Optimising Vancomycin Treatment for Coronavirus with the Help of Chromatography

Covid-19 disease caused by coronavirus has been a major news topic since it was first reported in December 2019. It was first reported in Wuhan, China by doctors who spotted a small cluster of pneumonia cases. The search for a cure and a vaccine is one of the main areas of health research currently being undertaken. There are several secondary complications due to Covid-19 including neurological symptoms such as cognitive impairment, pulmonary symptoms including coughing and chest tightness and lung damage.

Another complication are the bacterial infections that have been seen in over 30% of Covid-19 patients who required mechanical ventilation and in over 50% of deaths that have been attributed to Covid-19. These infections are treated by courses of antibiotics. Unfortunately, sometimes you cannot just throw antibiotics at the problem. Treatment must be administered at what is known as the therapeutic dose – just the right amount of antibiotic to attack the infection. Too little and the infection is too strong, too much and the side effects of the drug can be just as deadly as the disease.

Secondary infections with Covid-19

Secondary bacterial infections associated with Covid-19 have been caused by gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase-negative Staphylococci (MRCNS) and Enterococci species. These common nosocomial infections can cause ventilator-associated pneumonia are commonly treated with an antibiotic known as vancomycin. However, it has a narrow treatment window and some patients react differently to the drug leading to sub-optimal vancomycin concentrations in patients.

To monitor this, therapeutic drug monitoring of vancomycin must be carried out to ensure that the drug treatment is clinically effective whilst avoiding adverse reactions including acute kidney injury. Therapeutic drug monitoring (TDM) is the practice of measuring a drug at designated intervals to maintain a constant concentration in a patient's bloodstream, this can help to optimizing the dose a patient gets. For most drugs, TDM is unnecessary, it is mainly used for those that have narrow therapeutic range or those that might cause adverse effects.

TDM to find the dose

The correct dose is based on various factors including a patient’s age, weight, and organ function and TDM can form the basis of a feedback loop whereby the drug’s dose is constantly changed. A report from Fudan University in China describes how this was carried out on vancomycin concentrations being used on patients admitted with Covid-19. The team used liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) to monitor the vancomycin concentration in patient’s serum samples and the results were used to alter the dosage of vancomycin administered to the patients. The use of liquid chromatography with tandem mass spectrometry is the subject of the article, Separation of the 4 Enantiomers of the Fungicide Spiroxamine by LC-MS/MS.