Activity of ceftolozane-tazobactam and comparators against gram-negative bacilli: Results from the study for monitoring antimicrobial resistance trends (SMART - Brazil; 2016-2017)

Antimicrobial susceptibility of gram-negative bacteria: Analysis from patients in a laboratory network in Brazil

OBJECTIVES

This study aimed to describe the epidemiology and antimicrobial susceptibility patterns of gram-negative pathogens in Brazil from 2018 to 2020, addressing the gap in national data on healthcare-associated infections, using information from a private laboratory network.

METHODS

A cross-sectional study was conducted using a database from Fleury hospital network, a private laboratory in Brazil. The analysis included blood, urine, and lower respiratory tract samples collected from January 2018 to June 2020. The study included consecutive non-duplicated isolates of Enterobacterales or P. aeruginosa from inpatients aged ≥18 years old. Bacterial identification was performed using mass spectrometry, and antimicrobial susceptibility was determined following EUCAST/BrCAST guidelines.

RESULTS

A total of 25,180 isolates were included in the analysis. Most of the sample consisted of female patients (57.9%), with a mean age of 70 years (SD 18.1). Enterobacterales were the most prevalent pathogens found (76.2%), while P. aeruginosa was present in the remaining 23.8%. In terms of antimicrobial susceptibility, Enterobacterales exhibited a higher susceptibility rate to ceftazidime/avibactam (97.1%) and amikacin (95.6%), while P. aeruginosa showed a higher susceptibility rate to polymyxin B (97.1%) and ceftolozane/tazobactam (86.6%). Among carbapenem-resistant P. aeruginosa isolates, 75% were susceptible to ceftolozane/tazobactam. Additionally, 24.2% of K. pneumoniae complex samples were identified.

CONCLUSION

Enterobacterales was the most frequently encountered group in Brazil. Ceftazidime/avibactam and amikacin demonstrated the highest efficacy against this group, while ceftolozane/tazobactam and polymyxin had the highest efficacy against P. aeruginosa. This highlights the importance of new β-lactam-β-lactamase inhibitor combinations for the treatment of gram-negative infections.

Activity of ceftolozane/tazobactam and comparators against gram-negative bacilli: Results from the Study for Monitoring Antimicrobial Resistance Trends (SMART - Brazil), 2018‒2021

Increased spread of antimicrobial resistance by Gram-Negative Bacilli (GNB) poses a global challenge, with exacerbated burden post-pandemic. The aim of this study was to investigate the in vitro activity of ceftolozane/tazobactam and its comparators against the frequently identified GNB isolated from patients admitted to Brazilian medical sites between the year 2018‒2019 and 2020‒2021. The impact of pandemic on antimicrobial resistance and presence of β-lactamase genes were also evaluated. Antimicrobial susceptibility testing and molecular characterization of ß-lactamase encoding genes using Polymerase Chain Reaction (PCR) and DNA sequencing were carried out from GNB isolated mostly from intra-abdominal, respiratory, and urinary tract infections and interpreted following BrCAST/EUCAST guidelines. A total of 3994 GNB isolates were evaluated which mostly included E. coli, K. pneumoniae and P. aeruginosa. Ceftolozane/tazobactam remained highly active against E. coli isolates during both 2018‒2019 (96.0 %) and 2020‒2021 (98.5 %). Among K. pneumoniae, ceftolozane/tazobactam (47.6 % and 43.0 % susceptible during 2018‒2019 and 2020‒2021, respectively) showed poor activity due to blaKPC-2. Colistin and ceftolozane/tazobactam were the most active β-lactam agents tested against P. aeruginosa in 2018‒2019 (99.3 % and 88.8 %) and 2020‒2021 (100 % and 92.8 %), including ceftazidime and meropenem resistant isolates. β-lactamase encoding gene characterization was carried out and both carbapenemases and Extended-Spectrum β-Lactamase (ESBL) producers were found in E. coli, K. pneumoniae and P. aeruginosa isolates. Ceftolozane/tazobactam documented remarkable in vitro activity against E. coli and P. aeruginosa isolates in Brazil, both pre- and post-pandemic periods and could constitute an effective therapeutic option for the treatment of urinary tract infections, intra-abdominal infections, and respiratory tract infections.

Systematic review and meta-analysis on antimicrobial resistance and drug resistance in Saudi Arabia

BACKGROUND

Antimicrobial resistance (AMR) and drug resistance have emerged as major global health concerns, threatening the effectiveness of antimicrobial agents and compromising patient outcomes [21]. The rapid spread of resistant pathogens poses significant challenges to healthcare systems worldwide, leading to increased morbidity, mortality, and healthcare costs [20].

METHODS

  SEARCH STRATEGY: To find pertinent studies released up until September 2023, a thorough search was done in electronic databases like PubMed, Embase, and Scopus. The search method combined terms linked to Saudi Arabia, drug resistance, and antimicrobial resistance (AMR). The specific search terms and Boolean operators used were tailored to the requirements and functionalities of each database.

RESULTS

The systematic review includes 25 papers in total, representing various Saudi Arabian healthcare environments and patient groups. The prevalence of AMR varied across different pathogens and antimicrobial agents. The most resistant Enterobacteriaceae were carbapenem-resistant Enterobacteriaceae (CRE), extended-spectrum -lactamase-producing Enterobacteriaceae (ESBL), and methicillin-resistant Staphylococcus aureus (MRSA). The full manuscript will report the pooled prevalence rates and 95% CIs for each resistance type. The rates for such bacteria were 38.7%, 26.4%, and 15.2% respectively suggesting an imminent need for improvement in surveillance measures & interventions to reduce the burden of AMR (Antimicrobial Resistance).

CONCLUSION

The prevalence of antibiotic resistance (AMR) is alarmingly high in Saudi Arabia. The aim of this study was to examine the prevalence of AMR across different types of pathogens and antimicrobial agents. A meta-analysis was conducted to quantify the pooled prevalence of each type of resistance across hospitals, environments, and food samples from Saudi Arabian locations. The study identified three types of resistance: carbapenem-resistant Enterobacteriaceae (CRE), extended-spectrum -lactamaseproducing Enterobacilli (ESBL), and methicillin-resistant Staphylococcus aureus (MRSA). Furthermore, the study identified several risk factors associated with AMR, including prior antibiotic use, healthcare-associated infections, and prolonged hospital stays.

Detoxification Mechanism of Hinokitiol by Alternaria alternata and Its Application in Agricultural Antifungal Control

Alternaria alternata is a common plant pathogen that can infect crops and reduce their production. In this work, an antagonism experiment between A. alternata and the essential oil of arborvitae (Platycladus orientalis) was performed, and it was proven that A. alternata had developed resistance to this plant-derived fungicide. A. alternata facilitated the biotransformation of hinokitiol (1), the main antifungal compound in the essential oil of arborvitae, into (R)-2-hydroxy-β-methylbenzeneethanol (2), which does not have antifungal activity against A. alternata. This biotransformation is an unusual ring-contraction reaction that was verified to be catalyzed by P450 enzyme hydroxylation and Baeyer-Villiger oxidation. In addition, the P450 enzyme inhibitors 1-aminobenzotriazole and piperonyl butoxide effectively prevented the destruction of the hinokitiol structure by A. alternata, and the combined use of these P450 enzyme inhibitors significantly increased the antifungal activity of hinokitiol. This work provides a theoretical reference for the further development of botanical fungicides.

Polymyxin combination therapy for multidrug-resistant, extensively-drug resistant, and difficult-to-treat drug-resistant gram-negative infections: is it superior to polymyxin monotherapy?

INTRODUCTION

The increasing prevalence of infections with multidrug-resistant (MDR), extensively-drug resistant (XDR) or difficult-to-treat drug resistant (DTR) Gram-negative bacilli (GNB), including Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Enterobacter species, and Escherichia coli poses a severe challenge.

AREAS COVERED

The rapid growing of multi-resistant GNB as well as the considerable deceleration in development of new anti-infective agents have made polymyxins (e.g. polymyxin B and colistin) a mainstay in clinical practices as either monotherapy or combination therapy. However, whether the polymyxin-based combinations lead to better outcomes remains unknown. This review mainly focuses on the effect of polymyxin combination therapy versus monotherapy on treating GNB-related infections. We also provide several factors in designing studies and their impact on optimizing polymyxin combinations.

EXPERT OPINION

An abundance of recent in vitro and preclinical in vivo data suggest clinical benefit for polymyxin-drug combination therapies, especially colistin plus meropenem and colistin plus rifampicin, with synergistic killing against MDR, XDR, and DTR P. aeruginosa, K. pneumoniae and A. baumannii. The beneficial effects of polymyxin-drug combinations (e.g. colistin or polymyxin B + carbapenem against carbapenem-resistant K. pneumoniae and carbapenem-resistant A. baumannii, polymyxin B + carbapenem + rifampin against carbapenem-resistant K. pneumoniae, and colistin + ceftolozan/tazobactam + rifampin against PDR-P. aeruginosa) have often been shown in clinical setting by retrospective studies. However, high-certainty evidence from large randomized controlled trials is necessary. These clinical trials should incorporate careful attention to patient's sample size, characteristics of patient's groups, PK/PD relationships and dosing, rapid detection of resistance, MIC determinations, and therapeutic drug monitoring.

Global evaluation of the antibacterial activity of Ceftolozane/Tazobactam against ESBLs-producing Escherichia coli and Klebsiella pneumoniae: a systematic review and meta-analysis

Background

Ceftolozane/Tazobactam is a β-lactam/β-lactamase inhibitor combination with a high range of efficacy and broad-spectrum action against multidrug-resistant bacterial strains.

Objectives

The present study aimed to analyze the in vitro activity of Ceftolozane/Tazobactam against extended-spectrum β-lactamases (ESBLs)-producing Escherichia coli (ESBLs-EC) and Klebsiella pneumonia (ESBLs-KP) in the published literature to provide international data on the antimicrobial stewardship programs.

Design

Systematic review and meta-analysis.

Methods

A systematic literature search was conducted on the Web of Science, Embase, PubMed, Scopus, and Google Scholar electronic databases from the beginning of databases to December 2022 to cover all published articles relevant to our scope.

Results

At last, 31 publications that met our inclusion criteria were selected for data extraction and analysis by Comprehensive Meta-Analysis Software. The pooled prevalence of Ceftolozane/Tazobactam susceptibility for ESBLs-EC and ESBLs-KP was estimated at 91.3% [95% confidence interval (CI): 90.1-92.5%] and 65.6% (95% CI: 60.8-70.2%), respectively. There was significant heterogeneity among the 31 studies for ESBLs-EC (χ2 = 91.621; p < 0.001; I2 = 67.256%) and ESBLs-KP (χ2 = 348.72; p < 0.001; I2 = 91.4%). Most clinical isolates of ESBLs-EC had MIC50 and MIC90 at a concentration of 0.5 and 2 µg/mL [minimum inhibitory concentration (MIC) at which 50% and 90% of isolates were inhibited], respectively. In contrast, most clinical isolates of ESBLs-KP had MIC50 and MIC90 at a concentration of 1 and 32 µg/mL, respectively.

Conclusion

Based on the meta-analysis results, Ceftolozane/Tazobactam has a more promising in vitro antibacterial activity against ESBLs-EC isolates from different clinical sources than ESBLs-KP isolates. Therefore, Ceftolozane/Tazobactam can be a useful therapeutic drug as an alternative to carbapenems. Randomized clinical trials are needed to provide clinical evidence to support these observations.

Global Prevalence and Molecular Epidemiology of mcr-Mediated Colistin Resistance in Escherichia coli Clinical Isolates: A Systematic Review

BACKGROUND AND AIM

The continuing rise in infections caused by multi-drug resistant (MDR) bacteria is one of the most serious public health issues in today's societies. Colistin is a last-resort antimicrobial medication used to treat infections caused by MDR gram-negative bacteria; therefore resistance to this antibiotic is extremely hazardous. The current study aimed to evaluate the global prevalence and distribution of colistin resistance genes among human clinical isolates of Escherichia coli (E. coli) as a systematic review.

METHODS

PubMed, Embase, and Web of Science databases were systematically searched. For further evaluation, all original English-language articles that demonstrated colistin resistance in E. coli clinical isolates published between 2000 and 2020 were examined.

RESULTS

Out of 4857 initial articles, after various stages of review and evaluation, 190 related articles were selected. More than 79 % of the publications selected in this research were published from 2014 to 2020. In Asia, Europe, America, Africa, and Oceania, the prevalence of mobilized colistin resistance (mcr) producing colistin-resistant E. coli was 66.72%, 25.48%, 5.19%, 2.27%, and 0.32 %, respectively.

CONCLUSION

The recent widespread spreading of E. coli strains harboring mcr conferring colistin resistance, especially in Asia and Europe, is concerning and needs more attention.

Virulence Genes Profile and Antimicrobial Susceptibility of Community-Acquired Bacterial Urinary Tract Infections in a Brazilian Hospital

Urinary tract infections (UTI) are one of the most common diseases worldwide and Escherichia coli is the most common causative bacteria. Empirical treatment is challenging due to antimicrobial or multidrug-resistance. The aims of this study were to determine the uropathogens and their antimicrobial susceptibility profile, as well as to identify the phylogroups and virulence genes of E. coli strains, associated with community-acquired UTI in outpatients admitted at a Brazilian Hospital in southeast Brazil. In total, 47 bacterial strains were isolated from 47 patients, 44 women and 2 men (no gender record from one patient). The age of the patients whose urine culture were positive varied from 0 (less than one month) to 104 years. Most of the isolates were E. coli (41/47), followed by Klebsiella pneumoniae (2/47), Klebsiella variicola/Klebsiella aerogenes (1/47), Pseudomonas aeruginosa (1/47), Proteus mirabilis (1/47), and Citrobacter koseri (1/47). Most E. coli strains were classified as phylogroup B2 (15/41 = 36.59%) and B1 (12/41 = 29.27%) and the most common virulence genes among E. coli strains were fimH (31/41 = 75.61%), iutA (21/41 = 51.22%), and tratT (16/41 = 39.02%). Among the E. coli strains, 59% were multidrug-resistance and strains that were ampicillin, sulfamethoxazole/trimethoprim, or tetracycline-resistant exhibited more chance to be multidrug-resistance, with an odds ratio of 100.00 [95% confidence interval (CI) 9.44-1059.26], 22.50 (95% CI 3.95-128.30), and 12.83 (95% CI 2.68-61.45), respectively. Our results showed that E. coli was the main etiological agent identified and demonstrated high frequency of multidrug-resistance and virulence factors in bacterial strains isolated from UTIs.

Antimicrobial activity of ceftolozane-tazobactam against Enterobacterales and Pseudomonas aeruginosa recovered during the Study for Monitoring Antimicrobial Resistance Trends (SMART) program in Spain (2016-2018)

OBJECTIVE

To analyse the susceptibility to ceftolozane-tazobactam and comparators in Enterobacterales and Pseudomonas aeruginosa isolates recovered from intraabdominal (IAI), urinary (UTI), respiratory (RTI) and bloodstream infection (BSI) in the SMART (Study for Monitoring Antimicrobial Resistance Trends) study.

METHODS

The susceptibility of 5,351 isolates collected in 11 Spanish hospitals (2016-2018) were analysed (EUCAST-2020 criteria) by broth microdilution and were phenotypically studied for the presence of extended-spectrum beta-lactamases (ESBL). Ceftolozane-tazobactam and/or carbapenem resistant isolates were genetically characterized for ESBL and carbapenemases.

RESULTS

Escherichia coli was the most frequent pathogen (49.3% IAI, 54.9% UTI, 16.7% RTI and 50% BSI), followed by Klebsiella pneumoniae (11.9%, 19.1%, 13.1% and 15.4%, respectively). P. aeruginosa was isolated in 9.3%, 5.6%, 32% and 9%, respectively. The frequency of isolates with ESBLs (2016-2017) was: 30.5% K. pneumoniae, 8.6% E. coli, 2.3% Klebsiella oxytoca and 0.7% Proteus mirabilis. Ceftolozane-tazobactam was very active against non-ESBL-(99.3% susceptible) and ESBL-(95.2%) producing E. coli being less active against K. pneumoniae (98% and 43.1%, respectively) isolates. CTX-M-15 was the most prevalent ESBL in E. coli (27.5%) and K. pneumoniae (51.9%) frequently associated with OXA-48-like carbapenemase. Overall, 93% of P. aeruginosa isolates were susceptible to ceftolozane-tazobactam, preserving this activity (>75%) in isolates resistant to other beta-lactams except in those resistant to meropenen or ceftazidime-avibactam. GES-5, PER-1, VIM-1/2 were the most prevalent enzymes in isolates resistant to ceftolozane-tazobactam.

CONCLUSIONS

Ceftolozane-tazobactam showed high activity rates against isolates recovered in the SMART study although it was affected in K. pneumoniae and P. aeruginosa isolates with ESBL and/or carbapenemases.

Understanding the binding conformation of ceftolozane/tazobactam with Metallo-β-lactamases VIM-5 and IMP-7 of Pseudomonas aeruginosa: A molecular docking and virtual screening process

Pseudomonas aeruginosa (P. aeruginosa) is one of the community-acquired and healthcare-associated infections causing organisms. It has become resistant to most of the available antibiotics and is termed multi-drug resistance (MDR). There are a limited number of antibiotics are available to treat such MDR organism causing infections. The ceftolozane/tazobactam is one among the combination drug therapy (CDT) prescribed for the treatment of MDR causing infections. The resistance for the same CDT was observed in the MDR P. aeruginosa harboring VIM-5 and IMP-7 Metallo beta (β)-lactamases (MBLs). To explore the resistance mechanism at the molecular level, docking studies were carried out for antibiotics against VIM-5 and IMP-7 MBLs. The Zn2 metal ions carry out the nucleophile attack on the carbonyl carbon of the β-lactam ring along with conserved water molecules. To find lead compounds against the MBLs, a virtual screening process was carried out. We have employed MODELLER for structure modeling, AutoDock for molecular docking and AutoDock Vina, Molinspiration, PASS prediction & admetSAR in virtual screening. The search of low binding energy ceftolozane analogs against VIM-5 and IMP-7 MBLs has resulted in the ZINC000029060075 and ZINC000009163636 analogs. Similarly, the screening of high binding energy inhibitors against VIM-5 and IMP-7 MBLs has resulted in ZINC000003831503 and ZINC000000897247 tazobactam analogs respectively. The ADMET prediction results in the non-toxicity of the lead compounds. Our study may provide new insights for the scientist who are designing novel drugs against MDR P. aeruginosa causing infections.

Prevalence of blaKPC-2, blaKPC-3 and blaKPC-30-Carrying Plasmids in Klebsiella pneumoniae Isolated in a Brazilian Hospital

Klebsiella pneumoniae carbapenemase (KPC) actively hydrolyzes carbapenems, antibiotics often used a last-line treatment for multidrug-resistant bacteria. KPC clinical relevance resides in its widespread dissemination. In this work, we report the genomic context of KPC coding genes bla_KPC-2, bla_KPC-3 and bla_KPC-30 in multidrug-resistant Klebsiellapneumoniae isolates from Brazil. Plasmids harboring bla_KPC-3 and bla_KPC-30 were identified. Fifteen additional carbapenem-resistant K. pneumoniae isolates were selected from the same tertiary hospital, collected over a period of 8 years. Their genomes were sequenced in order to evaluate the prevalence and dissemination of bla_KPC-harboring plasmids. We found that bla_KPC genes were mostly carried by one of two isoforms of transposon Tn4401 (Tn4401a or Tn4401b) that were predominantly located on plasmids highly similar to the previously described plasmid pKPC_FCF3SP (IncN). The identified pKPC_FCF3SP-like plasmids carried either bla_KPC-2 or bla_KPC-30. Two K. pneumoniae isolates harbored pKpQIL-like (IncFII) plasmids, only recently identified in Brazil; one of them harbored bla_KPC-3 in a Tn4401a transposon. Underlining the risk of horizontal spread of KPC coding genes, this study reports the prevalence of bla_KPC-2 and the recent spread of bla_KPC-3, and bla_KPC-30, in association with different isoforms of Tn4401, together with high synteny of plasmid backbones among isolates studied here and in comparison with previous reports.

The role of new antimicrobials for Gram-negative infections in daily clinical practice

PURPOSE OF REVIEW

To discuss a possible clinical reasoning for treating resistant Gram-negative bacteria (GNB) infections in daily clinical practice, as well as developing a research agenda for the field.

RECENT FINDINGS

Novel agents, both belonging to β-lactams and to other classes of antimicrobials, have recently become available, likely replacing polymyxins or polymyxin-based combination regimens as the preferred choices for the first-line treatment of severe resistant GNB infections in the near future.

SUMMARY

The peculiar characteristics of novel agents for severe resistant GNB infections have abruptly made the structure of previous therapeutic algorithms somewhat obsolete, in view of the differential activity of most of them against different classes of carbapenemases. Furthermore, other agents showing activity against resistant GNB are in late phase of clinical development. Optimizing the use of novel agents in order both to guarantee the best available treatment to patients and to delay the emergence and spread of resistance is an important task that cannot be postponed, especially considering the unavailability of well tolerated and fully efficacious options for treating resistant GNB infections that we faced in the last 15 years.