Analisis mikrobiologis kualitas udara di lingkungan Universitas Negeri Medan - Lydia Siburian; Fatiha Salma Siregar; Putri Khairani; Gracelda E. Pardede; Rani Simanjuntak; Najwa Athifah; Marlinda Nilan Sari Rangkuti; Adelia Febriyossa (Sanitasi: Jurnal Kesehatan Lingkungan, 2026)
Kualitas mikrobiologi udara merupakan salah satu indikator penting dalam penilaian kesehatan lingkungan karena keberadaan mikroorganisme di udara berpotensi mempengaruhi kesehatan manusia. Penelitian ini dilakukan untuk menganalisis kualitas mikrobiologi udara berdasarkan kepadatan dan karakteristik bakteri menggunakan metode passive air sampling. Pengambilan sampel udara dilakukan pada tiga lokasi dengan tingkat aktivitas yang berbeda menggunakan media Nutrient Agar (NA). Sampel yang diperoleh diinkubasi pada suhu 37°C selama 24–48 jam, kemudian dilakukan perhitungan jumlah koloni bakteri dalam satuan Colony Forming Unit (CFU), pengamatan morfologi koloni, pewarnaan Gram, serta uji biokimia yang meliputi uji katalase, Triple Sugar Iron Agar (TSIA), Sulfide Indole Motility (SIM), dan Simmons Citrate. Hasil penelitian menunjukkan bahwa kepadatan mikroorganisme udara tertinggi ditemukan pada lokasi Gerbang 1 sebesar 3,07 × 10³ CFU/m³, sedangkan Gerbang 2 dan Gerbang 4 masing-masing sebesar 1,67 × 10³ CFU/m³ dan 1,62 × 10³ CFU/m³. Karakterisasi bakteri menunjukkan adanya variasi morfologi koloni serta dominasi bakteri Gram positif berbentuk basil dan beberapa isolat Gram negatif berbentuk kokobasil. Hasil uji biokimia mengindikasikan adanya keragaman karakter fisiologis antar isolat bakteri. Penelitian ini menyimpulkan bahwa kualitas mikrobiologi udara pada lokasi pengamatan menunjukkan variasi kepadatan dan karakteristik bakteri yang dipengaruhi oleh kondisi lingkungan dan aktivitas di sekitar lokasi sampling.   Abstract: Air microbiological quality is one of the key indicators in environmental health assessments, as the presence of microorganisms in the air has the potential to affect human health. This study was conducted to analyse air microbiological quality based on bacterial density and characteristics using the passive air sampling method. Air sampling was carried out at three locations with different activity levels using Nutrient Agar (NA) as the culture medium. The samples obtained were incubated at 37°C for 24–48 hours, followed by the counting of bacterial colonies in Colony Forming Units (CFU), observation of colony morphology, Gram staining, and biochemical tests including the catalase test, Triple Sugar Iron Agar (TSIA), Sulphide Indole Motility (SIM), and Simmons Citrate tests. The results of the study showed that the highest density of airborne microorganisms was found at Gate 1, at 3.07 × 10³ CFU/m³, whilst Gate 2 and Gate 4 recorded 1.67 × 10³ CFU/m³ and 1.62 × 10³ CFU/m³ respectively. Characterisation of the bacteria revealed variations in colony morphology, with a predominance of Gram-positive bacilli and several Gram-negative coccobacilli isolates. Biochemical test results indicated diversity in the physiological characteristics among the bacterial isolates. This study concluded that the microbiological quality of the air at the observation sites showed variations in bacterial density and characteristics influenced by environmental conditions and activity.