Browsing by Author "Lalloo, D.C."

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    Antibiotic use and antimicrobial activity in urine of febrile patients
    (Sri Lanka Medical Association, 2007) Wijesuriya, M.T.W.; Bailey, M.S.; Premaratna, R.; Wuthiekanun, V.; Peacock, S.J.; Lalloo, D.C.; de Silva, H.J.
    OBJECTIVES: Prior antibiotic use may decrease sensitivity of bacterial cultures leading to diagnostic difficulties. Our objectives were to detect antimicrobial activity in urine of patients presenting with fever and to correlate urine antimicrobial activity to blood culture results and antibiotic history. DESIGN, SETTING AND METHODS: This is carried out as part of a fever study during a one-year period. A sample of urine is collected within 24 hours of admission before antibiotics from consenting, febrile (>38°C) patients. Antimicrobial activity in urine is detected by applying urine-soaked discs onto agar plates inoculated with standard bacterial cultures. All patients have extensive microbiological investigations including high-quality blood cultures (with leptospiral cultures), dengue and other viral serology. RESULTS: From 117 patients recruited in 4 months, 76(65%) reported taking medication for their fever, of which 40(53%) said this was an antibiotic. Standard E. coli and S. pyogenes cultures detected antimicrobial activity in 32(27%) and 25(21%) of urines respectively. Using both strains together increased detection to 39%. Only 19(47.5%) reporting prior antibiotic use had urine antimicrobial activity. From 41 denying prior medication, 8(20%) had urine antimicrobial activity. From 43 suspected of having bacterial infection, 46% had urine antimicrobial activity. No patients with positive bacterial cultures had detectable urine antimicrobial activity, whereas 53% of negative bacterial cultures had positive urine antimicrobial activity. CONCLUSIONS: Clinical history is unreliable in assessing prior antibiotic use. Detectable urine antimicrobial activity may lead to negative blood culture results. Therefore in suspected bacterial infections, an assessment of urine antimicrobial activity along with microbiological cultures will reduce the diagnostic dilemma.
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    Identifying the offending species in snakebite: a clinical score for use in community based epidemiological surveys
    (Sri Lanka Medical Association, 2004) Pathmeswaran, A.; Fonseka, M.M.D.; Kasturiratne, A.; Nandasena, S.; Gnanatilaka, G.K.; Gunaratne, L.; de Silva, A.P.; Lalloo, D.C.; de Silva, H.J.
    INTRODUCTION: Hospital data on snakebite fails to account for victims who do not reach hospital or who seek alternative treatment. In community surveys, identification of biting species is very difficult because the offending snake may sometimes not even be seen, is infrequently captured or killed, and antigen detection cannot be used in this setting. OBJECTIVE: To develop and validate a clinical score to identify biting species. METHODS: We identified 10 features relating to bites of the 6 venomous snakes in Sri Lanka (3 relating to circumstances of a bite and 7 clinical features of envenoming). Based on these, we developed a score applying different weightings to individual features depending on the species of snake. We then constructed 60 artificiaLdata sets containing different clinical scenarios, typical and atypical, for bites of a particular species. They were used to make adjustments to the score and determine cut-off values for identification (total ≥60/100 + difference of ≥5/100 from second highest score). The score was prospectively validated on 134 cases of snakebite with definite species identification, six months after the incident. RESULTS: Data were available from 25 cobra bites, 32 hump-nosed viper bites, 27 krait bites, 30 Russel's viper bites and 20 saw-scaled viper bites. Sensitivity/specificity of the score were: cobra 76/99, kraits 85/99, RV 70/99, HNV 97/83, SSV 100/83. 114 (85%) cases were correctly identified. 17 (12.7%) were misidentified, and 3 (2.3%) could not be identified. Conclusions: This score identifies the offending snake species with reasonable accuracy, and may be suitable for use in epidemiologicai surveys.