Antibiogram of gram-negative bacilli (Gnb) isolated from urinary tract infection (uti)-with a special reference to detection of amp c β-lactamase producing gram-negative bacilli causing uti

Abstract

Introduction: Urinary tract infection (UTI) remains one of the most common causes of morbidity in the general population. Wide variety of organisms are implicated in its aetiology, gram-negative bacilli (GNB)being most common. UTI is treated with a variety of broad-spectrum antibiotics. Resistance to antibiotics is increasing nowadays. Gram-negative bacilli confer resistance to βlactam antibiotics by producing enzymes like Extended-spectrum β – lactamase and Amp C β – lactamase. The present study was carried out with the aim and objectives to isolate and identify GNB causing UTI and to prepare antibiogram of these isolates. The study also includes to find out the prevalence of Amp C β – lactamase producing GNB causing UTI. Materials and Methods: The urine samples obtained from patients having suspected urinary tract infection were processed to isolate and identify the causative organism. Antibiotic susceptibility testing was done by Kirby Bauer Disk Diffusion method for gram-negative urinary isolates in patients with significant bacteriuria. Clinical Laboratory Standards Institute (CLSI) guidelines were followed during the interpretation of results. GNB showing resistance to 3rd generation cephalosporins and resistance to cefoxitin were subjected to Amp C Disk Test to detect Amp C β – lactamase producing GNB. Minimum Inhibitory Concentration (MIC) for ceftazidime was tested for these isolates. Results: Total of 288 samples from patients with suspected UTI were processed.214 samples were culture positive. Out of which 167 samples showed significant bacteriuria (78.03%). Gram-negative bacilli isolated were 74.85%. All GNB showed reduced susceptibility to 3rd generation cephalosporins. They were susceptible to amikacin, nitrofurantoin, imipenem, meropenem. Pseudomonas isolates showed resistance to imipenem and meropenem. Prevalence of Amp C β – lactamase producing GNB was 21.6%. Conclusion: Gram-negative bacilli producing UTI were 74.85%. These isolates showed resistance to 3rd generation cephalosporins. They were susceptible to amikacin, nitrofurantoin, imipenem, meropenem. Pseudomonas isolates were resistant to imipenem and meropenem. Prevalence of Amp C β – lactamase producing GNB was 21.6%.