scholarly journals Antimicrobial Activity of Ceftazidime-Avibactam and Comparators against Levofloxacin-Resistant Escherichia Coli Collected from Four Geographic Regions, 2012–2018

Author(s):  
Gregory Stone

Abstract Background: Increases in resistance to fluoroquinolones have been correlated with the use of levofloxacin in the treatment of infections caused by Escherichia coli. The analysis presents the in vitro activity of ceftazidime-avibactam and comparator agents against 10,840 levofloxacin-resistant E. coli isolates collected from four geographic regions (Africa/Middle East, Europe, Asia/South Pacific, Latin America) between 2012 and 2018.Methods: Non-duplicate clinical isolates of E. coli were collected from participating centres and shipped to International Health Management Associates, Inc. [IHMA], Schaumburg, IL, USA. Susceptibility testing was performed with frozen broth microdilution panels manufactured by IHMA, according to CLSI guidelines. Levofloxacin-resistance was defined at a minimum inhibitory concentration of ≥2 mg/L. Isolates collected between 2012 and 2015 were tested for extended-spectrum β-lactamase (ESBL) activity by determining susceptibility to cefotaxime, cefotaxime-clavulanate, ceftazidime, and ceftazidime-clavulanate as recommended by CLSI guidelines. Isolates collected between 2016 and 2018 were identified as ESBL-positive by genotype using multiplex polymerase chain reaction assays. Results: A total of 74.8% of levofloxacin-resistant E. coli isolates in the analysis were from three culture sources: urinary tract infections (N = 3,229; 29.8%), skin and skin structure infections (N = 2,564; 23.7%) and intra-abdominal infections (N = 2,313; 21.3%). Susceptibility rates to ceftazidime-avibactam were consistently high in all regions against both ESBL-positive (97.0% in Asia/South Pacific to 99.7% in Africa/Middle East and Latin America) and ESBL-negative isolates (99.4% in Asia/South Pacific to 100% in Latin America). Susceptibility was also high in each region among ESBL-positive and ESBL-negative isolates to colistin (≥98.5%), imipenem (≥96.5%), meropenem (≥96.5%) and tigecycline (≥94.1%). Conclusions: Antimicrobial susceptibility to ceftazidime-avibactam among levofloxacin-resistant E. coli isolates, including ESBL-positive isolates, collected from four geographical regions between 2012 and 2018 was consistently high. Susceptibility to the comparator agents colistin, tigecycline, imipenem and meropenem was also high.

2005 ◽  
Vol 49 (6) ◽  
pp. 2343-2351 ◽  
Author(s):  
Patricia Komp Lindgren ◽  
Linda L. Marcusson ◽  
Dorthe Sandvang ◽  
Niels Frimodt-Møller ◽  
Diarmaid Hughes

ABSTRACT Resistance to fluoroquinolones in urinary tract infection (UTIs) caused by Escherichia coli is associated with multiple mutations, typically those that alter DNA gyrase and DNA topoisomerase IV and those that regulate AcrAB-TolC-mediated efflux. We asked whether a fitness cost is associated with the accumulation of these multiple mutations. Mutants of the susceptible E. coli UTI isolate Nu14 were selected through three to five successive steps with norfloxacin. Each selection was performed with the MIC of the selected strain. After each selection the MIC was measured; and the regions of gyrA, gyrB, parC, and parE, previously associated with resistance mutations, and all of marOR and acrR were sequenced. The first selection step yielded mutations in gyrA, gyrB, and marOR. Subsequent selection steps yielded mutations in gyrA, parE, and marOR but not in gyrB, parC, or acrR. Resistance-associated mutations were identified in almost all isolates after selection steps 1 and 2 but in less than 50% of isolates after subsequent selection steps. Selected strains were competed in vitro, in urine, and in a mouse UTI infection model against the starting strain, Nu14. First-step mutations were not associated with significant fitness costs. However, the accumulation of three or more resistance-associated mutations was usually associated with a large reduction in biological fitness, both in vitro and in vivo. Interestingly, in some lineages a partial restoration of fitness was associated with the accumulation of additional mutations in late selection steps. We suggest that the relative biological costs of multiple mutations may influence the evolution of E. coli strains that develop resistance to fluoroquinolones.


Author(s):  
Rachana Kanaujia ◽  
Amit Kumar ◽  
Malay Bajpai

Background: Urinary tract infections (UTIs) are one of the most common infections. For treatment of UTIs, there are limited antibiotics due to increased resistance among uropathogens. Two older antibiotics; Nitrofurantoin and Fosfomycin have become novel oral therapeutic options against uropathogens. Aim of the study was to identify UTI causing micro-organisms and evaluate in-vitro activity of nitrofurantoin and fosfomycin against most common isolated organism (E. coli).Methods: Results of urine samples culture and susceptibility testing over a period of 1 year were analysed and included in this study.Results: Micro-organisms were isolated from 568 urine samples. Most commonly isolated organism was Escherichia coli (40.50%), followed by Klebsiella spp. (20.07%) and Staphylococcus spp. (17.07%). Susceptibility of E. coli to nitrofurantoin and fosfomycin was 91.74% and 65.65% respectively. Conclusion: Good activity of nitrofurantoin and fosfomycin against E. coli indicates that these two drugs are potential therapeutic alternatives for urinary tract infections.


1998 ◽  
Vol 66 (8) ◽  
pp. 3856-3861 ◽  
Author(s):  
A. E. Stapleton ◽  
M. R. Stroud ◽  
S. I. Hakomori ◽  
W. E. Stamm

ABSTRACT Women with a history of recurrent Escherichia coliurinary tract infections (UTIs) are significantly more likely to be nonsecretors of blood group antigens than are women without such a history, and vaginal epithelial cells (VEC) from women who are nonsecretors show enhanced adherence of uropathogenic E. coli isolates compared with cells from secretors. We previously extracted glycosphingolipids (GSLs) from native VEC and determined that nonsecretors (but not secretors) selectively express two extended globoseries GSLs, sialosyl galactosyl globoside (SGG) and disialosyl galactosyl globoside (DSGG), which specifically bound uropathogenicE. coli R45 expressing a P adhesin. In this study, we demonstrated, by purifying the compounds from this source, that SGG and DSGG are expressed in human kidney tissue. We also demonstrated that SGG and DSGG isolated from human kidneys bind uropathogenic E. coli isolates expressing each of the three classes ofpap-encoded adhesins, including cloned isolates expressing PapG from J96, PrsG from J96, and PapG from IA2, and the wild-type isolates IA2 and R45. We metabolically 35S labeled these five E. coli isolates and measured their relative binding affinities to serial dilutions of SGG and DSGG as well as to globotriaosylceramide (Gb3) and globotetraosylceramide (Gb4), two other globoseries GSLs present in urogenital tissues. Each of the five E. coli isolates bound to SGG with the highest apparent avidity compared with their binding to DSGG, Gb3, and Gb4, and each isolate had a unique pattern of GSL binding affinity. These studies further suggest that SGG likely plays an important role in the pathogenesis of UTI and that its presence may account for the increased binding of E. colito uroepithelial cells from nonsecretors and for the increased susceptibility of nonsecretors to recurrent UTI.


2014 ◽  
Vol 58 (12) ◽  
pp. 7225-7233 ◽  
Author(s):  
Jascha Vervoort ◽  
Basil Britto Xavier ◽  
Andrew Stewardson ◽  
Samuel Coenen ◽  
Maciek Godycki-Cwirko ◽  
...  

ABSTRACTNitrofurantoin has been used for decades for the treatment of urinary tract infections (UTIs), but clinically significant resistance inEscherichia coliis uncommon. Nitrofurantoin concentrations in the gastrointestinal tract tend to be low, which might facilitate selection of nitrofurantoin-resistant (NIT-R) strains in the gut flora. We subjected two nitrofurantoin-susceptible intestinalE. colistrains (ST540-p and ST2747-p) to increasing nitrofurantoin concentrations under aerobic and anaerobic conditions. Whole-genome sequencing was performed for both susceptible isolates and selected mutants that exhibited the highest nitrofurantoin resistance levels aerobically (ST540-a and ST2747-a) and anaerobically (ST540-an and ST2747-an). ST540-a/ST540-an and ST2747-a (aerobic MICs of >64 μg/ml) harbored mutations in the known nitrofurantoin resistance determinantsnfsAand/ornfsB, which encode oxygen-insensitive nitroreductases. ST2747-an showed reduced nitrofurantoin susceptibility (aerobic MIC of 32 μg/ml) and exhibited remarkable growth deficits but did not harbornfsA/nfsBmutations. We identified a 12-nucleotide deletion inribE, encoding lumazine synthase, an essential enzyme involved in the biosynthesis of flavin mononucleotide (FMN), which is an important cofactor for NfsA and NfsB. Complementing ST2747-an with a functional wild-type lumazine synthase restored nitrofurantoin susceptibility. Six NIT-RE. coliisolates (NRCI-1 to NRCI-6) from stools of UTI patients treated with nitrofurantoin, cefuroxime, or a fluoroquinolone harbored mutations innfsAand/ornfsBbut notribE. Sequencing of theribEgene in six intestinal and three urinaryE. colistrains showing reduced nitrofurantoin susceptibility (MICs of 16 to 48 μg/ml) also did not identify any relevant mutations. NRCI-1, NRCI-2, and NRCI-5 exhibited up to 4-fold higher anaerobic MICs, compared to the mutants generatedin vitro, presumably because of additional mutations in oxygen-sensitive nitroreductases.


2020 ◽  
Vol 86 (13) ◽  
Author(s):  
Allyson E. Shea ◽  
Juan Marzoa ◽  
Stephanie D. Himpsl ◽  
Sara N. Smith ◽  
Lili Zhao ◽  
...  

ABSTRACT Urinary tract infections (UTI), the second most diagnosed infectious disease worldwide, are caused primarily by uropathogenic Escherichia coli (UPEC), placing a significant financial burden on the health care system. High-throughput transposon mutagenesis combined with genome-targeted sequencing is a powerful technique to interrogate genomes for fitness genes. Genome-wide analysis of E. coli requires random libraries of at least 50,000 mutants to achieve 99.99% saturation; however, the traditional murine model of ascending UTI does not permit testing of large mutant pools due to a bottleneck during infection. To address this, an E. coli CFT073 transposon mutant ordered library of 9,216 mutants was created and insertion sites were identified. A single transposon mutant was selected for each gene to assemble a condensed library consisting of 2,913 unique nonessential mutants. Using a modified UTI model in BALB/c mice, we identified 36 genes important for colonizing the bladder, including purB, yihE, and carB. Screening of the condensed library in vitro identified yigP and ubiG to be essential for growth in human urine. Additionally, we developed a novel quantitative PCR (qPCR) technique to identify genes with fitness defects within defined subgroups of related genes (e.g., genes encoding fimbriae, toxins, etc.) following UTI. The number of mutants within these subgroups circumvents bottleneck restriction and facilitates validation of multiple mutants to generate individual competitive indices. Collectively, this study investigates the bottleneck effects during UTI, provides two techniques for evading those effects that can be applied to other disease models, and contributes a genetic tool in prototype strain CFT073 to the field. IMPORTANCE Uropathogenic Escherichia coli strains cause most uncomplicated urinary tract infections (UTI), one of the most common infectious diseases worldwide. Random transposon mutagenesis techniques have been utilized to identify essential bacterial genes during infection; however, this has been met with limitations when applied to the murine UTI model. Conventional high-throughput transposon mutagenesis screens are not feasible because of inoculum size restrictions due to a bottleneck during infection. Our study utilizes a condensed ordered transposon library, limiting the number of mutants while maintaining the largest possible genome coverage. Screening of this library in vivo, and in human urine in vitro, identified numerous candidate fitness factors. Additionally, we have developed a novel technique using qPCR to quantify bacterial outputs following infection with small subgroups of transposon mutants. Molecular approaches developed in this study will serve as useful tools to probe in vivo models that are restricted by anatomical, physiological, or genetic bottleneck limitations.


Antibiotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 181
Author(s):  
Soo Tein Ngoi ◽  
Cindy Shuan Ju Teh ◽  
Chun Wie Chong ◽  
Kartini Abdul Jabar ◽  
Shiang Chiet Tan ◽  
...  

The increasing prevalence of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae has greatly affected the clinical efficacy of β-lactam antibiotics in the management of urinary tract infections (UTIs). The limited treatment options have resulted in the increased use of carbapenem. However, flomoxef could be a potential carbapenem-sparing strategy for UTIs caused by ESBL-producers. Here, we compared the in vitro susceptibility of UTI-associated ESBL-producers to flomoxef and established β-lactam antibiotics. Fifty Escherichia coli and Klebsiella pneumoniae strains isolated from urine samples were subjected to broth microdilution assay, and the presence of ESBL genes was detected by polymerase chain reactions. High rates of resistance to amoxicillin-clavulanate (76–80%), ticarcillin-clavulanate (58–76%), and piperacillin-tazobactam (48–50%) were observed, indicated by high minimum inhibitory concentration (MIC) values (32 µg/mL to 128 µg/mL) for both species. The ESBL genes blaCTX-M and blaTEM were detected in both E. coli (58% and 54%, respectively) and K. pneumoniae (88% and 74%, respectively), whereas blaSHV was found only in K. pneumoniae (94%). Carbapenems remained as the most effective antibiotics against ESBL-producing E. coli and K. pneumoniae associated with UTIs, followed by flomoxef and cephamycins. In conclusion, flomoxef may be a potential alternative to carbapenem for UTIs caused by ESBL-producers in Malaysia.


2021 ◽  
Vol 9 (7) ◽  
pp. 1501
Author(s):  
Gabriella Piatti ◽  
Laura De Ferrari ◽  
Anna Maria Schito ◽  
Anna Maria Riccio ◽  
Susanna Penco ◽  
...  

Urinary tract infections are often polymicrobial and are mainly due to uropathogenic Escherichia coli (UPEC). We previously demonstrated a link among clinical fluoroquinolone susceptible E. coli reducing in vitro urothelial interleukin-8 (CXCL8) induced by E. coli K-12, polymicrobial cystitis, and pyuria absence. Here, we evaluated whether fifteen clinical fluoroquinolone susceptible UPEC were able to reduce CXCL8 induced by Enterococcus faecalis that had been isolated from the same mixed urines, other than CXCL8 induced by E. coli K-12. We also evaluated the connection between fluoroquinolone susceptibility and pathogenicity by evaluating the immune modulation of isogenic gyrA, a mutant UPEC resistant to ciprofloxacin. Using the 5637 bladder epithelial cell line, we observed that lower CXCL8 induced the most UPEC isolates than K-12 and the corresponding E. faecalis. During coinfections of UPEC/K-12 and UPEC/E. faecalis, we observed lower CXCL8 than during infections caused by K-12 and E. faecalis alone. UPEC strains showed host–pathogen and pathogen–pathogen interaction, which in part explained their persistence in the human urinary tract and coinfections, respectively. Mutant UPEC showed lower modulating activity with respect to the wildtypes, confirming the connection between acquired fluoroquinolone resistance and the decrease of innate microbial properties.


2019 ◽  
Author(s):  
Eric C. DiBiasio ◽  
Hilary J. Ranson ◽  
James R. Johnson ◽  
David C. Rowley ◽  
Paul S. Cohen ◽  
...  

AbstractThe layer of peptidoglycan surrounding bacteria provides structural integrity for the bacterial cell wall. Many organisms, including human cells and diverse bacteria, detect peptidoglycan fragments that are released as bacteria grow. Uropathogenic Escherichia coli (UPEC) strains are the leading cause of human urinary tract infections (UTIs) and many patients experience recurrent infection after successful antibiotic treatment. The source of recurrent infections may be persistent bacterial reservoirs in vivo that are in a quiescent state and, thus, are not susceptible to antibiotics. Here, we show that multiple UPEC strains require a quorum to proliferate in vitro with glucose as the sole carbon source; at low density, the bacteria remain viable but enter a quiescent, non-proliferative state. Of all clinical UPEC isolates tested to date, 35% (51/145) enter this quiescent state, including archetypal strains CFT073 (from classic endemic lineage ST73) and JJ1886 (from recently emerged, multidrug-resistant pandemic lineage ST131). We further show that quorum-dependent UPEC quiescence is prevented and reversed by small molecules, called proliferants, that stimulate growth, such as L-lysine, L-methionine, and peptidoglycan (PG) stem peptides, including an isolated PG pentapeptide from Staphylococcus aureus. Together, our results indicate that (i) uptake of L-lysine and (ii) PG peptide sensing by UPEC modulate the quorum-regulated decision to proliferate and further demonstrate that PG fragments are important for intra- and interspecies signaling in pathogenic E. coli.


2017 ◽  
Vol 53 (2) ◽  
pp. 94
Author(s):  
Sukarjati Sukarjati ◽  
Susie Amilah

Escherichia coli (E. coli), a major cause of male genital tract infections, is asymptomatic and may result in male infertility. We have succeeded in isolating and characterizing proteins of E. Pili coli isolates from semen of infertile men who function as adhesin with a molecular weight (MW) 32.2 kDa. This study aims to prove the ability of IgG results adhesion proteins induced pili of E. MW coli 32.2 kDa as opsonin to determine the value of the activity and phagocytic capacity and as an anti- adhesion by calculating the average number of E. coli that attached to human spermatozoa. E. coli infertile men's semen were cultured using standard bacteriology. Peritoneal macrophages were isolated from mice. Spermatozoa from donors were prepared using Sil with Select Plus. IgG was obtained from mice immunized with (1) PBS (control), (2) E. coli pili adhesion protein isolated from infertile men semen with MW of 32.2 kDa and (3) weakened E. coli isolated from infertile men's semen. Phagocytic activity value was determined by counting the number of cells activated macrophage phagocytosis process in 100 cells. Phagocytic capacity value was determined by counting the number of bacteria ingested by 25 macrophages. Anti-adhesion test was done by counting the number of bacteria attached to 100 spermatozoa. The results of this study showed difference (p=0.000) in phagocytic activity and phagocytic capacity (p=0.000) between treatment (1) and (2), and between treatment (1) to (3). However, treatment (2) and (3) did not differ neither in phagocytic activity (p=0.693) nor in phagocytosis capacity (p=0.125). Anti-adhesion test produces difference (p=0.000) in the number of E. coli that attached to human spermatozoa between treatments (1) and treatment (2), and between treatments (1) and (3). The number of E. coli that attached to human spermatozoa between treatment (2) and treatment (3) was not significantly different (p=0.371). In conclusion, IgG from the induction of E. coli pili adhesion protein of infertile men semen isolates with MW of 32.2 kDa can increase phagocytic activity and capacity as well as serve as an anti- adhesion. Thus, IgG from the induction of E. coli pili adhesion protein of infertile men semen isolates with MW of 32.2 kDa is protective against in vitro E. coli infection, so that it can be used as material to prevent male reproductive tract infections due to E. coli.


2017 ◽  
Vol 66 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Sarah M. Abdelhamid ◽  
Rania R. Abozahra

Escherichia coli is one of the most frequent causes of urinary tract infections. Efflux system overexpression is reported to contribute to E. coli resistance to several antibiotics. Our aim in this study was to investigate the relation between antibiotic resistance and the expression of the efflux pump genes acrA and mdfA in E. coli by real-time reverse transcription-PCR. We tested the in vitro susceptibilities to 12 antibiotics in 28 clinical isolates of E. coli obtained from urine samples. We also determined the minimum inhibitory concentrations of levofloxacin to these samples. We then revealed significant correlations between the overexpression of both mdfA and acrA and MICs of levofloxacin. In conclusion, we demonstrated that the increased expression of efflux pump genes such as mdfA and acrA can lead to levofloxacin resistance in E. coli. These findings contribute to further understanding of the molecular mechanisms of efflux pump systems and how they contribute to antibiotic resistance.


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