Background & objectives: Coronavirus disease 2019 (COVID-19) has so far affected over 41 million people globally. The limited supply of real-time reverse transcription-polymerase chain reaction (rRT-PCR) kits and reagents has made meeting the rising demand for increased testing incompetent, worldwide. A highly sensitive and specific antigen-based rapid diagnostic test (RDT) is the need of the hour. The objective of this study was to evaluate the performance of a rapid chromatographic immunoassay-based test (index test) compared with a clinical reference standard (rRT-PCR). Methods: A cross-sectional, single-blinded study was conducted at a tertiary care teaching hospital in north India. Paired samples were taken for RDT and rRT-PCR (reference standard) from consecutive participants screened for COVID-19 to calculate the sensitivity and specificity of the RDT. Further subgroup analysis was done based on the duration of illness and cycle threshold values. Cohen's kappa coefficient was used to measure the level of agreement between the two tests. Results: Of the 330 participants, 77 were rRT-PCR positive for SARS-CoV-2. Sixty four of these patients also tested positive for SARS-CoV-2 by RDT. The overall sensitivity and specificity were 81.8 and 99.6 per cent, respectively. The sensitivity of RDT was higher (85.9%) in participants with a duration of illness ≤5 days. Interpretation & conclusions: With an excellent specificity and moderate sensitivity, this RDT may be used to rule in COVID-19 in patients with a duration of illness ≤5 days. Large-scale testing based on this RDT across the country would result in quick detection, isolation and treatment of COVID-19 patients.

Objectives To ascertain if topical lignocaine application in oropharynx prior to swab sampling to test for COVID-19 improves a patient's comfort and to assess its effect on the swab sample taken to conduct the RT-PCR. Methods Adult patients testing positive on the RT-PCR COVID-19 test were sampled again within 48 h after administering topical oropharyngeal anaesthesia. Patients were asked to rate their discomfort on a visual analog scale (VAS) for both sample A and B. A qualitative real-time RT-PCR for detection of SARS-CoV-2 RNA, was performed, and the cycle threshold value (Ct), used as a surrogate marker for the viral load, was measured for the sample taken without lignocaine (sample A) and the sample taken post-lignocaine application (sample B). The difference in Ct values of both the groups was checked for any statistical significance using paired t-test. Wilcoxon signed rank test was used on VAS scores to determine any significant decrease in discomfort. Results Forty patients were included in the study. Twenty-nine patients (72.5%) reported the procedure to be more comfortable post-lignocaine application. Median (IQR) discomfort on VAS decreased from 7 (1) to 5 (2) after lignocaine use, which was statistically significant (p < 0.05). Mean Ct value for sample A was 17.21 ± 5.25 and for sample B was 18.44 ± 4.8 (p > 0.05), indicating a non-significant effect of lignocaine on SARS-CoV-2 concentration in the sample. Conclusion Topical lignocaine, while improving the comfort of the procedure of oropharyngeal sampling for patient did not alter the SARS-CoV-2 viral load that was detected in nasal and oropharyngeal samples taken together.

Aeromonas is a Gram-negative bacillus, widely found in aquatic environment. Osteoarticular pathology caused by Aeromonas hydrophila is rarely encountered. To the best of our knowledge, this is the first case of chronic osteomyelitis by A. hydrophila reported from India. We report a case of chronic osteomyelitis of the lower limb due to A. hydrophila, which occurred as a delayed complication following open reduction and internal fixation. Prompt medical and surgical intervention supplemented by a comprehensive microbiological workup aided in pathogen identification and specific antimicrobial administration resulting in the successful outcome of our patient. This case illustrates the utility of multidisciplinary management approach involving microbiologists and orthopedicians in investigating and appropriately managing such cases.

SIGNIFICANCE The significance of the study is that, although conventional culture remains the criterion standard for identifying the causative fungal pathogens, polymerase chain reaction (PCR) may serve as a powerful and high-throughput tool for the early and definitive diagnosis of high-risk patients with mycotic keratitis owing to high sensitivity and specificity. PURPOSE This study was focused on comparing the results of PCR with traditional microbial studies for the detection and identification of fungal pathogens in patients with clinically suspected fungal keratitis. METHODS Corneal scrapings were collected from 59 patients with clinically suspected fungal keratitis for routine culture, staining, and seminested PCR assay for fungal pathogen identification. The results of PCR were compared with a conventional microbial workup (smear and culture). The samples that were unidentified by culture but were amplified by PCR were further identified by nucleotide sequencing. RESULTS Of the 59 patients with suspected fungal keratitis, 38 (64.40%) were found to be positive by PCR assay, 24 (40.67%) by culture, 18 (20.3%) by potassium hydroxide wet mount, and 8 (13.5%) by Gram stains for fungal pathogens. All the 24 isolates found positive with culture were also positive with PCR, so they had not been sequenced for molecular identification. The remaining 14 isolates that were positive with PCR but negative with culture were further identified as Cladosporium cladosporioides, Simplicillium species, Fusarium solani, Alternaria tenuissima, Chaetomium globosum, Penicillium citrinum, and Rhizopus microsporus by sequencing up to the species level. CONCLUSIONS The PCR was able to detect the presence of fungal pathogens in a high proportion of culture-negative cases. This study suggests that PCR may serve as a rapid, important complement to traditional culture with high-throughput means of fungal pathogen identification in patients with clinically suspected fungal keratitis.

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