Systematic bacteriology is a branch of microbiology that focuses on the classification, identification, and nomenclature of bacteria. It involves the systematic organization of bacteria into taxonomic groups based on their morphological, physiological, biochemical, and genetic characteristics. The goal is to create a comprehensive and structured framework for understanding the diversity of bacterial species.

1. UNIT-3 AND 4

2. LEPTOSPIRA
•Leptospirosis is a zoonosis with protean clinical manifestations caused by pathogenic
spirochetes of the genus Leptospira. Synonyms for the disease include Weil's disease,
Weil-Vasiliev disease, Swineherd's disease, rice-field fever, waterborne fever,
nanukayami fever, cane-cutter fever, swamp fever, mud fever, Fort Bragg fever,
Stuttgart disease, Mgunda fever, and Canicola fever.
•The epidemiology, microbiology, clinical manifestations, and diagnosis of
leptospirosis will be presented here. The treatment and prevention of this disease are
discussed separately

4. MORPHOLOGY &COLONY CHARACTERS
•Leptospira interrogans causes leptospirosis, a usually mild illness that may result in
liver or kidney failure.
Leptospira is a flexible, spiral-shaped, Gram-negative spirochete with internal
flagella. Leptospira interrogans based on cell surface antigens.
•Leptospira organisms are very thin, tightly coiled, obligate aerobic spirochetes
characterized by a unique flexuous type of motility. The genus is divided into two
species: the pathogenic leptospires L interrogans and the free-living leptospire L
biflexa.
•The diagnosis of leptospirosis should be considered in any patient with an acute
illness characterized by headache, myalgia, fever, chills and conjunctival suffusion,
and in any patient in whom “aseptic meningitis” develops following an acute febrile
illness of five to seven days' duration.

6. BIOCHEMICAL CHARACTERS AND CULTIVATION
•Leptospirosis can be diagnosed on the basis of the presence of IgM
antibodies by ELISA, in a single serum sample collected during the acute
phase of the illness. A sample taken after two weeks is required to confirm
the results.
•It Grows Best under Aerobic Conditions, at 28-30 degree celsius best
demonstrate in Semisolid Agar Medium such as EMJH and Stuart and
Fetcher”s Medium.

10. ZOONOSIS
•Zoonotic diseases are of major concern worldwide. The word 'Zoonosis'
(Pleural: Zoonoses) was introduced by Rudolf Virchow in 1880 to include
collectively the diseases shared in nature by man and animals.
Later WHO in 1959 defined that Zoonoses are "those diseases and
infections which are naturally transmitted between vertebrate animals
and man".
• The infectious diseases such as bacterial, viral, fungal, protozoal and
parasitic are responsible for most losses in the food animals, therefore of
great economic importance.

12. PRESERVATION OF BACTERIA
•Bacteria can survive for a short period of time at 4°C. For strains that are used daily or weekly,
cultures grown on agar slants or plates can be stored in a refrigerator assuming that precaution has
been taken to avoid contamination.
• Cultures should be prepared using standard techniques and then sealed before storing. For slants,
we recommend using screw capped tubes.
• For cultures on Petri dishes, the plates need to be sealed with Parafilm.
Sealing the plates not only helps to prevent molds from sneaking into the plates, but it slows the agar
from drying.
•Freezing is a good way to store bacteria. Generally, the colder the storage temperature, the longer
the culture will retain viable cells.
•For long term storage, microorganisms are cryopreserved at temperatures below freezing (-20°C, -
80°C, or liquid nitrogen) .Cryopreservation is suitable for a wide range of bacteria, algae, fungi,
viruses, and protozoa.
•Cryopreservation and lyophilisation both are well-known methods for long-term preservation of
microbial cultures. Use of ultra-low temperature for preservation of microorganism is a traditional
practice in every microbiological laboratory.

15. MECHANISM OF DRUG ACTION
•By Enzymes
•By Receptors
•By Ion Channels
•By Transport Process
•By Physical /Chemical Properties
The actions of the majority of drugs are intimately related to their three-dimensional chemical
structure. Seemingly minor alterations to a drug molecule can result in major changes in
pharmacological properties.
This can be exploited to develop drugs with a more favorable therapeutic index, fewer side effects
or a shorter or longer duration of action.
The penicillins and cefalosporins has led to the availability of many new groups or generations of
antibacterial.
The actions of drugs on receptors that lead to responses are governed by the same factors that
influence the rate and direction of chemical or biochemical reactions, i.e.:
•temperature
•the concentration of each reactant (including cofactors)
•catalysts (enzymes that activate drug precursors).

16. DRUG RESISTANT GENES
•Microbes, such as bacteria, viruses, fungi, and parasites, are living organisms that
evolve over time.
•The primary function is to reproduce, thrive, and spread quickly and efficiently.
•Microbes adapt to their environments and change in ways that ensure their survival.
• If something stops their ability to grow, such as an antimicrobial, genetic changes can
occur that enable the microbe to survive. There are several ways this happens