scholarly journals In vitro susceptibility of Helicobacter pylori to, and in vivo suppression by, antimicrobials used in selective decontamination of the digestive tract

2000 ◽  
Vol 46 (5) ◽  
pp. 803-805 ◽  
Author(s):  
P. H. J. van der Voort
Keyword(s):  
Helicobacter Pylori ◽  
Digestive Tract ◽  
Selective Decontamination ◽  
In Vitro Susceptibility

scholarly journals Helicobacter pylori Uptake and Efflux: Basis for Intrinsic Susceptibility to Antibiotics In Vitro

2000 ◽  
Vol 44 (2) ◽  
pp. 248-254 ◽  
Author(s):  
J. E. Bina ◽  
R. A. Alm ◽  
M. Uria-Nickelsen ◽  
S. R. Thomas ◽  
T. J. Trust ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Outer Membrane ◽  
Polymyxin B ◽  
Intrinsic Resistance ◽  
In Vitro Susceptibility ◽  
E Coli ◽  
Uptake Pathway ◽  
H Pylori

ABSTRACT We previously demonstrated (M. M. Exner, P. Doig, T. J. Trust, and R. E. W. Hancock, Infect. Immun. 63:1567–1572, 1995) that Helicobacter pylori has at least one nonspecific porin, HopE, which has a low abundance in the outer membrane but forms large channels. H. pylori is relatively susceptible to most antimicrobial agents but less susceptible to the polycationic antibiotic polymyxin B. We demonstrate here that H. pylori is able to take up higher basal levels of the hydrophobic fluorescent probe 1-N-phenylnaphthylamine (NPN) thanPseudomonas aeruginosa or Escherichia coli, consistent with its enhanced susceptibility to hydrophobic agents. Addition of polymyxin B led to a further increase in NPN uptake, indicative of a self-promoted uptake pathway, but it required a much higher amount of polymyxin B to yield a 50% increase in NPN uptake inH. pylori (6 to 8 μg/ml) than in P. aeruginosa or E. coli (0.3 to 0.5 μg/ml), suggesting that H. pylori has a less efficient self-promoted uptake pathway. Since intrinsic resistance involves the collaboration of restricted outer membrane permeability and secondary defense mechanisms, such as periplasmic β-lactamase (which H. pylori lacks) or efflux, we examined the possible role of efflux in antibiotic susceptibility. We had previously identified in H. pylori 11637 the presence of portions of three genes with homology to potential restriction-nodulation-division (RND) efflux systems. It was confirmed that H. pylori contained only these three putative RND efflux systems, named here hefABC, hefDEF, andhefGHI, and that the hefGHI system was expressed only in vivo while the two other RND systems were expressed both in vivo and in vitro. In uptake studies, there was no observable energy-dependent tetracycline, chloramphenicol, or NPN efflux activity in H. pylori. Independent mutagenesis of the three putative RND efflux operons in the chromosome of H. pylori had no effect on the in vitro susceptibility of H. pylori to 19 antibiotics. These results, in contrast to what is observed inE. coli, P. aeruginosa, and other clinically important gram-negative bacteria, suggest that active efflux does not play a role in the intrinsic resistance of H. pylori to antibiotics.

scholarly journals Percutaneous Intracavitary Antifungals for a Patient with Pulmonary Aspergilloma; with a Special Reference to in vivo Efficacies and in vitro Susceptibility Results.

1995 ◽  
Vol 34 (2) ◽  
pp. 85-88 ◽  
Author(s):  
Taeko ITOH ◽  
Hiroshi YAMADA ◽  
Akihiko YAMAGUCHI ◽  
Nakaaki KAWAMATA ◽  
Masafumi KAKEI ◽  
...  
Keyword(s):  
Special Reference ◽  
In Vitro Susceptibility ◽  
Pulmonary Aspergilloma

Enhanced fitness of a Helicobacter pylori babA mutant in a murine model

2021 ◽  
Author(s):  
M. Lorena Harvey ◽  
Aung Soe Lin ◽  
Lili Sun ◽  
Tatsuki Koyama ◽  
Jennifer H. B. Shuman ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Outer Membrane Proteins ◽  
Population Diversity ◽  
Fitness Advantage ◽  
Neutral Locus ◽  
Mutant Strains ◽  
Bacterial Fitness ◽  
H Pylori

Helicobacter pylori genomes encode >60 predicted outer membrane proteins (OMPs). Several OMPs in the Hop family act as adhesins, but the functions of most Hop proteins are unknown. To identify hop mutant strains that exhibit altered fitness in vivo compared to fitness in vitro , we used a genetic barcoding method that allowed us to track changes in the proportional abundance of H. pylori strains within a mixed population. We generated a library of hop mutant strains, each containing a unique nucleotide barcode, as well as a library of control strains, each containing a nucleotide barcode in an intergenic region predicted to be a neutral locus unrelated to bacterial fitness. We orogastrically inoculated each of the libraries into mice and analyzed compositional changes in the populations over time in vivo compared to changes detected in the populations during library passage in vitro . The control library proliferated as a relatively stable community in vitro, but there was a reduction in the population diversity of this library in vivo and marked variation in the dominant strains recovered from individual animals, consistent with the existence of a non-selective bottleneck in vivo . We did not identify any OMP mutants exhibiting fitness defects exclusively in vivo without corresponding fitness defects in vitro . Conversely, a babA mutant exhibited a strong fitness advantage in vivo but not in vitro . These findings, when taken together with results of other studies, suggest that production of BabA may have differential effects on H. pylori fitness depending on the environmental conditions.

scholarly journals Atypical clinical and laboratory features of fish-tank granuloma: A case report

2018 ◽  
Vol 6 ◽  
pp. 2050313X1880407 ◽  
Author(s):  
Michael Sander ◽  
Judith L Isaac-Renton ◽  
Megan A Sander
Keyword(s):  
Case Report ◽  
Susceptibility Testing ◽  
Mycobacterium Marinum ◽  
In Vitro Susceptibility ◽  
Laboratory Features ◽  
In Vitro Susceptibility Testing ◽  
Fish Tank ◽  
Fish Tank Granuloma

We report a case of cutaneous Mycobacterium marinum infection with the unusual reported features of pruritus and paresthesia. In addition, we report a lack of in-vivo response to antibiotics based on in-vitro susceptibility testing.

scholarly journals In vitro susceptibility of Helicobacter pylori to protolichesterinic acid from the lichen Cetraria islandica.

1997 ◽  
Vol 41 (1) ◽  
pp. 215-217 ◽  
Author(s):  
K Ingolfsdottir ◽  
M A Hjalmarsdottir ◽  
A Sigurdsson ◽  
G A Gudjonsdottir ◽  
A Brynjolfsdottir ◽  
...  
Keyword(s):  
Duodenal Ulcer ◽  
Helicobacter Pylori ◽  
Plant Extracts ◽  
Active Component ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Salt Form ◽  
Traditional Use ◽  
In Vitro Susceptibility

With reference to the traditional use of Cetraria islandica (Iceland moss) for relief of gastric and duodenal ulcer, plant extracts were screened for in vitro activity against Helicobacter pylori. (+)-Protolichesterinic acid, an aliphatic alpha-methylene-gamma-lactone, was identified as an active component. The MIC range of protolichesterinic acid, in free as well as salt form, was 16 to 64 micrograms/ml.

scholarly journals Lactobacillus johnsonii La1 Attenuates Helicobacter pylori-Associated Gastritis and Reduces Levels of Proinflammatory Chemokines in C57BL/6 Mice

2005 ◽  
Vol 12 (12) ◽  
pp. 1378-1386 ◽  
Author(s):  
Dionyssios N. Sgouras ◽  
Effrosini G. Panayotopoulou ◽  
Beatriz Martinez-Gonzalez ◽  
Kalliopi Petraki ◽  
Spyros Michopoulos ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Lamina Propria ◽  
Serum Levels ◽  
Favorable Effect ◽  
Lactobacillus Johnsonii ◽  
Ags Cells ◽  
Inflammatory Infiltration ◽  
H Pylori

ABSTRACT In clinical settings, Lactobacillus johnsonii La1 administration has been reported to have a favorable effect on Helicobacter pylori-associated gastritis, although the mechanism remains unclear. We administered, continuously through the water supply, live La1 to H. pylori-infected C57BL/6 mice and followed colonization, the development of H. pylori-associated gastritis in the lamina propria, and the levels of proinflammatory chemokines macrophage inflammatory protein 2 (MIP-2) and keratinocyte-derived cytokine (KC) in the serum and gastric tissue over a period of 3 months. We documented a significant attenuation in both lymphocytic (P = 0.038) and neutrophilic (P = 0.003) inflammatory infiltration in the lamina propria as well as in the circulating levels of anti-H. pylori immunoglobulin G antibodies (P = 0.003), although we did not observe a suppressive effect of La1 on H. pylori colonizing numbers. Other lactobacilli, such as L. amylovorus DCE 471 and L. acidophilus IBB 801, did not attenuate H. pylori-associated gastritis to the same extent. MIP-2 serum levels were distinctly reduced during the early stages of H. pylori infection in the La1-treated animals, as were gastric mucosal levels of MIP-2 and KC. Finally, we also observed a significant reduction (P = 0.046) in H. pylori-induced interleukin-8 secretion by human adenocarcinoma AGS cells in vitro in the presence of neutralized (pH 6.8) La1 spent culture supernatants, without concomitant loss of H. pylori viability. These observations suggest that during the early infection stages, administration of La1 can attenuate H. pylori-induced gastritis in vivo, possibly by reducing proinflammatory chemotactic signals responsible for the recruitment of lymphocytes and neutrophils in the lamina propria.

scholarly journals 2562. Re-Appraisal of Aminoglycoside (AG) Susceptibility Testing Breakpoints Based on the Application of Pharmacokinetics–Pharmacodynamics (PK-PD) and Contemporary Microbiology Surveillance Data

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S71-S71 ◽  
Author(s):  
Sujata M Bhavnani ◽  
Nikolas J Onufrak ◽  
Jeffrey P Hammel ◽  
David R Andes ◽  
John S Bradley ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Surveillance Data ◽  
Simulated Patients ◽  
High Dose ◽  
Target Attainment ◽  
In Vitro Susceptibility ◽  
Population Pk ◽  
Dosing Regimens

Abstract Background Resistance to AGs and numerous other classes continues to emerge. To ensure that susceptibility is accurately characterized and that clinicians have reliable data to select effective agents, appropriate in vitro susceptibility testing interpretive criteria (susceptible breakpoints [BKPTs]) are crucial to ensure optimal patient care. Recently, USCAST, the USA voice to EUCAST/EMA, evaluated the BKPTs for the 3 most commonly used AGs, gentamicin, tobramycin, and amikacin [Bhavnani et al., IDWeek 2016; P-1977]. As a result of consultation from interested parties, which included evaluating AG dosing regimens provided in the US-FDA product package inserts and simulated patients with varying creatinine clearance, these BKPTS were reassessed. Methods Data sources considered included longitudinal US reference MIC distributions using in vitro surveillance data collected over 18 years, QC performance (MIC, disk diffusion), population pharmacokinetics (PK), and in vivo PK-PD models. Using population PK models, PK-PD targets for efficacy and Monte Carlo simulation, percent probabilities of PK-PD target attainment by MIC after administration of traditional and extended interval AG dosing regimens were evaluated among simulated patients. Epidemiological cut-off and PK-PD BKPTs were considered when recommending BKPTs for AG–pathogen pairs. Results An example of PK-PD target attainment analysis output is provided in Figure 1 and a subset of recommended AG BKPTs for 3 pathogens is shown in Table 1. Updated USCAST BKPTs, which were based on the application of population PK and PK-PD models, simulation techniques, and contemporary MIC distribution statistics, are generally lower than those of EUCAST/EMA, USA-FDA, and CLSI. Adequate PK-PD target attainment was not achieved for some AG-pathogen pairs, even when high-dose AG dosing regimens and PK-PD targets for stasis were evaluated (e.g., gentamicin vs. P. aeruginosa; amikacin vs. S. aureus). Conclusion These revised AG BKPT recommendations, which will be made freely available to EUCAST, USA-FDA, and CLSI, will be finalized after considering comments from additional interested stakeholders. This process will be followed in an effort to bring harmonization to global BKPTs for AGs. Disclosures All authors: No reported disclosures.

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