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Capsular Serotyping of Streptococcus pneumoniae by Latex Agglutination
Published on: September 25, 2014
Latex agglutination for bacterial antigens and meningococcus PCR: two useful tools in legal sudden deaths
A Fernández-Rodríguez1, J A Vázquez, M P Suárez-Mier
1Instituto Nacional de Toxicología y Ciencias Forenses, 28002 Madrid, Spain. a.fernandez@mju.es
Abstract:
Bacterial infections are considered to be a major cause of sudden deaths. The recognition of infections caused by Neisseria meningitidis is an essential duty of medicolegal offices due to the risk of secondary cases. Since other microorganisms, such as Haemophilus influenzae and Streptococcus pneumoniae, are also involved in infectious sudden deaths, the identification of the pathogen responsible for death is essential in order to establish a positive diagnosis while also preventing secondary meningococcal cases. However, because of the unreliability of culture methods used for autopsy specimens and the fragile nature of the microorganisms, other techniques were used. In this study, the detection of specific antigens of N. meningitidis (serogroups A, B, C, Y and W135), H. influenzae type b, S. pneumoniae and Group B Streptococcus was undertaken in 40 samples from sudden death cases in legal procedures with a latex agglutination test. In addition, a meningococcus polymerase chain reaction (PCR) assay (ctrA, crgA and siaD genes) was also used as a corroboration method for positive N. meningitidis agglutinations. Eleven cases of sudden death were confirmed to be due to meningococcus while one case was confirmed to have been caused by H. influenzae type b fulminant epiglottitis. Rapid laboratory diagnosis of meningococcal infection allowed contacts management and notification to the health authorities. From the point of view of the authors, forensic diagnosis of unascertained deaths should include latex agglutination and meningococcus PCR when a fulminant infection by N. meningitidis or H. influenzae is suspected as well as in deaths where the cause is unclear.
Insights
Sudden bacterial infections, particularly meningococcus, can cause death. This study used latex agglutination and PCR to identify pathogens in 40 cases, confirming 11 meningococcal and 1 Haemophilus influenzae type b deaths.
Area of Science:
- Forensic pathology
- Microbiology
- Public health
Background:
- Bacterial infections are a significant cause of sudden, unexplained deaths.
- Accurate pathogen identification is crucial for diagnosis and preventing secondary infections, especially with Neisseria meningitidis.
Purpose of the Study:
- To evaluate the efficacy of latex agglutination and PCR in identifying bacterial pathogens in sudden death cases.
- To determine the prevalence of Neisseria meningitidis and Haemophilus influenzae type b in medicolegal autopsies.
Main Methods:
- Analysis of 40 sudden death samples using latex agglutination for N. meningitidis, H. influenzae type b, S. pneumoniae, and Group B Streptococcus.
- Confirmation of N. meningitidis with a specific polymerase chain reaction (PCR) assay targeting ctrA, crgA, and siaD genes.
Main Results:
- Eleven cases were confirmed as meningococcal infections.
- One case was identified as Haemophilus influenzae type b fulminant epiglottitis.
- Latex agglutination and PCR proved effective in diagnosing bacterial meningitis and epiglottitis in post-mortem samples.
Conclusions:
- Forensic diagnosis of sudden deaths should incorporate latex agglutination and meningococcus PCR when fulminant infections are suspected.
- Rapid laboratory identification aids in public health interventions, including contact management and notification.
- These methods are vital for unascertained deaths potentially caused by bacterial infections.
