Infectious disease: diarrhea

G, de Bruyn

doi:10.1136/ewjm.172.6.409

Cited by 9 publications

(7 citation statements)

References 23 publications

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“…Enteric pathogens are responsible for about two million deaths annually and the diarrhoeal illness they cause results in billions of dollars of treatment costs (de Bruyn, 2000). Salmonella species are some of the most common pathogens associated with sporadic diarrhoea in adults living in developed countries (de Bruyn, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Differential expression of NiFe uptake-type hydrogenase genes in Salmonella enterica serovar Typhimurium

2007

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Salmonella enterica serovar Typhimurium possesses three similar NiFe hydrogenases important to its virulence. Here we show that the three hydrogenase operons hyb, hya and hyd are expressed under different environmental conditions and are subject to control by different regulatory proteins. Hydrogenase promoter-lacZ fusion plasmids were transferred into the wild-type strain or into arcA, fnr, iscR, narL and narP deletion mutants, or into a fnr/arcA double mutant. The hyb promoter had highest b-galactosidase activity under growth conditions promoting anaerobic respiration (glycerol plus fumarate) and may be subject to glucose repression, since cells grown with glucose had about half the transcriptional activity of cells grown with mannose. Based on the phenotype of regulatory mutant strains, IscR represses hyb aerobically, and ArcA plays a role in both hyb and hyd regulation. The hyd promoter had about five times more activity in cells grown under aerobic conditions compared to anaerobic levels, and its activity tripled in an arcA mutant grown anaerobically. The hya promoter had the highest activity when cells were grown anaerobically with glucose, and the growth yield of the hya mutant was about 25 % lower than for wild-type cells grown fermentatively, suggesting that Hya may be utilized during fermentation. The hya promoter is repressed by nitrate and this repression was abolished when the NarL-binding site was mutated, or in a narL mutant background. FNR is involved in hyb and hya regulation, since b-galactosidase activity decreased significantly in a fnr mutant. These findings suggest that the three hydrogenases are used under different conditions, likely enhancing the pathogen's capacity to survive in a variety of environments.

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Section: Introductionmentioning

confidence: 99%

“…Salmonella species are some of the most common pathogens associated with sporadic diarrhoea in adults living in developed countries (de Bruyn, 2000). According to the World Health Organization, the cost associated with Salmonella infections alone is estimated at three billion dollars annually in the United States.…”

Section: Introductionmentioning

confidence: 99%

Differential expression of NiFe uptake-type hydrogenase genes in Salmonella enterica serovar Typhimurium

2007

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“…Salmonella species are some of the most common pathogens associated with food-borne illness in adults living in developed countries (5) and are responsible for about 30% of food-related deaths in the United States (17). Salmonella enterica serovar Typhimurium causes gastroenteritis in humans and a typhoid fever-like disease in mice (25).…”

mentioning

confidence: 99%

Salmonella enterica Serovar Typhimurium NiFe Uptake-Type Hydrogenases Are Differentially Expressed In Vivo

Zbell

Maier

2008

Infect Immun

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Salmonella enterica serovar Typhimurium, a common enteric pathogen, possesses three NiFe uptake-type hydrogenases. The results from mouse infection studies suggest that the H 2 oxidation capacity provided by these hydrogenases is important for virulence. Since the three enzymes are similar in structure and function, it may be expected that they are utilized under different locations and times during an infection. A recombination-based method to examine promoter activity in vivo (RIVET) was used to determine hydrogenase gene expression in macrophages, polymorphonuclear leukocyte (PMN)-like cells, and a mouse model of salmonellosis. The hyd and hya promoters showed increased expression in both murine macrophages and human PMN-like cells compared to that in the medium-only controls. Quantitative reverse transcription-PCR results suggested that hyb is also expressed in phagocytes. A nonpolar hya mutant was compromised for survival in macrophages compared to the wild type. This may be due to lower tolerance to acid stress, since the hya mutant was much more acid sensitive than the wild type. In addition, hya mutant cells were internalized by macrophages the same as wild-type cells. Mouse studies (RIVET) indicate that hyd is highly expressed in the liver and spleen early during infection but is expressed poorly in the ileum in infected animals. Late in the infection, the hyd genes were expressed at high levels in the ileum as well as in the liver and spleen. The hya genes were expressed at low levels in all locations tested. These results suggest that the hydrogenases are used to oxidize hydrogen in different stages of an infection.

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“…A recent overview of these trials concluded that fluoroquinolone treatment decreased the duration of diarrhea by a mean of 0.85 days; other antibiotics offered no benefit. Adverse side effects were more common in the antibiotic-treated patients [51].…”

Section: Empiric Antibiotic Therapy Of Gastroenteritismentioning

confidence: 92%

Foodborne illnesses

Gill

Hamer

2001

Curr Treat Options Gastro

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Foodborne illnesses cause a substantial human and financial burden. Despite sanitary infrastructure improvements, the incidence of foodborne bacterial infections due to non-typhoidal salmonellae (NTS), Campylobacter jejuni, and enterohemorrhagic Escherichia coli (EHEC) has risen over the last two decades. Overall, viruses account for two thirds of all foodborne illness. Most foodborne illnesses are self-limited. Supportive therapy with rehydration and the correction of electrolyte abnormalities is usually sufficient. Antibiotics play a beneficial role in the treatment of patients with certain foodborne diseases, such as listeriosis and typhoid fever, and all patients with tissue invasive or bloodstream infections. Immunocompromised patients should be treated presumptively. Antibiotics are of variable efficacy for the treatment of many infections limited to the gastrointestinal tract, and recommendations differ between pathogens. Antibiotics are generally helpful for shigellosis and cholera, and possibly beneficial for campylobacteriosis. However, antibiotics are potentially harmful in uncomplicated NTS and EHEC gastroenteritis and generally should not be used. Toxin-mediated food poisoning usually does not require specific therapy. The exception is botulism, for which botulinum antitoxin is highly efficacious if used early in the course of illness. Empiric therapy for gastroenteritis is possibly beneficial, though the magnitude of benefit is modest and incurs the risk of inadvertently treating NTS or EHEC. The choice of antibiotic should be based on local resistance patterns and the results of susceptibility testing.

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Infectious disease: diarrhea

Cited by 9 publications

References 23 publications

Differential expression of NiFe uptake-type hydrogenase genes in Salmonella enterica serovar Typhimurium

Differential expression of NiFe uptake-type hydrogenase genes in Salmonella enterica serovar Typhimurium

Salmonella enterica Serovar Typhimurium NiFe Uptake-Type Hydrogenases Are Differentially Expressed In Vivo

Foodborne illnesses

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