Bi-121 Microbiology: Spectrum And Mode Assessment Answer

Antibiotic

Chemical class or

Classification

Spectrum of activity (gram +, -, or broad)

Mechanism of Action

Ciprofloxacin

Therapeutic: anti-infectives

Pharmacologic: Flurorquilones

Gram positive and gram negative

Inhibits bacterial DNA synthesis via inhibiting bacterial DNA gyrase (topoisomerase ii). DNA gyrase helps in the uncoiling of the bacterial DNA double helix during replication.

Aldred, K. J., Kerns, R. J., & Osheroff, N. (2014). Mechanism of quinolone action and resistance. Biochemistry, vol. 53(10), pp. 1565-1574. 10.1021/bi5000564

Colistin

Lipopolypeptide antibiotic

Gram negative

Interacts with the anionic lipopolysaccharide layers of the outer membrane of gram negative bacteria and increasest he cell permeability which promotes cell death.

Liu, Y. Y., Wang, Y., Walsh, T. R., Yi, L. X., Zhang, R., Spencer, J., ... & Yu, L. F. (2016). Emergence of plasmid-mediated colistin resistance mechanism MCR-1 in animals and human beings in China: a microbiological and molecular biological study. The Lancet infectious diseases, vol. 16(2), pp. 161-168. https://doi.org/10.1016/S1473-3099(15)00424-7

Moxalactam

oxa-beta-lactam antibiotic

Broad spectrum activity against gram positive and gram negative aerobic and anaerobic bacteria

It is a cephalosporin group of bacteria. It interferes the bactericidal activity via inhibiting the bacterial cell wall biosynthesis. It tampers the cross-linking of the peptidoglycan layer. It also activates autolysins causing bacterial cell lysis.

Wolfe, S. (2016). Studies related to β-lactam compounds. Current Trends in Organic Synthesis, pp. 101.

Penicillin

Therapeutic: anti-infectives

Pharmacologic: penicillins

Majority of gram positive and few gram negative

Bind to bacterial cell wall and prevents the formation of peptidoglycan layer via inhibiting transpeptidoglycan biosynthesis. It prevents the cross-linking of the peptidoglycan layer

Clarke, H. T. (Ed.). (2015). Chemistry of Penicillin. Princeton University Press.

Polymyxin B

Lipopolypeptide antibiotic

Gram negative

Interacts with the anionic lipopolysaccharide layers of the outer membrane of gram negative bacteria. This increases the cell permeability via displacement of magnesium and calcium ions which promotes cell death via the leakage of the cell contents

Sandri, A. M., Landersdorfer, C. B., Jacob, J., Boniatti, M. M., Dalarosa, M. G., Falci, D. R., ... & Nation, R. L. (2013). Population pharmacokinetics of intravenous polymyxin B in critically ill patients: implications for selection of dosage regimens. Clinical infectious diseases, vol. 57(4), pp. 524-531. https://doi.org/10.1093/cid/cit334

Vancomycin

Therapeutic: Antiinfectives, glycopeptide

Gram positive

Inhibits bacterial cell wall formation in the second stage of bacterial cell wall biosynthesis. It also alters the permeability of the bacterial cell wall and selectively inhibits the mechanism of ribonucleic acid biosynthesis

Arias, C. A., & Murray, B. E. (2012). The rise of the Enterococcus: beyond vancomycin resistance. Nature Reviews Microbiology, vol. 10(4), pp. 266-278.

Tetracycline

Therapeutic: Antiinfectives

Pharmacologic: tertacyclins

Gram positive

Inhibits bacterial protein synthesis via binding with the 30S bacterial ribosome

Nguyen, F., Starosta, A. L., Arenz, S., Sohmen, D., Dönhöfer, A., & Wilson, D. N. (2014). Tetracycline antibiotics and resistance mechanisms. Biological chemistry, vol. 395(5), pp. 559-575. https://doi.org/10.1515/hsz-2013-0292

Sulfisoxazole

 Therapeutic:anti-infectives, antiprotozoals

Gram positive

Inhibits at metabolism pathway of folic acid via interfering with the dyhydropteroate synthesase

· Nasr, T., Bondock, S., & Eid, S. (2016). Design, synthesis, antimicrobial evaluation and molecular docking studies of some new 2, 3-dihydrothiazoles and 4-thiazolidinones containing sulfisoxazole. Journal of enzyme inhibition and medicinal chemistry, vol. 31(2), pp. 236-246. https://dx.doi.org/10.3109/14756366.2015.1016514

Trimethoprim

Therapeutic:anti-infectives, antiprotozoals, folate antagonist

Gram positive and gram negative aerobic bacteria

Inhibits folic acid biosynthesis and cause a depression in the mechanism of hamatopoiesis. It is a pyrimidine inhibitor of dihydrofolate reductase.

Luo, X., Zheng, Z., Greaves, J., Cooper, W. J., & Song, W. (2012). Trimethoprim: Kinetic and mechanistic considerations in photochemical environmental fate and AOP treatment. Water research, vol. 46(4), pp. 1327-1336. https://doi.org/10.1016/j.watres.2011.12.052