Penicillin and Amoxicillin's days are numbered

By Wai Lang Chu

- Last updated on GMT

Related tags Bacteria Antibiotic resistance

The threat of antibiotic resistance reared its ugly head again
after US researchers found that the most common antibiotic
treatments do not work in a significant number of cases, leading
for calls to find viable alternatives to ageing, established,

Antibiotic resistance has become a problem in the pharmaceutical industry that no one wants to or knows how to deal with. This could be because the acceptance of a need for alternatives would essentially mean pharma has lost confidence of antibiotics such as penicillin and amoxicillin.

Researchers from the University of Rochester​ started with the analysis of data from 11,426 children who has suffered a common throat infection.

They found that 25 per cent of children given penicillin, along with 18 per cent given amoxicillin treatment needed further treatment within weeks.

The results were presented to the Interscience Conference on Antimicrobial Agents and Chemotherapy in Washington this week and serves to underlie the spread of antibiotic-resistant microorganisms that has featured strongly at this event.

The data, taken from 47 studies from the past 35 years looked at the effectiveness of various drugs on treating strep throat in children.

Additional results revealed that of those given older-generation cephalosporin antibiotics, 14 per cent had to return for more treatment, while just 7 per cent prescribed newer versions like cefpodoxime and cefdinir, given for just four or five days, had to go back to the doctor.

The news that newer versions of antibiotics fared slightly better in the study will come as a shock to most doctors, who were relieved to find additions to the waning arsenal of antibiotics.

The study suggested that other bacteria, which can be present in the throat, could hamper the effectiveness of the drugs. This happens because many bacteria produce enzymes called beta-lactamase that can inactivate penicillin and amoxicillin.

Strep does not - but it is possible the other bacteria, which do, are present in the throat and can inactivate a drug before it has a chance to work

"The treatment paradigm [model] for treating strep sore throats has been changing slowly, and endorsing the use of cephalosporins as a first-line treatment is something that needs to be seriously considered,"​ said Michael Pichichero, Professor of microbiology and immunology who led the research team.

Currently, The World Health Organisation recommends penicillin as the first line of treatment for strep throat and the Health Protection Agency guidance is in accordance with this.

While the newer short-course cephalosporins are only available in brand-name form and are much more expensive, older ones such as cephalexin (better known as Keflex) cost about the same as penicillin or amoxicillin but are more effective against strep.

Pharma's reply during 2005 saw the launch of the first in a new class of antibiotics, the glycylcyclines from Wyeth. The product, tigecycline (Tygacil) joins the oxazolidinones, (Pfizer's linezolid) and lipopeptides (Cubist's daptomycin) in a small but growing arsenal against drug-resistant bacterial infections.

Related topics Preclinical Research

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