eChapters

Salmonella consists of bacilli leading to Enteric fever, Gastroenteritis, Speticaemia etc. The important member of the genus is Salmonella typhi, which causes Typhoid fever. Salmonella are of two groups;
(i) Enteric fever group consisting of typhoid & Paratyphoid bacilli exclusively or primary human parasites
(ii) Food poisoning group, which are animal parasite but may infect humans causing gastrointestinal infections Salmonella is oxidase negative, catalase positive, indole and Voges Proskauer (VP) negative, methyl red and Simmons citrate positive, H₂S producing andurea negative.
Characteristics
Cells are rod-shaped, non-spore-forming, and predominantly motile by means of peritrichous flagella with diameters of around 0.7-1.5μm and lengths of 2-5μm with a few exceptions. On blood agar, colonies are 2-3mm in diameter. Colonies are generally lactose non-fermenters. They obtain their energy from oxidation and reduction reactions using organic sources, and are facultative anaerobes. They produce acid from glucose usually with the production of gas, and are oxidase negative. Most produce hydrogen sulphide except Salmonella paratyphi A and Salmonella typhi, which is a weak producer. They are identified
with a combination of serological and biochemical tests. Salmonella species are classified and identified into serotypes according to the White-Kauffmann-Le Minor scheme; there are more than 2,500 Salmonella
serotypes that have been described and reported.

It is a must for the research scholars to attend scientific conferences of the Parasitology associations, after being members. It is advisable to become life-members of all three Parasitology associations, in India i.e. Indian Society of Parasitology, Lucknow, Indian Association for Advancement of Veterinary Parasitology, IVRI, Izatnagar and Indian Academy of Tropical Parasitology, JIPMER, Pondicherry. The annual conferences expose better chances to interlink with Parasitologists of the country and at times foreign scientists.

It is always advantageous if there is a senior scientist,a mentor or a Guru ( I have not used the term teacher as all may be teachers but may not be Guru as per Indian mythology) who can recognize your talents and may believe that you may achieve some unusual goals, if properly guided or encouraged. This is important for carrying an important task to its fruitful results. Here what we are referring a Guru is not in the sense as is presently used for searching a god father. There is a vast difference between the two. The perception about god-father is that he may not possess the required knowledge but is perfect in manipulating situations in his favor so that work is done by all means. In scientific world, this is mostly applied to the persons who have contact with higher ups helping in getting promotions or foreign trips. These god fathers are good only to provide some material gifts but are not best in their scientific achievements hence cannot replace a Guru or a good scientist.

When you are assigned with your thesis problem or some problem is puzzling you, the first step is to search the related literature ; here the term literature is used not as it is used in humanities but this means the literature related to the research work published by the earlier scientists on the topic. The searching of literature is a most important and first step in conducting research on a particular topic. This not only acquaint you with the work of other scientists who tried to solve the problem but also confirms the possibility that previous scientists might have solved that problem and yours will be a repeat attempt ; in that case you may tackle other aspects of the problem, if at all they are existing and important in present circumstances.

This chapter deals with the principles and applications of serological tests used to detect antigens and antibodies. It distinguishes primary, secondary and tertiary binding tests and explains antibody titre, affinity, avidity, sensitivity and specificity. Important techniques include precipitation, agglutination, complement fixation, neutralization, immunofluorescence, ELISA, radioimmunoassay, Western blotting and the radioallergosorbent test. The chapter also addresses serum decomplementation and the interpretation of positive and negative reactions. These methods are central to the laboratory diagnosis, surveillance and control of infectious diseases. The objective questions enable readers to compare diagnostic techniques and select appropriate tests according to their principles, applications and analytical performance.

A. Answer the following.

Q.1.     What are the different enzymes used to couple with antibodies to prepare conjugates for use in ELISA?
Ans.     HRPO, Alkaline phosphate, b galactosidase, penicillinase etc.

Q.2.     What does it indicate if any woman has HI titre of > 10 for rubella ?
Ans.     It means that the woman is immune to rubella. If it is less than 10 it indicates that the woman needs to be immunized against rubella.

Members of the genus Serpulina (Treponema) are host-associated spirochaetes found in the oral cavity, intestinal tract and genital region of animals and humans. The cells are wider, are not as tightly coiled as th e leptospires and can be stained by aniline dyes.
The species of veterinary significance are S. Hyodysenleriae (swine dysentery) and T. paraluiscunicllii (ventdisease of rabbits). S. innocens, present in the faecesof pigs and dogs, is thought to be non- athogenic,although some workers regard S. innocens as a strainof S. hyodysenteriae of lower virulence. S. hyodysenteriae and S. innocens are s imilarmorphologically, culturally as well as biochemicallyand can be grown on laboratory media. T. Paraluiscuniculi has not been cultured in vitro.
Normal Habitat
T. paraluiscliniculi produces a benign venereal disease of rabbits and is present in lesions in the genito-perineal area of rabbits. It causes latentin fection in mice, guinea- pigs and hamsters. The treponemes can be found in the lymph nodes of these animals. The reservoir of S. hyodysenteriae is the intestinal tract of pigs, wild rats and mice. Recovered, asymptomatic pigs can excrete these organisms in faeces for 3 months or more. Survival of S. hyodysenteriae in soil or voided pig faeces is short, about 24 48 hours. Infection is by the faecal-oral route.

Introduction
Antibiotic-resistant E. coli develops as a result of the heavy use of antibiotics in the production of food animals, which is then found in the meat from those animals. There have been reports of a number of antimicrobial resistant E. coli infections linked to the ingestion of tainted milk and chevon. As a result, the existence of antibiotic resistant E. coli is a significant and expanding global public health risk. Escherichia coli of animal origin has also been seen to colonise humans, and because it is resistant to many conventional antibiotics, it can cause serious illnesses for which there are few effective treatment choices. Due to its ubiquitous presence in the environment, E. coli has traditionally been recognised as the main vehicle for the transmission of various antibiotic resistance genes and vectors.Extended-spectrum beta-lactamases (ESBLs), which can make the bacteria resistant to some frequently used antimicrobial treatments, are tiny proteins (enzymes) that some strains of E. coli have been shown to manufacture under favourable conditions. A major issue around the world is the emergence of different E. coli strains that produce ESBL in foods that come from animals that are raised for food. The ESBL enzymes TEM, SHV, and CTX-M from Group A have been widely reported to be generated by E. coli and have been shown to hydrolyze ampicillin, carbenicillin, oxacillin, and an extended spectrum of cephalosporins, including ceftazidime and cefotaxime.
Extended beta spectrum lactamase producing E. coli
The occurrence of antimicrobial resistance and the presence of corresponding resistance genes in the environment is an ancient phenomenon. This is largely due to the fact that many of today’s antimicrobial agents are derived from natural precursors produced by soil bacteria such as Streptomyces. These natural compounds likely evolved to mediate microbial competition for

Small ruminants is a composite term used for sheep and goats. Throughout the developing countries, small ruminants make a very valuable contribution, especially to the poor in the rural areas. These contributions range from precious animal proteins (meat and milk) to fibre and skins, draught power in the highlands, food security and stable households. By and large, the importance and extent of the contributions are inadequately understood as a consequence of which these valuable genetic resources continue to be generally neglected. Research and development investments to improve the relatively low level of contribution do not match their potential importance, the contribution to nutritional security and livelihoods of the poor in rural areas. Species like goat and sheep are of short-generation interval, have a high prolificacy rate and require less land, investment and operational expenses and are better suited to the resource endowment of the poor.

I. Definition

Solute transport in plants, translocation, primarily occurs in the phloem, but it can occur in the xylem.

II. Solute Transport in the Xylem

Some solutes are transported in the xylem

Water and dissolved ions are the main substances in vessels/tracheids

These materials are transported via transpiration stream

Xylem sap may also contain organic materials, usually in relatively low concentration (with a notable exception being maple sap in the spring which is comprised of 2% or more sucrose).

Substances move at different rates depending on matrix effects, metabolic needs, etc.

The order Spirochaetales contains two families, Leptospiraceae and Spirochaetaceae. It comprises spiral or helical bacteria (spirochaetes) which share some unique morphological and functional features. Members of the order are motile by means of endoflagella which are located within the periplasm.
The spirochactes are slender, motile, flexuous, unicellular, helically coiled bacteria ranging rrom 0.1 -3.0 μm in width. The outer sheath, the outermost layer of a spirochaete cell, is a multi layered membrane that completely surrounds the peri plasmic flagella (axial filament) and the helical protoplasmic cylinder. The cylinder consists or the nuclear material, cytoplasm, cytoplasmic membraneand the peptidoglycan portion of the cell wall.
The periplasmic flagella are wrapped around the cylinder and are in the peri plasmic space of these Gram-negative bacteria. One end of each flagellum is inserted near a pole of the protoplasmic cylinder and attached by platelike structures called insertion discs. The distal end of each flagellum is not inserted and extends to the centre of the cell and may overlap the flagellum from the opposite end. The periplasmic flagella facilitate the motility of the bacteria in viscid environments.
Leptospira species
Members of this species (leptospires) are motile helical bacteria (0.1 x 6 to 12 μm) with hook-shaped ends. Although cytochemically Gram-negative, they do not stain well with conventional bacteriological dyes and are usually visualized using dark-field microscopy. Silver impregnation and immunological staining techniques are used to demonstrate leptospires in tissues. Leptospirosis, which can affect all domestic animals and humans, ranges in severity from mild infections of the urinary or genital systems to serious systemic disease.

Generally microorganisms are so small and colourless in their natural state that it becomes difficult to observe them clearly under microscope. Stains and dyes, which are colouring agents, are used by biologist for better understanding of the morphological and anatomical structures of the organisms under study. Stains are prepared with great care and specification to get satisfactory result, while dyes are not as exacting in their characteristics.

Dyes are of two types, natural and synthetic. The natural dyes are used for histological purposes, whereas the synthetic dyes for bacterial stain. Usually dyes which are derivatives of cyclic compound benzene of benzole, are prepared from one or more substances found in coal-tar, and so are called coal-tar dyes. Chemically dyes are organic compounds containing both chromophore and auxochrome groups linked to benzene rings. Chromophore group provides the compounds the property of colour and thus benzene containing chromophores are called chromogens. It has no affinity to combine with fibres or tissue and as such not called dye. For being a dye, compound should contain an auxillary group which provides the compounds the properties of electrolytic dissociation.

The dyes may be acidic, basic or neutral. The acidic dyes are eosin, acid fuchsine and picric acid whereas the basic dyes are safranin, methylene blue, crystal violet etc. The acidic dyes ionize to give the dye portion of molecule a negative electrical charge. They are salts of sodium, potassium, calcium, magnesium etc. The basic dyes ionize to give the dye portion of molecule a positive electrical charge and are salts of chlorides, sulphates or acetates.

First discovered by Scottish surgeon sir Alexander ogston (1880) in infected tissues. He named it as staphylococcus” (Greek staphyle, bunch of grapes;
KOKKAS, berry).
Systematics
Domain : Bacteria
Phylum : Firmicutes
Class : Bacilli
Order : Bacillales
Family : Staphylococcaceae
Genus : Staphylococcus
Species : Staph. aureus
Staph. Intermedius
Staph. hyicus
Habitat and Ecology
Staphylococcus occurs worldwide in mammals although the spread of staphylococcal strains between different animal species is limited. They colonise the nasal cavity, skin and mucous membranes and can be transient in the intestinal tract. It is an opportunist type organism.

Introduction
Sterilization of culture media, containers, and instruments is crucial in bacteriological work to ensure the isolation and maintenance of pure cultures. Sterilization and sanitization are essential processes in a microbiology lab to prevent contamination and ensure accurate results. Sterilization refers to the complete elimination of all microorganisms, including bacteria, fungi, viruses, and spores, using methods like autoclaving, dry heat, filtration, and chemical agents. Sanitization, on the other hand, reduces microbial load to a safe level through cleaning and disinfection using alcohols, detergents, and UV light. These practices maintain aseptic conditions, protect lab personnel, and preserve sample integrity. Proper sterilization and sanitization are fundamental to microbiological research, clinical diagnostics, and industrial applications, ensuring reliable and reproducible experimental outcomes.
Preparations for Sterilization Before sterilization, cleaned and dried test tubes and flasks should be carefully plugged with clean, non-absorbent cotton. Pipettes should also be plugged at
the mouth end, and the plugs should remain in place during use to minimize oral contamination. Cotton plugs provide sufficient ventilation for bacterial growth while preventing external contamination.

Introduction
AMR is a critical global problem that affects human, environmental, and animal health. AMR is a complex problem; it is necessary to look at it from different disciplines to frame it within the One Health approach [Shrestha,2018].The World Health Organization (WHO) has identified AMR as a top ten global public health threat.Globally, there were an estimated 4.95 million deaths associated with bacterial AMR in 2019, including 1.27 million deaths attributable to bacterial AMR [O’Neill, J. (2016)]. The economic impact is equally alarming. The World Bank projects that AMR could lead to an additional US$ 1 trillion in healthcare costs by 2050, and over US$ 1 trillion in annual gross domestic product (GDP) losses by 2030.The One Health approach is defined as a joint effort of various disciplines that come together to provide solutions for human, animal, and environmental health. AMR is linked to each of these three components due to the irresponsible and excessive use of antimicrobials in various sectors (agriculture, cattle raising, and human medicine). Under the pressure of antimicrobial selection, bacteria acquire resistance genes and mobile genetic elements that can spread to other bacteria of the same or different genus. When bacteria acquire resistance to antimicrobials, they also acquire a greater ability to proliferate in animals, humans, and the natural world. Mismanagement of antimicrobials, inadequate infection control, agricultural debris, contaminants in the environment, and migration of people and animals infected with resistant bacteria facilitate the spread of resistance [Collignon,et.,al,2018]. AMR represents a global public health problem, for which epidemiological surveillance systems have been established, aiming to promote collaborations directed at the well-being of human and ani mal health and the balance of the ecosystem. Several international organizations (The World Organisation for Animal Health [OIE], WHO, and the Food and Agriculture Organization of the United Nations [FAO]) have joined forces to develop a Global Action Plan on Antimicrobial Resistance-WHO. Action taken in this plan included understanding the AMR from surveillance and research. The advisory group established guidelines for AMR surveillance to ensure all countries implement integrated surveillance, which will cover the use and consumption of antimicrobials in the human and animal population. These guide lines will provide a clear understanding of how AMR spreads in different settings and specific areas. It will allow to study the correlation between AMR and antimicrobial use in a different setting (animals, humans, and environment) and to assess the effect of interventions within and between sectors [W.H.O 2015,2017].

Systematics
Domain : Bacteria
Phylum : Firmicutes
Class : Bacilli
Order : Lactobacillales
Family : Streptococcaceae
Genus : Streptococcus
Species : Str. agalactiae, Str.dysgalactiae, Str. equi subsp. zooepidemicus, Str.
uberis, Str. equi subsp equi, Str.suis, Str. canis, Str. pyogenes (human)
History
Rivolta (1873) described chain forming organisms in pus from a case of strangles in horses. In 1878-79, Pasteur recognized this organism as a pusforming agent. In 1903, Hugo Schottmuller introduced blood to differentiate various types of hemolysis. In 1928, Rebecca Lancefield reported a serological method of grouping Streptococci.
Habitat
Streptococci are worldwide in distribution. Most of the Streptococci of Veterinary interest live as commensals in the mucosa of the upper respiratory and lower urogenital tracts. They do not survive for long away from the animalhosts.