Nosocomial infections due to multidrug-resistant bacteria in cancer patients: a six-year retrospective study of an oncology Center in Western China

BACKGROUND

Bacterial infections are the most frequent complications in patients with malignancy, and the epidemiology of nosocomial infections among cancer patients has changed over time. This study aimed to evaluate the characteristics, antibiotic resistance patterns, and prognosis of nosocomial infections due to multidrug-resistant (MDR) bacteria in cancer patients.

METHODS

This retrospective observational study analyzed cancer patients with nosocomial infections caused by MDR from August 2013 to May 2019. The extracted clinical data were recorded in a standardized form and compared based on the survival status of the patients after infection and during hospitalization. The data were analyzed using independent samples t-test, Chi-square test, and binary logistic regression. P-values < 0.05 were considered significant.

RESULTS

One thousand eight patients developed nosocomial infections during hospitalization, with MDR strains detected in 257 patients. Urinary tract infection (38.1%), respiratory tract infection (26.8%), and bloodstream infection (BSI) (12.5%) were the most common infection types. Extended-spectrum β-lactamase producing Enterobacteriaceae (ESBL-PE) (72.8%) members were the most frequently isolated MDR strains, followed by Acinetobacter baumannii (11.7%), and Stenotrophomonas maltophilia (6.2%). The results of multivariate regression analysis revealed that smoking history, intrapleural/abdominal infusion history within 30 days, the presence of an indwelling urinary catheter, length of hospitalization, and hemoglobin were independent factors for in-hospital mortality in the study population. The isolated MDR bacteria exhibited high rates of sensitivity to amikacin, meropenem, and imipenem.

CONCLUSIONS

The burden of nosocomial infections due to MDR bacteria is considerably high in oncological patients, with ESBL-PE being the most predominant causative pathogen. Our findings suggest that amikacin and carbapenems actively against more than 89.7% of MDR isolates. The precise management of MDR bacterial infections in cancer patients may improve the prognosis of these individuals.

High proportion of multidrug-resistant organisms in children hospitalized abroad

Our infection control team initiated active screening for multidrug-resistant organisms (MDROs) among children who had been hospitalized abroad before their admission to our hospital. MDROs were detected in 19 of 34 cases (56%), including 3 isolates of Enterobacteriaceae harboring carbapenemase genes still rare in Japan. Early recognition of MDROs by screening this population may be required to avoid the introduction of new modes of resistance into the hospital environment.

Discovery and Development of Gaseous Nitric Oxide Under Increased Atmospheric Pressure as an Antimicrobial: In Vitro and In Vivo Testing of Nitric Oxide Against Multidrug-Resistant Organisms

Gaseous nitric oxide under increased atmospheric pressure (gNOp) has shown ability to kill multidrug-resistant bacteria in an in vitro model and in a live mammalian (porcine) model. Factors impacting the kill rate of the multidrug-resistant bacteria include atmospheric pressures, concentration of gaseous NO, flow rate, and duration of application. Using successful in vitro parameters, gNOp showed multilog reduction of bacteria in a live mammalian (porcine) model. The in vitro testing system, using the EpiDerm-FT skin model (stem cell grown skin), was used to develop an infected wound model for Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus, and methicillin-resistant S aureus.

Multidrug-Resistant Staphylococcus epidermidis Ventriculostomy-Related Infection Successfully Treated by Intravenous Ceftaroline after Failure of Daptomycin Treatment

BACKGROUND

Ventriculostomy-related infection with multidrug-negative strains are challenging to treat. We report the use of new antibiotics in such a case.

CASE DESCRIPTION

We report the case of a neurosurgical intensive care unit patient who developed ventriculostomy-related infection with a multidrug-resistant Staphylococcus epidermidis. Vancomycin, recommended in such cases, was not used due to high minimal inhibitory concentrations and concerns for lack of pharmacokinetic/pharmacodynamic target attainment. Daptomycin and ceftaroline remained the only treatment options. Daptomycin was shown microbiologically ineffective after 10 treatment days, with undetectable cerebrospinal fluid (CSF) concentration. Ceftaroline, a novel beta-lactam agent to which the strain showed susceptibility, was thus used. Serum and CSF samples were assessed for antibiotic concentrations. Our results show that CSF bacterial clearance was obtained after 6 days of such treatment. Serum and CSF samplings showed low penetration ratios (2.6%-4.8%), probably due to mild inflammatory CSF profile, with CSF concentration at minimal inhibitory concentration level.

CONCLUSIONS

We observed than even in the case of mild meningeal inflammation, ceftaroline penetration in CSF, although moderate, enabled efficient bacterial clearance and clinical efficacy, in adjunction to correct ventriculoperitoneal shunt management.

Evaluation of antibacterial and enhancement of antibiotic action by the flavonoid kaempferol 7-O-β-D-(6″-O-cumaroyl)-glucopyranoside isolated from Croton piauhiensis müll

There has been a rapid increase in the incidence and prevalence of opportunistic bacterial infections. Inappropriate use of current antibiotics has continuously contributed to the emergence of resistance to conventional antibiotic therapy. Therefore, the search for natural molecules that are able to combat infections is of great public interest, and many of these compounds with antimicrobial properties can be obtained from phytochemical studies of medicinal plants. In this context, this study reports the isolation and characterization of the flavonoid, kaempferol 7-O-β-D-(6″-O-cumaroyl)-glucopyranoside, from Croton piauhiensis leaves. Additionally, the intrinsic antimicrobial action of the compound and its enhancement against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus strains were assessed. The minimum inhibitory concentration (MIC) of the compound was determined using broth microdilution assays. To evaluate the modulatory effect of the flavonoid, the MIC of antibiotics amikacin and gentamicin, belonging to the class aminoglycosides was assessed, with and without the compound in sterile microplates. The results of intrinsic antibacterial activity tests revealed that the compound had no antibacterial activity against strains tested at concentrations <1024 μg/mL. The combination of the flavonoid at a concentration of 128 μg/mL with gentamicin presented synergistic effects against S. aureus 10 and E. coli 06, and also reduced the MIC from 16 μg/mL to 4 μg/mL and 8 μg/mL, respectively. Amikacin also showed synergistic effects against S. aureus 10 and E. coli 06. We also observed reduced MIC for both, from 128 μg/mL to 32 μg/mL; however, antagonism for P. aeruginosa increased the MIC from 16 μg/mL to 64 μg/mL. The combination of the flavonoid with the aminoglycosides may be an alternative to potentiate the expected results in treatment against S. aureus and E. coli, since their association leads to a synergistic effect, reducing the MIC of these drugs and decreasing the dose necessary for therapeutic success.

Greater optimisation of pharmacokinetic/pharmacodynamic parameters through a loading dose of intravenous colistin in paediatric patients

Use of colistin in children is rising in line with the increase of multidrug-resistant Gram-negative bacteria (MDR-GNB). In adults, a colistin loading dose is recommended to achieve therapeutic concentrations within 12-24 h. Here we aimed to describe the pharmacokinetic (PK) parameters of a loading dose versus a recommended initial dose of intravenous colistimethate sodium (CMS) in paediatric patients. A prospective, open-label, PK study was conducted in paediatric patients (age 2-18 years) with normal renal function. Patients (n = 20) were randomly assigned to receive either a CMS loading dose (LD group) of 4 mg of colistin base activity (CBA)/kg/dose or a standard initial dose (NLD group) of 2.5 mg (12-h interval) or 1.7 mg (8-h interval) of CBA/kg/dose. Serial blood samples were collected. Plasma concentrations of formed colistin were measured by LC-MS/MS. PK parameters were reported. Acute kidney injury (AKI) was monitored by serum creatinine and urine NGAL. The median (interquartile range) age and body weight were 8.5 (3.5-11.3) years and 21.5 (13.5-20.0) kg. The mean (standard deviation) of first-dose PK parameters of the LD group versus the NLD group were: C_max, 6.1 (2.4) vs. 4.1 (1.3) mg/L; AUC_0-t, 26.5 (12.5) vs. 13.5 (3.6) mg/L·h; V_d, 0.7 (0.4) vs. 0.6 (0.3) L/kg; and t_1/2, 2.9 (0.6) vs. 2.6 (0.4) h. No patient developed AKI by serum creatinine criteria. A CMS loading dose is beneficial for improvement of colistin exposure without increased AKI. A higher daily dose of CMS should be considered, especially for MDR-GNB treatment.

Prospective multicentre study of rectal carriage of multidrug-resistant Enterobacteriaceae among health-care workers in Spain

OBJECTIVES

To investigate the rectal carriage of multidrug-resistant Enterobacteriaceae (colistin-resistant, extended-spectrum β-lactamase (ESBL) -producers and/or carbapenemase-producers) among health-care workers (HCWs) from six Spanish hospitals.

METHODS

Rectal swabs from 258 HCWs, employed in intensive care units, haematology wards and clinical microbiology laboratories from six hospitals in northern Spain were studied. They were cultured in selective media for Gram-negative resistant bacteria. Detection of antimicrobial resistance genes and multilocus sequence typing were performed by PCR and further sequencing. A questionnaire including data related to risk factors of colonization/infection by resistant bacteria (age, gender, chronic diseases, immunosuppressive therapies, invasive procedures or antimicrobial treatments) was given to each participant.

RESULTS

No carbapenemase-producing Enterobacteriaceae were recovered. However, 8/258 HCWs (3.1%) were positive for ESBL-producing isolates. This rate was not higher than the colonization rate previously reported in Spain for healthy people in the community. Five isolates showed high-level resistance to colistin (MICs ranging from 8 to 128 mg/L) but all of them were negative for the mcr genes tested. No statistically significant risk factors for gut colonization by ESBL-producing or colistin-resistant Enterobacteriaceae were identified among the HCWs participating in the study.

CONCLUSIONS

Our data suggest that working in hospitals does not represent a risk for rectal carriage of multidrug-resistant Enterobacteriaceae.

Bacteriophage Therapy Increases Complement-Mediated Lysis of Bacteria and Enhances Bacterial Clearance After Acute Lung Infection With Multidrug-Resistant Pseudomonas aeruginosa

Emergence of multidrug-resistant (MDR) bacterial infections is a major problem in clinical medicine. Development of new strategies such as phage therapy may be a novel approach for treatment of life-threatening infections caused by MDR bacteria. A newly isolated phage, MMI-Ps1, with strong lytic activity was used for treatment of acute lung infection with Pseudomonas aeruginosa in a mouse model. Intranasal administration of a single dose of MMI-Ps1 immediately after infection provided a significant level of protection and increased the survival duration. Moreover, treatment of infected mice with phage as late as 12 hours after infection was still protective. Our in vitro results are the first to show the synergistic elimination of serum-resistant Pseudomonas strains by phage and complement. Phage therapy increases the efficacy of complement-mediated lysis of serum-resistant P. aeruginosa strains, indicating the importance of an intact complement system in clearing Pseudomonas infection during phage therapy.

New antibiotics for the treatment of infections by multidrug-resistant microorganisms

One of the current priorities of the World Health Organization is multidrug-resistant bacteria, because they are a global problem due to their rapid spread and the difficulty of their treatment. In addition, they are associated with high morbidity, mortality and high economic costs. There are multidrug-resistant bacteria, both Gram-positive and Gram-negative, including Pseudomonas aeruginosa and Acinetobacter baumannii resistant to carbapenems, enterobacteria producing carbapenemases, Staphylococcus aureus resistant to methicillin and/or with intermediate sensitivity to vancomycin, and Enterococcus faecium (and less frequently Enterococcus faecalis) resistant to vancomycin. This review will comment on the new antibiotics that have been incorporated into the therapeutic arsenal in recent years, as well as other promising antibiotics that are in their final stages of development.

Gold-silver nanoshells promote wound healing from drug-resistant bacteria infection and enable monitoring via surface-enhanced Raman scattering imaging

Chronic infections, caused by multidrug-resistant (MDR) bacteria, constitute a serious problem yet often underappreciated in clinical practice. The in situ monitoring of the bacteria-infected disease is also necessary to track and verify the therapeutic effect. Herein we present a facile approach to overcome the above challenges through a Raman tag 3,3'-diethylthiatricarbocyanine iodide (DTTC)-conjugated gold-silver nanoshells (AuAgNSs). With a strong responsive of the near-infrared laser due to surface plasmon resonance (SPR) from hybrid metallic nanoshell structure, AuAgNSs exhibits an efficient photothermal effect, and it simultaneously releases silver ions during laser irradiation to bacterial eradicate. Herein, two MDR bacteria strain, methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum β-lactamase Escherichia coli, are chosen as models and studied both in vitro and in vivo. As a result, the AuAgNSs-DTTC substrates enable surface-enhanced Raman scattering imaging to provide a non-invasive and extremely high sensitive detection (down to 300 CFU mL^-1 for MRSA) and prolonged tracking (at least 8 days) of residual bacteria. In a chronic MRSA-infected wound mouse model, the AuAgNSs gel-mediated photothermal therapy/silver-release leads to a synergistic would healing with negligible toxicity or collateral damage to vital organs. These results suggest that AuAgNSs-DTTC is a promising anti-bacterial tool for clinical translation.

Antimicrobial activity of certain natural-based plant oils against the antibiotic-resistant acne bacteria

The unceasing emerging of multidrug-resistant bacteria imposes a global foremost human health threat and discovery of new alternative remedies are necessity. The use of plant essential oil in the treatment of many pathogenic bacteria is promising. Acne vulgaris is the most common skin complaint that fears many people about their aesthetic appearance. In this work we investigated the antibacterial activity of some plant oils against acne-inducing bacteria. Three bacterial isolates were identified from Egypt, biochemically and by means of 16s rRNA gene typing, and were designated as Staphylococcus aureus EG-AE1, Staphylococcus epidermidis EG-AE2 and Cutibacterium acnes EG-AE1. Antibiotic susceptibility test showed resistance of the isolates to at least six antibiotics, yet they are still susceptible to the last resort Vancomycin. In vitro investigations of eleven Egyptian plant oils, identified tea tree and rosemary oils to exhibit antibacterial activity against the antibiotic-resistant acne isolates. Inhibition zones of 15 ± 0.5, 21.02 ± 0.73 and 20.85 ± 0.76 mm was detected when tea tree oil applied against the above-mentioned bacteria respectively, while inhibition zones of 12.5 ± 1.5, 15.18 ± 0.38 and 14.77 ± 0.35 mm were detected by rosemary oils. Tea tree and rosemary oils exhibited bacteriostatic and bactericidal activity against all the strains with MICs/MBCs ranging between 39-78 mg/L for tea tree oil and 39-156 mg/L for rosemary oil. All the isolates were killed after 4 and 6 h upon growing with 200 mg/L of tea tree and rosemary oils, respectively. Additionally, gas chromatography mass spectrometry (GC/MS) profiling identified and detected a variable number of antimicrobial compounds in both oils.

Factors associated with treatment failure after advice from infectious disease specialists

OBJECTIVE

Risk factors associated with treatment failure after the infectious disease specialist's (IDS) advice remain unknown. We aimed to identify these risk factors.

METHODS

We included patients hospitalized in our tertiary care center who consulted an infectious disease specialist between January 2013 and April 2015. Treatment failure was defined by a composite criterion: signs of sepsis beyond Day 3, ICU admission, or death. Treatment success was defined by the patient's sustained clinical improvement.

RESULTS

A total of 240 IDS recommendations were made. Diagnosis was changed for 64 patients (26.7%) and 50 patients experienced treatment failure after the IDS advice. In multivariate analysis, compliance with the IDS advice was associated with a higher rate of success (OR=0.09, 95%CI [0.01-0.67]). Variables associated with treatment failure in the multivariate analysis were Charlson comorbidity score at admission (OR=1.24, 95%CI [1.03-1.50]), a history of infection or colonization with multidrug-resistant bacteria (OR=8.27, 95%CI [1.37-49.80]), and deterioration of the patient's status three days after the IDS advice (OR=12.50, 95%CI [3.16-49.46]).

CONCLUSION

Reassessing IDS recommendations could be interesting for specific patients to further adapt and improve them.

Colistin versus meropenem in the empirical treatment of ventilator-associated pneumonia (Magic Bullet study): an investigator-driven, open-label, randomized, noninferiority controlled trial

BACKGROUND

Colistin is recommended in the empirical treatment of ventilator-associated pneumonia (VAP) with a high prevalence of carbapenem-resistant gram-negative bacilli (CR-GNB). However, the efficacy and safety of colistin are not well defined.

METHODS

A multicenter prospective randomized trial conducted in 32 European centers compared the efficacy and safety of colistin (4.5 million unit loading dose followed by a maintenance dose of 3 million units every 8 h) versus meropenem (2 g every 8 h), both in combination with levofloxacin (500 mg every 12 h) for 7-14 days in patients with late VAP. Between May 2012 and October 2015, 232 patients were randomly assigned to the 2 treatment groups. The primary endpoint was mortality at 28 days after randomization in the microbiologically modified intention-to-treat (mMITT) population. Secondary outcomes included clinical and microbiological cure, renal function at the end of the treatment, and serious adverse events. The study was interrupted after the interim analysis due to excessive nephrotoxicity in the colistin group; therefore, the sample size was not achieved.

RESULTS

A total of 157 (67.7%) patients were included in the mMITT population, 36 of whom (22.9%) had VAP caused by CR-GNB. In the mMITT population, no significant difference in mortality between the colistin group (19/82, 23.2%) and the meropenem group (19/75, 25.3%) was observed, with a risk difference of - 2.16 (- 15.59 to 11.26, p = 0.377); the noninferiority of colistin was not demonstrated due to early termination and limited number of patients infected by carbapenem-resistant pathogens. Colistin plus levofloxacin increased the incidence of renal failure (40/120, 33.3%, versus 21/112, 18.8%; p = 0.012) and renal replacement therapy (11/120, 9.1%, versus 2/112, 1.8%; p = 0.015).

CONCLUSIONS

This study did not demonstrate the noninferiority of colistin compared with meropenem, both combined with levofloxacin, in terms of efficacy in the empirical treatment of late VAP but demonstrated the greater nephrotoxicity of colistin. These findings do not support the empirical use of colistin for the treatment of late VAP due to early termination.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01292031. Registered 9 February 2011.

[Analysis of the predictive value of preventive isolation criteria in the intensive care unit]

OBJECTIVE

To assess the diagnostic accuracy of the criteria used to detect patients carrying multiresistant microorganisms (MRMs).

DESIGN

A prospective observational study was carried out from May 2014 to May 2015.

SETTING

Polyvalent Intensive Care Unit.

PATIENTS

A cohort of consecutively admitted patients meeting the following criteria for preventive isolation according to the "Zero Resistance" project: hospital length of stay>4 days in the last three months ("hospital"); antibiotherapy during one week in the last month ("antibiotic"); institutionalized patients or recurrent contact with healthcare ("institution or care"); MRM carrier in the last 6 months ("previous MRM").

VARIABLES

Demographic data, culture results and isolation time. A multivariate analysis was performed using multiple logistic regression between each of the risk factors and patient MRM carrier status.

RESULTS

During the study period, 575 patients were admitted, of which 28% met the isolation criteria (162). Fifty-one (31%) were MRM carriers. Of the patients who did not meet the criteria, 29 (7%) were carriers. In the multivariate analysis, the only variable independently associated to carrier status was "previous MRM", with OR=12.14 (95%CI 4.24-34.77).

CONCLUSIONS

The only criterion independently associated with the ability to detect patients with MRMs upon admission to the ICU was the existence of "previous MRM".

Study on the effects of different dimerization positions on biological activity of partial d-Amino acid substitution analogues of Anoplin

Antimicrobial peptides have recently attracted much attention due to their broad-spectrum antimicrobial activity, rapid microbial effects, and minimal tendency toward resistance development. In this study, a series of new C-C terminals and C-N terminals dimer peptides were designed and synthesized by intermolecular dimerization of the partial d-amino acid substitution analogues of Anoplin, and the effects of different dimerization positions on biological activity were researched. The antimicrobial activity and stability of the new C-C terminals and C-N terminals dimer peptides were significantly improved compared with their parent peptide Anoplin. They displayed no obvious hemolytic activity and lower cytotoxicity, with a higher therapeutic index. Furthermore, the new dimer peptides not only enabled to rapidly disrupt bacterial membrane and damage its integrity which was different from conventional antibiotics but also penetrated bacterial membrane into binding to intracellular genomic DNA. More importantly, the new dimer peptides showed excellent antimicrobial activity against multidrug-resistant strains isolated from clinics in contrast to conventional antibiotics with low tendency to develop the bacterial resistance, besides they exhibited better anti-biofilm activity than antibiotic Rifampicin. Interestingly, the C-N terminals dimer peptides were superior to C-C terminals ones in antimicrobial and anti-biofilm activity, therapeutic index, outer membrane permeability, and DNA binding ability, whereas there were no noteworthy effects in different dimerization positions on stability. Thus, these data suggested that dimerization in different positions represented a potent strategy to develop novel antimicrobial agents for fighting against increasing bacterial resistance.

Plant-derived secondary metabolites as the main source of efflux pump inhibitors and methods for identification

The upsurge of multiple drug resistance (MDR) bacteria substantially diminishes the effectiveness of antibiotic arsenal and therefore intensifies the rate of therapeutic failure. The major factor in MDR is efflux pump-mediated resistance. A unique pump can make bacteria withstand a wide range of structurally diverse compounds. Therefore, their inhibition is a promising route to eliminate resistance phenomenon in bacteria. Phytochemicals are excellent alternatives as resistance-modifying agents. They can directly kill bacteria or interact with the crucial events of pathogenicity, thereby decreasing the ability of bacteria to develop resistance. Numerous botanicals display noteworthy efflux pumps inhibitory activities. Edible plants are of growing interest. Likewise, some plant families would be excellent sources of efflux pump inhibitors (EPIs) including Apocynaceae, Berberidaceae, Convolvulaceae, Cucurbitaceae, Fabaceae, Lamiaceae, and Zingiberaceae. Easily applicable methods for screening plant-derived EPIs include checkerboard synergy test, berberine uptake assay and ethidium bromide test. In silico high-throughput virtual detection can be evaluated as a criterion of excluding compounds with efflux substrate-like characteristics, thereby improving the selection process and extending the identification of EPIs. To ascertain the efflux activity inhibition, real-time PCR and quantitative mass spectrometry can be applied. This review emphasizes on efflux pumps and their roles in transmitting bacterial resistance and an update plant-derived EPIs and strategies for identification.

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Active efflux as the main resistance strategy in bacteria.

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Phytochemicals as promising alternatives against efflux pumps-mediated MDR.

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Herbals-based efflux pump inhibitors screening, the methods.

Efficacy and safety of fecal microbiota transplantation for decolonization of intestinal multidrug-resistant microorganism carriage: beyond Clostridioides difficile infection

Persistent reservoirs of multidrug-resistant microorganisms (MDRO) that are prevalent in hospital settings and communities can lead to the spread of MDRO. Currently, there are no effective decolonization strategies, especially non-pharmacological strategies without antibiotic regimens. Our aim was to evaluate the efficacy and safety of fecal microbiota transplantation (FMT) for the eradication of MDRO. A systematic literature search was performed to identify studies on the use of FMT for the decolonization of MDRO. PubMed, EMBASE, Web of Science, and Cochrane Library were searched from inception through January 2019. Of the 1395 articles identified, 20 studies met the inclusion and exclusion criteria. Overall, the efficacy of FMT for the eradication of each MDRO was 70.3% (102/146) in 121 patients from the 20 articles. The efficacy rates were 68.2% (30/44) for gram-positive bacteria and 70.6% (72/102) for gram-negative bacteria. Minor adverse events, including vomiting, diarrhea, abdominal pain, and ileus, were reported in patients who received FMT. FMT could be a promising strategy to eradicate MDRO in patients. Further studies are needed to confirm these findings and establish a comprehensive FMT protocol for standardized treatment.Key messagesThe development of new antibiotics lags behind the emergence of multidrug-resistant microorganisms (MDRO). New strategies are needed.Theoretically, fecal microbiota transplantation (FMT) might recover the diversity and function of commensal microbiota from dysbiosis in MDRO carriers and help restore colonization resistance to pathogens.A literature review indicated that FMT could be a promising strategy to eradicate MDRO in patients.

[Multidrug-resistant bacteria detection in patients undergoing allogeneic hematopoietic cell transplantation: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

The Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) organizes annual workshops in the attempt to harmonize clinical practices among different francophone transplantation centers. Here we report our recommendations regarding detection of the multidrug-resistant bacteria in hematology.

Chlorhexidine-based decolonization to reduce healthcare-associated infections and multidrug-resistant organisms (MDROs): who, what, where, when, and why?

Body surface decolonization with chlorhexidine bathing and nasal mupirocin has become a simple solution for prevention of healthcare-associated infections. The clinical trial evidence for this practice will be reviewed to understand who benefits from this practice, for what reasons, and at what times. The method of bathing and nasal decolonization will also be discussed as proper application is needed for maximal effectiveness. Finally, the conflict between current effectiveness and future potential for fueling resistance is considered.

Pitfalls and Unexpected Benefits of an Electronic Hand Hygiene Monitoring System

BACKGROUND

No single strategy is more effective than proper hand hygiene (HH) in reducing the spread of nosocomial infections. Unfortunately, health care worker compliance with HH is imperfect. We sought to improve HH compliance using an electronic hand hygiene monitoring system (EHHMS) in 2 units to collect unbiased data and provide feedback.

METHODS

In this prospective, quasi-experimental study, the Hyginex EHHMS was installed in 2 units at Tufts Medical Center. Ninety-one bracelets were assigned, and electronic data were collected over 8 months. Human observations continued. We compared HH compliance as measured by human observation before, during, and after EHHMS implementation. Pre- and post-implementation surveys were distributed to staff.

RESULTS

The number of electronically captured HH compliance observations was small due to infrequent bracelet use after month 2 of the intervention. HH compliance, as determined by human observation, increased by an average of 1.3 percentage points per month (P = .0005). Survey responses revealed negative attitudes about the EHHMS before and after its implementation.

CONCLUSIONS

Despite poor EHHMS participation and negative attitudes toward its implementation, HH compliance, as measured by human observation, significantly improved. Hospitals considering implementing an EHHMS should look to refine the intervention to encourage health care worker participation.

Incidence and costs of ventilator-associated pneumonia in the adult intensive care unit of a tertiary referral hospital in Mexico

BACKGROUND

Ventilator-associated pneumonia (VAP) is defined as pneumonia that occurs after 48 hours of endotracheal intubation and initiation of mechanical ventilation. The aim of this work was to use a micro-costing method to calculate the costs generated in 2017 for the care of patients with VAP at the Hospital Juárez de México.

METHODS

We performed a cross-sectional, retrospective, analytical, and observational study of the databases of the registry of health care-associated infections (HAIs) in 2017, in addition to a micro-costing study.

RESULTS

We studied 48 VAP cases in an adult intensive care unit (AICU). In this period, 1668 ventilator days were identified, with an incidence rate of 28.8 per 1000 days. All cases were caused by multidrug-resistant (MDR) bacteria and the costs of their care exceeded the average costs for the use of antimicrobials. By calculating the profit on return as an association measure, we found that VAP caused by MDR bacteria confers 9 times the risk of increasing the costs of care above the expected average.

CONCLUSIONS

The cost for a case of VAP in the AICU is high and has an impact on the institutional budget. Control measures to prevent the spread of bacteria, particularly MDR bacteria, must be put into place in order to avoid increases in hospital stay costs and mortality.

Perioperative prophylaxis with ertapenem reduced infections caused by extended-spectrum betalactamase-producting Enterobacteriaceae after kidney transplantation

Backgound

In recent years we have witnessed an increase in infections due to multidrug-resistant organisms in kidney transplant recipients (KTR). In our setting, we have observed a dramatic increase in infections caused by extended-spectrum betalactamase-producing (ESBL) Enterobacteriaceae in KTR. In 2014 we changed surgical prophylaxis from Cefazolin 2 g to Ertapenem 1 g.

Methods

We compared bacterial infections and their resistance phenotype during the first post-transplant month with an historical cohort collected during 2013 that had received Cefazolin.

Results

During the study period 110 patients received prophylaxis with Cefazolin and 113 with Ertapenem. In the Ertapenem cohort we observed a non-statistically significant decrease in the percentage of early bacterial infection from 57 to 47%, with urine being the most frequent source in both. The frequency of infections caused by Enterobacteriaceae spp. decreased from 64% in the Cefazolin cohort to 36% in the Ertapenem cohort (p = 0.005). In addition, percentage of ESBL-producing strains decreased from 21 to 8% of all Enterobacteriaceae isolated (p = 0.015). After adjusted in multivariate Cox regression analysis, male sex (HR 0.16, 95%CI: 0.03–0.75), cefazolin prophylaxis (HR 4.7, 95% CI: 1.1–22.6) and acute rejection (HR 14.5, 95% CI: 1.3–162) were associated to ESBL- producing Enterobacteriaceae infection.

Conclusions

Perioperative antimicrobial prophylaxis with a single dose of Ertapenem in kidney transplant recipients reduced the incidence of early infections due to ESBL-producing Enterobacteriaceae without increasing the incidence of other multidrug-resistant microorganisms or C. difficile.

Treatment of antibiotic-resistant bacteria by encapsulation of ZnO nanoparticles in an alginate biopolymer: Insights into treatment mechanisms

Treating multidrug-resistant bacteria has been a challenging task, although the bacteria have been reported as a trace contaminant present in tap water. Given emerging issues on antibiotic-resistant bacteria, the present study investigated a novel treatment method in which ZnO nanoparticles (NPs) are encapsulated in an alginate biopolymer solution to explore primary antibacterial mechanisms. The antibacterial effects of this technology on two model antibiotic-resistant bacteria (Escherichia coli DH5-α and Pseudomonas aeruginosa) were found to be highly effective, with the removal rates of 98% and 88%, respectively, at the initial bacteria concentration of 10⁸ CFU mL^-1 over 6 h. The inactivation of antibiotic-resistant bacteria by ZnO NP-alginate beads was improved by increasing the nanocomposite amount (4, 10, and 20 mg) and contact time. The primary mechanism involved the generation of reactive oxygen species (ROS). The ZnO NP-alginate beads were demonstrated to be highly promising for different applications in water treatment, especially for point-of-use in the perspectives of reusability, antibacterial property of ZnO, immobilizing NPs, and utilizing high surface area of NPs, with a slight release of zinc ions.

Antibiotic hypersensitivity in MRSA induced by special protein aggregates

Emergence of multidrug-resistant bacteria is a major global concern. According to WHO, methicillin-resistant Staphylococcus aureus (MRSA) is a threatening pathogen resistant to a wide spectrum of antibiotics. Herein, to overcome drug resistance in MRSA, we successfully integrated traditional antibacterial methods but with a novel trick that included use of hen egg-white lysozyme's special aggregates generated by fibrillization. The minimum inhibitory concentration of oxacillin (Ox) for MRSA declined from 600 μM to <20 μM when using aggregates. Scanning and transition electron micrographs showed completely disrupted cells when treated with aggregated protein/Ox (20 μM). The assisting role of aggregates to induce antibiotic hypersensitivity was continuous and stable, but sub-inhibitory antibiotic concentration (20 μM) was required again after 8 h. Investigations regarding mechanism of antibiotic hypersensitivity revealed that aggregates were oligomers but not mature fibrils. Furthermore, reactive oxygen species levels rose significantly after treating bacteria with aggregated protein/Ox. Study of resistance mechanisms indicated that in response to wall structure alterations, mecA expression dropped significantly in the presence of aggregated protein/Ox (20 μM) relative to Ox (20 μM). This observation can be a breakthrough in finding alternatives where antibiotic dosage can be significantly reduced, thereby preventing emergence of new multidrug-resistant bacteria.

Perceived differences between intensivists and infectious diseases consultants facing antimicrobial resistance: a global cross-sectional survey

To identify differences in perception on multi-drug-resistant (MDR) organisms and their management at intensive care units (ICU). A cross-sectional survey was conducted. A proposal addressing a pathogen priority list (PPL) for ICU, arising from the TOTEM study, was compared with a sample of global experts in infections in critically ill patients. The survey was responded by 129 experts. Globally, ESBL Enterobacteriaceae, followed by carbapenem-resistant Acinetobacter baumannii and carbapenem-resistant Klebsiella pneumoniae, were the main concerns. Some differences in opinion were identified between 63 (49%) ICU physicians (ICU/anesthesiology) and 43 (33%) infectious disease consultants (ID physicians/microbiologists). The pathogens most concerning in the ICU for intensivists were ESBL Enterobacteriaceae (38%) versus carbapenem-resistant A. baumannii (48.3%) for ID consultants, (p < 0.05). Increasing number of ID consultants over intensivists (26% vs 14%) reported difficulty in choosing initial therapy for carbapenem-resistant A. baumannii. For intensivists, the urgent measures to limit development of antibiotic resistance were headed by cohort measures (26.3%) versus increasing nurse/patient ratio (32.5%) for ID consultants, (p < 0.05). Regarding effectiveness to prevent MDR development and spread, education programs (42.4%) were the priority for intensivists versus external consultation (35.7%) for ID consultants. Finally, both groups agreed that carbapenem resistance was the most pressing concern (> 70%) regarding emerging resistance. Differences in priorities regarding organisms, infection control practices, and educational priorities were visualized between ID/clinical microbiologists and ICU/anesthesiologists. Multi-disciplinary collaboration is required to achieve best care for ICU patients with severe infections.

Antibiotic stewardship: ripartiamo dalla pratica clinica

Antibiotic stewardship: a milestone in everyday clinical practice Infectious diseases caused by multi-resistant pathogens are increasing worldwide and are challenging for clinicians, also in urological setting. The alarming situation is worsened by the limited perspective of new antibiotic developments. Several authors demonstrated that in Italy we have alarming data about resistance rates: in Campania about 58% of Escherichia coli are resistant to fluroquinolones, as 46% to sulfamethoxazole-trimethoprim. On the other hand, the resistance rate against fosfomycin is still low less than 5%. More alarming data are reported about Klebsiella pneumoniae: resistance rate to flurquinolones 65% and 58% to sulfamethoxazole-trimethoprim. A continuing uncritical, non-guideline-conform and overuse of antibiotics leads to selection of multidrug-resistant pathogens, which can colonize patients and make the treatment a real challenge. A revision of our approach to urinary tract infections at the light of antibiotic stewardiship principles are urgently required, in particular starting from the everyday clinical practice.

New Antibiotics for Pneumonia

Delayed antimicrobial prescriptions and inappropriate treatment can lead to poor outcomes in pneumonia. In nosocomial infections, especially in countries reporting high rates of antimicrobial resistance, the presence of multidrug-resistant gram-negative and gam-positive bacteria can limit options for adequate antimicrobial treatment. New antibiotics, belonging to known classes of antimicrobials or characterized by novel mechanisms of actions, have recently been approved or are under development. Advantages of the new compounds include enhanced spectrum of activity against resistant bacteria, high lung penetration, good tolerability, and possibility for intravenous to oral sequential therapy. This article reviews characteristics of newly approved and investigational compounds.

BOCS: DNA k-mer content and scoring for rapid genetic biomarker identification at low coverage

A single, inexpensive diagnostic test capable of rapidly identifying a wide range of genetic biomarkers would prove invaluable in precision medicine. Previous work has demonstrated the potential for high-throughput, label-free detection of A-G-C-T content in DNA k-mers, providing an alternative to single-letter sequencing while also having inherent lossy data compression and massively parallel data acquisition. Here, we apply a new bioinformatics algorithm - block optical content scoring (BOCS) - capable of using the high-throughput content k-mers for rapid, broad-spectrum identification of genetic biomarkers. BOCS uses content-based sequence alignment for probabilistic mapping of k-mer contents to gene sequences within a biomarker database, resulting in a probability ranking of genes on a content score. Simulations of the BOCS algorithm reveal high accuracy for identification of single antibiotic resistance genes, even in the presence of significant sequencing errors (100% accuracy for no sequencing errors, and >90% accuracy for sequencing errors at 20%), and at well below full coverage of the genes. Simulations for detecting multiple resistance genes within a methicillin-resistant Staphylococcus aureus (MRSA) strain showed 100% accuracy at an average gene coverage of merely 0.515, when the k-mer lengths were variable and with 4% sequencing error within the k-mer blocks. Extension of BOCS to cancer and other genetic diseases met or exceeded the results for resistance genes. Combined with a high-throughput content-based sequencing technique, the BOCS algorithm potentiates a test capable of rapid diagnosis and profiling of genetic biomarkers ranging from antibiotic resistance to cancer and other genetic diseases.

Impact of an Acinetobacter baumannii outbreak on kidney events in a burn unit: A targeted machine learning analysis

BACKGROUND

Multidrug-resistant (MDR) bacteria outbreaks represent a major threat in intensive care units. Patients may then be exposed to drug-related direct toxicity during such outbreaks. The objective of this study was to explore the impact of an outbreak of imipenem-resistant Acinetobacter baumannii (IR-AB) on renal outcomes.

METHODS

We performed a before-and-after observational study in a French burn intensive care unit during an IR-AB outbreak: a 13-month period before (period A, October 2013-October 2014) and a 13-month period after outbreak control (period B, December 2014-December 2015). A total of 409 patients were included, 195 during period A and 214 during period B. The main endpoint was major adverse kidney events at day 90 (MAKE 90). Secondary endpoints were acute kidney injury (AKI) and persistent renal dysfunction.

RESULTS

Incidence of MAKE 90 was 15.9% during period A versus 11.2% during period B (P = .166) and AKI 28.2% versus 18.7% (P = .023). The use of colistin was associated with renal outcomes in univariate analysis. After adjustment of potential confounding factors using a targeted Machine Learning Analysis (ie, IR-AB-related infection, septic shock, severity scores, other nephrotoxics, chronic kidney disease, serum creatinine at admission, Staphylococcus aureus), colistin remained associated with the risk of MAKE and AKI (relative risk = 2.909, 95% confidence interval [CI] [1.364, 6.204], P = .006 for MAKE 90, and relative risk = 2.14, 95% CI [1.52, 3.02], P<.0001 for AKI).

CONCLUSIONS

The episode of IR-AB outbreak was associated with an increased risk of kidney events, which appears to be driven by the use of colistin.

Urinary tract infections in patients with neurogenic bladder

Urinary tract infections (UTIs) in patients with neurogenic bladder are a major public health issue due to their high incidence and major consequences. Despite their frequency and potential severity, their physiopathology and management are poorly known. We provide a narrative literature review on the epidemiology, physiopathology, diagnostic criteria, microbiology, antimicrobial management, and prevention. UTIs among patients with neurogenic bladder are associated with high morbidity and healthcare utilization. Risk factors for UTI among this population are: indwelling catheter, urinary stasis, high bladder pressure, and bladder stones. Their diagnosis is a major challenge as clinical signs are often non-specific and rare. A urinary sample should be analyzed in appropriate conditions before any antibiotic prescription. According to most guidelines, a bacterial threshold≥103CFU/ml associated with symptoms is acceptable to define UTI in patients with neurogenic bladder. The management of acute symptomatic UTI is not evidence-based. A management with a single agent and a short antibiotic treatment of 10 days or less seems effective. Antibiotic selection should be based on the patient's resistance patterns. Asymptomatic bacteriuria should not be treated to avoid the emergence of bacterial resistance. Regarding preventive measures, use of clean intermittent catheterization, intravesical botulinum toxin injection, and prevention using antibiotic cycling are effective. Bacterial interference is promising but randomized controlled trials are needed. Large ongoing cohorts and randomized controlled trials should soon provide more evidence-based data.

Evaluation of the ratio of the estimated area under the concentration-time curve to minimum inhibitory concentration (estimated AUIC) as a predictor of the outcome for tigecycline treatment for pneumonia due to multidrug-resistant bacteria in an intensive care unit

OBJECTIVES

Based on pharmacokinetics/pharmacodynamics (PK/PD) and the minimum inhibitory concentration (MIC) of tigecycline (TGC), dose increases have been advocated to maximize the efficacy against pneumonia that is suspected to be due to multidrug-resistant (MDR) bacteria in an intensive care unit. This practice-based study explored the relationship between the predicted PK parameter, the ratio of the area under the concentration-time curve to the 24 h of dosing/minimum inhibitory concentration (AUC_0-24/MIC or AUIC), and the clinical and microbiological outcomes in critically ill patients with pneumonia due to MDR bacteria.

METHODS

We conducted a prospective cohort study of the treatment of pneumonia due to MDR bacteria in an intensive care unit. The study patients were recruited and assigned to either TGC standard dose (SD, 50 mg q12 h) or high dose (HD, 100 mg q12 h) for the treatment of pneumonia due to MDR bacteria depending on the doctors' decisions. The relationships between the PK/PD parameters and outcomes were examined.

RESULTS

Over the study period, 105 patients were included in the study. Whereas C1/2, Cmin, MIC and AUC were dramatically higher in the HD group than in the SD group (all P < 0.05), the Cmax and AUIC had no difference in both groups (all P > 0.05). The patients in the HD group had a higher clinical cure rate than those in the SD group (P = 0.029), but the bacterial eradication rate and survival rate of the patients in the HD group were not better than those in SD group (P = 0.279 and 0.416, respectively). The Cmax, C1/2, Cmin and AUC in the cured group were higher than those in failure group (all P < 0.05). The MICs were dramatically higher in the failure group than those in cure group (P = 0.0001), which led to significantly lower AUICs (P = 0.0001). In the ROC analysis, the areas of Cmax, C1/2, Cmin, AUC, negative-MIC and AUIC under the ROC curve were 0.64, 0.69, 0.67, 0.66, 0.73 and 0.82, respectively. The sensitivity was ascertained to be 75% and the specificity was 89% when the AUIC cut-off value was considered to be 10.12. Moreover, the sensitivity was ascertained to be 63% and the specificity was 80% when the MIC cut-off value was considered to be 1.75 mg/L.

CONCLUSIONS

The AUIC and MIC are associated with tigecycline treatment outcomes in pneumonia due to MDR bacteria, and aiming to achieve an individualized AUIC ≥ 10.12 when MIC < 1.75 mg/L could improve outcomes.

IGBT-Based Pulsed Electric Fields Generator for Disinfection: Design and In Vitro Studies on Pseudomonas aeruginosa

Irreversible electroporation of cell membrane with pulsed electric fields is an emerging physical method for disinfection that aims to reduce the doses and volumes of used antibiotics for wound healing. Here we report on the design of the IGBT-based pulsed electric field generator that enabled eradication of multidrug resistant Pseudomonas aeruginosa PAO1 on the gel. Using a concentric electric configuration we determined that the lower threshold of the electric field required to kill P. aeruginosa PAO1 was 89.28 ± 12.89 V mm^-1, when 200 square pulses of 300 µs duration are delivered at 3 Hz. These parameters disinfected 38.14 ± 0.79 mm² area around the single needle electrode. This study provides a step towards the design of equipment required for multidrug-resistant bacteria disinfection in patients with pulsed electric fields.

A global priority list of the TOp TEn resistant Microorganisms (TOTEM) study at intensive care: a prioritization exercise based on multi-criteria decision analysis

The World Health Organization (WHO) proposed a global priority pathogen list (PPL) of multidrug-resistant (MDR) bacteria. Our current objective was to provide global expert ranking of the most serious MDR bacteria present at intensive care units (ICU) that have become a threat in clinical practice. A proposal addressing a PPL for ICU, arising from the WHO Global PPL, was developed. Based on the supporting data, the pathogens were grouped in three priority tiers: critical, high, and medium. A multi-criteria decision analysis (MCDA) was used to identify the priority tiers. After MCDA, mortality, treatability, and cost of therapy were of highest concern (scores of 19/20, 19/20, and 15/20, respectively) while dealing with PPL, followed by healthcare burden and resistance prevalence. Carbapenem-resistant (CR) Acinetobacter baumannii, carbapenemase-expressing Klebsiella pneumoniae (KPC), and MDR Pseudomonas aeruginosa were identified as critical organisms. High-risk organisms were represented by CR Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and extended-spectrum beta-lactamase (ESBL) Enterobacteriaceae. Finally, ESBL Serratia marcescens, vancomycin-resistant Enterococci, and TMP-SMX-resistant Stenotrophomonas maltophilia were identified as medium priority. We conclude that education, investigation, funding, and development of new antimicrobials for ICU organisms should focus on carbapenem-resistant Gram-negative organisms.

Effect of varying federal definitions on prevalence and characteristics associated with carbapenem-resistant Enterobacteriaceae in veterans with spinal cord injury

BACKGROUND

Patients with spinal cord injury (SCI) have a high risk for multidrug-resistant organisms, including carbapenem-resistant Enterobacteriaceae (CRE). Accurate and easily applied definitions are critical to identify CRE. This study describes CRE and associated characteristics in veterans with SCI per Centers for Disease Control and Prevention (CDC) and Department of Veterans Affairs (VA) definitions.

METHODS

A retrospective cohort of veterans with SCI and more than 1 culture with Escherichia coli, Klebsiella spp and/or Enterobacter spp between 2012 and 2013 was examined. Antibiotic susceptibility criteria of pre-2015 (CDC1) and post-2015 (CDC2) CDC definitions and pre-2017 (VA1) and post-2017 (VA2) VA definitions were used to identify CRE. CRE prevalence and characteristics are described for isolates meeting each definition, and agreement was assessed with the Cohen kappa.

RESULTS

We reviewed 21,514 isolates cultured from 6,974 veterans; 423 isolates met any CRE definition. Although agreement among definitions was high (kappa = 0.82-0.93), definitions including ertapenem resistance led to higher CRE prevalence (VA1 = 1.7% and CDC2 = 1.9% vs VA2 = 1.4% and CDC1 = 1.5%). Forty-four of 142 VA facilities had more than 1 CRE case defined by VA2; 10 facilities accounted for 60% of CRE cases. Almost all CRE was isolated from high-complexity, urban facilities, and the South had the highest proportion of CRE.

CONCLUSIONS

Varying federal definitions give different CRE frequencies in a high-risk population. Definitions including ertapenem resistance resulted in higher CRE prevalence but may overemphasize noncarbapenemase isolates. Thus, both federal definitions now highlight the importance of carbapenemase testing.

Colistin and polymyxin B for treatment of nosocomial infections in intensive care unit patients: pharmacoeconomic analysis

Background The emergence and rapid spread of multidrug-resistant gram-negative bacteria related to nosocomial infections is a growing worldwide problem, and polymyxins have become important due to the lack of new antibiotics. Objectives To evaluate the outcomes and pharmacoeconomic impact of using colistin and polymyxin B to treat nosocomial infections. Setting Neurosurgical, cardiovascular, or transplantation intensive care unit (ICU) at the Clinical Hospital of the University of Campinas (São Paulo, Brazil). Method A retrospective cohort study was conduct in patients in the ICU. The renal function was determined daily during treatment by measuring the serum creatinine. A cost minimization analysis was performed to compare the relative costs of treatment with colistin and polymyxin B. Main outcomes measure The outcomes were 30-day mortality and frequency and onset of nephrotoxicity after beginning treatment. Results Fifty-one patients treated with colistin and 51 with polymyxin B were included. 30-day mortality was observed in 25.49% and 33.33% of patients treated with colistin and polymyxin B, respectively; Nephrotoxicity was observed in 43.14% and 54.90% of patients in colistin and polymyxin B groups, respectively; and onset time of nephrotoxicity was 9.86 ± 13.22 days for colistin and 10.68 ± 9.93 days for polymyxin B group. Colistin treatment had a lower cost per patient compared to the cost for polymyxin B treatment (USD $13,389.37 vs. USD $13,639.16, respectively). Conclusion We found no difference between 30-day mortality and nephrotoxicity between groups; however, colistin proved to be the best option from a pharmacoeconomic point of view.

Terminalia bellirica fruit extracts: in-vitro antibacterial activity against selected multidrug-resistant bacteria, radical scavenging activity and cytotoxicity study on BHK-21 cells

Background

Identification of novel sources for developing new antibiotics is imperative with the emergence of antibiotic resistant bacteria. The fruits of Terminalia bellirica (Gaertn) Roxb., widely used in traditional medicine, were evaluated for antibacterial activity against multidrug-resistant (MDR) bacteria, antioxidant activity and cytotoxicity.

Methods

Twelve solvent extracts of T. bellirica fruits were prepared by direct aqueous extraction and sequential extraction with dichloromethane, methanol and water using Soxhlet, bottle-shaker and ultrasound sonicator methods. Antibacterial activity of the extracts was tested against 16 strains MDR bacteria—methicillin-resistant Staphylococcus aureus (MRSA), extended spectrum β-lactamase (ESBL) producing Escherichia coli and MDR Acinetobacter spp., Klebsiella pneumoniae and Pseudomonas aeruginosa—and 4 control organisms, using the cut-well diffusion method. The minimum inhibitory concentration (MIC) was determined using an agar dilution method. The radical scavenging activity of six antibacterial extracts was screened against 2,2′-diphenyl-2-picrylhydrazyl (DPPH) and correlation was established between EC₅₀ (50% effective concentration) values and the total phenolic content (TPC). Cytotoxicity was determined for the most potent antibacterial extract on baby hamster kidney (BHK-21) cells by Tryphan Blue exclusion method. Statistical analysis was carried out by one-way analysis of variance at significant level p < 0.05 using “SigmaPlot 10” and “R 3.2.0” software.

Results

All aqueous and methanol extracts displayed antibacterial activity (MIC 0.25–4 mg/mL) against all strains of MRSA, MDR Acinetobacter spp. and MDR P. aeruginosa. The sequential aqueous extracts (MIC, 4 mg/mL) inhibited ESBL producing-E. coli. None of the extracts exhibited activity against MDR K. pneumoniae (MIC > 5 mg/mL). The sequential methanol extract (Soxhlet) recorded high antibacterial activity and the highest DPPH radical scavenging activity (EC₅₀, 6.99 ± 0.15 ppm) and TPC content (188.71 ± 2.12 GAE mg/g).

The IC₅₀ (50% inhibition concentration) values of the most potent antibacterial extract—the direct aqueous extract from reflux method—on BHK-21 cells were 2.62 ± 0.06 and 1.45 ± 0.08 mg/ml with 24 and 48 h exposure, respectively.

Conclusions

Results indicate that T. bellirica fruit is a potential source for developing broad-spectrum antibacterial drugs against MDR bacteria, which are non-toxic to mammalian cells and impart health benefits by high antioxidant activity.

Marjoram extract down-regulates the expression of Pasteurella multocida adhesion, colonization and toxin genes: A potential mechanism for its antimicrobial activity

Due to the emergence of virulent and antibiotic-resistant microbes, natural antimicrobials from herbal origins have been given more attention as an alternative therapy. This study provides an in vitro research framework to investigate the antibacterial activities of 5 herbal (marjoram, garlic, onion, cinnamon and black seed) oil extracts against 16 multidrug-resistant (MDR) and virulent P. multocida serogroup A isolates recovered from dead and clinically diseased rabbits. Pathogenicity of the screened isolates was further proven experimentally and was verified by PCR analyses of 5 randomly selected virulence genes encoding attachment and colonization proteins (ptfA, pfhA, and omp87), sialidases (nanB) and dermonecrotoxin (toxA). A total of 12 P. multocida isolates were highly pathogenic with the possession of all examined virulence genes, while the other 4 isolates were of lower pathogenicity with expression of the target genes except toxA. In vitro anti-P. multocida activities of the 5 extracts and their synergism rates with 4 antibiotic drugs revealed that marjoram and cinnamon extracts had the highest antibacterial activities and the highest synergism rates against the screened isolates. Pasteurella multocida virulence gene expression profiles were assessed via real-time quantitative reverse transcription PCR (qRT-PCR) in response to marjoram extract. The quantitative analyses showed less than five-fold reduction in the targeted virulence genes expression in presence of marjoram extract compared with the control. The findings from this study document a novel molecular inhibitory activity of marjoram against P. multocida multiple virulence genes and provide a proof of concept for its implementation as an alternative candidate for the treatment of pasteurellosis in farm animals in future.

Potent effects of amino acid scanned antimicrobial peptide Feleucin-K3 analogs against both multidrug-resistant strains and biofilms of Pseudomonas aeruginosa

Pseudomonas aeruginosa is particularly difficult to treat because it possesses a variety of resistance mechanisms and because it often forms biofilms. Antimicrobial peptides represent promising candidates for future templates of antibiotic-resistant bacterial infections due to their unique mechanism of antimicrobial action. In this study, we first found that the antimicrobial peptide Feleucin-K3 has potent antimicrobial activity against not only the standard strain of P. aeruginosa but also against the multidrug-resistant strains isolated from clinics. Then, the structure-activity relationship of the peptide was investigated using alanine and D-amino acid scanning. Among the analogs synthesized, FK-1D showed much more potent antimicrobial activity, superior stability, and very low toxicity, and it was able to permeabilize bacterial membranes. Furthermore, it exhibited significant anti-biofilm activity. More importantly, FK-1D showed excellent antimicrobial activity in vivo, especially against clinical multidrug-resistant bacteria, in contrast to ceftazidime. Our results suggested that FK-1D could be subjected to fixed-point modification in the first and fourth sites to further optimize its medicinal properties and potential as a lead compound for the treatment of infections caused by multidrug-resistant P. aeruginosa and the associated biofilms.

Efficacy of sodium hypochlorite against multidrug-resistant Gram-negative bacteria

BACKGROUND

Increased antimicrobial resistance has been observed among many bacteria leading to treatment failures in human and veterinary medicine. Disinfection is a prerequisite for infection control and prevention in healthcare settings. Chlorine compounds are cost-effective and accessible worldwide.

AIM

To determine the efficacy of sodium hypochlorite (NaOCl) against multidrug-resistant Gram-negative bacteria (MDR-GNB).

METHODS

Minimum inhibitory concentrations (MICs) were determined using broth macro-dilution. Bactericidal efficacy was measured by qualitative and quantitative suspension tests followed by practical tests without mechanical action on stainless steel carriers. The guidelines of the German Association for Applied Hygiene were followed.

FINDINGS

Results varied remarkably depending on the method. MICs were 0.1% or 0.2% NaOCl. Qualitative suspension tests revealed up to 500-fold lower bactericidal concentrations. Pseudomonas aeruginosa (P = 0.0025) was significantly less susceptible in these tests whereas quantitative suspension tests revealed no significant differences between strains (P > 0.05). Practical tests determined bactericidal concentrations of 0.8-0.32% NaOCl at 1 min of contact and even lower concentrations for longer contact times. At 1 min, five Klebsiella were significantly less susceptible (P = 0.0124), whereas the lower susceptibility of P. aeruginosa was not confirmed. Organic load inhibited bactericidal activity significantly, whereas contact time had a marginal effect. Differing test results underline that MIC determination and qualitative suspension tests may be insufficient approaches to evaluate bacterial susceptibility or resistance.

CONCLUSION

NaOCl efficiently reduced Pseudomonas aeruginosa, Acinetobacter spp., and Klebsiella spp., most notably in the absence of organic matter. Strain- and species-specific differences in susceptibility were noticed, but in general MDR-GNB revealed no higher tolerance to NaOCl.

Extremely and pandrug-resistant bacteria extra-deaths: myth or reality?

In 2009, the European Centre for Disease Prevention and Control (ECDC) estimated that multidrug-resistant (MDR) bacterial infections were responsible for 25,000 extra-deaths per year. In 2015, another report estimated that 12,500 extra-deaths were attributable to MDR bacteria every year in France. Recently, the United Nations claimed that resistance to antimicrobials was a global scourge, forecasting 10 million deaths in 2050. Surprisingly, our antibiotic resistance surveillance system in Marseille, France, did not allowed us to observe similar trends. We herein compared our data on extremely drug-resistant (XDR)/pandrug-resistant (PDR) patient extra-deaths to evaluations and predictions from these reports. First, we retrospectively collect and analyze antibiotic resistance data produced by our settings between November 2009 and March 2015 to look for 30-day deaths attributable to XDR/PDR strains belonging to 11 bacterial species/genus. In parallel, we performed a PubMed literature search to look for articles published prior to July 2016 and describing human deaths due to PDR strains. Overall, 35,723 patients were infected by at least one bacterial species/genus of interest and 85 by XDR/PDR strains. Of these patients, only one death was attributable to a XDR bacterial infection in a patient with strong comorbidities and two consecutive septic shocks. Our literature review shows that only four articles described human deaths due to PDR bacteria. All together, these data allowed us to conclude that there is a large discrepancy between the real count of deaths attributable to XDR/PDR bacteria and alarmist predictions.

N-(1,3,4-oxadiazol-2-yl)benzamide analogs, bacteriostatic agents against methicillin- and vancomycin-resistant bacteria

Various reports of multidrug-resistant bacteria that are immune to all available FDA-approved drugs demand the development of novel chemical scaffolds as antibiotics. From screening a chemical library, we identified compounds with antibacterial activity. The most potent compounds, F6-5 and F6, inhibited growth of various drug-resistant Gram-positive bacterial pathogens at concentrations ranging from 1 μg/mL to 2 μg/mL. Both compounds were active against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate and vancomycin-resistant S. aureus (VISA and VRSA respectively) and vancomycin-resistant Enterococcus faecalis (VRE). Resistance generation experiments revealed that MRSA could develop resistance to the antibiotic ciprofloxacin but not to F6. Excitingly, F6 was found to be non-toxic against mammalian cells. In a mouse skin wound infection model, F6 was equipotent to the antibiotic fusidic acid in reducing MRSA burden.

Decontaminating surfaces with atomized disinfectants generated by a novel thickness-mode lithium niobate device

We evaluated the ability of a novel lithium niobate (LN) thickness-mode device to atomize disinfectants and reduce microbial burden on model surface materials. A small-scale plastic model housed the LN thickness-mode device and circular coupon surface materials including polycarbonate, polyethylene terephthalate, stainless steel, borosilicate glass, and natural rubber. Coupon surfaces were coated with methicillin-resistant Staphylococcus aureus (MRSA) or multidrug-resistant (MDR) strains of Gram-negative bacterial pathogens (Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii), atomized with disinfectant solutions of varying viscosity (including 10% bleach, 70% ethanol (EtOH), or 25% triethylene glycol (TEG)) using the LN thickness-mode device, and assessed for surviving bacteria. The LN thickness-mode device effectively atomized disinfectants ranging from low viscosity 10% bleach solution or 70% EtOH to highly viscous 25% TEG. Coupons harboring MDR bacteria and atomized with 10% bleach solution or 70% EtOH were effectively decontaminated with ~ 100% bacterial elimination. Atomized 25% TEG effectively eliminated 100% of K. pneumoniae (CRE) from contaminated coupon surfaces but not MRSA. The enclosed small-scale plastic model established proof-of-principle that the LN thickness-mode device could atomize disinfectants of varying viscosities and decontaminate coupon surface materials harboring MDR organisms. Future studies evaluating scaled devices for patient rooms are warranted to determine their utility in hospital environmental decontamination.

Decolonization of Intestinal Carriage of MDR/XDR Gram-Negative Bacteria with Oral Colistin in Patients with Hematological Malignancies: Results of a Randomized Controlled Trial

Background

Intestinal colonization by MDR/XDR gram-negative bacteria leads to an increased risk of subsequent bloodstream infections (BSI) in patients receiving chemotherapy as a treatment for hematologic malignancies.

Objectives

The objective of this study was to evaluate the efficacy of oral colistin in eradicating the intestinal carriage of MDR/XDR Gram-negative bacteria in patients with hematological malignancies.

Methods

In a tertiary hematology center, adult patients with intestinal colonization by MDR/XDR Gram-negative bacteria were included in a randomized controlled trial (RCT) during a period from November 2016 to October 2017. Patients were treated with oral colistin for 14 days or observed with the primary outcome set as decolonization on day 21 post-treatment. Secondary outcomes included treatment safety and changes in MICs of isolated microorganisms. ClinicalTrials.gov Identifier: NCT02966457.

Results

Short-time positive effect (61.3% vs 32.3%; OR 3.32; 95% CI 1.17-9.44; p=0.0241) was demonstrated on the day 14 of colistin treatment, without any statistical difference on day 21 post-treatment. The incidence of BSI in decolonization group was lower in the first 30 days after the intervention (3.2% vs. 12.9%), but overall in the 90-day observation period, it did not show any advantages comparing to control group (log-rank test; p=0.4721). No serious adverse effects or increase in resistance to colistin was observed.

Conclusions

This study suggests that in hematological patients the strategy of selective intestinal decolonization by colistin may be beneficial to decrease the rate of MDR/XDR Gram-negative intestinal colonization and the risk of BSI in the short-term period, having no long-term sustainable effects.

Potential Alternative Treatment of Ocular Bacterial Infections by Oil Derived from Syzygium aromaticum Flower (Clove)

Purpose/Aim: This study aims to evaluate the predisposing risk factors and antibiotic resistance of bacterial corneal ulcer to commonly used antibiotics. In addition, assess the in vitro efficacy of plant-derived essential oils (EOs) as safe and effective antimicrobial agents.

METHODS

Demographic features and predisposing risk factors of corneal ulcer patients were recorded. Isolation and identification of bacteria was performed using conventional microbiological methods. Antibacterial activity was determined by disk diffusion and the micro-dilution broth methods. EOs were extracted by steam distillation and were analyzed by gas chromatography mass spectrometry technique.

RESULTS

Out of the 200 patients with corneal ulcer evaluated in this study, the main predisposing factor of bacterial corneal ulcer was trauma (26.5%) and 96.7% isolates were multidrug resistant. Staphylococcus aureus was the predominant isolate 33 cases. Antibiotic susceptibility of bacterial isolates showed that the fourth-generation fluoroquinolones, gatifloxacin was the most effective antibiotic with sensitivity rate 81.3%. Seven selected EOs showed significant activity against most of the tested bacteria. Syzygium aromaticum oil showed high activity against all tested bacterial species with highest sensitivity rate (97.5%) and low minimal inhibitory concentration values against S. aureus (0.10 µl/ml). The chemical composition of the EOs showed that the monoterpenes were predominant. The main constituent of S. aromaticum oil was eugenol (76%).

CONCLUSIONS

The current study showed that S. aromaticum oil had high antibacterial activity that could be helpful in the treatment of ocular bacterial infections to minimizing the possible side effects of commonly used antibiotic.

Inhaled Antibiotics for Ventilator-Associated Infections

Multidrug-resistant organisms are creating a challenge for physicians treating the critically ill. As new antibiotics lag behind the emergence of worsening resistance, intensivists in countries with high rates of extensively drug-resistant bacteria are turning to inhaled antibiotics as adjunctive therapy. These drugs can provide high concentrations of drug in the lung that could not be achieved with intravenous antibiotics without significant systemic toxicity. This article summarizes current evidence describing the use of inhaled antibiotics for the treatment of bacterial ventilator-associated pneumonia and ventilator-associated tracheobronchitis. Preliminary data suggest aerosolized antimicrobials may effectively treat resistant pathogens with high minimum inhibitory concentrations.

pH-triggered charge-reversible of glycol chitosan conjugated carboxyl graphene for enhancing photothermal ablation of focal infection

Subcutaneous abscesses infected by multidrug-resistant bacteria are becoming an increasing challenge to human health. To address this challenge, a surface-adaptive and biocompatible glycol chitosan conjugated carboxyl graphene (GCS-CG) is developed, which exhibits unique self-adaptive target to the acidic microenvironment of abscess (∼pH 6.3) and no damage to the healthy tissue (pH 7.4) around the abscess. Originally, following conjugated with GCS, the absorbance of CG obviously increases in the near-infrared (NIR) region, enabling GCS-CG to generate an increment amount of heat. GCS-CG shows fast pH-responsive surface charge transition from negative to positive, which presents strong adherence to negatively charged bacteria surface in abscess, while exhibits poor affinity to host cells in healthy tissues. The local temperature of NIR-irradiated GCS-CG is estimated to be higher than their ambient temperature, ensuring targeted heating and eradicating the bacteria to reduce the damage to tissue; hence, wound healing is accelerated. Moreover, the in vitro and in vivo biosafety results demonstrate that GCS-CG presents greatly biocompatible even at a high concentration of 1 mg·mL^-1. Given the above advantages as well as the simple preparation, graphene developed here may provide a new potential application as a useful antibacterial agent in the areas of healthcare.

STATEMENT OF SIGNIFICANCE

A surface-adaptive nanomaterial, glycol chitosan conjugated carboxyl graphene (GCS-CG) is developed, which realizes the acidity-triggered bacteria targeting. GCS-CG can result in direct thermal ablation of bacteria and enhancement of the infected wound healing, but exhibit no damage to healthy tissues. The pH-responsive GCS-CG described here, containing no antibiotics, has great potentials in treating bacterial infection and even multidrug-resistant bacteria.

Low incidence of multidrug-resistant bacteria and nosocomial infection due to a preventive multimodal nosocomial infection control: a 10-year single centre prospective cohort study in neurocritical care

Background

Nosocomial infection (NI) control is an important issue in neurocritical care due to secondary brain damage and the increased morbidity and mortality of primary acute neurocritical care patients. The primary aim of this study was to determine incidence of nosocomial infections and multidrug-resistant bacteria and seek predictors of nosocomial infections in a preventive multimodal nosocomial infection protocol in the neurointensive care unit (NICU). The secondary aim focused on their impact on stay, mortality and cost in the NICU.

Methods

A10-year, single-centre prospective observational cohort study was conducted on 3464 acute brain disease patients. There were 198 (5.7%) patients with nosocomial infection (wound 2.1%, respiratory 1.8%, urinary 1.0%, bloodstream 0.7% and other 0.1%); 67 (1.9%) with Extended spectrum beta-lactamase (ESBL); 52 (1.5%) with Methicillin-resistant Staphylococcus aureus (MRSA), nobody with Vancomycin-resistant enterococcus (VRE). The protocol included hygienic, epidemiological status and antibiotic policy. Univariate and multivarite logistic regression analysis was used for identifying predictors of nosocomial infection.

Results

From 198 NI patients, 153 had onset of NI during their NICU stay (4.4%; wound 1.0%, respiratory 1.7%, urinary 0.9%, bloodstream 0.6%, other 0.1%); ESBL in 31 (0.9%) patients, MRSA in 30 (0.9%) patients. Antibiotics in prophylaxis was given to 63.0% patients (59.2 % for operations), in therapy to 9.7% patients. Predictors of NI in multivariate logistic regression analysis were airways (OR 2.69, 95% CI 1.81-3.99, p<0.001), urine catheters (OR 2.77, 95% CI 1.00-7.70, p=0.050), NICU stay (OR 1.14, 95% CI 1.12-1.16, p<0.001), transfusions (OR 1.79, 95% CI 1.07-2.97, p=0.025) antibiotic prophylaxis (OR 0.50, 95% CI 0.34-0.74, p<0.001), wound complications (OR 2.30, 95% CI 1.33-3.97, p=0.003). NI patients had longer stay (p<0.001), higher mortality (p<0.001) and higher TISS sums (p<0.001) in the NICU.

Conclusions

The presented preventive multimodal nosocomial infection control management was efficient; it gave low rates of nosocomial infections (4.2%) and multidrug-resistant bacteria (ESBL 0.9%, MRSA 0.9% and no VRE). Strong predictors for onset of nosocomial infection were accesses such as airways and urine catheters, NICU stay, antibiotic prophylaxis, wound complications and transfusion. This study confirmed nosocomial infection is associated with worse outcome, higher cost and longer NICU stay.

Short-course antibiotic therapy for critically ill patients treated for postoperative intra-abdominal infection: the DURAPOP randomised clinical trial

PURPOSE

Shortening the duration of antibiotic therapy (ABT) is a key measure in antimicrobial stewardship. The optimal duration of ABT for treatment of postoperative intra-abdominal infections (PIAI) in critically ill patients is unknown.

METHODS

A multicentre prospective randomised trial conducted in 21 French intensive care units (ICU) between May 2011 and February 2015 compared the efficacy and safety of 8-day versus 15-day antibiotic therapy in critically ill patients with PIAI. Among 410 eligible patients (adequate source control and ABT on day 0), 249 patients were randomly assigned on day 8 to either stop ABT immediately (n = 126) or to continue ABT until day 15 (n = 123). The primary endpoint was the number of antibiotic-free days between randomisation (day 8) and day 28. Secondary outcomes were death, ICU and hospital length of stay, emergence of multidrug-resistant (MDR) bacteria and reoperation rate, with 45-day follow-up.

RESULTS

Patients treated for 8 days had a higher median number of antibiotic-free days than those treated for 15 days (15 [6-20] vs 12 [6-13] days, respectively; P < 0.0001) (Wilcoxon rank difference 4.99 days [95% CI 2.99-6.00; P < 0.0001). Equivalence was established in terms of 45-day mortality (rate difference 0.038, 95% CI - 0.013 to 0.061). Treatments did not differ in terms of ICU and hospital length of stay, emergence of MDR bacteria or reoperation rate, while subsequent drainages between day 8 and day 45 were observed following short-course ABT (P = 0.041).

CONCLUSION

Short-course antibiotic therapy in critically ill ICU patients with PIAI reduces antibiotic exposure. Continuation of treatment until day 15 is not associated with any clinical benefit. CLINICALTRIALS.

GOV IDENTIFIER

NCT01311765.

Higher third-generation cephalosporin prescription proportion is associated with lower probability of reducing carbapenem use: a nationwide retrospective study

Background

The ongoing extended spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) pandemic has led to an increasing carbapenem use, requiring release of guidelines for carbapenem usage in France in late 2010. We sought to determine factors associated with changes in carbapenem use in intensive care units (ICUs), medical and surgical wards between 2009 and 2013.

Methods

This ward-level multicentre retrospective study was based on data from French antibiotic and multidrug-resistant bacteria surveillance networks in healthcare facilities. Antibiotic use was expressed in defined daily doses per 1000 patient-days. Factors associated with the reduction in carbapenem use (yes/no) over the study period were determined from random-effects logistic regression model (493 wards nested within 259 healthcare facilities): ward characteristics (type, size…), ward antibiotic use (initial antibiotic use [i.e., consumption of a given antibiotic in 2009], initial antibiotic prescribing profile [i.e., proportion of a given antibiotic in the overall antibiotic consumption in 2009] and reduction in the use of a given antibiotic between 2009 and 2013) and regional ESBL-PE incidence rate in acute care settings in 2011.

Results

Over the study period, carbapenem consumption in ICUs (n = 85), medical (n = 227) and surgical wards (n = 181) was equal to 73.4, 6.2 and 5.4 defined daily doses per 1000 patient-days, respectively. Release of guidelines was followed by a significant decrease in carbapenem use within ICUs and medical wards, and a slowdown in use within surgical wards. The following factors were independently associated with a higher probability of reducing carbapenem use: location in Eastern France, higher initial carbapenem prescribing profile and reductions in consumption of fluoroquinolones, glycopeptides and piperacillin/tazobactam. In parallel, factors independently associated with a lower probability of reducing carbapenem use were ICUs, ward size increase, wards of cancer centres, higher initial third-generation cephalosporin (3GC) prescribing profile and location in high-risk regions for ESBL-PE.

Conclusions

Our study suggests that a decrease in 3GCs in the overall antibiotic use and the continuation of reduction in fluoroquinolone use, could allow reducing carbapenem use, given the well-demonstrated role of 3GCs and fluoroquinolones in the occurrence of ESBL-PE. Thus, antibiotic stewardship programs should target wards with higher 3GC prescription proportions to reduce them.