The stability of carbapenems before and after admixture to PMMA-cement used for replacement surgery caused by Gram-negative bacteria

Lipopolysaccharide (LPS) is a peculiar component of the outer membrane (OM) of many Gram-negative bacteria that renders these bacteria highly impermeable to many toxic molecules, including antibiotics. LPS is assembled at the OM by a dedicated intermembrane transport system, the Lpt (LPS transport) machinery, composed of seven essential proteins located in the inner membrane (IM) (LptB2CFG), periplasm (LptA), and OM (LptDE). Defects in LPS transport compromise LPS insertion and assembly at the OM and result in an overall modification of the cell envelope and its permeability barrier properties. LptA is a key component of the Lpt machine. It connects the IM and OM sub-complexes by interacting with the IM protein LptC and the OM protein LptD, thus enabling the LPS transport across the periplasm. Defects in Lpt system assembly result in LptA degradation whose stability can be considered a marker of an improperly assembled Lpt system. Indeed, LptA recruitment by its IM and OM docking sites requires correct maturation of the LptB2CFG and LptDE sub-complexes, respectively. These quality control checkpoints are crucial to avoid LPS mistargeting. To further dissect the requirements for the complete Lpt transenvelope bridge assembly, we explored the importance of LPS presence by blocking its synthesis using an inhibitor compound. Here, we found that the interruption of LPS synthesis results in the degradation of both LptA and LptD, suggesting that, in the absence of the LPS substrate, the stability of the Lpt complex is compromised. Under these conditions, DegP, a major chaperone–protease in Escherichia coli, is responsible for LptD but not LptA degradation. Importantly, LptD and LptA stability is not affected by stressors disturbing the integrity of LPS or peptidoglycan layers, further supporting the notion that the LPS substrate is fundamental to keeping the Lpt transenvelope complex assembled and that LptA and LptD play a major role in the stability of the Lpt system.

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Reducing the dosing frequency of selective digestive tract decontamination to three times daily provides effective decontamination of Gram-negative bacteria

European Journal of Clinical Microbiology & Infectious Diseases ◽

10.1007/s10096-021-04234-1 ◽

2021 ◽

Author(s):

Jara R. de la Court ◽

Kim C. E. Sigaloff ◽

Thomas Groot ◽

Johan I. van der Spoel ◽

Rogier P. Schade

Keyword(s):

Clinical Outcome ◽

Digestive Tract ◽

Rank Test ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Log Rank Test ◽

Significant Difference ◽

Selective Digestive Tract Decontamination ◽

Dosing Frequency ◽

Before And After

AbstractThis study evaluated the effectiveness of selective digestive tract decontamination (SDD) application three times daily (t.i.d.) compared to the standard four times daily (q.i.d.). Retrospective equivalence (combined non-inferiority and non-superiority design) study with a before-and-after design on a tertiary ICU in which the SDD frequency was reduced from q.i.d. to t.i.d. All patients with ICU admissions ≥72h and with ≥2 surveillance cultures collected on different dates were included in this study. We compared successful decontamination of Gram-negative bacteria (GNB). Furthermore, time to decontamination, ICU-acquired GNB bacteraemia and 28-day mortality were compared between the two groups. In total 1958 ICU admissions (1236 q.i.d., 722 t.i.d). Decontamination was achieved during the first week of admission in 77% and 76% of patients receiving SDD q.i.d and t.i.d., respectively. Successful decontamination within 14 days (without consecutive acquisition of Gram-negative bacteria) was achieved in 69.3% of the admissions with q.i.d. versus 66.8% in t.i.d. SDD (p-value = 0.2519). The proportions of successful decontamination of GNB were equivalent in both groups (−0.025, 98% CI: −0.087; 0.037). There was no significant difference in time to decontamination between the two regimens (log-rank test p-value = 0.55). Incidence (episodes/1000 days) of ICU-acquired GNB bacteraemia was 0.9 in both groups, and OR for death at day 28 in the t.i.d. group compared to the q.i.d. group was 0.99 (95% confidence interval, 0.80–1.21). This study shows that a t.i.d. application regimen achieves similar outcomes to the standard q.i.d. regime, for both microbiological and clinical outcome measures.

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Assessing Effectiveness of Antibiotic Therapy Against Gram-Negative Bacteria in a Saudi Hospital Using a Drug Resistance Index

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.640 ◽

2020 ◽

Vol 41 (S1) ◽

pp. s130-s131

Author(s):

Muhammad Yaseen ◽

Abdulhakeem Althaqafi ◽

Majid Alshamrani ◽

Asim Alsaedi ◽

Farahat Fayssal ◽

...

Keyword(s):

Drug Resistance ◽

Tertiary Care ◽

Resistance Index ◽

Antibiotic Consumption ◽

Antibiotic Prescribing ◽

Gram Negative Bacteria ◽

Single Measure ◽

Gram Negative ◽

Before And After ◽

The Impact

Background: Assessing the effectiveness of antibiotics and communicating the problem of resistance is essential when devising antimicrobial stewardship programs in hospital settings. The drug resistance index (DRI) is a useful tool that combines antibiotic consumption and bacterial resistance into a single measure. In this study, we used the DRI to assess the impact of introducing a new antibiotic restriction form on antibiotic effectiveness for the treatment of gram-negative infections in the intensive care unit (ICU). Methods: We conducted a before-and-after intervention study from 2015 to 2017 at King Abdulaziz Medical City, a tertiary-care facility in Jeddah, Saudi Arabia. The antibiotic susceptibility of gram-negative bacteria and antibiotic prescribing rates for antibiotics indicated for gram-negative bacteria were assessed to evaluate the impact of a new antibiotic restriction form introduced in the ICU in July 2016. Changes in antibiotic effectiveness before and after the intervention were evaluated by calculating the DRI for 4 of the most common gram-negative pathogens and 8 commonly used antibiotic classes. Results: The overall DRI for the adult ICU (59.45) was higher than the hospital-wide DRI (47.96). A higher DRI was evident for carbapenems and antipseudomonal penicillins + β-lactamase inhibitors. A. baumannii had the highest DRI, followed by K. pneumoniae in both the adult ICU and hospital-wide. After implementation of antibiotic restriction in the adult ICU, the DRI for carbapenems was significantly lower in the postintervention phase, from 31.61 to 26.05 (P = 0.031). Conclusions: DRI is a useful tool for tracking the effectiveness of antibiotics over time. The results highlight the importance of having effective antibiotic stewardship program in healthcare settings as well as regular feedback of antibiotic consumption data to the stakeholders to keep the antibiotic prescriptions in check, thereby ensuring their sustained effectiveness.Funding: NoneDisclosures: None

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Effectiveness of Low-Temperature Domestic Laundry on the Decontamination of Healthcare Workers' Uniforms

Infection Control and Hospital Epidemiology ◽

10.1086/662183 ◽

2011 ◽

Vol 32 (11) ◽

pp. 1103-1108 ◽

Cited By ~ 25

Author(s):

N. Lakdawala ◽

J. Pham ◽

M. Shah ◽

J. Holton

Keyword(s):

Low Temperature ◽

Healthcare Workers ◽

Bacterial Load ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Log Reduction ◽

Healthcare Environment ◽

The United Kingdom ◽

Before And After

Objective.Most professionals in the healthcare environment wear uniforms. For the purpose of this study, we concentrated on nurses' uniforms. In the United Kingdom, many nurses are expected to launder their uniforms at home by using a domestic washing machine that frequently has low-temperature wash cycles. We have investigated whether the use of low-temperature wash cycles results in a microbiologically acceptable product to wear on the wards.Methods.We have assessed the bioburden on uniforms before and after laundry and the effectiveness of low-temperature wash cycles and ironing on removal of methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii. We did not assess the role of tumble drying.Results.We demonstrate contamination of uniforms by gram-negative bacteria after wash, the removal of MRSA at low-temperature wash cycles in the presence of detergent, and the eradication of gram-negative bacteria after ironing.Conclusions.Our conclusions are that laundry in a domestic situation at 60°C (140°F) for 10 minutes is sufficient to decontaminate hospital uniforms and reduces the bacterial load by more than 7-log reduction, that items left in the pockets are decontaminated to the same extent, that the addition of either a biological detergent or a nonbiological detergent is beneficial in removing MRSA from experimentally contaminated swatches, and that uniforms become recontaminated with low numbers of principally gram-negative bacteria after laundry but that these are effectively removed by ironing.

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Flexibility and Symmetry of Prokaryotic Genome Rearrangement Reveal Lineage-Associated Core-Gene-Defined Genome Organizational Frameworks

mBio ◽

10.1128/mbio.01867-14 ◽

2014 ◽

Vol 5 (6) ◽

Cited By ~ 11

Author(s):

Yu Kang ◽

Chaohao Gu ◽

Lina Yuan ◽

Yue Wang ◽

Yanmin Zhu ◽

...

Keyword(s):

Horizontal Gene Transfer ◽

Dna Polymerase ◽

Prokaryotic Genome ◽

Core Gene ◽

Gram Negative Bacteria ◽

Gram Negative ◽

The Stability ◽

Definition Of ◽

Species Specific ◽

Core Genes

ABSTRACT The prokaryotic pangenome partitions genes into core and dispensable genes. The order of core genes, albeit assumed to be stable under selection in general, is frequently interrupted by horizontal gene transfer and rearrangement, but how a core-gene-defined genome maintains its stability or flexibility remains to be investigated. Based on data from 30 species, including 425 genomes from six phyla, we grouped core genes into syntenic blocks in the context of a pangenome according to their stability across multiple isolates. A subset of the core genes, often species specific and lineage associated, formed a core-gene-defined genome organizational framework (cGOF). Such cGOFs are either single segmental (one-third of the species analyzed) or multisegmental (the rest). Multisegment cGOFs were further classified into symmetric or asymmetric according to segment orientations toward the origin-terminus axis. The cGOFs in Gram-positive species are exclusively symmetric and often reversible in orientation, as opposed to those of the Gram-negative bacteria, which are all asymmetric and irreversible. Meanwhile, all species showing strong strand-biased gene distribution contain symmetric cGOFs and often specific DnaE (α subunit of DNA polymerase III) isoforms. Furthermore, functional evaluations revealed that cGOF genes are hub associated with regard to cellular activities, and the stability of cGOF provides efficient indexes for scaffold orientation as demonstrated by assembling virtual and empirical genome drafts. cGOFs show species specificity, and the symmetry of multisegmental cGOFs is conserved among taxa and constrained by DNA polymerase-centric strand-biased gene distribution. The definition of species-specific cGOFs provides powerful guidance for genome assembly and other structure-based analysis. IMPORTANCE Prokaryotic genomes are frequently interrupted by horizontal gene transfer (HGT) and rearrangement. To know whether there is a set of genes not only conserved in position among isolates but also functionally essential for a given species and to further evaluate the stability or flexibility of such genome structures across lineages are of importance. Based on a large number of multi-isolate pangenomic data, our analysis reveals that a subset of core genes is organized into a core-gene-defined genome organizational framework, or cGOF. Furthermore, the lineage-associated cGOFs among Gram-positive and Gram-negative bacteria behave differently: the former, composed of 2 to 4 segments, have their fragments symmetrically rearranged around the origin-terminus axis, whereas the latter show more complex segmentation and are partitioned asymmetrically into chromosomal structures. The definition of cGOFs provides new insights into prokaryotic genome organization and efficient guidance for genome assembly and analysis.

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Migration of Escherichia coli and Klebsiella pneumoniae Carbapenemase (KPC)-Producing Enterobacter cloacae through Wastewater Pipework and Establishment in Hospital Sink Waste Traps in a Laboratory Model System

Microorganisms ◽

10.3390/microorganisms9091868 ◽

2021 ◽

Vol 9 (9) ◽

pp. 1868

Author(s):

Paz Aranega-Bou ◽

Nicholas Ellaby ◽

Matthew J. Ellington ◽

Ginny Moore

Keyword(s):

Escherichia Coli ◽

Enterobacter Cloacae ◽

Model System ◽

Hospital Environment ◽

Laboratory Model ◽

Gram Negative Bacteria ◽

Drug Resistant ◽

Gram Negative ◽

Klebsiella Pneumoniae Carbapenemase ◽

Before And After

Sink waste traps and drains are a reservoir for multi-drug resistant Gram-negative bacteria in the hospital environment. It has been suggested that these bacteria can migrate through hospital plumbing. Hospital waste traps were installed in a laboratory model system where sinks were connected through a common wastewater pipe. Enterobacterales populations were monitored using selective culture, MALDI-TOF identification and antibiotic resistance profiling before and after a wastewater backflow event. When transfer between sinks was suspected, isolates were compared using whole-genome sequencing. Immediately after the wastewater backflow, two KPC-producing Enterobacter cloacae were recovered from a waste trap in which Carbapenemase-producing Enterobacterales (CPE) had not been detected previously. The isolates belonged to ST501 and ST31 and were genetically indistinguishable to those colonising sinks elsewhere in the system. Following inter-sink transfer, KPC-producing E. cloacae ST501 successfully integrated into the microbiome of the recipient sink and was detected in the waste trap water at least five months after the backflow event. Seven weeks and three months after the backflow, other inter-sink transfers involving Escherichia coli ST5295 and KPC-producing E. cloacae ST501 were also observed.

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Migration of Escherichia coli and Klebsiella pneumoniae Carbapenemase (KPC)-Producing Enterobacter cloacae through Wastewater Pipework and Establishment in Hospital Sink Waste Traps in a Laboratory Model System

10.20944/preprints202107.0236.v1 ◽

2021 ◽

Author(s):

Paz Aranega-Bou ◽

Nicholas Ellaby ◽

Matthew J. Ellington ◽

Ginny Moore

Keyword(s):

Escherichia Coli ◽

Enterobacter Cloacae ◽

Model System ◽

Hospital Environment ◽

Laboratory Model ◽

Whole Genome ◽

Gram Negative Bacteria ◽

Drug Resistant ◽

Gram Negative ◽

Before And After

Sink waste traps and drains are a reservoir for multi-drug resistant Gram-negative bacteria in the hospital environment. It has been suggested that these bacteria can migrate through hospital plumbing. Hospital waste traps were installed in a laboratory model system where sinks were connected through a common wastewater pipe. Enterobacterales populations were monitored using selective culture, MALDI-TOF identification and antibiotic resistance profiling before and after a wastewater backflow event. When transfer between sinks was suspected, isolates were compared using whole-genome sequencing. Immediately after the wastewater backflow, two KPC-producing Enterobacter cloacae were recovered from a waste trap in which Carbapenemase-producing Enterobacterales (CPE) had not been detected previously. The isolates belonged to ST501 and ST31 and were genetically indistinguishable to those colonising sinks elsewhere in the system. Following inter-sink transfer, KPC-producing E. cloacae ST501 successfully integrated into the microbiome of the recipient sink and was detected in the waste trap water at least six months after the backflow event. Seven weeks and three months after the backflow, other inter-sink transfers involving Escherichia coli ST5295 and KPC-producing E. cloacae ST501 were also observed.

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Stability of Meropenem and Piperacillin/Tazobactam with Heparin in Various Peritoneal Dialysis Solutions

Peritoneal Dialysis International ◽

10.3747/pdi.2017.00274 ◽

2018 ◽

Vol 38 (6) ◽

pp. 430-440

Author(s):

Karryl Mendes ◽

Harmanjeet Harmanjeet ◽

Mohammed Sedeeq ◽

Ankit Modi ◽

Troy Wanandy ◽

...

Keyword(s):

Peritoneal Dialysis ◽

High Performance ◽

Color Change ◽

Anticoagulant Activity ◽

Storage Conditions ◽

Gram Negative Bacteria ◽

Ph Change ◽

Gram Negative ◽

Extended Spectrum Beta Lactamase ◽

The Stability

Background Infections caused by ceftazidime-resistant Pseudomonas and extended-spectrum beta-lactamase (ESBL)-producing gram-negative bacteria are increasing worldwide. Meropenem and piperacillin/tazobactam (PIP/TZB) are recommended for the treatment of peritoneal dialysis-associated peritonitis (PDAP) caused by ceftazidime-resistant Pseudomonas and other resistant gram-negative bacteria. Patients may also receive intraperitoneal heparin to prevent occlusion of their catheters. However, the stability of meropenem or PIP/TZB, in combination with heparin, in different types of peritoneal dialysis (PD) solutions used in clinical practice is currently unknown. Therefore, we investigated the stability of meropenem and PIP/TZB, each in combination with heparin, in different PD solutions. Methods A total of 15 PD bags (3 bags for each type of PD solution) containing meropenem and heparin and 24 PD bags (3 bags for each type of PD solution) containing PIP/TZB and heparin were prepared and stored at 4°C for 168 hours. The same bags were stored at 25°C for 3 hours followed by 10 hours at 37°C. An aliquot withdrawn before storage and at defined time points was analyzed for the concentration of meropenem, PIP, TZB, and heparin using high-performance liquid chromatography. Samples were also analysed for particle content, pH and color change, and the anticoagulant activity of heparin. Results Meropenem and heparin retained more than 90% of their initial concentration in 4 out of 5 types of PD solutions when stored at 4°C for 168 hours, followed by storage at 25°C for 3 hours and then at 37°C for 10 hours. Piperacillin/tazobactam and heparin were found to be stable in all 8 types of PD solutions when stored under the same conditions. Heparin retained more than 98% of its initial anticoagulant activity throughout the study period. No evidence of particle formation, color change, or pH change was observed at any time under the storage conditions employed in the study. Conclusions This study provides clinically important information on the stability of meropenem and PIP/TZB, each in combination with heparin, in different PD solutions. The use of meropenem-heparin admixed in pH-neutral PD solutions for the treatment of PDAP should be avoided, given the observed sub-optimal stability of meropenem.

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Synthesis and Antimicrobial Activity of Bis-4,6-sulfonamidated 5,7-Dinitrobenzofuroxans

Journal of Chemistry ◽

10.1155/2014/367351 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 6

Author(s):

Irina V. Galkina ◽

Elena V. Tudriy ◽

Yuliya V. Bakhtiyarova ◽

Luiza M. Usupova ◽

Marina P. Shulaeva ◽

...

Keyword(s):

Antimicrobial Activity ◽

Pathogenic Fungus ◽

Fungal Strain ◽

Diffusion Method ◽

Gram Negative Bacteria ◽

Disk Diffusion Method ◽

Gram Negative ◽

Gram Positive Bacteria ◽

The Stability

A new series of bis-4,6-sulfonamidated 5,7-dinitrbenzofuroxans 7–11had been synthesized and tested for antimicrobial activity. The structures of new sulfanilamide derivatives were characterized by elemental analysis, IR spectroscopy, and mass spectrometry (MALDITOF). The synthesized compounds were tested for theirin vitroantimicrobial activity using the disk diffusion method against Gram-positive bacteriaStaphylococcus aureus; the Gram-negative bacteriaEscherichia coli, Pseudomonas aeruginosa, andProteus mirabilis; the fungal strainAspergillus niger; and the yeast-like pathogenic fungusCandida albicans. Our results indicate that the compounds7–11exhibit potent antimicrobial activity. The stability of the compounds was evaluated by TG and DSC methods.

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