انت هنا الان : شبكة جامعة بابل > موقع الكلية > نظام التعليم الالكتروني > مشاهدة المحاضرة

Hospital Infection Control - Lecture no. 2 Epidemiology Of Nosocomial Infections

Share |
الكلية كلية التمريض     القسم كلية ذات القسم الواحد     المرحلة 4
أستاذ المادة عمار عباس شعلان الحميري       16/10/2017 12:50:47
hospital infection control
lecture no. 2
epidemiology of nosocomial infections
definitions of nosocomial infections
nosocomial infections, also called “hospital-acquired infections”, are infections acquired during hospital care which are not present or incubating at admission.
infections occurring more than 48 hours after admission are usually considered nosocomial.
nosocomial infections
5-10% of patients admitted to acute care hospitals acquire infections
2 million patients/year
¼ of nosocomial infections occur in icus
90,000 deaths/year
attributable annual cost: $4.5 – $5.7 billion
pathogenesis of nosocomial infections
3 ingredients
susceptible host
virulent organism
portal (mode) of entry
pathogenesis of nosocomial infections ns
host defenses depressed by underlying disease or treatment, malnutrition, age
anatomic barriers breached (iv’s, foleys, vents etc.)
exposure to virulent pathogens
many resistant to multiple antibiotics

the inanimate environment can facilitate transmission
sources of pathogens in nosocomial infections
reactivation of latent infection: tb, herpes viruses
less common

endogenous: normal commensals of the skin, respiratory, gi, gu tract
common
exogenous
inanimate environment: aspergillus from hospital construction, legionella from contaminated water
animate environment: hospital staff, visitors, other patients
cross transmission- common

mechanisms of transmission
contact: direct (person-person), indirect (transmission through an intermediate object contaminated instruments
cross transmission
airborne: organisms that have a true airborne phase as pattern of dissemination (tb, varicella)
common-vehicle: common animate vehicle as agent of transmission (ingested food or water, blood products, iv fluids)
dropinglet: brief passage through the air when the source and patient are in close proximity
arthropod
microorganisms
bacteria

commensal bacteria
found in normal flora of healthy humans.
these have a significant protective role by preventing colonization by pathogenic microorganisms.
some commensal bacteria may cause infection if the natural host is compromised. for example, cutaneous coagulasenegative staphylococci cause intravascular line infection and intestinal escherichia coli are the most common cause of urinary infection.
pathogenic bacteria
have greater virulence, and cause infections (sporadic or epidemic) regardless of host status.
pathogenic bacteria
anaerobic gram-positive rods (e.g. clostridium) cause gangrene.
gram-positive bacteria: staphylococcus aureus (cutaneous bacteria that colonize the skin and nose of both hospital staff and patients) cause a wide variety of lung, bone, heart and bloodstream infections and are frequently resistant to antibiotics beta-haemolytic streptococci are also important.
pathogenic bacteria
gram-negative bacteria: enterobacteriacae (e.g. escherichia coli, proteus, klebsiella, enterobacter, serratia marcescens), may colonize sites when the host defenses are compromised (catheter insertion, bladder catheter, cannula insertion) and cause serious infections (surgical site, lung, bacteraemia, peritoneum infection). they may also be highly resistant.
pathogenic bacteria
gram-negative organisms such as pseudomonas spp. are often isolated in water and damp areas. they may colonize the digestive tract of hospitalized patients.
pathogenic bacteria
selected other bacteria are a unique risk in hospitals. for instance, legionella species may cause pneumonia (sporadic or endemic) through inhalation of aerosols containing contaminated water (air conditioning, showers, therapeutic aerosols).
microorganisms
viruses
viruses
there is the possibility of nosocomial transmission of many viruses, including:
the hepatitis b and c viruses (transfusions, dialysis, injections, endoscopy),
respiratory syncytial virus (rsv),
rotavirus, and enteroviruses (transmitted by hand-to-mouth contact and via the fecal-oral route).
other viruses such as cytomegalovirus, hiv, ebola, influenza viruses, herpes simplex virus, and varicella-zoster virus, may also be transmitted.
microorganisms
parasites and fungi
parasites and fungi
some parasites (e.g. giardia lamblia) are transmitted easily among adults or children.
many fungi and other parasites are opportunistic organisms and cause infections during extended antibiotic treatment and severe immunosuppression (candida albicans, aspergillus spp., cryptococcus neoformans, cryptosporidium). these are a major cause of systemic infections among immunocompromised patients.
parasites and fungi
environmental contamination by airborne organisms such as aspergillus spp. which originate in dust and soil is also a concern, especially during hospital construction.
sarcoptes scabies (scabies) is an ectoparasite which has repeatedly caused outbreaks in health care facilities.

nosocomial infection sites


المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
download lecture file topic