Navigation Links
Penicillin redux: Rearming proven warriors for the 21st century

Penicillin, one of the scientific marvels of the 20th century, is currently losing a lot of battles it once won against bacterial infections. But scientists at the University of South Carolina have just reported a new approach to restoring its combat effectiveness, even against so-called "superbugs."

Bacteria have been chipping away at the power of the penicillin family of drugs since their first wide-scale use as antibiotics in the 1940s. For example, the staph infection, brought about by the bacterium Staphylococcus aureus, was once readily treated with penicillin and its molecular cousins.

But that bug has changed. In the 1960s, a new strain arrived, termed MRSA for methicillin- (or sometimes multidrug-) resistant S. aureus. It has become a serious public health problem because the earliest deployed antibiotics are often useless against the new strain, and its prevalence has only increased since it was first observed. MRSA (pronounced mer-suh) is sometimes called a superbug because of the difficulty physicians have in treating infected patients.

The S. aureus microbe has evolved the MRSA strain by developing a variety of defenses against antibiotics to which they've been exposed. One of those defenses effectively neutralizes penicillin's greatest strength.

That strength is its molecular core, a cyclic four-membered amide ring termed a beta-lactam. It is a common structural element of the penicillins, their synthetic and semi-synthetic derivatives, and other related molecules that constitute the broad family of drugs called the beta-lactam antibiotics. Just a few examples (of dozens) include amoxicillin, ampicillin and cefazolin.

The beta-lactam structure in a molecule is something that many bacteria don't like at all. It greatly hinders their ability to reproduce by cell division, and so chemists have for years spent time making molecules that all contain the beta-lactam structural motif, but differ in the surrounding molecular "shrubbery." Physicians heavily use the many versions of beta-lactam antibiotics to fight bacterial infections, and many have been retired because they're no longer effective against the defenses bacteria have evolved in response.

One of the most effective bacterial defenses is an enzyme called beta-lactamase, which chews up the beta-lactam structure. Some bacteria, such as MRSA, have developed the ability to biosynthesize and release beta-lactamase when needed. It's a devastating defense because it's so general, targeting the common structural motif in all of the many beta-lactam antibiotics.

But that also creates the opportunity for a general approach to solving the problem, which is what Carolina's Chuanbing Tang and colleagues just reported in the Journal of the American Chemical Society.

"Instead of developing new antibiotics, here we ask the question, 'can we recycle the old antibiotics?' " he said. "With traditional antibiotics like penicillin G, amoxicillin, ampicillin and so on, can we give them new life?"

The approach pairs the drug with a protective polymer developed in Tang's chemistry laboratory. In lab tests, graduate student Jiuyang Zhang prepared a cobaltocenium metallopolymer that greatly slowed the destructiveness of beta-lactamase on a model beta-lactam molecule (nitrocefin).

The interdisciplinary team, which included Mitzi Nagarkatti and Alan Decho, from the university's School of Medicine and Arnold School of Public Health, respectively, also showed that the antimicrobial effectiveness of the four beta-lactams studied in detail was enhanced by the polymer. The enhancement was modest against two strains, but very pronounced with the hospital-associated strain of MRSA (HA-MRSA).

The metallopolymer by itself even demonstrated antimicrobial properties, lysing bacterial cells while leaving human red blood cells unaffected. By a variety of measures, the polymer was found to be nontoxic to human cells in laboratory tests.

The project is still far from clinical use, but Tang knows moving forward is imperative.

"In the United States every year, around 100,000 patients die of bacteria-induced infections," Tang said. "And the problem is increasing because bacteria are building resistance.

"It's a really, really big problem, not only for individual patients, but also for society."


Contact: Steven Powell
University of South Carolina

Related medicine news :

1. Penicillin equally effective as big gun antibiotics for treating less severe childhood pneumonia
2. Penicillin Prevents Return of Leg Infection Called Cellulitis: Study
3. Economic analysis finds penicillin, not "the pill," may have launched the sexual revolution
4. CONRAD wins USAID Science and Technology Pioneers Prize for development of first vaginal gel proven to reduce HIV
5. Study examines repeat colonoscopy in patients with polyps referred for surgery without biopsy-proven cancer
6. Discover 50 Yoga Exercises That Are Proven Good For Health – V-kool
7. VitaPro Labs Launches New Withdrawal Aid System at, a Supplement Proven To Ease Opioid Withdrawal Symptoms
8. Added benefit of saxagliptin as monotherapy is not proven
9. Phen375: The Clinically Proven Highly Effective Weight Loss Pills Now Available in the Market with 1 Month Extra Supply for Limited Time
10. Har Vokse: The Clinically Proven Highly Effective Hair Regrowth Treatment Product Now Offers 1 Month Extra Supply for Limited Time!
11. Revitol Eye Cream: The Clinically Proven Highly Effective Cream for Eye Dark Circles, Puffiness, Fine Lines and Wrinkles; Now Available with 1 Extra Jar Offer!
Post Your Comments:
Related Image:
Penicillin redux: Rearming proven warriors for the 21st century
(Date:11/28/2015)... ... November 28, 2015 , ... Pixel Film Studios is back again ... choose from, the possibilities are endless. Users have full control over angle of view, ... masking effects, users are sure to get heads to turn. , ProPanel: Pulse offers ...
(Date:11/27/2015)... ... November 27, 2015 , ... ... care in America. As people age, more care is needed, especially with Alzheimer’s, ... and medical professionals are being overworked. The forgotten part of this equation: 80 ...
(Date:11/27/2015)... ... November 27, 2015 , ... ... edition of USA Today in Atlanta, Dallas, New York, Minneapolis, South Florida, with ... digital component is distributed nationally, through a vast social media strategy and across ...
(Date:11/27/2015)... ... ... A simply groundbreaking television series, "Voices in America", which is hosted by ... of issues that are presently affecting Americans. Dedicated to providing the world with a ... the subjects consumers focus on, one episode at a time. , In the ...
(Date:11/27/2015)... CA (PRWEB) , ... November 27, 2015 , ... ... California Medical Associates, Inc. and Dr. Tucker Bierbaum with Emergency Medicine at ... They observed that both STEMI and Sepsis conditions present in similar ways and require ...
Breaking Medicine News(10 mins):
(Date:11/29/2015)... , Nov. 29, 2015 CIVCO ... guidance technology at the Radiological Society of ... Chicago November 29 – ... is designed to offer customers unrivaled versatility, enhanced ... --> ...
(Date:11/27/2015)... November 27, 2015 Ein ... fortgeschrittenem Krebs.   --> Ein neuer ... Krebs.   --> Ein neuer ... Krebs.   Clinical Cancer Research ... Clinical Cancer Research vom 6. November 2015 ...
(Date:11/26/2015)... , November 27, 2015 ... --> --> ... emergency response system (PERS) market ... for 5 years with APAC ... expected to see a high ...
Breaking Medicine Technology: