Non-Fermenting Gram Negative Bacteria as Uropathogens in Causing Urinary Tract Infection and its Antimicrobial Susceptibility Pattern at A Tertiary Care Centre of South India

Anupam Berwal,K.L Shobha,Raghav Chawla,Asem Ali Ashraf,Sonali Sonali,Bhawna Sharma,Rohit Gupta,Kriti Gupta,Abishek Kumar B,Prerna Aggarwal

doi:10.22207/jpam.14.3.43

Abstract

Non fermenting gram-negative bacilli (NFGNB) are recently striving as uropathogens. The present study was conducted to isolate the common species of bacteria in NFGNB causing urinary tract infection (UTI) and its correlation with comorbid conditions and to study the antibacterial susceptibility pattern. This retrospective study was done at the diagnostic Microbiology laboratory of a tertiary care hospital. Urine samples were collected for the period of six months. These samples were plated on blood agar and MacConkey agar and incubated at 37°C for 18–24 hr under aerobic conditions. Identification of NFGNB was done by Gram staining and MALDI-TOF (Matrix- Assisted Laser Desorption/ Ionization- Time of Flight, Biomerieux- Diagnostics). Antibiotic sensitivity testing was done by Vitek® 2 system (Biomerieux- Diagnostics) using N 281 card. Data was analyzed using SPSS IBM version 16. Out of the total 16,413 non repetitive urine samples that were received in the laboratory, 318 had significant bacteriuria. NFGNB were identified in 108 (33.9%) of all the urine samples with significant bacteriuria. Prevalence of non-fermenters in our study was 0.6%. NFGNB were more frequently isolated in the females and also in the age group of more than 50 years. Eighty five (78.70%) had comorbid conditions. P. aeruginosa and A. baumannii were the most common organism isolated among NFGNB. Pseudomonas aeruginosa isolates showed high susceptibility to imipenem (80.2%) and amikacin (66.6%). NFGNB although seen frequently in females and in age group of 50 years and above, clinical correlation with comorbid condition is essential to label it as uropathogens. Amikacin or imipenem may be the empirical drug of choice.

Highlights

Non fermenting gram-negative bacilli (NFGNB) are gram negative bacilli that can survive and grow in oxygenated environment and are incapable of fermenting glucose & utilizing it as a sole source of energy[1]
NFGNB were isolated in 108 (33.9%) the urine samples with significant bacteriuria
It was found that all the samples that grew NFGNB were from the patients who were admitted in the hospital

Summary

Introduction

Non fermenting gram-negative bacilli (NFGNB) are gram negative bacilli that can survive and grow in oxygenated environment and are incapable of fermenting glucose & utilizing it as a sole source of energy[1]. Hospital surroundings and intestines of human beings provide a niche for them to survive as saprophytes[2,3]. They may pose a serious problem by causing infections associated with indwelling medical devices like urinary catheter or ventilator. High degree of resistance to various biocides are present in these isolates. P. aeruginosa and A. baumannii are the most frequently isolated non-fermenters[6]

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Results

Conclusion