Background Coronavirus disease 2019 (COVID-19) is a devastating pandemic-causing disease with a variable severity among populations. Genetic studies have pinpointed angiotensin-converting enzyme 2 (ACE2), a key enzyme for viral entry, for its possible linkage to the disease progression. The present study aimed to investigate the potential association between single nucleotide polymorphisms (SNPs) of human ACE2 gene with the severity and outcomes of COVID-19 for better patient management. Methods In this observational cross-sectional study, COVID-19 confirmed patients were classified into moderate and severe cases according to the “Ain Shams University Hospitals Pocket Guide for COVID-19 Diagnosis.” Genetic analysis of ACE2 SNP rs2048683 was carried out using a TaqMan assay with the real-time polymerase chain reaction (PCR) technique. Results Among 90 confirmed COVID-19 patients, 78.9% (71/90) were classified as severe, and 21.1% (19/90) were classified as moderate. Laboratory biomarkers were significantly (P = 0.000) higher in the severe group than in the moderate group. Similarly, associated comorbidities such as hypertension were significant (P = 0.000) in the severe group, whereas asthma and deep venous thrombosis were significant in the moderate group (P = 0.007 and 0.006, respectively). Elevated serum ferritin level (odds ratio (OR) 162.589, 95% confidence interval (CI) 8.108–3260.293) and ACE2 rs2048683 genotype GG/G (OR 5.852, 95% CI 1.586–21.591) were both considered independent risk factors for severe disease. Conclusion The findings of the present study provide preliminary evidence of an association between ACE2 rs2048683 SNPs and COVID-19 severity in the Egyptian population, which may inform the need for targeted management.

The emergence of antibiotic-resistant biofilm producing microorganisms such as Pseudomonas aeruginosa has pushed efforts to find safe alternatives to antibiotics; such as probiotics. Lactobacilli are one of these promising probiotics, with reported antibacterial and anti-biofilm activity against many different pathogenic microorganisms. This study aimed to study the potential antibacterial and anti-biofilm effect of Lactobacillus acidophilus ATCC 4356, against the growth and biofilm formation of pathogenic P. aeruginosa. Cell free supernatant of L. acidophilus was tested to inhibit the growth; biofilm formation, and on preformed biofilms by 35 different clinical strains of P. aeruginosa, using agar well diffusion and microtitre plate assays. L. acidophilus ATCC 4356 recorded powerful growth inhibition against 88.6% of the P. aeruginosa strains. Moreover; it significantly inhibited biofilm formation of the strains by 68.52%, and removed already preformed biofilms with 43.8 % activity. Finally; L. acidophilus showed a potent inhibitory potential against the growth and biofilm formation by P. aeruginosa strains, thus could be used as a powerful probiotic for the bio-control of infections caused by antibiotic resistant and biofilm producing P. aeruginosa.