Microbiology - Block 3 - Part 2

davidwurbel7's version from 2015-07-20 13:59

Bordetella pertussis

Question Answer
Gram negative coccobaccilus, strict aerobe. Transmission - Inhalation respiratory droplets. Infects ciliated respiratory epithelium. Reservoir - infected humans with mild disease. Those a risk - Unvaccinated (children & adults). Severest disease – unvaccinated infantsBordetella pertussis
Virulence factors include filamentous hemagglutinin. Adenylate cyclase toxin which increases in cAMP, increasing respiratory secretions and impairing leukocyte chemotaxis. Inhibits phagocytosis. Tracheal cytotoxin. Pertussis toxinBordetella pertussis
A-B component toxin composed of outer membrane proteins. Promotes lymphocytosisPertussis Toxin
For everyone 11 years and older, including pregnant womenTdap
For children 2 months through 6 years of ageDTaP
Immunity in vaccinated individuals does this over time causing persons infected later in live to develop a milder form of the diseaseWanes
Lasts 1-2 weeks. Mild upper respiratory tract infection – sneezing, mild cough, low fever, runny nosePertussis - Catarrhal Phase
Lasts 1-6 weeks. Extends to lower respiratory tract. Severe cough (5-20 forced hacking coughs ("machine-gun cough") followed by a stridor upon inspiration). Apnea (pause in breathing) – in infants. Anoxia and vomitting may occur. Complications may arisePertussis Paroxysmal Phase
Cough fits gradually decrease in length and intensity. Coughing fits may return with other resp. infections for many months after pertussis startedPertussis Convalescent Phase
Pneumonia, Apnea, Convulsions, Neurological damage (in infants might be permanent). 1-2% deaths (unvaccinated infants)Pertussis Complications
Nasopharyngeal cultures are plated on this medium to which charcoal has been addedBordet-Genou Medium / Regan-Lowe Medium
Pertussis is treated withErythromycin/TMP-SMX
Expectant mothers - should receive vaccine during each pregnancy at this point in the pregnancy27-36 Weeks


Question Answer
Small gram negative rods poorly staining. Facultative intracellular. Grown on buffered charcoal yeast extract medium (BCYE). Reservoir - WATER. Air-conditioning cooling towers. Hot water heaters. Hot-tubs. Grocery store produce sprayers. Transmission by bacteria in aerosolized water.Legionella pneumophila
Individuals over 55 years who smoke and drink alcohol. Elderly debilitated. Chronic lung disease, immunocompromisedHigh Risk Group for Legionella
Legionella is able to infect and replicates inside this cell. Inhibits phagolysosome fusionMacrophages
Legionella poduces proteolytic enzymes that kill host cell when vacuole is lysed. Legionella injects the proteins into the cytosol by this systemDOT Type 4 Secretion System (T4SS)
Immunity and immune response depends heavily on this immune response to clear the bacteria from the bodyCell-Mediated Immunity
Disease seen in immunosuppressed patients eg, renal transplant recipients. Smokers over 55 yrs with high alcohol intakeLegionnaire’s disease
Mild infection of otherwise healthy individuals with LegionellaPontiac Fever
Atypical pneumonia. Acute lobar pneumonia + major confusion + diarrhea. Dry, non-productive cough. Gram stain of sputum – neutrophils but no bacteriaLegionnaire's Disease
Self-limited febrile disease. No pulmonary involvement. Fever, chills, myalgias, malaise, headache. Resolves spontaneously after 2-5 days. No treatment usually necessaryPontiac Fever
Legionella antigen can be detected in thisUrine
Legionella is treated with this class of antibioticMacrolides (Azithromycin, Clarithromycin)

GNB Enterobacteriaceae

Question Answer
Commensal bacteria colonize the GI tractMicrobiota
A predominant population in addition to Firmicutes and BacteroidesEnterobacteriaceae
Gram (-) Bacilli/Rods. Facultative anaerobe. Catalase (+). Oxidase (-). Glucose metabolism. Non-fastidious. Growth factor sequestration ex. iron. Lactose fermentation variable. Motility and capsule variable. Antibiotic Resistance plasmidsEnterobacteriaceae
Treatment for systemic EnterobacteriaceaeCiprofloxacin
Treatment for non-systemic EnterobacteriaceaeSymptom Management
Serve as indicators for fecal contamination of waterColiforms
Transmission requires change in host statusEndogenous
Fecal-oral transmissionExogenous
Large family. Responsible for wide variety of clinical diseases. Resistant to many antibiotics. Sensitive to drying. Shared biology and virulence factors. Pink on MacConkey agarEnterobacteriaceae
NMECNeonatal Meningitis E. coli
UPECUro-Pathogenic E. Coli
Too much TNF αSeptic Shock
Serotyping against FlagellaH
Serotyping against CapsuleV or K
Serotyping against LPS sugar residueO
E.coli O157:H7EHEC
E.coli K1NMEC
Prevents binding to C3bR (CR1), thus bacteria cannot be phagocytosedPolysaccharide Capsule
Capsulated bacteria are strongly associated with these types of infectionsSystemic and Menigial Infections
Needle mechanism to directly inject effector molecules into host cellType 3 Secretion System T3SS
Neonatal meningitisE.Coli K1 (NMEC)
UTI/systemicUropathogenic E.Coli (UPEC)
UTI/Kidney stonesProteus
Gram Negative Bacilli. Lactose Fermenter. Encapsulated K-1. Gram stain of CSF. CSF -> Cloudy, PMNs, low glucose, high proteinNeonatal Meningitis E.coli (NMEC)
Treatment for Neonatal Meningitis E.coli (NMEC)Cefotaxime
Gram Negative Bacilli. Lactose Fermenter. Reduce Nitrate to Nitrite. Normal colon flora->gain access to urethraUroPathogenic E.coli UPEC
Nosocomial infection is most likely fromCatheters
Community-acquired infection is most likely fromHygiene
Low grade fever, dysuriaUTI/Cystitis
High fever, dysuria, low flank pain, most of time hematuriaPyelonephritis
Bacteria uses these for attachment to uro-epithelial cells and biofilm is formedFimbriae & Pili
Based on urinalysis, treatment isTMP-SMX or Ciprofloxacin or Antibiotic Susceptibility Panel
Uncomplicated UTI with most infections being caused by UPEC and are mild infections. DOCCotrimoxazole
Complicated UTI. Most infections are recurrent and patient has underlying health conditions. Patient is at risk for developing sepsis. If UPEC develops resistance to TMP-SMX use thisCiprofloxacin
The presence of this in a urinalysis is diagnostic of a UTI with UPECNitrite
Gram Negative Bacilli. Lactose Non-Fermenter. Urease (+). Swarming Motility. Urease reduces urea->ammonia-> Struvite kidney stones.Proteus
Gram Negative Bacilli. Lactose Fermenter. Purple Mucoid. Encapsulated. Alcoholics prone to pneumonia.Klebsiella pneumonia
Carbepenem-Resistance (CRKP) is major health threatKlebsiella pneumonia
Alcoholics and homeless patients. Usually aspiration-associated. “Current grape jelly” purple viscous sputumCommunity-Acquired Lobar Pneumonia
Possess multiple drug resistance mechanisms. Plasmid-encoded carbapenase is a B-lactamase that degrades all B-lactamsCarbepenase-Resistant Klebsiella (CRKP)
Gram Negative Bacilli. Lactose Fermenter. Red prodigiosin-pigment. Can present with UTI, Pneumonia, Sepsis->Meningitis, Osteomyelitis. Treatment is with CiprofloxacinSerratia marcescens

Pathogenic Enterobacteriaceae

Question Answer
Watery diarrhea (vomiting variable). Onset 6-18 hrs and resolution 2 days. Absence of fever. Lesser severity of symptoms for viralViral Gastroenteritits
Vomiting + Watery diarrhea. Onset 3-12 hrs and resolution 2 days. Absence of fever. Toxin-mediatedBacterial Food Poisoning
Watery or bloody diarrhea. Onset 24-48 hrs and resolution ~7 days. Fever (invasive) or no fever (non-invasive). Dependent on Colonization. More severe symptoms (pain)Bacteria Diarrhea
No fever with profuse watery diarrhea is a result of thisExotoxin
No fever with profuse watery diarrhea due to exotoxin is caused byCholera
No fever with profuse bloody diarrhea due to exotoxin is caused byShigella
Inflammation, as defined by the presence of neutrophils, of small intestine/colon, high volume watery diarrhea with possible presence of RBC and WBCGastroenteritis/Colitis
Infection of colon, tenesmus, significant pus/RBC/WBC and low volume diarrheaDysentery
Profuse blood due to damage to blood vessels from exo-toxinHemorrhagic
Bacterial colonization of spleen and liverTyphoid
Viable bacteria in bloodBacteremia
Bacteremia with sepsis (High TNF-a)Septicemia
“Rice-water” diarrheaETEC
Watery diarrheaEPEC
Grossly bloody diarrheaEHEC
Self-resolving Profuse Watery Secretory Diarrhea without fever. Most common of diarrhea in travelers. Very common in developing countriesEntero-Toxigenic E. coli (ETEC)
Activates guanylate cyclase, increasing cGMPST Toxin (Heat-Stable)
A/B toxin similar to Cholera toxin. GPCR is activated via Gαs thus activating adenylyl cyclaseLT (Heat-Labile)
Invasive diarrhea, found in developing countries. Low-volume bloody stools, WBC present with high fever (Dysentery)Entero-Invasive E. coli (EIEC)
Mostly seeing in babies and in developing countries. Most common cause pediatric diarrhea. Self-resolving Secretory Watery Diarrhea without feverEntero-Pathogenic E. coli (EPEC)
Attaches to small intestinal cells via T3SS system actin pedestal formation calledAttaching and Effacing (A/E) Lesions
Watery Diarrhea followed by profuse bloody diarrhea without fever or WBCs. Hemorrhaging diarrhea. Form A/E lesions similar to EPEC which cause initial watery diarrhea symptoms. Shiga-toxin destroys endothelial cells which causes bloody diarrhea symptomsEnteroHemorrhagic E.coli (EHEC)
EHEC, Serotype that can cause profuse bloody diarrheaEHEC O157:H7
The hemorrhaging is caused by this being secreted by EPECShiga Toxin
An A/B toxin that attaches to receptors on intestinal villi and renal endothelial cells. Targets the 28s RNA ribosome subcomponent of the 60s ribosome subunit. Destruction of endothelial cells results in hemorrhagingShiga Toxin
Fever. Acute renal failure (fever, hypertension, dry skin, rash). Thrombocytopenia. Microangiopathic hemolytic anemia (Hb decreased). Neurological manifestations. More common in <5 yrs oldHemolytic Uremic Syndrome
EHEC yields white colonies on this agarSorbitol-MacConkey Agar
Treatment for ETEC, EIEC, EPEC and EHECSupportive (Rehydration Therapy)