scholarly journals Aminoglycoside Resistance in Mycobacterium kansasii,Mycobacterium avium-M. intracellulare, andMycobacterium fortuitum: Are Aminoglycoside-Modifying Enzymes Responsible?

2000 ◽  
Vol 44 (1) ◽  
pp. 39-42 ◽  
Author(s):  
I. I. Y. Ho ◽  
C. Y. Chan ◽  
A. F. B. Cheng
Keyword(s):  
Mycobacterium Avium ◽  
Substrate Affinity ◽  
Mycobacterium Kansasii ◽  
Mycobacterial Species ◽  
Aminoglycoside Resistance ◽  
Resistance Level ◽  
Positive Correlation ◽  
Aminoglycoside Phosphotransferase ◽  
Drug Modification

ABSTRACT Aminoglycoside acetyltransferase was detected inMycobacterium kansasii and M. fortuitum but not in M. avium-M. intracellulare when they were screened by a radioassay. Aminoglycoside phosphotransferase and nucleotidyltransferase activities were absent from all three species tested. Acetyltransferases from both M. kansasiiand M. fortuitum displayed relatively highKm s, all at the millimolar level, for substrates including tobramycin, neomycin, and kanamycin A. TheKm of each substrate was well above the corresponding maximum achievable level in serum. The low affinities of these enzymes for their substrates suggested that drug modification in vivo was very unlikely. Among the various substrates tested, no apparent positive correlation was found between substrate affinity and resistance level. The presence of aminoglycoside-modifying enzymes in these mycobacterial species was therefore not shown to confer resistance to aminoglycosides.

scholarly journals A Conserved Docking Site Modulates Substrate Affinity for Calcineurin, Signaling Output, and In Vivo Function

2007 ◽  
Vol 25 (6) ◽  
pp. 889-901 ◽  
Author(s):  
Jagoree Roy ◽  
Huiming Li ◽  
Patrick G. Hogan ◽  
Martha S. Cyert
Keyword(s):  
Substrate Affinity ◽  
Docking Site ◽  
Calcineurin Signaling

scholarly journals Effect of Fermented Feed on the Microbial Population of the Gastrointestinal Tracts of Pigs

2001 ◽  
Vol 67 (7) ◽  
pp. 3071-3076 ◽  
Author(s):  
Ren� L. van Winsen ◽  
Bert A. P. Urlings ◽  
Len J. A. Lipman ◽  
Jos M. A. Snijders ◽  
David Keuzenkamp ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Significant Positive Correlation ◽  
Stomach Contents ◽  
Significant Negative Correlation ◽  
Inhibitory Effect ◽  
Positive Correlation ◽  
Fermented Feed ◽  
The Family ◽  
Colon And Rectum

ABSTRACT An in vivo experiment was performed with pigs to study the inhibitory effect of fermented feed on the bacterial population of the gastrointestinal tract. Results demonstrated a significant positive correlation between pH and lactobacilli in the stomach contents of pigs in dry feed as well as in the stomach contents of pigs fed fermented feed. Furthermore, a significant positive correlation between the pH and the numbers of bacteria in the familyEnterobacteriaceae in the contents of the stomach of pigs fed dry feed was found. In the stomach contents of pigs fed fermented feed, a significant negative correlation was found between the concentration of the undissociated form of lactic acid and the numbers of Enterobacteriaceae. The numbers ofEnterobacteriaceae in the contents of the stomach, ileum, cecum, colon, and rectum of pigs fed fermented feed were significantly lower compared with the contents of the stomach, ileum, caecum, colon, and rectum of pigs fed dry feed. The numbers of total lactobacilli were significantly higher in the stomach contents of pigs fed fermented feed and in the ileum contents of one pig group fed fermented feed compared with the contents of pigs fed dry feed. However, the influence of lactobacilli on numbers of Enterobacteriaceae could not be demonstrated. It was concluded that fermented feed influences the bacterial ecology of the gastrointestinal tract and reduces the levels of Enterobacteriaceae in the different parts of the gastrointestinal tract.

Primary isolation of Mycobacterium avium complex-serotype 6 on blood agar

1976 ◽  
Vol 4 (3) ◽  
pp. 266-269
Author(s):  
J E Thigpen ◽  
V L Thierry ◽  
B N Gupta
Keyword(s):  
Mycobacterium Avium ◽  
Mycobacterium Avium Complex ◽  
Animal Species ◽  
Brilliant Green ◽  
Blood Agar ◽  
Mycobacterial Species ◽  
Isolation And Identification ◽  
Primary Isolation ◽  
American Opossum ◽  
Heart Blood

Mycobacterium avium complex-serotype 6 was isolated in pure culture on blood agar plates from inocula taken from the heart blood, lungs, liver, kidneys, and spleen of a naturally infected captive female opossum (Didelphis marsupialis virginiana). Repeat cultures from stored tissues and transfer of colonies from original blood agar plates revealed that the mycobacterium grew on tryptose, brilliant green, eosin-methylene blue. Sabouraud glucose, and mycobiotic agar plates and in Fletcher leptospira medium. The cultural, biochemical, and serological characteristics of the test isolate were compared with other mycobacteria. This is the first report to describe the primary isolation of a serotype from the M. avium complex from an animal species on blood agar or in Fletcher broth. In addition, this is the second documented report describing the isolation and identification of a mycobacterial species from the American opossum.

scholarly journals Effective Treatment of Mycobacterium avium subsp. hominissuis and Mycobacterium abscessus Species Infections in Macrophages, Biofilm, and Mice by Using Liposomal Ciprofloxacin

2018 ◽  
Vol 62 (10) ◽  
Author(s):  
James D. Blanchard ◽  
Valerie Elias ◽  
David Cipolla ◽  
Igor Gonda ◽  
Luiz E. Bermudez
Keyword(s):  
Effective Treatment ◽  
Mouse Models ◽  
Mycobacterium Avium ◽  
Nontuberculous Mycobacteria ◽  
Mycobacterium Abscessus ◽  
Content Type ◽  
Number Of Individuals ◽  
Intranasal Instillation

ABSTRACT Nontuberculous mycobacteria (NTM) affect an increasing number of individuals worldwide. Infection with these organisms is more common in patients with chronic lung conditions, and treatment is challenging. Quinolones, such as ciprofloxacin, have been used to treat patients, but the results have not been encouraging. In this report, we evaluate novel formulations of liposome-encapsulated ciprofloxacin (liposomal ciprofloxacin) in vitro and in vivo. Its efficacy against Mycobacterium avium and Mycobacterium abscessus was examined in macrophages, in biofilms, and in vivo using intranasal instillation mouse models. Liposomal ciprofloxacin was significantly more active than free ciprofloxacin against both pathogens in macrophages and biofilms. When evaluated in vivo, treatment with the liposomal ciprofloxacin formulations was associated with significant decreases in the bacterial loads in the lungs of animals infected with M. avium and M. abscessus. In summary, topical delivery of liposomal ciprofloxacin in the lung at concentrations greater than those achieved in the serum can be effective in the treatment of NTM, and further evaluation is warranted.

scholarly journals Non-invasive Clinical Measurement of Ocular Rigidity and Comparison to Biomechanical and Morphological Parameters in Glaucomatous and Healthy Subjects

2021 ◽  
Vol 8 ◽  
Author(s):  
Yanhui Ma ◽  
Sayoko E. Moroi ◽  
Cynthia J. Roberts
Keyword(s):  
Healthy Subjects ◽  
High Speed ◽  
Morphological Characteristics ◽  
Volume Ratio ◽  
Pulse Amplitude ◽  
Morphological Characterization ◽  
Dynamic Contour Tonometry ◽  
Stiffness Parameter ◽  
Positive Correlation

Purpose: To assess ocular rigidity using dynamic optical coherence tomography (OCT) videos in glaucomatous and healthy subjects, and to evaluate how ocular rigidity correlates with biomechanical and morphological characteristics of the human eye.Methods: Ocular rigidity was calculated using Friedenwald's empirical equation which estimates the change in intraocular pressure (IOP) produced by volumetric changes of the eye due to choroidal pulsations with each heartbeat. High-speed OCT video was utilized to non-invasively measure changes in choroidal volume through time-series analysis. A control-case study design was based on 23 healthy controls and 6 glaucoma cases. Multiple diagnostic modalities were performed during the same visit including Spectralis OCT for nerve head video, Pascal Dynamic Contour Tonometry for IOP and ocular pulse amplitude (OPA) measurement, Corvis ST for measuring dynamic biomechanical response, and Pentacam for morphological characterization.Results: Combining glaucoma and healthy cohorts (n = 29), there were negative correlations between ocular rigidity and axial length (Pearson R = −0.53, p = 0.003), and between ocular rigidity and anterior chamber volume (R = −0.64, p = 0.0002). There was a stronger positive correlation of ocular rigidity and scleral stiffness (i.e., stiffness parameter at the highest concavity [SP-HC]) (R = 0.62, p = 0.0005) compared to ocular rigidity and corneal stiffness (i.e., stiffness parameter at the first applanation [SP-A1]) (R = 0.41, p = 0.033). In addition, there was a positive correlation between ocular rigidity and the static pressure-volume ratio (P/V ratio) (R = 0.72, p < 0.0001).Conclusions: Ocular rigidity was non-invasively assessed using OCT video and OPA in a clinic setting. The significant correlation of ocular rigidity with biomechanical parameters, SP-HC and P/V ratio, demonstrated the validity of the ocular rigidity measurement. Ocular rigidity is driven to a greater extent by scleral stiffness than corneal stiffness. These in vivo methods offer an important approach to investigate the role of ocular biomechanics in glaucoma.

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