Investigating the Role of Antibiotics on Induction, Inhibition and Eradication of Biofilms of Poultry Associated Escherichia coli Isolated from Retail Chicken Meat.

Background: Widespread use of antibiotics as growth promoters and prophylactic agents has dramatic consequences for the development of antibiotic resistance. In this study, we investigated effects of selected antibiotics on bacterial biofilms and performed extensive antibiotic and VF profiling of poultry-meat associated E. coli strains. Methods: Antibiotic susceptibility was performed by a disc diffusion method, followed by molecular screening of resistance and virulence determinants. Further biofilm formation assays, MIC-p, MIC-b, MBIC and MBEC, were performed using standard tissue culture plate method. Results: In total, 83 (75%) samples were confirmed as E. coli from poultry sources, 26 different antibiotics were tested, and maximum numbers of the isolates were resistant to lincomycin (100%), while the least resistance was seen against cefotaxime (1%) and polymyxin B (1%). Overall, 48% of the isolates were ESBL producers and 40% showed carbapenemase activity; important virulence genes were detected in following percentages: fimH32 (39%), papC21 (25%), iutA34 (41%), kpsMT-II23 (28%), papEF9 (11%), papGII22 (27%) and fyuA13 (16%). Colistin showed remarkable anti-biofilm activity, while at sub-MIC levels, gentamicin, ceftriaxone and enrofloxin significantly (p < 0.01) inhibited the biofilms. A strong induction of bacterial biofilm, after exposure to sub-minimal levels of colistin clearly indicates risk of bacterial overgrowth in a farm environment, while use of colistin aggravates the risk of emergence of colistin resistant Enterobacteriaceae, a highly undesirable public health scenario.

Diagnostic Accuracy of Serum Procalcitonin (PCT) as an Early Biomarker of Neonatal Sepsis using Blood Culture as Gold Standard.

OBJECTIVE: To ascertain the diagnostic accuracy of serum PCT as an early biomarker of neonatal sepsis using blood culture as gold standard, so that the condition could be diagnosed and managed early to prevent and reduce morbidity and mortality in neonates.  Study Design: Cross-sectional study. PLACE AND DURATION OF STUDY: Dr. Ziauddin University Hospital, Karachi, from March 2019 to December 2019. METHODOLOGY: A total of 171 neonates, 1-29 days of age, presented with clinical diagnosis of neonatal sepsis, were included in this study. Patients' data regarding age, gender, birth weight, prematurity and premature rupture of membranes (PROM) were collected. Blood cultures were performed in Microbiology Department; and Serum PCT was analyzed on Electrochemiluminescence Immunnoassay Analyzer (Cobas e601). Diagnostic accuracy, including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of PCT were calculated with contingency tables using blood culture findings as gold standard. RESULTS: Out of 171 clinically diagnosed cases of neonatal sepsis, 86 (50.3%) were confirmed as having neonatal sepsis (blood culture positive). There was a significant difference in serum PCT levels in both the groups. The sensitivity of PCT was 97.7%; specificity 70.6%; PPV 77.1; NPV 96.8%; likelihood ratio of a positive test (LR+ve) 3.32; likelihood ratio of a negative test (LR -ve) 0.03, and cumulative diagnostic accuracy of PCT 84.2%. CONCLUSION: PCT is a very useful biomarker for the early diagnosis of neonatal sepsis, showing 84.2% diagnostic accuracy. Thus PCT can help in making early clinical decisions regarding management of patients. Key Words: Diagnostic accuracy, PCT, Neonatal sepsis.

Optically selective and electrochemically active chemosensors for Cu (II) ions based on a skeleton of 2-(benzylideneamino)-4,5,6,7-tetrachloro-3',6'-dihydroxyspiro-[isoindoline-1, 9'-xanthen]-3-one.

A new series of fluorescent chemosensors (7a-7f) based on a core skeleton of 2-(benzylideneamino)-4,5,6,7-tetrachloro-3',6'-dihydroxyspiro-[isoindoline-1,9'-xanthen]-3-one was synthesized and characterized by FT-IR, NMR and mass spectrometric techniques. The sensitivity and selectivity of probes (7a-7f) for Cu2+ ions were investigated by colorimetric, UV-vis absorption, fluorescence emission spectral studies and electrochemical analysis. These optical probes exhibited higher sensitivity and selectivity towards Cu2+ ions in DMSO solution over various other metal cations under consideration. Induced changes were observable by naked-eye. Based on fluorescence titration spectra and Job's-plot, it was found that the complexes formed between probes (7a-7f) and Cu2+ ions were in 1:1 stoichiometric ratio. The detection limit for chemosensors (7a-7f) were calculated to be 3.0834 × 10-7-3.6425 × 10-7 M.

AAV-mediated netrin-1 overexpression increases peri-infarct blood vessel density and improves motor function recovery after experimental stroke.

Apart from its role in axon guidance, netrin-1 is also known to be pro-angiogenic. The aim of this study is to determine whether adeno-associated viral (AAV) mediated overexpression of netrin-1 improves post-stroke neurovascular structure and recovery of function. AAV-Netrin-1 or AAV-LacZ of 1×10(10) genome copies each was injected medial and posterior to ischemic lesion at one hour following reperfusion using the distal middle cerebral artery occlusion (MCAO) method. Quantitative RT-PCR revealed that the expression of netrin-1 transgene began as early as one day and increased dramatically about 3 weeks following vector injection. Western blot analysis and confocal microscopy suggested that both the endogenous and transduced netrin-1 were expressed in the neurons of the peri-infarct cortex after MCAO. AAV-mediated netrin-1 overexpression significantly increased vascular density in the peri-infarct cortex and promoted the migration of immature neurons into the peri-infarct white matter, but it did not significantly reduce infarct size. Netrin-1 overexpression also enhanced post-stroke locomotor activity, improved exploratory behavior, and reduced ischemia-induced motor asymmetry in forelimb usage. However, it had little effect on post-stroke spatial learning and memory. Our results suggest that AAV mediated netrin-1 overexpression improves peri-infarct vascular density and post stroke motor function.

Production of random DNA oligomers for scalable DNA computing.

While remarkably complex networks of connected DNA molecules can form from a relatively small number of distinct oligomer strands, a large computational space created by DNA reactions would ultimately require the use of many distinct DNA strands. The automatic synthesis of this many distinct strands is economically prohibitive. We present here a new approach to producing distinct DNA oligomers based on the polymerase chain reaction (PCR) amplification of a few random template sequences. As an example, we designed a DNA template sequence consisting of a 50-mer random DNA segment flanked by two 20-mer invariant primer sequences. Amplification of a dilute sample containing about 30 different template molecules allows us to obtain around 10(11) copies of these molecules and their complements. We demonstrate the use of these amplicons to implement some of the vector operations that will be required in a DNA implementation of an analog neural network.

A novel haplotype in ABCA1 gene effects plasma HDL-C concentration.

BACKGROUND AND OBJECTIVES: ATP-binding cassette transporter 1 (ABCA1) is a trans-membrane protein responsible for the efflux of cholesterol and phospholipids across the cell membrane, an essential step in the reverse cholesterol transport system. This study investigates the effect of five non-synonymous SNPs of ABCA1 gene on plasma HDL-C levels in Pakistani individuals free of ischemic heart disease and stroke. METHODS: Five non-synonymous SNPs were selected after sequencing ABCA1 gene in patients of Hypoalphalipoproteinemia. The presence of these SNPs was then checked in 200 individuals by using PCR-RFLP. Plasma glucose and lipid fractions were measured in fasting state. Ethical approval was obtained from the Ethical Review Committee, Aga Khan University and informed consent was obtained from all subjects. RESULTS: LL genotype of V825L polymorphism was associated with decreased levels of HDL-C [-0.17 (-0.32 to -0.19); P=0.02] and P774 allele showed a significant increase in HDL-C levels as compared to T774 allele [-0.15 (-0.18 to -0.02); P=0.01]. R219K, A399V and V771M polymorphisms did not show any association with levels of HDL-C, LDL-C, cholesterol and triglycerides. Haplotype analysis between R219K and V825L polymorphisms showed a unique interaction between R219 allele and L825 allele. The RL haplotype was found to be associated with decreased levels of HDL-C [-0.12 (-0.22 to -0.03); P=0.001]. CONCLUSIONS: ABCA1 polymorphisms are associated with varying levels of HDL-C in Pakistani individuals. These results warrant further investigations as ABCA1 polymorphisms may have a major role in the high incidence of cardiovascular disorders in South Asians.