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1.
Pseudomonas aeruginosa is an opportunistic pathogen of immunocompromised hosts. In cystic fibrosis (CF), P. aeruginosa causes acute and chronic lung infections that result in significant morbidity and mortality. P. aeruginosa possesses several traits that contribute to its ability to colonize and persist in acute and chronic infections. These include
high resistance to antimicrobials, ability to form biofilms, plethora of virulence products, and metabolic versatility. In
P. aeruginosa, a cell-to-cell communication process termed quorum sensing (QS) regulates many of these factors that contribute to its pathogenesis.
Recent evidence suggests that the CF lung environment presents a specialized niche for P. aeruginosa. The relationship of P. aeruginosa QS, biofilm formation, and the CF lung environment is discussed. 相似文献
2.
In this review, we define the biofilm process as a type of intercellular bacterial communication. We present up-to-date data
on the structure of the Pseudomonas aeruginosa biofilm matrix and genetic mechanisms regulating its formation, discuss processes involved in active or passive rejection
of the biofilm bacteria that promotes their spreading and attaching to new surfaces, and stress the complexity and chain character
of reactions associated with biofilm formation. 相似文献
3.
D. H. Limoli J. Yang M. K. Khansaheb B. Helfman L. Peng A. A. Stecenko J. B. Goldberg 《European journal of clinical microbiology & infectious diseases》2016,35(6):947-953
Cystic fibrosis-related diabetes (CFRD) patients suffer from accelerated rates of pulmonary decline compared to cystic fibrosis (CF) patients with normal glucose tolerance (NGT). However, the mechanisms underlying this difference are unknown. While CFRD is associated with increased respiratory infections, a link between infection and enhanced pulmonary dysfunction remains unclear. The development of glucose intolerance is spectral, resulting in impaired glucose tolerance (IGT) prior to the diagnosis of CFRD. Inclusion of IGT patients within the NGT group may diminish the ability to identify correlations with CFRD. With this in mind, this study aimed to determine if the association between CFRD and respiratory infections is correlated with pulmonary decline. Respiratory cultures from 234 CF patients with confirmed diagnosis of NGT or CFRD were analyzed to measure rates of infection, focusing on the two most prevalent bacteria in CF, Staphylococcus aureus and Pseudomonas aeruginosa. Infection status was correlated with pulmonary function and confounding clinical variables including age, gender, blood glucose levels, and CF transmembrane conductance regulator (CFTR) phenotype were considered in multivariate analyses. CFRD patients, particularly those with extremely high blood glucose levels, were more likely than NGT patients to be co-infected with S. aureus and P. aeruginosa, compared to infection with only one pathogen. Co-infection was associated with decreased lung function and increased frequency of pulmonary exacerbations, even after adjustment for confounding variables. Alterations in the microbial community composition, as opposed to the presence of a single pathogen, may account for greater pulmonary decline in CFRD patients. 相似文献
4.
L.?de?Souza Gon?alves R.?Souto A.?P.?V.?Colombo 《European journal of clinical microbiology & infectious diseases》2009,28(11):1335-1342
This study compared the frequency of Helicobacter pylori, Enterococcus faecalis, and Pseudomonas aeruginosa in the subgingival microbiota of HIV-seropositive and HIV-seronegative subjects with periodontitis or clinically healthy
periodontal tissues. Fifty-four subjects were distributed into two HIV-seropositive groups (chronic periodontitis [HCP = 13]
and periodontal health [HH = 10]) and two HIV-seronegative groups (chronic periodontitis [CP = 17] and periodontal health
[H = 14]). The detection of bacterial species was carried out by polymerase chain reaction (PCR). CP patients showed significantly
more periodontal destruction, inflammation, and supragingival plaque than HCP patients (P < 0.05). All species were detected at a higher prevalence in CP and HCP than H individuals (P < 0.01). In the HIV groups, H. pylori was significantly more prevalent in periodontitis compared to healthy patients (P < 0.01). A higher frequency of E. faecalis and P. aeruginosa was observed in the subgingival biofilm of HH than H subjects (P < 0.01). Moreover, E. faecalis was detected significantly more often in HIV-seropositive compared to HIV-seronegative patients, regardless of periodontal
status (P < 0.01). These data indicate that H. pylori is frequently detected in the subgingival microbiota of periodontitis subjects. In contrast, HIV-seropositive patients with
either periodontitis or periodontal health present a high prevalence of E. faecalis. 相似文献
5.
Galba truncatula snails were experimentally infected with either of two different isolates of Fasciola gigantica, originating from Egypt or China, to determine the influence of these isolates on the characteristics of snail infections. The survival rates of G. truncatula on day 30 post-exposure were 90.0% and 60.2% in the Egyptian and Chinese groups, respectively. The frequency of cercaria-shedding snails within the Egyptian group was 79.8%, whereas in the Chinese group it was 22.4%. The parasite origin had a significant effect on the durations of the prepatent and patent periods. The mean number of cercariae shed from the Egyptian group was significantly greater than that shed from the Chinese group (a mean of 275.5 per cercaria-shedding snail compared with 29.0). These results could be explained by the fact that G. truncatula might be a natural intermediate host for F. gigantica in Egypt, and the greater adaptability of the Egyptian miracidia of F. gigantica to unusual snail hosts. These results demonstrate the influence of the geographic origin of the parasite on the success of trematodes infecting snails. 相似文献
6.
L. Vettoretti N. Floret D. Hocquet B. Dehecq P. Plésiat D. Talon X. Bertrand 《European journal of clinical microbiology & infectious diseases》2009,28(10):1217-1222
The aim of this study was to describe the molecular epidemiology and the mechanisms of resistance to β-lactams of emerging
extensive-drug-resistant Pseudomonas aeruginosa (XDRPA) in a tertiary-care university hospital over a three-year period. Analysis included antimicrobial susceptibility profiling
and pulsed-field gel electrophoresis (PFGE). Resistance mechanisms to β-lactams were identified: production of naturally occurring
and acquired β-lactamases, overproduction of MexAB-OprM and MexXY efflux systems and loss of porin OprD were assessed. Eighteen
patients were colonised or infected with XDRPA which remained susceptible to colistin and, to a lesser extent, to rifampicin.
β-lactam resistance was, in most cases, due to the overproduction of AmpC, overproduction of the MexXY efflux system and loss
of porin OprD. One isolate produced the class D extended-spectrum oxacillinase (OXA-ESBL) Oxa-28, but none produced metallo-β-lactamase
(MBL) or class A extended-spectrum β-lactamase (ESBL). The XDRPA clustered in eight PFGE patterns and both the acquisition
and loss of resistance determinants was observed within a single clone during its spread. The emergence of XDRPA isolates
in our university hospital has been characterised by genotypic heterogeneity, variation of mechanisms of resistance to β-lactams
in a single clone and the predominance of chromosomally encoded resistance mechanisms 相似文献
7.
Passero LF Carvalho AK Bordon ML Bonfim-Melo A Toyama MH Corbett CE Laurenti MD 《Inflammation research》2012,61(3):255-263
Objective
Leishmania (Viannia) shawi was characterized only recently, and few studies concerning the immunogenic and protective properties of its antigens have been performed. The present study aimed to evaluate the protective potential of the five antigenic fractions isolated from L. (V.) shawi promastigotes in experimental cutaneous leishmaniasis. 相似文献8.
Karina?M.?Rebello Luzia?M.?C.?C?rtes Bernardo?A.?S.?Pereira Bernardo?M.?O.?Pascarelli Suzana?C?rte-Real Léa?C.?Finkelstein Rosa?T.?Pinho Claudia?M.?d’Avila-Levy Carlos?R.?Alves 《Parasitology research》2009,106(1):95-104
Leishmania (Viannia) braziliensis is the major causative agent of American tegumentary leishmaniasis, a disease that has a wide geographical distribution and
is a severe public health problem. The cysteine proteinase B (CPB) from Leishmania spp. represents an important virulence factor. In this study, we characterized and localized cysteine proteinases in L. (V.) braziliensis promastigotes. By a combination of triton X-114 extraction, concanavalin A-affinity, and ion exchange chromatographies, we
obtained an enriched fraction of hydrophobic proteins rich in mannose residues. This fraction contained two proteinases of
63 and 43 kDa, which were recognized by a CPB antiserum, and were partially sensitive to E-64 in enzymatic assays with the
peptide Glu-Phe-Leu. In confocal microscopy, the CPB homologues localized in the peripheral region of the parasite. This data
together with direct agglutination and flow cytometry assays suggest a surface localization of the CPB homologues. The incubation
of intact promastigotes with phospholipase C reduced the number of CPB-positive cells, while anti-cross-reacting determinant
and anti-CPB antisera recognized two polypeptides (63 and 43 kDa) derived from phospholipase C treatment, suggesting that
some CPB isoforms may be glycosylphosphatidylinositol-anchored. Collectively, our results suggest the presence of CPB homologues
in L. braziliensis surface and highlight the need for further studies on L. braziliensis cysteine proteinases, which require enrichment methods for enzymatic detection. 相似文献
9.
Edílson Damke Joyce K Tsuzuki Diógenes AG Cortez Izabel CP Ferreira Thâmara A Bertoni Márcia R Batista Lucélia Donati Terezinha IE Svidzinski Márcia EL Consolaro 《BMC complementary and alternative medicine》2011,11(1):35
Background
Study of in vivo antifungal activity of the hydroalcoholic extract (HE) and n-BuOH extract (BUTE) of Sapindus saponaria against azole-susceptible and -resistant human vaginal Candida spp. 相似文献10.
Hongtao Li Lili Wang Lu Ye Yan Mao Xuhua Xie Chao Xia Jia Chen Zimin Lu Jianxin Song 《Medical microbiology and immunology》2009,198(2):113-121
Quorum sensing system is a cell-to-cell communication system that plays a pivotal role in virulence expression in bacteria.
Recent advances have demonstrated that the Pseudomonas aeruginosa quorum sensing molecule, N-3-oxododecanoyl homoserine lactone (3OC12-HSL), exerts effects on mammalian cells and modulates host immune response. Mast cells (MCs) are strategically located in
the tissues that are constantly exposed to external stimulus. Therefore, it is very much possible that 3OC12-HSL may interact with MCs. Little is known, however, about specific effects of 3OC12-HSL on MCs. To address this, we investigated the influence of 3OC12-HSL on cell viability, apoptosis, intracellular calcium and cytokine release in MCs. We found that at high concentrations
(100 μM), 3OC12-HSL inhibited proliferation and induced apoptosis in P815. The 3OC12-HSL treatment significantly increased intracellular calcium release in both P815 and HMC-1. We also observed that 3OC12-HSL-induced histamine release and degranulation in HMC-1 cells. Furthermore, 3OC12-HSL-induced IL-6 production at lower concentrations (6.25–12.5 μM) but steadily reduced IL-6 production at high concentration
(50–100 μM). These data demonstrate that P. aeruginosa 3OC12-HSL affects MCs function. 相似文献
11.
A. Doléans-Jordheim B. Cournoyer E. Bergeron J. Croizé H. Salord J. André M.-A. Mazoyer F. N. R. Renaud J. Freney 《European journal of clinical microbiology & infectious diseases》2009,28(9):1105-1111
The purpose of this study was to evaluate the possibility of using a semi-automated repetitive DNA sequences-based polymerase chain reaction (rep-PCR) for typing Pseudomonas aeruginosa isolates. rep-PCR profiles obtained by the DiversiLab® system of 84 P. aeruginosa isolates from distinct epidemiological situations were obtained. rep-PCR groupings were in good agreement with the origin of these isolates. Linked rep-PCR profiles were observed for isolates recovered from a same family of cystic fibrosis (CF) patients, for the etiological agents of clustered cases of nosocomial infections, and for some isolates recovered from a same hospital room. rep-PCR and pulsed-field gel electrophoresis SpeI restricted genomic DNA (PFGE-SpeI) profiles were compared. In a few instances, rep-PCR revealed genetic divergences among isolates of a same group of PFGE-SpeI profiles. These divergences could reflect genetic drifts among closely related isolates, as illustrated by those observed between clinical and environmental isolates of a same group of PFGE-SpeI profiles. The interpretation of such differences will require further studies, but the rep-PCR analysis of P. aeruginosa diversity appeared to be an appropriate method to investigate infra-specific genetic relatedness. 相似文献
12.
L. Dales W. Ferris K. Vandemheen S. D. Aaron 《European journal of clinical microbiology & infectious diseases》2009,28(10):1275-1279
We identified double and triple antibiotic combinations effective against biofilm-grown Burkholderia cepacia and Pseudomonas aeruginosa sampled from cystic fibrosis (CF) patients undergoing acute pulmonary exacerbations. Sputum bacteria from 110 CF patients
were grown as biofilms. Combination antibiotic susceptibility testing was used to test 94 double and triple antibiotic combinations.
Biofilm-grown bacterial isolates were less susceptible to antibiotic combinations compared to the same bacterial isolates
grown planktonically (P < 0.001). Fifty-nine percent of biofilm-grown B. cepacia isolates and 29% of P. aeruginosa isolates were resistant to all double antibiotic combinations tested. Triple antibiotic combinations were more effective
than double antibiotic combinations against biofilms (P < 0.0001). For P. aeruginosa biofilms, the addition of azithromycin or rifampin to otherwise effective antibiotic combinations was frequently associated
with antagonism. Bacterial biofilms of CF organisms are highly resistant to antibiotics. This study identified potentially
effective antibiotic combinations to guide the empirical treatment of CF pulmonary exacerbations. 相似文献
13.
Bardia A Tiwari SK Gunisetty S Anjum F Nallari P Habeeb MA Khan AA 《Inflammation research》2012,61(4):359-365
Objective
The present study was designed to investigate the role of X-ray cross-complementing group 1 (XRCC1) and apurinic/apyrimidinic endonuclease 1 (APE1) polymorphisms in apoptosis and the risk of ulcerative colitis (UC). 相似文献14.
María del Rosario Robles James E. Loudon John M. Kinsella Mandala Hunter-Ishikawa David S. Miller Michelle L. Sauther Frank P. Cuozzo 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2010,55(3):270-275
Lemuricola (Madoxyuris) bauchoti Chabaud, Brygoo et Petter, 1965 is redescribed from material collected from the ring-tailed lemur, Lemur catta, from the Beza Mahafaly Special Reserve in Madagascar using the scanning electron microscope. This is a new host record and
the first oxyurid reported from the ring-tailed lemur. Previously, records of each species of the subgenus Madoxyuris have been restricted to a single host species, but the close relationship between these nematodes and their Strepsirrhini
hosts will only be proven when additional records fill in the gaps in their distribution. 相似文献
15.
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17.
In the present study activity of silver nanoparticles (AgNPs) synthesized using Plumeria rubra plant latex against second and fourth larval instar of Aedes aegypti and Anopheles stephensi was determined. Range of concentrations of synthesized AgNps (10, 5, 2.5, 1.25, 0.625, 0.3125 ppm) and aqueous crude latex
(1,000, 500, 250, 125, 62.50, 31.25 ppm) were tested against larvae of A. aegypti and A. Stephensi. The synthesized AgNps from P. rubra latex were highly toxic than crude latex extract in both mosquito species. The LC50 values for second and fourth larval instars after 24 h of crude latex exposure were 1.49, 1.82 ppm against A. aegypti and 1.10, 1.74 ppm against A. stephensi respectively. These figures were 181.67, 287.49 ppm against A. aegypti and 143.69, 170.58 ppm against A. stephensi respectively for crude latex extract. The mortality rates were positively correlated with the concentration of AgNPs. The
characterization studies of synthesized AgNPs by UV–Vis spectrophotometry, transmission electron microscopy (TEM), Particle
size analysis (PSA) and zeta potential confirmed the spherical shape and size (32–200 nm) of silver nanoparticles alongwith
stability. Toxicity studies carried out against non-target fish species Poecilia reticulata, the most common organism in the habitats of A. aegypti and A. stephensi showed no toxicity at LC50 and LC90 doses of the AgNPs. This is the first report on mosquito larvicidal activity of latex synthesized nanoparticles. 相似文献
18.
Mosquitoes are important vectors of diseases to humans and domestic animals. Chemical control of vectors remains a main resource
for the prevention and control of vector-borne diseases. Due to the development of insecticide resistance and risks to human
health and the environment of synthetic compounds, the search for alternative pesticides is encouraged. This work assessed
the insecticidal activity of essential oils (EOs) from Lippia turbinata and L. polystachya from Argentina on Culex quinquefasciatus mosquitoes. EOs were extracted by hydro-distillation and analyzed with gas–liquid chromatography and mass spectrometry. The
insecticidal activity against mosquito larvae, pupae, and adults were evaluated according to World Health Organization protocols.
Concentrations ranking from 10 to 160 ppm were assessed at 1, 2, 3, and 24 h posttreatment. The composition of the EO of L. polystachya and L. turbinata were qualitatively similar, with α-thujone and carvone as main constituent; differences were mostly due to the proportion
of each component. β-caryophyllene was also an important constituent of the EO of L. turbinata. Both EO were larvicidal at concentrations of 80 ppm or higher, but only L. turbinata was adulticidal. No pupal mortality was detected. The potential of these EOs for vector control is discussed. 相似文献
19.
Fidelis Cho-Ngwa Melanie Abongwa Moses N Ngemenya Kennedy D Nyongbela 《BMC complementary and alternative medicine》2010,10(1):62
Background
The current treatment of onchocerciasis relies on the use of ivermectin which is only microfilaricidal and for which resistant parasite strains of veterinary importance are increasingly being detected. In the search for novel filaricides and alternative medicines, we investigated the selective activity of crude extracts of Margaritaria discoidea and Homalium africanum on Onchocerca ochengi, a model parasite for O. volvulus. These plants are used to treat the disease in North West Cameroon. 相似文献20.
Sundaram Ravikumar Ganesan Ramanathan Samuel Jacob Inbaneson Andy Ramu 《Parasitology research》2011,108(1):107-113
The ocean covers more than 70% of earth surface and hosts most 300,000 described species of plants and animals to use, which
have been virtually unexploited for the development of medicines. Marine plants are the good source of biologically active
entities which exhibit therapeutic properties, when applied single or in combination of different plant extracts (polyherbal).
Polyherbal preparations are always a complex mixture of different forms and thus different compounds, which might act as agonistic,
synergistic, complementary, antagonistic or toxic way. The present study was initially carried out to test the antiplasmodial
activity of 13 mangrove plants and eight seaweeds species distributed along the coast of south India. Of these, mangrove species
Aegiceras corniculatum and the seaweed species Chaetomorpha antennina have shown maximum antiplasmodial activity. Hence, the present study was mooted out to increase the percentage of antiplasmodial
activity when applied as polyherbal preparations. The effect of marine polyherbal preparations from the methanolic extracts
of two marine plants A. corniculatum and C. antennina for their antiplasmodial activity was tested. It shows that the polyherbal extract showed 63.50 ± 0.408% suppression of parasitaemia
against Plasmodium falciparum at 1.5 mg ml−1 concentration. In vivo test was carried out with rat animal model to find out the effectiveness of the polyherbal extracts
in the live system, which reveals that polyherbal extracts have exhibited remarkable antiplasmodial activity (50.57 ± 0.465%)
against Plasmodium berghei at 120 mg kg−1 bw. This study shows that combinations of mangrove plants and seaweeds extracts had a source of lead compounds for the development
of new drugs for the treatment of malaria. 相似文献