What Are Gram Negative Antibiotics?

Gram negative antibiotics are medications effective against infections with Gram negative bacteria like Escherichia coli. These infections can be difficult to treat, as the bacteria resist many common antibiotics, and rather than being treatable with a broad spectrum drug, it may be necessary to use a very specific formulation. This requires the doctor to conduct tests to find out which organism is causing the infection, rather than providing the patient with a basic antibiotic in the hopes that it will work.

The distinction between Gram negative and Gram positive bacteria depends on how they perform in a Gram stain, a laboratory test where a technician exposes the cells to crystal violet and then counterwashes them to see if they retain color. If the bacteria stain, they are Gram positive. Gram negative bacteria do not stain because of differences in the structure of their cell walls. These differences prove to be key to determining what kinds of antibiotics the organisms respond to. Gram positive organisms are more susceptible to antibiotics in general and are often treatable with broad spectrum drugs.

Designers of Gram negative antibiotics must develop drugs capable of punching through the cell membrane of Gram negative bacteria to deliver lethal medications to the organism, and each cell wall is different, making this challenging. The drugs may interfere with cell wall synthesis, bacterial reproduction, or metabolism, making it impossible for the organism to survive and breed to create a new generation of bacteria.

Bacteria associated with urinary, respiratory, and gastrointestinal tract infections are often Gram negative. Doctors treating such infections need to select appropriate Gram negative antibiotics to treat the patient's condition. If the doctor uses the wrong drug, the bacteria will not respond and the infection can get worse. Aminoglycoside antibiotics like streptomycin are examples of Gram negative antibiotics. Bacteria can still develop resistance to them over time as a result of poor habits while taking prescribed antibiotics.

Like other antibiotics, these drugs can cause side effects like nausea, headaches, and skin rashes. Patients may have allergic responses in some circumstances, in which case they will develop acute symptoms like difficulty breathing, skin blistering, and hives. If a patient appears to have an allergic response to Gram negative antibiotics, it is advisable to consult a doctor to get rapid treatment, including an alternative antibiotic to treat the patient without sparking another allergic response. If a patient has a history of adverse reactions, this will be noted in the chart to prevent accidental prescriptions for drugs the patient shouldn't take.