Carbapenem use in critically ill patients

Carbapenem-resistant Acinetobacter baumannii raises global alarm for new antibiotic regimens

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a top-priority pathogen causing a nosocomial infection that increases morbidity and mortality. Treatment options for CRAB are relatively limited by pharmacokinetic restrictions, such as substantial toxicity. Therefore, we must better understand this pathogen to develop new treatments and control strategies. The review aims to provide an overview of the current understanding of acquired, adaptive, and intrinsic Carbapenem-resistant pathways in A. baumannii, as well as its consequences on healthcare systems, particularly critical care units. The review also provides insights into how CRAB infections are currently managed worldwide and why novel therapeutic regimens are needed. The peculiarity of A. baumannii and its often reported virulence factors have been discussed further. In conclusion, the purpose of this review is to emphasize the current knowledge on CRAB, as it causes major worry in the field of nosocomial infections as well as overall public health.

Whole genome sequencing characterization and comparative genome analysis of Acinetobacter baumannii JJAB01: A comprehensive insights on antimicrobial resistance and virulence genotype

The emergence of antibiotic resistance has significantly elevated the threat posed by Acinetobacter baumannii as an opportunistic pathogen. A.baumannii, a notorious bacterium, poses a serious threat to health care, leading to severe nosocomial infections, particularly in immunocompromised individuals. Whole-Genome Sequencing studies are efficient in providing accurate genetic information, aiding in detecting outbreaks, surveillance of resistance, and controlling infection transmission. In this study, we investigated the whole genome of a clinical isolate A. baumannii JJAB01 which sourced from a urine sample of an Intensive Care Unit (ICU) patient. This strain showed resistance to 24 available antibiotics, signifying Extremely Drug Resistant (XDR) and high potential for pathogenicity. Whole Genome Sequencing was performed using Illumina, and the raw reads were evaluated using the FastQC tool. Genome assembly and annotation were performed with Unicycler and the RAST server. The JJAB01 genome is 4.07 Mb with a GC content of 38.9 %. A total of 51 and 31 virulence factors and antimicrobial-resistant (AMR) genes were predicted using the VFDB and CARD databases. Comparative genome studies were carried out on virulence factors, resistance genes, prophages, and Multi-Locus Sequence Typing (MLST) across twelve closely related A. baumannii genomes, including JJAB01, X4-584, X4-705, 2023CK-00423, 2023CK-00890, 2023CK-00127, 2022CK-00066, B20AB01, B20AB10, F20AB03, G20AB08, and X4-65. These computational investigations in this study emphasis the multidimensional nature of the ICU strain JJAB01 and its genetic similarity to other strains, thereby enhancing our understanding of drug resistance and the pathogenicity associated with A. baumannii infections.

Molecular Identification of OXA Carbapenemase-Encoding Genes in Acinetobacter baumannii Isolated from Patients in Critical Care in Egypt

Background: The emergence of carbapenem-resistant Acinetobacter baumannii (CRAB) in hospitals, particularly within critical care units, has garnered substantial global concern. CRAB commonly arises from the degradation by various ß-lactamases. Objective: We aimed to assess OXA-type carbapenemases in clinical isolates of A. baumannii obtained from an Egyptian tertiary care facility. Patients and Methods: This study examined 25 distinct A. baumannii strains collected from various clinical samples of patients in intensive care unit. Bacterial identification was conducted utilizing both traditional methods and the Vitek2 system. Antibiotic resistance profiles were assessed according to the European Committee on Antimicrobial Susceptibility Testing standards using the Vitek2 Compact automated system. Additionally, multiplex real-time polymerase chain reaction was used to identify the presence of blaOXA23, blaOXA24, blaOXA51, and blaOXA58 carbapenemase genes. Colistin susceptibility was assessed utilizing the broth microdilution method. Results: Carbapenem resistance was identified in 100% of the studied isolates. The blaOXA51 gene was detected in all A. baumannii strains. The gene blaOXA23 was identified in 22 strains (88%), whereas blaOXA24 and blaOXA58 were present in 15 strains (60%). All isolates, except one, co-harbored two or more OXA encoding genes. Colistin resistance was detected in 4 of 25 strains (16%). Conclusion: Our findings demonstrate the widespread distribution of CRAB isolates that co-harbor multiple carbapenemase-encoding genes. Molecular epidemiological studies and the surveillance of antibiotic resistance profiles may aid in identifying and tracing the origins of resistant bacteria, thereby limiting their spread.

The effects of single and multiple resistance mechanisms on bacterial response to meropenem

OBJECTIVES

Meropenem is commonly used against Pseudomonas aeruginosa. Traditionally, the time unbound antibiotic concentration exceeds the MIC (fT>MIC) is used to select carbapenem regimens. We aimed to characterize the effects of different baseline resistance mechanisms on bacterial killing and resistance emergence; evaluate whether fT>MIC can predict these effects; and, develop a novel Quantitative and Systems Pharmacology (QSP) model to describe the effects of baseline resistance mechanisms on the time-course of bacterial response.

METHODS

Seven isogenic P. aeruginosa strains with a range of resistance mechanisms and MICs were used in 10-day hollow-fiber infection model studies. Meropenem pharmacokinetic profiles were simulated for various regimens (t1/2,meropenem = 1.5 h). All viable counts on drug-free, 3 × MIC, and 5 × MIC meropenem-containing agar across all strains, five regimens, and control (n = 90 profiles) were simultaneously subjected to QSP modeling. Whole genome sequencing was completed for total population samples and emergent resistant colonies at 239 h.

RESULTS

Regimens achieving ≥98%fT>1×MIC suppressed resistance emergence of the mexR knockout strain. Even 100%fT>5 × MIC failed to achieve this against the strain with OprD loss and the ampD and mexR double-knockout strain. Baseline resistance mechanisms affected bacterial outcomes, even for strains with the same MIC. Genomic analysis revealed that pre-existing resistant subpopulations drove resistance emergence. During meropenem exposure, mutations in mexR were selected in strains with baseline oprD mutations, and vice versa, confirming these as major mechanisms of resistance emergence. Secondary mutations occurred in lysS or argS, coding for lysyl and arginyl tRNA synthetases, respectively.

DISCUSSION

The QSP model well-characterized all bacterial outcomes of the seven strains simultaneously, which fT>MIC could not.

Precision Dosing of Meropenem in Adults with Normal Renal Function: Insights from a Population Pharmacokinetic and Monte Carlo Simulation Study

This study aimed to develop a population pharmacokinetic (PK) model for meropenem in healthy adults and explore optimal dosing regimens for patients with normal renal function. PK samples were obtained from 12 healthy participants, which were analyzed using noncompartmental analysis and nonlinear mixed-effect modeling. The PK profiles of meropenem were characterized using a two-compartment model, and serum creatinine level was identified as a significant covariate affecting total clearance. Monte Carlo simulations were conducted using this model to inform dosing recommendations. The target index for meropenem efficacy was defined as the cumulative percentage over 24 h during which free (f) drug concentration exceeded the minimum inhibitory concentration (MIC) under steady state conditions (fT>MIC). These simulations indicated that the current dosage regimen of 1 g for 30 min infusions every 8 h achieved a 90% probability of target attainment (PTA) for 40%fT>MIC when the MIC was <2 mg/L. However, to achieve more stringent therapeutic targets, such as a 90%PTA for 100%fT>MIC or a 90%PTA for 100%fT>4MIC, higher doses administered as 3 h extended infusions or as continuous infusions may be necessary. These results highlight the need for model-informed precision dosing to enhance the efficacy of meropenem therapy across various MIC levels and therapeutic targets.

Metabolomics Method in Understanding and Sensitizing Carbapenem-Resistant Acinetobacter baumannii to Meropenem

Carbapenem-resistant Acinetobacter baumannii (CRAB) strains are prevalent worldwide and represent a major threat to public health. However, treatment options for infections caused by CRAB are very limited as they are resistant to most of the commonly used antibiotics. Consequently, understanding the mechanisms underlying carbapenem resistance and restoring bacterial susceptibility to carbapenems hold immense importance. The present study used gas chromatography-mass spectrometry (GC-MS)-based metabolomics to investigate the metabolic mechanisms of antibiotic resistance in clinically isolated CRAB. Inactivation of the pyruvate cycle and purine metabolism is the most typical characteristic of CRAB. The CRAB exhibited a reduction in the activity of enzymes involved in the pyruvate cycle, proton motive force, and ATP levels. This decline in central carbon metabolism resulted in a decrease in the metabolic flux of the α-ketoglutarate-glutamate-glutamine pathway toward purine metabolism, ultimately leading to a decline in adenine nucleotide interconversion. Exogenous adenosine monophosphate (AMP) and adenosine triphosphate (ATP) enhance the killing efficacy of Meropenem against CRAB. The combination of ATP and Meropenem also has a synergistic effect on eliminating CRAB persisters and the biofilm, as well as protecting mice against peritonitis-sepsis. This study presents a novel therapeutic modality to treat infections caused by CRAB based on the metabolism reprogramming strategy.

Carbapenem-Resistant Acinetobacter baumannii Bloodstream Infection in a Ghanaian Patient with Unilateral Diaphragmatic Eventration and HIV Type 1 Infection

Carbapenem-resistant Acinetobacter baumannii infection is a critically prioritized pathogen by the World Health Organization and a cause for growing concern due to increased mortality among hospitalised patients. Phrenic nerve palsy is a rare complication of herpes zoster infection of the C3, C4, and C5 nerve roots. We present a case of bloodstream carbapenem-resistant A. baumannii infection in a Ghanaian patient with HIV type 1 infection and multiple risk factors, including unilateral diaphragmatic eventration with compression atelectasis likely secondary to phrenic nerve palsy due to herpes zoster infection, consequently leading to recurrent hospital and ICU admission. In this case, we emphasize the need for clinicians in LMICs to be aware of CRAB, in order to advocate for the availability of evidence-based medicines in resource-limited settings for appropriate treatment. In addition, we illustrate the importance of a high index of suspicion for infection with carbapenem-resistant organisms such as A. baumannii and highlight a rare and severe complication of herpes zoster infection in the form of phrenic nerve palsy and consequent diaphragmatic eventration.

Method Development for Determination of Doripenem in Human Plasma via Capillary Electrophoresis Coupled with Field-Enhanced Sample Stacking and Sweeping

In this study, we established a novel capillary electrophoresis method for monitoring the concentration of doripenem in human plasma. As a time-dependent antibiotic, doripenem maximizes its antibacterial effects and minimizes the potential for antibiotic resistance through careful therapeutic drug monitoring. Two online preconcentration techniques, field-enhanced sample stacking (FESS) and sweeping, were coupled to enhance the detection sensitivity. Briefly, an uncoated fused silica capillary (40 cm × 50 μm i.d) was rinsed with a high conductivity buffer (HCB) composed of 150 mM phosphate buffer (NaH2PO4, pH 2.5) and 20% methanol. A large sample plug prepared in a low-conductivity phosphate buffer (50 mM NaH2PO4, pH 2.5) was then hydrodynamically injected (5 psi, 80 s) into the capillary. Under an applied voltage of -30 kV, the analyte was accumulated at the FESS boundary and swept by the negatively charged micelles toward the UV detector. Plasma samples were pretreated by solid-phase extraction (SPE) to eliminate endogenous interferences. The validation results demonstrated a high coefficient of determination (r2 > 0.9995) for the regression curve with impressive precision and accuracy: relative standard deviation (RSD) <5.86% and relative error <4.63%. The limit of detection (LOD, S/N = 3) for doripenem was determined to be 0.4 μg/mL. Compared to the conventional micellar electrokinetic chromatography method, our developed method achieved a sensitivity enhancement of up to 488-fold for doripenem. Furthermore, the newly developed method successfully quantified doripenem concentrations in plasma samples obtained from patients accepting doripenem regimens, proving its application potential in the clinical realm.

Burden of Carbapenem Resistant Acinetobacter baumannii Harboring blaOXA Genes in the Indian Intensive Care Unit

Objectives:

The World Health Organization (WHO) mentioned Acinetobacter baumannii as a “priority of concern” in 2017. Acinetobacter baumannii generally infects immunocompromised patients and causes various nosocomial infections in the intensive care unit (ICU) such as bacteremia, meningitis, ventilator-associated pneumonia, other respiratory infections, and surgical site infections. As oxacillinase has weak hydrolysis activity, more work was needed on this class-D beta-lactamase. Hence, the current Systematic review focuses on the A. baumannii’s oxacillinase (Class-D beta-lactamases) enzyme and its variants collected during 2013–2020 in India for complete genome sequencing.

Method:

This Systematic review has been done according to PRISMA guideline 2020. We have used the Bacterial and Viral Bioinformatic Resource Centre (bv-brc.org) system for comparative genome analysis. The protein Basic Local Alignment Search Tool (BLAST) was used to identify similarities between sequences, in which BLOSUM62 was used as a scoring matrix. Clustal-W was used for multiple sequence alignment. A phylogenetic tree of the blaOXA gene family has been constructed using MEGA version 11.

Result:

In India during 2013–2020, for genome sequencing of A. baumannii, the highest number of samples was collected from blood (36%), following the ETA (30%). The average G+C % content was 38.95%. Among the 339 A. baumannii isolates, a maximum of 189 (55.75%) strains caused pneumonia, whereas 113 (33.33%) strains were involved in bacteremia. Carbapenems seemed effective, but resistance against them was higher. Among all A. baumannii genomes, bla-OXA-23 had the highest frequency (314; 92.62%), followed by bla-OXA-66 (241; 71.09%) in India.

Conclusion:

Our findings indicated that a high percentage of A. baumannii strains that produce oxacillinases exist in India, emphasizing the necessity for indigenous molecular surveillance to assist effective management and preventative initiatives. Comparative genomics and next-generation sequencing will offer tremendous potential for tracking and regulating the spread of this dangerous bacterium.

Evaluation and Analysis of the Rationality of Clinical Use of Carbapenems in Surgical Departments of a Tertiary Hospital in Southwest China

Purpose

With the increasing frequency and intensity of carbapenem consumption, carbapenem-resistant organisms (CRO) have become a focus of anti-infection research. This study aimed to evaluate the rationality of the clinical use of carbapenems among inpatients in the surgical departments of a tertiary hospital in southwest China.

Patients and methods

A point-score system was established for evaluation based on the clinical practices in surgical departments and selected carbapenem prescriptions from June 2020 to June 2021 for hepatobiliary surgery, gastrointestinal surgery, and neurosurgery in the study hospital. Prescriptions with a total score ≥ 270 were defined as rational. Descriptive statistics were used to describe the characteristics and rationality of the prescriptions. The chi-square test, Mann-Whitney U-test, and Kruskal-Wallis H-test were used to compare characteristics between rational and irrational prescriptions. Linear regression analysis was used to determine the factors affecting the rationality of carbapenem prescriptions.

Results

According to 192 carbapenem prescription records, the median age of patients was 62 years [IQR, 48.0-73.0], and 20% of patients had abdominal infections, 10% had lung infections, 14% had intracranial infections, and 3% had urinary tract infections. 56% of carbapenem prescriptions were irrational. Compared with rational carbapenem prescriptions, irrational prescriptions had a higher proportion of those with inappropriate indications (49% vs 0%, p < 0.05), incorrect variety selection (15% vs 0%, p<0.05), and unreasonable assessment of etiology and efficacy (46% vs 8%, p < 0.05). Linear regression analysis suggested that the diagnosis of cholecystitis (standardized regression coefficient=0.183, p<0.05) and replaced medication (standardized regression coefficient = 0.154, p<0.05) influenced the rationality of carbapenem prescriptions.

Conclusion

Our study shows that the irrational use of carbapenems deserves attention, especially in surgical departments. Interventions for carbapenem use that are based on evaluation criteria should be developed to reduce the emergence and spread of carbapenem-resistant bacteria.

Plethora of Antibiotics Usage and Evaluation of Carbapenem Prescribing Pattern in Intensive Care Units: A Single-Center Experience of Malaysian Academic Hospital

Excessive antibiotic consumption is still common among critically ill patients admitted to intensive care units (ICU), especially during the coronavirus disease 2019 (COVID-19) period. Moreover, information regarding antimicrobial consumption among ICUs in South-East Asia remains scarce and limited. This study aims to determine antibiotics utilization in ICUs by measuring antibiotics consumption over the past six years (2016−2021) and specifically evaluating carbapenems prescribed in a COVID-19 ICU and a general intensive care unit (GICU) during the second year of the COVID-19 pandemic. (2) Methods: This is a retrospective cross-sectional observational analysis of antibiotics consumption and carbapenems prescriptions. Antibiotic utilization data were estimated using the WHO Defined Daily Doses (DDD). Carbapenems prescription information was extracted from the audits conducted by ward pharmacists. Patients who were prescribed carbapenems during their admission to COVID-19 ICU and GICU were included. Patients who passed away before being reviewed by the pharmacists were excluded. (3) Results: In general, antibiotics consumption increased markedly in the year 2021 when compared to previous years. Majority of carbapenems were prescribed empirically (86.8%). Comparing COVID-19 ICU and GICU, the reasons for empirical carbapenems therapy in COVID-19 ICU was predominantly for therapy escalation (64.7% COVID-19 ICU vs. 34% GICU, p < 0.001), whereas empirical prescription in GICU was for coverage of extended-spectrum beta-lactamases (ESBL) gram-negative bacteria (GNB) (45.3% GICU vs. 22.4% COVID-19 ICU, p = 0.005). Despite microbiological evidence, the empirical carbapenems were continued for a median (interquartile range (IQR)) of seven (5−8) days. This implies the need for a rapid diagnostic assay on direct specimens, together with comprehensive antimicrobial stewardship (AMS) discourse with intensivists to address this issue.

Whole Genome Sequence Analysis of Multidrug Resistant Escherichia coli and Klebsiella pneumoniae Strains in Kuwait

The spread of carbapenem-resistant Escherichia coli and Klebsiella pneumoniae is a global concern. The management of infections caused by multidrug resistance (MDR) isolates poses substantial clinical challenges in both hospitals and communities. This study aimed to investigate the genetic characteristics and variations of MDR E. coli and K. pneumoniae isolates. Bacterial identification and antibiotic susceptibility testing against 19 antibiotics were performed by standard methods. Whole genome sequencing (WGS) was carried out on eight carbapenem-resistant isolates using an Illumina MiSeq platform. The assembled draft genomes were annotated, then sequences were blasted against antimicrobial resistance (AMR) genes database. WGS detected several resistance genes mediating the production of β-lactamases, including carbapenems and extended-spectrum β-lactamase genes as (bla_OXA-1/-48, bla_KPC-2/-29, bla_CMY-4/-6, bla_SHV-11/-12, bla_TEM-1, bla_CTX-M-15, bla_OKP-B, bla_ACT and bla_EC). Furthermore quinolone resistance including oqxA/oqxB, aac(6′)-Ib-cr5, gyrA_D87N, gyrA_S83F, gyrA_S83L, parC_S80I, parE_S458A, parE_I355T, parC_S80I, and qnrB1. In addition to aminoglycoside modifying enzymes genes (aph(6)-Id, aph(3″)-Ib, aac(3)-IIa, aac(6′)-Ib, aadA1, aadA2 and aadA5), trimethoprim-sulfamethoxazole (dfrA12/A14/A17 and sul1/sul2), tetracycline (tetA and tetB), fosfomycin (fosA and uhpT_E350Q) resistance genes, while other genes were detected conferring chloramphenicol (floR, catA2, and efflux pump cmIA5), macrolides resistance (mph(A) and erm(B), and quaternary ammonium efflux pump qacEdelta. Bleomycin and colistin resistance genes were detected as ble and pmrB_R256G, respectively. Comprehensive analysis of MDR strains provided by WGS detected variable antimicrobial resistance genes and their precise resistance mechanism. WGS is essential for control and prevention strategies to combat the growing threat of AMR and the implementation of multifaceted interventions are needed.

Evaluation of Empirical Meropenem Bolus Protocol in Pseudomonas aeruginosa: A Three-Year Analysis in Tertiary Intensive Care Unit

Purpose

To describe meropenem empirical use, susceptibility trend, and associated factors for acquired nonsusceptibility in P. aeruginosa in the intensive care unit.

Patients and Methods

This study was conducted in the intensive and high care unit of a tertiary care hospital in Indonesia to evaluate empirical meropenem bolus administration protocol. All patients admitted during the 3 year study period from January 2018 through January 2021 with culture-confirmed P. aeruginosa infection were included in the study. Primary data were collected from hospital database electronic medical record and series of local biannual report of microorganism susceptibility pattern.

Results

The data suggested that there was increasing trend in meropenem nonsusceptibility and multidrug-resistance rates. A total of 135 patients with various primary diagnoses and comorbidities were studied. P. aeruginosa isolates were mostly (73.4%) obtained from sputum specimen. Empirical meropenem therapy was administrated in 24.4% of patients with standard- and high-dose as indicated. Nonsusceptibility was acquired in 37% patients who mostly received empirical therapy. Multivariable analysis revealed protocol being evaluated as a statistically significant risk factor for nonsusceptibility in P. aeruginosa (PR = 30.65; p <0.001).

Conclusion

Empirical meropenem administration protocol in this study was an independent determinant of nonsusceptibility acquisition in P. aeruginosa. These findings proved that empirical therapeutic strategy modification is indispensable and routine evaluation practice should be promulgated.

Virulence Potential and Treatment Options of Multidrug-Resistant (MDR) Acinetobacter baumannii

Acinetobacter baumannii is an opportunistic pathogen which is undoubtedly known for a high rate of morbidity and mortality in hospital-acquired infections. A. baumannii causes life-threatening infections, including; ventilator-associated pneumonia (VAP), meningitis, bacteremia, and wound and urinary tract infections (UTI). In 2017, the World Health Organization listed A. baumannii as a priority-1 pathogen. The prevalence of A. baumannii infections and outbreaks emphasizes the direct need for the use of effective therapeutic agents for treating such infections. Available antimicrobials, such as; carbapenems, tigecycline, and colistins have insufficient effectiveness due to the appearance of multidrug-resistant strains, accentuating the need for alternative and novel therapeutic remedies. To understand and overcome this menace, the knowledge of recent discoveries on the virulence factors of A. baumannii is needed. Herein, we summarized the role of various virulence factors, including; outer membrane proteins, efflux pumps, biofilm, penicillin-binding proteins, and siderophores/iron acquisition systems. We reviewed the recent scientific literature on different A. baumannii virulence factors and the effective antimicrobial agents for the treatment and management of bacterial infections.

Carbapenem resistance in Acinetobacter baumannii, and their importance in hospital-acquired infections: a scientific review

Carbapenem is an important therapy for serious hospital-acquired infections and for the care of patients affected by multidrug-resistant organisms, specifically Acinetobacter baumannii; however, with the global increase of carbapenem-resistant A. baumannii, this pathogen has significantly threatened public health. Thus, there is a pressing need to better understand this pathogen in order to develop novel treatments and control strategies for dealing with A. baumannii. In this review, we discuss an overview of carbapenem, including its discovery, development, classification and biological characteristics, and its importance in hospital medicine especially in critical care units. We also describe the peculiarity of bacterial pathogen, A. baumannii, including its commonly reported virulence factors, environmental persistence and carbapenem resistance mechanisms. In closing, we discuss various control strategies for overcoming carbapenem resistance in hospitals and for limiting outbreaks. With the appearance of strains that resist carbapenem, the aim of this review is to highlight the importance of understanding this increasingly problematic healthcare-associated pathogen that creates significant concern in the field of nosocomial infections and overall public health.

Classification of the Gut Microbiota of Patients in Intensive Care Units During Development of Sepsis and Septic Shock

The gut microbiota of intensive care unit (ICU) patients displays extreme dysbiosis associated with increased susceptibility to organ failure, sepsis, and septic shock. However, such dysbiosis is difficult to characterize owing to the high dimensional complexity of the gut microbiota. We tested whether the concept of enterotype can be applied to the gut microbiota of ICU patients to describe the dysbiosis. We collected 131 fecal samples from 64 ICU patients diagnosed with sepsis or septic shock and performed 16S rRNA gene sequencing to dissect their gut microbiota compositions. During the development of sepsis or septic shock and during various medical treatments, the ICU patients always exhibited two dysbiotic microbiota patterns, or ICU-enterotypes, which could not be explained by host properties such as age, sex, and body mass index, or external stressors such as infection site and antibiotic use. ICU-enterotype I (ICU E1) comprised predominantly Bacteroides and an unclassified genus of Enterobacteriaceae, while ICU-enterotype II (ICU E2) comprised predominantly Enterococcus. Among more critically ill patients with Acute Physiology and Chronic Health Evaluation II (APACHE II) scores > 18, septic shock was more likely to occur with ICU E1 (P = 0.041). Additionally, ICU E1 was correlated with high serum lactate levels (P = 0.007). Therefore, different patterns of dysbiosis were correlated with different clinical outcomes, suggesting that ICU-enterotypes should be diagnosed as independent clinical indices. Thus, the microbial-based human index classifier we propose is precise and effective for timely monitoring of ICU-enterotypes of individual patients. This work is a first step toward precision medicine for septic patients based on their gut microbiota profiles.

Recent molecules in the treatment of severe infections caused by ESBL-producing bacteria

Introduction: The widespread increase in resistance to β-lactam antibiotics in Enterobacterales currently represents one of the main threats to human health worldwide. The primary mechanisms of resistance are the production of β-lactamase enzymes that are able to hydrolyze β-lactams.Areas covered: we summarize the most recent advances regarding the main characteristics and spectrum of activity of new available antibiotics and strategies for the treatment of ESBL-producing Enterobacterales infections.Expert opinion: ESBL-producing strains are recognized as a worldwide challenge in the treatment of both hospital- and community-acquired infections. Data from the literature point out the high mortality associated with severe infections due to ESBL strains, especially in patients who developed severe sepsis or septic shock, together with the importance of the source of infection and indicators of severity, as determinants of the patient's outcome. Carbapenems are currently considered the first-line therapy, although the diffusion of resistant strains is an evolving problem and is mandatory the introduction in clinical practice of new drug regimens and treatment strategies, based on clinical data, local epidemiology, and microbiology. As a possible carbapenem-sparing strategy, ceftolozane-tazobactam and ceftazidime-avibactam appear the best-available carbapenem-sparing therapies. The definitive role of new drugs should be definitively assessed.

Gram-negative bacilli bacteremia: a 7 year retrospective study in a referral Brazilian tertiary-care teaching hospital

Introduction. Bloodstream infection is one of the most frequent and challenging hospital-acquired infections and it is associated with high morbidity, mortality and additional use of healthcare resources.Hypothesis/Gap Statement: Bloodstream infections have consequences for the patient, such as the evolution to mortality and inappropriate empirical antibiotic prescription, especially when caused by multidrug-resistant Gram-negative bacilli.Objective. To assess the impact of bloodstream infection and the status of multidrug resistance (MDR) in the evolution of patients who received inappropriate initial antibiotic therapy.Methods. A retrospective surveillance was conducted on nosocomial bloodstream infections caused by Gram-negative bacilli (GNB) from January 2012 to December 2018 in an adult intensive care unit of a Brazilian tertiary teaching hospital.Results. We identified 270 patients with GNB nosocomial bacteremia. Non-survivors were older (with an average age of 58.8 years vs 46.9 years, P=<0.0001), presented more severe illnesses, were immunosuppressed (73.7 vs 37.6%, P=<0.0001), were more likely to have septic shock (55.8 vs 22.4%, P=<0.0001) and had an increased usage of mechanical ventilators (98.6 vs 89.6%, P=0.0013) than survivors. In a logistic regression model, inappropriate empirical antibiotic therapy was not an independent predictor of mortality, different from mechanical ventilator (P=<0.0001; OR=28.0; 95% CI=6.3-123.6), septic shock (P=0.0051; OR=2.5; 95% CI=1.3-4.9) and immunosuppression (P=0.0066; OR=2.6; 95% CI=1.3-5.2). In contrast, in a separate model, MDR was strongly associated with the prescription of inappropriate initial antibiotic therapy (P=0.0030; OR=5.3; 95% CI=1.7-16.1). The main isolated pathogens were Acinetobacter baumannii (23.6 %) and Klebsiella pneumoniae (18.7 %). The frequency of MDR organisms was high (63.7 %), especially among non-fermenting bacilli (60.9 %), highlighting A. baumannii (81.6 %) and Pseudomonas aeruginosa (41.8 %).Conclusion. Illness severity (septic shock and immunosuppression) and mechanical ventilation were identified as predictors of mortality. Additionally, MDR was a major determinant of inappropriate antibiotic empirical therapy, but not associated with mortality, and both characteristics were not statistically associated with death.

Opportunities for antimicrobial stewardship among carbapenem-treated patients in 18 North American hospitals

Here we describe the characteristics of carbapenem use at 18 hospitals across North America. Adult inpatients treated with a carbapenem for ≥24 h were included in this multicentre, retrospective, cross-sectional study. Outcomes evaluated included classification of therapy as empirical or definitive, discharge disposition and 30-day re-admission. A total of 621 patients were included in this study. Of these, 467 patients (75.2%) received a carbapenem empirically, among whom negative cultures occurred in 313 (67.0%) and 93% were eligible for de-escalation of therapy. In-hospital mortality occurred in 72 patients (11.6%) and 549 patients (88.4%) were discharged. Of the 549 patients who were discharged, 349 patients (63.6%) went home and 30-day infection-related re-admission occurred in 95 patients (17.3%). This population represents a significant need for carbapenem stewardship. Institutional guidelines should focus on four common disease states (respiratory, genitourinary, intra-abdominal and bloodstream), and diagnostic stewardship should be employed to aid in rapid de-escalation of carbapenem therapy. Additional studies aiming to identify antimicrobial stewardship techniques that may help to optimise carbapenem therapy and increase education about the importance of utilising carbapenem-sparing regimens are required.