Metabolomics responses and tolerance of Pseudomonas aeruginosa under acoustic vibration stress

Sound has been shown to impact microbial behaviors. However, our understanding of the chemical and molecular mechanisms underlying these microbial responses to acoustic vibration is limited. In this study, we used untargeted metabolomics analysis to investigate the effects of 100-Hz acoustic vibration on the intra- and extracellular hydrophobic metabolites of P. aeruginosa PAO1. Our findings revealed increased levels of fatty acids and their derivatives, quinolones, and N-acylethanolamines upon sound exposure, while rhamnolipids (RLs) showed decreased levels. Further quantitative real-time polymerase chain reaction experiments showed slight downregulation of the rhlA gene (1.3-fold) and upregulation of fabY (1.5-fold), fadE (1.7-fold), and pqsA (1.4-fold) genes, which are associated with RL, fatty acid, and quinolone biosynthesis. However, no alterations in the genes related to the rpoS regulators or quorum-sensing networks were observed. Supplementing sodium oleate to P. aeruginosa cultures to simulate the effects of sound resulted in increased tolerance of P. aeruginosa in the presence of sound at 48 h, suggesting a potential novel response-tolerance correlation. In contrast, adding RL, which went against the response direction, did not affect its growth. Overall, these findings provide potential implications for the control and manipulation of virulence and bacterial characteristics for medical and industrial applications.

Microtiter plate with built-in oxygen sensors: a novel approach to investigate the dynamics of Pseudomonas aeruginosa growth suppression in the presence of divalent cations and antibiotics

The depletion of dissolved oxygen in a defined synthetic medium can be measured in real time, using a micro-well plate format, associated with a fluorescent plate reader. This technology is appropriate for investigating the effect of antibiotics on cell kinetics because there is a direct correlation between the latter and the amount of dissolved oxygen in the medium of an assay. In this study, the metabolic activity of the opportunistic human pathogen Pseudomonas aeruginosa PA01 was investigated using the OxoPlate OP96U optical sensor technology. The response of P. aeruginosa to aminoglycoside antibiotics when Ca²⁺and Mg²⁺ ions are present in the Evans defined synthetic medium was measured. The results revealed that the effect of antibiotics on P. aeruginosa is influenced by the concentration of divalent cations present in the test medium, although the efficiency of Ca²⁺ in supressing antibiotic activity was found to be greater than that of Mg²⁺. By comparison to tobramycin, the effect of amikacin is largely inhibited by the Ca²⁺and Mg²⁺concentrations. The study results underscore that the reliability of the observation of growth inhibitors is enhanced by the oxygen consumption measurements. Thus, the OxoPlate OP96U system is proven to be an accurate method to test the effectiveness of antibiotic treatments against P. aeruginosa.

A novel air-dried multiplex high-resolution melt assay for the detection of extended-spectrum β-lactamase and carbapenemase genes

OBJECTIVES

This study aimed to develop and evaluate a novel air-dried high-resolution melt (HRM) assay to detect eight major extended-spectrum β-lactamase (ESBL) (blaSHV and blaCTX-M groups 1 and 9) and carbapenemase (blaNDM, blaIMP, blaKPC, blaVIM and blaOXA-48-like) genes that confer resistance to cephalosporins and carbapenems.

METHODS

The assay was evaluated using 439 DNA samples extracted from bacterial isolates from Nepal, Malawi and the UK and 390 clinical isolates from Nepal with known antimicrobial susceptibility. Assay reproducibility was evaluated across five different real-time quantitative PCR (qPCR) instruments [Rotor-Gene® Q, QuantStudioTM 5, CFX96, LightCycler® 480 and Magnetic Induction Cycler (Mic)]. Assay stability was also assessed under different storage temperatures (6.2 ± 0.9°C, 20.4 ± 0.7°C and 29.7 ± 1.4°C) at six time points over 8 months.

RESULTS

The sensitivity and specificity (with 95% confidence intervals) for detecting ESBL and carbapenemase genes was 94.7% (92.5-96.5%) and 99.2% (98.8-99.5%) compared with the reference gel-based PCR and sequencing and 98.3% (97.0-99.3%) and 98.5% (98.0-98.9%) compared with the original HRM wet PCR mix format. Overall agreement was 91.1% (90.0-92.9%) when predicting phenotypic resistance to cefotaxime and meropenem among Enterobacteriaceae isolates. We observed almost perfect inter-machine reproducibility of the air-dried HRM assay, and no loss of sensitivity occurred under all storage conditions and time points.

CONCLUSION

We present a ready-to-use air-dried HRM PCR assay that offers an easy, thermostable, fast and accurate tool for the detection of ESBL and carbapenemase genes in DNA samples to improve antimicrobial resistance detection.

Persister cells: formation, resuscitation and combative therapies

Persister cells, or superfits, have been strongly implicated in the recalcitrance and recurrence of chronic bacterial infection through the dormant (metabolically reduced) phenotype they display and the tolerance to antimicrobial agents this dormancy grants them. The complex biochemical events that lead to the formation of persister cells are not completely understood, though much research has linked the degradation of type II toxin/antitoxin systems and reduced cellular ATP levels to the rise in stress response molecules (where (p)ppGpp is of particular interest), which induce this dormant state. The equally complex mechanism of resuscitation is initiated by the cells’ ability to sense nutrient availability via chemotaxis systems. Levels of secondary messenger proteins (i.e., cAMP) within the cell are reduced to allow the resuscitation of ribosomes, by ribosomal resuscitation factor HflX, to reinstate protein synthesis and, therefore, growth to re-populate. Techniques of superfit eradication utilise one, or more, of three approaches (i) direct killing, (ii) re-sensitising persister cells to conventional antimicrobials, or (iii) prevention of persister formation though few laboratory findings have been translated to clinical practice. This work will outline current findings in the field with a critical approach, where possible.

A bimodal burst energy distribution of a repeating fast radio burst source

The event rate, energy distribution and time-domain behaviour of repeating fast radio bursts (FRBs) contain essential information regarding their physical nature and central engine, which are as yet unknown^1,2. As the first precisely localized source, FRB 121102 (refs. ^3-5) has been extensively observed and shows non-Poisson clustering of bursts over time and a power-law energy distribution^6-8. However, the extent of the energy distribution towards the fainter end was not known. Here we report the detection of 1,652 independent bursts with a peak burst rate of 122 h^-1, in 59.5 hours spanning 47 days. A peak in the isotropic equivalent energy distribution is found to be approximately 4.8 × 10³⁷ erg at 1.25 GHz, below which the detection of bursts is suppressed. The burst energy distribution is bimodal, and well characterized by a combination of a log-normal function and a generalized Cauchy function. The large number of bursts in hour-long spans allows sensitive periodicity searches between 1 ms and 1,000 s. The non-detection of any periodicity or quasi-periodicity poses challenges for models involving a single rotating compact object. The high burst rate also implies that FRBs must be generated with a high radiative efficiency, disfavouring emission mechanisms with large energy requirements or contrived triggering conditions.

A highly multiplexed melt-curve assay for detecting the most prevalent carbapenemase, ESBL, and AmpC genes

Resistance to third-generation cephalosporins and carbapenems in Gram-negative bacteria is chiefly mediated by beta-lactamases including extended-spectrum beta-lactamase (ESBL), AmpC, and carbapenemase enzymes. Routine phenotypic detection methods do not provide timely results, and there is a lack of comprehensive molecular panels covering all important markers. An ESBL/carbapenemase high-resolution melt analysis (HRM) assay (SHV, TEM, CTX-M ESBL families, and NDM, IMP, KPC, VIM and OXA-48-like carbapenemases) and an AmpC HRM assay (16S rDNA control, FOX, MOX, ACC, EBC, CIT, and DHA) were designed and evaluated on 111 Gram-negative isolates with mixed resistance patterns. The sensitivity for carbapenemase, ESBL, and AmpC genes was 96.7% (95% confidence interval [CI]: 82.8-99.9%), 93.6% (95% CI: 85.7-97.9%), and 93.8% (95% CI: 82.8-98.7%), respectively, with a specificity of 100% (95% CI: 95.6-100%), 93.9% (95% CI: 79.8-99.3%), and 93.7% (95% CI: 84.5-98.2%). The HRM assays enable the simultaneous detection of the 14 most important ESBL, carbapenemase, and AmpC genes and could be used as a molecular surveillance tool or to hasten detection of antimicrobial resistance for treatment management.

Abnormally reduced primary motor cortex output is related to impaired hand function in chronic stroke

Stroke often involves primary motor cortex (M1) and its corticospinal projections (CST). As hand function is critically dependent on these structures, its recovery is often incomplete. The neuronal substrate supporting affected hand function is not well understood but likely involves reorganized M1 and CST of the lesioned hemisphere (M1_IL and CST_IL). We hypothesized that affected hand function in chronic stroke is related to structural and functional reorganization of M1_IL and CST_IL. We tested 18 patients with chronic ischemic stroke involving M1 or CST. Their hand function was compared with 18 age-matched healthy subjects. M1_IL thickness and CST_IL fractional anisotropy (FA) were determined with MRI and compared with measures of the other hemisphere. Transcranial magnetic stimulation (TMS) was applied to M1_IL to determine its input-output function [stimulus response curve (SRC)]. The plateau of the SRC (MEPmax), inflection point, and slope parameters of the curve were extracted. Results were compared with measures in 12 age-matched healthy controls. MEPmax of M1_IL was significantly smaller ( P = 0.02) in the patients, indicating reduced CST_IL motor output, and was correlated with impaired hand function ( P = 0.02). M1_IL thickness ( P < 0.01) and CST_IL-FA ( P < 0.01) were reduced but did not correlate with hand function. The results indicate that employed M1_IL or CST_IL structural measures do not explain the extent of impairment in hand function once M1 and CST are sufficiently functional for TMS to evoke a motor potential. Instead, impairment of hand function is best explained by the abnormally low output from M1_IL. NEW & NOTEWORTHY Hand function often remains impaired after stroke. While the critical role of the primary motor cortex (M1) and its corticospinal output (CST) for hand function has been described in the nonhuman primate stroke model, their structure and function have not been systematically evaluated for patients after stroke. We report that in chronic stroke patients with injury to M1 and/or CST an abnormally reduced M1 output is related to impaired hand function.

Speciation of common Gram-negative pathogens using a highly multiplexed high resolution melt curve assay

The identification of the bacterial species responsible for an infection remains an important step for the selection of antimicrobial therapy. Gram-negative bacteria are an important source of hospital and community acquired infections and frequently antimicrobial resistant. Speciation of bacteria is typically carried out by biochemical profiling of organisms isolated from clinical specimens, which is time consuming and delays the initiation of tailored treatment. Whilst molecular methods such as PCR have been used, they often struggle with the challenge of detecting and discriminating a wide range of targets. High resolution melt analysis is an end-point qPCR detection method that provides greater multiplexing capability than probe based methods. Here we report the design of a high resolution melt analysis assay for the identification of six common Gram-negative pathogens; Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa, Salmonella Sp, and Acinetobacter baumannii, and a generic Gram-negative specific 16S rRNA control. The assay was evaluated using a well characterised collection of 113 clinically isolated Gram-negative bacteria. The agreement between the HRM assay and the reference test of PCR and sequencing was 98.2% (Kappa 0.96); the overall sensitivity and specificity of the assay was 97.1% (95% CI: 90.1-99.7%) and 100% (95% CI: 91.78-100%) respectively.

Boesenbergia rotunda (L.) Mansf. extract potentiates the antibacterial activity of some β-lactams against β-lactam-resistant staphylococci

OBJECTIVES

The purpose of this study was to investigate the effect of Boesenbergia rotunda (L.) Mansf. extract (BRE) and peptidoglycan inhibitor antibiotics, alone and in combination, against β-lactam-resistant staphylococci.

METHODS

Antibacterial and synergistic activities of BRE alone and in combination with ampicillin (AMP), cloxacillin (CLX), cefazolin (CZO) or vancomycin (VAN) were evaluated against two β-lactam-resistant Staphylococcus aureus (BRSA) isolates and one β-lactam-resistant Staphylococcus epidermidis (BRSE) isolate. The activities were confirmed by killing curve assays. The preliminary antimicrobial action was elucidated by transmission electron microscopy (TEM) and cytoplasmic membrane (CM) permeability assay.

RESULTS

All tested staphylococci were inhibited by BRE at a minimum inhibitory concentration (MIC) of 16μg/mL. Two BRSA strains showed high resistance to CLX, AMP and CZO, whilst BRSE was resistant to CLX and AMP. All tested isolates remained susceptible to VAN. Chequerboard assay demonstrated a fractional inhibitory concentration index (FICI) of 0.50 for the BRE+CLX combination against the BRSA strains. Killing curve determinations confirmed the antibacterial and synergistic activities. TEM revealed collapse of the CM in BRE-treated cells and damage both of the CM and peptidoglycan (PG) in BRE+CLX-treated cells. The CM permeability assay showed that either BRE or nisin alone as well as BRE+CLX significantly induced leakage of OD_260nm-absorbing materials.

CONCLUSIONS

BRE potentiated the activity of β-lactams, particularly CLX, against β-lactam-resistant staphylococci by damaging the CM and PG layer, leading to leakage of intracellular material. Combination of BRE and β-lactams provides a potential way forward in developing novel antistaphylococcal agents.

The performance of a resazurin chromogenic agar plate with a combined disc method for rapid screening of extended-spectrum-β-lactamases, AmpC β-lactamases and co-β-lactamases in Enterobacteriaceae

A promising means of rapid screening of extended-spectrum-β-lactamase (ESBL), AmpC β-lactamase, and co-production of ESBL and AmpC that combines resazurin chromogenic agar (RCA) with a combined disc method is here reported. Cefpodoxime (CPD) discs with and without clavulanic acid (CA), cloxacillin (CX) and CA+CX were evaluated against 86 molecularly confirmed β-lactamase-producing Enterobacteriaceae, including 15 ESBLs, 32 AmpCs, nine co-producers of ESBL and AmpC and 30 carbapenemase producers. The CA and CX synergy test successfully detected all ESBL producers (100% sensitivity and 98.6% specificity) and all AmpC producers (100% sensitivity and 96.36% specificity). This assay also performed well in screening for co-existence of ESBL and AmpC (88.89% sensitivity and 100% specificity). The RCA assay is simple and inexpensive and provides results within 7 hr. It can be performed in any microbiological laboratory, in particular, in geographic regions in which ESBL, AmpC or co-β-lactamase-producing Enterobacteriaceae are endemic.

Synergism and the mechanism of action of the combination of α-mangostin isolated from Garcinia mangostana L. and oxacillin against an oxacillin-resistant Staphylococcus saprophyticus

Background

Globally, staphylococci have developed resistance to many antibiotics. New approaches to chemotherapy are needed and one such approach could be to use plant derived actives with conventional antibiotics in a synergestic way. The purpose of this study was to isolate α-mangostin from the mangosteen (Garcinia mangostana L.; GML) and investigate antibacterial activity and mechanisms of action when used singly and when combined with oxacillin against oxacillin-resistant Staphylococcus saprophyticus (ORSS) strains. The isolated α-mangostin was confirmed by HPLC chromatogram and NMR spectroscopy. The minimum inhibitory concentration (MIC), checkerboard and killing curve were determined. The modes of action of these compounds were also investigated by enzyme assay, transmission electron microscopy (TEM), confocal microscopic images, and cytoplasmic membrane (CM) permeabilization studies.

Results

The MICs of isolated α-mangostin and oxacillin against these strains were 8 and 128 μg/ml, respectively. Checkerboard assays showed the synergistic activity of isolated α-mangostin (2 μg/ml) plus oxacillin (16 μg/ml) at a fractional inhibitory concentration index (FICI) of 0.37. The kill curve assay confirmed that the viability of oxacillin-resistant Staphylococcus saprophyticus DMST 27055 (ORSS-27055) was dramatically reduced after exposure to isolated α-mangostin (2 μg/ml) plus oxacillin (16 μg/ml). Enzyme assays demonstrated that isolated α-mangostin had an inhibitory activity against β-lactamase in a dose-dependent manner. TEM results clearly showed that these ORSS-27055 cells treated with this combination caused peptidoglycan and cytoplasmic membrane damage, irregular cell shapes and average cell areas were significantly larger than the control. Clearly, confocal microscopic images confirmed that this combination caused considerable peptidoglycan damage and DNA leakage. In addition, the CM permeability of ORSS-27055 was also increased by this combination of actives.

Conclusions

These findings provide evidence that isolated α-mangostin alone has not only some activity but also shows the synergistic activity with oxacillin against ORSS-27055. The chromone and isoprenyl structures could play a significant role in its action. This synergistic activity may involve three mechanisms of action. Firstly, potential effects of cytoplasmic membrane disruption and increases permeability. Secondly, inhibit β-lactamase activity. Finally, also damage to the peptidoglycan structure. We proposes the potential to develop a novel adjunct phytopharmaceutical to oxacillin for the treatment of ORSS. Future studies require clinical trials to establish if the synergy reported can be translated to animals and humans.

Phenotypic detection of AmpC β-lactamases, extended-spectrum β-lactamases and metallo-β-lactamases in Enterobacteriaceae using a resazurin microtitre assay with inhibitor-based methods

Dissemination of antibiotic resistance in Enterobacteriaceae mediated by AmpC β-lactamase, extended-spectrum β-lactamase (ESBL) and metallo-β-lactamase (MBL) is clinically significant. A simple and relatively quick method for the detection of these resistance phenotypes would greatly improve chemotherapeutic recommendation. This technology would provide valuable input in our surveillance of resistance on a global stage, particularly if the methodology could be applicable to resource-poor settings. A resazurin microtitre plate (RMP) assay incorporating cloxacillin, clavulanic acid and EDTA for the rapid phenotypic identification of AmpC, ESBL and MBL and the co-existence of β-lactamases has been developed. A total of 47 molecularly characterized Enterobacteriaceae clinical isolates producing AmpCs, ESBLs, co-producers of ESBL and AmpC, MBLs and co-producers of ESBL and MBL were phenotypically examined using the RMP assay. The ceftazidime- and cefotaxime-based RMP assays successfully detected all 16 AmpC, 14 ESBL and 9 MBL producers, 6 ESBL-AmpC co-producers and 2 ESBL-MBL co-producers without false-positive results. The ceftazidime-based assay was more reliable in detecting AmpC alone, while the cefotaxime-based assay performed better in identifying co-producers of ESBL and AmpC. There was no difference in the detection of ESBL and MBL producers. The findings of the present study suggest that use of the RMP assay with particular β-lactamase inhibitors explicitly detects three different β-lactamases, as well as co-existence of β-lactamases, within 6 h of initial isolation of the pathogen. This assay is applicable to carry out in any laboratory, is cost-effective and is easy to interpret. It could be implemented in screening patients and controlling infection and for surveillance purposes.

Trichomonas vaginalis: Clinical relevance, pathogenicity and diagnosis

Trichomonas vaginalis is the etiological agent of trichomoniasis, the most prevalent non-viral sexually transmitted disease worldwide. Trichomoniasis is a widespread, global health concern and occurring at an increasing rate. Infections of the female genital tract can cause a range of symptoms, including vaginitis and cervicitis, while infections in males are generally asymptomatic. The relatively mild symptoms, and lack of evidence for any serious sequelae, have historically led to this disease being under diagnosed, and under researched. However, growing evidence that T. vaginalis infection is associated with other disease states with high morbidity in both men and women has increased the efforts to diagnose and treat patients harboring this parasite. The pathology of trichomoniasis results from damage to the host epithelia, caused by a variety of processes during infection and recent work has highlighted the complex interactions between the parasite and host, commensal microbiome and accompanying symbionts. The commercial release of a number of nucleic acid amplification tests (NAATs) has added to the available diagnostic options. Immunoassay based Point of Care testing is currently available, and a recent initial evaluation of a NAAT Point of Care system has given promising results, which would enable testing and treatment in a single visit.

Conditions for enhancing the encoding of an elementary motor memory by rTMS

OBJECTIVE

Motor learning results in changes of movement representation in primary motor cortex (M1) a process involving long-term potentiation (LTP). Pairing motor training with repetitive transcranial magnetic stimulation (rTMS) of M1 enhances the formation of a motor memory. Here we determined the effect of pairing M1 stimulation and the execution of training movements at different times and frequencies on the formation of a motor memory.

METHODS

Formation of a motor memory was defined as increases in motor evoked potentials (MEP) of the training agonist (extensor carpi ulnaris muscle, ECU) and increases in peak acceleration of the trained movements that last more than 60min. Training consisted of auditory-paced ballistic wrist extension movements (30min, 0.5Hz) paired with 0.1, 0.25 or 0.5Hz subthreshold rTMS. The rTMS pulse was applied at either the onset, 100ms prior to or 300ms after the onset of training movement related increases in electromyographic (EMG) activity of ECU. This was compared to a Sham condition.

RESULTS

Only 0.1Hz rTMS applied at the onset of the training related increase in ECU-EMG activity resulted in increases in MEP amplitudes and peak acceleration when compared to the Sham.

CONCLUSIONS

The formation of motor memory is enhanced above the naïve level by co-administration of low frequency rTMS at the time of execution of training movements.

SIGNIFICANCE

These results indicate the importance of time and frequency of rTMS in these settings and should be considered in the design of rehabilitation treatment strategies using rTMS.

A new approach to studying ion uptake by actinomycetes

A streptomycete that had the ability to avidly sequester iron via siderophores was previously isolated from environmental soil samples. The chelating agent expressed by this organism is confirmed by HPLC as desferrioxamine E. Although the traditional chromo azuerol sulphate (CAS) assay for detection of siderophores is based upon the chelation of iron we were interested to examine the relationship of these iron-capturing molecules with other ions. Consequently, a new approach was employed that enabled the assessment of the affinity of the siderophore moieties for other ions by adapting the CAS assay. The present study reveals that the isolate produced a siderophore that was capable of sequestering a range of ions including Mn, Co, Cd, Ni, Al, Li, Cu, Zn and Mg. On the basis of the assay described it would appear that the organism sequesters copper more readily than iron. This raises an age-old debate surrounding the replacement of copper as a fundamentally essential element with iron as a consequence of the evolution of the di-oxygen environment.

A new approach to isolating siderophore-producing actinobacteria

AIMS

This study was conducted to investigate the application of 2,2'-dipyridyl as a new approach to isolating siderophore-producing actinobacteria.

METHODS AND RESULTS

Isolation of actinobacteria from soil was conducted by a soil dilution plate technique using starch-casein agar. Iron starvation was fostered by the incorporation of the iron chelator 2,2'-dipyridyl in the isolation medium. Pretreatment of the samples at an elevated temperature (40°C) ensured that the majority of nonsporulating bacteria were excluded. The survivors of this treatment were largely actinobacteria. Of the viable cultures grown in the presence of 2,2'-dipyridyl, more than 78-88% (average of three separate studies) were reported to produce siderophore-like compounds compared to 13-18% (average of three separate studies) when grown on the basic media in the absence of the chelating agent. The most prolific producers as assessed by the chrome azurol sulphate (CAS) assay were further characterized and found to belong to the genus Streptomyces.

CONCLUSIONS

Selective pressure using 2,2'-dipyridyl as an iron-chelating agent in starch-casein media increased the isolation of siderophore-producing actinobacteria compared to the unamended medium.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study described represents a new approach to the isolation of siderophore-producing actinobacteria using a novel procedure that places a selection on cell population based upon the incorporation of a chelating agent in the medium.

Diagnosis of Clostridium difficile-associated disease: examination of multiple algorithms using toxin EIA, glutamate dehydrogenase EIA and loop-mediated isothermal amplification

The laboratory diagnosis of Clostridium difficile infection (CDI) needs to be accurate and timely to ensure optimal patient management, infection control and reliable surveillance. Three methods are evaluated using 810 consecutive stool samples against toxigenic culture: CDT TOX A/B Premier enzyme immunoassay (EIA) kit (Meridian Bioscience, Europe), Premier EIA for C. difficile glutamate dehydrogenase (GDH) (Meridian Bioscience, Europe) and the Illumigene kit (Meridian Bioscience, Europe), both individually and within combined testing algorithms. The study revealed that the CDT TOX A/B Premier EIA gave rise to false-positive and false-negative results and demonstrated poor sensitivity (56.47%), compared to Premier EIA for C. difficile GDH (97.65%), suggesting this GDH EIA can be a useful negative screening method. Results for the Illumigene assay alone showed sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of 91.57%, 98.07%, 99.03% and 84.44%, respectively. A two-stage algorithm using Premier EIA for C. difficile GDH/Illumigene assay yielded superior results compared with other testing algorithms (91.57%, 98.07%, 99.03% and 84.44%, respectively), mirroring the Illumigene performance. However, Illumigene is approximately half the cost of current polymerase chain reaction (PCR) methods, has a rapid turnaround time and requires no specialised skill base, making it an attractive alternative to assays such as the Xpert C. difficile assay (Cepheid, Sunnyvale, CA). A three-stage algorithm offered no improvement and would hamper workflow.

P4-12-14: Pilot Study Utilizing Fluorine-18 Fluorodeoxyglucose (F-18 FDG) Positron Emission Tomography–Computed Tomography Scan (PET-CT Scan) To Investigate Brain Metabolic Changes during Treatment in Women with Breast Cancer

BACKGROUND: Approximately 25% of the patients undergoing chemotherapy develop cognitive changes. Similarly, significant neurocognitive changes in verbal memory and executive functioning have been reported in patients undergoing endocrine therapy. Though extensively studied, specific changes in the brain associated with cognitive dysfunction are still not clear. We performed an IRB-approved retrospective pilot study utilizing brain images from standard PET-CT scans in patients being treated for breast cancer. Comparison was made between patients initial and follow-up scans to look for metabolic changes.

MATERIALS AND METHODS: Thirty nine patients with a diagnosis of breast cancer were identified from radiology database of West Virginia University Hospitals, who underwent at least two PET-CT scans during their treatment for breast cancer from 2004–2009. Patients with brain metastasis were excluded. NeuroMIM® software analysis program was used to compare a comprehensive database of physiologic brain anatomy and metabolism with F-18 FDG perfusion brain images from the patients. Comparison was made in sixty-three defined brain regions. For each patient, two scans at approximately twelve month intervals were analyzed. The data sets from initial scans were compared with the follow up.

RESULTS: A total of 37 patients received cytotoxic chemotherapy, 2 patients received only endocrine therapy. Data analysis using the signed-rank test shows that the collective Z-score values change between the initial and follow up scans. When data analysis is applied to the individual brain regions, the Lingual Gyrus (p=0.012) and the Angular Gyrus (p=0.056)show statistically significant and near significant decreases in brain metabolism respectively. These regions are attributed with language, mathematics and cognition. Several additional regions such as the fusiform gyrus and the primary visual cortex show p-values between 0.05 and 0.10, which indicate “trending”. These regions may demonstrate statistically significant decrease in metabolism if the sample size is increased.

DISCUSSION: The Lingual and the Angular Gyrus show a statistically significant and near significant decrease in glucose metabolism respectively, in patients receiving treatment for breast cancer. Limitations of this study include lack of baseline brain imaging and its clinical correlation with cognitive function. Based upon these preliminary findings prospective studies are being planned.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-12-14.

Abstract PD09-03: Disease Outcomes in Primary Breast Cancer Are Associated with Obesity, Lymph Node Status and Angiolymphatic Invasion

Background: Obesity is associated with higher rates of breast cancer and poorer survival. Our previous work has shown that lymph node metastases are more frequently associated with advanced disease in obese patients. We sought to investigate the association of obesity with angiolymphatic invasion on disease outcomes in patients with invasive breast cancer. Methods: This retrospective study involved 627 predominately white women with invasive breast cancer. Hospital tumor registry, charts, and pathology records provided demographics and tumor biologic features. Body mass index (BMI) values were categorized according to WHO criteria: normal or underweight (lean), &lt; 25.0 kg/m2; overweight, 25.0 to 29.9 kg/m2; obese, 30.0 kg/m2 or higher. Univariate and multivariate analyses were conducted between BMI and clinical outcomes, controlling for menopausal status. Recurrence-free survival and overall survival were calculated and a log-rank test was used to determine significance between groups.

Results: In our study cohort, 175 (27.9%) were normal weight, 211 (33.7%) overweight and 241 (38.4%) were considered obese. Greater lymph node involvement and angiolymphatic invasion (P = 0.04) were present with obesity. Triple-negative tumors were more common in those patients classified as overweight and obese (43%) compared to normal weight individuals (20%). Factors associated with BMI were tumor size and lymph node status. In postmenopausal women, obesity was associated with an increased risk of lymph node metastases (OR 1.81, 95% CI 1.14-2.91; P = 0.010) and angiolymphatic invasion (OR 2.09, 95% CI 1.01-4.72; P = 0.049) when compared with normal weight individuals. The probability of developing a relapse within 10 years was higher among women with BMI ≥30.0 with positive lymph nodes and the presence of angiolymphatic invasion.

Conclusions: In obese women with breast cancers, higher rates of lymph node involvement and angiolymphatic invasion may explain poorer outcomes. These findings further support the relationship between obesity and the factors that are elaborated by adipocytes as instrumental in promoting a more aggressive growth and progression of breast cancer.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD09-03.

Predominance of Brain and Lung Metastases in Triple-Negative Breast Cancer Patients

Background: Patients with triple-negative breast cancer have an increased likelihood of recurrence compared to other types of breast cancer, however, little is known about their pattern of metastatic spread. Our object was to evaluate the metastatic patterns of women diagnosed with triple-negative breast cancer compared to other subtypes. Methods: We studied a cohort of 572 white patients diagnosed with invasive breast cancer at West Virginia University Hospital between 1999 and 2004. Hospital registry, charts, and pathology records provided clinical data including tumor receptor status and biopsy-proven metastatic spread to bone, brain, liver and lung. Breast cancers that were negative for estrogen, progesterone, and HER2neu, otherwise known as triple-negative were compared with HER2neu-postive and HER2neu-negative (endocrine receptor positive) disease. Body mass index was calculated and a value of ≥30 considered indicative of obesity. Specimens of primary carcinoma were available for analysis of Ki67 mitotic index and expression of p53. Results: 134/572 (23.4%) had triple-negative breast cancer, while the frequencies were 108/572 (18.9%) and 330/572 (57.7%) in HER2neu-positive and HER2neu-negative (endocrine receptor positive) groups. Women with triple-negative disease were more likely to have brain-metastasizing breast cancer; 10.5% versus 4.6% for HER2neu-positive and 3.3% for HER2neu-negative (P&lt;0.05). They were also more likely to have metastasis to the lung; 10.5% versus 2.8% for HER2neu-positive and 7.0% for HER2neu-negative (P&lt;0.05). Triple-negative breast cancer patients who developed brain and lung metastases were younger &lt;50 years and significantly more obese (P=0.0236). High Ki67 labeling index and p53 expression were associated with more advanced disease indicating an aggressive phenotype for this group.Patterns of metastasis in breast cancer subtypesSite of metastasisTriple-negativeHER2-positiveHER2-negativeP valueBone20/134 (14.9)7/108 (6.5)38/330 (11.5)0.1037Brain14/134 (10.5)5/108 (4.6)11/330 (3.3)0.0136*Liver11/134 (8.2)4/108 (3.7)22/330 (6.7)0.3261Lung14/134 (10.5)3/108 (2.8)23/330 (6.9)0.0507*Other5/134 (3.7)3/108 (2.8)3/330 (0.91)0.1093 Conclusion: The excess risk of brain and lung metastasis in women with triple-negative breast cancers versus other subtypes needs further validation. The unique biology of triple-negative tumors may explain this pattern of metastatic spread.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6159.

Significance of MTHFR gene mutation with normal homocysteine level in vascular events

e20520

Background: Hyperhomocysteinemia, due to a combination of genetic and environmental factors, is considered to be a risk factor for vascular disease. Two common variations of the MTHFR gene (C677T and A1298C) result in amino acid substitutions and enhanced thermolability of the enzyme. Individuals with MTHFR gene mutations appear to have raised plasma level of homocysteine which may lead to increased risk of vascular events. However, significance of MTHFR gene mutations with normal homocysteine levels is unknown. Objective: To assess the relation of MTHFR gene mutations with normal homocysteine level and risk of Vascular events (deep venous thrombosis (DVT), pulmonary embolism (PE), Ischemic Heart disease (IHD), cerebrovascular accidents (CVA),recurrent fetal loss). Methods: We reviewed the records of 90 patients referred to our benign hematology clinic for thrombophilia evaluation between 2006 and 2008. All available medical history for risk factors and laboratory test results, obtained from first vascular event through time of consultation, including genetic testing, were reviewed. Anti-cardiolipin antibody, MTHFR genotyping and Protein C and Protein S assays were performed at Warde Medical Laboratory, Ann Arbor, MI. Results: 61 patients with documented vascular events were tested for MTHFR gene mutations. Forty one of these patients also had homocysteine levels available. Thirty-eight of these 41 (92 %) patients had an MTHFR gene mutation with normal homocysteine levels. Eighteen (47%) of these 38 patients had only an MTHFR gene mutation with normal homocysteine level and no other congenital or acquired risk factors for vascular events identified. Conclusions: In our clinic population, many patients with documented vascular events had MTHFR gene polymorphisms with normal homocysteine levels with no other thrombophilia risk factors identified, raising the question of whether MTHFR gene polymorphisms alone, without hyperhomocysteinemia, may somehow contribute to thrombophilia.

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No significant financial relationships to disclose.

Impact of FDG-PET scan on follow-up care in nonmetastatic breast cancer

e11611

Background: Fluorine-18-FDG positron emission tomography (FDG-PET) role in the follow up care of non-metastatic breast cancer is not defined. Methods: We retrospectively analyzed 177 patients with stage I-III breast cancer between November 2004 and June 2006. IRB approval was obtained for this study. Patients were divided into two groups. Group A consisted of patients who had one or more FDG-PET scans as part of their clinical follow up (N=68), and Group B consisted of patients who did not (N=109). Clinical, radiological and pathology data were obtained from patients’ records. Results: Median follow-up is 35 months. Mean age 53 years for group A and 57 years for group B. Group A patients were more likely to have had higher stages (29% stage I, 53% stage II, and 18% stage III) compared with group B (64 % stage I, 31% stage II and 4% stage III). The two groups did not differ significantly in ER+ status (69% vs. 78% p=0.21), or Her2neu status (19% vs. 17%; p=0.6). Group A patients had more clinic visits (18 vs. 11; p=0.009), their tumor marker was checked more often (13 vs. 9 times; p=0.0001), had more radiological studies (10 studies vs. 5; p=0.0001), and had more biopsies (0.88 vs. 0.48 biopsy per patient; p=0.05). These differences were significant even after controlling for stage and chemotherapy. 9/68 patients in group A had tumor recurrence compared to 1/109 in group B (p=0.0003). PET scan indications were as follows: 29 (43%) for asymptomatic follow up evaluation [2 recurred]; 18 (26%) concerning symptoms [0 recurred]; 10 (15%) elevated tumor marker [2 recurred]; 7 (10%) other abnormal imaging studies [1 recurred]; 4 (6%) metastatic workup. Conclusions: While FDG-PET might aid in detecting recurrence in some patients with non-metastatic breast cancer, its use was associated with more clinic visits, blood tests, biopsies, and radiological tests.

No significant financial relationships to disclose.

Triple-negative breast cancer and obesity in a rural Appalachian population

Abstract #6099

Background: Our objective was to determine the clinico-pathological features of triple-negative (estrogen, progesterone and HER-2 receptor negative) breast cancer and their relationship to obesity in women drawn from a population with one of the highest obesity rates in the United States.&#x2028; Methods: This retrospective study involved 620 white patients with invasive breast cancer in West Virginia. Hospital tumor registry, charts, and pathology records provided age at diagnosis, tumor histologic type, size, and nodal status, and receptor status. Body mass index (BMI) was calculated and a value of ≥30 considered indicative of obesity.&#x2028; Results: Triple-negative tumors occurred in 117 (18.9%) of the 620 patients, most often in association with invasive ductal carcinomas. Patients with triple-negative tumors were younger than those with other receptor types, 44.5% and 26.7%, respectively, being diagnosed before age 50 years (P = 0.0004). The triple-negative tumors were larger (P = 0.0003), most notably in the younger women, but small tumors (&lt;2.0 cm) were more often accompanied by lymph node metastases. Obesity was present in 49.6% of those with triple-negative tumors, but only 35.8% of those with non-triple-negative tumors (P = 0.0098). Lymph node metastases were more frequently associated with T2 tumors in obese patients (P = 0.032) regardless of their receptor status.&#x2028; Conclusions: Triple-negative breast cancers within a white, socioeconomically-deprived, population occurred in younger women, with later stage at diagnosis, and in association with obesity. The elevated adipokine production which is present in obesity may exert tumor proliferative and angiogenic effects that contribute to an aggressive phenotype.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6099.

Evaluation of the potential of applying composting/bioremediation techniques to wastes generated within the construction industry

The objective of the present study was to evaluate the viability of reducing landfill requirements to satisfy EC Landfill Directive requirements by applying composting/bioremediation techniques to the construction and demolition (C&D) industry waste stream at laboratory scale. The experimental study was carried out in nine test rigs to examine different wood mixtures; untreated timber, creosote treated timber and chromated copper arsenate (CCA) treated timber. Several experimental variables affecting the process were characterised and optimised. These include the best nitrogen additive and optimum moisture content required for composting. Poultry manure was found to be the best nitrogen additive. The optimum moisture content was decreased after the addition of poultry manure. The composting/bioremediation process was evaluated through monitoring the microbial activity, carbon dioxide emissions and toxicity examination of the composted product. A typical temperature profile suggested that untreated and CCA treated mix could be classified as hot composting whereas creosote treated mix could be classified as cold composting. The paper reports on the results obtained during this investigation.

Application of Toxocara canis excretory-secretory antigens and IgG subclass antibodies (IgG1-4) in serodiagnostic assays of human toxocariasis

A major problem in the serodiagnosis of human toxocariasis in tropical countries is cross-reaction with antibodies to other helminthic diseases and a lack of sensitivity. The majority of tests currently available use total IgG and, in this study, the use of peroxidase-conjugated anti-human IgG subclass antibodies (IgG1-4) was compared with total IgG for the diagnosis of human toxocariasis by using Toxocara excretory-secretory (TES) antigens in an enzyme-linked immunosorbent assay (ELISA) format. All four IgG subclass antibodies gave approximately 10-fold increases in optical density (OD) values for 50 toxocariasis patients compared to 29 healthy normals; this was significantly greater than the approximate doubling of OD values seen in the total IgG-ELISA format. IgG2 gave by far the greatest sensitivity (values: IgG, 50%; IgG1, 60%; IgG2, 98%; IgG3, 78%; IgG4, 64%). Significant cross-reactivity using all IgG subclasses in the TES ELISA was seen with 141 serum samples from patients with 10 other helminthic infections. However, IgG3 gave the best specificity (values: IgG, 73%; IgG1, 76%; IgG2, 71%; IgG3, 81%; IgG4, 71%). Thus, of the IgG subclass antibodies, IgG2 appeared best and employing this subclass can improve the serodiagnosis of human toxocariasis since it recognises carbohydrate epitopes of TES antigens.

Composting and bioremediation process evaluation of wood waste materials generated from the construction and demolition industry

The suitability of using bioremediation and composting techniques for diverting construction and demolition (C&D) waste from landfill has been validated in this study. Different timber products from C&D waste have been composted using various composting approaches. The present work demonstrates the quality of compost produced as a result of composting of mixed board product wood waste, which is frequently obtained from the construction and demolition industry. Three compost mixes were prepared by mixing shredded chip board, medium density fibre, hardboard and melamine. Poultry manure, Eco-Bio mixture and green waste were used as nutrient supplements. The results revealed that compost produced from mixtures of poultry manure and green waste used as nutrient supplements improved the performance in plant growth trials (phytotoxicity tests). Results obtained from the experimental study clearly indicate that the composts produced comply with the criterion suggested in BSI PAS 100 (A specification for compost materials) for use in different applications. Composting can also be demonstrated to be a very practical approach to material management including transport reduction to and from the site. The economic suitability of the process will be improved with the increase in landfill tax. In the current regulatory scenario, it is recommended that these materials should be composted at a centralised facility.

The reliability of the Vernon and Mior neck disability index, and its validity compared with the short form-36 health survey questionnaire

Prospective single cohort study. To evaluate the NDI by comparison with the SF36 health Survey Questionnaire. The NDI is a simple ten-item questionnaire used to assess patients with neck pain. The SF36 measures functional ability, well being and the overall health of patients. It is used as a gold standard in health economics to assess the health utility, gain and economic impact of medical interventions. One hundred and sixty patients with neck pain attending the spinal clinic completed self-assessment questionnaires. A second questionnaire was completed in 34 patients after a period of 1-2 weeks. The internal consistency of the NDI and SF36 was calculated using Cronbach's alpha. The test-retest reliability was assessed using the Bland and Altman method. The concurrent validity of the NDI with respect to the SF-36 was assessed using Pearson correlations. Both questionnaires showed robust internal consistency: Cronbach's alpha for the NDI scale was acceptable (0.864, 95% confidence limits 0.825-0.894) though slightly smaller than that of the SF36. The correlations between each item of the NDI scores and the total NDI score ranged from 0.447 to 0.659, (all with P < 0.001). The test-retest reliability of the NDI was high (intra-class correlation 0.93, 95% confidence limits 0.86-0.97) and comparable with the best values found for SF36. The correlations between NDI and SF36 domains ranged from -0.45 to -0.74 (all with P < 0.001). We have shown that the NDI has good reliability and validity and that it compares well with the SF36 in the spinal surgery out patient setting.