DOI: 10.5061/dryad.2z34tmptj
title: Determination of fluoroquinolones concentration among biofilm-forming and non-forming uropathogenic Acinetobacter Calcoaceticus-Baumannii complex and their correlation to fluoroquinolone-resistant genes

description: Acinetobacter spp., the predominant cause of urinary tract
 infection (UTI), is increasingly resistant to fluoroquinolones. Resistance
 to fluoroquinolones poses a serious health problem in the treatment of
 urinary tract infections, which are mostly associated with chromosomal
 mutations encoded by topoisomerase IV. The objective of the study was to
 detect
 the blaOXA-23, qnrB, and acc(6l)-lb-cr
 genes in fluoroquinolone-resistant biofilm-producing ACB
 complex isolated from UTI-suspected patients. A hospital-based
 cross-sectional study was carried out at the Nepal Police Hospital,
 Kathmandu, from April 2019 to January 2021. A total of 598 urine specimens
 were processed, and 78 ACB complex were isolated from a total of
 366 positive cultures, which were identified based on colony morphology,
 Gram’s staining reaction, and various biochemical tests. The antimicrobial
 susceptibility pattern was determined by the modified Kirby-Bauer disk
 diffusion method, and the result was interpreted according to CLSI
 guidelines. The minimum inhibitory concentration (MIC) values of
 levofloxacin and ciprofloxacin for fluoroquinolone-resistant
 ACB were determined by the broth dilution method. The
 fluoroquinolone-resistant ACB was selected for
 blaOXA-23, qnrB, and acc(6l)-lb-cr gene
 detection by polymerase chain reaction. ACB complex was isolated more in
 females 26 (55.31%); outpatients 42 (53.84); and in the age group of 21–40
 years 27 (34.61%). The majority of ACB complex isolates
 were sensitive to Ciprofloxacin 5 (6.41%) and Levofloxacin 10 (12.82%).
 However, most of them were resistant to Ciprofloxacin 64 (82.05%) and
 Levofloxacin 60 (76.92%). A total of 78 (21.31%) ACB complex isolates were
 found to be multidrug resistant. The MICs of Ciprofloxacin and
 Levofloxacin ranged from 4 to 256 μl/ml. Among 78 (82.05%)
 fluoroquinolone-resistant ACB isolates,
 the blaOXA-23 gene was found on 32 (41.02%) isolates,
 the acc(6l)-Ib-cr gene on 3 (3.84%) isolates, and
 the qnrB gene on 1 (1.28%) isolates. The presence of
 blaOXA-23, acc(6l)-Ib-cr, and qnrB genes and
 biofilm formation lead to the emergence of fluoroquinolone-resistant
 strains of the ACB complex. So, the identification of responsible
 genes is required for AMR surveillance and guidelines for empirical
 therapy, which aid in preventing the emergence of antibiotic-resistant
 isolates.
description: Determination of fluoroquinolones concentration among biofilm-forming and
 non-forming uropathogenic Acinetobacter Calcoaceticus-Baumannii complex
 and their correlation to fluoroquinolone-resistant genes Dataset DOI link:
 https://doi.org/10.5061/dryad.2z34tmptj Resistance to antimicrobials is
 rapidly emerging among uropathogens, chiefly attributed to the extensive
 use and misuse of antimicrobial agents. For example, fluoroquinolone,
 which was once considered a highly effective broad-spectrum antibiotic to
 treat infectious diseases, is currently of poor functionality because of
 the emergence of fluoroquinolone-resistant bacteria, limiting the
 selection for treating infections. Of the several resistance mechanisms to
 fluoroquinolones, plasmid-mediated quinolone resistance (PMQR) (blaoxa-23,
 aac(6')-Ib-cr, qnrB) and biofilm formation—the polymicrobial
 community of microbial cells enveloped by extracellular polymeric
 substances—have been identified as the major resistance mechanisms to
 fluoroquinolones in the Acinetobacter Calcoaceticus-Baumannii complex (ACB
 complex). Herein, the dataset is of hospital-visiting patients with
 urinary tract infections caused by non-lactose-fermenting bacteria, the
 ACB complex. The dataset comprises a single sheet. The sheet details
 microbiological findings comprising antimicrobial (drug) resistance
 patterns, biofilm formers or non-formers, inhibitory concentrations of
 ciprofloxacin and levofloxacin, and the presence or absence of
 plasmid-mediated quinolone resistance genes. Both ciprofloxacin and
 levofloxacin are fluoroquinolone antibiotics, and their inhibitory
 concentrations refer to the lowest concentration of an antibiotic that
 will inhibit the visible growth of a ACB complex after overnight
 incubation at 37°C for 24 hours. Data were anonymized with the code. Urine
 samples from which ACB complex strains were isolated were coded with
 serial alphanumeric numbers (S1, S23, S847, etc.). The units of the study
 variables were standard and as follows: (a) Inhibitory concentrations
 μg/mL (b) Optical density (ODtest) AU/cm (c) Cutoff optical density (ODc)
 AU/cm (d) Antimicrobial susceptibility testing mm Biofilm was quantified
 by measuring the absorbance (optical density) at 630nm following the
 solubilization of the attached biofilm in 95% ethanol. The grading of
 biofilm formation was done as per the chart Biofilm formation Rule a) None
 - b) Weak ODtest &lt; ODc c) Moderate ODc &lt; ODtest &lt; 2×ODc d) Strong
 2×ODc &lt; ODtest &lt; 4×ODc ODtest [(OD 1 + OD 2 + and OD 3) / 3] was
 determined as the average of ODs. The cut–off optical density (ODc) was
 set as three standard deviations above the mean OD of the negative
 control. Negative control was the sterile broth. Disc diffusion or
 antimicrobial susceptibility testing was done with the Kirby Bauer Disc
 Diffusion method. The inhibitory concentrations were determined by the
 gold standard broth microdilution technique. Biofilm formers were detected
 by the gold standard microtiter plate method. Molecular characterization
 of plasmid-mediated quinolone resistance genes was done by conventional
 polymerase chain reaction. Except for values of inhibitory concentrations,
 all other data were qualitative and were calculated as frequency
 (percentage) i.e., n (%) in SPSS version 17.0. Quantitative variables
 (i.e., Minimum Inhibitory concentrations 50/ Minimum Inhibitory
 concentrations 90) were calculated as median (interquartile range). MIC50
 and MIC 90 were defined as the minimum concentration at which 50% and 90%
 of the ACB complex strains were inhibited, respectively. While
 quantitative variables were analyzed using a t-test for statistical
 correlations, qualitative variables were tested using a chi-square test at
 a 95% confidence interval. ACB complex = Acinetobacter
 calcoaceticus-baumannii complex, AST = antimicrobial susceptibility
 testing, MIC = minimum inhibitory concentration, n/a in file = not
 available, OD 1= first optical density, OD 2= second optical density, OD
 3= third optical density, ODc = cut-off optical density, CIP =
 ciprofloxacin, LF = levofloxacin, AMP = ampicillin, CTX = cefotaxime, GEN
 = gentamicin, COT = cotrimoxazole, C = chloramphenicol, AMC = amoxicillin
 clavulanate, CPM = cefepime, IMP = imipenem, CL = colistin Readers may
 access the data from the Dryad repository or with a request email to the
 corresponding author, Ajaya Basnet
 ([xlcprk@gmail.com](mailto:xlcprk@gmail.com)), of the article.