Neisseria/other G- bacilli

Neisseria
And Aerobic Gram-negative Cocci

Microbiology for Surgical Technologists
Chapter 12
Neisseriaceae
Gram-negative
Aerobic
Consists of ten species, two of which are human pathogens
Virulence factors
Both have pili, allows them to move through tissue and are not easily removed
They are encapsulated
Neisseria gonorrhoeae
Gonorrhea
Also called the clap or the drips

Fastidious, gram-negative diplococcus
Reached epidemic status in US
Due to a promiscuous, mobile society
The use of birth control in women changes the microbial environment of the vagina, making them more susceptible to the disease
Due to careless use of PCN, it has mutated into resistant strains known as penicillinase-producing N. gonorrgoeae (PPNG)
An estimation of 80% women and 20% men are asymptomatic
Attaches to the epithelial cells of the GU tract, rectum, and throat
Then passes to the sub-epithelial space and becomes established
Initial phase can last several months and damage and scar reproductive organs
Symptoms then appears as localized pain
Infections in males occur primarily in the urethra
Displays with a urethral discharge and dysuria (painful urination)
Primary site of infection in females is the cervix
It cannot infect the epithelial cells of the vagina
Displays symptoms of dysuria, abdominal pain and vaginal discharge
A serious complication in women is Pelvic Inflammatory Disease (PID)
An acute infection of the abdomen
Can cause salpingitis ( infection of the fallopian tubes
If left untreated, can cause sterility due to scarring and adhesions
Can be contracted orally and present as only a sore throat for a short duration
Can be passed to fetus at birth
Treatment
CDC remommends ceftiaxone, cefixime, ciprofloxacin for uncomplicated cases
In patients with dual infections with chlamydia, one of the above is combined with doxycyline or azithromycin
Neisseria meningitidis
An encapsulated, Gram-negative diplococci
Only found in humans
Colonizes the nasopharynx
Second most common cause of community-acquired meningitis in adults
If untreated, mortality rate is 100%
When the bacteria invade the bloodstream through the nasopharynx epithelium it is Meningococcemia
Pt can have it with or without meningitis
Life threatening
Symptoms include skin lesions and petechial skin patches
The petechial skin patches will combine to form larger hemorrhagic lesions
Acute fulminating meningococcemia (Waterhouse-Friderichsen syndrome) a serious disease that involves multiorgan systems of the body
Has a high mortality rate
In just a few hours the pt becomes restless, apprehensive, and delirious
Petechial patches appear all over the body with no signs of meningitis
Results in disseminated intravascular coagulation (DIC), and shock
DIC is a condition where the pts blood will no longer clot properly
An extreme emergency in surgical pts
Majority of pts expire within 24 hours despite treatment
A vaccine has been developed
Only used for military personel and in hyperendemic* regions of the world
A region that has epidemics that are cyclic
Transmitted through respiratory droplets
Most common during dry months
In US causes endemic outbreaks and seldom causes epidemics
The sub-Saharan area of Africa is referred to as the “meningitis belt”
Epidemics occur every ten years
Moraxella
Gram-negative, nonmotile, cocci
Strictly aerobic
Are coccobacilli
Their shape is between a cocci and rods
Moraxella lacunata
Colonizes the eyes
Is thought to be a cause of conjunctivitis in humans
Moraxella catarrhalis
Common cause of otitis media in children, adult sinusitis, bronchitis, and bronchopneumonia
The elderly with chronic obstructive pulmonary disease (COPD) are very susceptible
Is resistant to PCN, but cephalosporins, erythromycin, tetracycline, ampicillin, and sulfa drugs are effective
Moraxella catarrhalis
Estimated to be normal flora in 40% to 50% of school age children
The third most common cause of otitis media
The third most common cause of sinusitis in adults
Pts with COPD will often develop emphysema and chronic bronchitis which leads to life threatening pneumonia
Other Gram-negative Bacilli and Coccobacilli
Chapter 13

Microbiology for Surgical Technologists
Pasteurellaceae
Gram-negative
Nonmotile
Nonspore forming
Either aerobic or facultative anaerobic
Pasteurella
Named after Louis Pasteur
Are pleomorphic
Range from bacilli to cocci
Facultative anaerobic
Infection transmitted to humans from animals through an opening in the skin or from a bite
Pasteurella multocida
Four forms of the infection
Localized
Cellulitis, lymphdenitis, and pain from the bite
Respiratory
Increased pulmonary complication with pts that already have pulmonary disease
Septicemia
Spreads either through circulatory system or lymphatic system
Endocarditis

Pasteurella multocida
(continued)
Domestic animals harbor the bacteria in their respiratory tract
Pass it on to humans through bites and scratches
Domestic animal bites are responsible for 1% of all emergency room admission
If not cleaned and treated can result in serious infection.
Pasteurella multocida
(continued)
Virulence factors
Antiphagocytotic capsule
Endotoxin that contributes to tissue damage and chronic abscesses
Lab cultures emit a foul odor
Easily treated with antibiotics
Brucella
Nonmotile, Gram-negative, nonencapsulated coccobacilli
Four of the six species are human pathogens and cause brucellosis
Named for the animal in which it is commonly found:
B. abortus (cattle)
B. canis (dogs)
B. melitensis
B. suis (swine)
Brucella
(continued
Virulence
Resistant to phagocytosis
The phagocytes take the bacteria in and then they are transported to the kidneys, spleen, lymph nodes, and bone marrow
Cause granulomas in these structures and will destroy the organ tissue
Result from the consumption of unpasteurized milk and dairy products
Brucella
(continued
Of the 100 to 200 cases reported in the US annually, most are from Texas and California
Can also occur from direct contact with animals or through infectious aerosols
Other routes of infection are breast milk and sexual contact with an infected person
Incidence is low now due to vaccination and destruction of infected animals
Brucella
(continued
Dogs and cows produce a mild form of the disease
Swine and goats produce the more severe form
Produces undulant fever
Intermittent fever
In severe cases recovery can take a few weeks to several months
Bordetella
Gram-negative, strickly aerobic coccobacilli
Virulence:
Surface protein on the cell wall called filamentous hemagglutinin
Aids in the ability of the organism to adhere to the cilia of the respiratory tract
Secretion of pertussis toxin
An exotoxin that increases the release of histamine
Bordetella
(continued)
Virulence (continued)
Secretion of adenylate cyclase
A compound that inhibits phagocytosis
Tracheal cytotoxin
An exotoxin that destroys the tissue of the respiratory tract
Bordetella pertussis
Whooping
Cough
Bordetella pertussis
(continued)
Acquired by inhaling the cough droplets of an infected person
Highly communicable
In 1934 265,000 cases were reported
5 of every 1000 children died
Once the vaccine was developed the cases dramatically decreased
Bordetella pertussis
(continued)
Three stages of the disease
Prodromal stage
Begins with nonspecific cold-like symptoms that progress to a cough
Paroxysmal stage
Frequent, violent coughing attacks that cause the patient to gasp for breath
Resulting in the characteristic sound for which the disease is named for
Convalescent stage
Resolution of symptoms and disease
Bordetella pertussis
(continued)
The bacteria attach to the cilia of the respiratory tract and prevent their movement and progressively destroy them
This prevents the mucous that collects to be swept forward and eliminated
The patient attempts to cough up the mucous, with increased violence of the coughing spells
Bordetella pertussis
(continued)
Complications
Occur during second stage (paroxysmal)
Broken ribs (especially in children)
Inguinal hernia (primarily in men)
Rectal prolapse
Severe difficulty breathing requiring intubation and ventilation
Otitis media in children
Bordetella pertussis
(continued)
A culture is obtained by placing a swab, on the end of a wire, through the nose into the nasopharyngeal tract and left in place while the pt coughs
A more recent method is with aspiration of the nasopharyngeal tract
Bordetella pertussis
(continued)
Treatment
Erythromycin is given, but only to lessen symptoms by destroying some of the organisms
By the time pertussis is diagnosed the toxins have already caused extensive damage
Supportive measures are taken, but the disease has to run it’s course
Bordetella pertussis
(continued)
Treatment
(continued)
Convalescence depends on the cilia’s ability to regenerate
The most effective treatment is prevention with the vaccine (DPT)
Pts who have had the disease will develop immunity for a number of years

Gardnerella vaginalis
Non-motile
Non-spore forming
Non-capsulated
Facultative anaerobe
The cell wall allows adherance to epithelial cells
Normal vaginal flora in 50% to 70% of women
Gardnerella vaginalis
(continued)
The pathogenic role of the organism causes vaginosis
Since inflammation is not present, the term vaginosis is used instead of vaginitis
Can be transmitted sexually
Although men are only carriers and show no sign of disease
Increases the normal pH level of the vagina
Changes the normal environment throwing the balance off
Gardnerella vaginalis
(continued)
Risk factors for developing vaginosis
Invasive procedures
Hysterectomy, endometrial biopsy, and implantation of IUD
Change in sexual partners
Menopause
Diabetes
Immunocompromised pts
Poor hygiene
Gardnerella vaginalis
(continued)
Can cause
Postpartum bacteremia, postpartum endometriosis, premature birth, low birth weight, and neonatal septicemia
Symptoms
Copious gray-white discharge with a foul “fish-like” smell
Caused by amines putrescine and cadaverine, found in rotting fish
Gardnerella vaginalis
(continued)
Standard treatment is the antibiotic Flagyl
Kills the anaerobes and allows the normal lactobacilli to multiply back to their normal population and decreasing pH