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1.
Ralciane de Paula MENEZES Joseane Cristina FERREIRA Walkiria Machado de Sá Tomaz de Aquino MOREIRA Lucivania Duarte Silva MALVINO Lucio Borges de ARAUJO Denise Von Dolinger de Brito R?DER Mario Paulo Amante PENATTI Regina Celia CANDIDO Reginaldo dos Santos PEDROSO 《Revista do Instituto de Medicina Tropical de S?o Paulo》2015,57(3):185-191
Infections by Candida species are a high-impact problem in public
health due to their wide incidence in hospitalized patients. The goal of this study
was to evaluate frequency, susceptibility to antifungals, and genetic polymorphism of
Candida species isolated from clinical specimens of hospitalized
patients. The Candida isolates included in this study were obtained
from blood cultures, abdominal fluids, and central venous catheters (CVC) of
hospitalized patients at the Clinical Hospital of the Federal University of
Uberlândia during the period of July 2010 - June 2011. Susceptibility tests were
conducted by the broth microdilution method. The RAPD-PCR tests used employed
initiator oligonucleotides OPA09, OPB11, and OPE06. Of the 63
Candida isolates, 18 (28.5%) were C. albicans,
20 (31.7%) were C. parapsilosis complex species, 14 (22.2%)
C. tropicalis, four (6.4%) C. glabrata, four
(6.4%) C. krusei, two (3.3%) C. kefyr, and one
(1.6%) C. lusitaniae. In vitro resistance to
amphotericin B was observed in 12.7% of isolates. In vitroresistance
to azoles was not detected, except for C. krusei. The two primers,
OPA09 and OPB11, were able to distinguish different species. Isolates of C.
albicans and C. parapsilosis complex species presented
six and five clusters, respectively, with the OPA09 marker by RAPD-PCR, showing the
genetic variability of the isolates of those species. It was concluded that members
of the C. parapsilosis complex were the most frequent species found,
and most isolates were susceptible to the antifungals amphotericin B, flucozanole,
and itraconazole. High genetic polymorphisms were observed for isolates of C.
albicans and C. parapsilosis complex species, mainly
with the OPA09 marker. 相似文献
2.
Vanessa Kummer Perinazzo Oliveira Luciana da Silva Ruiz Nélio Alessandro Jesus Oliveira Débora Moreira Rosane Christine Hahn Analy Salles de Azevedo Melo Angela Satie Nishikaku Claudete Rodrigues Paula 《Revista do Instituto de Medicina Tropical de S?o Paulo》2014,56(4):301-305
Candidemia remains a major cause of morbidity and mortality in the health
care environment. The epidemiology of Candida infection is changing,
mainly in relation to the number of episodes caused by species C.
non-albicans. The overall objective of this study was to evaluate
the frequency of yeasts of the genus Candida, in a four-year period,
isolated from blood of pediatric patients hospitalized in a public hospital of the
city of São Paulo, Brazil. In this period, yeasts from blood of 104 patients were
isolated and, the identified species of Candida by phenotypic and
genotypic methods were: C. albicans (39/104), C.
tropicalis (25/104), C. parapsilosis (23/104),
Pichia anomala (6/104), C. guilliermondii
(5/104), C. krusei (3/104), C. glabrata (2/104) and
C. pararugosa (1/104). During the period of the study, a higher
frequency of isolates of C. non-albicans (63.55%)
(p = 0.0286) was verified. In this study we verified the increase
of the non-albicans species throughout the years (mainly in 2009 and
2010). Thus, considering the peculiarities presented by Candida
species, a correct identification of species is recommended to lead to a faster
diagnosis and an efficient treatment. 相似文献
3.
Fernanda Cristina Possamai Rossatto Letícia Auler Proen?a Ana Paula Becker Alessandro Conrado de Oliveira Silveira Juliana Caier?o Pedro Alves D'azevedo 《Revista do Instituto de Medicina Tropical de S?o Paulo》2014,56(6):469-472
INTRODUCTION: Methicillin-Resistant
Staphylococcus aureus (MRSA) presenting reduced
susceptibility to vancomycin has been associated to therapeutic failure. Some
methods used by clinical laboratories may not be sufficiently accurate to detect
this phenotype, compromising results and the outcome of the patient.
OBJECTIVES: To evaluate the performance of methods in the
detection of vancomycin MIC values among clinical isolates of MRSA.
MATERIAL AND METHODS: The Vancomycin Minimal Inhibitory
Concentration was determined for 75 MRSA isolates from inpatients of Mãe de
Deus Hospital, Porto Alegre, Brazil. The broth microdilution (BM) was
used as the gold-standard technique, as well as the following methods:
E-test® strips (BioMérieux),
M.I.C.E® strips (Oxoid), PROBAC®
commercial panel and the automated system MicroScan®
(Siemens). Besides, the agar screening test was carried out with 3
µg/mL of vancomycin.
RESULTS: All isolates presented MIC ≤ 2
µg/mL for BM. E-test® had higher concordance
(40%) in terms of global agreement with the gold standard, and
there was not statistical difference among E-test® and broth
microdilution results. PROBAC® panels presented MICs, in
general, lower than the gold-standard panels (58.66% major
errors), while M.I.C.E.® MICs were higher (67.99%
minor errors).
CONCLUSIONS: For the population of MRSA in question,
E-test® presented the best performance, although with a
heterogeneous accuracy, depending on MIC values. 相似文献
4.
Patrícia de Souza Bonfim-Mendon?a Adriana Fiorini Cristiane Suemi Shinobu-Mesquita Lilian Cristiane Baeza Maria Aparecida Fernandez Terezinha Inez Estivalet Svidzinski 《Revista do Instituto de Medicina Tropical de S?o Paulo》2013,55(6):385-391
SUMMARY
Introduction: The majority of nosocomial fungal infections are caused by Candida spp. where C. albicans is the species most commonly identified. Molecular methods are important tools for assessing the origin of the yeasts isolated in hospitals. Methods: This is a study on the genetic profifiles of 39 nosocomial clinical isolates of C. albicans using two typing methods: random amplifified polymorphic DNA (RAPD) and microsatellite, two different primers for each technique were used. Results: RAPD provided 10 and 11 different profiles with values for SAB of 0.84 ± 0.126 and 0.88 ± 0.08 for primers M2 and P4, respectively. Microsatellite using two markers, CDC3 and HIS3, allowed the observation of six and seven different alleles, respectively, with combined discriminatory power of 0.91. Conclusions: Although genetic variability is clear, it was possible to identify high similarity, suggesting a common origin for at least a part of isolates. It is important to emphasize that common origin was proven from yeasts isolated from colonization (urine, catheter or endotracheal secretions) and blood culture from the same patient, indicating that the candidemia must have started from a site of colonization. The combination of RAPD and microsatellite provides a quick and efficient analysis for investigation of similarity among nosocomial isolates of C. albicans. 相似文献5.
P. Sugandhi D. Arvind Prasanth 《International journal of diabetes in developing countries.》2017,37(1):50-57
Diabetic foot infections are a serious threat which cause a long term of hospitalization of diabetes patients and lead to amputations. Hence, prompt diagnosis is an important criterion in the treatment of these infections. This study was carried out to determine the prevalence of yeast in diabetic foot infections. The pus samples were collected from patients presenting with diabetic foot ulcer and processed for microbiological investigation. The patients investigated comprised of 82 males and 78 females. Most of the patients were grade I ulcers followed by grade II ulcers. Out of 160 samples, 138 samples were culture positive, in which yeast isolate Candida glabrata was the predominant isolate followed by Candida albicans, Candida dubliniensis, Candida krusei and Candida tropicalis. C. albicans and C. dubliniensis were differentiated by using tobacco agar due to the presence of hyphal fringes. The methylene blue sabouraud dextrose agar and corn meal agar were also used to differentiate C. albicans from non albicans. The antifungal susceptibility pattern showed 29 % of C. albicans was sensitive to Amphotericin B and Clotrimazole, while 75 % of C. glabrata was sensitive to Amphotericin B, Ketoconazole and Itraconazole. C. dublinensis and C. albicans showed the highest percentage of resistant to Ketoconazole, Fluconazole, Nystatin and Itraconazole. Thus, the results indicating that effective alternate drug of choice are required and the proper selection of antifungal agents will play an important role for the treatment of fungal foot infections. This study will also add substantial knowledge of yeast as one of the pathogenic organisms in diabetic foot infections. 相似文献
6.
Denise Pires Machado Luciano Z Goldani Rodrigo Minuto Paiva Valério Rodrigues Aquino Fernanda de-Paris Thiago Lisboa Bruno Jung Rodrigo Pires dos Santos 《The Canadian Journal of Infectious Diseases & Medical Microbiology》2013,24(3):e75-e79
BACKGROUND:
Vancomycin is the treatment of choice for methicillin-resistant Staphylococcus aureus (MRSA) infections; however, treatment failure is not uncommon, even when the minimum inhibitory concentration (MIC) of the MRSA strain is within the susceptible range for vancomycin.OBJECTIVE:
To describe the relationship between molecular markers such as the mecA and agrII genes, serum vancomycin levels and vancomycin MICs, and the 30-day mortality rate of patients with nosocomial MRSA pneumonia in an intensive care unit (ICU).METHODS:
The present study was a prospective cohort study including all patients with MRSA hospital-acquired pneumonia or ventilator-associated pneumonia who were admitted to the ICU of a tertiary care hospital between June 2009 and December 2011. The MIC for vancomycin was determined using the E-test and broth microdilution methods. Variables analyzed included age, sex, comorbid conditions, serum vancomycin trough concentration, the Acute Physiology and Chronic Health Evaluation II (APACHE) score and the presence of the agrII gene. The primary outcome was mortality at 30 days.RESULTS:
Thirty-six (42.4%) patients died within 30 days of the index MRSA culture. A multiple regression analysis that included the variables of MIC (determined using the E-test or broth microdilution methods), APACHE II score, serum vancomycin level and the presence of agrII revealed that only the APACHE II score was related to the 30-day mortality rate (P=0.03). Seven patients (9.0%) with isolates exhibiting an MIC ≥1.5 μg/mL according to the E-test method died, and nine patients (11.6%) survived (P=0.76). Of the patients for whom MICs were determined using the broth microdilution method, 11 (14.1%) patients with MICs of 1.0 μg/mL died, and 16 (20.5%) survived (P=0.92). The median APACHE II score of survivors was 22.5, and the median score of nonsurvivors was 25.0 (P=0.03). The presence of the agrII gene was not related to the 30-day mortality rate.CONCLUSIONS:
Patients with severe hospital-acquired pneumonia presented with MRSA isolates with low to intermediate vancomycin MICs in the ICU setting. At the Hospital de Clínicas de Porto Alegre (Porto Alegre, Brazil), the 30-day mortality rate was high, and was similar among patients with severe hospital-acquired pneumonia infected with MRSA isolates that exhibited MICs of ≤1.5 μg/mL determined using the E-test method and ≤1.0 μg/mL determined using the broth microdilution method in those who achieved optimal serum vancomycin levels. The APACHE II scores which provides an overall estimate of ICU mortality were independently associated with mortality in the present study, regardless of the MICs determined. Molecular markers, such as the agrII gene, were not associated with higher mortality in the present study. 相似文献7.
Sreedevi Padmanabhan Jitendra Thakur Rahul Siddharthan Kaustuv Sanyal 《Proceedings of the National Academy of Sciences of the United States of America》2008,105(50):19797-19802
The Cse4p-containing centromere regions of Candida albicans have unique and different DNA sequences on each of the eight chromosomes. In a closely related yeast, C. dubliniensis, we have identified the centromeric histone, CdCse4p, and shown that it is localized at the kinetochore. We have identified putative centromeric regions, orthologous to the C. albicans centromeres, in each of the eight C. dubliniensis chromosomes by bioinformatic analysis. Chromatin immunoprecipitation followed by PCR using a specific set of primers confirmed that these regions bind CdCse4p in vivo. As in C. albicans, the CdCse4p-associated core centromeric regions are 3–5 kb in length and show no sequence similarity to one another. Comparative sequence analysis suggests that the Cse4p-rich centromere DNA sequences in these two species have diverged faster than other orthologous intergenic regions and even faster than our best estimated “neutral” mutation rate. However, the location of the centromere and the relative position of Cse4p-rich centromeric chromatin in the orthologous regions with respect to adjacent ORFs are conserved in both species, suggesting that centromere identity is not solely determined by DNA sequence. Unlike known point and regional centromeres of other organisms, centromeres in C. albicans and C. dubliniensis have no common centromere-specific sequence motifs or repeats except some of the chromosome-specific pericentric repeats that are found to be similar in these two species. We propose that centromeres of these two Candida species are of an intermediate type between point and regional centromeres. 相似文献
8.
Edna Cleide Mendes Muricy Romilda Aparecida Lemes Sidney Bombarda Lucilaine Ferrazoli Erica Chimara 《Revista do Instituto de Medicina Tropical de S?o Paulo》2014,56(5):397-401
New methodologies were developed for the identification of
Nocardia but the initial diagnosis still requires a fast
and accurate method, mainly due to the similarity to
Mycobacterium, both clinical and bacteriologically. Growth
on Löwenstein-Jensen (LJ) medium, presence of acid-fast bacilli
through Ziehl-Neelsen staining, and colony morphology can be confusing aspects
between Nocardia and Mycobacterium. This study
describes the occurrence of Nocardia spp. in a
mycobacterial-reference laboratory, observing the main difficulties in
differentiating Nocardia spp. from
Mycobacterium spp., and correlating isolates with
nocardiosis cases. Laboratory records for the period between 2008 and 2012 were
analyzed, and the isolates identified as Nocardia sp. or as
non-acid-fast filamentous bacilli were selected. Epidemiological and
bacteriological data were analyzed as well. Thirty-three isolates identified as
Nocardia sp. and 22 as non-acid-fast bacilli were selected
for this study, and represented 0.12% of isolates during the study period.
The presumptive identification was based on macroscopic and microscopic
morphology, resistance to lysozyme and restriction profiles using the
PRA-hsp65 method. Nocardia spp. can grow
on media for mycobacteria isolation (LJ and BBL MGIT™) and
microscopy and colony morphology are very similar to some mycobacteria species.
Seventeen patients (54.8%) were reported and treated for
tuberculosis, but presented signs and symptoms of nocardiosis. It was concluded
that the occurrence of Nocardia sp. during the study period was
0.12%. Isolates with characteristics of filamentous bacilli, forming aerial
hyphae, with colonies that may be pigmented, rough and without the BstEII
digestion pattern in PRA-hsp65 method are suggestive of
Nocardia spp. For a mycobacterial routine laboratory, a
flow for the presumptive identification of Nocardia is
essential, allowing the use of more accurate techniques for the correct
identification, proper treatment and better quality of life for patients. 相似文献
9.
Wanda Cornistein Andrea Mora Nora Orellana Federico Javier Capparelli Marcelo del Castillo 《Enfermedades infecciosas y microbiología clínica》2013
Introduction
Nosocomial fungal infections have increased significantly in the last decade. Candida detection in clinical specimens can mean either colonization or an infection which can be local (muguet) or invasive. Knowledge of the species helps in choosing the best treatment. The aims of this study were to determine the frequency and distribution of Candida species detected in clinical samples, to analyze the clinical characteristics of the involved population and to determine the risk factors for Candida non-albicans species.Methods
Retrospective, observational. Period: 2006-2010. Inclusion criteria: all isolates of Candida in clinical specimens from patients hospitalized —at least 48 hours in a neurological center. We analyzed epidemiological characteristics, co morbidities, risk factors, factors associated with Candida non-albicans detection, antifungal treatment, development of adverse events and mortality.Results
Candida spp. was isolated from 321 clinical specimens: 139 (43.3%) were C. albicans and 182 (56.7%) Candida non-albicans. The distribution of the sample was: urine 122 (Candida non-albicans 67.2%), airway 81, oropharynx 45 (C. albicans) and candidemia 40 (Candida non-albicans 75%). The most frequent co-morbidity was solid tumor (35.5%). The main risk factors were antibiotic therapy (85.5%), steroid therapy (61.7%) and in ICU at diagnosis (61.6%). The analysis of risk factors and the isolation of Candida non-albicans shows that chemotherapy, previous surgery, treatment with aminopenicillins, carbapenems and glycopeptides were statistically significant (P < .05). There is a trend in neutropenic patients (P = .055) and in ICU at diagnosis (P = .076). Overall survival was 71%.Conclusions
Candida species distribution varies with the type of sample analyzed. Non-albicans species make up the majority of the isolates. The identification of the species involved per sample helps to optimize treatment. The high frequency of isolation of Candida in patients on steroids and antibiotics and admitted to ICU, is worth pointing out. Patients with previous surgery, treated with the aforementioned antibiotics or chemotherapy, could receive non-azole antifungals in the initial empirical treatment strategy. 相似文献10.
Helicobacter pylori acquistion of metronidazole resistance by natural transformation in vitro 总被引:1,自引:0,他引:1
AIM: To study whether Helicobacter pylori is naturally transformable.METHODS: Transformation was performed in BHI broth supplemented with horse serum and yeast extract. Genomic DNA extracted from a metronidazole resistant H.pylori strain was added to H. pylori broth culture. The mixture was incubated at microaerophilic atmosphere. The DNA-treated cells were plated on blood agar containing 8 mg/L metronidazole to select for transformants. Sterile distilled water was used as a negative DNA control. The DNA profiles of transformants were compared with that of their parent strains by randomly amplified polymorphic DNA (RAPD) fingerprinting.RESULTS: Transformation of H. pylori with DNA from a metronidazole resistant strain as a marker was demonstrated. Out of the 12 strains of H. pylori tested, 9 (75%) strains were found to be transformable. The transformation frequencies ranged from 3.4 × 10-6 to 2.4 × 10-4. By RAPD, DNA fingerprints of the transformants and their parent strains showed no change in DNA profiles though transformants were all resistant to metronidazole as compared with their metronidazole-sensitive parent strains.CONCLUSION: Helicobacter pylori is naturally transformable which might be one of the ways that H. pylori develops resistance to metronidazole. 相似文献
11.
Sheena D. Singh-Babak Tomas Babak Hunter B. Fraser Alexander D. Johnson 《Proceedings of the National Academy of Sciences of the United States of America》2021,118(12)
Candida albicans is the most common cause of systemic fungal infections in humans and is considerably more virulent than its closest known relative, Candida dubliniensis. To investigate this difference, we constructed interspecies hybrids and quantified mRNA levels produced from each genome in the hybrid. This approach systematically identified expression differences in orthologous genes arising from cis-regulatory sequence changes that accumulated since the two species last shared a common ancestor, some 10 million y ago. We documented many orthologous gene-expression differences between the two species, and we pursued one striking observation: All 15 genes coding for the enzymes of glycolysis showed higher expression from the C. albicans genome than the C. dubliniensis genome in the interspecies hybrid. This pattern requires evolutionary changes to have occurred at each gene; the fact that they all act in the same direction strongly indicates lineage-specific natural selection as the underlying cause. To test whether these expression differences contribute to virulence, we created a C. dubliniensis strain in which all 15 glycolysis genes were produced at modestly elevated levels and found that this strain had significantly increased virulence in the standard mouse model of systemic infection. These results indicate that small expression differences across a deeply conserved set of metabolism enzymes can play a significant role in the evolution of virulence in fungal pathogens.Microbial pathogens of humans typically have at least one close, nonpathogenic relative, and comparisons between the two provide a powerful entry point to identify and study disease-causing determinants. This approach has revealed numerous bacterial pathogenicity islands, clusters of genes required for a given strain or species to cause disease in humans. Because these gene clusters can be horizontally transferred, they can often be initially identified by comparing genome sequences of pathogenic and nonpathogenic strains. The situation with fungal pathogens is substantially different. Like their human hosts, these microbes are eukaryotes, and genes that work together are typically dispersed across different chromosomes rather than clustered; not surprisingly, horizontal transfer of groups of cofunctioning genes from one fungal species to another is rare. Thus, identifying and understanding how groups of genes work together to contribute to virulence remains a challenge in fungi.In this report, we consider two fungal pathogens that are closely related but differ in their virulence. Candida albicans is an opportunistic pathogen; it is a component of the normal human microbiota but is also the leading cause of systemic fungal infections in humans, which can have mortality rates as high as 40%. It is highly virulent when injected into the tail vein of mice, a standardized laboratory procedure that initiates a systemic blood stream infection. Candida dubliniensis is the closest known relative of C. albicans; it was first identified from the oral cavity of an HIV-infected patient and is typically found only as secondary infections. Although it is found throughout the world, C. dubliniensis is much less prevalent than C. albicans in the clinic; it is also less virulent in the mouse model of systemic infection, based on time-to-illness measurements (1–5).C. albicans and C. dubliniensis last shared a common ancestor nominally 10 million y ago, and their genomes are very similar in terms of gene content and synteny. A small number of individual genes are “missing” in one species compared to the other but there are also wide-scale differences in the expression of those genes conserved in both species (6–10). It has been proposed that both types of differences—in gene content and in regulation—contribute to the difference in pathogenicity, although neither idea has been directly demonstrated.In this report, we used an approach known as “allele-specific expression” to highlight patterns of gene-expression differences between C. albicans and C. dubliniensis and to identify those that bear the hallmarks of selection (11–15). Specifically, we created an interspecies hybrid between C. albicans (strain SC5314) and C. dubliniensis (strain CD36) by forcing them to mate with each other (16) (Fig. 1A). Both strains were originally isolated from human patients, and both have been studied extensively in the laboratory. In the hybrid, both parental genomes reside in the same cell, so any bias in mRNA levels must be due to cis-acting sequences specific to that genome. We show that ∼40% of orthologous gene pairs show statistically significant differences in their mRNA levels in the interspecies hybrid, although many of these differences are small in magnitude. We searched for pathways that showed a systematic up-regulation from one genome compared to the other, and were led to the genes for glycolysis, all 15 of which exhibited increased expression from the C. albicans genome compared with the C. dubliniensis genome. This pattern requires cis-acting changes to have accumulated at each of the 15 genes, all resulting in higher mRNA expression from the C. albicans alleles in the hybrid. The likelihood of this pattern emerging by chance is extremely low, and the observation strongly implies that this nonrandom pattern is the result of natural selection.Open in a separate windowFig. 1.RNA-seq of an interspecies hybrid systematically identifies gene-expression differences between C. albicans and C. dubliniensis that arose through cis-acting changes that accumulated since the two species shared a common ancestor. (A) C. albicans and C. dubliniensis (both diploid) were mated to a create tetraploid interspecies hybrid strain, using mating and auxotrophic marker complementation. We performed RNA-seq in the hybrid strain in the conditions listed, as well as the parent diploid strains in bovine plasma at 37 °C. We aligned RNA-seq reads to a concatenated C. albicans–C. dubliniensis genome and excluded reads mapping to both genomes or to multiple locations within a single genome (<5% of total reads). Systematic gene-expression differences of orthologous genes between the two species were assessed. Since both genomes were in the same trans-acting environment (that is, the hybrid strain), all measurable gene expression changes must be due to cis-acting changes. (B) Correlation between two replicate RNA-seq experiments of the interspecies hybrid grown in YPD at 30 °C. Each point represents the log2 ratio of reads from the C. albicans genome versus reads from the C. dubliniensis genome in the interspecies hybrid, for each orthologous gene pair, with experimental replicates plotted on each axis. Points in the upper right quadrant represent genes with higher expression from the C. albicans genome than C. dubliniensis genome in the interspecies hybrid, and points in the lower left quadrant represent genes with higher expression from the C. dubliniensis genome than the C. albicans genome in that same hybrid, with Spearman correlation values shown in the lower right. We observed very high correlation between replicate experiments for all conditions tested (SI Appendix, Figs. S1 and S2).To test whether increased glycolysis gene expression could account for at least some of the virulence difference between C. albicans and C. dubliniensis, we created a C. dubliniensis strain in which the glycolysis genes were modestly overexpressed and found that this engineered strain showed enhanced virulence (compared with the parental strain) in the standard mouse model for disseminated candidiasis. This result indicates the importance of metabolic fitness in the establishment of fungal infections. More broadly, our results suggest that subtle changes in the expression of genes that are deeply conserved in all branches of life can play important roles in the evolution of specific pathogens. 相似文献
12.
Peleg AY Tampakakis E Fuchs BB Eliopoulos GM Moellering RC Mylonakis E 《Proceedings of the National Academy of Sciences of the United States of America》2008,105(38):14585-14590
Prokaryote–eukaryote interactions are ubiquitous and have important medical and environmental significance. Despite this, a paucity of data exists on the mechanisms and pathogenic consequences of bacterial–fungal encounters within a living host. We used the nematode Caenorhabditis elegans as a substitute host to study the interactions between two ecologically related and clinically troublesome pathogens, the prokaryote, Acinetobacter baumannii, and the eukaryote, Candida albicans. After co-infecting C. elegans with these organisms, we observed that A. baumannii inhibits filamentation, a key virulence determinant of C. albicans. This antagonistic, cross-kingdom interaction led to attenuated virulence of C. albicans, as determined by improved nematode survival when infected with both pathogens. In vitro coinfection assays in planktonic and biofilm environments supported the inhibitory effects of A. baumannii toward C. albicans, further showing a predilection of A. baumannii for C. albicans filaments. Interestingly, we demonstrate a likely evolutionary defense by C. albicans against A. baumannii, whereby C. albicans inhibits A. baumannii growth once a quorum develops. This counteroffensive is at least partly mediated by the C. albicans quorum-sensing molecule farnesol. We used the C. elegans–A. baumannii–C. albicans coinfection model to screen an A. baumannii mutant library, leading to the identification of several mutants attenuated in their inhibitory activity toward C. albicans. These findings present an extension to the current paradigm of studying monomicrobial pathogenesis in C. elegans and by use of genetic manipulation, provides a whole-animal model system to investigate the complex dynamics of a polymicrobial infection. 相似文献
13.
Gokben Ozbey Yasar Dogan Kaan Demiroren 《World journal of gastroenterology : WJG》2013,19(39):6585-6589
AIM:To identify the virulence genotypes of Helicobacter pylori(H.pylori)if present in children in Eastern Turkey and if those genotypes are mostly associated with severe clinical presentations.METHODS:A total of 49 H.pylori positive Turkish children(42 with antral nodularity and 7 with peptic ulcer)who underwent upper gastrointestinal endoscopy with abdominal symptoms during the period from March 2011 to September 2012 were enrolled in this study.Antral nodularity was diagnosed endoscopically by two of the authors.We determined for the presence of cagA,vacA,cagE,iceA and babA2 genotypes of H.pylori isolates in DNA obtained directly from frozen gastric biopsy samples by polymerase chain reaction test using specific primers.RESULTS:Of the 49 H.pylori isolates studied,61.2%,91.8%,22.4%,28.6%,57.1%and 40.8%were positive for the cagA,vacA s1,cagE,iceA1,iceA2 and babA2 genes,respectively.We showed that the most common vacA subtype was s1a(79.6%).However,the s2 gene was found less frequently with an isolation rate of 8.2%of the H.pylori isolates.The genotypes iceA2 and vacA s1m2 were the most frequently found types in children with antral nodularity.In addition,the genotypes iceA1,babA2 and vacA s1m1 were found in similar ratios in all the H.pylori isolates obtained from children with peptic ulcer.The genotypes vacA s2m1and s1c were not observed in any of isolates studied.CONCLUSION:This study showed that vacA s1m2,cagA and iceA2 were the most common genotypes,and no association between antral nodularity and genotypes was observed. 相似文献
14.
Leila Shokrzadeh Fereshteh Jafari Hossein Dabiri Kaveh Baghaei Homayoun Zojaji Amir H. Alizadeh Mohammad Mehdi Aslani Mohammad R. Zali 《Saudi Journal Of Gastroenterology》2011,17(4):261-264
Background/Aim:
Helicobacter pylori is an important pathogen for gastroduodenal diseases. Infection with H. pylori can be limited by regimens of multiple antimicrobial agents. However, antibiotic resistance is a leading cause of treatment failure. The aim of this study has been to determine the resistance patterns of H. pylori strains isolated from gastric biopsies of patients with dyspepsia by agar dilution method, in Tehran, IranPatients and Methods:
H. pylori isolates from patients with gastrointestinal diseases were evaluated for susceptibility testing by agar dilution method. Susceptibility testing was performed to commonly used antibiotics including clarithromycin, tetracycline, amoxicillin, metronidazole and ciprofloxacin.Results:
Among 92 patients with dyspepsia, H. pylori strains were isolated from 42 patients. Seventeen (40.5%) of the isolates were resistant to metronidazole (MICs ≥ 8 μg/l), whereas one isolate (2.4%) was resistant to amoxicillin (MICs ≤ 0. 5 μg/ml) and ciprofloxacin (MICs ≤ 1μg/ml). The resistance rates to other antibiotics in H. pylori isolates are recorded as follows: clarithromycin 6 (14.3 %), tetracycline 2 (4.8%). In 5 of 42 resistant cases, combined resistance was found.Conclusions:
These data suggest that metronidazole should be used among Iranian patients in first-line therapy with caution, and ciprofloxacin in association with amoxicillin and a proton pump inhibitor is more recommended. 相似文献15.
Harish C. Gugnani Soni Sharma Kharl Wright 《Revista do Instituto de Medicina Tropical de S?o Paulo》2014,56(3):231-234
This report represents the first study of keratinophilic fungi present in
soils of Jamaica. Out of the 40 soil samples examined from different habitats, 30
(75%) were positive for the presence of keratinophilic fungi, yielding 36 isolates of
keratinophilic fungi. Microsporum gypseum complex (represented by 16
isolates of M. gypseum, and four of M. fulvum) was
most frequent, being present in 50% of the samples. A very high occurrence of this
dermatophyte in Jamaican soil is of public health significance. The remaining
isolates of keratinophilic fungi were represented by Chrysosporium
spp (mainly C. indicum and C. tropicum) and
Sepedonium sp. 相似文献
16.
Nnadi Nnaemeka Emmanuel Orazio Romeo Ayanbimpe Grace Mebi Ojogba Okolo Mark Fabio Scordino Enweani Ifeoma Bessy Giuseppe Criseo 《亚太热带病杂志(英文版)》2012,2(1):48-50
ObjectiveTo investigate the fluconazole susceptibility of the genotypes of Candida albicans (C. albicans) strains isolated from patients with vulvovaginal candidiasis (VVC) in Jos, Plateau State, Nigeria.MethodsA total of one hundred and seventy seven (177) Candida isolates were examined. The strains were obtained from 320 female patients with VVC and were identified using both phenotypic and molecular methods. Their genotypes were determined, based on the presence or absence of a transposable intron in the 25S rDNA.ResultsEighty four (84) strains were recognized as being C. albicans and all the 84 C. albicans strains resulted to be genotype A. Antifungal susceptibility testing showed that 13 of those isolates (15.48%) were resistant to fluconazole.ConclusionsBased on these data, we concluded that C. albicans genotype A was common among VVC patients in Jos, and resistance to fluconazole is quite high. To our knowledge, this is the first study that reports C. albicans genotypes in Jos and its resistance to fluconazole. 相似文献
17.
Javier Andrés Bustamante-Rengifo Andrés Januer Matta Alvaro Pazos Luis Eduardo Bravo 《World journal of gastroenterology : WJG》2013,19(36):6044-6054
AIM:To evaluate the in vitro effect of amoxicillin and clarithromycin on the cag pathogenicity island(cag PAI).METHODS:One hundred and forty-nine clinical isolates of Helicobacter pylori(H.pylori)cultured from gastric biopsies from 206 Colombian patients with dyspeptic symptoms from a high-risk area for gastric cancer were included as study material.Antimicrobial susceptibility was determined by the agar dilution method.Resistant isolates at baseline and in amoxicillin and clarithromycin serial dilutions were subjected to genotyping(cagA,vacA alleles s and m),Glu-Pro-Ile-Tyr-Ala(EPIYA)polymerase chain reaction and random amplified polymorphic DNA(RAPD).Images of the RAPD amplicons were analyzed by Gel-Pro Analyzer 4.5program.Cluster analyses was done using SPSS 15.0statistical package,where each of the fingerprint bands were denoted as variables.Dendrograms were designed by following Ward’s clustering method and the estimation of distances between each pair of H.pylori isolates was calculated with the squared Euclidean distance.RESULTS:Resistance rates were 4%for amoxicillin and 2.7%for clarithromycin with 2%double resistances.Genotyping evidenced a high prevalence of the genotype cagA-positive/vacA s1m1.The 3’region of cagA gene was successfully amplified in 92.3%(12/13)of the baseline resistant isolates and in 60%(36/60)of the resistant isolates growing in antibiotic dilutions.Upon observing the distribution of the number of EPIYA repetitions in each dilution with respect to baseline isolates,it was found that in 61.5%(8/13)of the baseline isolates,a change in the number of EPIYA repetitions lowered antibiotic pressure.The gain and loss of EPIYA motifs resulted in a diversity of H.pylori subclones after bacterial adjustment to changing conditions product of antibiotic pressure.RAPD PCR evidenced the close clonal relationship between baseline isolates and isolates growing in antibiotic dilutions.CONCLUSION:Antibiotic pressure does not induce loss of the cag pathogenicity island,but it can leadin most cases- 相似文献
18.
Patricia J Baudry-Simner Amanpreet Singh James A Karlowsky Daryl J Hoban George G Zhanel the Canadian Antimicrobial Resistance Alliance 《The Canadian Journal of Infectious Diseases & Medical Microbiology》2012,23(3):e60-e64
OBJECTIVE:
To determine whether plasmid-mediated quinolone resistance (PMQR) determinants play a role in the increasing resistance to fluoroquinolones among Escherichia coli isolates in Canadian hospitals, and to determine the mechanisms of reduced susceptibility to ciprofloxacin in a recent collection of 190 clinical E coli isolates.METHODS:
E coli isolates (n=1702) were collected as part of the 2007 Canadian Hospital Ward Antibiotic Resistance Surveillance (CANWARD) study. Antimicrobial susceptibility testing was performed by Clinical and Laboratory Standards Institute (CLSI) broth microdilution. Using a representative subset of isolates (n=190), the mechanisms of reduced susceptibility to ciprofloxacin were detected by polymerase chain reaction and sequencing of the quinolone resistance-determining regions (QRDR) of chromosomal gyrA and parC genes, and by polymerase chain reaction for the PMQR genes: qnr, aac(6′) Ib-cr and qepA.RESULTS:
2.1% and 1.1% of E coli harboured aac(6′)Ib-cr and qnrB, respectively. Single amino acid substitutions in the QRDR of gyrA were observed among isolates with ciprofloxacin minimum inhibitory concentrations as low as 0.12 μg/mL. As the ciprofloxacin minimum inhibitory concentration increased to 1 μg/mL (which is still considered to be susceptible by the CLSI), the vast majority of isolates demonstrated both gyrA and parC mutations.CONCLUSION:
PMQR determinants and QRDR mutants among clinical E coli isolates with reduced susceptibility to ciprofloxacin demonstrates the need for increased surveillance and the need to re-evaluate the current CLSI breakpoints to prevent further development of fluoroquinolone resistance. 相似文献19.
Jeferson da Silva Junior Cláudio Daniel Cerdeira Juliana Moscardini Chavasco Ana Beatriz Pugina Cintra Carla Brigag?o Pacheco da Silva Andreia Natan de Mendon?a Tati Ishikawa Marcelo Fabiano Gomes Boriollo Jorge Kleber Chavasco 《Revista do Instituto de Medicina Tropical de S?o Paulo》2014,56(4):333-340
Currently multiresistant Staphylococcus aureus is one
common cause of infections with high rates of morbidity and mortality worldwide,
which directs scientific endeavors in search for novel antimicrobials. In this study,
nine extracts from Bidens pilosa (root, stem, flower and leaves) and
Annona crassiflora (rind fruit, stem, leaves, seed and pulp) were
obtained with ethanol: water (7:3, v/v) and their in vitro
antibacterial activity evaluated through both the agar diffusion and broth
microdilution methods against 60 Oxacillin Resistant S. aureus
(ORSA) strains and against S. aureus ATCC6538. The extracts from
B. pilosa and A. crassiflora inhibited the
growth of the ORSA isolates in both methods. Leaves of B. pilosa
presented mean of the inhibition zone diameters significantly higher than
chlorexidine 0.12% against ORSA, and the extracts were more active against S.
aureus ATCC (p < 0.05). Parallel, toxicity testing by
using MTT method and phytochemical screening were assessed, and three extracts
(B. pilosa, root and leaf, and A. crassiflora,
seed) did not evidence toxicity. On the other hand, the cytotoxic concentrations
(CC50 and CC90) for other extracts ranged from 2.06 to 10.77
mg/mL. The presence of variable alkaloids, flavonoids, tannins and saponins was
observed, even though there was a total absence of anthraquinones. Thus, the extracts
from the leaves of B. pilosa revealed good anti-ORSA activity and
did not exhibit toxicity. 相似文献
20.
Larissa Anuska Zeni CONDAS Márcio Garcia RIBEIRO Marisol Domingues MURO Agueda Palmira Castagna de VARGAS Tetsuhiro MATSUZAWA Katsukiyo YAZAWA Amanda Keller SIQUEIRA Tatiana SALERNO Gustavo Henrique Batista LARA Rafaela Mastrangelo RISSETI Karen Spadari FERREIRA Tohru GONOI 《Revista do Instituto de Medicina Tropical de S?o Paulo》2015,57(3):251-256
Nocardia is a ubiquitous microorganism related to pyogranulomatous
infection, which is difficult to treat in humans and animals. The occurrence of the
disease is on the rise in many countries due to an increase in immunosuppressive
diseases and treatments. This report of cases from Brazil presents the genotypic
characterization and the antimicrobial susceptibility pattern using the
disk-diffusion method and inhibitory minimal concentration with E-test® strips. In
summary, this report focuses on infections in young adult men, of which three cases
were cutaneous, two pulmonary, one neurological and one systemic. The pulmonary,
neurological and systemic cases were attributed to immunosuppressive diseases or
treatments. Sequencing analysis of the 16S rRNA segments (1491 bp) identified four
isolates of Nocardia farcinica, two isolates of Nocardia
nova and one isolate of Nocardia asiatica. N.
farcinica was involved in two cutaneous, one systemic and other pulmonary
cases; N. nova was involved in one neurological and one pulmonary
case; and Nocardia asiatica in one cutaneous case. The
disk-diffusion antimicrobial susceptibility test showed that the most effective
antimicrobials were amikacin (100%), amoxicillin/clavulanate (100%), cephalexin
(100%) and ceftiofur (100%), while isolates had presented most resistance to
gentamicin (43%), sulfamethoxazole/trimethoprim (43%) and ampicillin (29%). However,
on the inhibitory minimal concentration test (MIC test), only one of the four
isolates of Nocardia farcinica was resistant to
sulfamethoxazole/trimethoprim. 相似文献