Microbiology, Lecture 16

8/7/2019 Microbiology, Lecture 16

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Today well talk about Nosocomial Infections and Healthcare Epidemiology, chapter 12 from the text book

Lets begin with some definitions:

Healthcare Epidemiology is the study of the occurrence, of determinants and distribution of health and disease within healthcarefacilities, and includes any activities designed to improve patient careoutcomes.

The primary focus of healthcare epidemiology is on infection control andthe prevention of healthcare- associated infections

So generally speaking, people can acquire two types of infections:

1- There are diseases or infections that people acquire outside thehealthcare settings and these are called community-acquired infectionsand these arent the focused of these talk.

2- You have infections that you can acquire during your stay at thehealth facilities such as a hospital or a clinic and these are calledhealthcare-associated infections and another common name for them isNosocomial Infections.

Nosocomial Infections are very serious problem, for example, in theUnited States -which obviously has high standards with health care- evenin that country, out of 40 million people who end up being hospitalized,2 million people end up acquiring an infection during the hospital stayand many of these people end up with serious diseases and mightactually died from these type of infections.

So there are certain strains of bacteria more commonly associated withnosocomial infections and I want you to memorize these names. So wehave bacteria that are Gram-positive and Gram-negative that cause thesetypes of infections and

- well begin with the Gram-positive ones We have Staphylococcusaureus, coagulase-negative staphylococci, and Enterococcus spp.

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- For the Gram-negative, we have Escherichia coli, Pseudomonasaeruginosa, Enterobacter spp., and Klebsiella spp.

So these bacteria can come from variety of sources, sometimes they can

be taken or they cause infections because their part of the normal flora of the patient himself, so if you have a surgical wound, that surgical woundcan be contaminated from the patients skin. Sometimes these bacteriacan be derived from health care workers and from surfaces in the lab.And a major problem of these infections is that most of the bacteria thatcause the infections are drug-resistant bacteria, so that they only causeinfections in immune compromised people but also they are very hard totreat with the regular or usual types of anti-microbial agents.

The diseases caused by these bacteria in a descending order of frequency, most commonly we have:

1- Urinary tract infections

2- Surgical site infections

3- Lower respiratory infections (primarily pneumonia)

4- Finally, we have Bloodstream infections or Septicemia (least

common)Also we have other causes of disease in the hospital sitting; an exampleis Clostridium difficile- associated disease which usually appears if youtake course of antimicrobial agents for many periods of time.

Patients at risk of developing human or health care associatedinfections :

Basically any person who undergoes invasive procedures, invasivesurgical procedures or catheterization or people with Immunesuppressions, these people are more like to develop or acquire hospital-acquired infections, for example:

1- Elderly patients

2- Women in labor and delivery2


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3- Premature infants and newborns

4- Surgical and burn patients

5- Diabetic and cancer patients

6- Patients receiving treatment with steroids, anticancer drugs, antlymphocyte serum, and radiation

7- Immunosuppressed patients in general

8- Patients who are paralyzed or are undergoing renal dialysis or catheterization

So we have lots of factors to acquiring the health care associated

infections but the three most common factors are:1- We have increasing numbers of drug-resistant pathogens that areemerging in the community

2- Failure of healthcare professionals to follow infection controlguidelines, for example: they might not be washing their hands properlyor they might not be washing their hands frequently between patients, soyou cant handle a patient with a severe infection then go and handle

another person without washing your hands.And finally more people are surviving these days with immune-suppressed status; so people now with cancer can survive for a long time,so these people can acquire more easily the nosocomial infections.

Then we have additional factors that play a role and these basically arecommon sense:

- Overcrowding of hospitals and shortages of healthcare staff.

- The indiscriminate use of antimicrobial agents and the false sense of security about antimicrobial agents; so people now keep saying if yougo to any small clinic at any town and you tell them you have streptthroat they will give you amoxicylin ,without testing the bacteria so nowthey are giving antimicrobial agents without doing the proper steps and

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this is generating lots of bacteria that are resistant to the regular antimicrobial agents.

- Lengthy and more complicated types of surgery; the more invasive and

the more prolonged the procedure is, the more chance that you mightacquire an infection from that procedure.

- Increased use of less-highly trained healthcare workers.

- Increased use of anti-inflammatory and immunosuppressant agents.

- Overuse and improper use of indwelling devices.

*How can we prevent nosocomial infections?

Each hospital or each clinic needs to have certain established guidelinesand rules to prevent infections, we call these Infection controlguidelines , and one of the major steps or things that you need to applyduring an infection control plan is hand washing. Hand washing alonecan prevent a lot of the nosocomial infections, so by hand washing youreduce the risk of transmitting the disease from one patient to another or even transmitting the disease or the pathogen from one anatomical site of the patient to another site of the patient.

Finally we have another means of control and again these most of themare more common sense so using proper disinfection and sterilizationtechniques,, air filtration for people for example transmitting air borninfections,, the use of ultraviolet lights to sterilize large surfaces( floors,sealing) , isolation of especially infectious patients; so people withSwine flu for example you need to quarnty these people in a certain

private rooms,, wearing gloves, masks, and gowns whenever appropriate.

*Infection control :

Definition of infection control: it is the numerous measures taken to prevent infections from occurring in healthcare settings.

One of the major techniques that are required for infection control issomething called Asepsis , which means without infection. So aseptic

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techniques are techniques that prevent infection from happening and wehave two types of asepsis: we have something called Medical asepsisalso known as clean technique and we have something called surgicalasepsis or sterile technique.

Medical asepsis are basically precautionary measures necessary to prevent direct transfer of pathogens from one person to another or indirect transfer of pathogens through the air or on the instruments,

bedding equipment, and other inanimate objects.

So with medical asepsis you are trying to reduce the risk of transmissionof pathogens by reducing the number of bacteria and reducing the waysthat these bacteria can spread to people. And more likely or mostly with

medical asepsis you are preventing the transfer of pathogenic bacteria.This is in contrast to surgical asepsis or sterile technique in which you

try to observe or to create sterile environment. So you are preventing thetransfer of all types of bacteria regardless of whether they are pathogenicor nonpathogenic.

So obviously surgical asepsis is required for surgery rooms, when youare doing catheterization or when you are taking samples of blood or

trying to take a sample of fluid through lumber puncture, so during allthese techniques you have to create a sterile environment either byrubbing the skin with alcohol or by using types of disinfectants or lightto sterilize the whole environment.

Infection control involves two types of precautions:

First we have what is called standard precautions ; these are universal precautions that need to be applied regardless of the patient you aredealing with or regardless of the department, so these are global rulesthat you need to follow, for example wearing of gloves , masks, eye

protection, and gowns, safe injection practices all these you havealways to do them regardless of the person you are dealing with whether or not he has aids or whether or not he has for example the common coldand usually each facility should have a sticker that shows you the varioustypes or standard precautions that are established in that facility, for

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example for all people you need to do the proper hand washing and thissticker ( refer to slide 15 ) will tell you how to do the proper handwashing, when to wear gloves, when to wear masks and eye protection,when to wear gowns, patient-care equipment for example it is not wise touse one blood pressure machine for a whole Work so you cant keepusing it for patient after patient after patient and the best thing to do is toMedicate one blood pressure machine to each room so only that patientwill use that machine and so on.

Environmental control: you need to observe certain ways how to clean beds, tables and so on.

Occupational health and blood borne pathogens; there are certain

guidelines how to eliminate and discard sharps such as needles, how todispose contaminated material and finally there are guidelines for howand when to place people in private rooms .

So here are example of ways or we can use prevent infection so youmight to wear a sterile gown, mask, and gloves.

Gloves in general have a special way to take or remove from your handso lets say you have used it with a patient and now obviously

contaminated with skin normal flora or bacteria taken from a surgicalsite with infection or blood so you dont want to contaminate your handwith these bacteria so the way to take them out is using your right handto grape the edge of the other glove and take out and then from the insideof the glove you try to grape it and then you take it out without touchingyour hand.

Transmission-Based Precautions

So they are used are used for patients who are known or suspected to beinfected or colonized with highly transmissible or epidemiologicallyimportant pathogens, for example someone with Evola or Swine flu youobviously want to guarantee on these people and make that you donttransmit the diseases to other people , so these precautions are divided tothree categories :

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1. Contact Precautions

2. Droplet Precautions : basically are utilized so when we have someonecoughing (for particles > 5 m in diameter)

3. Airborne Precautions : are for people who sneeze and create verysmall particle witch diameter is less than 5 m.

The particle that are more than 5 m cannot spread or staminate for largedistances usually 1 meter, whereas the other particles witch smaller insize ( less 5 meters ) can spread for large distance ;so these two typeshave different ways of precautions .

Contact precautions again these are common sense so whenever

possible you have to place the patient in private room, if you dont havea private room for every patient you have to group patients with similar disease in one sterile room, whenever you have to deal with patient youobviously have to wear gloves and discard these gloves from patient to

patient, wash your hands before and after dealing with these patients.Wear gown if necessary, limit transport patient from location to location,and finally try to keep one medical instrument for each patient if

possible, so by doing these things we can prevent direct transmittion

from surface to surface or from body surface to body surface and youcan also prevent the indirect transmition pathogen through contaminatedobject to another patient.

Almost there is a lot of bacteria and microorganism can transmitteddirectly through contact and this is just a small list of such pathogens andI dont want you to memorize these but you can read them for your owninterest ( ya3ni btetsallo feehom b aw8at l fara3 :P ) .

Droplet precaution :Are for particle that larger than 5 m witch cannotspread for large distance and usually for 1 meter and then there are not a

problem .

So a health care professionals needs to wear a mass around these patientsand if you transporting the patient outside his/her room try or you should

basically put a mass around the patient himself because if he coughs

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outside the room there is a little chance to transmit the pathogen to other people . And again theres some examples of such pathogens and skipthem.

And finally airborne precaution : So these are for particles which havesize less than 5 m so if you sneeze you can generate these particles andthese can be carried in air conditioning unit, in rooms, in large hallwaysfor large distances, so you have to use special type of masks for thesecalled an N95 respirator and for the patient himself if you transportinghim outside a typical surgical mask can be enough.

And again we have some examples of some pathogens that you need toobserve these types precautions (skip the slide) and if you look to these

pathogens you will notice that some of them need contact precaution,some airborne precaution, and some it need all of the precautions, so itsnot exclusive; we can have contact and airborne precaution for one

bacteria and virus.

SARS is caused by a virus its called corona viruses and most coronaviruses caused upper tract infection and there are no other coronaviruses cause lower tract infection except for SARS and I think themortality rate for the SARS = 10% so its fatal .

Here is an example for the N95 respirator. We have something calledAirborne Infection Isolation Room or ( AIIR) , so lets say someone hasSARS , SWINE flu and you want to protect people from being affectedwith these pathogens so what you do is replace this person in a small

private room and the goal of this room is to prevent the pathogens fromgoing outside the room , and basically this room is equipped with ventand this vent respect has a very tight filter attached to it , this filter called a keeper filter or highly efficiency particular filter so this filter canisolate all type of bacteria , so basically first station in this room you setthe air outside the room and all the air will pass through the filter so allthe air leaving the room will be sterile and basically when you draw theair out you leave negative pressure inside the room so the negative

pressure will lead to the air in the hallway to enter the room , so basicallywhen we do this no air will exit the room and so you keep the people

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outside the room protected from this pathogens, and the air exit from theroom will be sterile because it pass through the filter . So we will do thisfor people infected with highly infection pathogens again such as SARS,SWINE flu and so on.

The opposite scenario happens with something called the protectiveenvironment , so some people are severe immune-compromised andsusceptible to many pathogens even components of the normal flora,example of that people with leukemia, transplant or immuno-suppressed

patients, patients receiving radiation treatment, leukopenic patients, premature infants. So these people are susceptible to most bacteria andmost viruses and can be easily infected , so one way to protect them is to

place them in a private room but now you using event to put air insidethe room so all air entering the room is sterile and this will create a

positive pressure inside the room so air will exit the room and will notenter the room from the hallway , so this patient will never experienceany pathogen from outside , all the air he/she exposed to will be sterileair .

Handling Fomites

So when you working with healthcare professions you will generate a lotof inanimate wastes , for examples gowns, cotton , wooden sterile ,surgical instruments, needle, and gloves , all of these can becontaminated with pathogens , so you have to handle these fomites withspecial guidelines , so for example its preferable to use something thatsdisposable than its reusable, Disinfect or sterilize equipment soon after use, Use individual equipment for each patient, Use disposablethermometers or thermometer covers for each patient .

Needles and sharp materials have special guidelines for the disposal, soif you have broken glass you have to place the broken glass in a specialcontainer, if you have needle you have to place them in especial puncture

proof container, and usually each hospital should have guidelines how tohandle the sharps and other material.

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Infection Control Committees and Infection Control Professionals

So each hospital and each institution should have a group of peoplededicated to monitor and establishing Infection Control guidelines and

this is called the infection control committee or (ICC) ; so ideally youshould have members in this committee that represent most departmentof the hospital and health care facility , so you have person to representincluding medical and surgical services, pathology, nursing, hospitaladministration, risk management, pharmacy, housekeeping, foodservices, and central supply , but in addition to these the chairperson or the president of this committee need to have high knowledgeable aboutinfectious diseases so you need to have an epidemiologist or infectiousdisease specialist, an infection control nurse, or a microbiologist as achairperson to that committee .

Role of the Clinical Microbiology Laboratory (CML) in HospitalEpidemiology and Infection control

So obviously the microbiological labs is always testing sample from patient and try to see what type of organism are present so lets assumethat the lab is processing sample from a burn wound and he start toobserve many infection caused by Seminomas Arigona bacteria, findingthese high frequency of infection triggers a life that could be potentiallycoming from a local source and not necessary come from theenvironment so the lab needs to tell the infection control committee thatthey were observing higher than normal infections of this type of organism so the infection control committee will implement certainguidelines to investigate if theres actually contamination with this

bacteria or not ;then they will start to doing random or methodologicalscreening for particular ward, they start to taking sample from pinch top ,

from nursing hands , doctors hands , to know where is the bacteria camefrom.

All healthcare workers must fully comprehend the problem of HAIs,must be completely knowledgeable about infection control practices, andmust personally do everything in their power to prevent HAIs fromoccurring. This the course are very sever and can either increase stay of

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the patient in the hospital or killing the patient , and HAIs can be avoidedthrough proper education and disciplined compliance with infectioncontrol practices.

Sorry for any mistake, we did our best.

Done By Haneen al-kawamleh , Walaa khdour .

Special hi goes to Eman tawalbeh and Difaf khwaileh

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Microbiology, Lecture 16