First Laos bacteraemia study highlights need for local knowledge

For the first time, researchers in Laos have published a study on the causes of bacteraemia, or blood infections caused by invasive bacteria, in the local population. The study, published in the American Journal of Hygiene and Tropical Medicine, has major healthcare implications for Laos, one of the world's poorest nations.

Laos has a population of 5.2 million, the majority of whom are rural rice farmers, and life expectancy in the country is 54 years. Prior to the study, which was funded by the UK's Wellcome Trust, little was known about the causes and distribution of bacterial disease in the country, which is a major killer of children and adults. The research involved a major collaboration between scientists from Laos, the UK, Thailand and Vietnam.

"This is the first description of the causes of bacteraemia in Laos, and Lao colleagues expect that it will have an important impact on health policy," says Dr Paul Newton, a University of Oxford researcher based at Mahosot Hospital, Vientiane, Laos. "It will influence what the Ministry of Health and international organisations recommend as therapy and how individual doctors treat patients with these conditions.

"Before this information was available, Lao doctors had to extrapolate from the evidence from Vietnam, Thailand and elsewhere. Not surprisingly, the Lao data suggests that this may not be appropriate and that local knowledge is crucial. This is particularly significant in a country whose health care system is under-resourced. In Laos, there is a great need for clinical research to develop the most locally appropriate, least expensive, but effective public health interventions. The Government of the Laos is actively encouraging such research."

The most common cause of bacteraemia found in children and adults alike was Salmonella enterica serovar typhi, the cause of typhoid fever. In fact, almost half of all children (44%) with community-acquired bacteraemia were found to have typhoid.

Unlike elsewhere in south-east Asia, the researchers found few cases of multi-drug resistant typhoid. Use of fluoroquinolone antibiotics in other countries is thought to have led to bacteria, such as those causing typhoid, to become less sensitive to treatment by first line drugs.

"The relative susceptibility of typhoid bacteria to antibiotics found in our study suggests that short courses of fluoroquinolone antibiotics can safely be used, which is different from the current situation in Vietnam where typhoid is usually resistant to commonly used, inexpensive antibiotics," says Dr Rattanaphone Phetsouvanh of the Mahosot Hospital.

However, there is no place for complacency, warns Professor Chanpheng Thammavong, Director of Mahosot Hospital,

"Public health measures to reduce the incidence of typhoid, such as improved sanitation and vaccination, may have a significant impact on morbidity and mortality in Laos, as it appears to have done in Thailand. However, vaccination is relatively expensive in Laos and may not be affordable. With improved trans-border communications between Laos and its neighbours, there is a real risk that the prevalence of multi-drug resistant typhoid may increase in Laos."

Amongst infants, the most significant cause of bacteraemia was Staphylococcus aureus, which can also cause pneumonia and skin infections. Over two-thirds of infants with clinically-significant bacteria in their blood were found to have the S. aureus infection.

"Our research found that S. aureus bacteraemia has a very high mortality rate amongst infants in Laos, killing one in four infected children," explains Dr Newton. "This means that we should seriously consider giving infants, especially newborn babies, anti-staphylococcal antibiotics, which can treat the infection."