Colonization resistance against potentially pathogenic bacteria in hexaflora-associated gnotobiotic mice

1978 ◽  
Vol 24 (2) ◽  
pp. 79-83 ◽  
Author(s):  
Kunwar K. Srivastava

A study of colonization resistance against potentially pathogenic bacteria (Escherichia coli and Pseudomonas aeruginosa) was conducted in hexaflora-associated gnotobiotic mice. Groups of germfree AKR mice were swabbed with five bacterial and a single gastrointestinal yeast species: Streptococcus faecalis, Lactobacillus brevis, Staphylococcus epidermidis, Enterobacter aerogenes, Bacteroides fragilis var. vulgatus, and Torulopsis sp. All species became established in the gut in 8 weeks. Later these associated mice were divided and challenged by four graded doses of E. coli or P. aeruginosa. The presence of challenge organism was monitored specifically in the freshly voided fecal specimens of the challenged mice. Escherichia coli colonized the gut of each mouse at each level up to 60 days post challenge. Pseudomonas aeruginosa was completely eliminated from each mouse at each dose level after 30 days post challenge. Evidence suggests that all six species were sufficient to prevent the colonization of P. aeruginosa and not of E. coli in the gut of the gnotobiotic mice.

2017 ◽  
Vol 1 (2) ◽  
pp. 48-60
Author(s):  
A.G. Salmanov ◽  
A.V. Rudenko

Мета роботи — вивчити резистентність до антибіотиків бактеріальних збудників інфекцій сечових шляхів (ІСШ), виділених у пацієнтів урологічного стаціонару в м. Києві. Матеріали і методи. Досліджено 1612 штамів бактерій, виділених із сечі хворих з ІСШ (цистит, уретрит, пієлонефрит), госпіталізованих в урологічне відділення ДУ «Інститут урології НАМН України» у м. Києві протягом 2016 р. Серед пацієнтів переважали жінки — 1201 (74,5 %). Вік хворих становив від 17 до 74 років. Для збору даних використано медичну документацію лікарні. Мікробіологічні дослідження виконано у лабораторії мікробіології ДУ «Інститут урології НАМН України». Аналізували результати культурального дослідження зразків сечі, зібраних за наявності клінічних ознак ІСШ. Дослідження клінічного матеріалу та інтерпретацію отриманих результатів проводили загальноприйнятими методами. Вивчено чутливість уропатогенів до 31 антибіотика дискодифузійним методом відповідно до рекомендацій Інституту клінічних та лабораторних стандартів США (Clinical and Laboratory Standards Institute (CLSI)). Результати та обговорення. Аналіз мікробного спектра сечі виявив домінування серед уропатогенів штамів Escherichia coli (32,0 %), Enterococcus faecalis (19,5 %), Klebsiella pneumoniae (10,9 %), Staphylococcus epidermidis (8,9 %), S. haemolyticus (6,5 %) та Pseudomonas aeruginosa (6,4 %). Частка Enterococcus faecium, Enterobacter aerogenes і Streptococcus viridans становила відповідно 2,5, 2,2 і 1,6 %, Enterobacter cloacae, Klebsiella oxytoca, Acinetobacter baumannii, Proteus vulgaris та Providencia rettgeri — менше 1,0 %. У більшості випадків (69,7 %) мікроорганізми виділено у монокультурі, у решті випадків — у мікробних асоціа- ціях. Високу резистентність до тестованих антибіотиків виявили штами E. aerogenes (45,1 %), E. cloacae (45,7 %), E. faecium (40,9 %), E. faecalis (40,7 %), E. coli (39,9 %), P. aeruginosa (34,0 %), K. pneumoniae (28,6 %). Найбільш активними до уропатогенів були іміпенем (E. coli — 87,6 %, P. aeruginosa — 75,7 %, E. cloacae — 67,3 %, E. aerogenes — 72,6 %, K. pneumoniae — 93,2 %), меропенем (E. coli — 89,1 %, P. aeruginosa — 76,7 %, K. pneumoniae — 82,6 %), лефлоцин (E. coli — 74,5 %, ентерококи — 78,7 %, P. aeruginosa — 76,7 %, E. cloacae — 73,9 %, E. aerogenes — 80,4 %, K. pneumoniae — 83,5 %), амоксицилін/клавуланат (ентерококи — 84,6 %), фурагін (ентерококи — 82,6 %), цефоперазон (K. pneumoniae — 89,2 %, P. aeruginosa — 73,8 %), цефтріаксон (K. pneumoniae — 80,1 %). Висновки. Антибіотикорезистентність збудників ІСШ — важлива терапевтична проблема. Найбільшою активністю до уропатогенів характеризуються іміпенем, меропенем, лефлоцин, амоксицилін/ клавуланат, фурагін, цефоперазон, цефтріаксон, які можна розглядати як препарат вибору для призначення стартової терапії ІСШ. Необхідно здійснювати постійний моніторинг за резистентністю до дії антибіотиків. Політику використання антибіотиків у кожному стаціонарі слід визначати залежно від локальних даних щодо резистентності до протимікробних препаратів.


2020 ◽  
Vol 367 (22) ◽  
Author(s):  
Chris Coward ◽  
Gopujara Dharmalingham ◽  
Omar Abdulle ◽  
Tim Avis ◽  
Stephan Beisken ◽  
...  

ABSTRACT The use of bacterial transposon mutant libraries in phenotypic screens is a well-established technique for determining which genes are essential or advantageous for growth in conditions of interest. Standard, inactivating, transposon libraries cannot give direct information about genes whose over-expression gives a selective advantage. We report the development of a system wherein outward-oriented promoters are included in mini-transposons, generation of transposon mutant libraries in Escherichia coli and Pseudomonas aeruginosa and their use to probe genes important for growth under selection with the antimicrobial fosfomycin, and a recently-developed leucyl-tRNA synthase inhibitor. In addition to the identification of known mechanisms of action and resistance, we identify the carbon–phosphorous lyase complex as a potential resistance liability for fosfomycin in E. coli and P. aeruginosa. The use of this technology can facilitate the development of novel mechanism-of-action antimicrobials that are urgently required to combat the increasing threat worldwide from antimicrobial-resistant pathogenic bacteria.


2021 ◽  
Vol 10 (3) ◽  
pp. e43910313516
Author(s):  
Lucas Harassim ◽  
Olibio Lopes Fiebig da Silva ◽  
Luiz Felipe Soares Pinheiro ◽  
Elber José Assaiante dos Santos ◽  
Cláudio Daniel Cerdeira ◽  
...  

A Infecção no Trato Urinário (ITU) acometendo pacientes em Unidades de Terapia Intensiva (UTIs) é uma realidade preocupante, agravada pelo uso irracional de antimicrobianos e a alarmante multirresistência em microrganismos. Nós avaliamos o nível de assertividade quanto ao uso de antimicrobianos durante à antibioticoterapia empírica (ATE), em pacientes diagnosticados com ITU, comparando tal tratamento farmacológico empírico e o realizado após o antibiograma (antibioticoterapia direcionada), além disto, estimamos a prevalência dos agentes etiológicos e analisamos os fatores de risco associados. Este é um estudo observacional e transversal, realizado em 2015, no qual foram avaliados pacientes de ambos os sexos e todas as idades apresentando ITU e submetidos à antibioticoterapia, internados em uma UTI de um hospital no sul de Minas Gerais, Brasil. Dos 49 pacientes avaliados (28 mulheres [M] e 21 homens [H]), a média de idade foi 55±19 anos (IC(95) 49-61) e a faixa etária ≥70 anos foi a predominante. Quatorze diferentes microrganismos foram causadores de ITUs, sendo que 28,3% (IC(95%) 16,2-40,4) dos isolados clínicos tiveram Escherichia coli como o agente etiológico (33,3% H e 28,6% M); 18,9% (IC(95%) 8,3-29,4) Acinetobacter baumannii (33,3% H e 10,7% M); 15,1% (IC(95%) 5,5-24,7) Klebsiella pneumoniae (19% H e 14,3% M); 11,3% Pseudomonas aeruginosa (9,5% H e 14,3% M); 5,7% Enterobacter aerogenes (14,3% H); 3,8% Klebsiella oxytoca; 3,8% Staphylococcus aureus (7,1% M); e 1,9% para cada um dos seguintes microrganismos: Enterococcus faecalis (4,8% H); Proteus mirabilis (3,6% M); Enterobacter cloacae (3,6% M); Providencia rettgeri (4,8% H); Citrobacter koseri (3,6% M); Citrobacter freundii (3,6% M); e Fungos leveduriformes (4,8% H). As prevalências de ITUs causadas por A. baumannii e P. aeruginosa foram influenciadas pelo sexo (χ² com p<0,001). No sexo masculino, houve correlações positivas “substanciais” entre o aumento da idade (em anos) e a prevalência de ITU causada por E. coli (r = 0,69) ou entre idades menos avançadas e a prevalência de ITU causada por A. baumannii (r = -0,7). No sexo feminino, houve uma correlação positiva “extremamente forte” entre o aumento da idade e a prevalência de ITU causada por E. coli (r = 0,94; IC(95) 0,66-0,99; p<0,0014). Os antibióticos mais utilizados de forma empírica (ATE) foram: Ciprofloxacina (14,3% IC(95%) 4,7-24,1), Cefepima (14,3%) e Vancomicina (10%), e após o antibiograma (antibioticoterapia direcionada): Ceftazidima (16,3% IC(95%) 6-26,7), Ciprofloxacina (14,3% IC(95%) 4,5-24,1), Polimixina B (10,2%), Imipenem (10,2%) e Ampicilina + Sulbac. (8,2%). Em 20% dos casos, as terapias empíricas (ATE) foram consideradas “inapropriadas/não acertadas”. Contudo, também devemos ter ciência da necessidade clínica e quanto ao imediatismo para o tratamento de uma ITU em UTI, uma vez que a doença pode ser fatal se uma terapia não for instituída, portanto, nós aconselhamos avaliações mais minuciosas, tanto da racionalidade do uso de antibióticos, quanto dos fatores de risco para o desenvolvimento de ITUs em UTIs.


2016 ◽  
Author(s):  
Kristina Doxsee ◽  
Ryan Berthelot ◽  
Suresh Neethirajan

Electrotaxis or galvanotaxis refers to the migration pattern of cells induced in response to electrical potential. Although it has been extensively studied in mammalian cells, electrotaxis has not been explored in detail in bacterial cells; information regarding the impact of current on pathogenic bacteria is severely lacking. Therefore, we designed a series of single and multi-cue experiments to assess the impact of varying currents on bacterial motility dynamics in pathogenic multi-drug resistant (MDR) strains of Pseudomonas aeruginosa and Escherichia coli using a microfluidic platform. Motility plays key roles in bacterial migration and the colonization of surfaces during the formation of biofilms, which are inherently recalcitrant to removal and resistant to traditional disinfection strategies (e.g. antibiotics). Use of the microfluidic platform allows for exposure to current, which can be supplied at a range that is biocidal to bacteria, yet physiologically safe in humans (single cue). This system also allows for multi-cue experiments where acetic acid, a relatively safe compound with anti-fouling/antimicrobial properties, can be combined with current to enhance disinfection. These strategies may offer substantial therapeutic benefits, specifically for the treatment of biofilm infections, such as those found in the wound environment. Furthermore, microfluidic systems have been successfully used to model the unique microfluidic dynamics present in the wound environment, suggesting that these investigations could be extended to more complex biological systems. Our results showed that the application of current in combination with acetic acid has profound inhibitory effects on MDR strains of P. aeruginosa and E. coli, even with brief applications. Specifically, E. coli motility dynamics and cell survival were significantly impaired starting at a concentration of 125 μA DC and 0.31% acetic acid, while P. aeruginosa was impaired at 70 μA and 0.31% acetic acid. As these strains are relevant wound pathogens, it is likely that this strategy would be effective against similar strains in vivo and could represent a new approach to hasten wound healing.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
George M. Ongwae ◽  
Mahendra D. Chordia ◽  
Jennie L. Cawley ◽  
Brianna E. Dalesandro ◽  
Nathan J. Wittenberg ◽  
...  

AbstractBacteriophages are highly abundant molecular machines that have evolved proteins to target the surface of host bacterial cells. Given the ubiquity of lipopolysaccharides (LPS) on the outer membrane of Gram-negative bacteria, we reasoned that targeting proteins from bacteriophages could be leveraged to target the surface of Gram-negative pathogens for biotechnological applications. To this end, a short tail fiber (GP12) from the T4 bacteriophage, which infects Escherichia coli (E. coli), was isolated and tested for the ability to adhere to whole bacterial cells. We found that, surprisingly, GP12 effectively bound the surface of Pseudomonas aeruginosa cells despite the established preferred host of T4 for E. coli. In efforts to elucidate why this binding pattern was observed, it was determined that the absence of the O-antigen region of LPS on E. coli improved cell surface tagging. This indicated that O-antigens play a significant role in controlling cell adhesion by T4. Probing GP12 and LPS interactions further using deletions of the enzymes involved in the biosynthetic pathway of LPS revealed the inner core oligosaccharide as a possible main target of GP12. Finally, we demonstrated the potential utility of GP12 for biomedical applications by showing that GP12-modified agarose beads resulted in the depletion of pathogenic bacteria from solution.


2000 ◽  
Vol 44 (1) ◽  
pp. 213-216 ◽  
Author(s):  
Helene Marchandin ◽  
Helene Jean-Pierre ◽  
Christophe De Champs ◽  
Danielle Sirot ◽  
Helene Darbas ◽  
...  

ABSTRACT Several Pseudomonas aeruginosa strains, including one urinary isolate producing an extended-spectrum β-lactamase TEM-24, were isolated from a long-term-hospitalized woman. Three TEM-24-producing enterobacterial species (Enterobacter aerogenes, Escherichia coli, and Proteus mirabilis) were isolated from the same patient. TEM-24 and the resistance markers for aminoglycosides, chloramphenicol, and sulfonamide were encoded by a 180-kb plasmid transferred by conjugation into E. coli HB101.


1995 ◽  
Vol 31 (5-6) ◽  
pp. 75-79 ◽  
Author(s):  
M. Würzer ◽  
A. Wiedenmann ◽  
K. Botzenhart

In Germany the application of procedures such as flocculation and filtration in the preparation of drinking water results in the annual production of an estimated 500,000 t of sediments and sludges. Some of these residues have a potential for being reused, for example in agriculture, forestry, brickworks or waste water treatment. To assess the microbiological quality of residues from waterworks methods for the detection of enterobacteria, Escherichia coli, Salmonella, Pseudomonas aeruginosa, Legionella, poliovirus, Ascaris suis eggs and Cryptosporidium have been evaluated regarding their detection limits and were applied to various residues from German waterworks. Results show that sediments and sludges may contain pathogenic bacteria, viruses and protista. When residues from waterworks are intended to be reused in agriculture or forestry the microbiological quality should therefore be considered.


Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1541
Author(s):  
Jie Zhang ◽  
Jia Wang ◽  
Qingjun Zhu ◽  
Binbin Zhang ◽  
Huihui Xu ◽  
...  

A novel AgBr/Ag2MoO4@InVO4 composite photocatalyst with different heterojunction structures was successfully constructed by compounding InVO4 with Ag2MoO4 and AgBr. According to the degradation, antibacterial and free radical trapping data, the photocatalytic antibacterial and antifouling activities of AgBr/Ag2MoO4@InVO4 composite were evaluated, and the corresponding photocatalytic reaction mechanism was proposed. Adding AgBr/Ag2MoO4@InVO4 composite, the degradation rate of ciprofloxacin (CIP) achieved 95.5% within 120 min. At the same time, the antibacterial rates of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) achieved 99.99%. The AgBr/Ag2MoO4@InVO4 composite photocatalyst showed promising usage in photocatalytic antibacterial and purification areas.


2015 ◽  
Vol 78 (9) ◽  
pp. 1738-1744 ◽  
Author(s):  
MICHAEL KNOWLES ◽  
DOMINIC LAMBERT ◽  
GEORGE HUSZCZYNSKI ◽  
MARTINE GAUTHIER ◽  
BURTON W. BLAIS

Control strains of bacterial pathogens such as Escherichia coli O157:H7 are commonly processed in parallel with test samples in food microbiology laboratories as a quality control measure to assure the satisfactory performance of materials used in the analytical procedure. Before positive findings can be reported for risk management purposes, analysts must have a means of verifying that pathogenic bacteria (e.g., E. coli O157:H7) recovered from test samples are not due to inadvertent contamination with the control strain routinely handled in the laboratory environment. Here, we report on the application of an in-house bioinformatic pipeline for the identification of unique genomic signature sequences in the development of specific oligonucleotide primers enabling the identification of a common positive control strain, E. coli O157:H7 (ATCC 35150), using a simple PCR procedure.


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