Selective infection of maize roots by streptomycin-resistant Azospirillum lipoferum and other bacteria

1979 ◽  
Vol 25 (11) ◽  
pp. 1264-1269 ◽  
Author(s):  
Johanna Döbereiner ◽  
Vera Lucia Divan Baldani
Keyword(s):  
Antibiotic Resistance ◽  
Rhizosphere Soil ◽  
Resistant Bacteria ◽  
Root Infection ◽  
Azospirillum Lipoferum ◽  
Wheat Roots ◽  
Low Level ◽  
Maize Roots ◽  
Resistant Strains

The percentage of low-level streptomycin-resistant (20 μg/mL) bacteria in surface-sterilized or washed maize roots was more than a thousand times higher than that in soil populations. There was also a higher incidence of resistant bacteria in rhizosphere as compared with non-rhizosphere soil and bacteria isolated from maize roots were relatively tolerant to several other antibiotics. Azospirillum lipoferum was predominant in surface-sterilized roots of field-grown maize and was low-level streptomycin-resistant while most soil isolates were sensitive. Inoculation with A. brasilense isolated from wheat roots was unsuccessful in terms of establishment even when streptomycin-resistant strains were used. Unidentified causes of specific plant–bacteria affinities therefore transcend the role of antibiotic resistance in maize root infection.

scholarly journals Thinking Outside the Bug: Molecular Targets and Strategies to Overcome Antibiotic Resistance

2019 ◽  
Vol 20 (6) ◽  
pp. 1255 ◽  
Author(s):  
Ana Monserrat-Martinez ◽  
Yann Gambin ◽  
Emma Sierecki
Keyword(s):  
Antibiotic Resistance ◽  
Bacterial Infections ◽  
Rational Design ◽  
Disease Onset ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
New Antibiotics ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
Antibiotic Discovery

Since their discovery in the early 20th century, antibiotics have been used as the primary weapon against bacterial infections. Due to their prophylactic effect, they are also used as part of the cocktail of drugs given to treat complex diseases such as cancer or during surgery, in order to prevent infection. This has resulted in a decrease of mortality from infectious diseases and an increase in life expectancy in the last 100 years. However, as a consequence of administering antibiotics broadly to the population and sometimes misusing them, antibiotic-resistant bacteria have appeared. The emergence of resistant strains is a global health threat to humanity. Highly-resistant bacteria like Staphylococcus aureus (methicillin-resistant) or Enterococcus faecium (vancomycin-resistant) have led to complications in intensive care units, increasing medical costs and putting patient lives at risk. The appearance of these resistant strains together with the difficulty in finding new antimicrobials has alarmed the scientific community. Most of the strategies currently employed to develop new antibiotics point towards novel approaches for drug design based on prodrugs or rational design of new molecules. However, targeting crucial bacterial processes by these means will keep creating evolutionary pressure towards drug resistance. In this review, we discuss antibiotic resistance and new options for antibiotic discovery, focusing in particular on new alternatives aiming to disarm the bacteria or empower the host to avoid disease onset.

scholarly journals Antibiotic Resistance of Gram-Negative Bacteria from Wild Captured Loggerhead Sea Turtles

Antibiotics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 162 ◽  
Author(s):  
Monica Francesca Blasi ◽  
Luciana Migliore ◽  
Daniela Mattei ◽  
Alice Rotini ◽  
Maria Cristina Thaller ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Sea Turtles ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Marine Animals ◽  
Loggerhead Sea Turtles ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Marine Habitats ◽  
Resistant Strains

Sea turtles have been proposed as health indicators of marine habitats and carriers of antibiotic-resistant bacterial strains, for their longevity and migratory lifestyle. Up to now, a few studies evaluated the antibacterial resistant flora of Mediterranean loggerhead sea turtles (Caretta caretta) and most of them were carried out on stranded or recovered animals. In this study, the isolation and the antibiotic resistance profile of 90 Gram negative bacteria from cloacal swabs of 33 Mediterranean wild captured loggerhead sea turtles are described. Among sea turtles found in their foraging sites, 23 were in good health and 10 needed recovery for different health problems (hereafter named weak). Isolated cloacal bacteria belonged mainly to Enterobacteriaceae (59%), Shewanellaceae (31%) and Vibrionaceae families (5%). Although slight differences in the bacterial composition, healthy and weak sea turtles shared antibiotic-resistant strains. In total, 74 strains were endowed with one or multi resistance (up to five different drugs) phenotypes, mainly towards ampicillin (~70%) or sulfamethoxazole/trimethoprim (more than 30%). Hence, our results confirmed the presence of antibiotic-resistant strains also in healthy marine animals and the role of the loggerhead sea turtles in spreading antibiotic-resistant bacteria.

scholarly journals What is the role of the environment in the emergence of novel antibiotic resistance genes? – A modelling approach

2021 ◽  
Author(s):  
Johan Bengtsson-Palme ◽  
Viktor Jonsson ◽  
Stefanie Heß
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Quantitative Data ◽  
Antibiotic Resistance Gene ◽  
Antibiotic Resistance Genes ◽  
Resistant Bacteria ◽  
Minor Role ◽  
Model Framework ◽  
Animal Pathogens

AbstractIt is generally accepted that intervention strategies to curb antibiotic resistance cannot solely focus on human and veterinary medicine but must also consider environmental settings. While the environment clearly has a role in the transmission of resistant bacteria, it is less clear what role it plays in the emergence of novel types of resistance. It has been suggested that the environment constitutes an enormous recruitment ground for resistance genes to pathogens, but the extent to which this actually happens is unknown. In this study, we built a model framework for resistance emergence and used the available quantitative data on the relevant processes to identify the steps which are limiting the appearance of antibiotic resistance determinants in human or animal pathogens. We also assessed the effect of uncertainty in the available data on the model results. We found that in a majority of scenarios, the environment would only play a minor role in the emergence of novel resistance genes. However, the uncertainty around this role is enormous, highlighting an urgent need of more quantitative data to understand the role of the environment in antibiotic resistance development. Specifically, more data is most needed on the fitness costs of antibiotic resistance gene (ARG) carriage, the degree of dispersal of resistant bacteria from the environment to humans, but also the rates of mobilization and horizontal transfer of ARGs. Quantitative data on these processes is instrumental to determine which processes that should be targeted for interventions to curb development and transmission of resistance.

Global geographic trends in antimicrobial resistance: the role of international travel

2019 ◽  
Vol 26 (8) ◽  
Author(s):  
Isabel Frost ◽  
Thomas P Van Boeckel ◽  
João Pires ◽  
Jessica Craig ◽  
Ramanan Laxminarayan
Keyword(s):  
Travel Medicine ◽  
Antibiotic Use ◽  
Antibiotic Consumption ◽  
Modern Medicine ◽  
International Travel ◽  
Sexual Practices ◽  
Resistant Bacteria ◽  
Clean Water ◽  
Resistant Strains

Abstract Background Rising antimicrobial resistance (AMR) is a threat to modern medicine, and increasing international mobility facilitates the spread of AMR. Infections with resistant organisms have higher morbidity and mortality, are costlier to treat, result in longer hospital stays and place a greater burden on health systems than infections caused by susceptible organisms. Here we review the role of travel in the international dissemination of AMR and consider actions at the levels of travelers, travel medicine practitioners and policymakers that would mitigate this threat. Results Resistant pathogens do not recognize international borders; travelers to areas with high AMR prevalence are likely to be exposed to resistant bacteria and return to their home countries colonized. Medical tourists go between health facilities with drastically different rates of AMR, potentially transmitting highly resistant strains. Drug-resistant bacteria have been found in every continent; however, differences between countries in the prevalence of AMR depend on multiple factors. These include levels of antibiotic consumption (including inappropriate use), access to clean water, adequate sanitation, vaccination coverage, the availability of quality healthcare and access to high-quality medical products. Conclusions Travelers to areas with high levels of AMR should have vaccines up to date, be aware of ways of treating and preventing travelers’ diarrhea (other than antibiotic use) and be informed on safe sexual practices. The healthcare systems of low- and middle-income countries require investment to reduce the transmission of resistant strains by improving access to clean water, sanitation facilities and vaccines. Efforts are needed to curb inappropriate antibiotic use worldwide. In addition, more surveillance is needed to understand the role of the movement of humans, livestock and food products in resistance transmission. The travel medicine community has a key role to play in advocating for the recognition of AMR as a priority on the international health agenda. Key policy recommendations AMR is a threat to modern medicine, and international travel plays a key role in the spread of highly resistant strains. It is essential that this is addressed at multiple levels. Individual travelers can reduce antibiotic consumption and the likelihood of infection. Travelers should have up-to-date vaccines and be informed on methods of preventing and treating travelers’ diarrhea, other than use of antibiotics and on safe sexual practices, such as condom use. Healthcare facilities need to be aware of the travel history of patients to provide appropriate treatment to those who are at high risk of exposure and to prevent further spread. Internationally, in countries without reliable and universal access to clean water, sanitation and hygiene, investment is needed to reduce the emergence and spread of resistance and ensure the antimicrobials available are of assured quality. High-income countries must ensure their use of antimicrobials is appropriate to reduce selection for AMR. Surveillance across all countries is needed to monitor and respond to this emerging threat.

scholarly journals Resistance to antibiotics in Gram-negative bacteria isolated from broiler carcasses

2002 ◽  
Vol 54 (1) ◽  
pp. 1-7
Author(s):  
M.A.S. Moreira ◽  
C.A. Moraes
Keyword(s):  
Antibiotic Resistance ◽  
Resistant Bacteria ◽  
Processing Plant ◽  
Growth Promoter ◽  
Gram Negative Bacteria ◽  
Beta Lactams ◽  
Gram Negative ◽  
Low Levels

One hundred and ninety-seven isolates of Gram-negative bacteria, comprising 10 genera, were isolated from poultry carcasses at a processing plant in order to investigate resistance to low levels of antibiotics. The samples were taken just after evisceration and before inspection. Most of the isolates were of Samonella and Escherichia. Other genera present were Enterobacter, Serratia, Klebsiella, Kluyvera, Erwinia, Citrobacter, Pseudomonas and Aeromonas. Distinct profiles of antibiotic resistance were detected. Resistance to more than two antibiotics predominated and spanned several classes of antibiotics. Salmonellae and escherichiae were mainly resistant to the aminoglycosides, followed by tetracycline, nitrofuran, sulpha, macrolide, chloramphenicol, quinolones and beta-lactams. Most isolates were sensitive to 30mug/ml olaquindox, the growth promoter in use at the time of sampling. However, many were resistant to a level of 10mug/ml and 13mug/ml olaquindox, levels present in the gut due to the dilution in the feed. The results suggest a possible role of low level administration of antibiotics to broilers in selecting multi-resistant bacteria in vivo.

scholarly journals Assessment of Bacterial Antibiotic Resistance Transfer in the Gut

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Susanne Schjørring ◽  
Karen A. Krogfelt
Keyword(s):  
Antibiotic Resistance ◽  
Gene Transfer ◽  
Resistance Genes ◽  
Bacterial Flora ◽  
Antibiotic Resistance Genes ◽  
Resistant Bacteria ◽  
Gi Tract ◽  
Antibiotic Resistant ◽  
Multiresistant Bacteria ◽  
Resistant Strains

We assessed horizontal gene transfer between bacteria in the gastrointestinal (GI) tract. During the last decades, the emergence of antibiotic resistant strains and treatment failures of bacterial infections have increased the public awareness of antibiotic usage. The use of broad spectrum antibiotics creates a selective pressure on the bacterial flora, thus increasing the emergence of multiresistant bacteria, which results in a vicious circle of treatments and emergence of new antibiotic resistant bacteria. The human gastrointestinal tract is a massive reservoir of bacteria with a potential for both receiving and transferring antibiotic resistance genes. The increased use of fermented food products and probiotics, as food supplements and health promoting products containing massive amounts of bacteria acting as either donors and/or recipients of antibiotic resistance genes in the human GI tract, also contributes to the emergence of antibiotic resistant strains. This paper deals with the assessment of antibiotic resistance gene transfer occurring in the gut.

scholarly journals Low-Level Tolerance to Antibiotic Trimethoprim in QAC-Adapted Subpopulations of Listeria monocytogenes

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1800
Author(s):  
Divya Kode ◽  
Ramakrishna Nannapaneni ◽  
Sam Chang
Keyword(s):  
Antibiotic Resistance ◽  
Listeria Monocytogenes ◽  
Food Chain ◽  
Food Processing ◽  
Resistant Bacteria ◽  
Continuous Exposure ◽  
Antibiotic Resistant ◽  
Low Level ◽  
Sublethal Doses ◽  
Sublethal Concentrations

Between January and July 2021, there were as many as 30 recalls in the U.S. due to potential Listeria monocytogenes contamination from a variety of food products including muffins, kimchi, chicken salad, ready-to-eat chicken, smoked fish, mushrooms, queso fresco cheese, ice cream, turkey sandwiches, squash, and other foods. A contaminated food chain can serve as a potential vehicle for transmitting antibiotic resistant bacteria since there is a slow emergence of multi-drug antibiotic resistance in L. monocytogenes. Biocides are essential for safe food processing, but they may also induce unintended selective pressure at sublethal doses for the expression of antibiotic resistance in L. monocytogenes. To better understand the sources of such slow emergence of antibiotic resistance through biocide residues present in the food environments, we are working on the role of sublethal doses of commonly used biocides in defined broth and water models for understanding L. monocytogenes adaptation. We recently published the development of low-level tolerance to fluoroquinolone antibiotic ciprofloxacin in quaternary ammonium compound (QAC) adapted subpopulations of L. monocytogenes (Microorganisms 9, 1052). Of the six different antibiotics tested to determine heterologous stress adaptation in eight strains of L. monocytogenes, trimethoprim was the second one that exhibited low-level tolerance development after continuous exposure (by three approaches) to sublethal concentrations of QAC against actively growing planktonic cells of L. monocytogenes. When adapted to daily cycles of fixed or gradually increasing sublethal concentrations of QAC, we observed three main findings in eight L. monocytogenes strains against trimethoprim: (a) 3 of the 8 strains exhibited significant increase in short-range minimum inhibitory concentration (MIC) of trimethoprim by 1.7 to 2.5 fold in QAC-adapted subpopulations compared to non-adapted cells (p < 0.05); (b) 2 of the 8 strains exhibited significant increase in growth rate in trimethoprim (optical density (OD) by 600 nm at 12 h) by 1.4 to 4.8 fold in QAC-adapted subpopulations compared to non-adapted cells (p < 0.05); and (c) 5 of the 8 strains yielded significantly higher survival by 1.3-to-3.1 log CFU/mL in trimethoprim in QAC-adapted subpopulations compared to the non-adapted control (p < 0.05). However, for 3/8 strains of L. monocytogenes, there was no increase in the survival of QAC-adapted subpopulations compared to non-adapted control in trimethoprim. These findings suggest the potential formation of low-level trimethoprim tolerant subpopulations in some L. monocytogenes strains where QAC may be used widely. These experimental models are useful in developing early detection methods for tracking the slow emergence of antibiotic tolerant strains through food chain. Also, these findings are useful in understanding the predisposing conditions leading to slow emergence of antibiotic resistant strains of L. monocytogenes in various food production and food processing environments.

scholarly journals EXTRACELLULAR POLYMERIC SUBSTANCE OF BIOFILMS IN THE FORMATION OF ANTIMICROBIAL RESISTANCE OF MICROORGANISMS

2019 ◽  
pp. 6-12
Author(s):  
Olexandra Kovalenko ◽  
Yaroslav Kizim ◽  
Natalia Voroshylova
Keyword(s):  
Antibiotic Resistance ◽  
Antimicrobial Resistance ◽  
Building Material ◽  
Extracellular Polymeric Substance ◽  
Modern Literature ◽  
Main Form ◽  
Polymeric Substance ◽  
Resistant Strains ◽  
Permanent Formation

Abstract. The analysis of modern literature data on the mechanisms of the formation of antibiotic resistance and the role of extracellular polymeric substance in biofilms, which are the main form of microbial existence. The role of extracellular polymeric substance in limiting of the effect of unfavorable factors as well as the regularity and necessity of its formation for the community of microorganisms were discussed. The position on the permanent character of phenotype dispersion of microorganisms is postulated. This dispersion doesn’t provide the formation of more resistant strains only, but plays the prominent role in the permanent formation of various forms, that aren’t viable under given conditions but play the role of a depot of building material for extracellular polymeric substance. The mass death of low-resistant forms caused by the action of the antibiotic ensures saturation of the extracellular polymeric substance by dechromatized DNA, that increases the resistance of the microbial socium and contributes to the further formation of multiresistance.

scholarly journals Helicobacter pylori antibiotic resistance and [13C]urea breath test values

2010 ◽  
Vol 59 (5) ◽  
pp. 588-591 ◽  
Author(s):  
Vincenzo De Francesco ◽  
Angelo Zullo ◽  
Federico Perna ◽  
Floriana Giorgio ◽  
Cesare Hassan ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antibiotic Resistance ◽  
Breath Test ◽  
Multidrug Resistant ◽  
Urea Breath Test ◽  
Predictive Role ◽  
Resistant Strains ◽  
13C Urea Breath Test ◽  
H Pylori

A correlation between δ over baseline (DOB) values of the [13C]urea breath test (UBT) and Helicobacter pylori clarithromycin resistance has been reported, suggesting a possible predictive role of UBT in therapeutic outcome. However, available data are limited and conflicting. This study aimed to clarify this issue, assessing the possible relationship between H. pylori resistance towards different antibiotics (clarithromycin, metronidazole and levofloxacin) and UBT values. The data showed similar DOB values between susceptible and resistant strains for clarithromycin (46.9±32.3 vs 45.7±30.6; P=0.8), metronidazole (46.4±29.6 vs 47.4±37.9; P=0.8), and levofloxacin (45.0±30.2 vs 54.2±38.4; P=0.08). Likewise, comparable DOB values were observed between susceptible and multidrug-resistant strains (45.4±29.6 vs 54.8±44.8; P=0.1). In conclusion, our data failed to find a significant correlation between UBT values and H. pylori antibiotic resistance.

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