sepsis Alert

some of us might have come across the phrase “ real-time PCR testing ”, which is a method used to diagnose SARS-CoV-2 infection .

The usual testing procedure will involve doctors or nurses taking a swab of a person ’ s nasopharynx . If the person is infected , SARS-CoV-2 viruses will be present on these swabs , but they cannot be seen by the naked eye .

Back in the laboratory , chemicals are added to the swabs to lyse the viruses and release their genetic material . In the case of the SARS-CoV-2 virus , the genetic material is ribonucleic acid ( RNA ). The amount of viral genetic material will subsequently be amplified using the polymerase chain reaction ( PCR ) technique , so that sufficient copies of it can be detected to confirm infection .

Viral infections can also be determined via detection of antibodies which are specific towards the infecting viruses . These antibodies can be detected in patients ’ blood and their other body fluids .

Not all infections are diagnosed using “ real time PCR ” or detection of antibodies . In the case of bacterial infections , doctors might request that samples of suspected infected sites be taken . These samples might come from various anatomical sites of our bodies , including wounds , blood , pus , surgical tissues , stools , urine , nasal secretions and so on .

Again , like viruses , bacteria cannot be seen by the naked eye . Therefore , in the laboratory , to confirm bacteria existence and the presence of infection , these samples will then be inoculated onto spherical plastic plates containing medium ( usually in the form of agar ) for bacteria growth .

This medium contains nutrients which will support bacteria growth . Due to the supplied nutrients and in the absence of interruption from the immune system , usually massive amounts of bacteria are able to grow on these agar plates ( photo ), making bacteria colonies visible to the eye .

These bacteria colonies are subjected to further biochemical testing to confirm the bacteria ’ s identity . The bacteria colonies are also tested for their susceptibility towards antibiotics . Antibiotics which inhibit the growth of these bacteria can then be administered to the corresponding patient to eliminate infection . Nevertheless , cultivation of bacteria in the laboratory usually takes more than a day . This will delay diagnosis in cases of life-threatening infections , which can lead to sepsis .

Sepsis is the body ’ s overwhelming immune response towards infection . We can try to identify sepsis via some

By Assoc Prof Dr Tan Toh Leong

and Assoc Prof Dr Neoh Hui-min

physical signs of the patient , such as slurred speech , discoloured or mottled skin and extreme shivering .

However , sometimes the signs projected by some individuals might not be clear . To confirm sepsis , usually blood from patients are drawn and inoculated onto agar plates ( as described above ) to check for bacterial growth . The time needed for bacterial growth ( and hence diagnosis ) will cost precious time in saving the patient ’ s life .

Therefore , some other alternatives for sepsis diagnosis are now being investigated , so that it can be diagnosed and treated rapidly . One method is via measurement of proteins and molecules secreted by the patient . These proteins or molecules ( termed as “ biomarkers ”) are often involved in the immune response or inflammatory pathways which cause sepsis and their levels are either elevated or lowered compared to healthy individuals . The measurement process usually

takes a shorter duration compared to the time required for bacterial culture . One drawback is that the equipment used to measure biomarkers are often expensive , bulky and only available at hospitals .

Miniaturization of these equipment to be portable , hand-held devices will be an interesting venture to enable sepsis diagnosis , even though patients are away from the hospital . This will allow early admission of patients into hospitals for lifesaving treatment and reduce the mortality from sepsis . — The Health

Associate Professor Dr Tan Toh Leong is Consultant Emergency Physician , Faculty of Medicine , Universiti Kebangsaan Malaysia ( UKM ), Founder and President of Malaysian Sepsis Alliance ( MySepsis ) while Associate Professor Dr Neoh Hui-min is Senior Research Fellow , UKM Medical Molecular Biology Institute ( UMBI ), UKM , and Secretary of MySepsis .