Evaluation of the relationship between quantitative PCR results and cell culturing of SARS2-CoV with respect to symptoms onset and Viral load - a systematic review

BackgroundViral culture is currently the most accurate method to demonstrate viability and infectivity of Severe acute respiratory syndrome Coronavirus (SARS-2 CoV). Routine clinical diagnosis, however, is mostly performed by PCR - based assays that do not discriminate between infectious and non-virus. Herein, we aimed to determine the correlation between positive viral cultures and either PCR positivity, the Cycle Threshold (Ct) or the number of viral copies. MethodsA systematic electronic literature search was performed and studies that reported both viral SARS-CoV-2 culture and PCR-based assays were included. A separate search for samples from blood, urine, stool, breast milk and tears were performed. To convert Ct values reported in the reviewed studies were to viral genomic copies, calibration experiments with four different reaction performed, using quantified RNA molecules. ResultsA total 540 articles were reviewed, and 38 studies were included in this review. Out of 276 positive-culture of non-severe patients, 272 (98.55%) were negative ten days after symptoms onset, while PCR assays remained positive for up to 67 days. In severely ill or immunocompromised patients positive-culture was obtained up to 32 days and out of 168 cultures, 31 (18.45%) stayed positive after day 10. In non-severe patients, in Ct value greater than 30 only 10.8% were still culture-positive while in Ct >35 it was nearly universally negative. The minimal calculated number of viral genome copies in culture-positive sample was 2.5 x 103 copies / mL. These findings were similar in immunocompromised patients. Recovering positive culture from non-respiratory samples was sporadically obtained in stool or urine samples. Conversion of Ct values to viral genome copies showed variability between different PCR assays and highlighted the need to standardize reports to correctly compare results obtained in different laboratories. ConclusionDuring the pandemic phase, non-severe COVID-19 patients who are recovering and are not immuno-suppressed, can be regarded as non-infectious, within 10 days from symptom onset, or with Ct value greater than 35 (or a calculated viral load lower than 1.2x103 copies / mL). These findings have important implications for recovering patients and asymptomatic patients, with respect to isolation criteria. The conversion of Cq values to viral genome copies described herein may be useful in future work, enabling a more standardized comparison between results reported in different studies from different laboratories.

Israeli Arabs develop diverticulitis at a younger age and are more likely to require surgery than Jews.

BACKGROUND: Only few studies have examined the impact of racial differences on the age of onset, course and outcomes of diverticulitis. AIM: To provide data about the epidemiology of diverticulitis in northern Israel, and to determine whether ethnicity is a predictor of age of onset, complications, and need for surgery. METHODS: Was conducted a retrospective review of the charts of all patients diagnosed with a first episode of diverticulitis in our hospital between 2005 and 2012. RESULTS: Were found 638 patients with a first episode of acute diverticulitis in the eight year interval. Israeli Arabs developed a first episode of diverticulitis at a younger age compared to Jews (51.2 vs 63.8 years, p<0.01). Arabs living in rural areas developed diverticulitis at a younger age than Arabs living in urban centers (49.4 vs 54.5 years, P=0.03). Jewish and Arabic men developed diverticulitis at younger age compared to their female counterparts (59.9 vs 66.09, p<0.01, and 47.31 vs 56.93, p<0.01, respectively). Arabs were more likely [odds ratio (OR)=1.81 ,95% confidence interval (CI)1.12-2.90, p=0.017] than Jews to require surgical treatment (urgent or elective) for diverticulitis. CONCLUSIONS: Israeli Arabs tend to develop diverticulitis at a younger age and are more likely to require surgical treatment for diverticulitis compared to Jews. Arabs living in rural areas develop diverticulitis at a younger age than Arabs living in urban centers. These findings highlight a need to address the root cause for ethnic differences in onset, course and outcome of acute diverticulitis.

Israeli Arabs develop diverticulitis at a younger age and are more likely to require surgery than Jews / Árabes israelitas desenvolvem diverticulite em idade mais jovem e estão mais sujeitos ao tratamento cirúrgico do que os judeus

BACKGROUND: Only few studies have examined the impact of racial differences on the age of onset, course and outcomes of diverticulitis. AIM: To provide data about the epidemiology of diverticulitis in northern Israel, and to determine whether ethnicity is a predictor of age of onset, complications, and need for surgery. METHODS: Was conducted a retrospective review of the charts of all patients diagnosed with a first episode of diverticulitis in our hospital between 2005 and 2012. RESULTS: Were found 638 patients with a first episode of acute diverticulitis in the eight year interval. Israeli Arabs developed a first episode of diverticulitis at a younger age compared to Jews (51.2 vs 63.8 years, p<0.01). Arabs living in rural areas developed diverticulitis at a younger age than Arabs living in urban centers (49.4 vs 54.5 years, P=0.03). Jewish and Arabic men developed diverticulitis at younger age compared to their female counterparts (59.9 vs 66.09, p<0.01, and 47.31 vs 56.93, p<0.01, respectively). Arabs were more likely [odds ratio (OR)=1.81 ,95% confidence interval (CI)1.12-2.90, p=0.017] than Jews to require surgical treatment (urgent or elective) for diverticulitis. CONCLUSIONS: Israeli Arabs tend to develop diverticulitis at a younger age and are more likely to require surgical treatment for diverticulitis compared to Jews. Arabs living in rural areas develop diverticulitis at a younger age than Arabs living in urban centers. These findings highlight a need to address the root cause for ethnic differences in onset, course and outcome of acute diverticulitis. .

RACIONAL: Somente poucos estudos examinaram o impacto das diferenças raciais na idade de início, curso e os resultados da diverticulite. OBJETIVO: Fornecer dados sobre a epidemiologia da diverticulite no norte de Israel, e determinar se a etnia é preditor de idade de início, complicações e necessidade de tratamento cirúrgico. MÉTODOS: Foi realizado estudo retrospectivo dos prontuários de todos os pacientes diagnosticados com um primeiro episódio de diverticulite em nosso hospital entre 2005 e 2012. RESULTADOS: Foram encontrados 638 pacientes com um primeiro episódio de diverticulite aguda no intervalo de oito anos. Os árabes israelenses desenvolveram o primeiro episódio de diverticulite em idade mais jovem em comparação com os judeus (51,2 vs 63,8 anos, p<0,01). Árabes que vivem em áreas rurais a diverticulite foi desenvolvida em idade mais jovem do que os árabes que vivem em centros urbanos (49,4 vs 54,5 anos, p=0,03). Homens judeus e árabes desenvolveram diverticulite em idade mais jovem em comparação com os seus homólogos do sexo feminino (59,9 vs 66,09, p<0,01, e 47,31 vs 56,93, p<0,01, respectivamente). Os árabes eram mais prováveis ​​do que os judeus de necessitar de tratamento cirúrgico (urgência ou eletiva) para a diverticulite [odds ratio (OR)=1,81, intervalo de confiança de 95% (CI) 1,12-2,90, p=0,017]. CONCLUSÕES: Os árabes israelenses tendem a desenvolver diverticulite em idade mais jovem e são mais propensos a necessitar de tratamento cirúrgico para a diverticulite em comparação com os judeus. Árabes que vivem em áreas rurais desenvolvem diverticulite em idade mais jovem do que os árabes que vivem em centros urbanos. Estes resultados destacam a necessidade de abordar a causa raiz para diferenças étnicas em início, o curso e o resultado da diverticulite aguda. .