Systematic review identifies recurrent fungal and bacterial genera in indoor environments across Gulf Cooperation Council countries.

This review investigates indoor microbial contamination across Gulf Cooperation Council (GCC) countries (Saudi Arabia, the United Arab Emirates, Qatar, Kuwait, Bahrain, and Oman) over the last decade. Investigations on indoor fungal and bacterial contamination took place in different building types (residential, commercial, educational, and healthcare buildings). Across the studies, recurrent fungal genera (Aspergillus, Penicillium, Cladosporium, Alternaria, and Fusarium) and common bacterial genera (Staphylococcus, Bacillus, and Micrococcus) were frequently reported in various samples as airborne bioaerosols, on damp building materials, on heating, ventilation and air conditioning (HVAC) components, and in settled dust. These loads are often exacerbated by regional heat and humidity conditions, dust intrusion, and heavy reliance on air conditioning. Reported concentration ranges of microbial contaminants are accompanied by health-related risk assessments for the most identified microbial taxa indoors. Significant inadequacies are noted in this review, including inconsistent country coverage, a shortage of studies on indoor biological contaminants, and a lack of comparable air, surface, and dust sampling. The need for regional recommendations, standardized sampling and reporting procedures, moisture and condensation control, strict HVAC cleanliness and filtration, the deterioration of indoor air quality, the danger of infectious exposure and regular monitoring for direct remediation are highlighted here. These actions can reduce microbial loads and improve indoor environmental sustainability across the region.