Background To detect carbapenemase-producing Gram-negative bacteria in bacterial laboratories at medical settings, a new immunochromatographic assay for New Delhi metallo-β-lactamases (NDMs) was developed. Methods The immunochromatographic assay for New Delhi metallo-β-lactamases producers was developed using rat monoclonal antibodies against NDMs. The assessment was performed using 350 isolates of Gram-negative bacteria, including Acinetobacter baumannii (51 isolates), Enterobacteriaceae (163 isolates), and Pseudomonas aeruginosa (136 isolates) obtained from 2015 to 2017 in medical settings in Myanmar. Of them, 302 isolates were resistant to carbapenems, including imipenem and/or meropenem. The bla NDM genes were identified by PCR and sequencing. Results Of the 350 clinical isolates tested, 164 (46.9%) (60 isolates of Escherichia coli , 51 isolates of Klebsiella pneumoniae , 25 isolates of Enterobacter cloacae , 23 isolates of P. aeruginosa , and 5 isolates of A. baumannii ) were positive on this assay, and all the positive isolates harbored genes encoding NDM-1, − 4, − 5 and − 7. The remaining 186 (53.1%) isolates negative on the assay did not harbor genes encoding NDMs. The assay had a specificity of 100% and a sensitivity of 100%. The assessment revealed that more than 90% of carbapenem-resistant Enterobacteriaceae produced NDMs. Conclusions The immunochromatographic assay is an easy-to-use and reliable kit for detection of NDMs-producing Gram-negative bacteria. The assay revealed that NDM-producing Enterobacteriaceae isolates are wide-spread in medical settings in Myanmar. Electronic supplementary material The online version of this article (10.1186/s12879-019-4147-4) contains supplementary material, which is available to authorized users.

Background The novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for the worldwide coronavirus disease-19 (COVID-19) pandemic, starting in late 2019. The standard diagnostic methods to detect SARS-CoV-2 are PCR-based genetic assays. Antigen-antibody-based immunochromatographic assays are alternative methods of detecting this virus. Rapid diagnosis kits to detect SARS-CoV-2 are urgently needed. Study design Three monoclonal antibodies against SARS-CoV-2 nucleocapsid (N) protein were used to develop an antigen-antibody-based immunochromatographic kit to detect SARS-CoV-2. These assays were evaluated using　 nasopharyngeal swab specimens collected from patients suspected of having COVID-19. Results These assays detected recombinant SARS-CoV-2 N protein at concentrations >0.2 ng/ml within 10 minutes after protein loading, but did not detect the N proteins of Middle East respiratory syndrome coronavirus (MERS-CoV), human coronaviruses OC43 (HCoV-OC43) and 299E (HCoV-229E) and other pathogens causing respiratory infections. Nasopharyngeal swab specimens obtained 1～3, 4～9, and ≥ 10 days after symptom onset from COVID-19 patients diagnosed by RT-PCR showed positivity rates of 100%, >80%, and <30%, respectively. Conclusions Kits using this immunochromatographic assay may be a rapid and useful tool for point-of-care diagnosis of COVID-19 when samples are obtained from patients 1～9 days after symptom onset.

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An immunochromatographic kit was developed to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses (A and B) on two detection positions of a single strip. The sensitivity and specificity for SARS-CoV-2 were 97.4% and 100%, respectively, and those for influenza viruses were 100%, respectively.

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