What is the strongest antibiotic?
There is no one single ‘strongest antibiotic’ that treats all infections.
Also antibiotics don’t really come in different strengths. They are many different ones and many are only effective against certain bacteria. So it is about doctors choosing the right one for your infection at the right dose and in the right form etc.
The following antibiotics can be used as drugs of last resort especially for serious rare infections. They are therefore almost always used intravenously in hospital.
Aminoglycosides – e.g. gentamicin – their use is extremely restricted due to risk of hearing loss and kidney damage. There have been almost no cases of resistance to gentamicin.
Blood levels should be measured to determine the correct dose.
Many are ‘stronger’ in the way that fewer bacteria are resistant to them. Therefore it’s best they are used infrequently, or they will also develop resistance to them.
Amphotericin B — used for life-threatening fungal infections and primary amoebic meningoencephalitis; its side effects are often severe or potentially fatal.
Carbapenems (such as imipenem/cilastatin) — used as a drug of last resort for a variety of bacterial infections.
Ceftobiprole and ceftaroline — fifth-generation cephalosporins active against methicillin-resistant Staphylococcus aureus (MRSA); use is limited to prevent development of drug resistance.
Cefiderocol — a cephalosporin used to treat complicated urinary tract infections (cUTI) caused by multi-drug resistant Gram-negative bacteria in patients with limited or no alternative options.
Chloramphenicol — formerly first-line therapy for Rocky Mountain spotted fever (until doxycycline became available).
Also first-line therapy (used topically) for bacterial conjunctivitis, and systemically for meningitis when allergies to penicillin or cephalosporin exist.
Unacceptably high risk of irreversible, fatal aplastic anaemia and gray baby syndrome causes intravenous chloramphenicol to be a drug of last resort.
Colistin — used against certain life-threatening infections, such as those caused by Pseudomonas; carries risk of kidney and nerve damage.
Linezolid — use is limited due to high cost and risk of vision loss or myopathy (due to mitochondrial damage).
Tigecycline – used to kill Acinetobacter and Legionella species; this drug is limited by high cost and risk of liver injury.
Vancomycin – is a glycopeptide antibiotic medication used to treat a number of bacterial infections – especially caused by methicillin-resistant Staphylococcus aureus.
It is used intravenously (injection into a vein) as a treatment for complicated skin infections, bloodstream infections, endocarditis, bone and joint infections, and meningitis.
Blood levels should be measured to determine the correct dose.
Summary
We have answered the question, ‘what is the strongest antibiotic?’ There isn’t one. There are different ‘stronger’ antibiotics for different infections.
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