Surface-enhanced Raman spectroscopy (SERS) for monitoring colistin-resistant and susceptible E. coli strains.

The emergence of drug-resistant bacteria is a precarious global health concern. In this study, surface-enhanced Raman spectroscopy (SERS) is used to characterize colistin-resistant and susceptible E. coli strains based on their distinguished SERS spectral features for the development of rapid and cost-effective detection and differentiation methods. For this purpose, three colistin-resistant and three colistin susceptible E. coli strains were analyzed by comparing their SERS spectral signatures. Moreover, multivariate data analysis techniques including Principal component analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA) were used to examine the SERS spectral data of colistin-resistant and susceptible strains. PCA technique was employed for differentiating colistin susceptible and resistant E.coli strains due to alteration in biochemical compositions of the bacterial cell. PLS-DA is employed on SERS spectral data sets for discrimination of these resistant and susceptible E. coli strains with 100% specificity, 100% accuracy, 99.8% sensitivity, and 86% area under receiver operating characteristics (AUROC) curve.

Surface-enhanced Raman spectral investigation of antibacterial activity of zinc 3-chlorobenzoic acid complexes against Gram-positive and Gram-negative bacteria.

BACKGROUND: Raman spectroscopy is an effective tool for determining the antibacterial actitivites of organometallic compounds against different bacterial strains. OBJECTIVES: The purpose of current study is to check the anibacterial activites of ligand (3-chlorobenzoic acid) and its respective zinc complex against gram positive and gram-negative bacterial strains by using surface enhanced Raman spectroscopy (SERS). METHODS: The ligand (3-chlorobenzoic acid) and its respective zinc complex caused different biochemical changes in gram-positive and gram-negative bacterial strains such as lipid contents, DNA/RNA contents, proteins contents, peptidoglycan contents and bacterial spore contents which can be observed with different SERS spectral features. Furthermore, PCA was employed for differentiating the mechanism of action of zinc complexes against gram-positive bacterial strain and gram-negative bacterial strain. RESULTS: Surface enhanced Raman spectroscopy (SERS) has been employed for analyzing the antibiotic activities of 3-chlorobenzoic acid ligands and their respective zinc complexes against Escherichia coli (gram-negative) and Bacillus subtilis (gram-positive) bacterial strains. The bioactivity assay and SERS spectral results clearly show that the complex causes more degradation in both bacterial cells (E. coli and B. subtilis) as compared to ligand. Furthermore, PCA was employed for differentiating the mechanism of action of zinc complexes against gram-positive bacterial strain and gram-negative bacterial strain. CONCLUSION: SERS technique along with chemometric tools have successfully differentiated the antibiotic activities of 3-chlorobenzoic acid ligands and their respective zinc complexes against Escherichia coli (gram-negative) and Bacillus subtilis (gram-positive) bacterial strains.

Surface-enhanced Raman spectroscopy of polymerase chain reaction (PCR) products of Rifampin resistant and susceptible tuberculosis patients.

BACKGROUND: Raman spectroscopy is an effective tool for detecting and discriminating microorganisms that is robust, reliable, and rapid. OBJECTIVES: To develop a polymerase chain reaction technique (PCR) based on Surface Enhanced Raman Spectroscopy (SERS) technique with principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to assess diagnostic capability of SERS for distinguishing between tuberculosis (TB) positive rifampin resistant and tuberculosis (TB) positive rifampin susceptible samples. METHODS: Silver nanoparticles (Ag NPs) were used as SERS substrates and technique was used to distinguish TB positive rifampin (RIF) resistant and TB positive rifampin (RIF) susceptible patients on the basis of characteristic SERS spectral features of their respective PCR products. SERS spectra were acquired from 52 samples of PCR products including 22 samples of TB positive rifampin susceptible, 30 samples of TB positive rifampin resistant and negative control samples. All these samples were collected from individuals of same age. Furthermore, multivariate data analyses techniques such as PCA and PLS-DA were used to assess diagnostic capability of SERS for distinguishing between TB positive rifampin resistant and TB positive rifampin susceptible samples. RESULTS: PCA is found helpful for successful differentiation among these two groups of spectral data sets. Moreover, PLS-DA provides this classification quantitatively by predicting the class of SERS spectral data set with 73% area under curve, 96% sensitivity, 95.6% specificity and 95% accuracy. CONCLUSION: SERS can be employed for the rapid distinguishing between TB positive rifampin resistant and TB positive rifampin susceptible samples.

Sodium arsenate induced genotoxicity, morphometric and morphological changes in mice embryo and protective role of Moringa oleifera extracts.

The present study was carried out to find the comparative ameliorative role of Moringa oleifera leaf and flower extracts against sodium arsenate induced genotoxic, morphometric and morphological changes in mice embryo. Seven to eight week old pregnant females (N=44) with body weight of 20-25g at gestation day zero were divided randomly in groups (A, B, C, D, E, F, G, H, I, J and K). Group A was of control while all others were experimental groups and administered with selected doses of sodium arsenate as toxicant (6mg/kg B.W and 12mg/kg/B.W) and Moringa oleifera leaf and flower extracts as antidote (150mg/kg and 300mg/kg B.W). Significant (p<0.05) amelioration at dose 300mg/kg of Moringa oleifera leaf extract was observed against sodium arsenate induced morphological abnormalities like micromelia, excencephally, cryptothalmia, anopthalmia, laproschisis and morphometric changes like fetus weight, head circumference, crown rump and snout length were observed. Significant protection of DNA was showed in Moringa oleifera leaf extract treated groups (27.50±2.51) as compared to sodium arsenate (66.25±2.75). So concluded that sodium arsenate induced teratogenicity can be decreased using Moringa extract especially of Moringa oleifera leaf extract as it contains bioactive compounds like phenolics.

Surface-enhanced Raman spectroscopy for comparison of serum samples of typhoid and tuberculosis patients of different stages.

BACKGROUND: Surface-enhanced Raman spectroscopy (SERS) is a reliable tool for the identification and differentiation of two different human pathological conditions sharing the same symptomology, typhoid and tuberculosis (TB). OBJECTIVES: To explore the potential of surface-enhanced Raman spectroscopy for differentiation of two different diseases showing the same symptoms and analysis by principal component analysis (PCA) and partial least square discriminate analysis (PLS-DA). METHODS: Serum samples of clinically diagnosed typhoid and tuberculosis infected individuals were analyzed and differentiated by SERS using silver nanoparticles (Ag NPs) as a SERS substrate. For this purpose, the collected serum samples were analyzed under the SERS instrument and unique SERS spectra of typhoid and tuberculosis were compared showing notable spectral differences in protein, lipid and carbohydrates features. Different stages of the diseased class of typhoid (Early acute and late acute stage) and tuberculosis (Pulmonary and extra-pulmonary stage) were compared with each other and with healthy human serum samples, which were significantly separated. Moreover, SERS data was analyzed using multivariate data analysis techniques including principal component analysis (PCA) and partial least square discriminate analysis (PLS-DA) and differences were so prominent to observe. RESULTS: SERS Spectral data of typhoid and tuberculosis showed clear differences and were significantly separated using PCA. SERS spectral data of both stages of typhoid and tuberculosis were separated according to 1st principle component. Moreover, by analyzing data using partial least square discriminate analysis, differentiation of two disease classes were considered more valid with a 100% value of sensitivity, specificity and accuracy. CONCLUSION: SERS can be employed for identification and comparison of two different human pathological conditions sharing same symptomology.

Descemet's Membrane Dehiscence Resulting From Misdirected Viscoelastic During Anterior Chamber Reformation.

We report a case of Descemet's membrane detachment after inadvertent intrastromal injection of hyaluronic acid. Surgical removal was attempted with minimal but slow improvement. Near-complete resolution occurred with subsequent conservative management within 6 weeks.

Sleep-disordered breathing and transcranial Dopplers in sickle cell disease.

OBJECTIVES: To determine the prevalence of sleep-disordered breathing in children with sickle cell disease and whether there is an association of sleep-disordered breathing with high-risk transcranial Doppler ultrasonography (TCD) velocities. Study DESIGN: Cross-sectional. SETTING: Tertiary care academic medical center. PATIENTS: Sixty-four children (aged 2-14 years) selected for eligible genotype (type SS or Sß(0)-thalassemia) and no history of stroke. INTERVENTIONS: Parents completed the Pediatric Sleep Questionnaire. Overnight polysomnography was performed for children with snoring. The TCD was performed or existing results were obtained for all children; for children who underwent transfusion therapy, readings prior to the transfusion were analyzed. Children with abnormal or conditional TCD (flow velocity ≥170 cm/s in any vessel) were considered high risk. MAIN OUTCOME MEASURES: Prevalence of sleep-disordered breathing and TCD velocity and frequency of high-risk TCD in patients with and without sleep-disordered breathing. RESULTS: The prevalence of snoring was 37.5% (95% CI, 26.7%-49.8%), the prevalence of positive polysomnography findings was 23.7% (14.6%-36.1%), and the prevalence of positive Pediatric Sleep Questionnaire scores was 21.9% (13.4%-33.6%). There was no significant difference in TCD velocity or number of patients with high-risk TCD between nonsnorers and children with snoring but negative polysomnography findings and children with snoring and positive polysomnography findings (P = .91 and P = .66, respectively) or between nonsnorers and snorers with a negative Pediatric Sleep Questionnaire score and snorers with a positive Pediatric Sleep Questionnaire score (P = .76 and P = .33, respectively). CONCLUSION: There is a high prevalence of snoring and sleep-disordered breathing among children with sickle cell disease, but our results do not support an association with cerebrovascular risk.