Pathogenic Bacteria 4

Listeria Genus Listeria Ubiquitous named after Joseph Lister Gram (+), rod-shaped, facultative anaerobic, Non-spore forming, motile via peritrichous flagella Catalase (+), Oxidase (-) Weakly β-hemolytic Phylum Firmicutes Class Bacilli Order Bacilliales (Bacillus, Staphylococcus) Family Listeriaceae Ubiquitous Listeriosis . Listeria monocytogenes . Listeria ivanovii . Listeria grayi

Listeria monocytognes Listeria monocytogenes Psychrotrophic : growth at 4°C ~ 37 °C Growth at refrigeration temp. Resistant to pH, heat, salt Lipoteichoic acids in cell wall Resemble LPS of Gram (-) in both structure and function Intracellular parasite Ability to survive and multiply in phagocytic cells monocytes, macrophages, polymorphonuclear leukocytes can become blood-borne (septicemic) Can move within eukaryotic cells can avoid antibody-mediated humoral immunity Penetrate the endothelial layer of the placenta

Listeriosis Listeriosis Zoonosis Most commonly caused by Listeria monocytogenes Listeria ivanovii : mainly in ruminants, rarely in humans Listeria grayi Rare, potentially lethal food-borne illness case-fatality rate of 20~30% Immunocompromised, pregnant women, newborns, the elderly Oral route : ingestion of contaminated food products Penetrate the intestinal tract to cause systemic infections Non-invasive infection : gastroenteritis Invasive infection : central nervous system bacteremia, sepsis

Non-invasiveness infection febrile gastroenteritis (열성 장염) healthy persons who have been severely infected Invasiveness infection Immunocompormised, newborns, the pregnant, the elderly Infections of the central nervous system meningitis, meningoencephalitis (수막뇌염), brain abscess (뇌농양), cerebritis (뇌수염) Bacteremia & Sepsis Influenza-like symptoms usually precede Gastrointestinal symptoms may precede Pregnant woman Intrauterine or cervical infections → spontaneous abortion or stillbirth Transplacental or transvaginal infection (newborns)

Listeriosis in newborns 초기 발현형 감염증 transplacental infection (태반을 통한 감염) granulomatosis infantiseptica (영아 패혈성 육아종증) fatal if not treated immediately 후기 발현형 감염증 transvaginal infection miningitis/meningoencephlitis with septicemia

Diagnosis Treatment Prevention Cold enrichment : psychrotrophic β-hemolytic CAMP test (+) : enhanced hemolysis with S. aureus Treatment Ampicillin (penicillin) alone or with Gentamycin L. monocytogenes : Resistant to cephalosporin Penicillin allergy : Erythromycin Prevention High-risk groups avoid unpasteurized foods (milk products)

Erysipelothrix rhusiopathiae Genus Erysipelothrix Gram (+) : can be mistaken for Gram (-) Type B cell wall the peptide bridge is formed between amino acids at positions 2 and 4 of adjacent peptide side-chains (the vast majority of bacteria, between amino acids at positions 3 and 4) slender rod-shape straight, or slightly curved, or long filamentous singly, in V-shaped pairs, or in short chains aerobic to facultatively anaerobic (microaerophilic) catalase (-) non-spore-forming, non-motile

Erysipelothrix rhusiopathiae Primarily an animal pathogen Erysipelas in animals (단독) pig (swine erysipelas, “diamond skin disease”) turkey, birds, sheep, fish, reptiles Human : Erysipeloid (유단독) : 전염성 피부염 Human erysipelas (단독) : by pyrogenous Streptococcus Treatment & Prevention

Corynebacteria Corynebacteria (Coryne-form bacteria) Coryne : Greek "knotted rod" , “club” Pleomorhic : irregular morphology (다형성) rod-shaped (straight or slightly curved) Snapping fission : V-shaped Gram (+) with high G+C content Corynebacterium, Brevibacterium, Arcanobacterium Micrococcus, Rothia, … Widely distributed in nature Industrially important : amino acids, nucleotides, enzymes bioconversion of steroids, degradation of hydrocarbons

Corynebacterium Human pathogens Genus Corynebacterium Gram (+) distinctive cell wall : mycolyl-AG-peptidoglycan (mAGP) corynemycolic acid, arabinogalactan pleomorphic Catalase (+), aerobic or facultatively anaerobic nonspore-forming, nonmotile Metachromatic granule (이염성 과립) : stored phosphate Industrially important : Corynebacterium glutamicum : Glutamic acid (MSG) Human pathogens Corynebacterium diphtheriae Diphtheroid : nonpathogenic Corynebacterium

Diphtheria Diphtheria Greek ‘diphthera’ leather Corynebacterium diphtheriae virulent & toxigenic strains are lysogenic (β prophage) Acute and contagious infection by direct contact or through the air by contaminated objects. Rare in the developed world due to widespread vaccination Intoxication : diphtheria toxin Laryngeal diphtheria (호흡기 디프테리아) Cutaneous diphtheria (피부 디프테리아)

Laryngeal diphtheria Cutaneous diphtheria Latent period : 2~4 days Begin with a sore throat and fever Airway blockage : swollen throat, barking cough grey or white pseudomembrane (위막) in the throat lymph nodes in the neck may swell barking cough “diphtheritic croup” (가막성 후두염) Complications ; myocarditis (심근염, abnormal heart rate) inflammation of nerves (paralysis), kidney problems bleeding problems due to low blood platelets Cutaneous diphtheria skin, eyes, or genitals

Diphtheria toxin Diphtheria toxin Lysogenic conversion : β phage Exotoxin : A-B toxin : subunits A & B held together by a disulfide bond Highly immunogenic : antitoxin (항독소) Fragment A Inhibition of protein synthesis Inhibition is reversed by high doses of nicotinamide Fragment B Recognition subunit that gains toxin entry into host cell by endocytosis Binding to the cell surface of the B subunit (the less stable) allows the A subunit (the more stable) to penetrate the host cell

Vaccine Vaccine Diphtheria toxoid DPT, DPaT, TdaP : with tetanus & pertussis vaccine Quinvaxem : pentavalent vaccine diphtheria, tetanus, pertussis (whooping cough), hepatitis B, Haemophilus influenzae type b Further doses are recommended every ten years. Moloney test to detect a high degree of sensitivity to diphtheria toxoid intradermal injection of diluted toxoid Previous infection may not prevent against future infection

Treatment Treatment Antitoxin serum (항독소 혈청) Cannot neutralize toxin that is already bound to tissues Serum sickness (혈청병) : horse serum Antibiotic Metronidazole, Erythromycin, Penicillin G Penicillin G/Erythromycin Allergy: rifampin or clindamycin Intubation (삽관) or Tracheotomy (기관절개) open the airway in severe cases

Identification Tellurite Blood Agar Selective medium for Corynebacterium species C. diphtheriae reduces potassium tellurite to tellurium and produce gray-black colored colonies Elek’s test immuno diffusion technique in vitro test for toxigenicity of C. diphtheriae

Pathogenic Corynebacterium Corynebacterium jeikeium Corynebacteirum urealyticum Corynebacterium amycolatum Corynebacterium pseudotuberculosis Corynebacterium ulcerans