eChapters

A. Evaluation of the efficacy and resistance of anthelmintics against Helminths Anthelmintic resistance According to WAAVP (World Association for the Advancement of Veterinary Parasitology) anthelmintic resistance is a failure to reduce feacal nematode egg count by at least 95%. Technically accurate definition is that resistance is a genetically determine decline in the efficacy of an anthelmintic against a population of parasite that is susceptible to the drug. The history of parasite resistance to anthelmintic starts with the first report on phenothiazine resistance in 1957. Haemonchus contortus was the first nematode to develop resistance against different anthelmintic. The World Association for the Advancement of Veterinary Parasitology has recommended two tests for detecting anthelmintic resistance in ruminants, horses and pigs. These are in vivo test (FECRT) and an in vitro test (the egg hatch test). Detection Technique

Genetics is the study of what genes are, how they carry information, how their information is expressed, and how they are replicated and passed to subsequent generations or other organisms.

DNA in cells exists as a double-stranded helix; the two strands are held together by hydrogen bonds between specific nitrogenous base pairs: A-T and C-G.

A gene is a segment of DNA, a sequence of nucleotides, that code for a functional product, usually a protein.

When a gene is expressed, DNA is transcribed to produce RNA; mRNA is then translated into proteins. This is also referred as Central Dogma of Life. The DNA in a cell is replicated before the cell divides, so each daughter cell receives the same genetic information.

The term growth for bacteria and other microorganism usually refers to changes in the total population rather than an increase in size or mass of an individual organism. As the mechanism of conservation and dissipation of heat generated during metabolism lacks in bacteria, the enzyme system in bacteria gets directly influenced by temperature. The purpose of studying the bacterial growth curve is a) to become familiar with the population growth dynamics of bacterial culture and b) to plot a growth curve and determine the generation time of bacterial culture.

A number of methods are now available for measuring bacterial growth. Some important ones are

1)By colony counting or cell counting

2)By weighing the cells

3)By cell activity (turbidity method)

The essential nutrients and their function in microbial cells

A. Enumeration of Different Microflora of Soil
Introduction
Agriculturally, soil is the region which supports the plant life by providing mechanical support and nutrients required for growth. From the microbiologist view point, soil is one of the most dynamic sites of biological interactions in the nature. Soil is an admixture of five major components viz. organic matter, mineral matter, soil-air, soil water and soil microorganisms/living organisms. The amount/ proposition of these components varies with locality and climate.

The soil organisms are broadly classified in two group’s viz. soil flora and soil fauna, the detailed classification of which is as follows.
1) Soil flora
a) Microflora Bacteria, Fungi, Molds, Yeast, Mushroom, Actinomycetes, Streptomyces, Algae e.g. BGA, Yellow Green algae, Golden brown algae.
b) Macroflora

The science dealing with the measurement of size of any microscopically visible microorganism is known as micrometry which is based on the principle of physics. Before measuring a cell, the diameter of the microscopic field must be established by means of optic devices, namely an ocular micrometer and a stage micrometer.

a)Ocular micrometer : It is a circular disc that is placed in the eyepiece. The disc is graduated in to several small divisions marked from 0 to 100.It is placed inside the eyepiece of the microscope. The distance varies according to the objective of the microscope which can be easily determined by using a stage micrometer.

b)Stage micrometer : It is a glass slide graduated in 1 mm. Again 1mm is divided into 10 large divisions and 100 small divisions (10 x 10 = 100 divisions). These divisions are equally placed therefore 1 small division is equal to 0.01 mm or 10 μm.

Microscope is the primary instrument of a microbiology laboratory and it produces enlarged images of small objects which are invisible by naked eye. With a microscope the operator can get a close view of minute structures which helps in examination and analysis. Examination of minute objects with a microscope is called ‘microscopy’. In microbiology, measurement of the microbial dimension observed under microscope is known as ‘micrometry’.

Types of microscopes

There are two types of microscopes i.e. light / optical and electron microscope depending on the sources of energy to create the image. The optical microscopes use the lenses and light (artificial or sunlight) to make an image. Following types of optical microscopes are available.

PLANT NUTRITION

Plants use inorganic minerals for nutrition, whether grown in the field or in a container. Complex interactions involving weathering of rock minerals, decaying organic matter, animals, and microbes take place to form inorganic minerals in soil. Roots absorb mineral nutrients as ions in soil water. Many factors influence nutrient uptake for plants. Ions can be readily available to roots or could be “tied up” by other elements or the soil itself. Soil too high in pH (alkaline) or too low (acid) makes minerals unavailable to plants.

A. Answer the following.

Q.1.     What is the full form of the followings : MALT, GALT and BALT
Ans.    MALT : Mucosa associated lymphoid tissue ; GALT : Gut associated lymphoid tissue ; BALT : Bronchus associated lymphoid tissue

Q.2     What is the definition of antigen ?
Ans.    Antigen is any agent capable of binding specifically to components of the immune response such as lymphocytes and antibodies.

Q.3.     What is the definition of immunogen ?
Ans.    Immunogen is any agent capable of inducing an immune response.

NEW CELLS ARE PRODUCED BY DIVISION OF PREVIOUSLY EXISTING CELLS

All cells come from previously existing cells

To make a new cell identical to itself a cell must perform 4 tasks:

It must grow and make additional copies of all its organelles, enzymes, etc..

It must duplicate its DNA

It must accurately separate the DNA into 2 units, so that each cell gets a full set

It must divide into 2 cells (cytokinesis)

Fermentation

The term fermentation is loosely used to denote any process in which microorganisms are involved, regards of whether or not the organism is growing in the presence of molecular oxygen. Thus, it can be defined as 'an ATP generating metabolic process in which organic compounds serve both as electron donor (becoming oxidized) and electron acceptor(becoming reduced). Energetically, fermentations are poor energy yielding process and products have lower energy content then the substrates. Since there is no net oxidation in fermentation, the number of molecules of C, H and O remain the same in products as in the substrate.

Antimicrobial resistance (AMR) is a mounting global health emergency that threatens the effectiveness of modern medicine and veterinary care. In India, the challenge is compounded by high antibiotic consumption, unregulated access to antimicrobials, and widespread use in agriculture and animal husbandry. The World Health Organization has identified the Eskape pathogens— Enterococcus faecium, Staphylococcus aureus, Klebsiellapneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp, as priority organisms due to their ability to “escape” the effects of antibiotics and cause life-threatening infections. Simultaneously, zoonotic transmission of resistant bacteria from animals to humans is emerging as a critical concern, particularly in regions with close human-animal interfaces like Jammu & Kashmir. The importance of Eskape pathogens to the establishment and promotion of antimicrobial resistance in hospitalized patients was first recognized in a 2008 by Rice. The morbidity and mortality associated with Gram-negative Eskape pathogens is particularly concerning, as new antimicrobial agentsthose with activity against multidrug-resistant and pan-resistant Gram-negative strainshave not emerged as quickly as needed. Consequently, nosocomial infections continue to pose a serious threat to patient health, especially among critically ill inpatients and those undergoing invasive procedures or requiring the placement of medical devices. Eskape pathogens are well known for their intricate resistance mechanisms, often leaving clinicians with limited therapeutic options. Due to their significant role in driving antimicrobial resistance within hospital settings, consistent and systematic monitoring of their resistance profiles is crucial for guiding effective infection control and therapeutic strategies.This also serves as a critical indicator of regional resistance trends among hospitalized populations. In animal sector, the wastewater of livestock slaughterhouses, animal products (raw or processed) have been considered a source of multidrugresistant bacteria with clinical implications as well as their dissemination into the environment and entry into human food chain.Bacteria from the livestock can act as opportunistic pathogens and carry resistance genes that are important for both veterinary and human health. Since many antibiotics are used in both human and animal health fields, the resistant bacteria enter the environmentespecially through wastewater treatment plants affected by slaughterhouse wasteposing risks to public health. Among the various sources, the water used during poultry slaughtering often contains multidrug-resistant bacteria and can expose slaughterhouse workers to infection. To reduce these risks, it’s important to develop strategies that limit bacterial release into the water systems and prevent their spread to people and the environment. The development of AMR has been attributed to several factors comprising of microbial mutations rendering the antibiotics ineffective, human interference such as over use and over-prescription of antimicrobials, agricultural and commercial application of antimicrobials in the animal sector, and human behavioural factors (Vijayalaxmi et al., 2021). An expected annual rise of antimicrobial resistance (AMR) by 5–10 % annually has been predicted by the Indian Council of Medical Research (ICMR) Annual Report 2021 due to wide spread abusive use of broad-spectrum antibiotics (ICMR Annual Report 2021). Twelve families of priority drug-resistant bacteria (critical, high and medium) posing great threat to human health in terms of resistance to selected antimicrobials have been identified in priority pathogen list (PPL) of Global Action Plan, World Health Organisation (WHO) to stimulate the research towards the development of new antimicrobials against a particular drug-resistance (WHO,2017). From the Indian perspective, AMR is a grave concern as the Indian population is the highest consumer of antibiotics in the world (10.7 units per person). The poor public health systems, hospital infections, high rate of infectious diseases, easy availability of inexpensive

Moraxella bovis occurs as short (1.0 to 1.5 x 1.5 to 2.5 μm), plump Gramnegative rods or, occasionally, cocci which typically occur in pairs. This organism is non-motile, aerobic and usually catalase-positive and oxidasepositive. Although proteolytic, it is unable to utilize sugars. Growth, which is enhanced by the addition of blood or serum to media, does not occur on MacConkey agar. The optimal temperature for growth is 33-35°C. Most M.phenylpyruvica strains will grow on MacConkey agar. But M.bovis and M.lacunata are unable to do so.
Virulent strains, when isolated from cases of infectious bovine keratoconjunctivitis, are fimbriate, haemolytic and grow into the agar. Species, other than M.bovis, which are periodically isolated from clinical specimens, are generally regarded as non-pathogenic.
Usual Habitat
Moraxella bovis is found on mucous membranes of carrier cattle. The organism is susceptible to desiccation and is short-lived in the environment. It can survive for up to 72 hours in the salivary organs and on the body surface of flies, which can act as vectors.
Colonial Appearance
On blood agar after 48 hours’ incubation the colonies of M.bovis are flat, round, small (1 mm diameter), greyish-white and friable, surrounded by a narrow zone of complete haemolysis. The appearance is not unlike that of a beta-haemolytic streptococcus. New isolates are often piliated and erode the agar, sinking into it. Colonial growths will autoagglutinate when suspended in saline. On subculture, colonial variation is common, pili are no longer formed and the colonies are butyrous and less likely to autoagglutinate. Some colonies can become non-haemolytic. The strains of M. hovis (M.equi) isolated from
horses are non-haemolytic even on primary isolation. M.lacunata and M. phenylpyruvica are non-haemolytic on blood agar and some strains of M. phenylpyruvica will grow on MacConkey agar.

A. Morphological Examination of Bacterial Samples
Introduction
Bacteria are most widely distributed, the simplest in morphology, the smallest in size and difficult to identify. They are prokaryotic and a few are photosynthetic. Most bacteria are only 0.5 to 2.0 μm in diameter. Bacteria are generally rod, spherical or curved shaped. Rod shaped bacteria may vary considerably in length, have square round or pointed ends and may be motile or non-motile. The spherical or coccus shaped bacteria may occur single, in pairs in tetrads, in chains or in regular masses. The helical and curved shaped bacteria exist as slender spirochetes, spirillum and bent rods (vibrios). In this exercise the ubiquitousness of these organisms will be demonstrated in the air and water, on body and in mouth etc.
Materials
1. Petri plates containing nutrient agar
2. Sterile cotton swabs
3. Sterile water blank
4. Tube of nutrient broth
5. Materials for simple staining

1. Morphology of Bacteria
Structure of Bacteria
Bacteria are very small with a diameter of 0.5 – 1 μm in size. Due to this small size the surface area / volume ratio is very high compared to that of large organisms of similar shape. The large surface area compared to a small volume facilitates easy nourishment of all areas of the cell. So there is no circulatory mechanism to distribute the nutrients and there is little or no cytoplasmic movement within the cell.
i) Shape
Bacteria exhibit three types of morphology;
• Spherical - cocci (coccus) - Greek word kokkos, meaning a berry
• Straight rods - bacilli (bacillus) - Latin word bacillus, meaning a stick
• Helically curved rods -spirilla (spirillum)
Variations in these basic forms are also seen. Eg: cocobacillary, ovoid and filamentous.

Mycobacteria are slender rods of varying lengths that sometimes show branching filamentous form resembling ‘fungal mycelium’. Hence, the name mycobacteria, meaning fungus like bacteria.
Although cytochemically gram positiive, the Mycobacteria do not take up the dyes of the gram stain because the cell walls are rich in lipids – Mycolic acid. Once a dye has been taken up by the cells they are not easily decolourised, even by acid-alcohol. Mycobacteria are therefore called as acid-fast bacilli. The genus includes animal and human pathogens as well as saprophytic members often referred to as atypical, anonymous, opportunistic, tuberculoid and MOTT (Mycobacteria other than typical tubercle) bacilli. Clasification of Mycobacteria (Tubercle Bacilli)
I. Slowly growing Mycobacteria
• Mycobacterium tuberculosis causes human tuberculosis in human and dogs.
• Mycobacterium bovis causes bovine tuberculosis in many animal species and also cause tuberculosis in human
• Mycobacterium africanum causes human tuberculosis.
• The human type (Mycobacterium tuberculosis) is primarily a pathogen for man. But can cause disease in cattle, pigs, dogs, monkeys, parrots and other species. The bovine type (Mycobacterium bovis) is a common cause of disease in domestic animal particularly cattle, pigs, cat, dogs and horse. The avian type (Mycobacterium avium) is primarily a pathogen for birds. But can cause disease in cattle, sheep, goat and pigs.