WATER MICROBIOLOGY AND WATER QUALITY FLASHCARDS (Pharmacy Microbiology)

60 QA-style flashcards covering water microbiology, water quality, sampling, testing methods, and pharmaceutical water standards based on the provided lecture notes.

What are the four visual characteristics that define acceptable drinking water?

Clear, colorless, odorless, and without disagreeable taste; and free from pathogenic organisms.

What percentage of the total cell mass of a bacterium is water typically?

80% or more.

Why is water important to bacterial metabolism beyond being a solvent?

It serves as a medium for biochemical reactions and a carrier for nutrients and wastes.

What structures help microorganisms survive desiccation?

Spores and capsules.

What are the fundamental uses of water highlighted in the notes?

Domestic, industrial, and agricultural uses (pharmaceutical water must be very pure).

How should water used in pharmaceutical preparations be characterized?

Free of microbial and other contaminants.

What types of microorganisms populate fresh waters?

Heterotrophic bacteria, aquatic fungi, and protozoa.

Name some bacteria commonly found in relatively unpolluted freshwaters.

Pseudomonas, Serratia, Chromobacterium, Acinetobacter, Achromobacter, Flavobacterium, Alcaligenes, Micrococcus.

What kinds of bacteria are typically found in soil-polluted waters?

Spore-bearing bacilli (Bacillus, Clostridium), Coli-aerogenes group, nitrifying bacteria.

Which intestinal-origin organisms are important fecal indicators in water?

E. coli, Streptococcus faecalis, Proteus spp., Clostridium perfringens.

Which protozoa are of major concern in water microbiology due to chlorine resistance?

Giardia and Cryptosporidium.

What diseases are caused by Giardia and Cryptosporidium?

Giardiasis and cryptosporidiosis.

Name several waterborne infectious diseases of bacterial origin mentioned in the notes.

Cholera, bacillary dysentery, leptospirosis, typhoid, paratyphoid.

What are the key components of water quality as defined in the slides?

Physical, chemical, and biological characteristics and the standards (WQS) used for comparison.

Which organism is a classic fecal indicator used for detecting recent fecal contamination?

Escherichia coli.

What are the two broad approaches to evaluating microbial content in pharmaceutical products?

Culture methods and non-culture methods.

What is the Total Viable Count (TVC) used for in water analysis?

Estimating the number of viable bacteria by plate counting.

Which two incubation temperatures are used for TVC to differentiate saprophytes from potential pathogens?

22°C and 37°C.

What is the aim of the presumptive coliform test?

Determine the most probable number (MPN) of coliforms per 100 mL as an indicator of fecal contamination.

What are the two methods used for the presumptive coliform test?

Multiple tube method and membrane filtration method.

In the multiple-tube presumptive test, what indicates a positive result?

Gas production in lactose broth tubes (Durham tubes).

Name some media used in presumptive coliform testing.

MacConkey broth, Lauryl tryptose broth, and minerals modified glutamate medium with lactose (and bromocresol purple).

How does the membrane filter presumptive test work?

Filter the sample through a bacteria-proof membrane and culture the filter on appropriate medium for 15–24 hours.

What constitutes a presumptive positive result in lactose fermentation tests?

Gas production (and sometimes acid production) in the tubes.

What is the key criterion for unchlorinated water regarding coliforms per 100 mL?

More than 5 coliform bacilli per 100 mL indicates poor quality for drinking.

What is the criterion for chlorinated water regarding viable coliforms?

Should have no viable coliforms present.

What are the three main types of packaged water products?

Industrial water, compendial waters, and packaged drinking water.

How is purified water defined in USP terms?

Water obtained by ion exchange, reverse osmosis, ultrafiltration, distillation, or electrodialysis from potable water, with no added substances.

What is Water for Injection (WFI) and how is it produced?

Water purified by distillation and/or reverse osmosis, containing no added substances.

What distinguishes sterile water for injection from regular water for injection?

Sterile water for injection is sterilized and packaged in single-dose containers; specific solids and endotoxin limits apply.

Which disinfectants are commonly used in water treatment besides chlorine?

Chloramines (e.g., chloramines-T), dichloramine-T, halazone.

What is desalinization?

Removal of salts from seawater to produce fresh water, through evaporation/condensation, reverse osmosis, or electrodialysis.

What is water softening and what ions are removed?

Removal of calcium and magnesium ions to reduce hardness (temporary hardness from bicarbonates/carbonates; permanent hardness from sulfates).

What is the difference between temporary and permanent hardness?

Temporary hardness is from bicarbonates/carbonates of Ca/Mg; permanent hardness is from sulfates and other non-carbonate minerals.

What is a ‘red tide’?

Rapid growth of dinoflagellates that can turn water red and deplete nutrients/oxygen.

What is the littoral zone in a freshwater ecosystem?

The shoreline region near the water that is well-lighted and warmer, with phototrophic biota.

What are bio-indicators in water quality monitoring?

Large insects and animals whose presence or absence indicates water quality.

What does potable water mean?

Water of sufficient quality for drinking; treated to remove contaminants and stored properly.

What are compendial waters?

Purified waters that meet pharmacopoeia standards (e.g., purified water BP, water for injection BP).

What is turbidity and how is it measured?

Cloudiness of water due to suspended material; measured in NTU (Nephelometric Turbidity Units).

What does pH measure in water quality terms?

Potential hydrogen; measure of acidity/alkalinity.

What does electrical conductivity indicate in water testing?

Conductivity reflects the concentration of dissolved ions; higher conductivity means more dissolved salts.

Why are indicator organisms like E. coli used in water testing?

They indicate recent fecal pollution and potential presence of pathogens.

What is the McCrady’s probability table used for?

Estimating the most probable number (MPN) of coliforms per 100 mL from positive tube counts.

What is the principle of membrane filtration in water analysis?

Filtration of a large volume through a bacteria-proof membrane followed by culture on selective media.

What is DEFT and what is it used for?

Direct Epifluorescent Filter Technique; rapid detection and enumeration of microbes on membrane filters using acridine orange.

Name two non-culture methods for assessing microbial content.

Biosensors and direct measurement techniques (e.g., ATP bioluminescence, turbidity, DEFT).

What is the principle behind PCR in detecting microorganisms in pharmaceuticals?

Amplification of target DNA sequences to detect specific microbes; can be multiplexed (mPCR) for multiple targets.

What is LAL testing used for in pyrogen detection?

Limulus Amoebocyte Lysate (LAL) test; detects endotoxins from Gram-negative bacteria by gel formation.

What is the rabbit pyrogen test used for and what are its limitations?

In vivo test to detect pyrogens by monitoring temperature rise in rabbits; limitations include variability, ethical concerns, and insensitivity for some products.

What is Lipid A and why is it important in pyrogen discussions?

Lipid A is the endotoxin component of Gram-negative bacterial LPS and is primarily responsible for pyrogenic activity.

What are typical acceptable endotoxin limits for sterile injectable products?

Endotoxin limits depend on product; LAL is used to ensure pyrogen-free status; in many cases zero endotoxin activity is sought for sterile injectables.

How should water for injection be stored if not used immediately?

Storage at appropriate conditions (per notes, 4°C or 80°C in some contexts) to avoid microbial growth.

What is the role of turbidity as an indicator in water quality testing?

Turbidity indicates suspended material which often correlates with microbial presence and deteriorating water quality.

Name a protozoan that is resistant to chlorine and can pass through some filters.

Giardia lamblia (Giardia) and Cryptosporidium.

What is an ideal feature of an indicator organism regarding environmental hardship?

It should be present when pathogens are present, and resistant similarly to environmental stresses and disinfection.

What are some typical sample volumes used for presumptive testing in membrane filtration?

Volumes such as 10 mL, 1 mL, and 0.1 mL in different tubes (per the standard protocols).

What is the purpose of adding 0.1 mL of 3% sodium thiosulphate to bottles?

To neutralize residual chlorine in the sample.

What is the standard for total solids and conductivity in water for injection?

Total solids not exceeding about 10 mg/L and conductivity around 1 µS/cm.

What is the purpose of coagulation in water treatment?

Destabilize colloidal particles to allow them to collide and form larger flocs for removal.

Which ions are typically involved in temporary hardness?

Calcium and magnesium bicarbonates/carbonates.

Which ions are typically involved in permanent hardness?

Calcium and magnesium sulfates (and related sulfates).

Why is aeration used in large-scale water purification?

To oxidize dissolved compounds, remove odors, and convert iron/manganese to insoluble forms for settling.

What is the main purpose of describe the 'sedimentation' step?

Allow suspended particles to settle by gravity for clearer water.

What are the two main ways to assess microbial content non-culturally in pharma?

Biochemical indicators (e.g., ATP), and instrument-based rapid methods (biosensors, impedance, etc.).

What is the general purpose of bottle labeling and aseptic technique during sample collection?

To avoid contamination and ensure traceability of samples.

What are two common bacterial indicators of fecal contamination besides E. coli?

Streptococcus faecalis (Enterococcus) and Clostridium perfringens.