sheet (17)

made by: Mohammad jomaa

corrected by: abd. salman

date: 16-11-2016 *slides are within a bold style

Gram Positive Rod

Medically Important Gram-Positive Bacilli

Three general groups:

1) Endospore-formers

Bacillus contain 3 groups (bacillus anthracis /bacillus cereus /bacillus

thuringiensis), Clostridium contain 4 groups (Clostridium tetani /

Clostridium botulinum /Clostridium perfringens /Clostridium difficile)

2) Non-endospore-formers

Listeria, Erysipelothrix

3) Irregular shaped and staining properties (irregular rod shape)

Corynebacterium type corynebacterium diphtheria which cause

diphtheria , Proprionibacterium, Mycobacterium, Actinomyces, Nocardia

Corynebacterium, Proprionibacterium is non-acid fast bacteria

Mycobacterium, Actinomyces, Nocardia is acid fast bacteria

5:30 slide 4

SSppoorree--ffoorrmmiinngg BBaacciillllii

Genus Bacillus,Genus Clostridium

**it’s very dangers to humans

**it’s used as biological weapon

Consist of 3 groups :

Mycobacterium tuberculosis

Mycobacterium leprae

Mycobacterium avium-intracellulare

General Characteristics of the Genus Bacillus

• Gram-positive, endospore-forming, rods • Mostly saprobic also called saprophytic رمية التغذية

Saprobic mean depends on organic matter as nutrition (e.g cellular debris and death cell)

• Aerobic and catalase positive • Primary habitat is soil • 2 species of medical importance:

– Bacillus anthracis cause anthrax انجًرة انخبٍثت – Bacillus cereus cause food poising

Bacillus species are aerobes, the Clostridium species are anaerobes. Anthrax, is caused by bacillus anthracis so that culture in anaerobic jar . Because of its potent toxins, B anthracis is a major potential agent of bioterrorism and biologic warfare.

Bacillus cereus and Bacillus thuringiensis cause food poisoning and occasionally eye or other localized infections. Clostridium tetani, tetanus Clostridium botulinum, botulism the most dangerous food poisinig ** it produces toxin which cause paralysis

**1 mg of toxin is sufficient to kill human or laboratory animals

**Source from canned food because of bad storage condition Clostridium perfringens, gas gangrene

**most occur in diabetic patients (begin from finger of foot and elevate “ascending” the gas and enzyme is responsible for this ……in gangrene there is stop in blood flow to that tissue)

**the way to treat gas gangrene is the cut of the gangrenous origin or tissue

***but the problem is the bacteria responsible for gas gangrene (Clostridium perfringens) is spore forming bacteria which can distribute to site far than the surgical cut so that the spore reach the blood circulation and toxemia(toxin in blood)

**spore appears in x-ray as foggy area Clostridium difficile, pseudomembranous colitis.(normal flora in GI)

endospore

Slide 7 16:10

appearance. ”cut glass“are round and have a B anthracis Colonies of

**this figure show cells not colony

**cells appear as car box

**cells has particular (specific) border

**the site of spore is very important in diagnosis

BBaacciilllluuss aanntthhrraacciiss

• Large, block-shaped rods • Central spores that develop under bad conditions except in the living body (where

spore germinate) • Virulence factors (varies virulence factor) – polypeptide capsule and exotoxins • 3 types of anthrax:

– Cutaneous – spores enter through skin – Pulmonary –inhalation of spores by the respiratory tract – Gastrointestinal – ingested spores mostly for children who eat

contaminated food with spore to this type of bacteria

Slide 9

• In inhalation anthrax (Woolsorters’ disease) ( فرازي انصوفداء ), the spores from the dust of wool, hair, or hides are inhaled; phagocytosed in the lungs; and transported to lymph node where germination occurs (produce vegetative cell “bacillus anthraicis)

sporeيصاب به الذين يعملون في الصوف وتنظيفه فهم يستنشقون هذه ال

• This is followed by toxin production (such as… 1-exotoxin 2-enzyme 3-varitualy of virulence factor …in addition to the endospore itself) and the development of hemorrhagic and sepsis, which are rapidly fatal.

Slide 10

B. anthracis produce (virulence factor)

1. Capsule that resist phagocytosis which lead to distribution in human body

2. Anthrax toxins that are made up of three proteins

- protective antigen (PA)

- edema factor (EF)

- lethal factor (LF).

PPAA binds to specific cell receptors, and it forms a channel that mediates entry of

EF and LF into the cell.

EEFF is an adenylate cyclase ( edema toxin). EF activate adenylate cyclase which

convert ATP to produce cAMP which cause accumulation of fluid in the body

LLFF plus PA is the major virulence factors that cause of death in infected animals

and humans.

Slide 11 22:25

BBaacciilllluuss cceerreeuuss

• Common airborne and dustborne; usual methods of disinfection and antisepsis are ineffective continue its life cycle by proliferating and cause disease

• Grows in foods, spores survive cooking and reheating it have a high resistant power because it contain 1) Dipicolinic acid 2) calcium ion which give the bacteria its resistant and stability

• Ingestion of toxin-containing food causes nausea, vomiting, abdominal cramps and diarrhea; 24 hour duration

Slide 12

Food poisoning caused by B. cereus has two distinct forms 1. Emetic type, which is associated with fried rice cause vomiting 2. Diarrheal type, which is associated with meat dishes and sauces. cause diarrhea

These two forms have different sign and symptoms and different in incubation period B. cereus produces toxins that cause disease that is more an Intoxication than a Foodborne infection.

Cause edema

*milder disease

*like food poisining

*GIT infection

Caused by M.O itself Caused by exotoxin

produced by M.O

TThhee GGeennuuss CClloossttrriiddiiuumm

• Gram-positive, spore-forming rods

• Anaerobic and catalase negative

• 120 species

• Oval or spherical spores produced only under anaerobic conditions

• Synthesize organic acids, alcohols, and exotoxins and co2 +methane as metabolic end products

• Cause wound infections, tissue infections, and food intoxications

*the tetanus is found as result of contamination during birth and cause wound infection at the site where the umbilical cord is cut oxicitytand

Slide 15

CClloossttrriiddiiuumm ppeerrffrriinnggeennss

**ccaauusseedd bbyy vviirruulleennccee ffaaccttoorr wwhhiicchh ccaauussee ddiissssoollvvee aanndd ddeessttrruuccttiioonn ooff tthhee ssttrruuccttuurree ooff tthhee ttiissssuuee ((ccoollllaaggeenn bbyy ccoollllaaggeennaassee aanndd ootthheerrss))

**ffoouunndd iinn ssooiill ssoo tthhaatt ssoommee ddiiaabbeetteess ppaattiieennttss wwhhoo wwoorrkk iinn ggaarrddeenn aanndd hhaavvee ssmmaallll wwoouunndd wwhhiicchh aallllooww tthhee eenntteerriinngg ooff tthhee bbaacctteerriiaa ttoo tthhee hhoosstt cceellll aanndd ccaauussee ggaass ggaannggrreennee aallssoo tthheerree iiss nnoo bblloooodd ffllooww ttiissssuuee bbeeccoommee bblluuee iinn ccoolloorr

HHeeaalliinngg iinn ddiiaabbeetteess ppaattiieennttss iiss ddiiffffiiccuulltt..

(1) gas gangrene. - All types of C perfringens produce the alpha toxin.

• Clostridium perfringens Most frequent clostridia involved in soft tissue and wound infections - myonecrosis

• Spores found in soil (sub terminal) • Predisposing factors – surgical incisions,

compound fractures, diabetic ulcers, septic abortions, puncture wounds, gunshot wounds

• Virulence factors

– toxins : alpha toxin – causes RBC rupture, a necrotizing that cause edema and tissue destruction

– collagenase digest collagen

– hyaluronidaselysis hyalurondic acid

– DNase lysis DNA Subtermenal spore

- Gas gangrene occurs when a soft tissue wound is contaminated by C perfringens.

- Once infection is initiated, the organisms elaborate necrotizing toxins; CO2 and

H2 accumulate in tissue, edema occurs

- Therapy involves surgical removal of the infection and administration of penicillin G.

*this M.O ((CClloossttrriiddiiuumm ppeerrffrriinnggeennss)) enters the body only throughout wound and .t enter the body throughout respiratory tract’can but trauma

The gas have very bad smell.

See slide 15 to see the gas gangrene

Slide 16 33:00

(2) Food poisoning - Enterotoxin produced and released during sporulation. The incubation period for the abdominal pain, nausea, and acute diarrhea is 8–24 hours.

Slide 17

CClloossttrriiddiiuumm ddiiffffiicciillee

**iitt iiss tthhee oonnllyy nnoorrmmaall fflloorraa ooff cclloossttrriiddiiuumm (( ootthheerrss aarree ppaatthhooggeennss )) aanndd ccaauussee ddiisseeaassee iinn

ppeerrssoonn wwhhoo ccoonnttaaiinn tthhiiss bbaacctteerriiaa iinn aabbnnoorrmmaall ccoonnddiittiioonn.. • Caused Pseudomembranous colitis. • It is part of the normal gastrointestinal flora in 2–10% of humans. • The organisms are relatively resistant to most commonly used antibiotics.

*in the intestine there is more than one type of bacteria

*there is no antibiotics for all type of M.O

*antibiotics is specific for special type of M.O (e.g… antibiotics for facultative anaerobic

bacteria)

*normal flora may cause infection by :

1) translocation from its original location

2)increased in number

There is screening tests for normal flora .

• Associated with or following antibiotic use, the normal gastrointestinal flora is

suppressed and C difficile proliferates, producing cytopathic toxin and enterotoxin. • Symptoms of the disease vary from diarrhea alone to necrosis of mucosa with

accumulation of inflammatory cells and fibrin, which forms the pseudomembrane. *women doctor have to increase the straining for the normal flora (streptococcus) because it is very important in protective of the baby

Slide 19

• CClloossttrriiddiiuumm tteettaannii • Common resident of soil and GI tracts of animals • Causes tetanus or lockjaw تشنج في الفك ) الفك المقفول ( , a neuromuscular disease

spasm تشنجات

*produce very strong exotoxin (neurotoxin because it works on neurons) it named this

because it is located in neurons

• Most commonly among geriatric patients and IV drug abusers; neonates in developing countries It is club shaped

Pseudomembranous colitis ( lead later

to necrosis then gas gangrene.)

le

Normal intestine

Terminal spore

Slide 20

which causes tetanus, are present throughout the ,Clostridium tetaniSpores of -

environment.

- They germinate in tissue and elaborate the toxin tetanospasmin, a potent neurotoxin

Make continuous contraction

*toxin include 1-tetanospasmin (the strong one) 2-tetanolysin lysis RBC - The toxin spreads along nerves to the central nervous system, where it binds to

gangliosides, suppresses the release of inhibitory neurotransmitters (GLYCINE AND GAMMA-AMINO BUTYRIC

ACID) Across the synaptic cleft, and yields prolonged muscle spasms. - Upper airway obstruction or involvement of the diaphragm, and organ dysfunction has emerged as the major cause of death. - More than 50% of tetanus cases follow minor injuries. - Tetanus is totally preventable: active immunity is induced with tetanus toxoid (part of M.O that’s used in vaccine ) (formalinized tetanus toxin). Tetanus toxoid is part of

routine childhood DDTTaaPP (diphtheria, tetanus, acellular pertussis) immunizations.

** it is may be fetal because it may produce continues contraction of the diaphragm which affect the respiratory process

فً فخ غرٌب وقعنا فً عانى االيراض ضعنا

كٍف انخروج كٍف انخروج ين اٌن انطرٌق

عانى غرٌب انًعانى نواجه انبكتٍرٌا نقاوو

نهقى عذوا ونقابم انف صذٌق

.....

انا نن ٌنقضنا االيم ين عانى انذٌجٍتال )قصذ انشاعر به تخصص انطب( نعهى

بم انغش يعا