Analysis of data of urine culture isolates of 2014 sent from seven laboratories of National Laboratory Based Surveillance of Sri Lanka College of Microbiologists

Abstract

OBJECTIVES: To determine the aetiological agents of midstream urine cultures with a colony count of >105 CFU/ml. To analyse the antimicrobial susceptibility patterns of urine culture isolates of 2014. 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. In this project midstream urine cultures with a colony count of >105 CFU/ml were analysed. 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 2014 sent by the participating laboratories were analysed using WHONET 5.6 software. RESULTS: The data was received from seven centres. They were The National Hospital of Sri Lanka, Sri Jayewardenapura General Hospital, Lady Ridgeway Childrens' Hospital, Faculty of Medicine, Colombo, Faculty of Medicine, Ragama, Faculty of Medicine, Sri Jayewardenapura and North Colombo Teaching Hospital, Ragama. A total of 4441 significant isolates were analysed. The majority were Gram negative enteric organisms, commonly known as conforms, with 3975/4979 (79.8%) isolates. The others were Candida species 408, Enterococcus species 254, Pseudomonas species 194, coagulase negative Staphylococcus species 59, Staphylococcus aureus 36, Acinetobacter species 35 and Group B beta-haemolytic Streptococcus 18. The coliforms from adults who were attending outpatient clinics had 55.2% (112/203) susceptibility to cephalexin andcephradine, 54% (161/298) to amoxycillin/clavulanic acid, 65.1% (278/427) to nitrofurantoin, 48.3% (144/298) to norfloxacin, 63.4% (189/298) to cefotaxime, 97.4% (113/116) to imipenem and 100% (90/90) to meropenem. The adult inward patients had 39.5% (519/1313) susceptibility to cefotaxime, 87.9% (445/506) to meropenem, 62.6% (812/1298) togentamicin and 31.9% (405/1281) to ciprofloxacin. The coliforms from paediatric outpatients had 58.5% (69/118) susceptibility to cephalexin and cephradine, 58.5% (76/130) to amoxycillin/clavulanic acid, 80% (16/20) to nitrofurantoin, 85% (17/20) to cefotaxime and 89.7% (26/29) to meropenem. The paediatric inward patients had 64.6% (53/82) susceptibility to cefotaxime, 90.5% (19/ 21) to meropenem and 80.2% (65/81)togentamicin. CONCLUSION: Coliforms, the commonest organism causing urinary tract infections (UTI), had high resistance rate in in-wardpatients but the resistance was less in outpatients, especially in the paediatric age group.