The 4 Medical Definitions Essential for

Epidemiologist & Microbiologist

Physician - Epidemiologist / Khaled M. AlmazAssistant lecturer, Community Medicine Department,

Aswan University hospital, Aswan, EgyptMaster Degree in Public Health , October 2011

Master Degree in Internal Medicine , April 2015

INFECTIONINFECTION is invasion and multiplication of microorganisms in a host, with an associated host response (e.g. fever, pain, edema, purulent drainage).• Infection may be local or generalized.• Infections may require antibiotic treatment.• Infection is preceded by colonization.

COLONIZATIONCOLONIZATION, whereby microorganisms are present in the host but do not invade or cause an associated host response, is distinct from infection. No treatment is needed.

The 2 Medical Definitions Essential for

Epidemiologist

Main Members in the IC teamالفريق أعضاء

in Public Health (Epidemiology) Infectious Diseases Physician (if available).

Occupational Health Physician (if available).

Chief executive, or hospital administrator or his/her nominated

representative.

- Epidemiology (for Communicable infectious – for Non-Communicable / Non-Infectious) endemic & epidemic diseases…

  معدية الغير االمراض و المعدية االمراض من للوقاية الوبائيات علم- Health care waste managements…

 المستشفيات مثل الطبية الخدمية المراكز نفايات من التخلص- Infection control administration & training …

 العدوي مكافحة ادارة- Investigation of outbreak (Acute Surveillance)…

 المعدية لالمراض وبائية كوارث حدوث عند االجراءات- Surveillance (in Egypt >> notification of the 27th infectious diseases ; class A / B / C )…

القصوي االهمية ذات المعدية aلالمراض انتشار و حدوث معدل عن دورية بصفة التبليغQuality Assurance of Medical Practice Administration

الصحية الرعاية خدمات و الطبية االكلينيكية الممارسة في الجودة

Difference between Eradication, EliminationYou now know that not all diseases can be eradicated. But, that doesn't mean they can't all be

managed to a certain extent. Most diseases can be eradicated, eliminated or controlled. Here's how to differentiate them.

Eradication : is the complete annihilation of a disease due to methodical efforts. True eradication usually involves eliminating the microbe itself or completely preventing its occurrence in nature.

Elimination : is the process of stopping the spread of a disease in a country or continent or other restricted area, such as an island. It's also possible to stop people from contracting a disease while the microorganism remains alive in nature, such as with neonatal tetanus.

Control : is a method for reducing the frequency of a disease, but has to be an ongoing effort.

Classification of CarrierHealthy carrier : has organism but not suffer from disease , inhabitant

by get infected from polluted environment as water supply and food .Convalescent carrier : after cure and recover from infectionTransient carrier : for few daysTemporary carrier : less than 6 months , few weeksChronic carrier : more than 6 months , few yearsContact carrier : acquire organism from patient caseParadoxical carrier : acquire organism from another carrier

• Incubatory carrier : the case is infectious in some disease for period of time in the incubation period

According to foci of infection : upper respiratory , GIT , Urinary tract carriers.According to exit of infection : feces , urine , respiratory.

Common Mistakes regarding this topic: ARIs : Acute Respiratory InfectionsMRSA: Methicillin Resistant Staphylococcus Aureus Infection.SARI : Sub-acute respiratory illness.SARS : Severe acute respiratory syndrome.-----------------------MERS: Middle East Respiratory Syndrome.

Most common in Middle East: Corona Most common Globally Pandemic: Swine flu & Avian Flu

So: MERS is specified recently to corona and this is called: MERS-cov.

• Meningitis: mentioned before.

Neurological Infections of high medical importance

The following 5 neurological infections are possible in Hospital Acquired Infections ** But the least common is: Myelitis if infectious causes. Meningitis: (cause: Bacteria – Virus). Encephalitis: (letter C: spelling is: C or K) : affect brain parenchyma Meningio-encephalitis : Causes: bacteria – virus. Encephalomyelitis Myelitis : As: Transverse Myelitis (infectious cause). ========================= • Others: Fever with decreased loss of consciousness. Meningism It is: Aseptic meningitis (causes: irradiation – chemical – rabies).

Recent HCV ttt in 2016 ,, Prof. Gamal EsmatMember of WHO Strategic Committee for Viral Hepatitis

OLYSIO® (simeprevir)

SOVALDI® (sofosbuvir)

HARVONI® (ledipasvir 90 mg/sofosbuvir 400 mg)

TTT outcomes of viral Infection :

HCV : curable and treatable (live in blood waste out of the human body for 3 days).

HBV : clean virus (live in blood waste out of the human body for 3 months).

HIV \ AIDS : not curable (live in blood waste out of the human body for 3 hours).

Acute Infectious Emergency

Toxaemia : toxins of bacteria in blood vessels

Bacteraemia : small number of bacteria

Septicaemia : large number of bacteria with its toxins

Pyemia : septic emboli in blood vessels cause : Abscess – pus formation

Saprymia : Gangrene : metabolic toxins result from action of saprophytic bacteria

Acute Fever presentation (Emergency Hot Weather Diseases)

Heat Stroke: coma, convulsions and delirium.

Sun Stroke.

Heat Exhaustion: water and salt deficiency.

Heat Cramps: sudden onset of painful spastic cramps of the skeletal muscles most actively used during work.

Heat rash (miliaria rubra): acute inflammatory disorder of the sweat glands.

Skin burns: Result from exposure of skin to excessive heat radiation or hot air.

Malaria Eradication program• Destroy mosquito vector• Mass case finding ( support eradication )• Chemoprophylaxis ( support eradication )• Health education ( support eradication )• Follow up of work by maintenance of eradication• WHO recommendation

Steps of Malaria Eradication

Management

Intervention

Vaccination

The 2 medical Definitions Essential for

Microbiologist

Main Members in the IC teamاaلفريق أعضاء

(in Microbiology) ICD or hospital microbiologist (chairperson).

• Because Hospital Microbiologist (Microbiology & Immunology Department in Medical School >> know the Heat & chemical treatment that used in Sterilization or in Disinfection…

• While Forensic Medicine & Toxicology Department in Medical School >> make investigations of Toxins (biological Toxins & Chemical Toxins)

- Health care waste managements…

  مثل الطبية الخدمية المراكز نفايات من التخلصالمستشفيات

- Infection control administration & Practical rules & training …

 العدوي مكافحة ادارة

Prevention & Control Health Care Acquired ( Nosocomial ) Infection

One of the guides for prevention is :Elimination of contamination by equipment:CleaningDisinfection : reduces the harmful organisms to a level where the risk of

infection is considered so small as to be acceptable. Sterilization : destroys all living organisms ; either in the vegetative or spore

state.IsolationAntisepsis

Cleaning

Differences between Anti-Septic & Disinfectant

Anti-Septic Disinfectants

1. All antiseptics are disinfectants. All disinfectants are not antiseptics.

2. It can be apply on the live tissues.

It can be applied on inanimate object.

3. Eg:- Skin or mucous membrane. Eg:- Surface, lab working tables, floor or material.

DisinfectionDisinfection reduces the population of harmful organisms to a level where the risk of infection is considered so small as to be acceptable. Disinfection just cleans.

Disinfectants are antimicrobial agents that are applied to non-living objects to destroy microorganisms, the process of which is known as disinfection.

Antisepsis & Anti-SepticAntisepsis: Prevention of infection by inhibiting or arresting the growth and multiplication of germs (infectious agents). Antisepsis implies scrupulously clean and free of all living microorganisms.Antisepsis: Prevention of infection by inhibiting or arresting the growth and multiplication of germs (infectious agents). Antisepsis implies scrupulously clean and free of all living microorganisms. Reduction of or inhibition of microbes found on living tissue.Anti-Septics : Chemical disinfectants which can be safely applied to

the skin or mucous membrane and are used to prevent infection by inhibiting the growth of bacteria are called antiseptics.

Isolation

Isolation Designed to Prevent Transmission of Microorganisms by common routes in Hospitals.

Sterilization ( Sterilisation )Sterilization refers to any process that effectively kills or eliminates transmissible agents (such as fungi, bacteria, viruses, prions , spore forms etc.) from a surface, equipment, foods, medications, or biological culture medium. Sterilization can be achieved through application of heat, chemicals, irradiation, high pressure or filtration.Sterilization destroys all organisms. Sterilization destroys all living organisms (either in the vegetative or spore state ).. Sterilization of all reusable equipment such as : ventilator, humidifier , any device that come in contact with the respiratory tract.

Hand Washing

How to sneeze to prevent disease!

WHO Recommended Hand Hygiene Technique

• Hand rub/hand wash• 15-20 seconds

Where is the dirt?

Number of bacteria per square centimeter: Scalp-1,000,000 Forearm-10,000 Arm pit-500,000 Abdomen-40,000 Hands-40,000 to 500,000

Diagnosis & Guideline about how to deal with HAIs

in Laboratory &

Elimination of contamination

METHODS OF STERILISATION & DISINFECTION The following methods are commonly used in the microbiology laboratory and hospital.

(I) PHYSICAL METHODSunlight, Drying,Dry heat: Red heat, Flaming, Incineration, Hot air oven.Moist heat: Pasteurization, Boiling, Autoclave (Steam under pressure).Filtration and Radiation etc.

(II) CHEMICAL METHOD

Alcohols, Aldehydes, Halogens (Iodine, Chlorine etc), Phenols, Gases and Surface - active agents (soap, detergent) etc.

HOT AIR OVENThis is the most widely used method of Sterilization by Dry heat.

A holding period of 160°C for one hour is used to sterilize glassware, forceps, all-glass syringes, swabs etc.

Glassware should be perfectly dry before being placed in the oven. Test tubes and flasks should be wrapped in paper.

The material should arranged so as to allow free circulation of air in between the objects.

Hot air oven

It should not be overloaded. It must be fitted with a fan to ensure even distribution of air.The oven is usually heated by electricity with heating

elements in the wall of the chamber. The oven must be allowed to cool slowly for about two hours

before the door is opened, since the glassware may crack due to sudden or uneven cooling.

HOT AIR OVEN

STERILIZATION BY MOIST HEAT

Moist Heat is divided into 3 methods;

1) Temperature bellow 100°C Eg: Pasteurisation of milk.

2) Temperature at 100°C Eg: Boiling of water.

3) Temperature above 100°C (Steam under pressure)

Eg: Autoclave.

AUTOCLAVEIn its simplest form, the laboratory autoclave consists of a vertical or

horizontal cylinder of gunmetal or stainless steel.

The lid or door is made airtight.

The autoclave has on its lid or upper side a discharge tap for air and a safety valve that can be set to blow off at any desired pressure.

Heating is by gas or electricity.

Sufficient water is put in the cylinder, the material to be sterilized is placed on the tray and the autoclave is heated.

The lid is screwed tight.

AutoclaveThe steam pressure rises inside and when it reaches the desired set level, the safety

valve opens and the excess steam escapes.

From this point, the holding period is calculated. The holding period is 121° C at 15 pound pressure for 15 minutes.

When the holding period is over, the heater is turned off and the autoclave allowed to cool till the pressure inside is equal to the atmospheric pressure.

The discharge tap is opened slowly and air is let into the autoclave.

The domestic pressure cooker serves as a miniature autoclave and may be used for sterilizing small articles in clinics.

AUTOCLAVE

FILTRATIONMembrane filters are widely used which is made of cellulose esters or

other polymers. Their average pore diameters (APD) is 0.22 mm size.

Filtration helps to remove bacteria from liquids such as sera and solutions of sugars or antibiotics used for preparation of culture media.

Membrane filters

RADIATIONTwo types of radiation are used for Sterilization – Nonionizing &

Ionizing. IONISING RADIATION Infrared and Ultraviolet

rays are of the nonionizing low energy type.

Applications:-

Clean surfaces like inoculation hoods, microbiology & other laboratories, hospital wards and operation theatres etc.

X-rays, Gamma rays & Cosmic rays are highly lethal to all cells including bacteria.

They have very high penetrative power. They damage DNA by various mechanisms.

Applications:-Commercial plants use gamma radiation for sterilization of disposable items such as plastics syringes, swabs & animal feeds etc.

NON-IONISING RADIATION

(II) CHEMICAL AGENTSSeveral chemical agents are used as antiseptics and disinfectants used in the

microbiology laboratory and hospital. However little is known about the mechanism of action of many of these agents.

An ideal antiseptic or disinfectant should be:-Have a wide spectrum of activity and must be effective against all microorganisms,

that is, bacteria including spores, viruses, protozoa and fungi;

Have speedy action; Have high penetrating power; Be stable.

Not corrode metals; Not cause local irritation or sensitization;

Not interfere with healing; Not be toxic if absorbed into circulation;

Be cheap and easily available; Be safe and easy to use.

ALCOHOLSEthyl alcohol (ethanol), Isopropyl alcohol and Methyl alcohol are the most frequently

used.They are used as Disinfectants & antiseptics. Their mode of action is denaturing

bacterial proteins. Methyl alcohol is effective against fungal spores and is used for treating cabinets and

incubators affected by them.

ALDEHYDES Formaldehyde is active against the amino group in protein molecule. It is used to preserve anatomical specimens.Surfaces which have disinfected by this agent may give off an irritant vapour for some

time after disinfection.

HALOGENSIODINE

Iodine is widely used as a skin disinfectant (antiseptic).It is active against bacteria, fungi and viruses etc.Ex.: Betadine.

CHLORINEChlorine is used as disinfectants in microbiology laboratories, hospital,

water supplies & swimming pools etc.Chlorine is commonly used as hypochlorites. Chlorine and hypochlorites are markedly bactericidal. They have a wide spectrum of action against viruses.

PHENOL Phenol (carbolic acid) is a powerful and good general disinfectants. Phenol is widely used as disinfectants for various purposes in

microbiology laboratories & hospitals. Lysol and cresol are active against a wide range of organisms.

GASESFORMALDEHYDE GAS

This is widely employed for fumigation of operation theatres and other rooms. After sealing the windows and other outlets, formaldehyde gas is generated and left unopened for 48 hours.

Commonly used Chemical Agents in Microbiology laboratory and Hospital

ALCOHOL FORMALDEHYDE

IODINE PHENOL CHLORINE

DETERGENTSLYSOL

IMPORTANCE OF QUALITY CONTROL(Quality Assurance of Medical Practice

Administration)

Quality control is defined as a process to identify errors in a procedure.

This is a reactive process where errors have already occurred.

Quality control is a measure how well the measurement system reproduces the same result over time and under varying

operating conditions.

Importance of Quality ControlWithout quality control, errors in a clinical setting can lead to patient mis-

diagnosis, delays in treatment or administration of the wrong treatment and increased costs associated with retesting.

Quality assurance schemes are vital both in a preclinical, clinical settings and in clinical trials.

Quality assurance schemes are essentially procedures designed to ensure that a study being performed is compliant and that data being generated is accurate.

This ensures the reliability of test results, to give the best patient care.

Importance of Quality ControlExample of Quality control:-

Sterilization control for Hot air oven• The spores of Clostridium tetani are used as test of dry heat efficiency.

• Paper strips impregnated with spores are placed in envelopes and inserted into suitable packs.

• After sterilization, the strips are removed and inoculated into thioglycollate or cooked meat media and incubated for sterility test under strict anaerobic conditions for five days at 37°C. If there is no growth in the culture media, the hot air oven works properly.

Hospital Acquired InfectionsHAIs

Nosocomial InfectionsHealth care Acquired Infections

Distribution of Pathogens Causing HAIs

Type of pathogens N=841 (%)

Klebsiella spp. 175 20.8

Acinetobacter spp. 141 16.8

Pseudomonas spp. 94 11.2

E.coli 70 8.3

S.aureus 68 8.1

CONS 88 10.5

Enterococcus spp. 19 2.3Candida albicans 100 11.9

Others 86 10.1

Healthcare-associated InfectionsExcess length of stay

Type of infection Excess hospital stay (days) Bloodstream infection 7.4 Surgical site infection 7.3 Pneumonia 5.9 Urinary tract infection 1.0 Others 4.8

MRSA = Methicillin-resistant Staphylococcus aureus infection

Candida Albicans

CONS = Coagulase-negative staphylococcal infections

VRSE = vancomycin resistant enterococci