Antibiotics are among the most frequently prescribed medications in modern medicine. Antibiotics cure disease by killing or injuring bacteria. The first antibiotic was penicillin, discovered accidentally from a mold culture. Today, over 100 different antibiotics are available to cure minor, as well as life-threatening infections.
Although antibiotics are useful in a wide variety of infections, it is important to realize that antibiotics only treat bacterial infections. Antibiotics are useless against viral infections (for example, the common cold) and fungal infections (such as ringworm). Your doctor can best determine if an antibiotic is right for your condition.
Most antibiotics have 2 names, the trade or brand name, created by the drug company that manufactures the drug, and a generic name, based on the antibiotic's chemical structure or chemical class. Trade names such as Keflex and Zithromax are capitalized. Generics such as cephalexin and azithromycin are not capitalized.
Though it looks like a tiny purple blowtorch, a pencil-sized plume of plasma on the tip of a small probe remains at room temperature as it swiftly dismantles tough bacterial colonies deep inside a human tooth. But it's not another futuristic product of George Lucas' imagination. It's the exciting work of USC School of Dentistry and Viterbi School of Engineering researchers looking for new ways to safely fight tenacious biofilm infections in patients - and it could revolutionize many facets of medicine.
Two of the study's authors are Chunqi Jiang, a research assistant professor in the Ming Hsieh Department of Electrical Engineering-Electrophysics, and Parish Sedghizadeh, assistant professor of clinical dentistry and Director of the USC Center for Biofilms. "Nanosecond Pulsed Plasma Dental Probe" appears in the June 2009 issue of Plasma Processes and Polymers.
Sedghizadeh explained that biofilms are complex colonies of bacteria suspended in a slimy matrix that grants them added protection from conventional antibiotics. Biofilms are responsible for many hard-to-fight infections in the mouth and elsewhere. But in the study, biofilms cultivated in the root canal of extracted human teeth were easily destroyed with the plasma dental probe, as evidenced by scanning electron microscope images of near-pristine tooth surfaces after plasma treatment.
Plasma, the fourth state of matter, consists of electrons, ions, and neutral species and is the most common form found in space, stars, and lightning, Jiang said. But while many natural plasmas are hot, or thermal, the probe developed for the study is a non-thermal, room temperature plasma that's safe to touch. The researchers placed temperature sensors on the extracted teeth before treatment and found that the temperature of the tooth increased for just five degrees after 10 minutes of exposure to the plasma, Jiang said.
The cooler nature of the experimental plasma comes from its pulsed power supply. Instead of employing a steady stream of energy to the probe, the pulsed power supply sends 100-nanosecond pulses of several kilovolts to the probe once every millisecond, with an average power less than 2 Watts, Jiang said.
