Part A:
Treatment, Dose, Log of number of colonies, Mean.
Control -- 9.0, 9.5, 9.0, 8.9 9.1
Vancomycin 1.0 8.5, 8.4, 8.2 8.4
5.0 5.3, 5.9, 4.7 5.3
Teixobactin 1.0 8.5, 6.0, 8.4, 6.0 7.2
5.0 3.8, 4.9, 5.2, 4.9 4.7
which of the following statements most appropriately reflects the relative effectiveness of the vancomycin treatment, teixobactin treatment, and the control?
a) Teixobactin was significantly less effective than the vancomycin at reducing the number of MRSA colonies relative to the control.
b) Neither teixobactin or vancomycin were effective at reducing the number of MRSA colonies relative to the control.
c)Teixobactin was significantly more effective than the vancomycin at reducing the number of MRSA colonies relative to the control.
d) Teixobactin reduced the number of MRSA colonies about as effectively as did vancomycin relative to the control
Answer: A. Teixobactin was significantly less effective than the vancomycin at reducing the number of MRSA colonies relative to the control.
Explanation: By way of definition, Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of health care-associated infections. Vancomycin remains an acceptable treatment option. Though there is an evolution of microbial resistance to vancomycin which posed to be a problem, in particular, within healthcare facilities such as hospitals. While newer alternatives to vancomycin exist, the widespread use of vancomycin makes resistance to the drug a significant worry, especially for individual patients if resistant infections are not quickly identified and the patient continues the ineffective treatment. There has been a welcome increase in the number of agents available for the treatment of MRSA infection for instance the Teixobactin, Linezolid, daptomycin, telavancin and ceftaroline. These drugs have certain differentiating attributes and may offer some advantages over vancomycin, but they also have significant limitations.
Teixobactin was also found to be effective in vivo, when used to treat mice infected with methicillin-resistant S. aureus (MRSA), and Streptococcus pneumoniae. The dose required to achieve 50% survival against MRSA is only 10% of the PD50 dose of vancomycin, an antibiotic typically used for MRSA. However, Teixobactin was reported to be potent in vitro against all gram-positive bacteria tested, including Staphylococcus aureus and difficult-to-treat enterococci, with Clostridium difficile and Bacillus anthracis being exceptionally vulnerable. It also killed Mycobacterium tuberculosis.
Teixobactin is not active against bacteria with an outer membrane such as gram negative pathogens, particularly carbapenem resistant enterobacteriaceae. It is possible from the results, that genes encoding resistance to teixobactin are already present in soil bacteria. Resistance could also arise by mutation after prolonged use of teixobactin in patients. So based on the experiment conducted, Teixobactin was significantly less effective than the vancomycin at reducing the number of MRSA colonies relative to the control.
