Abstract:Serratia marcescens
is ubiquitous in the environment and can survive in water, soil, plants, insects, and animals, and it can also cause infections in humans. In the face of disturbances such as oxidative or low-pH stress, bacteria adapt, survive, and recover through several mechanisms, including changes in their secretome.
“…To our surprise, in vitro survival of the 6KO CR-Kp was comparable to that of WT CR-Kp in response to several broadly utilized bacterial stressors, including H 2 O 2 , human serum, and bile acids ( Figure 5a–c ). Similarly, when testing acidic stress resistance, biofilm formation or surface hydrophobicity, which were other reported roles for individual DUF1471-encoding genes, 44–48 , 51 we detected no difference between 6KO and WT CR-Kp (data not shown). Figure 5.…”
Carbapenem-resistant
Klebsiella pneumoniae
(CR-Kp) is a significant threat to public health worldwide. The primary reservoir for CR-Kp is the intestinal tract. There, the bacterium is usually present at low density but can bloom following antibiotic treatment, mostly in hospital settings. The impact of disturbances in the intestinal environment on the fitness, survival, expansion, and drug susceptibility of this pathogen is not well-understood, yet it may be relevant to devise strategies to tackle CR-Kp colonization and infection. Here, we adopted an
in vivo
model to examine the transcriptional adaptation of a CR-Kp clinical isolate to immune activation in the intestine. We report that as early as 6 hours following host treatment with anti-CD3 antibody, CR-Kp underwent rapid transcriptional changes including downregulation of genes involved in sugar utilization and amino acid biosynthesis and upregulation of genes involved in amino acid uptake and catabolism, antibiotic resistance, and stress response. In agreement with these findings, treatment increased the concentration of oxidative species and amino acids in the mouse intestine. Genes encoding for proteins containing the domain of unknown function (DUF) 1471 were strongly upregulated, however their deletion did not impair CR-Kp fitness i
n vivo
upon immune activation. Transcription factor enrichment analysis identified the global regulator cAMP-Receptor Protein, CRP, as a potential orchestrator of the observed transcriptional signature. In keeping with the recognized role of CRP in regulating utilization of alternative carbon sources,
crp
deletion in CR-Kp resulted in strongly impaired gut colonization, although this effect was not amplified by immune activation. Thus, following intestinal colonization, which occurs in a CRP-dependent manner, CR-Kp can rapidly respond to immune cues by implementing a well-defined and complex transcriptional program whose direct relevance toward bacterial fitness warrants further investigation. Additional analyses utilizing this model may identify key factors to tackle CR-Kp colonization of the intestine.
“…To our surprise, in vitro survival of the 6KO CR-Kp was comparable to that of WT CR-Kp in response to several broadly utilized bacterial stressors, including H 2 O 2 , human serum, and bile acids ( Figure 5a–c ). Similarly, when testing acidic stress resistance, biofilm formation or surface hydrophobicity, which were other reported roles for individual DUF1471-encoding genes, 44–48 , 51 we detected no difference between 6KO and WT CR-Kp (data not shown). Figure 5.…”
Carbapenem-resistant
Klebsiella pneumoniae
(CR-Kp) is a significant threat to public health worldwide. The primary reservoir for CR-Kp is the intestinal tract. There, the bacterium is usually present at low density but can bloom following antibiotic treatment, mostly in hospital settings. The impact of disturbances in the intestinal environment on the fitness, survival, expansion, and drug susceptibility of this pathogen is not well-understood, yet it may be relevant to devise strategies to tackle CR-Kp colonization and infection. Here, we adopted an
in vivo
model to examine the transcriptional adaptation of a CR-Kp clinical isolate to immune activation in the intestine. We report that as early as 6 hours following host treatment with anti-CD3 antibody, CR-Kp underwent rapid transcriptional changes including downregulation of genes involved in sugar utilization and amino acid biosynthesis and upregulation of genes involved in amino acid uptake and catabolism, antibiotic resistance, and stress response. In agreement with these findings, treatment increased the concentration of oxidative species and amino acids in the mouse intestine. Genes encoding for proteins containing the domain of unknown function (DUF) 1471 were strongly upregulated, however their deletion did not impair CR-Kp fitness i
n vivo
upon immune activation. Transcription factor enrichment analysis identified the global regulator cAMP-Receptor Protein, CRP, as a potential orchestrator of the observed transcriptional signature. In keeping with the recognized role of CRP in regulating utilization of alternative carbon sources,
crp
deletion in CR-Kp resulted in strongly impaired gut colonization, although this effect was not amplified by immune activation. Thus, following intestinal colonization, which occurs in a CRP-dependent manner, CR-Kp can rapidly respond to immune cues by implementing a well-defined and complex transcriptional program whose direct relevance toward bacterial fitness warrants further investigation. Additional analyses utilizing this model may identify key factors to tackle CR-Kp colonization of the intestine.
“…The reduction in pH of the spoiled samples indicates the growth of acidproducing bacteria or yeast during the storage of FSSBs. Culture-dependent analyses identified S. marcescens, which is known for its ability to thrive in this pH range, 23,36 as a likely contributor to spoilage. Conversely, the abundance of P. fluorescens, typically reported as the dominant species in precooked frozen food, was reduced in spoiled samples.…”
Section: ■ Discussionmentioning
confidence: 99%
“…Culture-dependent analyses identified S. marcescens, which is known for its ability to thrive in this pH range, , as a likely contributor to spoilage. Conversely, the abundance of P.…”
Section: Discussionmentioning
confidence: 99%
“…The determination of pH, a W , moisture content, cell density, and metabolite concentrations was performed in triplicate, and the results were subjected to one-way analysis of variance . The values are expressed as the mean values ± the standard deviation.…”
Section: Methodsmentioning
confidence: 99%
“…The determination of pH, a W , moisture content, cell density, and metabolite concentrations was performed in triplicate, and the results were subjected to one-way analysis of variance. 23 The values are expressed as the mean values ± the standard deviation. Statistical analysis was performed using SPSS software (version 26.0; SPSS, Chicago, IL, USA), and significant differences among the values were calculated using Tukey's procedure at P < 0.05.…”
Brown discoloration was observed in the crust of commercial frozen steamed stuffed buns (FSSBs) during resteaming. Culture-dependent and culture-independent analyses demonstrated that Serratia marcescens, a prodigiosin-producing species, was more abundant in spoiled samples than in unspoiled samples. Inoculation of experimental FSSBs with S. marcescens isolated from spoiled FSSBs confirmed that this species causes brown discoloration of FSSBs during resteaming. S. marcescens formed prodigiosin only between 15 and 28 °C but brown discoloration appeared only upon resteaming after storage at 4 °C. Highperformance liquid chromatography analyses revealed that prodigiosin was absent from yellow−brown FSSBs. The pigmentation observed during resteaming is thus likely attributable to the intermediate 2-methyl-3-amylpyrrole. These findings provide valuable insights into the microbial contamination of FSSBs and will facilitate the prevention of spoilage of FSSBs.
Introduction. We describe an outbreak of Serratia marcescens (S. marcescens) infection in the neonatal intensive care unit at Women’s Hospital in Sinaloa, Mexico. Methods. In April 2021, an outbreak of S. marcescens infection was identified. A case was identified as any patient who tested positive for S. marcescens and showed signs of an infectious process. Results. S. marcescens was isolated from the blood cultures of 15 neonates with clinical signs of neonatal sepsis. Statistical analysis showed that all neonates had an invasive medical device. The problem was controlled after hospital hygiene and sanitation measures were strengthened. Conclusion. The study provides evidence of an outbreak of nosocomial bacteremia due to the cross-transmission of S. marcescens. The findings highlight the need for hospitals to implement strict hygiene measures, especially regarding hand washing, to prevent future outbreaks.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
