Microorganisms

**invisible to the naked eye, they can be nonpathogenic and parasitic life forms.

**converts matter into simple forms through decay converting them to higher forms that can be used as nutrients.

Symbiosis or symbiont if referring to both organisms

relationship between microorganisms (indigenous flora) and humans

Mutualism, Commensalism, Parasitism

categories of symbiosis

indigenous microflora (also referred to as opportunistic pathogens)

microbes that live on the skin an inside the human body. They include bacteria, fungi, viruses, and protozoa

*harmless unless given the chance to enter the body through a surgical wound"

infection

multiplication of organisms in the tissues of a host

*may affect not only a patient but also any individual who has contact with the health care facility, including health care workers and visitors

nosocomial infection

any infection that develops while a patient is in the health care facility

**a broadened categorization - termed HAI (health care-associated infections)

25% not evident until after discharged from hospital

Mutualism

both organisms benefit from and depend on one another to a certain extent.

escherichia coli (E coli)- colonizes within the human intestine, obtains nutrients from the food that humans eat. Produces vitamin K for blood-clotting.

commensalism

one organism benefits but second organism neither benefits nor is harmed.

indigenous microflora is an example

Neutralism

subcategory of commensalism - two organisms occupy the same area with no effect on each other

Antagonism

subcategory of commensalism - one microorganism inhibits or interferes with the growth of another

example: a microbe produces waste products that are toxic to the neighboring microbes

competitive exclusion

in commensalism symbiosis the second organism is usually neither benefited or harmed. To a certain extent the second organism can be benefited if the organism is taking up space and preventing other potentially harmful microbes from colonizing.

Parasitism

one organism benefits and the host is harmed

examples: intestinal worms, nosocomial infections (UTI), and airborne viruses (common cold)

** commensal symbiosis can change to parasitism if the microbe becomes opportunistic by entering through a surgical skin incision

pathogens

microorganisms that cause an infection

UTI (staphylococcus S. aureus bacteria)

#1 nosocomial infection (HAI) - 32%

Surgical site infections

22% of HAI

pneumonia (lung infections)

15% of HAI

bloodstream infections

14% of HAI

eukaryotes

a group of how all living cells are classified - cellular structure is complex.

includes: protozoa, fungi, green, brown, and red algae, and all plant and animal cells

prokaryotes

a group of how all living cells are classified - cellular structure is less complex organisms whose organelles are not membrane bound.

bacteria

all are prokaryotes and they divide by binary fission (the division of two identical cells)

morphology

characteristics of bacteria

size, shape, and arrangement

coccoid

coccus = singular

cocci = plural

round shaped bacteria

diplococci

paired bacteria

streptococci

chain of bacteria

staphylococci

cluster of bacteria

coccobacilli

a bacterial cell intermediate in morphology between a coccus and a bacillus - rod shaped, but also short and wide that they resemble cocci which is round

bacillus

rod-shaped bacteria

spirilla

spiral-shaped bacteria

L-form

bacteria that lose normal shape due to adverse environmental conditions; once normal conditions are reestablished cells revert to normal shape.

characteristics of bacteria

morphology, growth(varies with type of agar) motility, nutritional requirements, oxygen requirements (and carbon dioxide), pathogenicity, metabolism(secretion of waste products), proteins, genetics, staining, spore forming (sporulation)

motility: characteristic of bacteria

flagella: long thin structures.. whipping motion

cilia: fine, short, hairlike extension located on the surface of the cell; rhythmic movement

oxygen requirements - characteristic of bacteria

obligate aerobes; require level of oxygen found in a typical room

microaerophiles; require oxygen but at a lower level than room air 5%

obligate anaerobes; will not grow if there is any amount of oxygen present in the environment

facultative anaerobes; able to survive in an environment that contains oxygen or no oxygen

aerotolerant anaerobes; grow best in environment without oxygen - can survive up to 15% oxygen

capnophiles; grow best in high concentrations of carbon dioxide

staining - characteristic of bacteria

simple stain; used to determine basic shape and structures of cell; single dye such as methylene blue is used and the cell is rinsed with water.

Gram stain; cells are stained with crystal violet; washed with ethanol that removes purple stain from bacteria that don't retain the stain; red dye safranin is applied; specimen is rinsed with water.

*Gram positive bacteria retain the crystal violet and therefore are purple color.

*Gram negative bacteria do not retain the crystal violet an are red from the safranin stain.

**Gram-variable bacteria, Mycobacterium tuberculosis do not consistently stain red or purple

**Acid-fast stain; used to identify bacteria classified in the genus Mycobacterium. Red dye (carbolfuchsin) is retained by acid-fast bacteria

Staphylococcus - S. aureus

******Most common post-op bacterial infection (pathogen) - SSI

gram-positive coccus - common in the flora of the skin, hair and nares of nose

toxic shock syndrome

osteomyelitis

endocarditis

Staphylococcus - S. epidermis

IV catheter infections, UTIs, prosthetic device infections, subacute bacterial infections, endocarditis

Streptococcus - S. pneumoniae

bacterial pneumonia

Streptococcus - S. pyogenes

rheumatic fever, necrotizing fasciitis, strep throat, tonsillitis, scarlet fever

Aerobic gram-negative cocci, coccobacilli

Neisseria gonorrhoeae - pelvic inflammatory disease deading to salpingitis

Moraxella catarrhalis - otitis media in children

spore forming - characteristic of bacteria

clostridium is an example

*when conditions are unfavorable(extreme temps, dry, lack of food) the genetic material of the cell is enclosed in a protein capsule

*can survive for a long time until favorable conditions are reestablished, bacteria returns to vegetative state and able to grow

*not to be confused with reproduction, it is a method of bacterial survival

*are difficult to destroy; sterilization processes must be able to kill it

Aerobic gram-positive bacilli, coccobacilli, coryneform bacilli

(B. anthracis, Listeria, monocytogenes, lactobacillus species, corynebacterium diphtheriae)

anthrax, meningitis, bacteremia, endocarditis, respiratory and cutaneous diptheria

Aerobic, microaerophile gram-negative bacilli spirochetes

Legionella pneumophila

Pontiac fever (influenza-like illness) Legionnaires' disease (severe form of pneumonia)

Aerobic, microaerophile gram-negative bacilli spirochetes

pseudomonas aeruginosa

deep-tissue health care-associated infections in patients with burns, deep puncture wounds, and open bone fractures

Aerobic, microaerophile gram-negative bacilli, spirochetes

Helicobacter pylori

chronic gastritis, stomach ulcers, peptic ulcers

Facultative anerobic gram-negative bacilli

Haemophilus influenzae

Bacterial meningitis (primary cause in infants and children), respiratory tract infections, bacterial pneumonia (elderly), septic arthritis, cellulitis, eye infections

Facultative anaerobic gram-negative bacilli

Escherichia coli

UTIs, sepsis, neonatal meningitis

Mycobacteria

Mycobacterium tuberculosis

Tuberculosis

Chlamydia

C. trachomatis

Conjunctivitis, ocular lymphogranuloma venereum, lymphogranuloma venereum, nongonococcal urethritis, postgonococcal urethritis, infant pneumonia

Tuberculosis - mycobacterium tuberculosis

transmitted through airborne droplet nuclei, usually infect the lungs but may also infect the kidneys, bone, joints, or skin.

annual testing

fit test for mask

require isolation precautions when surgical procedures are performed - PPE plus a NIOSH approved respirator

patient advised how he/she can prevent cross-contamination

Viruses

nonliving particles that are completely reliant on the host cell for survival

*obligate intracellular parasites

*replication is directed by the nucleic acid within the host cell

*contain either DNA or RNA and a protein coat that encases the nucleic acid

*depend on the protein production of the host cell; does not contain the enzymes required for the production of energy

*no antibiotics are given

Capsid

A protein covering that surrounds and protects the virus's DNA or RNA and aids in the attachment of the viral cell to the host cell

*composed of protein molecules called capsomeres

Viruses enter the body through the following methods

inhalation of respiratory droplets, exchange of body fluids, ingestion of food or water, bites by arthropod vectors

the capsid and the nucleic acid together are referred to as

nucleocapsid

Common pathogens in the OR

Hepatitis B (HBV) - blood, body fluids - liver cancer

Hepatitis C - blood-borne (silent killer - prior to 1980 no testing of blood) - liver cancer

Hepatitis D (Delta)

Human immunodeficiency Virus (HIV) - blood or other bodily fluids

Herpes simplex virus (HSV) - contact with fluid from lesions

Papillomavirus - direct contact with another person

Cytomegalovirus (CMV) - direct contact with body fluids

Cruetzfeldt-Jakob Disease (CJD) - exact mode of transmission unknown - prions (20hr) sterilization or properly dispose of instrumentation

Prion

"proteinaceous infectious particle"

do not contain DNA or RNA

changes normal PrP (a protein) from noninfectious spiral shape, alpha-helical, to the infectious folded shape called the beta-sheet

attack the brain (neurons) and cause diseases called subacute spongiform encephalopathies

**more common in animals, and include the two common forms of scrapie(disease that infects sheep and goats) and bovine spongiforms encephalopathy (commonly called mad cow disease)

in rare cases can be inherited as a mutant gene or sporadic case

CJD

20 year incubation time, mimics Alzheimer's disease, no vaccine or cure, definitive diagnosis is through histologic examination of affected brain and lymphoid tissue

WHO - recommends use of single-use, disposable instruments and the destruction of all reusable instruments

vCJD or nvCJD

a new variant strain has a younger median age of onset at 28 years of age and longer duration of symptoms of 13 -14 months

more chemical indicators of prion accumulation in the neural and lymphoid tissues

two categories of parasitic human pathogens

Unicellular protozoans and Multicellular protozoans

Parasitology

the study of invertebrates that cause disease

Helminths

metazoans category - endoparasites properly known as worms

most common worms are tapeworms, flukes, and roundworms

primary route of transmission = food or water contained eggs

also transfers by skin penetration, fecal-oral contamination, or arthropod bite

cause intestinal blockage and may rupture intestinal wall

increase in helminth infection

human mobility, immigration from Third World countries

damage of body tissues and organs to the point of surgery

example: cysticeri (Taenia solium) pork tapeworms that can migrate out of the intestinal tract and travel to muscle and brain tissue, and the eyes.

worms

Protozoa

unicellular eukaryotes

causes malaria and chronic sleeping sickness

the intestinal form of these are transmitted by fecal-oral route and are often responsible for infections in crowded environments such as day care centers and underdeveloped countries.

Entamoeba histolytica

a protozoa that causes amebic dysentery

patients who are scheduled to undergo a sigmoidoscopy or colonoscopy

Trichomonas vaginalis (T. vaginalis)

a unicellular anaerobic protozoan that is part of the normal flora of the vagina and urethra

If acidity of vagina is upset, protozoan population will grow causing trichomoniasis (usually a sexually transmitted disease)

The study of fungi

Mycology

unicellular yeast or multicellular molds and mushrooms

reproduce sexually or asexually by producing spores

Fungi

fungal diseases

called mycoses (mycosis=plural)

opportunistic pathogens that cause disease when the host is immunocompromised common in AIDS patients

The majority of fungal diseases

Bread mold

zygomycosis

rapidly progressive and destructive disease which causes extensive damage to the bone and tissues of the face. If the organism enters the bloodstream and destroys the cranial bones, the brain tissue will be invaded.

rhinocerebral zygomycosis

candida albicans

vaginal yeast infection

trench mouth (thrush)

immunocompromised patients should be monitored for infection

intraoperative guidelines for suspected CJD patients

use disposable equipment

avoid use of power instruments

use neutral zone for passing sharps

sterile attire-gloves, face shields, knee-high impervious shoe covers

clean body fluid spills with sodium hydroxide (household bleach)

specimens into specimen container, then place biohazard bag labeled properly with this disease

per surgeon's order: clean patient's head with 1 molar sodium hydroxide at the end of procedure

postoperative guidelines for suspected CJD patients

place reusable instruments in impervious container, biohazard bacs, and labels with this disease according to hospital policy (policy may be disposal)

bodily fluids in biohazard bags labeled with this disease and kept separate from other red bags; notify environmental services to collect bags.

sharps in a separate container labeled with this disease; notify environmental services to collect and incinerate container

CJD environmental cleaning protocols

decontaminate all OR surfaces with 1 molar sodium hypochlorite for 60 min.. rinse with water then give routine cleaning

visible bioburden decontaminated with 1:10 dilution of 5.25% sodium hypochlorite...followed by routine cleaning with disinfectant

most hospital infections are transmitted by bacteria (UTI), viruses, and occasionally fungi and parasites

Frequent handwashing helps to eliminate these primary agents

transmission based precautions help prevent

cross-contamination of patients when the disease process has been diagnosed

may even be required to change scrubs in the event of MRSA or VRE

Direct contact - Indirect contact - Droplet particle size(>5um) - Airborne spread particle size (<5 um)

SSI (surgical site infection) sources at the time of surgery, rather than at some point after surgery

divided into two groups:

environmental: (1) personnel, (2)the environment, and (3)contaminated instrumentation

endogenous: patient's endogenous flora

SSI sources - environmental - (1)personnel

personnel hair, skin, and nares are reservoirs of bacteria, which may be discharged in particle form into the air and therefore pose a risk of these to the patient.

gowns and drapes cover the skin on areas of the body other than the hands. The primary purpose of wearing PPE around the OR table is to provide a barrier to contamination, both from personnel to patient and from patient to personnel. This is termed surgical conscience

SSI sources - environmental - (2)environment

FOMITES

A second source of microbial transmission is through the air and through these inanimate objects that may contain infectious microorganisms including walls, floors, cabinets, furniture and equipment

SSI sources - environmental - (3)contaminated surgical instrumentation

contaminated antiseptic solutions, contaminated wound dressings, and contaminated or improperly sterilized surgical instruments

SSI sources - endogenous - patient's endogenous flora

cannot sterilize your skin

two primary sources of SSI risk to the patient:

1. encountered in contaminated procedures

2. resident (the normal) flora of the skin

Preoperative prophylaxis with antibiotics

shown to reduce SSIs

carriers of S. aureus are at particular risk for SSI

Factors that increase SSI

age: pediatric or geriatric lower immunological defenses

obesity: diminished blood flow

general health: poor health=predisposed to infection

carriers of S. aureus or MRSA: greater risk from their own flora

remote infections: other body site infections; will travel

preoperative hospitalization: duration of operative stay

preexisting illness and related treatment: rates are higher in patients with compromised immune systems from preexisting illness, patients on meds., etc.

preoperative preparations for suspected CJD patients

notify all units

remove all unnecessary equipment and supplies from the OR as possible and everything else as far from the OR table as possible

cover all OR surfaces; electrical cords with sterile plastic sleeves

Other factors that may contribute to an increased likelihood of SSI

malnutrition, tobacco use, diabetes, malignancy, immunosuppression, high staph carriers, ruptured appendix (fecal matter in the colon)

Procedure-related risk factors that increase the danger of SSI

Preoperative hair removal: use of razors carries a greater risk than the use of clippers. Blades leave many small cuts on the skin, allowing bacteria easier access for colonization. Depilatory cream is a safer alternative

Type of procedure: clean-contaminated (class II), contaminated (class III), and dirty (class IV), cases carry a higher risk of infection

Duration of procedure: longer anesthetic and operative times have an accompanying increase in time for bacterial contamination to occur, increased tissue damage, and greater immunosuppression, fatigued team members which may break sterile technique

AST recommended standards of practice

use of eye protection, laundering of scrub attire, wearing jewelry, wearing the lab coat/cover gown, hand hygiene and fingernails, head covers, shoe covers (during operation)