Effects of oxygen upon freeze-dried and freeze-thawed bacteria: viability and free radical studies

1973 ◽  
Vol 19 (2) ◽  
pp. 189-194 ◽  
Author(s):  
C. S. Cox ◽  
R. J. Heckly
Keyword(s):  
Escherichia Coli ◽  
Free Radicals ◽  
Free Radical ◽  
Serratia Marcescens ◽  
Oxygen Concentration ◽  
Simple Relationship ◽  
E Coli ◽  
Freeze Dried ◽  
Escherichia Coli B ◽  
Oxygen Concentrations

Viability of freeze-dried Serratia marcescens 8UK was studied at 24.5 °C as a function of oxygen concentration and time. Results depended upon the source of the inoculum. Oxygen proved to be toxic and the kinetics (with respect to oxygen concentration) were first order at low oxygen concentrations and zero order at high oxygen concentrations. This indicates that the site for the action of oxygen can become saturated with oxygen. No simple relationship between viability and time was observed. Free radical studies were also made and showed that the detected free radicals were not involved in causing oxygen-induced loss of viability.The survival of Escherichia coli B frozen quickly and stored at −80 °C was found to be little, if at all, influenced by oxygen. Similar results were obtained with Serratia marcescens 8UK. Free radical studies were performed on E. coli B at −80 °C, but no free radicals were detected even after storing E. coli B for 30 days at −80 °C, −20 °C, and −10 °C. Under the last two conditions appreciable loss of viability occurred when E. coli B was frozen slowly.The results indicate that oxygen-induced loss of viability in freeze-dried and frozen and thawed Serratia marcescens 8UK and Escherichia coli B does not involve the formation of free radicals as has been suggested by other workers.

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

scholarly journals PERFIL DE SENSIBILIDADE A ANTIMICROBIANOS POR COMPONENTES DA MICROBIOTA BACTERIANA ORAL E RETAL DE PRIMATAS NÃO HUMANOS

2019 ◽  
Vol 20 ◽  
Author(s):  
Marcone Helmer Silva ◽  
Hilma Lúcia Tavares Dias ◽  
Ednaldo da Silva Filho ◽  
Sarah Raphaela Rocha de Azevedo Scalercio ◽  
Wellington Bandeira da Silva ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Serratia Marcescens ◽  
Proteus Mirabilis ◽  
Enterobacter Cloacae ◽  
Callithrix Jacchus ◽  
E Coli ◽  
Staphylococcus Xylosus

Resumo Os objetivos desta pesquisa foram identificar bactérias isoladas da cavidade oral e da ampola retal de Saimiri collinsi e Callithrix jacchus e determinar a sensibilidade a 16 antimicrobianos. Trinta indivíduos de cada espécie foram analisados e foram isoladas 136 bactérias em C. jacchus e 84 em S. collinsi. As bactérias isoladas em maior número em S. collinsi foram Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae, Raoutella ornithinolytica, Staphylococcus xylosus e Proteus mirabilis. As bactérias isoladas em C. jacchus foram K. pneumoniae, E. cloacae, E. coli, Serratia marcescens e S. xylosus na cavidade oral e ampola retal. O teste de sensibilidade mostrou que, dentre as cepas isoladas, os maiores percentuais de resistência foram observados para ampicilina, amoxicilina, cefalotina e nitrofurantoína. Na cavidade oral de ambas as espécies as cepas foram sensíveis à ceftazidima, ceftriaxona, meropenem, amicacina, levofloxacina e a sulfametoxazol/trimetoprim. Na ampola retal, as isoladas foram sensíveis à cefoxitina, ceftazidima, ceftriaxona, ertapenem, meropenem, amicacina e levofloxacina. Conclui-se que as espécies de S. collinsi e C. jacchus apresentam sua microbiota oral e retal composta por várias espécies bacterianas e que a resistência pode ser um problema no criatório, uma vez que as cepas mostraram percentuais elevados de resistência a diferentes antimicrobianos.

scholarly journals Modification by an R determinant for streptomycin of hissd phenotype in a mutant strain of Escherichia coli B

1968 ◽  
Vol 12 (2) ◽  
pp. 109-116 ◽  
Author(s):  
A. M. Molina ◽  
L. Calegari ◽  
G. Conte
Keyword(s):  
Escherichia Coli ◽  
Cell Membrane ◽  
Mutant Strain ◽  
Minimal Medium ◽  
Specific Requirement ◽  
Resistance Level ◽  
E Coli ◽  
Level Characteristic ◽  
Escherichia Coli B

When an R determinant for streptomycin is transferred into a conditionally streptomycin-dependent E. coli B mutant—which requires in minimal medium either histidine or streptomycin—the latter behaves like a histidineless strain. This phenotype modification shows that the repairing action of streptomycin is prevented. The specific requirement of the strain is not now replaced even by streptomycin concentrations up to 10000 µg/ml at which the conditionally streptomycin-dependent mutant could originally grow, and which are well beyond the resistance level characteristic of the R determinant itself. These data seem to suggest that a reduction in permeability of the cell membrane cannot be held responsible for the phenomenon observed.

scholarly journals Phenotypic Detection of Plasmid-Mediated Colistin Resistance in Enterobacteriaceae

2019 ◽  
Vol 58 (3) ◽  
Author(s):  
Edgar Gonzales Escalante ◽  
Katherine Yauri Condor ◽  
Jose A. Di Conza ◽  
Gabriel O. Gutkind
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Serratia Marcescens ◽  
Bacterial Growth ◽  
Screening Test ◽  
Colistin Resistance ◽  
Content Type ◽  
E Coli

ABSTRACT The aim of this work was to evaluate an easy-to-perform assay based upon inhibition of mobile colistin resistance (MCR) activity by EDTA. We included 92 nonrelated isolates of Enterobacteriaceae (74 Escherichia coli, 17 Klebsiella pneumoniae, and 1 Serratia marcescens). Our proposed method is based on a modification of the colistin agar-spot screening test (CAST), a plate containing 3 μg/ml colistin, by adding an extra plate of colistin agar-spot supplemented with EDTA (eCAST). Bacterial growth was evaluated after 24 h of incubation at 35°C. All the colistin-resistant isolates showed development on the CAST plates. Colistin-resistant K. pneumoniae without mcr-1 and S. marcescens also grew on the eCAST plates. In contrast, colistin-resistant MCR-producing E. coli was not able to grow in eCAST plates. The combined CAST/eCAST test could provide a simple and easy-to-perform method to differentiate MCR-producing Enterobacteriaceae from those in which colistin resistance is mediated by chromosomal mechanisms.

scholarly journals Emergence of Serratia marcescens, Klebsiella pneumoniae, and Escherichia coli Isolates Possessing the Plasmid-Mediated Carbapenem-Hydrolyzing β-Lactamase KPC-2 in Intensive Care Units of a Chinese Hospital

2008 ◽  
Vol 52 (6) ◽  
pp. 2014-2018 ◽  
Author(s):  
Jia Chang Cai ◽  
Hong Wei Zhou ◽  
Rong Zhang ◽  
Gong-Xiang Chen
Keyword(s):  
Escherichia Coli ◽  
Intensive Care ◽  
Klebsiella Pneumoniae ◽  
Serratia Marcescens ◽  
Intensive Care Units ◽  
Gel Electrophoresis ◽  
Outer Membrane Proteins ◽  
Carbapenem Resistance ◽  
E Coli ◽  
Insertional Inactivation

ABSTRACT Twenty-one Serratia marcescens, ten Klebsiella pneumoniae, and one Escherichia coli isolate with carbapenem resistance or reduced carbapenem susceptibility were recovered from intensive care units (ICUs) in our hospital. Enterobacterial repetitive intergenic consensus-PCR and pulsed-field gel electrophoresis demonstrated that all the S. marcescens isolates belonged to a clonal strain and the 10 K. pneumoniae isolates were indistinguishable or closely related to each other. The MICs of imipenem, meropenem, and ertapenem for all isolates were 2 to 8 μg/ml, except for K. pneumoniae K10 (MICs of 128, 256, and >256 μg/ml). Isoelectric focusing, PCRs, and DNA sequencing indicated that all S. marcescens isolates produced KPC-2 and a β-lactamase with a pI of 6.5. All K. pneumoniae isolates produced TEM-1, KPC-2, CTX-M-14, and a β-lactamase with a pI of 7.3. The E. coli E1 isolate produced KPC-2, CTX-M-15, and a β-lactamase with a pI of 7.3. Conjugation studies with E. coli (EC600) resulted in the transfer of reduced carbapenem susceptibility compared to that of the original isolates, and only the bla KPC-2 gene was detected in E. coli transconjugants. Plasmid restriction analysis showed identical restriction patterns among all E. coli transconjugants. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and ompK35/36 gene sequence analysis of outer membrane proteins revealed that K. pneumoniae K10 failed to express OmpK36, because of insertional inactivation by an insertion sequence ISEcp1. All these results indicate that KPC-2-producing S. marcescens, K. pneumoniae, and E. coli isolates emerged in ICUs in our hospital. KPC-2 combined with porin deficiency results in high-level carbapenem resistance in K. pneumoniae. The same bla KPC-2-encoding plasmid was spread among the three different genera.

scholarly journals Perfil de sensibilidad a los antimicrobianos de uropatógenos en un laboratorio en Macapá, Amapá, Amazonia brasileña

2021 ◽  
pp. 81-102
Author(s):  
Ítalo Fernando Penha da Silva ◽  
José Maria Henriques Serruya Júnior ◽  
Tayonara Borges Gonçalves Góes ◽  
Bruno Gomes de Noronha ◽  
Cláudio Alberto Gellis de Mattos Dias ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Serratia Marcescens ◽  
E Coli ◽  
Staphylococcus Saprophyticus ◽  
Los Grupos

Las infecciones del tracto urinario (ITU) representan un problema de salud mundial. La resistencia a los microbianos, debido a la presión selectiva de antibióticos, tiene una influencia directa en la evolución y el impacto de estas infecciones. El objetivo de este trabajo fue identificar el perfil de susceptibilidad a los antimicrobianos de los uropatógenos aislados en muestras de urocultura de un laboratorio privado en la ciudad de Macapá/AP. Se trata de un estudio cuantitativo, retrospectivo y transversal, utilizando una base de datos de laboratorio. Los datos se recopilaron de los resultados de las uroculturas con antibiograma analizados de enero a diciembre de 2019. El presente estudio evaluó 3.510 uroculturas, llevadas a cabo durante el período de estudio, de las cuales 1.269 tuvieron crecimiento bacteriano, equivalente al 36,15%. Entre los resultados positivos, encontramos la bacteria Escherichia coli (66,59%), Staphylococcus aureus (32,62%), colonias mixtas de E. coli y S. aureus (0,47%), Staphylococcus saprophyticus (0,24%) y Serratia marcescens (0,08%). El género masculino fue responsable del 16,35% (n.o 574) de las uroculturas analizadas, mientras que la población femenina fue del 83,65% (n a 2936). Al analizar la distribución de bacterias aisladas por género, los machos fueron considerados un factor protector con un 42% menos de posibilidades de presentar bacterias en la orina. La bacteria E. coli fue el patógeno predominante en estas infecciones tanto en sexos como en todos los grupos de edad.

scholarly journals Профиль чувствительности противомикробных препаратов уропатогенов в лаборатории Макапе, Амапе, бразильская Амазонка

2021 ◽  
pp. 81-102
Author(s):  
Ítalo Fernando Penha da Silva ◽  
José Maria Henriques Serruya Júnior ◽  
Tayonara Borges Gonçalves Góes ◽  
Bruno Gomes de Noronha ◽  
Cláudio Alberto Gellis de Mattos Dias ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Serratia Marcescens ◽  
E Coli ◽  
Staphylococcus Saprophyticus

Инфекции мочевыводящих путей (UTI) представляют собой всемирную проблему в области здравоохранения. Устойчивость к микробам, обусловленная селективным давлением антибиотиков, оказывает непосредственное влияние на эволюцию и воздействие этих инфекций. Цель этой работы заключалась в выявлении профиля восприимчивости к противомикробным препаратам уропатогенов, изолированных в образцах урокультуры, из частной лаборатории в городе Макапе/АП. Это количественное, ретроспективное и поперечное исследование с использованием лабораторной базы данных. Данные были собраны по результатам урокультур с помощью антибиограммы, проанализированной с января по декабрь 2019 года. В настоящем исследовании оценивалось 3510 урокультур, проведенных в течение периода исследования, из которых 1269 имели рост бактерий, что эквивалентно 36,15%. Среди положительных результатов мы обнаружили бактерии Escherichia coli (66,59%), Staphylococcus saprophyticus (32,62%), смешанные колонии E. coli e S. aureus (0.47%), Staphylococcus saprophyticus (0.24%) и Serratia marcescens (0.08%). Мужской пол был ответственен за 16,35% (n = 574) из урокультур проанализированы, в то время как женское население составило 83,65% (n = 2936). При анализе распределения бактерий, изолированных по полу, мужчины считались защитным фактором с 42% меньше шансов представить бактерии в моче. Бактерии E. палочка была преобладающим патогеном в этих инфекциях как у полов, так и во всех возрастных группах.

Free-Radical Formation during Storage of Freeze-dried Serratia marcescens

Nature ◽  
1961 ◽  
Vol 192 (4804) ◽  
pp. 776-777 ◽  
Author(s):  
R. L. DIMMICK ◽  
R. J. HECKLY ◽  
D. P. HOLLIS
Keyword(s):  
Free Radical ◽  
Serratia Marcescens ◽  
Radical Formation ◽  
Freeze Dried ◽  
Free Radical Formation
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