Clostridium perfringens is a spore-forming, Gram-positive anaerobic pathogen that causes several disorders in humans and animals. A multidrug-resistant Clostridium strain was isolated from the fecal sample of a patient who was clinically suspected of gastrointestinal infection and had a recent history of antibiotic exposure and diarrhea. The strain was identified by 16s rRNA sequencing as Clostridium perfringens. The strain’s pathogenesis was analyzed through its complete genome, specifically antimicrobial resistance-related genes. The Clostridium perfringens IRMC2505A genome contains 19 (Alr, Ddl, dxr, EF-G, EF-Tu, folA, Dfr, folP, gyrA, gyrB, Iso-tRNA, kasA, MurA, rho, rpoB, rpoC, S10p, and S12p) antibiotic-susceptible genetic species according to the k-mer-based detection of antimicrobial resistance genes. Genome mapping using CARD and VFDB databases revealed significant (p-value = 1 × 10⁻²⁶) genes with aligned reads against antibiotic-resistant genes or virulence factors, including phospholipase C, perfringolysin O, collagenase, hyaluronidase, alpha-clostripain, exo-alpha-sialidase, and sialidase activity. In conclusion, this is the first report on C. perfringens from Saudi Arabia that conducted whole genome sequencing of IRMC2505A and confirmed the strain as an MDR bacterium with several virulence factors. Developing control strategies requires a detailed understanding of the epidemiology of C. perfringens, its virulence factors, and regional antimicrobial resistance patterns.

Bacterial community diversity of bulk water and corresponding biofilms of four intensive care units' (ICUs) drinking water systems were studied and compared using 16S rRNA gene amplicons and next generation sequencing. Proteobacteria, mainly Alphaproteobacteria and Betaproteobacteria were dominant in the bulk water and biofilms. Principal component analysis showed different bacterial communities characterizing each of the bulk water and the biofilms in three of the studied ICUs. Taxonomic classification and comparison of different genera between samples highlighted the dominance of Aquabacterium (80%) and Novosphingobium (72%) in bulk water while biofilms harbored different bacteria affiliated to Pelomonas (97%) and Caulobacter (96%), Porphyrobacter (78%) and Staphylococcus (74%). Staphylococcus aureus was the only possible pathogen found with low percentage (2.32%) in three of the ICUs' biofilm and only in one of the ICU's bulk water. This study sheds light on the prevalence of unculturable bacterial flora in the biofilm ignored by the microbiological standard methods. This study was performed on tap and bulk water from ICUs; however, it indicates the need for further studies to investigate the function and activity of the microbial diversity in order to assess the real risk presented by this water microflora on patients' health.

Background & Objective: The COVID-19 pandemic imposed global concern and became one of the deadliest pandemics of the twenty-first century. Several vaccines were developed against SARS-CoV-2 to counteract the effects of this virus. This study aims to determine the post-vaccination side effects of the most common COVID-19 vaccines used in the Eastern province of Saudi Arabia. Methods: This is a cross-sectional study using an online questionnaire distributed randomly through social media. Frequencies were calculated to determine participants’ demographic information, vaccination details, and post-vaccination side effects. Univariate and multiple regression analysis were applied to test the association between individuals’ willingness to receive a booster dose and different categorical variables. Results: A total of 1004 participants were included in the survey, of which 0.6%, 85.3% and 14.1% completed either one, two or three doses of the Pfizer mRNA vaccine and Oxford AstraZeneca vaccines, respectively. The similar common side effects between the first and the second doses were significantly associated with the type of vaccine received; these included fatigue (Pfizer 54.4%, Oxford 73.2%; p < 0.001), headache (Pfizer 33.2%, Oxford 44.7%; p = 0.002), and fever (Pfizer 25.1%, Oxford 57.6%; p < 0.001). Additionally, unusual side effects were also reported (palpitations and menstrual abnormalities). Getting SARS-CoV2 infection after vaccination was significantly associated with the type of vaccine received at the first dose (Chi-Square=5.496, p = 0.019). A statistically significant association was found between the individuals’ willingness to receive a booster dose and their gender (Chi-Square = 39.493, p < 0.001), age (Chi-Square = 11.668, p = 0.02), presence of allergies (Chi-Square = 5.602, p = 0.018), and previous COVID-19 infection (Chi-Square = 9.495, p = 0.002). Conclusion: Despite the described side effects, further studies should be done to investigate the unusual and rare side effects to assess COVID-19 vaccines effectiveness and safety over longer period of time within a more diverse population.

Clostridioides difficile infection (CDI) has become a threatening public health problem in the developed world. In the kingdom of Saudi Arabia, prevalence of CDI is still unknown due to limited surveillance protocols and diagnostic resources. We used a two-step procedure to study and confirm C. difficile cases. We also studied toxin profiles of these isolates.