Medical Microbiology

Campylobacter,Helicobacter,Spirillum 307

Diagnosis.ToisolateC.jejuniinstoolcultures,mediumsareusedcontaining

selectivesupplements(e.g.,variousanti-infectiveagents).Theculturesare

incubatedfor 48 hoursat 428 Cinamicroaerophilicatmosphere.Identifica-

tionisbasedongrowthrequirementsaswellasdetectionofcatalaseand

oxidase.

C.fetusisreadilyisolatedinmostcases,sinceitisusuallytheonlyorgan-

ismfoundinthematerial(e.g.,blood,cerebrospinalfluid,jointpunctate,pus,

etc.).

Therapy.SevereCampylobacterinfectionsaretreatedwithmacrolidesor4-

quinolones.Resistanceisknowntooccur.

Epidemiologyandprevention.Campylobacterjejuniisamongthemostfre-

quententeritispathogensworldwide.Thebacteriaaretransmittedfroman-

imalstohumansviafoodanddrinkingwater.Directsmearinfectiontrans-

missionamonghumansispossible,especiallyinkindergartenorfamily

groups.Therearenospecificpreventivemeasures.

Helicobacterpylori....................................

Morphologyandculture.H.pyloriarespirallyshaped,Gram-negativerods

withlophotrichousflagellation.Culturesfromstomachbiopsiesaregrownon

enrichedmediumsandselectivemediumsundermicroaerobicconditions

(90%N 2 , 5 %CO 2 ,and 5 %O 2 )forthreetofourdays.Identificationisbased

ondetectionofoxidase,catalase,andurease.

Pathogenesisandclinicalpictures.H.pylorioccursonlyinhumansandis

transmittedbythefecal-oralpathway.Thepathogencolonizesandinfects

thestomachmucosa.Thepathogenicityfactorsincludepronouncedmotility

forefficienttargetcellsearching,adhesiontothesurfaceepithelialcellsofthe

stomach,ureasethatreleasesammoniafromureatofacilitatesurvivalofthe

cellsinahighlyacidicenvironmentandavacuolizingcytotoxin(VacA)that

destroysepithelialcells.

Oncethepathogenhasinfectedthestomachtissuesanacutegastritisre-

sults,thecourseofwhichmayormaynotinvolveovertsymptoms.Potential

sequelaeinclude:

1. MildchronicgastritistypeBthatmaypersistforyearsorevendecades

andisoftenasymptomatic.

2. Duodenalulceration,sometimesgastriculcerationaswell.


3. Chronicatrophicgastritisfromwhichagastricadenocarcinomasome-
   timesdevelops.


4. RarelyBcelllymphomasofthegastricmucosa(MALTomas).

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Kayser, Medical Microbiology © 2005 Thieme