Work at the Cambodia Oxford Medical Research Unit (COMRU) and Angkor Hospital for Children (AHC) has highlighted the importance of melioidosis, infection by the soil-dwelling bacterium Burkholderia pseudomallei, as a cause of severe illness in Cambodian children (P Turner et al and Pagnarith et al).
In October 2017, COMRU will participate in the 2nd Cambodia National Melioidosis workshop, a three day event to improve awareness of Burkholderia pseudomallei infection amongst Cambodian clinicians and laboratory technicians. COMRU’s Miliya Thyl and Soeng Sona will both give presentations at the meeting, alongside director Paul Turner.
To support the workshop’s laboratory sessions, COMRU commissioned a short film in English [above] and Khmer to demonstrate laboratory identification of B. pseudomallei. The video was shot at Angkor Hospital for Children and the microbiology laboratory of the Cambodia Oxford Medical Research Unit. We are very grateful to MORU’s Prof Phaikyeong Cheah and the Wellcome Trust for provision of public engagement funding to support the making of the film.
Cambodia Oxford Medical Research Unit (COMRU)
The Cambodia Oxford Medical Research Unit (COMRU) was established in 2007 as a collaboration between the Angkor Hospital for Children and MORU. The first step in this collaboration was to equip the Angkor Hospital with a microbiological laboratory, and to train the Hospital's technical staff. COMRU are now using this facility to prospectively define the causes of febrile illness and establish susceptibility patterns of common culturable bacterial pathogens. These data will also allow researchers to identify causes of sepsis and sepsis-related death, and will improve diagnosis, treatment and management of paediatric infections in Cambodia. The Mahidol Oxford Tropical Medicine Research Unit (MORU) develops effective and practical means of diagnosing and treating malaria and other neglected diseases such as melioidosis, typhus, TB and leptospirosis.
Mahidol Oxford Tropical Medicine Research Unit (MORU)
MORU was established in 1979 as a research collaboration between Mahidol University (Thailand), Oxford University (UK) and the UK’s Wellcome Trust. MORU’s main office and laboratories are located within the Faculty of Tropical Medicine at Mahidol University in Bangkok, Thailand, with MORU study sites and collaborations across Thailand, Asia and Africa. MORU is generously supported with significant funding from the Wellcome Trust, our major funding partner. We also receive funding from other trusts and foundations, governments, and multi-lateral donors.
Angkor Hospital for Children (AHC)
Renowned Japanese photographer Kenro Izu first visited Cambodia in 1993 to photograph the magnificent Angkor Temples. Cambodia was struggling to emerge from the brutal Khmer Rouge regime, and Kenro was deeply touched by the resilient children he met during his trip. Kenro realized he could not leave Cambodia without doing something for these impoverished children he had seen and captured from behind the lens. He founded a non-profit organization called Friends Without a Border (FWAB) and with the help of the international art community, health care professionals and more than 6,000 supporters from around the world, Angkor Hospital for Children opened its gates in 1999. Today, Claudia Turner is the CEO of the hospital and is an Oxford University Principal Investigator.
Paul Turner (COMRU Director)
Paul Turner is a clinical microbiologist based at the Angkor Hospital for Children in Siem Reap, Cambodia. He is director of the Cambodia-Oxford Medical Research Unit (COMRU).
His research interests include:
- Antimicrobial resistance surveillance and control;
- Paediatric healthcare associated infections;
- Pneumococcal colonisation and disease and the impact of pneumococcal vaccines.
The purpose of this short film is to describe and demonstrate identification of Burkholderia pseudomallei using the Mahidol University latex agglutination test. B. pseudomallei is the cause of melioidosis, an important but under recognized infection in many tropical countries. There is a high incidence of human melioidosis in northern Australia, Thailand and other Southeast Asian countries.
B. pseudomallei is a soil-dwelling bacterium. Human infection occurs after direct inoculation, inhalation or ingestion of the organism. At Angkor Hospital for Children, melioidosis was first recognized as an important cause of severe infection in Cambodian children in 2005. The laboratory now confirms around 30 to 50 cases of melioidosis each year
Burkholderia pseudomallei is a human pathogen and requires appropriate laboratory containment Laboratory staff should wear appropriate personal protective equipment: laboratory coat, gloves and safety glasses. All laboratory work should be performed in a well-maintained and certified biosafety cabinet.
Burkholderia pseudomallei is a motile, oxidase positive gram-negative bacillus. B. pseudomallei colonies are usually cream-colored with a metallic sheen, and may become dry and wrinkled after more than 24 hours incubation on blood agar, although considerable variation is seen. On MacConkey agar, B. pseudomallei colonies will be white and opaque with a metallic sheen after overnight culture, and then become pink and rugose after 48 hours. Culture on Ashdown medium, selected medium for B. pseudomallei results in pink purple colonies which become large and wrinkled by 3 to 4 days. In endemic areas it is important to consider the possibility of B. pseudomallei in all oxidase positive gram-negative bacilli.
The Mahidol University latex agglutination test uses latex particles coated with monoclonal antibodies specific for the 200 kilodalton exopolysaccharide of B. pseudomallei. The test enables rapid screening of suspected colonies, and has been found to have 95 to 99 percent sensitivity and 99 to 100 percent specificity. However it does not reliably distinguish B. pseudomallei from B. mallei.
The kit has a long shelf life. It must be stored in a refrigerator at two to eight degrees centigrade. Before use, the kit should be removed from the refrigerator, allowed to warm up to room temperature and mixed thoroughly. The kit contains latex reagent, a positive control and a negative control. The positive control is a suspension of killed B. pseudomallei in phosphate buffered saline. The negative control is a suspension of killed B. thailandensis in phosphate buffered saline. Control should be run once a day to verify that the kit is performing correctly. Also required but not included in the kits are glass slides, a micro pipette and tips and microbiological loops or toothpicks.
First, pipette 10 microliters of latex reagent onto a fresh glass slide. Identify a well isolated colony and pick using a toothpick or loop. Mix the colony into the latex reagent. Rotate the slide for up to two minutes and watch for a positive reaction to occur. A positive reaction is indicated by fine agglutination with clearing of the background. Latex positive colonies may be further confirmed by demonstration of resistance to colistin and gentamicin, but susceptibility to co-amoxiclav. A triple sugar iron slope should be nonreactive with no gas or hydrogen sulfide. Biochemical identity may be confirmed by the biome area API 20E/NE test strip, or other commercial identification systems, although occasional misidentification may occur.
All contaminated lab consumables should be decontaminated and disposed of following local and national policies. Once all laboratory procedures have been completed, culture plate should be autoclaved prior to disposal