Infection Process and Infection Control
Throughout history man has faced the spread of infection, pondering its causes and how to treat it or prevent it. Infections have been known to affect major segments of the population, as did the plague in the Middle Ages. Although important advances have been made in understanding and treating infection, the threat of infection looms as large as it ever has. Newer enemies in the battle of infection emerge such as HIV and hepatitis C virus (HCV). Once-conquered enemies become resistant to treatment, as it the case of Mycobacterium tuberculosis and methicillin-resistant Staphylococcus aureus. Healthcare personnel typically encounter numerous patients on a daily basis, many of whom may be harboring these or other agents of infection. Measures to prevent the spread of infection must be taken in the course of treating all patients.
Infection Process and Infection Control
Bruno Mars - Locked Out Of Heaven [OFFICIAL VIDEO]
Video Clips. Duration : 3.92 Mins.
Bruno Mars - Locked Out Of Heaven [OFFICIAL VIDEO]
WATCH THE SATURDAY NIGHT LIVE RECAP HERE: bit.ly Download the single now on iTunes: smarturl.it Pre-order the new album 'Unorthodox Jukebox' (US only) atlr.ec German fans watch the video here: bit.ly Directed by Cameron Duddy & Bruno Mars brunomars.com http facebook.com © 2012 WMG.
Bruno Mars - Locked Out Of Heaven [OFFICIAL VIDEO]
Bruno Mars - Locked Out Of Heaven [OFFICIAL VIDEO]
Bruno Mars - Locked Out Of Heaven [OFFICIAL VIDEO]
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The Best Computer For Graphic Design
Since Desktop Publishing (DTP) came out in the eighties, graphic designers have been utilizing computer technology. This has pushed all graphic designers to become competent with computer hardware at the very least.
The Best Computer For Graphic Design
Nicki Minaj - Va Va Voom (Explicit)
Tube. Duration : 3.35 Mins.
Nicki Minaj - Va Va Voom (Explicit)
Music video by Nicki Minaj performing Va Va Voom (Explicit). ©: Cash Money Records, Inc., under exclusive license to Universal Republic Records, a division of UMG Recordings, Inc.
Nicki Minaj - Va Va Voom (Explicit)
Nicki Minaj - Va Va Voom (Explicit)
Nicki Minaj - Va Va Voom (Explicit)
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Ethics in Physics
Does ethics have a place in physics? For four hundred years, the answer has been a resounding no, yet the idea has never gone away completely. Over fifty years ago, Arthur Koestler, the brilliant Hungarian polymath, speculated that perhaps an ethical concept, purpose, might actually be a property of time. Then there are those who are convinced that there is evidence of intelligent design in the scheme of things, which of course is just another name for divine purpose.
Ethics in Physics
Nicki Minaj - Va Va Voom (Explicit)
Video Clips. Duration : 3.35 Mins.
Nicki Minaj - Va Va Voom (Explicit)
Music video by Nicki Minaj performing Va Va Voom (Explicit). ©: Cash Money Records, Inc., under exclusive license to Universal Republic Records, a division of UMG Recordings, Inc.
Nicki Minaj - Va Va Voom (Explicit)
Nicki Minaj - Va Va Voom (Explicit)
Nicki Minaj - Va Va Voom (Explicit)
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Infection Process and Infection Control
Throughout history man has faced the spread of infection, pondering its causes and how to treat it or prevent it. Infections have been known to affect major segments of the population, as did the plague in the Middle Ages. Although important advances have been made in understanding and treating infection, the threat of infection looms as large as it ever has. Newer enemies in the battle of infection emerge such as HIV and hepatitis C virus (HCV). Once-conquered enemies become resistant to treatment, as it the case of Mycobacterium tuberculosis and methicillin-resistant Staphylococcus aureus. Healthcare personnel typically encounter numerous patients on a daily basis, many of whom may be harboring these or other agents of infection. Measures to prevent the spread of infection must be taken in the course of treating all patients.
Infection Process and Infection Control
Nicki Minaj - Va Va Voom (Explicit)
Tube. Duration : 3.35 Mins.
Nicki Minaj - Va Va Voom (Explicit)
Music video by Nicki Minaj performing Va Va Voom (Explicit). ©: Cash Money Records, Inc., under exclusive license to Universal Republic Records, a division of UMG Recordings, Inc.
Nicki Minaj - Va Va Voom (Explicit)
Nicki Minaj - Va Va Voom (Explicit)
Nicki Minaj - Va Va Voom (Explicit)
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Comparison of the Excel Lookup, Vlookup and Hlookup Functions
The Excel lookup functions - Lookup, Vlookup and Hlookup - are three of the most useful functions supplied by Excel. However, many users get these functions (particularly the Lookup and Vlookup functions) mixed up, and as a result, find that their function doesn't work as expected.
Comparison of the Excel Lookup, Vlookup and Hlookup Functions
Nicki Minaj - Va Va Voom (Explicit)
Tube. Duration : 3.35 Mins.
Nicki Minaj - Va Va Voom (Explicit)
Music video by Nicki Minaj performing Va Va Voom (Explicit). ©: Cash Money Records, Inc., under exclusive license to Universal Republic Records, a division of UMG Recordings, Inc.
Nicki Minaj - Va Va Voom (Explicit)
Nicki Minaj - Va Va Voom (Explicit)
Nicki Minaj - Va Va Voom (Explicit)
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How Do I Decrease the File Size of a PDF File?
There are many factors that can affect the size of a PDF file. If you know these factors it would be possible for you to get the smallest possible file size of the PDF document that you create. The factors that affect the size of PDF files are the way the fonts are embedded, the images resolution and image type, and the version of the PDF and level of compression.
How Do I Decrease the File Size of a PDF File?
Nicki Minaj - Va Va Voom (Explicit)
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Nicki Minaj - Va Va Voom (Explicit)
Music video by Nicki Minaj performing Va Va Voom (Explicit). ©: Cash Money Records, Inc., under exclusive license to Universal Republic Records, a division of UMG Recordings, Inc.
Nicki Minaj - Va Va Voom (Explicit)
Nicki Minaj - Va Va Voom (Explicit)
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To make your PDF file smaller, Adobe suggests that you use "Save as" instead of "Save" every time you make a change in the PDF document you are creating. When you use the "Save" changes you make are appended to your file and this of course adds to the size. When you use the "Save as" you will overwrite the entire PDF and you are saving just the latest form of your document after the change.
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How Do I Decrease the File Size of a PDF File?
Another thing that could add to the size of the PDF file is the named destination, every ten or so named destinations could add at least a kilobyte to the PDF size. So if you think that named destinations is not that necessary in your PDF document do not include them.
How Do I Decrease the File Size of a PDF File?
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You can also use Adobe Acrobat's PDF optimizer to see which elements in your PDF document could take up the most space. To use the PDF Optimizer, click "Advanced" in the menu bar and select PDF Optimizer and then click on Audit Space Usage.
The elements in your PDF document that obviously add a lot to the total size of the final PDF are the images. as much as possible use vector-based graphics. Vector-based graphics are better than GIF in many aspects: they scale perfectly, look better, and take up lesser space. Avoid inseting bitmap graphics but if it could not be avoided, prepare it for maximum compression and minimum dimensions.
If you are creating PDF for the web and not for printing use RGB which has one less data channel than CMYK. As much as possible do not embed your fonts, fonts take up a lot of space.
Lastly, it is good to use newer versions of Acrobat because they have a more advanced compression system that can result in smaller PDF file size.
How Do I Decrease the File Size of a PDF File?
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This article aims to clarify the difference between the Excel Lookup, Vlookup and Hlookup functions, and to provide an overview of each of these functions.
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Comparison of the Excel Lookup, Vlookup and Hlookup Functions
All three functions - the Lookup, Vlookup and Hlookup - look up a value in a list and return the corresponding value in a second list. However, each of the functions is designed to work slightly differently.
Comparison of the Excel Lookup, Vlookup and Hlookup Functions
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One of the main considerations when selecting a lookup function is whether your data is organised along rows (i.e. horizontally) or down columns (i.e. vertically). If organised horizontally, you can use either the Hlookup function or Lookup function, and if your data is organised vertically, you can use either the Vlookup function or the Lookup function.
It is also important to consider what you need to happen if the function fails to find an exact match to your lookup value. If you only want to return a value if an exact match is found, and if not, you want an error message to be returned, you will need to use the Vlookup or the Hlookup function (with the range_lookup argument set to FALSE). However, if you want to accept the closest match to your lookup value, any of the three lookup functions can be used to do this.
The three functions (including the two different forms of the Lookup function) are summarised below:
Lookup Function
Vector Form: The vector form of the Excel Lookup function uses two vectors (i.e. Two one-dimensional arrays). As these two vectors are supplied to the function as separate arguments they can be horizontal or vertical, and there are no limitations on their positions in relation to each other.
Array Form: The array form of the Excel Lookup function uses a 2-dimensional array. The first column or row of the array is searched for the lookup value and the value returned is taken from the last column or row. Therefore, this function relies on the data being organised in a table, and the column or row containing the values to be returned must after (but not necessarily adjacent to) the column or row being searched.
Both forms of the Lookup function search for a closest match. I.e. If an exact match to the lookup value is not found, the closest match below the lookup value is used instead.
Vlookup Function
The Excel Vlookup function uses a 2-dimensional array with the data organised in columns. The first column of the array is searched for the lookup value and the user specifies which column the value returned is to be taken from. Therefore, similar to the array form of the Lookup function, the column containing the values to be returned must be to the right of the column to be searched.
The main difference between the Vlookup function and the array form of the Lookup function is that the Vlookup function can be set (via the range_lookup argument) to only return a value if it finds an exact match. However, by default (i.e. If the range_lookup argument is not supplied) the Vlookup function will, like the Lookup function, return the closest match below the lookup value.
Hlookup Function
The Excel Hlookup is the horizontal version of the Vlookup function. The function uses a 2-dimensional array, with the data arranged in rows. The first row of the array is searched for the lookup value and the user specifies which row the value returned is to be taken from. Therefore, in the Hlookup function, the row containing the values to be returned must be below (but not necessarily adjacent to) the searched row.
Also, like the Vlookup function, the Hlookup function uses the range_lookup argument, which allows the user to specify how the function behaves if it fails to find an exact match. If this argument is set to FALSE, the Hlookup function only returns a value if it finds an exact match to the lookup value. However, by default (i.e. If the range_lookup argument is not supplied or is set to TRUE), the Hlookup function will return use the closest match below the lookup value.
It is important to note that in all of the above functions, if you are not requesting an exact match to your lookup value, the data in the column or row to be searched must be sorted into ascending order. If it isn't, this could cause your function to return unexpected results.
Comparison of the Excel Lookup, Vlookup and Hlookup Functions
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Below we explain the infection process and describe infection control measures needed to protect healthcare patients, staff, visitors, and those who do business with healthcare facilities.
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Infection Process and Infection Control
What Is Infection?
Infection Process and Infection Control
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Our environment is full of microorganisms (microscopic organisms) referred to as microbes. Microbes include bacteria, fungi, protozoa, and viruses. The majority of microbes are nonpathogenic, meaning they do not cause disease under normal conditions. Microbes that are capable of causing disease (ie., pathogenic) are called pathogens. If a pathogen invades the body and the conditions are favorable for it to multiply and cause injurious effects or disease, the resulting condition is called an infection. The pathogen responsible for causing the infection is referred to as the infectious or causative agent. Infection can be local (restricted to a small area of the, body) or systemic, in which the entire body is affected.
Communicable Infections
Some pathogenic microbes cause infections that can be spread from person to person. These infections are called communicable infections and the diseases that result are called communicable diseases. A division of the U.S. Public Health Service called the Centers for Disease Control and Prevention (CDC) is charged with the investigation and control of various diseases, especially those that are communicable and have epidemic potential. The CDC recommends safety precautions to protect healthcare workers and others from infection.
Nosocomial Infections
Approximately 5 % of patients in the United States are exposed to and contract some sort of infection after admission to a hospital or other healthcare facility. These hospital or healthcare facility-acquired infections are called nosocomial infections. Nosocomial infections can result from contact with infected personnel, other patients, and visitors, or contaminated equipment. The most common nosocomial infection in the United States is urinary tract infection. The Hospital Infection Control Practice Advisory Committee (HICPAC), established in 1991, advises the CDC on updating guidelines regarding prevention of nosocomial infection.
Source Of Infection
The source is the origin of infectious microorganisms, also called the reservoir. Sources of infectious microbes include infected humans or anima1s and contaminated articles and equipment. In a healthcare setting, human sources of infectious microbes can be patients, personnel, or visitors, and can include those with active disease, those whose disease is in the incubation period, and those who are chronic carriers of a dis- ease. Another potential source of infectious microbes is a person's own normal flora (microorganisms that normally live on the skin and other areas of the human body).
Inanimate objects such as contaminated equipment can be a major source of infection in a healthcare setting. Whether or not an inanimate source is capable of transmitting infection depends upon the amount of contamination, the viability or ability of the organism to survive on the source, the virulence or degree to which an organism is capable of causing disease, and the amount of time elapsed between when the source was contaminated and when it was contacted.
For example, the virus that causes hepatitis B is much more virulent, or capable of causing disease from a small amount of infective material, than HIV, the virus that causes AIDS. It is also more viable, meaning it is capable of surviving longer on surfaces than is HIV. However, if a long enough time elapses from the time of contamination until contact by a susceptible host, the microbe is no longer alive and is not capable of transmitting disease.
Modes Of Transmission
There are five basic modes or routes of infection transmission: contact, droplet, airborne, vehicle, and vector. The same microbe can be transmitted by more than one route.
Contact transmission
Contact transmission is the most frequent mode of infection transmission. There are two types of contact transmission, direct transmission and indirect transmission.
Direct contact transmission involves direct, physical transfer of a pathogenic microbe to a susceptible host through close or intimate contact such as touching or kissing.
Indirect contact transmission involves personal contact by a susceptible host with contaminated inanimate objects such as patient bed linens, clothing, dressings, and eating utensils. It includes contact with phlebotomy equipment such as gloves, needles, specimen tubes, and phlebotomy carts and trays. It also includes less obvious contaminated objects such as doorknobs and faucet handles. The transfer of infectious microbes from contaminated hands to a susceptible host is also considered indirect contact transmission.
Droplet transmission
Droplet transmission involves the transfer of the infective microbe to the mucous membranes of the nose or mouth or the conjunctiva (mucous membranes) of the eyes of a susceptible individual through sneezing, coughing, or talking by an infected per- son. Droplet transmission can also occur during procedures such as suctioning and throat swab collection. It differs from airborne transmission in that droplets do not travel more than 3 feet, and do not remain suspended in air.
Airborne transmission
Airborne transmission involves dissemination of droplet nuclei. Droplet nuclei are the residue of evaporated droplets generated by sneezing, coughing, or talking. Infectious microbes within droplet nuclei can remain viable even though suspended in the air or in dust particles for long periods. Microbes carried in this manner can become widely dispersed before being inhaled by or deposited on a susceptible host. For this reason, special air handling and ventilation are required for rooms of patients having infections with airborne transmission. Persons entering the room must wear a snug-fitting mask with a special filter. M. tuberculosis, rubeola virus, and varicella virus are the most common microorganisms transmitted by the airborne route.
Vector transmission
Vector transmission involves the transfer of the microbe by an insect, arthropod, or animal. An example of vector transmission is the transmission of malaria by a mosquito or the plague by rodent fleas.
Vehicle transmission
Vehicle transmission involves the transmission of the infective microbe through contaminated food, water, or drugs. Examples of vehicle transmission are salmonella infection from handling contaminated chicken and shigella infection from drinking contaminated water. The transmission of hepatitis and HIV through blood transfusion is also considered vehicle transmission.
Susceptible Host
A susceptible host is someone who has decreased ability to resist infection. Susceptibility is affected by age, health, and the immune status of the individual. For example, newborns whose immune systems are not yet developed and old people whose immune systems are no longer functioning properly are more susceptible to infections. In addition, disease, antibiotic treatment, and immunosuppressive drugs may compromise a person's resistance to infection. Procedures such as surgery, anesthesia, and insertion of catheters can also leave a patient more susceptible to infection. Recovery from a particular virus or vaccination against a virus also affects susceptibility. A healthy person who has received a vaccination against a disease-causing virus, or who has recovered from infection with a particular virus, has developed antibodies against that virus and is considered to be immune, or unlikely to develop the disease.
Breaking The Chain Of Infection
Breaking the chain of infection means stopping infections at the source, eliminating means of transmission, and reducing or eliminating the susceptibility of potential hosts. Ways to prevent transmission of infectious microbes are proper hand washing; use of gloves, gowns, masks, and other protective equipment when indicated; proper waste disposal; isolation procedures; insect and rodent control; and decontamination of surfaces and instruments. Susceptibility of potential hosts can be reduced through proper nutrition, reduction of stress, and immunization against common pathogens.
Infection Process and Infection Control
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Part of the difficulty here is to define what is meant by ethics. There is first of all ethics as a code of acceptable social behavior, like an agreement by most people in the world that eating your enemies is no longer considered the right thing to do. There can be little argument that this kind of ethics has no place in science.
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Ethics in Physics
Then there is John Smith over here who firmly believes that the Bible is the literal word of God and that He is in charge of where creation is going. If physics does not recognize this, then physics is wrong and must find a place for God in the scheme of things. However, over there is Jane Doe who thinks the Bible is suspect because it was written by a lot of cantankerous, opinionated old men. Women had no part in writing this document, which is probably why God himself is pictured as a man. She does not believe any of it and thinks that arguments about purpose are typical male arguments that lead nowhere. Both John and Jane are probably influenced in their beliefs by their personal histories. Perhaps John came from a very traditional Christian family, while Jane came from a background of rebels and iconoclasts. But there is one thing they both have in common: their beliefs are purely personal and thus subjective. It is true that John thinks his beliefs are grounded in a revealed truth that exists quite apart from him and is thus objective, but that is simply his own personal belief, which is contradicted by Jane's own personal belief. Whatever the subject of their personal beliefs, neither John nor Jane can show any independent proof that their beliefs reflect an outside truth which is axiomatically self-evident.
Ethics in Physics
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Modern physics today agrees that what it deals with in the world of natural phenomena (what is measurable and quantifiable) is based on our sense perceptions, and that sense perceptions are fundamentally subjective in nature. That being the case, physics is quite right in excluding any subjective ethical concepts from science, because such ethics are not governed by scientific rules of evidence. As a leading physicist of the twentieth century, Werner Heisenberg, put it: "Science deals with the objective, physical world.... Religion, on the other hand, deals with the world of values. It considers what ought to be or what we ought to do, not what is. In science, we are concerned to discover what is true or false; in religion what is good or evil, noble or base. Science is the basis of technology, religion the basis of ethics."
Ethics can only be thought of in a scientific context when physics has reached the point where the subjective reality of physical phenomena is no longer enough to explain the origin of these phenomena. Physics tried very hard, for instance, to reach the origin of matter within this world. For many years, this origin of matter was thought to be the ultimate, irreducible particle, namely the atom. Then it was discovered that the atom itself consisted of smaller particles, but even these, such as the proton, were then found to be capable of further division into quarks. It became evident that the size of particles depended on the amount of energy that could be directed at them. If this energy were high enough, even smaller particles would probably result. So physics came up with the concept of the string particle as the ultimate matter particle. It is defined as having only one dimension, length. It therefore cannot be divided any further, even theoretically. However, nothing of only one dimension can exist in our ordinary subjective world of sense perceptions. If it exists at all, therefore, it must exist in some other reality, not our subjective kind which depends on us and our sense perceptions.
This argument shows that physics has now reached the point where a reintroduction of objective reality is becoming necessary. The book, Galileo's Shadow, on which this article is based, explores these realities in greater detail and how they effect ethical concepts. If ethics can be removed from human subjectivity and considered in an objective setting, that is a setting which has nothing to do with our human presence, it might then possibly have something to do with physics, if physics has reached the same setting.
Such possibilities are explored in Galileo's Shadow, which reaches the conclusion that an ethical concept such as purpose might indeed be thought of in connection with science, if it is an inherent, constituent property of the universe. This concept would not "explain" such a purpose in human terms, it would merely point to its likely existence as a sort of vector, or direction, in which the universe is developing. Its relevance to science would lie in the alternative it offers to purely random chance developments which, today, are the only acceptable engines of evolution.
Ethics in Physics
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What is Desktop Publishing (DTP)? In the 1980s, it was a common term applied to digital publishing systems. These systems were developed to replace large, pre-press, specialist design and compositing systems.
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The Best Computer For Graphic Design
Graphic designers rely heavily on computers whether these are Windows PCs or Apple Macs. Whichever computer a graphic designer chooses to use, he/she will opt for the best computer that he/she can purchase. Graphic designers will rarely choose cheap computer hardware.
The Best Computer For Graphic Design
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Back in the eighties, Macs were the only choice for designing and printing. Almost all design layout and graphics software was developed for Macs only or even if the software could be used in Microsoft Windows PC, it was much more reliable on a Mac. Additionally, at that time, Macs were associated with the different technologies used in the prepress and Windows PC was just not a practical choice. Today, modern versions of Mac OS X and Windows allow graphics designers to use design software either in a Mac or PC - they are no longer forced to choose one over the other.
Many graphic designers are not IT experts and making a decision on which computer to buy can be quite daunting. Of course, if money is not a problem, the decision would simply be to buy the most expensive Apple Mac or Windows PC. But most designers cannot afford to do that. In fact, some creative professionals have budgets for second hand equipment only. What really matters to these graphic designers are issues that regular computer users do not even have to think about. These are printer color accuracy, monitor calibration, hard disk speed and external storage devices for gigabytes of data.
Recent studies show that the top 5 computers for graphic design are a mix of Macs and PCs and both laptop and desktop computers fall in this category. But just like any product that a consumer buys, it really is the personal preference of the designer whether he/she will use a desktop computer or a laptop. The important thing is that the user/graphic designer has the appropriate software for the type of computer that he/she wants to purchase.
The Top 5 computers for graphic design are:
Mac Pro Desktop
The Mac line of computers is still widely preferred by most graphic designers. According to Apple, the latest Mac Pro features the all new quad-core Intel Xeon "Nehalen" processor which makes the job of a graphic designer much easier. Apple states further that the new Mac Pro is up to 1.9 times faster than its predecessor. Each processor has an integrated memory controller that allows the processors to have faster access to stored data in the computer's memory, with memory latency decreased by up to 40 percent. This feature will save a lot of time for designers when they do their work.
MacBook Pro Laptop
The MacBook Pro Laptop comes in 13, 15 and 17 inch sizes. It has high-performance NVDIA graphics and LED backlit display which makes editing graphics easier and clearer. This latest model has battery power that lasts up to 8 hours (on 17-inch version). It is powered by the Intel Core 2 Duo processor.
Dell Studio XPS Desktop
The Dell Studio XPS Desktop features the Intel Core i5 and i7 processors. If you plan on working with intensive video or 3D editing, you can have an upgrade to the 16GB Dual Channel DDR3 SDRAM. But its base 3GB memory will enable you to edit photos, create vector or raster designs with ease. Its high-definition ATI graphics card creates clear, precise and flawless graphics - just what a graphic designer needs.
Toshiba Qosmio Laptop
The Toshiba Qosimo is an affordable solution to your graphic design needs. It is powered by either the Intel Core i7 or i5 processor making it easier to create flawless graphics. It has a high-end NVIDIA GeForce graphics card, which ensures that you can clearly see every pixel and frame that you edit. It has a 6GB DDR3 1066MHz memory and a 1GB GDDR5 discrete graphics memory.
HP Pavilion Elite Desktop
The HP Pavilion Elite Desktop is an affordable computer. It is powered by either an AMD Athlon or an Intel Core processor that ranges from an X4 630 quad-core (Athlon) to an i7-980X six-core Extreme Edition (Intel). All HP Pavilion Elite Desktop computers come with genuine 64-bit Windows 7 for the latest technology. Memory ranges from 4GB up to 9GB which guarantees smooth and effortless run of the high-end graphics that you use.
The Best Computer For Graphic Design
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Below we explain the infection process and describe infection control measures needed to protect healthcare patients, staff, visitors, and those who do business with healthcare facilities.
Vector
Infection Process and Infection Control
What Is Infection?
Infection Process and Infection Control
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Our environment is full of microorganisms (microscopic organisms) referred to as microbes. Microbes include bacteria, fungi, protozoa, and viruses. The majority of microbes are nonpathogenic, meaning they do not cause disease under normal conditions. Microbes that are capable of causing disease (ie., pathogenic) are called pathogens. If a pathogen invades the body and the conditions are favorable for it to multiply and cause injurious effects or disease, the resulting condition is called an infection. The pathogen responsible for causing the infection is referred to as the infectious or causative agent. Infection can be local (restricted to a small area of the, body) or systemic, in which the entire body is affected.
Communicable Infections
Some pathogenic microbes cause infections that can be spread from person to person. These infections are called communicable infections and the diseases that result are called communicable diseases. A division of the U.S. Public Health Service called the Centers for Disease Control and Prevention (CDC) is charged with the investigation and control of various diseases, especially those that are communicable and have epidemic potential. The CDC recommends safety precautions to protect healthcare workers and others from infection.
Nosocomial Infections
Approximately 5 % of patients in the United States are exposed to and contract some sort of infection after admission to a hospital or other healthcare facility. These hospital or healthcare facility-acquired infections are called nosocomial infections. Nosocomial infections can result from contact with infected personnel, other patients, and visitors, or contaminated equipment. The most common nosocomial infection in the United States is urinary tract infection. The Hospital Infection Control Practice Advisory Committee (HICPAC), established in 1991, advises the CDC on updating guidelines regarding prevention of nosocomial infection.
Source Of Infection
The source is the origin of infectious microorganisms, also called the reservoir. Sources of infectious microbes include infected humans or anima1s and contaminated articles and equipment. In a healthcare setting, human sources of infectious microbes can be patients, personnel, or visitors, and can include those with active disease, those whose disease is in the incubation period, and those who are chronic carriers of a dis- ease. Another potential source of infectious microbes is a person's own normal flora (microorganisms that normally live on the skin and other areas of the human body).
Inanimate objects such as contaminated equipment can be a major source of infection in a healthcare setting. Whether or not an inanimate source is capable of transmitting infection depends upon the amount of contamination, the viability or ability of the organism to survive on the source, the virulence or degree to which an organism is capable of causing disease, and the amount of time elapsed between when the source was contaminated and when it was contacted.
For example, the virus that causes hepatitis B is much more virulent, or capable of causing disease from a small amount of infective material, than HIV, the virus that causes AIDS. It is also more viable, meaning it is capable of surviving longer on surfaces than is HIV. However, if a long enough time elapses from the time of contamination until contact by a susceptible host, the microbe is no longer alive and is not capable of transmitting disease.
Modes Of Transmission
There are five basic modes or routes of infection transmission: contact, droplet, airborne, vehicle, and vector. The same microbe can be transmitted by more than one route.
Contact transmission
Contact transmission is the most frequent mode of infection transmission. There are two types of contact transmission, direct transmission and indirect transmission.
Direct contact transmission involves direct, physical transfer of a pathogenic microbe to a susceptible host through close or intimate contact such as touching or kissing.
Indirect contact transmission involves personal contact by a susceptible host with contaminated inanimate objects such as patient bed linens, clothing, dressings, and eating utensils. It includes contact with phlebotomy equipment such as gloves, needles, specimen tubes, and phlebotomy carts and trays. It also includes less obvious contaminated objects such as doorknobs and faucet handles. The transfer of infectious microbes from contaminated hands to a susceptible host is also considered indirect contact transmission.
Droplet transmission
Droplet transmission involves the transfer of the infective microbe to the mucous membranes of the nose or mouth or the conjunctiva (mucous membranes) of the eyes of a susceptible individual through sneezing, coughing, or talking by an infected per- son. Droplet transmission can also occur during procedures such as suctioning and throat swab collection. It differs from airborne transmission in that droplets do not travel more than 3 feet, and do not remain suspended in air.
Airborne transmission
Airborne transmission involves dissemination of droplet nuclei. Droplet nuclei are the residue of evaporated droplets generated by sneezing, coughing, or talking. Infectious microbes within droplet nuclei can remain viable even though suspended in the air or in dust particles for long periods. Microbes carried in this manner can become widely dispersed before being inhaled by or deposited on a susceptible host. For this reason, special air handling and ventilation are required for rooms of patients having infections with airborne transmission. Persons entering the room must wear a snug-fitting mask with a special filter. M. tuberculosis, rubeola virus, and varicella virus are the most common microorganisms transmitted by the airborne route.
Vector transmission
Vector transmission involves the transfer of the microbe by an insect, arthropod, or animal. An example of vector transmission is the transmission of malaria by a mosquito or the plague by rodent fleas.
Vehicle transmission
Vehicle transmission involves the transmission of the infective microbe through contaminated food, water, or drugs. Examples of vehicle transmission are salmonella infection from handling contaminated chicken and shigella infection from drinking contaminated water. The transmission of hepatitis and HIV through blood transfusion is also considered vehicle transmission.
Susceptible Host
A susceptible host is someone who has decreased ability to resist infection. Susceptibility is affected by age, health, and the immune status of the individual. For example, newborns whose immune systems are not yet developed and old people whose immune systems are no longer functioning properly are more susceptible to infections. In addition, disease, antibiotic treatment, and immunosuppressive drugs may compromise a person's resistance to infection. Procedures such as surgery, anesthesia, and insertion of catheters can also leave a patient more susceptible to infection. Recovery from a particular virus or vaccination against a virus also affects susceptibility. A healthy person who has received a vaccination against a disease-causing virus, or who has recovered from infection with a particular virus, has developed antibodies against that virus and is considered to be immune, or unlikely to develop the disease.
Breaking The Chain Of Infection
Breaking the chain of infection means stopping infections at the source, eliminating means of transmission, and reducing or eliminating the susceptibility of potential hosts. Ways to prevent transmission of infectious microbes are proper hand washing; use of gloves, gowns, masks, and other protective equipment when indicated; proper waste disposal; isolation procedures; insect and rodent control; and decontamination of surfaces and instruments. Susceptibility of potential hosts can be reduced through proper nutrition, reduction of stress, and immunization against common pathogens.
Infection Process and Infection Control
