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Author

Ivan Mitov

Other affiliations: Max Planck Society
Bio: Ivan Mitov is an academic researcher from Sofia Medical University. The author has contributed to research in topics: Helicobacter pylori & Clarithromycin. The author has an hindex of 30, co-authored 175 publications receiving 2948 citations. Previous affiliations of Ivan Mitov include Max Planck Society.


Papers
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Journal ArticleDOI
TL;DR: Bulgarian propolis had a strong and dose-dependent activity against most of the H. pylori strains tested and the effect of propolis on H.pylori in vitro is promising, further microbiological, pharmacological and clinical trials are required.
Abstract: Propolis exhibits antimicrobial, anti-inflammatory and other biological effects. The aim of this study was to evaluate the activity of 30 % ethanolic extract of Bulgarian propolis against 94 Helicobacter pylori strains by three methods. By the agar-well diffusion method, only 13.8 % of the strains exhibited no inhibition by 30 μl propolis extract (containing 9 mg propolis) and all isolates were inhibited to some extent by 90 μl of the extract (27 mg propolis) per well. The mean diameters of growth inhibition by 30, 60 or 90 μl propolis extract or 30 μl 96 % ethanol per well were 16.8, 19.2, 27.5 and 8.3 mm, respectively. The propolis extract was more active than the ethanol (P < 0.001). With 90 μl propolis extract per well, 69.4 % of the strains exhibited large diameters of growth inhibition (⩾20 mm) versus 26.6 % with 30 μl per well (P < 0.001). With moist propolis discs, inhibition was detected in more strains (92.1 %) than with dried discs (78.2 %, P < 0.05), with mean inhibitory diameters of 18.7 and 13.8 mm, respectively. By the agar dilution method, 100 and 300 μg propolis ml−1 inhibited the growth of 57.1 % and 76.2 %, respectively, of the 21 strains tested. In conclusion, Bulgarian propolis had a strong and dose-dependent activity against most of the H. pylori strains tested. Although the effect of propolis on H. pylori in vitro is promising, further microbiological, pharmacological and clinical trials are required.

187 citations

Journal ArticleDOI
TL;DR: The present review describes the known virulence determinants of P. aeruginosa, the stages of infection as well as the importance of QS in the pathogenesis of P., and describes the two-component sensor kinases controlling the production of virulence factors aswell as the switch from acute to chronic infection.
Abstract: Pseudomonas aeruginosa is an increasingly prevalent opportunistic pathogen that causes a variety of nosocomial infections, life-threatening diseases in immunocompromised persons and chronic pulmonary infections in cystic fibrosis patients. The organism’s virulence depends on an arsenal of cell-associated and extracellular factors determining the pathogenesis of infections as multifactorial. Most P. aeruginosa infections are both invasive and toxinogenic. Many of the extracellular virulence factors (proteases, exotoxin A, pyocyanin, siderophores, hemolysins) required for tissue invasion and dissemination of P. aeruginosa are controlled by quorum sensing (QS) that enable the bacteria to produce these factors in a coordinated, cell-density-dependent manner and overwhelm the host defense mechanisms during acute infection. Sometimes, QS also contributes to biofilm formation and thus participates in pathogenesis of chronic infection. This system is recognized to be a global regulatory network controlling the expression of a large number of virulence genes either directly or indirectly. Two-component sensor kinases such as RetS, LadS and GacS are also controlling the production of virulence factors as well as the switch from acute to chronic infection. The present review describes the known virulence determinants of P. aeruginosa, the stages of infection as well as the importance of QS in the pathogenesis of P. aeruginosa infection.

117 citations

Journal ArticleDOI
TL;DR: The geographic map and evolution of primary H. pylori resistance are clinically important, should be considered when choosing eradication regimens, and should be monitored constantly at national and global levels in an attempt to reach the recently recommended goal of eradication of more than 95%.
Abstract: Antibiotic resistance in Helicobacter pylori is the major cause of eradication failure. Primary H. pylori susceptibility patterns, however, are becoming less predictable. Currently, high (> or =20%) clarithromycin resistance rates have been observed in the USA and in developed countries in Europe and Asia, while the highest (> or =80%) metronidazole-resistance rates have been reported in Africa, Asia and South America. Primary quinolone-resistance rates of 10% or more have already been reported in developed countries in Europe and Asia. Primary amoxicillin resistance has been low (0 to <2%) in Europe but higher (6-59%) in Africa, Asia and South America. Similarly, tetracycline resistance has been absent or low (<5%) in most countries and higher (9-27%) in Asia and South America. The increasing clarithromycin and quinolone resistance, and multidrug resistance detected in 0 to less than 5% in Europe and more often (14.2%) in Brazil are worrying. Growing resistance often parallels national antibiotic consumption and may vary within patient groups according to the geographic region, patient's age and sex, type of disease, birthplace, other infections and other factors. The geographic map and evolution of primary H. pylori resistance are clinically important, should be considered when choosing eradication regimens, and should be monitored constantly at national and global levels in an attempt to reach the recently recommended goal of eradication of more than 95%.

106 citations

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TL;DR: In eastern Europe, primary H. pylori resistance to metronidazole is considerable, and that to clarithromycin is similar to or slightly higher than that in western Europe.

105 citations

Journal ArticleDOI
01 Feb 2015-Anaerobe
TL;DR: The antibiotic resistance changes in the anaerobes are diverse and dynamic and regular national surveys of resistance and both anaerobic microbiology and susceptibility testing of the isolates become more and more valuable.

101 citations


Cited by
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Journal ArticleDOI
01 Jan 2017-Gut
TL;DR: This fifth edition of the Maastricht Consensus Report describes how experts from 24 countries examined new data related to H. pylori infection in the various clinical scenarios and provided recommendations on the basis of the best available evidence and relevance.
Abstract: Important progress has been made in the management of Helicobacter pylori infection and in this fifth edition of the Maastricht Consensus Report, key aspects related to the clinical role of H. pylori were re-evaluated in 2015. In the Maastricht V/Florence Consensus Conference, 43 experts from 24 countries examined new data related to H. pylori in five subdivided workshops: (1) Indications/Associations, (2) Diagnosis, (3) Treatment, (4) Prevention/Public Health, (5) H. pylori and the Gastric Microbiota. The results of the individual workshops were presented to a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in the various clinical scenarios.

2,219 citations

Journal ArticleDOI
TL;DR: Overall, campylobacteriosis is still one of the most important infectious diseases that is likely to challenge global health in the years to come.
Abstract: Campylobacter jejuni infection is one of the most widespread infectious diseases of the last century. The incidence and prevalence of campylobacteriosis have increased in both developed and developing countries over the last 10 years. The dramatic increase in North America, Europe, and Australia is alarming, and data from parts of Africa, Asia, and the Middle East indicate that campylobacteriosis is endemic in these areas, especially in children. In addition to C. jejuni, there is increasing recognition of the clinical importance of emerging Campylobacter species, including Campylobacter concisus and Campylobacter ureolyticus. Poultry is a major reservoir and source of transmission of campylobacteriosis to humans. Other risk factors include consumption of animal products and water, contact with animals, and international travel. Strategic implementation of multifaceted biocontrol measures to reduce the transmission of this group of pathogens is paramount for public health. Overall, campylobacteriosis is still one of the most important infectious diseases that is likely to challenge global health in the years to come. This review provides a comprehensive overview of the global epidemiology, transmission, and clinical relevance of Campylobacter infection.

987 citations

Journal ArticleDOI
TL;DR: A number of studies confirm that H. pylori prevalence is falling worldwide especially in the developed world and in children but that the level of infection is higher in certain ethnic minorities and in Migrants.
Abstract: The study of Helicobacter pylori genetic variability brought us interesting data on the history of mankind. Based on multilocus sequence typing and more recently on whole-genome sequencing, paleomicrobiology still attracts the attention of global researchers in relation to its ancestor roots and coexistence with humans. Three studies determining the prevalence of virulence factors illustrates the controversial results obtained since 30 years by studies trying to associate prevalence of different virulence markers and clinical outcomes of H. pylori infection. Three articles analyzed the prevalence and risk of multiple (genetically distinct isolates) and mixed (susceptible and resistant isolates) infections. A number of studies confirm that H. pylori prevalence is falling worldwide especially in the developed world and in children but that the level of infection is higher in certain ethnic minorities and in Migrants. There is little new in identifying the mode of H. pylori transmission though intrafamilial spread appears to be important. There have, however, been some interesting papers on the presence of the organism in food, water, and the oral cavity.

962 citations

Journal ArticleDOI
01 Sep 2004-Gut
TL;DR: The aim was to review the prevalence of H pylori resistance to these various antibiotics, their clinical importance, and methods of testing, especially in light of the resistance mechanism which allows application of molecular methods.
Abstract: The discovery that Helicobacter pylori infection is the main cause of most gastroduodenal diseases has been a major breakthrough in gastroenterology It has dramatically changed the management of these diseases which are now considered as infectious diseases and are treated with antibiotics Triple therapy, including two antibiotics, amoxicillin and clarithromycin, and a proton pump inhibitor given for a week has been recommended as the treatment of choice at several consensus conferences1–6 However, this treatment may fail for several reasons, as reported elsewhere7 In fact, the main reason for failure was found to be H pylori resistance to one of the antibiotics used (that is, clarithromycin) Other treatments have also been proposed, including metronidazole, a drug for which resistance is also a problem although to a lesser extent, as well as tetracycline, fluoroquinolones, and rifamycins for which resistance has become an emerging issue8,9 Our aim was to review the prevalence of H pylori resistance to these various antibiotics, their clinical importance, and methods of testing, especially in light of the resistance mechanism which allows application of molecular methods Numerous studies have been performed to determine the prevalence of H pylori resistance to antibiotics However, many of them have drawbacks, in particular concerning the number and representativeness of the strains tested Most of the studies were performed in specialised centres, with recruitment of special cases which are not always representative of patients as a whole and, because these studies are monocentric, the number of patients may be low, leading to wide confidence intervals of the prevalence rates obtained Ideal studies involving patients who are representative of a given region are few An alternative has been to analyse prevalence data obtained from clinical trials aiming to evaluate new regimens As prevalence is in essence an evolving phenomenon, only …

921 citations

Journal ArticleDOI
TL;DR: In just the past several years, SIgA has been identified as having the capacity to directly quench bacterial virulence factors, influence composition of the intestinal microbiota by Fab-dependent and Fab-independent mechanisms, promote retro-transport of antigens across the intestinal epithelium to dendritic cell subsets in gut-associated lymphoid tissue, and, finally, to downregulate proinflammatory responses normally associated with the uptake of highly pathogenic bacteria.

891 citations