p.17
Identification of Gram Positive Organisms
What are Gram positive cocci that form clusters?
Staphylococcus and Micrococcus.
p.39
Identification of Gram Positive Organisms
How sensitive is S. pyogenes to bacitracin?
S. pyogenes is sensitive to bacitracin.
p.43
Identification of Gram Positive Organisms
What does CAMP stand for?
Christie, Atkins, Munch-Petersen.
p.53
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What type of exposure increases the risk of VRE colonization?
Proximity to other patients who are colonized with VRE, especially those with diarrhea.
p.15
Identification of Gram Positive Organisms
Are anaerobic Gram positive organisms covered in this lecture?
No, they are not covered.
p.34
Streptococcus Identification and Clinical Relevance
What is the primary method used for identifying Streptococcus and Enterococcus?
A simplified identification scheme.
p.57
Gram Positive Rods/Bacilli and Their Clinical Importance
What can Gram positive rod isolates from clinical specimens indicate?
They may be clinically significant or contaminants.
p.10
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
In which journal was the article published?
Clinical Microbiology Reviews.
p.39
Identification of Gram Positive Organisms
What is the purpose of the Bacitracin test?
To screen for S. pyogenes.
p.53
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What factors influence the risk of acquiring VRE?
Risk depends on exposure to VRE and being a susceptible host.
p.2
Bacterial Cell Shape and Arrangement
What are the common shapes of bacterial cells?
Cocci (spherical), bacilli (rod-shaped), and spirilla (spiral-shaped).
p.42
Identification of Gram Positive Organisms
What is the classification of Streptococcus agalactiae?
Group B Streptococcus (GBS).
p.50
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What does VRE stand for?
Vancomycin-Resistant Enterococcus.
p.36
Clinical Significance of Staphylococcus Species
What are the treatments for infections caused by Streptococcus pneumoniae?
Penicillin and cefotaxime.
p.50
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What is the prevalence of VRE in Canada?
VRE has been reported in various healthcare facilities across Canada.
p.13
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What score value indicates that an organism can be reported to the genus and species level?
A score value greater than 2.00.
p.34
Streptococcus Identification and Clinical Relevance
What biochemical tests are commonly used in the identification scheme?
Catalase test, bile esculin test, and growth in 6.5% NaCl.
p.25
Methicillin-Resistant Staphylococcus aureus (MRSA)
What does mecA gene expression alter?
Penicillin binding protein 2 (PBP2) production.
p.11
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What is the main focus of the article by Van Belkum et al. (2017)?
Matrix-assisted laser desorption ionization time-of-flight mass spectrometry in clinical microbiology.
p.49
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
When was VRE first reported?
In 1986 in France and the UK.
p.11
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What type of publication is the article by Van Belkum et al.?
It is a journal article published in the Annals of Laboratory Medicine.
p.13
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What should any score from MALDI-TOF be correlated with?
Gram stain and culture characteristics, clinical context, and biochemical features.
p.15
Gram Positive Rods/Bacilli and Their Clinical Importance
List some examples of Gram positive rods/bacilli.
Bacillus, Corynebacterium, Lactobacillus, Mycobacterium tuberculosis, Actinomyces.
p.12
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
How is the final Bruker MALDI-TOF score calculated?
The three values are multiplied together, normalized to 1000, and then the base 10 logarithm is taken.
p.57
Gram Positive Rods/Bacilli and Their Clinical Importance
What are Gram positive rods/bacilli?
A diverse group of bacteria.
p.23
Methicillin-Resistant Staphylococcus aureus (MRSA)
What is MRSA?
Methicillin-Resistant Staphylococcus aureus, a strain resistant to methicillin and other antibiotics.
p.43
Identification of Gram Positive Organisms
What is the clinical significance of the CAMP test?
It can be used to screen for S. agalactiae.
p.23
Methicillin-Resistant Staphylococcus aureus (MRSA)
What are the implications of drug-resistant S. aureus?
Increased difficulty in treating infections and higher healthcare costs.
p.10
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What significant change does MALDI-TOF Mass Spectrometry represent in clinical microbiology?
A fundamental shift in routine practice.
p.34
Streptococcus Identification and Clinical Relevance
What are the key characteristics used in the identification of Streptococcus?
Hemolysis patterns, Lancefield classification, and biochemical tests.
p.50
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
How is VRE transmitted?
Through direct contact with contaminated surfaces or infected individuals.
p.66
Gram Positive Rods/Bacilli and Their Clinical Importance
Where is Actinomyces commonly found in the human body?
Skin, mouth, gut, and vagina.
p.35
Streptococcus Identification and Clinical Relevance
What is the shape and arrangement of Streptococcus pneumoniae?
Gram-positive diplococci or in short chains.
p.65
Gram Positive Rods/Bacilli and Their Clinical Importance
Where can Erysipelothrix be found?
In soil, water, and the digestive tract of many animals.
p.17
Identification of Gram Positive Organisms
Which Gram positive cocci are found in chains?
Streptococcus and Enterococcus.
p.15
Identification of Gram Positive Organisms
Name four examples of Gram positive cocci.
Staphylococcus, Micrococcus, Streptococcus, Enterococcus.
p.41
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What is a key feature of Streptococcus that helps it evade the immune system?
A capsule composed of hyaluronic acid to prevent phagocytosis.
p.14
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What is VITEK MS?
A mass spectrometry system developed by bioMérieux for microbial identification.
p.14
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What is the primary purpose of VITEK MS?
To identify microorganisms quickly and accurately.
p.34
Streptococcus Identification and Clinical Relevance
Why is a simplified identification scheme important?
It aids in the quick and accurate identification of these bacteria.
p.57
Gram Positive Rods/Bacilli and Their Clinical Importance
What should be correlated for assessing clinical significance of Gram positive rods?
Specimen types, clinical information, and clinical significance.
p.40
Identification of Gram Positive Organisms
What is the appearance of Streptococcus pyogenes colonies?
Large (>0.5 mm), grey, translucent colonies with a wide zone of β-haemolysis.
p.13
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What score value allows reporting to the genus level only?
A score value between 1.70 and 2.00.
p.62
Bacterial Cell Shape and Arrangement
What is the shape of Corynebacterium?
Pleomorphic Gram positive rods with V-shaped or Chinese characters shape.
p.19
Coagulase-Positive and Coagulase-Negative Staphylococci
What is the primary function of the coagulase test?
To convert fibrinogen to fibrin and induce clotting.
p.41
Clinical Significance of Staphylococcus Species
What are some clinical conditions caused by Streptococcus?
Pharyngitis, sore throat, tonsillitis, scarlet fever, wound infections, and necrotizing fasciitis.
p.51
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What type of cases have been reported in Hong Kong regarding VRE?
Sporadic cases of colonization or infections and limited outbreaks.
p.44
Clinical Significance of Staphylococcus Species
When should pregnant women be screened for GBS?
At 35 to 37 weeks gestation.
p.2
Bacterial Cell Arrangement
What is the arrangement of cocci bacteria?
They can be found in clusters (staphylococci), chains (streptococci), or pairs (diplococci).
p.63
Bacterial Cell Shape and Arrangement
What is the shape and arrangement of Lactobacillus?
Long and filamentous rods in chains, no spore.
p.34
Streptococcus Identification and Clinical Relevance
What type of bacteria does the identification scheme focus on?
Streptococcus and Enterococcus.
p.22
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What types of toxins do certain bacteria produce to evade host defenses?
Cytolytic toxins, haemolysins, and leukotoxins.
p.27
Methicillin-Resistant Staphylococcus aureus (MRSA)
What is SCC mec in the context of bacterial diagnosis?
A genetic element detected by PCR.
p.25
Methicillin-Resistant Staphylococcus aureus (MRSA)
What is the staphylococcal cassette chromosome mec (SCC mec)?
A genomic region inserted into the Staphylococcal genome.
p.2
Bacterial Cell Shape and Arrangement
What is the significance of bacterial cell shape and arrangement?
It helps in the identification and classification of bacteria.
p.54
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What are the consequences of VRE colonization?
Increased mortality, longer hospital stays, ICU admissions, surgical procedures, and costs.
p.25
Methicillin-Resistant Staphylococcus aureus (MRSA)
Where is it likely that SCC mec originated?
In coagulase-negative staphylococcal species.
p.52
Methicillin-Resistant Staphylococcus aureus (MRSA)
What does the van C gene indicate?
Intermediately resistant to vancomycin (e.g., 8 – 16 μg/mL) but sensitive to teicoplanin, and is chromosome-borne.
p.48
Clinical Significance of Staphylococcus Species
What infections are associated with Enterococcus species?
Bacteraemia, endocarditis, wound and soft tissue infections.
p.25
Methicillin-Resistant Staphylococcus aureus (MRSA)
What is the function of the ccr gene?
It facilitates the attachment of SCC mec cassette to the staphylococcal chromosome.
p.59
Bacterial Cell Shape and Arrangement
What is the shape and Gram reaction of Bacillus species?
Large Gram-positive straight-edged rods.
p.9
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What does MALDI-TOF stand for?
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight.
p.24
Methicillin-Resistant Staphylococcus aureus (MRSA)
What does MRSA stand for?
Methicillin-resistant Staphylococcus aureus.
p.44
Clinical Significance of Staphylococcus Species
What serious conditions is GBS associated with in neonates?
Stillbirth, meningitis, septicemia, and pneumonia.
p.44
Clinical Significance of Staphylococcus Species
What postpartum infections can GBS cause in pregnant women?
Bacteremia and endometritis.
p.23
Methicillin-Resistant Staphylococcus aureus (MRSA)
What does drug resistance in S. aureus refer to?
The ability of S. aureus to survive despite the presence of antibiotics.
p.36
Clinical Significance of Staphylococcus Species
What invasive diseases can Streptococcus pneumoniae cause?
Otitis media, sinusitis, and meningitis.
p.36
Clinical Significance of Staphylococcus Species
What are some occasional infections caused by Streptococcus pneumoniae?
Endocarditis, septic arthritis, peritonitis, pericarditis, osteomyelitis, and soft tissue infections.
p.38
Streptococcus Identification and Clinical Relevance
How are β-haemolytic Streptococcus classified?
According to Lancefield grouping.
p.14
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What advantage does VITEK MS provide in microbiology?
Rapid identification of microbial species.
p.8
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What does the mass spectral fingerprint in MALDI-TOF represent?
Desorbed microbial cell components, mainly intracellular proteins.
p.26
Methicillin-Resistant Staphylococcus aureus (MRSA)
What does HA-MRSA stand for?
Hospital-associated Methicillin-Resistant Staphylococcus aureus.
p.63
Clinical Significance of Staphylococcus Species
What role does Lactobacillus play in the female genital tract?
Maintaining the acidic environment needed for healthy vagina flora.
p.6
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What is the purpose of the matrix in MALDI-TOF?
To entrap and co-crystallize the sample for analysis.
p.8
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What variations can be observed in the mass spectrum among bacteria?
Differences among genera, species, or some strains.
p.20
Identification of Gram Positive Organisms
What type of bacteria is Staphylococcus aureus?
Gram-positive cocci in 'grape-like' clusters.
p.54
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
How long can VRE persist in the gastrointestinal tract?
From 3 months to 2 years.
p.59
Gram Positive Rods/Bacilli and Their Clinical Importance
Which Bacillus species are clinically important?
B. anthracis and B. cereus.
p.47
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
Which two species are common in the Enterococcus genus?
E. faecalis and E. faecium.
p.7
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
How is an ion's mass-to-charge ratio determined in MALDI-TOF?
By a time of flight measurement.
p.37
Streptococcus Identification and Clinical Relevance
Describe the colony characteristics of Viridans Streptococcus.
Tiny, small, grey, smooth, or dull colony.
p.12
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What does the Bruker MALDI-TOF score represent?
The probability of isolate identification.
p.16
Identification of Gram Positive Organisms
Where are Gram positive cocci typically found as normal flora?
In most body sites covered with skin or lined with mucous membranes.
p.36
Clinical Significance of Staphylococcus Species
What is the most common cause of community-acquired pneumonia?
Streptococcus pneumoniae.
p.57
Gram Positive Rods/Bacilli and Their Clinical Importance
What are the most common isolates of Gram positive rods?
Bacillus, Corynebacterium, Lactobacillus.
p.57
Gram Positive Rods/Bacilli and Their Clinical Importance
Why is Gram stain morphology important?
It is useful for initial classification.
p.42
Identification of Gram Positive Organisms
What type of hemolysis is typically associated with Streptococcus agalactiae?
Narrow zone of β-haemolytic; some strains are γ-haemolytic.
p.32
Identification of Gram Positive Organisms
What is the shape and arrangement of Micrococcus?
Gram positive cocci in tetrads.
p.22
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What is Protein A and its function?
A surface protein that binds the Fc region of immunoglobulin G (IgG) antibody.
p.66
Gram Positive Rods/Bacilli and Their Clinical Importance
What type of bacteria is Actinomyces?
Branched Gram positive rods.
p.50
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What measures are taken to control VRE in hospitals?
Infection control practices, including hand hygiene and isolation of infected patients.
p.40
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What are the two haemolysins produced by Streptococcus pyogenes?
Streptolysin S (stable in oxygen) and Streptolysin O (labile in oxygen).
p.13
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What does a score value less than 1.7 indicate?
No organism identification is possible.
p.47
Identification of Gram Positive Organisms
What is the appearance of Enterococcus colonies?
Small grey-white colonies.
p.6
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What happens during the laser desorption step in MALDI-TOF?
The matrix absorbs laser energy, converting it to heat, which triggers vaporization and desorption of the sample.
p.26
Methicillin-Resistant Staphylococcus aureus (MRSA)
When was CA-MRSA first reported?
In the 1990s in Australia, New Zealand, and America.
p.65
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What disease does Erysipelothrix cause?
Erysipeloid, an erythematous edema.
p.35
Streptococcus Identification and Clinical Relevance
What are the characteristics of the colonies of Streptococcus pneumoniae?
Small, grey, may be mucoid, dry, or umbilicated.
p.4
Bacterial Cell Shape and Arrangement
What does the arrangement of cocci refer to?
The specific grouping or clustering of spherical bacteria.
p.17
Identification of Gram Positive Organisms
Which Gram positive cocci are typically found in pairs?
Streptococcus pneumoniae.
p.15
Identification of Gram Positive Organisms
What are the main types of Gram positive organisms?
Gram positive cocci and Gram positive rods/bacilli.
p.24
Methicillin-Resistant Staphylococcus aureus (MRSA)
Where was MRSA originally localized?
In hospital environments.
p.43
Identification of Gram Positive Organisms
What effect does the CAMP factor have on haemolysis?
It enlarges the area of haemolysis formed by β-haemolysin from S. aureus.
p.42
Identification of Gram Positive Organisms
Describe the colony appearance of Streptococcus agalactiae.
Large, translucent to opaque, flat, grey-white colony.
p.14
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What technology does VITEK MS utilize?
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) mass spectrometry.
p.32
Identification of Gram Positive Organisms
What are the catalase and oxidase results for Micrococcus?
Catalase positive, oxidase positive.
p.52
Methicillin-Resistant Staphylococcus aureus (MRSA)
What is the resistance level associated with the van B gene?
Intermediately to highly resistant to vancomycin (e.g., 16 – 256 μg/mL) but sensitive to teicoplanin, and is plasmid-borne.
p.47
Identification of Gram Positive Organisms
What is the shape and arrangement of Enterococcus bacteria?
Gram-positive cocci in chains, resembling Streptococcus.
p.18
Identification of Gram Positive Organisms
What type of bacteria is Staphylococcus?
Gram positive cocci in clusters.
p.4
Bacterial Cell Shape and Arrangement
What are cocci?
Spherical-shaped bacteria.
p.1
Identification of Gram Positive Organisms
What type of organisms are discussed in Lecture 3 Topic 2?
Aerobic Gram Positive Organisms.
p.24
Methicillin-Resistant Staphylococcus aureus (MRSA)
What type of infection is associated with MRSA?
Hospital-acquired/associated infection (HAI).
p.51
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What is the current status of VRE cases in Hong Kong?
The VRE case in Hong Kong is under control.
p.16
Identification of Gram Positive Organisms
What are some specific tests used to identify species of Gram positive cocci?
Coagulase, optochin, bacitracin, PYR, and/or Lancefield test.
p.23
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
How does S. aureus develop drug resistance?
Through genetic mutations and horizontal gene transfer.
p.2
Bacterial Cell Arrangement
What is the arrangement of bacilli bacteria?
They can be found singly, in pairs, or in chains.
p.52
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What is the primary resistance mechanism discussed?
Alteration of peptidoglycan synthesis pathway.
p.63
Clinical Significance of Staphylococcus Species
Where is Lactobacillus commonly found in the human body?
In the oral cavity, gastrointestinal tract, and female genital tract.
p.25
Methicillin-Resistant Staphylococcus aureus (MRSA)
What gene does SCC mec contain?
The mecA gene and other genes.
p.8
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
Why does each bacterial species produce a different mass spectrum?
Because each species has a different protein composition.
p.33
Streptococcus Identification and Clinical Relevance
What is the shape and arrangement of Streptococcus bacteria?
Gram-positive cocci in chains; S. pneumoniae appears in diplococci.
p.8
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
How is the mass spectrum used in bacterial identification?
It is compared to reference strains in a database for closely matched bacterial identity.
p.49
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What does VRE stand for?
Vancomycin-resistant Enterococcus.
p.66
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What type of oxygen conditions do Actinomyces prefer for optimal growth?
Microaerophilic or anaerobic conditions.
p.52
Methicillin-Resistant Staphylococcus aureus (MRSA)
What is the resistance level associated with the van M gene?
High-level resistance to vancomycin and usually teicoplanin (e.g., >256 μg/mL), and is chromosome-borne.
p.64
Identification of Gram Positive Organisms
What type of bacteria is Listeria?
Gram positive short rods.
p.49
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What led to the increase in VRE prevalence in healthcare settings?
Increased consumption of vancomycin.
p.32
Clinical Significance of Staphylococcus Species
Where are Micrococcus usually found?
As contaminants from skin, mucosa, oropharynx, or environments.
p.58
Gram Positive Rods/Bacilli and Their Clinical Importance
What are the two main categories of Gram positive rods?
Spore forming and Non-spore forming.
p.26
Methicillin-Resistant Staphylococcus aureus (MRSA)
What are the risk factors for CA-MRSA?
Affecting younger and healthy individuals.
p.9
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What is the primary application of MALDI-TOF?
Mass spectrometry for identifying biomolecules.
p.41
Clinical Significance of Staphylococcus Species
What complications can arise if Streptococcus infections are left untreated?
Rheumatic heart disease or acute glomerulonephritis.
p.51
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
In which departments have VRE outbreaks occurred in Hong Kong?
Renal, medicine, and orthopaedics departments.
p.16
Identification of Gram Positive Organisms
What is the first step in detecting potential pathogens among Gram positive cocci?
Screening tests to group into genera, such as catalase and oxidase tests.
p.27
Identification of Gram Positive Organisms
What is a common method used for bacterial culture in laboratory diagnosis?
Broth based enrichment with NaCl salt.
p.10
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What is the main focus of the article by Clark et al.?
Matrix-Assisted Laser Desorption Ionization – Time of Flight Mass Spectrometry in clinical microbiology.
p.50
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
Why is VRE a concern in healthcare settings?
It is resistant to vancomycin, making infections difficult to treat.
p.38
Streptococcus Identification and Clinical Relevance
What is the basis for Lancefield grouping?
Carbohydrate antigens on the cell wall.
p.52
Methicillin-Resistant Staphylococcus aureus (MRSA)
What does the van A gene confer?
High-level resistance to both vancomycin and teicoplanin (e.g., >256 μg/mL), and is plasmid-borne.
p.65
Gram Positive Rods/Bacilli and Their Clinical Importance
What type of hemolysis do Erysipelothrix bacteria exhibit?
α-haemolytic small colony.
p.54
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
Why is antibiotic resistance a concern with VRE?
Limited treatment options and potential transfer of resistance to other organisms.
p.26
Methicillin-Resistant Staphylococcus aureus (MRSA)
What does CA-MRSA stand for?
Community-associated Methicillin-Resistant Staphylococcus aureus.
p.65
Gram Positive Rods/Bacilli and Their Clinical Importance
What indicates hydrogen sulfide production in Erysipelothrix?
Formation of black precipitate on triple sugar iron (TSI) agar.
p.25
Methicillin-Resistant Staphylococcus aureus (MRSA)
What is the result of mecA gene expression?
Loss of target affinity due to the production of a new PBP2a.
p.31
Clinical Significance of Staphylococcus Species
What common infection does Staphylococcus saprophyticus cause?
Urinary tract infection in young women.
p.48
Clinical Significance of Staphylococcus Species
What type of infections are Enterococcus species associated with in healthcare settings?
Nosocomial urinary tract infections.
p.59
Identification of Gram Positive Organisms
How can clinical specimen isolates of Bacillus appear under Gram staining?
They can be Gram variable or appear Gram-negative.
p.26
Methicillin-Resistant Staphylococcus aureus (MRSA)
What gene do CA-MRSA strains carry?
PVL gene (Panton-Valentine leucocidin).
p.47
Identification of Gram Positive Organisms
What biochemical tests are Enterococcus positive for?
PYR, bile esculin, and 6.5% NaCl.
p.12
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What are the three components that make up the Bruker MALDI-TOF score?
1. Number of matching peaks in the reference spectrum. 2. Number of matching peaks in the test spectrum. 3. Peak height symmetry of matching peaks.
p.23
Methicillin-Resistant Staphylococcus aureus (MRSA)
What is S. aureus?
Staphylococcus aureus, a type of bacteria.
p.53
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
Who is considered a susceptible host for VRE?
Severely ill patients, those receiving multiple and prolonged courses of antimicrobial therapy, and organ transplant recipients.
p.27
Identification of Gram Positive Organisms
What type of agar is commonly used in bacterial culture?
Chromogenic culture agar, such as bioMérieux and BBL.
p.63
Identification of Gram Positive Organisms
What type of colony does Lactobacillus form?
Aerobic, tiny, α-hemolytic grey colony.
p.23
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What factors contribute to the development of drug resistance in S. aureus?
Overuse and misuse of antibiotics, as well as poor infection control practices.
p.30
Identification of Gram Positive Organisms
What biochemical tests is Staphylococcus lugdunensis positive for?
Ornithine decarboxylase and PYR.
p.63
Clinical Significance of Staphylococcus Species
What is Lactobacillus classified as?
A probiotic, or good bacteria.
p.26
Methicillin-Resistant Staphylococcus aureus (MRSA)
What distinguishes CA-MRSA from HA-MRSA?
CA-MRSA strains are isolated from individuals in the community without recent healthcare exposure.
p.6
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
How are sample molecules ionized in MALDI-TOF?
Sample molecules are ionized and transferred into a gas phase, generating charged ions.
p.64
Identification of Gram Positive Organisms
How does the colony and Gram stain morphology of Listeria compare to S. agalactiae?
It may resemble S. agalactiae (GBS).
p.33
Streptococcus Identification and Clinical Relevance
How are haemolytic reactions best observed?
With transmitted light shining from behind the agar plate.
p.18
Clinical Significance of Staphylococcus Species
Which Staphylococcus species is associated with animal flora and can cause human disease?
Staphylococcus intermedius.
p.58
Gram Positive Rods/Bacilli and Their Clinical Importance
Which Gram positive rods are non-acid-fast?
Corynebacterium, Lactobacillus, Listeria, Erysipelothrix.
p.34
Streptococcus Identification and Clinical Relevance
What is the significance of Lancefield classification?
It categorizes Streptococcus based on carbohydrate composition of antigens.
p.26
Methicillin-Resistant Staphylococcus aureus (MRSA)
What are common risk factors for HA-MRSA?
Long-term hospitalization, surgery, and ICU stays.
p.62
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
Do Corynebacterium species form spores?
No, they do not form spores.
p.13
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What additional information does the Biotyper provide?
Matching hints with further taxonomical information or cautionary details.
p.47
Identification of Gram Positive Organisms
What type of hemolysis is Enterococcus usually associated with?
α or γ-hemolytic, with rare β-hemolytic.
p.19
Coagulase-Positive and Coagulase-Negative Staphylococci
What are the two forms of coagulase?
Bound coagulase and free coagulase.
p.6
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What accelerates the ions in MALDI-TOF?
An applied electrical field of known strength.
p.59
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
Are spores always visible in direct smears of Bacillus?
No, spores may not be visible in direct smears but appear in colony smears.
p.6
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What is detected and measured in MALDI-TOF?
Ions are detected and measured using the time-of-flight mass spectrometer.
p.48
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
Are most Enterococcus species vancomycin sensitive or resistant?
Most are vancomycin sensitive, but vancomycin-resistant Enterococcus (VRE) emerges.
p.28
Methicillin-Resistant Staphylococcus aureus (MRSA)
What happens if a patient tests positive for MRSA?
The patient will be isolated in a single room and health care workers will follow strict contact precautions.
p.31
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What is a specific note about the Bruker MALDI-TOF for Staphylococcus saprophyticus?
It may show no matching hint.
p.35
Streptococcus Identification and Clinical Relevance
What should be done to confirm the identification of Streptococcus pneumoniae?
Further tests like bile test or optochin test.
p.60
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What characterizes cutaneous anthrax?
Wound infection and 'malignant pustule', seldom fatal.
p.61
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What is notable about the toxin produced by Bacillus cereus?
It is resistant to heat and not easily destroyed by cooking.
p.7
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What does MALDI-TOF stand for?
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight.
p.31
Identification of Gram Positive Organisms
What is the coagulase test result for Staphylococcus saprophyticus?
Positive for bound coagulase, but negative for free coagulase.
p.66
Clinical Significance of Staphylococcus Species
What condition is associated with Actinomyces infections?
Actinomycosis, which causes abscesses of the jaw and sinus tracts to the skin surface.
p.61
Clinical Significance of Staphylococcus Species
What infections is Bacillus cereus associated with?
Gastrointestinal infections, local infections, and systemic infections.
p.7
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What happens to ions after they are accelerated in MALDI-TOF?
They travel over a drift path to the detector.
p.21
Clinical Significance of Staphylococcus Species
What are the symptoms of cellulitis caused by Staphylococcus aureus?
Redness, heat, swelling, and pain in the dermis.
p.20
Identification of Gram Positive Organisms
What are the results of the coagulase test for Staphylococcus aureus?
Slide and tube coagulase: positive.
p.21
Clinical Significance of Staphylococcus Species
What enzymes does Staphylococcus aureus produce in soft-tissue infections?
Hyaluronidase and lipase.
p.45
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What is the challenge in distinguishing between species canis and dysgalactiae?
They have very similar patterns in MALDI-TOF.
p.60
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
Can Bacillus anthracis be identified by MALDI-TOF?
No, it cannot be identified by MALDI-TOF.
p.29
Coagulase-Positive and Coagulase-Negative Staphylococci
In which type of patients does Coagulase-negative Staphylococcus cause problems?
Immunocompromised patients.
p.62
Clinical Significance of Staphylococcus Species
Where is Corynebacterium commonly found?
As human skin flora and widely distributed in nature.
p.32
Clinical Significance of Staphylococcus Species
In which patients may Micrococcus act as an opportunistic pathogen?
In immunocompromised patients.
p.7
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What role does the electric field play in MALDI-TOF?
It accelerates ions, giving them the same kinetic energy if they have the same charge.
p.48
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What does Bruker MALDI-TOF indicate when there is no matching hint?
It suggests a lack of identification for the organism.
p.29
Coagulase-Positive and Coagulase-Negative Staphylococci
Why are artificial devices at risk when infected by Coagulase-negative Staphylococcus?
Due to poor blood circulation.
p.28
Methicillin-Resistant Staphylococcus aureus (MRSA)
What was the effect of implementing MRSA PCR screening on ICU-acquired MRSA infections?
The infections decreased compared to culture periods.
p.60
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What are the three forms of anthrax?
Gastrointestinal, cutaneous, and inhalational anthrax.
p.60
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What are the symptoms of gastrointestinal anthrax?
Mild diarrhea, fever, and chills.
p.49
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What was the prevalence of VRE in enterococcal isolates from hospitalized patients in Europe from 1990 to 1997?
Increased from less than 1% to approximately 15%.
p.21
Clinical Significance of Staphylococcus Species
Where can Staphylococcus aureus be found besides humans?
In farm and domesticated animals.
p.66
Clinical Significance of Staphylococcus Species
Is Actinomyces considered normal flora?
Yes, it is commensal or normal flora in various body sites, especially the mouth.
p.20
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What can occur with prolonged antibiotic therapy in patients with persistent infections?
Small variant colonies (SVC) of Staphylococcus aureus.
p.19
Coagulase-Positive and Coagulase-Negative Staphylococci
What is the nature of free coagulase?
It is secreted into the extracellular environment.
p.64
Clinical Significance of Staphylococcus Species
What disease does Listeria monocytogenes cause in vulnerable populations?
Meningitis in neonates, pregnant women, and immunocompromised patients.
p.46
Clinical Significance of Staphylococcus Species
What infections can Streptococcus gallolyticus cause?
Bacteraemia and endocarditis.
p.20
Identification of Gram Positive Organisms
What is the appearance of Staphylococcus aureus colonies on blood agar?
White to golden yellow convex colonies.
p.6
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
On what basis are ions separated in MALDI-TOF?
On the basis of their mass-to-charge ratio (m/z).
p.11
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What are the authors discussing in relation to MALDI-TOF mass spectrometry?
Current issues in clinical microbiology.
p.45
Clinical Significance of Staphylococcus Species
What infections can Streptococcus dysgalactiae subsp equisimilis cause?
Pharyngitis, skin and soft tissue infections, toxic shock-like syndrome, bacteraemia, arthritis, osteomyelitis, respiratory infections, abscesses, endocarditis, and meningitis.
p.7
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
How does the mass-to-charge ratio affect the velocity of ions in MALDI-TOF?
Heavier ions of the same charge reach lower speeds, while ions with higher charge increase in velocity.
p.60
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
Is Bacillus anthracis sensitive to penicillin?
Yes, it is sensitive to penicillin.
p.33
Streptococcus Identification and Clinical Relevance
On which types of agar do Streptococcus bacteria grow best?
Blood Agar (BA) and Chocolate agar.
p.35
Streptococcus Identification and Clinical Relevance
What conditions enhance the growth of Streptococcus pneumoniae?
Better growth in CO2 or anaerobic conditions.
p.65
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
How does Erysipelothrix respond to vancomycin?
It is resistant to vancomycin.
p.31
Identification of Gram Positive Organisms
What biochemical tests confirm Staphylococcus saprophyticus?
Positive for urease and sucrose fermentation; negative for nitrate reductase and xylose fermentation.
p.33
Streptococcus Identification and Clinical Relevance
What characterizes alpha-prime hemolysis (α′)?
A small zone of intact erythrocytes adjacent to the bacterial colony, surrounded by a zone of complete red-cell hemolysis.
p.7
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
Why do lighter ions arrive at the detector before heavier ones in MALDI-TOF?
Because they travel faster due to their lower mass-to-charge ratio.
p.59
Bacterial Cell Shape and Arrangement
What is the typical appearance of Bacillus colonies?
Usually large, whitish-greyish, spreading colonies with irregular edges.
p.28
Methicillin-Resistant Staphylococcus aureus (MRSA)
What is the primary goal of MRSA screening in the ICU?
To prevent the spread of MRSA.
p.21
Clinical Significance of Staphylococcus Species
What are two serious conditions caused by Staphylococcus aureus?
Food poisoning and Toxic Shock Syndrome.
p.21
Clinical Significance of Staphylococcus Species
How can Staphylococcus aureus be isolated from clinical specimens?
As a colonizer or a pathogen.
p.19
Coagulase-Positive and Coagulase-Negative Staphylococci
How is bound coagulase detected?
By slide test or commercial test like Staphaurex.
p.59
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What type of anaerobes are most Bacillus species?
Most are facultative anaerobes, some are obligate aerobes.
p.49
Enterococcus and Vancomycin-Resistant Enterococcus (VRE)
What was banned in the livestock industry by the European Union in 1997?
The widespread use of avoparcin.
p.45
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
How does the virulence of Streptococcus dysgalactiae subsp equisimilis compare to S. pyogenes?
It is relatively less virulent than S. pyogenes.
p.46
Clinical Significance of Staphylococcus Species
What is the significance of Streptococcus gallolyticus in the gastrointestinal system?
It is part of the normal flora.
p.37
Clinical Significance of Staphylococcus Species
What is the clinical significance of Viridans Streptococcus?
Associated with endocarditis, bacteraemia, and meningitis.
p.61
Clinical Significance of Staphylococcus Species
What is a common practice that leads to Bacillus cereus outbreaks?
Storing boiled rice at room temperature.
p.31
Identification of Gram Positive Organisms
How is Staphylococcus saprophyticus screened?
By novobiocin disk; it is resistant to novobiocin.
p.46
Streptococcus Identification and Clinical Relevance
What are the colony characteristics of Streptococcus gallolyticus?
Small grey or domed colonies.
p.45
Identification of Gram Positive Organisms
What is the PYR test result for Streptococcus dysgalactiae subsp equisimilis?
Positive for Group A, but PYR negative.
p.37
Clinical Significance of Staphylococcus Species
What dental conditions are Viridans Streptococcus responsible for?
Gingivitis and dental caries.
p.60
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What happens to highly pathogenic microorganisms like Bacillus anthracis in the MBT IVD Library?
They cannot be identified or will be commented within the Matching Hints of closely related less pathogenic microorganisms.
p.29
Coagulase-Positive and Coagulase-Negative Staphylococci
What condition can Coagulase-negative Staphylococcus cause related to prosthetic devices?
Prosthetic valve endocarditis.
p.21
Clinical Significance of Staphylococcus Species
What type of infections can Staphylococcus aureus cause?
Skin infections and skin lesions.
p.31
Identification of Gram Positive Organisms
What commercial identification cards can be used for Staphylococcus saprophyticus?
Vitek 2 GPI and API Staph.
p.60
Identification of Gram Positive Organisms
What type of colony does Bacillus anthracis form?
Non-haemolytic colony with irregular borders.
p.64
Clinical Significance of Staphylococcus Species
In which types of food is Listeria commonly found?
Dairy products, e.g., cheese and ice cream.
p.61
Clinical Significance of Staphylococcus Species
What happens to rice that is cooked and left to cool at room temperature?
Bacillus cereus can contaminate and grow on it.
p.33
Streptococcus Identification and Clinical Relevance
What are the types of hemolysis associated with Streptococcus?
Alpha (α), beta (β), alpha-prime (α′), and gamma (γ) hemolysis.
p.7
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What is recorded to determine the mass spectrum in MALDI-TOF?
The flight time of each ion.
p.31
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What advanced method can be used for identifying Staphylococcus saprophyticus?
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF).
p.61
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
Which method is used to differentiate Bacillus cereus from Bacillus anthracis?
Bruker MALDI-TOF mass spectrometry.
p.46
Identification of Gram Positive Organisms
What is a challenge in distinguishing species within the genus Streptococcus?
Species equinus, gallolyticus, infantarius, and lutetiensis have very similar patterns.
p.61
Clinical Significance of Staphylococcus Species
Can reheating fried rice eliminate the risk of fried rice syndrome?
No, the toxin can still cause illness even if reheated.
p.35
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
Which MALDI-TOF method can identify Streptococcus pneumoniae?
Bruker MALDI-TOF and Biomerieux MALDI-TOF.
p.64
Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry
What is required for reliable species identification of Listeria using Bruker MALDI-TOF?
Extraction must be performed.
p.60
Pathogenesis and Resistance Mechanisms of Gram Positive Bacteria
What is a key feature of inhalational anthrax?
Inhalation of spores may result in respiratory distress and death.
