Specific Instantaneous Detection of Klebsiella pneumoniae for UTI Diagnosis with a Plasmonic Gold Nanoparticle Conjugated Aptasensor

Urinary tract infection (UTI), which can be caused by various pathogens, if not detected at an early stage can be fatal. It is essential to identify the specific pathogen responsible for UTI for appropriate treatment. This study describes a generic approach to the fabrication of a prototype for the noninvasive detection of a specific pathogen using a tailor-made plasmonic aptamer-gold nanoparticle (AuNP) assay. The assay is advantageous because the adsorbed specific aptamers passivate the nanoparticle surfaces and reduce and/or eliminate false-positive responses to nontarget analytes. Based on the localized surface plasmon resonance (LSPR) phenomena of AuNP, a point-of-care aptasensor was designed that shows specific changes in the absorbance in the visible spectra in the presence of a target pathogen for robust and fast screening of UTI samples. In this study, we demonstrate the specific detection of Klebsiella pneumoniae bacteria with LoD as low as 3.4 × 103 CFU/mL.

Point-of-Care Biosensing of Urinary Tract Infections Employing Optoplasmonic Surfaces Embedded with Metal Nanotwins

We report the synthesis of gold nanotwins (Au NTs) on a solid and transparent glass substrate which in turn has been employed for the selective optoplasmonic detection of Escherichia coli (EC) bacteria in human urine for the point-of-care diagnosis of urinary tract infections (UTIs). As compared to the single nanoparticle systems (Au NPs), the Au NTs show an enriched localized surface plasmon resonance (LSPR) due to the enhancement of the electric field under electromagnetic irradiation, e.g., photon, which helps in improving the limits of detection. For this purpose, initially a simple glass surface has been coated with Au NPs, with the help of the linker 3-aminopropyl-triethoxysilane - APTES. The surface has been linked further with another Au NP with the help of the 1,10-alkane-dithiol linker with two thiol ends, which eventually leads to the development of the optoplasmonic surface with Au NTs and an enhanced LSPR response. Subsequently, the EC specific aptamer has been chemically immobilized on the surface of Au NTs with the blocking of free sites via bovine serum albumin (BSA). Remarkably, Raman spectroscopy unfolds a 7-fold increase in the peak intensities with the Au NTs on the glass surface as compared to the surface coated with isolated Au NPs. The enhancement in the LSPR response of glass substrates coated with Au NTs and the EC specific aptamer has been further utilized for the selective and sensitive detection of UTIs. The results have been verified with the help of UV-visible spectroscopy to establish the utility of the proposed sensing methodology. An extensive interference study with other bacterial species unveils the selectivity and specificity of the proposed optoplasmonic sensors toward EC with a detection range of 5 × 10³ to 10⁷ CFU/mL. Intuitively, the method is more versatile in a sense that the sensor can be made specific to any other pathogens by simply changing the design of the aptamer. Finally, a low-cost, portable, and point-of-care optoplasmonic transduction setup is designed with a laser light illumination source, a sample holder, and a sensitive photodetector for the detection of UTIs in human urine.

Do women's perspectives of quality of care during childbirth match with those of providers? A qualitative study in Uttar Pradesh, India

Background: Persistently high maternal mortality levels are a concern in developing countries. In India, monetary incentive schemes have increased institutional delivery rates appreciably, but have not been equally successful in reducing maternal mortality. Maternal outcomes are affected by quality of obstetric care and socio-cultural norms. In this light there is need to examine the quality of care provided to women delivering in institutions.

Objective: This study aimed to examine pregnant women’s expectations of high-quality care in public health facilities in Uttar Pradesh, India, and to contrast this with provider’s perceptions of the same, as well as the barriers that limit their ability to provide high-quality care.

Methods: A qualitative descriptive analysis was conducted on data from two studies – focus group discussions with rural women in their last trimester of pregnancy (conducted in 2014) to understand women’s experience and satisfaction with maternal care services, and in-depth interviews with care providers (conducted in 2016–17) to understand provision of person-centred care. Provider perspectives were matched with themes of women’s perspectives on quality of childbirth care in facilities.

Results: Major themes of care prioritised by women included availability of doctors at the facility; availability of medicines; food; ambulance services; maintenance of cleanliness and hygiene; privacy; good and safe delivery with no complications; client-provider interaction; financial cost of care. Many women also voiced no expectation of care, indicating disillusionment from the existing system. Providers concurred with women on all themes of care except availability of doctors, as they felt that trained nurses were proficient in conducting deliveries.

Conclusions: This study shows that women have clear expectations of quality care from facilities where they go to deliver. Understanding their expectations and matching them with providers’ perspectives of care is critical for efforts to improve the quality of care and thereby impact maternal outcomes.

Epidemiological study of ocular trauma in an urban slum population in Delhi, India

Purpose:

To study the epidemiology and clinical profile of victims of ocular trauma in an urban slum population.

Materials and Methods:

This cross-sectional study, conducted on 500 families each in three randomly selected urban slums in Delhi, collected demographic data for all members of these families, and clinical data for all those who suffered ocular trauma at any time, that required medical attention. Data was managed on SPSS 11.0.

Results:

Of 6704 participants interviewed, 163 episodes of ocular trauma were reported by 158 participants (prevalence = 2.4%, confidence interval = 2.0 to 2.7) Mean age at trauma was 24.2 years. The association between the age of participants and the history of ocular trauma was significant (P < 0.001), when adjusted for sex, education and occupation. Males were significantly more affected. Blunt trauma was the commonest mode of injury (41.7%). Blindness resulted in 11.4% of injured eyes ( P = 0.028). Of 6704 participants, 1567 (23.4%) were illiterate, and no association was seen between education status and trauma, when adjusted for sex and age at injury. A significant association was noted between ocular trauma and workplace (Chi-square = 43.80, P < 0.001), and between blindness and place (Chi-square = 9.98, P = 0.041) and source (Chi-square = 10.88, P = 0.028) of ocular trauma. No association was found between visual outcome and the time interval between trauma and first consultation (Chi-square = 0.50, P = 0.78), between receiving treatment and the best corrected visual acuity (Chi-square = 0.81, P = 0.81), and between the person consulted and blinding ocular trauma (Chi-square = 1.88, P = 0.170).

Conclusion:

A significant burden of ocular trauma in the community requires that its prevention and early management be a public health priority.

A comparison of the circadian rhythm of intraocular pressure in primary phronic angle closure glaucoma, primary open angle glaucoma and normal eyes

PURPOSE

To evaluate the circadian rhythm of intraocular pressure (IOP) in primary chronic angle closure glaucoma (PCACG), primary open angle glaucoma (POAG), and normal eyes.

METHODS

Cross-sectional study of newly diagnosed patients of POAG (60 eyes), PCACG following laser iridotomy (75 eyes), and age and sex matched normal controls (75 eyes). All subjects underwent applanation tonometry at 7 a.m., 10 a.m., 1 p.m., 4 p.m., 7 p.m., and 10 p.m. by a masked observer. Circadian rhythms were classified based upon the timing and presence of peak pressure.

RESULTS

Age and gender in all three groups were comparable. Diurnal IOP fluctuations were significantly higher in PCACG (7.69+3.03 mmHg) and POAG (8.31+2.58 mmHg) groups compared to normal controls (4.83 + 2.46 mmHg). PCACG eyes and controls had similarly timed circadian rhythms, with PCACG eyes having a consistently higher IOP. At 7 and 10 a.m., IOP peaked more often in POAG eyes compared to PCACG eyes. A plateau type of circadian rhythm was most common in normal eyes. The timing of peak IOP could be significantly correlated with the type of primary glaucoma examined.

CONCLUSION

Afternoon peaks were more common in postiridotomy PCACG eyes, similar to the rhythm in normal eyes. Morning peaks were more frequent in POAG eyes. Diurnal fluctuation > 6 mmHg, associated with an IOP of 21 mmHg or more was never seen in a normal eye.

Comparative study of vitrectomy for dropped nucleus with and without the use of perfluorocarbon liquid. Clinical, electrophysiological and visual field outcomes

PURPOSE

To compare pars plana vitrectomy for dropped nucleus with and without perfluorocarbon liquid.

METHODS

24 eyes with dropped nucleus were randomized to undergo PPV with perfluorodecalin, (study, n=12) and without it (control, n=12). Visual acuity, IOP, visual evoked response and electroretinography were noted at study entry and up to 3 months after PPV. Humphrey perimetry was done at 3 months.

RESULTS

Final visual acuity was >20/60 in 75% of study eyes and 41.6% of controls. The two groups were statistically comparable with regard to the above parameters before PPV and during follow-up. The timing of vitrectomy did not significantly influence the final visual acuity. A higher rate of complications was seen in the control group.

CONCLUSIONS

Perfluorodecalin facilitated the procedure and possibly minimized complications, and was found to be safe for intraoperative use in terms of recovery of visual acuity, stable ERG and VER, and normal visual fields.