A risk-benefit assessment of teicoplanin in the treatment of infections

Targeting host cell proteases as a potential treatment strategy to limit the spread of SARS-CoV-2 in the respiratory tract

As the death toll of Coronavirus disease 19 (COVID-19) continues to rise worldwide, it is imperative to explore novel molecular mechanisms for targeting SARS-CoV-2. Rather than looking for drugs that directly interact with key viral proteins inhibiting its replication, an alternative and possibly add-on approach is to dismantle the host cell machinery that enables the virus to infect the host cell and spread from one cell to another. Excellent examples of such machinery are host cell proteases whose role in viral pathogenesis has been demonstrated in numerous coronaviruses. In this review, we propose two therapeutic modalities to tackle SARS-CoV-2 infections; the first is to transcriptionally modulate the expression of cellular proteases and their endogenous inhibitors and the second is to directly inhibit their enzymatic activity. We present a nonexhaustive collection of clinically investigated drugs that act by one of these mechanisms and thus represent promising candidates for preclinical in vitro testing and hopefully clinical testing in COVID-19 patients.

Total Syntheses of Vancomycin-Related Glycopeptide Antibiotics and Key Analogues

A review of efforts that have provided total syntheses of vancomycin and related glycopeptide antibiotics, their agylcons, and key analogues is provided. It is a tribute to developments in organic chemistry and the field of organic synthesis that not only can molecules of this complexity be prepared today by total synthesis but such efforts can be extended to the preparation of previously inaccessible key analogues that contain deep-seated structural changes. With the increasing prevalence of acquired bacterial resistance to existing classes of antibiotics and with the emergence of vancomycin-resistant pathogens (VRSA and VRE), the studies pave the way for the examination of synthetic analogues rationally designed to not only overcome vancomycin resistance but provide the foundation for the development of even more powerful and durable antibiotics.

Glycopeptide-Induced Neutropenia: Cross-Reactivity Between Vancomycin and Teicoplanin

Objective:

To report teicoplanin-related neutropenia that developed after an episode of neutropenia induced by vancomycin therapy.

Case Summary:

A 57-year-old female suffered from osteomyelitis of the left humerus, with a white blood cell (WBC) count of 2.8 × 103/mm3 and absolute neutrophil count (ANC) of 0.28 × 103/mm3, occurring after 24 days of vancomycin therapy. Vancomycin was changed to teicoplanin and the agranulocytosis resolved 4 days later. However, a new episode of neutropenia, with a WBC count of 2.8 × 103/mm3 and ANC of 0.448 × 103/mm3, occurred 11 days after teicoplanin initiation. Agranulocytosis resolved 4 days following withdrawal of teicoplanin.

Discussion:

Because of the close time relationship between drug administration and the development of symptoms and signs, as well as between drug withdrawal and changes in WBC count and ANC, the episodes of neutropenia were suspected to be drug related. Teicoplanin-induced agranulocytosis that followed vancomycin-induced agranulocytosis suggests a possible cross-reactivity between the 2 drugs. Both reactions were categorized as probable according to the Naranjo probability scale.

Conclusions:

For all patients with vancomycin-induced neutropenia, possible cross-reactivity of teicoplanin should be monitored.

A Case of Teicoplanin-Induced Pancytopenia Caused by Excessive Dosing

Teicoplanin is reported to be as effective as vancomycin but with minimal side effects. We report a case of teicoplanin-induced pancytopenia, which has not been demonstrated previously. A 44-year-old man with tetraplegia was treated with a diagnosis of urinary tract infection and pneumonia, and a high-dose of teicoplanin (400 mg every 12 hours) was administered for 4 days inadvertently. Although the infection rapidly improved, the patient developed pancytopenia by the fourth day of teicoplanin therapy, which was improved after reducing the dose of teicoplanin (200 mg/d). Our patient represents a probable case of teicoplanin-induced pancytopenia with adverse drug reaction probability score of 6.

Significance of individual adjustment of initial loading dosage of teicoplanin based on population pharmacokinetics

An initial loading dose of teicoplanin is required to reach the optimal trough concentration (> or = 10 microg/mL) rapidly. To attain the optimal teicoplanin concentration efficiently, an individual loading dose regimen based on population pharmacokinetics, in which the target trough concentration was set to 15 microg/mL, was defined. Among 70 patients, 33 patients received the individual loading dose regimen, 33 patients received the conventional loading dose regimen (200mg or 400mg every 12h on Day 1 followed by 200mg once daily) and 4 patients received no loading dose. The proportion of patients showing an optimal plasma concentration was 88% in the individual loading dose regimen but only 33% in the conventional loading dose regimen. No patient without a loading dose showed the optimal concentration. Both total loading dose and plasma concentration were significantly (P<0.001) higher in the individual loading dose group than in the conventional loading dose group. Notably, the trough concentration was almost constant in patients with individual loading doses ranging from 800 mg to 1800 mg. These findings suggest that individual adjustment of the initial loading dose of teicoplanin is potentially useful to attain the optimal concentration rapidly.

Pharmacokinetics and efficacy of teicoplanin against intramammary infections in sheep

The pharmacokinetics of teicoplanin were evaluated in 10 healthy sheep. After intravenous injection it showed monophasic behaviour, with a short mean (sd) elimination half-life (5 [0.24] hours). After intramuscular injection its bioavailability was 100 per cent but it was absorbed slowly; its elimination half-life was satisfactorily slow (9.23 [0.74] hours). Its efficacy was evaluated in 26 crossbreed sheep with milk positive to strains of Staphylococcus aureus, coagulase-negative staphylococci and Streptococcus agalactiae, and clinical signs of disease. In 19 of them a single intramuscular dose of 6 mg/kg bodyweight resulted in a complete resolution of the clinical signs, and no microorganisms were detected in milk by the fifth day; in the other seven sheep, with more severe intramammary infections, three consecutive daily intramuscular doses of 6 mg/kg bodyweight were necessary. There were no local or systemic side effects and no relapses during 30 days after the treatments in any of the sheep.

Diagnosis and treatment of catheter-related infections in paediatric oncology: an update

Otherwise unexplained clinical signs of infection in patients with long-term tunnelled or totally implanted central venous access devices (CVADs) are suspected to be CVAD-associated. Diagnostic methods include catheter swabs, blood cultures and cultures of the catheter tip or port reservoir. In the case of a suspected CVAD-related bloodstream infection in paediatric oncology patients, in-situ treatment without prompt removal of the device can be attempted. Removal of the CVAD should be considered if bacteraemia persists or relapses > or = 72 h after the initiation of (in-vitro effective) antibacterial therapy administered through the line. Timely removal of the device is also recommended if the patient suffers from a complicated infection, or if Staphylococcus aureus, Pseudomonas aeruginosa, multiresistant Acinetobacter baumannii or Candida spp. are isolated from blood cultures. Duration of therapy depends on the immunological recovery of the patient, the pathogen isolated and the presence of related complications, such as thrombosis, pneumonia, endocarditis and osteomyelitis. Antibiotic lock techniques in addition to systemic treatment are beneficial for Gram-positive infections. Although prospectively controlled studies are lacking, the concomitant use of urokinase locks and taurolidine secondary prophylaxis seem to favour catheter salvage.

Synthesis and evaluation of methyl ether derivatives of the vancomycin, teicoplanin, and ristocetin aglycon methyl esters

A series of methyl ether derivatives of the vancomycin, teicoplanin, and ristocetin aglycon methyl esters was synthesized and their antimicrobial activity was established. These derivatives exhibit increased activity against VanB resistant strains of bacteria equipotent with that observed with sensitive bacteria.

Three-times weekly teicoplanin in the outpatient treatment of acute methicillin-resistant staphylococcal osteomyelitis: a pilot study

Treatment of osteomyelitis requires prolonged hospital stay, lengthy antibiotic therapy and adequate surgical debridement. Outpatient parenteral antibiotic therapy (OPAT) is a new approach to reduce patient discomfort and hospital costs. Teicoplanin, a glycopeptide antibiotic with a long half-life (72 hours), is one of the most useful drugs for OPAT. We performed a pilot study to assess the safety and efficacy of three-times weekly teicoplanin in the treatment of methicillin-resistant (MR) acute staphylococcal osteomyelitis. Ten patients with acute post-traumatic osteomyelitis were enrolled. Pathogens were MR Staphylococcus aureus (5 patients) and MR coagulase-negative staphylococci (5 patients). After a loading dose of 400 mg b.i.d. for 3 days, patients were treated with an intravenous dose of 1000 mg on Mondays and Wednesdays and with a 1200 mg dose on Fridays. Teicoplanin trough levels were maintained within a 10 to 20 mg/L range. If hardware removal had been possible at enrollment, treatment was carried out for at least 4 weeks. If, on the contrary, hardware removal had not been possible, teicoplanin was administered as suppressive therapy until hardware removal. Treatment was successfully performed in 9 out of 10 patients, whereas in one patient only improvement was achieved. Side effects were not recorded. Three times weekly teicoplanin seems to be a valuable option in the treatment of acute MR staphylococcal osteomyelitis. Further studies are warranted in order to better define the role of this new administration schedule in this field.

First and second generation total synthesis of the teicoplanin aglycon

Full details of studies leading to the total synthesis of the teicoplanin aglycon are provided. Key elements of the first generation approach (26 steps from constituent amino acids, 1% overall) include the coupling of an EFG tripeptide precursor to the common vancomycin/teicoplanin ABCD ring system and sequential DE macrocyclization of the 16-membered ring with formation of the diaryl ether via a phenoxide nucleophilic aromatic substitution of an o-fluoronitroaromatic (80%, 3:1 atropisomer diastereoselection) followed by 14-membered FG ring closure by macrolactamization (66%). Subsequent studies have provided a second generation total synthesis which is shorter, more convergent, and highly diastereoselective (22 steps, 2% overall). This was accomplished by altering the order of ring closures such that FG macrolactamization (95%) preceded coupling of the EFG tripeptide to the ABCD ring system and subsequent DE ring closure. Notably, DE macrocyclization via diaryl ether formation on substrate 57, the key intermediate in the latter approach incorporating the intact FG ring system, occurred with exceptional diastereoselection for formation of the natural atropisomer (>10:1, 76%) without problematic C(2)(3) epimerization provided the basicity of the reaction is minimized.

In-vitro and in-vivo antibacterial activity of BI 397, a new semi-synthetic glycopeptide antibiotic

BI 397 (formerly A-A-1) is a semisynthetic derivative of the teicoplanin-like glycopeptide A40926. It was more active in vitro against staphylococci (including some teicoplanin-resistant strains) than teicoplanin and vancomycin. Against streptococci (including penicillin-resistant strains) BI 397 has activity comparable with that of teicoplanin and better than vancomycin. BI 397, when administered to rats by the i.v. route, gives high and long lasting blood levels. It shows excellent activity in models of acute septicaemia in immunocompetent and neutropenic mice. In a rat staphylococcal endocarditis model it is as effective as teicoplanin and vancomycin at reducing bacterial loads in the heart, but at lower dosages and with a reduced number of daily treatments compared with the two glycopeptide controls. BI 397 is highly efficacious in clearing penicillin-susceptible and -resistant pneumococci from lungs of immunocompetent and neutropenic rats. The data from these studies show that BI 397 combines an excellent in-vitro antibacterial activity with favourable pharmacokinetic behaviour resulting in potent in-vivo activity.