Bacterial infections: causes, symptoms & treatment

Bacterial infections can range from a mild sore throat to life‑threatening pneumonia. They’re caused by many types of bacteria, and the right response depends on where the infection is and how severe it is. This page gives clear, practical information you can use today—how to spot common signs, when antibiotics help, how resistance works, and simple prevention tips.

Common bacterial problems you’ll hear about often: strep throat, urinary tract infections (UTIs), skin infections like cellulitis, bacterial pneumonia, and some ear or sinus infections. Symptoms vary: fever, localized pain, redness and swelling, cough with colored sputum, burning when peeing, or a swollen lymph node near a sore area. If symptoms appear quickly and get worse over 24–48 hours, treat seriously.

Diagnosis usually starts with your history and a physical exam. Doctors may do lab tests—throat swabs, urine tests, wound swabs, or bloodwork—to confirm which bacterium is causing trouble. Cultures and rapid tests help pick the right antibiotic instead of guessing.

Antibiotics can be lifesaving when used correctly. They only work on bacteria, not viruses. That means antibiotics won’t help with viral colds or the flu. Take antibiotics exactly as prescribed, finish the full course unless your doctor says otherwise, and don’t save leftovers for later. Misusing antibiotics fuels antibiotic resistance—bugs that no longer respond to common drugs.

If a first‑line antibiotic fails or if resistance is suspected, doctors will switch drugs or use targeted options. For a deeper read on alternatives when common meds fail, see our guide on 10 Best Amoxicillin Alternatives for Resistant Infections and Minocycline Alternatives. Those pages explain when to consider alternatives and why specialist input matters.

When to see a doctor

Get medical help if you have any of these: a high or persistent fever, breathing trouble, severe pain, rapid spreading redness on skin, confusion, bloody urine, or an infection that doesn’t improve after 48–72 hours on antibiotics. New or worsening shortness of breath, chest pain, fainting, or signs of sepsis (very low blood pressure, fast heartbeat, extreme weakness) need emergency care right away.

Practical prevention tips

Preventing bacterial infections often means simple daily choices: wash hands thoroughly, keep wounds clean and covered, cook food to safe temperatures, avoid close contact with sick people, and stay current on vaccines like tetanus or pneumococcal shots if you’re in a risk group. For UTIs, stay hydrated and follow safe sexual practices. For wounds, clean and monitor for increasing redness, pus, or fever.

If you’re unsure about symptoms or antibiotic choices, contact a healthcare provider. You can also use our site to find detailed articles, drug info, and guides to help you ask the right questions at your appointment.