proofreading & editing Background Bloodstream infections are the most common global cause of death attributed to infectious diseases (Tsuzuki et al., 2020). Of the two most common bacteria that account for the most cases of blood infection-induced mortality, Staphylococcus aureus (S. aureus ) stands out as the most pathogenic gram-positive bacteria (WHO, 2021). Surprisingly, S. aureus has also been identified as a normal flora, colonizing the nares, the skin as well as the perineum in an estimated one third of the human population, with an additional one third colonized intermittently (Thomer, Schneewind and Missiakas, 2016). S. aureus has been associated with skin and soft tissue infections as well as the more serious infection of the blood Stream, which if untreated results in more complicated sequels, septicemia and septic shock, that could ultimately lead to death (Thomer, Schneewind and Missiakas, 2016). Literature review S. aureus is among the most important causes of both hospital- and community-acquired blood stream infections worldwide (Reddy et al., 2010). S. aureus is the commonest significant blood culture isolate in hospitalized patients and the second commonest community-acquired isolate, accounting for around 20% to 25% of total blood culture isolates (Karlowsky et al., 2004). S. aureus is an opportunistic pathogen that normally colonizes the human anterior nares. At the same time, this pathogen is one of the leading causes of life-threatening bloodstream infections, such as sepsis (Kwiecinski, J. M., & Horswill, A. R., 2020). Resistance of S. aureus strains to antibiotics has been increasing especially MRSA strain; thus, the ability of these pathogens to spread in both hospital and community settings has increased (Chambers, H. F., & DeLeo, F. R., 2009). Increased antibiotic resistance, in addition to the increased frequency of invasive surgery, increased use of intravascular devices, and increased numbers of patients with immunocompromised status because of HIV infection or immunosuppression after transplantation or cancer treatment, has led to sharp increases in the incidence of SAB over the past 30 years (Naber, C. K., 2009). As illustrated by (Bahnasy, A. A., 2000),the episodes of SAB diagnosed at King Abdulaziz University Hospital (KAUH), Hospital-acquired infection was detected in 74% of the episodes versus 25% community-acquired. MRSA was found in 29% of the episodes versus 71% Methicillin sensitive S. aureus (MSSA) (Bahnasy, A. A., 2000). It is in the evolution of antibiotic resistant strains of the bacteria that clinical concern lies, as these develop resistance even against last resort therapeutics, increasing the rates of therapeutic failure, health care related costs as well as mortality (Thomer et al., 2016). The World Health Organization (WHO) considers the development of antimicrobial resistance as the most pressing global issue, reporting that 87% of countries engaged in its Global Antimicrobial Surveillance system and Use (GLASS) program isolated antibiotic resistant Staphylococcus aureus in samples from patients with confirmed bloodstream infections (BSIs) (WHO, 2021). Rates of this antibiotic resistant strain, termed methicillin-resistant S. aureus (MRSA), were reported more frequently in low and middle income countries (%) compared to high income countries (15%)(WHO, 2021). Rationale Addressing the potential to increase patient mortality & morbidity, the analysis of the prevalence of MRSA & MSSA in samples from patients with BSI will aid in the evaluation of the levels of antimicrobial resistance in the patients frequenting KAUH. The prevalence of BSI caused by in most regions of Saudi Arabia is still insufficient. For that reason, further epidemiological studies are required to determine the distributions and prevalence of S. aureus isolates for a proper management and develops the hospital infection control. Hypothesis Owing to the potential influence of human migration that has been identified as a potential risk factor for antimicrobial resistance dispersal, this study will work with the hypothesis that an increased burden of antimicrobial resistant S. aureus exists in patients with diagnosed BSI compared to antimicrobial sensitive S. aureus isolates. Method Objectives/Aims: This study will be a single center study that will employ Retrospective Record Review design to analyze data from Microbiology database. The aim of the study is to investigate the clinical epidemiology of BSI caused by the S. aureus bacteria in KAUH, which can facilitate the development of the hospital infection control and support the proper management of the resulting disease. Study Objectives 1. To investigate the prevalence of community and Hospital acquired sepsis caused by S. aureus in the KAUH. 2. To determine the antibiotic sensitivity test profiles (antibiograms) for all S. aureus isolates (MSSA & MRSA) with BSI. 3. To identify the source and strain of S. aureus and help improving the Policy of hospital infection control. Study Design Retrospective stages by the following stages: I. Stage one: Sample collection the bacterial isolates will be obtained from the clinical samples of positive blood cultures within 4 years (01-10-2017 to 01-10-2021). The study parameters will include the epidemiological and clinical characteristics of all patients with BSI caused by Staph. aureus bacteria without age restriction, defined by positive blood culture with signs and symptoms of infection. The study will be conducted according to ethical approval obtained from the Local Research Ethics Committee at KAUH. II. Stage two: Microbial identification of the bacterial isolates All blood cultures aerobic or anaerobic bottles will be incubated for 5 days in BACT/ALERT VIRTUO microbial detection system (FAN PLUS media and MYLA, bioMrieuxs). All positive blood bottle will be cultured as per standard method on 5% sheep blood agar, chocolate agar and MacConkey agar and incubated at 37c for 24 hrs. The Vitek 2 (Biomerieux Inc.,Durham,NC) GP cards (ID GP panel) were used for accurate identification of Gram positive pathogen and Vitek 2 AST cards (P580 panel), for antimicrobial susceptibility testing. BioFire (Biomerieux Inc.,Durham,NC) were used for immediate identification directly from blood bottle by molecular technology using BioFire Blood Culture Identification 2 (BCID2) Panel. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) (Bruker UK) for immediate and accurate identification using bacterial colony from cultural media. III. Stage three: Data analysis The samples results will be analyzed and evaluated using the appropriate statistical software (The IBM SPSS software). Continuous data will be assessed for normal distribution and will be log transformed as necessary to achieve normalcy so that the mean will be compared between the 4 independent groups using the one-way analysis of variants (ANOVA) NNSPSS software to determine any statistically significant differences between the means of independent groups. The significance level for the statistical tests will be aimed at for this study. References Al Musawi, S., Alkhaleefa, Q., Alnassri, S., Alamri, A., & Alnimr, A. (2021) Predictive Role of Targeted, Active Surveillance Cultures for Detection of Methicillin-Resistant Staphylococcus aureus. Infection and drug resistance. [Online] 14, 47574764. Available from [Accessed 23rd November 2021]. Bahnasy, A. A. (2000). Staphylococcus aureus bacteremia. Saudi medical journal, 21(2), 171-174.? Available from ?[Accessed 23rd November 2021]. Chambers, H. F., & DeLeo, F. R. (2009). Waves of resistance: Staphylococcus aureus in the antibiotic era. Nature Reviews Microbiology, 7(9), 629-641.? Available from ?[Accessed 23rd November 2021]. Karlowsky, J. A., Jones, M. E., Draghi, D. C., Thornsberry, C., Sahm, D. F., & Volturo, G. A. (2004). Prevalence and antimicrobial susceptibilities of bacteria isolated from blood cultures of hospitalized patients in the United States in 2002. Annals of clinical microbiology and antimicrobials, 3(1), 1-8.? Available from ?[Accessed 23rd November 2021]. Kwiecinski, J. M., & Horswill, A. R. (2020). Staphylococcus aureus bloodstream infections: pathogenesis and regulatory mechanisms. Current opinion in microbiology, 53, 51-60.? Available from ?[Accessed 23rd November 2021]. Naber, C. K. (2009). Staphylococcus aureus bacteremia: epidemiology, pathophysiology, and management strategies. Clinical infectious diseases, 48(Supplement_4), S231-S237.? Available from ?[Accessed 23rd November 2021]. Reddy, E. A., Shaw, A. V., & Crump, J. A. (2010). Community-acquired bloodstream infections in Africa: a systematic review and meta-analysis. The Lancet infectious diseases, 10(6), 417-432. Available from ?[Accessed 23rd November 2021]. Thomer, L., Schneewind, O., & Missiakas, D. (2016) Pathogenesis of Staphylococcus aureus Bloodstream Infections. Annual review of pathology. [Online] 11, 343364. Available from [Accessed 23rd November 2021]. Tsuzuki, S., Matsunaga, N., Yahara, K., Gu, Y., Hayakawa, K., Hirabayashi, A., Kajihara, T., Sugai, M., Shibayama, K., & Ohmagari, N. (2020) National trend of blood-stream infection attributable deaths caused by Staphylococcus aureus and Escherichia coli in Japan. Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy. [Online] 26(4), 367371. Available from [Accessed 23rd November 2021]. World Health Organization (WHO) (2021). Global antimicrobial resistance and use surveillance system (GLASS) report 2021. Available from [Accessed 23rd November 2021].Show more
