Highly Virulent Pathogens - a Post Antibiotic Era?

Abstract

The spectrum of infectious diseases is changing rapidly. Emerging infectious agents present an intriguing constellation of nosocomial challenges. Antimicrobial resistance results in increased morbidity, mortality and costs of health care. Resistance to antimicrobial agents has been recorded since 1940 with penicillin resistant Escherichia coli (E coli) (Abraham and Chain 1940).

A similar pencillin resistance was reported in 1944 in Staphylococus aureus (S. aureus) (Kirby 1944) Even before the widespread global use of penicillin, resistance had already been detected in both grampositive and gram-negative organisms. The 1990s herald the era of multiple drug resistance. To grasp further the enormity and complexity of our modern antimicrobial resistance problem, one only needs to think about how many - how fast -and in how many settings (hospitals, clinics, outpatients nursing and long term facilities, etc), these pathogens have developed antimicrobial resistance: Multiple drug-resistant Mycobacterium tuberculosis, penicillin-resistant Streptococcus pneumonia, fluconzole-resistant Candida, methicillin-resistant S. aureus (MRSA), vancomycin-resistant Enterococci (VRE) and now S. aureus with reduced susceptibility to vancomycin.

Given the dramatic increase in the incidence of multiple drug-resistant organisms - and now - the mounting evidence of resistance transfer from one organism to another, we will certainly witness a combined growth of nosocomial pathogens, for which there are no antibiotic solutions. Appropriate infection control measures for such resistant strains depend, in part, on the mechanisms of genetic information exchanged among micro-organisms. Clearly we need to strengthen the basic tenets of infection prevention and control; hygiene, engineering and microbial barriers, to prevent transinfection. We need to control horizontal nosocomial transmission of organisms. Contaminated environmental surfaces are a reservoir for resistant organisms such as MRSA (Boyce et al 1997) and VRE (Karanfil et al 1992).

Stringent infection control policies need to be developed and implemented. A comprehensively applied infection control programme will reduce the dissemination of resistant strains. Each patient care setting must examine its current practices and review the outcome efficacy. A consensus development conference to develop centres for disease control (CDC) formal guidelines against vancomycin intermediate-level resistant staphylococcus aureus (VISA) and vancomycin-resistant staphylococcus aureus (VRSA) may take a year or more to convene. This paper will examine the basic considerations currently offered by the CDC which may be valuable starting points for the enhancement of current infection control practices. Perspectives of the Society for Healthcare Epidemiology of America (SHEA) will also be included.