It was important to be able to outpace virulent organisms, said Dr Magnus Gottfredsson (consultant in infectious diseases, University Hospital, Reykjavik). The implications of serious infections that were outwitting the pharmaceutical industry were high cost, high mortality and increased length of stay in hospital, he said.
It had been thought for a number of years that these emerging organisms had been generated within hospitals because of increased use of vancomycin in combination with third generation cephalosporins. There were now data to implicate the overuse of antibiotics in the food animal industry, he suggested.
Dr Gottfredsson described some of the newer agents that had promise for tackling these infections. Ziracin, an everninomicin, was still under investigation but studies had shown that it worked well against a number of hospital acquired resistant infections.
It was interesting though to look at the "flip-side", continued Dr Gottfredsson, as a related agent, avilamycin, had been used as a growth promoter in animals for years and there was now evidence that this had created a reservoir of organisms with decreased susceptibility to everinomicins. Dr Gottfredsson added that this pool of resistant organisms had been created even before this class of antibiotics had been developed for human use.
The streptogramins were another class of antibiotics that were useful for treating serious vancomycin-resistant enterococcal infections. The combination of quinupristin and dalfopristin (Synercid) was suitable for treating certain serious Gram-positive infections where no alternative was available, said Dr Gottfredsson. Synercid was not active against Enterococcus faecalis, possibly because a highly related streptogramin, virginiamycin, had been used as a growth promoter in the EU for decades.
The remaining options for treating resistant organisms were the ketolides, which were still in pre-clinical studies, and the oxazolidinones, said Dr Gottfredsson. Linezolid, the first oxazolidinone to be used clinically, looked promising and the results from clinical studies were now starting to be published, he said.
Other topics covered: |