Acid resistance of E. coli O157:H7 and O26:H11 exposure to lactic acid revealed by transcriptomic analysis

The present study examined the effect of pH-independent acid resistance of Escherichia coli O157:H7 on efficacy of buffered lactic acid to decontaminate chilled beef tissue. A varied level of acid resistance was observed among the 14 strains tested. Eight strains were categorized as acid resistant, four strains as acid sensitive, and two strains demonstrated acid-inducible acid resistance. The survival of an acid-resistant (II/45/4) and acid-sensitive (IX/8/16) E. coli O157:H7 strain on chilled beef tissue treated with 1 and 2% buffered lactic acid, sterile water, or no treatment (control) was followed. A gradual reduction of E. coli O157:H7 was noticed during the 10 days of storage at 4°C for each of the treatments. Decontamination with 1 and 2% buffered lactic acid did not appreciably affect the pathogen. Differences in the pH-independent acid resistance of the strains had no effect on the efficacy of decontamination. The effect of modified atmosphere packaging (MAP) on survival of E. coli O157:H7 in red meat was also studied. MAP (40% CO2/60% N2) or vacuum did not significantly influence survival of E. coli O157:H7 on inoculated sliced beef (retail cuts) meat compared to packing in air. The relative small outgrowth of lactic acid bacteria during storage under vacuum for 28 days did not affect survival of E. coli O157:H7. Neither lactic acid decontamination nor vacuum or MAP packaging could enhance reduction of E. coli O157:H7 on beef, thus underlining the need for preventive measures to control the public health risk of E. coli O157:H7.

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Survival or Growth of Escherichia coli O157:H7 in a Model System of Fresh Meat Decontamination Runoff Waste Fluids and Its Resistance to Subsequent Lactic Acid Stress

Applied and Environmental Microbiology ◽

10.1128/aem.71.10.6228-6234.2005 ◽

2005 ◽

Vol 71 (10) ◽

pp. 6228-6234 ◽

Cited By ~ 12

Author(s):

John Samelis ◽

John N. Sofos ◽

Patricia A. Kendall ◽

Gary C. Smith

Keyword(s):

Escherichia Coli ◽

Acetic Acid ◽

Lactic Acid ◽

Acid Stress ◽

Acid Resistance ◽

Fresh Meat ◽

Sterile Saline ◽

E Coli ◽

Acid Ph ◽

Natural Flora

ABSTRACT A potential may exist for survival of and resistance development by Escherichia coli O157:H7 in environmental niches of meat plants applying carcass decontamination interventions. This study evaluated (i) survival or growth of acid-adapted and nonadapted E. coli O157:H7 strain ATCC 43895 in acetic acid (pH 3.6 ± 0.1) or in water (pH 7.2 ± 0.2) fresh beef decontamination runoff fluids (washings) stored at 4, 10, 15, or 25°C and (ii) resistance of cells recovered from the washings after 2 or 7 days of storage to a subsequent lactic acid (pH 3.5) stress. Corresponding cultures in sterile saline or in heat-sterilized water washings were used as controls. In acetic acid washings, acid-adapted cultures survived better than nonadapted cultures, with survival being greatest at 4°C and lowest at 25°C. The pathogen survived without growth in water washings at 4 and 10°C, while it grew by 0.8 to 2.7 log cycles at 15 and 25°C, and more in the absence of natural flora. E. coli O157:H7 cells habituated without growth in water washings at 4 or 10°C were the most sensitive to pH 3.5, while cells grown in water washings at 15 or 25°C were relatively the most resistant, irrespective of previous acid adaptation. Resistance to pH 3.5 of E. coli O157:H7 cells habituated in acetic acid washings for 7 days increased in the order 15°C > 10°C > 4°C, while at 25°C cells died off. These results indicate that growth inhibition by storage at low temperatures may be more important than competition by natural flora in inducing acid sensitization of E. coli O157:H7 in fresh meat environments. At ambient temperatures in meat plants, E. coli O157:H7 may grow to restore acid resistance, unless acid interventions are applied to inhibit growth and minimize survival of the pathogen. Acid-habituated E. coli O157:H7 at 10 to 15°C may maintain a higher acid resistance than when acid habituated at 4°C. These responses should be evaluated with fresh meat and may be useful for the optimization of decontamination programs and postdecontamination conditions of meat handling.

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Granulibacter bethesdensis, a Pathogen from Patients with Chronic Granulomatous Disease, Produces a Penta-Acylated Hypostimulatory Glycero-d-talo-oct-2-ulosonic Acid–Lipid A Glycolipid (Ko-Lipid A)

International Journal of Molecular Sciences ◽

10.3390/ijms22073303 ◽

2021 ◽

Vol 22 (7) ◽

pp. 3303

Author(s):

Artur Muszyński ◽

Kol A. Zarember ◽

Christian Heiss ◽

Joseph Shiloach ◽

Lars J. Berg ◽

...

Keyword(s):

Chronic Granulomatous Disease ◽

Human Blood ◽

Lipid A ◽

Acid Resistance ◽

Strong Acid ◽

Granulomatous Disease ◽

E Coli ◽

Phagocyte Nadph Oxidase ◽

Acyl Chains ◽

Ulosonic Acid

Granulibacter bethesdensis can infect patients with chronic granulomatous disease, an immunodeficiency caused by reduced phagocyte NADPH oxidase function. Intact G. bethesdensis (Gb) is hypostimulatory compared to Escherichia coli, i.e., cytokine production in human blood requires 10–100 times more G. bethesdensis CFU/mL than E. coli. To better understand the pathogenicity of G. bethesdensis, we isolated its lipopolysaccharide (GbLPS) and characterized its lipid A. Unlike with typical Enterobacteriaceae, the release of presumptive Gb lipid A from its LPS required a strong acid. NMR and mass spectrometry demonstrated that the carbohydrate portion of the isolated glycolipid consists of α-Manp-(1→4)-β-GlcpN3N-(1→6)-α-GlcpN-(1⇿1)-α-GlcpA tetra-saccharide substituted with five acyl chains: the amide-linked N-3′ 14:0(3-OH), N-2′ 16:0(3-O16:0), and N-2 18:0(3-OH) and the ester-linked O-3 14:0(3-OH) and 16:0. The identification of glycero-d-talo-oct-2-ulosonic acid (Ko) as the first constituent of the core region of the LPS that is covalently attached to GlcpN3N of the lipid backbone may account for the acid resistance of GbLPS. In addition, the presence of Ko and only five acyl chains may explain the >10-fold lower proinflammatory potency of GbKo–lipidA compared to E. coli lipid A, as measured by cytokine induction in human blood. These unusual structural properties of the G.bethesdensis Ko–lipid A glycolipid likely contribute to immune evasion during pathogenesis and resistance to antimicrobial peptides.

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The impact of indole-3-lactic acid on immature intestinal innate immunity and development: a transcriptomic analysis

Scientific Reports ◽

10.1038/s41598-021-87353-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Wuyang Huang ◽

Ky Young Cho ◽

Di Meng ◽

W. Allan Walker

Keyword(s):

Lactic Acid ◽

Mechanistic Model ◽

Transcriptomic Analysis ◽

Dependent Manner ◽

Protective Effects ◽

Very Preterm Infants ◽

Anti Inflammatory ◽

The Impact

AbstractAn excessive intestinal inflammatory response may have a role in the pathogenesis of necrotizing enterocolitis (NEC) in very preterm infants. Indole-3-lactic acid (ILA) of breastmilk tryptophan was identified as the anti-inflammatory metabolite involved in probiotic conditioned media from Bifidobacteria longum subsp infantis. This study aimed to explore the molecular endocytic pathways involved in the protective ILA effect against inflammation. H4 cells, Caco-2 cells, C57BL/6 pup and adult mice were used to compare the anti-inflammatory mechanisms between immature and mature enterocytes in vitro and in vivo. The results show that ILA has pleiotropic protective effects on immature enterocytes including anti-inflammatory, anti-viral, and developmental regulatory potentials in a region-dependent and an age-dependent manner. Quantitative transcriptomic analysis revealed a new mechanistic model in which STAT1 pathways play an important role in IL-1β-induced inflammation and ILA has a regulatory effect on STAT1 pathways. These studies were validated by real-time RT-qPCR and STAT1 inhibitor experiments. Different protective reactions of ILA between immature and mature enterocytes indicated that ILA’s effects are developmentally regulated. These findings may be helpful in preventing NEC for premature infants.

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In Vitro Inhibition of the Growth of Salmonella typhimurium and Escherichia coli 0157:H7 by Bacteria Isolated from the Cecal Contents of Adult Chickens

Journal of Food Protection ◽

10.4315/0362-028x-54.7.496 ◽

1991 ◽

Vol 54 (7) ◽

pp. 496-501 ◽

Cited By ~ 18

Author(s):

ARTHUR HINTON ◽

GEORGE E. SPATES ◽

DONALD E. CORRIER ◽

MICHAEL E. HUME ◽

JOHN R. DELOACH ◽

...

Keyword(s):

Escherichia Coli ◽

Lactic Acid ◽

Salmonella Typhimurium ◽

Mixed Cultures ◽

Enterococcus Durans ◽

E Coli ◽

Pure Cultures ◽

In Vitro Inhibition ◽

Lactic Acids

A Veillonella species and Enterococcus durans were isolated from the cecal contents of adult broilers. Mixed cultures of Veillonella and E. durans inhibited the growth of Salmonella typhimurium and Escherichia coli 0157:H7 on media containing 2.5% lactose (w/v). The growth of S. typhimurium or E. coli 0157:H7 was not inhibited by mixed cultures containing Veillonella and E. durans on media containing only 0.25% lactose or by pure cultures of Veillonella or E. durans on media containing either 0.25% or 2.5% lactose. The mixed cultures of Veillonella and E. durans produced significantly (P<0.05) more acetic, propionic, and lactic acids in media containing 2.5% lactose than in media containing 0.25% lactose. The inhibition of the enteropathogens was related to the production of lactic acid from lactose by the E. durans and the production of acetic and propionic acids from lactic acid by the Veillonella.

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Acetate and Formate Stress: Opposite Responses in the Proteome of Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.183.21.6466-6477.2001 ◽

2001 ◽

Vol 183 (21) ◽

pp. 6466-6477 ◽

Cited By ~ 149

Author(s):

Christopher Kirkpatrick ◽

Lisa M. Maurer ◽

Nikki E. Oyelakin ◽

Yuliya N. Yoncheva ◽

Russell Maurer ◽

...

Keyword(s):

Escherichia Coli ◽

Opposite Effect ◽

Stress Proteins ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Acid Resistance ◽

Luria Broth ◽

Acetyl Coa ◽

Fermentation Products ◽

E Coli

ABSTRACT Acetate and formate are major fermentation products ofEscherichia coli. Below pH 7, the balance shifts to lactate; an oversupply of acetate or formate retards growth. E. coli W3110 was grown with aeration in potassium-modified Luria broth buffered at pH 6.7 in the presence or absence of added acetate or formate, and the protein profiles were compared by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Acetate increased the steady-state expression levels of 37 proteins, including periplasmic transporters for amino acids and peptides (ArtI, FliY, OppA, and ProX), metabolic enzymes (YfiD and GatY), the RpoS growth phase regulon, and the autoinducer synthesis protein LuxS. Acetate repressed 17 proteins, among them phosphotransferase (Pta). An ackA-pta deletion, which nearly eliminates interconversion between acetate and acetyl-coenzyme A (acetyl-CoA), led to elevated basal levels of 16 of the acetate-inducible proteins, including the RpoS regulon. Consistent with RpoS activation, the ackA-pta strain also showed constitutive extreme-acid resistance. Formate, however, repressed 10 of the acetate-inducible proteins, including the RpoS regulon. Ten of the proteins with elevated basal levels in the ackA-ptastrain were repressed by growth of the mutant with formate; thus, the formate response took precedence over the loss of theackA-pta pathway. The similar effects of exogenous acetate and the ackA-pta deletion, and the opposite effect of formate, could have several causes; one possibility is that the excess buildup of acetyl-CoA upregulates stress proteins but excess formate depletes acetyl-CoA and downregulates these proteins.

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The Small Noncoding DsrA RNA Is an Acid Resistance Regulator in Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.186.18.6179-6185.2004 ◽

2004 ◽

Vol 186 (18) ◽

pp. 6179-6185 ◽

Cited By ~ 65

Author(s):

Richard A. Lease ◽

Dorie Smith ◽

Kathleen McDonough ◽

Marlene Belfort

Keyword(s):

Escherichia Coli ◽

Stress Response ◽

Resistance Genes ◽

Acid Resistance ◽

Dna Arrays ◽

E Coli ◽

Specific Mrnas ◽

Steady State Levels ◽

Control Translation ◽

K 12

ABSTRACT DsrA RNA is a small (87-nucleotide) regulatory RNA of Escherichia coli that acts by RNA-RNA interactions to control translation and turnover of specific mRNAs. Two targets of DsrA regulation are RpoS, the stationary-phase and stress response sigma factor (σs), and H-NS, a histone-like nucleoid protein and global transcription repressor. Genes regulated globally by RpoS and H-NS include stress response proteins and virulence factors for pathogenic E. coli. Here, by using transcription profiling via DNA arrays, we have identified genes induced by DsrA. Steady-state levels of mRNAs from many genes increased with DsrA overproduction, including multiple acid resistance genes of E. coli. Quantitative primer extension analysis verified the induction of individual acid resistance genes in the hdeAB, gadAX, and gadBC operons. E. coli K-12 strains, as well as pathogenic E. coli O157:H7, exhibited compromised acid resistance in dsrA mutants. Conversely, overproduction of DsrA from a plasmid rendered the acid-sensitive dsrA mutant extremely acid resistant. Thus, DsrA RNA plays a regulatory role in acid resistance. Whether DsrA targets acid resistance genes directly by base pairing or indirectly via perturbation of RpoS and/or H-NS is not known, but in either event, our results suggest that DsrA RNA may enhance the virulence of pathogenic E. coli.

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Inactivation of Escherichia coli O157:H7, Salmonella enterica Serotype Enteritidis, and Listeria monocytogenes on Lettuce by Hydrogen Peroxide and Lactic Acid and by Hydrogen Peroxide with Mild Heat

Journal of Food Protection ◽

10.4315/0362-028x-65.8.1215 ◽

2002 ◽

Vol 65 (8) ◽

pp. 1215-1220 ◽

Cited By ~ 107

Author(s):

CHIA-MIN LIN ◽

SARAH S. MOON ◽

MICHAEL P. DOYLE ◽

KAY H. McWATTERS

Keyword(s):

Escherichia Coli ◽

Hydrogen Peroxide ◽

Lactic Acid ◽

Listeria Monocytogenes ◽

Salmonella Enterica ◽

Salmonella Enteritidis ◽

Sensory Characteristics ◽

Escherichia Coli O157 ◽

E Coli ◽

Log Reduction

Iceberg lettuce is a major component in vegetable salad and has been associated with many outbreaks of foodborne illnesses. In this study, several combinations of lactic acid and hydrogen peroxide were tested to obtain effective antibacterial activity without adverse effects on sensory characteristics. A five-strain mixture of Escherichia coli O157:H7, Salmonella enterica serotype Enteritidis, and Listeria monocytogenes was inoculated separately onto fresh-cut lettuce leaves, which were later treated with 1.5% lactic acid plus 1.5% hydrogen peroxide (H2O2) at 40°C for 15 min, 1.5% lactic acid plus 2% H2O2 at 22°C for 5 min, and 2% H2O2 at 50°C for 60 or 90 s. Control lettuce leaves were treated with deionized water under the same conditions. A 4-log reduction was obtained for lettuce treated with the combinations of lactic acid and H2O2 for E. coli O157:H7 and Salmonella Enteritidis, and a 3-log reduction was obtained for L. monocytogenes. However, the sensory characteristics of lettuce were compromised by these treatments. The treatment of lettuce leaves with 2% H2O2 at 50°C was effective not only in reducing pathogenic bacteria but also in maintaining good sensory quality for up to 15 days. A ≤4-log reduction of E. coli O157:H7 and Salmonella Enteritidis was achieved with the 2% H2O2 treatment, whereas a 3-log reduction of L. monocytogenes was obtained. There was no significant difference (P > 0.05) between pathogen population reductions obtained with 2% H2O2 with 60- and 90-s exposure times. Hydrogen peroxide residue was undetectable (the minimum level of sensitivity was 2 ppm) on lettuce surfaces after the treated lettuce was rinsed with cold water and centrifuged with a salad spinner. Hence, the treatment of lettuce with 2% H2O2 at 50°C for 60 s is effective in initially reducing substantial populations of foodborne pathogens and maintaining high product quality.

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A Clean-In-Place Type Sanitation Method Validation for a Benchtop Meat Grinder

Meat and Muscle Biology ◽

10.22175/mmb.10732 ◽

2019 ◽

Vol 3 (2) ◽

Author(s):

C. E. Rayfield ◽

R. Jadeja ◽

S. Billups

Keyword(s):

Lactic Acid ◽

Foodborne Pathogens ◽

Peracetic Acid ◽

Deionized Water ◽

Cross Contamination ◽

Direct Plating ◽

Water Ice ◽

E Coli ◽

Different Types ◽

Low Levels

ObjectivesThis research is designed to validate a novel clean-in-place type antimicrobial ice-based meat grinder sanitation method.Materials and MethodsFour different types of antimicrobial ice were prepared from peracetic acid (PAA, 350 mg/L) and combination PAA with 2% FreshFX® (PAAF), 2% Paradigm® (PAAP) and 2% lactic acid (PAAL). The grinders were inoculated by processing 400 g beef trim containing 400 μL of E. coli O157:H7 or S. Typhimurium DT 104 suspensions at 8.4 to 8.7 (high inoculation) and 5.3 to 5.5 (low inoculation) log CFU/mL. Each meat grinder was then treated by processing 1000 g of antimicrobial ice and 500 mL of corresponding antimicrobial solution. At the end of each treatment, 400 g un-inoculated beef was processed through the meat grinder, and the resulting ground beef was then analyzed for the presence of target pathogens by direct plating and after enrichment. Efficacies of antimicrobial ice-based treatments were compared with 1000 g deionized water ice + 500 mL deionized water (DI), and no treatment (NT) controls.ResultsAll antimicrobial ice treatments were able to reduce cross-contamination to non-detectable levels from the meat grinders inoculated at the low levels of pathogens, but after enrichment, target pathogens were detected in all the samples. Recoveries from the meat grinder inoculated with high levels of pathogens ranged from 5.95 to 3.50 log CFU/g and 5.86 to 3.46 log CFU/g for E. coli O157:H7 and S. Typhimurium DT 104, respectively. All antimicrobial ice treatments were significantly (p ≤ 0.05) more effective in reducing cross-contamination in comparison of NT and DI controls. The microbial reductions achieved by different antimicrobial ice treatments were not significantly (p ≤ 0.05) different from each other.ConclusionThe antimicrobial ice-based meat grinder sanitation technique could effectively reduce foodborne pathogens from meat grinders without needing meat grinder disassembly.

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Lactic Acid Bacteria (Lactobacillus bulgaricus and Streptococcus thermophillus) in Yogurt Inhibit the Growth of Escherichia coli, Salmonella typhimurium, and Shigella sp. In Vitro

Jurnal Kedokteran Brawijaya ◽

10.21776/ub.jkb.2021.031.04.2 ◽

2021 ◽

Vol 31 (4) ◽

pp. 2

Author(s):

IDSAP Peramiarti

Keyword(s):

Escherichia Coli ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Salmonella Typhimurium ◽

Pathogenic Bacteria ◽

Test Method ◽

P Value ◽

E Coli ◽

Significant Difference

Diarrhea is defecation with a frequency more often than usual (three times or more) a day (10 mL/kg/day) with a soft or liquid consistency, even in the form of water alone. Pathogenic bacteria, such as Escherichia coli, Salmonella typhimurium, and Shigella sp., play a role in many cases, to which antibiotics are prescribed as the first-line therapy. However, since antibiotic resistance cases are often found, preventive therapies are needed, such as consuming yogurt, which is produced through a fermentation process by lactic acid bacteria (LAB). This research aimed to determine the activity of lactic acid bacteria (Liactobacillus bulgaricus and Streptococcus thermophilus) in yogurt in inhibiting the growth of the pathogenic bacteria E. coli, S. typhimurium, and Shigella sp. The research applied in vitro with the liquid dilution test method and the true experimental design research method with post-test-only and control group design. The design was used to see the inhibitory effect of yogurt LAB on the growth of E. coli, S. typhimurium, and Shigell sp. to compare the effect of several different yogurt concentrations, namely 20%, 40%, 60%, and 80%. The results of the Least Significance Different analysis showed that there was a significant difference between yogurt with a concentration of 0% and that with various concentrations in inhibiting the growth of E. coli, S. typhimurium, and Shigella sp. with a p-value of <0.05. Whereas, there was no significant difference in the various concentrations of yogurt in inhibiting the growth of the three kinds of bacteria with a p-value of > 0.05.<p class="Default" align="center"> </p>

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