ABSTRACT

This study was conducted to determine the antibiotic resistance profile of Escherichia coli isolated from apparently healthy domestic livestock viz, cow, goats, and chicken from Akure, Ondo State Nigeria, E. coli was isolated using Eosin methylene Blue Agar (EMB) and identified by conventional microbiology technique. The isolate were tested against 14 antibiotics using the disc diffusion method. A total of 42 different antibiotics resistance profile were observed with each isolate showing resistance to at least four or more drugs tested. Generally the E. coli isolates showed resistance rates of 93.8% to ampicillin, 16.% to chloramphenicol, 57.5% to cloxacillin, 75.5% to Erythromycin, 20% to Gentamicin, 60.5% to penicillin, 19.5% to streptomycin, 25.8% to Ceftazidine, 45.8% to Cefuroxine,22.2% to cefixine 30.6% to Loxacin, 65.9% to augmentin, 26% nitrofurantoin, 29.3% to ciprofloxacin, 70.3% to tetracycline. This study showed that averages number of resistance phenotypes per isolate was significantly higher for goat and cow compared with poultry. A significant public health concern observed  in this study is that multi drug resistance commena E. coli strains may constitute a potential reservoir of resistance genes that could be transferred to pathogenic bacteria

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

Antibiotic resistance among microorganisms is a major problem, both in human and livestock industry. And the problem is usually attributed to unregulated and inappro- priate use of antibiotics (Witte, 1998; Lawson, 2008). It has been severally reported that commensal Escherichia coli isolates from healthy animals like cattle, swine as well as from humans play significant roles in the perpe- tration of drug resistant pathogens and subsequent infec- tions (Hunter et al., 1993; Shanahan et al., 1995; Sunde and Sⱷrum, 1999; Gulay et al., 2000; Kozak et al., 2009; Tian et al., 2012).

In Nigeria livestock industry, the problem of occurrence of multidrug resistant E. coli is becoming very rampart, because they are often encountered in routine diagnoses of disease conditions from livestock brought for con- firmatory diagnosis in microbiology diagnostic units of some Tertiary Veterinary Teaching Hospitals in Nigeria (unpublished data). Earlier in Nigeria, Ogunleye et al. (2008), reported nineteen different multidrug resistant patterns to commonly available antibiotic in E. coli isolated from some diseased poultry samples from eleven poultry farms in Abeokuta, Ogun State, Nigeria. The 39 E. coli were isolated from various organs like liver, lungs, kidneys, ovary, intestine and colo-rectum of birds that died of septicaemic conditions. Each of the E. coli isolates studied were resistant to between 5 and 12 com- monly used antibiotics such as nitrofurantoin, cefuroxime, norfloxacin, cotrimoxazole, nalidixic acid, chloramphe- nicol, ampicilin, ofloxacin, penincilin G, amoxylin, cloxa- cilin and ciprofloxacin(Ogunleye et al., 2008).

More recently, Ajayi et al. (2011) in a study, determined the antibiotic susceptibility patterns of commensal E. coli from feaces of apparently healthy cattle in Ado Ekiti, Ekiti State Nigeria from ready to slaughter cattle. They observed 74 different multiple antibiotic resistance patterns in the commonly used antibiotics, and 81% (851/1051) of the isolated E. coli showed resistance to at least 3 of the eight antibiotics tested, while 20 isolates showed resis- tance to all the eight antibiotics namely: ampicillin, cortri- moxazole, gentamicin, nalidixic acid, nitrofurantoin, colistin, streptomycin and tetracycline (Ajayi et al., 2011). Sub- sequently, from a group of 500 E. coli isolates tested for susceptibilities to fluoroquinolones (norfloxacin, levoflo- xacin, pefloxacin, ofloxacin and ciprofloxacin) and cepha- losporin group of drugs (ceftazidime, cefoxitin, ceftria- xone and aztreonam); the isolates were more sensitive to the cephalosporin group of drugs than to the fluoroquino- lones based drugs (Ajayi et al., 2011).

In another study from the South Eastern part of Nigeria, Nsofor and Iroegbu (2012), reported their observation on the antibiotic profiles of E. coli isolated from apparently healthy livestock like cattle, goat, poultry and swine. They observed 42 different antibiotic resistance profiles, with each isolates showing resistance to at least 4 or more of the antibiotics tested including: ampicilin, cortrimoxazole, cephalothin, streptomycin, nitrofurantoin, tetracycline, chloramphenicol, amoxicillin- clavulanic acid, cefpirome, cefpodoxime, cefotaxime, ceftriaxone, cefoxitin, nalidixic acid and gentamicin (Nsofor and Iroegbu, 2012).

In the developed world, the extensive use of antibiotics in agriculture, especially for prophylactic and growth promoting purposes, has generated much debate as to whether this practice contributes significantly to increased frequencies and dissemination of resistance genes into other ecosystems. In developing countries like Nigeria, antibiotics are used only when necessary, especially if the animals fall sick, and only the sick ones are treated in such cases. However, even in the absence of heavy use of antibiotics it is important to identify and monitor susceptibility profiles of bacterial isolates, particularly of commensal organisms. This, according to John and Fishman (1997), will provide information on resistance trends including emerging antibiotic resistance which are essential for clinical practice.

The current study was carried out to evaluate the current status of antibiotic resistance to commonly used antibiotics among the E. coli isolates from apparently healthy cattle at a major cattle market, located in Akure, Ondo State, Nigeria: where a large number of cities and towns in the South Western Nigeria States purchase cattle for slaughter for human consumptions.

1.2 Statement of the Problem

Antibiotic resistance in bacteria poses a significant public health threat globally, with Escherichia coli (E. coli) being a prominent pathogen contributing to this crisis. The rise of antibiotic-resistant E. coli, particularly from domestic livestock, is a pressing concern, especially in regions like Southwest Nigeria, where agricultural practices often involve the extensive use of antibiotics for both therapeutic and growth-promoting purposes (Ojo et al., 2022). The misuse and overuse of antibiotics in livestock can lead to the selection and proliferation of resistant strains, which can subsequently be transmitted to humans through the food chain, direct contact, or environmental pathways (Odeyemi et al., 2023).

In Nigeria, the impact of antibiotic resistance is compounded by the lack of effective surveillance systems and regulatory frameworks governing antibiotic use in the agricultural sector. Domestic livestock, such as cattle, sheep, and goats, are commonly administered antibiotics without adequate oversight, which fosters an environment conducive to the development of resistance (Ogunleye et al., 2021). Despite the potential health risks, there is limited research focusing on the antibiotic resistance profile of E. coli isolated from seemingly healthy domestic livestock in this region, making it difficult to assess the extent of the problem and formulate effective interventions.

Previous studies have indicated a high prevalence of antibiotic-resistant E. coli in livestock, with some isolates demonstrating multi-drug resistance (MDR) patterns (Adebayo et al., 2023). These findings raise alarms about the potential for these resistant strains to compromise animal health, food safety, and public health. The current knowledge gap necessitates a systematic investigation into the antibiotic resistance profiles of E. coli from apparently healthy domestic livestock in Southwest Nigeria. This study aims to identify prevalent resistance patterns, the mechanisms underlying resistance, and the implications for public health, thereby contributing to a better understanding of antibiotic stewardship in agriculture and informing policies aimed at mitigating the risks associated with antibiotic resistance.

The emergence and spread of antibiotic-resistant E. coli in livestock are critical issues that require urgent attention. The lack of comprehensive data on resistance profiles hinders the development of effective control strategies and poses a risk to both animal and human health. This research will provide valuable insights that can inform interventions to curb antibiotic resistance in livestock, enhance food safety, and protect public health in Southwest Nigeria.

1.3 Objectives of the study

The primary objective of this study is to assess antibiotics resistance profile of escherichia coli isolated from apparently healthy domestic livestock in South-West Nigeria. Specific objectives are:

To identify E. coli by biochemical test

To assess antibiotics resistance profile of escherichia coli from cow; chicken and goat in Akure, Ondo State.

1.4 Significance of the study

The study of the antibiotics resistance profile of Escherichia coli isolated from apparently healthy domestic livestock in South-West Nigeria is of paramount significance for several reasons. First, the findings contribute to the growing body of knowledge regarding antibiotic resistance in livestock, a critical issue that impacts both veterinary medicine and public health. Livestock is often treated with antibiotics to prevent disease and promote growth; however, the emergence of antibiotic-resistant strains of bacteria poses a significant threat to both animal and human health. Understanding the resistance profiles of E. coli in this context can inform better management practices in livestock farming and contribute to the development of effective strategies to mitigate antibiotic resistance.

Furthermore, this study has implications for food safety and public health. Escherichia coli is a common pathogen that can be transmitted from animals to humans through contaminated food products, direct contact, or the environment. The presence of antibiotic-resistant E. coli in livestock can lead to the transfer of these resistant strains to humans, complicating treatment options for infections. By characterizing the resistance patterns of E. coli from healthy livestock, the study highlights potential risks associated with the consumption of animal products, thereby underscoring the need for stringent monitoring and regulation of antibiotic use in livestock farming.

In addition, this research has significant implications for the development of policies and guidelines related to antibiotic use in agriculture. In many parts of the world, including Nigeria, there are limited regulations governing the use of antibiotics in livestock. The study's findings can serve as a vital resource for policymakers aiming to establish guidelines that balance the need for effective disease management in animals with the imperative to curb the rise of antibiotic resistance. By providing empirical data, this research can guide the formulation of more sustainable agricultural practices that promote the responsible use of antibiotics.

Moreover, the study addresses a gap in the existing literature regarding antibiotic resistance in Nigeria, particularly in the context of livestock. Most research on antibiotic resistance has primarily focused on clinical isolates from humans or specific animal diseases, leaving a significant knowledge gap concerning healthy livestock. By shedding light on the resistance profiles of E. coli in this population, the study paves the way for further investigations into the epidemiology of antibiotic resistance in animals and its potential implications for human health.

Lastly, this research holds educational significance by raising awareness among farmers, veterinarians, and the general public about the importance of responsible antibiotic use and the risks associated with antibiotic resistance. Through the dissemination of study findings, stakeholders can be educated about the impacts of antibiotic misuse in livestock production, leading to more informed decisions regarding animal husbandry practices.

1.5 Scope of the study

Broadly, this study focuses on antibiotics resistance profile of escherichia coli isolated from apparently healthy domestic livestock in South-West Nigeria. Specifically, this study will identify E. coli by biochemical test and assess antibiotics resistance profile of escherichia coli from cow; chicken and goat in Akure, Ondo State.

This study will be carried out in Akure, Ondo State.

1.6 Limitations of the study

Throughout the investigation, the researchers meticulously examined the fundamental limitations inherent in all human behaviours. A significant obstacle encountered was the insufficient examination in the scholarly investigation of the topic. A crucial element that influenced the circumstances was the restricted access to data concerning the topic at hand. In light of the undertaking, it proved to be quite challenging to locate the necessary materials, texts, or information, as well as to systematically arrange the data, necessitating a considerable allocation of time and effort. 

---

---