Preliminary investigation of impact of temperature on in vitro growth of American Type Culture Collection strains of staphylococcal bacteria in the planktonic state

Temperature is a critical environmental factor influencing bacterial growth, and antimicrobial susceptibility testing in vitro. This study aimed to investigate the temperature-dependent growth dynamics, doubling time (dT), and area under the curve (AUC) of American Type Culture Collection (ATCC) strains of Staphylococcus aureus (SA), Staphylococcus pseudintermedius (SP), and Staphylococcus epidermidis (SE) at 25°C, 30°C, and 37°C to enhance understanding of their proliferation under varying environmental conditions.Bacterial strains were cultured in Mueller-Hinton Broth (MHB), and optical density at 600 nm (OD600) was measured hourly over an 18-hour period. Growth curves were generated, dT was calculated during the exponential phase, and AUC was used to assess cumulative growth. At 25°C, SA and SE demonstrated significantly greater growth than SP at specific time points (p<0.015). At 30°C, SA showed significantly higher growth than SP at 8 and 11 hours (p<0.0001), while SE exhibited reduced growth at 5 and 8 hours (p<0.0014). At 37°C, SA significantly outgrew both SP and SE from 4 to 18 hours (p<0.0001). SA had the shortest dT across all temperatures (25°C: 3.41 h, 30°C: 2.85 h, 37°C: 1.92 h), while SP had a longer dT, particularly at 37°C (2.37 h). SE maintained relatively stable dT values. SA also showed consistently higher AUC values, indicating greater cumulative growth.Temperature significantly impacts the growth profiles of SA, SP, and SE. SA demonstrated the most robust growth under all conditions, emphasizing the need to consider temperature in experimental design and clinical interpretations of bacterial behavior.