Introduction to Bacteriology

Bacteriology

Morphological classification:

Division	Sub Division	Examples	Causative diseases
Cocci	Monococcus(they remain single)
	Diplococcus (they remain double)
	Streptococcus(they remain in chain)	1.       S.pyogenes     2.       S.pneumoniae     3.       S.bovis     4.       S. agalactiae     5.       S. suis     6.       S. mutans     7.       S. sanguinis     8.       S. mitis	·         pharyngitis, cellulitis(host human)     ·         Pneumonia     ·         Biliary or urinary tract infection     ·         Neonatal meningitis, sepsis     ·         Meningitis (host swine)     ·         dental caries(host: human)     ·         endocarditis, dental caries(host: human)     ·         endocarditis(host:human)
	Staphylococcus(They remain in cluster)	S.aureus	1. Skin infections: impetigo, furuncles, carbuncles, paronychia, cellulitis, folliculitis and hydradenitis suppurativa, surgical woung infections, eyelid infections (blepharitis), breast infection (mastitis) 2. Septicemia(sepsis): sepsis can originate from any localized lesion, specially wound infection, or as a result of intravenous drug abuse 3. Heart: Infective endocarditis on normal or prosthetic heart valves 4. Bones and joints: Osteomyelitis (in children), septic arthritis 5. Lung: Pneumonia in post-operative patients or following viral respiratory infection 6.CNS: Meningitis, brain abscess 7. Food poisoning (gasteroenteritis) caused by enterotoxin 8.Toxic shock syndrome (caused by toxic shock syndrome toxin) 9. Scaled skin syndrome (caused by exfoliatin)
		S.epidermidis	1. Infections are associated with intravascular devices (prosthetic heart valves, shunts, etc.) 2. also commonly occur inprosthetic joints, catheters, and large wounds 3. Catheter infections along with catheter-induced UTIslead to serious inflammation and pus secretion.
		S.aprophyticus	1. Staphylococcus saprophyticus is a leading cause of cystitis in young women. 2. S. saprophyticus shares many clinical features of urinary tract infection caused by Escherichia coli, but differs in pathogenesis, seasonal variation, and geographic distribution.
Bailli	Gram possitive	Crynebacterium species(they are also aerobic):     1.       Corynebacterium diphtheriae     2.       C.ulcerans     3.       C. haemolyticum     4.       C.psudotuberculosis     5.       C.renale     6.       C.psudodiphtheriticum     7.       C.xerosis     8.       C.acnes     9.       C.psudo-genitalium     10.   C.hofmanii	1.       Diptheria     2.       C. ulcerans has been known to cause diphtheria and diphtheria-like infections in patients     3.       (Red water disease) Bacillary hemoglobinuria is an acute, infectious, toxemicdisease caused by Clostridium haemolyticum     4.       Ulcerative lymphangitis in cattle and horses causes an infection in the lower limbs with abscesses in the pectoral lymph nodes, and contagious open sores     5.       It is a pathogenic bacterium that causes cystitis and pyelonephritis in cattle     6.       ???     7.       Sepsis     8.        Acne vulgaris
		Clostridium species(they are non-acid fast, rod shaped with rounded ends, they are sporeforming and obligate anaerobic they also produce exotoxins):     1.       Oval shaped: Cl.perfringens, Cl.septicum, Cl.botulinum     2.       Oval terminal: Cl.tetani     3.       Spherical terminal: Cl.tetanomorphum	1.        perfringens grow in the intestines, and secrete exotoxin that causes food poisoning Perfringens poisoning can also lead to anotherdisease known as enteritis necroticans (also known as pigbel) and Cl.botulinum causes wound botulism and infant botulism with is caused by canned or tinned or bottled food, alkaline vegetable like green beans, peppers and mushrooms, smoked fish etc     2.       Tetanus, that causes muscle stiffness and lockjaw
		Basillus species:     a.       Pathogenic (in human): 1.Bacillus anthracis 2. Bacillus cereus     b.      Non-pathogenic: 1. Basillus subtilis 2. Bacillus mycoides 3. Bacillus anthacoides	Basillus anthracis causes “anthrax”
	Gram negative	1.       E.coli     2.       Proteus     3.       Pseudomonas     4.       Salmonella species     5.       Shigella specis     6.       Helicobacter     7.       Campylobacter
Spirochaetes	A.      Pathogenic: 1. Treponema 2.Borrelia 3. Saprospira     B.      Non-pathogenic: 1.Spirocheta 2.Cristispira 3. Saprospira	Treponema: T. pallidum                         T.pertenue Borrelia: B.recurrentis                  B.burgdorferi Leptospira: L.interrogans	Syphilis Yaws Repalsing fever Lyme disease Leptospirosis
Vibrio (comma shaped)	A.Halophilic (marine-Capable of groing in media with added salt-NaCl) B. Non halophilic (Cannot grow in media with added salt NaCl) a) Vibrio cholerae O-1 (causes epidemic disease) 1. Classical	A. Vibrio parahemolyticus, V.vulnificus,V.mimicus B.Vibrio cholerae

On basis of gram staining:

Classification	Other type	Species	Example	Possible disease
Gram possitive	Cocci	Streptococci	1.       S.pyogenes     2.       S.pneumoniae     3.       S.bovis     4.       S. agalactiae     5.       S. suis     6.       S. mutans     7.       S.sanguinis     8.       S. mitis	·         pharyngitis, cellulitis(host human)     ·         Pneumonia     ·         Biliary or urinary tract infection     ·         Neonatal meningitis, sepsis     ·         Meningitis (host swine)     ·         dental caries(host: human)     ·         endocarditis, dental caries(host: human)     ·         endocarditis(host:human)
		Staphylococci	S.aureus	1. Skin infections: impetigo, furuncles, carbuncles, paronychia, cellulitis, folliculitis and hydradenitis suppurativa, surgical woung infections, eyelid infections (blepharitis), breast infection (mastitis) 2. Septicemia(sepsis): sepsis can originate from any localized lesion, specially wound infection, or as a result of intravenous drug abuse 3. Heart: Infective endocarditis on normal or prosthetic heart valves 4. Bones and joints: Osteomyelitis (in children), septic arthritis 5. Lung: Pneumonia in post-operative patients or following viral respiratory infection 6.CNS: Meningitis, brain abscess 7. Food poisoning (gasteroenteritis) caused by enterotoxin 8.Toxic shock syndrome (caused by toxic shock syndrome toxin) 9. Scaled skin syndrome (caused by exfoliatin)
			S.epidermidis	1. Infections are associated with intravascular devices (prosthetic heart valves, shunts, etc.) 2. also commonly occur inprosthetic joints, catheters, and large wounds 3. Catheter infections along with catheter-induced UTIslead to serious inflammation and pus secretion.
			S.aprophyticus	1. Staphylococcus saprophyticus is a leading cause of cystitis in young women. 2. S. saprophyticus shares many clinical features of urinary tract infection caused by Escherichia coli, but differs in pathogenesis, seasonal variation, and geographic distribution.
	Basilli	Croynebacterium species
		Clostridium species
		Bacillus species
Gram negative	Cocci	Neisseria species	Neisseria gonorrhoea	Gonorrhoea
	Bacilli	E.coli Proteus Pseudomonas Salmonella Shigella specis Helicobacter Campylobacter	Escherichia coli Proteus: Proteus vulgaris,  P. mirabilis,  P. penneri Psudomonas:p. fluorescens, P. putida, P. syringae, P.stutzeri, P. ryzihabitans, P. luteola etc Salmonella: Salmonella enterica & Salmonella bongori Shigella: Shigella species are classified by four serogroups:      ·         Serogroup A: S. dysenteriae (15 serotypes)      ·         Serogroup B: S. flexneri (six serotypes)      ·         Serogroup C: S. boydii (19 serotypes)      ·         Serogroup D: S. sonnei (one serotype)	E.coli: causes diarrhea, urinary tract infection P.vulgaris: It is known to cause wound infections P. mirabilis: This rod-shaped bacterium has the ability to produce high levels of urease, which hydrolyzes urea to ammonia (NH3), so makes the urine more alkaline. If left untreated, the increased alkalinity can lead to the formation of crystals of struvite, calcium carbonate, and/or apatite, which can result in kidney stones.  Psedomonas: severe infections occur in people who are already hospitalized with another illness or condition, or people who have a weak immune system. Pseudomonades are fairly common pathogens involved in infections acquired in a hospital setting. A pathogen is a microorganism that causes disease. Infections acquired in a hospital are called nosocomial infections. Infections can occur in any part of the body. Shigella: Shigellosis is a diarrheal disease caused by a group of bacteria called Shigella. Shigella causes about 500,000 cases of diarrhea in the United States annually 1. There are four different species of Shigella: Shigella sonnei (the most common species in the United States)

On the basis of Acid fast staining:
1. Acid fast: Mycobacterium tuberculosis

2.Non-acid fast: Streptococcus pyogenes, E.coli & most of the bacteria

On the basis of Oxygen requirement:

1.       Obligate aerobe: They require 02  and cannot survive without O2
example: Mycobacterium tuberculosis(pulmonary tuberculosis is common because of rich oxigen)

2.       Facultatitve anaerobe: Grows with or without O2 Example: Staphylococci, E.coli

3.       Obligate anaerobi: Grows only in absence of O2, they cannot live in the presence of O2. Example: Clostridium species

4.       Aerotolerant anaerobic: Grows in presence of O2 but doesn’t use it.

5.       Micro aerophilic: Grows in low oxygen concentration

On the basis of temperature:

1.       Psychrophilic: Grows best at low temperature (15-20 C)

2.       Mesophilic : Grow best at body temperature (30-37 C)

3.       Thermophilic: Grow best at high temperature (50-60 C)

On the basis of spore forming bacteria:

1.       Spore forming bacteria: Clostridium species, Bacillus species, Sporosercina

2.       Non spore forming bacteria: Streptococcus pyogenes, Staphylococcus aureus and most of the bacteria