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This article discusses a rare case of meningitis caused by Moraxella osloensis, a bacterium that is difficult to identify due to its similarities to other species. The patient initially presented with symptoms of headache, fever, and cranial nerve injury, leading to a diagnosis of viral meningitis. However, antiviral therapy did not improve the patient's condition, and conventional diagnostic methods were inconclusive. The use of metagenomic next-generation sequencing (mNGS) allowed for the accurate identification of the pathogen and guided appropriate antibiotic treatment. The patient ultimately recovered. The article emphasizes the importance of mNGS in cases where traditional diagnostic methods are ineffective and highlights the need for further research on susceptible groups for M. osloensis infection. [Extracted from the article]

Moraxella osloensis, a gram-negative rod-shaped bacterium found on human skin, produces 4-methyl-3-hexenoic acid, contributing to clothing and body malodor. M. osloensis is resistant to UV light, drying, and antimicrobials, making its eradication challenging. As the skin is low in nutrients, commensal bacteria compete for resources and use diverse strategies to inhibit their competitors. Therefore, skin-derived bacteria that exhibited growth-inhibitory activity against M. osloensis were searched. Screening skin-derived bacteria using a coculture halo assay revealed that Bacillus xiamenensis formed an inhibition zone with M. osloensis. Coculture plates were extracted with ethyl acetate and fractionated using a silica gel column and preparative thin-layer chromatography to isolate the active compound from the B. xiamenensis metabolites. Nuclear magnetic resonance spectroscopy identified the active compound as indole-3-carboxaldehyde, which has low toxicity in humans. At soluble concentrations, indole-3-carboxaldehyde does not inhibit the growth of other bacteria, such as Staphylococcus aureus, Escherichia coli, and Bacillus subtilis, suggesting M. osloensis is highly sensitive to indole-3-carboxaldehyde. These findings highlight B. xiamenensis as a promising candidate for the development of a skin probiotic to promote skin health and combat malodor-causing bacteria., (© 2024 The Author(s). MicrobiologyOpen published by John Wiley & Sons Ltd.)

ABSTRACT In our daily lives we are confronted with various kinds of malodour problems. Detailed analysis at the molecular level of the malodorous constituents with gas chromatography-mass spectrometry and gas chromatography-olfactometry can be used to identify the key chemicals responsible for the malodours, and such information can provide novel starting points for the development of new deodorants. This paper describes two characteristic sources of malodour in daily life: axillary and laundry malodour. Detailed analytical studies identified specific major contributors to these malodours: 3-hydroxy-3-methylhexanoic acid, 3-mercapto-3-methylhexan-1-ol and 4-methyl-3-hexenoic acid. Biochemical and microbiological studies then elucidated the mechanisms generating these odours and proved the involvement of microbes in odour formation. In this review, we discuss the importance of the branched C7 chain, which is common to all the major volatile substances identified in these studies and perceived by the human nose with an extraordinary sensitivity. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]