Why is polymyxin only used on the skin

The antibiotic is metabolized by the bacterium, providing more energy for growth of the cell. Consider a Kirby-Bauer disk-diffusion assay. If you put penicillin and streptomycin disks adjacent to one another, the zone of inhibition is greater than that obtained by either disk alone. Print Images. MCB 20 1. What is meant by selective toxicity?

Chemotherapeutic agents should work on certain types of pathogens. Chemotherapeutic agents should work on many different targets on a pathogen. Chemotherapeutic agents should have only one mode of action. Chemotherapeutic agents should act against the pathogen and not the host. They are less expensive that other chemotherapeutic agents. The drugs also work against DNA gyrase. Bacteria are especially sensitive to these compounds.

Humans and other animal hosts lack peptidoglycan cell walls. Why is polymyxin only used on the skin? It has no effect on bacteria that live in the GI tract.

It can disrupt the metabolic pathways found in humans. It is sensitive to degradation by acid, making oral delivery unsuitable. Quinolones and fluoroquinolones act against what bacterial target? Bacterial ribosomes B. Cell walls C. DNA gyrase D. Metabolic pathways unique to bacteria E. Cell membranes. Why is it difficult to find good chemotherapeutic agents against viruses?

Viruses are not cells, and therefore not sensitive to such compounds. Viruses infect both bacteria and human cells.

There is no effective way to deliver the drug to the virus. How do antifungal drugs such as miconazole and amphotericin B function? Which of the following is an antiprotozoan drug that interferes with anaerobic metabolism? It produces a modified version of the molecule that is targeted by the drug. The bacteria are able to prevent entry of the drug into the cell.

It has an enzyme that destroys methicillin. It actively pumps the antibiotic out of the cell. Why is it more difficult to treat viral infections than it is to treat bacterial infections? Viruses have cell walls. Viruses are smaller than human cells. Viruses use the host cell's processes to carry out their own reproduction. Viruses are very similar to human cells. Which antibiotic is overcome by beta-lactamases? Tetracycline B. Sulfonamide C. Penicillin D. Tetracycline, Penicillin, and Sulfonamide are all affected by beta-lactamase.

How might efflux pumps increase antibiotic resistance in bacteria? Resistant bacteria may have a greater number of efflux pumps on their cell surfaces. Some bacteria can change the chemical structure of the antibiotic. Efflux pumps can never be modified to increase antibiotic resistance. Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps. Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what?

We may infer that PMB-iSH is possibly related to drug-induced hypersensitivity reaction, which is caused by the release of histamine and characterized as a symptom of rash and erythra. Secondly, based on our literature review, PMB-iSH mostly occurs on the skin of the head, neck and upper body. But in our case, not only did SH occur in the aforesaid locations, but also more serious symptoms were seen on the skin of the lower body and limbs.

Both clinicians and pharmacists should attach great importance to it. With the pathological mechanism still unclear, one of its probable reasons is associated with the release of histamine. Once PMB-iSH was observed, we should weigh the advantages and disadvantages of using PMB, and keep balance between curative effects and adverse event by such measures as dosage adjustment, cessation of drug administration and change to alternative antibiotics.

Overall, further investigation is warranted. Dereure O. Drug-induced skin pigmentation. Epidemiology, diagnosis and treatment. Am J Clin Dermatol. Krause W. Drug-induced hperpigemntation: a systematic review.

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Ann Pharmacother. Histopathological findings of pigmented lesion and recovery of natural skin colour in a patient with polymyxin B-associated diffuse hyperpigmentation. Download references. SHDC and Important and weak discipline construction plan for health and family planning system of Shanghai No. You can also search for this author in PubMed Google Scholar. GHZ and JH conceived and designed this study. ZQC and EQM made substantial contributions to acquisition of data, and involved in drafting the manuscript.

GHZ and LC wrote the paper. EZC made substantial contributions to acquisition, analysis and interpretation of the data, supported the present study with national fundings, and provided the analysis tools. JH and EZC reviewed and revised the manuscript critically for important intellectual content, and approved the final version.

All authors read and approved the manuscript. Correspondence to Erzhen Chen or Juan He. One patient was enrolled in the study and informed consent forms were signed by this patient. Written informed consent was obtained from the patient to the publication of this case report. A copy of the written informed consent is available for the review by the editor of this journal.

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BMC Pharmacol Toxicol 19, 41 Download citation. Received : 27 February Accepted : 20 June Published : 04 July Anyone you share the following link with will be able to read this content:.

Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative. Skip to main content. Search all BMC articles Search. Download PDF. Abstract Background Polymyxin B PMB , which is regarded as the ultimate antibacterial treatment against some intractable gram-negative bacteria with its outstanding anti-bacterial activities, inflicts several adverse effects on patients.

Case presentation A year-old female patient with sepsis received the administration of PMB by intravenous injection for the treatment of multi-drug resistant Klebsiella pneumoniae MDR-KP infection. Background Skin hyperpigmentation SH is a common type of skin disease with various inducing factors. Occurrence of PMB-iSH After the adjustment for the treatment, her body temperature dropped to normal and remained stable.

Hyperpigmentation in the head and face. Full size image. Hyperpigmentation in the lower abdomen. Hyperpigmentation in the right hand. Hyperpigmentation in the right foot. Treatment timeline of this patient. References 1. PubMed Google Scholar 3. Article PubMed Google Scholar 8.