Identification and taxonomy of bacteria

Question 1

Explain the different between gram positive and gram negative cell walls for bacteria

Answer 1

gram positive cell wall; has a thick layer of peptidoglycan however for gram -ve its small
game +ve can survive UR rays and drying out however gram -ve can’t

Question 2

What is an endospore

Answer 2

Endospore
produce by gram +ve
very resistant to drying out and uv light
spores are not permeable
in the body they are dominant until the right conditions come along

Question 3

List the groups of bacteria

Answer 3

groups of bacteria 
-Mollicutes
-Cyanobacteria 
-Fusobacteria 
-Proteobacteria: gram -ve
PVC group
FBC group
spirochetes
Acinetobacteria 
-Firmicultes; mostly gram +ve

Question 4

List the classification of bacteria

Answer 4

classification of bacteria
genus; collection of different species sharing major properties
species; small group of organism which are hard to distinguishing
biovar; strains of species with different biochemical and phenotypical characteristics
serovar; stain of species which differs in serology
phagetype; bacteria specific phages used (defines clones)
genotype: defines clade, determined using DNA fingerprinting methods

Question 5

List the ways of identifying bacterial

Answer 5

List the ways of identifying bacterial
direct methods; need to increase and purity the bacteria
eg. culture
Molecular methods (PCR amplification, cloning)
or indirectly; immune response in the host

Question 6

Explain culturing for identification for bacteria

Answer 6

culturing for identification
purpose; ID bacteria based upon appearance
permits selections and transfer of different species from a mixed culture
a single bacterial cells is put on the surface of a nutritive medium and it begins to divide

Question 7

For cultures for identification of bacteria list the different types of media and incubation

Answer 7

different types of media and incubation 
incubation;
aerobic 
anaerobic 
microaerobic 
CO2 enhanced 
media;
enrichment 
selection differential
decide on temperature which is depend on host match the hosts temperature

Question 8

List the types of Haemolytic patterns on Blood agar

Answer 8

Types of haemolytic patterns
Gamma no haemolysis
Alpha
Beta; zones of clearing where there is totally haemolysis

Question 9

List the types of preliminary identification

Answer 9

types of preliminary identification 
catalase- 
oxidase-
spot indole 
motility 
urease
gram stain 
KOH gel formation

Question 10

List the testes which are used for secondary identification

Answer 10

secondary identification

• biochemical tests
• serological tests

Question 11

Define the Antimicrobial susceptibility test

Answer 11

Antimicrobial susceptibility test;

detection of resistance to antibiotics used to treat bacteria