Analysis of data of urine culture isolates of 2013 sent from four laboratories of National Laboratory Based Surveillance of Sri Lanka College of Microbiologists

Abstract

OBJECTVES: To determine the aetioiogical agents of midstream urine cultures with a colony count of > 10 5CFU/ml. To analyse the antimicrobial susceptibility of those isolates. METHOD: The National Laboratory Based Surveillance on Antimicrobial Resistance is a collaborative project of the Ministry of Health and the Sri Lanka College of Microbiologists. At the initial phase decided to analyse midstream urine cultures with a colony count of >105 CFU/ml. The specimens were processed according to the standard protocol specified in the laboratory manual in microbiology. Antibiotic susceptibility tests were performed according to the method established in the centre which is either by CLSI method or by Stake's comparative disk diffusion method. Data of 2013 sent by the participating laboratories were analysed using WHONET software. RESULTS: The data was received from four centres. They were Sri Jayewardenapura General Hospital, Lady Ridgeway those isolates. ATotal of 1175 significant isolates were analysed. The majority were Gram negative enteric organisms, com¬monly known as coiforms, with 922 (78.5%) isolates. The others were Enterococcus species 83 (7%), Candida species 60 (5.1%), Pseudomonas species 38 (3.2%), Acinetobacter species 21 (1.8%), Group B beta-haemolytic Streptococcus 20 (1.7%), coagulase negative Staphylococcus species 10 (0.85%), Streptococcus species 9 (0.8%), Staphylococcus aureus 7 (0.6%), and Staphylococcus saprophyticus 5 (0.4%). The susceptibility of coliforms were 11.6% (92/795) to ampicillin, 71.1% (621/873) to nitrofurantoin, 25.9% (223/ 862) to cephalexin, 46% (392/853) to cefuroxime, 29.4% (255/866) to nalidixic acid, 47.8% (422/883) to cefo-taxime, 92.6% (665/718) to meropenem, 70.3% (601/ 855) to gentamicin, 41.6% (341/819) to amoxicillin-clavulanic acid and 38.4% (318/829) to ciprofloxacin. None of the 13 isolates of Acinetobacter species tested were sensitive to meropenem while only 55% (16/29) of Pseudomonas sp. were sensitive to meropenem. 74% (60/81) of Enterococcus species were sensitive to ampicillin. CONCLUSION: Coliforms constitute the commonest organism causing urinary tract infections (UTI). A high resistance rate was noted in coliforms for broad spectrum antibiotics like cefotaxime and ciprofloxacin. Acinetobacter sp. shows a very high resistance rate even for carbapenems. Ampicillin can be recommended as empirical therapy to treat UTI due to enterococcus species.