MIC versus MBEC to Determine the Antibiotic Sensitivity of <i>Staphylococcus aureus</i> in Peritoneal Dialysis Peritonitis

Girard, Louis-Philippe; Ceri, Howard; Gibb, A.P.; Olson, Merle E.; Sepandj, Farshad

doi:10.3747/pdi.2010.00010

Cited by 73 publications

(64 citation statements)

References 14 publications

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“…To kill the microorganisms in biofilm-related implant infections, much higher antimicrobial concentrations are needed. The minimum biofilm eradication concentration (MBEC), an in vitro estimate of the lowest antimicrobial concentration that will kill all the microorganisms in a biofilm, including the persister cells, can be hundreds-to thousands-times higher than the MIC for the same antimicrobial-microorganism pair [1,[5][6][7][16][17][18]. The clinically important distinction between MBEC for bacteria in biofilm and MIC or MBC for bacteria in a planktonic (floating) state is that persister cells in biofilm are not accessible to killing by the host.…”

Section: Introductionmentioning

confidence: 99%

Biofilm Antimicrobial Susceptibility Increases With Antimicrobial Exposure Time

Castaneda

McLaren

Tavaziva

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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Background The antimicrobial concentration required to kill all the bacteria in a biofilm, known as the minimum biofilm eradication concentration (MBEC), is typically determined in vitro by exposing the biofilm to serial concentrations of antimicrobials for 24 hours or less. Local delivery is expected to cause high local levels for longer than 24 hours. It is unknown if longer antimicrobial exposures require the same concentration to eradicate bacteria in biofilm. Questions/purposes Does MBEC change with increased antimicrobial exposure time? Methods Biofilms were grown for 24 hours using five pathogens (methicillin-sensitive Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa) and then exposed to four antimicrobials regimens: tobramycin, vancomycin, and tobramycin combined with vancomycin in 3:1 and 1:1 ratios by weight in concentrations of 62.5, 125, 250, 500, 1000, 2000, 4000, and 8000 lg/mL for three durations, 1, 3, and 5 days, in triplicate. MBEC was measured as the lowest concentration that killed all bacteria in the biofilm determined by 21-day subculture. Results MBEC was lower when antimicrobial exposure time was longer. For the staphylococcus species, the MBEC was lower when exposure time was 5 days than 1 day in 11 of 12 antimicrobial/microorganism pairs. The MBEC range for these 11 pairs on Day 1 was 4000 to[8000 lg/mL and on Day 5 was \ 250 to 8000 lg/mL. MBEC for tobramycin/P. aeruginosa was 2000 lg/mL on Day 1 and B 250 lg/mL on Day 5, and for E. coli, 125 lg/mL on Day 1 and B 62.5 on Day 5. Conclusions Although antimicrobial susceptibility was lower for longer exposure times in the microorganisms we studied, confirmation is required for other pathogens. Clinical Relevance One-day MBEC assays may overestimate the local antimicrobial levels needed to kill organisms in biofilm if local levels are sustained at MBEC or above for longer than 24 hours. Future studies are needed to confirm that antimicrobial levels achieved clinically from local delivery are above the MBEC at relevant time points and to confirm that MBEC for in vitro microorganisms accurately represents MBEC of in vivo organisms in an clinical infection.

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Section: Introductionmentioning

confidence: 99%

Biofilm Antimicrobial Susceptibility Increases With Antimicrobial Exposure Time

Castaneda

McLaren

Tavaziva

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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“…In studies of well-characterized bacterial strains [12,31,49] and clinical bacterial isolates from biofilmbased infections [6,45,48,54], the antimicrobial concentration required to kill bacteria in biofilms can be 100 to 1000 times greater than the minimum inhibitory concentration for the planktonic form. Because the antimicrobial concentrations required to manage biofilm often exceed the concentrations at which systemic toxicity is prohibitive, surgical débridement and local antimicrobial delivery are necessary [10,13,14,56].…”

Section: Introductionmentioning

confidence: 99%

Local Gentamicin Delivery From Resorbable Viscous Hydrogels Is Therapeutically Effective

Overstreet

McLaren

Calara

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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Background Local delivery can achieve the high antimicrobial concentrations necessary to kill biofilm-related microbes. Degradation times for resorbable carriers are too long. Hydrogels (gels of hydrophilic polymer in water) can degrade faster but release antimicrobials too quickly. We previously developed hydrogels based on the copolymer poly(N-isopropylacrylamide-co-dimethyl-c-butyrolactone acrylate-co-Jeffamine 1 M-1000 acrylamide) (PNDJ) with delivery times of several days with complete degradation in less than 6 weeks. Questions/purposes We asked: (1) What is the elution profile of gentamicin from PNDJ hydrogels? (2) Is gentamicin released from gentamicin-loaded PNDJ (G-PNDJ) hydrogel effective for treatment of orthopaedic infection? (3) Does local gentamicin delivery from G-PNDJ hydrogel cause renal dysfunction? Methods (1) Two formulations of G-PNDJ, lower dose (1.61 wt%) and higher dose (3.14 wt%), five samples each, were eluted in buffered saline under infinite sink conditions. (2) Infections were induced in 16 New Zealand White rabbits by inserting a Kirschner wire in a devascularized radius segment and inoculating with 7.5 9 10 6 colony-forming units Staphylococcus aureus. At 3 weeks, débridement was performed and a new Kirschner wire was placed in the dead space. Treatment was randomized to higher-dose G-PNDJ or no hydrogel. No systemic antimicrobials were used. Positive culture and acute inflammation on histology were used to determine the presence of infection 4 weeks postdébridement. (3) 3.14 wt% G-PNDJ, 0.75, 1.5, or 3.0 mL, was injected subcutaneously in nine Sprague-Dawley rats, three of each dose. Serum gentamicin, blood urea nitrogen, and creatinine were measured on Days 1, 3, 7, 14, and 28. Results (1) Gentamicin release was sustained over 7 days with the higher-dose formulation release profile similar to release from high-dose antimicrobial-loaded bone cement.(2) Four weeks postdébridement, infection was present in eight of eight no-hydrogel rabbits but zero of eight rabbits treated with G-PNDJ hydrogel (p \ 0.001). (3) Blood urea nitrogen and creatinine were transiently elevated

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“…Urokinase instillation in Tenckhoff catheters was also more common in repeat than in non-repeated peritonitis. Of interest, it has recently been suggested that the minimal biofilm eradication concentration, instead of the minimum inhibitory concentration, may be the preferred therapeutic target for determining antibiotic therapy for confirmed or suspected cases of biofilmassociated repeat infections [39]. On the other hand, it is generally not known whether repeat episodes are caused by the same strain of bacteria hidden in the biofilm-a determination which requires phage typing of the bacterial isolates for confirmation.…”

Section: Treatment Of Repeat Peritonitismentioning

confidence: 99%

Difficult peritonitis cases in children undergoing chronic peritoneal dialysis: relapsing, repeat, recurrent and zoonotic episodes

Bakkaloğlu

Warady

2014

Pediatr Nephrol

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Despite technological improvements in dialysis connectology and dialysis technique, peritonitis remains the most common and most significant complication of peritoneal dialysis (PD) in children. Most children undergoing chronic PD experience none or only one peritonitis episode, while others have multiple episodes or episodes secondary to unusual organisms. Knowledge of potential risk factors and likely patient outcome is imperative if treatment is to be optimized. In this review we will, in turn, describe episodes of peritonitis that are characterized as either relapsing, recurrent, repeat or zoonosis-related to highlight the clinical issues that are commonly encountered by clinicians treating these infections.

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MIC versus MBEC to Determine the Antibiotic Sensitivity of Staphylococcus aureus in Peritoneal Dialysis Peritonitis

Cited by 73 publications

References 14 publications

Biofilm Antimicrobial Susceptibility Increases With Antimicrobial Exposure Time

Biofilm Antimicrobial Susceptibility Increases With Antimicrobial Exposure Time

Local Gentamicin Delivery From Resorbable Viscous Hydrogels Is Therapeutically Effective

Difficult peritonitis cases in children undergoing chronic peritoneal dialysis: relapsing, repeat, recurrent and zoonotic episodes

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