Study of Microbial Infections and Some Immunological Parameters among Covid-19 in ICU Patients in Najaf Governorate, Iraq

The present study aimed to investigate some microbial infections and immunological parameters associated with Covid-19 patients admitted to the intensive care unit (ICU) of Al-Amal Specialized Hospital in AL-Najaf Governorate during February and March 2021. The study included 50 patients who were assigned to two groups: 20 patients aged ≤70 years and 30 patients aged ≥70 years. The method of microbial culture was adopted to isolate bacteria and yeasts by collecting sputum specimens and oral swabs from patients and cultivating them on diagnostic media and then confirming the diagnosis by Vitek. Moreover, serum samples were collected from patients’ blood to diagnose fungal infections. Thereafter, some immunological criteria were assessed, including Covid-19 diagnosis by measuring Immunoglobulin M (IgM) and IgG, as well as examining the concentration of cytokines (Interleukin 6 (IL-6) and IF ) using the enzyme-linked immunosorbent assay (ELISA) method. The results demonstrated that bacterial species Streptococcus pneumonia (n=5; 25%), Haemophilus Influenzae (n=7; 35%), and Moraxella catarrhalis (n=3; 15%) were isolated from the first group of patients (≤70 years). The recorded data pointed out that Streptococcus pneumonia (n=10; 33.3%), Streptococcus pyogenes (n=5; 16.6%), Streptococcus viridans (n=1; 3.3%), Haemophilus Influenzae (n=6; 20%), Mycobacterium tuberculosis (n=2; 6.6%), and Pseudomonas aeruginosa (n=2; 6.6%) were the isolated and identified microorganisms in the second age group (≥ 70 years). The results revealed that the isolated yeast from the first age group was Candida albicans (n=5; 25%) and Candida glabrata (n=3; 10%), while in the second age group, 1 (3.3%) Candida albicans was isolated. The results of this study proved that 30% and 10% of patients in the first and second age groups had invasive pulmonary aspergillosis co-infection by detecting Galactomannan (GM) in the blood serum (1.05±0.59, 1.25±0.38), respectively. The results indicated that IgM and IgG levels in the serum of patients in the first age group were 11.42±6.82 and 0.47±6.82, respectively. Moreover, the levels of IgM and IgG in the second age group were 14.84±9.21 and 0.12±0.11, respectively. Furthermore, IFɤ and IL6 levels were 98.37±65.70, and 146.12±46.35 in the first group, while IFɤ and IL6 were obtained at 110.69±47.60 and 133.28±116.94 in the second group, respectively. Elderly patients with severe COVID-19 are more frequently admitted to ICUs since the proportion of severe cases and comorbidities caused by a weakened immune system is higher among this age group. Secondary bacterial infections can also occur, especially Gram-negative bacteria which are among the most significant public health problems worldwide. Moroever, aspergillosis may infect patients hospitalized with COVID-19 and lead to death.