MICRO102B

• Among the molds, the notable antibiotic producers are Penicillium and Cephalosporium which are the main sources of beta-lactam antibiotics like penicillin and its relatives.

  TRUE. Penicillium and Cephalosporium are indeed notable producers of beta-lactam antibiotics, including penicillin and cephalosporins, respectively. These antibiotics are widely used in medicine to treat bacterial infections.
• Among the bacteria, the actinomycetes, notably Streptomyces species, produce a variety of antibiotics including aminoglycosides (e.g. Streptomycin), macrolides, and tetracyclines.

  TRUE. Actinomycetes, particularly Streptomyces species, are well-known for producing a wide variety of antibiotics, including aminoglycosides (such as Streptomycin), macrolides, and tetracyclines. These antibiotics have been crucial in medicine for treating various bacterial infections.
• The common mastitis pathogens are Staphylococcus aureus and Streptococcus agalactia.

  TRUE. The most common bovine mastitis pathogens include Staphylococcus aureus and Streptococcus agalactiae, S.dysgalactiae, and S.uberis.
• The presence of thermotolerant coliforms nearly always indicates fecal contamination.

  TRUE, Thermotolerant coliforms, such as Escherichia coli (E. coli), are a subgroup of coliform bacteria commonly found in the intestines of warm-blooded animals, including humans. Their presence in water or food samples is typically indicative of fecal contamination, which can pose health risks due to the potential presence of pathogens associated with fecal matter.
• With the great expansion of the poultry industry, the widespread occurrence of salmonellosis has been ranked as one of the most egg-borne bacterial diseases of poultry.

  TRUE. With the significant expansion of the poultry industry, salmonellosis has indeed been ranked as one of the most common egg-borne bacterial diseases of poultry. Salmonella bacteria can contaminate poultry products, including eggs, leading to human infections if the eggs are consumed raw or undercooked.
• Survivors of salmonellosis remain carries for life and can be sources of infection for other birds.

  FALSE. Survivors of salmonellosis typically do not remain carriers for life. While some individuals may shed Salmonella bacteria for a period after recovering from the infection, they usually clear the bacteria from their system within a few weeks to months. However, during the acute phase of the infection, infected birds can shed the bacteria and potentially infect other birds.
• In the water analysis, if coliforms are present, gas is produced and is trapped in the inner vial.

  TRUE. In some water analysis methods, such as the multiple tube fermentation technique, if coliform bacteria are present in the water sample, they ferment lactose or other carbohydrates, producing gas (usually carbon dioxide and sometimes other gases). This gas production is detected by the presence of a gas bubble in the inverted inner vial of the multiple tube fermentation apparatus.
• The number of tubes that form gas is used to estimate the number of coliform organisms in the sample.

  TRUE. In the multiple tube fermentation technique, the number of tubes that form gas is indeed used to estimate the number of coliform organisms present in the sample. This method involves inoculating multiple tubes of lactose broth with varying dilutions of the water sample, and the presence of gas in the tubes after incubation indicates the presence of coliform bacteria. By counting the number of positive tubes, an estimate of the coliform count in the original sample can be obtained.
• The presence of total coliforms may or may not indicate fecal contamination.

  TRUE. While total coliforms can be indicative of fecal contamination, they can also originate from environmental sources like soil and vegetation. Therefore, the presence of total coliforms alone does not always confirm fecal contamination and must be further confirmed by testing for thermotolerant (fecal) coliforms or specific fecal indicators like E. coli.
• The presence of Escherichia coli is definitive proof of fecal contamination.

  TRUE. Escherichia coli is a species of bacteria that is primarily found in the intestines of warm-blooded animals, including humans. Therefore, its presence in water or food samples is considered definitive proof of fecal contamination, as it indicates the presence of fecal material from animals or humans.
• Like the bacteria, fungi need moisture for their growth. Hence, they cannot exist in places like bathroom walls, leather shoes, and bags as those do not contain moisture.

  FALSE. While fungi do require moisture for growth, they can still exist in environments with low moisture levels, such as bathroom walls, leather shoes, and bags. Fungi are capable of surviving in dormant states until conditions become favorable for growth again. Therefore, the statement is false; fungi can exist in various environments, even those with limited moisture.
• Escherichia coli has been used as a marker to indicate the contamination of water and food with human and animal feces.

  TRUE. Escherichia coli is commonly used as an indicator organism to detect the presence of fecal contamination in water and food samples. Since E. coli is primarily found in the intestines of warm-blooded animals, including humans and animals, its presence in water or food samples indicates the potential presence of fecal material and associated pathogens.
• One measure of milk quality is the bacterial content of raw and pasteurized milk.

  TRUE. The bacterial content of milk is a critical indicator of its quality as high levels of bacteria can indicate contamination and potential health risks. Pasteurization, a process of heating milk to kill harmful bacteria, aims to reduce bacterial content and enhance milk safety.
• Standard Plate Count (SPC) refers to the bacterial content of raw and pasteurized milk.

  TRUE. The Standard Plate Count (SPC) is indeed a measure of the bacterial content in both raw and pasteurized milk. It quantifies the total number of viable aerobic bacteria present in a milk sample, providing a standard measure for assessing milk quality and safety.
• Pasteurized Grade A milk is required to have less than 20,000 bacteria/ml. by standard plate count.

  TRUE. Pasteurized Grade A milk is typically required to meet certain quality standards, including having a bacterial count of less than 20,000 colony-forming units (CFUs) per milliliter as determined by the Standard Plate Count (SPC). This standard is a common regulatory requirement to ensure the safety and quality of pasteurized milk.
• The technique used in the bacteriological analysis of water is the Most Probable Number (MPN) method, also known as the Multiple Tube Fermentation Technique which uses screw-capped tubes containing sterile broth medium.

  TRUE. The Most Probable Number (MPN) method, which is also referred to as the Multiple Tube Fermentation (MTF) technique, uses screw-capped tubes that contain sterile broth medium. The tubes contain an inverted inner vial (a Durham tube) for gas collection. Sample is added to the tubes and incubated.
• Standard Plate Count (SPC) is a measure of the number of bacteria in milk which has a strong relationship with the keeping quality of the milk .

  TRUE. The Standard Plate Count (SPC) is indeed a measure of the total number of bacteria in milk, and it has a strong relationship with the keeping quality or shelf life of the milk. Higher SPC values generally indicate a higher bacterial load, which can lead to faster spoilage and reduced shelf life of the milk.
• The term coliforms refers to a large group of Gram (-) negative, rod-shaped bacteria that share several characteristics.

  TRUE. The term "coliforms" does refer to a large group of Gram-negative, rod-shaped bacteria that share several characteristics, including the ability to ferment lactose to produce acid and gas within 48 hours at 35-37°C. These characteristics make them useful indicators of fecal contamination in water and food.
• Total coliforms include thermotolerant coliforms and bacteria of fecal origin, as well as some bacteria that may be isolated from environmental sources.

  FALSE. Total coliforms include both fecal coliforms (such as Escherichia coli) and non-fecal coliforms (such as those found in soil or vegetation), but they do not include thermotolerant coliforms as part of their definition. Thermotolerant coliforms are a subset of fecal coliforms and are specifically indicative of recent fecal contamination.
• In the CAMP test, Staphylococcus aureus will produce the arrowhead pattern.

  FALSE. In the CAMP test, Staphylococcus aureus does not produce the arrowhead pattern. This test is typically used to identify the production of the CAMP factor, which enhances the hemolytic activity of beta-hemolytic Streptococcus species. When the CAMP factor is present, it synergizes with the beta-hemolysin produced by certain Streptococcus species, resulting in an arrowhead-shaped zone of enhanced hemolysis adjacent to the streak of Staphylococcus aureus.
• In the CAMP test, the plates should be incubated in an anaerobic environment because Streptococci turns Gram-positive in the absence of oxygen.

  FALSE. In the CAMP test, plates should be incubated aerobically, not anaerobically, as the test relies on the production of the CAMP factor, which enhances hemolysis by beta-hemolytic Streptococcus species. Streptococci remain Gram-positive regardless of oxygen availability, and the test is conducted aerobically to allow for proper expression of the CAMP factor.
• Salmonella is a Gram-positive coccus and is an inhabitant of the lower gut.

  FALSE. Salmonella is a Gram-negative bacterium and typically exists as a rod-shaped (bacillus) bacterium, not a coccus. Additionally, Salmonella is known to inhabit the lower intestines of animals, including humans, rather than being exclusively a gut inhabitant.
• Total coliforms refers to a large group of Gram-negative, oval-shaped bacteria.

  FALSE. Total coliforms encompass a broad group of Gram-negative, rod-shaped bacteria, not oval-shaped bacteria. The term "total coliforms" includes various genera such as Escherichia, Klebsiella, and Enterobacter, among others, which are typically rod-shaped or bacilli. Oval-shaped bacteria are not typically included in the definition of total coliforms.
• Due to its high nutritive value, milk is an ideal medium for the rapid multiplication of bacteria, particularly under hygienic production and storage at ambient temperature.

  FALSE. While milk does indeed provide a favorable environment for bacterial growth due to its high nutritive value, proper hygiene practices during production and storage, along with refrigeration, inhibit the rapid multiplication of bacteria. Hygienic production and refrigerated storage are essential measures to minimize bacterial growth and maintain milk quality and safety.
• Yeasts are microscopic, consisting of unicellular cells that reproduce by budding.

  TRUE. Yeasts are indeed microscopic fungi that consist of unicellular cells, and they typically reproduce by a process called budding, where a new cell forms as an outgrowth from the parent cell.
• Regardless of their shape and size, fungi digest their food externally releasing hydrolytic enzymes into their immediate surroundings.

  TRUE. Fungi typically digest their food externally by releasing hydrolytic enzymes into their immediate surroundings, regardless of their shape and size. These enzymes break down complex organic molecules into simpler forms that can be absorbed by the fungi for nutrition.
• Molds occur in long filaments known as hyphae which grow by apical extension.

  TRUE. Molds do indeed consist of long filaments called hyphae, which grow through apical extension. This means they elongate from the tip, allowing the mold to expand and spread.
• Pathogenic fungal agents will grow in the presence of antibiotics whereas the growth of nonpathogenic fungi is inhibited.

  FALSE. Pathogenic fungal agents can be inhibited by antibiotics, just like nonpathogenic fungi. Antibiotics target bacterial growth, not fungal growth, so they generally don't affect fungi in the same way.
• Fungi are chemoheterotrophs, and, like bacteria, they absorb nutrients rather than ingesting them.

  TRUE. Fungi, like bacteria, are chemoheterotrophs, meaning they obtain energy and carbon from organic compounds. They absorb nutrients from their environment rather than ingesting them.
• Ideally, raw milk should contain more than 5,000 bacteria/ml.

  FALSE. Ideally, raw milk should contain fewer than 100,000 bacteria/ml. High levels of bacteria in raw milk can indicate poor hygiene during milking or storage, which may pose health risks.
• The maximum legal limit (raw milk) for SPC is 200,000/ml.

  FALSE. The regulatory limit for SPC is 100,000 bacteria/ml of milk.
• Hemolysin is one example of an enzyme secreted by bacteria.

  TRUE. Hemolysin is indeed an example of an enzyme secreted by certain bacteria. It works by breaking down red blood cells, allowing the bacteria to obtain nutrients from the released contents.
• The adhesive (scotch tape) method is an excellent technique for mount rapid sporulating fungi because it keeps more of the reproductive structures intact.

  TRUE. The adhesive (scotch tape) method is indeed an excellent technique for mounting rapid sporulating fungi because it helps preserve more of the reproductive structures, such as spores, intact on the tape surface, allowing for easier observation and analysis under a microscope.
• Blood and most of our cells contain catalase.

  TRUE. Catalase is indeed present in blood and most of our cells. It plays a crucial role in breaking down hydrogen peroxide into water and oxygen, which helps protect cells from damage caused by reactive oxygen species.
• When hydrogen peroxide is poured over an open wound, the catalase instantly converts hydrogen peroxide into water and oxygen.

  TRUE. When hydrogen peroxide is poured on an open wound, the catalase instantly converts hydrogen peroxide into water and oxygen – these breakdown products generate the fizzing reaction we see on the skin. The fizzing does actually help remove and clear debris from the open wound.
• Like Staphylococcus, Escherichia coli is also catalase positive.

  TRUE. Like Staphylococcus, Escherichia coli is also catalase positive.
• Strains of Salmonella that produce hydrogen sulfide will form black-centered colonies.

  TRUE. Salmonella strains that produce hydrogen sulfide will indeed form black-centered colonies on certain types of media, such as Hektoen enteric agar. This characteristic is one of the diagnostic features used in identifying Salmonella bacteria.
• The golden appearance of Staphylococcus aureus colonies in blood agar plate is the root word of its bacterial name- "aureus" meaning golden.

  TRUE. The golden appearance of Staphylococcus aureus colonies on a blood agar plate is indeed the origin of its name. "Aureus" is Latin for "golden," referring to the characteristic golden or yellow color of its colonies.
• When Simmon citrate is inoculated with E.coli, the medium remains green.

  FALSE. When E. coli is inoculated onto a Simmons citrate agar, the medium typically remains green. E. coli is not capable of utilizing citrate as a sole carbon source, so it does not produce significant alkaline byproducts, which would cause the medium to turn blue. Instead, it tends to maintain the original green color of the agar.
• MRVP is a selective isolation medium for the growth and maintenance of pathogenic and non-pathogenic fungi.

  FALSE. The MRVP (Methyl Red Voges-Proskauer) test is not a selective isolation medium for fungi; instead, it is a biochemical test used to differentiate between bacteria based on their metabolic pathways. Specifically, it distinguishes between bacteria that produce mixed acids (resulting in a red color) and those that produce acetoin (resulting in a positive Voges-Proskauer reaction, giving a pink color). It's not used for fungi at all.