Normoglycaemic 18
Bacterial DNA was isolated from the collected saliva samples using the QIAamp Mini Kit (Qiagen, Hilden, North Rhine-Westphalia, Germany), according to the instructions of the manufacturer. PCR products was mixed in equidensity ratios. Then, mixture PCR products was purified with Qiagen Gel Extraction Kit (Qiagen, Germany). The libraries generated with NEBNext UltraTM DNA Library Prep Kit for Illumina and quantified via Qubit and Q-PCR and were analysed by Illumina MiSeq platform.