Microbiology Critique Paper: Intestinal Metabolites and Signals

This report presents a critical analysis of a research paper focusing on the interactions between intestinal bacteria, microbial metabolites, and chemical signaling within the host-microbiota-pathogen context. The paper explores how enteric foodborne pathogens, such as Salmonella and Escherichia species, modulate their virulence factors in response to signals. The critique highlights the paper's strengths, such as the detailed discussion of EHEC chemical signaling, and also identifies areas for improvement, including the limited discussion of bacterial interactions beyond those of Gram-negative bacteria and the omission of certain metabolic processes. The analysis also points out some inconsistencies and biases in the paper's discussion, particularly in its focus on specific pathogens and signaling pathways. The report concludes by emphasizing the significance of understanding these interactions for potential treatment strategies, particularly for gastroenteritis.

Running head: MICROBIOLOGY
CRITIQUE PAPER
Name of the Student
Name of the University
Author Note

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Intestinal bacteria have been found to use microbial metabolites from the microbiota and the
chemical signaling has been found to play a major role in cell to cell communication
associated with the regulation of different cellular functions. Most of the enteric foodborne
pathogens studied in the paper include Salmonella and Escherichia species. These groups of
bacteria have been found to modulate the expression of their virulence factors which have
been found to occur in response to signals (Lustri, Sperandio & Moreira, 2017). This essay
will discuss a critique of the intestinal metabolite and their signals present in the Host
Microbiota Pathogen Interactions.
This paper has discussed the commensalism interaction between pathogens in the human gut.
This paper also discussed that the intestinal mucosa forms a physical barrier that protects the
microbiota on the luminal side. However, the ratio between bacteria and host cells has still
been found to be unsolved. This factor was not discussed or solved by this research study
also. However, the skipping of this discussion in this paper is justified due to the fact that this
ration does not play a significant role in the host-microbiota interactions in the gut. The total
composition of intestinal mucosa has been found to be impacted by lifestyle, diet and host
genetics. The primary challenge of the presence of toxic chemicals in the intestines has been
found to be faced by the microbiota community of the human gut. This paper discussed this
section in detail also stating about cationic ions and their effect on the membranes and
interactions of the population of gut microbiota. This paper talked only of Gram-negative
bacteria and their association with the human gut, skipping other bacterial groups and their
interactions with other populations of gut microbiota (Cameron et al., 2019). Bacterial
metabolite sensing section failed to discuss the various metabolic processes used by a
bacteria, to utilize the sensed metabolite. However, this paper successfully described the fact
that cell to cell interaction and communication has been found to regulate their virulence
mechanisms and cause gastroenteritis. For example, the discussion on Bacillus in breaking

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down plant starches and other complex carbohydrate molecules has been found to control the
cell to cell interaction and commensalism since other microbiota communities cannot utilize
the same. However, this paper again skipped a specific point at this step where it was
necessary to talk of other groups of bacteria who can utilize plant starch in the same way as
Bacillus does. Thus, it can be stated that competition interaction is not discussed in this paper.
One of the most essential features of this paper is that it discussed the EHEC chemical
signaling in a proper manner without missing or skipping any of the points. Even, animal
models have been properly discussed associated with their effects of EHEC interactions. This
paper has also discussed the chemical signaling in S. Typhimurium in detail but failed to
discuss the chemical signally process of other groups of bacteria living in the human gut
(Gestal, Whitesides & Harvill, 2019). However, it has been observed that while discussing
metabolite influences of EHEC pathogens, Shiga toxin has been brought forward whereas the
previous discussion was done on S. Typhimurium. This factor induced a sense of bias in this
paper which can be stated to be brought forth due to changes in the discussion as stated
before. Very less discussion has been done on other bacterial interactions and their
importance during EHC pathogenesis (Tobias & Bode, 2019). All the three chemical
signaling processes discussed in this paper for bacteria has been found to be clear, without
any points being skipped. Various approaches have been derived in order to interfere with the
bacterial pathogenesis, which states that the chemical signaling process can be hampered by
external interferences. This process has been found as a treatment strategy in various cases
involving gastroenteritis.
On a concluding note, it can be said that Intestinal bacteria have been found to use microbial
metabolites from the microbiota and the chemical signaling has been found to play a
significant role in cell to cell communication associated with the regulation of different
cellular functions. Most of the enteric foodborne pathogens studied in the paper include

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Salmonella and Escherichia species. The critique has shown that these groups of bacteria
have been found to modulate the expression of their virulence factors which have been found
to occur in response to signals. This essay has successfully discussed a critique of the
intestinal metabolite and their signals present in the Host Microbiota Pathogen Interactions.

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References
Cameron, E. A., Gruber, C. C., Ritchie, J. M., Waldor, M. K., & Sperandio, V. (2018). The
QseG lipoprotein impacts the virulence of enterohemorrhagic Escherichia coli and
Citrobacter rodentium and regulates flagellar phase variation in Salmonella enterica
serovar typhimurium. Infection and immunity, 86(4), e00936-17.
Gestal, M. C., Whitesides, L. T., & Harvill, E. T. (2019). Integrated signaling pathways
mediate Bordetella immunomodulation, persistence, and transmission. Trends in
microbiology, 27(2), 118-130.
Lustri, B. C., Sperandio, V., & Moreira, C. G. (2017). Bacterial chat: intestinal metabolites
and signals in host-microbiota-pathogen interactions. Infection and immunity, 85(12),
e00476-17.
Tobias, N. J., & Bode, H. B. (2019). Heterogeneity in bacterial specialized
metabolism. Journal of molecular biology.
Xavier, K. B. (2018). Bacterial interspecies quorum sensing in the mammalian gut
microbiota. Comptes rendus biologies, 341(5), 297-299.