The diagnosis of this disease requires the help of related examinations to make a definitive diagnosis, so as to distinguish it from other diseases and avoid misdiagnosis.
1, blood examination
Red blood cell and hemoglobin increased, white blood cell count increased, neutrophils and large mononuclear cells increased. Serum potassium, sodium, chloride and carbonate decreased, blood pH decreased, blood urea nitrogen increased. Before treatment, due to the outward movement of potassium ions from the cells, serum potassium can be within the normal range. When acidosis is corrected, potassium ions move into the cells and hypokalemia appears.
2, urine examination
A small number of patients may have protein, red blood cells and casts in urine.
3, pathogen examination
)1Routine microscopy Mucus and a few red and white blood cells can be seen.
)2Smear staining Smear of feces or early culture is made for Gram staining and microscopic examination, and Gram-negative slightly curved vibrios can be seen.
)3Suspension examination Fresh feces can be made into a drop or dark field microscopy, and it can be seen that the vibrios are active and shuttle-like.
)4Motility test Take water samples or alkaline peptone water enrichment culture from acute patients6hours of surface growth, first make dark field microscopy, observe the motility. If there is a shuttle-like movement, then add 01group polyvalent serum drop, if it is 01group Vibrio cholerae, due to antigen-antibody reaction, then aggregated into lumps, Vibrio motility stops. If added 01group serum after, can not stop the movement, should use 0139serum retest.
)5Enrichment culture All suspected cholera patients' feces, in addition to microscopic examination, should be enriched culture. Feces collection should be before the use of antimicrobial drugs, and should be sent to the laboratory for culture as soon as possible. Enrichment culture medium is generally used pH8.4alkaline peptone water36～37℃ culture6～8hours later, a bacterial film can form on the surface. At this time, further isolation culture should be carried out, and dynamic observation and motility test should be carried out, which will help to improve the detection rate and early diagnosis.
)6Isolation culture Commonly used gentamicin agar plate or alkaline agar plate. The former is a strong selective culture medium36～37℃ culture8～10hours Vibrio cholerae can grow into small colonies. The latter requires culture10～20 hours. Select suspected or typical colonies, use cholera vibrio '0' antigen antiserum for slide agglutination test, if positive, a report can be issued. In recent years, DNA probes for cholera toxin genes have also been used abroad for colony hybridization, which can quickly identify toxigenic 01group Vibrio cholerae.
)7PCR detection The use of PCR technology for rapid diagnosis of cholera has been applied abroad recently. It can distinguish between cholera strains and non-cholera vibrios by identifying the subunit CtxA of Vibrio cholerae toxin gene and the toxin synergistic pilus gene (TcpA) in the PCR product. Then, the different DNA sequences of TcpA gene are used to distinguish between classical biological type and El Tor biological type of Vibrio cholerae.4within hours, it is said that it can detect every ml of alkaline peptone water10below Vibrio cholerae.
)8Differential tests Classical biological type, El Tor biological type and 0139differential diagnosis of cholera vibrio.
4, laboratory examination
)1Hematological and biochemical examination Wbc↑N↑Rbc↑Na+↓k+↓cl-HCO-3↓Bun↑cr↑。
)2)urinalysis microscopy examination A little red blood cells, leukemia, protein, casts.
)3)stool examination:
①Routine examination A little mucus, red blood cells, white blood cells.
②Gram-negative curved vibrios.
③Drop test Active and shuttle-like vibrios.
④Braking test Alkaline peptone water6Hgrowth
⑤Enrichment culture PH8.4alkaline protein peptone water36～37℃6～8H→bacterial membrane→motility braking isolation culture.
⑥ Isolation culture O antigen serum for slide agglutination test
)4)serological immunological examination Antibacterial antibody Antitoxin antibody Anticoagulant
5, routine examination
)1)direct microscopic examination
)2)isolation culture: Directly inoculate the vomit and diarrhea, or first enrich it with alkaline peptone water, and then inoculate it on gentamicin agar and other culture media, it is easy to detect cholera vibrios. The use of fluorescent antibody to detect cholera vibrios in feces can be1～2hours to obtain results.
)3)serological examination: Serum agglutination test can be performed.1～3day and the10～15day each took1times serum, if the2times the antibody titer of serum is higher than that of the1times increased4times or4times or more, has diagnostic reference value.
)4)Braking test - rapid diagnosis: A large number of vibrios are present in the watery stool of acute patients, if the drop test is positive, add cholera polyvalent serum without preservatives (concentration1∶64) the bacteria stop moving within a few minutes, and then coagulate into a block, which is positive.
