Gentamicin vs. Streptomycin

Attribute	Gentamicin	Streptomycin
Drug Class	Aminoglycoside Antibiotic	Aminoglycoside Antibiotic
Mechanism of Action	Inhibits bacterial protein synthesis	Inhibits bacterial protein synthesis
Spectrum of Activity	Broad-spectrum	Broad-spectrum
Common Uses	Treatment of severe bacterial infections	Treatment of tuberculosis and other bacterial infections
Administration	Usually given intravenously or intramuscularly	Usually given intravenously or intramuscularly
Side Effects	Nephrotoxicity, ototoxicity	Nephrotoxicity, ototoxicity
Resistance	Resistance can develop	Resistance can develop

Introduction

Gentamicin and Streptomycin are both antibiotics that belong to the aminoglycoside class. They are commonly used in the treatment of various bacterial infections. While they share some similarities in terms of their mechanism of action and spectrum of activity, there are also notable differences between the two drugs. This article aims to provide a comprehensive comparison of the attributes of Gentamicin and Streptomycin, shedding light on their similarities and differences.

Mechanism of Action

Gentamicin and Streptomycin exert their antibacterial effects by inhibiting protein synthesis in bacteria. They bind to the 30S subunit of the bacterial ribosome, preventing the formation of functional initiation complexes and leading to the misreading of mRNA. This ultimately results in the production of non-functional or toxic proteins, leading to bacterial cell death.

However, there is a slight difference in their mechanism of action. Gentamicin primarily acts by causing premature termination of protein synthesis, while Streptomycin primarily causes misreading of the genetic code. This difference in mechanism may contribute to variations in their efficacy against different bacterial strains.

Spectrum of Activity

Both Gentamicin and Streptomycin exhibit a broad spectrum of activity against various Gram-negative and some Gram-positive bacteria. They are particularly effective against aerobic bacteria, including Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter species.

However, Gentamicin has a slightly broader spectrum of activity compared to Streptomycin. It is also effective against some Gram-positive bacteria, such as Staphylococcus aureus and Streptococcus species. This broader spectrum of activity makes Gentamicin a preferred choice in certain clinical scenarios where both Gram-negative and Gram-positive bacteria are suspected.

Resistance

Resistance to Gentamicin and Streptomycin has become a significant concern in recent years. Bacteria can develop resistance through various mechanisms, including enzymatic modification of the drug, decreased drug uptake, and altered target sites.

However, Gentamicin is generally more susceptible to resistance compared to Streptomycin. This is partly due to the fact that Gentamicin is more commonly used in clinical practice, leading to a higher selective pressure for resistance. Streptomycin, on the other hand, is less frequently used, which may contribute to a lower prevalence of resistance.

It is important to note that the emergence of multidrug-resistant bacteria poses a challenge for both Gentamicin and Streptomycin. In such cases, combination therapy with other antibiotics may be necessary to achieve effective treatment outcomes.

Pharmacokinetics

Both Gentamicin and Streptomycin are primarily administered intravenously or intramuscularly due to their poor oral bioavailability. They exhibit similar pharmacokinetic properties, including a relatively short half-life and a predominantly renal excretion.

However, there are some differences in their pharmacokinetics. Gentamicin has a slightly longer half-life compared to Streptomycin, which allows for less frequent dosing. Additionally, Gentamicin is known to have a higher volume of distribution, indicating a greater tissue penetration compared to Streptomycin.

Adverse Effects

Both Gentamicin and Streptomycin are associated with potential adverse effects, primarily due to their mechanism of action and pharmacokinetic properties.

Gentamicin is known to have a higher risk of nephrotoxicity, especially when used at high doses or for prolonged durations. It can also cause ototoxicity, leading to irreversible hearing loss or balance disturbances. Other adverse effects may include allergic reactions, skin rash, and neuromuscular blockade.

Streptomycin, on the other hand, is more commonly associated with ototoxicity, particularly affecting high-frequency hearing. It can also cause nephrotoxicity, although the risk is generally lower compared to Gentamicin. Other potential adverse effects include dizziness, vertigo, and allergic reactions.

Clinical Applications

Gentamicin and Streptomycin find clinical applications in various infectious diseases, including respiratory tract infections, urinary tract infections, sepsis, and endocarditis.

Gentamicin is often used in combination with other antibiotics for the treatment of serious Gram-negative infections, such as pneumonia caused by Pseudomonas aeruginosa. It is also commonly employed in the management of urinary tract infections caused by Enterobacteriaceae.

Streptomycin, on the other hand, is less frequently used in clinical practice due to the availability of newer antibiotics. However, it still plays a role in the treatment of certain infections, such as tuberculosis and plague.

Conclusion

In conclusion, Gentamicin and Streptomycin are both valuable antibiotics with similar mechanisms of action and broad spectra of activity against various bacteria. While Gentamicin has a slightly broader spectrum of activity and is more susceptible to resistance, Streptomycin offers a lower risk of nephrotoxicity. Understanding the similarities and differences between these antibiotics is crucial for healthcare professionals to make informed decisions regarding their appropriate use in clinical practice.