Molecular Identification of Staphylococcus aureus Isolated from Hospital and Community-Acquired in Baqubah City

Abstract

A total of 250 clinical specimens were obtained from several sources included vagina, urine, nose wounds and burns. The specimens were obtained in Baaquba Teaching Hospital in Diyala province during the period from October 2021 to February 2022. The prevalence of Staphylococcus aureus isolated from these sources which that were diagnosed by selective media, biochemical tests, and confirmed by VITEK 2 system. Results showed 44 (17.6%) positive growth for S. aureus which were distributed as 2 (4%) from urine, 5 (10%) from vagina, 12 (24%) from nose, 13 (26%) from wounds and 12 (24%) from burns. Anti-bacterial susceptibility tests showed that Ceftaroline was the most resisted antibiotic by 100% followed by Imipenem which was 93.2% Netilmicin was the most effective antibiotic with sensitivity of 81.8% followed by chloramphenicol which was sensitive in 65.9% of isolates. The resistance of the other antibiotics was 38.6% for Amikacin, 43.2% for Gentamicin, 45.5% for Tetracycline, 56.8% for Clindamycin, 59.1% for Clarithromycin, 38.6% for Ofloxacin, 43.2% for Ciprofloxacin and 88.6% for Nitrofurantoin.  For the production of beta lactamase enzymes, only 3 (6.8%) isolates had the ability to produce Extended Spectrum Beta Lactamase, and 1 (2.2%) were positive for Metallo Beta Lactamase. Genetic detection results showed 19 of 24 isolates were positive for mecA gene while 21 of 24 isolates were positive for coa gene. Sequencing results for coa gene showed that after executing NCBI BLASTn on these PCR amplicons, the sequencing reactions confirmed their exact identification. In terms of the 812 bp amplicons, the NCBI BLASTn software showed up to 97% to 99% matches in nucleotides between the analyzed specimens and S. aureus target sequence references. By correlating the nucleic acid sequences of the examined specimens by way of the retrieved nucleic acid sequences (GenBank acc. CP038229.1). The outcomes of the 812 bp specimens exposed a total of thirty-eight nucleic acid variations in the various specimens when compared to the most closely related relevant standard nucleic acid sequences (GenBank acc. no. CP038229.1).