Isolation and characterization of a conditional replication mutant of the antibiotic resistance factor R1 affected in the gene of the replication protein RepA

1989 ◽  
Vol 217 (1) ◽  
pp. 111-117 ◽  
Author(s):  
Sagrario Ortega ◽  
Gertrudis de Torrontegui ◽  
Ramón Díaz
2018 ◽  
Author(s):  
Carolina M. Mizuno ◽  
Tiffany Luong ◽  
Robert Cedarstrom ◽  
Mart Krupovic ◽  
Laurent Debarbieux ◽  
...  

AbstractEnteropathogenic Escherichia coli (EPEC) is a major etiology for diarrheal diseases among children. Antibiotics, when used appropriately, are effective; however, their overuse and misuse has led to the rise of antibiotic resistance worldwide. Thus, there are renewed efforts into the development of phage therapy. Due to the drawbacks of EPEC in vivo models, a surrogate is the mouse-restricted gut pathgoen Citrobacter rodentium. In this study, two new phages CrRp3 and CrRp10, which infect C. rodentium, were isolated and characterized. CrRp3 was found to be a new species within the genus Vectrevirus and CrRp10 is a new strain within the genus Tequatrovirus. Neither phage carries known genes associated with bacterial virulence, antibiotic resistance, or lysogeny. CrRp3 and CrRp10 appear to have independently evolved from E. coli phages. CrRp3 appears to be the more ‘potent’ being 24x more likely to find a host cell and has a shorter lytic cycle, while CrRp10 at MOI 0.001 was able to maintain bacterial density below the limit of detection after 18 h. We found that hypoxia (5% O2 and 5% CO2) inhibited CrRp3 ability to reverse exponential bacterial growth. It is unclear whether the subtle characteristic differences between CrRp3 and CrRp10 will influence treatment efficacy in future phage therapy in vivo investigations.


1985 ◽  
Vol 31 (4) ◽  
pp. 339-345 ◽  
Author(s):  
Takayuki Hoshino ◽  
Takayuki Ikeda ◽  
Hiroyuki Narushima ◽  
Noboru Tomizuka

Four antibiotic-resistance plasmids isolated from thermophilic bacilli were characterized in detail. Three tetracycline-resistance (Tcr) plasmids were designated as pTHT9 (7.7 kilobases (kb)), pTHT15 (4.5 kb) and pTHT22 (8.4 kb). From the results of restriction endonuclease analysis and the subsequent Southern hybridization, these were found to possess extensive genetic homology in the regions that include the replication origin and the Tcr gene. Detailed restriction maps of the smallest Tcr plasmid pTHT15 and a kanamycin-resistance (Kmr) plasmid pTHN1 (4.8 kb) were constructed. The positions of antibiotic-resistance loci and regions essential for plasmid replication were determined by cloning plasmid fragments in Bacillus subtilis. These four plasmids were found to replicate and express the resistance genes stably in both B. subtilis and B. stearothermophilus.


2019 ◽  
Vol 49 (10) ◽  
Author(s):  
Gustavo Luis de Paiva Anciens Ramos ◽  
Janaína dos Santos Nascimento

ABSTRACT: Goat’s milk has been suggested as an alternative to cow’s milk, being a better digestible and hypoallergenic option. However, the presence of contaminating bacteria may significantly affect the safety of the product. In this research, we reported the isolation and characterization of Acinetobacter spp. isolates from raw goat milk samples purchased in the state of Rio de Janeiro, Brazil. Twenty-one samples were analyzed and ten isolates of Acinetobacter spp. were obtained. Six were identified as A. guillouiae, three as A. ursingii, and one as A. bereziniae. These isolates were characterized and eight showed proteolytic activity, seven showed lipolytic activity, and five isolates were able to produce both enzymes. None of the isolates was biofilm producer. However, when the production of antibiotic resistance enzymes KPC and ESBL were investigated, all isolates presented ESBL-positive phenotype, while eight (80%) were KPC-positive. This research, therefore, demonstrated that raw goat’s milk can also be a source of Acinetobacter spp., which can produce important thermostable deteriorating enzymes and may play a role of reservoirs of antibiotic resistance genes.


2013 ◽  
Vol 7 (2) ◽  
pp. 24-30
Author(s):  
Wasan W. Al-Bassam ◽  
Abdul-Kareem Al-Kazaz

A total of one hundred five samples were collected from hospitals of Baghdad city during the period from 10/12/2008 to 15/3/2009. These clinical samples included: urine (50) wound swabs (25), sputum (20), and ear swabs (10). These samples were collected from the Baghdad hospital/ Teaching Laboratories, and Al-Yarmook Hospital/ Teaching Laboratories. Twenty six isolates of Proteus mirabilis were characterized according to the morphology and microscopic characteristics, along with the biochemical and confirmatory APi 20 E tests. These isolates were obtained from: urine (19), wound swabs (6), ear swabs (2), and sputum (1). The twenty selected isolates were tested for resistance against ten antibiotics and only urine samples were tested for nalidixic acid and nitrofurantoin resistance. It was shown that there were differences in the antibiotic resistance of isolates. High resistance to nitrofurantoin and ampicillin were found among isolates as (100%) and (75%) respectively while the resistance of Proteus isolates to trimethoprin /sulphamethazol, were (65%). This study also showed that resistance of isolates to gentamicin, ciprofloxacin, ceftazidime, pipracillin, cefotaxime, nalidixic acid azteronam, imipenem and amikacin were (50, 40, 40, 40, 35,27, 20,15, 5)% respectively.


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