Incidence of multidrug resistance, pathogenicity island markers, and pathoadaptive FimH mutations in uropathogenic Escherichia coli isolated from asymptomatic hospitalized patients
Asymptomatic uropathogenic Escherichia coli (UPECs) are the leading cause of asymptomatic bacteriuria (ABU) in humans. So this study aimed to identify and characterize ABU UPECs from hospitalized patients of Kolkata, India, with respect to their antibiogram profile, phylogeny, pathogenicity islands, and virulence factor gene acquisition and FimH mutations in comparison to symptomatic UPECs. E. coli was detected biochemically in 44.44% (20/45) and 32.26% (20/62) of urine culture-positive asymptomatic and symptomatic hospitalized individuals respectively. Ninety-five percent of the asymptomatic isolates were multidrug resistant (MDR) compared to the symptomatic isolates (100%). Significant predominance of unknown phylogroup, pathogenicity island markers (PAI IV536, PAI I CFT073), and distribution patterns of different virulence factor genes respectively was evident among both groups. A significant correlation was observed between both groups of isolates with respect to their antibiotic resistances (except imipenem, amikacin, and nitrofurantoin), prevalence of phylogenetic groups and PAIs, and virulence factor gene (fimH, papC, papEF, papGII, iucD, and cnf1) acquisition. Pathoadaptive FimH adhesin mutations, especially hot spot mutation V27A, were detected in 80% asymptomatic isolates mostly reported in symptomatic ones worldwide. Moreover, this is the first study from India that reported incidence of “Unknown” phylogroup, pathogenicity island markers, and potentially pathoadaptive FimH mutations in asymptomatic UPECs isolated from hospitalized patients which further indicated that these ABU E. coli might have originated from their symptomatic counterparts due to unbridled use of unprescribed antibiotics. Therefore, this study demands antibiotic de-escalation along with regular and intricate monitoring at the molecular level for efficient management of ABU that addresses a major public health concern.
The authors would like to express their gratitude to Professor Nandita Basu, Director and Professor Bibhuti Saha, Head, Department of Tropical Medicine, School of Tropical Medicine, Kolkata West Bengal, India, for their kind support.
Consumable support was provided from extramural grant: Department of Science and Technology, Government of West Bengal, India (Grant No. 757 (Sanc.)/ST/P/S&T/12G-21/2014 dated 27.11.14). The work was also supported by INSPIRE fellowship grant from Department of Science &Technology, New Delhi, Government of India (No.-DST/INSPIRE Fellowship/2016/ IF160069 dated November 7, 2016).
Compliance with ethical standards
The present study was approved by the Clinical Research Ethics Committee, School of Tropical Medicine, Kolkata (CREC-STM), Ref no. CREC-STM/317 dated 29/3/16, and informed consent was obtained from all patients for being included in this study.
The authors declare that they have no competing interests.
- Basu S, Mukherjee SK, Hazra A, Mukherjee M (2013) Molecular characterization of uropathogenic Escherichia coli: nalidixic acid and ciprofloxacin resistance, virulent factors and phylogenetic background. J Clin Diagn Res 7:2727–2731Google Scholar
- CLSI (2018) Performance standards for antimicrobial susceptibility testing: 28th informational supplement. M100- S28. Clinical and Laboratory Standards Institute, WayneGoogle Scholar
- Elzayat MA, Barnett-Vanes A, Dabour MF, Cheng F (2017) Prevalence of undiagnosed asymptomatic bacteriuria and associated risk factors during pregnancy: a cross-sectional study at two tertiary centres in Cairo, Egypt. BMJ Open 7:013198–013204Google Scholar
- Kawamura-Sato K, Yoshida R, Shibayama K, Ohta M (2010) Virulence genes, quinolone and fluoroquinolone resistance, and phylogenetic background of uropathogenic Escherichia coli strains isolated in Japan. Jpn J Infect Dis 63:113–115Google Scholar
- Kryger J, Burleigh A, Christensen M, Hopkins W (2015) Genetic evaluation of E. coli strains isolated from asymptomatic children with neurogenic bladders. Int J Chronic Dis 2015:206570–206574Google Scholar
- Lee S, Yu JK, Park K, Oh EJ, Kim SY, Park YJ (2010) Phylogenetic groups and virulence factors in pathogenic and commensal strains of Escherichia coli and their association with blaCTX-M. Ann Clin Lab Sci 40:361–367Google Scholar
- Naderi G, Haghi F, Zeighami H, Hemati F, Masoumian N (2016) Distribution of pathogenicity island (PAI) markers and phylogenetic groups in diarrheagenic and commensal Escherichia coli from young children. Gastroenterol Hepatol Bed Bench 9:316–324Google Scholar
- Venkatesan KD, Chander S, Loganathan K, Victor K (2017) Study on asymptomatic bacteriuria in diabetic patients. Int J Contemp Med Res 4:480–483Google Scholar