Emergence Of Multidrug Resistance Research Articles

Computational and in vitro analyses of the antibacterial effect of the ethanolic extract of Pluchea indica L. leaves.

The most common gram-negative, Escherichia coli, and gram-positive bacteria, Bacillus spp., have evolved different mechanisms that have caused the emergence of multi-drug resistance. As a result, drugs that block the bacterial growth cycle are needed. Here, in silico and in vitro studies were performed to assess compounds in the Pluchea indica leaf extract, a medicinal plant, that can inhibit bacterial proteins. Briefly, P. indica leaves were extracted using ethanol. The crude extract was then subjected to gas chromatography-mass spectrometry for metabolite screening. Molecular docking simulations with rhomboid protease (Rpro) (Protein data bank ID number: 3ZMI from E. coli and filamenting temperature-sensitive mutant Z (FtsZ) protein data bank ID number: 2VAM from Bacillus subtilis were performed. Moreover, the well diffusion method was used to confirm the antibacterial activity of P. indica leaf extract. A total of 10 compounds were identified in the P. indica extract and used for computational analysis. Based on drug-likeness prediction, P. indica compounds may be drug-like molecules. Binding affinity tests indicated that 10,10-Dimethyl-2,6-dimethylenebicyclo(7.2.0)undecan-5.β.-ol and 11,11-Dimethyl-4,8-dimethylenebicyclo(7.2.0)undecan-3-ol had the most negative values. Accordingly, these compounds may be potential ligands that bind to bacterial proteins. The root mean square fluctuation values was <2 Å, indicating stable fluctuation binding for the ligand-protein complex. According to in vitro antibacterial assays, a high concentration (50%) of the P. indica extract markedly inhibited E. coli and B. subtilis, with inhibitory zone diameters of 31.86±1.63 and 21.09±0.09 mm, respectively. Overall, the compounds in the P. indica leaf extract were identified as functional inhibitors of E. coli and B. subtilis proteins via in silico analysis. This may facilitate development of antibacterial agents.

Codelivery of methotrexate and silibinin by niosome nanoparticles for enhanced chemotherapy of CT26 colon cancer cells

Colon cancer (CC) is one of the most prevalent cancers in the world, and chemotherapy is widely applied to combat it. However, chemotherapy drugs have severe side effects and emergence of multi drug resistance (MDR) is common. This bottleneck can be overcome by niosome nanocarriers that minimize drug dose/toxicity meanwhile allow co-loading of incompatible drugs for combination therapy. In this research, silibinin (Sil) as a hydrophobic drug was loaded into the lipophilic part, and methotrexate (MTX) into the hydrophilic part of niosome by the thin film hydration (TFH) method to form Nio@MS NPs for CT26 colon cancer therapy in vitro. Our results indicated synthesis of ideal niosome nanoparticles (NPs) with spherical morphology, size of ∼100 nm, and a zeta potential of −10 mV. The IC50 value for Nio@MS was determined ∼2.6 µg ml−1, which was significantly lower than MTX-Sil (∼6.86 µg ml−1), Sil (18.46 µg ml−1 ), and MTX (9.8 µg ml−1 ). Further, Nio@MS significantly reduced cell adhesion density, promoted apoptosis and increased gene expression level of caspase 3 and BAX while promoted significant downregulation of BCL2. In conclusion, the design and application of niosome to co-administer Sil and MTX can increase the drugs cytotoxicity, reduce their dose and improve anti-cancer potential by combating MDR.

Secondary metabolite profile of Streptomyces spp. changes when grown with the sub-lethal concentration of silver nanoparticles: possible implication in novel compound discovery.

The decline of new antibiotics and the emergence of multidrug resistance in pathogens necessitates a revisit of strategies used for lead compound discovery. This study proposes to induce the production of bioactive compounds with sub-lethal concentrations of silver nanoparticles (Ag-NPs). A total of Forty-two Actinobacteria isolates from four Saudi soil samples were grown with and without sub-lethal concentration of Ag-NPs (50µgml-1). The spent broth grown with Ag-NPs, or without Ag-NPs were screened for antimicrobial activity against four bacteria. Interestingly, out of 42 strains, broths of three strains grown with sub-lethal concentration of Ag-NPs exhibit antimicrobial activity against Staphylococcus aureus and Micrococcus luteus. Among these, two strains S4-4 and S4-21 identified as Streptomyces labedae and Streptomyces tirandamycinicus based on 16S rRNA gene sequence were selected for detailed study. The change in the secondary metabolites profile in the presence of Ag-NPs was evaluated using GC-MS and LC-MS analyses. Butanol extracts of spent broth grown with Ag-NPs exhibit strong antimicrobial activity against M. luteus and S. aureus. While the extracts of the controls with the same concentration of Ag-NPs do not show any activity. GC-analysis revealed a clear change in the secondary metabolite profile when grown with Ag-NPs. Similarly, the LC-MS patterns also differ significantly. Results of this study, strongly suggest that sub-lethal concentrations of Ag-NPs influence the production of secondary metabolites by Streptomyces. Besides, LC-MS results identified possible secondary metabolites, associated with oxidative stress and antimicrobial activities. This strategy can be used to possibly induce cryptic biosynthetic gene clusters for the discovery of new lead compounds.

Antibacterial activity against multidrug-resistant Salmonella, toxicity and biochemical effects of Moringa oleifera leaf extracts in mice

Abstract. Ngemenya MN, Itoe LO, Awah LA, Asongana R, Ndip RA. 2024. Antibacterial activity against multidrug-resistant Salmonella, toxicity and biochemical effects of Moringa oleifera leaf extracts in mice. Asian J Nat Prod Biochem 22: 43-50. The emergence of multidrug resistance has significantly compromised the treatment of Salmonella infections. The anti-Salmonella activity, toxicity, and biochemical effects of Moringa oleifera Lam. leaf crude extracts were studied by disc diffusion and microdilution against Multidrug-Resistant (MDR) strains. Cytotoxicity was investigated on monkey kidney epithelial cells (LLCMK2) and acute toxicity in BALB/c mice. Both hexane (MOHEX) and methanol (MOMET) extracts produced small zones of inhibition of 8mm at 1 mg and 2 mg per disc, indicating weak activity, but the minimum inhibitory concentration showed high (0.0625 mg/mL) to low activity (10 mg/mL) activity. No minimum bactericidal concentration was recorded at the concentrations tested. The 50% cytotoxic concentration (CC50) for methanol and hexane extracts were 2524 µg/mL and 5004 µg/mL, respectively, indicating a low risk of toxicity. No mortality or adverse effects were recorded in the acute toxicity test. Both extracts had no significant effects (p &lt; 0.05) on renal function and one liver enzyme (alanine aminotransferase), but MOMET significantly increased aspartate aminotransferase (p = 0.04), suggesting possible liver toxicity. The study shows that M. oleifera leaves possess bacteriostatic activity against multidrug-resistant Salmonella and are non-toxic; hence, it is a potential alternative treatment against multidrug-resistant Salmonella. Further studies of fractions and pure natural products of the extracts should be pursued.

Characterization of Salmonella phage of the genus Kayfunavirus isolated from sewage infecting clinical strains of Salmonella enterica.

The emergence of multi-drug resistance in Salmonella, causing food-borne infections, is a significant issue. With over 2,600 serovars in in Salmonella sp., it is crucial to identify specific solutions for each serovar. Phage therapy serves as an alternate treatment option. In this study, vB_SalP_792 phage was obtained from sewage, forming plaques in eight out of 13 tested clinical S. enterica isolates. Transmission electron microscopy (TEM) examination revealed a T7-like morphotype. The phage was characterized by its stability, life cycle, antibiofilm, and lytic ability in food sources. The phage remains stable throughout a range of temperatures (-20 to 70°C), pH levels (3-11), and in chloroform and ether. It also exhibited lytic activity within a range of MOIs from 0.0001 to 100. The life cycle revealed that 95% of the phages attached to their host within 3 min, followed by a 5-min latent period, resulting in a 50 PFU/cell burst size. The vB_SalP_792 phage genome has a dsDNA with a length of 37,281 bp and a GC content of 51%. There are 42 coding sequences (CDS), with 24 having putative functions and no resistance or virulence-related genes. The vB_SalP_792 phage significantly reduced the bacterial load in the established biofilms and also in egg whites. Thus, vB_SalP_792 phage can serve as an effective biocontrol agent for preventing Salmonella infections in food, and its potent lytic activity against the clinical isolates of S. enterica, sets out vB_SalP_792 phage as a successful candidate for future in vivo studies and therapeutical application against drug-resistant Salmonella infections.

Antimicrobial combination effects against multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa strains: A cross-sectional study.

Emergence of multidrug resistance in non-fermenting Gram-negative bacilli is a threat to public health. Combination therapy is a strategy for the treatment of antibiotic-resistant infections. In this cross-sectional study, a total of 63 nonduplicate clinical isolates of Acinetobacter baumannii and Pseudomonas aeruginosawere collected from various specimens. Identification of bacterial isolates was performed by phenotypic and molecular tests. Antibiotic susceptibility patterns and detection of β-lactamase genes were determined using the broth microdilution and polymerase chain reaction (PCR) techniques, respectively. Then, the combined effects analysis was determined by the checkerboard method. Based on the status of resistance to carbapenems (imipenem and meropenem), 25 isolates of each genus were selected for further investigation. For A. baumannii, bla OXA-23, bla OXA-58, and bla OXA-48 genes were positive in 21 (84%), 17 (68%), and 11 (44%) of isolates, respectively. In P. aeruginosa isolates, bla VIM was the most common gene (44%) and other genes including bla IMP, bla NDM, and bla OXA-23 were found in nine (36%), six (24%), and three (12%) isolates, respectively. Meropenem (MER)-tigecycline (TIG) had a significant synergistic effect against 20 (80%) A. baumannii (pvalue < 0.001). This combination was also efficient against 5 (20%) P. aeruginosa isolates. Moreover, the other combination, tigecycline-amikacin (TIG-AMK) was effective against 10 (40%) A. baumannii isolates. The combination of colistin (COL) and MER showed a significant synergistic effect against 21 (84%) A. baumannii (pvalue < 0.001) and 17 (68%) P. aeruginosa isolates (pvalue < 0.001). The MER-TIG and COL-MER combinations are promising options against resistant bacteria. Our study could be helpful for the development of a new treatment recommendation.

Strategic implementation of upflow microbubble airlift photocatalytic process to control heavy metal resistant-MDR bacteria and the associated genes in wastewater

The emergence of multidrug resistance (MDR) and heavy metal resistance (HMR) in bacterial pathogens and genes through mobile genetic elements (MGEs) from wastewater effluents needs to be eradicated using green technology. HMR is critical to controlling antimicrobial resistance but has been neglected in most photocatalytic disinfection (PCD) studies. Advanced photocatalysis in antimicrobial studies requires a strategic approach to enhance the disinfection efficiency. This study applied an optimized upflow airlift photocatalytic reactor (UAPR) with microbubble air and blue light to remove the antimicrobial resistance (HMR–MDR bacteria (HMR–MDRB), HMR genes (HMRGs), antibiotic resistant genes (ARGs) and MGEs) and inhibit pathogenicity in a mixed culture of high-strength HMR–MDRB isolated from wastewater. Stable dissolved oxygen (DO) supplementation and blue light significantly affected the HMRGs and MGE reduction, resulting in enhanced disinfection activity (30 %) and reaction time (60 min) required for the complete inactivation of HMR-MDRB mixed culture. The process effectively reduced the blaNDM-1 (3.37 log), pbrT (2.18 log), intl1 (2.16 log), and tn916/1545 (4.07 log), with a PCD rate constant (kg) of 0.0515 min−1, 0.0359 min−1, 0.0292 min−1, and 0.0662 min−1, respectively. Process mechanism studies showed that the stable supplementation of DO was a critical factor in controlling the type of reactive oxygen species (ROS), resulting in type II ROS, 1O2, as the critical free radical contributing to the reduction of ARGs and integron, whereas h+ was the ROS for pbrT and transposon.

Acquired resistance or tolerance? – in search of mechanisms underlying changes in the resistance profile of Candida albicans and Candida parapsilosis as a result of exposure to methotrexate

The increasing prevalence of fungal strains showing acquired resistance and multidrug resistance is an increasing therapeutic problem, especially in patients with a severely weakened immune system and undergoing chemotherapy. What is also extremely disturbing is the similarity of the resistance mechanisms of fungal cells and other eukaryotic cells, including human cells, which may contribute to the development of cross-resistance in fungi in response to substances used in e.g. anticancer treatment. An example of such a drug is methotrexate, which is pumped out of eukaryotic cells by ABC transmembrane transporters - in fungi, used to remove azoles from fungal cells.For this reason, the aim of the study was to analyze the expression levels of genes: ERG11, MDR1 and CDR1, potentially responsible for the occurrence of cross-resistance in Candida albicans and Candida parapsilosis as a result of fungal exposure to methotrexate (MTX).In vitro exposure of C. albicans and C. parapsilosis strains to methotrexate showed a high increase in resistance to fluconazole and a partial increase in resistance to voriconazole. Analysis of the expression of resistance genes showed varied responses of the tested strains depending on the species. In the case of C. albicans, an increase in the expression of the MDR1 gene was observed, and a decrease in ERG11 and CDR1. However, for C. parapsilosis there was an increase in the expression of the CDR1 gene and a decrease in ERG11 and MDR1.We noted the relationship between the level of resistance to voriconazole and the level of ERG11 gene expression in C. albicans. This indicates that this type of relationship is different for each species. Our research confirms that the mechanisms by which fungi acquire resistance and develop cross-resistance are highly complex and most likely involve several pathways simultaneously. The emergence of multidrug resistance may be related to the possibility of developing tolerance to antimycotics by fungi.

Comprehensive analysis of multiple cytokines to stratify uropathogenic Escherichia coli pathogenesis in mouse model of urinary tract infection

PurposeUrinary tract infection (UTI) is one of the most common human bacterial infections primarily caused by uropathogenic E. coli (UPEC). Empiric treatment in UTI cause emergence of multidrug resistance and limit treatment options. Understanding UTI at the molecular level with respect to the causative pathogen as well as subsequent host response pose an absolute necessity towards appropriate clinical management. This study aimed to investigate host cytokine response in mouse UTI model with respect to bacterial colonization and associated virulence gene expression upon infection. MethodMouse UTI model was established with two clinical UPEC isolates E. coli NP105 and E. coli P025. UPEC colonization in bladder and kidney was evaluated by bacterial culture (CFU/ml). Histopathology of the tissues were examined by hematoxylin and eosin staining. PCR and real time PCR were used to detect the incidence and expression of respective bacterial genes. Cytokine concentrations in tissues and sera were evaluated using ELISA. GraphPad prism version 8.0.2 was used for statistical interpretation. ResultHighest bacterial colonization was observed on 7th and 9th day post infection (p.i). in bladder and kidney of mouse infected with E. coli P025 and E. coli NP105 respectively with a distinct difference in relative expression of fimH and papC adhesin genes in vivo. IL-1β level in tissues and sera of E. coli NP105 and E. coli P025 infected mouse was significantly different but the IL-17A, GCSF, TGF-β levels were comparable. ConclusionThese findings show a role of IL1β to stratify pathogenicity of UPEC in mouse UTI model.

Insights into the anti-Candida albicans properties of natural phytochemicals: An in vitro and in vivo investigation.

Invasive candidiasis, attributed to Candida albicans, has long been a formidable threat to human health. Despite the advent of effective therapeutics in recent decades, the mortality rate in affected patient populations remains discouraging. This is exacerbated by the emergence of multidrug resistance, significantly limiting the utility of conventional antifungals. Consequently, researchers are compelled to continuously explore novel solutions. Natural phytochemicals present a potential adjunct to the existing arsenal of agents. Previous studies have substantiated the efficacy of phytochemicals against C. albicans. Emerging evidence also underscores the promising application of phytochemicals in the realm of antifungal treatment. This review systematically delineates the inhibitory activity of phytochemicals, both in monotherapy and combination therapy, against C. albicans in both in vivo and in vitro settings. Moreover, it elucidates the mechanisms underpinning the antifungal properties, encompassing (i) cell wall and plasma membrane damage, (ii) inhibition of efflux pumps, (iii) induction of mitochondrial dysfunction, and (iv) inhibition of virulence factors. Subsequently, the review introduces the substantial potential of nanotechnology and photodynamic technology in enhancing the bioavailability of phytochemicals. Lastly, it discusses current limitations and outlines future research priorities, emphasizing the need for high-quality research to comprehensively establish the clinical efficacy and safety of phytochemicals in treating fungal infections. This review aims to inspire further contemplation and recommendations for the effective integration of natural phytochemicals in the development of new medicines for patients afflicted with C. albicans.

Attenuation of Las/Rhl quorum sensing regulated virulence and biofilm formation in Pseudomonas aeruginosa PAO1 by Artocarpesin

The emergence of multidrug resistance and increased pathogenicity in microorganisms is conferred by the presence of highly synchronized cell density dependent signalling pathway known as quorum sensing (QS). The QS hierarchy is accountable for the secretion of virulence phenotypes, biofilm formation and drug resistance. Hence, targeting the QS phenomenon could be a promising strategy to counteract the bacterial virulence and drug resistance. In the present study, artocarpesin (ACN), a 6-prenylated flavone was investigated for its capability to quench the synthesis of QS regulated virulence factors. From the results, ACN showed significant inhibition of secreted virulence phenotypes such as pyocyanin (80%), rhamnolipid (79%), protease (69%), elastase (84%), alginate (88%) and biofilm formation (88%) in opportunistic pathogen, Pseudomonas aeruginosa PAO1. Further, microscopic observation of biofilm confirmed a significant reduction in biofilm matrix when P. aeruginosa PAO1 was supplemented with ACN at its sub-MIC concentration. Quantitative gene expression studies showed the promising aspects of ACN in down regulation of several QS regulatory genes associated with production of virulence phenotypes. Upon treatment with sub-MIC of ACN, the bacterial colonization in the gut of Caenorhabditis elegans was potentially reduced and the survival rate was greatly improved. The promising QS inhibition activities were further validated through in silico studies, which put an insight into the mechanism of QS inhibition. Thus, ACN could be considered as possible drug candidate targeting chronic microbial infections.

Detection of Multidrug-Resistant Integrons Associated with Acinetobacter baumannii Isolated from Clinical and Environmental Samples

The emergence of multidrug resistance (MDR) among pathogenic bacteria is a root cause of severe infections. It is threatening to observe that MDR is also found in ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens, which has caused a hike in nosocomial infection. The diminishing spectrum of treatment against these pathogens demands an alternative realm of treatment. One such nosocomial pathogen, Acinetobacter baumannii is known to cause pneumonia, blood stream infection, urinary tract infections, especially affecting immunocompromised individuals. Due to indiscriminate use of antibiotics, these pathogens have gained resistance to major classes of antibiotics through mutation and horizontal gene transfer via mobile genetic elements such as plasmids, transposons and integrons. This study mainly aims at identifying integron mediated drug resistance among clinical and environmental strains of A. baumannii. In this study, A. baumannii strains isolated from clinical and environmental samples were screened for antibiotic susceptibility tests. The multidrug resistant isolates were then checked for the presence of 3 classes of integrons viz Intl1 (Class 1), Intl2 (class 2) and, Intl3 (class 3). The integron region of the positive isolates was sequenced, and the drug-resistance gene cassettes were identified. All the clinical and environmental isolates were multidrug resistant. Three clinical isolates of A. baumannii showed positive amplification to Intl1 at 2kb, while none of the environmental isolates carried integrons, though they were multidrug resistant. The sequencing of the integron region of clinical isolates revealed the presence of three antibiotic resistance genes within the integron that encode resistance to chloramphenicol, rifampin, and aminoglycoside. This study prominently highlights the presence of class 1 integrons carrying different antimicrobial resistance determinants among A. baumannii isolated from clinical samples.

Impact of MDRs on COVID-19 Patients Among Developing Countries

Abstract: The COVID-19 virus has killed more than 6.3 million people worldwide. The misuse of antibiotics increased during epidemics, leading to the spread of MDRs. Although antibiotic use is increasing in both developed and developing countries, the utility level and abuse are higher in developing countries. This could have negative consequences for the vaccine, especially considering that many developing countries reported the emergence of many resistant microbes even before the pandemic. Infectious diseases, social and cultural pressures, and telemedicine facilities can all contribute to the overuse of antibiotics. The emergence of multidrug resistance is a major concern, especially in developing countries where health services are already inadequate and diagnostic capacity and facilities for disease prevention and control are inadequate. This might be the major cause of the extensive spread of such diseases. Improper waste management and disposal in hospitals and communities make it easy for clean water to leak from the area, causing many diseases and causing many antibiotics. The potential for microplastics to be turned into anti-bacterial products is also of particular concern for low- and middle-income countries. In the present review, we aim to examine the impact of multidrug resistance in ESKAPE infections coupled with healthcare-associated infections and determine their risk of secondary infection in COVID-19 patients in low- and middle-income countries during the COVID-19 epidemic from a multidisciplinary perspective, identify the challenge for developing countries and seek solutions to solve this problem.

Multidrug resistance of Botrytis cinerea associated with its adaptation to plant secondary metabolites.

Fungicides are an effective way to control gray mold of grapes, but the pathogen Botrytis cinerea can develop resistance, overcoming the effectiveness of a fungicide that is repeatedly applied. More importantly, the emergence of multidrug resistance (MDR) in the field, where multiple fungicides with different modes of action simultaneously lose their efficacies, is a significant concern. MDR is associated with ATP-binding cassette (ABC) transporters of the pathogen, and certain plant secondary metabolites (PSMs) stimulate the upregulation of ABC transporters, we hypothesized that the pathogen's preadaptation to PSMs might contribute to MDR development. To test this in B. cinerea, ten PSMs, namely, resveratrol, reserpine, chalcone, flavanone, eugenol, farnesol, anethene, camptothecin, salicylic acid, and psoralen, were selected based on their association with ABC transporters involved in fungicide resistance. B. cinerea strain B05.10 was continuously transferred for 15 generations on potato dextrose agar amended with a PSM (PDAP), and sensitivities to PSMs and fungicides were examined on the 5th, 10th, and 15th generations. RNA was extracted from B. cinerea from the selected generations. After 15 generations of culture transfers, an up-regulation was observed in the expression of ABC transporter-encoding genes BcatrB, BcatrD, and BcatrK using quantitative polymerase chain reaction (qPCR). This upregulation was found to contribute to MDR of B. cinerea against two or more fungicides, among azoxystrobin, boscalid, fludioxonil, difenoconazole, prochloraz, and pyrimethanil. This finding was confirmed through genetic transformation. The decreased sensitivity of B. cinerea to fungicides was confirmed as a subsequent MDR phenotype after exposure to camptothecin, flavanone, and resveratrol. Besides, transcriptome analysis also revealed the upregulation of transcription factors related to ABC expression following resveratrol exposure. This suggests that PSMs contributed to inducing preadaptation of B. cinerea, leading to subsequent MDR.IMPORTANCEThe emergence of MDR in plant pathogens is a threat to plant disease management and leads to the use of excessive fungicides. Botrytis cinerea is of particular concern because its MDR has widely emerged in the field. Understanding its genesis is the first step for controlling MDR. In this study, the contribution of PSMs to MDR has been examined. Effective management of this pathogen in agroecosystems relies on a better understanding of how it copes with phytochemicals or fungicides.

Study of bacteriological profile and antibiotic susceptibility pattern of pus isolates in tertiary care hospital

Surgical wound causes invasion of pathogens causing surgical site infections which are commonly polymicrobial in nature. This pus forming infection causes delayed wound healing, wound dehiscence and wound breakdown contributing to important healthcare associated infections (HAI) Multidrug resistance has emerged among organisms isolated in pus sample due to failure of appropriate use of antibiotics.: 1. To study the bacteriological profile of pus samples 2. To determine the antibiotic susceptibility pattern of isolated pathogens from pus samples.The study was conducted in department of microbiology, Shimoga institute of medical sciences, Shimoga from January 2018 to June 2018.All pus samples were processed on blood agar, MacConkey agar and incubated at 37°c under aerobic conditions for 24 hours. The organisms were identified as per standard conventional methods. The antimicrobial susceptibility tests were done by Kirby–Bauer’s Disk Diffusion method on Mueller–Hinton Agar and interpreted as per clinical laboratory standard institution guidelines (CLSI). Out of 350 samples 250 were culture positive 100 were culture negative. Among culture positive most common organism isolated was followed by 86(34.45%), 72(28.8%), 55(22%), 20(8%), 9(3.6%), 2(0.8%), 3(1.2%) 3(1.2%), 3(1.2%). Gram positive organisms were most sensitive for linezolid, vancomycin and least sensitive to cefoxitin, erythromycin. Gram Negative Organisms Were Most Sensitive for Imipenam, Piperacillin tazobactam and least Sensitive for Ampicillin-sulbactam, Ciprofloxacin is most common etiology of pus forming infection most importantly surgical site infections (SSI). MRSA prevalence in hospital set up indicates the failure of proper infection control practices implementation in the hospitals causing healthcare associated infections (HAI). Emergence of multidrug resistance among the pus isolates is because of non-judicious use of antibiotics.

Detection of CTX-M-15 ESBL in XDR Haemophilus parainfluenzae from a urethral swab.

Haemophilus parainfluenzae is an opportunistic pathogen causing respiratory tract infection and sexually transmitted diseases. The emergence of multidrug resistance in this species is particularly worrisome, especially since the recent description of CTX-M-15 ESBL-producing isolates in Spain. The aim of this study was to characterize a CTX-M-15-producing H. parainfluenzae clinical isolate, HP01, obtained from a urethral swab. MICs were determined with gradient strips for this isolate. Hydrolysis assays were performed with the β LACTA test. Genomic DNA from HP01 was subjected to Illumina and Oxford Nanopore sequencing to investigate the genetic environment of blaCTX-M-15. Phylogenetic analysis was performed with available H. parainfluenzae genomes from the NCBI database, including CTX-M-15 producers. HP01, an XDR isolate, was resistant to penicillin, third-generation cephalosporins, fluoroquinolones, macrolides, cyclines and co-trimoxazole and susceptible only to carbapenems and rifampicin. HP01 carried blaTEM-1, blaCTX-M-15, tet(M), catS and mef(E)/mel and harboured amino acid substitutions in PBP3, PBP5, GyrA, ParC and FolA implicated in resistance. Genomic analysis revealed that blaCTX-M-15 was carried by a Tn3-like transposon inserted into a novel integrative and conjugative element (ICE), ICEHpaSLS, present on the chromosome and belonging to the ICEHin1056 family described in Haemophilus influenzae. The tet(M)-MEGA element was also detected on the chromosome. No plasmid was found. The phylogenetic analysis showed that four H. parainfluenzae producing CTX-M-15 clustered in the same clade. Here we report the description of an XDR H. parainfluenzae producing blaCTX-M-15 isolated from a urethral swab. The blaCTX-M-15 gene was inserted into an ICE structure similar to those recently described in CTX-M-15 producers in Spain. The emergence of XDR H. parainfluenzae producing blaCTX-M-15 is a matter of great concern. Careful surveillance is required to prevent its spread.

Epidemiology of bloodstream infections and the impact of antimicrobial resistance in pediatric hematopoietic cell transplant.

Bloodstream infections (BSI) pose a substantial threat to the well-being and survival of patients undergoing hematopoietic stem cell transplantation (HSCT). Risk factors for these infections vary across the different post-HSCT phases. In the pre-engraftment period, patients are particularly susceptible to infection due to prolonged neutropenia, mucosal damage, and extensive use of central venous line (CVL). In the post-engraftment phase, the emergence of graft versus host diseases further compounds the risk. The epidemiology of these infections has undergone notable changes over the years due to multifactorial reasons, including the evolution of protocols that intensify immunosuppression. In this context, the emergence of multi-drug resistance (MDR) microorganisms can be a challenge due to the elevated risk of mortality in these vulnerable patients. Unfortunately, there is a lack of comprehensive data on this topic, particularly in pediatrics. This article aims to provide a summary of the epidemiology of BSI in the different post-transplant phases and the impact of MDR pathogens. Having knowledge about the local epidemiology of BSI can be instrumental in tailoring targeted therapies, leading to improved survival rates in HSCT recipients.

Emergence and genomic characteristics of multi-drug-resistant Salmonella in pet turtles and children with diarrhoea.

Pet turtles are a well-recognized source of human salmonellosis, posing a threat to human health, particularly children who commonly keep pet turtles. To date, the genomic characteristics of Salmonella among pet turtles and children has not been well described. We investigated the prevalence, antimicrobial resistance (AMR) and genomic characteristics of Salmonella from pet turtles in Beijing, China. In total, 9.6 % (46/480) of pet turtles were positive for Salmonella with S. Thompson being the dominant serovar (19/46) in 2019. Moreover, 80.4 % of Salmonella were multi-drug resistant (MDR) and 60.7 % were resistant to ampicillin, streptomycin, sulfonamides and tetracycline (ASSuT). We further compared the genomes of S. Thompson isolates from pet turtles (n=19) with those from children with diarrhoea (n=28) in the same region and year, most of which were sequence type (ST)26, with one novel ST7937 identified from a child-associated isolate. S. Thompson isolates from children with diarrhoea exhibited less resistance than isolates from pet turtles. Most MDR isolates possessed multiple AMR genes, including the AmpC β-lactamase-encoding genes bla DHA-15 and bla DHA-1 which co-occurred with the IncA/C and IncHI plasmid replicon types. To the best of our knowledge, this is the first time that the bla DHA-15 gene has been detected from Salmonella. Several pet turtle-associated S. Thompson isolates comprised phylogenetically close clusters with those from children with diarrhoea (<20 SNP differences). Bayesian analysis demonstrated that the Chinese ST26 S. Thompson strains had a recent evolutionary history and evolved into two major clades, with one clade acquiring various resistant plasmids. Our findings revealed the emergence of MDR Salmonella among pet turtles in China and provided evidence for the interspecies transmission of S. Thompson.

Novel betulin derivatives as multidrug reversal agents targeting P-glycoprotein

Chemotherapy is a powerful means of cancer treatment but its efficacy is compromised by the emergence of multidrug resistance (MDR), mainly linked to the efflux transporter ABCB1/P-glycoprotein (P-gp). Based on the chemical structure of betulin, identified in our previous work as an effective modulator of the P-gp function, a series of analogs were designed, synthesized and evaluated as a source of novel inhibitors. Compounds 6g and 6i inhibited rhodamine 123 efflux in the P-gp overexpressed leukemia cells, K562/Dox, at concentrations of 0.19 µM and 0.39 µM, respectively, and increased the intracellular accumulation of doxorubicin at the submicromolar concentration of 0.098 µM. Compounds 6g and 6i were able to restore the sensitivity of K562/Dox to Dox at 0.024 µM and 0.19 µM, respectively. Structure–activity relationship analysis and molecular modeling revealed important information about the structural features conferring activity. All the active compounds fitted in a specific region involving mainly transmembrane helices (TMH) 4–6 from one homologous half and TMH 7 and 12 from the other, also showing close contacts with TMH 6 and 12. Compounds that bound preferentially to another region were inactive, regardless of their free energy of binding. It should be noted that compounds 6g and 6i were devoid of toxic effects against peripheral blood mononuclear normal cells and erythrocytes. The data obtained indicates that both compounds might be proposed as scaffolds for obtaining promising P-gp inhibitors for overcoming MDR.

Emergence and Distribution of Diverse Serovars of Non-Typhoidal Salmonellae in Mangalore, Coastal Karnataka: A 12-year Experience

Background and Aim: Non-Typhoidal Salmonellae (NTS) is emerging as a major health problem globally. They cause foodborne infections, especially gastroenteritis as well as extraintestinal manifestations. As this is a zoonotic disease, certain animal sources such as poultry, egg, meat and dairy products are implicated. Fruits and vegetables too contaminated by manure of infected animal excreta are possible vehicles of transmission of this disease. The present report analyzes the spectrum of NTS with seroprofiling, isolated in our institute for the last 12 years. Materials and Methods: Fresh fecal samples from patients with acute gastroenteritis and blood samples from cases of bacteremia were processed according to the standard protocol. Nonlactose fermenting colonies resembling Salmonella were subjected to biochemical characterization and antimicrobial susceptibility testing followed by serotyping. Results: One hundred fifty-two NTS strains were isolated from feces and 13 from blood. Serotyping of these strains revealed that the most common NTS species was Salmonella Typhimurium (44.8%), followed by Salmonella Oslo (15.2%) and Salmonella Weltevreden (11.5%). Many rare strains were also encountered in our study. Conclusion: As many of the NTS species are biochemically similar, serotyping of NTS should be made mandatory to know the burden of the disease and to detect the emergence of new serovars. Emergence of multidrug resistance in NTS strains is a major concern nowadays. It is very essential to adopt strict quality measures in poultry, fish, dairy, and meat processing units as they are widely distributed in animals. In addition, strategies should be formulated by health education and public awareness programs to sensitize the population regarding this menace.