Project Materials

PREVALENCE OF MULTIDRUG RESISTANT LIVESTOCK ASSOCIATED STAPHYLOCOCCUS AUREUS ISOLATED FROM NASAL PASSAGE OF HEALTHY CATTLE

ABSTRACT

The facultative anaerobic Gram-positive coccal bacterium Staphylococcus aureus is known as “one of the most adaptable and virulent pathogens in modern times.” It may infect any human tissue and cause anything from a mild skin infection to a potentially fatal condition. The bacterium can cause zoonosis when it colonises and infects domestic animals and wild animals such as pigs, horses, rabbits, dogs, cats, and cattle.The fact that pets and livestock are common hosts to persistent multidrug-resistant S. aureus is quite concerning, since these animals and pets could act as reservoirs for human colonisation, adding to the difficulty of preventing the spread of infectious illnesses over the world. The purpose of this study was to determine how common it is to find resistant strains of Staphylococcus aureus in healthy cattle in Kara Market in Ogun state, Nigeria. Using Gramme staining and specific biochemical tests, 409 S. aureus isolates were detected from 500 nasal samples collected from healthy adult cattle. Of these, 218 were found in male cattle and 191 were found in female calves. Every single one of the S. aureus bacteria tested showed multidrug resistance in the antibiogram. This meant that none of the bacteria could be treated with any of these drugs: ceftriaxone, gentamicin, cotrimoxazole, erythromycin, amoxicillin, streptomycin, chloramphenicol, ampicillin, quinolones, and vancomycin. Out of all the isolates tested, 63.3% showed a high minimum inhibitory concentration (MIC) of 128 μg/ml or higher against flucloxacillin (methicillin), whereas 28% showed the same level of resistance (MIC>128 μg/ml) to vancomycin (glycosidic). It is clear that flucloxacillin and ampicillin are not a good combination for controlling staphylococcal infections because their in-vitro combined effect on the isolates was 86.3% additive. In this investigation, it was found that vancomycin killed bacterium that was connected with cattle and was resistant to methicillin and other drugs. To supplement or replace toxic antibiotics in the treatment of infections caused by multidrug-resistant Staphylococcus aureus, the quinolone antibiotics (ofloxacin, ciprofloxacin, and pefloxacin) are known to be relatively non-toxic and quite effective.

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study 

Ruminants with big bodies, cattle graze on grass and other plant foods. Cattle are mostly raised in Nigeria for their meat and milk, which are both excellent sources of protein for people (Arowolo et al., 2013).

In northern Nigeria, where there are only a handful of native settlements, the Fulani and Shuwa Arabs continue an ancient tradition of cattle raising (Erebor, 2003).

A facultative anaerobic gram-positive coccal bacterium, Staphylococcus aureus is a potent pathogen thanks to its arsenal of immune-evasive tactics. Numerous body locales can harbour this bacterium, although the nasal passages are thought to be the principal habitat and greatest supply of S. aureus in humans (Kluytmans et al., 1997; Lowy, 1998; Lowy, 2003). (Vandenbergh & Verbrugh, 1999).

Skin, the perineum, the axillae, the vagina, and the gastrointestinal system are common places to find S. aureus (Lowy, 2003; Williams, 1963; Ridley, 1959; Guinan et al., 1982; Williams, 1963). Significant human pathogens, S. aureus strains can infect any human body tissue, causing anything from skin infections to fatal diseases.

In humans, S. aureus infections can be broadly categorised into three types of sores: shallow sores (e.g., infections at surgical sites and wounds), life and systemic compromising factors (e.g., osteomyelitis, endocarditis, pneumonia, brain abscesses/wounds, bacteraemia, and meningitis), and finally, toxic nosodes (e.g., poisonous shock disorder, food poisoning, and singed skin disorder) (Alo et al., 2013; Aires de Sousa et al., 2004; Lowy, 2003).

Staphylococcal infection manifests as boils with discharge containing microbes (alive and dead), neutrophils, necrotic tissue, lysed host material, and bacterial cells. Normally, hosts with healthy immune systems are able to clear the disease and drain the ulcer.

However, in immunocompromised individuals or even healthy people on occasion, the infection can spread to deeper tissues and become an intrusive, potentially fatal, infection (Norvick, 2006). As Bowersox (1999) points out, it frequently causes infections in surgical wounds and is thus one of the top five nosocomial infections.

Dogs, cats, rabbits, stallions, steers, and pigs are only some of the animals that S. aureus can infect and colonise (Morgan, 2008). An important worry is the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in swine and other domesticated animals, which can serve as reservoirs for the colonisation of humans; an example of this is pigs infected with MRSA ST398 (Weese, 2010).

A variety of S. aureus strains that are safe to use with medication have emerged as a result of the overuse of antibiotics (Lowy, 1998). The introduction of penicillin in the 1940s as a treatment for Staphylococcus aureus infections significantly reduced mortality and misery. The close proximity of penicillinase, however, led to the development of resistance in the late 1940s (Eickhoff, 1972).

Staphylococci have evolved remarkable resistance to common antibiotics as erythromycin (Walmark & Finland, 1961), ampicillin (Klein and Finland, 1963), and others (Eickhoff, 1972). The rapid transmission of microbes resistant to antimicrobial treatments is often represented by traits encoded on plasmids (Morris et al., 1998).

The persistence of S. aureus in disease is due, in part, to the fact that it has a tendency to become completely resistant to antibiotics (Waldvogel, 2000). Nosocomial infections caused by Staphylococcus aureus are becoming more of a concern for healthcare providers due to the increasing number of patients seen outside of traditional hospital settings (CDC NNIS System, 2001; Diekema, 2001).

The discovery of anti-infective drugs more than seventy years ago ushered in a new era of medicine development and its application in human and animal health and horticulture.

These discoveries were potent and thought to be successful against harmful microbes, but their success was short-lived since, in every instance, resistant microbes emerged (D’Costa et al., 2011).

The increasing prevalence of antibiotic resistance is one of the most intractable problems faced by human services organisations worldwide. The persistent decline in the number of new experts (antimicrobials) joining clinical practice is exacerbating this problem, which is widely seen as a significant threat to public health (D.H., 2000).

The prospect that infections caused by microbes that are resistant to antimicrobial agents may take longer to treat effectively and that previously manageable infections are becoming more difficult to treat is a growing concern (Butler et al., 2006).

Despite the fact that the public and healthcare administrators have taken notice of the problem of multidrug resistance, the incidence of bacteria and viruses that are resistant to antibiotics has grown dramatically over the past decade, particularly in healthcare facilities and hospitals (NNIS, 2001).

1.2 Statement Of The Problem

Cattle are mostly raised in Nigeria for their meat. It has been suggested that the nares and skin of both humans and animals provide an ecological niche for S. aureus colonisation.

However, this colonisation does not always lead to infection, thus classifying the bacterium as a normal flora of these areas (Kuehnert et al., 2006; Lowy, 1998, 2003; Onanuga & Temedie, 2011; Vandenbergh & Verbrugh, 1999; Williams, 1963).

The nares and skin are normal habitats for S. aureus, but any damage to these areas might allow the bacteria to spread to other parts of the body or even the bloodstream, leading to infections.

Opportunistic (staphylococcal) infections are the name given to these types of illnesses. Staphylococcus aureus is more likely to develop resistance to antibiotics than other types of bacteria (Weese, 2010).

Methicillin and vancomycin are the first lines of defence against methicillin-resistant Staphylococcus aureus (MRSA), but this fact, along with the ongoing misuse of medications and the lack of regulation over antibiotic sales, is making the problem worse.

The possibility that methicillin-resistant Staphylococcus aureus (a multidrug-resistant organism) is transmitted from animals to humans has been suggested by several studies, including those by Cuny et al. (2015), Fluit (2012), Johnson (2011), and Morgan (2008).

Because these animals are often asymptomatic carriers, consumers, butchers, retailers/handlers of beef, and cattle herders are all at risk when multidrug-resistant Staphylococcus aureus is present in their noses. T

his study aims to assess the frequency of S. aureus bacteria linked to MRSA in livestock and provide recommendations for managing infections caused by these bacteria.

1.3 The Purpose of the Research

The overarching goals of the research were to

1. determine the frequency of MRSA in animals and
2. use the antibiogram of the isolates to propose strategies for preventing staphylococcal infections in humans. Here are the specific goals:
3. isolate and identify S. aureus from nasal passage of healthy cattle by Gramme staining and biochemical tests (catalase test, slide coagulase test and fermentation of mannitol);
4.  Determine the antibiogram of the isolates and calculate the Multiple Antibiotic Resistance Index (M.A.R.I) using the antibiogram of the isolates; determine the minimum inhibitory concentration (μg/disc) of the S. aureus isolates to vancomycin;
5.  Determine the minimum inhibitory concentration (μg/ml) of the isolates to flucloxacillin as a test for methicillin resistant S. aureus (MRSA) and vancomycin and
6.  Determine the synergistic, antagonistic or additive effect of two antibiotics to suggest possible control of staphylococcal infections in human caused by multidrug resistant livestock associated S. aureus.

1.4 Research Questions

1. Is it possible to isolate and identify Staphylococcus aureus from the nasal passages of healthy cattle?
2. Once the antibiogram of a S. aureus sample has been determined, how does one go about calculating the Multiple Antibiotic Resistance Index (MARI) for the same isolate?
3. How does one find the lowest concentration of S. aureus that inhibits growth (μg/disc)?
4. What is the procedure for determining the minimum inhibitory concentration (μg/ml) of flucloxacillin and vancomycin against Staphylococcus aureus that is isolated from the nasal passage of healthy cattle?
5. Should we expect additive, antagonistic, or synergistic effects from the combination antibiotics?

1.5 significance Of The Study

There may be a greater emphasis on the risk of MRSA in ruminant flocks as a consequence of this finding. This finding has the potential to inform the public about the consequences of undercooked beef and the neglect of multidrug-resistant Staphylococcus aureus in livestock. Findings may point to ways to reduce the spread of staphylococcal infections in people that originate in livestock.

1.6 The justification of the study

Researchers hope that by updating our knowledge of multidrug-resistant Staphylococcus aureus, this work can help in the fight against staphylococcal infections in humans that are linked to animals.