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Understanding Enterobacteria: Identification, Detection, and Treatment

Learn about Enterobacteria, including key antigens, virulence factors, laboratory detection methods, and therapeutic options. Explore the different pathogenic strains within the Enterobacteria family and their specific characteristics.

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Understanding Enterobacteria: Identification, Detection, and Treatment

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  1. Enterobacteria G-rods, facultative anaerobe, O (body), H (flagellate), K (fimbrial) antigens, many arecomensalsinintestine but some are potential pathogens Factors of virulence: Endotoxin, fimbrias, exotoxins Lab. detection:cultivationonBA/Endo, chromogennous media, biochemistry (enterotest), antigennous analysis, in addition to intestinal infections we also do ATB susceptibility testing Transport: oftenfecal-oral Therapy: cefalosporins, fluoroquinolons, aminopenicillins, carbapenems etc.

  2. Yersinia Y. pestis immobile Causes 3 forms of pest: 1. bubonic pest (hit only regional lymphatic nodes) Transducer: flea Xenopsilla cheopis, 2. pulmonary form - aspiration of the dust by ill-nursing 3. septic form Y. enterocolitica apendicitis-like syndrome, growth on CIN medium in cold, urease+

  3. Salmonella sp. Salmonellatyphi septicfever andheadache, pink spotson the skin, alive ingallblader Detection:direct – from blood andurine, agglutination, indirect – Widalreactionproof of antibodies Therapy:fluoroquinolons, chloramphenicol, cholecystectomy in vectorsisused Primaryzoopathogennoussalmonellas (S. enteritidisetc...) Biochemistry: productionof H2S (hydrogen sulfide), disunitemannitol Cultivationanddetection: lactosis negative coloniesonENDO, on XLD/MAL/DC - blackcolonies, agglutination, multiply in selenitebroth Pathogenicity: diarrhoea Source: domesticbirds, eggs, saladcream, ice... Therapy: ATB are not indicated, we use sauerkraut, yogurt, keephygienerules

  4. Genus Shigella (Sh. flexneri, sonnei, boydii, dysenteriae) immobile, causeswatery diarrhoea withtenesm, blood in stool Epidemiesfromwatersources – camps, social care institutes Therapy:fluids Escherichia coli Saprophyte in intestine, patogennous are only these, withspecificfactorsof virulence, these are dividedintogroups: EPEC (enteropatogennous) - diarrhoea in children do 2 let, serotypeslike O55, O126 // known as Pharaohrevenge ETEC (enterotoxigennous) – cause travel diarrhoea EIEC (enteroinvazive) – bloody diarrhoea VTEC/EHEC (verotoxigennous, enterohemoragic) – intestinalbleeding, hemolytical-uremic syndrom. Most commonserotype O157 Outofintestinecan cause urinarytractinfections, woundinfectionsetc. Diagnostic: growth on ENDO -typical metal shine, lactose positive, formindol,pyr test negative, agglutinationisneeded in specialcases Therapy:susceptible to many antibioticsincludingampicillin

  5. GenusEnterobacterGenusKlebsiella Mobile immobile resistance to ampi, res. only to ampicillin cefalosporins I. and II. gen. Urease - urease + Pathogenicity: similar:urinary infections, pulmonary infections, sepsis, ability to formextended spectrum β-lactamase (ESBL), therapy:carbapenems only

  6. Serratia marcescens Nosocomial infections, heteroresistance to colistin Genus Proteus Cultivation: crawl in waves on medium - Rouss phenomenon Biochemistry active, smell, urease +, in additon to P. mirabilis form indol Pathogenicity: wound/urinary infections Therapy: primary resistance to nitrofurantoin and colistin Genus Citrobacter looks like salmonella, can form black colonies on XLD, ONP+ and PYR test+

  7. G- micro-aerophile rods Campylobacter jejuni Helicobacter pylori Microscopy:G-bent rods G-curved rods Cultivation: spec. medium with carbon 2 media: Thayer-Martin medium + control medium Grey colonies with metal shine little transparent colonies like haemophillus cultivation via 42˚C 48 hours 5 day cultivation Biochemistry + resistance: oxidase, catalase oxidase, catalase, urease Resistant to cefalotin S to cefalotin Susceptibility to nalidix acid R to nalidix acid Patogenicity: diarrhoea gastritis to gastric ulcer Therapy: without therapy/hard infections - macrolides 3combin. amoxic.+metronidazol+bismut amoxicillin+claritromycin+omeprazol H. pylori

  8. Genus Vibrio Live in water, bettergrow i presence ofNaCl (halophilic) +growalso in alcalic pH, susceptible to vibriostaticcompound, after drop ofdeochycholatesodiumformstring (string test), oxidase V. cholerae Microscopy:G-curved rods, withflagellum Due to O antigen we distinguish 155 serotypes. Most common are O1 (El Tor andclassictype), O139, non O1/O139 - NAG (nonagglutinable) vibria Pathogenicity: diarrhoea lookinglike rice soup, vomitting Therapy: rehydratation + chloramphenicol Diagnostic: cultivation on TCBS agar - greencolonies, membraneinalcalic pepton water, detection of serotypewith help ofthe agglutination Other vibria Cause diarrhoea, woundinfections Aeromonas negative string test Not susceptible tovibriostaticcompound Cause diarrhoea, on TCŽS formyellowcolonies

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