Identification of Streptococcus sinensis from a patient with endocarditis using MALDI-TOF mass spectrometry, 16S rDNA- and sodA-based phylogeny

El-klila, Jben, Rayeb and Lben are artisanal dairy products typical of the North African region. These products are considered a good source of nutrients and a vector par excellence of indigenous lactic acid bacteria with significant technological and therapeutic potential. In this study, fifty-two Lactobacillus isolates from traditional dairy products (El-Klila, Jben and Rayeb) from the Ain Sefra region (southwestern of Algeria) were identified by phenotypic, genotypic and MALDI-TOF mass spectrometry methods. Phenotypic characterization allowed dividing the isolates into two groups: 7.69% of isolates mesophilic and strict heterofermentative and 92.31% isolates mesophilic and optional heterofermentative. The isolates identification by sequencing 16S rDNA was performed using the universal primers w02 and w18. Comparing the sequences of the isolates with the GenBank database (NCBI) revealed a high percentage with five species of Lactobacillus. Of the 52 isolates, thirteen were identified as Lactobacillus paracasei, four isolates were L. brevis, five isolates were L. rhamnosus and ten isolates were L. plantarum. The lasting twenty isolates were related, at the same time, to the plantarum species and the pentosus species. The use of MALDI-TOF mass spectrometry confirmed the identity of 36 strains of Lactobacillus. Of the 20 isolates related to the plantarum / pentosus group by 16S rDNA, 50% were identified as L. plantarum. Finally, the results of the two combined methods allowed us to correctly identify 80.76% of the Lactobacillus isolates at the genus and species level. The analysis by MALDI-TOF SM has proved to be a very reliable, fast (less than an hour) and inexpensive tool for identifying native Lactobacillus species from artisanal dairy products. This method can constitute a major tool for the study of the microbial biodiversity of artisanal food products.

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Francisella philomiragia bacteremia in an immunocompromised patient: a rare case report

Annals of Clinical Microbiology and Antimicrobials ◽

10.1186/s12941-021-00475-2 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Hui Shan Chua ◽

Yih Harng Soh ◽

Shih Keng Loong ◽

Sazaly AbuBakar

Keyword(s):

Mass Spectrometry ◽

16S Rdna ◽

Acute Pulmonary Oedema ◽

Molecular Technique ◽

Type I ◽

16S Rdna Sequencing ◽

Maldi Tof Mass Spectrometry ◽

Prompt Treatment ◽

Maldi Tof ◽

Rdna Sequencing

Abstract Background Francisella philomiragia is a very rare opportunistic pathogen of humans which causes protean diseases such as pneumonia and other systemic infections. Subsequent failure of prompt treatment may result in poor prognosis with mortality among infected patients. Case presentation The present report describes a case of F. philomiragia bacteraemia first reported in Malaysia and Asian in a 60-year-old patient with underlying end-stage renal disease (ESRF) and diabetes mellitus. He presented with Acute Pulmonary Oedema with Non-ST-Elevation Myocardial Infarction (NSTEMI) in our hospital. He was intubated in view of persistent type I respiratory failure and persistent desaturation despite post haemodialysis. Blood investigation indicated the presence of ongoing infection and inflammation. The aerobic blood culture growth of F. philomiragia was identified using the matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (Score value: 2.16) and confirmed by 16S Ribosomal DNA (16S rDNA) sequencing. He was discharged well on day 26 of admission, after completing one week of piperacillin/tazobactam and two weeks of doxycycline. Conclusion Clinical suspicion should be raised if patients with known risk factors are presenting with pneumonia or pulmonary nodules especially as these are the most common manifestations of F. philomiragia infection. Early diagnosis via accurate laboratory identification of the organism through MALDI-TOF mass spectrometry and molecular technique such as 16S rDNA sequencing are vital for prompt treatment that results in better outcomes for the afflicted patients.

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