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Purpose Urinary tract infection is one of the most prevalent disease affecting people from all age groups. For its diagnosis, conventional culture and antibiotic susceptibility is the gold standard. However, its major limitation is that the results take minimum of 24 h and antibiotic susceptibility is available after 48 h. Automated culture methods having comparable sensitivity and specificity as compared to conventional culture should be evaluated for routine diagnostics. With this aim we evaluated the diagnostic accuracy of automated urine culture method HB&L uroquattro by comparing with the gold standard conventional culture method. Materials and methods A total of 1220 urine samples were included in the study. Semi-quantitative urine culture was performed using standard methods on cysteine lactose electrolyte deficient medium. For the automated culture, HB&L Uroquattro (Alifax, Polverara, PD, Italy), standard guidelines given in the manual of the instrument were followed . Diagnostic performance in terms of sensitivity, specificity, positive and negative likelihood ratios, positive and negative predictive values were calculated. Results Based on the final interpretation of conventional culture for the total 1220 samples, 26 samples (2.1%) showed major non-concordance as they were identified as sterile by HB&L but had significant growth by conventional culture and 19.9% showed minor non-concordance. At 100–999 colony forming unit/ml, HB&L has high negative predictive value i.e. 96.6% with 95% CI (95.2%–97.6%) and sensitivity i.e. 92.66% with 95% CI of (89.42%–95.15%). Conclusion The HB&L Uroquattro seems to be a reliable instrument to obtain urine microbiological results in a timely manner. This technique can give presumptive report to the clinician within 5 h only for initiation of empirical antibiotics in cases of positive results. Introduction Urinary tract infection (UTI) is one of the most prevalent disease affecting people from all age groups, including neonate and geriatric age groups [1]. Though UTI affects both genders, women in the age group 15–44 are more prone to this infection [2]. Approximately 40% of women and 12% of men experience symptomatic UTI at some points in their lives [3]. Thus, urine samples constitute a major burden of the specimens processed in clinical microbiology laboratories and diagnosis and management of urinary tract infection poses a significant challenge to the healthcare system of any nation. For the diagnosis of UTI, conventional culture and antibiotic susceptibility is the gold standard. However, its major limitation is that the results take minimum of 24 h and antibiotic susceptibility is available after 48 h. Moreover, the percentage of positivity in urine samples varies from 20 to 30% in different settings and the rest of the samples are sterile [4]. The assays used for rapid diagnosis of UTI are based on direct detection of bacteria and leukocytes by microscopic observation or automated instrumentation, or on the detection of metabolites related to the presence of leukocytes (i.e., esterase) or bacteria (i.e., nitrites) [5,6]. Automated culture methods having comparable sensitivity and specificity as compared to conventional culture should be evaluated for routine diagnostics. These methods should give rapid results without compromising the diagnostic efficacy. Different types of automated culture methods based on bacterial kinetics in liquid media have also been developed [[7], [8], [9], [10], [11]]. One such system is Alifax HB&L uroquattro (Alifax, Italy) which is an automated system used for screening of the urine samples by rapid quantitative bacterial culture estimation [12,13]. It monitors the growth phases of bacteria from the inoculum step into specific culture broths providing real time growth curves and quantitative bacterial count results in colony forming unit (CFU)/ml. It rules out the negative samples within 3–4 h, hence helping clinicians to rule out the possibility of UTI and shift their attention to finding an alternative aetiology. With this aim only, the present study evaluated the diagnostic accuracy of the automated urine culture method HB&L uroquattro (UQ) by comparing with the gold standard conventional culture method. We also investigated whether bacterial yields of UQ vials with positive growth can be used in identification. Section snippets Material and methods It is a prospective observational study in which a total of 1220 urine samples (midstream clean catch urine) collected in a sterile container which were received in the enteric laboratory of Postgraduate Institute of Medical Education and Research (PGIMER) as a part of routine diagnostic from the period of June 1, 2021 to July 1, 2021 from outpatients and inpatients with symptoms suggestive of UTIs were included. The samples were transported in cold chain and processed immediately first for Results Out of the total 1220 urine samples processed, 700 samples were from the inpatient department and 520 from the outpatient department of PGIMER Chandigarh. Out of these samples, on conventional culture, 356 (29.1%) were scored as positive cultures based on counts and clinical conditions. A total of 665 (54.5%) cultures were sterile after 24 h of incubation, 128 (10.5%) showed growth of no significance, 54 (4.4%) showed mixed growth of doubtful significance and 17 (1.4%) showed gross Discussion Till now very few studies have been published in literature that compared automated culture techniques with conventional culture [[12], [13], [14], [15]]. The Postgraduate Institute of Medical Education and Research (PGIMER) is a tertiary care health centre with a capacity of 2200 beds. Approximately 40,000–45,000 urine samples are processed annually in our laboratory. This study was planned to evaluate the diagnostic accuracy of HB&L uroquattro in comparison to conventional culture in hopes of Conclusion HB&L Uroquattro seems to be a reliable instrument for screening out negative urine specimens and the positive samples should be subjected to conventional urine culture for identification and antibiotic sensitivity. We do not recommend direct microbial identification from UQ vials in cases of positive samples. With the help of this technique, time, manpower and cost were significantly reduced with a significant impact on the rapid confirmation and exclusion of UTI with its effect on Authors’ contributions Conceptualization : Neelam Taneja, Bhawna Sharma. Data curation : Bhawna Sharma, Neelam Taneja, Rashmi Sharma, Pinky Shankar. Formal analysis : Neelam Taneja, Bhawna Sharma, Balvinder Mohan. Funding acquisition: Neelam Taneja. Methodology: Neelam Taneja, Bhawna Sharma, Balvinder Mohan. Project administration : Neelam Taneja, Balvinder Mohan. Resources : Neelam Taneja. Software: Bhawna Sharma, Neelam Taneja, Vikas Lakhanpal. Supervision : Neelam Taneja. Validation : Neelam Taneja, Balvinder Mohan, Shrawan Kumar Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. References (23) W. Dimech et al. Evaluation of an automated urinalysis system for testing urine chemistry, microscopy and culture Pathology (2002) B. Mohan et al. Evaluation of matrix assisted laser desorption ionisation-time of flight mass spectrometry in direct identification of bacteriuria from urine samples Indian J Med Microbiol (2020) W.J. McIsaac et al. Overestimation error and unnecessary antibiotic prescriptions for acute cystitis in adult women Med Decis Making (2011) S. Kant et al. The Ballabgarh Health and Demographic Surveillance System (CRHSP-AIIMS) Int J Epidemiol (2013) R. Vasudevan Urinary tract infection:an overview of the infection and the associated risks factors J Microbiology Exp (2014) P. Ayazi et al. Comparison of urine culture and urine dipstick analysis in diagnosis of urinary tract infection Acta Med Iran (2007) M. Demi et al. Urinary tract infections in newborns: sensitivity, specifi city, and predictive value of urinary screening with the reagent strip test Pediatr Med e Chir (1993) E.H. Kass Asymptomatic infections of the urinary tract Tran.Assoc. Am. Physicians (1956) B. Lipsky et al. Diagnosis of bacteriuria in men: specimen collection and culture interpretation J Infect Dis (1987) G. Pappas Laboratory in the diagnosis and management of urinary tract infections Med Clin (1991) M. Pezlo Detection of urinary tract infections by rapid methods Clin Microbiol Rev (1988) Navigate Down View more references Cited by (0) Recommended articles (6) View full text © 2023 Indian Association of Medical Microbiologists. Published by Elsevier B.V. All rights reserved. About ScienceDirect Remote access Shopping cart Advertise Contact and support Terms and conditions Privacy policy We use cookies to help provide and enhance our service and tailor content and ads. By continuing you agree to the use of cookies . Copyright © 2023 Elsevier B.V. or its licensors or contributors. ScienceDirect® is a registered trademark of Elsevier B.V. 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