scholarly journals The distribution of plasmids among a representative collection of Scottish strains of salmonellae

1986 ◽  
Vol 97 (2) ◽  
pp. 199-204 ◽  
Author(s):  
D. J. Platt ◽  
D. J. Brown ◽  
D. S. Munro
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Antibiotic Resistant ◽  
R Plasmids ◽  
The Difference

SummaryThe distribution of plasmids was studied in a representative collection of salmonella strains which comprised 98Salmonella typhimuriumand 96 other serotypes. Plasmids were detected in 72% of strains (mean 1·3 plasmids/strain) and individual strains harboured between 0 and 7 plasmids. They were more common amongS. typhimuriumthan other serotypes (incidence 92 and 53%; mean 1·9 and 0·8 plasmids/strain respectively). Although a higher proportion ofS. typhimurium(33%) were antibiotic-resistant compared to other serotypes (14%) the evidence presented indicated that R-plasmids were not responsible for the difference observed in the number and distribution of plasmids in these strains. These results were discussed in comparison with similar studies ofEscherichia coliand other enteric genera.

scholarly journals Incidences of antibiotic resistant fecal Escherichia coli strains isolated from healthy human in tokyo area in 1978 and their conjugative R plasmids.

1980 ◽  
Vol 29 (1) ◽  
pp. 39-45
Author(s):  
TOSHIHIKO ARAI ◽  
SADAO KOMATSU ◽  
YOKO KOMATSU ◽  
YUTAKA TAKASHIMA ◽  
HARUO KONDON
Keyword(s):  
Escherichia Coli ◽  
Healthy Human ◽  
Antibiotic Resistant ◽  
R Plasmids

Aquarium pets as a source of antibiotic-resistant salmonellae

1979 ◽  
Vol 25 (4) ◽  
pp. 535-541 ◽  
Author(s):  
T. J. Trust ◽  
Karen H. Bartlett
Keyword(s):  
Salmonella Typhimurium ◽  
Nalidixic Acid ◽  
The Other ◽  
Drug Resistant ◽  
Antibiotic Resistant ◽  
Resistance Patterns ◽  
R Plasmids

Thirteen serotypes of Salmonella isolated from imported ornamental aquarium frogs, snails, and their waters were shown to be multi-drug-resistant. Among the resistances exhibited were resistance to gentamicin, sulfamethoxazole–trimethoprim, cephalothin, and nalidixic acid. Frog isolates displayed eight different patterns and snail isolates had two different resistance patterns. The most common serotype, Salmonella typhimurium, was resistant to 18 antibacterials while other salmonellae were resistant to 9 to 16 antibacterials. Resistances in S. typhimurium and S. bovis-morbificans were conjugative and a number of R plasmids participated in the resistance. The plasmid-mediated resistance in S. typhimurium was stable and the levels of resistance conferred were markedly higher than in the other salmonellae tested. Resistance of other serotypes was non-conjugative and resistance to the β-lactam antibiotics was unstable.

scholarly journals Plasmid-mediated multiple antibiotic resistance of Escherichia coli in crude and treated wastewater used in agriculture

2009 ◽  
Vol 7 (2) ◽  
pp. 251-258 ◽  
Author(s):  
S. Pignato ◽  
M. A. Coniglio ◽  
G. Faro ◽  
F. X. Weill ◽  
G. Giammanco
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Treated Wastewater ◽  
Resistant Bacteria ◽  
Multiple Antibiotic Resistance ◽  
Reclaimed Wastewater ◽  
Salmonella Spp ◽  
Antibiotic Resistant ◽  
E Coli ◽  
R Plasmids

A total of 273 Escherichia coli isolates from raw and treated municipal wastewaters were investigated to evaluate the frequency and persistence of antibiotic resistance and to detect the occurrence of conjugative R plasmids and integrons. The highest resistance rates were against ampicillin (22.71%), tetracycline (19.41%), sulfamethoxazole (16.84%) and streptomycin (14.28%). Multiple antibiotic resistance was present in 24.17% of the isolates. Several multiple antibiotic-resistant isolates proved to be able to transfer en bloc their resistance patterns by conjugative R plasmids with different molecular sizes and restriction profiles. Class 1 integrons of 1 or 1.5 kbp were found in 5 out of 24 representative multiresistant E. coli isolates. Although wastewater treatments proved to be effective in eliminating Salmonella spp. and in reaching WHO microbiological standards for safe use of wastewater in agriculture, they were ineffective in reducing significantly the frequency of plasmid-mediated multiple antibiotic resistance in surviving E. coli. Since multiple antibiotic-resistant bacteria carrying integrons and conjugative R plasmids can constitute a reservoir of antibiotic-resistance genes in wastewater reclaimed for irrigation, risks for public health should be considered. Bacterial strains carrying R plasmids and integrons could contaminate crops irrigated with reclaimed wastewater and transfer their resistances to the consumers' intestinal bacteria.

scholarly journals Graphene-Assisted Sensor for Rapid Detection of Antibiotic Resistance in Escherichia coli

2021 ◽  
Vol 9 ◽  
Author(s):  
Chunlei Li ◽  
Feng Sun
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Environmental Pollutant ◽  
Resistant Bacteria ◽  
Electrocatalytic Reduction ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Drug Resistant Bacteria ◽  
The Difference ◽  
Reduced Activity

In recent years, antibiotic-resistant bacteria caused by antibiotic abuse in the medical industry have become a new environmental pollutant that endangers public health. Therefore, it is necessary to establish a detection method for evaluating drug-resistant bacteria. In this work, we used Escherichia coli as a target model and proposed a method to evaluate its drug resistance for three antibiotics. Graphene dispersion was used to co-mix with E. coli cells for the purpose of increasing the current signal. This electrochemical-based sensor allows the evaluation of the activity of E. coli on the electrode surface. When antibiotics were present, the electrocatalytic reduction signal was diminished because of the reduced activity of E. coli. Based on the difference in the electrochemical reduction signal, we can evaluate the antibiotic resistance of different E. coli strains.

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 Prevalence and Characterization of Extended-Spectrum β-Lactamase-Producing Antibiotic-Resistant Escherichia coli and Klebsiella pneumoniae in Ready-to-Eat Street Foods

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 850
Author(s):  
Shobha Giri ◽  
Vaishnavi Kudva ◽  
Kalidas Shetty ◽  
Veena Shetty
Keyword(s):  
Escherichia Coli ◽  
Food Safety ◽  
Klebsiella Pneumoniae ◽  
Rural Areas ◽  
Significant Risk ◽  
Microbiological Quality ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Extended Spectrum

As the global urban populations increase with rapid migration from rural areas, ready-to-eat (RTE) street foods are posing food safety challenges where street foods are prepared with less structured food safety guidelines in small and roadside outlets. The increased presence of extended-spectrum-β-lactamase (ESBL) producing bacteria in street foods is a significant risk for human health because of its epidemiological significance. Escherichia coli and Klebsiella pneumoniae have become important and dangerous foodborne pathogens globally for their relevance to antibiotic resistance. The present study was undertaken to evaluate the potential burden of antibiotic-resistant E. coli and K. pneumoniae contaminating RTE street foods and to assess the microbiological quality of foods in a typical emerging and growing urban suburb of India where RTE street foods are rapidly establishing with public health implications. A total of 100 RTE food samples were collected of which, 22.88% were E. coli and 27.12% K. pneumoniae. The prevalence of ESBL-producing E. coli and K. pneumoniae was 25.42%, isolated mostly from chutneys, salads, paani puri, and chicken. Antimicrobial resistance was observed towards cefepime (72.9%), imipenem (55.9%), cefotaxime (52.5%), and meropenem (16.9%) with 86.44% of the isolates with MAR index above 0.22. Among β-lactamase encoding genes, blaTEM (40.68%) was the most prevalent followed by blaCTX (32.20%) and blaSHV (10.17%). blaNDM gene was detected in 20.34% of the isolates. This study indicated that contaminated RTE street foods present health risks to consumers and there is a high potential of transferring multi-drug-resistant bacteria from foods to humans and from person to person as pathogens or as commensal residents of the human gut leading to challenges for subsequent therapeutic treatments.

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