Persistence of SARS-CoV-2 RNA in the nasopharyngeal, blood, urine, and stool samples of patients with COVID-19: a hospital-based longitudinal study.

BACKGROUND: The persistence of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) RNA in the body fluids of patients with the novel coronavirus disease 2019 (COVID-19) may increase the potential risk of viral transmission. There is still uncertainty on whether the recommended quarantine duration is sufficient to reduce the risk of transmission. This study aimed to investigate the persistence of SARS-CoV-2 RNA in the nasopharyngeal, blood, urine, and stool samples of patients with COVID-19. METHODS: In this hospital-based longitudinal study, 100 confirmed cases of COVID-19 were recruited between March 2020 and August 2020 in Guilan Province, north of Iran. Nasopharyngeal, blood, urine, and stool samples were obtained from each participant at the time of hospital admission, upon discharge, 1 week after discharge, and every 2 weeks until all samples were negative for SARS-CoV-2 RNA by reverse transcription-polymerase chain reaction (RT-PCR) assay. A survival analysis was also performed to identify the duration of viral persistence. RESULTS: The median duration of viral RNA persistence in the nasopharyngeal samples was 8 days from the first positive RT-PCR result upon admission (95% CI 6.91-9.09); the maximum duration of viral shedding was 25 days from admission. Positive blood, urine, and stool RT-PCR results were detected in 24%, 7%, and 6% of the patients, respectively. The median duration of viral persistence in the blood, urine, and stool samples was 7 days (95% CI 6.07-7.93), 6 days (95% CI 4.16-8.41), and 13 days (95% CI 6.96-19.4), respectively. Also, the maximum duration of viral persistence in the blood, urine, and stool samples was 17, 11, and 42 days from admission, respectively. CONCLUSION: According to the present results, immediately after the hospitalized patients were discharged, no evidence of viral genetic materials was found. Therefore, appropriate treatments were selected for the patients at this hospital. However, we recommend further investigations on a larger sample size in multi-center and prospective randomized controlled trials (RCTs) to evaluate the effects of different drugs on the shedding of the virus through body secretions.

Intra-operative stone culture as an independent predictor of systemic inflammatory response syndrome after percutaneous nephrolithotomy.

To evaluate the correlation between preoperative urine culture and stone culture findings during PCNL and choosing the appropriate antimicrobial treatment of patients with urinary tract infection or SIRS after PCNL. From April 2007 to March 2008, 51 patients aged 24-66 years underwent PCNL under general anesthesia. Statistical analysis was performed using SPSS software (v.18), the Kolmogorov-Smirnov test, Student's t test, and the Chi square or Fisher's exact tests. Before operation, 11 patients (21.6 %) had positive urine culture. Sixteen patients (31.4 %) had positive stone culture during operation. SIRS occurred in 13 patients (25.5 %). In female group (10 cases, 45.5 %), SIRS was significantly higher than male group (3 cases, 10.3 %) (P = 0.008). Positive stone culture was significantly more prevalent in cases with positive pre-operative urine culture than cases with negative pre-operative urine culture (P = 0.023). But positive stone culture in group with SIRS, was significantly more common than group without SIRS (P = 0.001). Also positive stone culture in female group had significantly higher than male group (P = 0.003). We found a significant, tenfold increase in the risk of developing SIRS after PNCL, only in patients with positive stone culture (OR = 9.96; 95 % CI = 2.37-41.85, P = 0.002). Positive stone culture is a significant predictor of SIRS after PCNL, regardless of other related factors. Therefore, in order to avoid using blind empirical antibiotic regimen and to reduce the risk of subsequent microbial resistance due to use of prevalent broad-spectrum antibiotics, it would be wise to choose appropriate antibiotic therapy based on the results of intraoperative stone culture.