Carbapenems Research Articles

Ceftazidime resistance in Pseudomonas aeruginosa is multigenic and complex.

Pseudomonas aeruginosa causes a wide range of severe infections. Ceftazidime, a cephalosporin, is a key antibiotic for treating infections but a significant proportion of isolates are ceftazidime-resistant. The aim of this research was to identify mutations that contribute to resistance, and to quantify the impacts of individual mutations and mutation combinations. Thirty-five mutants with reduced susceptibility to ceftazidime were evolved from two antibiotic-sensitive P. aeruginosa reference strains PAO1 and PA14. Mutations were identified by whole genome sequencing. The evolved mutants tolerated ceftazidime at concentrations between 4 and 1000 times that of the parental bacteria, with most mutants being ceftazidime resistant (minimum inhibitory concentration [MIC] ≥ 32 mg/L). Many mutants were also resistant to meropenem, a carbapenem antibiotic. Twenty-eight genes were mutated in multiple mutants, with dacB and mpl being the most frequently mutated. Mutations in six key genes were engineered into the genome of strain PAO1 individually and in combinations. A dacB mutation by itself increased the ceftazidime MIC by 16-fold although the mutant bacteria remained ceftazidime sensitive (MIC < 32 mg/L). Mutations in ampC, mexR, nalC or nalD increased the MIC by 2- to 4-fold. The MIC of a dacB mutant was increased when combined with a mutation in ampC, rendering the bacteria resistant, whereas other mutation combinations did not increase the MIC above those of single mutants. To determine the clinical relevance of mutations identified through experimental evolution, 173 ceftazidime-resistant and 166 sensitive clinical isolates were analysed for the presence of sequence variants that likely alter function of resistance-associated genes. dacB and ampC sequence variants occur most frequently in both resistant and sensitive clinical isolates. Our findings quantify the individual and combinatorial effects of mutations in different genes on ceftazidime susceptibility and demonstrate that the genetic basis of ceftazidime resistance is complex and multifactorial.

The C5α-Methyl-Substituted Carbapenem NA-1-157 Exhibits Potent Activity against Klebsiella spp. Isolates Producing OXA-48-Type Carbapenemases

The wide spread of carbapenem-hydrolyzing β-lactamases in Gram-negative bacteria has diminished the utility of the last-resort carbapenem antibiotics, significantly narrowing the available therapeutic options. In the Enterobacteriaceae family, which includes many important clinical pathogens such as Klebsiella pneumoniae and Escherichia coli, production of class D β-lactamases from the OXA-48-type family constitutes the major mechanism of resistance to carbapenems. To address the public health threat posed by these enzymes, novel, effective therapeutics are urgently needed. Here, we report evaluation of a novel, C5α-methyl-substituted carbapenem, NA-1-157, and show that its MICs against bacteria producing OXA-48-type enzymes were reduced by 4- to 32-fold when compared to meropenem. When combined with commercial carbapenems, the potency of NA-1-157 was further enhanced, resulting in target potentiation concentrations ranging from 0.125 to 2 μg/mL. Kinetic studies demonstrated that the compound is poorly hydrolyzed by OXA-48, with a catalytic efficiency 30- to 50-fold lower than those of imipenem and meropenem. Acylation of OXA-48 by NA-1-157 was severely impaired, with a rate 10,000- to 36,000-fold slower when compared to the commercial carbapenems. Docking, molecular dynamics, and structural studies demonstrated that the presence of the C5α-methyl group in NA-1-157 creates steric clashes within the active site, leading to differences in the position and the hydrogen-bonding pattern of the compound, which are incompatible with efficient acylation. This study demonstrates that NA-1-157 is a promising novel carbapenem for treatment of infections caused by OXA-48-producing bacterial pathogens.

Risk Factors and Prognosis of Delirium After Liver Transplantation

To analyze the incidence, the onset time, and the risk factors of delirium after liver transplantation (LT). The clinical data of 211 patients who underwent LT at Third Xiangya Hospital, Central South University between January 2019 and December 2021 were collected to investigate the incidence and the onset time of postoperative delirium. Univariate analysis and multivariate logistic regression analysis were conducted to analyze the risk factors of delirium and to analyze the effect of delirium on clinical outcomes. The incidence of delirium was 20.4% (43/211) and the median interval between LT and the onset of delirium was 19 hours. Univariate analysis showed that the preoperative Model for End-Stage Liver Disease (MELD) score≥22, preoperative length-of-stay≥7, liver cancer, preoperative hepatic encephalopathy, infections within 2 months before LT, preoperative lymphocyte value<0.5×10 9 L －1, massive amount of intraoperative red blood cell infusion, and carbapenem antibiotics use for 3 days or longer were associated with postoperative delirium. Multivariate logistic regression analysis showed that preoperative infections within 2 months before LT (odds ratio [ OR]=2.597, 95% confidence interval [ CI]: 1.135-5.944, P=0.024), preoperative MELD score≥22 ( OR=2.967, 95% CI: 1.104-7.975, P=0.031), and preoperative hepatic encephalopathy ( OR=4.700, 95% CI: 2.043-10.602, P<0.001) were independent risk factors for delirium after LT, while carbapenems antibiotics use for 3 days or longer ( OR=0.192, 95% CI: 0.083-0.441, P<0.001) was a protective factor for postoperative delirium among LT recipients. Regarding clinical outcomes, patients with delirium had longer postoperative ICU length-of-stays than those without delirium did ( P=0.025). There is a high incidence of postoperative delirium among patients who undergo LT and the onset time of delirium after LT is early. Risk factors include preoperative infections, high MELD score, and hepatic encephalopathy. On the other hand, the use of carbapenems can help prevent delirium.

Distribution and antibacterial susceptibility pattern of isolated bacteria from endotracheal aspirates among ventilator-assisted pneumonia patients in Indonesia.

An accurate and timely identification of causative microorganisms as well as determination of their antibiotic susceptibility patterns will help in the selection of proper antibiotics and prevention of their misuse in pneumonia patients. The aim of this study was to determine the distribution and antibiotic susceptibility pattern of bacteria isolated from endotracheal aspirates of ventilator-assisted pneumonia patients in Indonesia. A retrospective cross-sectional study was conducted at Dr. Zainoel Abidin Hospital, a provincial reference hospital in Banda Aceh, Indonesia, from January to December 2021. Ventilator-assisted pneumonia patients aged ≥17 years treated in the hospital were considered eligible. Antibiotic susceptibility was valuated using Kirby-Bauer disc-diffusion followed with VITEK 2 Compact. We included 57 patients of which 73.7% males and 26.3% aged 56-65 years (represent the majority group of the patients). Each patient reported at least one comorbidity and the average duration of receiving mechanical ventilation was 8.68 days, and more than half (59.7%) of the patients had a poor clinical outcome (died). A total 57 bacteria isolates (consisting nine species) were recovered; 68.5% Gram-negative and 31.5% Gram-positive bacteria. Among 57 patients, Acinetobacter baumannii was the most frequent isolated Gram-negative bacteria (19.3%), followed by Klebsiella pneumoniae (17.5%), Pseudomonas aeruginosa (15.8%), and Achromobacter denitrificans (12.3%). A. baumannii exhibited <70% sensitivity to aminoglycoside and carbapenem antibiotics and 100% resistance to third-generation cephalosporins. The most abundant Gram-positive bacteria was Staphylococcus aureus (17.5%), followed by S. haemolyticus (10.5%) and S. epidermidis (3.5%). All S. aureus were sensitive to linezolid, tigecycline, vancomycin, and macrolide antibiotics (azithromycin, clarithromycin, clindamycin, and erythromycin), whereas 50% were sensitive to some beta-lactams. However, 50% of S. aureus were methicillin resistant S. aureus (MRSA). Given the magnitude of multi-drug resistance, an empiric antimicrobial therapy in particular to specific settings and implementation of antibiotic stewardship programs are crucial.

Epidemiology of antimicrobial resistance in bacteria isolated from inpatient and outpatient samples, Ecuador, 2018.

To compare the epidemiology of antimicrobial resistance in bacteria isolated from inpatient and outpatient samples in Ecuador. A secondary analysis was done of data on bacteria isolated from inpatient and outpatient samples. Data were taken from the 2018 national antimicrobial resistance surveillance database of the National Reference Center for Antimicrobial Resistance. The variables included were: age, sex, inpatient versus outpatient setting, type of specimen, bacterial species identified, pattern of resistance to antibiotics, and geographic area. Data from 57 305 bacterial isolates were included in the study: 48.8% were from hospitalized patients, 55.7% were from women, and 60.1% were from patients older than 45 years. Urine (42.9%) and blood (12.4%) were the most common clinical samples. Overall, 77.1% of bacterial isolates were gram-negative (83% and 71% in outpatients and inpatients, respectively). The most common gram-positive and gram-negative species were Staphylococcus aureus and Escherichia coli, respectively. Antimicrobial resistance levels were high (up to 80% for some antimicrobial drugs), and were higher in hospitalized patients compared with outpatients. A variety of carbapenemases were found to confer resistance to carbapenems (antibiotics of last resort) in gram-negative bacteria. The study findings provide an important baseline on antimicrobial resistance in Ecuador. This will allow the strengthening of guidelines of the surveillance system, the creation of public policies for standardization of laboratory methodologies, the proper handling of information, and the development of empirical therapy guidelines based on local epidemiology.

Isolation of Carbapenem and Colistin Resistant Gram-Negative Bacteria Colonizing Immunocompromised SARS-CoV-2 Patients Admitted to Some Libyan Hospitals.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had a devastating effect, globally. We describe, for the first time, the occurrence of carbapenem-resistant bacteria colonizing SARS-CoV-2 patients who developed hospital-associated infections with carbapenemase-producing, Gram-negative bacteria at some isolation centers of SARS-CoV-2 in the eastern part of Libya. In total, at first, 109 samples were collected from 43 patients, with the samples being recovered from oral (n = 35), nasal (n = 45), and rectal (n = 29) cavities. Strain identification was performed via matrix assisted laser desorption ionization-time of flight (MALDI-TOF). Antibiotic susceptibility testing was carried out on Mueller-Hinton agar, using the standard disk diffusion method. MIC determination was confirmed via E-TEST and microdilution standard methods. A molecular study was carried out to characterize the carbapenem and colistin resistance in Gram-negative bacterial strains. All of the positive results were confirmed via sequencing. Klebsiella pneumoniae (n = 32), Citrobacter freundii (n = 21), Escherichia coli (n = 7), and Acinetobacter baumannii (n = 21) were the predominant isolated bacteria. Gram-negative isolates were multidrug-resistant and carried different carbapenem resistance-associated genes, including NDM-1 (56/119; 47.05%), OXA-48 (15/119; 12.60%), OXA-23 (19/119; 15.96%), VIM (10/119; 8.40%), and the colistin resistance mobile gene mcr-1 (4/119; 3.36%). The overuse of antimicrobials, particularly carbapenem antibiotics, during the SARS-CoV-2 pandemic has led to the emergence of multidrug-resistant bacteria, mainly K. pneumoniae, A. baumannii, and colistin-resistant E. coli strains. Increased surveillance as well as the rational use of carbapenem antibiotics and, recently, colistin are required to reduce the propagation of multidrug-resistant strains and to optimally maintain the efficacy of these antibiotics. IMPORTANCE In this work, we describe, for the first time, the occurrence of carbapenem-resistant bacteria colonizing COVID-19 patients who developed hospital-associated infections with carbapenemase-producing, Gram-negative bacteria at some isolation centers of COVID-19 in the eastern part of Libya. Our results confirmed that the overuse of antimicrobials, such as carbapenem antibiotics, during the COVID-19 pandemic has led to the emergence of multidrug-resistant bacteria, mainly K. pneumoniae and A. baumannii, as well as colistin resistance.

Epidemiology, drug resistance analysis and mortality risk factor prediction of gram-negative bacteria infections in patients with allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective treatment for many malignant and refractory diseases. However, infections, as the most common complication after transplantation, often lead to poor long-term prognosis of patients. In this study, we collected electronic medical records of allo-HSCT recipients with gram-negative bacteria (GNB) infections between January 2012 and September 2021, analyzed epidemiological characteristics and antibiotic sensitivity, and determined independent risk factors for carbapenem-resistant GNB (CR-GNB) infections and death by Logistic and Cox regression models. During the 9-year period, 183 of 968 patients developed GNB infections, of which 58 died. The most common pathogen was Klebsiella pneumoniae. CR-GNB, especially carbapenem-resistant Klebsiella pneumonia (CRKP), carbapenem-resistant Acinetobacter baumannii (CRAB) and carbapenem-resistant Escherichia coli (CREC) had a high resistance rate to commonly used clinical antibiotics. Independent risk factors for CR-GNB infections were use of carbapenem antibiotics for >3 days one month before transplantation (OR = 3.244, 95% CI 1.428–7.369, P = 0.005), use of special immunosuppressants after transplantation (OR = 1.21, 95% CI 1.008–1.452, P = 0.041), and time of hematopoietic reconstruction >20 days (OR = 2.628, 95% CI 1.369–5.043, P = 0.004). Independent risk factors for mortality were interval between diagnosis and transplantation >180 days (HR = 2.039, 95% CI 1.05 to 3.963, P = 0.035), total bilirubin levels during infection >34.2 μmol/L (HR = 3.39, 95% CI 1.583–7.256, P = 0.002) and septic shock (HR = 5.345, 95% CI 2.655–10.761, P = 0.000). In conclusion, GNB has a high incidence and mortality in allo-HSCT recipients. Early transplantation for eligible patients, attention to liver function protection, timely identification and treatment of septic shock can help to improve the prognosis of patients.

Efficacy of carbapenem vs non carbapenem β-lactam therapy as empiric antimicrobial therapy in patients with extended-spectrum β-lactamase-producing Enterobacterales urinary septic shock: a propensity-weighted multicenter cohort study

BackgroundThe rise in antimicrobial resistance is a global threat responsible for about 33,000 deaths in 2015 with a particular concern for extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) and has led to a major increase in the use of carbapenems, last-resort antibiotics.MethodsIn this retrospective propensity-weighted multicenter observational study conducted in 11 ICUs, the purpose was to assess the efficacy of non carbapenem regimen (piperacillin–tazobactam (PTZ) + aminoglycosides or 3rd-generation cephalosporin (3GC) + aminoglycosides) as empiric therapy in comparison with carbapenem in extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) urinary septic shock. The primary outcome was Day-30 mortality.ResultsAmong 156 patients included in this study, 69 received a carbapenem and 87 received non carbapenem antibiotics as empiric treatment. Baseline clinical characteristics were similar between the two groups. Patients who received carbapenem had similar Day-30 mortality (10/69 (15%) vs 6/87 (7%), OR = 1.99 [0.55; 5.34] p = 0.16), illness severity, resolution of septic shock, and ESBL-E infection recurrence rates than patients who received an empiric non carbapenem therapy. The rates of secondary infection with C. difficile were comparable.ConclusionsIn ESBL-E urinary septic shock, empiric treatment with a non carbapenem regimen, including systematically aminoglycosides, was not associated with higher mortality, compared to a carbapenem regimen.

Carbapenem Antibiotics Versus Other Antibiotics for Complicated Intra-abdominal Infections: a Systematic Review and Patient-Level Meta-analysis of Randomized Controlled Trials (PROSPERO CRD42018108854)

BackgroundThe treatment of complicated intra-abdominal infections remains a challenge. Both optimal medical and surgical therapy (i.e., source control) are needed to achieve low mortality and morbidity. The objective of this systematic review and meta-analysis is to determine the impact of carbapenem antibiotic therapy compared to other antibiotics in complicated intra-abdominal infections (secondary peritonitis) with an emphasis on mortality and postoperative complications. MethodsA systematic literature search from PubMed/Medline and Web of Science databases was carried out. The last search was conducted in August 2022. PRISMA guidelines were followed. Pre-defined outcomes were mortality, treatment success, treatment failure, and adverse events. ResultsTen randomized controlled trials, published from 1983 to 2013 with a total of 2377 patients (1255 patients in the carbapenem antibiotics group and 1122 in the control group), were identified. A meta-analysis comparing patients undergoing carbapenem antibiotic therapy and patients receiving other antibiotics was performed. No significant difference regarding mortality (OR 1.19, 95% CI [0.79; 1.82], p = 0.40), treatment success (OR 1.17, 95% CI [0.72; 1.91], p = 0.53), and treatment failure (OR 0.84, 95% CI [0.48; 1.45], p = 0.52) was observed. Carbapenem therapy was associated with fewer adverse events compared to therapy with other antibiotics (OR 0.79, 95% CI [0.65; 0.97], p = 0.022). ConclusionThere is currently no evidence that carbapenem antibiotics are superior in terms of mortality, and success or failure for the treatment of complicated intra-abdominal infections (secondary peritonitis). The rate of adverse events is lower under carbapenem therapy compared to control antibiotics. Trial RegistrationPROSPERO 2018 CRD42018108854.

Clinical impact of carbapenems in critically ill patients with valproic acid therapy: A propensity-matched analysis.

Valproic acid (VPA) is one of the most widely used broad-spectrum antiepileptic drugs, and carbapenems (CBPs) remain the drug of choice for severe infection caused by multidrug-resistant bacteria in critically ill patients. The interaction between VPA and CBPs can lead to a rapid depletion of serum VPA level. This may then cause status epilepticus (SE), which is associated with significant mortality. However, the prognostic impact of drug interactions in critically ill patients remains an under-investigated issue. The aim of this study was to compare the prognosis of critically ill patients treated with VPA and concomitant CBPs or other broad-spectrum antibiotics. Adult patients admitted to a medical center intensive care unit between January 2007 and December 2017 who concomitantly received VPA and antibiotics were enrolled. The risk of reduced VPA serum concentration, seizures and SE, mortality rate, length of hospital stay (LOS), and healthcare expenditure after concomitant administration were analyzed after propensity score matching. A total of 1,277 patients were included in the study, of whom 264 (20.7%) concomitantly received VPA and CBPs. After matching, the patients who received CBPs were associated with lower VPA serum concentration (15.8 vs. 60.8 mg/L; p < 0.0001), a higher risk of seizures (51.2 vs. 32.4%; adjusted odds ratio [aOR], 2.19; 95% CI, 1.48-3.24; p < 0.0001), higher risk of SE (13.6 vs. 4.7%; aOR, 3.20; 95% CI, 1.51-6.74; p = 0.0014), higher in-hospital mortality rate (33.8 vs. 24.9%; aOR, 1.57; 95% CI, 1.03-2.20; p = 0.036), longer LOS after concomitant therapy (41 vs. 30 days; p < 0.001), and increased healthcare expenditure (US$20,970 vs. US$12,848; p < 0.0001) than those who received other broad-spectrum antibiotics. The administration of CBPs in epileptic patients under VPA therapy was associated with lower VAP serum concentration, a higher risk of seizures and SE, mortality, longer LOS, and significant utilization of healthcare resources. Healthcare professionals should pay attention to the concomitant use of VPA and CBPs when treating patients with epilepsy. Further studies are warranted to investigate the reason for the poor outcomes and whether avoiding the co-administration of VPA and CBP can improve the outcomes of epileptic patients.

Analysis of Capped Silver Nanoparticles Combined with Imipenem against Different Susceptibility Profiles of Klebsiella pneumoniae

Klebsiella pneumoniae (K. pneumoniae) is an opportunistic bacterium that has drawn attention due to its resistance to carbapenem antibiotics. The treatment of patients with severe infections has been challenging. Thus, silver nanoparticles (AgNPs) have been applied for their antimicrobial effects. This work aims to analyze the synergistic effect of the carbapenem antibiotic Imipenem with AgNPs against different susceptibility clinical profiles of K. pneumoniae. The silver nanoparticles were synthesized by bottom-up methodology and capped with alpha-lipoic acid. Susceptibility tests were performed using four K. pneumoniae strains with different susceptibility profiles to Imipenem. The strains were induced to form a biofilm for 48 h. Crystal violet and Resazurin assays were performed to determine biofilm formation and minimal inhibitory concentration, respectively. The reduction in Imipenem concentration with the association of nanoparticles was found in all strains studied in planktonic form, and the synergism between silver nanoparticles and Imipenem was demonstrated through the analysis of the fractional inhibitory concentration index. The viability percentage was reduced at rates ≥80% in the biofilm analysis, characterized by the minimal biofilm inhibitory concentration. The study's proposed association resulted in inhibitory effects on different K. pneumoniae profiles, both in planktonic forms and biofilm, with peculiar behavior in the Imipenem-resistant profile.

Carbapenem-resistance worldwide: a call for action - correspondence.

Carbapenem-resistance worldwide: a call for action - correspondence.

Molecular docking and dynamic approach to screen the drug candidate against the Imipenem-resistant CarO porin in Acinetobacter baumannii

The multidrug-resistant Acinetobacter baumannii is an emerging nosocomial pathogen in the healthcare sector. Intrinsic resistance in A. baumannii is a significant problem framing a perfect treatment regimen. Also, this organism showed more resistance towards the carbapenem antibiotics, especially for imipenem and meropenem. The development of carbapenem-resistant Acinetobacter baumannii is mainly due to the alteration or loss of the porin region in the outer membrane. The most well-known porin in Acinetobacter baumannii is CarO (carbapenem-associated outer membrane protein). The CarO protein, which functions as a porin channel for carbapenem inflow, may contribute to carbapenem resistance. The current study identifies a potent drug candidate with a better binding affinity to the carbapenem-resistant outer membrane protein. We investigated the specificity of carbapenems such as imipenem, meropenem, ertapenem, biapenem, doripenem, and fluoroquinolone drugs such as sitafloxacin against the imipenem-resistant CarO protein was demonstrated using the computational approaches molecular docking and dynamic simulation for 50 ns. As a result, the high to low enzyme-ligand complex's binding affinity exhibited a greater binding affinity for ertapenem −7.76 kcal·mol−1 and sitafloxacin −7.75 kcal·mol−1 than biapenem, doripenem, meropenem, and imipenem. The molecular dynamic simulation and the MMPBSA analysis depicted ertapenem −55.431±25.908 kJ/mol and sitafloxacin −47.154 ± 11.052 kJ/mol with better binding affinity and more stability against the imipenem resistant CarO protein when it compared to other antibiotics.

Gut Microbiota as Well as Metabolomes of Wistar Rats Recover within Two Weeks after Doripenem Antibiotic Treatment.

An understanding of the changes in gut microbiome composition and its associated metabolic functions is important to assess the potential implications thereof on host health. Thus, to elucidate the connection between the gut microbiome and the fecal and plasma metabolomes, two poorly bioavailable carbapenem antibiotics (doripenem and meropenem), were administered in a 28-day oral study to male and female Wistar rats. Additionally, the recovery of the gut microbiome and metabolomes in doripenem-exposed rats were studied one and two weeks after antibiotic treatment (i.e., doripenem-recovery groups). The 16S bacterial community analysis revealed an altered microbial population in all antibiotic treatments and a recovery of bacterial diversity in the doripenem-recovery groups. A similar pattern was observed in the fecal metabolomes of treated animals. In the recovery group, particularly after one week, an over-compensation was observed in fecal metabolites, as they were significantly changed in the opposite direction compared to previously changed metabolites upon 28 days of antibiotic exposure. Key plasma metabolites known to be diagnostic of antibiotic-induced microbial shifts, including indole derivatives, hippuric acid, and bile acids were also affected by the two carbapenems. Moreover, a unique increase in the levels of indole-3-acetic acid in plasma following meropenem treatment was observed. As was observed for the fecal metabolome, an overcompensation of plasma metabolites was observed in the recovery group. The data from this study provides insights into the connectivity of the microbiome and fecal and plasma metabolomes and demonstrates restoration post-antibiotic treatment not only for the microbiome but also for the metabolomes. The importance of overcompensation reactions for health needs further studies.

Metagenomic Insight into Microbiome and Antibiotic Resistance Genes of High Clinical Concern in Urban and Rural Hospital Wastewater of Northern India Origin: a Major Reservoir of Antimicrobial Resistance.

India is one of the largest consumers and producers of antibiotics and a hot spot for the emergence and proliferation of antimicrobial resistance genes (ARGs). Indian hospital wastewater (HWW) accumulates ARGs from source hospitals and often merges with urban wastewater, with the potential for environmental and human contamination. Despite its putative clinical importance, there is a lack of high-resolution resistome profiling of Indian hospital wastewater, with most studies either relying on conventional PCR-biased techniques or being limited to one city. In this study, we comprehensively analyzed antibiotic resistomes of wastewater from six Indian hospitals distributed in rural and urban areas of northern India through shotgun metagenomics. Our study revealed the predominance of ARGs against aminoglycoside, macrolide, carbapenem, trimethoprim, and sulfonamide antibiotics in all the samples through both read-based analysis and assembly-based analysis. We detected the mobile colistin resistance gene mcr-5.1 for the first time in Indian hospital sewage. blaNDM-1 was present in 4 out of 6 samples and was carried by Pseudomonas aeruginosa in HWW-2, Klebsiella pneumoniae in HWW-4 and HWW-6, and Acinetobacter baumanii in HWW-5. Most ARGs were plasmid-mediated and hosted by Proteobacteria. We identified virulence factors and transposable elements flanking the ARGs, highlighting the role of horizontal gene transmission of ARGs. IMPORTANCE There is a paucity of research on detailed antibiotic resistome and microbiome diversity of Indian hospital wastewater. This study reports the predominance of clinically concerning ARGs such as the beta-lactamases blaNDM and blaOXA and the colistin resistance gene mcr and their association with the microbiome in six different Indian hospital wastewaters of both urban and rural origin. The abundance of plasmid-mediated ARGs and virulence factors calls for urgent AMR crisis management. The lack of proper wastewater management strategies meeting international standards and open drainage systems further complicates the problem of containing the ARGs at these hospitals. This metagenomic study presents the current AMR profile propagating in hospital settings in India and can be used as a reference for future surveillance and risk management of ARGs in Indian hospitals.

In Vitro and In Vivo Development of a β-Lactam-Metallo-β-Lactamase Inhibitor: Targeting Carbapenem-Resistant Enterobacterales.

β-lactams are the most prescribed class of antibiotics due to their potent, broad-spectrum antimicrobial activities. However, alarming rates of antimicrobial resistance now threaten the clinical relevance of these drugs, especially for the carbapenem-resistant Enterobacterales expressing metallo-β-lactamases (MBLs). Antimicrobial agents that specifically target these enzymes to restore the efficacy of last resort β-lactam drugs, that is, carbapenems, are therefore desperately needed. Herein, we present a cyclic zinc chelator covalently attached to a β-lactam scaffold (cephalosporin), that is, BP1. Observations from in vitro assays (with seven MBL expressing bacteria from different geographies) have indicated that BP1 restored the efficacy of meropenem to ≤ 0.5 mg/L, with sterilizing activity occurring from 8 h postinoculation. Furthermore, BP1 was nontoxic against human hepatocarcinoma cells (IC50 > 1000 mg/L) and exhibited a potency of (Kiapp) 24.8 and 97.4 μM against Verona integron-encoded MBL (VIM-2) and New Delhi metallo β-lactamase (NDM-1), respectively. There was no inhibition observed from BP1 with the human zinc-containing enzyme glyoxylase II up to 500 μM. Preliminary molecular docking of BP1 with NDM-1 and VIM-2 sheds light on BP1's mode of action. In Klebsiella pneumoniae NDM infected mice, BP1 coadministered with meropenem was efficacious in reducing the bacterial load by >3 log10 units' postinfection. The findings herein propose a favorable therapeutic combination strategy that restores the activity of the carbapenem antibiotic class and complements the few MBL inhibitors under development, with the ultimate goal of curbing antimicrobial resistance.

Retrospective analysis of drug resistance characteristics and infection related risk factors of multidrug-resistant organisms (MDROs) isolated from the orthopedics department of a tertiary hospital

Patients infected with multidrug-resistant organisms (MDROs) are known to exhibit longer hospital stays and a significantly poorer prognosis. We performed a 6-year retrospective analysis of nosocomial infections reported in the orthopedics department of our institution, to gain valuable insights into antibiotic sensitivity and infectious characteristics of MDROs, in order to deduce effective measures to control the occurrence of multidrug-resistant infections in clinical practice. A retrospective, single center surveillance study (January 2012–December 2017) was performed on the nosocomial infections recorded in the department of orthopedics. A nosocomial infection is defined as one that develops when a patient is residing in a hospital but was not present at the time of admission. All relevant data, including basic patient information, cultivated bacterial strains, and antimicrobial resistance, was obtained from the hospital information system. A total of 1392 strains of pathogenic bacteria were isolated; 358 belonged to MDROs (detection rate = 25.7%). All the isolated strains of MDROs were mostly from secretions (52.2%). The number of cases infected with MDROs were 144 (40.2%) and 129 (36.0%) in the trauma and spinal wards, respectively. MRSA showed high resistance to β lactam antibiotics, but was sensitive to quinolone antibiotics, linezolid and cotrimoxazole. ESBL-positive strains showed more sensitivity to carbapenem antibiotics (resistance rate < 10%). MDR nonfermenters showed high resistance to most antibiotics. Logistic multivariate analysis revealed age, open injury, and central nervous system injury as independent risk factors for multidrug resistant infections. A high antibiotic resistance rate and an increasing prevalence of infections with MDROs was identified in the orthopedics department. Patients with open injury, central nervous system injury and those aged ≥ 60 years, were more prone to multidrug-resistant infections. Clinicians should pay more attention to such patients in order to actively prevent and control the occurrence of infections caused by MDROs.

Quantitation of meropenem in dried blood spots using microfluidic-based volumetric sampling coupled with LC-MS/MS bioanalysis in preterm neonates

Meropenem, a carbapenem antibiotic, has been used for empirical and definitive therapy of severe infections for many years. Therapeutic drug monitoring (TDM) plays an indispensable role in the individualization of meropenem particularly in the preterm neonates, a population in which adjusting proper dosages has always been one of the most challenging tasks for their growth changes. In this report, a simple and accurate method for the quantitative analysis of meropenem in dried blood spot (DBS) samples by LC-MS/MS was developed. The traditional DBS drawbacks were conquered in this study by combining microfluidic-based volumetric sampling, shorten drying procedure, and sensitive detection. Moreover, the on-card stability of meropenem was improved obviously. The DBS-based method validation included hematocrit (Hct) effect, selectivity, carry-over, linearity, accuracy, precision, matrix effect, recovery and stability (high temperature and humidity). The calibration linear range of meropenem was 0.3–100 µg/mL. The acceptance criteria of accuracy (relative error < 4.53 %) and precision (coefficient of variation < 8.63 %) were met in all levels of quality control samples. The DBS samples was stable at 40 °C for 12 h, room temperature for 1 day, 4 °C for 7 days, −20 °C for 14 days and −40 °C for 30 days, respectively. A good correlation was observed between DBS concentration and plasma concentration of meropenem. There was 93.4 % of the samples between estimated plasma concentration and plasma concentration within 20 % of the mean of concentration, and no significant Hct effect was observed on the quantification. It has been successfully applied to samples derived from preterm neonates with severe infections. The supported data indicated that the DBS-based method using microfluidic-based volumetric sampling could be an alternative strategy to carry on TDM of meropenem in preterm neonates, with satisfactory performance and logistics advantages.

Meropenem Incorporated ZnO Nanoflakes as Nano Antibiotics: Efficient Antimicrobial Activity against Metallo β-lactamase Producing Clinical Isolates

The number of fatalities caused by multidrug-resistant (MDR) bacteria is over 700,000 annually due to widespread antibiotic usage. So, there is a need of new antibiotics, materials that work like antibiotics, or combinations of antibiotics with nanomaterials that could help in treating the infections which is caused by MDR bacteria. The present study describes the synthesis of ZnO nanoflakes using a co-precipitation method. The ZnO nanoflakes and ZnO nanoflakes combinations with carbapenem antibiotics were tested against carbapenem-resistant (CR) clinical isolates. The SEM analysis showed surface morphology of the synthesized nanoflakes-like structure of ZnO. All 67 CR isolates were tested and showed inhibitory action at varying concentrations of ZnO nanoflakes. ZnO nanoflakes were found to have an inhibitory effect against Escherichia coli and Klebsiella pneumoniae at lowest concentration of 1.25 mg.ml-1 of ZnO NPs with average zone size (mean ±SD) 1.91±2.94 mm and 2.00±4.14 mm and the average zone size of ZnO nanoflakes against Acinetobacter baumanni and Pseudomonas aeruginosa was 9.89±0.76 mm and 10.17±0.39 mm at 2.5 mg.ml-1 concentration. The combined action of ZnO nanoflakes with Meropenem 10 mcg demonstrated synergetic activity against CR pathogens, with an average zone of inhibition measuring 15.2 mm in diameter. ZnO nanoflakes illustrated considerable antibacterial activity against MBL-producing gram-negative clinical isolates at the lowest concentration. Chemically synthesized ZnO nanoflakes may offer a superior future expectation as a nano-antibiotic to treat the infection caused by CRE bacteria.

Drug use evaluation and rational prescription audit of restricted antibiotics in tertiary care corporate hospital: An interventional study

: Antimicrobial agent are the biggest contribution to 20th century, which are used to prevent and cure of the infections. Over use of antimicrobials has facilitated the development of resistance. Drug utilization research help in identification of clinical use of drugs in populations and its impact on healthcare system.: The aim of the study is to identify the overuse/misuse of the antibiotic usage in our intensive care unit. which helps in rationalising the antibiotic prescription and to avoid emergence of drug resistance and to improve better patient’s outcome. An observational audit has been conducted in inpatient admitted in our set up and has been prescribed with restricted antimicrobials. The audit has been done for 3 months. The Audit report for 218 patients have been prescribed with Restricted antimicrobials either one or more than one. The audit report shows that Meropenem and Colistin was prescribed more often 81 and 73 respectively. Geriatric Patients have been prrscribed more with Antimicrobials than other age groups. 193 patients were on single Restricted antimicrobial therapy, 24 patients were on dual restricted antimicrobial therapy and one patient was on more than 2 Restricted antimicrobial therapy. Out of 218 Prescription having Restricted Antibiotics, 39 prescription were found irrational. A wide spectrum of clinical diagnoses and a variety of drugs were utilized from various antibiotic classes. Results showed that Carbapenems(Meropenem) antibiotics were extensively used in ICU. Among Colistin and Vancomycin was most commonly prescribed. Policy for rational usage of restricted antimicrobial agents in ICU should be implemented and education needs to be provided.