Positive Microbes Research Articles

In vitro comparative study of Bougainvillea spectabilis “stand” leaves and Bougainvillea variegata leaves in terms of phytochemicals and antimicrobial activity

AimTo study the qualitative analysis of phytochemicals and antibacterial activity of the ethanolic and methanolic extracts of Bougainvillea spectabilis and Bougainvillea variegata leaves. MethodsPhytochemical constituents were determined qualitatively by the Harborne method, while antimicrobial activities were determined by measuring the zone of inhibition on Mueller Hinton Agar. ResultsThe maximum inhibitory effects were obtained against the Gram positive microbe Staphylococcus aureus for the methanolic extracts of both B. spectabilis [(28.54 ± 0.18) mm] and B. variegata [(21.97 ± 0.06) mm]. The Gram negative microbes Proteus vulgaris [(16.00 ± 0.15) mm] and Serratia marcescens [(16.00 ± 0.06) mm] gave maximum inhibitory effects for the ethanolic extracts of B. variegata, while Salmonella typhimurium [(17.26 ± 0.12) mm] gave a maximum zone of inhibition for the methanolic extract of B. spectabilis. No inhibitory effects were observed for the extracts of B. spectabilis or B. variegate against Enterococcus faecalis, Vibro cholera or Klebsiella pneumoniae. ConclusionBoth B. spectabilis and B. variegata possess significant antimicrobial activity that, following additional studies, could replace commercially known antibiotics.

Symptoms and Risk Factors Associated with First Urinary Tract Infection in College Age Women: A Prospective Cohort Study

We identified epidemiological risk factors for the initial urinary tract infection in females of college age compared to age matched controls. We performed a prospective cohort study from July 2001 to January 2006 at the student health care facility at our institution. A total of 180 women experiencing a first urinary tract infection were compared to 80 asymptomatic women with no urinary tract infection history who served as controls. Urinalysis and urine culture were done at study enrollment. Questionnaires were used to obtain information on clinical symptoms and behaviors, including sexual and dietary practices, and alcohol consumption. Logistic regression was performed to identify potential risk factors in women who presented with an initial urinary tract infection compared with controls. Principal component analysis was then done to identify key sexual activity variables for multiple regression models. Urinary frequency and urgency were the most common urinary tract infection symptoms. Recent sexual activity was a significant risk factor for urinary tract infection with vaginal intercourse (p = 0.002) and the number of sexual partners in the last 2 weeks (p <0.001) as the 2 primary variables. Alcohol consumption was associated with 2 of the 3 main principal components of sexual activity. Caffeinated beverage consumption also increased the risk of urinary tract infection (p <0.04). Escherichia coli was the predominant pathogen isolated, followed by urease positive microbes. Recent sexual activity, the frequency of that activity and the number of sexual partners pose an increased risk of urinary tract infection. Alcohol consumption frequency and amount correlated with these behaviors.

Phosvitin Plays a Critical Role in the Immunity of Zebrafish Embryos via Acting as a Pattern Recognition Receptor and an Antimicrobial Effector

How fish embryos that develop externally survive microbial attacks is poorly understood. Here, we clearly demonstrated that the embryo extract of zebrafish and its early embryo both displayed antimicrobial activity against microbes, including pathogenic Aeromonas hydrophila, and phosvitin (Pv), a nutritional protein abundant in eggs, was related to this antimicrobial activity. We also showed that recombinant Pv (rPv) acted as a pattern recognition receptor capable of recognizing the microbial signature molecules LPS, lipoteichoic acid, and peptidoglycan, as well as binding the Gram-negative and -positive microbes Escherichia coli, A. hydrophila, and Staphylococcus aureus and functioned as an antimicrobial agent capable of killing the microbes. Furthermore, we revealed that its C-terminal 55 residues (Pt5) with the functional sites Arg(242) and Ala(201)/Ile(203) were indispensable for Pv antimicrobial activity. Importantly, microinjection of rPv or Pt5 into early embryos significantly enhanced their resistance to A. hydrophila challenge, and this enhanced bacterial resistance was markedly reduced by co-injection of anti-Pv antibody plus rPv (or Pt5) but not by injection of anti-actin antibody plus rPv. Moreover, the generated mutants with in vitro antimicrobial activity, when injected into the embryos, could also promote their resistance to A. hydrophila, but those without in vitro antimicrobial activity could not. It is thus proposed that Pv participates in the protection of early embryos against pathogenic attacks via binding and disrupting potential pathogens. This work also opens a new way for the study of the immunological roles of yolk proteins in oviparous animals that rely on yolk proteins for embryonic development.

Nadifloxacin, an antiacne quinolone antimicrobial, inhibits the production of proinflammatory cytokines by human peripheral blood mononuclear cells and normal human keratinocytes

Acne vulgaris is a chronic inflammatory disease involving colonization of Propionibacterium acnes (P. acnes), activation of neutrophils and lymphocytes. Circumstantial evidence suggests that antigen-independent and -dependent immune responses against P. acnes are involved in the pathogenesis of inflammatory acne. Epidermal keratinocytes are also suggested to be involved in initiation and progression of cutaneous inflammation. Nadifloxacin, a fluorinated quinolone, has potent antimicrobial activities against Gram-negative and -positive microbes and is used to treat multiple inflamed acne lesions. However, its effect on immune conferring cells such as mononuclear cells and keratinocytes has not been examined. To evaluate the possible involvement of potential anti-inflammatory activity of nadifloxacin in its therapeutic effect on inflammatory acne, we examined the effects of nadifloxacin, in comparison with other antibiotics used to treat acne vulgaris, on cytokine production by human peripheral blood mononuclear cells (PBMC) and keratinocytes. Cytokine production by PBMC was determined after treatment with heat-killed P. acnes in the presence or absence of antimicrobials using a real-time PCR and ELISA. Cultured human epidermal keratinocytes were stimulated by IFN-gamma plus IL-1beta and the effects of antimicrobials were examined by using ELISA. Nadifloxacin as well as macrolide antibiotics and clindamycin inhibited IL-12 and IFN-gamma production by PBMC stimulated by heat-killed P. acnes. The drug also inhibited the IL-1alpha, Il-6, IL-8 and GM-CMS production by keratinocytes treated with IFN-gamma plus IL-1beta. Inhibitory effects of nadifloxacin to activate T cells and keratinocytes may be involved at least in part in the mechanism of its therapeutic effect against inflammatory acne.

Full sequence and characterization of two insect defensins: immune peptides from the mosquito Aedes aegypti.

We report the complete amino acid sequence and biological activity of two immune peptides, from the yellow fever mosquito Aedes aegypti, that are induced in response to infection. Both peptides display biological activity against the Gram positive microbe Micrococcus luteus and substantial sequence homology to insect defensins, small heat-stable, antibiotic peptides previously described from several non-vector insects. These mosquito peptides, designated Ae. aegypti defensins A and B, are isoforms. Defensin B is the most abundant antibacterial peptide in this species whereas defensin A is much less abundant and carries two amino acid substitutions compared to defensin B, making it more basic in character. Apparent convergence between isoforms from Ae. aegypti and the fleshfly Phormia terranovae is discussed. The synergistic activity previously described between Ae. aegypti immune haemolymph and lysozyme is not caused by these peptides because synergy occurred only at concentrations far outside the physiological range seen in Ae. aegypti.

Polarization studies of pure Fe in the presence of hydrogenase positive microbes-II. Photosynthetic bacteria and microalgae

Experiments with resting cell suspensions of eight species of hydrogenase positive microbes have shown that the organisms are able to utilize cathodic hydrogen and so initiate “classical” microbial corrosion. The results are discussed in relation to the natural habitat of the organisms and their ability to utilize atmospheric nitrogen.

The study of bacteriostatic and chemotherapeutic action of the antituberculous preparation 1314 and its chlorhydrate

The authors conducted an experimental study of the bacteriostatic and chemotherapeutic effect of the autituberculous preparation 1314 (thiamido-α-ethylisonicotinic acid) and its hydrochloride. The preparation appeared to be nonactive with respect to gram positive and gram negative microbes in vitro. However, it possesses a high bacteriostatic activity with respect to theMycobacteriumtuberculosis including certain strains resistant to other antibiotics. The chemotherapeutic effect of the preparation was checked on white mice with experimentally induced hematogenous tuberculosis. Daily administration of the preparations per os (1–2 mg per mouse) retards the development of tuberculosis. The same results were obtained with administration of the hydrochloride of the 1314 per os and subcutaneously in the dose of 2 mg per mouse.