[Native-valve endocarditis produced by Lactobacillus casei sub. rhamnosus refractory to antimicrobial therapy]. / Endocarditis de valvula nativa producida por Lactobacillus casei sub, rhamnosus refractaria al tratamiento con antimicrobianos.

Lactobacillus endocarditis is a rare infection. In fact, only 42 cases have been described in the literature from 1938 up to date. In only 17 previously reported cases have patients been cured with medical therapy alone. Although infections produced by Lactobacillus spp, have been described in our country, none of them included endocarditis. We report herein a case of endocarditis due to a vancomycin-resistant strain of Lactobacillus casei sub. rhamnosus in a 29-year-old man with prolapse of the mitral valve. He required surgical replacement of his valve because of the poor response to antimicrobial therapy with penicillin and gentamicin. The patient displayed a successful clinical outcome, with no evidence of recurrence along the subsequent 2 years. We point out the need to accurately identify Lactobacillus spp. in isolates from blood cultures of patients with endocarditis, since these bacteria may often be mistaken for other species more frequently associated to this infection, which usually respond to conventional antimicrobial therapy. Furthermore, we suggest that early surgical replacement should be considered when lactobacillus endocarditis is diagnosed.

[Identification of protein products of the operon for leukocytosis (lymphocytosis)-stimulating factor from Bordetella pertussis cloned in Escherichia coli]. / Identifikatsiia belkovykh produktov operona leikotsitoz (limfotsitoz)-stimuliruiushchego faktora Bordetella pertussis, klonirovannogo v Escherichia coli.

The hybrid plasmid pRH119 was constructed on the basis of vector plasmid pUC19 and shown to carry Bordetella pertussis PT operon in the same transcriptional orientation with the lac-promoter of the vector plasmid. Expression of PT genes in E. coli cells harbouring pRH119 was not registered. Weak expression of PT genes was found by immunoscreening of recombinant clones in situ with antiserum against PT when PT genes were put closer to lac-promoter. 0.95 kb SalGI fragment was deleted from pRH119. The derivative plasmid pRH122 was digested by SalGI and the ends were polymerized to "blunt" by polIK and ligated. The obtained plasmid pRH122K was deleted for 40 bp in XbaI site by Bal31 deletion. The lysate of E. coli cells harbouring the resulting plasmid pRH134 passed through Sepharose 4B with covalently bound immunoglobulins from antiserum against PT. The eluted protein contains S2 multimers identified by immunoblotting. The experiments with CHO-cells and active mice protection have shown the absence of S2 multimers protectiveness.

[Cloning and gene expression of the leukocytosis (lymphocytosis) stimulating factor of Bordatella pertussis in Escherichia coli by bringing the PT genes close to the lactose promoter of plasmid pUC19]. / Klonirovanie i ékspressiia genov leikotsitoz (limfotsitoz)-stimuliruiushchego faktora Bordetella pertussis v Escherichia coli putem priblizheniia genov k laktoznomu promotoru plazmidy pUC19.

The 4.7 Kb EcoRI-fragment of phase I B. pertussis 475 (serovar 1.2.3.) chromosome carrying all five genes of the pertussis toxin (PT) operon was cloned on plasmid pUC19 in E. coli. The resulting hybrid plasmid pRH119 contained the PT operon in the same orientation of transcription as the lac promoter of plasmid pUC19. Nevertheless, the expression of the PT operon was not observed even after induction with isopropyl thio-beta-D-galactopyranoside (IPTG), which suggested either the inability of the PT operon to work in E. coli, or the presence of a transcription terminator between the lac promoter and the PT operon in plasmid pRH119. The expression was determined by the incubation of the clones harboring plasmid pRH119 with antiserum to PT and their subsequent in situ treatment with 125I-labeled protein A. Three deletion variants of plasmid pRH119 were constructed with the aim of approaching the PT genes to the lac promoter: pRH121 (the 0.45 Kb KpnI-fragment deleted), pRH122 (the 0.95 Kb SalGI-fragment deleted) and pRH123 (the 1.35 Kb XbaI-fragment deleted). In all these cases different levels of expression were observed (but only in the presence of IPTG). Site KpnI in the 4.7 Kb fragment was found to be localized in the -57 b. p. region in relation to the PT promoter, i. e. to lie, seemingly, in the promoter zone; for this reason, the expression of the PT genes in plasmid pRH121 proved the existence of a transcription terminator between the lac promoter and the PT operon in plasmid pRH119.(ABSTRACT TRUNCATED AT 250 WORDS)

[Detection of the gene sequences of the leukocytosis (lymphocytosis)-stimulating factor of Bordetella pertussis in Bordetella parapertussis and Bordetella bronchiseptica by using molecular hybridization]. / Obnaruzhenie posledovatel'nostei genov leikotsitoz (limfotsitoz)-stimuliruiushchego faktora Bordetella pertussis u Bordetella parapertussis i Bordetella bronchiseptica s pomoshch'iu molekuliarnoi gibridizatsii.

The 4.7 Kb EcoRI-fragment of phase I B. pertussis 475 (serovar 1.2.3) chromosome DNA carrying the pertussis toxin (PT) operon was cloned on vector plasmid pUC19 in Escherichia coli. Three fragments (1.14 Kb KpnI-PstI, 1.27 Kb PstI-PstI, and 0.96 Kb PstI-PstI) were obtained from the resulting hybrid plasmid, coded pRH119, by electrophoretic techniques and used as a combined molecular probe for analysis of the EcoRI-digested and PstI-digested chromosomal DNA of B. pertussis strain 475 in phase I, B. pertussis in phase IV, B. parapertussis strains 504 and 17903, B. bronchiseptica strain 214, and B. parapertussis strain 17903 (a convertant obtained by means of B. pertussis phage 134), as well as B. pertussis phage 134. Southern blot hybridization under the conditions of 100% DNA-DNA homology showed the presence of DNA sequences characteristic of the PT operon in all cases except the DNA of phage 134; moreover, the use of the above-mentioned probe made it possible to hybridize all EcoRI-fragments of chromosomal DNA, having the same molecular size (4.7 Kb). Consequently, the PT genes in the above Bordetella species were mapped in identical loci.(ABSTRACT TRUNCATED AT 250 WORDS)

[Cloning and the expression of the hemolysin gene of Leptospira pomona pomona in Escherichia coli]. / Klonirovanie i ékspressiia gena gemolizina Leptospira pomona pomona v Escherichia coli.

The library of Leptospira pomona genes was obtained on phage vector AL 47.1. From this library a recombinant phage carrying the hemolysin gene was selected. The DNA fragment (7.7 kb) of this phage containing the hemolysin gene was subcloned on plasmid pUC19. E. coli clones with hybrid plasmid pDR7 were shown to be hemolytic, but the secretion of hemolysin by E. coli into the culture medium was not observed.

All species of the genus Bordetella contain genes for pertussis toxin of Bordetella pertussis.

A molecular probe for the PT-operon of B. pertussis hybridized with 4.7 Kb EcoRI-fragments of chromosomal DNAs of B. pertussis strain 475 phase I, phase IV, B. parapertussis strains 504 and 17903, B. bronchiseptica strain 214, B. parapertussis strain 17903-convertant of B. pertussis phage 134 but not with phage 134 DNA under stringent conditions of DNA-DNA hybridization. This fact indicates the presence of PT-genes in all Bordetella species. Since there is no production of PT in B. parapertussis and B. bronchiseptica, a presence of regulatory mutations in the PT-operon or absence of the functionally active vir-gene product in these species is suggested.