The discovery of antibiotics in the last century is considered one of the most important achievements in the history of medicine. Antibiotic usage has significantly reduced morbidity and mortality associated with bacterial infections. However, inappropriate use of antibiotics has led to emergence of antibiotic resistance at an alarming rate. Antibiotic resistance is regarded as a major health care challenge of this century.

In this work, we analysed processive sliding and breakage of actin filaments at various heavy meromyosin (HMM) densities and ATP concentrations in IVMA. We observed that with addition of ATP solution, the actin filaments fragmented stochastically; we then determined mean length and velocity of surviving actin filaments post breakage. Average filament length decreased with increase in HMM density at constant ATP and increased with increase in ATP concentration at constant HMM density. Using density of HMM molecules and length of actin, we estimated the number of HMM molecules per actin filament (N) that participate in processive sliding of actin. N is solely a function of ATP concentration: 88 ± 24 and 54 ± 22 HMM molecules (mean ± S.D.) at 2 mM and 0.1 mM ATP respectively. Processive sliding of actin filament was observed only when N lay within a minimum lower limit (N_min) and a maximum upper limit (N_max) to the number of HMM molecules. When N < N_min the actin filament diffused away from the surface and processivity was lost and when N > N_max the filament underwent breakage eventually and could not sustain processive sliding. We postulate this maximum upper limit arises due to increased number of strongly bound myosin heads.

We investigated the prevalence and diversity of antimicrobial resistance in bacteria isolated from urine samples of community-onset urinary tract infection (UTI) patients in southern Assam, India. Freshly voided midstream urine samples were collected from patients attending primary healthcare centres, with the patients’ epidemiological data also recorded. Species identification was confirmed using a VITEK 2 compact automated system. Phenotypic confirmation of ESBLs was performed using the combined disc diffusion method (CLSI 2017) and carbapenemase production was phenotypically characterized using a modified Hodge test. Common ESBLs and carbapenem-resistance mechanisms were determined in Escherichia coli isolates using PCR assays. Incompatibility typing of the conjugable plasmids was determined by PCR-based replicon typing; the phylotypes and MLSTs were also analysed. A total of 301 (59.7%) samples showed significant bacteriuria along with symptoms of UTI and among them 103 isolates were identified as E. coli of multiple STs (ST3268, ST3430, ST4671 and others). Among them, 26.2% (27/103) were phenotypically ESBL producers whereas 12.6% (13/103) were carbapenemase producers. This study describes the occurrence of diverse ESBL genes—bla_CTX-M-15, bla_SHV-148, bla_PER-1 and bla_TEM—and two E. coli isolates carrying the bla_NDM-1 carbapenemase gene. ESBL genes were located within transconjugable plasmids of IncP and IncF type whereas bla_NDM-1 was carried in an IncF_repB type plasmid. This study illustrates the high rate of MDR in E. coli causing UTI in primary care in rural Assam. UTIs caused by ESBL- or MBL-producing bacteria are very difficult to treat and can often lead to treatment failure. Thus, future research should focus on rapid diagnostics to enable targeted treatment options and reduce the treatment failure likely to occur with commonly prescribed antibiotics, which will help to combat antimicrobial resistance and the burden of UTIs.

The recorded field of view of any digital imaging system is limited by the physical size of the sensor array. While it is a common knowledge that the image field exists beyond the boundaries of the sensor array, there is generally no way to measure it unless the imaging system (or the object) is translated laterally. We propose a single-shot computational imaging system with a multiple-point impulse response that is able to effectively increase the physical size of the sensor array. The image recorded on the array sensor is not visually meaningful but can be used to recover the image field beyond the native sensor boundary via a sparsity based iterative algorithm, as we demonstrate in this work. The system concept can be considered analogous to structured illumination imaging; however, the structuring is performed here in the Fourier space in order to recover an extended image field. The effective increase in the sensor size depends on the extent of the impulses in the engineered multiple point impulse response. The achievable sensor size extension is therefore limited by the resolution of the phase mask that is introduced in the Fourier plane of the imaging system. We present a simulation study where the individual impulses in the designed impulse response extend over the original array sensor size, thereby doubling the effective sensor dimensions (a four times increase in the number of pixels) without affecting the image resolution. Both binary and gray-scale objects have been considered in our study in order to illustrate that the quality of the extended field of view image depends on the sparsity of the object under consideration. The concept of extended field of view computational imaging as presented here may find a number of practical applications.

An affordable immuno-magnetic cell capture system for bacterial detection in 7 hours with 10 CFU ml ⁻¹ sensitivity.

Total internal reflection fluorescence (TIRF) microscopy is widely used for selective excitation and high-resolution imaging of fluorophores, and more recently label-free nanosized objects, with high vertical confinement near a liquid–solid interface. Traditionally, high numerical aperture objectives (>1.4) are used to simultaneously generate evanescent waves and collect fluorescence emission signals which limits their use to small area imaging (<0.1 mm ² ). Objective-based TIRFs are also expensive as they require dichroic mirrors and efficient notch filters to prevent specular reflection within the objective lenses. We have developed a compact 3D module called cTIRF that can generate evanescent waves in microscope glass slides via a planar waveguide illumination. The module can be attached as a fixture to any existing optical microscope, converting it into a TIRF and enabling high signal-to-noise ratio (SNR) fluorescence imaging using any magnification objective. As the incidence optics is perpendicular to the detector, label-free evanescent scattering-based imaging of submicron objects can also be performed without using emission filters. SNR is significantly enhanced in this case as compared to cTIRF alone, as seen through our model experiments performed on latex beads and mammalian cells. Extreme flexibility and the low cost of our approach makes it scalable for limited resource settings.