Antibiotic-resistant Staphylococci are a global issue affecting humans, animals, and numerous natural environments. Antibiotic-resistant Staphylococcus epidermidis is an opportunistic pathogen frequently isolated from patients and healthy individuals. This study aimed to examine the antibiotic resistance of S. epidermidis isolated from patients, healthy students and compare the results with antibiotic-resistant bacteria isolated from pasteurized milk. Clinical strain isolation was performed in several hospitals in the Riyadh. Skin swabs from 100 healthy undergraduate candidate students were obtained at King Saud University. The pasteurized milk samples were obtained from local market (company, X). After isolation, identification and susceptibility tests were performed using an automated system. A multiplex tuf gene-based PCR assay was used to confirm identification. Biofilm production and biofilm-related gene expression were studied. S. epidermidis represented 17% of clinical bacterial isolates, and 1.7% of isolates obtained from healthy students were multiantibiotic-resistant. All patient strains were teicoplanin- and vancomycin-susceptible, while all student strains were gentamicin-, levofloxacin-, moxifloxacin-, and trimethoprim/sulfamethoxazole-susceptible. All the bacteria isolated from pasteurized milk were benzylpenicillin and oxacillin-resistant strains. Of the S. epidermidis strains, 91% could produce biofilms, and mecA, icaADBR, ica-ADB, ica-AD, ica-A only, and ica-C only were expressed in 83, 17.1, 25.7, 37.1, 20, and 0% of the strains, respectively. This work demonstrates that S. epidermidis can be accurately identified using a multiplex tuf-based assay, and that multiantibiotic-resistant S. epidermidis strains are widespread amongst patients and healthy students.

The beneficial live microbes of humans and animals are termed probiotics, and the chemical compounds that improve the growth of probiotics are known as prebiotics. Paraprobiotics and postbiotics refer to dead or inactivated living cells of probiotics and healthful metabolic products that are produced by the living cells of probiotics, respectively. Although the healthful, functional, nutritional, and immune benefits of probiotics and prebiotics are scientifically well established beyond a reasonable doubt, their potential biological roles against COVID-19 infection still warrant further clinical and laboratory investigation.

The upgrowth and rapid prevalence of pandrug-resistant Acinetobacter baumannii strains that have a pathogenic activity to cause several infections are of considerable influence on the health of communities worldwide. No infections by these bacterial strains were recorded before 1998, and currently, the numbers are on the rise. The A. baumannii strains were isolated from male and female patients in Medical Microbiology Department, King Fahd Medical City (KFMC) in Riyadh, Saudi Arabia between 1/1/2020 to 29/12/2020. The statistical analysis was performed base on sex, age, source of samples, and response to commercially available antibiotics. The A. baumannii strains that resisted all the antibiotics including colistin and imipenem were selected for the synergic test. The data showed that 62.28%, 77.07% of 342 A. baumannii strains were isolated from males and patients over 35 years of age. A. baumannii strains (pandrug-A. baumannii) that can resist all tested antibiotics were 8.19%. The major source of the A. baumannii isolates was the respiratory system (>50%). Among all isolates (N = 342), azidothymidine-resistant A. baumannii strains were more than 85%. There is a statistically significant difference (P < 0.05) in the number of colistin-resistant A. baumannii strains isolated from males comparing with the female. The combinations of colistin and silver nanoparticles or imipenem and silver nanoparticles resulted in synergistic action led to reduction of MICs of colistin, imipenem, and silver nanoparticles (more than four-fold reduction). Also, the combinations of colistin and imipenem had high synergistic action. The pandrug-resistant A. baumannii strains may represent a current and future threat that must be fought, and the synergy action of antibiotics and nanoparticles may be one of the available, rapid, and easy strategies to confront this global problem.

Antibiotic-resistant bacteria are one of the major global health issues that can affect humans, animals, and the environment. Antibiotic-resistant bacteria have emerged as opportunistic pathogenic bacteria that are frequently isolated from both clinical patients and healthy individuals. The aim of this study was to characterize the antibiotic-resistant bacteria isolated from powdered infant formulas marketed in Riyadh, Saudi Arabia. Infant powdered milk formulas were purchased from different pharmacies located within Riyadh, and ten products of powdered milk formulas designed for children of various ages were then transferred to the laboratory in the Department of Botany and Microbiology at King Saud University, Riyadh. Isolation and purification of Bacillus species were both performed according to standard protocols. The identification test was performed using the automated Vitek 2 system (BioMerieux, France), and antibiotic sensitivity tests were performed using the disk-diffusion method incorporating standard antibiotic disks foramikacin (30μg/disk), gentamicin (10μg/disk), imipenem (10μg/disk), moxifloxacin (5μg/disk), cefoperazone (75μg/disk), cefpodoxime (10μg/disk), ceftazidime (30μg/disk), and cefepime (30μg/disk). Statistical analysis was performed using Ward's method to obtain antibiotic resistance of the isolates. The results obtained from the milk samples indicated that all isolates were sensitive to amikacin, gentamicin, and moxifloxacin. A group of isolates obtained from milk was resistant to cefoperazone by 6.49%, cefpodoxime by 25.9%, ceftazidime by 14.28%, and cefepime by 19.48%. Based on these findings, we concluded that the powdered infant formula marketed in Riyadh City may act as a source of bacterial isolates that are resistant to several standard antibiotics.