Physicochemical parameters affecting the adhesion of ciprofloxacin-resistant Escherichia coli to activated sludge.

To investigate the physicochemical conditions necessary to stably remove antibiotic-resistant bacteria (ARB) via contact with activated sludge (AS), the adhesion of ciprofloxacin (CIP)-resistant and -susceptible Escherichia coli to AS was simulated by contact tests in the laboratory. The CIP-resistant E. coli and susceptible E. coli were removed by a 3 log smaller concentration by a 5 h contact test at maximum. Considering the hydraulic retention time of a reaction tank (∼5 h) and step-feeding operation, we considered the removal rate of E. coli in the current simulated contact test to be in agreement with the actual situation where 1-2 log concentrations of E. coli were reported to be removed from an AS reaction tank. With the increase in the AS concentration and/or dissolved oxygen, the removal rate of E. coli increased. The removal rate of CIP-resistant E. coli was greater than that of susceptible E. coli under all experimental conditions. Although the mechanism by which CIP-resistant E. coli preferably adhered to AS was not clearly understood in detail, finding optimum conditions under which bacteria, including ARB, were efficiently removed by the AS process may be possible.

Evolution of Antibiotic Resistance in Escherichia coli and Klebsiella pneumoniae from Urine Cultures.

OBJECTIVE: Determine the evolution of antibiotic resistance of symptomatic bacteriuria caused by Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) in Granada. MATERIAL AND METHOD: A descriptive retrospective study was carried out, including antibiograms of urine cultures in which microorganisms identified as E. coli and K. pneumoniae, were isolated in the Microbiology laboratory of the Hospital Universitario Virgen de las Nieves (Granada, Spain) between January 2016 and June 2021. RESULTS: E. coli was the most frequent isolate (10,048) and its resistance to ampicillin (59.45%) and ticarcillin (59.59%), and the increase to cefepime (15.07%) and amoxicillin-clavulanic acid (17.67%) is noteworthy. K. pneumoniae (2222) is notable for resistance to Fosfomycin (27.91%) and an increase to ciprofloxacin (37.79%) and amoxicillin-clavulanic acid (36.63%). Resistance is generally higher in hospitalized patients, males, and adults. CONCLUSIONS: Antibiotic resistance to the studied Enterobacteriaceae is on the rise, requiring empirical treatment targeted to the population area.

Community-Acquired Uropathogenic Escherichia coli, Antimicrobial Susceptibility, and Extended-Spectrum Beta-Lactamase Detection.

INTRODUCTION: Urinary tract infection is the second-leading reason for consults in primary health care. Bacterial urinary tract infections are the most common, of which Escherichia coli is the main etiologic agent. Antimicrobial resistance and multidrug resistance complicate effective community treatment, especially if resistance is caused by extended-spectrum beta-lactamase production. WHO recommends that antimicrobial susceptibility be evaluated in different regions of the world at different times. Community-acquired E. coli's susceptibility to colistin has not yet been studied in Cuba, and mcr-1 gene screening is necessary. OBJECTIVE: Evaluate community-acquired uropathogenic E. coli isolates' susceptibility to antibiotics, including colistin, and identify extended-spectrum beta-lactamase-producing bacteria. METHODS: We conducted a descriptive cross-sectional study that included 281 community-acquired uropathogenic E. coli isolates (153 from the Isle of Youth Special Municipality's Hygiene, Epidemiology, and Microbiology Center and 128 from Microbiology Laboratories of 7 institutions in Havana) from June 2016 through July 2018. We used the disk diffusion method to determine susceptibility to ampicillin, ampicillin/sulbactam, cefazolin, trimethoprim/sulfamethoxazole, ciprofloxacin, nitrofurantoin and fosfomycin. The disk elution method was used to determine susceptibility to colistin. The combined disk method was used to identify extended-spectrum beta-lactamases. Estimates were made regarding the frequency and percentages of antimicrobial susceptibility and resistance, as well as multidrug-resistance patterns. RESULTS: Of the 281 isolates, 68.3% (192/281) were resistant to ampicillin, 54.8% (154/281) were resistant to ciprofloxacin, and 49.5% (139/281) were resistant to trimethoprim/sulfamethoxazole. Resistance to colistin was not detected. On the other hand, 14.2% (40/281) were susceptible to the 8 antibiotics we evaluated, 22.1% (62/281) showed resistance to only 1 antibiotic, and 63.7% (179/281) were resistant to 2 or more antibiotics. In the extended-spectrum beta-lactamase determination, 34.5% (97/281) had inhibition zones ≤14 mm with cefazolin. Of those with inhibition zones, 64.9% (63/97) were positive in the phenotype test, and 35.1% (34/97) were negative. In extended-spectrum beta-lactamase-producing bacteria, 1.6% (1/63) were resistant to fosfomycin, and 3.2% (2/63) were resistant to nitrofurantoin. The most common multidrug-resistance pattern (22.9%; 30/131) was to ampicillin/sulbactam, ampicillin, cefazolin, ciprofloxacin, and trimethoprim/sulfamethoxazole. CONCLUSIONS: Uropathogenic E. coli resistance to the antibiotics most frequently used in community medical practice is quite common, and extended-spectrum beta-lactamase-producing bacteria is the mechanism for beta-lactam antibiotic resistance. Multidrug-resistance patterns include resistance to the antibiotics most used in community-acquired infections. Fosfomycin and nitrofurantoin are the most active in extended-spectrum beta-lactamase producing bacteria. All the isolates were susceptible to colistin.

Novel Synergistic Activity of Quercus infectoria Gall Extract with Ceftazidime Against Standard and Multiple Drug Resistant Pseudomonas aeruginosa and Escherichia coli Isolates.

BACKGROUND: Multidrug resistance pathogens are important heath challenges. In this study, the antibacterial activity of 20 plant extracts was tested against standard as well as 20 multidrug-resistant (MDR) strains of Pseudomonas aeruginosa and Escherichia coli. The most active plant extract (Quercus infectoria) was selected for the synergistic activity assay. METHODS: Plant extracts were prepared by maceration using water, methanol and ethanol. The antibacterial activity of extracts was determined by both broth and agar dilution methods. The synergistic activity of QIG with ceftazidime (CAZ) was evaluated by checker board assay. Antioxidant activity was determined by colorimetric Ferric reducing antioxidant power (FRAP) assay. RESULTS: Only the methanol extract of QIG inhibited the growth of all the bacterial strains at a concentration of 1000 µg/mL. Other active extracts were Myrtus communis and Eucalyptusglobulus inhibiting the growth of most bacterial strains tested at 2000 µg/ mL. In checker board assay, the minimum inhibitory concentration (MIC) to both QIG extract and CAZ was reduced. The MIC of CAZ was reduced from 64-4096 µg/mL to 4 µg/mL for P. aeruginosa and to 16 µg/mL for E. coli isolates. CONCLUSION: The QIG extract exhibited potent antioxidant activity determined by FRAP assay. The result of this study showed a strong synergistic activity between QIC and CAZ on P. aeruginosa and E. coli. The activity within ethyl acetate-methanol (7:3) fraction indicates that the active components of the plant have a semi-polar nature and further work with this fraction may lead to understanding the mechanism of this synergistic activity.