Phenotypic changes associated with the fitness cost in antibiotic resistant Escherichia coli strains

2016 ◽  
Vol 12 (2) ◽  
pp. 414-420 ◽  
Author(s):  
Shingo Suzuki ◽  
Takaaki Horinouchi ◽  
Chikara Furusawa
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Fitness Cost ◽  
Bacterial Cells ◽  
Antibiotic Resistant ◽  
Phenotypic Changes

Background: the acquisition of antibiotic resistance in bacterial cells is often accompanied with a reduction of fitness in the absence of antibiotics, known as the “fitness cost”.

Mechanisms involved in effects of antimicrobial peptides, bactenectins ChBac3.4, ChBac5, and mini-ChBac7.5Nb, on bacterial cells

2017 ◽  
pp. 43-50
Author(s):  
О.В. Шамова ◽  
М.С. Жаркова ◽  
П.М. Копейкин ◽  
Д.С. Орлов ◽  
Е.А. Корнева
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Innate Immunity ◽  
Infectious Diseases ◽  
Metabolic Activity ◽  
Capra Hircus ◽  
Bacterial Cells ◽  
Antibiotic Resistant ◽  
Resistant Strains

Антимикробные пептиды (АМП) системы врожденного иммунитета - соединения, играющие важную роль в патогенезе инфекционных заболеваний, так как обладают свойством инактивировать широкий спектр патогенных бактерий, обеспечивая противомикробную защиту живых организмов. В настоящее время АМП рассматриваются как потенциальные соединения-корректоры инфекционной патологии, вызываемой антибиотикорезистентными бактериями (АБР). Цель данной работы состояла в изученим механизмов антибактериального действия трех пептидов, принадлежащих к семейству бактенецинов - ChBac3.4, ChBac5 и mini-ChBac7.5Nb. Эти химически синтезированные пептиды являются аналогами природных пролин-богатых АМП, обнаруженных в лейкоцитах домашней козы Capra hircus и проявляющих высокую антимикробную активность, в том числе и в отношении грамотрицательных АБР. Методы. Минимальные ингибирующие и минимальные бактерицидные концентрации пептидов (МИК и МБК) определяли методом серийных разведений в жидкой питательной среде с последующим высевом на плотную питательную среду. Эффекты пептидов на проницаемость цитоплазматической мембраны бактерий для хромогенного маркера исследовали с использованием генетически модифицированного штамма Escherichia coli ML35p. Действие бактенецинов на метаболическую активность бактерий изучали с применением маркера резазурина. Результаты. Показано, что все исследованные пептиды проявляют высокую антимикробную активность в отношении Escherichia coli ML35p и антибиотикоустойчивых штаммов Escherichia coli ESBL и Acinetobacter baumannii in vitro, но их действие на бактериальные клетки разное. Использован комплекс методик, позволяющих наблюдать в режиме реального времени динамику действия бактенецинов в различных концентрациях (включая их МИК и МБК) на барьерную функцию цитоплазматической мембраны и на интенсивность метаболизма бактериальных клеток, что дало возможность выявить различия в характере воздействия бактенецинов, отличающихся по структуре молекулы, на исследуемые микроорганизмы. Установлено, что действие каждого из трех исследованных бактенецинов в бактерицидных концентрациях отличается по эффективности нарушения целостности бактериальных мембран и в скорости подавления метаболизма клеток. Заключение. Полученная информация дополнит существующие фундаментальные представления о механизмах действия пролин-богатых пептидов врожденного иммунитета, а также послужит основой для биотехнологических исследований, направленных на разработку на базе этих соединений новых антибиотических препаратов для коррекции инфекционных заболеваний, вызываемых АБР и являющимися причинами тяжелых внутрибольничных инфекций. Antimicrobial peptides (AMPs) of the innate immunity are compounds that play an important role in pathogenesis of infectious diseases due to their ability to inactivate a broad array of pathogenic bacteria, thereby providing anti-microbial host defense. AMPs are currently considered promising compounds for treatment of infectious diseases caused by antibiotic-resistant bacteria. The aim of this study was to investigate molecular mechanisms of the antibacterial action of three peptides from the bactenecin family, ChBac3.4, ChBac5, and mini-ChBac7.5Nb. These chemically synthesized peptides are analogues of natural proline-rich AMPs previously discovered by the authors of the present study in leukocytes of the domestic goat, Capra hircus. These peptides exhibit a high antimicrobial activity, in particular, against antibiotic-resistant gram-negative bacteria. Methods. Minimum inhibitory and minimum bactericidal concentrations of the peptides (MIC and MBC) were determined using the broth microdilution assay followed by subculturing on agar plates. Effects of the AMPs on bacterial cytoplasmic membrane permeability for a chromogenic marker were explored using a genetically modified strain, Escherichia coli ML35p. The effect of bactenecins on bacterial metabolic activity was studied using a resazurin marker. Results. All the studied peptides showed a high in vitro antimicrobial activity against Escherichia coli ML35p and antibiotic-resistant strains, Escherichia coli ESBL and Acinetobacter baumannii, but differed in features of their action on bacterial cells. The used combination of techniques allowed the real-time monitoring of effects of bactenecin at different concentrations (including their MIC and MBC) on the cell membrane barrier function and metabolic activity of bacteria. The differences in effects of these three structurally different bactenecins on the studied microorganisms implied that these peptides at bactericidal concentrations differed in their capability for disintegrating bacterial cell membranes and rate of inhibiting bacterial metabolism. Conclusion. The obtained information will supplement the existing basic concepts on mechanisms involved in effects of proline-rich peptides of the innate immunity. This information will also stimulate biotechnological research aimed at development of new antibiotics for treatment of infectious diseases, such as severe in-hospital infections, caused by antibiotic-resistant strains.

scholarly journals Comparison of Antibiotic Resistance Profile of Escherichia coli between Pristine and Human-Impacted Sites in a River

Antibiotics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 575
Author(s):  
Emi Nishimura ◽  
Masateru Nishiyama ◽  
Kei Nukazawa ◽  
Yoshihiro Suzuki
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Resistant Bacteria ◽  
Downstream Site ◽  
Antibiotic Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Upstream Site ◽  
Resistance Profile ◽  
Antibiotic Resistance Profile ◽  
Significant Difference

Information on the actual existence of antibiotic-resistant bacteria in rivers where sewage, urban wastewater, and livestock wastewater do not load is essential to prevent the spread of antibiotic-resistant bacteria in water environments. This study compared the antibiotic resistance profile of Escherichia coli upstream and downstream of human habitation. The survey was conducted in the summer, winter, and spring seasons. Resistance to one or more antibiotics at upstream and downstream sites was on average 18% and 20%, respectively, and no significant difference was observed between the survey sites. The resistance rates at the upstream site (total of 98 isolated strains) to each antibiotic were cefazolin 17%, tetracycline 12%, and ampicillin 8%, in descending order. Conversely, for the downstream site (total of 89 isolated strains), the rates were ampicillin 16%, cefazolin 16%, and tetracycline 1% in descending order. The resistance rate of tetracycline in the downstream site was significantly lower than that of the upstream site. Furthermore, phylogenetic analysis revealed that many strains showed different resistance profiles even in the same cluster of the Pulsed-Field Gel Electrophoresis (PFGE) pattern. Moreover, the resistance profiles differed in the same cluster of the upstream and the downstream sites. In flowing from the upstream to the downstream site, it is plausible that E. coli transmitted or lacked the antibiotic resistance gene.

scholarly journals Mechanisms of Resistance in Multiple-Antibiotic-Resistant Escherichia coli Strains of Human, Animal, and Food Origins

2004 ◽  
Vol 48 (10) ◽  
pp. 3996-4001 ◽  
Author(s):  
Yolanda Sáenz ◽  
Laura Briñas ◽  
Elena Domínguez ◽  
Joaquim Ruiz ◽  
Myriam Zarazaga ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Amino Acid ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Mechanisms Of Resistance ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Class 1 ◽  
Human Animal

ABSTRACT Seventeen multiple-antibiotic-resistant nonpathogenic Escherichia coli strains of human, animal, and food origins showed a wide variety of antibiotic resistance genes, many of them carried by class 1 and class 2 integrons. Amino acid changes in MarR and mutations in marO were identified for 15 and 14 E. coli strains, respectively.

scholarly journals Antibiotic-resistant Escherichia coli and Salmonella spp. associated with dairy cattle and farm environment having public health significance

2019 ◽  
Vol 12 (7) ◽  
pp. 984-993 ◽  
Author(s):  
Md. Abdus Sobur ◽  
Abdullah Al Momen Sabuj ◽  
Ripon Sarker ◽  
A. M. M. Taufiqur Rahman ◽  
S. M. Lutful Kabir ◽  
...  
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
One Health ◽  
Dairy Farm ◽  
Antibiotic Resistance Genes ◽  
Salmonella Spp ◽  
Antibiotic Resistant ◽  
E Coli

Aim: The present study was carried out to determine load of total bacteria, Escherichia coli and Salmonella spp. in dairy farm and its environmental components. In addition, the antibiogram profile of the isolated bacteria having public health impact was also determined along with identification of virulence and resistance genes by polymerase chain reaction (PCR) under a one-health approach. Materials and Methods: A total of 240 samples of six types (cow dung - 15, milk - 10, milkers' hand wash - 10, soil - 10 water - 5, and vegetables - 10) were collected from four dairy farms. For enumeration, the samples were cultured onto plate count agar, eosin methylene blue, and xylose-lysine deoxycholate agar and the isolation and identification of the E. coli and Salmonella spp. were performed based on morphology, cultural, staining, and biochemical properties followed by PCR. The pathogenic strains of E. coli stx1, stx2, and rfbO157 were also identified through PCR. The isolates were subjected to antimicrobial susceptibility test against 12 commonly used antibiotics by disk diffusion method. Detection of antibiotic resistance genes ereA, tetA, tetB, and SHV were performed by PCR. Results: The mean total bacterial count, E. coli and Salmonella spp. count in the samples ranged from 4.54±0.05 to 8.65±0.06, 3.62±0.07 to 7.04±0.48, and 2.52±0.08 to 5.87±0.05 log colony-forming unit/g or ml, respectively. Out of 240 samples, 180 (75%) isolates of E. coli and 136 (56.67%) isolates of Salmonella spp. were recovered through cultural and molecular tests. Among the 180 E. coli isolates, 47 (26.11%) were found positive for the presence of all the three virulent genes, of which stx1 was the most prevalent (13.33%). Only three isolates were identified as enterohemorrhagic E. coli. Antibiotic sensitivity test revealed that both E. coli and Salmonella spp. were found highly resistant to azithromycin, tetracycline, erythromycin, oxytetracycline, and ertapenem and susceptible to gentamycin, ciprofloxacin, and imipenem. Among the four antibiotic resistance genes, the most observable was tetA (80.51-84.74%) in E. coli and Salmonella spp. and SHV genes were the lowest one (22.06-25%). Conclusion: Dairy farm and their environmental components carry antibiotic-resistant pathogenic E. coli and Salmonella spp. that are potential threat for human health which requires a one-health approach to combat the threat.

scholarly journals Increased Survival of Antibiotic-Resistant Escherichia coli inside Macrophages

2012 ◽  
Vol 57 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Migla Miskinyte ◽  
Isabel Gordo
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Bacterial Infections ◽  
Resistance Mutation ◽  
Fitness Cost ◽  
Resistance Mutations ◽  
Content Type ◽  
E Coli ◽  
Fitness Effects ◽  
K 12

ABSTRACTMutations causing antibiotic resistance usually incur a fitness cost in the absence of antibiotics. The magnitude of such costs is known to vary with the environment. Little is known about the fitness effects of antibiotic resistance mutations when bacteria confront the host's immune system. Here, we study the fitness effects of mutations in therpoB,rpsL, andgyrAgenes, which confer resistance to rifampin, streptomycin, and nalidixic acid, respectively. These antibiotics are frequently used in the treatment of bacterial infections. We measured two important fitness traits—growth rate and survival ability—of 12Escherichia coliK-12 strains, each carrying a single resistance mutation, in the presence of macrophages. Strikingly, we found that 67% of the mutants survived better than the susceptible bacteria in the intracellular niche of the phagocytic cells. In particular, allE. colistreptomycin-resistant mutants exhibited an intracellular advantage. On the other hand, 42% of the mutants incurred a high fitness cost when the bacteria were allowed to divide outside of macrophages. This study shows that single nonsynonymous changes affecting fundamental processes in the cell can contribute to prolonged survival ofE. coliin the context of an infection.

scholarly journals Monitoring of Water Quality, Antibiotic Residues, and Antibiotic-Resistant Escherichia coli in the Kshipra River in India over a 3-Year Period

2020 ◽  
Vol 17 (21) ◽  
pp. 7706
Author(s):  
Nada Hanna ◽  
Manju Purohit ◽  
Vishal Diwan ◽  
Salesh P. Chandran ◽  
Emilia Riggi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Antibiotic Resistance ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Antibiotic Residues ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Water And Sediment ◽  
Measured Water

The emergence of antibiotic resistance is a major global and environmental health issue, yet the presence of antibiotic residues and resistance in the water and sediment of a river subjected to excessive anthropogenic activities and their relationship with water quality of the river are not well studied. The objectives of the present study were a) to investigate the occurrence of antibiotic residues and antibiotic-resistant Escherichia coli (E. coli) in the water and sediment of the Kshipra river in India at seven selected sites during different seasons of the years 2014, 2015, and 2016 and b) to investigate the association between antibiotic residues and antibiotic-resistant E. coli in water and sediment and measured water quality parameters of the river. Antibiotic residues and resistant E. coli were present in the water and sediment and were associated with the measured water quality parameters. Sulfamethoxazole was the most frequently detected antibiotic in water at the highest concentration of 4.66 µg/L and was positively correlated with the water quality parameters. Significant (p < 0.05) seasonal and spatial variations of antibiotic-resistant E. coli in water and sediment were found. The resistance of E. coli to antibiotics (e.g., sulfamethiazole, norfloxacin, ciprofloxacine, cefotaxime, co-trimoxazole, ceftazidime, meropenem, ampicillin, amikacin, metronidazole, tetracycline, and tigecycline) had varying associations with the measured water and sediment quality parameters. Based on the results of this study, it is suggested that regular monitoring and surveillance of water quality, including antibiotic residues and antibiotic resistance, of all rivers should be taken up as a key priority, in national and Global Action Plans as these can have implications for the buildup of antibiotic resistance.

scholarly journals Persistence of Transferable Extended-Spectrum-β-Lactamase Resistance in the Absence of Antibiotic Pressure

2012 ◽  
Vol 56 (9) ◽  
pp. 4703-4706 ◽  
Author(s):  
Jennifer L. Cottell ◽  
Mark A. Webber ◽  
Laura J. V. Piddock
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Fitness Cost ◽  
Resistant Bacteria ◽  
Bacterial Host ◽  
Antibiotic Resistant ◽  
M 14 ◽  
Host Strains

ABSTRACTThe treatment of infections caused by antibiotic-resistant bacteria is one of the great challenges faced by clinicians in the 21st century. Antibiotic resistance genes are often transferred between bacteria by mobile genetic vectors called plasmids. It is commonly believed that removal of antibiotic pressure will reduce the numbers of antibiotic-resistant bacteria due to the perception that carriage of resistance imposes a fitness cost on the bacterium. This study investigated the ability of the plasmid pCT, a globally distributed plasmid that carries an extended-spectrum-β-lactamase (ESBL) resistance gene (blaCTX-M-14), to persist and disseminate in the absence of antibiotic pressure. We investigated key attributes in plasmid success, including conjugation frequencies, bacterial-host growth rates, ability to cause infection, and impact on the fitness of host strains. We also determined the contribution of theblaCTX-M-14gene itself to the biology of the plasmid and host bacterium. Carriage of pCT was found to impose no detectable fitness cost on various bacterial hosts. An absence of antibiotic pressure and inactivation of the antibiotic resistance gene also had no effect on plasmid persistence, conjugation frequency, or bacterial-host biology. In conclusion, plasmids such as pCT have evolved to impose little impact on host strains. Therefore, the persistence of antibiotic resistance genes and their vectors is to be expected in the absence of antibiotic selective pressure regardless of antibiotic stewardship. Other means to reduce plasmid stability are needed to prevent the persistence of these vectors and the antibiotic resistance genes they carry.

Characterization of Antibiotic Resistance E. Coli and Antibiotic Resistance Genes in Aquatic Environment of Taihu Lake, China

2013 ◽  
Vol 295-298 ◽  
pp. 630-634 ◽  
Author(s):  
Ni Ni Han ◽  
Song He Zhang ◽  
Pei Fang Wang ◽  
Chao Wang
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Surface Water ◽  
Resistance Genes ◽  
Taihu Lake ◽  
Antibiotic Resistance Genes ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Realtime Pcr

The aims of this study are to evaluate multiple antibiotic resistant Escherichia coli isolated from surface water and to investigate the presence and distribution antibiotic resistance genes (ARGs) in sediments of Taihu Lake. The results show that the presentence of four ARGs concentrations in the sediments of the lake was in sequence: strB>qnrB>strA>qnrS, as determined by realtime-PCR technique. The southwest and east areas of Taihu Lake were polluted seriously than other areas from all kinds of antibiotics. The screening Escherichia coli had a higher resistance to streptomycin, tetracycline and ampicillin than other four antibiotics, and had a lowest resistance to levofloxacin.

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