Studies on the enzymatic synthesis of enterochelin in Escherichia coli K-12, Salmonella typhimurium and Klebsiella pneumoniae

1980 ◽  
Vol 614 (1) ◽  
pp. 185-195 ◽  
Author(s):  
Kenneth T. Greenwood ◽  
Richard K.J. Luke
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Salmonella Typhimurium ◽  
Enzymatic Synthesis ◽  
K 12

scholarly journals A study of the genotoxic potential of flavonoids using short-term bacterial assays.

1993 ◽  
Vol 40 (4) ◽  
pp. 549-554 ◽  
Author(s):  
H Czeczot ◽  
J Kusztelak
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Mutagenic Effect ◽  
Short Term ◽  
Sos System ◽  
Genotoxic Potential ◽  
Sos Chromotest ◽  
Activation System ◽  
K 12 ◽  
Alkylate Dna

Genotoxic activities of flavonoids (quercetin, rhamnetin, isorhamnetin, apigenin, luteolin) were investigated using two short-term bacterial assays. In the "repair test" in Salmonella typhimurium (strains TA1538 uvrB- and TA1978 uvrB+) the flavonoids studied did not introduce any damage into the DNA recognized by UvrABC nuclease (correndonuclease II). The results of the SOS-Chromotest in Escherichia coli K-12 strains PQ37 (tag+, alk+) and PQ243 (tagA, alkA) indicated that flavonoids only weakly induced the SOS system. The addition of a liver activation system (S9 mix) did not increase the mutagenic effect of the flavonoids tested. Two compounds: rhamnetin, isorhamnetin and their putative metabolites formed in the presence of the S9 mix did not alkylate DNA at N-3 of adenine.

Nucleotide sequence of the metH gene of Escherichia coli K-12 and comparison with that of Salmonella typhimurium LT2

Gene ◽  
1990 ◽  
Vol 87 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Iain G. Old ◽  
Danielle Margarita ◽  
Robert E. Glass ◽  
Isabelle Saint Girons
Keyword(s):  
Escherichia Coli ◽  
Nucleotide Sequence ◽  
Salmonella Typhimurium ◽  
K 12

scholarly journals Plasmid studies ofSalmonella typhimuriumphage type 179 resistant to ampicillin, tetracycline, sulphonamides and trimethoprim

1980 ◽  
Vol 85 (2) ◽  
pp. 293-300 ◽  
Author(s):  
D. M. Anderson
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
New Zealand ◽  
Salmonella Typhimurium ◽  
National Health ◽  
Gel Electrophoresis ◽  
Phage Type ◽  
Agarose Gel ◽  
Agarose Gel Electrophoresis ◽  
K 12

SUMMARYSixteen strains ofSalmonella typhimuriumphage type 179 were referred to the National Health Institute, Wellington, New Zealand, from 1977 to 1979. This phage type had not been observed here before 1977. All strains were resistant to ampicillin, several were also resistant to tetracycline, and several were resistant to ampicillin, tetracycline, sulphafurazele and trimethoprim. All resistances could be transferred toEscherichia coliK 12. Plasmids from these strains and their transconjugants were characterized by agarose gel electrophoresis. It appears that resistance to sulphafurazole and trimethoprim is carried on a plasmid with a molecular weight of 5·2 Mdal and that resistance to ampicillin and tetracycline is carried on a plasmid with a molecular weight of approximately 60 Mdal.

scholarly journals Frecuencia de bacterias gramnegativas en teléfonos celulares de estudiantes de enfermería

SANUS ◽  
2019 ◽  
pp. 6-18
Author(s):  
María Isabel Álvarez-Rangel ◽  
Gerardo Flores-Patiño ◽  
Itzen Lazarini-Torres ◽  
Said Alejandro Cazares-Patiño ◽  
Dolores Monserrat Silva-Camacho ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Salmonella Typhimurium ◽  
Enterobacter Aerogenes ◽  
Salmonella Typhi ◽  
Para Determinar

Introducción: Hoy en día, el uso indiscriminado del teléfono celular ha llevado a manipularlo en condiciones inadecuadas de higiene. Objetivo: Identificar la frecuencia de bacterias gramnegativas (Salmonella typhimurium, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae y Pseudomona aeruginosa) en los teléfonos celulares de los estudiantes de la Licenciatura en Enfermería de una Universidad del centro de México. Metodología: El estudio corresponde a un enfoque cuantitativo, transversal y un alcance descriptivo. Se realizó un muestreo no probabilístico por conveniencia, eligiendo a 60 alumnos con previo consentimiento informado. Se tomaron las muestras en los teléfonos celulares, se procedió a la incubación por 24 horas en tubos con medio Soya Tripticaseína, se sembró en cajas petri, dejándose incubar por 48 horas y se procedió a la caracterización morfológica de las bacterias para determinar su presencia. Resultados: Del 100% de las muestras, el 41.67% no presentó crecimiento bacteriano y en el 58.33% de los teléfonos se obtuvieron los siguientes resultados: Salmonella Typhi con 2.98%, Enterobacter Aerogenes 28.35%, Escherichia Coli 28.35%, Klebsiella 11.94%, Pseudomona 0.00% y otras 28.35%. Conclusión: La mayoría de la muestra de estudio, porta en sus teléfonos celulares bacterias potencialmente patógenas, lo que supone un riesgo de contaminación cruzada y una posible fuente de brotes de infecciones intra y extrahospitalarias.

Cefotaximases (CTX-M-ases), an expanding family of extended-spectrum β-lactamases

2004 ◽  
Vol 50 (3) ◽  
pp. 137-165 ◽  
Author(s):  
Jan Walther-Rasmussen ◽  
Niels Høiby
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Salmonella Typhimurium ◽  
Vibrio Cholerae ◽  
Proteus Mirabilis ◽  
Aeromonas Hydrophila ◽  
Insertion Sequences ◽  
Class A ◽  
Extended Spectrum ◽  
Genes Encoding

Among the extended-spectrum β-lactamases, the cefotaximases (CTX-M-ases) constitute a rapidly growing cluster of enzymes that have disseminated geographically. The CTX-M-ases, which hydrolyze cefotaxime efficiently, are mostly encoded by transferable plasmids, and the enzymes have been found predominantly in Enterobacteriaceae, most prevalently in Escherichia coli, Salmonella typhimurium, Klebsiella pneumoniae, and Proteus mirabilis. Isolates of Vibrio cholerae, Acinetobacter baumannii, and Aeromonas hydrophila encoding CTX-M-ases have also been reported. The CTX-M-ases belong to the molecular class A β-lactamases, and the enzymes are functionally characterized as extended-spectrum β-lactamases. This group of β-lactamases confers resistance to penicillins, extended-spectrum cephalosporins, and monobactams, and the enzymes are inhibited by clavulanate, sulbactam, and tazobactam. Typically, the CTX-M-ases hydrolyze cefotaxime more efficiently than ceftazidime, which is reflected in substantially higher MICs to cefotaxime than to ceftazidime. Phylogenetically, the CTX-M-ases are divided into four subfamilies that seem to have descended from chromosomal β-lactamases of Kluyvera spp. Insertion sequences, especially ISEcp1, have been found adjacent to genes encoding enzymes of all four subfamilies. The class I integron-associated orf513 also seems to be involved in the mobilization of blaCTX-M genes. This review discusses the phylogeny and the hydrolytic properties of the CTX-M-ases, as well as their geographic occurrence and mode of spread.Key words: extended-spectrum β-lactamases, cefotaximases, phylogeny, dissemination, hydrolytic properties.

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