Integron distribution and relationship to antimicrobial resistance in E. coli isolated from blood culture

PURPOSE

The aim of this study was to evaluate the distribution of integrons in strains of E. coli isolated from blood culture and the relationship between integrons and antimicrobial resistance.

METHODS

The study included 100 E. coli strains sent to the Medical Microbiology Laboratory from different clinics between September 2022 and June 2023. Antibiotic susceptibility was evaluated according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The presence of integrons was determined by the inhouse polymerase chain reaction (PCR).

RESULTS

Integron positivity was detected in 45 (45%) of isolates, and class 1 integrons were found in 41 (41%), class 2 integrons in 2 (2%), and both class 1 integrons and class 2 integrons in 2 (2%). Class 3 integron positivity was not detected. In total, 63 cases of community origin and 37 cases of hospital origin were identified. When antibiotic resistance was evaluated, the highest sensitivity was noted for amikacin (1%), meropenem (5%), imipenem (6%), and the highest resistant antibiotics were ampicillin (82%), cepfuroxime sodium (65%), and amoxicillin/clavulanate (62%), respectively. Of the 16 antimicrobial substances evaluated, 10 had an antibiotic resistance rate of over 45%. In class 1 integron-positive samples, ampicillin resistance and trimethoprim/sulfamethoxazole resistance were higher than in negative samples (p = 0.02, p = 0.0001, respectively). Fifty-one (51%) samples were found to have multiple drug resistance (MDR). In total, 59.5% of hospital-acquired isolates and 46% of community-acquired isolates were considered to be MDR. The class 1 integron positivity in MDR samples was high (p = 0.038).

CONCLUSION

The high MDR rates in both hospital-acquired and community-acquired isolates are alarming. In particular, class 1 integron monitoring is very important to prevent the spread of MDR isolates.

Bacteriological and molecular study of fosfomycin resistance in uropathogenic Escherichia coli

The identification of genes associated with resistance has the potential to facilitate the development of novel diagnostic tests and treatment methods. The objective of this study was to examine the antibiotic resistance and Fosfomycin resistance genes in uropathogenic Escherichia coli (UPEC) in patients in Baghdad, Iraq. After analyzing 250 urine samples using various identification methods, including the examination of morphological characteristics, biochemical tests, and genetic detection, it was determined that E. coli was the most common bacteria present, accounting for 63.6% of the samples. Antibiotic susceptibility testing showed a significant prevalence of resistance to various antibiotics, with 99.3% of E. coli isolates exhibiting multiple drug resistance (MDR). Fosfomycin showed antibacterial properties against UPEC. The minimum inhibitory concentration (MIC) ranged from 512 to 1024 μg/mL, while the minimum bactericidal concentration (MBC) was 2048 μg/mL. In the time-kill assay, fosfomycin was effective against fosfomycin-resistant isolates within 8-12 h. The genetic determinants associated with fosfomycin resistance were examined through the utilization of polymerase chain reaction (PCR). The findings indicated that the genes murA, glpT, and cyaA were detected in all the isolates when genomic DNA was used as a template. However, all the tests yielded negative results when plasmid was used as a template. The genes fosA3 and fosA4 were detected in 8.6% and 5% of the isolates when genomic DNA was used as a template. When plasmid was used as a template, the genes fosA3 and fosA4 were found in 5.7% and 2.9% of the isolates, respectively. In conclusion, there is an increasing problem with antibiotic resistance in UPEC, with elevated rates of resistance to several antibiotics. The study also offers novel insights into the genetic foundation of fosfomycin resistance in UPEC.

Antimicrobial resistance survey and whole-genome analysis of nosocomial P. Aeruginosa isolated from eastern Province of China in 2016-2021

BACKGROUND

Pseudomonas aeruginosa is a major Gram-negative pathogen that can exacerbate lung infections in the patients with cystic fibrosis, which can ultimately lead to death.

METHODS

From 2016 to 2021, 103 strains of P. aeruginosa were isolated from hospitals and 20 antibiotics were used for antimicrobial susceptibility determination. Using next-generation genome sequencing technology, these strains were sequenced and analyzed in terms of serotypes, ST types, and resistance genes for epidemiological investigation.

RESULTS

The age distribution of patients ranged from 10 days to 94 years with a median age of 69 years old. The strains were mainly isolated from sputum (72 strains, 69.9%) and blood (14 strains, 13.6%). The size of these genomes ranged from 6.2 Mb to 7.4 Mb, with a mean value of 6.5 Mb. In addition to eight antibiotics that show inherent resistance to P. aeruginosa, the sensitivity rates for colistin, amikacin, gentamicin, ceftazidime, piperacillin, piperacillin-tazobactam, ciprofloxacin, meropenem, aztreonam, imipenem, cefepime and levofloxacin were 100%, 95.15%, 86.41%, 72.82%, 71.84%, 69.90%, 55.34%, 52.43%, 50.49%, 50.49%, 49.51% and 47.57% respectively, and the carriage rate of MDR strains was 30.69% (31/101). Whole-genome analysis showed that a total of 50 ST types were identified, with ST244 (5/103) and ST1076 (4/103) having a more pronounced distribution advantage. Serotype predictions showed that O6 accounted for 29.13% (30/103), O11 for 23.30% (24/103), O2 for 18.45% (19/103), and O1 for 11.65% (12/103) of the highest proportions. Notably, we found a significantly higher proportion of ExoU in P. aeruginosa strains of serotype O11 than in other cytotoxic exoenzyme positive strains. In addition to this, a total of 47 crpP genes that mediate resistance to fluoroquinolones antibiotics were found distributed on 43 P. aeruginosa strains, and 10 new variants of CrpP were identified, named 1.33, 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, 1.40, 1.41 and 7.1.

CONCLUSIONS

We investigated the antibiotic susceptibility of clinical isolates of P. aeruginosa and genomically enriched the diversity of P. aeruginosa for its prophylactic and therapeutic value.

Computational Study of Antimicrobial Peptides for Promising Therapeutic Applications Against Methicillin-resistant Staphylococcus Aureus

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is a causative agent for multiple drug-resistant diseases and is a prime health concern. Currently, antibiotics like vancomycin, daptomycin, fluoroquinolones, linezolid, fifth-generation cephalosporin and others are available in the market for the treatment of MRSA infection.

METHODS

With the increasing prevalence of drug-resistant cases, researchers are actively investigating alternative strategies to combat MRSA, including the exploration of peptide therapeutics. This study employed computational methods to prospect for potential Antimicrobial Peptides (AMPs).

RESULTS

A total of One hundred and fifty antimicrobial peptides were explored based on physicochemical properties. The results showed that Clavanin B was the most appropriate candidate. Molecular Docking and Molecular Dynamics Simulation results showed the protein-peptide interaction of the MRSA target proteins, Penicillin Binding Protein 2a and Panton-Valentine Leukocidin Toxin, with the Antimicrobial Peptide Clavanin B.

CONCLUSION

Currently, the antimicrobial peptide database highlights Clavanin B's role as an anti-HIV peptide. Moreover, this investigation proposes Clavanin B as a viable repurposed drug for treating MRSA, underscoring its potential deployment in the management of MRSA infections.

An Overview of the Global Alarming Increase of Multiple Drug Resistant: A Major Challenge in Clinical Diagnosis

The increased spreading of antibiotic resistance among different infectious agents has been a fast-growing public health challenge worldwide; this is because of the discovery of new resistance mechanisms and the reduction in quality and effective treatments of general pathogenic infections. This has caused unsuccessful microbial responses to standard therapy, which could lead to a higher risk of mortality, prolonged illness, and more expenditures for health care. Most parasites, bacteria, fungi, and viruses can produce a higher degree of multidrug resistance (MDR) with increased mortality and morbidity. Moreover, the establishment of MDR can be a natural phenomenon, improper utilization of antimicrobial drugs, lack of proper sanitary conditions, poor method of food handling, and absence of infection prevention and control (IPC), which could be responsible for the further spreading of MDR. Moreover, MDR helminth's mechanism of action can occur via genetic alterations in the drug transport, metabolisms and target sites. MDR bacterial mode of action such as cell wall synthesis inhibitors, DNA synthesis inhibitors and so on. However, there have been different approaches to managing and preventing multi-drug resistance. Hence, this review's aim is to educate the public about the global increase of multiple drug resistance and the danger ahead if appropriate measures are not put in place to combat microbial infections.

Dynamics of antimicrobial resistance and virulence of staphylococcal species isolated from foods traded in the Cape Coast metropolitan and Elmina municipality of Ghana

The impact of staphylococci on food poisoning and infections could be higher than previously reported. In this study, we characterised the occurrence and coexistence of antimicrobial resistance and virulence genes of staphylococci isolates in foods. Staphylococci were isolated from 236 samples of selected street-vended foods and identified. The pattern of antimicrobial resistance and virulence genes in the staphylococci were assessed using disc diffusion, PCR and analysis of next-generation sequencing data. The food samples (70.76 %) showed a high prevalence of staphylococci and differed among the food categories. Forty-five Staphylococcus species were identified and comprised coagulase-negative and positive species. Staphylococcus sciuri (now Mammaliicoccus sciuri), S. aureus, S. kloosii, S. xylosus, S. saprophyticus, S. haemolyticus and S. succinus were the most abundant species. The staphylococcal isolates exhibited resistance to tetracycline, levofloxacin, ciprofloxacin, norfloxacin, gentamicin and amikacin and susceptibility to nitrofurantoin. Antimicrobial susceptibilities were also reported for cefoperazone, ceftriaxone, cefotaxime, nalidixic acid and piperacillin-tazobactam. The antimicrobial resistance and virulence genes commonly detected consisted of tet, arl, macB, van, gyr, nor, optrA, bcrA, blaZ, taeA and S. aureus lmrS. The isolates frequently exhibited multiple resistance (30.42 %) of up to eight antimicrobial drug classes. The isolates predominantly harboured genes that express efflux pump proteins (50.53 %) for antibiotic resistance compared with inactivation (10.05 %), target alteration (26.72 %), protection (7.67 %) and replacement (3.17 %). The virulence determinants comprised genes of pyrogenic toxin superantigens (eta, etb, tst), adhesions (clf, fnbA, fnbB, cna, map, ebp, spA, vWbp, coa) and genes that express exoproteins (nuclease, metalloprotease, γ-hemolysin, hyaluronate lyase). There was a statistically significant difference in the prevalence of staphylococci isolates and their antimicrobial resistance and virulence profile as revealed by the phenotypic, PCR and next-generation sequencing techniques. The findings suggest a higher health risk for consumers. We recommend a critical need for awareness and antimicrobial susceptibility and anti-virulence strategies to ensure food safety and counteract the spread of this clinically relevant genus.

It is the time for quorum sensing inhibition as alternative strategy of antimicrobial therapy

Multiple drug resistance poses a significant threat to public health worldwide, with a substantial increase in morbidity and mortality rates. Consequently, searching for novel strategies to control microbial pathogenicity is necessary. With the aid of auto-inducers (AIs), quorum sensing (QS) regulates bacterial virulence factors through cell-to-cell signaling networks. AIs are small signaling molecules produced during the stationary phase. When bacterial cultures reach a certain level of growth, these molecules regulate the expression of the bound genes by acting as mirrors that reflect the inoculum density.Gram-positive bacteria use the peptide derivatives of these signaling molecules, whereas Gram-negative bacteria use the fatty acid derivatives, and the majority of bacteria can use both types to modulate the expression of the target gene. Numerous natural and synthetic QS inhibitors (QSIs) have been developed to reduce microbial pathogenesis. Applications of QSI are vital to human health, as well as fisheries and aquaculture, agriculture, and water treatment. Video Abstract.

High burden of MDR, XDR, PDR, and MBL producing Gram negative bacteria causing infections in Kermanshah health centers during 2019-2020

Background and Objectives

Microorganisms producing Metallo-Beta-Lactamase (MBL) are a threat and cause of concern as they have become one of the most feared resistance mechanisms. This study was designed to explore the prevalence of MBL production in clinical isolates of Gram negative bacteria using phenotypic MBL detection.

Materials and Methods

A total of 248 isolates were collected from various clinical samples and were evaluated for carbapenem resistance and MBL production. All strains were screened for MBL production using Double Disk Confirmatory Test (DDCT).

Results

The results of screening for MBL production using phenotypic disk diffusion method showed that in the 85 isolates were carbapenemase positive; including, 10 (16.1%) Klebsiella pneumoniae, 9 (14.5%) Escherichia coli, 58 (93.6%) Acinetobacter baumannii, and 8 (12.9%) Pseudomonas aeruginosa isolates. Also, 83 (97.6) Carbapenemase-producing isolates were resistant to at least four classes of antimicrobials (MDR).

Conclusion

A. baumannii was the most common carbapenem resistant bacterium in medical centers in Kermanshah. Significant multiple drug resistance (MDR) incidence was observed compared to different classes of antibiotics.

Role of bacterial efflux pump proteins in antibiotic resistance across microbial species

Efflux proteins are transporter molecules that actively pump out a variety of substrates, including antibiotics, from cells to the environment. They are found in both Gram-positive and Gram-negative bacteria and eukaryotic cells. Based on their protein sequence homology, energy source, and overall structure, efflux proteins can be divided into seven groups. Multidrug efflux pumps are transmembrane proteins produced by microbes to enhance their survival in harsh environments and contribute to antibiotic resistance. These pumps are present in all bacterial genomes studied, indicating their ancestral origins. Many bacterial genes encoding efflux pumps are involved in transport, a significant contributor to antibiotic resistance in microbes. Efflux pumps are widely implicated in the extrusion of clinically relevant antibiotics from cells to the extracellular environment and, as such, represent a significant challenge to antimicrobial therapy. This review aims to provide an overview of the structures and mechanisms of action, substrate profiles, regulation, and possible inhibition of clinically relevant efflux pumps. Additionally, recent advances in research and the pharmacological exploitation of efflux pump inhibitors as a promising intervention for combating drug resistance will be discussed.

Inhibitors of ABCG2-mediated multidrug resistance: Lead generation through computer-aided drug design

Human breast cancer resistance protein (BCRP), known also as ABCG2, plays a major role in multiple drug resistance (MDR) in tumor cells. Through this ABC transporter, cancer cells acquire the ability of resistance to structurally and functionally unrelated anticancer drugs. Nowadays, the design of ABCG2 inhibitors as potential agents to enhance the chemotherapy efficacy is an interesting strategy. In this context, we have used computer-aided drug design (CADD) based on available data of a large series of potent inhibitors from our groups as an approach in guiding the design of effective ABCG2 inhibitors. We report therein the results on the use of the FLAPpharm method to elucidate the pharmacophoric features of one of the ABCG2 binding sites involved in the regulation of the basal ATPase activity of the transporter. The predictivity of the model was evaluated by testing three predicted compounds which were found to induce high inhibitory activity of BCRP, in the nanomolar range for the best of them.

Lower SLC7A2 expression is associated with enhanced multidrug resistance, less immune infiltrates and worse prognosis of NSCLC

BACKGROUND

Solute carrier family 7 member 2 (SLC7A2), a cationic amino acid transporter, is lowly expressed in ovarian and hepatocellular cancers, which is associated with their worse prognosis. However, its roles in the prognosis, drug resistance and immune infiltration in non-small-cell lung cancer (NSCLC) are unclear.

METHODS

We chose SLC7A2 from RNA-Seq of paclitaxel/cisplatin-resistant A549 cells, then bioinformatics, cell lines construction, RT-qPCR, and CCK8 were performed to investigate SLC7A2 role.

RESULT

We analyzed the 223 differentially expressed genes (DEGs) from RNA-Seq of paclitaxel/cisplatin-resistant A549 cells and found that SLC7A2 expression was down-regulated in NSCLC. Lower SLC7A2 expression was associated with worse recurrence-free survival (RFS) in NSCLC. SLC7A2 silencing enhanced the proliferation of NSCLC cells and their insensitivity to paclitaxel, cisplatin, and gemcitabine in vitro. Activation of AMPK has up-regulated SLC7A2 expression and enhanced the sensitivity of NSCLC cells to anti-tumor drugs, which could be attributed to E2F1's regulation. In addition, the levels of SLC7A2 expression were correlated to the numbers of infiltrated neutrophils, macrophages, dendritic cells and their marker genes, like CD86, HLA-DPA1 and ITGAM.

CONCLUSIONS

SLC7A2 may act as a tumor suppressor to modulate drug sensitivity, immune infiltration and survival in NSCLC. Video abstract.

Anti-microbial Peptides against Methicillin-resistant Staphylococcus aureus: Promising Therapeutics

BACKGROUND

Multidrug-resistant (MDR) methicillin-resistant Staphylococcus aureus (MRSA) has become a prime health concern globally. These bacteria are found in hospital areas where they are regularly dealing with antibiotics. This brings many possibilities for its mutation, so drug resistance occurs.

INTRODUCTION

Nowadays, these nosocomial MRSA strains spread into the community and live stocks. Resistance in Staphylococcus aureus is due to mutations in their genetic elements.

METHODS

As the bacteria become resistant to antibiotics, new approaches like antimicrobial peptides (AMPs) play a vital role and are more efficacious, economical, time, and energy saviours.

RESULTS

Machine learning approaches of Artificial Intelligence are the in silico technique which has their importance in better prediction, analysis, and fetching of important details regarding AMPs.

CONCLUSION

Anti-microbial peptides could be the next-generation solution to combat drug resistance among Superbugs. For better prediction and analysis, implementing the in silico technique is beneficial for fast and more accurate results.

Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Causing Invasive Pneumococcal Disease in Korea Between 2017 and 2019 After Introduction of the 13-Valent Pneumococcal Conjugate Vaccine

Background

Streptococcus pneumoniae is a serious pathogen causing various infections in humans. We evaluated the serotype distribution and antimicrobial resistance of S. pneumoniae causing invasive pneumococcal disease (IPD) after introduction of pneumococcal conjugate vaccine (PCV)13 in Korea and investigated the epidemiological characteristics of multidrug-resistant (MDR) isolates.

Methods

S. pneumoniae isolates causing IPD were collected from 16 hospitals in Korea between 2017 and 2019. Serotyping was performed using modified sequential multiplex PCR and the Quellung reaction. Antimicrobial susceptibility tests were performed using the broth microdilution method. Multilocus sequence typing was performed on MDR isolates for epidemiological investigations.

Results

Among the 411 S. pneumoniae isolates analyzed, the most prevalent serotype was 3 (12.2%), followed by 10A (9.5%), 34 (7.3%), 19A (6.8%), 23A (6.3%), 22F (6.1%), 35B (5.8%), 11A (5.1%), and others (40.9%). The coverage rates of PCV7, PCV10, PCV13, and pneumococcal polysaccharide vaccine (PPSV)23 were 7.8%, 7.8%, 28.7%, and 59.4%, respectively. Resistance rates to penicillin, ceftriaxone, erythromycin, and levofloxacin were 13.1%, 9.2%, 80.3%, and 4.1%, respectively. MDR isolates accounted for 23.4% of all isolates. Serotypes 23A, 11A, 19A, and 15B accounted for the highest proportions of total isolates at 18.8%, 16.7%, 14.6%, and 8.3%, respectively. Sequence type (ST)166 (43.8%) and ST320 (12.5%) were common among MDR isolates.

Conclusions

Non-PCV13 serotypes are increasing among invasive S. pneumoniae strains causing IPD. Differences in antimicrobial resistance were found according to the specific serotype. Continuous monitoring of serotypes and antimicrobial resistance is necessary for the appropriate management of S. pneumoniae infections.

Clinical evaluation of a new molecular method for the detection of multidrug-resistant microorganisms

INTRODUCTION

The main objective of this work is to carry out the clinical validation of the trial with the AMR Direct Flow Chip starting from either nasal swabs, rectal swabs directly or from isolated strains to detect antibiotic resistance genes.

METHODS

We developed the preclinical validation of the assay with 104 known bacterial isolates. A total of 210 nasal or rectal swab samples were analyzed. The AMR assay is based on multiplex PCR followed by reverse dot blot hybridization on DNA arrays fully automated by using the HS24 platform.

RESULTS

Both the sensitivity and specificity of the preclinical assay were 100%, with the 104 samples correctly identified. In the clinical validation, the sensitivity was 100% and the specificity was between 100% in nasal swabs and 97% in rectal swabs.

CONCLUSIONS

The AMR Direct Flow Chip® is a rapid and effective assay for the detection of multidrug-resistant microorganisms (MDR) from nasal and rectal swab samples.

Evaluation of sulbactam and colistin/sulbactam efficacy against multiple resistant Acinetobacter baumannii blood isolates

PURPOSE

We aimed to compare the results of the BD Phoenix (TM) M50 ID/AST system and the gold standard broth microdilution method. We also evaluated the potential of a new therapeutic combination (colistin/sulbactam) for colistin resistance among Acinetobacter baumanni strains.

METHODS

Growth in blood samples was detected with the BACTEC (BD Becton Dickinson, ABD) continuous monitoring blood culture system. Strains were identified by Phoenix (BD Phoenix™ M50, ABD) automated bacterial identification system and antimicrobial susceptibility results were obtained. A total of 92 A. baumannii complex isolates showing resistance to at least three antibiotic classes were included in the study. Colistin susceptibility results (both susceptible and resistant strains) detected by the Phoenix device were confirmed by the reference method, the liquid microdilution method. The concentration index (FIC) was used to determine the efficacy of fractional inhibitor drug combinations, the efficacy of colistin/sulbactam combination against 50 multiresistant A. baumannii complex strains was investigated using the checkerboard method.

RESULTS

10 (10.9%) of 92 isolates were resistant to colistin and 80 (86.9%) to sulbactam. With the automation system, only 2 of 10 isolates were found resistant to colistin, while 8 isolates were susceptible. For this reason, the very major error rate of the Phoenix M50 automatic system among resistant isolates was determined as 8/10. It was determined that 6 (12%) of the colistin/sulbactam combination had a synergistic effect and 44 (88%) had an additive interaction. No antagonistic interaction was detected with the colistin-sulbactam combination in this study.

CONCLUSION

A. baumannii strains should be confirmed by the broth microdilution method, which is the reference method, against the MIC results detected by automated systems. It was concluded that the use of colistin alone should be avoided in the treatment of A. baumannii infections.

Molecular Study of Integrase Gene I and Integrase Gene II in Clinical Isolates of Pseudomonas aeruginosa

BACKGROUND

The presence of class I integron gene is associated with the emergence of multiple drug resistance [MDR] phenotype in Pseudomonas aeruginosa [P. aeruginosa] isolates.

AIM

The objectives were to study the prevalence of integrase genes I and II [Intel I & Intel II] in clinical isolates of P. aeruginosa and its association with antibiotics resistance in these isolates.

METHODS

The study was a retrograde cross-sectional study that was carried out on 150 clinical isolates of P. aeruginosa isolated from patients with health care associated infections. The isolates were subjected to biochemical identification and antibiotics sensitivity study by discs diffusion test. Intel I & Intel II genes were detected by polymmulerase chain reaction [PCR].

RESULTS

Intel I gene was present in 48% of the isolates and Intel II was present in 1.3% of the isolates. Intel I gene was detected in statistically significant high rate in MDR- P. aeruginosa [76.9%, P=0.001] compared to non MDR- P. aeruginosa [3.4%]. While, intel II had statistically insignificant increase in MDR- P. aeruginosa [1.1%, P=1.00] compared to non MDR-P. aeruginosa [1.7%]. Both Intl I/ Intl II genes were detected together in 2.2% of MDR- P. aeruginosa isolates and were absent in non MDR-P. aeruginosa isolates with statistically insignificant difference [P=1.00]. P. aeruginosa isolates with Intel I gene had increase in antibiotics resistance pattern to the used antibiotics discs, However, this increase had statistically significance rates only to gentamicin [63.9%, P≤0.001], meropenem [47.2%, P=0.009], trimethoprim/sulfamethoxazole [37.5%, P=0.013] and imipenem [44.4%, P=0.025].

CONCLUSION

The present study highlights the high prevalence of Intel I gene in clinical isolates of P. aeruginosa, while Intel II gene was less prevalent in these isolates. There was significant association between the prevalence of Intel I gene and MDR phenotype of P. aeruginosa and resistance to gentamicin, meropenem, trimethoprim/sulfamethoxazole and imipenem. These findings need future evaluation in higher number of clinical isolates of P. aeruginosa.

Characterization and genome analysis of a broad lytic spectrum bacteriophage P479 against multidrug-resistant Escherichia coli

The increase of multi-drug resistant and multi-serotypes of pathogenic Escherichia coli has brought more severe challenge to control infection. Nowadays, bacteriophage is a promising tool to treat colibacillosis as an alternative of antibiotics. A coliphage P479, isolated from sewage of poultry farm, could lyse multiple serotypes, including not only O1, O2, O8, O9, O21, O78, O83, O145 of Avian pathogenic E. coli, but O157:H7 of Enterohaemorrhagic E. coli and O18:K1:H7 Neonatal meningitis E. coli. Additionally, P479 could also lyse multi-drug resistant E. coli. These indicated that P479 had good lytic ability. One-step growth curve revealed that the latent time period of P479 was 10 min and the burst size was about 318 PFU/cell. Stability tests demonstrated that P479 had good stability under various temperature (4 to 50 °C) and pH (3 to11) conditions. P479 contained of a linear, double-stranded DNA molecule of 172,033 bp with 40.3% GC content. P479 contained 296 putative coding sequences (CDSs) and two tRNA genes. Based on genomic comparison, P479 was classified as a member of genus Gaprivervirus, subfamily Tevenvirinae, family Myoviridae, order Caudovirales. No known virulent or lysogenic genes were detected in the genome of P479, manifesting P479 was safe to adhibit. Antibacterial activity in vitro manifested that P479 has varying degrees bacteriostatic activity against different bacteria. According to the above properties, P479 has the potential to be applied in phage therapy in the future.

Bacteria from bovine clinical mastitis showed multiple drug resistance

Mastitis, which often manifests as udder infection in dairy animals, is of great concern as it affects public health and results in heavy economic losses to the dairy industry. A hospital-based cross-sectional study was conducted to determine the cultivable bacterial species associated with bovine clinical mastitis and their resistance patterns towards different antimicrobials. The milk samples from cows suffering from clinical mastitis during monsoon season were investigated. The prevalence of clinical mastitis was significantly high in Holstein-Friesian crossbred cows, followed by in Jersey crossbred, Red Kandhari and Deoni. Significantly high prevalence was observed during 4th to 6th months of lactation. A total of 110 bacterial isolates belonging to 14 different genera were isolated and identified. Aminoglycosides and quinolones were found to be the most effective antibiotics. Vancomycin resistant penicillinase producing Gram positive bacteria were demonstrated. Gram negative bacteria resistant to extended spectrum β lactamases, cephalosporins, tetracyclines, vancomycin and chloramphenicol as well as vancomycin resistant enterococci, multiple drug resistant (MDR) gram negative rods, MDR Pseudomonas and MDR Acinetobacter were found. Widespread resistance of Streptococcus uberis towards cephalosporins was documented. Variable MDR patterns were recorded within a single species. MDR transfer from non-pathogens to emerging foodborne and established mastitis pathogens could be a potential problem to the dairy industry as well as to public health.

Evaluation the effect of ZnO nanoparticle derived Bacillus subtilis on the expression of efflux pump genes (AdeB AdeRS) in Acinetobacter baumannii

PURPOSE

Green approach to the nanoparticles, including metal oxides due to inevitable disadvantages of physical or chemical synthesis routes is attractive nowadays. Zink oxide (ZnO) nanoparticles play a key role in the medical and pharmaceutical fields. This research aimed to study the biologically synthesized ZnO nanoparticle using Bacillus subtilis, and evaluated its antibacterial properties.

METHODS

Bacillus subtilis culture in a broth nutrient environment was used, followed by adding the Zinc acetate dehydrate. Biosynthesis of the nanoparticles was confirmed by the XRD, FTIR, and SEM imaging. The antibacterial effects of NPs on the expression of AdeB efflux pump genes and the AdeRS regulator were studied; clinical species of the Acinetobacter baumannii were collected from clinical samples of Khorramabad, using the phenotypic (MIC) and the genotypic methods through real-time PCR.

RESULTS

X-ray diffraction pattern (XRD) result showed, that all of the peaks were related to the ZnO, and no other peaks were detected; it also demonstrated nanostructure nature with crystallite size of 25-50 nm. The results indicated, that the antibacterial properties of the nanoparticle increased the AdeRS expression and decreased the AdeB expression in 40% of the A. Baumannii. In addition, there was an increase in the AdeB expression in 60% of the species, indicating an increased probability for mutation.

CONCLUSION

Given the desirable inhibitory effects of biosynthesized ZnO NPs on the expression of AdeB and AdeRS, which play an important role in the pharmaceutical resistance of Acinetobacter species, it seems that ZnO NPs can be used as a medication candidate in pharmaceutical industry in the future.

Establishment of drug-resistant cell lines under the treatment with chemicals acting through different mechanisms

The problem of chemoresistance development is an inescapable flipside of modern oncotherapy, in particular for сolorectal cancer patients. The search for or development of drugs effective against resistant tumors involves the use of model resistant cell lines in vitro. To obtain such lines, we reproduced the development of chemoresistance of human colon adenocarcinoma cells under the treatment with drugs of different mechanisms, a cytostatic (paclitaxel) and a targeted agent (Nutlin-3a, an inhibitor of p53-Mdm2 protein-protein interaction). In each case, we gradually increased the content of the substance in the medium, starting from effective concentrations that do not cause total cell death. When studying the lines resistant to the corresponding drug, we noted a reduced sensitivity to the drug of another mechanism of action. Analysis of the original and resistant lines showed that the cells use the universal efflux defense mechanism. The observed effect can be partially neutralized using inhibitors of the ABC transport proteins, including P-glycoprotein, known for its oncoprotective function. The role of the latter was confirmed by real-time RT-PCR and Western blotting.

Detection of MCR-1 Gene in Multiple Drug Resistant Escherichia coli and Klebsiella pneumoniae in Human Clinical Samples from Peshawar, Pakistan

BACKGROUND

The presence of plasmid mediated mcr-1 gene in multidrug resistant Gram-negative bacteria poses a serious public health concern in today's world.

OBJECTIVE

The present study was aimed to detect the presence of plasmid mediated mcr-1 encoding resistance to colistin in multiple drug resistant (MDR) E. coli and K. pneumoniae isolates.

METHODS

A total of 180 clinical isolates of E. coli (n=120) and K. pneumoniae (n=60) were isolated from different clinical specimens, i.e., urine, blood, stool and pus, from diagnostic labs of two major public sector tertiary care hospitals in Peshawar, Pakistan. MDR profile of these isolates was assessed through Kirby-Baur disc diffusion method. All isolates were screened for colistin resistance by dilution methods. Colistin resistant isolates were subjected to PCR for mcr-1 detection and confirmation was done by Sanger sequencing method.

RESULTS

Overall, 83.3% (100/120) E. coli and 93.3% (56/60) K. pneumoniae were detected as MDR. Colistin resistance was found in 23.3% (28/120) E. coli and 40% (24/60) K. pneumoniae isolates, whereas mcr-1 gene was detected in 10 out of 52 colistin resistant isolates, including six E. coli and four K. pneumoniae isolates. Minimum inhibitory concentrations (MICs) of colistin in these ten mcr-1 positive isolates ranged from 4μg/ml to 16μg/ml. All mcr-1 positive isolates showed 99% sequence similarity when compared with other present sequences in GenBank.

CONCLUSION

Hence, our study confirms the presence of mcr-1 mediated colistin resistance in the studied area. Therefore, urgently larger scale surveillance studies are recommended to investigate prevalence of mcr-1 mediated colistin resistance and to prevent its further spread in the area.

Molecular characteristics of drug-resistance Mycobacterium tuberculosis strains isolated from extra pulmonary tuberculosis sites

OBJECTIVES

China is the second high tuberculosis (TB) burden country in the world. This article was to determinate the molecular characteristic of drug resistance Mycobacterium tuberculosis (DRTB) strains from extra pulmonary tuberculosis (EPTB).

METHODS

The medical records of patients with EPTB were reviewed and collected from 2006 to 2016. The drug sensitivity of all samples was studied. All multiple drug resistance (MDR) and extensive drug resistance (XDR) strains were included. The detection of the deletion of region of difference 105 (RD105) and mycobacterial interspersed repetitive-unit variable-number tandem-repeat (MIRU-VNTR) were used to discriminate the molecular type of EPTB strains.

RESULTS

162 DRTB isolates were from patients with EPTB including 104 male and 58 female. Beijing genotype had a significant correlation with the patterns of DR (P<0.05), re-treatment patients (P<0.05) and gender (P<0.05). The history of treatment had a statistically significant correlation with patterns of DR (P<0.05) and gender (P<0.05). Patterns of DR had no correlation with gender (P>0.05). Of 162 strains Beijing family strains represented 91.4%. The cluster rate was 17.9% and clustering ratio was 11.1%. Beijing family genotype is predominant in the patients with EPTB. The cluster rate and clustering ratio was low.

CONCLUSIONS

Beijing family genotype is predominant and highly epidemic in the patients with drug resistance extra pulmonary tuberculosis (DR-EPTB). The cluster rate and clustering ratio was low. Genotype of re-treatment male patient with DR-EPTB is more likely Beijing family genotype.

Multi-drug resistance of Staphylococcus aureus Strains in Baqiyatallah hospital: a Primary Step Towards Digital Health Biomonitoring Systems

The aim of the study was to evaluate the drug-resistance patterns of Staphylococcus aureus infections in Baqiyatallah hospital within 2010–2019 and to present a novel monitoring and detection system making use of molecular laboratory methods teamed with molecular delimitation analyses. This in turn is a primary step to establishment of a digital health system within Baqiyatallah hospital as a perfect pilot instance for other hospitals to follow upon. Totally, 100 patients of Baqiyatallah hospital suspicious of Staphylococcus aureus infections were sampled. Bacterial identity confirmations were done using routine biochemical test. Antibiograms were made for all the patients in this study. Consequently, bacterial total DNA was extracted and 16S rDNA gene amplified and sequenced for all patients. To uncover any cryptic strain grouping within the samples, a molecular delimitation method, i.e. automated barcode gap discovery (ABGD), was done. Our results showed Ceftaroline to be the most and Erythromycin and Oxacillin the least effective drugs. Delimitation uncovered 19 groups out of which group 19 seemed to have location-specific genetic signals in regards to susceptibility of Erythromycin and Oxacillin. Our results indicate the importance of genetic identification of bacteria with respect to their genetic patterns before antibiotic administration in order to both reduce unnecessary medicine use and to biomonitor the bacterial patterns in respect to their behavior towards general antibiotics.

The APEX1/miRNA-27a-5p axis plays key roles in progression, metastasis and targeted chemotherapy of gastric cancer

Gastric cancer (GC) presents a challenge for conventional therapeutics due to low targeting specificity and subsequent elicitation of multiple drug resistance (MDR). As an essential enzyme for DNA repair, apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1) exhibits multiple functions to affect cancer malignancy and is excessively expressed in GC. However, the roles APEX1 and its inhibitor miR-27a-5p play in modulating GC progression and MDR development remains unclear. Here, we verified APEX1 as a target of miR-27a-5p and subsequently established the APEX1-deleted SGC-7901 cell line by CRISPR/Cas9 editing. The roles of the APEX1/miR-27a-5p axis in GC progression, metastasis and doxorubicin (DOX) resistance were explored by the targeted chemotherapy facilitated by a GC-specific peptide (GP5) functionalized liposomal drug delivery formulation (GP5/Lipo/DOX/miR-27a-5p). The results showed that APEX1 deletion distinctly attenuated cell growth and metastatic properties in GC, and also sensitized GC cells to DOX. Notably, miR-27a-5p was validated as a suppressor of APEX1-dependent GC development and DOX resistance by a RAS/MEK/FOS and PTEN/AKT/SMAD2 pathway-dependent manner. The altered expression of epithelial-mesenchymal transition (EMT) signatures and signal pathway proteins in the APEX1-deleted cells implied that APEX1 potentially enhances DOX resistance of GC cells by altering the regulation of MAPK and AKT pathways, leading to compromised efficacy of chemotherapy or by initiating additional DNA damage response pathways. Taken together, these findings revealed that as a novel therapeutic target, APEX1/miR-27a-5p axis plays essential roles in modulating the GC development and MDR, and the GC targeted drug delivery formulation presents a strategic reference for the future designation of chemotherapeutics study.

Multiple drug resistance bacterial isolates and associated factors among urinary stone patients at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia

BACKGROUND

The urinary stone and urinary tract infection (UTI) are invariably associated and are frequent causes of morbidity. Date on burden of UTI among urinary stone patients is lacking in Ethiopia. This study was aimed to assess bacterial profile, antimicrobial susceptibility and associated factors among urinary stone patients at the University of Gondar Comprehensive Specialized Hospital.

METHODS

An institution based cross sectional study was conducted. Basic sociodemographic data were collected using a structured questionnaire. Bacterial identification of uropathogens and drug susceptibility testing were done following standard microbiological techniques. The data were entered and analyzed using SPSS version-23. Bivariate and multivariate logistic regressions were used to identify possible associated risk factors. Results with P value < 0.05 was considered statistically significant.

RESULT

A total of 300 urinary stone patients were enrolled. Of these, 153 (51%) were male and 261(87%) were urban residents. The overall prevalence of urinary tract infection was 49 (16.3%) (95% CI 12-21%). A high level of resistance was observed to ampicillin, penicillin and trimethoprim-sulfamethoxazole while majority of isolates were most sensitive to nitrofurantoin and ciprofloxacin. Multi-drug resistant isolates were 16/49 (32.7%), 75% of them being Enterobacteriaceae isolates. More than one-third 9/26 (34.6%) of Gram-negative isolates were Extended Spectrum Beta-Lactamase (ESBL) producing E. coli and K. pneumoniae. Being female, history of urinary tract infection and history of drug use were the independent risk factors.

CONCLUSION

Most of the bacterial isolates from urinary stone patients were resistant to ampicillin, penicillin and trimethoprim-sulfamethoxazole. E. coli and K. pneumoniae were the most common extended spectrum beta-lactamase producing isolates. Sex, history of urinary tract infection and previous drug use were found to be risk factors. Routine diagnosis of urinary stone patients for urinary tract infection should be promoted and further researches are encouraged.

Biogenesis of silver nanoparticles to treat cancer, diabetes, and microbial infections: a mechanistic overview

Green synthesis of silver nanoparticles (SNPs) by harnessing the natural abilities of plant secondary metabolites has advantages over routine physical and chemical synthetic approaches due to their one-step experimental setup to reduce and stabilize the bulk silver into SNPs, biocompatible nature, and therapeutic significance. The unique size, shape, and biochemical functional corona of SNPs embellish them with the potential to perform therapeutic actions by adopting various mechanistic approaches including but not limited to the disruption of the electron transport chain, mitochondrial damage, DNA fragmentation, inhibition of ATP synthase activity, disorganization of the cell membrane, suspension of cellular signaling pathways, induction of apoptosis, and inhibition of enzymes activity. This review elaborates the biogenic synthesis of SNPs in redox chemical reactions by using plant secondary metabolites found in plant extracts. In addition, it explains the synergistic influence of physicochemical reaction parameters such as the temperature, pH, the concentration of the AgNO₃, and the ratio of reactants to affect the reaction kinetics, molecular mechanics, enzymatic catalysis, and protein conformations that aid to affect the size, shape, and potential biochemical corona of nanoparticles. This review also provides up-to-date information on the mechanistic actions that embellish the plant-based SNPs, an anticancer, cytotoxic, antidiabetic, antimicrobial, and antioxidant potential. The mechanistic understanding of the therapeutic actions of SNPs will help in precision medicine to develop customized treatment and healthcare approaches for the welfare of the human population. KEY POINTS: • Significance of the biogenic nanoparticles • Biomedical application potential of the plant-based silver nanoparticles • Mechanism of the anticancer, antidiabetic, and antimicrobial actions of the plant-based silver nanoparticles.

[Hospital hygiene 2.0 : Cross-interface, molecular epidemiological early warning systems for prevention of multidrug-resistant pathogens]

Infections caused by multidrug-resistant pathogens and their inpatient (nosocomial) and outpatient spread, pose increasing challenges to our healthcare system. Control strategies are derived from vertical (individual, pathogen-specific) and horizontal (general, pathogen-unspecific) preventive measures. The discussion of a competing "either or" has not proven to be effective in the past. In addition, the problem of multidrug-resistant pathogens cannot be solved solely in inpatient health care: the goals are a seamless communication and transparent cooperation between all actors in the healthcare system. Nowadays, modern molecular methods for pathogen typing are available, with the help of which transmission pathways can be clarified and hospital hygiene measures can be efficiently controlled. These procedures will be used increasingly more in the future to combat the problem of multidrug resistance across interfaces within regional network structures.

Sphingolipidomics of drug resistant Candida auris clinical isolates reveal distinct sphingolipid species signatures

Independent studies from our group and others have provided evidence that sphingolipids (SLs) influence the antimycotic susceptibility of Candida species. We analyzed the molecular SL signatures of drug-resistant clinical isolates of Candida auris, which have emerged as a global threat over the last decade. This included Indian hospital isolates of C. auris, which were either resistant to fluconazole (FLC^R) or amphotericin B (AmB^R) or both drugs. Relative to Candida glabrata and Candida albicans strains, these C. auris isolates were susceptible to SL pathway inhibitors such as myriocin and aureobasidin A, suggesting that SL content may influence azole and AmB susceptibilities. Our analysis of SLs confirmed the presence of 140 SL species within nine major SL classes, namely the sphingoid bases, Cer, αOH-Cer, dhCer, PCer, αOH-PCer, αOH-GlcCer, GlcCer, and IPC. Other than for αOH-GlcCer, most of the SLs were found at higher concentrations in FLC^R isolates as compared to the AmB^R isolates. SLs were at intermediate levels in FLC^R + AmB^R isolates. The observed diversity of molecular species of SL classes based on fatty acyl composition was further reflected in their distinct specific imprint, suggesting their influence in drug resistance. Together, the presented data improves our understanding of the dynamics of SL structures, their synthesis, and link to the drug resistance in C. auris.

•

Candida auris isolates are susceptible to sphingolipid inhibitors myriocin and aureobasidin A.

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The distribution of sphingolipid species is distinct among C. auris isolates resistant to different antifungals.

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Phytoceramides are the most abundant class of sphingolipid.

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Cer(d18:1/18:1) is the major of ceramide species in C. auris.

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d19:2 glucosylceramide backbone is typically in abundance in AmB resistant C. auris isolates.

Assessment of Susceptibility to Five Common Antibiotics and Their Resistance Pattern in Clinical Enterococcus Isolates

Background & Objective:

Enterococcus Species are the common cause of nosocomial infections, which are highly resistant to different antibiotics. Therefore, determination of their antibiotic susceptibility patterns and simultaneous resistance to antibiotics is important for better treatment strategies.

Methods:

400 clinical Enterococcus isolates were collected from different hospitals in Tehran, Iran. Standard phenotypic-biochemical tests and PCR were used to identify the Enterococcus species. The antimicrobial susceptibility patterns and simultaneous resistance to selected antibiotics were determined by disk diffusion method according to the CLSI guidelines. All data analysis was performed using Python packages Scipy and Stats models.

Results:

According to the biochemical and PCR analyses, among 400 Enterococcus species, 72% of samples were Enterococcus faecalis, 10.75% Enterococcus faecium, and 17.25% other Enterococcus species. The results determined antimicrobial resistances of these strains against gentamicin, vancomycin, fosfomycin trometamol, teicoplanin, and quinupristin/dalfopristin. Results confirmed a significant correlation between resistance to vancomycin and resistance to teicoplanin. This correlation remains significant when including only E. faecium or E. faecalis species. We also found a negative correlation between resistance to teicoplanin and quinupristin/dalfopristin. Additionally, Quinupristin/dalfopristin was the least effective antibiotic while vancomycin and teicoplanin were the most effective ones.

Conclusion:

Based on the results and association between simultaneous resistance to some antibiotics such as vancomycin and teicoplanin, in the case of antibiotic resistance, the choice of a second antibiotic can be very important which can lead to good or bad effects.

Comprehensive evaluation of chitosan nanoparticle based phage lysin delivery system; a novel approach to counter S. pneumoniae infections

Cpl-1, an endolysin derived from Cp-1 phage has been found to be effective in a number of in-vitro and in-vivo pneumococcal infection models. However its lower bioavailability under in-vivo conditions limits its applicability as therapeutic agent. In this study, Cpl-1 loaded chitosan nanoparticles were set up in order to develop a novel therapeutic delivery system to counter antibiotic resistant S. pneumoniae infections. Interactions of chitosan and Cpl-1 were studied by in-silico docking analysis. Chitosan nanoparticles and Cpl-1 loaded chitosan nanoparticles were prepared by using ionic gelation method and the process was optimized by varying chitosan:TPP ratio, pH, stirring time, stirring rate and Cpl-1 concentration. Chitosan nanoparticles and Cpl-1 loaded chitosan nanoparticles were characterized to ascertain successful formation of nanoparticles and entrapment of Cpl-1 into nanoparticles. Chitosan nanoparticles and Cpl-1 loaded nanoparticles were also evaluated for nanoparticle yield, entrapment efficiency, in-vitro release, stability, structural integrity of Cpl-1, in-vitro bioassay, swelling studies, in-vitro biodegradation and heamolysis studies. Mucoadhesion behavior of chitosan nanoparticles and Cpl-1 loaded nanoparticles was explored using mucous glycoprotein assay and ex-vivo mucoadhesion assay, both preparations exhibited their mucoadhesive nature. Cellular cytotoxicity and immune stimulation studies revealed biocompatible nature of nanoparticles. The results of this study confirm that chitosan nanoparticles are a promising biocompatible candidate for Cpl-1 delivery with a significant potential to increase bioavailability of enzyme that in turn can increase its in-vivo half life to treat S. pneumoniae infections.

Association between carbapenem-resistant Enterobacteriaceae and death: A systematic review and meta-analysis

BACKGROUND

Carbapenem-resistant Enterobacteriaceae (CRE) has emerged in health care facilities around the world. Several studies demonstrated data regarding clinical outcomes for CRE infections including death. This systematic review and meta-analysis summarized literature discussing association between CRE and mortality.

METHODS

A systematic literature review was performed by searching EMBASE, International Pharmaceutical Abstract databases, PubMed, and Scopus and to identify studies that assessed the association between CRE and death published from April 2012 to October 2017. A meta-analysis was performed using a random effect model. Heterogeneity was assessed using the I²-statistic.

RESULTS

Twenty-one studies were included in this meta-analysis. The underlying populations were moderately heterogeneous (I² = 60%; P = .01). Pooled risk estimates from 9 studies revealed a significant association between CRE and death (pooled-adjusted odds ratio: 2.85; 95% confidence interval: 1.88, 4.30). The unadjusted variable pooled from 18 studies demonstrated a significant association between CRE and death (pooled-unadjusted odds ratio: 3.73; 95% confidence interval: 2.02, 6.88).

DISCUSSION

The finding that CRE infection was positively associated with death agreed with the previous meta-analysis of studies published before April 2012.

CONCLUSIONS

This meta-analysis found that CRE was associated with increased risk of death. Our analysis implies a need for strict infection control measures.

Reversal effect of FW-04-806, a macrolide dilactone compound, on multidrug resistance mediated by ABCB1 and ABCG2 in vitro and in vivo

Background

Overexpression of ATP-binding cassette (ABC) transporters, such as ABCB1 and ABCG2, has been proved to be a major trigger for multidrug resistance (MDR) in certain types of cancer. A promising approach to reverse MDR is the combined use of nontoxic and potent ABC transporters inhibitor with conventional anticancer drugs. We previously reported that FW-04-806 (conglobatin) as a novel Hsp90 inhibitor with low toxicity, capable of attenuating Hsp90/Cdc37 /clients interactions and producing antitumor action in vitro and in vivo. Our early activity screening found that FW-04-806 at non-cytotoxic concentration was able to enhance the cytotoxicity of chemotherapeutic agents on the ABCB1 overexpressing cells. Therefore, we speculated that FW-04-806 might be a promising MDR reversal agent. In the present study we further investigated its reversal effect of MDR induced by ABC transporters in vitro and in vivo.

Methods

MTT assay in vitro and xenograftes in vivo were used to investigate reversal effect of FW-04-806 on MDR in ABCB1 or ABCG2 overexpressing cancer cells. To understand the mechanisms for the MDR reversal, we examined the effects of FW-04-806 on intracellular accumulation of doxorubicin (DOX, adriamycin, adr)/Rhodamine 123 (Rho 123), efflux of doxorubicin, expression levels of gene and protein of ABCB1 or ABCG2 and ATPase activity of ABCB1, and carried out molecular docking between FW-04-806 and human ABCB1.

Results

The results indicated that FW-04-806 significantly enhanced the cytotoxicity of substrate chemotherapeutic agents on the ABCB1 or ABCG2 overexpressing cells in vitro and in vivo suggesting its reversal MDR effects. FW-04-806 increased the intracellular accumulation of DOX or Rho123 by inhibiting the efflux function of ABC transporters in MDR cells rather than in their parental sensitive cells. However, unlike other ABC transporter inhibitors, FW-04-806 had no effect on the ATPase activity nor on the expression of ABCB1 or ABCG2 on either mRNA or protein level. Molecular docking suggested that FW-04-806 may have lower affinity to the ATPase site, which was consistent with its no significant effect on the ATPase activity of ABCB1; However FW-04-806 may bind to substrate binding site in TMDs more stably than substrate anticancer drugs therefore obstruct the anticancer drugs pumped out of the cell.

Conclusions

FW-04-806 is a compound that has both anti-tumor and reversal MDR effects, and its antitumor clinical application is worth further study.

Graphical abstract

Microfluidic device for the analysis of MDR cancerous cell-derived exosomes' response to nanotherapy

Exosomes are membrane-enclosed extracellular vesicles which have been indicated as important biomarkers of cancerous cell functionality, such as multiple drug resistance (MDR). Nanoparticles based chemotherapy is a promising strategy to overcome MDR by interfering the production and composition of exosomes. Therefore, tumor-derived exosomes post-treatment by nanotherapy are implied to play critical roles of biomarkers on cancer MDR analysis. However, the efficient isolation of such exosomes from extracellular environment for their therapeutic response analysis remains challenging. In this study, we presented a microfluidic device featured exosome specific anti-CD63 immobilized ciliated micropillars, which were capable to isolate cancer-derived exosomes from cell culture medium. The captured exosomes can be recovered intact by dissolving the cilia on the micropillars using PBS soaking. Owing to the immobilized antibody in the microfluidic device, nearly 70% of exosome from the biofluid could be isolated. So the secreted exosomes of the MDR and ordinary human breast cancer cells pre-treated by free drug or nanotherapy could be isolated with high purity. The drug contents of the isolated exosomes were measured to analysis of the exosomal pathway response of MDR cells to different chemotherapeutic formulations. Such analyses and further definition of the biomarkers of these exosomes could benefit the future investigations of accurately and reliably determine design principle, functional activity, and mechanisms of nanotherapy for MDR overcoming.

Effects of the timing of administration of IgM- and IgA-enriched intravenous polyclonal immunoglobulins on the outcome of septic shock patients

BACKGROUND

The administration of endovenous immunoglobulins in patients with septic shock could be beneficial and preparations enriched with IgA and IgM (ivIgGAM) seem to be more effective than those containing only IgG. In a previous study Berlot et al. demonstrated that early administration of ivIgGAM was associated with lower mortality rate. We studied a larger population of similar patients aiming either to confirm or not this finding considering also the subgroup of patients with septic shock by multidrug-resistant (MDR) pathogens.

METHODS

Adult patients with septic shock in intensive care unit (ICU) treated with ivIgGAM from August 1999 to December 2016 were retrospectively examined. Collected data included the demographic characteristics of the patients, the diagnosis at admission, SOFA, SAPS II and Murray Lung Injury Score (LIS), characteristics of the primary infection, the adequacy of antimicrobial therapy, the delay of administration of ivIgGAM from the ICU admission and the outcome at the ICU discharge. Parametric and nonparametric tests and logistic regression were used for statistic analysis.

RESULTS

During the study period 107 (30%) of the 355 patients died in ICU. Survivors received the ivIgGAM earlier than nonsurvivors (median delay 12 vs 14 h), had significantly lower SAPS II, SOFA and LIS at admission and a lower rate of MDR- and fungal-related septic shock. The appropriateness of the administration of antibiotics was similar in survivors and nonsurvivors (84 vs 79%, respectively, p: n.s). The delay in the administration of ivIgGAM from the admission was associated with in-ICU mortality (odds ratio per 1-h increase = 1.0055, 95% CI 1.003-1.009, p < 0.001), independently of SAPS II, LIS, cultures positive for MDR pathogens or fungi and onset of septic shock. Only 46 patients (14%) had septic shock due to MDR pathogens; 21 of them (46%) died in ICU. Survivors had significantly lower SAPS II, SOFA at admission and delay in administration of ivIgGAM than nonsurvivors (median delay 18 vs 66 h). Even in this subgroup the delay in the administration of ivIgGAM from the admission was associated with an increased risk of in-ICU mortality (odds ratio 1.007, 95% CI 1.0006-1.014, p = 0.048), independently of SAPS II.

CONCLUSIONS

Earlier administration of ivIgGAM was associated with decreased risk of in-ICU mortality both in patients with septic shock caused by any pathogens and in patients with MDR-related septic shock.

Early Detection and Analysis of Children with Multidrug-Resistant Tuberculosis of the Spine

Study Design

Retrospective case series.

Purpose

The aim of the study is to report the clinical characteristics, early diagnosis, management, and outcome of children with multidrug-resistant (MDR) tubercular spondylodiscitis and to assess the early detection of rifampicin resistance using the Xpert MTB/ RIF assay.

Overview of Literature

MDR tuberculosis is on the rise, especially in developing countries. The incidence rate of MDR has been reported as 8.9% in children.

Methods

A retrospective study of children aged <15 years of age who were diagnosed and treated for MDR tuberculosis of the spine was conducted. Confirmed cases of MDR tuberculosis and patients who had completed at least 18 months of second-line antituberculous treatment (ATT) were included. Children were treated with ATT for 24 months according to drug-susceptibility-test results. Outcome measures included both clinical and radiological measures. Clinical measures included pain, neurological status, and return to school. Radiological measures included kyphosis correction and healing status.

Results

Six children with a mean age of 10 years were enrolled. The mean follow-up period was 12 months. All the children had previous history of treatment with first-line ATT, with an average of 13.6 months before presentation. Clinically, 50% (3/6 children) had psoas abscesses and 50% had spinal deformities. Radiologically, 50% (three of six children) had multicentric involvement. Three children underwent surgical decompression; two needed posterior stabilization with pedicle screws posteriorly followed by anterior column reconstruction. Early diagnosis of MDR was achieved in 83.3% (five of six children) with Xpert MTB/RIF assay. A total of 83.3% of the children were cured of the disease.

Conclusions

Xpert MTB/RIF assay confers the advantage of early detection, with initiation of MDR drugs within an average of 10.5 days from presentation. The cost of second-line ATT drugs was 30 times higher than that of first-line ATT.

Hsa-miRNA-143-3p Reverses Multidrug Resistance of Triple-Negative Breast Cancer by Inhibiting the Expression of Its Target Protein Cytokine-Induced Apoptosis Inhibitor 1 In Vivo

PURPOSE

Multidrug resistance (MDR) remains a major obstacle in the treatment of triple-negative breast cancer (TNBC) with conventional chemotherapeutic agents. A previous study demonstrated that hsa-miRNA-143-3p plays a vital role in drug resistance of TNBC. Downregulation of hsa-miRNA-143-3p upregulated the expression of its target protein cytokine-induced apoptosis inhibitor 1 (CIAPIN1) in order to activate MDR, while upregulation of hsa-miRNA-143-3p effectively enhances the sensitivity of drug-resistant TNBC cells to chemotherapeutics. The present study aimed to further verify these findings in vivo.

METHODS

We established a hypodermic tumor nude mice model using paclitaxel-resistant TNBC cells. We expressed ectopic hsa-miRNA-143-3p under the control of a breast cancer-specific human mammaglobin promoter that guided the efficient expression of exogenous hsa-miRNA-143-3p only in breast cancer cells. Thereafter, we overexpressed hsa-miRNA-143-3p in xenografts using a recombinant virus system and quantified the expression of hsa-miRNA-143-3p, CIAPIN1 protein, and proteins encoded by related functional genes by western blot.

RESULTS

We successfully completed the prospective exploration of the intravenous virus injection pattern from extensive expression to targeted expression. The overexpression of hsa-miRNA-143-3p significantly alleviated chemoresistance of TNBC by inhibiting viability. In addition, we observed that the expression of CIAPIN1 as a hsa-miRNA-143-3p target protein was remarkably decreased.

CONCLUSION

We partly illustrated the mechanism underlying the hsa-miRNA-143-3p/CIAPIN1 drug resistance pathway. HsamiRNA-143-3p as a tumor suppressive microRNA may be a novel target to effectively reverse MDR of TNBC in vivo.

Neoadjuvant Endocrine Therapy in Breast Cancer Upregulates the Cytotoxic Drug Pump ABCG2/BCRP, and May Lead to Resistance to Subsequent Chemotherapy

INTRODUCTION

Neoadjuvant treatments for primary breast cancer are becoming more common; however, little is known about how these impact on response to subsequent adjuvant therapies. Conveniently, neoadjuvant therapy provides opportunities to consider this question, by studying therapy-induced expression changes using comparisons between pre- and posttreatment samples. These data are relatively lacking in the context of neoadjuvant endocrine therapy, as opposed to the more common neoadjuvant chemotherapy. Here, we investigate the relevance of expression of the xenobiotic transporter ABCG2/BCRP, a gene/protein associated with chemoresistance, in the context of neoadjuvant endocrine therapy and particularly with reference to subsequent chemotherapy treatment.

MATERIALS AND METHODS

ABCG2/BCRP expression was assessed by immunohistochemistry or by expression arrays in matched patient samples pre- and post-neoadjuvant endocrine therapy. Cell culture was used to model the impact of endocrine therapy-induced changes in ABCG2/BCRP on subsequent chemotherapy response, using Western blots, quantitative polymerase chain reaction, survival assays, and cell cycle analyses.

RESULTS

ABCG2/BCRP was commonly and significantly upregulated in breast cancers after treatment with neoadjuvant endocrine therapy in 3 separate cohorts encompassing a total of 200 patients. Treatment with the endocrine therapeutic tamoxifen similarly induced ABCG2/BCRP upregulation in a relevant model cell line, the estrogen receptor-positive line T47D. Critically, this upregulation was associated with significantly increased chemoresistance to subsequent treatment with epirubicin, an anthracycline commonly used in breast cancer adjuvant chemotherapy.

CONCLUSION

Our data suggest that neoadjuvant endocrine therapy may induce poor responses to adjuvant chemotherapy, and therefore, that clinical outcomes following this treatment sequence warrant further study.

Biglycan promotes the chemotherapy resistance of colon cancer by activating NF-κB signal transduction

Biglycan (BGN) is overexpressed in cancer stem cells of colon cancer and induces the activation of NF-κB pathway which contributes to the chemotherapy resistance of diverse cancer types. Therefore, we hypothesized that the overexpression of BGN also promoted the development of multiple drug resistance (MDR) in colon cancer via NF-κB pathway. The expression of BGN was bilaterally modulated in colon cancer cell lines HT-29 and SW-480 and the effect of treatments on the cell proliferation and resistance to 5-FU was assessed. Moreover, the role of NF-κB signaling in the BGN-mediated formation of MDR was further investigated by subjecting BGN-overexpressed SW-480 cells to the co-treatment of chemo-agents and NF-κB inhibitor, PDTC. The inhibition of BGN expression decreased the proliferation potential of HT-29 cells while the induction of BGN expression increased the potential of SW-480 cells. BGN knockdown increased HT-29 cells' sensitivity to 5-FU, represented by the lower colony number and higher apoptotic rate. To the contrary, BGN overexpression promoted the resistance of SW-480 cells to 5-FU. The effect of BGN modulation on colon cancer cells was associated with the changes in apoptosis and NF-κB pathways: BGN inhibition increased the expressions of pro-apoptosis indicators and suppressed NF-κB pathway activity while BGN overexpression had the opposite effect. It was also found that the BGN-mediated formation of MDR was impaired when NF-κB pathway was blocked. Findings outlined in the current study showed that BGN contributed to the formation of chemotherapy resistance in colon cancer cells by activating NF-κB signaling.

ARID1A ablation leads to multiple drug resistance in ovarian cancer via transcriptional activation of MRP2

Multiple Drug Resistance (MDR) of ovarian cancer is a severe trouble for clinical treatment and always contributes to a bad prognosis. AT-rich interaction domain 1 A (ARID1A) has been recognized as a bona fide tumor suppressor gene in recent years, with the highest mutation rate in ovarian cancer. Previous study illustrated that ARID1A expression is negatively correlated with chemoresistance of ovarian cancer cases. However, the specific role of ARID1A in chemoresistance of ovarian cancer remains elusive. In this study, we showed that ARID1A knockdown in ovarian cancer cells significantly reduced their apoptosis rate and led to MDR, while ectopic expression of ARID1A showed opposite effects. ARID1A depletion transcriptionally activates the expression of multidrug resistance-associated protein 2 (MRP2) following chromatin remodeling. Furthermore, IHC analysis of ovarian cancer samples confirmed that ARID1A expression was strong negatively correlated with MRP2 expression. Both ARID1A and MRP2 expression levels are correlated with sensitivity to platinum. Collectively, our results illustrated that ARID1A loss in ovarian cancer leads to MDR through upregulation of MRP2, providing an opportunity to overcome the ARID1A loss induced chemoresistance of ovarian cancer by targeting MRP2.

N-desmethyl tamoxifen and quercetin-loaded multiwalled CNTs: A synergistic approach to overcome MDR in cancer cells

Our aim was to develop multiwalled carbon nanotubes (MWCNTs)-based nanoconstructs for the codelivery of N-desmethyl tamoxifen (N-TAM) and a mild P-gp efflux inhibitor, i.e., quercetin (QT) to treat multiple drug resistant (MDR) cancer cells. The hypothesis banks on three-tier attack on the MDR mechanisms viz. drug derivatization, MWCNT permeation and P-gp inhibition. Tamoxifen was converted to N-TAM and was conjugated to carboxylated MWCNTs mediated by a biodegradable linker, i.e., tetraethylene glycol (TEG). QT was adsorbed on the conjugate to fetch the final product, i.e., N-TAM-TEG-MWCNT-QT. Spectroscopic analysis confirmed successful conjugation of N-TAM and physical adsorption of QT. The in-vitro release of N-TAM from the N-TAM-TEG-MWCNT conjugate was minimal to that of pure drug under physiological conditions, but markedly enhanced under the acidic pH of cancer cells. The developed nanometeric formulation was found to be haemo-compatible. Reduced IC₅₀values and better cellular uptake in drug resistant MDA-MB-231 cells were observed, followed by enhanced drug availability in the systemic circulation of rodents vis-à-vis naïve drug. The smart nanosystem conferred the desired temporal drug delivery, enhanced drug efficacy, biocompatibility and conducive pharmacokinetics, which are the crucial desired attributes to tackle the increasing concern of MDR in cancer chemotherapy.

Multiple drug resistance and biocide resistance in Escherichia coli environmental isolates from hospital and household settings

Background

Antibiotic resistance of environmental Escherichia coli in hospitals could be increased due to extensive use of biocides resulting in serious infections. In this study, the prevalence of antibiotic resistance of environmental isolates of E. coli from hospitals and household settings were evaluated and compared. In addition, the association between biocide minimum inhibitory concentration (MIC) and multiple drug resistance (MDR) was investigated.

Methods

Environmental samples were collected from different homes and hospitals in Amman, Jordan. The isolates were identified phenotypically and by PCR. Antibiotic susceptibility tests and MIC of selected biocides were performed on the isolates. Screening for blaCTX-M group 1 was also performed.

Results

Of 21 E. coli strains isolated, 47.6% were MDR and 67.9% were phenotypically identified as extended spectrum beta-lactamase (ESBL) producers. The occurrence of these ESBL isolates was comparable between household and hospital settings (P > 0.05). The MIC values of the biocides tested against all isolates were well below the in-use concentration of biocides. Moreover, the MICs of biocides were comparable between isolates from households and those from hospitals (P > 0.05). No association was found between MDR and biocide MIC (P > 0.05). Most of ESBL isolates harboured blaCTX-M 1.

Conclusions

The extensive use of biocides in hospitals is not associated with MDR nor does it affect the MIC of biocides against E.coli.

Reversal effect of quercetin on multidrug resistance via FZD7/β-catenin pathway in hepatocellular carcinoma cells

BACKGROUND

Chemotherapy has been widely used to treat cancer, but the appearance of multidrug resistance (MDR) is the biggest obstacle to successful chemotherapy. One of the conventional mechanisms of MDR is overexpression of ATP-binding cassette (ABC) transporters such as P-glycoprotein (P-gp/ABCB1) and multidrug resistance-associated proteins (MRPs/ABCCs) that limits the prolonged and efficient use of chemotherapeutic drugs. To enhance the chemosensitivity of tumor cells, attentions have been focused on effective MDR modulators.

PURPOSE

This study aimed to investigate the reversal effect of quercetin on MDR, and explored its mechanism of action in vitro.

STUDY DESIGN/METHODS

The effect and mechanism of quercetin on MDR was examined by using MTT assay, flow cytometry, real-time PCR and western blot analysis in human hepatocellular carcinoma cells.

RESULTS

Our data found that the intracellular accumulation of rhodamine-123 (Rh123) and doxorubicin (ADR) were increased, the sensitivity of BEL/5-FU cells to chemotherapeutic drugs were increased, and the expressions of ABCB1, ABCC1 and ABCC2 were all down-regulated, which indicated that the functions and expressions of ABCB1, ABCC1 and ABCC2 efflux pump were inhibited by quercetin treatment. Moreover, the suppression of ABCB1, ABCC1 and ABCC2 by quercetin was dependent on the FZD7 through the Wnt/β-catenin pathway. Further research revealed that reduction of FZD7 by RNA interference (siFZD7) enhanced the sensitivity to chemotherapeutic drugs, increased the cellular accumulation of Rh123 and ADR, and induced inhibitory effects on the expression of FZD7, ABCB1, ABCC1, ABCC2 and β-catenin, similar to quercetin. In the meanwhile, overexpression of FZD7 showed the inversely effect on the expressions. Interesting, it was confirmed that quercetin could inhibit the expression levels of FZD7, ABCB1, ABCC1, ABCC2 and β-catenin in BEL-7402 cells; furthermore, treatment by quercetin combined with siFZD7 in BEL/5-FU cells, the expressions of these genes were effectively decreased in comparison to quercetin combined with siRNA negative control (sncRNA).

CONCLUSION

Overall, these data suggested the effectiveness of using quercetin, at least in part, via inhibiting FZD7 to combat chemoresistance and showed that quercetin could be developed into an efficient natural sensitizer for resistant human hepatocellular carcinoma.

Tyrosine kinase inhibitors enhanced the efficacy of conventional chemotherapeutic agent in multidrug resistant cancer cells

Multidrug resistance (MDR) triggered by ATP binding cassette (ABC) transporter such as ABCB1, ABCC1, ABCG2 limited successful cancer chemotherapy. Unfortunately, no commercial available MDR modulator approved by FDA was used in clinic. Tyrosine kinase inhibitors (TKIs) have been administrated to fight against cancer for decades. Almost TKI was used alone in clinic. However, drug combinations acting synergistically to kill cancer cells have become increasingly important in cancer chemotherapy as an approach for the recurrent resistant disease. Here, we summarize the effect of TKIs on enhancing the efficacy of conventional chemotherapeutic drug in ABC transporter-mediated MDR cancer cells, which encourage to further discuss and study in clinic.

Novel Doxorubicin Derivatives: Synthesis and Cytotoxicity Study in 2D and 3D in Vitro Models

Purpose: Multidrug resistance (MDR) of tumors to chemotherapeutics often leads to failure of cancer treatment. The aim of the study was to prepare novel MDR-overcoming chemotherapeutics based on doxorubicin (DOX) derivatives and to evaluate their efficacy in 2D and 3D in vitro models. Methods: To overcome MDR, we synthesized five DOX derivatives, and then obtained non-covalent complexes with human serum albumin (HSA). Drug efficacy was evaluated for two tumor cell lines, namely human breast adenocarcinoma MCF-7 cells and DOX resistant MCF-7/ADR cells. Additionally, MCF-7 cells were entrapped in alginate-oligochitosan microcapsules, and generated tumor spheroids were used as a 3D in vitro model to study cytotoxicity of the DOX derivatives. Results: Due to 3D structure, the tumor spheroids were more resistant to chemotherapy compared to monolayer culture. DOX covalently attached to palmitic acid through hydrazone linkage (DOX-N2H-Palm conjugate) was found to be the most promising derivative. Its accumulation levels within MCF-7/ADR cells was 4- and 10-fold higher than those of native DOX when the conjugate was added to cultivation medium without serum and to medium supplemented with 10% fetal bovine serum, respectively. Non-covalent complex of the conjugate with HSA was found to reduce the IC50 value from 32.9 µM (for free DOX-N2H-Palm) to 16.8 µM (for HSA-DOX-N2H-Palm) after 72 h incubation with MCF-7/ADR cells. Conclusion: Palm-N2H-DOX conjugate was found to be the most promising DOX derivative in this research. The formation of non-covalent complex of Palm-N2H-DOX conjugate with HSA allowed improving its anti-proliferative activity against both MCF-7 and MCF-7/ADR cells.

Molecular characterization of β-lactamase genes in clinical isolates of carbapenem-resistant Acinetobacter baumannii

Background

Acinetobacter baumannii is a nosocomial pathogen which is establishing as a major cause of morbidity and mortality within the healthcare community. The success of this pathogen is largely due to its ability to rapidly gain resistance to antimicrobial therapies and its capability to persist in an abiotic environment through the production of a biofilm. Our tertiary-care hospital has showed high incidence of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates.

Methods

In this study we explore both genotypic and phenotypic properties of 26 CRAB isolates: 16 isolates were collected from January 2010 to March 2011, and 10 were collected between February and May 2015.

Results

We determined that all 26 CRAB isolates possessed multiple β-lactamase genes, including genes from Groups A, C, and D. Specifically, 42% of the isolates possesses the potentially plasmid-borne genes of OXA-23-like or OXA-40-like β-lactamase. The presence of mobile gene element integron cassettes and/or integrases in 88% of the isolates suggests a possible mechanism of dissemination of antibiotic resistance genes. Additionally, the location of insertion sequence (IS) ISAba1 in promotor region of of the OXA-51-like, ADC-7, and ampC genes was confirmed. Multilocus sequence typing (MLST) demonstrated that all 26 CRAB isolates were either sequence type (ST)-229 or ST-2. Interestingly, ST-2 went from being the minority CRAB strain in the 2010–2011 isolates to the predominant strain in the 2015 isolates (from 32 to 90%). We show that the ST-2 strains have an enhanced ability to produce biofilms in comparison to the ST-229 strains, and this fact has potentially led to more successful colonization of the clinical environment over time.

Conclusions

This study provides a longitudinal genetic and phenotypic survey of two CRAB sequence types, and suggests how their differing phenotypes may interact with the selective pressures of a hospital setting effecting strain dominance over a 5-year period.

Electronic supplementary material

The online version of this article (10.1186/s12941-017-0248-3) contains supplementary material, which is available to authorized users.

Colonization, resistance to bile, and virulence properties of Escherichia coli strains: Unusual characteristics associated with biliary tract diseases

Escherichia coli is the species that is most frequently isolated from bile of patients with biliary tract diseases. This study was aimed to investigate any association between resistance and virulence properties of these isolates with occurrence of the diseases. A total of 102 bile samples were obtained from patients subjected to endoscopic retrograde cholangiopancreatography for different biliary diseases. Clinical data were collected and culture of the bile samples was done on selective media. Resistance of characterized Escherichia coli isolates to deoxycholate sodium (0-7%) and nineteen antibiotics was determined and PCR using 16 pairs of primers targeting stx1, stx2, exhA, eae, bfp, agg, pcvd432, lt, st, ipaH, pic, pet, ast, set, sen, and cdtB genes was done. Our results showed a statistically significant association between E. coli colonization and existence of common bile duct and gallbladder stones (p value 0.028). Out of the 22 E. coli strains (22/102) multidrug resistance phenotype was present in 95.45%. None of the strains belonged to common E. coli pathotypes. However, bfp + EhxA-hly, bfp + astA, bfp + EhxA-hly + pic, and EhxA-hly + pic + astA, bfp, and astA genotypes were detected in these strains. bfp (7/22, 31.8%) and astA (5/22, 22.7%) were among most frequent virulence factors in these strains. Results of this study showed significant association between colonization of E. coli and choledocholithiasis. Unusual existence of virulence gene combinations in these strains and their resistance to DOC and multiple classes of antibiotics could be considered as possible causes of their persistence in this harsh microenvironment.

Revisiting Nitrofurantoin for Vancomycin Resistant Enterococci

INTRODUCTION

Enterococcal infection has emerged as a major therapeutic challenge. Emergence of High Level Aminoglycoside Resistance (HLAR) and Vancomycin-Resistant Enterococcus (VRE) has further limited the drug therapy in enterococcal infections. However, nitrofuratoin being an old drug reported to have less resistance in comparison to the other classes of antimicrobial agents.

AIM

To detect susceptibility of nitrofurantoin against VRE isolates from Urinary Tract Infection (UTI) of outdoor and indoor patient departments.

MATERIALS AND METHODS

An observational study was carried out at a tertiary care hospital in New Delhi over a period of six months (from November 2015 to April 2016). A total of 14,714 urine samples were collected and processed from the patients symptomatic for UTI. The enterococcal isolates were identified and confirmed by standard phenotypic tests. The antimicrobial susceptibility tests of isolated organisms were performed by Kirby-Bauer Disc Diffusion Method as per Clinical and Laboratory Standards Institute (CLSI) 2015 guidelines. The Wilcoxon rank-sum (Mann-Whitney) test was used to compare continuous variables. Chi-square or Fisher's exact tests were used to compare categorical variables. p<0.05 was considered as significant.

RESULTS

A total of 70 enterococci species {Enterococcus faecalis (n=9), Enterococcus faecium, (n=61)} were isolated. Twenty six out of 70 isolates were observed resistant to vancomycin. Among 26 VRE, 21(80.76%) were susceptible to nitrofurantoin. Both the species {E. faecalis (80.32%) and E. faecium (88.8%)} were uniformly susceptible to nitrofurantoin.

CONCLUSION

Nitrofurantoin has retained antimicrobial efficacy against emerging VRE in vitro and can be used for treatment of enterococcal urinary tract infections.

MiR-466b-1-3p regulates P-glycoprotein expression in rat cerebral microvascular endothelial cells

Epilepsy is one of the most common neurological disorders, and approximately one-third of epilepsy cases are resistant to treatment with anti-epileptic drug (AED). P-glycoprotein (P-gp) is a multi-drug transporter that is thought to play a pivotal role in multiple drug resistance (MDR) in epilepsy. The regulatory mechanism of P-gp remains largely unknown; however, recent studies have demonstrated that microRNAs (miRNAs) may regulate the chemo-resistance mediated by P-gp. This study investigated the effect of specific miRNAs that regulate P-gp expression in rat cerebral microvascular endothelial cells (RCMECs). Primary cultures of RCMECs were treated with phenobarbital (PB) at various concentrations to induce P-gp overexpression. MiRNA microarrays were used to investigate the expression profiles of miRNAs in the resistant RCMECs induced by PB and corresponding non-resistant cells. Our data demonstrated decreased miR-466b-1-3p expression in the resistant cells compared with the non-resistant cells. Moreover, the recombinant RNA of 466b-1-3p (mimic) and the artificial antisense RNA of miR-466b-1-3p (inhibitor) were constructed and transfected into resistant RCMECs. The expression and function of P-gp were measured by Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR) and flow cytometry using rhodamine efflux. The mRNA and protein levels of P-gp increased as the concentration of PB increased, whereas miR-466b-1-3p levels decreased with increasing PB concentrations (P<0.05). The miR-466b-1-3p mimic down-regulated P-gp expression, whereas the miR-466b-1-3p inhibitor up-regulated P-gp expression (P<0.05). These findings demonstrate that miR-466b-1-3p may regulate PB-induced P-gp expression in RCMECs.

Developing piperlongumine-directed glutathione S-transferase inhibitors by an electrophilicity-based strategy

We report a case of successful design of glutathione S-transferase (GST) inhibitors via a natural product-inspired and electrophilicity-based strategy. Based on this strategy, a novel piperlongumine analog (PL-13) bearing a para-trifluoromethyl group and an α-chlorine on its aromatic and lactam rings, respectively, surfaced as a promising GST inhibitor, thereby overcoming cisplatin resistance in lung cancer A549 cells.

Prospective study analyzing risk factors and characteristics of healthcare-associated infections in a Urology ward

PURPOSE

Healthcare-associated infections (HAIs) in urological patients have special features due to specific risk factors. Our objective was to evaluate the characteristics and risk factors for HAIs in patients hospitalized in a Urology ward.

MATERIALS AND METHODS

We evaluated prospectively, from 2012 to 2015, the incidence, types and risk factor for HAIs, microbiological and resistance patterns.

RESULTS

The incidence of HAIs was 6.3%. The most common types were urinary infections (70.5%) and surgical site infections (22.1%). Univariate analysis showed an increased risk of HAIs among patients with American Society of Anesthesiologists physical status classification system III-IV (odds ratio [OR], 1.39; p<0.001), immunosuppression (OR, 1.80; p=0.013), previous urinary infection (OR, 4.46; p<0,001), and urinary catheter before admission (OR, 1.74; p<0.001). The surgical procedures with the highest incidence of HAIs were radical cystectomy (54.2%) and renal surgery (8.7%). The most frequently isolated microorganisms were Escherichia coli (25.1%), Enterococcus spp. (17.5%), Klebsiella spp. (13.5%) and Pseudomonas aeruginosa (12.3%). Enterococcus sp was the most common microorganism after radical cystectomy and in surgical site infections, E. coli showed resistance rates of 53.5% for fluoroquinolones, 9.3% for amikacin. The percentage of extended-spectrum betalactamase producing E. coli was 24.7%. Klebsiella spp. showed resistance rates of 47.8% for fluoroquinolones, 7.1% for amikacin and 4.3% for carbapenems. Enterococcus spp showed resistance rates of 1.7% for vancomycin and; P. aeruginosa of 33.3% for carbapenems and 26.2% for amikacin.

CONCLUSIONS

Comorbidities, previous urinary infections, and urinary catheter are risk factors for HAIs. The microorganisms most commonly isolated were E. coli, Enterococcus and P. aeruginosa. Prospective monitoring may decrease the incidence of infections.