Researchers from the University of California, San Diego and Trius Therapeutics, a biopharmaceutical company that develops antibiotics, have discovered a new marine microorganism within the mud along the coast of Santa Barbara, Calif. Culture extracts from this new species of Streptomyces are able to destroy anthrax and various gram-positive bacteria; using a technique of chlorination renders it somewhat effective against some gram-negative bacteria. The researchers have named the antibiotic 'Anthracimycin' and the microorganism 'Actinomycete.'

"The discovery of truly new chemical compounds is quite rare," Dr. William Fenical, lead researcher and professor of oceanography, said to BBC. "This discovery adds to many previous discoveries that show that marine bacteria are genetically and chemically unique."

In its chemical structure, Anthracimycin is unusual, according to the researchers. Unlike current antibiotics, it is able to kill gram-positive bacteria like Staphylococci, Enterococci, and Streptococci that are usually found to be resistant. By creating different compounds from the microorganism, the researchers are hoping to develop effective new drugs that may be effective against gram-negative bacteria, including methicillin-resistant Staphylococcus aureus.

Resistance

Increasingly, multidrug-resistant organisms (MDROs) are found in hospitals and long-term care facilities and are the cause of life-threatening infections. Widespread and long use of antibiotics — they have been around since the 1940s — as well as the natural adaptation and growth of bacteria have led to the current prevalence of MDROs. Although the most famous of these, so to speak, may be methicillin-resistant Staphylococcus aureus (MRSA), other gram-negative bacteria are potentially worse. Add to this the fact that resistance caused by overuse of an antibiotic in one part of the world is often spread globally at very fast rates. Colonization without infection — becoming sick — often occurs and contributes to rapid diffusion.

Although transmission generally occurs through hospital personnel who have not thoroughly cleaned their hands, spread of bacteria is also an environmental issue within hospitals. In a recent outbreak, according to The New England Journal of Medicine, klebsiella, a gram-negative bacteria, "survived on a ventilator that had been cleaned three times with two different disinfectants. Environmental services personnel are as much a part of the MDRO containment net as doctors and nurses."

Along with these, scientists are discovering other sources to the problem of antibiotic resistance. In a recent paper, researchers found that urban wastewater treatment plants (UWTPs) "are among the main sources of antibiotics' release into the environment." A team of scientists from Italy, France, Portugal, Germany, and Cyprus reviewed the processes and technologies used within USTPs, including advanced treatment and disinfection, in order to understand how antibiotics disseminated within the environment promote the "selection of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB)," as they wrote. Although "advanced treatment technologies and disinfection process are regarded as a major tool to control the spread of ARB into the environment," the underlying biological mechanisms that contribute to the development and selection of antibiotic resistant genes and bacteria have never been adequately understood.

Perhaps nothing could be more frightening than the thought of bacteria adapting to our chemical 'weaponry' and growing increasingly resistant, yet Anthrax, which has been used as a biological weapon, also gives rise to fears.

Anthrax

A dangerous infectious disease, Anthrax is caused by the spore-forming bacterium Bacillus anthracis and may cause symptoms within seven days or take as long 42 days to appear. In 2001, within weeks of the September 11 attacks, an 'assault' mounted via letters containing spores — dormant cells that come to life under the right conditions — caused 22 cases of infection and five deaths in the United States.

According the the Centers for Disease Control and Prevention, the three types of anthrax — skin (cutaneous), lungs (inhalation), and digestive (gastrointestinal) — cannot be spread from one person to another, rather only from animals to humans or direct contact with the spores.

A cutaneous infection first appears as a small sore that develops into a blister, which then develops into an ulcer, all of which do not cause pain. The identifying mark of the skin ulcer is a black area in the center. Gastrointestinal infection causes nausea, loss of appetite, bloody diarrhea, and fever, followed by bad stomach pain. When anthrax is inhaled, cold or flu-like symptoms will develop. Following these relatively mild symptoms, including sore throat, fever, and muscle aches, are more severe symptoms, such as chest discomfort, shortness of breath, tiredness, and muscle aches. Inhalation and generally respiratory infection are the most severe and dangerous forms of anthrax infection with the highest rates of death.

Gastrointestinal anthrax is less serious. Still, the proportion of deaths in cases caused by such infection ranges between one-quarter and slightly more than half. Cutaneous anthrax is the least serious; early treatment with antibiotics will cure cutaneous anthrax most of the time, and even among those who are not treated, nearly 80 percent of those infected cutaneously do not die.

Although a vaccination exists, it is not publicly available. Discovery of a new antibiotic that is effective against anthrax infection, then, is significant. Perhaps marine mud from the area of the California coast, given top billing as the 'American Riviera,' will yield even more medicines?

 

Source: Rizzo L, Manaia C, Merlin C, et al. Urban wastewater treatment plants as hotspots for antibiotic resistant bacteria and genes spread into the environment: A review. Science of the Total Environment. 2013.

Sandora TJ, Goldmann DA. Preventing Lethal Hospital Outbreaks of Antibiotic-Resistant Bacteria. The New England Journal of Medicine. 2012.

Fenical, W. Anthracimycin, a Potent Anthrax Antibiotic from a Marine-Derived Actinomycete, Angewandte Chemie International Edition. 2013.