Pharmaceutical Microbiology (MIC 202)

Intended learning Outcomes of Course (ILO's): a)Knowledge and Understanding: By the end of the course the student should be able to: The basic principles of GLP guidelines for microbiological applications in pharmacy practice. a2- The basic principles of antimicrobial chemotherapeutic agents, classification,their mechanisms of action,indications, side effects,antibiotic policy and microbialresistance. a3- The basic principles of Non- antibiotic agents and preservatives and their pharmaceutical and other applications. a4-The definition of the basic principles of sterilization. a5- The identification of different methods of sterilization of pharmaceutical products. 2

b- Professional and practical skills: On successful completion of the course, the student should be able to: b1- Apply GLP guidelines for microbiological applications in pharmacy practice. b2-Apply the appropriate techniques for qualitative and quantitative assessment of microbial growth and antimicrobial agents. b3- Assess the activity of diverse antimicrobial agents in controlling microbial growth and using a suitable laboratory tests to detect MIC. b4- Apply some sterilization methods.

c- Intellectual skills: By the end of the course the student should be able to: c1- Select suitable method for isolation of microorganisms. c2- Select the most suitable antimicrobial agents acting against different microorganisms according to the collected data and recognize their mode of action. c3- Identify the microorganisms by correlating the microbial characteristics and metabolic process results of biochemical tests. c4-Suggest suitable sterilization methods to be used for sterilization of different materials according to their applications.

d- General and transferable skills: On successful completion of the course, the student should be able to: d1-Use oral communication to effectively transmit ideas and conclusions to a scientific audience. d2- Demonstrate interpersonal skills and team working ability by the successful completion of collaborative learn assignment and videos. d3-Present research finding in oral and written from using arrange of appropriate software (e.g., power point, word, excel and data base). d4- Implement calculation for MIC test.

Sterilization

Sterilization The process of freeing of an article from all living organisms including spores, either through killing or removing. Sterilization is required in the following fields: 1-Microbiology: Media - containers - 3-Pharmacy: Injectable - ophthalmic 2-Biotechnology: Fermentation media & vessels. 4-Surgery: dressing, sutures &equipment. 5-Medical devices: syringes, gloves, cannulas Methods used in sterilization are either : 6-Computer and space industry. A) Physical (does not remain in the final preparation) 1-Dry and moist heat 2-Radiation 3-Filtration B)Chemical (remain in the final preparation except for gases( 1-Ethylene oxide 2-Heating with bactericide

 Expressions of resistance:  Thermal death time (extinction time): Shortest time required to kill all M.O. in a suspension at certain temp Thermal death point: lowest temp required to kill all M.O in suspension with in certain time(usually10min)  Inactivation factor (IF): It is a measure of the destructive power of a sterilization process  IF = a/b  a = initial number of M.O. (bioburden(  b = number of M.O. after sterilization treatment 

 Factors affecting heat sterilization: a)Time & temp of exposure. d)Nature of the article to be sterilized.  Heat transfer: b)No. of M.O. (bioburden(. c)Type of M.O Direct: e.g. incineration only used for highly infective materials e.g. loop. Indirect either through: 1-Radiation: using infrared (I.R( 2-Convection: through air, water or oil, by currents of heat. 3-Conduction: usually through metals (slow(  Mode of action of heat sterilization:  Moist heat: death is through protein and nucleic acid denaturation.  Dry heat : death is due to slow protein denaturation, through oxidation of certain groups in the protein.

 Dry Heat Sterilization Application: Thermostable substances e.g. glass (vials, flasks, Petri dishes), metals (forceps), anhydrous oils (paraffin, wax) powders (talc) porcelain, silicon rubber. Not suitable for water containing substances, thermolabile substances, all fibers (dressing, plastics(.  Conditions: B.P =150°C for 60 min for medicaments &160°C for 60 min for glass.  Heating at lower temp for prolonged time is more damaging than rapid heating at higher temp .  Methods of dry heat sterilization  1- Incineration: Used for terminal disinfection of highly infectious materials e.g. loops, surgical tools in emergency. Swabbing with alcohol and flaming is preferred to direct incineration. 

 2) Hot air oven (sterilizer): Stainless steel double walled insulated chamber with perforated shelves. Heated electrically by coils. A fan is placed in the back (continuous circulation of heat &ensure uniformity of temp(   Precautions:  Items should not be placed compact to allow circulation of air.  Items, which resist heat transfer (talc powder), should be placed in shallow layers.  Items which allow convection of heat (oils) could be sterilized in bulk.  Articles to be sterilized should be introduced into the oven at room temp and after sterilization. 

 3) Infrared tunnel (I.R.): (wave length 700-950 nm) lamps (for heating. I.R). It is a type of continuous sterilization, used mainly for empty ampoules or vials.  4) Conductive oven: Electrically heated metal block with grooves for surgical tools(expensive &low efficiency).  Advantages of dry heat:  less damaging to metals and glass.  Articles remain dry.  used for substances damaged by moisture e.g. powders and oils.

 Methods for moist heat sterilization: I) At normal pressure (at or below 100°C):  a) Pasteurization: not used in sterilization: It used to kill milk pathogens such as Mycobacterium tuberculosis. It improves & maintain the nutritive quality of milk.  This a type of disinfection, carried out in 2 ways:  Holding process: heating at 62°C for 30 min then cooling to 7°C.  Flash process: heating at 72°C for 15 sec then rapid cooling to 4°C.  b) Boiling in water: not used in sterilization.  Used in emergency (kills most pathogenic bacteria in less than 10 min ,but not spores or hepatitis B virus(  c) Steaming: not used in sterilization: Spores require 26 hrs. to be killed.

 d) Tyndallization: not used in pharmaceutical and surgical sterilization. Consists of moist heating the article at 100°C for 30 min on three successive days and incubation at 37°C in between. First heat treatment kill vegetative cells and during incubation spores germinates which are in turn are killed by the second and third heat treatment.  e) Inspissation: As tyndallization but temp is kept at 85°C only. Used for sterilization of egg media e.g. Lowenstein Jensen and Loffler's media.  f) Sterilization of vaccines: By heating at a temp which just kill the M.O. but do not affect its antigenicity. Cholera vaccine is sterilized by heating at 56°C for one hr.  g) Sterilization by heating with bactericide:  Consists of heating at 100°C for 30 min. in the presence of a bactericide, which should be non toxic, non volatile, stable, and compatible with the ingredients, The bactericide used for e.g:  phenyl mercuric nitrate (0.002%) in eye drops.

 Disadvantages of this method: Not used intravenous injections with volume exceeding 15 ml.  Not used for oily injections as the oil solubilize the bactericide.  The bactericide remains in the final preparation.

Prepared by Dr. Lina Jamil