Haemophilus & other enteric bacilli
Haemophilus
Chapter 14
Microbiology for Surgical Technologists
Haemophilus
Nonmotile
Gram-negative rods
Facultative anaerobe, but prefer an aerobic environment
Grow in pairs or short chains
Found in the mucous membranes of the respiratory and genital tracts of humans
Haemophilus
(continued)
Means blood-loving
Require one or two factors that are present in blood
Specifically heme (the old name is the “X” factor)
Contracted through droplet inhalation or sexual contact
Haemophilus influenzae
6 serotypes – a through f
Type b is most virulent
Virulence factors
Antiphagocytic
Peptidoglycan – in cell wall, damages the blood-brain barrier
Exotoxin – inhibits the movement of respiratory cilia
Fimbriae – aids cell adherence to tissue
Adhesins - aids cell adherence to tissue
Haemophilus influenzae
(continued)
Type b can spread from the respiratory tract to the sinuses and middle ear
It is the most common cause of septic arthritis and cellulitis in children 2 and under
Can lead to pneumonia and meningitis
Can be deadly in small children and elderly
Haemophilus influenzae
(continued)
Neurological conditions that can occur following recovery from H. influenzae meningitis are:
Hearing loss, blindness, chronic convulsions, hydrocephaly, and developmental disabilities
Since the introduction of the conjugated vaccine, the US has seen an almost 100% reduction in the incidence of H. influenzae type b
Haemophilus influenzae
(continued)
Treatment
Antibiotic therapy
Clinical trials are being done in infant to include dexamethasone (a steroidal anti-inflammatory drug).
It has been very successful in reducing meningeal swelling and the incidence of hearing loss
Haemophilus influenzae
biotype aegyptius
Causes pinkeye
A highly contagious purulent conjunctivitis
Infection can range from mild to severe
Mild – involving only the blood vessels of the eye
Severe – with lacrimation, swelling and photophobia
It can cause an even more severe form called Brazilian purpuric fever
Haemophilus ducreyi
Endemic in some parts of the world
High rates associated with poor socioeconomic and sanitary conditions
In the US it is common among crack addicts, prostitutes, and alcoholics
Causes chancroid
Sexually transmitted disease that manefests as soft chancres (ulcerations)
Haemophilus ducreyi
(continued)
Immunity does not develop after exposure
Treatment of choice is a new drug called azithromycin
Gram-Negative
Enteric Bacilli
Chapter 15
Microbiology for Surgical Technologists
Escherichia coli
The #1 cause of nosocomial infection
Gram-negative rod that grows singly
Part of the normal flora of the GI tract in humans
Help to prevent growth of pathogenic bacteris and synthesizes vitamins
Most strains are harmless
Can be the cause of endogenous infections
An infection caused by an organism that is normal flora
Escherichia coli
(continued)
Causes urinary tract infections, sepsis, diarrheal disease, and neonatal meningitis
Immuno-compromised or debilitated pts are at higher risk for infection
Four types of pathogenic strains
Enteropathogenic
Enterotoxigenic
Enterohemorrhagic
enteroinvasive
Escherichia coli
(continued)
Diarrhea
Enteropathigenic E. coli (EPEC)
Often the cause of diarrheal disease breakouts in nurseries
The microvilli in the intestinal tract are destroyed
Usually resolves in 5 to 15 days
Infants can quickly become dehydrated requiring intravenous fluid replacement
Escherichia coli
(continued)
Enterotoxigenic E. coli (ETEC)
Referred to as “traveler’s diarrhea”
Exotoxins that are produced are responsible for the symptoms
Individuals that live in countries with ETEC often have protective antibodies
Antibiotic therapy may be needed along with IV fluid replacement
Escherichia coli
(continued)
Enterohemorrhagic E. coli (EHEC)
Causes hemorrhagic colitis
Severe form of bloody diarrhea
Referred to as E. coli 0157:H7
Found in the intestines of healthy cattle
During the slaughtering and processing the microbes contaminate the beef
EHEC is acquired from ingesting raw or undercooked beef, unpasteurized milk, and other raw contaminated foods
Escherichia coli
(continued)
Enterohemorrhagic E. coli (EHEC) (continued)
Meat contaminated with EHEC looks and smells normal
Only a small number of cells can cause infection
Other methods of becoming infected include:
Swimming in or drinking sewage-contaminated water
Person to person contact
Bacteria in stools can be passed if proper hygiene habits are not practiced
Escherichia coli
(continued)
The CDC estimates that 20,000 become ill from EHEC annually and 250 die
It is also responsible for causing hemolytic uremic syndrome (HUS)
Can be fatal
HUS involves thrombocytopenia, acute renal failure, and gemolytic anemia
Thrombocytopenia is the decrease in the number of blood platelets
Escherichia coli
(continued)
Pts with HUS most likely require hemodialysis and blook transfusions
Most HUS pts are children 5 and under
Once symptoms appear antibiotic therapy is useless, and the disease must run it’s course
Those who survive often have chronic genitourinary complications due to kidney and urinary tract damage
Escherichia coli
(continued)
EHEC Virulence factors
Produces verotoxins that destroy the inner layer of blood vessels
Shiga-like toxin which aids the ability of the bacterial cell to adhere to tissue
Both toxins are identical to the toxin produced by Shigella dysenteriae
Escherichia coli
(continued)
Enteroinvative E. coli (EIEC)
Causes a type of dysentery similar to shegellosis, but not as virulent
Children are most susceptible
Is also common among travellers
Escherichia coli
Escherichia coli
(continued)
Urinary Tract Infections
(UTI)
Common infections in infants that are still in diapers, pts with indwelling catheters, and females
Responsible for the majority of nosocomial UTIs
Can cause pyelonephritis
Severe kidney infections
Escherichia coli
(continued)
UTI
(continued)
Caused by nephropathogenic E. coli (NPEC)
Has a capsule and pilus that add to virulence
Symptoms include side pain radiating to the back, dysuria, frequent urination, and hematuria
Escherichia coli
(continued)
E. coli is a common cause of meningitis in infants
Mortality rate is high
From 40% to 80%
The majority of those that survive will display neurologic deficits and/or develop mental abnormalties
It is rarely implicated as the cause of adult meningitis
Escherichia coli
(continued)
Treatment
In all cases, accept EHEC, antibiotic therapy is successful
Pts usually do not seek treatment for diarrhea unless they become dehydrated, individuals with a sudden onset of bloody stools should seek medical treatment immediately.
Klebsiella
Klebsiella pneumoniae
Causes approx 3% of community or nosocomial bacterial pneumonias
Tends to affect those who already have a disease such as diabetes, alcoholism, or COPD
The elderly are prone to developing lobar pneumonia
A hemorrhagic necrotizing consolidation of the lungs
Klebsiella pneumoniae
(continued)
The bacteria are responsible for the necrotic destruction of the alveoli, abscess formation in the lung, and production of sputum that is thick and red
Referred to as “currant jelly” sputum because of it’s appearance
Cells have a gelatinous capsule that inhibits phagocytosis
If not treated quickly it is often fatal
Klebsiella pneumoniae
(continued)
Causes empyema
Pus surrounding the lung
Causes irritation and scar formation
Chest x-rays reveal lung abscesses in advanced cases
Can also cause nosocomial UTIs, wound infections, and burn infections
Highly resistant to antibiotic therapy
Empyema
Yersinia
Three species important to the medical community
Yersinia pestis
Yersinia pseudotuberculosis
Yersinia enterocolitica
Yersinia pestis
Bubonic Plague
Also known as the
Black death
Yersinia pestis
(continued)
Responsible for some of the greatest epidemics in history
It eliminated approx 1/3 of the population of the world between 1348 and 1530
No one knows why that epidemic stopped
No major outbreaks have occurred in over a century
Likely due to improved pest control and insecticides
Yersinia pestis
(continued)
Humans contracted the disease from the bite of an infected rat flea
Upon infection the cell loses its capsular layer and most are destroyed by phagocytosis
A few will enter tissue that provide protection and resynthesize the capsule and other virulent agents
Yersinia pestis
(continued)
The infection quickly spreads to the lymph nodes
They become tender swollen, tender and hot
They then become hemorrhagic
Giving rise to the black colored buboes
Hence the name bubonic plague
The infection invades the blood and spreads to the spleen, liver, and lungs
The result is pneumonia with a productive cough filled with the pathogen, infecting the environment
The Plague
Cutaneous infection
The Plague
Inguinal Buboes
Yersinia pestis
(continued)
Death can occur within 24 hours of the initial signs of infection
There are few drug resistant strains
Control measures have centered on the elimination of the rat flea
It is highly unlikely that it will ever be eradicated
Yersinia pseudotuberculosis
A pathogen of rodents and bird, but can infect humans
Is distinguished among other Yersinia species because it is motile
Produces large nodules in the Peyer’s patch and mesenteric lymph nodes
The Peyer’s patch is a group of lymph node located at the terminal ilial junction
May cause abscesses and require intestinal resection with anastomosis
Yersinia enterocolitica
A pathogen of cattle, pigs, deer, and birds
Excreted in the feces and can contaminate dairy products and drinking water
Humans can become infected by eating raw or undercooked pork products
The disease is called yersiniosis
Causes severe diarrhea with necrosis of the Peyer’s patch, liver and splenic abscesses, and chronic lymphadenopathy (swelling of the lymph nodes
Yersinia enterocolitica
(continued)
Often confused with appendicitis because of the right lower quadrant pain
An incidental appy may be the result
The number of reported cases in the US has increased in recent years
Rare complications include reactive arthritis and bacteremia
Salmonella
Rod shaped, Gram-negative, non spore forming
Always considered human pathogens
Most are motile
Normal flora of cattle, birds, and rodents
Cause enterocolitis (diarrhea) due to ingestion of contaminated food
The number of salmonella cases are few in the US
Salmonella
(continued)
Found in commercial meat, shell eggs, and unpasteurized milk
Cooking food at a high enough temp, for the correct period of time will kill the cells
Cutting boards and utensils used to cut uncooked meat can spread the bacteria
Hand washing and cleansing of cutting boards and utensils will prevent spreading the bacteria to other foods
Salmonella typhi
Cause the most sever infection:
Salmonella typhi
(continued)
Transmitted by the fecal-oral route
Not destroyed by macrophages and will multiply within them
Invades the Peyer’s patch and enters the lymphatic system then transported throughout the body by the circulatory system
The inflamatory response is initiated in the lungs, periosteum, and gallbladder
Salmonella typhi
(continued)
Hepatosplenomegaly occurs in many pts
Soon constipation then bloody diarrhea appears
After recovery the pt may carry and excrete S. typhi for a long period
A small percentage will become permanent carriers
Salmonella typhi
(continued)
Mary Mallon
The first documented permanent carrier of S. typhi
Caused several outbreaks and deaths before health officials caught up with her
Once caught she was isolated for life
What was her name changed to?
Salmonella typhi
(continued)
The cells persist in the gallbladder, common bile duct, hepatic duct, and cystic duct
Bile provides and excellent medium for growth
Antibiotics shorten the length of the illness
But most strains have become resistant
Anatomy of the gallbladder and ducts
Homework
Questions for further study
Page 179, # 1 and 2
Page 189, # 2
Chapter 14
Microbiology for Surgical Technologists
Haemophilus
Nonmotile
Gram-negative rods
Facultative anaerobe, but prefer an aerobic environment
Grow in pairs or short chains
Found in the mucous membranes of the respiratory and genital tracts of humans
Haemophilus
(continued)
Means blood-loving
Require one or two factors that are present in blood
Specifically heme (the old name is the “X” factor)
Contracted through droplet inhalation or sexual contact
Haemophilus influenzae
6 serotypes – a through f
Type b is most virulent
Virulence factors
Antiphagocytic
Peptidoglycan – in cell wall, damages the blood-brain barrier
Exotoxin – inhibits the movement of respiratory cilia
Fimbriae – aids cell adherence to tissue
Adhesins - aids cell adherence to tissue
Haemophilus influenzae
(continued)
Type b can spread from the respiratory tract to the sinuses and middle ear
It is the most common cause of septic arthritis and cellulitis in children 2 and under
Can lead to pneumonia and meningitis
Can be deadly in small children and elderly
Haemophilus influenzae
(continued)
Neurological conditions that can occur following recovery from H. influenzae meningitis are:
Hearing loss, blindness, chronic convulsions, hydrocephaly, and developmental disabilities
Since the introduction of the conjugated vaccine, the US has seen an almost 100% reduction in the incidence of H. influenzae type b
Haemophilus influenzae
(continued)
Treatment
Antibiotic therapy
Clinical trials are being done in infant to include dexamethasone (a steroidal anti-inflammatory drug).
It has been very successful in reducing meningeal swelling and the incidence of hearing loss
Haemophilus influenzae
biotype aegyptius
Causes pinkeye
A highly contagious purulent conjunctivitis
Infection can range from mild to severe
Mild – involving only the blood vessels of the eye
Severe – with lacrimation, swelling and photophobia
It can cause an even more severe form called Brazilian purpuric fever
Haemophilus ducreyi
Endemic in some parts of the world
High rates associated with poor socioeconomic and sanitary conditions
In the US it is common among crack addicts, prostitutes, and alcoholics
Causes chancroid
Sexually transmitted disease that manefests as soft chancres (ulcerations)
Haemophilus ducreyi
(continued)
Immunity does not develop after exposure
Treatment of choice is a new drug called azithromycin
Gram-Negative
Enteric Bacilli
Chapter 15
Microbiology for Surgical Technologists
Escherichia coli
The #1 cause of nosocomial infection
Gram-negative rod that grows singly
Part of the normal flora of the GI tract in humans
Help to prevent growth of pathogenic bacteris and synthesizes vitamins
Most strains are harmless
Can be the cause of endogenous infections
An infection caused by an organism that is normal flora
Escherichia coli
(continued)
Causes urinary tract infections, sepsis, diarrheal disease, and neonatal meningitis
Immuno-compromised or debilitated pts are at higher risk for infection
Four types of pathogenic strains
Enteropathogenic
Enterotoxigenic
Enterohemorrhagic
enteroinvasive
Escherichia coli
(continued)
Diarrhea
Enteropathigenic E. coli (EPEC)
Often the cause of diarrheal disease breakouts in nurseries
The microvilli in the intestinal tract are destroyed
Usually resolves in 5 to 15 days
Infants can quickly become dehydrated requiring intravenous fluid replacement
Escherichia coli
(continued)
Enterotoxigenic E. coli (ETEC)
Referred to as “traveler’s diarrhea”
Exotoxins that are produced are responsible for the symptoms
Individuals that live in countries with ETEC often have protective antibodies
Antibiotic therapy may be needed along with IV fluid replacement
Escherichia coli
(continued)
Enterohemorrhagic E. coli (EHEC)
Causes hemorrhagic colitis
Severe form of bloody diarrhea
Referred to as E. coli 0157:H7
Found in the intestines of healthy cattle
During the slaughtering and processing the microbes contaminate the beef
EHEC is acquired from ingesting raw or undercooked beef, unpasteurized milk, and other raw contaminated foods
Escherichia coli
(continued)
Enterohemorrhagic E. coli (EHEC) (continued)
Meat contaminated with EHEC looks and smells normal
Only a small number of cells can cause infection
Other methods of becoming infected include:
Swimming in or drinking sewage-contaminated water
Person to person contact
Bacteria in stools can be passed if proper hygiene habits are not practiced
Escherichia coli
(continued)
The CDC estimates that 20,000 become ill from EHEC annually and 250 die
It is also responsible for causing hemolytic uremic syndrome (HUS)
Can be fatal
HUS involves thrombocytopenia, acute renal failure, and gemolytic anemia
Thrombocytopenia is the decrease in the number of blood platelets
Escherichia coli
(continued)
Pts with HUS most likely require hemodialysis and blook transfusions
Most HUS pts are children 5 and under
Once symptoms appear antibiotic therapy is useless, and the disease must run it’s course
Those who survive often have chronic genitourinary complications due to kidney and urinary tract damage
Escherichia coli
(continued)
EHEC Virulence factors
Produces verotoxins that destroy the inner layer of blood vessels
Shiga-like toxin which aids the ability of the bacterial cell to adhere to tissue
Both toxins are identical to the toxin produced by Shigella dysenteriae
Escherichia coli
(continued)
Enteroinvative E. coli (EIEC)
Causes a type of dysentery similar to shegellosis, but not as virulent
Children are most susceptible
Is also common among travellers
Escherichia coli
Escherichia coli
(continued)
Urinary Tract Infections
(UTI)
Common infections in infants that are still in diapers, pts with indwelling catheters, and females
Responsible for the majority of nosocomial UTIs
Can cause pyelonephritis
Severe kidney infections
Escherichia coli
(continued)
UTI
(continued)
Caused by nephropathogenic E. coli (NPEC)
Has a capsule and pilus that add to virulence
Symptoms include side pain radiating to the back, dysuria, frequent urination, and hematuria
Escherichia coli
(continued)
E. coli is a common cause of meningitis in infants
Mortality rate is high
From 40% to 80%
The majority of those that survive will display neurologic deficits and/or develop mental abnormalties
It is rarely implicated as the cause of adult meningitis
Escherichia coli
(continued)
Treatment
In all cases, accept EHEC, antibiotic therapy is successful
Pts usually do not seek treatment for diarrhea unless they become dehydrated, individuals with a sudden onset of bloody stools should seek medical treatment immediately.
Klebsiella
Klebsiella pneumoniae
Causes approx 3% of community or nosocomial bacterial pneumonias
Tends to affect those who already have a disease such as diabetes, alcoholism, or COPD
The elderly are prone to developing lobar pneumonia
A hemorrhagic necrotizing consolidation of the lungs
Klebsiella pneumoniae
(continued)
The bacteria are responsible for the necrotic destruction of the alveoli, abscess formation in the lung, and production of sputum that is thick and red
Referred to as “currant jelly” sputum because of it’s appearance
Cells have a gelatinous capsule that inhibits phagocytosis
If not treated quickly it is often fatal
Klebsiella pneumoniae
(continued)
Causes empyema
Pus surrounding the lung
Causes irritation and scar formation
Chest x-rays reveal lung abscesses in advanced cases
Can also cause nosocomial UTIs, wound infections, and burn infections
Highly resistant to antibiotic therapy
Empyema
Yersinia
Three species important to the medical community
Yersinia pestis
Yersinia pseudotuberculosis
Yersinia enterocolitica
Yersinia pestis
Bubonic Plague
Also known as the
Black death
Yersinia pestis
(continued)
Responsible for some of the greatest epidemics in history
It eliminated approx 1/3 of the population of the world between 1348 and 1530
No one knows why that epidemic stopped
No major outbreaks have occurred in over a century
Likely due to improved pest control and insecticides
Yersinia pestis
(continued)
Humans contracted the disease from the bite of an infected rat flea
Upon infection the cell loses its capsular layer and most are destroyed by phagocytosis
A few will enter tissue that provide protection and resynthesize the capsule and other virulent agents
Yersinia pestis
(continued)
The infection quickly spreads to the lymph nodes
They become tender swollen, tender and hot
They then become hemorrhagic
Giving rise to the black colored buboes
Hence the name bubonic plague
The infection invades the blood and spreads to the spleen, liver, and lungs
The result is pneumonia with a productive cough filled with the pathogen, infecting the environment
The Plague
Cutaneous infection
The Plague
Inguinal Buboes
Yersinia pestis
(continued)
Death can occur within 24 hours of the initial signs of infection
There are few drug resistant strains
Control measures have centered on the elimination of the rat flea
It is highly unlikely that it will ever be eradicated
Yersinia pseudotuberculosis
A pathogen of rodents and bird, but can infect humans
Is distinguished among other Yersinia species because it is motile
Produces large nodules in the Peyer’s patch and mesenteric lymph nodes
The Peyer’s patch is a group of lymph node located at the terminal ilial junction
May cause abscesses and require intestinal resection with anastomosis
Yersinia enterocolitica
A pathogen of cattle, pigs, deer, and birds
Excreted in the feces and can contaminate dairy products and drinking water
Humans can become infected by eating raw or undercooked pork products
The disease is called yersiniosis
Causes severe diarrhea with necrosis of the Peyer’s patch, liver and splenic abscesses, and chronic lymphadenopathy (swelling of the lymph nodes
Yersinia enterocolitica
(continued)
Often confused with appendicitis because of the right lower quadrant pain
An incidental appy may be the result
The number of reported cases in the US has increased in recent years
Rare complications include reactive arthritis and bacteremia
Salmonella
Rod shaped, Gram-negative, non spore forming
Always considered human pathogens
Most are motile
Normal flora of cattle, birds, and rodents
Cause enterocolitis (diarrhea) due to ingestion of contaminated food
The number of salmonella cases are few in the US
Salmonella
(continued)
Found in commercial meat, shell eggs, and unpasteurized milk
Cooking food at a high enough temp, for the correct period of time will kill the cells
Cutting boards and utensils used to cut uncooked meat can spread the bacteria
Hand washing and cleansing of cutting boards and utensils will prevent spreading the bacteria to other foods
Salmonella typhi
Cause the most sever infection:
Salmonella typhi
(continued)
Transmitted by the fecal-oral route
Not destroyed by macrophages and will multiply within them
Invades the Peyer’s patch and enters the lymphatic system then transported throughout the body by the circulatory system
The inflamatory response is initiated in the lungs, periosteum, and gallbladder
Salmonella typhi
(continued)
Hepatosplenomegaly occurs in many pts
Soon constipation then bloody diarrhea appears
After recovery the pt may carry and excrete S. typhi for a long period
A small percentage will become permanent carriers
Salmonella typhi
(continued)
Mary Mallon
The first documented permanent carrier of S. typhi
Caused several outbreaks and deaths before health officials caught up with her
Once caught she was isolated for life
What was her name changed to?
Salmonella typhi
(continued)
The cells persist in the gallbladder, common bile duct, hepatic duct, and cystic duct
Bile provides and excellent medium for growth
Antibiotics shorten the length of the illness
But most strains have become resistant
Anatomy of the gallbladder and ducts
Homework
Questions for further study
Page 179, # 1 and 2
Page 189, # 2
posted by Ms. Carpenter | 11:27 AM
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