'Arthrobacter saudimassiliensis' sp. nov. a new bacterial species isolated from air samples in the urban environment of Makkah, Saudi Arabia.

We report here the main characteristics of 'Arthrobacter saudimassiliensis' strain 11W110_airT (CSUR P1223), a new species of the Arthrobacter genus that was isolated from air samples in the city environment of Makkah, Saudi Arabia, during the pilgrim period of Hajj 2012.

As a part of a wider culturomics and metagenomics study [1], [2] in Saudi Arabia we isolated a new bacterium named strain 11W110_airT from two air samples in the urban environment of Makkah, Saudi Arabia, during the pilgrim period of Hajj 2012. No identification was obtained for strain 11W110_airT using systematic matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) screening on a MicroFlex spectrometer (Bruker Daltonics, Bremen, Germany) [3]. The strain 11W110_airT was cultured in 5% sheep blood-enriched Columbia agar (bioMérieux, Marcy l'Étoile, France) for 1 day in an aerobic atmosphere at 37°C. Growth was observed only in aerobic conditions and no growth occurred in anaerobic conditions. Colonies on Columbia agar were opaque, round and yellow. Optimal growth for this strain was obtained at 37°C at pH 7. The strain 11W110_airT is a Gram-positive bacterium, aerobic, motile, catalase positive and oxidase negative.

The complete 16S rRNA gene was sequenced using fD1-rP2 primers as previously described and a 3130-XL sequencer (Applied Biosciences, Saint Aubin, France) [4]. The strain 11W110_airT exhibited a 97.4% sequence similarity with Arthrobacter luteolus (NR025362), which was the phylogenetically closest species with standing nomenclature (Fig. 1). Consequently, it putatively classifies the strain 11W110_airT as a new member of the genus Arthrobacter within the family Micrococcaceae in the phylum Actinobacteria. Arthrobacter luteolus was first described by Wauters et al. in 2000 as an aerobic, Gram-positive coryneform bacteria isolated from an infected surgical wound [5]. So far, the genus Arthrobacter includes more than 87 species with validly published names (http://www.bacterio.cict.fr/c/arthrobacter.html).

Fig. 1

Phylogenetic tree highlighting the position of ‘Arthrobacter saudimassiliensis’ relative to the phylogenetically closest members of the Arthrobacter genus. Numbers at the nodes are percentages of bootstrap values obtained by repeating the analysis 500 times to generate a majority consensus tree. Only values >95% are displayed. The scale bar represents a 0.5% nucleotide sequence divergence.

Strain 11W110_airT exhibited a 16S rRNA gene sequence divergence >1.3% with A. luteolus, the closest related species with standing in nomenclature, which classifies it as a new representative of the Arthrobacter genus isolated from air samples in the urban environment of Makkah. As a result, we propose the creation of ‘Arthrobacter saudimassiliensis’ sp. nov., and the strain 11W110_airT as the type strain.

MALDI-TOF MS spectrum accession number. The MALDI-TOF MS spectrum of ‘Arthrobacter saudimassiliensis’ 11W110_airT is available online (http://www.mediterranee-infection.com/article.php?laref=256&titre=urms-database).

Nucleotide sequence accession number. The 16S rRNA gene sequence of the strain 11W110_airT was deposited in GenBank under Accession number HG931344.

Deposit in a culture collection. Strain 11W110_airT was deposited in the Collection de Souches de l’Unité des Rickettsies (CSUR, WDCM 875) under number P1223.

Transparency declaration

The authors have stated that there are no conflicts of interest.