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Biomedical subjects

Elizabeth Mathai

Publications and source records attributed to Elizabeth Mathai.

17 recordsLinked to original sources

Evaluation of tests for serological diagnosis of scrub typhus.

Two specific serological tests, a Dot enzyme immunoassay (EIA) and an immunoglobulin (Ig)M enzyme-linked immunosorbent assay (ELISA) using the 56 kDa antigen and the Weil-Felix test were evaluated for diagnosis of scrub typhus. Sensitivity of 100, 86.5 and 43.5% were observed with Dot EIA, IgM ELISA and Weil-Felix test, respectively. False-positive reactions were observed in patients with falciparum malaria, pulmonary tuberculosis, S. viridans septicemia and typhoid fever using Dot EIA and IgM ELISA. Therefore, although Dot EIA and IgM ELISA are useful in the serodiagnosis of scrub typhus, efforts should be made to rule out other febrile illnesses.

Antibodies, Bacterial↗

"Candidatus Rickettsia kellyi," India.

We report the first laboratory-confirmed human infection due to a new rickettsial genotype in India, "Candidatus Rickettsia kellyi," in a 1-year-old boy with fever and maculopapular rash. The diagnosis was made by serologic testing, polymerase chain reaction detection, and immunohistochemical testing of the organism from a skin biopsy specimen.

Anti-Bacterial Agents↗

Some virulence characteristics of uropathogenic Escherichia coli in different patient groups.

BACKGROUND & OBJECTIVE: Uropathogenic Escherichia coli have virulence properties, that are absent in non pathogenic E. coli. The distribution of these markers can vary according to patient populations. Hence, a study was undertaken to describe the presence of virulence factors like Pfimbriae, type 1 fimbriae and haemolysin in E.coli causing urinary infections in three groups of patients. Antibiogram was also recorded to determine differences, if any, between the groups. METHODS: E. coli isolated from three groups of subjects, in counts of >10(5) CFU/ml and in pure growth were tested for mannose resistant haemagglutination (MRHA) to indicate P fimbriae and mannose sensitive haemagglutination (MSHA) to indicate type 1 fimbriae. Haemolysin production and antimicrobial susceptibility patterns were also recorded. RESULTS: Significantly more isolates from antenatal and postnatal women possessed P fimbriae compared to groups with urologic abnormalities (P=0.05). Haemolysin production was also significantly higher (P<0.001) in this group. Greater proportions of isolates from pregnant women were susceptible to commonly used antimicrobials. However, resistance to third generation cephalosporins was present even in these isolates from community infections. INTERPRETATION & CONCLUSION: In patients with urological abnormality, E. coli with lower virulence can cause infections. Isolates from these patients exhibited greater drug resistance. In pregnant women and in community acquired infections, simple antimicrobial drugs like nitrofurantoin might still be useful. However, urgent and stringent policies for antimicrobial use and infection control in hospitals are required in India.

Animals↗

Antimicrobials for the treatment of urinary tract infection in pregnancy: practices in southern India.

PURPOSE: Although urinary tract infection (UTI) in pregnancy is a common medical problem, very little is known about the susceptibility patterns of bacteria causing UTI and the prescription practices for UTI in pregnancy in low-income countries. Studies were, therefore, carried out in southern India to document the susceptibility patterns and to compare these with prescription practices. METHODS: Data on susceptibility patterns of bacteria isolated in significant counts from urine of pregnant women suspected to have urinary infection were collected. Prescribing patterns for these infections were ascertained using a questionnaire. RESULTS: About 90% of E. coli causing UTI is still susceptible to nitrofurantoin, a relatively inexpensive and safe drug. However, less than 25% of doctors used it for treatment of cystitis. Cephalosporins were most commonly used in hospital practice for the treatment of UTI. Amoxycillin was being used widely to treat UTI in pregnancy in spite of high prevalence of resistance. There were wide variations in the duration of therapy and use of prophylaxis. CONCLUSIONS: Our findings indicate an urgent need for proper guidelines, dissemination of information to practitioners and supervision of antimicrobial usage in low income countries like India. Irrational and unnecessary drug use can be expensive and harmful.

Anti-Infective Agents, Urinary↗

Integrons and multidrug resistance among Escherichia coli causing community-acquired urinary tract infection in southern India.

Antimicrobial resistance genes are often clustered in integrons, genetic elements capable of recombination. There is a paucity of data on the prevalence and role of integrons from community-acquired infections in developing countries where resistance to co-trimoxazole is high. We determined the prevalence of integrons among Escherichia coli causing community-acquired urinary tract infection (UTI). Consecutive isolates of E. coli obtained from UTI of pregnant women at the Christian Medical College Hospital, Vellore, India, during 2002 were included. All isolates were tested for susceptibility to 16 antimicrobials using the disc diffusion method and for integrons of classes 1 and 2 by PCR. Of the 58 isolates tested, 28 (48.3%) were resistant to co-trimoxazole and trimethoprim. All these isolates carried integrons. Three additional isolates were sulfonamide resistant but integron negative. Class 1 integrons were present in 21 (36.2%) isolates. Resistance to ampicillin (p=0.000), nalidixic acid (p=0.001), chloramphenicol (p=0.02), tetracycline (p=0.004) and gentamicin (p=0.02) was significantly more common in isolates with integrons. DNA sequencing of two isolates with integrons showed the presence of aadA, dfr1 and dfr7 genes. This study demonstrated that integrons are widely prevalent in India and that they might play a role in multidrug resistance in E. coli from community-acquired UTI.

Community-Acquired Infections↗

Is C-reactive protein level useful in differentiating infected from uninfected neonates among those at risk of infection?

OBJECTIVE: To document effects of intrapartum risk factors for early onset sepsis (EOS) on CRP levels in neonates and to assess the suitability of this test in diagnosing EOS. DESIGN: Cohort study. SETTING: Labour and post natal wards in a tertiary level teaching hospital in India. SUBJECTS: 250 neonates at risk of developing infection. METHODS: CRP levels in cord blood and neonatal blood at 24 hrs were estimated using commercial kits. Babies were observed for signs of sepsis for at least 48 hours. RESULTS: Seven (2.8 Percent) neonates had elevated CRP levels in the cord blood. At 24 hours, 102 (40.8 Percent) babies had elevated levels. Elevated cord CRP levels was significantly associated with rupture of membranes for 24 hours (p =0.04), labour more than 12 hours (p = 0.002), and maternal fever (p = 0.01). At 24 hours, elevated CRP levels were associated with primiparity (p= 0.006), more than three vaginal examinations after membrane rupture (p=0.02), meconium staining of amniotic fluid (p =0.02) and amnioinfusion (p =0.02). Ten (4 Percent) babies developed EOS. The negative predictive value for elevated CRP levels at 24 h was 99 Percent. CONCLUSION: Several intrapartum risk factors for EOS can cause elevation in CRP levels. However, this test may be useful in excluding infection.

C-Reactive Protein↗

Scrub typhus.

Scrub typhus is being increasingly reported in adults in India. It should be considered a strong possibility in all undifferentiated fevers. Two children with this infection are being reported highlighting the wide variation in clinical presentation. Specific tests should be preferred over Weil Felix test wherever possible especially in areas reporting a high incidence of the infection.

Anti-Bacterial Agents↗

Evaluation of topical povidone-iodine in chronic suppurative otitis media.

OBJECTIVES: To evaluate if povidone-iodine (PVP-I) can be used topically in the treatment of chronic suppurative otitis media-tubotympanic disease and to compare it with ciprofloxacin hydrochloride ear drops. DESIGN: Prospective double-blind randomized study. SETTING: Academic tertiary medical center. PATIENTS: Forty patients with chronic suppurative otitis media were randomized into 2 groups. INTERVENTION: One group (19 patients) received 5% PVP-I ear drops, while the other group (21 patients) received 0.3% ciprofloxacin ear drops. Both were administered topically, 3 drops 3 times daily for 10 days. These patients were followed up at weekly intervals for up to 4 weeks after commencing therapy. RESULTS: Clinical improvement at the end of study was 88% in the PVP-I group and 90% in the ciprofloxacin group. The most commonly isolated organism was Pseudomonas aeruginosa. In vitro resistance to ciprofloxacin was seen in 17% of organisms, while no resistance was seen for PVP-I. CONCLUSIONS: To our knowledge, this is the first study to evaluate the efficacy of PVP-I as a topical agent in the treatment of chronic suppurative otitis media. The results show that clinically, topical PVP-I is as effective as topical ciprofloxacin, with a superior advantage of having no in vitro drug resistance. Also, there is an added benefit of reduced cost of therapy.

Administration, Topical↗

Indirect immunofluorescent antibody test for the rapid diagnosis of melioidosis.

Culture is the only reliable method available at present for the diagnosis of melioidosis. Though serological tests have been described, their value in routine diagnosis is controversial. All indirect immunofluorescent assay (IFA) was therefore evaluated to determine its use in the diagnosis of melioidosis. Whole cell antigen prepared from a laboratory isolate of Burkholderia pseudomallei was used to assay IgG and IgM antibodies. Fourteen of the 22 (63.6%) culture proven cases had IgM antibodies while only 10 (45.5%) had IgG antibodies. Negative predictive value of IgM assay was 92 per cent. Positive predictive value was 100 per cent if both IgM and IgG were considered together. The present study done on a limited number of samples suggests that IFA may be useful in routine diagnosis of melioidosis.

Antibodies, Bacterial↗

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.

Antibodies, Bacterial↗

Evaluation of serological tests for the diagnosis of tuberculosis.

To evaluate the use of antibody detection kits in the diagnosis of pulmonary tuberculosis in an endemic area, serum samples from cases (sputum smear positive for AFB) and controls (healthy young adults) were collected and tested using five different kits. Sensitivity, specificity and predictive values were calculated using smear positivity as gold standard. Sensitivity of tests varied from 46% to 68% and the specificity from 68% to 100%. None of the kits evaluated can be used as a single screening test for tuberculosis. However kits with good specificity may be used in conjunction with conventional methods for diagnosis.

Antigens, Bacterial↗