Multidrug resistant Salmonella typhi in asymptomatic typhoid carriers among food handlers in Namakkal district, Tamil Nadu

Purpose: To screen Salmonella typhi in asymptomatic typhoid carriers and to find out drug resistance and ability of the strains to transmit drug resistance to other bacteria Methods: Cultural characters, biochemical tests, antibiotic sensitivity test (disc diffusion), agarose gel electrophoresis, and conjugation protocols were done. Thirty five stool samples were collected from the suspected food handlers for the study. Results: Among 35 samples, (17.14%) yielded a positive result. Out of these 4 (20.0%) were women and 2 (13.33%) were men. The isolates were tested with a number of conventional antibiotics viz, amikacin, amoxicillin, ampicillin, chloramphenicol, ciprofloxacin, co-trimaxazole, rifampicin, gentamicin, nalidixic acid, ofloxacin and tetracycline. Five isolates were having the multidrug resistant character. Four (66.66%) multidrug resistant isolates were found to have plasmids, while one (16.66%) multidrug resistant isolate had no plasmid and the chromosome encoded the resistance. Only one strain (16.66%) showed single antibiotic resistance in the study and had no plasmid DNA. The molecular weights of the plasmids were determined and found to be 120 kb.The mechanism of spreading of drug resistance through conjugation process was analyzed. In the conjugation studies, the isolates having R⁺ factor showed the transfer of drug resistance through conjugation, which was determined by the development of antibiotic resistance in the recipients. Conclusion: This study shows that drug resistant strains are able to transfer genes encoding drug resistance.     

Evidence of Nosocomial Infection in Japan Caused by High-Level Gentamicin-Resistant Enterococcus faecalis and Identification of the Pheromone-Responsive Conjugative Plasmid Encoding Gentamicin Resistance

A total of 1,799 Enterococcus faecalis isolates were isolated from inpatients of Gunma University Hospital, Gunma, Japan, between 1992 and 1996. Four hundred thirty-two (22.3%) of the 1,799 isolates had high-level gentamicin resistance. Eighty-one of the 432 isolates were classified and were placed into four groups (group A through group D) with respect to the EcoRI restriction endonuclease profiles of the plasmid DNAs isolated from these strains. The 81 isolates were isolated from 36 patients. For 35 of the 36 patients, the same gentamicin-resistant isolates were isolated from the same or different specimens isolated from the same patient at different times during the hospitalization. For one other patient, two different groups of the isolates were isolated from the same specimen. Groups A, B, C, and D were isolated from 5, 14, 12, and 6 patients, respectively. The strains had multiple-drug resistance. The restriction endonuclease digestion patterns of the E. faecalis chromosomal DNAs isolated from isolates in the same group were also identical. The patients who had been infected with the gentamicin-resistant isolates from each group were geographically clustered on a ward(s). These results suggest that the isolates in each group were derived from a common source and had spread in the ward. The gentamicin-resistant isolates exhibited a clumping response upon exposure to pheromone (E. faecalis FA2-2 culture filtrate). The gentamicin resistance transferred at a high frequency to the recipient E. faecalis isolates by broth mating, and the pheromone-responsive plasmids encoding the gentamicin resistance were identified in these isolates.Enterococcus strains have become a significant cause of nosocomial infections (15, 17, 18, 22, 27). Of the members of the genus Enterococcus, E. faecalis and E. faecium are commonly isolated from humans. These two organisms account for 85 to 95 and 5 to 10% of the strains isolated from clinical infections, respectively. The Enterococcus strains isolated from clinical infections have multiple-drug resistance. The multiple-drug resistance of the enterococci provides these organisms with a selective advantage in the hospital environment. Outbreaks of nosocomial infections caused by enterococcal strains resistant to various drugs have been reported previously (9, 10, 16–18, 23, 28, 29).In a study of clinical isolates from patients in Gunma University Hospital in Gunma, Japan, enterococci were found to be the second most common among the gram-positive bacteria, after Staphylococcus aureus (unpublished data). Of the clinical E. faecalis isolates, most (about 80%) were resistant to tetracycline. Between 30 and 40% of the isolates were resistant to gentamicin or erythromycin. Ampicillin- or vancomycin-resistant strains were not isolated (14, 24). Certain E. faecalis conjugative plasmids confer a mating response to the small sex pheromones secreted by potential recipient cells (1–4, 8, 11). This mating signal induces the synthesis of a surface aggregation substance that facilitates the formation of mating aggregates and plasmid transfer (2–4, 7, 11, 25). Most (60%) of the drug-resistant strains exhibit a clumping response with a culture filtrate of a plasmid-free E. faecalis recipient strain (24), suggesting that the strains harbor a pheromone-responding plasmid.To our knowledge, there is no report concerning nosocomial infection caused by enterococci in Japan. In this report, we describe nosocomial infections in Gunma University Hospital caused by high-level gentamicin-resistant isolates of E. faecalis and isolation of the pheromone-responsive plasmids from the isolates.     

Properties and nucleotide sequence of a mitochondrial plasmid from sunflower

Summary The 1.413 circular supercoiled mitochondrial DNA plasmid P 1 from a fertile sunflower line was sequenced, and a series of 160 by tandemly repeated sequences was observed. The P1 plasmid was detected in both fertile and cytoplasmic male-sterile (CMS) lines, but in different quantities. Two other circular plasmids, P2 and P3, each 1.8 kbp in length, were shown to share common sequences with Pl. The mitochondrial plasmid P1 detected homologous sequences in the nuclear DNA of sunflower, but not in chloroplast DNA nor in main band mitochondrial DNA. RNA molecules of about 680 and 550 nucleotides were detected that were complementary to mt plasmid P1.     

Biochemical and Immunological Properties of Cytokines Conjugated to Dendritic Polymers

Here we describe a post-translational modification of SC-63032, a variant of the species restricted, multi-lineage hematopoeitic factor human interleukin-3 (hIL-3). We have made two new dendritic polymer (polyamidoamine or PAMAM dendrimers, generation 5)-SC-63032 bioconjugates. Using two distinct chemistries (one of which is novel to this work), we achieved site-specific conjugation with respect to the amino acid in the proteins ligated to the dendrimers. In both bioconjugates, conjugated cytokine maintains its ability to bind the hIL-3 alpha receptor subunit, but is significantly (about 10-fold) less potent in inducing hIL-3 dependent in vitro cell proliferation than is the free cytokine. In vivo data indicates that conjugation decreases the immunogenicity of the conjugated cytokine modestly. In the absence of pharmacokinetic or biodistribution effects associated with the bioconjugates that increase their potency in vivo (which can only be tested in a higher primate, due to the species restriction of hIL-3 and its derivatives), these immune mitigation effects may be too small to be therapeutically significant. Though unmodified PAMAM dendrimers fail to elicit an antibody response in mice, protein conjugation to dendrimers haptenizes them, and a dendrimer-specific antibody response is produced. In toto, the principal limitation of the dendrimer-cytokine bioconjugates herein is in their reduced receptor affinity and potency in vitro. Were the in vivo potency of the bioconjugates to parallel the in vitro potency of the conjugates reported here, it is likely that particular dendrimer bioconjugates could not justify their higher costs of goods relative to the parent SC-63032 molecule, though retention of SC-63032 biological activities in conjugates suggests that other cytokine-dendrimer bioconjugates may be bioactive. This is good news to the nanotechnology community, in as much as PAMAM dendrimers are among the monodisperse polymeric nanomaterials available, and these results show that they can be used successfully in conjugates to bioactive proteins.     

Genetic analysis of ad-3 mutants induced by AF-2 and two other nitrofurans in neurospora crassa

Our previous studies have shown that the nitrofurans AF-2, SQ18506, and FANFT are potent mutagens in Neurospora crassa. The genetic damage produced by these chemicals at the ad-3 region in N crassa has been characterized by a series of genetic tests. The results of these tests indicate that all three agents induce a high frequency of point mutations and probably a low frequency of multilocus deletions. A comparison of the complementation patterns among the AF-2-induced ad-3B mutants and those induced by other chemical agents indicates that the spectra of intragenic alterations induced by AF-2 in N crassa are similar to those induced by monofunctional alkylating agents.     

Linear,non-mitochondrial plasmids of Alternaria alternata

Summary Three plasmids, with sizes of 7.0 kbp, 6.8 kbp, and 5.0 kbp and designated pAal-1, pAal-2 and pAal-3 respectively, have been found in a tentoxin-producing isolate of Alternaria alternata. Exonuclease digestions show these plasmids to be linear with blocked 5 ends. Plasmid pAal-1 does not hybridize to nuclear DNA, mitochondrial DNA, or double-stranded RNA from a mycovirus found in the isolate, but does hybridize weakly to a series of linear DNAs which are not visible on gels and may include pAal-2 and pAal-3. Cellular fractionation shows that, unlike other linear fungal plasmids, these plasmids are not localized in the mitochondria. Plasmids have not been found in other tentoxin-producing isolates and there is no evidence that these plasmids have any effect on the production of tentoxin.     

Phylogenetic relationships of linear,protein-primed replicating genomes

Summary Relative phylogenetic distances were estimated for those linear plasmids for which sequencing data were available by comparing the amino-acid sequences of the putative DNA- and RNA-polymerases, and phylogenetic trees were calculated. The relationships obtained accord well with those indicated by other structural characteristics of these genetic elements. It is obvious that linear plasmids constitute a separate group of genetic traits when compared with those of the adenoviruses. However, an overall relationship to these viruses is evident. Among the linear plasmids at least two main groups can be recognized, namely the cytoplasmically and the mitochondrially localized elements.     

Comparative stability of plasmid resistance to antibioticsin vitro andin vivo

The average percentage of spontaneous plasmid-negative variants in an initial resistant population of staphylococci developingin vitro was 0.9±0.2 in broth and 1.2±0.3 in exudate; developingin vivo, in a subcutaneous suppurative inflammatory focus it was 6.3±2.0 and in the kidneys 9.5±2.6. The average percentage of spontaneous plasmid-negative variants in purulent exudatein vivo was significantly higher than in purulent exudatein vitro. The frequency of appearance of these variantsin vivo depends on the properties of the host.Gamaleya Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR G. V. Vygodchikov.) Translated from Byulleten' Éxperimental'noi Biologii i Meditsiny, Vol. 86, No. 10, pp. 452–454, October, 1978.     

Behavior of F-like plasmids in bacterial cells differing in their capacity for genetic recombination

After conjugative transfer of F-like plasmids (FB1, FB1 drd, F'-lac⁺) into cells of recipient strains ofEscherichia coli K-12 with varied recombination capacity the sensitivity of the latter to ultraviolet radiation and the degree of stability of these plasmids during treatment of the bacteria with eliminating agents were determined. The presence of any one of the F-like plasmids studied was shown to have no effect on the sensitivity of the bacterial cells to ultraviolet radiation. On the other hand, the results of a study of spontaneous and induced elimination indicate the existence of considerable differences in the behavior of these plasmids toward eliminating factors. Stability of individual F-like plasmids in cells is presumably largely dependent on genetic differences in the recA region of the host bacteria.Department of Biology and General Genetics, Patrice Lumumba Peoples' Friendship University, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. N. Zhukov-Verezhnikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 8, pp. 239–241, August, 1977.     

HBeAg真核表达质粒在293T细胞中表达的研究

目的:观察构建的真核表达质粒pJW4303/HBe在人胚肾细胞(293T)中的表达。方法:将构建好的质粒pJW4303/HBe经脂质体导入293T细胞中,分别在转染后3d、6d、9d及12d收集上清,同时对转染的细胞进行传代和冻存,传代的细胞收集上清,冻存的细胞复苏后收集上清。运用ELISA检测表达量的变化。结果:转染后3d、6d、9d及12d细胞上清液1 8稀释后HBeAg检测的OD值分别为1.047±0.093、1.494±0.112、0.998±0.087、0.678±0.124;不同时间转染传代3d后细胞上清液1 8稀释后HBeAg检测的OD值分别为0.943±0.135、1.378±0.127、0.791±0.145、0.505±0.098,不同时间转染冻存复苏3d后细胞上清液HBeAg检测的OD值分别为0.523±0.113、0.742±0.093、0.41±0.106、0.261±0.089。结论:质粒pJW4303/HBe转染293T细胞6d后HBeAg抗原表达量最高,经传代和冻存复苏后的转染细胞仍然能够表达抗原。     

The ISBT code of Ethics and the altruistic donor

Abstract The ISBT code of Ethics was first published in 1980 and aimed to define the principles and rules to be observed in the field of transfusion. Subsequently updated in 2000 it is acknowledged as a core document for the Society. The Code focusses on the importance of voluntary non-remunerated blood donation. This concept continues to be challenged particularly in the area of collection of plasma for fractionation. The background to the development of the Code is reviewed and assessed in the context of recent developments with the aim of determining whether a further revision of the Code is now needed.     

两种献血目的人群的免疫四项结果对比分析

目的 回顾性分析我院互助献血与无偿献血的血液免疫四项(HBsAg、Anti-HCV、Anti-TP、Anti-HIV)情况,为进一步评价不同献血目的人群的血液传播疾病风险提供依据.方法 对我院2015年1月至11月所采集的29935例献血者的免疫四项检测结果进行回顾性分析,根据献血者种类将献血者分为无偿献血组与互助献血组,对两组献血者的免疫四项结果的阴阳性分别进行统计分析.结果 互助献血组14940例,免疫四项结果不合格628例,在同组人数中占比4.20％.其中,HBsAg、Anti-HCV、Anti-TP、Anti-HIV不合格率分别为2.23％、0.72％、1.14％、0.10％.无偿献血组14995例,免疫四项结果不合格154例,在同组人数中占比1.03％.其中,HBsAg、Anti-HCV、Anti-TP、Anti-HIV不合格率分别为0.23％、0.42％、0.35％、0.02％.互助献血组与无偿献血组的总不合格率、HBsAg不合格率以及Anti-TP不合格率差异均具有统计学意义.结论 互助献血来源的血液安全性远低于无偿献血来源的血液.     

Titration of replication activity by increasing ARS dosage in yeast plasmids

The rep1 region of the yeast mitochondrial genome, a putative replication origin, contains a weak autonomously replicating sequence (ARS). Nucleotidesequence and deletion analyses have identified two 11-base pair ARS consensus sequences, numerous near matches to the ARS core, and a region of curvature that may contribute to ARS function. Based on the amplified nature of petite-derivative mitochondrial DNA encompassing this locus, we have constructed plasmids containing an increasing dosage of ARS elements. The rep1 ARS element can have an additive effect on plasmid stability when present either as a tandem dimer or as an unlinked pair. However, the presence of a third ARS copy does not further enhance plasmid stability. These results indicate that measurable dosage effects can be defined only in circumstances where weak ARS elements are employed, and that plasmid maintenance within yeast cells is saturable and varies among the different sequences promoting replication.     

Transfusion transmission risk of dengue viruses in an endemic area

It is believed that dengue virus (DENV) is transfusion transmittable, only a few transfusion associated cases were reported so far in spite of at least 50 million dengue infections occur globally each year. The equation for calculating DENV transfusion transmission probability was proposed following the West Nile Virus model. In consideration of reported case number, population size in the region around the designated cases, symptomatic infection rate, blood donation rate, and mosquito biological characteristics together, a relative low rate of DENV transmittable donations was presumed in a low-grade endemic area. Both the apparent clinical presentation and the relative short viremia period of DENV infection prevent dengue viruses from being a highly potential transfusion transmittable agent. The geographically based selection and donor deferral strategy seems to effectively mitigate the potential risk of DENV transfusion transmission. The costly minipooled nucleic acid test (NAT) is therefore not recommended unless for ensuring enough safe blood donations in the dengue epidemic area.     

Characterization of genetic determinants involved in antibiotic resistance in Aeromonas spp. and fecal coliforms isolated from different aquatic environments

Aeromonas spp. and fecal coliforms, two abundant and cultivable bacterial populations that can be found in water ecosystems, might substantially contribute to the spread of antibiotic resistance. We investigated the presence and spread of transposons (elements that can move from one location to another in the genome), integrons (structures able to capture and incorporate gene cassettes) and resistance plasmids in strains isolated from polluted and unpolluted water. We recovered 231 Aeromonas and 250 fecal coliforms from water samplings with different degrees of pollution (hospital sewage, activated sludge of a wastewater treatment plant, river water before and after treatment and water from an alpine lake). Sixteen Aeromonas spp. and 22 fecal coliforms carried intI, coding for the site-specific integrase of class 1 integrons, while 22 Aeromonas spp. and 14 fecal coliforms carried tnpA, the transposase gene of the Tn3-family of replicative transposons. The majority of intI and tnpA-positive strains were phenotypically resistant to at least four antibiotics. Integrons and transposons were mainly located on mobilizable plasmids.Our results did not detect common mobile structures in the two populations and therefore relativize the role played by Aeromonas spp. as vectors of antimicrobial resistance determinants between water and commensal gut bacteria.     

On antigenic properties of genetic recombinants of Escherichia coli serotypes

A study of conjugation between typed strains ofEscherichia coli belonging to different O serogroups and of conjugation between typed and untyped strains showed that the genetic determinant controlling synthesis of the O100 antigen is closely linked with the histidine locus. Among recombinants isolated from crosses between typedE. coli cells some were found to have a different serotype from that of the donor and recipient cells.Department of Biology and General Genetics, Patrice Lumumba Peoples' Friendship University. Scientific-Research Laboratory of Experimental Immunology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. N. Zhukov-Verezhnikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 8, pp. 181–182, August, 1977.     

UV hypersensitivity of yeast linear plasmids

The Kluyveromyces linear plasmids pGKL 1 and pGKL2, encoding killer activity, were efficiently cured by UV irradiation. This event was investigated in more detail by the use of the terminal protein (TP)-associated cytoplasmic linear plasmids, pJKL1 and pRKL2, with a selectable marker LEU2. This observation was compared with the UV effect on the nuclear plasmids pLS1 (telomere-associated linear form) and YCp121 (centromere-integrated circular form), indicating that the UV hypersensitivity was specific to the cytoplasmic plasmids. Using rad4 and wildtype strains of S. cerevisiae, both pJKL1 and the nuclear plasmids were found to respond not only to photoreactivation repair but also to excision repair of UV-induced DNA damage. Thus these DNA repair systems were functional for both the nuclear and cytoplasmic plasmids in yeast, and it was suggested that the UV hypersensitivity of cytoplasmic plasmids might have been caused by a defect in other repair systems or in the TP-primed replication. Possibly TP-associated Debaryomyces linear plasmids were also UV hypersensitive.This paper is dedicated to Prof. Dr. Dr. h.c. mult. Karl Esser on the occasion of the 70th anniversary (March 19, 1994) of his birthday     

Feasibility and safety of multicomponent apheresis donation

Background and Objectives Modern apheresis devices offer the possibility to collect blood components that are well standardized, as compared with those available with manual whole blood donations. Recent technologic advances in multicomponent donation have made possible the development of systems that can collect different blood components from the same donor during one apheresis session. Red blood cells (RBCs) can be concurrently collected with plasma or platelets (PLTs). Materials and Methods A PLT yield of ≥2 × 10¹¹ per unit according to European guidelines can be targeted by the algorithm of the blood cell separators after entering donor specific parameters such as body weight, height and blood counts. Furthermore, two units of RBCs can also be collected during one apheresis session provided that the donor fulfils the eligibility criteria for that procedure. Results The haemoglobin content of apheresed RBCs after addition of additive solution is higher than the minimal European requirement of whole blood derived RBCs of 40 g per unit due to standardization. Automated blood cell separators permit predictable collection of blood components with consistent yields and volumes. Repeat apheresis donors accept multicomponent donation and consent to concurrent component collection in >90% of the procedures. The results of a national survey showed that approximately 75% were willing to give an additional RBC unit four times per year. This allows blood centres to increase the number of units colleted at low extra costs. Collecting an additional RBC unit in plateletpheresis causes extra costs of approximately 20€ for disposables and work load compensating the production costs with respect to the selling price. The incidence of acute adverse events in multicomponent apheresis was reported with less than 1%. Small, female donors with lower pre-donation haematocrit were at higher risk for adverse events, especially when RBCs were collected. Double unit RBC collection showed to be safe if special eligibility criteria were respected. Conclusion Previous definitions of blood component yield and volume as well as the flexibility to collect those multicomponents allow the blood centre to collect those components that maximize donors’ contribution and to meet the demands of its area hospitals for blood components. Blood transfusion services are progressively increasing their reliance on apheresis technology to optimize the number of blood components collected per donor visit and to reduce the number of donors a patient is exposed to. The use of these systems has shown at the same time that multicomponent donations have been well tolerated by the donors and are cost-effective.