Medical Bacteriology IV PDF

MICROORGANISMSH U M A N R E L AT I O N S / NORMAL FLORA DR. ÖZGE YILMAZLI, PHD M E D I C A L F A C U LT Y, M E D I C A L M I C R O B I O L O G Y D E P T. H O S T - P AT H O G E N I N T E R A C T I O N S When an individual encounter with a microorganism can be cause: A. Colonization (temporary or...

MICROORGANISMSH U M A N R E L AT I O N S / NORMAL FLORA DR. ÖZGE YILMAZLI, PHD M E D I C A L F A C U LT Y, M E D I C A L M I C R O B I O L O G Y D E P T. H O S T - P AT H O G E N I N T E R A C T I O N S When an individual encounter with a microorganism can be cause: A. Colonization (temporary or permanent) B. Infection H O S T - PAT H O G E N I N T E R A C T I O N S • What is the difference between colonization and infection? • Colonization - Host does not react against microorganism • If this microbe causes damage to the host and initiates various pathological processes, infection is mentioned. Opportunistic pathogen and absolute pathogen??? H O S T - PAT H O G E N I N T E R A C T I O N S Absolute Pathogen: Microorganisms indicate infection when present in the host or when isolate from clinical sample. Neisseria gonorrhoeae – Gonorrhea Francisella tularensis – Tularemia Plasmodium sp. – Malaria H O S T - PAT H O G E N I N T E R A C T I O N S • Opportunistic pathogen: • They are microorganisms that do not harm the host as long as they stay in the area they are normally in, but have the potential to cause damage when they pass to sterile body parts. • S. aureus, E. coli, C. albicans… It is a RISK FACTOR, especially for individuals with immune system deficiency.!!! NORMAL FLORA W H AT I S I T ? • Placed in various parts of the human body, • without damaging the host, • even providing some benefits • called normal flora. BASIC PRINCIPLE: IT DOESN’T EXCEED FROM THE BODY REGION WHERE IT IS!!! FAC T O R S A F F E C T I N G D I F F E R E N C E O F N O R M A L FLORA? age diet health condition hormonal status personal hygiene NORMAL FLORA The human body is sterile before birth. We encounter with microorganisms first at birth. After birth, a part of the microorganisms that we encountered by airways, foods or contacts can settle down to various body side NORMAL FLORA The skin of the newborn is first colonized (birth canal) , followed by the oropharynx, gastrointestinal tract, and other mucous membranes. The microbes on that body sites would change rely on the changing status These microbes can be temporary colonized, permanent colonized or can occur an infection ARE THESE M I C R O O R G A N I S M S A L W AY S HARMLESS? • The member of normal flora; • If their place changes, • İf they increase too much, • If they leave their place and invased to steril sites • Can be cause an infection, • So opportunistic pathogens transform to absolute pathogens Hemophilus Veillonella Neisseria Streptokoklar Stafilokoklar PERMANENT FLORA – It is a flora in/on a body side that does not change with age and regenerates in the same amount and in the same place even if it is eliminated by various effects. – They do not cause disease unless they move from their side to another side, the balance between them is not disturbed or the immune system is adequate. It is a community of microbes formed from pathogenic or non-pathogenic microbes in various parts of the body, which disappear after a few hours to a few weeks. – T E M P O R A RY FLORA – When they are eliminated, they do not return. – They do not cause disease as long as they are with permanent flora. THE BENEFITS OF PERMAMENT FLORA It inhibits to place the pathogen species by bacterial interference Skin’s normal flora members produce unsaturated oil acides Intestine bacteria secrete bacteriocin such as colicin and so inhibits the pathogens THE BENEFITS OF PERMAMENT FLORA - 2 They compete with pathogenic bacteria for access to nutrients and to attach to receptors in host tissues (prevent pathogen bacteria’s attaching). They stimulate the immune system to attack to pathogens The permanent members of intestines, secrete Vit. K and take a role with absorbance the nutrients THE HARMS OF PERMANENT FLORA- 1 • If a large amount of bleeding occurs during tooth extraction, members of the normal flora (especially viridans streptococci) can cause infective endocarditis in people with deforming heart valves and artificial heart valves. • Streptococcus pneumoniae, Staphylococcus aureus and many gram-negative bacteria that transport into the lower respiratory tract by aspiration of oral secretion (sneeze, cough, …) can cause infection. THE HARMS OF PERMANENT FLORA- 2 In the case of increasing the pH of stomach and vagen, the normal flora bacteria that are located can increase and cause infections E. coli that found on the perianal skin can infect the urethra and cause urinary tract infection (especially in women). As a result of the use of broad-spectrum antibiotics (very much and unnecessary), bacteria in normal flora can be resistant to this drug and overgrow and occur a danger The member of normal flora bacteria and their location on the body cites İnsan The frequency of gastrointestinal occurrence and sisteminde bulunan densities of the bakteri bacteria in the yoğunluğu ve bulunma gastrointestinal sıklıkları system THE NORMAL FLORA OF THE SKIN • Many microorganisms contact with the skin surface. • Gram (+) - Coagulase negative staphylococcus (CNS), S. aureus, Corynebacterium and Propionibacterium species • Clostridium perfringens is isolated from the skin of approximately 20% of healthy adults. • Candida and Malassezia are also found on the skin surface of moist areas. • Streptococci can colonize temporarily • Acinetobacter baumannii from Gram (-) bacilli can be found in the skin flora. Upper Respiratory Track THE NORMAL FLORA OF R E S P I R AT O RY TRACT • Mouth, • Oropharynx • Nasopharynx T H E N O R M A L F L O R A O F R E S P I R AT O RY TRACT Mouth, Oropharynx and Nasopharynx Consists of 10-100 anaerobic bacteria for each aerobic bacteria The most common anaerobic bacteria are Peptostreptococcus. The most common aerobic bacteria are: Streptococcus, Haemophilus and Neisseria species. Most bacteria that colonize the upper respiratory tract are considered to be avirulent. It is not a problem unless it is transferred to sterile body parts. T H E N O R M A L F L O R A O F R E S P I R AT O RY T R AC T • Potential pathogens such as S. pyogenes, Streptococcus pneumoniae, Staphylococcus aureus, Neisseria meningitidis, Haemophilus influenzae, Moraxella catarrhalis, and Enterobacteriaceae may also be present. • Their isolation from a patient does not always indicate that they are responsible for the disease (remember the colonization-disease difference) THE NORMAL FLORA OF R E S P I R AT O RY T R A C T Lower Airway • The larynx, trachea, bronchioles, and lower airways are usually sterile. • Temporary colonization is associated with upper respiratory secretions!!! • Virulent bacteria that can be found in the oral flora causes to ACUTE LOWER RESPIRATORY INFECTION • C. albicans rarely causes disease • Dimorphic fungi are always associated severe infection, not colonization THE NORMAL FLORA OF EYE • CNS colonize the surface of the eye. • Diseases are typically associated with: S. pneumoniae, S. aureus, H. influenzae, N. gonorrhoeae, Chlamydia trachomatis. THE NORMAL FLORA OF GISS TO M AC H • Remember that the stomach is at an acidic pH due to hydrochloric acid!!! • Therefore, few species are present in it’s normal flora. • Lactic acid bacteria: Lactobacillus and Streptococcus • Acid tolerant bacteria: Helicobacter pylori (gastritis and ulcerative disease) How/when does the stomach flora change? Due to the use of antacid drugs, flora can be change THE NORMAL FLORA OF GIS- SMALL INTESTINE • Colonized by a wide variety of bacteria, fungi and parasites • Most common: anaerobes such as Peptostreptococcus and Prevotella • Salmonella and Campylobacter species, which are common causes of gastroenteritis, can be found in little amounts in asymptomatic carriers!!! THE NORMAL FLORA OF GISLARGE INTESTINE It’s the body region which contains the most amount of microorganisms It’s known that a gram of feces contains more than 1011 bacteria The most commons: Bifidobacterium, Eubacterium, Bacteroides, Enterococcus and Enterobacteriaceae members. THE NORMAL FLORA OF GISLARGE INTESTINE E. coli makes up less than 1% of the intestinal population It’s the most common aerobic bacteria in intraabdominal disseases! Bacteroides fragilis is also found less in large bowel but it’s the most common anaerobic bacteria in intraabdominal disseases! In contrast; Eubacterium and Bifidobacterium are dominant but rarely cause of disseases T H E N O R M A L F L O R A - G E N I T O U R I N A RY SYSTEM Urethra Entrance Urethra dominated by; lactobacillus, streptococci and especially CNS Can be colonized harmfull bacteria such as Enterococcus, Enterobacteriaceae and Candida (a kind of fungi) N. gonorrhoeae and C. trachomatis are the most common in urethritis They can occur asemphtomatic colonization and it’s always accepted significant to identification from clinical samples THE NORMAL FLORAG E N I T O U R I N A RY S Y S T E M Vagina • Newborn babies: colonized with lactobacillus (first 6 weeks) • Maternal estrogen decreases and so Staphylococcus/Streptococcus places • When puberty, again lactobacillus are dominant and also Staphylococcus, Streptococcus, Gardnerella, Mycoplasma and Ureaplasma can be isolated T H E N O R M A L F L O R A - G E N I T O U R I N A RY SYSTEM Vagina The most common reason for vaginitis: Neisseria gonorrhoeae (gonococcus) If the reason isn’t gonococcus: the decrease of lactobacillus’ amount The others: Trichomonas vaginalis, Candida albicans and C. glabrata Although HSV and HPV aren’t considered as normal flora member, they can cause persistent infections!!! T H E N O R M A L F L O R A - G E N I T O U R I N A RY SYSTEM Cervix like urethra • In normal, not colonized with bacteia • N. gonorrhoeae and C. trachomatis are significant reason of cervicitis