scholarly journals Mutations Which Uncouple Transport and Phosphorylation in the d-Mannitol Phosphotransferase System of Escherichia coli K-12 and Klebsiella pneumoniae 1033-5P14

2003 ◽  
Vol 185 (7) ◽  
pp. 2267-2276 ◽  
Author(s):  
Susanne Otte ◽  
Annette Scholle ◽  
Sevket Turgut ◽  
Joseph W. Lengeler
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Klebsiella Oxytoca ◽  
Single Copy ◽  
High Rate ◽  
Phosphotransferase System ◽  
Good Efficiency ◽  
In The Wild ◽  
Different Strains ◽  
K 12

ABSTRACT Mutants of Escherichia coli K-12 were isolated which lack the normal phosphotransferase system-dependent catabolic pathway for d-mannitol (Mtl). In some mutants the pts genes for the general proteins enzyme I and histidine protein of the phosphoenolpyruvate-dependent carbohydrate phosphotransferase systems were deleted. Other mutants expressed truncated mannitol-specific enzymes II (IIMtl) which lacked the IIAMtl or IIBAMtl domain(s), and the mtlA genes originated either from E. coli K-12 or from Klebsiella pneumoniae 1033-5P14. The dalD gene from Klebsiella oxytoca M5a1 was cloned on single-copy plasmids and transformed into the strains described above. This gene encodes an NAD-dependent d-arabinitol dehydrogenase (DalD) which converts d-arabinitol into d-xylulose and also converts d-mannitol into d-fructose. The different strains were used to isolate mutations which allow efficient transport of mannitol through the nonphosphorylated IIMtl complexes by selecting for growth on this polyhydric alcohol. More than 40 different mutants were analyzed to determine their ability to grow on mannitol, as well as their ability to bind and transport free mannitol and, after restoration of the missing domain(s), their ability to phosphorylate mannitol. Four mutations were identified (E218A, E218V, H256P, and H256Y); all of these mutations are located in the highly conserved loop 5 of the IIC membrane-bound transporter, and two are located in its GIHE motif. These mutations were found to affect the various functions in different ways. Interestingly, in the presence of all IIMtl variants, whether they were in the truncated form or in the complete form, in the phosphorylated form or in the nonphosphorylated form, and in the wild-type form or in the mutated form, growth occurred on the low-affinity analogue d-arabinitol with good efficiency, while only the uncoupled mutated forms transported mannitol at a high rate.

Антимікробна резистентність провідних збудників інфекцій сечових шляхів у Києві (Україна)

2017 ◽  
Vol 1 (2) ◽  
pp. 48-60
Author(s):  
A.G. Salmanov ◽  
A.V. Rudenko
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Staphylococcus Epidermidis ◽  
Klebsiella Oxytoca ◽  
Enterobacter Aerogenes ◽  
Enterobacter Cloacae ◽  
Proteus Vulgaris ◽  
Providencia Rettgeri ◽  
E Coli

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.

scholarly journals Glucose Transporter Mutants of Escherichia coli K-12 with Changes in Substrate Recognition of IICBGlc and Induction Behavior of theptsG Gene

2000 ◽  
Vol 182 (16) ◽  
pp. 4443-4452 ◽  
Author(s):  
Tim Zeppenfeld ◽  
Christina Larisch ◽  
Joseph W. Lengeler ◽  
Knut Jahreis
Keyword(s):  
Escherichia Coli ◽  
Glucose Transporter ◽  
Regulatory Mechanism ◽  
Single Copy ◽  
Amino Acid Residues ◽  
Inducer Exclusion ◽  
Membrane Bound ◽  
Dominance Tests ◽  
K 12 ◽  
Enzyme I

ABSTRACT In Escherichia coli K-12, the major glucose transporter with a central role in carbon catabolite repression and in inducer exclusion is the phosphoenolpyruvate-dependent glucose:phosphotransferase system (PTS). Its membrane-bound subunit, IICBGlc, is encoded by the gene ptsG; its soluble domain, IIAGlc, is encoded by crr, which is a member of the pts operon. The system is inducible by d-glucose and, to a lesser degree, byl-sorbose. The regulation of ptsG transcription was analyzed by testing the induction of IICBGlctransporter activity and of a single-copy Φ(ptsGop-lacZ) fusion. Among mutations found to affect directly ptsGexpression were those altering the activity of adenylate cyclase (cyaA), the repressor DgsA (dgsA; also called Mlc), the general PTS proteins enzyme I (ptsI) and histidine carrier protein HPr (ptsH), and the IIAGlc and IIBGlc domains, as well as several authentic and newly isolated UmgC mutations. The latter, originally thought to map in the repressor gene umgC outside theptsG locus, were found to represent ptsGalleles. These affected invariably the substrate specificity of the IICBGlc domain, thus allowing efficient transport and phosphorylation of substrates normally transported very poorly or not at all by this PTS. Simultaneously, all of these substrates became inducers for ptsG. From the analysis of the mutants, fromcis-trans dominance tests, and from the identification of the amino acid residues mutated in the UmgC mutants, a new regulatory mechanism involved in ptsG induction is postulated. According to this model, the phosphorylation state of IIBGlc modulates IICGlc which, directly or indirectly, controls the repressor DgsA and hence ptsGexpression. By the same mechanism, glucose uptake and phosphorylation also control the expression of the pts operon and probably of all operons controlled by the repressor DgsA.

scholarly journals Cloacal enterobacteria isolated from captive roadside hawks (Rupornis magnirostris, GMELIN, 1788) and their antimicrobial susceptibility profile

2016 ◽  
Vol 53 (2) ◽  
pp. 207 ◽  
Author(s):  
Ewerton Fylipe De Araújo Silva ◽  
Joanna Francyne Silva de Barros ◽  
Kleber Botelho Fraga ◽  
Carolina Peixoto Magalhães ◽  
José Eduardo Garcia ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Antimicrobial Susceptibility ◽  
Klebsiella Oxytoca ◽  
Macconkey Agar ◽  
Salmonella Spp ◽  
Antimicrobial Susceptibility Profile

O conhecimento das enterobactérias presentes em Gavião-carijó pode trazer uma compreensão sobre as doenças infecciosas que podem acometer essa ave, como também outros animais e/ou humanos, além de trazer mais informações sobre essa espécie de grande importância ecológica. Desta forma, o objetivo do estudo foi determinar as enterobactérias presentes na cloaca de Gaviões-carijós cativos e seu perfil de susceptibilidade a antimicrobianos. Inicialmente, foram coletadas amostras cloacais de nove espécimes com o auxílio de swabs. As amostras foram plaqueadas em ágar MacConkey, ágar Hektoen, ágar EMB e ágar SS e incubadas por 24 h a 35°C. Após incubação, as colônias foram submetidas às provas bioquímicas para confirmação da presença de enterobactérias. Posteriormente, o perfil de susceptibilidade das bactérias frente a agentes antimicrobianos foi avaliado através do teste da difusão em disco de acordo com o Clinical and Laboratory Standards Institute (CLSI). Escherichia coli (77,8%), Klebsiella oxytoca (11,1%), Klebsiella pneumoniae (11,1%) e Salmonella spp. (55,6%) foram isoladas das amostras coletadas. Dentre as cepas isoladas, algumas apresentaram resistência a até três antimicrobianos. O presente estudo trouxe um maior conhecimento sobre as enterobactérias presentes no Gavião-carijó (Rupornis magnirostris), mostrando um percentual significativo de enterobactérias de importância na saúde pública, evidenciando também a ocorrência de cepas com perfil de resistência a agentes antimicrobianos.

scholarly journals Prevalência das famílias TEM, SHV e CTX-M de β-lactamases de espectro estendido em Escherichia coli e Klebsiella spp no Hospital Universitário de Santa Maria, Estado do Rio Grande do Sul

2009 ◽  
Vol 42 (5) ◽  
pp. 556-560 ◽  
Author(s):  
Caio Fernando de Oliveira ◽  
Nara Lucia Frazzon Dal Forno ◽  
Izabel Almeida Alves ◽  
Jorge André Horta ◽  
Alexandre Rieger ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Klebsiella Oxytoca ◽  
Rio Grande ◽  
Rio Grande Do Sul ◽  
Santa Maria ◽  
Klebsiella Spp

Neste estudo estimou-se a distribuição e prevalência de β-lactamases de espectro estendido pertencentes às famílias TEM, SHV e CTX-M entre amostras de Escherichia coli e Klebsiella spp. no Hospital Universitário de Santa Maria, Rio Grande do Sul. Durante 14 meses, 90 microrganismos foram selecionados como prováveis produtores de ESBL. Os isolados foram submetidos a testes fenotípicos confirmatórios para a presença de ESBL. A seguir, os tipos de ESBLs presentes em cada microrganismo foram determinados através da pesquisa dos respectivos genes através da reação em cadeia da polimerase. Empregando-se o método do disco combinado, a presença de ESBLs foi confirmada em 55 (61,1%) amostras; quando o método do duplo disco foi utilizado, 57 (63,3%) amostras foramprodutoras de ESBLs. Com base na PCR, as ESBLs do tipo TEM e SHV foram mais presentes em Klebsiella pneumoniae enquanto que ESBL do tipo CTX-M foram mais presentes em Klebsiella oxytoca.

scholarly journals Convergent Pathways for Utilization of the Amino Sugars N-Acetylglucosamine,N-Acetylmannosamine, and N-Acetylneuraminic Acid by Escherichia coli

1999 ◽  
Vol 181 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Jacqueline Plumbridge ◽  
Eric Vimr
Keyword(s):  
Escherichia Coli ◽  
Carbon Sources ◽  
Amino Sugars ◽  
Good Growth ◽  
Gene Products ◽  
Phosphotransferase System ◽  
Regulatory Mutation ◽  
Putative Gene ◽  
Acetylneuraminic Acid ◽  
K 12

ABSTRACT N-Acetylglucosamine (GlcNAc) andN-acetylneuraminic acid (NANA) are good carbon sources forEscherichia coli K-12, whereasN-acetylmannosamine (ManNAc) is metabolized very slowly. The isolation of regulatory mutations which enhanced utilization of ManNAc allowed us to elucidate the pathway of its degradation. ManNAc is transported by the manXYZ-encoded phosphoenolpyruvate-dependent phosphotransferase system (PTS) transporter producing intracellular ManNAc-6-P. This phosphorylated hexosamine is subsequently converted to GlcNAc-6-P, which is further metabolized by the nagBA-encoded deacetylase and deaminase of the GlcNAc-6-P degradation pathway. Two independent mutations are necessary for good growth on ManNAc. One mutation maps tomlc, and mutations in this gene are known to enhance the expression of manXYZ. The second regulatory mutation was mapped to the nanAT operon, which encodes the NANA transporter and NANA lyase. The combined action of thenanAT gene products converts extracellular NANA to intracellular ManNAc. The second regulatory mutation defines an open reading frame (ORF), called yhcK, as the gene for the repressor of the nan operon (nanR). Mutations in the repressor enhance expression of the nanAT genes and, presumably, three distal, previously unidentified genes,yhcJIH. Expression of just one of these downstream ORFs,yhcJ, is necessary for growth on ManNAc in the presence of an mlc mutation. The yhcJ gene appears to encode a ManNAc-6-P-to-GlcNAc-6-P epimerase (nanE). Another putative gene in the nan operon, yhcI, likely encodes ManNAc kinase (nanK), which should phosphorylate the ManNAc liberated from NANA by the NanA protein. Use of NANA as carbon source by E. coli also requires thenagBA gene products. The existence of a ManNAc kinase and epimerase within the nan operon allows us to propose that the pathways for dissimilation of the three amino sugars GlcNAc, ManNAc, and NANA, all converge at the step of GlcNAc-6-P.

Effect of ozone on prophage induction in different strains of Escherichia coli K-12 lysogenic for lambda

1984 ◽  
Vol 26 (6) ◽  
pp. 706-709 ◽  
Author(s):  
Pierre L'Hérault ◽  
Young Sup Chung
Keyword(s):  
Escherichia Coli ◽  
Ultraviolet Light ◽  
Lytic Cycle ◽  
Prophage Induction ◽  
E Coli ◽  
Different Strains ◽  
K 12 ◽  
Lambda Prophage

Ozone was tested for its effect upon induction of lambda prophage in two different strains of Escherichia coli K-12. Based on the induction index and when compared to ultraviolet light, ozone appeared to be a weak, if any at all, inducer of the lytic cycle in E. coli. This is in agreement with other studies which have suggested that this agent is a weak inducer of the SOS functions.Key words: SOS functions, ultraviolet light, mutagen, ozone.

scholarly journals Multiple-Antibiotic Resistance Mediated by Plasmids and Integrons in Uropathogenic Escherichia coli and Klebsiella pneumoniae

1970 ◽  
Vol 24 (1) ◽  
pp. 19-23 ◽  
Author(s):  
Taslima Taher Lina ◽  
Sabita Rezwana Rahman ◽  
Donald James Gomes
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Urinary Tract Infection ◽  
Antibiotic Resistance ◽  
Urinary Tract ◽  
Tract Infection ◽  
Klebsiella Pneumoniae ◽  
High Rate ◽  
E Coli ◽  
Class 1

Antibiotic resistance in urinary tract infection (UTI) is a growing public health problem in the world. In this study, a total of 182 uropathogens were isolated from patients with symptoms of urinary tract infection (UTI). Escherichia coli (88%) was the most prevalent isolate, while Klebsiella pneumoniae was recovered from 12% cases. The male/female ratio was 1:3. About 56% female and 51% male patients belonged to the age group >40 years. The antibiotic resistance rates of the isolates to fifteen different drugs were investigated. E. coli and K. pneumoniae showed variable pattern of susceptibility. The percentage of resistance to different drugs was higher in E. coli isolates compared to that of K. pneumoniae. Among the total number of isolates about 87% were resistant to at least three commonly used antibiotics. All the isolates were sensitive to imipenem. Analysis of the plasmid DNA had shown that the plasmid pattern was very diverse in both E. coli and K. pneumoniae. All the isolates contained multiple numbers of plasmid ranging from 1.0 to >140 MDa. Middleranged plasmids (30 to 80 MDa), the transferable resistance plasmids, were found to be present in 86% E. coli and 85% K. pneumoniae isolates. The strong association observed between plasmid profiles and drug resistance patterns suggest that plasmids other than the common plasmids may have epidemiological significance. The presence of class 1 and class 2 integrons were also investigated. A relatively high occurrence of class 1 integrons, that are associated with lateral transfer of antibacterial resistance genes, was observed in K. pneumoniae (88%) than in E. coli isolates (54%). Class 2 integrons were not found in any of the E. coli and K. pneumoniae isolates. These results show the high rate of drug resistance and the presence of high rate of transferable elements in these MDR isolates. Keywords: Uropathogens, Escherichia coli, Klebsiella pneumoniae, Multidrug-resistant (MDR) bacteria, Plasmid profiles, IntegronsDOI: http://dx.doi.org/10.3329/bjm.v24i1.1231 Bangladesh J Microbiol, Volume 24, Number 1, June 2007, pp 19-23

COMPLEX POLYSACCHARIDES IN DIFFERENT STRAINS OF ESCHERICHIA COLI K-12

1966 ◽  
Vol 133 (2 Molecular Bio) ◽  
pp. 425-437 ◽  
Author(s):  
Annette M. C. Rapin ◽  
Hubert Mayer
Keyword(s):  
Escherichia Coli ◽  
Different Strains ◽  
K 12
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