Antibiotics for intestinal bacterial infection

Treatment depends on the suspected organism, severity of illness, medical history and test results. In certain infections, an antibiotic offers little benefit or can increase the chance of complications, so self-treatment with leftover medicine is unsafe.

Diarrhoea, cramps, nausea and fever may come from bacteria, viruses, parasites, medicines or non-infectious bowel conditions. Symptoms alone may not identify the cause. Recent travel, food exposure, antibiotic use, illness among close contacts and blood or mucus in stool can guide testing.

A stool sample may be requested when illness is severe, persistent or otherwise concerning. The result can identify whether an antibiotic is appropriate and which one may work. Giardiasis is an intestinal infection caused by a parasite rather than a bacterium, although it is treated with specific antimicrobial medicine.

Replace lost fluid with frequent drinks; an oral rehydration solution can also replace salts. Continue light food as tolerated. Wash hands thoroughly after using the toilet and before handling food, and avoid preparing meals for others while diarrhoea or vomiting continues.

Do not start an antibiotic or an anti-diarrhoeal medicine without advice when stool contains blood, fever is present or abdominal pain is strong. If treatment is prescribed, follow its instructions and tell the clinician about allergies, pregnancy, kidney or liver disease, and recent antibiotic courses.

Seek urgent help for blood or black stool, severe or worsening abdominal pain, a swollen rigid abdomen, confusion, fainting, or inability to keep fluids down. Very little urine, extreme thirst, unusual drowsiness or dizziness on standing can indicate significant dehydration.

Prompt assessment is also needed when symptoms are worsening in an older adult, a young child, during pregnancy, or in someone with weakened immune defences. Breathing difficulty or swelling of the face or throat after an antibiotic is an emergency.

Ask whether a stool test is appropriate, what signs of dehydration to watch for, whether your usual medicines should continue, and how to reduce transmission at home. If an antibiotic is recommended, ask what change should trigger reassessment.