Efficacy of Urine Dipstick Test in Diagnosing Urinary Tract Infection and Detection of the blaCTX-M Gene among ESBL-Producing Escherichia coli

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Efficacy of Urine Dipstick Test in Diagnosing Urinary Tract Infection and Detection of the blaCTX-M Gene among ESBL-Producing Escherichia coli

 

Rubina Gurung1, Sanjib Adhikari1, Nabaraj Adhikari1, Sanjeep Sapkota2, Jid Chani Rana3, Binod Dhungel1, Upendra Thapa Shrestha1, Megha Raj Banjara1, Prakash Ghimire1 and Komal Raj Rijal1*

 

1Central Department of Microbiology, Tribhuvan University, Kirtipur 44600, Kathmandu, Nepal;

2Department of Microbiology, Birendra Multiple Campus, Tribhuvan University, Bharatpur 44200, Chitwan, Nepal;

3Department of Microbiology, Bharatpur Hospital, Bharatpur 44200, Chitwan, Nepal;

 

* Correspondence: rijalkomal@gmail.com or komal.rijal@cdmi.tu.edu.np

 

ABSTRACT

 

A urine dipstick test used for prompt diagnosis of urinary tract infection (UTI) is a rapid and cost-effective method. The main objective of this study was to compare the efficacy of the urine dipstick test with culture methods in screening for UTIs along with the detection of the blaCTX-M gene in extended spectrum-lactamase (ESBL)-producing Escherichia coli. A total of 217 mid-stream urine samples were collected from UTI-suspected patients attending Bharatpur Hospital, Chitwan, and tested by dipstick test strip (COMBI-10SL, Germany) prior to the culture. E. coli isolates were identified by standard microbiological procedures and subjected to antimicrobial susceptibility testing by Kirby Bauer disc diffusion method following CLSI guideline. Primary screening of ESBLproducing E. coli isolates was conducted using ceftriaxone, cefotaxime and ceftazidime discs and phenotypically confirmed by combined disk diffusion test. Plasmid DNA of ESBL-producing strains was extracted by phenol-chloroform method and subjected to PCR for detection of the blaCTX-M gene. Out of 217 urine samples, 48 (22.12%) showed significant bacteriuria. Among 46 (21.20%) Gram negative bacteria recovered, the predominant one was E. coli 37 (77.08%) of which 33 (89.19%) were multidrug resistant (MDR). E. coli isolates showed a higher degree of resistance towards cefazolin (62.16%) while 81.08% of the isolates were sensitive towards amikacin followed by nitrofurantoin (70.27%). Among 14 (37.84%) phenotypically confirmed ESBL isolates, only eight (21.62%) isolates carried the blaCTX-M gene. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of urine dipstick test were 43.75%, 77.51%, 35.59% and 82.91%, respectively. Besides, the use of dipstick test strip for screening UTI was associated with many false positive and negative results as compared to the gold standard culture method. Hence, dipstick nitrite test alone should not be used as sole method for screening UTIs.

 

Keywords: Escherichia coli; ESBL; sensitivity; specificity; PPV; NPV; blaCTX-M

 

Citation: Gurung, R.; Adhikari, S.; Adhikari, N.; Sapkota, S.; Rana, J.C.; Dhungel, B.; Thapa Shrestha, U.; Banjara, M.R.; Ghimire, P.; Rijal, K.R. Efficacy of Urine Dipstick Test in Diagnosing Urinary Tract Infection and Detection of the blaCTX-MGene among ESBL-Producing Escherichia coli. Diseases 2021, 9, 59. https://doi.org/10.3390/diseases9030059

 

Academic Editor: St Patrick Reid

Received: 26 June 2021

Accepted: 26 August 2021

Published: 27 August 2021

 

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Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/

 

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