Microbiology: Neisseria and Moraxella Chapter 17 PDF

12/19/2024 Pathogenicity and Host Range Characteristics of Significant Species Gram Negative Cocci for Neisser...

12/19/2024 Pathogenicity and Host Range Characteristics of Significant Species Gram Negative Cocci for Neisseria and Moraxella of Neisseria, Moraxella, and Kingella Clinically Significant – Neisseria – Moraxella General characteristics: – Gram-negative cocci usually diplococci – Catalase positive – Oxidase positive – Most grow well on sheep and chocolate agar – ID by CTA sugar fermentation patterns – Aerobic – Nonmotile – Nonspore-forming 1 2 3 Cellular Structure of the Cell Neisseria Wall of Pathogenic Neisseria Virulence Factors of Neisseria Many Neisseria spp. are capnophilic Pili Typically, strict aerobes – Five distinct colony types – If alternative electron acceptors (e.g., T1-T2 virulent nitrites) are present, organisms can T3-T5 have no pili grow anaerobically. – Aid in attachment to host tissues Natural habitat – Help prevent phagocytosis – Mucous membranes of respiratory and – Aid in exchange of genetic material urogenital tracts from cell to cell (sex pili) Copyright © 2019 by Elsevier Inc. 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All rights reserved. 4 5 6 1  12/19/2024 Virulence Factors of Neisseria Virulence Factors of Neisseria Virulence Factors of Neisseria Capsule Major outer membrane porin proteins Lipooligosaccharides (LOS) – Prevent phagocytosis – Protein I (Por) – Tissue damage Cell-outer membrane proteins Effective against inflammatory response IgA protease and complement killing – Antigenic variation – Cleaves IgA at mucosal surfaces – Protein II (Opa) – Causes production of useless Facilitate adherence to phagocytic and Receptors for human transferrin antibodies epithelial cells – Allow it to compete for iron Bind to pathogen and prevent binding of – Protein III (Rmp) effective antibodies Block host serum bactericidal action (IgG) 7 8 9 Neisseria meningitidis Neisseria Meningitidis Primary Human Pathogens Found only in humans Epidemiology Neisseria meningitidis (meningococci) Found on the mucosal surfaces – May be present as a commensal inhabitant of Normal flora – Nasopharynx and oropharynx upper respiratory tract of carriers – upper respiratory tract – May become an invasive pathogen Transmitted by close contact – urogenital tracts Neisseria gonorrhea (often called – Carriers – respiratory droplet secretions gonococci) commensal inhabitant – carrier to new host – Always pathogenic when present Only a few colonized hosts develop Both pathogens Infections – endemic meningitis meningococcal disease. – Are fastidious – epidemic meningitis – Highest incidence in infants and – Require enriched media for optimal recovery most often occurs in young adults living in close quarters adolescents – meningococcemia Copyright © 2019 by Elsevier Inc. 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All rights reserved. 10 11 12 2  12/19/2024 Neisseria meningitidis Neisseria meningitidis Neisseria meningitidis Epidemiology Epidemiology Incubation and symptoms Populations at risk of invasive disease Contributors to the spread of Incubation period is 1 to 10 days by colonizing – Asplenic patients meningococcus mucosa. – A small number have bacteria enter bloodstream and – Individuals with complement deficiencies – Crowded living conditions potentially the central nervous system (CNS). – Leads to septicemia and/or meningitis Military recruits College students Characterization of meningitis Populations at risk of serious disease – Frontal headache – stiff neck – Smokers – Confusion – People exposed to smoke Meningococcus disease is – photophobia – Nausea and vomiting uncommon in developed nations. – Individuals with concurrent upper – Sometimes fever – Purulent meningitis respiratory tract viral infection Copyright © 2019 by Elsevier Inc. All rights reserved. Copyright © 2019 by Elsevier Inc. All rights reserved. Copyright © 2019 by Elsevier Inc. All rights reserved. 13 14 15 Neisseria meningitidis Meningococcemia in Infant and Clinical Infections Neisseria meningitidis Hemorrhage in Waterhouse– Friderichsen Syndrome Fulminant disease Death may occur – meningococcal infection that leads to rapidly – 12 to 48 hours from onset. evolving severe septic shock – DIC and septic shock Meningitis – Characterized by abrupt onset of frontal headache, stiff neck, and fever Waterhouse–Friderichsen syndrome – Hemorrhage in the adrenal glands Meningococcemia – bleeding in the adrenal glands – Petechial skin lesions may develop – Purpura, Tachycardia, Hypotension Other complications – May occur with or without meningitis – Arthritis, pericarditis, pneumonia, conjunctivitis, and urethritis Copyright © 2019 by Elsevier Inc. All rights reserved. Copyright © 2019 by Elsevier Inc. All rights reserved. 16 17 18 3  12/19/2024 Neisseria meningitidis Laboratory Diagnosis of Neisseria meningitidis Direct Microscopic Exam Neisseria meningitidis Highly sensitive Gram-stained smears from specimens Specimen – to temperature extremes – To dehydration such as CSF – CSF, blood, or nasopharyngeal swabs Grows on SBA and Chocolate Agar – Meningococci appear as intracellular and or aspirates Grows best in CO2 extracellular gram-negative diplococci. Concentration of CSF can improve – but does not require it. – Concentration of CSF can improve detection on direct exam. detection on direct exam May be encapsulated CTA sugar pattern: At least 1 mL CSF should be centrifuged at 1000xg Culture for 10 minutes. – glucose and maltose positive – Grow on SBA and chocolate agar Sediment is used for direct Gram stain and culture. – lactose and sucrose negative Cytocentrifuge is recommended for best results. – Requires CO2 Identification – See Table 17-5 Copyright © 2019 by Elsevier Inc. All rights reserved. 19 20 21 Direct Gram-Stained Neisseria meningitidis Neisseria meningitidis Smear of CSF Culture and Incubation Identification Note: Presence of intracellular and extracellular Identification is based on gram-negative diplococci. Grow on sheep blood agar (SBA) and chocolate agar – colony morphology, microscopic morphology, and the oxidase test. – For specimens with normal flora, use selective media. Colonies usually grow within 18 to 24 Incubate at 35° C at 3% to 5% CO2 hours. Examine plates daily for 72 hours. Colony morphology Suspected isolates should be handled in – Medium-sized, gray, convex biosafety level-2 (BSL-2) cabinet. – Encapsulated strains are mucoid – Blood underneath colonies tend to have green tinge. Copyright © 2019 by Elsevier Inc. All rights reserved. Copyright © 2019 by Elsevier Inc. All rights reserved. Copyright © 2019 by Elsevier Inc. All rights reserved. 22 23 24 4  12/19/2024 N. meningitidis Colonies Neisseria meningitidis Neisseria meningitidis after 48 Hours Incubation Identification Laboratory-Acquired Left: chocolate (CHOC) agar Oxidase test positive In 2000, two cases of laboratory-acquired Right: sheep blood agar (SBA) Definitive diagnosis can be made via meningococcal disease were reported to – carbohydrate methods (organism uses CDC. glucose and maltose). Both victims were clinical microbiologists – chromogenic enzyme tests. who examined plates, performed Gram – Multi-test assays. stains, sub-cultured or performed slide If testing identifies an isolate as N. agglutination serogrouping on patient meningitides, serotyping should be done. isolates on the open bench. – Molecular techniques – CDC recommendations to prevent future such MALDI-TOF MS disease—work under BSL-2 cabinet Copyright © 2015 by Saunders, an imprint of Elsevier Inc. Copyright © 2019 by Elsevier Inc. All rights reserved. Copyright © 2019 by Elsevier Inc. All rights reserved. Copyright © 2019 by Elsevier Inc. All rights reserved. 25 26 27 Neisseria meningitidis Neisseria meningitidis Neisseria meningitidis Treatment Vaccine Vaccine Penicillin for confirmed meningitis Two quadrivalent polysaccharide-protein Vaccinations are recommended for – Chloramphenicol for penicillin allergic conjugated vaccines are available for some military recruits. Third-generation cephalosporins for subtypes(only for A, C, Y, and W-135). asplenic patients meningococcemia – older than 2 years of age. For close contacts of patients (infected people) In 2014 and 2015, two vaccines were approved laboratory scientists – Chemoprophylaxis with rifampin, ciprofloxacin, or for serogroup B. – who work with N. meningitidis. sulfonamide – Vaccines are conjugated vaccines of proteins from – Use Azithromycin if ciprofloxacin is resistant. other bacteria bound to N. meningitides group B outer for some specific serogroups Routine susceptibility testing is not membrane proteins. poorly immunogenic recommended. – Recommended for used for managing epidemics or limit young adults aged 16 to 23 years old. Chemoprophylaxis not recommended for outbreaks – Provides short-term protection against 91% of US of asymptomatic carriers meningococcal B strains and is administered as a 2 or 3 Travelers to endemic areas dose series Copyright © 2019 by Elsevier Inc. All rights reserved. Copyright © 2019 by Elsevier Inc. All rights reserved. Copyright © 2019 by Elsevier Inc. All rights reserved. 28 29 30 5  12/19/2024 Neisseria gonorrhoeae Neisseria gonorrhoeae Neisseria gonorrhoeae aka gonococcus or GC Infections Infections in women: – Most commonly transmitted by sexual – Endocervix most common site of infection Agent of gonorrhea contact Cervical/vaginal discharge Primary reservoir dysuria – Asymptomatic carriers lower abdominal pain Humans are the only natural Asymptomatic carriers vaginal bleeding host – most common source. – Untreated infections Incubation period can lead to PID – 2-7 day Sterility Gonorrhea Infections in men: Ectopic pregnancy – Acute urethritis Perihepatitis (Fitz-Hugh-Curtis – columnar and transitional syndrome) – Prostatitis – asymptomatic epithelium. – Epididymitis May be up to 50% of cases Acute pyogenic infection of – Asymptomatic infections are unc ommon Disseminated infections: the 3-5% – Purulent arthritis – Urogenital tract – Septicemia – Pharynx – Fever – Conjunctiva of the eye – rash on extremities 31 32 33 Neisseria gonorrhoeae Neisseria gonorrhoeae Neisseria gonorrhoeae Blood-borne Clinical Infections in Clinical Infections in d iBsol soed-mborinneadtsi isoenmination(