The purpose of this study is to evaluate the frequency of viral and bacterial respiratory pathogens detected by molecular methods in sputum samples of patients hospitalized for COVID-19 and to evaluate its impact on mortality and unfavorable outcomes (inhospital death or mechanical ventilation). Patients and Methods: The prospective cohort included patients with diagnosis of COVID-19 hospitalized at Hospital Nacional Hipólito Unanue. Sociodemographic and clinical data were collected from clinical records. Sputum samples were analyzed with the Biofire Filmarray Pneumonia plus ® respiratory panel. Crude and adjusted associations with unfavorable outcomes were evaluated using logistic regression models. Results: Ninety-three patients who were able to collect sputum samples were recruited between September 8 and December 28, 2020. The median age was 61.7 years (IQR 52.3-69-8) and 66 (71%) were male. The most frequent symptoms were dyspnea, cough, fever, and general malaise found in 80 (86%), 76 (82%), 45 (48%), and 34 (37%) patients, respectively. Fifty-three percent of patients had comorbidities. Seventy-six (82%) patients received antibiotics prior to admission and 29 (31%) developed unfavorable outcome. Coinfection was evidenced in 38 (40.86%) cases. The most frequently found bacteria were Staphylococcus aureus, Streptococcus agalactiae, Haemophilus influenzae and Klebsiella pneumoniae in 11 (11.83%), 10 (10.75%), 10 (10.75%), and 8 (8.6%) cases, respectively. Streptococcus pneumoniae was found in one case (1.08%). We neither identify atypical bacteria nor influenza virus. No association was found between the presence of viral or bacterial microorganisms and development of unfavorable outcomes (OR 1.63; 95% CI 0.45-5.82). Conclusion:A high frequency of respiratory pathogens was detected by molecular methods in patients with COVID-19 pneumonia but were not associated with unfavorable outcomes. No atypical agents or influenza virus were found. The high use antibiotics before admission is a concern. Our data suggest that the use of drug therapy against atypical bacteria and viruses would not be justified in patients hospitalized for COVID-19.
Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a major threat to public health. Rapid molecular testing for convenient and timely diagnosis of SARS-CoV-2 infections represents a challenge that could help to control the current pandemic and prevent future outbreaks. We aimed to develop and validate a multiplex and colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay using lyophilized LAMP reagents for sensitive and rapid detection of SARS-CoV-2. LAMP primers were designed for a set of gene targets identified by a genome-wide comparison of viruses. Primer sets that showed optimal features were combined into a multiplex RT-LAMP assay. Analytical validation included assessment of the limit of detection (LoD), intra- and inter-assay precision, and cross-reaction with other respiratory pathogens. Clinical performance compared to that of real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) was assessed using 278 clinical RNA samples isolated from swabs collected from individuals tested for COVID-19. The RT-LAMP assay targeting the RNA-dependent RNA polymerase (RdRp), membrane (M), and ORF1ab genes achieved a comparable LoD (0.65 PFU/mL, CT=34.12) to RT-qPCR and was 10-fold more sensitive than RT-qPCR at detecting viral RNA in clinical samples. Cross-reactivity to other respiratory pathogens was not observed. The multiplex RT-LAMP assay demonstrated a strong robustness and acceptable intra- and inter-assay precision (mean coefficient of variation, 4.75% and 8.30%). Diagnostic sensitivity and specificity values were 100.0% (95% CI: 97.4–100.0%) and 98.6% (95% CI: 94.9–99.8%), respectively, showing high consistency (Cohen’s kappa, 0.986; 95% CI: 0.966–1.000; p<0.0001) compared to RT-qPCR. The novel one-step multiplex RT-LAMP assay is storable at room temperature and showed similar diagnostic accuracy to conventional RT-qPCR, while being faster (<45 min), simpler, and cheaper. The new assay could allow reliable and early diagnosis of SARS-CoV-2 infections in primary health care. It may aid large-scale testing in resource-limited settings, especially if it is integrated into a point-of-care diagnostic device.
Despite widespread vaccination, Bordetella pertussis continues to cause pertussis infections worldwide, leaving infants at the highest risk of severe illness and death, while people around them are likely the main sources of infection and rapidly spread the disease. Rapid and less complex molecular testing for the specific and timely diagnosis of pertussis remains a challenge that could help to prevent the disease from worsening and prevent its transmission. We aimed to develop and validate a colorimetric loop-mediated isothermal amplification (LAMP) assay using a new target uvrD_2 informed by the pangenome for the specific and early detection of B. pertussis. Compared to that of multitarget quantitative polymerase chain reaction (multitarget qPCR) using a large clinical DNA specimen (n = 600), the diagnostic sensitivity and specificity of the uvrD_2 LAMP assay were 100.0% and 98.6%, respectively, with a 99.7% degree of agreement between the two assays. The novel colorimetric uvrD_2 LAMP assay is highly sensitive and specific for detecting B. pertussis DNA in nasopharyngeal swabs and showed similar diagnostic accuracy to complex and high-cost multitarget qPCR, but it is faster, simpler, and inexpensive, which makes it very helpful for the reliable and timely diagnosis of pertussis in primary health care and resource-limited settings.
Background Despite widespread vaccination, pertussis has re-emerged as a serious public health concern worldwide. Since 2017, Peru has experienced an increase in pertussis cases exhibiting a higher risk of severity and death in young infants. Thus, a dose of the Tetanus, Diphtheria, and Acellular Pertussis (Tdap) vaccine is recommended for pregnant women in the third trimester. Although evidence suggests the maternal Tdap vaccine is safe and effective, its association with a reduced risk of pertussis in developing countries remains poorly investigated. Methods We conducted a case-control study to evaluate the association between Tdap vaccination during pregnancy and reduction in the risk of pertussis among infants aged <2 months in Peru. Pertussis cases and controls treated in healthcare facilities nationwide between 2019 and 2021 and confirmed by real-time polymerase chain reaction were included. The controls were randomly selected from test-negative patients. Odds ratios (ORs) and vaccine effectiveness (VE) were calculated using a multiple logistic regression model and 1 − (OR) × 100%, respectively. Results Fifty cases and 150 controls were included in the analysis. The mothers of 4% of cases and 16.7% of controls received Tdap vaccination during pregnancy, resulting in an OR of 0.19 (95% CI, 0.04-0.86) and VE of 81% (95% CI, 14%-96%) for preventing pertussis in infants. Conclusions Peruvian infants <2 months old whose mothers received the Tdap vaccine in the third trimester of pregnancy had a significantly lower risk of pertussis. Tdap vaccination is thus an effective intervention to reduce the burden of pertussis in at-risk populations.
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