Pathogenic bacteria contribute to many globally important diseases, such as pneumonia, urinary tract infection, foodborne illnesses, and others.The present study aims to study and survey different isolates of pathogenic bacteria from different countries to assess their prevalence and their relation to diseases.Two hundred and ninety-two clinical samples were collected randomly from private laboratories and Hospitals of three countries (Egypt, Saudi Arabia, and Sudan). All samples were collected from patients (male and female) for ages from one to 89 years during the period 2015-2016. Samples included the present study were urine (168), vaginal swab (43), ear swab (22), blood (19), abscess (17), endotracheal tube (8), sputum (8), throat swab (3), nasal swab (3), and urethral swab (1). All samples were inoculated on different selective and differential culture media. After growth, isolated bacteria were identified by physiological and biochemical properties.Mainly 5 bacterial genera were detected amongst all clinical samples. The isolates were identified to be Escherichia coli (103), Klebseilla spp. (47), Proteus spp. (14), Pseudomonas spp < em>. (83), and Staphylococcus spp. (45). Regarding patient gender, the presented study showed that females had a tendency to get infected more than males, where 110 (37.67 %) of patients were males and 182 (62.33 %) were females. The most common microbes in urinary tract infection were Escherichia coli. The most common microbes in acute otitis externa were Pseudomonas aeruginosa and Staphylococcus aureus. All isolates from abscesses were Pseudomonas aeruginosa and Staphylococcus aureus. The results showed that Pseudomonas aeruginosa was the most common isolated samples and only Proteus mirabilis were isolated urine samples. Survey and studies for infectious agents are one of the most significant epidemiological tools to track infectious disease and to foretell disease patterns, as well as determining the distribution of agents according to body parts. Pathogenic bacteria contribute in many globally important diseases.