Medan — A 2026 study published in the International Journal of Scientific Multidisciplinary Research reports that non-toxigenic strains of Corynebacterium diphtheriae can cause clinically significant infections in children, even without producing the classic diphtheria toxin. The research was conducted by Darmawali Handoko and colleagues from the National Health Biology Laboratory and the Surveillance Unit of the North Sumatra Provincial Health Office, highlighting a growing public health concern that may be underdiagnosed.
Diphtheria is widely recognized as a vaccine-preventable disease typically associated with toxin-producing bacteria that affect the upper respiratory tract. However, this new evidence shows that non-toxigenic variants—previously considered less dangerous—can still invade the body and cause infections in unexpected ways. The findings are particularly relevant for regions with active surveillance systems, as they challenge conventional diagnostic assumptions.
Globally, similar cases have been reported in Europe and the United States, where non-toxigenic Corynebacterium diphtheriae has been linked to bloodstream infections, endocarditis, and wound infections. Despite high vaccination coverage in many countries, these cases demonstrate that immunity against the toxin does not fully eliminate the risk of infection. In Southeast Asia, especially among children, such data remain limited, making this study from North Sumatra a critical contribution to regional epidemiology.
The research team examined two pediatric cases identified through laboratory surveillance. The first case involved a five-year-old child whose blood culture tested positive for C. diphtheriae biovar gravis. Notably, the child did not present classic respiratory symptoms such as pseudomembrane formation in the throat. The second case involved a 13-year-old child with a wound infection, where laboratory analysis also detected the same bacterial species.
To confirm the diagnosis, researchers conducted a series of laboratory tests, including biochemical identification, microscopic examination, and molecular testing using polymerase chain reaction (PCR) to detect the presence of the diphtheria toxin gene. The Elek test, a standard method for determining toxin production, was also performed. Results from both cases confirmed that the bacterial isolates were non-toxigenic, meaning they did not produce the diphtheria toxin.
Key findings from the study include:
- The bacterium was detected in the bloodstream of a child without classic diphtheria symptoms, indicating invasive infection.
- A second case showed localized wound infection caused by the same species.
- Both bacterial isolates lacked toxin production but still caused clinically observable illness.
- Laboratory testing was essential for accurate diagnosis, as clinical symptoms alone were insufficient.
Darmawali Handoko from the National Health Biology Laboratory emphasized that these findings expand the known clinical spectrum of diphtheria-related infections. According to Handoko and his team, reliance on classical symptoms may lead to missed or delayed diagnoses, especially in cases involving non-toxigenic strains.
The study underscores the importance of strengthening laboratory-based surveillance systems. Without proper diagnostic tools, infections caused by non-toxigenic C. diphtheriae may go undetected, potentially contributing to silent transmission within communities. This is particularly concerning in regions where infectious disease monitoring relies heavily on symptom-based reporting.
From a public health perspective, the implications are substantial. Health systems may need to update diagnostic protocols to include testing for non-toxigenic strains. Training for healthcare professionals should also be expanded to improve recognition of atypical infection patterns. In addition, policymakers may consider integrating these findings into broader infectious disease control strategies.
The research also opens new directions for scientific inquiry. It challenges the long-standing assumption that toxin production is the sole determinant of C. diphtheriae pathogenicity. Emerging evidence suggests that other virulence factors may play a role in enabling the bacterium to invade host tissues and evade immune responses.
Handoko and his colleagues note that larger-scale studies are needed to better understand transmission dynamics, risk factors, and clinical outcomes associated with non-toxigenic infections. They also call for stronger collaboration between laboratories, hospitals, and public health institutions to improve early detection and response.
In practical terms, the study highlights the need for a more comprehensive approach to infectious disease management. While vaccination remains essential for preventing toxin-mediated illness, it does not fully address the risks posed by non-toxigenic strains. Integrating laboratory diagnostics with clinical assessment can help bridge this gap and improve patient outcomes.
0 Komentar