Phage therapeutic delivery methods and clinical trials for combating clinically relevant pathogens

The ongoing global health crisis caused by multidrug-resistant (MDR) bacteria necessitates quick interventions to introduce new management strategies for MDR-associated infections and antimicrobial agents' resistance. Phage therapy emerges as an antibiotic substitute for its high specificity, efficacy, and safety profiles in treating MDR-associated infections. Various in vitro and in vivo studies denoted their eminent bactericidal and anti-biofilm potential. This review addresses the latest developments in phage therapy regarding their attack strategies, formulations, and administration routes. It additionally discusses and elaborates on the status of phage therapy undergoing clinical trials, and the challenges encountered in their usage, and explores prospects in phage therapy research and application.

Overall status of carbapenem resistance among clinical isolates of Acinetobacter baumannii: a systematic review and meta-analysis

BACKGROUND

Resistance to carbapenems, the first-line treatment for infections caused by Acinetobacter baumannii, is increasing throughout the world. The aim of the present study was to determine the global status of resistance to carbapenems in clinical isolates of this pathogen, worldwide.

METHODS

Electronic databases were searched using the appropriate keywords, including: 'Acinetobacter' 'baumannii', 'Acinetobacter baumannii' and 'A. baumannii', 'resistance', 'antibiotic resistance', 'antibiotic susceptibility', 'antimicrobial resistance', 'antimicrobial susceptibility', 'carbapenem', 'carbapenems', 'imipenem', 'meropenem' and 'doripenem'. Finally, following some exclusions, 177 studies from various countries were included in this study. The data were then subjected to a meta-analysis.

RESULTS

The average resistance rate of A. baumannii to imipenem, meropenem and doripenem was 44.7%, 59.4% and 72.7%, respectively. A high level of heterogeneity (I2 > 50%, P value < 0.05) was detected in the studies representing resistance to imipenem, meropenem and doripenem in A. baumannii isolates. Begg's and Egger's tests did not indicate publication bias (P value > 0.05).

CONCLUSIONS

The findings of the current study indicate that the overall resistance to carbapenems in clinical isolates of A. baumannii is relatively high and prevalent throughout the world. Moreover, time trend analysis showed that the resistance has increased from the year 2000 to 2023. This emphasizes the importance of conducting routine antimicrobial susceptibility testing before selecting a course of treatment, as well as monitoring and controlling antibiotic resistance patterns in A. baumannii strains, and seeking novel treatment options to lessen the emergence and spread of resistant strains and to reduce the treatment failure.

Current treatment strategies for targeting virulence factors and biofilm formation in Acinetobacter baumannii

A higher prevalence of Acinetobacter baumannii infections and mortality rate has been reported recently in hospital-acquired infections (HAI). The biofilm-forming capability of A. baumannii makes it an extremely dangerous pathogen, especially in device-associated hospital-acquired infections (DA-HAI), thereby it resists the penetration of antibiotics. Further, the transmission of the SARS-CoV-2 virus was exacerbated in DA-HAI during the epidemic. This review specifically examines the complex interconnections between several components and genes that play a role in the biofilm formation and the development of infections. The current review provides insights into innovative treatments and therapeutic approaches to combat A. baumannii biofilm-related infections, thereby ultimately improving patient outcomes and reducing the burden of HAI.

Discovery of Antimicrobial Agents Based on Structural and Functional Study of the Klebsiella pneumoniae MazEF Toxin-Antitoxin System

Klebsiella pneumoniae causes severe human diseases, but its resistance to current antibiotics is increasing. Therefore, new antibiotics to eradicate K. pneumoniae are urgently needed. Bacterial toxin-antitoxin (TA) systems are strongly correlated with physiological processes in pathogenic bacteria, such as growth arrest, survival, and apoptosis. By using structural information, we could design the peptides and small-molecule compounds that can disrupt the binding between K. pneumoniae MazE and MazF, which release free MazF toxin. Because the MazEF system is closely implicated in programmed cell death, artificial activation of MazF can promote cell death of K. pneumoniae. The effectiveness of a discovered small-molecule compound in bacterial cell killing was confirmed through flow cytometry analysis. Our findings can contribute to understanding the bacterial MazEF TA system and developing antimicrobial agents for treating drug-resistant K. pneumoniae.

Antibiotic resistances of Pseudomonas aeruginosa and Acinetobacter baumannii in urine cultures: experience in a hospital of Southeast Spain

The objectives of this study were to perform a systematic review of publications between 2010 and 2021 on the antibiotic resistance of Pseudomonas aeruginosa and Acinetobacter baumannii from urinary tract infections and to analyze changes over time in hospital urine cultures from 2016 through 2021. The literature was searched, and a retrospective cross-sectional descriptive study was performed in the hospital. Out of 21 838 positive urine cultures, 3.86% were due to P. aeruginosa and 0.44% were due to A. baumannii. For P. aeruginosa, lower resistance rates were observed to virtually all tested antibiotics than were obtained in the systematic review, and the present series of hospital samples showed an in vitro resistance rate <10% to ceftazidime, cefepime, meropenem, piperacillin-tazobactam, amikacin, tobramycin, and colistin. For A. baumannii, the resistance rates to almost all antibiotics were higher in the present series than in the systematic review, being lowest to colistin (10%). Both microorganisms show reduced in vitro susceptibility to some antibiotics during the years of the COVID-19 pandemic in comparison to previous years. In our setting, both piperacillin-tazobactam and meropenem can be recommended for the empirical treatment of UTIs by P. aeruginosa, whereas only colistin can be recommended for UTIs by A. baumannii.

A novel strategy to characterize the pattern of β-lactam antibiotic-induced drug resistance in Acinetobacter baumannii

Carbapenem-resistant Acinetobacter baumannii (CRAb) is an urgent public health threat, according to the CDC. This pathogen has few treatment options and causes severe nosocomial infections with > 50% fatality rate. Although previous studies have examined the proteome of CRAb, there have been no focused analyses of dynamic changes to β-lactamase expression that may occur due to drug exposure. Here, we present our initial proteomic study of variation in β-lactamase expression that occurs in CRAb with different β-lactam antibiotics. Briefly, drug resistance to Ab (ATCC 19606) was induced by the administration of various classes of β-lactam antibiotics, and the cell-free supernatant was isolated, concentrated, separated by SDS-PAGE, digested with trypsin, and identified by label-free LC-MS-based quantitative proteomics. Thirteen proteins were identified and evaluated using a 1789 sequence database of Ab β-lactamases from UniProt, the majority of which were Class C β-lactamases (≥ 80%). Importantly, different antibiotics, even those of the same class (e.g. penicillin and amoxicillin), induced non-equivalent responses comprising various isoforms of Class C and D serine-β-lactamases, resulting in unique resistomes. These results open the door to a new approach of analyzing and studying the problem of multi-drug resistance in bacteria that rely strongly on β-lactamase expression.

Participant- and Disease-Related Factors as Independent Predictors of Treatment Outcomes in the RESTORE-IMI 2 Clinical Trial: A Multivariable Regression Analysis

Background

In the RESTORE-IMI 2 trial, imipenem/cilastatin/relebactam (IMI/REL) was noninferior to piperacillin/tazobactam in treating hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia. This post hoc analysis was conducted to determine independent predictors of efficacy outcomes in the RESTORE-IMI 2 trial, to assist in treatment decision making.

Methods

A stepwise multivariable regression analysis was conducted to identify variables that were independently associated with day 28 all-cause mortality (ACM), favorable clinical response at early follow-up (EFU), and favorable microbiologic response at end of treatment (EOT). The analysis accounted for the number of baseline infecting pathogens and in vitro susceptibility to randomized treatment.

Results

Vasopressor use, renal impairment, bacteremia at baseline, and Acute Physiologic Assessment and Chronic Health Evaluation (APACHE) II scores ≥15 were associated with a greater risk of day 28 ACM. A favorable clinical response at EFU was associated with normal renal function, an APACHE II score <15, no vasopressor use, and no bacteremia at baseline. At EOT, a favorable microbiologic response was associated with IMI/REL treatment, normal renal function, no vasopressor use, nonventilated pneumonia at baseline, intensive care unit admission at randomization, monomicrobial infections at baseline, and absence of Acinetobacter calcoaceticus-baumannii complex at baseline. These factors remained significant after accounting for polymicrobial infection and in vitro susceptibility to assigned treatment.

Conclusions

This analysis, which accounted for baseline pathogen susceptibility, validated well-recognized patient- and disease-related factors as independent predictors of clinical outcomes. These results lend further support to the noninferiority of IMI/REL to piperacillin/tazobactam and suggests that pathogen eradication may be more likely with IMI/REL.

Clinical Trials Registration

NCT02493764.

Multi-drug resistant ESKAPE pathogens and the uses of plants as their antimicrobial agents

Infections by ESKAPE (Enterococcus sp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pathogens cause major concern due to their multi-drug resistance (MDR). The ESKAPE pathogens are frequently linked to greater mortality, diseases, and economic burden in healthcare worldwide. Therefore, the use of plants as a natural source of antimicrobial agents provide a solution as they are easily available and safe to use. These natural drugs can also be enhanced by incorporating silver nanoparticles and combining them with existing antibiotics. By focussing the attention on the ESKAPE organisms, the MDR issue can be addressed much better.

A novel strategy to characterize the pattern of β-lactam antibiotic-induced drug resistance in Acinetobacter baumannii

Carbapenem-resistant Acinetobacter baumannii (CRAb) is an urgent public health threat, according to the CDC. This pathogen has few treatment options and causes severe nosocomial infections with > 50% fatality rate. Although previous studies have examined the proteome of CRAb, there have been no focused analyses of dynamic changes to β-lactamase expression that may occur due to drug exposure. Here, we present our initial proteomic study of variation in β-lactamase expression that occurs in CRAb with different β-lactam antibiotics. Briefly, drug resistance to Ab (ATCC 19606) was induced by the administration of various classes of β-lactam antibiotics, and the cell-free supernatant was isolated, concentrated, separated by SDS-PAGE, digested with trypsin, and identified by label-free LC-MS-based quantitative proteomics. Peptides were identified and evaluated using a 1789 sequence database of Ab β-lactamases from UniProt. Importantly, we observed that different antibiotics, even those of the same class ( e.g. penicillin and amoxicillin), induce non-equivalent responses comprising various Class C and D serine-β-lactamases, resulting in unique resistomes. These results open the door to a new approach of analyzing and studying the problem of multi-drug resistance in bacteria that rely strongly on β-lactamase expression.

A high-efficiency scar-free genome-editing toolkit for Acinetobacter baumannii

BACKGROUND

The current mutagenesis tools for Acinetobacter baumannii leave selection markers or residual sequences behind, or involve tedious counterselection and screening steps. Furthermore, they are usually adapted for model strains, rather than for MDR clinical isolates.

OBJECTIVES

To develop a scar-free genome-editing tool suitable for chromosomal and plasmid modifications in MDR A. baumannii AB5075.

METHODS

We prove the efficiency of our adapted genome-editing system by deleting the multidrug efflux pumps craA, cmlA5 and resistance island 2 (RI2), as well as curing plasmid p1AB5075, and combining these mutations. We then characterized the susceptibility of the mutants compared with the WT to different antibiotics (i.e. chloramphenicol, amikacin and tobramycin) by disc diffusion assays and determined the MIC for each strain.

RESULTS

We successfully adapted the genome-editing protocol to A. baumannii AB5075, achieving a double recombination frequency close to 100% and routinely securing the construction of a mutant within 10 working days. Furthermore, we show that both CraA and p1AB5075 are involved in chloramphenicol resistance, and that RI2 and p1AB5075 play a role in resistance to amikacin and tobramycin.

CONCLUSIONS

We have developed a versatile and highly efficient genome-editing tool for A. baumannii. We have demonstrated it can be used to modify both the chromosome and native plasmids. By challenging the method, we show the role of CraA and p1AB5075 in antibiotic resistance.

Influence of Taijiquan Exercise on Mentality and Emotion Regulation by Intelligent Medical Big Data Analysis

Taijiquan training emphasizes the relaxation of the mind and the body, pay attention to maintain the peace of mind, and minimize the impact of external interference on the body so as to make the mind more comfortable. This study mainly explores the influence of Taijiquan practice on emotion regulation based on intelligent medical health big data analysis. The significance of Taijiquan in developing and improving the positive emotions of middle-aged people and maintaining physical and mental health is expounded. There are two methods of data collection: full collection and incremental collection. In this study, when the psychological testing equipment was launched, a full amount of historical data was collected; after the psychological testing equipment was online, the collection method was generally carried out in the way of incremental collection. The subjects exercised Taijiquan three times a week, one hour each time, and the exercise content was the 24-style Taijiquan designated by the workstation. At the same time, the subjects were asked not to engage in other regular physical exercise projects in their spare time. By longitudinal tracking and comparison of the Taijiquan intervention group after participating in the Taijiquan exercise intervention, the differences in the state of mind and emotion regulation strategies, and 12 subjects were selected voluntarily to participate in the emotional Stroop (the color words used in the classic Stroop paradigm were replaced with emotional and nonemotional words written in different colors, and the subjects were still tasked with responding to colors) experimental paradigm. In this paper, the moderate-intensity Taijiquan project is selected, which is in line with the effective value threshold theory of exercise load. It studies the effects of exercise on the body shape, cardiopulmonary function, flexibility, and balance ability of the body according to the metabolism theory and the movement balance theory of the human body adapting to the environment. Before the experiment, there was no significant difference between the Taijiquan training group and the control group, but after the experiment, there was a significant difference between the Taijiquan training group and the control group (P<0.05). Taijiquan has a significant effect on improving students' body shape, cardiopulmonary function, flexibility, balance, and mood.

Molecular Characterization of Gene-Mediated Resistance and Susceptibility of ESKAPE Clinical Isolates to Cistus monspeliensis L. and Cistus salviifolius L. Extracts

Background

Multidrug resistance (MDR) and extensively drug-resistant (XDR) are now the biggest threats to human beings. Alternative antimicrobial regimens to conventional antibiotic paradigms are extensively searched. Although Cistus extracts have long been used for infections in traditional folk medicines around the world, their efficacy against resistant bacteria still needs to be elucidated. We aim to investigate the antibiotic susceptibility profiles of clinical strains Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae (acronym “ESKAPE”), and their resistance mechanisms by PCR, as well as their sensitivity to C. monspeliensis (CM) and C. salviifolius (CS) methanol extracts and their fractions.

Methods

Antibiotic susceptibility profile and resistance mechanism were done by antibiogram and PCR. Fractions of CM and CS were obtained using maceration and Soxhlet; their antibacterial activities were evaluated by determining inhibition zone diameter (IZD), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC).

Results

Results revealed that all strains were XDR except S. aureus, which was MDR. The PCR indicates the presence of gene-mediated resistance (bla_CTX-M, bla_SHV, bla_OXA-48, bla_NDM, bla_OXA-51, bla_OXA-58, bla_IMP, bla_VIM, and bla_mecA). Also, maceration was slightly better for bioactivity preservation. Overall, the extracts of CM (IZD = 20 mm, MIC = 0.01 mg/mL) were more active than those of CS. All extracts inhibited MRSA (methicillin-resistant Staphylococcus aureus) and ERV (Enterococcus faecium Vancomycin-Resistant) with interesting MICs. The ethyl acetate fraction manifested great efficacy against all strains. Monoterpene hydrocarbons and sesquiterpenes oxygenated were the chemical classes of compounds dominating the analyzed fractions. Viridiflorol was the major compound in ethyl acetate fractions of 59.84% and 70.77% for CM and CS, respectively.

Conclusions

The superior activity of extracts to conventional antibiotics was seen for the first time in the pathogens group, and their bactericidal effect could be a promising alternative for developing clinical antibacterial agents against MDR and XDR ESKAPE bacteria.

Evaluation of genetic diversity of colistin-resistant Acinetobacter baumannii by BOX-PCR and ERIC-PCR: the first report

Aim: To control the spread of Acinetobacter baumannii in hospitals, it is necessary to identify the reservoir of organisms and the way they are transmitted. This study analyzed samples by BOX-PCR and enterobacterial repetitive intergenic consensus PCR techniques. Methods: Isolated strains were identified using the Microgen kit and blaOXA-51 gene. The genetic diversity of strains that were sensitive or resistant to colistin was evaluated by BOX-PCR and enterobacterial repetitive intergenic consensus PCR methods. Results: A total of 13% of the isolates were resistant to colistin, whereas 87% of the strains were sensitive to this medication. A. baumannii strains that were resistant or sensitive to colistin were divided into five groups using the BOX-PCR method and six groups using the enterobacterial repetitive intergenic consensus PCR method. Conclusion: Rapid identification and the use of appropriate tools to control colistin-resistant clones are essential to prevent the further spread of A. baumannii.

Design and synthesis of hybrid compounds as novel drugs and medicines

The development of highly effective conjugate chemistry approaches is a way to improve the quality of drugs and of medicines. The aim of this paper is to highlight and review such hybrid compounds and the strategies underpinning their design. A variety of unique hybrid compounds provide an excellent toolkit for novel biological activity, e.g. anticancer and non-viral gene therapy (NVGT), and as templates for killing bacteria and preventing antibiotic drug resistance. First we discuss the anticancer potential of hybrid compounds, containing daunorubicin, benzyl- or tetrahydroisoquinoline-coumarin, and cytotoxic NSAID-pyrrolizidine/indolizine hybrids, then NVGT cationic lipid-based delivery agents, where steroids or long chain fatty acids as the lipid moiety are bound to polyamines as the cationic moiety. These polyamines can be linear as in spermidine or spermine, or on a polycyclic sugar template, aminoglycosides kanamycin and neomycin B, the latter substituted with six amino groups. They are highly efficient for the delivery of both fluorescent DNA and siRNA. Molecular precedents can be found for the design of hybrid compounds in the natural world, e.g., squalamine, the first representative of a previously unknown class of natural antibiotics of animal origin. These polyamine-bile acid (e.g. cholic acid type) conjugates display many exciting biological activities with the bile acids acting as a lipidic region and spermidine as the polycationic region. Analogues of squalamine can act as vectors in NVGT. Their natural role is as antibiotics. Novel antibacterial materials are urgently needed as recalcitrant bacterial infection is a worldwide problem for human health. Ribosome inhibitors founded upon dimers of tobramycin or neomycin, bound as ethers by a 1,6-hexyl linker or a more complex diether-disulfide linker, improved upon the antibiotic activity of aminoglycoside monomers by 20- to 1200-fold. Other hybrids, linked by click chemistry, conjugated ciprofloxacin to neomycin, trimethoprim, or tedizolid, which is now in clinical trials.

Monitoring and Analysis of Youth Sports Physique by Intelligent Medical Robot Based on Cognitive Computing

As a key part of promoting the physical health of the people and promoting social progress, sports has ushered in comprehensive vitality. More and more people's attention has been paid to the physical health status, especially the physical status of young people. In the field of physical fitness monitoring, although the state has continuously increased investment in human and financial resources, it still cannot meet the needs of the market. This study mainly discusses the monitoring of youth sports physique by intelligent medical robots based on cognitive computing. This study introduces the development and implementation process of the management system and the test planning of the system. It focuses on the realization of the scalable architecture of the system server application and the communication mechanism of the intelligent terminal application. With the development of collaborative computing, social computing, and the ever-changing demands of human-computer interaction, it is difficult for a single user to take into account the interactive tasks in complex scenarios. The collaborative interaction of multiusers has gradually been paid more and more attention. Teenagers can log in to the intelligent medical robot system or mobile phone terminal to make health test appointments, score inquiries, and prescription inquiries. Its display module displays different contents according to different login identities. For teenagers, it is necessary to check personal physical test results and have a position on their physical health. Through the intelligent medical robot system, the administrator records and analyzes the results of the youth health test and gives appropriate exercise prescriptions for the youth. This not only analyzes the functional requirements that meet the basic user needs, but also analyzes the nonfunctional requirements that meet the most basic security, stability, and robustness of the software. Intelligent medical systems can effectively help people learn medical knowledge better in today's postepidemic era. It also helps people to conduct self-diagnosis and self-examination of minor diseases to a certain extent, so as to improve their own health. From the functional requirements, each module of the intelligent medical robot system is functionally described. From a nonfunctional point of view, the design and implementation meet the performance requirements of client-side robustness, maintainability, and stability. Finally, the system architecture of the intelligent medical robot is designed, and the specific database table is given. During the research, 20% of the students believed that their physical condition had been improved through physical health monitoring. The state of national physique can reflect a part of the country's comprehensive national strength to a certain extent. Throughout history, the overall development trend of a society and a country is constrained by the two factors of the group's constitution and economic development. This research will contribute to the physical and mental development of adolescents. The robot designed in this paper meets the requirements of a large number of students' centralized testing and is more accurate, faster, and more convenient.

Antimicrobial Stewardship Programs: A Review of Strategies to Avoid Polymyxins and Carbapenems Misuse in Low Middle-Income Countries

Antibiotics misuse and overuse are concerning issues worldwide, especially in low middle-income countries. These practices contribute to the increasing rates of antimicrobial resistance. One efficient strategy to avoid them is antimicrobial stewardship programs. In this review, we focus on the possible approaches to spare the prescription of polymyxins and carbapenems for the treatment of Acinetobacter baumannii, carbapenem-resistant Enterobacterales, and Pseudomonas aeruginosas infections. Additionally, we highlight how to implement cumulative antibiograms and biomarkers to a sooner de-escalation of antibiotics.

In Vitro Activity of Ceftolozane/Tazobactam against Gram-Negative Isolates collected from ICU Patients with Lower Respiratory Tract Infections in Seven Asian Countries - SMART 2017-2019

OBJECTIVES

Antimicrobial resistance is one of the top 10 global public health threats. Especially high rates of resistance have been reported for isolates from ICU patients, requiring expanded treatment options in this setting. We evaluated the activity of ceftolozane/tazobactam and comparators against gram-negative isolates collected from patients with lower respiratory tract infections (LRTI) in ICUs in seven Asian countries.

METHODS

In 2017-2019, up to 100 consecutive aerobic gram-negative LRTI isolates were collected per year at each of 37 hospitals. MICs were determined using the Clinical and Laboratory Standards Institute reference broth microdilution method.

RESULTS

Overall, ceftolozane/tazobactam was active against 72% of 1408 Enterobacterales and 86% of 761 P. aeruginosa isolates. Susceptibility to the non-carbapenem β-lactam comparators, including piperacillin/tazobactam, was 52-67% among Enterobacterales isolates, and the activity of all β-lactam comparators, including meropenem, was 57-70% among P. aeruginosa. Ceftolozane/tazobactam maintained activity against 61% of meropenem-nonsusceptible and 64% of piperacillin/tazobactam-nonsusceptible P. aeruginosa isolates. At the country-level, ceftolozane/tazobactam activity ranged from >90% against Enterobacterales isolates from Hong Kong and South Korea to <64% in Thailand and Vietnam, and from >90% against P. aeruginosa from South Korea, Malaysia, Philippines, and Taiwan to <75% in Thailand and Vietnam. Correspondingly, the proportions of carbapenemase-positive isolates among Enterobacterales and P. aeruginosa isolates were highest in Thailand and Vietnam.

CONCLUSIONS

Ceftolozane/tazobactam provides a potential treatment option for ICU patients in Asia, which is especially important considering the reduced activity of commonly used β-lactams against the studied ICU isolates. Knowledge of local resistance patterns should inform empiric therapy decision-making.

First Detection of Klebsiella pneumoniae Isolate Co-Harboring Fosfomycin Resistance Gene fosA3 and blactx-m Among Gram Negative Urine Isolates in a Turkish Hospital

The most common gram-negative pathogens in urinary tract infections are Escherichia coli and Klebsiella pneumoniae. Therapy that is often empirical relies on local antibiotic resistance data, hence monitorization of antimicrobial resistance periodically in each hospital is a requirement. In this study, antibiotic susceptibility profiles of consecutive urinary isolates (E. coli [n = 235] and K. pneumoniae [n = 56]) of adult patients collected between February 2018 and February 2019 from inpatients in Hacettepe University Hospital were assessed. Isolates resistant to fosfomycin (minimum inhibitory concentration >32 mg/L) were further investigated for the presence of fosA, fosA3, and fosC2. Fosfomycin susceptibility was determined by agar dilution method. Broth microdilution method was performed for amikacin, gentamicin, ceftazidime, ceftriaxone, meropenem, ciprofloxacin, tigecycline, trimethoprim/sulfamethoxazole (TMP/SMX), colistin, and piperacillin/tazobactam (PIP/TAZ). PCR method was employed to investigate fosA, fosA3, fosC2, and bla_CTX-M. Existence of fosA3 gene was confirmed by sequencing. Resistance rates to amikacin, gentamicin, ceftazidime, ceftriaxone, meropenem, ciprofloxacin, tigecycline, TMP/SMX, colistin, and PIP/TAZ were 2.7%, 18.5%, 25.4%, 33.0%, 3.4%, 45.4%, 2.4%, 43.6%, 6.2%, and 23.7%, respectively. Sixteen isolates (5.5%) were resistant to fosfomycin. Resistance was most frequently observed in K. pneumoniae (n = 9). fosA3 gene was detected in one fosfomycin-resistant K. pneumoniae isolate. This isolate also carried bla_CTX-M. fosC2 and fosA genes could not be detected in any of the isolates. In this study, we report for the first time the existence of fosA3 in Turkey and its association with the bla_CTX-M gene. As a result of increasing bla_CTX-M producing Enterobacterales isolates globally, increase in fosfomycin resistance may be expected in near future.

Incidence of Healthcare-Associated Infections (HAIs) and the adherence to the HAIs' prevention strategies in a military hospital in Alkharj

Background

Healthcare-associated infections (HAI) are considered one of the most common adverse events in health care service provision. In order to prevent the occurrence of HAIs, it is important to implement several prevention strategies.

Objectives

This study aims to determine the incidence of healthcare-associated infections in a military hospital in Alkharj and the adherence to the HAIs' prevention strategies.

Methods

This study included exporting data for all infected cases confirmed by the infection disease specialists in 2019. The data were collected from the reports that were written by infection control unit and infectious disease department.

Results

The rate of healthcare associated infections (HAIs) in 2019 was 0.43% of total patient admissions. The rate of central line associated bloodstream infections in 2019 was 1.15 per 1000 central line days. The rate of catheter associated urinary tract infections in 2019 was 1.00 per 1000 catheter days. The rate of ventilator associated pneumonia in 2019 was 2.11 per 1000 ventilator days and the rate of surgical site infections in 2019 was 0.41 %.

Conclusion

The rate of overall healthcare-associated infections (HAI) was low. The compliance rate of health care workers to preventive measures that control HAIs was generally high but there was a need for more awareness particularly regarding personal protective equipment and hand hygiene. So it is important to attend more awareness activities and workshops particularly regarding personal protective equipment and hand hygiene. Furthermore, infection control unit and infectious disease department in the hospital should support the robust HAI prevention programs.

Uropathogens Antimicrobial Sensitivity and Resistance Pattern From Outpatients in Balochistan, Pakistan

Objective To determine the pattern of microbes responsible for urinary tract infections and their susceptibility to different antibiotics. Method This is a cross-sectional study conducted at Quetta, Pakistan. The urine samples of 400 patients were collected and sent for culture and sensitivity analysis. The results were recorded on an excel datasheet. Descriptive statistics were used to describe the data. Results Out of 400 urine samples, 266 samples were culture positive for microorganisms. The most common organism on analysis was Escherichia coli 123/266 (46.24%) followed by Staphylococcus saprophyticus 59/266 (22.18%) and Klebsiella pneumonia 49/266 (18.42%). Gram-negative microorganisms were most susceptible to fosfomycin, cefoperazone/sulbactam, and meropenem. Gram-positive microorganisms were most susceptible to fosfomycin, cefoperazone/sulbactam, meropenem, and amoxicillin/clavulanate. High rates of resistance in E. coli were observed to most commonly prescribed broad-spectrum antibiotics; ceftriaxone (64.35%), cefotaxime (76.54%), ceftazidime (49.43%), cefepime (53.44%), levofloxacin (71.26%), and amoxicillin/clavulanate (70.31%). E. coli was the major multidrug-resistant organism. Conclusion High rates of antibiotic resistance and multi-drug resistance were revealed in this study due to the widespread and injudicious use of broad-spectrum antibiotics. Thus, it is highly recommended to regulate the pharmacies. Physicians should judiciously prescribe antibiotics and practice the culture and sensitivity of urine samples rather than blind prescription. Continued surveillance on uropathogens prevalence and resistance, new and next-generation antibiotics, and rapid diagnostic tests to differentiate viral from bacterial infections is the need of time.

Major bacterial isolate and antibiotic resistance from routine clinical samples in Southern Ethiopia

Currently, antibiotic-resistant bacterial infections are a challenge for the health care system. Although physicians demand timely drug resistance data to guide empirical treatment, local data is rather scarce. Hence, this study performed a retrospective analysis of microbiological findings at the Hawassa public hospital. Secondary data were retrieved to assess the prevalence and level of drug resistance for the most common bacterial isolates from clinical samples processed at Hawassa University Comprehensive Specialized Hospital. Out of 1085 clinical samples processed in the microbiology laboratory, the prevalence of bacterial infection was 32.6%. Bacterial bloodstream infection was higher in children than in adults (OR, 4; 95% CI 1.8-14.6; p = 0.005). E. coli and K. pneumoniae were the commonest bacterial isolate both in children (36.8%, 26.3%) and in adults (33.3%, 26.7%) from the urine sample while, the leading bacteria identified from the CSF sample was P. aeruginosa, 37% in children and 43% in adult. In this study, all identified bacterial isolates were multi-drug resistant (MDR) ranging from 50 to 91%. The highest proportion of MDR was S. aureus 91.1 followed by K. pneumoniae 87.6%. Since the nationwide investigation of bacterial isolate, and drug resistance is rare in Ethiopia, a report from such type of local surveillance is highly useful to guide empirical therapy by providing awareness on the level resistance of isolates.

Treatment of patients with serious infections due to carbapenem-resistant Acinetobacter baumannii: How viable are the current options?

This review critically appraises the published microbiologic and clinical data on the treatment of patients with carbapenem-resistant Acinetobacter baumannii infections. Despite being recognized as an urgent threat pathogen by the CDC and WHO, optimal treatment of patients with serious CRAB infections remains ill-defined. Few commercially available agents exhibit reliable in vitro activity against CRAB. Historically, polymyxins have been the most active agents in vitro, though interpretations of susceptibility data are difficult given issues surrounding MIC testing methodologies and lack of correlation between MICs and clinical outcomes. Most available preclinical and clinical data involve use of polymyxins, tetracyclines, and sulbactam, alone and in combination. As the number of viable treatment options is limited, combination therapy with a polymyxin is often used for patients with CRAB infections, despite the significant risk of nephrotoxicity. However, no treatment regimen has been found to reduce mortality, which exceeds 40% across most studies, or substantially improve clinical response. While some newer agents, such as eravacycline and cefiderocol, have demonstrated in vitro activity, clinical efficacy has not been fully established. New agents with clinically relevant activity against CRAB isolates and favorable toxicity profiles are sorely needed.

Current antibiotic resistance patterns of rare uropathogens: survey from Central European Urology Department 2011-2019

BACKGROUND

While the resistance rates of commonly detected uropathogens are well described, those of less frequent Gram-negative uropathogenic bacteria have seldom been reported. The aim of this study was to examine the resistance rates of less frequent uropathogenic Gram-negatives in a population of patients treated in a Department of Urology of a tertiary referral centre in Central Europe over a period of 9 years.

METHODS

Data on all positive urine samples from urological in- and out-patients were extracted form the Department of Clinical Microbiology database from 2011 to 2019. Numbers of susceptible and resistant isolates per year were calculated for these uropathogens: Acinetobacter spp. (n = 74), Citrobacter spp. (n = 60), Enterobacter spp. (n = 250), Morganella morganii (n = 194), Providencia spp. (n = 53), Serratia spp. (n = 82) and Stenotrophomonas maltophilia (n = 27). Antimicrobial agents selected for the survey included: ampicillin, amoxicillin/clavulanic acid, piperacillin/tazobactam; cefuroxime, cefotaxime, ceftazidime and cefepime; ciprofloxacin and ofloxacin; gentamicin and amikacin; ertapenem, meropenem and imipenem; trimethoprim-sulfamethoxazole (co-trimoxazole), nitrofurantoin and colistin.

RESULTS

Penicillin derivatives have generally poor effect except piperacillin/tazobactam. Cefuroxime is not efficient unlike cefotaxime (except against Acinetobacter spp. and S. maltophilia). Susceptibility to fluoroquinolones is limited. Amikacin is somewhat more efficient than gentamicine but susceptibilities for both safely exceed 80%. Nitrofurantoin shows virtually no efficiency. Cotrimoxazole acts well against Citrobacter spp., Serratia spp. and it is the treatment of choice for S. maltophilia UTIs. Among carbapenems, ertapenem was less efficient than meropenem and imipenem except for S. maltophilia whose isolates were mostly not suceptible to any carbapenems.

CONCLUSIONS

Uropathogenic microorganisms covered in this report are noteworthy for their frequently multi-drug resistant phenotypes. Knowledge of resistance patterns helps clinicians choose the right empirical antibiotic treatment when the taxonomical assignment of the isolate is known but sensitivity results are pending.

Imipenem/cilastatin/relebactam: A new carbapenem β-lactamase inhibitor combination

PURPOSE

The pharmacology, pharmacokinetics, pharmacodynamics, antimicrobial activity, efficacy, safety, and current regulatory status of imipenem/cilastatin/relebactam are reviewed.

SUMMARY

Imipenem/cilastatin/relebactam is a newly approved anti-infective combination of a well-established β-lactam and a new β-lactamase inhibitor for the treatment of complicated urinary tract infections (cUTIs), including pyelonephritis, and complicated intra-abdominal infections (cIAIs) caused by susceptible gram-negative bacteria in patients 18 years of age or older with limited or no alternative treatment options. The antibiotic is also indicated for the treatment of hospital-acquired bacterial pneumonia (HABP) and ventilator-associated bacterial pneumonia (VABP). The antibiotic is active in vitro against a wide range of pathogens, including multidrug-resistant (MDR) Pseudomonas aeruginosa and carbapenem-resistant Enterobacterales (CRE) such as Klebsiella pneumoniae carbapenemase. The addition of relebactam does not restore the activity of imipenem against metallo-β-lactamase (MBL)-producing Enterobacterales and carbapenem-resistant Acinetobacter baumannii. Two phase 3 clinical trials of imipenem/cilastatin/relebactam were conducted. In the RESTORE-IMI 1 trial, the efficacy and safety of imipenem/cilastatin/relebactam was found to be comparable to that of imipenem/cilastatin plus colistin for the treatment of infections caused by imipenem-nonsusceptible gram-negative bacteria in patients with HABP/VABP, cUTIs, and cIAIs, with a significantly lower incidence of nephrotoxicity reported with the new antibiotic. The RESTORE-IMI 2 trial demonstrated the noninferiority of imipenem/cilastatin/relebactam to piperacillin/tazobactam for the treatment of HABP/VABP. Commonly reported adverse events in clinical trials included anemia, elevated liver enzymes, electrolyte imbalances, nausea, vomiting, diarrhea, headache, fever, phlebitis and/or infusion-site reactions, and hypertension.

CONCLUSION

Imipenem/cilastatin/relebactam is a new β-lactam/β-lactamase inhibitor combination with activity against MDR gram-negative bacteria, including many CRE but excluding MBL-producing Enterobacterales and carbapenem-resistant Acinetobacter baumannii. It is approved for the treatment of cUTIs, cIAIs, and HABP/VABP.

Carbonic anhydrase inhibition, antioxidant activity against alveolar epithelial cells and antibacterial effect against Klebsiella pneumoniae enabled by synthesized silica nanoparticles through laser ablation technique

Silica (SiO₂) nanoparticles (NPs) were synthesized by laser ablation method and were characterized by TEM and DLS techniques. Afterwards, their inhibition activity against carbonic anhydrase (CA) isoforms (CA I and CA II) was explored by experimental and theoretical analysis. Also, the protective effect of SiO₂ NPs against H₂O₂-induced oxidative stress in alveolar epithelial cells (A549) were assessed by measurement of MTT, ROS level, CAT and SOD activity and GSH content. Finally, the NPs were screened for their antimicrobial activity using the MICs method against the Klebsiella pneumoniae. The result showed that the synthesized NPs have a size of around 40 nm. The inhibition activity by comparing IC50 values with acetazolamide as a positive control revealed that SiO₂ NPs in comparison with acetazolamide served as potent inhibitors against CA isoforms which was also confirmed by docking studies. The cellular assays indicated that the SiO₂ NPs with a concentration of 20 μg/mL stimulated a significant antioxidant activity against H₂O₂-induced oxidative cell damage through activation of CAT and SOD, an increase in the GSH content and reducing the level of ROS. The synthesize NPs also showed a good inhibition effect against Klebsiella pneumoniae as compared to Sulfamethoxazole as a positive control. In conclusion, this data may provide some useful information on the development of some platforms for pneumonia treatment and management.

Antibiotic Resistance Mechanisms and Their Transmission in Acinetobacter baumannii

The discovery of penicillin over 90 years ago and its subsequent uptake by healthcare systems around the world revolutionised global health. It marked the beginning of a golden age in antibiotic discovery with new antibiotics readily discovered from natural sources and refined into therapies that saved millions of lives. Towards the end of the last century, the rate of discovery slowed to a near standstill. The lack of discovery is compounded by the rapid emergence and spread of bacterial pathogens that exhibit resistance to multiple antibiotic therapies and threaten the sustainability of global healthcare systems. Acinetobacter baumannii is an opportunistic pathogen whose prevalence and impact has grown significantly over the last 20 years. It is recognised as a barometer of the antibiotic resistance crisis due to the diverse array of mechanisms by which it can become resistant.

Analogs of nitrofuran antibiotics are potent GroEL/ES inhibitor pro-drugs

In two previous studies, we identified compound 1 as a moderate GroEL/ES inhibitor with weak to moderate antibacterial activity against Gram-positive and Gram-negative bacteria including Bacillus subtilis, methicillin-resistant Staphylococcus aureus, Klebsiella pneumonia, Acinetobacter baumannii, and SM101 Escherichia coli (which has a compromised lipopolysaccharide biosynthetic pathway making bacteria more permeable to drugs). Extending from those studies, we developed two series of analogs with key substructures resembling those of known antibacterials, nitroxoline (hydroxyquinoline moiety) and nifuroxazide/nitrofurantoin (bis-cyclic-N-acylhydrazone scaffolds). Through biochemical and cell-based assays, we identified potent GroEL/ES inhibitors that selectively blocked E. faecium, S. aureus, and E. coli proliferation with low cytotoxicity to human colon and intestine cells in vitro. Initially, only the hydroxyquinoline-bearing analogs were found to be potent inhibitors in our GroEL/ES-mediated substrate refolding assays; however, subsequent testing in the presence of an E. coli nitroreductase (NfsB) in situ indicated that metabolites of the nitrofuran-bearing analogs were potent GroEL/ES inhibitor pro-drugs. Consequently, this study has identified a new target of nitrofuran-containing drugs, and is the first reported instance of such a unique class of GroEL/ES chaperonin inhibitors. The intriguing results presented herein provide impetus for expanded studies to validate inhibitor mechanisms and optimize this antibacterial class using the respective GroEL/ES chaperonin systems and nitroreductases from E. coli and the ESKAPE bacteria.

Current Antibiotic Resistance Trends of Uropathogens in Central Europe: Survey from a Tertiary Hospital Urology Department 2011-2019

Monitoring of pathogen resistance profiles is necessary to guide empirical antibiotic therapy before culture and sensitivity results become available. The aim of this study was to describe current antibiotic resistance patterns of five most frequent causative uropathogens in a Department of Urology of a tertiary referral centre in Central Europe over a period of nine years. The Hospital Department of Clinical Microbiology database was used to extract data on all positive urine samples from inpatients in the Department of Urology between 2011 and 2019. Numbers of susceptible and resistant isolates per year were calculated for five most frequent uropathogens: Escherichia coli, Enterococcus spp., Klebsiella spp., Pseudomonas aeruginosa, and Proteus spp. Antimicrobial agents selected for the survey included: ampicillin, amoxicillin/clavulanic acid, piperacillin/tazobactam; cefuroxime, cefotaxime, ceftazidime and cefepime; ciprofloxacin and ofloxacin; gentamicin and amikacin; ertapenem, meropenem and imipenem; trimethoprim-sulfamethoxazole (co-trimoxazole), nitrofurantoin, colistin, and vancomycin. High resistance rates of Gram-negative uropathogens were demonstrated to most common antimicrobials, with statistically significant increasing or decreasing trends in some cases. No carbapenem-resistant Enterobacteriaceae were isolated. Vancomycin-resistant Enterococcus spp. strains were rare in our population.

Multidrug resistant and extensively drug resistant Acinetobacter baumannii hospital infection associated with high mortality: a retrospective study in the pediatric intensive care unit

Background

Multidrug resistant (MDR) and extensively drug resistant (XDR) Acinetobacter baumannii presents challenges for clinical treatment and causes high mortality in children. We aimed to assess the risk factors and overall mortality for MDR/XDR Acinetobacter baumannii infected pediatric patients.

Methods

This retrospective study included 102 pediatric patients who developed MDR/XDR Acinetobacter baumannii infection in the pediatric intensive care unit (PICU) of Shanghai Children’s Hospital in China from December 2014 to May 2018.

Acinetobacter baumannii clinical isolates were recovered from different specimens including blood, sputum, bronchoalveolar lavage fluid, cerebrospinal fluid, ascites, hydrothorax, and urine. Antibiotic susceptibility test was determined according to the Clinical and Laboratory Standards Institute interpretive criteria. Clinical and biological data were obtained from the patients’ medical records.

Results

102 patients with Acinetobacter baumannii infection were enrolled. The median age was 36 (9.6, 98.8) months, and there were 63 male in the case group. The overall mortality rate was 29.4%, while the Acinetobacter baumannii-associated mortality rate was 16.7% (17/102, 12 bloodstream infections, 4 meningitis and 1 intra-abdominal infection). Bloodstream infections occurred in 28 patients (27.5%), and 10 patients (9.8%) among them had central line-associated bloodstream infections (6 central venous catheters, 2 PICCs, 1 venous infusion port and 1 arterial catheter). Cerebrospinal fluid (CSF) cultures were positive in 4(3.9%) patients. 14(13.7%) patients got positive cultures in ascites and hydrothorax. Lower respiratory isolates (56/102) accounted for 54.9% of all patients. Non-survival patients appeared to have a lower NK cell activity (6.2% ± 3.61% vs. 9.15% ± 6.21%, P = 0.029), higher CD4+ T cell ratio (39.67% ± 12.18% vs. 32.66% ± 11.44%, P = 0.039),and a higher serum level of interlukin-8 (IL-8, 15.25 (1.62, 47.22)pg/mL vs. 0.1 (0.1, 22.99)pg/mL, P = 0.01) when Acinetobacter baumannii infection developed. Multivariate logistic analysis indicated that high serum level of Cr (RR, 0.934, 95%CI, 0.890–0.981; P = 0.007) and high BUN/ALB level (RR, 107.893, 95%CI, 1.425–870.574; p = 0.005) were associated with high risk of mortality in MDR/XDR Acinetobacter baumannii infected patients.

Conclusion

MDR/XDR Acinetobacter baumannii infection is a serious concern in pediatric patients with high mortality. Bloodstream and central nervous system infection accounted for high risk of death. Acute kidney injury is associated with high risk of mortality.

Epidemiology, Treatment, and Prevention of Nosocomial Bacterial Pneumonia

Septicaemia likely results in high case-fatality rates in the present multidrug-resistant (MDR) era. Amongst them are hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), two frequent fatal septicaemic entities amongst hospitalised patients. We reviewed the PubMed database to identify the common organisms implicated in HAP/VAP, to explore the respective risk factors, and to find the appropriate antibiotic choice. Apart from methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, extended-spectrum β-lactamase-producing Enterobacteriaceae spp., MDR or extensively drug-resistant (XDR)-Acinetobacter baumannii complex spp., followed by Stenotrophomonas maltophilia, Chryseobacterium indologenes, and Elizabethkingia meningoseptica are ranked as the top Gram-negative bacteria (GNB) implicated in HAP/VAP. Carbapenem-resistant Enterobacteriaceae notably emerged as an important concern in HAP/VAP. The above-mentioned pathogens have respective risk factors involved in their acquisition. In the present XDR era, tigecycline, colistin, and ceftazidime-avibactam are antibiotics effective against the Klebsiella pneumoniae carbapenemase and oxacillinase producers amongst the Enterobacteriaceae isolates implicated in HAP/VAP. Antibiotic combination regimens are recommended in the treatment of MDR/XDR-P. aeruginosa or A. baumannii complex isolates. Some special patient populations need prolonged courses (>7-day) and/or a combination regimen of antibiotic therapy. Implementation of an antibiotic stewardship policy and the measures recommended by the United States (US) Institute for Healthcare were shown to decrease the incidence rates of HAP/VAP substantially.

Activity of ceftolozane-tazobactam against Gram-negative pathogens isolated from lower respiratory tract infections in the Asia-Pacific region: SMART 2015-2016

The aim of this study was to investigate the susceptibility of respiratory Gram-negative bacteria to ceftolozane/tazobactam and other antibiotics in the Asia-Pacific region during 2015-2016. MICs were determined using the CLSI standard broth microdilution method and interpreted accordingly. Pseudomonas aeruginosa (1574 isolates), Klebsiella pneumoniae (1226), Acinetobacter baumannii (627) and Escherichia coli (476) accounted for 73.1% of 5342 Gram-negative respiratory pathogens. Susceptibility to ceftolozane/tazobactam of individual Enterobacteriaceae was >80%, except for Enterobacter cloacae (76.6%). Ceftolozane/tazobactam inhibited 81.9% of K. pneumoniae and 91.9% of E. coli, with respective MIC₅₀/MIC₉₀ values of 0.5/>32 and 0.25/2 mg/L. For carbapenem-susceptible, ESBL-producing K. pneumoniae and E. coli, susceptibility was 65.5% and 93.3%, respectively, and respective MIC₅₀/MIC₉₀ values were 2/>32 and 0.5/2 mg/L. Bla_{CTX-M-1 group} was most prevalent in selected ESBL-producing K. pneumoniae (40 of 54 isolates) and E. coli (15 of 22 isolates), with ceftolozane/tazobactam susceptibility rates of 50% and 80%, respectively. Bla_SHV-ESBL was the second most prevalent, and ceftolozane/tazobactam inhibited 20% of 20 K. pneumoniae isolates with bla_SHV-ESBL. The only effective antibiotics for carbapenem-non-susceptible K. pneumoniae (111 isolates) and E. coli (24 isolates) were amikacin and colistin. Ceftolozane/tazobactam was effective against almost all tested P. aeruginosa and carbapenem-non-susceptible strains, with susceptibility of 92.3% and 72.8%, respectively; the respective MIC₅₀/MIC₉₀ values were 1/4 and 2/>32 mg/L. The high susceptibility of ceftolozane/tazobactam remained in different age groups, patient locations, recovery times and countries, except Vietnam. In conclusion, ceftolozane/tazobactam was effective against most respiratory Gram-negative pathogens in the Asia-Pacific region; however, the emergence of carbapenem resistance mandates ongoing surveillance.

Non-natural 2H-azirine-2-carboxylic acids: an expedient synthesis and antimicrobial activity

Non-natural 2H-azirine-2-carboxylic acids were obtained in high yields by FeCl2-catalyzed isomerization of 5-chloroisoxazoles to azirine-2-carbonyl chlorides followed by their hydrolysis. The 3-aryl- and 3-heteroaryl-substituted acids are stable during prolonged storage, exhibit antibacterial activity against ESKAPE pathogens and show a low level of cytotoxicity.

Economic burden of antibiotic resistance in ESKAPE organisms: a systematic review

Background

Antibiotic resistance (ABR) is one of the biggest threats to global health. Infections by ESKAPE (Enterococcus, S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa, and E. coli) organisms are the leading cause of healthcare-acquired infections worldwide. ABR in ESKAPE organisms is usually associated with significant higher morbidity, mortality, as well as economic burden. Directing attention towards the ESKAPE organisms can help us to better combat the wide challenge of ABR, especially multi-drug resistance (MDR).

Objective

This study aims to systematically review and evaluate the evidence of the economic consequences of ABR or MDR ESKAPE organisms compared with susceptible cases or control patients without infection/colonization in order to determine the impact of ABR on economic burden.

Methods

Both English-language databases and Chinese-language databases up to 16 January, 2019 were searched to identify relevant studies assessing the economic burden of ABR. Studies reported hospital costs (charges) or antibiotic cost during the entire hospitalization and during the period before/after culture among patients with ABR or MDR ESKAPE organisms were included. The costs were converted into 2015 United States Dollars. Disagreements were resolved by a third reviewer.

Results

Of 13,693 studies identified, 83 eligible studies were included in our review. The most studied organism was S. aureus, followed by Enterococcus, A. baumannii, E. coli, E. coli or/and K. pneumoniae, P. aeruginosa, and K. pneumoniae. There were 71 studies on total hospital cost or charge, 12 on antibiotic cost, 11 on hospital cost or charge after culture, 4 on ICU cost, 2 on hospital cost or charge before culture, and 2 on total direct and indirect cost. In general, ABR or MDR ESKAPE organisms are significantly associated with higher economic burden than those with susceptible organisms or those without infection or colonization. Nonetheless, there were no differences in a few studies between the two groups on total hospital cost or charge (16 studies), antibiotic cost (one study), hospital cost before culture (one study), hospital cost after culture (one study). Even, one reported that costs associated with MSSA infection were higher than the costs for similar MRSA cases.

Conclusions

ABR in ESKAPE organisms is not always, but usually, associated with significantly higher economic burden. The results without significant differences may lack statistical power to detect a significant association. In addition, study design which controls for severity of illness and same empirical antibiotic therapy in the two groups would be expected to bias the study towards a similar, even negative result. The review also highlights key areas where further research is needed.

Antimicrobial susceptibility changes of Escherichia coli and Klebsiella pneumoniae intra-abdominal infection isolate-derived pathogens from Chinese intra-abdominal infections from 2011 to 2015

Background

To explore the susceptibility trends of antimicrobials and resistance increase to antibiotics of Enterobacteriaceae isolated from patients in China with intra-abdominal infections (IAI) from 2011 to 2015.

Methods

MIC₉₀ and MIC₅₀ values of 12 commonly used antibiotics from Escherichia coli and Klebsiella pneumoniae isolated from IAI samples were determined.

Results

A total of 8,477 Gram-negative bacterial pathogens were collected from 21 medical centers in China. The majority of IAI isolate-derived pathogens were E. coli (3,854, 45.5%) and K. pneumoniae (1,670, 19.7%) of which 1,990 (23.5%) were consecutively collected from community acquired (CA) and 6,186 (73.0%) from hospital acquired (HA) IAIs. The drugs with the highest efficacy against E. coli and K. pneumoniae isolates derived from IAI samples were imipenem, ertapenem, amikacin and piperacillin-tazobactam. MIC₉₀ values for piperacillin-tazobactam were 64 µg/mL in 2015 with fluctuations from 16–64 µg/mL through the years for E. coli, but were stable at ≥64 µg/mL from 2011 to 2015 for K. pneumoniae isolates. Susceptibilities to ertapenem, imipenem and amikacin were high for E. coli isolates throughout the study, but K. pneumoniae isolated from abscesses, colon and peritoneal fluid collected from medical and surgical ICUs showed an increasing trend of carbapenem resistance in 2015.

Conclusion

In 2015 there was a trend of enhanced carbapenem resistance, particularly for K. pneumoniae isolated from IAI samples obtained from patients in ICUs.

In vitro studies evaluating the activity of imipenem in combination with relebactam against Pseudomonas aeruginosa

BACKGROUND

The prevalence of antibiotic resistance is increasing, and multidrug-resistant Pseudomonas aeruginosa has been identified as a serious threat to human health. The production of β-lactamase is a key mechanism contributing to imipenem resistance in P. aeruginosa. Relebactam is a novel β-lactamase inhibitor, active against class A and C β-lactamases, that has been shown to restore imipenem susceptibility. In a series of studies, we assessed the interaction of relebactam with key mechanisms involved in carbapenem resistance in P. aeruginosa and to what extent relebactam might overcome imipenem non-susceptibility.

RESULTS

Relebactam demonstrated no intrinsic antibacterial activity against P. aeruginosa, had no inoculum effect, and was not subject to efflux. Enzymology studies showed relebactam is a potent (overall inhibition constant: 27 nM), practically irreversible inhibitor of P. aeruginosa AmpC. Among P. aeruginosa clinical isolates from the SMART global surveillance program (2009, n = 993; 2011, n = 1702; 2015, n = 5953; 2016, n = 6165), imipenem susceptibility rates were 68.4% in 2009, 67.4% in 2011, 70.4% in 2015, and 67.3% in 2016. With the addition of 4 μg/mL relebactam, imipenem susceptibility rates increased to 87.6, 86.0, 91.7, and 89.8%, respectively. When all imipenem-non-susceptible isolates were pooled, the addition of 4 μg/mL relebactam reduced the mode imipenem minimum inhibitory concentration (MIC) 8-fold (from 16 μg/mL to 2 μg/mL) among all imipenem-non-susceptible isolates. Of 3747 imipenem-non-susceptible isolates that underwent molecular profiling, 1200 (32%) remained non-susceptible to the combination imipenem/relebactam (IMI/REL); 42% of these encoded class B metallo-β-lactamases, 11% encoded a class A GES enzyme, and no class D enzymes were detected. No relationship was observed between alleles of the chromosomally-encoded P. aeruginosa AmpC and IMI/REL MIC.

CONCLUSIONS

IMI/REL exhibited potential in the treatment of carbapenem-resistant P. aeruginosa infections, with the exception of isolates encoding class B, some GES alleles, and class D carbapenemases.

Attachment of a 5-nitrofuroyl moiety to spirocyclic piperidines produces non-toxic nitrofurans that are efficacious in vitro against multidrug-resistant Mycobacterium tuberculosis

A selectively antimycobacterial compound belonging to the nitrofuran class of antimicrobials has been developed via conjugation of the nitrofuran moiety to a series of spirocyclic piperidines through an amide linkage. It proved to have comparable activity against drug-sensitive (H37Rv) strain as well as multidrug-resistant, patient-derived strains of Mycobacterium tuberculosis. The compound is druglike, showed no appreciable cytotoxicity toward human retinal pigment epithelial cell line ARPE-19 in concentrations up to 100 μM and displayed low toxicity when evaluated in mice.

Evaluation of Aminoglycoside and Carbapenem Resistance in a Collection of Drug-Resistant Pseudomonas aeruginosa Clinical Isolates

Pseudomonas aeruginosa, a Gram-negative bacterium, is a member of the ESKAPE pathogens and one of the leading causes of healthcare-associated infections worldwide. Aminoglycosides (AGs) are recognized for their efficacy against P. aeruginosa. The most common resistance mechanism against AGs is the acquisition of AG-modifying enzymes (AMEs) by the bacteria, including AG N-acetyltransferases (AACs), AG O-phosphotransferases (APHs), and AG O-nucleotidyltransferases (ANTs). In this study, we obtained 122 multidrug-resistant P. aeruginosa clinical isolates and evaluated the antibacterial effects of six AGs and two carbapenems alone against all clinical isolates, and in combination against eight selected strains. We further probed for four representatives of the most common AME genes [aac(6')-Ib, aac(3)-IV, ant(2")-Ia, and aph(3')-Ia] by polymerase chain reaction (PCR) and compared the AME patterns of these 122 clinical isolates to their antibiotic resistance profile. Among the diverse antibiotics resistance profile displayed by these clinical isolates, we found correlations between the resistance to various AGs as well as between the resistance to one AG and the resistance to carbapenems. PCR results revealed that the presence of aac(6')-Ib renders these isolates more resistant to a variety of antibiotics. The correlation between resistance to various AGs and carbapenems partially reflects the complex resistance strategies adapted in these pathogens and encourages the development of strategic treatment for each P. aeruginosa infection by considering the genetic information of each isolated bacteria.

Pharmacokinetics, Safety, and Tolerability of Single and Multiple Doses of Relebactam, a β-Lactamase Inhibitor, in Combination with Imipenem and Cilastatin in Healthy Participants

Relebactam is a novel class A and C β-lactamase inhibitor that is being developed in combination with imipenem-cilastatin for the treatment of serious infections with Gram-negative bacteria. Here we report on two phase 1 randomized, double-blind, placebo-controlled pharmacokinetics, safety, and tolerability studies of relebactam administered with or without imipenem-cilastatin to healthy participants: (i) a single-dose (25 to 1,150 mg) and multiple-dose (50 to 625 mg every 6 h [q6h] for 7 to 14 days) escalation study with men and (ii) a single-dose (125 mg) study with women and elderly individuals.

Relebactam is a novel class A and C β-lactamase inhibitor that is being developed in combination with imipenem-cilastatin for the treatment of serious infections with Gram-negative bacteria. Here we report on two phase 1 randomized, double-blind, placebo-controlled pharmacokinetics, safety, and tolerability studies of relebactam administered with or without imipenem-cilastatin to healthy participants: (i) a single-dose (25 to 1,150 mg) and multiple-dose (50 to 625 mg every 6 h [q6h] for 7 to 14 days) escalation study with men and (ii) a single-dose (125 mg) study with women and elderly individuals. Following single- or multiple-dose intravenous administration over 30 min, plasma relebactam concentrations declined biexponentially, with a terminal half-life (t_1/2) ranging from 1.35 to 1.85 h independently of the dose. Exposures increased in a dose-proportional manner across the dose range. No clinically significant differences in pharmacokinetics between men and women, or between adult and elderly participants, were observed. Urine pharmacokinetics demonstrated that urinary excretion is the major route of relebactam elimination. No drug-drug interaction between relebactam and imipenem-cilastatin was observed, and the observed t_1/2 values for relebactam, imipenem, and cilastatin were comparable, thus supporting coadministration. Relebactam administered alone or in combination with imipenem-cilastatin was well tolerated across the dose ranges studied. No serious adverse events or deaths were reported. The pharmacokinetic profile and favorable safety results supported q6h dosing of relebactam with imipenem-cilastatin in clinical treatment trials.

In vitro activity of tigecycline and comparators (2014-2016) among key WHO 'priority pathogens' and longitudinal assessment (2004-2016) of antimicrobial resistance: a report from the T.E.S.T. study

We report contemporary (2014-2016) Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) global data on activity of tigecycline and comparators against WHO 'priority pathogens', and global trends (2004-2016) in antimicrobial resistance. MICs were determined using CLSI broth microdilution methodology. Antimicrobial resistance was determined using CLSI breakpoints (FDA breakpoints for tigecycline). Data are reported for Africa, Asia, Europe, North America and South America. From 2014-2016, Africa, Asia and South America reported highest resistance rates among Acinetobacter baumannii; North America lowest (all antimicrobials tested). The tigecycline MIC₉₀ against A. baumannii was 2 mg/L in all regions except South America (1 mg/L). Among Enterobacteriaceae, meropenem resistance was low and tigecycline resistance was ≤1.3% in all regions (Escherichia coli, 0.0-0.3%; Klebsiella pneumoniae 0.0-1.3%; Enterobacter spp. 0.5-1.1%; Serratia marcescens 0.0-1.3%). Ceftriaxone resistance among E. coli ranged from 14.5% (North America) to 54.7% (Asia), and among K. pneumoniae from 9.1% (North America) to 54.0% (South America). North America reported highest rates of vancomycin-resistant Enterococcus faecium (64.6%); Europe lowest (17.7%). The tigecycline MIC₉₀ against methicillin-resistant Staphylococcus aureus (MRSA) ranged from 0.12 mg/L (Africa and North America) to 0.5 mg/L (Asia). From 2004-2016, carbapenem resistance increased among A. baumannii (all regions), reaching 92.3% in Africa and 85.7% in South America (2016). Rates of ceftriaxone-resistant E. coli increased in all regions except Asia. Ceftriaxone resistance in K. pneumoniae increased in Europe. Rates of vancomycin-resistant E. faecium and MRSA were highest in North America and South America (and Asia for MRSA); lowest in Europe.

Sulfonamido-2-arylbenzoxazole GroEL/ES Inhibitors as Potent Antibacterials against Methicillin-Resistant Staphylococcus aureus (MRSA)

Extending from a study we recently published examining the antitrypanosomal effects of a series of GroEL/ES inhibitors based on a pseudosymmetrical bis-sulfonamido-2-phenylbenzoxazole scaffold, here, we report the antibiotic effects of asymmetric analogs of this scaffold against a panel of bacteria known as the ESKAPE pathogens ( Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). While GroEL/ES inhibitors were largely ineffective against K. pneumoniae, A. baumannii, P. aeruginosa, and E. cloacae (Gram-negative bacteria), many analogs were potent inhibitors of E. faecium and S. aureus proliferation (Gram-positive bacteria, EC₅₀ values of the most potent analogs were in the 1-2 μM range). Furthermore, even though some compounds inhibit human HSP60/10 biochemical functions in vitro (IC₅₀ values in the 1-10 μM range), many of these exhibited moderate to low cytotoxicity to human liver and kidney cells (CC₅₀ values > 20 μM).

Pathogenic bacteria in abdominal cavity drainage of patients with intraabdominal infection and their drug resistance

AIM

To identify the pathogenic bacteria in abdominal cavity drainage of patients with intraabdominal infection and to analyze their drug resistance.

METHODS

From January 2015 to November 2017, 92 patients with intraperitoneal infection were treated by celiac drainage at our hospital. The bacterial culture and drug susceptibility results of peritoneal drainage fluid were statistically analyzed, and the differences in different bacterial populations and drug resistance were analyzed. Cox regression model was used to explore the independent risk factors affecting the prognosis of patients.

RESULTS

A total of 145 bacterial strains were cultured, including 46 Gram-positive and 97 Gram-negative strains. The top five pathogens were Escherichia coli (31.72%), Klebsiellosis pneumoniae (24.14%), Staphylococcus aureus (15.86%), Enterococcus (11.72%), and Pseudomonas aeruginosa (7.59%). Staphylococcus aureus and Enterococcus were two Gram-positive strains that had high resistance rates but were highly sensitive to vancomycin. Enterococci had high resistance rates to erythromycin, chloramphenicol, and levofloxacin than Staphylococcus aureus, which had a high resistance rate to ampicillin. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and other three kinds of G-bacteria had high resistance rates, but all of them had a high sensitivity to β-lactams/β-lactamase inhibitors, imipenem/Cistadine and amikacin; among them, extended spectrum beta lactamase (ESBL) producing strains and Pseudomonas aeruginosa had high resistance rates to ceftriaxone, ceftazidime, cefepime, and levofloxacin. Univariate Cox regression analysis showed that age, multidrug resistant organism (MDRO), nosocomial infection, ESBL positivity, and time from fever to culture were related to death in patients with intraabdominal infection. Multivariate Cox regression analysis showed that MDRO, ESBL positivity, and time from fever to culture were independent risk factors for death in patients with intraabdominal infection.

CONCLUSION

Main pathogens in peritoneal drainage fluid of patients with intraabdominal infection are Gram-negative bacteria, and the pathogens are highly resistant to commonly used antibiotics. MDRO, ESBL positivity, and time from fever to culture are independent risk factors for death from intraabdominal infection.

Antibiotic Hybrids: the Next Generation of Agents and Adjuvants against Gram-Negative Pathogens?

The global incidence of drug-resistant Gram-negative bacillary infections has been increasing, and there is a dire need to develop novel strategies to overcome this problem. Intrinsic resistance in Gram-negative bacteria, such as their protective outer membrane and constitutively overexpressed efflux pumps, is a major survival weapon that renders them refractory to current antibiotics. Several potential avenues to overcome this problem have been at the heart of antibiotic drug discovery in the past few decades. We review some of these strategies, with emphasis on antibiotic hybrids either as stand-alone antibacterial agents or as adjuvants that potentiate a primary antibiotic in Gram-negative bacteria. Antibiotic hybrid is defined in this review as a synthetic construct of two or more pharmacophores belonging to an established agent known to elicit a desired antimicrobial effect. The concepts, advances, and challenges of antibiotic hybrids are elaborated in this article. Moreover, we discuss several antibiotic hybrids that were or are in clinical evaluation. Mechanistic insights into how tobramycin-based antibiotic hybrids are able to potentiate legacy antibiotics in multidrug-resistant Gram-negative bacilli are also highlighted. Antibiotic hybrids indeed have a promising future as a therapeutic strategy to overcome drug resistance in Gram-negative pathogens and/or expand the usefulness of our current antibiotic arsenal.

Treatment of Infections Caused by Extended-Spectrum-Beta-Lactamase-, AmpC-, and Carbapenemase-Producing Enterobacteriaceae

Therapy of invasive infections due to multidrug-resistant Enterobacteriaceae (MDR-E) is challenging, and some of the few active drugs are not available in many countries. For extended-spectrum β-lactamase and AmpC producers, carbapenems are the drugs of choice, but alternatives are needed because the rate of carbapenem resistance is rising. Potential active drugs include classic and newer β-lactam-β-lactamase inhibitor combinations, cephamycins, temocillin, aminoglycosides, tigecycline, fosfomycin, and, rarely, fluoroquinolones or trimethoprim-sulfamethoxazole. These drugs might be considered in some specific situations. AmpC producers are resistant to cephamycins, but cefepime is an option. In the case of carbapenemase-producing Enterobacteriaceae (CPE), only some "second-line" drugs, such as polymyxins, tigecycline, aminoglycosides, and fosfomycin, may be active; double carbapenems can also be considered in specific situations. Combination therapy is associated with better outcomes for high-risk patients, such as those in septic shock or with pneumonia. Ceftazidime-avibactam was recently approved and is active against KPC and OXA-48 producers; the available experience is scarce but promising, although development of resistance is a concern. New drugs active against some CPE isolates are in different stages of development, including meropenem-vaborbactam, imipenem-relebactam, plazomicin, cefiderocol, eravacycline, and aztreonam-avibactam. Overall, therapy of MDR-E infection must be individualized according to the susceptibility profile, type, and severity of infection and the features of the patient.

In vitro and in vivo antimicrobial activity of TS2037, a novel aminoglycoside antibiotic

To overcome serious methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa infections, we synthesized TS2037, 5,4″-diepi-arbekacin, a novel aminoglycoside antibiotic, and evaluated its biological properties. TS2037 showed broad-range, as well as robust antibacterial activities against Gram-positive and Gram-negative bacteria. The MIC₅₀ and MIC₉₀ of TS2037 against clinical isolates of MRSA (n = 54) were both 0.25 µg/mL, and no resistant strain was observed. The MIC₅₀ and MIC₉₀ of TS2037 against clinical isolates of P. aeruginosa (n = 54) were 1 and 4 µg/mL, respectively. TS2037 and arbekacin, anti-MRSA aminoglycoside, were more stable against AAC(6')-APH(2″), aminoglycoside-6'-N-acetyltransferase and 2″-O-phosphotransferase, produced by resistant S. aureus than gentamicin. Therapeutic efficacies of TS2037 in the mouse models of systemic infection with MRSA were superior to those of arbekacin, vancomycin, and linezolid. The efficacy of TS2037 against systemic infection caused by P. aeruginosa producing AAC(6')-II was superior to those of arbekacin and amikacin. In the nephrotoxicity risk screening, the release of free N-acetyl-β-D-glucosaminidase from the kidney epithelial cell line after treatment with TS2037 at 2.5 and 5.0 μM were 2.0 and 2.1 (U/L), respectively, which were about two times higher than those of arbekacin. In conclusion, TS2037 exhibited the most potent antibacterial activity among aminoglycosides tested against both MRSA and P. aeruginosa in vitro and in vivo, although its nephrotoxicity risk remains to be improved.

Antimicrobial resistance in urine and skin isolates in Timor-Leste

OBJECTIVES

High rates of antimicrobial resistance (AMR) are seen throughout Southeast Asia. However, limited AMR data exist for Timor-Leste, which is situated on the south-eastern portion of the Malay Archipelago. The purpose of this study was to identify AMR in bacteria isolated from urine and skin swabs from patients in Dili, the capital of Timor-Leste.

METHODS

Urine and skin swabs were collected from symptomatic patients in Timor-Leste and were processed for bacterial culture. Isolates were processed in Australia using a VITEK^®2 system for bacterial identification and to determine antimicrobial susceptibility according to Clinical and Laboratory Standards Institute (CLSI) guidelines.

RESULTS

A total of 154 urine isolates and 57 skin isolates were analysed. Of the Enterobacteriaceae, 35% were resistant to ceftriaxone with an extended-spectrum β-lactamase (ESBL)-producing phenotype. Carbapenem resistance was not observed in any of the Gram-negative isolates. Of the Staphylococcus aureus isolates, 11% were of the community-associated methicillin-resistant S. aureus (CA-MRSA) phenotype.

CONCLUSIONS

A moderately high proportion of Gram-negative urine isolates in Timor-Leste demonstrate phenotypic ESBL production, and a relatively low proportion of S. aureus isolates were methicillin-resistant. Improved understanding of AMR rates in Timor-Leste can help guide antimicrobial prescribing and inform antimicrobial stewardship strategies.

Phenotypic and Molecular Characterization of Multidrug Resistant Klebsiella pneumoniae Isolated from Different Clinical Sources in Al-Najaf Province-Iraq

BACKGROUND AND OBJECTIVE

Burns infections and urinary tract infections are the most important prevalent diseases in Asian countries, such as Iraq. Klebsiella pneumoniae is one of the most important bacteria cause this type of infections especially in hospitals. Therefore, the aim of this study was to investigate the prevalence of multi-drug resistance K. pneumoniae and extended-spectrum beta-lactamases producing K. pneumoniae isolates from inpatients with urinary tract infection and burns infections in Al-Kufa hospital in Al-Najaf province, Iraq.

MATERIALS AND METHODS

A total of 285 clinical samples were collected from in-patients infected with urinary tract infection (141 urine samples) and burns infections (144 burns swabs). Fourteen different antibiotics were used by disc diffusion method and 13 antimicrobials resistance genes were used by PCR technique.

RESULTS

A total of 43 K. pneumoniae strains were isolated. The highest resistance rate was observed for amoxicillin 25 μg and amoxicillin+clavulanic acid 20+10 μg (97.67%) while the lowest resistance rate was observed for imipenem 10 μg (9.30%). The most common resistance associated-genes were blaSHV (86.04%) and at lower prevalence were IMP (9.30%).

CONCLUSION

Klebsiella pneumoniae strains isolated from burns infections were more virulent than those isolated from urinary tract infections.