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Antibiotic Resistance

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Antibiotic Resistance
Antibiotic Resistance

Staphylococcus aureus (Staph Bacteria)

Janice Haney Carr/CDC

Antibiotic Resistance

Antibiotic resistance is becoming more and more common. Antibiotics and antimicrobial agents are drugs or chemicals that are used to kill or hinder the growth of bacteria, viruses, and other microbes. Due to the prevalent use of antibiotics, resistant strains of bacteria are becoming much more difficult to treat. These "super bugs" represent a threat to public health since they are resistant to most commonly used antibiotics.

Current antibiotics work by disrupting so-called cell viability processes. Disruption of cell membrane assembly or DNA translation are common modes of operation for current generation antibiotics. Bacteria are adapting to these antibiotics making them ineffective means for treating these types of infection. For example, Staphylococcus aureus have developed a single DNA mutation that alters the organism's cell wall. This gives them the ability to withstand antibiotic cell disruption processes. Antibiotic resistant Streptococcus pneumoniae produce a protein called MurM, which counteracts the effects of antibiotics by helping to rebuild the bacterial cell wall.

Fighting Antibiotic Resistance

Researchers are attempting to develop new types of antibiotics that will be effective against resistant strains. These new antibiotics would target the bacteria's ability to become virulent and infect the host cell. Researchers at Brandeis University have discovered that bacteria have protein "switches" that when activated, turn "ordinary" bacteria into pathogenic organisms. These switches are unique in bacteria and are not present in humans. Since the switch is a short-lived protein, elucidating its structure and function was particularly difficult. Using nuclear magnetic resonance (NMR) spectroscopy, the researchers were able to regenerate the protein for one and one half days. By extending the time frame that the protein was in its "active state," the researchers were able to map out its structure. The discovery of these "switches" has provided a new target for the development of antibiotics which focus on disrupting the activation of the protein switches.

Monash University researchers have demonstrated that bacteria contain a protein complex called Translocation and Assembly Module (TAM). TAM is responsible for exporting disease causing molecules from the inside of the bacterial cell to the outer cell membrane surface. TAM has been discovered in several antibiotic resistant bacteria. The development of new drugs to target the protein would inhibit infection without killing the bacteria. The researchers contend that keeping the bacteria alive, but harmless, would prevent the development of antibiotic resistance to the new drugs.

Researchers from the NYU School of Medicine are seeking to combat antibiotic resistance by making resistant bacteria more vulnerable to current antibiotics. They discovered that bacteria produce hydrogen sulfide as a means to counter the effects of antibiotics. Antibiotics cause bacteria to undergo oxidative stress, which has toxic effects on the microbes. The study revealed that bacteria produce hydrogen sulfide as a way to protect themselves against oxidative stress and antibiotics. The development of new drugs to target bacterial gas defenses could lead to the reversal of antibiotic resistance in pathogens such as Staphylococcus and E.coli.

These studies indicate how highly adaptable bacteria are in relation to the application of antimicrobial treatments. Antibiotic-resistant bacteria have become a problem not only in hospitals, but in the food industry as well. Drug-resistant microbes in medical facilities lead to patient infections that are more costly and difficult to treat. Resistant bacteria in turkey and other meat products have caused serious public health safety issues. Some bacteria may develop resistance to a single antibiotic agent or even multiple antibiotic agents. Some have even become so resistant that they are immune to all current antibiotics. Understanding how bacteria gain this resistance is key to the development of improved methods for treating antibiotic resistance.

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