Immunoblot analysis of sera in uncomplicated typhoid fever & with typhoid ileal perforation.

Background & objectives: Ileal perforation is a serious complication of typhoid fever. The exact reasons for the development of perforation in only a few of those infected with Salmonella Typhi is unknown, and it is likely that immunological factors are involved. Therefore we undertook this study to compare the antibody profile in patients with uncomplicated typhoid fever with those having ileal perforation by immunoblotting. Methods: Two groups of patients were included in the study. Group II comprised patients with uncomplicated typhoid fever (n=47), and group I with typhoid ileal perforation (n=33). The flagellar (H), lipopolysaccharide (LPS) and outer membrane protein (OMP) antigens of Salmonella Typhi were extracted and used to test patient sera for antibodies by immunoblotting Results: Immunoblotting using S. Typhi antigens enabled the detection of S. Typhi antibodies in the two groups of patients. A significant difference was seen in the response of these two groups of patients with respect to antibodies to flagella, lipopolysaccharide and outer membrane proteins. Antibodies to flagella were more pronounced among patients with uncomplicated typhoid fever, while anti-OMP antibodies were significantly associated with typhoid ileal perforation. Interpretation & conclusions: A comparison of antibodies in patients with uncomplicated typhoid fever and with ileal perforation revealed the differences in the antibody profiles of the two groups. Our study suggests that the difference in antibody response may in some way play a role in the pathogenesis of typhoid ileal perforation which can also potentially be exploited to develop suitable diagnostic tests.

Evaluation of antibiotic sensitivity pattern in cases of enteric fever in north west Rajasthan.

A total of 50 cases of blood culture proved enteric fever were studied for clinical response to the treatment and compared with in vivo antibiotic sensitivity pattern. Out of 50 Salmonella strains isolated, 37 were S typhi and 13 S paratyphi A. All S typhi isolates were sensitive in vitro to gentamicin and ceftriaxone while sensitivity to ciprofloxacin was 73%, ampicillin 29.7%, chloromphenicol 27%, tetracycline 27% and co-trimoxazole 13.5%. Multidrug resistance (Ampicillin, Chloramphenicol, Cotrimoxazale and Tetracycline) was observed in 62% isolates. All Sparatyphi A isolates were sensitive to all the antibiotics. Clinical response to the antibiotic therapy was as follows: Group I--Ampicillin + Gentamicin: 15 cases, clinical response (CR), 9.1% (S typhi) and 75% (S paratyphi A), mean day of defervescence 5.33 days. Group II--Ciprofloxacin: 29 cases, clinical response 47.6% (S typhi) and 75% (S paratyphi A), mean day of defervescence--5.22 days. Group--III Ceftriaxone: 30 cases, clinical response 100% in all, mean day of defervescence--4.93 days. Thus we observed highly significant discrepancy in antibiotic sensitivity pattern of the isolates and clinical response. Most importantly we observed significantly delayed clinical response to the ceftriaxone. This may be indicative of evolving resistance to ceftriaxone.

Infectious diseases presenting by fever and hepatomegaly

The present study included 51 patients presenting by infectious fever and hepatomegaly. They were admitted to Abbassia and Embaba Fever Hospitals. Patients were subjected to careful history, thorough clinical examination, complete blood picture, urine and stool examination, repeated blood, urine and stool cultures during fever spikes. Slide and tube agglutination test for typhoid and brucella fevers. Mononucleosis diseases were diagnosed by Monospot test, Epstein Barr IgM and G, Cytomegalovirus IgM and G and Toxoplasmosis by indirect fluorescent test. Abdominal U.S., C.T scan and bone marrow examination whenever needed. Fifty one cases included 31[61%] bacterial cases, 12 [23%] mononucleosis cases and 8 [16%] parasitic cases. Thirty one bacterial group included 11[35%] brucella cases, 7 [23%] extrapulmonary tuberculosis, 5 [16%] urinary tract infection, 4 [13%] gram negative septicaemia and 4 [13%] deep seated abscesses. Twelve cases of mononucleosis cases included 6 [50%] infectious mononucleosis, 4 [33%] cytomegalovirus and 2 [17%] toxoplasmosis cases. Eight cases of parasitological group included 4 [50%] malaria cases, 2 [25%] fasciola cases, 1 [12.5%] amoebic liver abscess and 1 [12.5%] due to kala azar. Two [4%] cases died in our series; 1 due to gram negative septicaemia and the other due to kala azar. Cases are discussed and interpreted

Plasma D-dimer levels in patients with typhoid fever.

The plasma levels of D-dimer can be used as a marker of fibrin formation and degradation. Plasma D-dimer levels in the febrile phase of 6 patients with typhoid fever and in the afebrile convalescent phase of 4 of them were measured. D-dimer levels were high in the febrile phase of all 6 patients and within normal range in the afebrile convalescent phase of all 4 patients. Our results indicate that thrombus formation and fibrinolysis may occur in the febrile phase of patients with typhoid fever.

Enteric fever: diagnostic value of clinical features.

OBJECTIVES: to evaluate the diagnostic value of clinical symptoms and signs in enteric fever and to propose a clinical diagnostic criterion. DESIGN: Prospective observational study. SETTING: Kathmandu Medical College, Teaching Hospital, Kathmandu, Nepal. MATERIALS AND METHODS: febrile patients with clinical diagnosis of enteric fever were included in the study with the aim of confirming diagnosis with blood culture, or bone marrow culture and evaluating the diagnostic accuracy of various clinical signs and symptoms. RESULTS: 64% of the clinically diagnosed cases had blood/ bone marrow culture positive. The diagnostic accuracy of the various symptoms and signs excluding fever was between 42%-75.5%. Majority of the symptom and sign did not have very high diagnostic accuracy. Hence a diagnostic criterion was proposed and clinical features with diagnostic accuracy more than 50% were taken into consideration. Major criteria included fever with diagnostic accuracy of 64%, headache with accuracy of 75.5% and relative bradycardia with an accuracy of 66%. Minor criteria included vomiting, diarrhoea, Splenomegaly, chills and abdominal pain /discomfort with diagnostic accuracy of 57%, 55%, 55%, 53% and 51% respectively. Finally after combination of various major and minor criteria a final diagnostic criterion was proposed having an accuracy of 66% and including both major and minor clinical symptom and sign. CONCLUSION: clinical diagnosis of enteric fever will be very helpful in a country like ours. Though none of the clinical symptoms and sign have very high diagnostic accuracy a diagnostic criteria may be helpful. Criteria including both major and minor signs and symptoms would be the most appropriate diagnostic tool as it includes the important abdominal symptoms and signs of enteric fever.

A hospital-based study of bloodstream infections in febrile patients in Dhulikhel Hospital Kathmandu University Teaching Hospital, Nepal.

The etiology of bloodstream infections in febrile patients remain poorly characterized in Nepal. A retrospective study of febrile patients presenting to Dhulikhel Hospital Kathmandu University Teaching Hospital from July 2002 to June 2004 was performed to evaluate the etiology of bloodstream infections and the drug sensitivity patterns of cultured organisms. The medical and laboratory records of all febrile patients with an axillary temperature > or = 38 degrees C who had a blood culture taken (n = 1,774) were retrieved and analyzed. Of these, 122 (6.9%) patients had positive blood cultures, of which 40.1% were age 11 to 20 years. The male to female ratio was 1.7:1. Antibiotics had been taken prior to hospital presentation by 39 (32%) patients. Salmonella enterica serovar Typhi and serovar Paratyphi A were isolated in 50 (41.0%) and 13 (10.7%) cases, respectively. All S. Typhi and S. Paratyphi isolates were susceptible to ceftriaxone, while susceptibility to ciprofloxacin and chloramphenicol was recorded in 94.8% and 94.5% of cases, respectively. Cephalexin and amoxicillin had the lowest rates of susceptibility (64.2% and 54.1%, respectively). Salmonella spp were usually sensitive to chloramphenicol. These findings provide clinicians in this region of Nepal with a better understanding of the spectrum of pathogens causing bloodstream infections and will help guide empiric antibiotic choice.

Bacteria isolated from blood, stool and urine of typhoid patients in a developing country.

Blood, stool and urine samples were collected from 100 patients diagnosed as having typhoid in 5 hospitals in Akwa Ibom State and analyzed for the presence of Salmonella species and other bacteria. Of the 100 blood samples screened, 55 (55%) were positive with the Widal test and 39 (39%) were positive on blood culture. Thirteen (14.1%) out of 92 urine samples were positive for bacterial growth, while 22 (26.8%) of the stool cultures were positive out of the 82 samples screened. Those within the age range 11-20 years old were infected most frequently (33%), followed by the age range 21-30 (19%) and 41-50 (18%) years old. Those in the age range of 0-2 years old (4%) were least infected. Female subjects were more infected than males. The commonest organisms isolated from the blood samples were Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus vulgaris, Streptococcus faecalis, Salmonella paratyphi and Salmonella typhi. S. aureus, S. epidermidis, E. coli, K. aerogenes, S. faecalis, Proteus mirabilis and P. aeruginosa were isolated from urine, while those isolated from stool were S. aureus, E. coli, S. typhi, S. paratyphi, Shigella sp, K. pneumoniae, P. vulgaris, P. aeruginosa and Vibrio cholerae 01. The isolates were sensitive to peflacine, ceftazidine, ciprofloxacin, ceftriaxone, cefotaxime and chloramphenicol. These antibiotics are recommended as the drugs of choice in therapy. The results suggest the existence of symptomless carriers of enteric fever bacilli in the state. This is worrisome, since some of the S. typhi isolates exhibited multiple resistance to commonly used antibiotics.

Comparison of the diagnostic value of local Widal slide test with imported Widal slide test.

A laboratory study comparing the Widal slide agglutination test using local antigens produced by Mekar Jaya Diagnostica (SAT-MJD) with imported antigens (Murex, Abbott) was carried out on 55 sera of typhoid fever patients with positive blood culture and 56 sera of non-typhoid febrile patients. The SAT-MJD antigens consisted of a mixture of 5 different phage-types of S. typhi dominantly found in Indonesia. This study revealed the following results: the diagnostic sensitivity of local and imported antigens was 83.93%, the diagnostic specificity of local antigens was higher than the imported antigens ie 82.14% compared with 64.28%, the diagnostic efficiency of local antigens was 82.88% compared with 73.87% of the imported antigens. The diagnostic positive and negative predictive values of the local antigens were 80.70% and 83.63%, respectively. The imported antigen revealed diagnostic positive and negative predictive values of 69.69% and 80%, respectively. The diagnostic specificity and efficiency of local antigens were significantly different (p < 0.02 and p < 0.05) from the imported antigens. The local antigens have some advantages. There was no variation in within-run and between-day test, compared with a 6.6% variation shown by the imported antigen. The test results obtained 5 minutes after mixing the serum with antigens reduced the possibility of false-positive and false-negative results. The cost of local antigens is lower than the imported antigens. Based on these data, the Widal SAT-MJD has a reliable diagnostic value and can be used in small laboratories, such as primary health centers (Puskesmas).

Role of modified Widal test in the diagnosis of enteric fever.

OBJECTIVES: To evaluate the diagnostic specificity of modified Widal for recent infection in comparison with conventional Widal test. METHOD: Modified widal test was simultaneously done along with conventional Widal test in serum samples obtained from 50 bacteriologically positive cases of Salmonella typhi infection as well as 50 healthy individuals. RESULTS: A four-fold difference in the titres was noticed in the 50 sera of the test group and no charge in the titres of the control group. The early rising O antibodies which are predominantly IgM in nature. These are due to recent infection and are inactivated by 2-mercaptoethanol. On the other hand H is a mixture of IgG and IgM hence IgM portion gets inactivated giving rise to fall in titre. By inactivating IgM antibodies in modified Widal test, the agglutination would be brought about only by specific IgG while in the conventional Widal test agglutination is due to specific IgG and IgM. The difference in the titres indicates specific IgM class of antibodies which is the hallmark of recent infection. CONCLUSION: If conventional Widal test and modified Widal test are simultaneously done, one can be definite about the diagnosis of enteric fever.

Antibody response in typhoid fever in endemic Indonesia and the relevance of serology and culture to diagnosis.

Culture and serology were performed on blood and serum samples collected at or shortly after admission from 473 patients presented with suspected clinical typhoid. Clinical symptoms at first presentation including confusion, hepatomegaly, splenomegaly, abdominal pain, anemia, and gastrointestinal bleeding were non-specific as they were observed even more often in non-typhoid patients. Culture confirmed the diagnosis in 65.3% of the patients with typhoid fever as the final diagnosis. The sensitivity (58%) and specificity (98.1%) of a rapid dipstick assay for the detection of S. typhi-specific immunoglobulin M were somewhat lower than those of culture but higher than those of the Widal test. The dipstick assay thus may well be used in the serodiagnosis of typhoid in situation where culture facilities are not available. Combination of test results of dipstick and culture improved sensitivity to 82.5%. In laboratories that perform blood culture the dipstick assay may be used as a rapid screening tests to facilitate a rapid diagnosis. Sensitivity of the dipstick assay strongly increased with duration of illness and was higher for culture positive than for culture negative patients. Duration of illness, and different pathogen and host factors including dose of infection, pathogenicity and antigenicity, and prior antibiotic use are likely to influence the immune response, therefore the result of the dipstick assay. Duration of illness and presence of S. typhi in the blood are major factors that determine severity of disease.

Typhidot test to detect IgG & IgM antibodies in typhoid fever.

BACKGROUND & OBJECTIVES: As typhoid fever is endemic in India, there is a continuing search for a simple test which can be carried out in small laboratories for an early and rapid diagnosis. We have evaluated the Typhidot test for this purpose. METHODS: The Typhidot test was carried out on coded sera according to the manufacturer's instructions. The test was performed on 30 Widal positive sera, 30 sera from blood culture positive patients, 60 Widal negative sera and 30 samples from patients whose blood culture grew Gram negative bacilli (GNB) other than Salmonella Typhi. RESULTS: Typhidot test was positive for both IgG and IgM in 39 samples, IgM alone in 24 and IgG alone in 2. Of the 30 culture positive samples, 27 were positive by Typhidot. The Typhidot test gave a sensitivity of 100 per cent and specificity of 80 per cent when bacteraemic patients were analysed. INTERPRETATION & CONCLUSION: The Typhidot is easy to perform, and requires no special equipment or training of staff for interpretation of results. It will be a useful complementary test to blood culture and the Widal test in the diagnosis of typhoid fever.

Diagnostic value of dot-enzyme-immunoassay test to detect outer membrane protein antigen in sera of patients with typhoid fever.

Typhoid fever is still an important public health problem in many developing countries especially in tropical parts of the world, as in Indonesia. This problem opens the way for a further study with the aim of finding an alternative serological test with a high degree of reliability for the detection of typhoid fever. Given the above mentioned purpose, a study on the reliability of a laboratory test, the dot-enzyme-immunoassay outer membrane protein (DOT-EIA-OMP) was conducted comprising sera from 207 subjects (44 adult typhoid patients, 43 adult nontyphoid patients and sera from 120 adult healthy individuals serving as controls. The result of the study revealed that the diagnostic sensitivity of the DOT-EIA-OMP test for the detection of typhoid fever can be classified as high (93.16%), the specificity as moderate (76.74%), the efficiency (accuracy), positive predictive value and negative predictive value as high (85.06%, 80.39% and 91.66% respectively). The within run and between days reproducibility of this test was very high (CV=0%). Analysis of data obtained indicated that the DOT-EIA-OMP test was a reliable screening test for the establishment of the diagnosis of typhoid fever in health centers with simple laboratory facilities. The application of this test has to be more contemplated in countries where the cost of laboratory test is a problem.

Blood culture confirmed typhoid fever in a provincial hospital in the Philippines.

Epidemiological features of blood culture confirmed typhoid fever and antibiotic sensitivity of isolated Salmonella typhi strains were investigated in Bohol Province in Central Philippines from where no earlier information of these was avialable. Typhoid fever is endemic elsewhere in the Philippines (eg Metropolitan Manila and surroundings) where also multidrug resistant S. typhi strains have been detected. A laboratory for surveillance of invasive bacterial infections was established in a tertiary care government hospital, in Bohol, Central Philippines, in 1994. Patients with suspected typhoid fever or other serious infection were managed and blood cultures from them were taken according to clinicians' judgment. Blood cultures were processed and the isolated bacteria identified using generally accepted methods. S. typhi and other Salmonella isolates were identified using commercial antisera. Patient data were collected from hospital records. Of a total of 4,699 blood cultures done during a period of 3 3/4 years, 1,530 (32%) were requested for suspected typhoid fever. S. typhi was the most common pathogen isolated from 422 patients (8.9%), followed by S. paratyphi A from 55 patients (1%). Most patients were young adults (43%) and school age children (28%). Male:female ratio was 1.5:1. Among the 422 patients, there were 9 (2%) deaths due to typhoid fever, all with complications. All S. typhi isolates were sensitive to chloramphenicol, cotrimoxazole, and ampicillin. Our observation on blood culture confirmed typhoid fever demonstrates its importance as a major infectious disease in Bohol and gives a sound basis for treatment of typhoid patients and for further clinical and epidemiologic studies of typhoid fever and for following antibiotic sensitivity of S. typhi in Bohol and elsewhere in the Philippines.

Characterization of a phase 1-d epitope on Salmonella typhi flagellin and its role in the serodiagnosis of typhoid fever.

A monoclonal antibody (MAb) directed against Salmonella typhi 52 kDa flagellin protein has been previously produced by our group. In this study, we have demonstrated that the epitope specific to the MAb is unique to phase 1-d. To map the epitope, plasmids encoding different regions of S. typhi flagellin gene were constructed. Analysis of protein produced from each recombinant plasmid indicated that the epitope specific to the MAb resided within amino acids 171-303 (region IV) of S. typhi flagellin protein. The recombinant region IV flagellin was used to develop an ELISA for the detection of IgM antibody to S. typhi in serum. In the hemoculture-positive typhoid group, the developed ELISA was positive in 77 of 92 cases. In patients with non-typhoidal Salmonella, gram-positive and gram-negative bacteria or dengue virus, the ELISA was negative in all 78 cases. Two from 116 healthy control subjects had positive reactions with the assay. The calculated sensitivity, specificity, positive and negative predictive values of the test were 83.7%, 99.0%, 97.5% and 92.8%, respectively. With such high validity together with the requirement of only a single serum specimen and one day for performing the test, the developed ELISA should become a valuable diagnostic test for typhoid fever.