Poultry is one of the most important sectors in agriculture industry of Pakistan 1 contributing about 11.9% in gross domestic product (GDP) of Pakistan and about 55.4% in year 2016-17 in the agriculture sector as a rapidly growing sector 2. Poultry industry is a big source of human food in the form of meat and eggs 3.

Egg is considered as a sole source of essential nutrients and it carries majority of proteins vital to human health. In spite of essential part in diet, different bacteria are found in eggs as a contamination or in-ovo transfer such as Salmonella species, Listeria monocytogens, Camphylobacterjejuni, Staphylococcus aureus and E. coli4. The majority of the marketable eggs are sterile and the yolk is delimited by albumen which has high water content, flexibility and shock absorbing ability. The outer surface of the shell is cuticle which consists of a mucous coating deposited just before laying. This cuticle layer aids to protect the internal substances of the egg from bacterial access through the shell 5.

Microorganisms are the major cause of food borne diseases in human that occur by consuming unhealthy products from poultry and other sources. Among all microbes, bacteria are the most common organism to cause illness 6. Campylobacter is most commonly found bacteria in poultry products like eggs and meat. It is the main cause of gastroenteritis in humans. It is horizontally transmitted via infected livestock and free-living animals 7. Microbes depreciate the quality of eggs, impairs growth and decreases the performance of birds 8. Egg containing Salmonella can cause food poisoning although it appears normal. In this way, egg is used as a vector by these microbes in causing illness to humans 9.

Immunity is the capacity of the body to resist the invading organisms. Immunity works by the immunoglobulins and white blood cells. Immunity of chicks may be modified by active or passive immunity 10. In poultry industries, different kind of vaccines and antibiotics are being given to animals to increase growth and food production. These drugs may reside in their body for a prolonged time. Thus, the present study was designed to investigate chicken egg samples obtained from different areas of district Faisalabad to isolate and identify the bacteria through morphological and biochemical tests and then through antibiotic sensitivity evaluation to sort out which bacterial species are resistant to commonly used drugs including; penicillin, cefotaxime, tetracycline, gentamicin and levofloxacin in poultry sector.

Various biochemical tests were used for identification of microorganisms including: Indole test, Methyl red test, Voges- Proskauer test, Citrate utilization test, Catalase test, Starch Hydrolysis test, Triple Sugar Iron agar test, Urease test, Coagulase test, Sugar Fermentation test e.g., Glucose, Mannitol, Fructose etc. 1213.

Bacteria from nutrient agar (general purpose media) were streaked on MacConkey’s agar, Eosin methylene blue agar, Staphylococcus 110 agar and Salmonella-Shigella agar as shown in Figure 2. Then, biochemical tests were applied for further confirmation of identification. The results are displayed in Table 1. Whereas, glucose, lactose and sucrose fermentation abilities of these bacteria were shown in Figure 3. The result of triple sugar iron fermentation to differentiate between fermenting and non-fermenting bacteria with the ability of acid production from fermentation is displayed in Table 2. Resistance and sensitivity profile of various bacterial isolates against different drugs has been shown in Table 3. Zone of inhibition of various bacterial isolates using different antibiotic disks have been shown in Figure 4.

Poultry is known to be the oldest on earth. It is known for over 150 million years. Poultry species include ducks, geese, turkeys, pheasants, pigeons, peafowl, guinea fowl and chickens. Poultry is important in providing food and fiber to humans in the form of eggs and meat. Among all poultry species chicken is the most commonly used specie for human food consumption. The commercial chicken is the largest industry that provides with eggs and meat 15. Globally, the production of poultry products like eggs and meat is rapidly increasing. This reflects that the consumption of these products has also been increased. According to different researches an overall consumption of poultry products from 1995 to 2005 has increased globally with the ratio of 53% for chicken meat, 13% for turkey meat, 67% for duck meat, 53% for goose meat, 39% for chicken eggs and 27% for other eggs. Therefore, it is important to know that what types of contaminants may be present in these products and what risks they can cause to human health 16. Microbes depreciate the quality of eggs, impairs growth and decreases the performance of birds 8.

Antibiotic resistance is a natural phenomenon. Data regarding the prevalence of antibiotic resistance and the types of ESBLs produced by E. coli are available for certain regions of China and from many other countries 1718. In a study conducted in China, ninety-seven percent of the E. coli isolates were resistant to at least three different classes of antibiotics (MDR), whereas 18% were resistant to all antimicrobials tested 1819. Isolation, identification and characterization of commonly occurring egg borne pathogens including E. coli, Salmonella entritidis, Bacillus subtilis, Staphylococcus aureus was carried out by different cultural, morphological and biochemical tests. For culturing these microbes different culture media were used that include: Nutrient agar, Salmonella-shigella agar, MacConkey agar, Eosin-methylene blue agar. Antibiotic resistance pattern of recovered bacterial pathogens were determined by disk diffusion method (Kirby-Bauer). Zone of inhibition was measured through vernier calliper. Data was analyzed by Analysis of variance. The results revealed a high prevalence of Salmonella entitidis with 40.83% following Staphylococcus aureus with 22.08%, Escherichia coli with 17.92% and Bacillus subtilis in a lower ratio with 2.5%. This showed that Bacillus subtilis is present in a very low amount in chicken egg. The antibiotic sensitivity test showed different resistance patterns of the isolated microbes. Bacillus subtilis was highly resistant to penicillin and cefotaxime while it sensitivity for gentamicin, tetracycline and levofloxacin. E. coli was sensitive to gentamicine and levofloxacine while it showed resistance to other three antibiotics that were tetracycline, cefotaxime and penicillin. Staphylococcus aureus was sensitive to different drugs naming penicillin, gentamicin, tetracycline and levofloxacine. The only drug to which Staphylococcus aureus showed resistance was cefotaxime. Salmonella was resistant to tetracycline and gentamicin. Thus, proper attention should be paid to cope up with possible future egg-borne illnesses as in present study chicken eggs have been found contaminated with different pathogenic or non-pathogenic bacterias.