding on the killing activities of teicoplanin and vancomycin

The effect of protein binding on the activity of teicoplanin against Staphylococcus aureus was evaluated. Bactericidal rates of teicoplanin in cation-supplemented Mueller-Hinton broth (SMHB) and in a 1:1 mixture of pooled human serum and cation-supplemented Mueller-Hinton broth (PHS-SMHB) were compared with those of vancomycin. Eight concentrations of each drug ranging from 15 to 150 micrograms/ml were studied in two series which correspond to the concentrations in serum achieved with low- (6 mg/kg of body weight once daily) and high-dose (30 mg/kg once daily) teicoplanin. Overall, the bactericidal rate of teicoplanin was lower than that of vancomycin. In the presence of serum, the bactericidal rate of teicoplanin in PHS-SMHB was lower than that in SMHB, often resulting in only one log10 drop in CFU over a 24-h period. There was no statistical difference in the bactericidal rates of high- and low-concentration teicoplanin in either medium. Additionally, concentration-dependent killing in SMHB was not evident with either agent. The bactericidal rates of teicoplanin and vancomycin in a 1:1 mixture of serum ultrafiltrate and SMHB at 60 micrograms/ml were also studied. It was noted that the bactericidal rate of neither agent was affected by the presence of serum ultrafiltrate. This finding is consistent with teicoplanin's high degree of protein binding (reported to be greater than 90% in undiluted serum) and further substantiates the hypothesis that only the free drug is active against microorganisms. These data support protein binding as being a factor in teicoplanin activity against S. aureus.

Teicoplanin pharmacokinetics in intravenous drug abusers being treated for bacterial endocarditis

The pharmacokinetics of teicoplanin were determined after multiple 30-min intravenous infusions of 10 to 15 mg/kg every 12 to 24 h in 11 intravenous drug abuse (IVDA) patients being treated for bacterial endocarditis. Multiple serum samples were obtained over 7 to 14 days. Twenty-four-hour urine collections were obtained on days 1 and 5. Serum concentration-time data were analyzed by using multiple-dose pharmacokinetic analysis (NONLIN84). Results were compared with pharmacokinetic parameters derived from previous studies in normal healthy volunteers following multiple intravenous infusions of teicoplanin (3 to 6 mg/kg/day). Total and renal clearances of teicoplanin in IVDA patients were found to be significantly greater and more highly variable than those observed previously in normal healthy volunteers. As a result, predicted steady-state trough concentrations in serum may vary up to fivefold. The mechanism responsible for this variation appears to be related to the glomerular filtration rate. In IVDA patients, individualized teicoplanin dosage may be required in the treatment of bacterial endocarditis.

Randomized study of vancomycin versus teicoplanin for the treatment of gram-positive bacterial infections in immunocompromised hosts

Seventy-four immunocompromised patients with severe infection due to gram-positive organisms were randomized to receive either vancomycin or teicoplanin. Extensive cancer was present in 71 patients, of whom 47 died within a month. The types of infections were 46 bacteremias (39 associated with central catheters), 24 skin and soft tissue infections (3 with bacteremia), and 7 others (mainly bronchopneumonia). The most frequent pathogen was Staphylococcus epidermidis, followed by Staphylococcus aureus. Microbiological eradication was obtained in 23 of 35 evaluable patients treated with vancomycin (65.7%) and 28 of 36 patients treated with teicoplanin (77.8%) (P = 0.4). Clinical cure and improvement were obtained in 26 of 35 patients (74.3%) and 27 of 36 patients (75.0%), respectively. No significant side effects were observed with teicoplanin, in contrast to reversible increases in serum creatinine (three patients) and skin rashes (four patients) with vancomycin. Superinfection was observed in five patients treated with vancomycin and two patients treated with teicoplanin. No relation was found between peak concentration in serum (at steady state) or bactericidal titers and outcome.

Treatment of infection and colonization caused by methicillin-resistant Staphylococcus aureus

The mechanism of methicillin resistance confers resistance to all available beta-lactam antibiotics; consequently, beta-lactam antibiotics have no role in therapy of methicillin-resistant Staphylococcus aureus (MRSA) infections. Vancomycin remains the drug of choice. Teicoplanin and daptomycin are two investigational antibiotics related to vancomycin in structure and in spectrum of activity. In clinical trials employing relatively low doses, neither was as effective as vancomycin. Trials at higher doses are on-going. Quinolones, ciprofloxacin in particular, have been used successfully to treat infections caused by MRSA; however, the usefulness of quinolones may be limited by the tendency of resistance to emerge during therapy. Quinolones probably should be used only in combination with another active agent, such as rifampin, when treating serious infections caused by MRSA. Other agents may be active in vitro against MRSA, but clinical data showing their effectiveness are lacking. Rifampin combination regimens appear most effectively to eradicate colonization with MRSA.

Ceftazidime plus teicoplanin versus ceftazidime plus amikacin as empiric therapy for fever in cancer patients with granulocytopenia

In a prospective randomized study, 100 episodes of fever (greater than 38 degrees C) and granulocytopenia (less than 1000/microliters) in cancer patients were empirically treated with ceftazidime (2 g every 8 h) plus teicoplanin (400 mg every 8 h on day 1; 400 mg every day thereafter) or ceftazidime (2 g every 8 h) plus amikacin (500 mg every 8 h). Bacteraemia, clinically documented infection and possible infection were documented in seven, 11 and 19 patients treated with ceftazidime plus teicoplanin and in 11, four and 17 patients treated with ceftazidime plus amikacin. Overall, the response rate was similar in the two groups of patients as was the need for treatment modifications and the rate of death. For documented Gram-positive bacteraemia, the response rate was 2/5 patients treated with ceftazidime plus teicoplanin and 2/7 with ceftazidime plus amikacin; for documented Gram-negative bacteraemia, the response rate was 1/2 and 3/4 patients respectively. No breakthrough bacteraemia was observed. Tolerance was excellent, although renal toxicity (elevation of serum creatinine) was observed in three patients treated with ceftazidime plus teicoplanin and in none allocated to ceftazidime plus amikacin.

Teicoplanin compared to flucloxacillin for antibiotic treatment of neutropenic patients

Ninety-eight neutropenic patients were randomized to receive piperacillin and gentamicin in combination with either teicoplanin or flucloxacillin. Sixty-seven of these patients, most of whom had myeloma, were given this combination as prophylaxis 5 d after high dose chemotherapy, 35 receiving flucloxacillin and 32 receiving teicoplanin. Of 31 patients with leukaemia who were febrile and neutropenic following induction chemotherapy or bone marrow transplantation, 18 received flucloxacillin and 13 received teicoplanin. For those given flucloxacillin, the mean number of days to change of antibiotics was 7.8 in the prophylaxis group and 5.1 in the treatment group. In the teicoplanin arm, the mean number of days to change antibiotics was 6.8 in the prophylaxis group and 6.1 in the treatment group. Two patients in the flucloxacillin arm developed drug rashes. Four patients developed rigors after teicoplanin administration and one asthmatic became wheezy. One patient had a progressive rise in creatinine, but overall the patients having teicoplanin did not have any appreciable increase of renal toxicity compared to the flucloxacillin arm. Blood cultures were positive prior to commencement in the treatment group in nine patients, and during treatment in six patients. Organisms grown were Gram-positive in 14 patients. Teicoplanin appears to be as effective as flucloxacillin when each is used in combination with piperacillin and gentamicin in the treatment of neutropenic patients, with similar rates of toxicity.

Teicoplanin. A review of its antibacterial activity, pharmacokinetic properties and therapeutic potential

Teicoplanin is a glycopeptide antibiotic with a molecular structure which is related to that of vancomycin. Gram-positive bacteria such as staphylococci (including methicillin-resistant strains), streptococci, enterococci and many anaerobic Gram-positive bacteria are susceptible to teicoplanin in vitro. Teicoplanin has an exceptionally long half-life, allowing once-daily intramuscular or intravenous administration. Teicoplanin is clinically and bacteriologically effective against a wide variety of Gram-positive infections such as septicaemia, endocarditis, skin and soft tissue infections and infections associated with venous catheters. The drug is equally efficacious against methicillin-resistant and -susceptible staphylococci. Adverse effects with teicoplanin are generally limited to local effects or hypersensitivity reactions. While teicoplanin has the potential for ototoxicity and nephrotoxicity, the incidence appears to be quite low when recommended serum concentrations are maintained. Teicoplanin is a valuable alternative to vancomycin, and providing controlled comparative studies prove equivalent safety and efficacy between the 2 glycopeptides the more easily administered teicoplanin should become the preferred antibacterial agent.

Application of a modified bioassay for monitoring serum teicoplanin and vancomycin in febrile neutropenic patients

Teicoplanin is a glycopeptide antibiotic with a mode of action and spectrum of activity similar to those of vancomycin. Its efficacy and tolerability as empiric therapy and its pharmacokinetic properties in neutropenic patients are being studied in a double-blinded, randomized trial in comparison with those of vancomycin. We report here a modified agar diffusion bioassay which is suitable for monitoring levels of either teicoplanin or vancomycin in serum during combination therapy with beta-lactams, aminoglycosides, and amphotericin B. Serum samples spiked with either teicoplanin or vancomycin gave reproducible results (mean coefficient of variation, 8.8%) regardless of the presence of tobramycin, amikacin, piperacillin, ceftazidime, amphotericin B, or their combinations. Among 25 patients who received teicoplanin at a dosing schedule of 6 mg/kg every 24 h intravenously, steady state was reached after 14.2 +/- 4.0 days, and 1-h peak and trough concentrations of teicoplanin in serum at steady state were 40.8 +/- 15.0 and 12.5 +/- 3.2 mg/liter, respectively. In contrast, among 25 patients who received vancomycin at a dosing schedule of 15 mg/kg every 12 h intravenously, steady state was reached by 24 h, and the 1-h peak and trough concentrations in serum were 37.5 +/- 15.6 and 8.3 +/- 3.8 mg/liter, respectively. The elimination half-lives for teicoplanin estimated by two separate approaches agreed closely with each other: 80.5 +/- 21.5 h by an accumulation model (M. Gilbaldi and D. Perrier, Pharmacokinetics, 2nd ed., p. 121, 1982) and 87.3 +/- 19.3 h as predicted from the degree of renal function (M. Rowland, Clin. Pharmacokinetic 18:184-209, 1990). These values were 14- to 15-fold higher than that for vancomycin (5.6 +/- 1.8 h). Since considerable variability was noted in the pharmacokinetic parameters for both teicoplanin and vancomycin among the individual patients, our data further emphasized the need for frequent monitoring of these drugs during empiric therapy of the febrile neutropenic patient.

Cefotaxime and prophylaxis. New approaches with a proven agent

Cefotaxime, a third-generation cephalosporin, is active against many troublesome gram-negative organisms and anaerobes that now more frequently cause nosocomial infection. Single-dose cefotaxime, 1 g or 2 g administered 30 minutes prior to surgery, has been proven to be effective as prophylaxis for infection following gastrointestinal, biliary, obstetric, gynecologic, and genito-urinary procedures. When published trials are compiled, single-dose cefotaxime is more effective than multiple-dose cefazolin (p less than 0.01) in these types of surgery. Unfortunately, the dramatic increase in cephalosporin use has been accompanied by the emergence of resistant organisms such as enterococci and fungi. In Europe, some centers successfully prevent nosocomial pneumonia in intubated patients by decontaminating gastric contents with a combination of nonabsorbable antimicrobial agents including cefotaxime. Further trials may validate this concept for use in the United States.

Effects of dosage, peak and trough concentrations in serum, protein binding, and bactericidal rate on efficacy of teicoplanin in a rabbit model of endocarditis

The effect of dosage and the relative importance of peak and trough concentrations in serum for efficacy of teicoplanin were examined in a rabbit model of aortic valve endocarditis. Concentrations of teicoplanin in serum exceeded the MIC by several hundredfold, yet teicoplanin was less rapidly bactericidal than penicillin both in vitro and for endocarditis caused by a strain of Streptococcus sanguis. Because teicoplanin was 90% protein bound in rabbit serum, low free-drug concentrations probably resulted in less activity in vivo than in vitro. Because teicoplanin has a relatively low bactericidal rate and a high degree of protein binding, a sustained concentration in serum several times greater than the MIC may be important for efficacy in vivo. An intravenous regimen with relatively high peak concentrations in serum was less effective than an intramuscular regimen for endocarditis caused by a strain of Staphylococcus aureus, indicating that high peaks are unlikely to be an important determinant of efficacy. The therapeutically more relevant concentration in serum may be the trough.

Clinical pharmacokinetics of teicoplanin

Teicoplanin is a recently introduced glycopeptide antibiotic for the treatment of a variety of aerobic and anaerobic Gram-positive infections. It is a mixture of 5 closely related components, of similar polarity and biological activity, and 1 or more polar hydrolysis products. Teicoplanin is rapidly and extensively absorbed from muscle and the peritoneal cavity but very poorly absorbed from the gastrointestinal tract. Following intravenous administration, the disposition kinetics are best described by a tri-exponential equation, and the majority of drug is excreted unchanged, by glomerular filtration. In patients with normal renal function, the half-lives of the first, second and terminal phases are 35 minutes, 10 hours and 87 hours, respectively. The initial volume of distribution is 0.089 L/kg, the volume of distribution at steady-state is 0.86 L/kg, clearance is 0.0114 L/h/kg and renal clearance is 0.0083 L/h/kg. Teicoplanin is highly bound in plasma to albumin (fraction unbound = 0.1) and in tissues. The pharmacokinetics are linear over a wide dose range (2 to 26 mg/kg). The minor differences in the pharmacokinetics of the components of teicoplanin can be accounted for by differences in lipophilicity. The events following multiple dosing are predicted from single dose data; renal clearance decreases in patients with renal insufficiency in a predictable manner. Negligible drug is lost during haemodialysis. As expected, clearance per kilogram is higher in children than in adults, and lower in the elderly, associated with a decrease in glomerular filtration rate with advancing years. Tissue distribution data are limited. Concentrations, relative to those in plasma, are high in lung and bone tissue and low in fat. Animal data show high concentrations in most tissues, and particularly high in liver and kidneys. Teicoplanin penetrates slowly and poorly into cerebrospinal fluid, but relatively rapidly and effectively in synovial and pleural fluids and in soft tissue. The manufacturer's recommended intravenous or intramuscular dosage regimens rapidly achieve and maintain adequate plasma concentrations of teicoplanin; the dosing interval is usually 1 day. The maintenance dosing rate, but not the loading dose (if needed), must be reduced in patients with poor renal function and in the elderly. For those patients on continuous ambulatory peritoneal dialysis, the peritoneal cavity offers a convenient alternative route of drug administration.

The prevalence of staphylococcal resistance to penicillinase-resistant penicillins. A retrospective and prospective national surveillance trial of isolates from 40 medical centers

In a retrospective survey of resistance to penicillinase-resistant penicillins (PRPs) in 152,076 clinical staphylococcal strains isolated in 40 United States Hospitals in 1985 and 1986, rates of resistance to oxacillin were found to be 11 and 13%, respectively, among Staphylococcus aureus isolates. The rates were approximately four times higher among coagulase-negative staphylococcal strains. In a prospective study of 1,408 wound or bacteremia isolates from the participant hospitals, oxacillin and methicillin agar screening, disk diffusion, and broth microdilution testing were conducted at a single reference laboratory. These tests yielded PRP resistance rates of 15% among S. aureus, 75% among S. epidermidis, and 48% among other coagulase-negative strains. No major changes in the distribution of resistance rates among hospitals or by hospital type were observed. Dilution susceptibility testing of several antimicrobial agents against PRP-resistant isolates and species-matched susceptible isolates from the same hospital showed that teicoplanin and vancomycin were the most active drugs (100% of S. aureus isolates were susceptible). Teicoplanin and vancomycin disk diffusion testing of all PRP-resistant staphylococcal strains also showed that these isolates were susceptible to the glycopeptides. However, agar dilution screening and broth microdilution tests revealed that several coagulase-negative strains, predominantly S. haemolyticus, had teicoplanin MICs greater than or equal to 8 micrograms/ml. S. haemolyticus isolates represented a very small number of the total stains tested. Teicoplanin and vancomycin were also the most active drugs when tested against older (1962-82) clinical PRP-resistant S. aureus strains from the reference laboratory collection. The methods found to be superior in detecting PRP-resistant strains were the oxacillin 6 micrograms/ml agar screening test in 4% NaCl-supplemented Mueller-Hinton agar and the 1 microgram oxacillin disk test. By reference laboratory standards, participant laboratories were incorrect in only 2.3% of species identifications and 4.5% of oxacillin-susceptibility determinations, indicating acceptable contemporary agreement and accuracy.

Evaluation of teicoplanin for treatment of endocarditis caused by gram-positive cocci in 20 patients

Teicoplanin, a new glycopeptide antibiotic similar to vancomycin, was evaluated for the treatment of bacterial endocarditis in an open multicenter study from May 1985 to August 1987. A total of 20 patients with positive blood culture endocarditis received teicoplanin once daily as a mean intravenous injection of 7.3 mg/kg of body weight (range, 4.8 to 10.6 mg/kg); in 17 patients, teicoplanin was combined with another antibiotic, usually an aminoglycoside. The mean duration of therapy was 28 days (range, 7 to 66 days). The diagnosis of endocarditis was confirmed by echocardiography or anatomical findings in 15 patients and established on the basis of clinical manifestations plus positive blood cultures in 5 patients. The tricuspid valve was involved in 11 of the 20 patients. Isolates from blood were 12 Staphylococcus aureus, 1 Staphylococcus hominis, 1 Micrococcus sedentarius, 1 Enterococcus faecalis, 3 Streptococcus bovis, and 2 nongroupable Streptococcus sp. At the end of therapy, bacterial eradication was achieved in 17 of 20 patients (85%), and a favorable clinical outcome had occurred in 14 of 17 evaluable patients (82%). Of these 14 patients, one relapsed 4 months after the end of treatment. Thus, teicoplanin was effective in 13 of 17 patients (76%). Mean peak levels of teicoplanin in serum were lower, 23.1 +/- 2.9 micrograms/ml, in patients who failed than in those who were cured (45.8 +/- 8.4 micrograms/ml). Side effects occurred in 7 of 20 patients (35%), and required premature discontinuation of teicoplanin in 3 patients. These side effects were fever in three patients, rash in three patients, hearing loss in two patients, and increased serum transaminase levels in two patients. This study demonstrates the efficacy of teicoplanin in the treatment of endocarditis and the need for achieving peak levels in serum close to 40 micrograms/ml. Teicoplanin should now be further evaluated in endocarditis caused by gram-positive cocci means of controlled comparative study with standard therapy.

Leukopenia with neutropenia associated with teicoplanin therapy

The first case report of leukopenia with neutropenia due to the new glycopeptide antibiotic teicoplanin is described. The side effect occurred in a 73-year-old man hospitalized because of subacute bacterial endocarditis caused by Streptococcus faecalis. Leukopenia with neutropenia (white blood cells 2000/mm3, neutrophils 46%) developed after 20 days of teicoplanin therapy. After stopping teicoplanin white blood cell and neutrophil counts reverted to normal, but dropped again on rechallenge. A review of 1500 records of patients treated with teicoplanin alone or in combination with other drugs was also performed. Five cases were found in which leukopenia was possibly (four cases) or probably (one case) related to teicoplanin therapy. From these preliminary data the incidence of leukopenia related to teicoplanin seems to be low.

Therapeutic update on glycopeptide and lipopeptide antibiotics

Glycopeptide antibiotics in the form of vancomycin have been available for almost 30 years. In the past, vancomycin usually was reserved as an alternative agent to treat staphylococcal and streptococcal infection in patients with a penicillin allergy or hemodialysis shunt infection. With the increasing frequency of both methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis, now it is often used as a first-line agent. Over a 10-year period, vancomycin sales have increased by almost $1 hundred million. Several new glycopeptide and lipopeptide antibiotics are in various stages of evaluation. While vancomycin resistance to date is a rare phenomenon, these drugs represent a potentially more potent and safer antibiotic alternative to vancomycin. Teicoplanin and daptomycin are two of these investigational agents.

Methicillin-resistant staphylococci

Strains of staphylococci resistant to methicillin were identified immediately after introduction of this drug. Methicillin-resistant strains have unusual properties, the most notable of which is extreme variability in expression of the resistance trait. The conditions associated with this heterogeneous expression of resistance are described. Methicillin resistance is associated with production of a unique penicillin-binding protein (PBP), 2a, which is bound and inactivated only at high concentrations of beta-lactam antibiotics. PBP2a appears to be encoded by the mec determinant, which also is unique to methicillin-resistant strains. The relationships between PBP2a and expression of resistance and implications for the mechanism of resistance are discussed. The heterogeneous expression of methicillin resistance by staphylococci poses problems in the detection of resistant strains. Experience with several susceptibility test methods is reviewed and guidelines for performance of these tests are given. Treatment of infections caused by methicillin-resistant staphylococci is discussed. Vancomycin is the treatment of choice. Alternatives have been few because methicillin-resistant strains often are resistant to multiple antibiotics in addition to beta-lactam antibiotics. New agents which are active against methicillin-resistant staphylococci are becoming available, and their potential role in treatment is discussed.

Teicoplanin: a new glycopeptide antibiotic complex

The chemistry, microbiology, pharmacokinetics, clinical efficacy, and adverse effect profile of teicoplanin are reviewed and, where appropriate, compared with vancomycin. Teicoplanin is a glycopeptide antibiotic with potent bactericidal activity against a wide variety of aerobic and anaerobic gram-positive bacteria. In contrast to the structurally related vancomycin, teicoplanin has a prolonged elimination half-life of approximately 60 hours and it may be safely administered by the intramuscular route. Adverse effects of teicoplanin include ototoxicity, nephrotoxicity, skin rash, eosinophilia, neutropenia, and transient elevation of serum aminotransferases. Teicoplanin may be beneficial as an alternative to vancomycin for patients with poor vascular access and in those requiring long-term outpatient therapy. The role of teicoplanin in the treatment and prophylaxis of gram-positive infections will ultimately depend on its unfolding safety and efficacy profile.

Pharmacokinetics of teicoplanin in critically ill patients with various degrees of renal impairment

The pharmacokinetics of teicoplanin were studied in 15 adult patients in the acute phase of severe infections caused by gram-positive cocci. All the subjects were given a daily intravenous bolus dose of 6 mg of teicoplanin kg-1 (body weight). The pharmacokinetic study was performed over a 48-h period after injection 4. The subjects were categorized according to their mean creatinine clearances (ml.min-1.kg-1) during the study period: group 1 (n = 3), greater than 1.6; group 2 (n = 6), 0.8 to 1.6; and group 3 (n = 6), 0.15 to 0.8. Mean concentrations of teicoplanin in serum at 1, 24, and 48 h were 33 +/- 8, 9 +/- 3, and 6 +/- 2.5 micrograms.ml-1, respectively. The mean half-lives of the concentration-time curve from 12 to 48 h were 28 +/- 4, 44 +/- 24, and 48 +/- 14 h in groups 1, 2, and 3, respectively (group 3 versus group 1: P less than 0.05). The mean area under the serum concentration-time curve from time zero to 24 h was 344 +/- 92 mg.h.liter-1, and the mean hybrid volume of distribution was 1.09 +/- 0.46 liter.kg-1. These values were similar for the three groups, with a trend for larger areas under the curve in group 3. Creatinine clearance correlated directly with the total body clearance of teicoplanin (r = 0.70) and with the renal clearance of teicoplanin (r = 0.82). However, in critically ill patients, the wide interindividual variations in pharmacokinetic parameters are more relevant than those related to the variations in renal function when creatinine clearance is above 0.30 ml.min-1.kg-1. We concluded that, in such conditions, monitoring of concentrations of teicoplanin in serum is mandatory.