19/03/08

Reducing antibiotics not enough to stem resistance

Xray of lungs infected by pneumonia Copyright: CDC

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Reducing antibiotic use is not enough to curb the rise of resistance in the developing world, say Zulfiqar A. Bhutta and Syed Rehan Ali.

Ever since the advent of antibiotics, the phenomenon of increasing resistance to commonly used antibiotics has been well-recognised.

Excessive and uncontrolled use of antibiotics in humans and animals are major contributors to the spread of resistance. In a rapidly globalising world where people have easy access to long-distance travel, antibiotic-resistant organisms can easily cross continents and infect individuals.

Resistance can also be transferred between different disease-causing bacteria, with deadly consequences for health systems in both developed and developing countries. 

While the extent of resistance and its health and economic costs are well-documented in developed countries, relatively little is known about the burden and consequences of resistance in developing countries, where data are sparse and monitoring systems poor. Nevertheless, given that many developing countries have enormously high rates of infectious disease, the directly attributable economic costs of resistance must be considerable. Lack of access to effective treatment for resistant infections is an important additional contributor to morbidity.

Poverty and inequity

Poverty and inequity are major drivers of antimicrobial resistance. In developing countries they are linked to inadequate access to effective drugs, unregulated dispensing by unqualified staff and truncated therapy for reasons of cost.

In addition, substandard generics — and counterfeit medications — are burgeoning because of the cost of branded antibiotics. Poor people often buy them from uncontrolled street vendors and even then cannot afford to complete a full course of treatment.

This vicious cycle promotes the emergence of antimicrobial resistance and can make treatment less effective.

The widespread and frequently unnecessary use of antibiotics is also related to health system weaknesses, with poorly trained care providers and lack of suitable laboratory facilities frequently resulting in inappropriate treatment.

For example, because of limited capacity to obtain a bacteriological diagnosis of typhoid fever, treatment is often initiated with ineffective antibiotics and changed to second line therapy following clinical treatment failure. In other instances, physicians may choose to initiate treatment unnecessarily with second line antibiotics. Sometimes alternative antibiotics may not be available at all.

Extra costs

As a result of widespread resistance among common bacterial pathogens such as Streptococcus pneumoniae and Hemophilus influenzae that cause childhood pneumonia, it is no longer feasible to treat cases of moderate-to-severe pneumonia with first line antibiotics like co-trimoxazole. Although health systems are gearing to change to amoxicillin for the treatment of childhood pneumonia, this will take time and considerable resources.

Resistant bacteria are often more virulent, leading to more severe illness. Multidrug-resistant (MDR) typhoid, for example, is associated with greater clinical severity of illness and more complications than the non-resistant form of the disease.

One study showed that despite treatment with injectable ceftriaxone, the mean time before children with MDR typhoid lost their fever was 7.2 days, compared with 6.3 days for sensitive typhoid. The drug treatment costs for an episode of MDR typhoid fever, a common childhood infection, are considerably higher than for sensitive typhoid. So increasing antibiotic resistance is associated with higher economic burden on health systems from the combination of higher rates of complications and enhanced health care costs.

This extra economic burden can be considerable. Our findings from population-based studies on typhoid fever in urban Karachi indicate that the average cost of illness was more than US$50 per episode, most of which was out-of-pocket costs for antibiotics.

Pragmatic action

Rational drug use is a cornerstone for reducing inappropriate antimicrobial use and requires physician and patient education as well as industry collaboration. In addition, given widespread over-the-counter availability of antibiotics in many developing countries, regulation and oversight of antibiotic use are key interventions.

In addition, every effort needs to be made to “protect” newer and second line antibiotics from widespread use in health facilities or general practice. Merely reducing antibiotic use may be simplistic. But selective and appropriate use of antibiotics (with the correct dose and duration of therapy) may make a difference.

The challenge is to implement these strategies within health systems by engaging both the public and private sectors. This may require a series of measures including staff training, strengthening of health systems and rational prescribing, as well as regulation of antibiotic use and over-the-counter prescribing.

Zulfiqar A Bhutta is the professor and chairman, department of paediatrics & child health, and Syed Rehan Ali is an assistant professor, both at the Aga Khan University, Karachi, Pakistan.

This article is part of a Spotlight on Fighting antibiotic resistance.