Stillbirth with a false-positive lung float test result - an unusual case report

Area of Science:

• Forensic pathology
• Microbiology
• Neonatal death investigation

Background:

• Determining live birth is critical in forensic investigations of infant deaths.
• The lung float test is a common method, but can be confounded by gas-producing bacteria.
• Previous cases of bacterial contamination mimicking live birth have been reported.

Purpose of the Study:

• To investigate a case of a newborn found lifeless where initial tests suggested live birth.
• To identify the etiological agent responsible for misleading forensic test results.
• To highlight the importance of microbiological examination in forensic casework.

Main Methods:

• Autopsy and histological examination of lung and gastrointestinal tissues.
• Performance of the lung float test and gastrointestinal tract float test.
• Microbiological culture and identification of microorganisms from lung tissue and heart blood.

Main Results:

• The lung and gastrointestinal tract float tests yielded positive results, initially indicating live birth.
• Microbiological examination identified Fusobacterium gonidiaformans in lung tissue and heart blood.
• Fusobacterium gonidiaformans, an obligate anaerobic gas-forming bacterium, was determined to be the cause of the false-positive float test results.

Conclusions:

• The presence of Fusobacterium gonidiaformans can lead to false-positive lung float test results, mimicking live birth.
• Microbiological analysis is essential to confirm or refute the findings of the lung float test in forensic investigations.
• This case underscores the need for comprehensive testing in determining the viability of a newborn at the time of death.