scholarly journals Conjugative transfer of R-plasmids from Streptococcus faecalis to Staphylococcus aureus.

1982 ◽  
Vol 22 (2) ◽  
pp. 204-207 ◽  
Author(s):  
D R Schaberg ◽  
D B Clewell ◽  
L Glatzer
2017 ◽  
Vol 199 (8) ◽  
Author(s):  
Emily A. Sansevere ◽  
Xiao Luo ◽  
Joo Youn Park ◽  
Sunghyun Yoon ◽  
Keun Seok Seo ◽  
...  

ABSTRACT ICE6013 represents one of two families of integrative conjugative elements (ICEs) identified in the pan-genome of the human and animal pathogen Staphylococcus aureus. Here we investigated the excision and conjugation functions of ICE6013 and further characterized the diversity of this element. ICE6013 excision was not significantly affected by growth, temperature, pH, or UV exposure and did not depend on recA. The IS30-like DDE transposase (Tpase; encoded by orf1 and orf2) of ICE6013 must be uninterrupted for excision to occur, whereas disrupting three of the other open reading frames (ORFs) on the element significantly affects the level of excision. We demonstrate that ICE6013 conjugatively transfers to different S. aureus backgrounds at frequencies approaching that of the conjugative plasmid pGO1. We found that excision is required for conjugation, that not all S. aureus backgrounds are successful recipients, and that transconjugants acquire the ability to transfer ICE6013. Sequencing of chromosomal integration sites in serially passaged transconjugants revealed a significant integration site preference for a 15-bp AT-rich palindromic consensus sequence, which surrounds the 3-bp target site that is duplicated upon integration. A sequence analysis of ICE6013 from different host strains of S. aureus and from eight other species of staphylococci identified seven divergent subfamilies of ICE6013 that include sequences previously classified as a transposon, a plasmid, and various ICEs. In summary, these results indicate that the IS30-like Tpase functions as the ICE6013 recombinase and that ICE6013 represents a diverse family of mobile genetic elements that mediate conjugation in staphylococci. IMPORTANCE Integrative conjugative elements (ICEs) encode the abilities to integrate into and excise from bacterial chromosomes and plasmids and mediate conjugation between bacteria. As agents of horizontal gene transfer, ICEs may affect bacterial evolution. ICE6013 represents one of two known families of ICEs in the pathogen Staphylococcus aureus, but its core functions of excision and conjugation are not well studied. Here, we show that ICE6013 depends on its IS30-like DDE transposase for excision, which is unique among ICEs, and we demonstrate the conjugative transfer and integration site preference of ICE6013. A sequence analysis revealed that ICE6013 has diverged into seven subfamilies that are dispersed among staphylococci.


1986 ◽  
Vol 7 (12) ◽  
pp. 582-585 ◽  
Author(s):  
Capt Robert A. Johnson ◽  
Capt Robert A. Zajac ◽  
Maj Martin E. Evans

AbstractWe identified 29 episodes of suppurative thrombophlebitis in 27 patients admitted to a large general hospital between May 1980 and May 1984. In 25 patients, the intravenous cannulae had been in place for more than 3 days. Streptococcus faecalis, Pseudomonas aeruginosa or one of the Enterobacteriaceae were implicated in 14 patients. All these patients had recently undergone abdominal surgery or had a major intraabdominal inflammatory process at the time they developed thrombophlebitis. The remaining 13 patients were infected with Staphylococcus aureus, other grampositive cocci or Candida species. Only two of these had an active abdominal process at the time of their infection (x2 = 16.08, P<0.001). There is an apparent association between phlebitis caused by enteric organisms and active intra-abdominal pathology. There were two deaths related to delayed or deferred surgery. Suppurative thrombophlebitis is a lethal, preventable nosocomial infection that requires urgent surgical intervention.


1986 ◽  
Vol 49 (3) ◽  
pp. 233-235 ◽  
Author(s):  
PATRICIA HAGGERTY ◽  
NORMAN N. POTTER

Studies were made to compare the growth and death of Staphylococcus aureus, Streptococcus faecalis and Escherichia coli in skim milk concentrated by ultrafiltration to that in unconcentrated skim milk. Skim milk was volume concentrated to 2× in laboratory-scale stirred UF cells. Behavior of the organisms was analyzed in four inoculated milk samples: 2× retentate, 1× water-diluted retentate, milk equivalent (retentate plus permeate) and unconcentrated skim milk. Growth of each organism and of total aerobes did not vary in the four milk samples at either 7 or 13°C. For S. faecalis and E. coli, D-values for samples heated to 62.7°C did not significantly differ in the four milk samples (p&gt;0.01). The D-value of S. aureus in water-diluted retentate was slightly but significantly lower than those in the other three milk samples (p&lt;0.01), possibly due to the lowered lactose level in this sample.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Priya Srivastava ◽  
D. K. Upreti ◽  
T. N. Dhole ◽  
Apurva K. Srivastava ◽  
Meghanand T. Nayak

Context.Usnea ghattensisG. Awasthi (Usneaceae) endemic fruticose lichen found growing luxuriantly in Northern Western Ghats of India, it also contains Usnic acid as a major chemical and tested against some human pathogenic bacteria.Objective. To explore antimicrobial properties ofUsnea ghattensisagainst some human pathogenic bacteria.Materials and Methods. The lichen was extracted in acetone, methanol, and ethanol.In vitroantimicrobial activity was tested initially byKirby-Bauertechnique of disc diffusion method and was confirmed by minimum inhibitory concentration using Broth microdilution method according to the NCCLS guidelines.Results. Ethanol extract was most effective againstBacillus cereusandPseudomonas aeruginosawith a zone of inhibition 29.8 ± 0.6 mm and 12.3 ± 0.5 mm diameters at a concentration of 0.2 mg/mL. Acetone and methanol extract demonstrated almost similar activity againstStaphylococcus aureusand the zone of inhibition was 24.6 ± 0.5 and 24.7 ± 0.4 mm. Only methanol extract was showing activity againstStreptococcus faecaliswith a 13.5 ± 0.8 mm zone. MIC value noted againstStaphylococcus aureusandStreptococcus faecaliswas 6.25 μg/mL and 25 μg/mL, whereas againstBacillus cereusandPseudomonas aeruginosa, MIC calculated was 3.125 μg/mL and 200 μg/mL, respectively.Conclusion. The present study demonstrates the relatively higher activity of this lichen against not only gram (+) but significantly also against gram (−) bacteria. This indicates that this lichen might be a rich source of effective antimicrobial agents.


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