bluuebunny/crossref_metadata_2025_split huggingface dataset:
Family portrait of Bacillus cereus and Bacillus weihenstephanensis cereulide‐producing strains
Authors: Hoton Florence M. , Fornelos Nadine , N'Guessan Elise , Hu Xiaomin , Swiecicka Izabela , Dierick Katelijne , Jääskeläinen Elina , Salkinoja‐Salonen Mirja , Mahillon Jacques 
Published: March 2009

SummaryTwo thousand Bacillus cereus sensu lato isolates from food and environmental matrices were screened by PCR for the presence of cereulide‐producing strains. This survey identified 73 potential emetic strains, most of which originated from non‐random food and clinical samplings. None of the 460 Bacillus thuringiensis, Bacillus mycoides and Bacillus pseudomycoides strains were PCR‐positive for the cereulide genetic determinants. The chromosomal and extrachromosomal gene pool diversity of a subset of 30 cereulide‐producing strains was then assessed using multilocus sequence typing, large plasmid gel electrophoresis and Southern blot hybridization. The strain toxicity on boar sperm and cereulide production were also analysed. The most striking observation was the identification of two distinct clusters of cereulide‐producing strains, with members of the second group (cluster II) identified as psychrotolerant B. weihenstephanensis able to grow at 8°C. Moreover, the location of the cereulide genetic determinants was shown to vary depending on the strain, indicating a probable genomic mobility.
Genetic Determinants of Resistance to Fusidic Acid among Clinical Bacteremia Isolates of
Staphylococcus aureus
Authors: Lannergård Jonas , Norström Tobias , Hughes Diarmaid 
Published: March 2009

ABSTRACT

Resistance to fusidic acid in
Staphylococcus aureus
is caused by mutation of the elongation factor G (EF-G) drug target (FusA class) or by expression of a protein that protects the drug target (FusB and FusC classes). Recently, two novel genetic classes of small-colony variants (SCVs) were identified among fusidic acid-resistant mutants selected in vitro (FusA-SCV and FusE classes). We analyzed a phylogenetically diverse collection of fusidic acid-resistant bacteremia isolates to determine which resistance classes were prevalent and whether these were associated with particular phylogenetic lineages. Each isolate was shown by DNA sequencing and plasmid curing to carry only one determinant of fusidic acid resistance, with approximately equal frequencies of the FusA, FusB, and FusC genetic classes. The FusA class (mutations in
fusA
) were distributed among different phylogenetic types. Two distinct variants of the FusC class (chromosomal
fusC
gene) were identified, and FusC was also distributed among different phylogenetic types. In contrast, the FusB class (carrying
fusB
on a plasmid) was found in closely related types. No FusE-class mutants (carrying mutations in
rplF
) were found. However, one FusA-class isolate had multiple mutations in the
fusA
gene, including one altering a codon associated with the FusA-SCV class. SCVs are frequently unstable and may undergo compensatory evolution to a normal growth phenotype after their initial occurrence. Accordingly, this normal-growth isolate might have evolved from a fusidic acid-resistant SCV. We conclude that at least three different resistance classes are prevalent among fusidic acid-resistant bacteremia isolates of
S. aureus
.
Quasiexperimental Study of the Effects of Antibiotic Use, Gastric Acid-Suppressive Agents, and Infection Control Practices on the Incidence of
Clostridium difficile
-Associated Diarrhea in Hospitalized Patients
Authors: Aldeyab Mamoon A. , Harbarth Stephan , Vernaz Nathalie , Kearney Mary P. , Scott Michael G. , Funston Chris , Savage Karen , Kelly Denise , Aldiab Motasem A. , McElnay James C. 
Published: March 2009

ABSTRACT

The objective of this study was to evaluate the effects of antimicrobial drug use, gastric acid-suppressive agent use, and infection control practices on the incidence of
Clostridium difficile
-associated diarrhea (CDAD) in a 426-bed general teaching hospital in Northern Ireland. The study was retrospective and ecological in design. A multivariate autoregressive integrated moving average (time-series analysis) model was built to relate CDAD incidence with antibiotic use, gastric acid-suppressive agent use, and infection control practices within the hospital over a 5-year period (February 2002 to March 2007). The findings of this study showed that temporal variation in CDAD incidence followed temporal variations in expanded-spectrum cephalosporin use (average delay = 2 months; variation of CDAD incidence = 0.01/100 bed-days), broad-spectrum cephalosporin use (average delay = 2 months; variation of CDAD incidence = 0.02/100 bed-days), fluoroquinolone use (average delay = 3 months; variation of CDAD incidence = 0.004/100 bed-days), amoxicillin-clavulanic acid use (average delay = 1 month; variation of CDAD incidence = 0.002/100 bed-days), and macrolide use (average delay = 5 months; variation of CDAD incidence = 0.002/100 bed-days). Temporal relationships were also observed between CDAD incidence and use of histamine-2 receptor antagonists (H2RAs; average delay = 1 month; variation of CDAD incidence = 0.001/100 bed-days). The model explained 78% of the variance in the monthly incidence of CDAD. The findings of this study highlight a temporal relationship between certain classes of antibiotics, H2RAs, and CDAD incidence. The results of this research can help hospitals to set priorities for restricting the use of specific antibiotic classes, based on the size-effect of each class and the delay necessary to observe an effect.
Mechanisms of the Hepatic Acute-Phase Response during Bacterial Pneumonia
Authors: Quinton Lee J. , Jones Matthew R. , Robson Bryanne E. , Mizgerd Joseph P. 
Published: March 2009

ABSTRACT

The acute-phase response is characterized by increased circulating levels of acute-phase proteins (APPs) generated by the liver. During bacterial pneumonia, APPs correlate with the severity of disease, serve as biomarkers, and are functionally significant. The kinetics and regulatory mechanisms of APP induction in the liver during lung infection have yet to be defined. Here we show that APP mRNA transcription is induced in the livers of mice whose lungs are infected with either
Escherichia coli
or
Streptococcus pneumoniae
, and that in both cases this induction occurs in tandem with activation in the liver of the transcription factors signal transducer and activator of transcription 3 (STAT3) and NF-κB RelA. Interleukin-6 (IL-6) deficiency inhibited the activation of STAT3 and the induction of select APPs in the livers of pneumonic mice. Furthermore, liver RelA activation and APP induction were reduced for mice lacking all signaling receptors for tumor necrosis factor alpha and IL-1. In a murine hepatocyte cell line, knockdown of either STAT3 or RelA by small interfering RNA inhibited cytokine induction of the APP serum amyloid A-1, demonstrating that both transcription factors were independently essential for the expression of this gene. These data suggest that during pneumonia caused by gram-negative or gram-positive bacteria, the expression of APPs in the liver depends on STAT3 activation by IL-6 and on RelA activation by early-response cytokines. These signaling axes may be critical for integrating systemic responses to local infection, balancing antibacterial host defenses and inflammatory injury during acute bacterial pneumonia.
Resistance ofHaemophilus influenzaeto Reactive Nitrogen Donors and Gamma Interferon-Stimulated Macrophages Requires the Formate-Dependent Nitrite Reductase Regulator-ActivatedytfEGene
Authors: Harrington Jane C. , Wong Sandy M. S. , Rosadini Charles V. , Garifulin Oleg , Boyartchuk Victor , Akerley Brian J. 
Published: March 2009

ABSTRACTHaemophilus influenzaeefficiently colonizes and persists at the human nasopharyngeal mucosa, causing disease when it spreads to other sites. Nitric oxide (NO) represents a major antimicrobial defense deployed by host cells in locations colonized byH. influenzaeduring pathogenesis that are likely to vary in oxygen levels. Formate-dependent nitrite reductase regulator (FNR) is an oxygen-sensitive regulator in several bacterial pathogens. We report thatfnrofH. influenzaeis required for anaerobic defense against exposure to NO donors and to resist NO-dependent effects of gamma interferon (IFN-γ)-activated murine bone marrow-derived macrophages. To understand the mechanism of resistance, we investigated the role of FNR-regulated genes in defense against NO sources. Expression analysis revealed FNR-dependent activation ofnrfA,dmsA,napA, andytfE. Nonpolar deletion mutants ofnrfAandytfEexhibited sensitivity to NO donors, and theytfEgene was more critical for survival. Compared to the wild-type strain, theytfEmutant exhibited decreased survival when exposed to macrophages, a defect that was more pronounced after prior stimulation of macrophages with IFN-γ or lipopolysaccharide. Complementation restored survival of the mutant to the level in the parental strain. Increased sensitivity of theytfEmutant relative to that of the parent was abrogated by treatment of macrophages with a NO synthase inhibitor, implicating YtfE in resistance to a NO-dependent pathway. These results identify a requirement for FNR in positive control ofytfEand indicate a critical role forytfEin resistance ofH. influenzaeto reactive nitrogen species and the antibacterial effects of macrophages.
Role of HrpA in Biofilm Formation of
Neisseria meningitidis
and Regulation of the
hrpBAS
Transcripts
Authors: Neil R. Brock , Apicella Michael A. 
Published: March 2009

ABSTRACT

Two-partner secretion systems of gram-negative organisms are utilized in adherence, invasion, and biofilm formation. The HrpAB proteins of
Neisseria meningitidis
are members of a two-partner secretion system, and HrpA is established as being important to adherence and intracellular escape. This study set out to determine the expression pattern of members of the
hrpBAS
putative operon and to find a functional role for the HrpA protein. The upregulation of these genes was found in situations of anaerobiosis and cell contact. These observations prompted the study of the function of HrpA in biofilms on human bronchial epithelial cells. HrpA mutants in encapsulated and unencapsulated NMB strains demonstrated biofilm growth equivalent to that of the wild-type strain at 6 h but a decreased ability to form biofilms at 48 h. Biofilms formed by
hrpA
mutants for 48 h on collagen-coated coverslips demonstrated significant reductions compared to those of wild-type strains. Taken together, these observations imply a role for HrpA in the biofilm structure. Further analysis demonstrated the presence of HrpA on the surface of the bacterium.
Rhinitis associated with pesticide exposure among commercial pesticide applicators in the Agricultural Health Study
Authors: Slager R E , Poole J A , LeVan T D , Sandler D P , Alavanja M C R , Hoppin J A 
Published: March 2009

Objectives:Rhinitis is common, but the risk factors are not well described. To investigate the association between current rhinitis and pesticide use, we used data from 2245 Iowa commercial pesticide applicators in the Agricultural Health Study.Methods:Using logistic regression models adjusted for age, education and growing up on a farm, we evaluated the association between current rhinitis and 34 pesticides used in the past year.Results:74% of commercial pesticide applicators reported at least one episode of rhinitis in the past year (current rhinitis). Five pesticides used in the past year were significantly positively associated with current rhinitis: the herbicides 2,4-D, glyphosate and petroleum oil, the insecticide diazinon and the fungicide benomyl. The association for 2,4-D and glyphosate was limited to individuals who used both in the past year (OR 1.42, 95% CI 1.14 to 1.77). Both petroleum oil and diazinon showed consistent evidence of an association with rhinitis, based on both current use and exposure–response models. We saw no evidence of confounding by common agricultural rhinitis triggers such as handling grain or hay.Conclusions:Exposure to pesticides may increase the risk of rhinitis.
Helicobacter pyloridetection and genotyping in gastric biopsy specimens from Chennai patients (India)
Authors: Udhayakumar Gopal , Senthilkumar Cinghu , Jayanthi Venkatraman , Devaraj Niranjali , Devaraj Halagowder 
Published: March 2009

The aim of the present study was to investigate the prevalence of Helicobacter pylori infection and the correlation between cagA and vacA (mid-region) genotypes with different clinical outcomes from Chennai, India, patients. Biopsies from the antrum were taken to assess the current H. pylori status by histology, rapid urease test (RUT), and PCR. The RUT and PCR analyses were carried out on a single biopsy specimen. Fasting sera were obtained from all patients and H. pylori status was determined by using ELISA. In addition, the correlations between cagA and vacA genotypes and the consequence of H. pylori infection were statistically examined. Prevalence of the cagA gene was found in 96% (90/94) of patients, and the vacA m2 subtype occurred in 60% (56/94), whereas 32% (30/94) showed the vacA m1 subtype. A significant association between the cagA and vacA m2 region (χ2 = 5.556; p < 0.01) was found in ulcer patients. The vacA m2 genotype showed a near-significant value (χ2 = 3.943; p < 0.047) in ulcer patients when compared with vacA m1. These findings suggest that H. pylori strains with the vacA m2 region were predominant in South India, especially in and around Chennai. This study also showed that PCR has a potential value for studying the cagA gene directly from biopsy specimens.
Biofilm evidence and the microbial diversity of horse wounds
Authors: Cochrane Christine A. , Freeman Karen , Woods Emma , Welsby Sarah , Percival Steven L. 
Published: March 2009

Evidence of biofilms in human chronic wounds are thought to be responsible for preventing healing in a timely manner. However, biofilm evidence in horse wounds has not yet been documented. Consequently, this study aimed to determine whether biofilms could be detected in wounds, and to investigate the microbiology of chronic wounds in horses. Prior to analysis, wound surfaces were irrigated with 5 mL of sterile saline to remove debris. All wounds were swabbed twice (1 cm2area) using sterile cotton-tipped swabs. In addition to this, 2 tissue biopsies were taken to investigate evidence of biofilm and the microbiology richness of the wounds. All swabs and 1 biopsy sample were transported to the laboratory in Robertson’s cooked meat broth. Traditional culturable techniques and denaturing gradient gel electrophoresis with PCR were utilized to identify common bacteria isolated in all wounds. Following analysis of a number of the biopsy samples, biofilms could be clearly seen. The most common bacteria isolated from each wound analysed included Pseudomonas aeruginosa , Staphylococcus epidermidis , Serratia marcescens , Enterococcus faecalis , and Providencia rettgeri . Sequencing of the 16S ribosmonal DNAs, selected on the basis of DGGE profiling, enabled identification of bacterial species not identified using culturable technology. This study is the first to identify biofilms in the chronic wounds of horses. In addition, this study also demonstrated the importance of combining DGGE–PCR with culture techniques to provide better microbiology analysis of chronic wounds.
Effect of stimulation frequency on force, net power output, and fatigue in mouse soleus muscle in vitro
Authors: Vassilakos George , James Rob. S. , Cox Valerie M. 
Published: March 2009

The effects of electrical stimulation frequency on force, work loop power output, and fatigue of mouse soleus muscle were investigated in vitro at 35 °C. Increasing stimulation frequency did not significantly affect maximal isometric tetanic stress (overall mean ± SD, 205 ± 16.6 kN·m–2between 70 and 160 Hz) but did significantly increase the rate of force generation. The maximal net power output during work loops significantly increased with stimulation frequency: 18.2 ± 3.7, 22.5 ± 3.3, 26.8 ± 3.7, and 28.6 ± 3.4 W·kg–1at 70, 100, 130, and 160 Hz, respectively. The stimulation frequency that was used affected the pattern of fatigue observed during work loop studies. At stimulation frequencies of 100 and 130 Hz, there were periods of mean net negative work during the fatigue tests due to a slowing of relaxation rate. In contrast, mean net work remained positive throughout the fatigue test when stimulation frequencies of 70 and 160 Hz were used. The highest cumulative work during the fatigue test was performed at 70 and 160 Hz, followed by 130 Hz, then 100 Hz. Therefore, stimulation frequency affects power output and the pattern of fatigue in mouse soleus muscle.
Ambient temperature is more important than food availability in explaining reproductive timing of the bat Sturnira lilium (Mammalia: Chiroptera) in a montane Atlantic Forest
Authors: Mello M.A.R. , Kalko E.K.V. , Silva W.R. 
Published: March 2009

Reproduction of bats is determined by a suite of endogenous and exogenous factors. Among exogenous influences, special attention has been given to the influence of food availability. However, in highland forests, severe decreases in temperature during the cold and dry season may also play an important role. In the present study we tested the influence of ambient temperature and food availability on the timing of reproduction in the frugivorous bat Sturnira lilium (E. Geoffroy, 1810). We conducted a 15-month mist-netting sampling in a mountain area of the Brazilian Atlantic Forest during which time we assessed the bats’ diet through fecal samples, monitored fruit production of the main food plants, and recorded variations in ambient temperature. Sturnira lilium fed almost exclusively on Solanaceae. Similarly to the lowlands, reproduction was bimodal, but reproductive season tended to be shorter in the highlands and peaked in the warmer months of the year. Overall, 44% to 53% of the reproductive pattern was explained by variations in ambient temperature, while the relationship with food availability was nonsignificant. We conclude that variations in ambient temperature in tropical mountains may be a stronger selection pressure than food availability in determining reproductive timing of bats.
Arthroscopic Rotator Cuff Repair Using the Opus Knotless Suture Anchor Fixation System
Authors: Redziniak Daniel E. , Hart Joseph , Turman Kim , Treme Gehron , Hart Jennifer , Lunardini David , Miller Mark D. , Diduch David R. 
Published: March 2009

Background The reported failure rate of arthroscopic rotator cuff repair varies widely. The influence of repair technique on failure rates and functional outcomes after arthroscopic cuff repair remains controversial. Purpose To determine the functional outcome of arthroscopic knotless fixation using the Opus AutoCuff device for rotator cuff repair and to compare our results with those reported in the literature. Study Design Case series; Level of evidence, 4. Methods Fifty-six consecutive patients underwent arthroscopic rotator cuff repair using an Opus AutoCuff device (Arthrocare, Sunnydale, California) with greater than 2 years’ follow-up. Subjective and objective clinical examinations were performed to include the University of California at Los Angeles (UCLA) shoulder score, the American Shoulder and Elbow Surgeons (ASES) rating scale, the visual analog scale (VAS), and the Tegner Activity Level scale. Results Forty-eight patients were evaluated at a mean follow-up of 26 months (range, 24–35 months). The mean UCLA shoulder score was 33.1 of 35 (SD, 2.89) possible points, and the mean ASES rating scale was 94.2 of 100 (SD, 7.76) compared with a mean preoperative score of 65.7 ( P < .001). Postoperative UCLA shoulder scores had 42 of 45 (93.3%) patients with good and excellent results. The mean preoperative ASES pain score was 1.3 (SD, 1.0), and the mean postoperative score was 4.4 (SD, 1.0) ( P < .001). The Tegner Activity Level scores demonstrated restoration of function to preinjury status. There were 3 failures (6.3%), 2 by anchor failure (1 with specific trauma), and 1 by rotator cuff retear, all requiring revision surgery. Conclusion Arthroscopic knotless suture fixation with the Opus AutoCuff device results in good to excellent results similar to those reported in the literature with conventional suture anchors.
Polymorphisms of the ß2 adrenoreceptor gene in chronic obstructive pulmonary disease
Authors: Vacca Gabriela , Schwabe Kerstin , Dück Ramona , Hlawa Hans-Peter , Westphal Arite , Pabst Stefan , Grohé Christian , Gillissen Adrian 
Published: March 2009

Background: The ß2-adrenergic receptors are cell surface receptors playing a central role in the pharmacological targeting asthma and chronic obstructive pulmonary disease (COPD). Recent studies suggest that patients who are homozygous for one of the two important polymorphisms of the ß2-adrenergic receptor (ADRB2) gene at codon 16 (arginine to glycine) and 27 (glutamine to glutamate) may have a reduced response to ß2-agonists. Since smoking patients who are Gly16 homozygotes have an increased risk of airway obstruction we hypothesized that ß2-adrenoreceptor gene polymorphisms may be also a cofounder for COPD development and disease severity. Methods: We investigated 190 COPD patients and 172 healthy volunteers in a case-control study. DNA was isolated from whole blood and ß2-AR gene polymorphisms Arg/Gly16 and Gln/Glu27 were determined using allele-specific polymerase chain reaction (PCR). Results: In COPD patients with Gly/Gly16 was found more frequently than in healthy smokers (29.47% COPD versus 18.18% controls, p = 0.026). All other gene polymorphisms of the ADRB2 gene at codon 16 were equally distributed between groups. ß2-adrenoreceptor gene polymorphisms were neither a cofounder for COPD exacerbations (≥ 3 hospitalizations within the last 3 years) nor for disease severity (FEV1 ≤ 30% predicted). Conclusion: Our study suggests that the Gly16 allele of the ß2-AR gene predisposes to COPD development but not for exacerbation rates and disease severity. In contrast, Gln/Glu27 polymorphism was irrelevant in our COPD cohort.
The favorable impact of CEBPA mutations in patients with acute myeloid leukemia is only observed in the absence of associated cytogenetic abnormalities and FLT3 internal duplication
Authors: Renneville Aline , Boissel Nicolas , Gachard Nathalie , Naguib Dina , Bastard Christian , de Botton Stéphane , Nibourel Olivier , Pautas Cécile , Reman Oumedaly , Thomas Xavier , Gardin Claude , Terré Christine , Castaigne Sylvie , Preudhomme Claude , Dombret Hervé 
Published: March 2009

AbstractMutations of the CCAAT/enhancer binding protein alpha (CEBPA) gene have been associated with a favorable outcome in patients with acute myeloid leukemia (AML), but mainly in those with a normal karyotype. Here, we analyzed the impact of associated cytogenetic abnormalities or bad-prognosis fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) in 53 patients with CEBPA+ de novo AML treated in the Acute Leukemia French Association trials. We found that only those with a normal karyotype and no FLT3-ITD displayed the expected favorable outcome. In this context, relapse-free, disease-free, and overall survival were significantly longer than in corresponding patients without the CEBPA mutation (P = .035, .016, and .047, respectively). This was not observed in the context of an abnormal karyotype or associated FLT3-ITD. Furthermore, after adjustment on age, trial, and mutation type, these features were independently predictive of shorter overall survival in the subset of patients with CEBPA+ AML (multivariate hazard ratio = 2.7; 95% confidence interval, 1.08-6.7; and 2.9; 95% confidence interval, 1.01-8.2; with P = .034 and .05, for abnormal karyotype and FLT3-ITD, respectively).