Comparative Transcriptomic Analysis of Staphylococcus aureus Reveals the Genes Involved in Survival at Low Temperature

Abstract

In food processing, the temperature is usually reduced to limit bacterial reproduction and maintain food safety. However, Staphylococcus aureus can adapt to low temperatures by controlling gene expression and protein activity, although its survival strategies normally vary between different strains. The present study investigated the molecular mechanisms of S. aureus with different survival strategies in response to low temperatures (4 °C). The survival curve showed that strain BA-26 was inactivated by 6.0 logCFU/mL after 4 weeks of low-temperature treatment, while strain BB-11 only decreased by 1.8 logCFU/mL. Intracellular nucleic acid leakage, transmission electron microscopy, and confocal laser scanning microscopy analyses revealed better cell membrane integrity of strain BB-11 than that of strain BA-26 after low-temperature treatment. Regarding oxidative stress, the superoxide dismutase activity and the reduced glutathione content in BB-11 were higher than those in BA-26; thus, BB-11 contained less malondialdehyde than BA-26. RNA-seq showed a significantly upregulated expression of the fatty acid biosynthesis in membrane gene (fabG) in BB-11 compared with BA-26 because of the damaged cell membrane. Then, catalase (katA), reduced glutathione (grxC), and peroxidase (ahpC) were found to be significantly upregulated in BB-11, leading to an increase in the oxidative stress response, but BA-26-related genes were downregulated. NADH dehydrogenase (nadE) and α-glucosidase (malA) were upregulated in the cold-tolerant strain BB-11 but were downregulated in the cold-sensitive strain BA-26, suggesting that energy metabolism might play a role in S. aureus under low-temperature stress. Furthermore, defense mechanisms, such as those involving asp23, greA, and yafY, played a pivotal role in the response of BB-11 to stress. The study provided a new perspective for understanding the survival mechanism of S. aureus at low temperatures.

Comparison of microbial molecular diagnosis efficiency within unstable template metagenomic DNA samples between qRT-PCR and chip-based digital PCR platforms

“…The greA gene encodes a transcription elongation factor that affects bacterial gene transcription by regulating gene promoters, thereby regulating the environmental adaptation of bacteria [ 11 ]. In addition, the greA gene is recognized as a bacterial housekeeping gene, which, like the bacterial 16S ribosomal RNA, is an evolutionarily conserved transcription factor widely distributed in prokaryotes [ 12 ].…”

ArcR contributes to tolerance to fluoroquinolone antibiotics by regulating katA in Staphylococcus aureus

“…Here, we demonstrated that KatA was involved in bacterial tolerance to oxidative stress and subsequent tolerance to fluoroquinolone antibiotics. Additionally, KatA affected the survival of S. aureus at low temperature (Masmoudi et al, 2010;Suo et al, 2022). PerR functions as a major repressed regulator of the response to H 2 O 2 in S. aureus, which replaces OxyR in many Gram-positive bacteria (Mongkolsuk and Helmann, 2002;Dubbs and Mongkolsuk, 2012).…”