Multidrug-resistant Bacteria Research Articles

Escherichia coli from healthy farm animals: Antimicrobial resistance, resistance genes andmobile genetic elements.

The use of antibiotics in agriculture and subsequent environmental pollution are associated with the emergence and spread of multidrug-resistant (MDR) bacteria including Escherichia coli. The aim of this study was to detect antimicrobial resistance, resistance genes and mobile genetic elements of 72 E. coli strains isolated from faeces of healthy farm animals. Disk diffusion test showed resistance to ampicillin (59.7%), tetracycline (48.6%), chloramphenicol (16.7%), cefoperazone and ceftriaxone (13.9%), cefepime and aztreonam (12.5%), norfloxacin and ciprofloxacin (8.3%), levofloxacin (6.9%), gentamicin and amikacin (2.8%) among the studied strains. Antibiotic resistance genes (ARGs) were detected by polymerase chain reaction: the prevalence of blaTEM was the highest (59.7% of all strains), followed by tetA (30.6%), blaCTX-M (11.1%), catA1 (9.7%), less than 5% strains contained blaSHV, cmlA, floR, qnrB, qnrS, tetM. 26.4% of E. coli strains had a MDR phenotype. MDR E. coli more often contained class 1 integrons, bacteriophages, conjugative F-like plasmids, than non-MDR strains. ARGs were successfully transferred from faecalE. colistrains into theE. coliNissle 1917 N4i strain by conjugation. Conjugation frequencies varied from (1.0 ± 0.1) * 10-5 to (7.9 ± 2.6) * 10-4 per recipient. Monitoring mobile genetic elements of E. coli for antibiotic resistance is important for farm animal health, as well as for public health and food safety.

A Comprehensive Review on Phage Therapy and Phage-Based Drug Development.

Phage therapy, the use of bacteriophages (phages) to treat bacterial infections, is regaining momentum as a promising weapon against the rising threat of multidrug-resistant (MDR) bacteria. This comprehensive review explores the historical context, the modern resurgence of phage therapy, and phage-facilitated advancements in medical and technological fields. It details the mechanisms of action and applications of phages in treating MDR bacterial infections, particularly those associated with biofilms and intracellular pathogens. The review further highlights innovative uses of phages in vaccine development, cancer therapy, and as gene delivery vectors. Despite its targeted and efficient approach, phage therapy faces challenges related to phage stability, immune response, and regulatory approval. By examining these areas in detail, this review underscores the immense potential and remaining hurdles in integrating phage-based therapies into modern medical practices.

The aryl hydrocarbon receptor and FOS mediate cytotoxicity induced by Acinetobacter baumannii

Acinetobacter baumannii is a pathogenic and multidrug-resistant Gram-negative bacterium that causes severe nosocomial infections. To better understand the mechanism of pathogenesis, we compare the proteomes of uninfected and infected human cells, revealing that transcription factor FOS is the host protein most strongly induced by A. baumannii infection. Pharmacological inhibition of FOS reduces the cytotoxicity of A. baumannii in cell-based models, and similar results are also observed in a mouse infection model. A. baumannii outer membrane vesicles (OMVs) are shown to activate the aryl hydrocarbon receptor (AHR) of host cells by inducing the host enzyme tryptophan-2,3-dioxygenase (TDO), producing the ligand kynurenine, which binds AHR. Following ligand binding, AHR is a direct transcriptional activator of the FOS gene. We propose that A. baumannii infection impacts the host tryptophan metabolism and promotes AHR- and FOS-mediated cytotoxicity of infected cells.

Identification of a Novel β-Defensin Gene in Gilthead Seabream (Sparus aurata)

The excessive use of antibiotics in aquaculture favors the natural selection of multidrug-resistant bacteria, and antimicrobial peptides (AMPs) could be a promising alternative to this problem. The most studied AMPs in teleost fish are piscidins, hepcidins, and β-defensins. In this work, we have found a new gene (defb2) encoding a type 2 β-defensin in the genome of gilthead seabream, a species chosen for its economic interest in aquaculture. Its open reading frame (192 bp) encodes a protein (71 amino acids) that undergoes proteolytic cleavage to obtain the functional mature peptide (42 amino acids). The genetic structure in three exons and two introns and the six characteristic cysteines are conserved as the main signature of this protein family. In the evolutionary analysis, synteny shows a preservation of chromosomal localization and the phylogenetic tree constructed exposes the differences between both types of β-defensin as well as the similarities between seabream and European seabass. In relation to its basal expression, β-defensin 2 is mostly expressed in the intestine, thymus, skin, and gonads of the gilthead seabream (Sparus aurata). In head kidney leucoytes (HKLs), the expression was very low and did not change significantly when stimulated with various immunocompetent agents. However, the expression was significantly down-regulated in the liver, head–kidney, and blood 4 h post-injection with the fish pathogen Vibrio harveyi. When infected with nodavirus, the expression was downregulated in brain at 7 days post-infection. These results denote a possible complementarity between the expression patterns of β-defensins and hepcidins. Further studies are needed to analyze gene duplications and expression patterns of β-defensins and describe their mechanism of action in seabream and other teleost fish.

A Comprehensive Review of Molecular Mechanisms Leading to the Emergence of Multidrug Resistance in Bacteria

A Comprehensive Review of Molecular Mechanisms Leading to the Emergence of Multidrug Resistance in Bacteria

3D printable gelatin/nisin biomaterial inks for antimicrobial tissue engineering applications.

Modern regenerative medicine approaches can rely on the fabrication of personalised medical devices and implants; however, many of these can fail due to infections, requiring antibiotics and revision surgeries. Given the rise in multidrug resistant bacteria, developing implants with antimicrobial activity without the use of traditional antibiotics is crucial for successful implant integration and improving patient outcomes. 3D printed gelatin-based implants have a broad range of applications in regenerative medicine due to their biocompatibility, ease of modification and degradability. In this paper, we report on the development of gelatin biomaterial inks loaded with the antimicrobial peptide, nisin, for extrusion-based 3D printing to produce scaffolds with controlled porosity, high shape fidelity, and structural stability. Rheological properties were comprehensively studied to develop inks that had shear thinning behaviour and viscoelastic properties to ensure optimal printability and extrudability, and enable precise deposition and structural integrity during 3D printing. The 3D printed scaffolds fabricated from the gelatin/nisin inks demonstrated excellent antimicrobial efficacy (complete kill) against Gram positive bacteria methicillin-resistant Staphylococcus aureus (MRSA). Overall, this ink's high printability and antimicrobial efficacy with the model antimicrobial peptide, nisin, offers the potential to develop customisable regenerative medicine implants that can effectively combat infection without contributing to the development of multidrug resistant bacteria.

Low Silver/Copper Exchange in a Copper-Phosphate Enzyme Nanoflower Hybrid Extremely Enhanced Antimicrobial Efficacy against Multidrug Resistant Bacteria.

Infections caused by bacteria that are resistant to many drugs are a major threat to public health in many countries around the world. Here we demonstrate the creation of heterogeneous catalytic nanomaterials with outstanding antimicrobial properties against several superbugs. We have shown that replacing a small amount of copper in a generated copper-phosphate-enzyme nanoflower hybrid with silver drastically increases the antimicrobial capacity of the nanomaterial. In this sense, it has been confirmed that the exchange generated silver phosphate nanoparticles on the Cu nanoflowers, with control of the nanoparticle diameter size. The Fenton catalytic activity of the Ag-containing nanobiohybrids was affected, showing better performance with lower amounts of silver in the final hybrid. This effect was confirmed by their antimicrobial efficacy against Escherichia coli, where the Ag4Cu32@CALB hybrid displayed a log reduction of 3.9, an efficiency more than 5000 times higher than that obtained with copper nanoflowers (Cu36@CALB). The hybrid also showed excellent efficacy against other bacteria such as Klebsiella pneumoniae, Pseudomonas aeruginosa, and Mycobacterium smegmatis with log reductions of 7.6, 4.3, and 1.8, respectively.

Year-round monitoring of antibiotic-resistant bacteria in pristine uppermost stream and estimation of pollution sources

Studies on the conditions and pollution routes of antibiotic-resistant bacteria (ARB) in rivers can help provide countermeasures against the spread of ARB. This study focused on the pristine uppermost stream of a river, where Escherichia coli (E. coli) and enterococci were detected, although the stream flows through a pristine forest catchment. Antibiotic resistance of E. coli and enterococci isolated from the river water, riverbed sediment, and feces of waterside animals, such as birds and Mustelidae, were investigated throughout the year in the pristine uppermost sites. Antibiotic resistance was present in 1.4% (7/494) of the E. coli strains and 3.0% (24/812) of the enterococcal strains, and was low throughout the year. Although antibiotic resistance of bacteria isolated from feces was not detected in this watershed, the prevalence of multidrug-resistant E. coli was 0.4% (1/246) and 0.6% (1/172) in river water and riverbed sediment samples, respectively were observed. The presence of extended-spectrum β-lactamase (ESBL)-producing E. coli was confirmed in river water samples, and genomic analysis revealed that the samples possessed the CTX-M-15 group. Multidrug-resistant strains and ESBL-producing strains were classified as phylogroups B1 and A, respectively, which are E. coli phenotypes isolated from wild animals. Pulsed-field gel electrophoresis revealed analysis targeting enterococci that strains isolated from river water and bird feces were in the same cluster with 100% similarity. Therefore, bird feces are a source of enterococci in the uppermost stream of the river. Because multidrug-resistant bacteria and ESBL-producing bacteria were present in the pristine uppermost stream of the pristine river, urgent elucidation of the spreading routes of ARB is important.

Photocatalysis Inhibits the Emergence of Multidrug-Resistant Bacteria in an Antibiotic-Resistant Bacterial Community in Aquatic Environments.

Bacterial antibiotic resistance has recently attracted increasing amounts of attention. Here, an artificially antibiotic-resistant bacterial community (ARBC) combined with five different constructed antibiotic-resistant bacteria (ARB) with single antibiotic resistance, namely, kanamycin (KAN), tetracycline (TET), cefotaxime (CTX), polymyxin B (PB), or gentamicin (GEM), was studied for the stress response to photocatalysis. With photocatalytic inactivation, the transfer and diffusion of antibiotic resistance genes (ARGs) in the ARBC decreased, and fewer multidrug-resistant bacteria (MDRB) emerged in aquatic environments. After several days of photocatalytic inactivation or Luria broth cultivation, >90% ARB were transformed to antibiotic-susceptible bacteria by discarding ARGs. Bacteria with double antibiotic resistance were the dominant species (99%) of residual ARB. The changes in ARG abundance varied, decreasing for the GEM and TET resistance genes and increasing for the KAN resistance genes. The change in the antibiotic resistance level was consistent with the change in ARG abundance. Correspondingly, point mutations occurred for the KAN, CTX and PB resistance genes after photocatalytic inactivation, which might be the reason why these genes persisted longer in the studied ARBC. In summary, photocatalytic inactivation could reduce the abundance of some ARGs and inhibit the emergence of MDRB as well as block ARG transfer in the bacterial community in aquatic environments. This work highlights the advantages of long-term photocatalytic inactivation for controlling antibiotic resistance and facilitates a better understanding of bacterial communities in real aquatic environments.

Potential of training of anti-Staphylococcus aureus therapeutic phages against Staphylococcus epidermidis multidrug-resistant isolates is restricted by inter- and intra-sequence type specificity.

Phage therapy appears to be a promising approach to tackle multidrug-resistant bacteria, including staphylococci. However, most anti-staphylococcal phages have been characterized in Staphylococcus aureus, while a limited number of studies investigated phage activity against S. epidermidis. We studied the potential of phage training to extend the host range of two types of anti-S. aureus phages against S. epidermidis isolates. The Appelmans protocol was applied to a mixture of Kayvirus and a mixture of Silviavirus phages repeatedly exposed to seven S. epidermidis strains representative of nosocomial-associated sequence types (ST), including the world-wide disseminated ST2. We observed increased activity only for the Kayvirus mixture against two of these strains (ST2 or ST35). Phage subpopulations isolated from the training mixture using these two strains (five/strain) exhibited different evolved phenotypes, active only against their isolation strain or strains of the same ST. Of note, 16/47 ST2 strains were susceptible to one of the groups of trained phages. A comparative genomic analysis of ancestral and trained phage genomes, conducted to identify potential bacterial determinants of such specific activity, found numerous recombination events between two of the three ancestors. However, a small number of trained phage genes had nucleotide sequence modifications impacting the corresponding protein compared to ancestral phages, two to four of them per phage genome being specific of each group of phage subpopulations exhibiting different host range. The results suggest that anti-S. aureus phages can be adapted to S. epidermidis isolates but with inter- and intra-ST specificity.ImportanceS. epidermidis is increasingly recognized as a threat for public health. Its clinical importance is notably related to multidrug resistance. Phage therapy is one of the most promising alternative therapeutic strategies to antibiotics. Nonetheless, only very few phages active against this bacterial species have been described. In the present study, we showed that phage training can be used to extend the host range of polyvalent Kayvirus phages within the Staphylococcus genera to include S. epidermidis species. In the context of rapid development of phage therapy, in vitro forced adaptation of previously characterized phages could be an appealing alternative to fastidious repeated isolation of new phages to improve the therapeutic potential of a phage collection.

Novel composite of nano zinc oxide and nano propolis as antibiotic for antibiotic-resistant bacteria: a promising approach

This study proposes an innovative approach to combat the escalating threat of antibiotic resistance in bacteria by introducing a novel ZnO-propolis nanocomposite (ZnO-P NCs). The overuse of antibiotics, particularly during events like the COVID-19 pandemic, has intensified bacterial resistance, necessitating innovative solutions. The study employs a cost-effective and controllable biosynthesis method to produce ZnO nanoparticles (ZnO-NPs), with propolis extract crucially contributing to the reduction and stabilization of Zn2+ ions. A biodegradable nano-propolis matrix is then created by incorporating ZnO-NPs, forming the ZnO-P NCs. Structural stability is confirmed through FT-IR and Zeta potential analysis, while nanoscale properties are validated via TEM, SEM, and XRD analyses. The antimicrobial efficacy of various substances, including propolis, nano propolis, ethanolic propolis extract, ZnO-NPs, and ZnO-P NCs, is assessed against Gram-negative and Gram-positive bacteria, alongside a comparison with 28 antibiotics. Among the bacteria tested, Pseudomonas aeruginosa PAO1 ATCC15692 was more sensitive (40 mm) to the biosynthesized nanocomposite ZnO-P NCs than to ZnO-NPs (38 mm) and nanopropolis (32 mm), while Escherichia coli was resistant to nanopropolis (0 mm) than to ZnO-NPs (31 mm), and ZnO-P NCs (34 mm). The study reveals a synergy effect when combining propolis with green-synthesized ZnO-NPs in the form of ZnO-P NCs, significantly improving their efficiency against all tested bacteria, including antibiotic-resistant strains like E. coli. The nanocomposite outperforms other materials and antibiotics, demonstrating remarkable antibacterial effectiveness. SEM imaging confirms the disruption of bacterial cell membranes by ZnO-NPs and ZnO-P NCs. The study emphasizes the potential applications of ZnO-NPs integrated into biodegradable materials and underscores the significance of the zinc oxide-propolis nanocomposite in countering antimicrobial resistance. Overall, this research offers a comprehensive solution to combat multidrug-resistant bacteria, opening avenues for novel approaches in infection control.

Green Synthesis of Nanomaterials with Phytochemicals for Treating Multidrug Resistant Bacteria

The Bacteria with Multidrug resistance and Extreme drug resistance are increasing at a rapid rate. Various methods have been employed to combat drug resistant bacteria. Major classes of antibiotics aren’t effective against these bacteria. Alternative methods have been studied in recent years. Nanoparticles are used against multidrug resistant bacteria; The green synthesized nanoparticles are more reliable due to more shelf life and lesser toxicity relative to chemically synthesized nanoparticles. Multi drug resistant E. coli and Staphylococcus aureus was isolated from sewage samples. Green synthesized nanoparticles from various plants samples have been prepared with Zinc and Copper forming respective oxides with Neem, Nakara, Jatropha, Mango, Clove, Ginger, Cardamom, Cinnamon and Betel against multidrug resistant Escherichia coli and Staphylococcus aureus. Isolated E. coli was susceptible to Fluoroquinolone and Augmentin whereas S. aureus was susceptible to vancomycin. Green synthesized nanoparticles had more antimicrobial activity against E. coli and S. aureus than chemically synthesized nanoparticles and plant extracts. Green synthesized Nakara CuO nano particles had inhibition zone of 31 ±0.6mm and 30 ±0.7mm for E. coli and S. aureus respectively, ZnO nano particles of Nakara had 25 ±0.6mm inhibition zone for E. coli and S. aureus. Green synthesized Jatropha CuO nano particles had inhibition zone of 26 ±0.5 and 26 ±0.4mm for E. coli and S. aureus. ZnO nano particles of Jatropha had 31±0.7mm and 30±0.7mm inhibition zone for E. coli and S. aureus respectively. The Scanning electron microscopy studies revealed 26nm Jatropha ZnO and 25nm Nakara CuO nanoparticles. Nano materials were found to be non-toxic in cell line studies. The present study concludes to study the impact of green synthesized nanoparticles as an alternative to antibiotics to combat multidrug resistant bacteria.

Etiology and antimicrobial susceptibility patterns of bacteria causing pneumonia among adult patients with signs and symptoms of lower respiratory tract infections during the COVID-19 pandemic in Mwanza, Tanzania: a cross-sectional study

BackgroundBacterial pneumonia is among the leading causes of morbidity and mortality worldwide. The extensive misuse and overuse of antibiotics observed during the Corona Virus Disease 2019 (COVID-19) pandemic may have changed the patterns of pathogens causing bacterial pneumonia and their antibiotic susceptibility profiles. This study was designed to establish the prevalence of culture-confirmed bacterial pneumonia and describe their antimicrobial susceptibility profile in adult patients who presented with signs and symptoms of lower respiratory tract infections (LRTIs) during the COVID-19 pandemic.MethodologyThis hospital-based cross-sectional study was conducted from July 2021 to July 2022 at a zonal referral hospital and two district hospitals in Mwanza, Tanzania. Demographic and clinical data were collected using a standardized questionnaire. Sputum samples were processed by conventional culture followed by the identification of isolates and antibiotic susceptibility testing. Descriptive data analysis was performed using STATA version 15.0.ResultsA total of 286 patients with a median age of 40 (IQR 29–60) years were enrolled in the study. More than half of the patients enrolled were females (52.4%, n = 150). The overall prevalence of bacterial pneumonia was 34.3% (n = 98). The majority of the bacterial pathogens isolated were Gram-negative bacteria (GNB) (61.2%, 60/98), with a predominance of Klebsiella spp., 38.8% (38/98), followed by Streptococcus pyogenes (21.4%, 21/98). Multi drug resistant (MDR) bacteria were detected in 72/98 (73.5%) of the isolates. The proportions of GNB-resistant strains were 60.0% (36/60) for ciprofloxacin, 60% (36/60) for amoxicillin, 60% (36/60) for amoxicillin, 68.3% (41/60) for trimethoprim-sulfamethoxazole and 58.3% (35/60) for ceftriaxone.ConclusionOne-third of the patients with signs and symptoms of LRTIs had laboratory-confirmed bacterial pneumonia with a predominance of Gram negative MDR bacteria. This calls for continuous antimicrobial resistance (AMR) surveillance and antimicrobial stewardship programs in the study setting and other settings in developing countries as important strategies for tackling AMR.

Genome sequences of 70 multidrug-resistant Gram-negative isolates in high-risk neonates in the Northeast of Mexico.

Infections by multidrug-resistant pathogens are steadily increasing worldwide. A considerable proportion of neonatal intensive care admissions have a bacterial infection with multidrug-resistant bacteria during their hospital stay. In this work, we report draft genome sequences of 70 selected isolates from high-risk neonates in the Northeast of Mexico.

Vibriocidal efficacy of Bifidobacterium bifidum and Lactobacillus acidophilus cell-free supernatants encapsulated in chitosan nanoparticles against multi-drug resistant Vibrio cholerae O1 El Tor

BackgroundCholera is a diarrheal disease recognized for being caused by toxin-producing Vibrio (V.) cholerae. This study aims to assess the vibriocidal and immunomodulatory properties of derived cell-free supernatants (CFSs) of Bifidobacterium (B.) bifidum and Lactobacillus (L.) acidophilus encapsulated in chitosan nanoparticles (CFSb-CsNPs and CFSa-CsNPs) against clinical multi-drug resistance (MDR) isolates of V. cholerae O1 El Tor.MethodsWe synthesized CFSb-CsNPs and CFSa-CsNPs using the ionic gelation technique. The newly nanostructures were characterized for size, surface zeta potential, morphology, encapsulation efficacy (EE), stability in different pH values and temperatures, release profile, and in vitro cytotoxicity. The antimicrobial and antibiofilm effects of the obtained nanocomposites on clinical MDR isolates (N = 5) of V. cholerae E1 Tor O1 were investigated by microbroth dilution assay and crystal violet staining, respectively. We conducted quantitative real-time PCR (qRT-PCR) to analyze the relative gene expressions of Bap, Rbmc, CTXAB, and TCP in response to CFSb-CsNPs and CFSa-CsNPs. Additionally, the immunomodulatory effects of formulated structures on the expression of TLR2 and TLR4 genes in human colorectal adenocarcinoma cells (Caco-2) were studied.ResultsNano-characterization analyses indicated that CFSb-CsNPs and CFSa-CsNPs exhibit spherical shapes under scanning electron microscopy (SEM) imaging, with mean diameters of 98.16 ± 0.763 nm and 83.90 ± 0.854 nm, respectively. Both types of nanoparticles possess positive surface charges. The EE% of CFSb-CsNPs was 77 ± 4.28%, whereas that of CFSa-CsNPs was 62.5 ± 7.33%. Chitosan (Cs) encapsulation leads to increased stability of CFSs in simulated pH conditions of the gastrointestinal tract in which the release rates for CFSb-CsNPs and CFSa-CsNPs were reached at 58.00 ± 1.24% and 55.01 ± 1.73%, respectively at pH = 7.4. The synergistic vibriocidal effects observed from the co-administration of both CFSb-CsNPs and CFSa-CsNPs, as evidenced by a fractional inhibitory concentration (FIC) index of 0.57, resulting in a significantly lower MIC of 2.5 ± 0.05 mg/mL (p < 0.0001) compare to individual administration. The combined antibacterial effect of CFSb-CsNPs and CFSa-CsNPs on Bap (0.14 ± 0.05), Rbmc (0.24 ± 0.01), CTXAB (0.30 ± 0.09), and TCP (0.38 ± 0.01) gene expression was significant (p < 0.001). Furthermore, co-administration of CFSb-CsNPs and CFSa-CsNPs also demonstrated the potency of suppressing TLR 2/4 (0.20 ± 0.01 and 0.12 ± 0.02, respectively) gene expression (p = 0.0019) and reduced Caco-2 cells attached bacteria to 526,000 ± 51,46 colony-forming units/mL (11.19%) (p < 0.0001).ConclusionOur study revealed that encapsulating CFSs within CsNPs enhances their vibriocidal activity by improving stability and enabling a controlled release mechanism at the site of interaction between the host and bacteria. Additionally, the simultaneous use of CFSb-CsNPs and CFSa-CsNPs exhibited superior vibriocidal potency against MDR V. cholerae O1 El Tor strains, indicating these combinations as a potential new approach against MDR bacteria.

Impact of untreated tannery wastewater in the evolution of multidrug-resistant bacteria in Bangladesh

The tannery industry produces one of the worst contaminants, and unsafe disposal in nearby waterbodies and landfills has become an imminent threat to public health, especially when the resulting multidrug-resistant bacteria and heavy metals enter community settings and animal food chains. In this study, we have collected 10 tannery wastewater (TWW) samples and 10 additional non-tannery wastewater (NTW) samples to compare the chemical oxygen demand (COD), pH, biological oxygen demand (BOD), dissolved oxygen (DO), total dissolved solids (TDS), chromium concentration, bacterial load, and antibiotic resistance profiles. While COD, pH, and chromium concentration data were previously published from our lab, this part of the study uncovers that TWW samples had a significantly higher bacterial load, compared to the non-tannery wastewater samples (5.89 × 104 and 9.38 × 103 cfu/mL, respectively), higher BOD and TDS values, and significantly lower DO values. The results showed that 53.4, 46.7, 40.0, and 40.0% of the TWW isolates were resistant to ceftriaxone, erythromycin, nalidixic acid, and azithromycin, respectively. On the other hand, 20.0, 30.0, 50.0, and 40.0% of the NTW isolates were resistant to the same antibiotics, respectively. These findings suggest that the TWW isolates were more resistant to antibiotics than the NTW isolates. Moreover, the TWW isolates exhibited higher multidrug resistance than the NTW isolates, 33.33, and 20.00%, respectively. Furthermore, spearman correlation analysis depicts that there is a negative correlation between BOD and bacterial load up to a certain level (r = − 0.7749, p = 0.0085). In addition, there is also a consistent negative correlation between COD and bacterial load (r = − 0.7112, p = 0.0252) and TDS and bacterial load (r = − 0.7621, p = 0.0104). These findings suggest that TWW could pose a significant risk to public health and the environment and highlight the importance of proper wastewater treatment in tannery industries.

Immunopathology of lung transplantation: from infection to rejection and vice versa.

Lung transplantation offers a lifesaving option for patients with end-stage lung disease, but it is marred by a high risk of post-transplant infections, particularly involving multidrug-resistant bacteria, Cytomegalovirus, and fungal pathogens. This elevated infection rate, the highest among solid organ transplants, poses a significant challenge for clinicians, particularly within the first year post-transplantation, where infections are the leading cause of mortality. The direct exposure of lung allografts to the external environment exacerbates this vulnerability leading to constant immune stimulation and consequently to an elevated risk of triggering alloimmune responses to the lung allograft. The necessity of prolonged immunosuppression to prevent allograft rejection further complicates patient management by increasing susceptibility to infections and neoplasms, and complicating the differentiation between rejection and infection, which require diametrically opposed management strategies. This review explores the intricate balance between preventing allograft rejection and managing the heightened infection risk in lung transplant recipients.

Investigating the interaction of zno nanoparticles with flagellum and fimbriae in multi-drug resistant uropathogenic bacteria encoding fli and fim genes.

Due to the increasing occurrence of drug resistant urinary tract infections (UTI) among children, there is a need to investigate alternative effective treatment protocols such as nanoparticles. Flagella and fimbriae are primary factors contributing the virulence of urinary tract infecting bacteria. The aim of this study was to assess the antibacterial effects of zinc oxide nanoparticles which have been synthesized using both chemical and green methods on multi-drug resistant (MDR) uropathogenic bacteria encoding fli and fim genes and investigating their binding ability to bacterial appendage proteins. A total of 30 urine culture samples were collected from children under 2 years old diagnosed with urinary tract infection. The isolates underwent antibiotic suseptibility assessment and the isolates demonstrating MDR were subjected to molecular amplification of fimG (fimbrial) and fliD and fliT (flagellal) genes. The confirmation of cellular appendages was achieved through silver nitrate staining. The antibacterial efficacy of the synthetized nanoparticles was assessed using the micro and macrodilution methods. The successful binding of nanoparticles to bacterial appendage proteins was confirmed through mobility shift and membrane filter assays. The dimensions of chemically synthesized ZnO nanoparticles and green nanoparticles were measured at 30nm and 85nm, respectively, with the exhibition of hexagonal geometries. The nanoparticles synthesized through chemical and green methods exhibited minimum inhibitory concentrations (MIC) of 0.0062-0.025g/L and 0.3g/L, respectively. The ability of ZnO nanoparticles to bind bacterial appendage proteins and to combat MDR uropathogenic bacteria are promising for new treatment protocols against UTI in children in future.

Overexpression, purification and biochemical studies of Sortase A from Enterococcus faecalis (Ef) and its inhibition studies with Aloenin

Sortase A (SrtA) is a bacterial transpeptidase that garnishes the bacterial surface by adding various virulent factors or proteins by cleaving the LPXTG-specific motif between T and G amino acids. These virulence factors assist in the attachment of host cells, which are essential for bacterial virulence. Enterococcus species are among the multidrug-resistant bacteria that cause nosocomial infections; they have drawn a lot of attention recently. SrtA from E. faecalis (Ef) plays a critical role in pathogenesis, making it a suitable target for the development of antibacterial agents. Since SrtA is not involved in bacterial growth and is present on the surface of bacteria, the probability of developing antibiotic resistance is minimal. In this work, we have done cloning, expression and purification of Ef-SrtA using IMAC (Immobilised Metal Affinity Chromatography) followed by Gel filtration chromatography. Purified Ef-SrtA showed maximum activity at pH-8 and temperature between 45 and 55 °C. The fluorescent assay for kinetic studies of Ef-SrtA showed Vmax 3.852 µM.min−1 and kcat 7.7 × 10−2s−1 for the hydrolysis of substrate using Abz-LPETG-K(Dnp)-NH2. We have selected fifteen Aloe vera extracted compounds and performed virtual screening and docking experiments to identify potential inhibitors against Ef-SrtA. Among fifteen molecules, Aloenin-a which was bound to the active site with a binding energy of -6.1 kcal/mol, interacted with the active site residues, Arg139, Pro105, Leu39, Ala46, and Cys126. Aloenin-a showed a significant inhibitory effect against Ef-SrtA, with an IC50 value of 20.68 µM. Aloenin-a inhibits biofilm formation at concentrations of 20–250 µg/mL. The fibrinogen assay showed adherence to fibrinogen was reduced in the presence of Aloenin-a for E. faecalis. The results demonstrated that Aloe vera extracts containing Aloenin-a can be a significant antagonist of Ef-SrtA.

Importance and prevalence of multidrug-resistant gram-negative bacteria in Germany

Infections with multidrug-resistant gram-negative bacterial species are a great concern in clinics in Germany. By limiting therapeutic options dramatically, these bacteria pose a significant threat to patient health and cause extensive pressure on hygiene systems and patient management. In Germany, the recommendations on how to deal with these bacteria are called MRGN classification, using the terms 3MRGN and 4MRGN for bacteria resistant to three or four major classes of antibiotics. To be resistant to this large number of antibiotics and become classified as 3MRGN or 4MRGN, bacterial strains need to acquire multiple resistance mechanisms with beta-lactamases, especially carbapenemases, being the most important ones. According to established surveillance systems like national reporting systems, KISS or the National Reference Centre, multidrug-resistant bacteria are constantly on the rise in Germany. Although several novel therapeutic options have been approved recently, these bacteria represent a constant challenge and it may be necessary to discuss if the present hygiene recommendations need an update for an efficient and targeted prevention of transmission.