Molecular Characterization of Enterotoxigenic Escherichia coli: Effect on Intestinal Nitric Oxide in Diarrheal Disease Muhammad Arfat Yameen 1 , Ebuka Elijah David 2* , Humphrey Chukwuemeka Nzelibe 3 , Muhammad Nasir Shuaibu 3 , Rabiu Abdussalam Magaji 4 , Amakaeze Jude Odugu 5 and Ogamdi Sunday Onwe 6 1 Department of Pharmacy, COMSATS Institute of Information Technology, Abbottabad, Pakistan 2 Department of Biochemistry, Federal University, Ndufu-Alike, Ikwo, Ebonyi State, Nigeria 3 Department of Biochemistry, Ahmadu Bello University, Zaria, Kaduna State, Nigeria 4 Department of Human Physiology, Ahmadu Bello University, Zaria, Kaduna State, Nigeria 5 Medical Laboratory, Ahmadu Bello University, Teaching Hospital, Zaria, Kaduna State, Nigeria 6 Laboratory Service Unit, Federal Teaching Hospital, Abakiliki, Ebonyi State, Nigeria * Corresponding author: Ebuka Elijah David, Department of Biochemistry, Federal University, Ndufu-Alike, Ikwo, Ebonyi State, Nigeria, Tel: +2348033188823; E-mail: david.ebuka@funai.edu.ng Received date: May 01, 2018; Accepted date: May 25, 2018; Published date: May 30, 2018 Copyright: ©2018 Yameen MA, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract This study was aimed to investigate the effect of enterotoxigenic E. coli (ETEC)-induced diarrhea on fecal nitric oxide (NO) and intestinal inducible nitric oxide synthase (iNOS) expression in rats. E. coli isolates were gotten from infants diarrheal samples. Multiplex polymerase chain reaction (PCR) was used to detect the presence of eltA gene for heat-stable (ST) enterotoxigenic E. coli and eltB for heat-labile (LT) enterotoxigenic E. coli. Disk diffusion method was used to determine the antibiotic susceptibility of the organisms. Biofilm formation was detected by thiazoylblue tetrazolium bromide dye in a 96-well plate. Fecal NO was measured using standard griess reaction system. Reverse transcription PCR was used to investigate the expression of iNOS expression. Although none of the ETECs isolated in this study belonged to the classic serotype, serogroup O6 and O8 were found to be associated with ETECs. Among the three ETECs, two were found to be multidrug resistant. The biofilm production abilities of all the ETECs were found to exist between weak and moderate biofilm producers. Fecal NO was found to be elevated in both LT and ST-induced diarrheal groups but there was no corresponding intestinal iNOS expression. This suggests that the elevated NO could be as a result of up-regulation of constitutive NOS rather than iNOS. Keywords: Enterotoxigenic E. coli; Escherichia coli; Nitric oxide; Diarrheal disease Introduction Diarrhea is the second leading cause of death in children under the age of ive of which about 1.5 million die each year. his number represents nearly one in ive child deaths. More of these children die of diarrhea than AIDS, malaria and measles combined and greater percentage of this death due to diarrhea occur in Africa and South Asia of which Nigeria ranks second, with over 151,700 deaths per year [1]. Diarrhea can be deined as having watery stools for at least three times in a day or when it is more frequent than normal in an individual. It is a symptom of gastrointestinal infections that can be caused by bacteria, viruses, protozoa and other pathogens. However, the major organisms that cause most cases of childhood acute diarrhea are Rotavirus, E. coli, Shigella, Salmonella, Campylobacteria and Vibro cholera (during epidemics). hese pathogens are transmitted normally from the stool of one person to the mouth of another through diferent media like food or water [1]. Rotavirus and pathogenic E. coli are the most common cause of childhood diarrhea while Shigella spp. remains the most important causes of acute bloody diarrhea ( dysentery), accounting for about 15% of death in children under 5 years [2]. Escherichia coli are Gram-negative, oxidase-negative, rod-shaped bacterium from the family Enterobacteriaceae [3]. hey are commensal bacteria that can be found in intestinal micro lora of a variety of animals including man. Not all the strains of E. coli are harmless since some can cause debilitating and sometimes fatal diseases in humans as well as mammals and birds [4]. Pathogenic strains are divided into intestinal pathogens (InPEC) causing diarrhea and extraintestinal E. coli (ExPEC) causing a variety of infections including urinary tract infections (UTI), meningitis and septicemia [5]. InPEC strains of E. coli also known as diarrheagenic E. coli (DEC) is a major etiological agent of pediatric diarrhea, accounting for over 2 million deaths annually [6]. It continues to be the most common cause of infantile morbidity and mortality most especially in developing countries and sub-Saharan Africa [7] particularly in children under 5 years of age [8]. Nigeria records over 50,000 diarrhea-speciic mortality among children less than 5 years [3]. DEC can be transmitted via the oral-fecal route by ingesting food or water contaminated by human or animal feces [7]. An altered movement of ions and water in gastrointestinal tract is at the heart of diarrheal diseases. InPEC can alter the balance between luid-electrolyte absorption and secretion leading to diarrhea [9]. DEC are divided into enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enterohemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC) and difusely adherent E. coli (DAEC) based on their speciic virulence factors and phenotypic traits. Each pathological type has characteristic virulence determinants that contribute to its pathogenic mechanisms [10]. he prevalence and other epidemiological features of DEC types in childhood diarrhea vary with geographical area [6]. J o u r n a l o f B a c t e r i o l o g y & Pa r a s i t o l o g y ISSN: 2155-9597 Bacteriology and Parasitology Yameen et al., J Bacteriol Parasitol 2018, 9:3 DOI: 10.4172/2155-9597.1000339 Research Article Open Access J Bacteriol Parasitol, an open access journal ISSN:2155-9597 Volume 9 • Issue 3 • 1000339