Anti-MRSA drug use and antibiotic susceptibilities of MRSA at a university hospital in Japan from 2007 to 2011

Anti-MRSA activity of chlorophenyl pyrrolo benzodiazepines compound

Antibiotic resistant is the major concern in public health to control the infectious diseases. MRSA (Methicillin-resistant Staphylococcus aureus) is a significant concern in healthcare settings due to its resistance to many antibiotics, including methicillin and other beta-lactams. MRSA infection difficult to treat and increases the risk of complications. Here, we have tested a series of highly condensed heterocyclic derivatives of pyrrolo[1,2-a][1,4]benzodiazepines. Compounds were tested against both, Gram-positive bacteria, Staphylococcus aureus and S. epidermidis, and Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa, to assess the antimicrobial efficacy. Compared to Gram-negative bacteria, compounds showed much stronger antibacterial activity against Gram-positive bacteria. SM-5 [Ethyl2-(7-(4-chlorophenyl)-4-methoxy-6,7,8,13-tetrahydro-5H-benzo[e]benzo[5,6][1,4]diazepino[2,1-a]isoindol-15-yl)acetate] derivative was selected as best on the basis of higher therapeutic index among the tested compounds, showed MIC value of 7.81 µg. ml-1 against Staphylococcus strains. Molecular docking analysis between cell wall biosynthesis protein of S. aureus and SM-5 revealed that PBP2a showed the highest binding energy (-8.3 Kcal mol-1), followed by beta-lactam-inducible PBP4 (-7.7 Kcal mol-1), and lipoteichoic acid synthase (-7.5 Kcal mol-1) which is comparably higher than methicillin. Ground state energy calculations by DFT analysis revealed that compound SM-5 and SM-6, almost have equal electronegativity 0.11018 au which also satisfy the quality of the compound reactivity. Analysis of their biofilm inhibition in vitro and in silico toxicity analysis demonstrated their substantial potential to be a kind of future lead antibiotic.

Bacterial Targets of Antibiotics in Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most prevalent bacterial pathogens and continues to be a leading cause of morbidity and mortality worldwide. MRSA is a commensal bacterium in humans and is transmitted in both community and healthcare settings. Successful treatment remains a challenge, and a search for new targets of antibiotics is required to ensure that MRSA infections can be effectively treated in the future. Most antibiotics in clinical use selectively target one or more biochemical processes essential for S. aureus viability, e.g., cell wall synthesis, protein synthesis (translation), DNA replication, RNA synthesis (transcription), or metabolic processes, such as folic acid synthesis. In this review, we briefly describe the mechanism of action of antibiotics from different classes and discuss insights into the well-established primary targets in S. aureus. Further, several components of bacterial cellular processes, such as teichoic acid, aminoacyl-tRNA synthetases, the lipid II cycle, auxiliary factors of β-lactam resistance, two-component systems, and the accessory gene regulator quorum sensing system, are discussed as promising targets for novel antibiotics. A greater molecular understanding of the bacterial targets of antibiotics has the potential to reveal novel therapeutic strategies or identify agents against antibiotic-resistant pathogens.

An alternative index for evaluating AMU and anti-methicillin-resistant Staphylococcus aureus agent use: A study based on the National Database of Health Insurance Claims and Specific Health Checkups data of Japan

INTRODUCTION

Anti-methicillin-resistant Staphylococcus aureus (MRSA) agents have different doses and administration periods. Thus, it is difficult to evaluate antimicrobial use (AMU) of anti-MRSA agents using defined daily doses per 1000 inhabitants per day (DID) or days of therapy per 1000 inhabitants per day (DOTID). This study aimed to evaluate the relationship between anti-MRSA agent use and resistant bacteria using the number of patients per 1000 inhabitants per day (PID) as an alternative index of AMU.

METHODS

AMU data for anti-MRSA agents were collected from the National Database of Health Insurance Claims and Specific Health Checkups (NDB) in 2016. The relationship between PID and DID or DOTID was evaluated. The number of patients with MRSA isolated was obtained from Japan Nosocomial Infections Surveillance, and their correlation with PID was analyzed. The rate of anti-MRSA agent use in each prefecture was investigated.

RESULTS

PID showed a significant linear relationship with both DID and DOTID (all p < 0.0001). PID was significantly correlated with the number of patients with MRSA isolated. Additionally, the rate of anti-MRSA agent use was markedly different in each region.

CONCLUSIONS

PID is not affected by doses and administration periods, and thus may be an alternative index for the selective pressure of antibiotics. Evaluating AMU using PID based on NDB data will help in the development of effective antimicrobial resistance measures.

A new carbapenem drug dosage metric for carbapenem usage and correlation with carbapenem resistance of Pseudomonas aeruginosa

The emergence and dissemination of antimicrobial resistance is a worldwide problem. Inappropriate antimicrobial use contributes to this resistance, and several metrics of drug usage have been used to monitor their consumption and rational use. We examined several existing drug metrics, and developed a new one, dose/duration-density (D/d²), for a the best correlation between carbapenem usage and carbapenem resistance of Pseudomonas aeruginosa. The annual changes of antimicrobial use density (AUD), days of therapy (DOT), daily dose (DD) and D/d² for meropenem, imipenem and total carbapenems was analyzed for a correlation with carbapenem susceptibility of P. aeruginosa from 2006 through 2015 at a university hospital. The substitution of meropenem for imipenem usage, and an approximate 10% increase in carbapenem susceptibility of P. aeruginosa occurred over the study period. There were significant correlations of the meropenem susceptibility of P. aeruginosa and meropenem usage as measured by the meropenem DD, of imipenem susceptibility and imipenem AUD and DOT, and overall carbapenem susceptibility and imipenem DOT. The D/d² for meropenem, imipenem and total carbapenems had significant correlations with individual and all carbapenem susceptibility of P. aeruginosa. These D/d² is the best single carbapenem use metric for correlating carbapenem usage with P. aeruginosa resistance. Further studies are warranted to consider the value of D/d² for other antimicrobials and bacteria.

Comparison between local and national epidemiology of antimicrobial resistance using the JANIS data

The Japanese Ministry of Health, Labor and Welfare established the Japanese Nosocomial Infection Surveillance (JANIS) system in July 2000 to provide nationwide epidemiological information. The data of all clinically isolated bacteria at participating hospitals were collected, treated according to a protocol, and analyzed by the JANIS office. Nationwide and individual hospital data were reported to participating hospitals monthly and yearly. In this study, we surveyed local antimicrobial resistance of clinically isolated bacteria in Kawasaki City between 2014 and 2016 using JANIS data. There were 8, 14, and 16 major hospitals in Kawasaki City that participated in the surveillance in 2014, 2015, and 2016, respectively. The data were returned to each hospital monthly from JANIS, totaled for Kawasaki City, and compared with the nationwide data. The Kawasaki City data were approximately the same as the nationwide data, and most resistant bacteria decreased gradually over the three years examined. The incidence of methicillin-resistant Staphylococcus aureus (MRSA) in S. aureus (Kawasaki City, Japan) was (56.6%, 48.8%), (50.5%, 47.9%), and (51.6%, 46.9%), the incidence of penicillin-resistant Streptococcus pneumoniae (PRSP) in S. pneumoniae, was (43.4%, 37.5%), (34.3%, 38.0%), and (31.4%, 36.9%) in 2014, 2015, and 2016, respectively. Therefore, in Kawasaki City the incidence of MRSA was relatively higher and that of PRSP was relatively lower than the nationwide incidences. Both continuous local and national surveillance are important for monitoring antimicrobial resistance in clinical isolates. The JANIS database is a powerful tool for the epidemiology of nosocomial infections in Japanese hospitals.

Antimicrobial resistance rates in gram-positive bacteria do not drive glycopeptides use

Surveillance data are considered essential to appropriate empiric antibiotic therapy and stewardship. The objective of this study was to determine if a change in the rates of antibiotic resistance impacts antibiotic use in European hospitals. Glycopeptides use was selected to study the correlation between resistance rates and antibiotic use because of the restricted spectrum against resistant gram positive bacteria. PubMed, ECDC databases and national/regional surveillance systems were searched to identify glycopeptides´ consumption in defined daily dose per 1000 inhabitant-days (DID) and rate of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase negative staphylococci (MRCoNS), and vancomycin-resistant enterococci (VRE) in bloodstream infections (BSIs) in European countries between 1997 and 2015. Time trends were studied and associations between DID and BSI resistance rates were tested using multi-level mixed effect models. To account for the gap in the publication and dissemination of the yearly resistance data, a 2-year lag in the resistance rates was applied. Data on glycopeptides´ DID and resistance rates of target microorganisms in blood cultures were identified among 31 countries over a 19-year period. Glycopeptides use significantly increased (p<0·0001) while rates of MRSA BSIs decreased in majority of the countries (p<0·0001) and MRCoNS and VRE BSIs remained stable. Variation in glycopeptides' DID was not associated with variation in BSIs due to MRSA (p = 0·136) and VRE (p = 0·613). After adjusting for MRCoNS and VRE resistance rates, among 21 countries, 11 (52%) had a concordant and 10 (48%) a discordant trend in yearly glycopeptides´ DID and MRSA BSI rates. No correlation was found between resistance rates and DID data even among 8 countries with more than 5% decrease in MRSA rates over time. (RC -0·009, p = 0·059). Resistance rate of MRSA, MRCoNS, and VRE BSIs does not impact DID of glycopeptides in European hospitals. This finding is key to redefining the role and structure of antimicrobial surveillance and stewardship programmes.

Synthesis and antibacterial activity of 4″ or 6″-alkanoylamino derivatives of arbekacin

Arbekacin, an aminoglycoside antibiotic, is an important drug because it shows a potent efficacy against methicillin-resistant Staphylococcus aureus. However, resistance to arbekacin, which is caused mainly by the bifunctional aminoglycoside-modifying enzyme, has been observed, becoming a serious problem in medical practice. To create new arbekacin derivatives active against resistant bacteria, we modified the C-4″ and 6″ positions of its 3-aminosugar portion. Regioselective amination of the 6″-position gave 6″-amino-6″-deoxyarbekacin (1), and it was converted to a variety of 6″-N-alkanoyl derivatives (6a-z). Furthermore, regioselective modifications of the 4″-hydroxyl group were performed to give 4″-deoxy-4″-epiaminoarbekacin (2) and its 4″-N-alkanoyl derivatives (12 and 13). Their antibacterial activity against S. aureus, including arbekacin-resistant bacteria, was evaluated. It was observed that 6″-amino-6″-N-[(S)-4-amino-2-hydroxybutyryl]-6″-deoxyarbekacin (6o) showed excellent antibacterial activity, even better than arbekacin.