Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
GIT-block Microbiology Lab. Dr./ Tamer Ata Contents • • • • Bacterial enteritis Fungal intoxication Parasitological slides Blood culture Bacterial enteritis Bacterial enteritis Mostly Gram negative bacilli including 1. Vibrio spp. 2. Shigella spp. 3. Salmonella spp. (food poisoning & enteritis) 4. E. coli (EHEC O157/H7 & EPEC & ETEC& EIEC) 5. Campylobacter SPP. Lab. Diagnosis • Specimen: stool • CULTURE of specimen for isolation of the pathogen: On selective and differential media as XLD= Xylose Lysine Deoxycolate Agar • Identification of the isolated organism • Serological • Typing in outbreaks to trace source of infection Culture media XLD media • Selective media for enteric Gram negative bacilli • Also differential media as can differentiate lactose fermenters (LF) from non lactose fermenters (NLF) • LF → yellow colonies • NLF → pink colonies + black color (H2S production) LF colonies on XLD media Possibility of the organism? E. coli Other test to confirm diagnosis? • Biochemical reactions as API 20 E • Serological characterization? To differentiate it from flora NLF colonies on XLD media Possibility of the organism? Shigella spp. Further identification between the spp. by? 1. Biochemical reactions as API 20 E 2. Serological characterization Disease caused: Bacillary dysentery NLF colonies with H2S production on XLD media Possibility of the organism? • Salmonella spp. Further identification between the spp. by? 1. Biochemical reactions as API 20 E 2. Serological characterization. Disease caused: infective enteritis or enteric fever API 20 E PRINCIPLE? • Bacteria suspension placed in the small tubules of the strip • Each one is a lyophilized biochemical reaction • After incubation it gives colors which converted into numbers • From index we can identify the spp. Bacteria by its number Uses: identification of bacterial spp. Also used in typing Vibrio colonies on TCBS media • Possible bacteria: V. cholera • Confirmatory tests: 1. Serological typing 2. PCR 3. Biochemical reaction as +ve cholera red reaction • Disease caused by the organism: cholera • Type of the media: selective media Vibrio colonies on TCBS media Fungal intoxication Aspergillus spp. on Sabouraud’s dextrose agar (SDA) • Suspected toxin: Ochratoxin • Pathological effect of the toxin: nephrotoxic, immunosuppressive, carcinogenic and neurotoxic Aspergillus by lactophenol cotton blue Parasitology Head of Taenia worm • Classification: Cestodes T. saginata (beef tape worm) • mode of infection: ingestion of larva in undercooked meat beef) • Disease : asymptomatic or diarrhea • diagnosis: detect egg in stool • treatment: praziquantel Enterobius vermicularis (pin worm) Enterobius vermicularis (pin worm) • • • • Classification: Nematodes Infective stage: D shaped egg Diagnostic stage: egg Sensitive method for diagnosis: adhesive anal tape technique. • Habitat: caecum or large intestine • Clinically: nocturnal anal itching • Treatment: Mebendazole Ascaris larva Ascaris larva • Classification: NEMATODES • Habitat: small intestine and bile ducts • Clinically: intestinal obstruction, biliary obstruction • Infective stage: egg • Diagnostic stage: egg • Treatment: Mebendazole Blood culture Blood culture • Uses: Diagnose of 1. 2. 3. 4. enteric fever in the first week Brucellosis or Malta fever Bacteremia and septicemia Infective endocarditis • specimen: 5-10 cc venous blood under aseptic technique (at least 2 or 3 specimen taken from different limb) Blood culture Principle: 1. Blood added to 50 cc nutrient broth (ratio 1/10 or 1/5) then incubated at 37°C for 7 days 2. Each day the culture is examined for signs of bacterial growth 3. If signs of bacterial growth are detected sub-culture, (or daily subculture), on blood, chocolate and Mac-Conkey agar were done to isolate and identify the organism 4. If 7 days pass without isolation of any growth, reported as negative sample Blood culture Signs of bacterial growth as • Hemolysis • Turbidity • Surface pellicle Advantage of big volume • More nutrition for the organism • Dilute antibiotic if the patient receiving antibiotic THANKS