Question

Explain, using the illustrations on page 155 of your text, why penicillin, once a widely used and effective antibiotic, is now no longer effective against penicillin-resistant bacteria.

Answer 1

Antibiotics such as penicillin have been key to the decline of infectious diseases over the last 60 years, but bacteria are becoming increasingly resistant to existing drugs.

Antibiotic resistance occurs when an antibiotic has lost its ability to effectively control or kill bacterial growth; in other words, the bacteria are "resistant" and continue to multiply in the presence of therapeutic levels of an antibiotic.

Some bacteria can become resistant to penicillin by producing beta-lactamase, a bacterial enzyme that destroys the beta-lactam ring of penicillin and makes it ineffective. One common example is Staphylococcus aureus, which produces high levels of beta-lactamase and causes infections in the blood, skin, or lungs.

That means many antibiotics are no longer effective at combating common diseases.

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penicillin is becoming obsolete in some developing countries, as well as in France, Spain and Romania, because of over-prescription by doctors and pharmacists. The emergence of "superbugs" such as methicillin-resistant staphylococcus aureus (MRSA) is causing the growing problem of hospital-acquired infections.

Antibiotic resistance is a much more important situation than swine flu and it will only get worse.

The doctors are commonly misdiagnosing viral infections as bacterial infections, and then prescribing antibiotics to treat them, while in some countries pharmacists are selling antibiotics without a doctor's prescription. Excessive use of antibiotics encourages the emergence of resistant bacteria.

antibiotic resistance is a global problem, with diseases including childhood pneumonia, dysentery and tuberculosis (TB) no longer responding to first-line antibiotics in some parts of the world.

"We've got to a situation where there are no more drugs for certain conditions. There are some people with extreme drug-resistant TB and there are no drugs to treat them,"