Clinical Microbiology Final Exam Review

Characteristics of Moraxella include

- Gram-negative- Cocci (often Diplococci) or Short Rods- Non-endospore forming, Non-Motile- Non-hemolytic Exception: Some strains of M. Lacunata- Non-encapsulated-Nutritionally fastiduous (Glycine or Arginine) Optimum growth temp.: 33-35°C- Aerobes- Catalase-Positive- Oxidase-Positive

The development of staphylococcal infection is determined by

-Virulence of the strain- size of inoculum- Status of host's immune system All of the above

What McFarland standard provides turbidity comparable to that of a bacterial suspension containing approximately 1.5 × 108 colony-forming units (CFU)/mL?

0.5

What is the recommended contact time for most disinfectants in a mycobacteriology laboratory?

10- 30 mins

Generally, microbiologists observe the colonial morphology of organisms on primary culture after how many hours of incubation?

18-24 hours

What is the optimum culture incubation time for most mycobacteria associated with human disease?

2-6 weeks

Cultures for Mycoplasma pneumoniae should be incubated for

3-4 weeks

Some bacteria grow at 25° C or 42° C, but diagnostic laboratories routinely grow pathogenic bacteria at what temperature?

35 C

What is the purpose of the digestion-decontamination processing of specimens submitted for mycobacterial culture?

To liquefy the sample through digestion of the proteinaceous material and to allow the chemical decontaminating agent to contact and kill the non-mycobacterial organisms

What disease produced by a Salmonella spp. is a severe form of enteric fever?

Typhoid fever

A young, healthy patient goes into the hospital for reconstructive knee surgery and spikes a fever the day after surgery. The doctor finds the patient has a nosocomial infection with methicillin-resistant Staphylococcus aureus (MRSA). What antibiotic should the doctor use to treat this patient?

Vancomycin

What is VRE?

Vancomycin-resistant Enterococcus

At-risk groups for contracting walking pneumonia include all the following, except

Very young children

Which occupation would hold highest risk of glanders?

Veterinarian

In terms of MIC microdilution trays, a skipped well occurs

When there is growth at higher concentrations and no growth at one or more of the lower concentration wells

Which of the following is considered a better specimen for anaerobic culture than a swab?

Aspirate

What organism is associated with pneumonia in patients with cystic fibrosis or chronic granulomatous disease (CGD)?

Burkholderia cepacia

What is the causative agent of glanders?

Burkholderia mallei

Which nonfermenter is considered by government agencies to be a potential bioterrorist agent?

Burkholderia mallei

Preferred samples for plating onto Ashdown media include throat, rectal, or sputum samples. Disease presentation can range from subclinical to disseminated disease. This infection is endemic in Southeast Asia. Which organism is being sought?

Burkholderia pseudomallei

What organism causes melioidosis?

Burkholderia pseudomallei

What substances do nonfermenters fail to ferment in traditional media?

Carbohydrates

This bacterial state occurs when a host harbors a disease-causing organism, but does not show signs of disease.

Carrier State

Mycoplasmas are different from most other bacteria because they do not have a

Cell wall

What organism is an opportunistic pathogen that strikes the immunocompromised patient with neutrophil deficits and produces a violet pigment on nonselective agar?

Chromobacterium violaceum

In addition to cystic fibrosis patients, patients with which other disease are at greatest risk of death due to fulminant lung infections and/or bacteremia caused by B. cepacia?

Chronic granulomatous disease

A microbiologist is reading stool culture plates. She is looking for enteric pathogens on the MAC plate. What do they look like?

Clear, colorless colonies

All of the following are non-spore-forming, anaerobic, gram-positive bacilli, except

Clostridium

All of the following organisms are found on the skin under normal conditions, except

Clostridium

An anaerobic culture reveals colonies with a double zone of hemolysis on SBA plate. There was no growth on plates incubated aerobically. The Gram stain of that organism was a boxcar-shaped, gram-positive bacillus. What organism is this?

Clostridium perfringens

What organism mostly commonly causes gas gangrene?

Clostridium perfringens

Which animals are a common source of Salmonella serotypes?

Cold-blooded animals (fish)

In the microbiology laboratory, this instrument is routinely used to examine smears for structures that are too small to be seen with the unaided eye.

Compound microscope

Why should laboratory professionals look for contamination of a specimen by normal microbial flora?

Contamination of specimens with normal flora that are not collected from sterile sites diminishes the value of the culture studies.

If a laboratory uses hazardous chemicals, it must

A laboratory must maintain a current inventory of hazardous chemicals, and the MSDSs for those particular chemicals according to 29 CFR Part 1910, Subpart 2, Toxic and Hazardous Substances (OSHA).

Neonates and individuals who are immunocompromised are at risk for developing meningitis if they contract which organism?

Elizabethkingia meningoseptica

A patient is brought to the emergency room with the following symptoms: body temperature of 102° F, low blood pressure, elevated WBC, and disseminated intravascular coagulation. This person has gram-negative rods growing in the blood. What is responsible for these symptoms?

Endotoxin

All of the following virulence factors are associated with Staphylococcus aureus, except

Endotoxins

A microbiologist notices growth on a LJ slant that is a buff color, rough, and seems arranged in a cord. It has taken these organisms 4 weeks to grow. What is the most probable organism?

M. tuberculosis

A green colony with a black center was isolated and presumptively identified as a Salmonella spp. The organism was serotyped with polyvalent antisera; however, the antisera tested negative for all antigens. What is the next course of action?

Make a suspension, and heat to 100 degree centigrade for 10 min.

The three regions of the lipopolysaccharide include all the following, except

Mycolic Acid

If a newborn has symptoms of meningitis but the cerebrospinal fluid (CSF) is negative for both Gram stain and a routine culture, what organisms should be suspected?

Mycoplasma hominis and Ureaplasma urealyticum

What two organisms are associated with urogenital tract infections but have also been isolated from asymptomatic individuals?

Mycoplasma hominis and Ureaplasma urealyticum

What infectious agent causes the condition primary atypical pneumonia?

Mycoplasma pneumonia

What substance produced by the Salmonella spp., which cause gastroenteritis, has been implicated as a significant virulence factor?

Enterotoxin

What are the staphylococcal products that cause diarrhea and vomiting in humans?

Enterotoxins (produced by staph aureus)

The primary reservoir for staphylococci is

Nares

What disease is produced by Group A streptococci that are characterized by a rapidly progressing inflammation and necrosis of the skin, subcutaneous fat, and fascia?

Necrotizing fasciitis

What time frame is suitable for blood draws for serologic testing to diagnose Mycoplasma infections?

Onset of symptoms and 2 to 3 weeks later.

What are the primary antigens used in serologic grouping of salmonellae?

Flagellar H antigen and somatic O antigen

What disease does Clostridium perfringens cause?

Food poisoning

In the carrier state, where are pathogenic salmonella carried?

Gallbladder

For the most part, all Enterobacteriaceae are positive for which biochemical reactions?

Glucose, catalase, and reduce nitrates to nitrites

Characteristics of most members of the family Flavobacteriaceae

Gram-negative rods, are non-flagellated, non-motile or motile by gliding and non-spore-forming. Colonies are non-pigmented or pigmented by carotenoid and/or flexirubin types of pigments

The density of the bacterial colony can be described by all the following, except

Ground glass

What is one of the most common diseases caused by streptococci?

Group A Strep

What are scotochromogens?

Acridine orange

What is the purpose of a capsule?

Act as a virulence factor in helping the pathogen evade phagocytosis

An immunosuppressed patient notices sinus tracts that are draining pus. He also notices that there appear to be small, hard "nuggets" in the pus. What disease is he most likely suffering from?

Actinomycosis

Two serious complications of an infection with Group A streptococci are

Acute Glomerulonephritis and Rheumatic fever

In this method of antimicrobial susceptibility testing, specific volumes of various concentrations of antimicrobial solutions are dispensed into premeasured volumes of molten and cooled agar, which is subsequently poured into standard Petri dishes. Organisms are inoculated onto the plate. What type of antimicrobial susceptibility testing is this?

Agar dilution

What evidence indicates the presence of anaerobes in cultures?

All- foul odor from opening anaerobic jar/bag, growth on anaerobic plates, but not sheep blood(SBA) plates incubated in the CO2 incubator, and colonies on kanamycin-vancomycin laked blood agar(KVLBA) that fluorescence brick-red under UV.

How are suspected colonies of anaerobes processed?

All- gram stain morphology and reaction is observed, an aerotolerance test is set up, and a pure culture/subculture plate is inoculated and appropriate disks are added.

You are working in a microbiology laboratory and receive a sputum for culture. You perform a Gram stain on the sputum and get the following results: 3+ gram-positive cocci, greater than 25 epithelial cells/10× field, less than 10 neutrophils/10× field, and heavy mucus. What do these results indicate?

An unacceptable specimen and workup that should be limited to basic identification of bacteria

Before performing a phlebotomy, the phlebotomist will clean the area on a patient's arm with a substance before inserting the needle. This substance is called a(n)

Antispetic

Who was considered the father of protozoology and bacteriology?

Antony van Leeuwenhoek

What classifies an organism as a multidrug-resistant Mycobacterium tuberculosis

Organisms resistant to at least isoniazid and rifampin.

What biochemical test will differentiate nonfermenters from Enterobacteriaceae (except Plesiomonas)?

Oxidase

Incidence is

Incidence is defined as the number of new cases of disease over a period of time.

Healthy people are colonized by many different bacteria in many different sites. These bacteria are referred to as

Indigenous flora

On a breakpoint panel, when there is growth in the low concentration but no growth in the high concentration, the isolate is

Intermediate

Dissemination of a pathogen is

Invasion of a pathogen allows the microbe to take advantage of the host's transport system (the blood) and seek out other areas that can be infected. This occurs only if the pathogen can elude the host's immune system during this journey. Invasion is when a pathogen penetrates and grows in tissues. Intracellular multiplication of a pathogen occurs when an organism can survive phagocytosis. When a pathogen shifts key cell-surface antigens, it is evading a host's immune system.

Streptococcus agalactiae is a significant cause of

Invasive disease of the newborn

A microbiologist is reading the plates from a sputum culture. On the sheep blood agar (SBA), the microbiologist sees flat spreading colonies with a metallic sheen. On cetrimide agar, a fluorescent green color is seen in the medium with clear colonies. On MacConkey, medium clear colonies are seen that have a fruity or grapelike odor. What is the most likely organism?

P. aeruginosa

The three nonfermenters that make up the majority of isolates routinely seen in clinical laboratories include all the following, except

P. putida 3 species: Psuedomonas aeruginosa, Acinetobacter spp., and Stenotrophomonas maltophilia

What bacterium produces swarming colonies on nonselective media, such as sheep blood agar (SBA)?

P. vulgaris and P. mirabilis

All the following antimicrobial agents are used to treat mycoplasma infections, except

Penicillin

Which of the following is the drug of choice for treating most streptococcal infections?

Penicillin

All of the following are virulence factors associated with Group A Streptococcus, except

Peptidoglycan

This constituent of a gram-positive cell wall absorbs crystal violet but is not dissolved by alcohol, thus giving the gram-positive cell its characteristic purple color.

Peptidoglycan

Streptococcus pneumoniae causes all the following infections, except

Pharyngitis

A night technician is working in microbiology when a cerebrospinal fluid (CSF) specimen comes in. Almost simultaneously, the technician is called to the emergency department to draw blood on seriously injured car crash victims. How would the technician store the CSF until time permits to work on the CSF specimen?

Place the specimen in a 35° C incubator for 6 hours

The technician in the laboratory has received a specimen that is rejected. The technician calls the physician and tells the physician the specimen is unacceptable and the reason why. The physician insists that the culture needs to be performed on this unacceptable culture. What should the technician do?

Plate the culture, but include a comment explaining the potentially compromised test results.

The primary pathogens of the Enterobacteriaceae include all the following, except

Proteus mirabilis

The function of a cell wall is to

Provide rigidity and strength to the exterior of the cell.

Production of exotoxin A and several proteolytic enzymes and hemolysins are factors that contribute to the pathogenicity of which organism?

Pseudomonas aeruginosa

What Pseudomonas sp. is the nonfermenter that is the leading cause of nosocomial pneumonia and bacteremia?

Pseudomonas aeruginosa

Which nonlactose-fermenting organism, that rarely causes human infection, grows poorly at 35°C; however, grows optimally between 20°C and 25°C?

Psychrobacter immobilis

Acquired mechanisms of resistance are those that

Result form acquisition of DNA by acquisition of extrachromosomal DNA

A young man goes to his physician complaining of large, raised, suppurative abscesses on his neck. The man denies having a fever or the chills. What is the name of the lesions on his neck, and what organism causes this type of lesions?

S. aureus and furuncles

Infections by this organism are predominantly hospital acquired, and some predisposing factors include catheterization, medical implantation, and immunosuppressive therapy.

S. epidermidis

The two species of coagulase-negative staphylococci most often isolated in clinical laboratories are

S. epidermidis and S. saprophyticus

What organism possesses the Vi antigen?

Salmonella typhi

When Mycoplasma hominis invades the upper genitourinary tract, it can cause the following:

Salpinitis/Pyelonephritis/PID

In the laboratory, the clinical microbiologist is responsible for all the following, except

Selecting treatment for patients

A DNase-positive member of the family Enterobacteriaceae is suggestive of

Serratia

What toxin does Shigella spp. produce?

Shiga toxin

Bacillary dysentery caused by this organism is marked by penetration of intestinal epithelial cells following attachment of the organisms to mucosal surfaces, local inflammation, shedding of the intestinal lining, and formation of ulcers that follow the epithelial penetration. What is this organism?

Shigella

Why would normal flora isolating from immunosuppressed patients undergo antimicrobial susceptibility testing?

Species usually viewed as normal florae may be responsible for an infection in an immunosuppressed patient.

Later in the evening, after attending a family reunion, several family members went to the emergency department after experiencing nausea, vomiting, abdominal pain, and severe cramping. The menu included fried chicken, hot dogs, hamburgers, potato salad, deviled eggs, éclairs, and cheesecake. The symptoms appeared about 4 hours after eating. What is the most probable explanation for these symptoms?

Staphylococcal food poisoning

A 20-year-old woman goes to her physician complaining of burning upon urination, frequency, and general malaise. Her physician orders a urine culture, which grew 25,000 colony-forming units (CFU)/mL of a catalase-positive, coagulase-negative, novobiocin-resistant gram-positive coccus. What is the most likely pathogen?

Staphylococcus saprophyticus

The chemical or physical method that destroys all forms of life is called

Sterilization

The specimen of choice for detecting gastrointestinal pathogens is

Stool

What causes the red spreading rash in scarlet fever?

Streptococcus pyogenes

What is the hemolysin responsible for hemolysis on SBA by Group A streptococci incubated anaerobically?

Streptolysin O

Which antibiotic inhibits folate synthesis, providing the essential precursor molecule, pyridine thymidylate, needed in DNA synthesis?

Sulfamethoxazole

What substances do organisms that use oxygen have to protect themselves from superoxide anions?

Superoxide dismutase and catalase.

This ongoing process helps public health and health care officials recognize outbreaks, upward trends of infections, and positive effects of interventions.

Surveillance

Important factors that must be considered when determining whether antimicrobial susceptibility testing is warranted include

The body site from which the organism was isolated The presence of other bacteria and the quality of the specimen from which the organism was grown The host's status All the above

The relative concentration of bacteria on culture plates is directly proportional to

The concentration in which they are present in the clinical specimen

Why is it that most cases of salmonella food poisoning are not treated with antibiotics?

The disease is self-limiting and will subside on its own.

A primary tenet of antimicrobial therapy is to use

The least toxic agents The most cost-effective agents The most clinically effective agents All of the above

When reading broth microdilution MIC testing, the MIC for a particular drug is

The lowest concentration showing no obvious growth

Why can direct microscopy not be used to provide a presumptive identification of the enteric bacteria?

The microscopic characteristics are indistinguishable from other gram-negative bacteria.

As a general guideline, it is suggested that within a particular antimicrobial class, primary (group A) agents should be reported first and secondary (group B) agents should be reported only if

The patient cannot tolerate the primary agents

Intrinsic mechanisms of resistance are

They are innate characterisitics of the microorganim and are transmitted to progeny vertically

Why do staphylococci spread so easily when infecting the skin?

They produce hyaluronidase, which hydrolyzes hyaluronic acid present in the intracellular ground substance that makes up connective tissue

Why should antimicrobial susceptibility testing of normal flora isolates or isolates likely to represent contamination or colonization not be performed?

This may encourage a physician to treat a normal condition

What bacterium is the causative agent of the plague?

Yersinia pestis

The resulting disease from this route of transmission is a disease of animals that is transmitted to humans.

Zoonotic

How are mycobacterial infections typically transmitted?

aerosol from soil, dust or water, by ingestion,

Universal/Standard Precautions require that

all blood and other body fluids be treated as if they are infectious.

An iatrogenic infection is one that

an infection after medical or surgical management, whether or not the patient was hospitalized

Diabetics may sometimes be infected with their own resident flora. This type of infection is called

an opportunistic infection.

All of the following are poor prognostic factors associated with Pseudomonas aeruginosa bacteremia, except

anemia

What is an anaerobe?

any organism that is able to live without oxygen

What is an obligate anaerobe?

are organism which can only live in environments which lack oxygen.

What are photochromogens?

are slow growing, and produce a yellow-orange pigment when exposed to light.

Efflux pumps

are transport proteins involved in the extrusion of toxic substrates (including virtually all classes of clinically relevant antibiotics) from within cells into the external environment.

Enriched media

contain the nutrients required to support the growth of a wide variety of organisms, including some fastidious ones.

When transporting specimens for Mycoplasma culture to the laboratory, extreme care must be taken so that the specimen does not

dry out

All of the following are approaches to treating anaerobic infections, except

enzyme inactivators.

Elizabethkingae meningosepticum causes all the following diseases, except

gastroenteritis

All of the following are traditional characteristics used to identify mycobacteria, except

gram stain results

All of the following are symptoms of salmonellosis that may appear 8 to 36 hours after ingestion of contaminated food, except

headache symptoms: nausea, vomiting, and watery diarrhea

Middlebrook 7H10 and 7H11 media are enriched with all of the following, except

heme

The major virulence factor for Streptococcus pneumoniae is

polysaccharide capsule

The following describes the log phase of bacterial growth:

populations are doubling under optimum conditions.

The purpose of transport media is to

preserve a specimen and minimize bacterial overgrowth from the time of collection to the time it is received at the laboratory to be processed.

A microorganism that is a unicellular organism and lacks a nuclear membrane and true nucleus belongs to which classification?

prokaryotic cell

The following species, P. aeruginosa, P. fluorescens, Pseudomonas putida, P. veronii, Pseudomonas monteilii, and Pseudomonas mosselii, all produce a water-soluble, yellow-green pigment called:

pyoverdin(only P. aeruginosa produces pyocyanin)

Why is clean-catch midstream urine used for a urine culture as opposed to a clean-catch urine?

reduces the risk of the sample being contaminated with bacteria from: your hands. the skin around the urethra, the tube that carries urine out of the body.

Microaerophiles are bacteria that grow

requires oxygen to survive, but requires environments containing lower levels of oxygen than that are present in the atmosphere

An outbreak occurs when

sudden rise in the number of cases of a disease

A zone of inhibition is

the area around the antibiotic disk where the bacteria cannot not grow

An index case is

the first identified case in a group of related cases of a particular communicable or heritable disease.

The minimal inhibitory concentration (MIC) is

the lowest concentration of an antimicrobial ingredient or agent that is bacteriostatic (prevents the visible growth of bacteria).

Capnophiles are bacteria that grow

thrive in the presence of high concentrations of carbon dioxide.

A young, healthy woman was rushed to the hospital with a high fever, hypotension, and shock. She had not been feeling well that day, but her condition progressively worsened throughout the day. She was feeling fine until a couple of days after she started menstruating. What condition could this woman be exhibiting?

toxic shock syndrome

Selective media

used for the growth of only selected microorganisms

The ability of an organism to produce disease in an individual is called

virulence genes

What is the antigen used in the purified protein derivative (PPD) skin test?

A purified protein from the cell wall of M. tuberculosis

In what staining procedure does carbolfuchsin penetrate the bacterial cell wall through heat or detergent treatment?

Acid-Fast Staining

Which organism may be mistaken for a lactose fermenter on MacConkey agar because of colonies exhibiting a purple hue on the media?

Acinetobacter spp

Penicillins, cephalosporins, monobactams, and carbapenems all have this ring in their structure that is responsible for inhibiting the transpeptidation reaction, resulting in bacterial lysis and cell death.

B-Lactam

Which species of Burkholderia is the one most commonly found in clinical specimens?

B. cepacia

Material from an intestinal abscess produces gray colonies with a brown color in the area around the colonies on a BBE plate incubated anaerobically. There is also a dark precipitate in the medium in the areas of heavy growth. A Gram stain of the colonies reveals gram-negative coccobacilli. What is the presumptive identification of this organism?

B. fragilis

Antibiotics work by targeting all of the following, except

Bacterial plasmid DNA

What is the single most important piece of equipment in a mycobacterial laboratory?

Biological safety cabinet

What disease does Clostridium botulinum cause?

Botulism

An Older adult patient in a nursing home is recovering from bacterial pneumonia. The patient has been on a lengthy regiment of antimicrobial agents. Subsequently, the patient is diagnosed with pseudomembranous colitis. What organism is the most likely cause?

C. difficile

Which of the following stains is used to enhance the visibility of mycoplasma-like colonies?

Dienes stain

Differential media

Differential media allow grouping of microbes based on different characteristics demonstrated on that medium. Nonselective media support the growth of most nonfastidious microbes. Selective media support the growth of one type or group of microbes, but not another. Enriched media contain growth enhancers that are added to nonselective agar to allow fastidious organisms to flourish.

An upper respiratory specimen contains many indigenous organisms which may be time consuming, cost prohibitive, and insurmountable. What should the microbiologist do?

Differentiate the potential pathogens from the "usual" inhabitants of the upper respiratory tract and direct the diagnostic workup only to potential pathogens.

After using the phone, the laboratory tech sprayed the receiver with a chemical spray. This process will kill a defined scope of microorganisms. What is this process called?

Disinfection

Enterotoxigenic and enteroinvasive are terms often linked to which of the following bacterial species?

E. Coli

Which organism is the most common cause of urinary tract infections (UTIs) in humans?

E. Coli

What diarrheal pathogen can produce a disease that can lead to hemolytic-uremic syndrome?

E. Coli 0157

All of the following are categories of diarrhea-causing Escherichia coli, except

EMEC.

This disease is slowly progressive, malignant, and, if untreated, life threatening. It is characterized by skin lesions and progressive, symmetric nerve damage. Lesions of the mucous membranes of the nose may lead to destruction of the cartilaginous septum, resulting in nasal and facial deformities. What disease is this?

Hansen's disease

When would it be appropriate for an institution to routinely test group C agents?

If a particular institution routinely encounters large numbers of isolates resistant to group A and group B agents

This class of antibodies is usually found as a pentamer.

IgM

What are the effects of the α-hemolysin produced by Staphylococcus aureus?

It lyses red blood cells, damages platelets and macrophages, and can cause severe tissue damage.

All of the following procedures should be performed on clinical specimens to recover anaerobic bacteria, except

Kinyoun stain

In this type of antimicrobial susceptibility test, a McFarland 0.5 standardized suspension of bacteria is swabbed over the surface of a Mueller-Hinton agar plate, and paper disks containing single concentrations of each antimicrobial agent are placed onto the inoculated surface. What is the name of this test?

Kirby-Bauer

BONUS: What enteric organism may produce a blue-violet pigment on non-blood-containing media?

Kluyvera

The initial screening of gram-negative rods is done by testing for the use of this carbohydrate.

Lactose

When performing a Gram stain on a gram-negative organism, the crystal violet is absorbed into this outer cell wall layer, and then washed away with the acetone alcohol. What is the main component of the outer layer of the cell wall?

Lipopolysaccharide

What media are recommended for routine culturing of specimens for the recovery of acid-fast bacilli?

Lowenstein-Jensen and mycobacterial growth indicator tube

What is the cellular structure that Streptococcus pyogenes relies primarily on for its virulence?

M protein

What Mycobacterium spp. fails to grow in vitro?

Mycobacterium leprae

All the following activities must occur for phagocytosis to take place and be effective in host defense, except

Migration of lymphocytes to the area of infection (chemotaxis)

The stomach can be considered a first line of defense against microbial infections because

Most microorganisms are susceptible to the acid pH of the stomach.

In what single setting does Stenotrophomonas maltophilia typically produce disease?

Nosocomial settings

When designing a mycobacterial laboratory, the designers should include all the following engineering controls to keep the workers safe, except

inside air vents to outside

What is a porin?

is an outer membrane protein that forms a water-filled channel. -Allows for passive diffusion of nutrients and waste, but has size-restriction to prevent passage of larger toxins.

Gamma (γ)-hemolysis is

lack of hemolysis in the area around a bacterial colony

Oxacillin-resistant Staphylococcus aureus is called

methicillin-resistant Staphylococcus aureus and is usually referred to by the acronym MRSA.

The natural habitat of Chryseobacterium sp. can best be described as the:

natural environment.

Where are the viridans streptococci constituents of the normal microbiota?

normal flora of the upper respiratory tract, the female genital tract, and the gastrointestinal tract. (all of the above)

Which of these bacteria cannot grow in the presence of oxygen?

obligate anaerobes

What constituent of LJ medium is added to suppress the growth of gram-positive bacteria?

oleic acid

Which of the following methods is used to determine the presence of growth in mycoplasma broth media?

pH indicators such as phynol red.