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What-is-gentamicin-used-to-treat

What is gentamicin used to treat?

Posed on  December 22, 2020, edited by Jason, category  

What is gentamicin?

1. Definition

Gentamicin is one of the few thermostable antibiotics, so it is widely used in media preparation. This broad-spectrum antibiotic independently developed by China is one of the greatest scientific and technological achievements since the founding of New China. It was first developed in 1967 and was successfully identified at the end of 1969. It was named "Gentamicin", which means celebrating the "Ninth Congress" and the greatness of the working class.

Gentamicin is extracted from the fermentation broth of Monospores of Actinomycetes. It is a alkaline compound and is a commonly used aminoglycoside antibiotic. It is mainly used to treat bacterial infections, especially infections caused by Gram-negative bacteria. Gentamicin can bind to the 30s subunit of the bacterial ribosome and block bacterial protein synthesis.

BALLYA provides a gentamicin test to tell you if there are gentamicin residues in dairy products you eat every day.

what-is-gentamicin
what-is-gentamicin

2. History

Wang Yue, whose infant name is Zhongwu, was born in Minhou County (now Fuzhou), Fujian. He was born in Tongming Lane, Shangdu in August 1915. His family had a Wang Dasheng's cigarette shop with a history of more than 200 years. His father, Ainlu, was a scholar in the late Qing Dynasty. Ainlu, a well-known literatus in Fuzhou, was famous for his writing and calligraphy. He participated in the Revolution of 1911 in his early years and served as secretary of the Provincial Construction Department and the Finance Department after the restoration.

Wang Yue was upright, honest, hard-working, and enterprising just like his farther. At the age of twelve (1927), he studied at Fuzhou Yinghua Middle School. In 1929, he transferred to Fuzhou Sany Middle School where he studied hard and ranked among the best.

In August 1941, he was recommended by U.S. Ambassador to China Stuart to go to the Graduate School of Logus University in New Jersey, USA for further study. Under the guidance of the famous Nobel Prize winner, antibiotic research pioneer, and discoverer of streptomycin and neomycin, Professor Wagsman, he completed all the research topics after three years of hard work and achieved excellent results in 1943 Ph.D. in microbiology, received the Golden Key Award from the SIGMX Society, and was hired as a researcher at Merck Pharmaceuticals Institute of Chemical Therapy.

During his studies in the United States, his tutor Professor Waggsman highly valued him and advised him to stay in the United States to engage in microbiology Research work and provide him with favorable employment and scientific research conditions. But he believed that he has the responsibility and obligation to return to the motherland and devoted himself to the development of science in the motherland. Driven by the anti-Japanese and national salvation wave overseas in the United States that broke out in September 1943, he returned China in 1944 with enthusiasm for serving the motherland.

In the early days of liberation, imperialists imposed a complete blockade on China, and imposed an embargo for antibiotics on China. At that time, it was the golden age of antibiotic research and production in various countries in the world, while there was an extreme shortage of antibiotics in China. At this critical moment, Wang Yue felt that he had the responsibility to share the worries for the country and the people, and was determined to fill the gap in medicine in the motherland.

In 1965, he first proposed the research field of finding new antibiotics from Micromonospora in China. In 1966, he and his assistants isolated the well-known gentamicin-producing bacteria from Micromonospora, and officially put it into production on the 20th anniversary of the founding of the People’s Republic of China in 1969. According to statistics, from the start of production to 1985, there were 40 factories across the country producing 868 tons with an output value of more than 1 billion yuan. The discovery of gentamicin has pushed the research and production of antibiotics in China to a new stage, and has made significant contributions to the Chinese medical industry.

3. Pharmacological effects

Gentamicin is an aminoglycoside drug. Gentamicin mechanism of action is to act on ribosomes in bacteria, inhibit bacterial protein synthesis, and destroy the integrity of bacterial cell membranes. Gentamicin can first diffuse through the porins of the outer cell membrane through passive diffusion, then enter the cell through the cell membrane by the transport system, and irreversibly bind to the isolated ribosomal 30S subunit, leading to the destruction of the A site, and then:

  • Prevent the correct positioning of ammonia tRNA at position A, especially hinder the binding of methionyl tRNA, thereby interfering with the assembly of functional ribosomes and inhibiting the formation of 70S initiating complex.
  • Induce the mismatch between tRNA and mRNA code triplet, causing the 30S subunit of the intact ribosome to misread the genetic code, causing the wrong amino acid to be inserted into the protein structure, leading to abnormal and non-functional protein synthesis.
  • It prevents the termination factor from binding to the A site, so that the synthesized peptide chain cannot be released, and prevents the dissociation of the 70S intact ribosome.
  • It hinders the depolymerization and assembly process of polyribosomes, causing the ribosome in the bacteria to be depleted. Gentamicin has strong antibacterial activity against Pseudomonas aeruginosa, Proteus (indole positive and negative), Escherichia coli, Klebsiella, Enterobacter, Serratia, Shigella, Citrobacter, Neisseria, Staphylococcus aureus (excluding methicillin-resistant strains). Gentamicin is ineffective against Streptococcus (including Streptococcus pyogenes, Pneumococcus, Streptococcus faecalis, etc.), anaerobic bacteria (Bacteroides), Mycobacterium tuberculosis, Rickettsia, viruses and fungi.

4. Gentamicin Uses

  • For the treatment of neonatal sepsis and sepsis caused by sensitive bacteria.
  • It is suitable for the treatment of respiratory tract infections, peritonitis, biliary tract infections caused by sensitive bacteria.
  • Suitable for the treatment of genitourinary system infections caused by sensitive bacteria (except for initial treatment of simple urinary tract infections).
  • Suitable for the treatment of skin and soft tissue infections, burn infections caused by sensitive bacteria.
  • Oral treatment can be used for intestinal infection or colon surgery preparation
  • Intramuscular injection combined with clindamycin or metronidazole can be used to reduce the incidence of infection after colon surgery.
  • Intrathecal injection can be used as an adjuvant treatment for severe central nervous system infections (acute purulent meningitis, ventriculitis) caused by Pseudomonas aeruginosa or Staphylococcus.
  • Gentamicin can also be used to treat listeriosis.
  • Gentamicin eye drops are suitable for conjunctivitis, keratitis and tears caused by coagulase-negative and positive Staphylococcus, Pseudomonas aeruginosa, Escherichia coli, Pneumoniae and other Gram-negative bacilli and Neisseria Bunchitis, blepharitis, meibomitis, etc.

Gentamicin Dosage

  1. For intestinal infection or preoperative preparation, 80-160 mg each time, 3 to 4 times a day.
  2. Intramuscular injection: general dose: 80 mg (80,000 units) each time, 2 to 3 times a day, 8 hours apart; or 1 to 1.7 mg/kg, once every 8 hours; 7 to 14 days in total. Simple urinary tract infection: body weight less than 60 mg, 3 mg/kg each time, once a day; weight over 60 mg, 160 mg each time, once a day; or 1.5 mg/kg each time, once every 12 hours.
  3. Intravenous drip: The dose is the same as intramuscular injection; each dose is added to 50~200ml of 0.9% saline or 5% glucose solution so that the drug concentration does not exceed 1g/L (base) (equivalent to 0.1% solution), slowly drip in 30-60min.
  4. Intrathecal or intracerebroventricular injection: 4-8mg each time, once every 2-3 days. Draw each dose (concentration of 2g/L) into a 5ml or 10ml sterile syringe. After lumbar puncture, take a sample of cerebrospinal fluid and send it to the laboratory for examination, and then put the syringe containing gentamicin Connect the lumbar puncture needle, make a considerable amount of cerebrospinal fluid flow into the syringe, push while pumping, and then slowly inject all the liquid in the syringe within 3 to 5 minutes. When injecting the medicine, the lumbar puncture needle should be slightly inclined upward, if cerebrospinal fluid is purulent and not easy to flow out, gentamicin can also be diluted with saline injection.
  5. Dose during dialysis: After hemodialysis, according to the severity of the infection, a dose of 1 to 1.7 mg/kg can be given according to body weight.

Precautions

  1. Blood drug concentration should be monitored, especially in neonates, elderly and patients with renal insufficiency.
    The effective therapeutic concentration of gentamicin ranges from 4 to 10μg/ml. It should be avoided that the peak plasma concentration continues to be above 12μg/ml and the trough concentration exceeds 2μg/ml. However, due to individual differences in patients in surgery, gynecology, obstetrics, or burns, the calculated dose may be lower than the minimum commonly used dose or higher than the maximum commonly used dose. Patients receiving intrathecal gentamicin injections should also monitor the drug concentration in the cerebrospinal fluid.
  2. When the blood drug concentration cannot be determined, the dose should be adjusted according to the measured creatinine clearance rate.
  3. After the first saturated dose (1~2 mg/kg) is given, the maintenance dose for patients with renal insufficiency, vestibular function or hearing loss should be reduced: the dose remains the same, but the dosing interval should be extended; or the dosing interval does not change, and reduce or stop gentamicin each time. Since gentamicin is not metabolized in the body, but excreted through urine, so patients with impaired renal function may cause the drug accumulation to a toxic concentration.
  4. Patients should be given adequate water to reduce renal tubular damage.
  5. Long-term application may lead to overgrowth of resistant bacteria.
  6. It has the effect of inhibiting respiration, so intravenous injection is not allowed. It is ineffective for streptococcal infection. Upper respiratory tract infections caused by streptococci should not be used.

Gentamicin Side Effects

  1. It has been reported that the systemic application of gentamicin combined with intrathecal injection causes leg twitching, skin rash, fever and body spasms. The incidence of renal dysfunction caused by gentamicin is higher than that of tobramycin.
  2. Most people have hearing loss, tinnitus or fullness of the ears (ototoxicity), hematuria, a significant reduction in the frequency of urination or a decrease in urine output, loss of appetite, extreme thirst (renal toxicity), unstable walking, and dizziness (Ototoxicity, affecting the vestibule; nephrotoxicity). Those with a lower incidence have dyspnea, lethargy, and extreme weakness (neuromuscular block or nephrotoxicity).
  3. If hearing loss, tinnitus, or fullness of the ears occurs after stopping the drug, attention should be paid. The adverse reaction is similar to that of kanamycin, and the reaction is lighter when the dosage is small. If the dosage is large, the course of treatment is long, and the intestinal flora is disturbed occasionally, once you stop the drug, you can be normal again.
    In individual cases, numbness, dizziness, and tinnitus in the skin of the mouth, face and limbs may occur. Occasionally, the main symptoms are respiratory obstruction and circulatory disorders, more than half of the cases died after rescue failure, so some people think that the product is the most serious adverse reaction is immediate anaphylactic shock, which can cause poisoning symptoms of Romberg's disease (difficult to stand with closed eyes, unsteady standing in the dark).
  4. Large-dose medication can easily cause edema. Large-dose use can cause urinary obstruction, acute renal failure, and neurological symptoms. Inhaling it can cause allergic reactions and asthma. Gentamicin eye drops can cause edema, toxic conjunctivitis. This product can occasionally cause respiratory depression, reports have been reported at home and abroad. The product can occasionally cause polyneuropathy and toxic encephalopathy. Allergic reactions are rare, and occasional skin itching and urticaria, etc. may appear once in a while, which generally do not affect the continued application, and will disappear quickly after the drug is stopped.
  5. The product causes allergic leukopenia and neutropenia occasionally. It can cause anemia, leukopenia, neutropenia, thrombocytopenia, and hypotension, and gastrointestinal discomfort such as nausea, loss of appetite, vomiting, and abdominal distension. A few patients may have liver function changes, such as elevated serum aminotransferase, positive flocculation reaction, etc.
gentamicin-test
gentamicin-test

Conclusion

Gentamicin has good stability and a wide range of efficacy. And more importantly, it is of great significance in the history of antibiotic discovery in China. However, gentamicin, like other antibiotics, has certain side effects, especially on hearing and liver and kidney function.

References

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