Module 11 HW, Lecture, Lab qs

____ hemolysis is the full and complete lysis of red blood cells due to _______ A.Alpha, catalase B.Beta, hemolysins C.Gamma, hyaluronidase D.Alpha, hemolysins E.Beta, coagulase

B.Beta, hemolysins Beta hemolysis is a type of hemolysis characterized by the complete lysis or destruction of red blood cells. This hemolytic activity is typically caused by the secretion of alpha hemolysins by certain bacteria. Alpha hemolysins are a type of cytolytic toxin that can disrupt the integrity of red blood cells, leading to their rupture and release of hemoglobin. The presence of beta hemolysis on a blood agar plate is often indicated by a clear or transparent zone around the bacterial colonies, indicating the complete destruction of red blood cells. This phenomenon is commonly associated with certain pathogenic bacteria, such as Streptococcus pyogenes or Staphylococcus aureus, and can aid in the identification and classification of these organisms in laboratory diagnostics.

What is the most widely respected resource for bacterial identification?

Bergey's Manual of Determinative Bacteriology

A 55-year-old male patient presented to the hospital with a sudden onset of symptoms including high fever, productive cough with rusty-colored sputum, chest pain, and shortness of breath. The patient reported feeling fatigued and weak for the past few days. Upon physical examination, the patient displayed signs of respiratory distress with decreased breath sounds and dullness upon percussion over the affected lung area. Laboratory tests revealed numerous lancet-shaped gram-positive cocci in pairs. The culture was alpha-hemolytic and optochin-sensitive. Which of the following organisms is causing the patient's symptoms? A.S. pyogenes B.S. agalactiae C.S. pneumoniae D.S. aureus

C.S. pneumoniae Based on the symptoms, physical examination findings, and laboratory results, the organism causing the patient's symptoms is most likely Streptococcus pneumoniae. The presence of numerous lancet-shaped gram-positive cocci in pairs is characteristic of S. pneumoniae. The culture exhibiting alpha-hemolysis and being optochin-sensitive are additional diagnostic features of S. pneumoniae. This bacterium is a common cause of pneumonia, and the patient's symptoms, including high fever, productive cough with rusty-colored sputum, chest pain, and shortness of breath, are consistent with pneumococcal pneumonia.

Which organism is most likely to be acquired from a contaminated door handle? A.Escherichia coli B.Streptococcus pyogenes C.Staphylococcus aureus D.Streptococcus pneumonia

C.Staphylococcus aureus Staphylococcus aureus is the most likely organism to be acquired from a contaminated door handle. This bacterium is commonly found on human skin and can survive on surfaces, making it easily transferable through contact. Staphylococcus aureus can cause a range of infections, from minor skin infections like boils and impetigo to more severe conditions such as pneumonia and bloodstream infections. It is important to practice good hand hygiene and regularly clean frequently touched surfaces to minimize the risk of acquiring this bacterium and prevent its spread.

What test is used to distinguish between staphylococci and streptococci?

Catalase test The catalase test is commonly used to distinguish between staphylococci and streptococci. The catalase enzyme catalyzes the breakdown of hydrogen peroxide into water and oxygen. Staphylococci are catalase-positive, meaning they produce the catalase enzyme and will bubble when hydrogen peroxide is added. -On the other hand, streptococci are catalase-negative, so they do not produce the catalase enzyme, and no bubbles will be observed in the presence of hydrogen peroxide.

Which of the following effects are caused by the formation of an infectious biofilm? A.Disseminated infection B.failure of drug therapy C.colonization of tissue D.all of these

D.all of these All of these effects can be caused by the formation of an infectious biofilm. When bacteria form a biofilm, they create a protective matrix that allows them to adhere to surfaces and resist immune responses and antibiotic treatments. This can lead to a variety of consequences, including disseminated infection (where the infection spreads to other parts of the body), failure of drug therapy (as biofilm-embedded bacteria are often more resistant to antibiotics), and colonization of tissue (where the biofilm can establish itself and cause persistent infection). The formation of biofilms poses significant challenges in the management and treatment of infectious diseases.

Why is it important to consider a detailed cardiovascular and infection history in dental patients?

Dental procedures can introduce bacteria into the bloodstream, posing a risk of infective endocarditis for patients with cardiovascular issues. Understanding infection history helps assess the risk and tailor preventive measures.

Using laboratory testing, distinguish between staphylococcus & streptococcus?

Laboratory testing typically involves Gram staining and catalase testing. Staphylococci are Gram-positive cocci that are catalase-positive, while streptococci are also Gram-positive cocci but are catalase-negative.

A gram-positive coccus that is catalase positive and coagulase positive is identified as ________.

Staphylococcus aureus

A microorganism that grows on mannitol salt agar and causes the medium to turn yellow in color is most likely ______________________.

Staphylococcus aureus

Explain the relevance of virulence factors in disease. Pick one organism and give three examples?

Virulence factors enhance the ability of microorganisms to cause disease. For Staphylococcus aureus, examples include coagulase (promotes clot formation), hemolysins (damage host cells), and exotoxins (cause toxic effects).

Based on the carbohydrate antigens in its cell wall, Streptococcus pyogenes is classified within which Lancefield group? a. A (the group A strep) b. B (the group B strep) c. C (the group C strep) d. D (the group D strep)

a. A (the group A strep) Streptococcus pyogenes has specific carbohydrate antigens in its cell wall that belong to the Lancefield group A. These carbohydrate antigens are distinct from those found in other Lancefield groups (B, C, and D). The Lancefield classification system allows healthcare professionals to differentiate various Streptococcus species based on their unique cell wall antigens. This classification helps understand the epidemiology, pathogenicity, and treatment options for infections caused by different Streptococcus species. Streptococcus pyogenes, which belongs to group A, is responsible for various human infections, including strep throat, impetigo, cellulitis, and more severe invasive diseases such as necrotizing fasciitis and toxic shock syndrome.

Once you have a pure culture of the bacteria to be identified, what is the first step in the identification process? a. determine what fermentation pathway is used by the bacteria b. determine whether the bacteria ferment glucose c. determine the Gram stain morphology

c. determine the Gram stain morphology The first most important step in bacterial identification (once you have a pure culture of the bacteria) is to determine the Gram stain morphology. The is the beginning step on most bacterial identification flowcharts.

The identification approach represented by the charts and tables that can be found in Bergey's Manual of Determinative Bacteriology are based on a. DNA microarray information. b. 16s RNA sequences. c. morphological and physiological characteristics

c. morphological and physiological characteristics Bergey's Manual of Determinative Bacteriology uses the phenotypic approach to bacterial identification, including both microscopic and macroscopic morphological features as well as numerous biochemical features.

question 14 on lab 10

fill in

Case Study: Maria, a 28-year-old parent of three rambunctious young children, presented to her doctor's office complaining of frequent urination, a burning sensation during urination, lower abdominal pain, and a low-grade fever. These symptoms started a couple of days ago and have progressively worsened. Her doctor suspected a urinary tract infection (UTI) and requested a urine sample for analysis. The urinalysis showed a high number of white blood cells and the presence of bacteria. Further laboratory tests identified a Gram-negative, rod-shaped bacterium that is motile and ferments lactose robustly but does not utilize citrate. Question: Given the laboratory findings and Maria's symptoms, it is likely her infection is caused by which of the following pathogens? a. Escherichia coli b. Staphylococcus aureus c. Neisseria gonorrhoeae d. Pseudomonas aeruginosa

a. Escherichia coli The characteristics provided in the scenario are all indicative of Escherichia coli, a common cause of urinary tract infections (UTIs). Gram-negative bacteria are known to cause UTIs, and E. coli is the most common gram-negative bacterium that causes UTIs. E. coli is also motile and has strong lactose fermenting, which helps to differentiate it from other possible bacteria, such as Pseudomonas aeruginosa, which is not a lactose fermenter. In addition, E. coli cannot utilize citrate, which is also a characteristic that helps to narrow down the possible bacterial species causing the UTI. Staphylococcus aureus is a gram-positive bacterium that is not motile and does not ferment lactose. Neisseria gonorrhoeae is a gram-negative diplococcus bacterium and is not a common cause of UTIs. Therefore, based on the given characteristics, the most likely causative agent for the UTI is Escherichia coli.

dentify items in this list that are characteristic of all members of the genus Staphylococcus. Check All That Apply a. Gram-positive cocci b. Cells are arranged in irregular clusters c. Cells are arranged in pairs and chains d. Catalase-positive e. Beta-hemolytic on blood agar f. Able to grow in 6.5% NaCl g. Able to grow in the presence of bile

a. Gram-positive cocci b. Cells are arranged in irregular clusters d. Catalase-positive f. Able to grow in 6.5% NaCl

Identify items in this list that are characteristic of the genus Streptococcus. Check All That Apply a. Gram-positive cocci b. Cells are arranged in pairs and chains c. Cells are arranged in irregular clusters d. Catalase negative e. Coagulase positive f. The type of hemolysis on blood agar is a helpful identifying feature.

a. Gram-positive cocci b. Cells are arranged in pairs and chains d. Catalase negative f. The type of hemolysis on blood agar is a helpful identifying feature.

Case Study: John has been suffering from chronic stomach pain for the past six months. He has also been experiencing nausea, frequent heartburn, and unintended weight loss. Initially, John attributed these symptoms to stress and ignored them. However, his discomfort continued to worsen over time. His primary care doctor referred him to a gastroenterologist for further investigation. The gastroenterologist recommended an endoscopy to understand the cause of John's symptoms better. The endoscopy results revealed inflammation in John's stomach lining and a small ulcer. The gastroenterologist also took a biopsy during the endoscopy for bacterial culture. Based on John's symptoms and the endoscopy findings, what is the scientific name of the unusual bacterium that the doctor might suspect, which is known to survive in the stomach's acidic environment and is associated with peptic ulcers and an increased risk of stomach ca

a. Heliobacter pylori Helicobacter pylori is a spiral-shaped, gram-negative bacterium that can survive in the stomach's acidic environment. It has several mechanisms that allow it to withstand the low pH levels of the stomach, including the production of urease, an enzyme that converts urea to ammonia and bicarbonate, which neutralizes the acid around the bacterium. Helicobacter pylori colonize the gastric mucosa and can cause chronic inflammation, leading to peptic ulcers in the stomach or duodenum. The bacterium can also produce toxins that damage the epithelial cells of the stomach lining and interfere with the production of mucus and bicarbonate, which normally protect the stomach lining from acid damage. The combination of these factors can lead to the development of peptic ulcers, which can cause symptoms such as abdominal pain, bloating, nausea, and vomiting.

Which of the following are key tests used to differentiate Streptococcus species? Check All That Apply a. Observation of hemolysis on blood agar b. Bacitracin susceptibility c. Coagulase test d. Bile esculin hydrolysis e. Optochin susceptibility

a. Observation of hemolysis on blood agar b. Bacitracin susceptibility d. Bile esculin hydrolysis e. Optochin susceptibility Hemolytic activity is a key differentiating feature for the streptococci.Bacitracin sensitivity is used to identify Streptococcus pyogenes from other beta-hemolytic streptococci.Esculin hydrolysis differentiates the enterococci from the streptococci.Streptococcus pneumoniae is differentiated by its sensitivity to optochin

Which of these organisms would most likely be acquired from a contaminated doorknob? a. Staphylococcus aureus b. Streptococcus pyogenes c. Neisseria meningitidis d. Streptococcus pneumoniae e. All of these

a. Staphylococcus aureus Staphylococcus aureus would most likely be acquired from a contaminated doorknob. Staphylococcus aureus is a common bacterium that can live on various surfaces, including the skin and inanimate objects, for extended periods. It is known for its ability to survive on environmental surfaces, making it a common cause of skin and soft tissue infections, especially after direct contact with contaminated surfaces. The other listed organisms are typically spread through other means, and they are not as commonly associated with contamination of inanimate objects like doorknobs.

Case Study: Jason, a 36-year-old construction worker, was involved in a serious work-site accident. A large piece of debris fell and crushed his right leg, resulting in a deep, contaminated wound. Jason was rushed to the hospital, where he underwent emergency surgery to clean and repair the injury. Despite the initial treatment, Jason started experiencing severe pain in his leg 48 hours post-surgery, accompanied by swelling, pallor, and dark blisters. His wound also started producing a foul-smelling gas, and his vitals showed a rapid heart rate and low blood pressure. The medical team suspected an aggressive infection and immediately started him on broad-spectrum antibiotics while sending wound cultures to the lab to identify the specific pathogen. Based on Jason's symptoms and the progression of his condition, which pathogen is most likely responsible for causing what is known as gas gangrene? a. Streptococcus spp.

b. Clostridium spp. Gas gangrene is caused by the pathogen Clostridium spp., particularly Clostridium perfringens. This anaerobic, spore-forming bacterium produces gas and toxins in the infected tissue, leading to rapid tissue destruction, swelling, and a characteristic foul smell. The gas production is a result of the bacterium's metabolism, and the toxins released contribute to the rapid progression of the disease, tissue damage, and potentially life-threatening systemic effects

A small town relies on a local well as its main source of drinking water. Recently, there have been reports of gastrointestinal illnesses among residents, indicating potential waterborne contamination. To ensure the safety of the drinking water supply, the local health department conducts fecal coliform testing. As part of this testing, they perform a (Coli-blue) filter assay to capture potential contaminants. And performed gram stain and grew contaminants from the filter plate onto MacConkey. The results are below (1) blue colonies on Coli-blue plate, (2) pink gram-stained colonies, and (3) hot pink colonies on MacConkey. The likely culprit is a. Salmonella b. Escherichia coli c. Pseudomonas aeruginosa d. Giardia intestinalis

b. Escherichia coli -The fact that the colonies are pink suggests that they are Gram-negative bacteria -MacConkey agar is a selective and differential medium that distinguishes between lactose fermenters (which produce pink colonies) and non-lactose fermenters. The hot pink color on MacConkey agar suggests that the bacteria are lactose fermenters.

Which of the following is an obligate parasite? a. Clostridioides difficile b. Mycobacterium leprae c. Corynebacterium diphtheriae d. Mycobacterium tuberculosis

b. Mycobacterium leprae Mycobacterium leprae is an obligate parasite. It is the causative agent of leprosy and cannot be grown on artificial laboratory media. Its obligate parasitic nature means it requires a host (either human or armadillo) to grow, reproduce, and complete its life cycle. The other listed organisms can be cultured on artificial media outside of a host.

What step should occur prior to starting the identification process? a. determination of antibiotic susceptibility b. isolation of the bacteria to be identified in pure culture c. determination of presence of capsules

b. isolation of the bacteria to be identified in pure culture The organism to be identified must be in pure culture prior to starting any of the identification steps. Before starting the identification process, it is crucial to isolate the bacteria in a pure culture. This means separating the target bacteria from other microorganisms and obtaining a sample that contains only the specific type of bacteria being studied. This isolation step is essential for accurate identification because it allows researchers to focus on the characteristics of the specific bacterium without interference from other organisms. Once the bacteria are isolated, various identification methods, such as biochemical tests or molecular techniques, can be applied to determine the bacterial species

TB, tuberculosis, is spread by a. contaminated food b. respiratory droplets c. contaminated fomites d. zoonotic vectors

b. respiratory droplets Respiratory droplets are the primary means of spreading TB (tuberculosis). When an individual with active pulmonary TB coughs, sneezes, speaks, or sings, they can release droplets containing Mycobacterium tuberculosis into the air, which can then be inhaled by others, potentially leading to infection

A 45-year-old patient presents to the clinic with complaints of fever, sore throat, and difficulty swallowing. On physical examination, the patient has an elevated temperature, tonsillar exudates, and enlarged cervical lymph nodes. A rapid antigen test confirms the presence of GAS. Additional test results are below - purple gram-stained cells and results of a bacitracin sensitivity test. Which of the following organisms is likely causing the patient's symptoms? a. S. agalactiae b. S. pneumoniae c. S. pyogenes d. S. aureus

c. S. pyogenes The presence of tonsillar exudates, enlarged cervical lymph nodes, and a positive rapid antigen test indicate streptococcal pharyngitis. The additional test results of gram-positive cocci in chains, beta-hemolysis, and bacitracin sensitivity are also consistent with GAS. Staphylococcus aureus is a gram-positive coccus that can cause various infections, including skin and soft tissue infections, pneumonia, and sepsis. However, it does not exhibit beta-hemolysis and is not sensitive to bacitracin. Streptococcus pneumoniae is another gram-positive coccus that can cause respiratory infections such as pneumonia and sinusitis, but it does not exhibit beta-hemolysis and is not sensitive to bacitracin. Streptococcus agalactiae is a gram-positive coccus that can cause infections such as neonatal sepsis, meningitis, and pneumonia, but it exhibits a different type of hemolysis (group B) and is not sensitive to bacitracin.

The catalase test can be used to distinguish a. Enterococci from other Streptococci b. S. aureus from other Staphylococci c. Staphylococci from Streptococci d. S. pyogenes from other Streptococci

c. Staphylococci from Streptococci The catalase test is used to differentiate between Staphylococci and Streptococci based on their ability to produce the enzyme catalase. Staphylococci are catalase-positive, meaning they produce catalase, while Streptococci are catalase-negative and do not produce the enzyme.

All of the following are examples of morphological features which can assist in bacterial identification except a. Gram stain reaction. b. cell shape and arrangement. c. ability to ferment lactose. d. presence of endospores.

c. ability to ferment lactose Morphological features include microscopic and staining features such as Gram stain reaction, cell shape and arrangements, presence of endospores, capsules, and flagella, as well as macroscopic features, such as appearance of colonies on different types of media.

Case Study: Marcus, a 75-year-old retiree with a history of diabetes who recently underwent hip replacement surgery, returned to the hospital with signs of infection around his prosthetic joint. Despite being discharged in a healthy condition a few weeks earlier, Marcus began to experience increasing pain, swelling, and redness around the surgical site. Lab tests revealed an elevated white blood cell count, suggesting an active infection. During the follow-up surgery, the medical team noticed a slimy, film-like substance on the surface of the hip prosthesis. The team took samples for further microbial analysis. The lab results confirmed the presence of a biofilm composed not only of bacteria but also of other microorganisms and viruses. It appeared that the biofilm was significantly hampering the effectiveness of the antibiotics prescribed to Marcus. Question: Which of the following is true about biofilms like the on

d. Biofilms often form on medical devices, like prosthetic joints and catheters, and cells within biofilms are generally more resistant to antibiotics. Biofilms are complex, three-dimensional communities of microorganisms that adhere to surfaces and produce an extracellular matrix. This matrix helps attach cells to a surface and protects the microorganisms within the biofilm. The following statements about biofilms are true - Biofilms often form in wounds and are associated with medical devices such as prosthetic joints and catheters. They can cause persistent infections and complications in medical settings. - Cells in biofilms are generally more resistant to antibiotic treatment. This is because the extracellular matrix can act as a barrier, limiting the penetration of antibiotics and protecting the microorganisms from the immune system. - The biofilm matrix helps attach cells to a surface and is an important virulence factor. It enables microorganisms to colonize and survive in various environments, contributing to their ability to cause infections. While bacteria are the main constituents of biofilms, other microorganisms, such as fungi and protozoa, and bacteriophage (viruses) may also be part of them

You attended a company picnic last weekend, where various homemade dishes were shared, including potato salad, coleslaw, and a variety of canned foods. Approximately 24 hours after the picnic, you ended up in the ER with severe symptoms such as double vision, drooping eyelids, slurred speech, difficulty swallowing, muscle weakness in your arms and legs, and shortness of breath. Upon examination, the blood work showed a normal complete blood count (CBC) and electrolyte panel, with no indication of other common infections. Stool samples were analyzed, revealing the presence of bacterial toxins and gram-positive, anaerobic, spore-forming rods. Spores were terminal. Based on the history, symptoms, and test results, what is the likely cause of your severe symptoms? a. Escherichia coli b. Bacillus cereus c. Clostridium perfringens d. Clostridium botulinum

d. Clostridium botulinum The symptoms described, such as double vision, drooping eyelids, slurred speech, difficulty swallowing, muscle weakness, and shortness of breath, are consistent with botulism, a serious and potentially life-threatening illness caused by the toxins produced by Clostridium botulinum. The bacterium is gram-positive, anaerobic, and spore-forming with terminal spores, which matches the test results from the stool samples. In this case, the consumption of canned foods at the picnic might have been the source of the C. botulinum infection, as improper canning can create an anaerobic environment that allows the bacterium to grow and produce toxins.

Many clostridial diseases require a(n) ____ environment for their development a. living tissue b. aerobic c. alkaline d. anaerobic

d. anaerobic Many clostridial diseases require an anaerobic environment for their development. Clostridium species are obligate anaerobes, meaning they thrive in environments devoid of oxygen. In the body, these conditions can be found in damaged tissues or wounds, allowing clostridia to grow and produce their potent toxins, leading to disease.

The coagulase test is used primarily to differentiate Staphylococcus aureus from a. streptococci b. micrococci c. Enterococci d. other staphylococci

d. other staphylococci The coagulase test is used primarily to differentiate Staphylococcus aureus from other staphylococci. S. aureus is coagulase-positive, meaning it produces the enzyme coagulase, which causes plasma to clot. In contrast, other staphylococci species, such as Staphylococcus epidermidis, are coagulase-negative and do not produce this enzyme. The ability to produce coagulase is considered a virulence factor for S. aureus, as it helps the bacteria evade the host immune system by forming a protective fibrin barrier around itself.

All of the following are examples of biochemical features that can be used to identify bacteria except a. ability to hydrolyze tryptophan and produce indole. b. ability to ferment glucose. c. ability to oxidize glucose. d. presence of flagella

d. presence of flagella Urea and tryptophan hydrolysis as well as glucose oxidation and glucose fermentation are examples of biochemical (physiological) tests. The presence of flagella is a morphological feature.

The following are examples of virulence factors a. hemolysins b. capsules c. endotoxins & exotoxins d. adhesions e. All of these are examples of virulence factors

e. All of these are examples of virulence factors virulence factors are molecules and strategies enhancing a pathogen to cause disease - aiding in colonization, evasion, & tissue damage such as adhesins, capsules, flagella, Toxins (LPS, cytolysins), and Enzymes (hyaluronidase, lipase, coagulase, oxidase, catalase)

A complication of genital gonorrhea is a. Infertility b. pelvic inflammatory disease c. arthritis d. blindness e. all of these

e. all of these All of these. Gonorrhea, caused by the bacterium Neisseria gonorrhoeae, can lead to a range of complications if left untreated. In women, it can cause pelvic inflammatory disease (PID), which can further result in infertility. Both men and women can develop disseminated gonococcal infection, which can cause arthritis. An infant born to a mother with gonorrhea can be infected during delivery, leading to a condition called ophthalmia neonatorum, which can result in blindness. So, all the listed complications can be associated with gonorrhea.