Vancomycin is not as good a choice as beta-lactams in the fight against strains sensitive to methicillin S. aureus in clean surgery departments
Prescribing antibiotics to all patients operated on to prevent infections caused by methicillin-sensitive strains of S. aureus, in practice, is impractical.
Following a study by Australian scientists, vancomycin has been found to be an effective drug for the control of methicillin-resistant strains of S. aureus (MRSA), and its use is associated with an increase in the number of infections caused by isolates susceptible to methicillin S. aureus (MSSA).
According to the researchers, if there are sufficient reasons to prescribe vancomycin for prevention purposes, it is better to use anti-staphylococcal β-lactam antibiotics.
In most cases, surgical infections caused by MSSA are more common than MRSA infections, even if MRSA is endemic in the hospital, so scientists want to make every effort to prevent the development of these infections.
A prospective study collected data on more than 22,500 own heart, knee and hip surgeries, performed from 2002 to mid-2009 in Melbourne clinics. Vancomycin was prescribed prophylactically to 1,610 patients; 20,939 patients received only β-lactam antibiotics.
The differences between the two groups are that the majority of patients who received vancomycin underwent hip surgery, which last longer and are at higher risk according to the American Society of Anesthesiologists (ASA), as well as among patients in this group, there were fewer people who received antibiotics for acceptable periods (p less than 0.001 for all differences).
Overall, 754 patients (3.3%) developed surgical infections. This indicator was significantly higher in the vancomycin group compared to β-lactams (5.3% vs 3.2%, p less than 0.001). The most common infectious agents were MSSA (180 cases), MRSA (136 cases) and microorganisms of the genus Pseudomonas (68 cases).
According to the results of the multivariate analysis, the risk factors associated with the development of any infection were the duration of the operation (RR 1.003, p less than 0.001), a score on the ASA scale greater than 3 (RR 1.713, p less than 0.001) and the appointment of vancomycin for prevention (RR 1.404, p = 0.04).
Vancomycin was also associated with a significant increase in the risk of developing an MSSA infection (RR 2,793, p less than 0.001).
One of the drawbacks of the study was incomplete information on the timing of administration of vancomycin. It was also noted that during the study, no data were collected on vancomycin dosage regimens, while in some centers it was decided to use a higher loading dose of the drug. The authors suggest that in many hospitals during the study, an initial dose of 1 g of vancomycin was prescribed to patients for both prophylaxis and treatment. With this approach, the optimal therapeutic / balance drug concentration was often not reached within a few days.
Scientists are concerned that surgeons' desire to reduce the risk of developing infections in their patients often leads to the appointment of antibiotics with a broader spectrum of action or a longer course than necessary. Given the high risk of developing pseudomembranous colitis under these conditions, some researchers recommend the inclusion of vancomycin in antibiotic treatment regimens.
The joint leadership of the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, the American Society for Healthcare Epidemiology of America and the Society of Surgical (Surgical Infection Society), who will recommend the use combination of vancomycin and β-lactam antibiotics for the prevention of surgical infections.