Many people prefer reading " medical microbiology and immunology" by levinson.
In Basic Bacteriology chapter 2, 5, 9 and 13 are important for exam and viva. Chapters 10 to 12 are important pharmacologically but these things could be cover in pharma as well. In chapter 7, endotoxicnstables 7-9 to 7-12 and endotoxins.
In Clinical Bacteriology i would like to add imp bacterias. Starting with gram positive cocci

Staphylococcus
All staphylococci are catalase +ve. Imp Staphylococci are Staph. aureus and Staph. epidermids.

Staph. aureus

1. Major cause of skin infections (form abscess, boils)
2. cause surgical wound infections, septicemia and hospital aquired pneumonia
3. kawasaki syndrome
4. Food poisoning ( production of enterotoxin)

Lab investigations

1. form golden yellow colonies
2. coagulase +ve
3. Ferment manitol and beta hemolytic ( causes lysis of RBCs)

Staph. epidermidis

1. cause endocarditis and prosthetic joint infection.
2. cause hospital acquired infections

Lab

1. coagulase -ve
2. form white colonies and are non hemolytic

Streptococci

All streptococci are Catalase -ve. Beta hemolytic streptococci have two imp antigens which are C carbohydrate and M protein. Important streptococci include S. pyogenes and S. pneumoniae.

Streptococcus. pyogenes

1. common cause of Throat infections ( pharyngitis , cellulitis)
2. cause toxic shock ( through production of exotoxin)
3. cause immune mediated post stretococcal pathogenesis which could lead to Rheumatic Fever or Acute glomerulonephritis.

Labs:

1. Beta hemolytic. (group A beta hemolytic)
2. Bacitracin sensitive
3. Throat swab contaning bacterial antigens (Agglutination of colored latex particles occures)

S. Pneumoniae

1. most common cause of community aquired pneumonia ( Typical pneumonia )
2. Also cause otitis media, sinusitis and meningitis

Labs:

1. Sputum is red or brown rusty color
2. Colonies are alpha hemolytic and are bile soluble.
3. quellung reaction test
4. lancet shaped, gram positive diplococci

Gram negative cocci
Gram negative cocci include Neisseria meningitidis and Neisseria gonorrhoeae. They are oxidase +ve. Cant form colonies on blood agar so Chocolate agar is used.

Neisseria meningitidis

1. common cause of meningitis and meningococcemia.
2. most commonly affected persons are b/w 2 to 18 years of age
3. three main virulence factors are i. Polysaccharide capsule ii. Endotoxin iii. IgA

Lab:

1. Oxidase +ve gram -ve diplococci
2. fermentation of maltose

Neisseria gonorrhoeae

1. gonorrhea (STD)
2. PID (cervicitis and salpingitis)
3. In neonates can cause ( conjunctivitis)

Lab:

1. oxidase +ve gram -ve diplococci
2. do not ferment maltose.

I would like to add respective module name , with each organism, for those students which follow module system.

Gram Positve Rods

This include four genera, which are i. Bacillus ii. Clostridium, iii. Cornyebacterium etc
Bacillus:

Bacillus anthracis ( Respitratory module)

1. cause Pulmonary anthrax when its spores are inhaled ( woolsorter's disease)
2. cause cutaneous anthrax when spore enter through wound from soil
3. its capsule is composed of D-glutamate , making it antiphagocytic.

Labs:

1. In case of pulmonary anthrax, mediastinal widening seen on chest xray
2. hemorrhagic mediastinitis could be present
3. Gram +ve rods in chains seen on gram staining
4. direct antibody fluorescent antibody test or ELISA test

Bacillus cereus (GIT module)

1. food poisoning after eating reheated fried rice.
2. watery, nonbloody diarrhea

Mechanism of enterotoxin
it add adenosin diphosphate ribose to G protein which sitmulates adenylate cyclase and leads to increase conc. of cAMP inside enterocyte. This mechanism is same as that of Cholera toxin.
Labs:
Not specific
Clostridium
bacterias in this group are anaerobic, spore forming, gram +ve rods

Clostridium tetani ( neuro module)

1. cause tetanus i.e lockjaw
2. mode of transmission is by spore present in soil through skin wounds.
3. exotoxin is produce by bacteria at wound site, which than carried to CNS, by mean retrograde transport.
4. In CNS it act on ganglioside receptors and blocks realease of inhibitory transmitters at spinal synapses.

Labs:

1. No specific diagnostic but there may be clinical findings which are
2. lockjaw
3. exaggerated reflexes
4. Arching of back muscles ( opisthotonos),
5. Can be differentiate from botulinum toxin because in tetanis there is spastic paralysis of muscles while in case of botulism it is flaccid paralysis.

Clostridium botulinum ( neuro module)

1. Causes botulism by means of exotoxinin food.
2. Mostly by canned food.
3. botulinum toxin blocks release of acetylcholine.
4. preparation from exotoxin A used as Botox.

Clostridium perfringens ( GIT module)

1. causes food posioning by producing exotoxin. exotoxin causes diarrhea acting as a superantigen, just like S. aureus.
2. also cause gas gangrene.
3. Watery diarrhea with cramps

Clostrudium difficile (GIT module)

1. form pseudomembranes on colonic mucosa.
2. mostly commonly effect patients on prolong antibiotics therapy.
3. Causes non bloody diarrhea.

Labs:

1. Stool samples for presence of exotoxin and sigmoidoscopy reveal pseudomembranes on mucosa.

C. diphtheriae ( Respiratory module )

1. causes Diphtheria.
2. its toxin inhibits protein synthesis by ADP-ribosylation of elongation factor 2.

Labs:

1. Thick, gray pseudomembrane over the tonsils and throat.
2. L or V shaped gram +ve rods on Loffler's medium.
3. Staining by gram stain and methylene blue.

Gram Negative Rods (GIT)
Most common features of all the gram -ve rods of the enteric tract ( except P. aeruginosa )are i. Fcaultative anaerobes ii. ferment glucose iii. oxidase negative iv. reduce nitrates to nitrites.

E. coli ( GIT Module and KUB Module )

1. Most common cause of UTI (urinary tract infection).
2. major cause of traveler's diarrhea.
3. also cause neonatal meningitis
4. O157:H7 strain causes bloody diarrhea and hemolytic uremic syndrome.
5. Pathogenisis is mostly through enterotoxins

Labs:

1. Ferment lactose and form Pink colonies.
2. On EMB agar, form green sheen colonies.
3. E.coli O157:H7 doesnt ferment sorbitol.

Salmonella

1. common cause of typhoid fever (S.typhi).
2. causes enterocolitis.
3. animal source of salmonella is poultry and eggs.
4. S. typhi is transmitted only by humans. ( carrier rate is higher among women)

Labs: ( are important for exam and viva )

1. In typhoid fever rose spots may present on abdomens.
2. Widal test commonly used for detecting antibodies in patient serum.
3. Do not ferment lactose but produce H2S.