Procalcitonin and C-reactive protein as diagnostic biomarkers in COVID-19 and Non-COVID-19 sepsis patients: a comparative study.

BACKGROUND: This study aimed to assess and compare procalcitonin (PCT) and C-reactive protein (CRP) levels between COVID-19 and non-COVID-19 sepsis patients. Additionally, we evaluated the diagnostic efficiency of PCT and CRP in distinguishing between Gram-positive (GP) and Gram-negative (GN) bacterial infections. Moreover, we explored the associations of PCT with specific pathogens in this context. METHODS: The study included 121 consecutive sepsis patients who underwent blood culture testing during the COVID-19 epidemic. PCT and CRP were measured, and reverse transcriptase-polymerase chain reaction (RT-PCR) was employed for the detection of COVID-19 nucleic acid. The Mann-Whitney U-test was used to compare PCT and CRP between the COVID-19 and non-COVID-19 groups. Receiver operating characteristic (ROC) curves were generated to compare PCT and CRP levels in the GN group versus the GP group for assessing the diagnostic efficiency. The kruskal-Wallis H test was applied to assess the impact of specific pathogen groups on PCT concentrations. RESULTS: A total of 121 sepsis patients were categorized into a COVID-19 group (n = 25) and a non-COVID-19 group (n = 96). No significant differences in age and gender were observed between the COVID-19 and non-COVID-19 groups. The comparison of biomarkers between these groups showed no statistically significant differences. The optimal cut-off values for PCT and CRP in differentiating between GP and GN infections were 1.03 ng/mL and 34.02 mg/L, respectively. The area under the ROC curve was 0.689 (95% confidence interval (CI) 0.591-0.786) for PCT and 0.611 (95% CI 0.505-0.717) for CRP. The diagnostic accuracy was 69.42% for PCT and 58.69% for CRP. The study found a significant difference in PCT levels among specific groups of pathogens (P < 0.001), with the highest levels observed in Escherichia coli infections. The frequency of Staphylococcus spp. positive results was significantly higher (36.0%) in COVID-19 compared to non-COVID-19 sepsis patients (P = 0.047). CONCLUSION: Sepsis patients with COVID-19 revealed a significantly higher culture positivity for staphylococcus spp. than the non-COVID-19 group. Both PCT and CRP showed moderate diagnostic efficiency in differentiating between GP and GN bacterial infections. PCT showed potential utility in identifying E. coli infections compared to other pathogens.

Impact of COVID-19 on the distribution of pathogenic bacteria in the lower respiratory tract of the elderly.

BACKGROUND: To investigate the distribution of bacterial pathogens of lower respiratory tract infection (LRTI) in hospitalized elderly patients during the COVID-19 epidemic and to explore the influence of COVID-19 on the distribution of bacterial pathogens, to provide guidance for clinical diagnosis. METHODS: Specimens of sputum from elderly LRTIs patients at Fuding Hospital of China were consecutively collected from October 2022 to January 2023. Cultures and identification were done, and RT-PCR was employed to detect SARS-Cov-2 nucleic acid. RESULTS: A total of 195 isolates were characterized in 163 sputum samples of consecutive hospitalized elderly patients, of which 11.3% were Gram-positive bacteria and 88.7% were Gram-negative. The top of frequently isolated pathogens was Klebsiella pneumonia (30.3%), Pseudomonas aeruginosa (19.0%), Acinetobacter baumannii (12.8%), Stenotrophomonas maltophili, (7.7%), Escherichia coli (7.2%). According to the results of novel coronavirus nucleic acid detection, the 163 patients were divided into COVID-19 group and non-COVID control (CNT) group. The comparison of bacterial distribution between the groups revealed that Stenotrophomonas maltophilia was lower in the COVID-19 than in the CNT group, while A. baumannii was higher in the COVID-19 group, and the difference was statistically significant (p < .05). CONCLUSION: The major bacteria identified in sputum culture of hospitalized elderly patients were K. pneumonia, P. aeruginosa, A. baumannii, S. maltophilia, and E. coli. Furthermore, the distribution of S. maltophilia and A. baumannii between the COVID-19 and CNT groups was found to be significantly different (p < .05), while there were no significant differences in the distribution of other bacteria.