The efficacy of immediate versus delayed antibiotic administration on bacterial growth and biofilm production of selected strains of uropathogenic Escherichia coli and Pseudomonas aeruginosa

Abstract

Purpose The treatment of urinary tract infections (UTI) with antibiotics is commonly used, but recurrence and antibiotic resistance have been growing and concerning clinicians. We studied whether the rapid onset of a protective biofilm may be responsible for the lack of effectiveness of antibiotics against selected bacteria.Materials and Methods Two established uropathogenic Escherichia coli strains, UTI89 and CFT073, and two Pseudomonas aeruginosa strains, PA01 and Boston-41501, were studied to establish a reliable biofilm formation process. Bacterial growth (BG) was determined by optical density at 600 nm (OD 600) using a spectrophotometer, while biofilm formation (BF) using crystal violet staining was measured at OD 550. Next, these bacterial strains were treated with clinically relevant antibiotics, ciprofloxacin HCl (200 ng/mL and 2 μg/mL), nitrofurantoin (20 μg/mL and 40 μg/mL) and ampicillin (50 μg/mL) at time points of 0 (T0) or after 6 hours of culture (T6). All measurements, including controls (bacteria -1% DMSO), were done in triplicates and repeated three times for consistency.Results The tested antibiotics effectively inhibited both BG and BF when administered at T0 for UPEC strains, but not when the antibiotic administration started 6 hours later. For Pseudomonas strains, only Ciprofloxacin was able to significantly inhibit bacterial growth at T0 but only at the higher concentration of 2 μg/mL for T6.Conclusion When established UPEC and Pseudomonas bacteria were allowed to culture for 6 hours before initialization of treatment, the therapeutic effect of selected antibiotics was greatly suppressed when compared to immediate treatment, probably as a result of the protective nature of the biofilm.

Therapy of solid tumors using probiotic Symbioflor-2 - restraints and potential

“…We asked if functional analyses may support this well tolerated bacterial phenotype. An ability to form biofilm has been shown to confer resistance to anti-microbial interventions such as protection from innate defense mechanisms or antibiotic treatment [ 51 , 61 – 63 ]. Aside from a preserved capacity to form biofilm on a plate over 20 days (Figure 4A , Supplementary Figure S5 ), the E. coli probiotics were all, with the exception of strain G3/10, unable to deposit extracellular matrix material or extracellular polymeric substances (EPS) in vitro in a standard quantitative biofilm assay (Figure 4B ).…”

Spectrum of antibiotic resistance in UTI caused by Escherichia coli among HIV-infected patients in Uganda: a cross-sectional study

“…The consumed antibiotic agents may inhibit in vitro culture growth of bacteria in urine. Other studies have shown such an inhibiting impact of antibiotic intake on urine culture growth [ 29 ]. As both groups in this analysis were taking cotrimoxazole/dapsone prophylaxis, additional antibiotic intake may not significantly further alter positive culture growth.…”

Ability of chlorhexidine, octenidine, polyhexanide and chloroxylenol to inhibit metabolism of biofilm-forming clinical multidrug-resistant organisms

“…It is estimated that at least 59.5% of isolates from general infection episodes may be acquired as a result of cross-transmission from the environment (Agodi et al, 2007). Biofilm-forming organisms, such as P. aeruginosa and S. aureus , are less susceptible to decontamination efforts, owing to the protective effects of biofilm (Akinbobola et al, 2017; Alhede et al, 2014; Gandee et al, 2015). Persistence of these microorganisms within biofilm can lead to contamination of medical devices and to infection (Auler et al, 2010; Galli et al, 2016; Singhal et al, 2011; Wilson et al, 2012).…”