## 1 Introduction  
Recently, the World Health Organization (WHO) expected that worldwide death triggered by antibacterial-resistant pathogens would extend to 10 million people annually in 2050 [1]. A prospective study of hospital-acquired infections within four tertiary care university hospitals in Egypt within 2 years revealed that 86% and 94.6% of Gram-positive and Gram-negative isolates, respectively, were multidrug resistant (MDR) [2]. Studies indicate that antibiotic resistance is a high priority, markedly in the developing countries, with the exposure to microbial infections at hospitals being a major concern that requires careful study. Recently, the WHO has published a list of \"global priority pathogens\" (GPP) and indicated the urgent need for the discovery of potent antibacterial agents that can deal with these resistant pathogens [2]. MDR _Klebsiella pneumoniae_, Shiga toxin-producing _Escherichia coli_ O157 (STEC O157), Methicillin-resistant _Staphylococcus aureus_ (MRSA), and _Bacillus cereus_ are considered some of the most serious nosocomial pathogens causing hospital health care problems worldwide. According to the WHO, _K. pneumoniae_, _E. coli_,and _B. cereus_ are among the critical pathogens while _S. aureus_ is among the high priority pathogens [3]. STEC O157 is one of the major human and animal pathogens worldwide. It can cause several clinical manifestations ranging from stomach cramps and bloody diarrhea to pyelonephritis and hemolytic uremic syndrome (HUS) [2,4]. Additionally, based on the STEC O157 infected humans and animals' similarity analysis isolates, cross-infection between different hosts was obvious [5]. On the other hand, _K. pneumoniae_ is the most common clinical pathogen causing nosocomial infections [6]. Regarding the blood infection pathogens, _K. pneumoniae_ is second only to STEC O157, and carbapenem-resistant _K. pneumoniae_ that prompts blood infection has a great death rate [7]. The antibacterial research community must incessantly search together to develop new and safer medications to resolve the increasing drug resistance, along with toxicity challenges [8, 9, 10]. Historically, natural compounds have been a rich source of antibacterial therapies [11, 12, 13, 14]. One class of compounds that should be explored as an anti-bacterial is the alkaloids, such as carbazoles, where the Apocynaceae family presents a high content, particularly in the seeds and latex, and consequently should be explored [15]. Family Apocynaceae (periwinkle family or dogbane family) is one of the largest plant families, with roughly 400 genera and 1500 species. Apocynaceae is a flowering plants family, with trees, shrubs, herbs, or climbers [15]. An example of a plant from the Apocynaceae family is _Ochrosia_. This genus is of about 36 species, which are used as cytotoxic, anti-inflammatory, antioxidant, and anti-malarial agents. _Ochrosia ellpitica_ Labill. is a small tropical evergreen shrub native to Oceania in the tribe Vincee of the subfamily Rauvolfioideae. More than 40 different indole alkaloids have been recognized from the _Ochrosia_ species [16, 17]. They exhibited several biological activities, such as central nervous system stimulant, cytotoxic, antiseptic, and hypotensive [15, 18, 19]. In previous work, we were informed that elliptica, an alkaloid isolated from _Ochrosia ellpitica_ Labill. leaves, stopped topoisomerase IV activity, thus killing the multidrug-resistant _E. coli_, and revealed broad-spectrum antimicrobial bioactivities against several bacteria (_Staphylococcus aureus_, _Klebsiella pneumoniae_, _Listeria monocytogenes_, _Pseudomonas aeruginosa_, with _Salmonella typhi_) [20]. Additionally, ellipticines showed the most potent antibacterial activity against _E. coli_ and _S. aureus_ compared to the studied compounds (MIC \(<\) 2 mg/L) with an intact efflux mechanism of action, resulting in their development as effective antibacterial drugs [21].