Thursday, May 12, 2011

Evidence-Based Strategies for the Containment of Antibiotic Resistance

Professor Sabiha Essack (B. Pharm., M. Pharm., PhD), Dean of the Faculty of Health Sciences and Professor in the School of Pharmacy and Pharmacology at the University of KwaZulu-Natal is a Welcome Trust Research Fellow who completed research towards her PhD in Pharmaceutical Microbiology at St Bartholomew’s and the Royal London School of Medicine and Dentistry in the United Kingdom. She is also the president of APUA-South Africa.

Antimicrobial resistance is currently the greatest challenge to the effective treatment of infections globally. Resistance adversely affects both clinical and financial therapeutic outcomes with effects ranging from the failure of an individual patient to respond to therapy and the need for expensive and/or toxic alternative drugs to the social costs of higher morbidity and mortality rates, longer durations of hospitalisation, increased health care costs and the need for changes in empirical therapy. Resistance may emerge by selection pressure (overuse/indiscriminate antimicrobial use in developed vs under-use/misuse in developing countries) but is perpetuated by diverse risk factors and maintained within environments as a result of poor infection control. Population-specific drug pharmacokinetics and pharmacodynamics also play a role. The WHO, US, UK and EU have initiated strategies for the containment of resistance, with surveillance critical to all.

Surveillance in South Africa should be disease-based, establishing sensitivity profiles of common causative organisms to inform the development of or amendment to standard treatment guidelines and essential drugs lists adopted within national drug policies in developing countries globally. The manner of antimicrobial use (overuse, underuse, inadequate dosing) associated with resistance must be established for appropriate intervention in terms of rational drug use, a reduction in use and dosing regimens based on population-specific pharmacokinetics and pharmacodynamics. Risk factors unique to South African communities (poverty, HIV) and hospitals (duration of hospitalisation, location within the hospital, intensive care unit stay, surgery, wounds, previous and current antimicrobial therapy, mechanical ventilation, urinary catherterisation, nasogastric intubation, central venous and peripheral catheters, previous hospitalisation and transfer from another unit or hospital) must be determined and due vigilance exercised in patients exhibiting classical risk factors for the acquisition of or colonisation with resistant pathogens.
Hygiene and sanitation (in communities) and infection control (in hospitals) status must be determined and interventions initiated to prevent the spread of resistance. Pharmacokinetics and pharmacodynamics specific to diverse populations must be devised to optimise antimicrobial therapy. Evidence-based treatment of infections guided by local susceptibility/resistance would ensure productive, economically viable individuals capable of fulfilling their social roles. Efficacious treatment would assure sustainable livelihoods in all populations (healthy and otherwise) as infections are the most frequently encountered health problem even in the absence of HIV/AIDS. While one infection will ultimately be fatal, the efficacious use of antibiotics will successfully treat several infections in the lifetime of the AIDS patient even in the presence of a compromised immune system sustaining the economic viability of the country and preventing the economic collapse portended by the World Bank. South Africa has unique needs in the antimicrobial resistance arena, needs to be addressed in the context of severe financial, human resources and technological challenges.