Cephaloticoccus gen. nov., a new genus of 'Verrucomicrobia' containing two novel species isolated from Cephalotes ant guts

Two novel members of the bacterial phylum 'Verrucomicrobia', strains CAG34(T) and CV41(T), were isolated from the guts of Cephalotes rohweri and Cephalotes varians ants, respectively. Strains CAG34(T) and CV41(T) were coccoid, Gram-stain-negative, non-motile, and formed cream-coloured colonies on trypticase soy agar. Optimum growth occurred under an atmosphere of 12-20% O-2 and 1% CO2 for both strains, although strain CV41(T) could not grow without supplemental CO2. Growth was possible under NaCl concentrations of 0.5-1.5% (w/v) and temperatures of 23-37 degrees C for both strains, and pH values of 6.9-7.7 for strain CAG34(T) and 6.9-7.3 for strain CV41(T). The G+C content of the genomic DNA was 60.7 mol% for strain CAG34(T) and 60.5 mol% for strain CV41(T). The major fatty acids for both strains were anteiso-C-15 : 0, iso-C-14 : 0, C-16 : 0, and C-16 : 1 omega 5c. Based on the phylogenetic analysis of 16S rRNA gene sequences, the closest cultivated relative for both strains was the type strain of Opitutus terrae (91.8% similarity). Hence, strains CAG34(T) and CV41(T) are considered to represent a new genus within the 'Verrucomicrobia' family Opitutaceae, for which we propose the name Cephaloticoccus gen. nov. Given that strains CAG34(T) and CV41(T) share 97.7% 16S rRNA gene sequence similarity with each other and are physiologically distinct, we propose to classify the isolates as representing two novel species, Cephaloticoccus primus sp. nov. for strain CAG34(T) (=NCIMB 15004(T) =ATCC TSD-38(T)) and Cephaloticoccus capnophilus sp. nov. for strain CV41(T) (=NCIMB 15005(T) =ATCC TSD-39(T) =DSM 100879(T)).