Silibinin-loaded chitosan-capped silver nanoparticles exhibit potent antimicrobial, antibiofilm, and anti-inflammatory activity against drug-resistant nosocomial pathogens.

Nanoparticles capped with natural products can be a cost-effective alternative to treat drug-resistant nosocomial infections. Therefore, silibinin-loaded chitosan-capped silver nanoparticles (S-C@AgNPs) were synthesized to evaluate their antimicrobial and anti-inflammatory potential. The S-C@AgNPs plasmon peak was found at 430 nm and had a particle size distribution of about 130 nm with an average hydrodynamic diameter of 101.37 nm. The Scanning Electron Microscopy images showed the presence of sphere-shaped homogeneous nanoparticles. The Fourier Transform Infrared Spectroscopy analysis confirmed the loading of silibinin and chitosan on the AgNPs surface. The minimum inhibitory concentration of the S-C@AgNPs was reported between 3.12 µg/ml to 12.5 µg/ml and a minimum bactericidal concentration between 6.25 µg/ml to 25 µg/ml against drug-resistant nosocomial pathogens. Moreover, concentration-dependent significant inhibition of the biofilm formation was reported against P. aeruginosa (70.21%) and K. pneumoniae (71.02%) at 30 µg/ml, and the highest destruction of preformed biofilm was observed at 100 µg/ml against P. aeruginosa (89.74%) and K. pneumoniae (77.65%) as compared to individual bacterial control. Additionally, the fluorescence live/dead assay for bacterial biofilm confirmed that 100 µg/ml effectively inhibits the biofilm formed by these pathogens. S-C@AgNPs also showed anti-inflammatory activity, which is evident by the significant decrease in the proinflammatory cytokines and chemokines level in THP1 cells treated with LPS. This study concluded that S-C@AgNPs have potent antimicrobial, antibiofilm, and anti-inflammatory properties and could be a potential option for treating drug resistant nosocomial infections.

Unsupervised learning and natural language processing highlight research trends in a superbug.

Introduction: Antibiotic-resistant Acinetobacter baumannii is a very important nosocomial pathogen worldwide. Thousands of studies have been conducted about this pathogen. However, there has not been any attempt to use all this information to highlight the research trends concerning this pathogen. Methods: Here we use unsupervised learning and natural language processing (NLP), two areas of Artificial Intelligence, to analyse the most extensive database of articles created (5,500+ articles, from 851 different journals, published over 3 decades). Results: K-means clustering found 113 theme clusters and these were defined with representative terms automatically obtained with topic modelling, summarising different research areas. The biggest clusters, all with over 100 articles, are biased toward multidrug resistance, carbapenem resistance, clinical treatment, and nosocomial infections. However, we also found that some research areas, such as ecology and non-human infections, have received very little attention. This approach allowed us to study research themes over time unveiling those of recent interest, such as the use of Cefiderocol (a recently approved antibiotic) against A. baumannii. Discussion: In a broader context, our results show that unsupervised learning, NLP and topic modelling can be used to describe and analyse the research themes for important infectious diseases. This strategy should be very useful to analyse other ESKAPE pathogens or any other pathogens relevant to Public Health.

Synthesis of Bioactive Nickel Nanoparticles Using Bacterial Strains from an Antarctic Consortium.

Marine microorganisms have been demonstrated to be an important source for bioactive molecules. In this paper we report the synthesis of Ni nanoparticles (NiSNPs) used as reducing and capping agents for five bacterial strains isolated from an Antarctic marine consortium: Marinomonas sp. ef1, Rhodococcus sp. ef1, Pseudomonas sp. ef1, Brevundimonas sp. ef1, and Bacillus sp. ef1. The NiSNPs were characterized by Ultraviolet-visible (UV-vis) spectroscopy, Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopic analysis. The maximum absorbances in the UV-Vis spectra were in the range of 374 nm to 422 nm, corresponding to the Surface plasmon resonance (SPR) of Nickel. DLS revealed NiSNPs with sizes between 40 and 45 nm. All NiSNPs were polycrystalline with a face-centered cubic lattice, as revealed by XRD analyses. The NiSNPs zeta potential values were highly negative. TEM analysis showed that the NiSNPs were either spherical or rod shaped, well segregated, and with a size between 20 and 50 nm. The FTIR spectra revealed peaks of amino acid and protein binding to the NiSNPs. Finally, all the NiSNPs possess significant antimicrobial activity, which may play an important role in the management of infectious diseases affecting human health.

9-Methoxyellipticine: Antibacterial Bioactive Compound Isolated from Ochrosia elliptica Labill. Roots.

Antibacterial resistance bears a major threat to human health worldwide, causing about 1.2 million deaths per year. It is noteworthy that carbazole derivatives have shown a potential antibacterial activity, for example, 9-methoxyellipticine, which was isolated from Ochrosia elliptica Labill. roots (Apocynaceae) in the present study. An in vitro screening of the antibacterial activity of 9-methoxyellipticine was investigated against four multidrug-resistant (MDR) Klebsiella pneumoniae and Shiga toxin-producing Escherichia coli (STEC O157) as Gram-negative bacteria, in addition to Methicillin-resistant Staphylococcus aureus (MRSA) with Bacillus cereus as Gram-positive bacteria. The compound had significant antibacterial activity against the two Gram-negative isolates and lower activity against the Gram-positive ones. The synergistic use of 9-methoxyellipticine and antibiotics was successfully effective in reducing the MDR microorganisms. Lung pneumonia and kidney infection mice models were used to investigate the compound's efficacy in vivo for the first time. Noteworthy reductions in K. pneumoniae and STEC shedding and the colonization were observed, with a reduction in pro-inflammatory factors and immunoglobulin levels. Other related lesions such as inflammatory cell infiltration, alveolar interstitial congestion, and edema were noticed to occur, lessened to different limits. The anti-STEC and anti-K. pneumoniae activities of 9-methoxyellipticine were revealed, providing a new alternative against MDR nosocomial infections.

Survival of Xanthomonas fragariae on Common Materials.

Xanthomonas fragariae causes strawberry angular leaf spot (ALS), an important disease for the strawberry nursery industry in North America. To identify potential inoculum sources, the survival of X. fragariae was examined on the surfaces of 11 common materials found in nurseries: corrugated cardboard, cotton balls, cotton cloth (t-shirt), strawberry leaf, sheet metal, plastic, rubber, Tyvek, wood (balsa), glass (microscope slide), and latex (latex glove). Prefabricated rectangular samples (7.62 by 2.54 cm) of each material were immersed in a bacterial suspension for 15 min, after which the samples were stored at approximately 20°C (room temperature) or -4°C (the cold storage temperature for dormant plants in strawberry nurseries) for 1, 3, 7, 14, 30, 60, 90, 180, 270, and 365 days after inoculation (DAI). After the storage period elapsed, bacteria were recovered from the surfaces of each of the samples with phosphate-buffered saline (PBS)-soaked cotton balls. Survival rate was determined with a viability real-time quantitative PCR procedure and in a plant bioassay that involved rub inoculation of strawberry leaflets with the PBS-soaked cotton balls used to recover bacteria from the samples. Results showed that X. fragariae could survive on all surfaces but that survival rate differed among materials and storage temperature. All materials were capable of harboring viable bacteria up to 7 DAI when stored at -4°C based on the formation of lesions on inoculated leaves in the plant bioassay. The longest survival observed was 270 DAI on cardboard stored at -4°C. At room temperature, cardboard, cotton balls, cotton t-shirt, and strawberry leaf tissue supported small bacterial populations up to 14 DAI. The information from this study can be used to improve sanitation practices for ALS management in strawberry nurseries.

Synthesis of Bioactive Silver Nanoparticles Using New Bacterial Strains from an Antarctic Consortium.

In this study, we report on the synthesis of silver nanoparticles (AgNPs) achieved by using three bacterial strains Rhodococcus, Brevundimonas and Bacillus as reducing and capping agents, newly isolated from a consortium associated with the Antarctic marine ciliate Euplotes focardii. After incubation of these bacteria with a 1 mM solution of AgNO3 at 22 °C, AgNPs were synthesized within 24 h. Unlike Rhodococcus and Bacillus, the reduction of Ag+ from AgNO3 into Ag0 has never been reported for a Brevundimonas strain. The maximum absorbances of these AgNPs in the UV-Vis spectra were in the range of 404 nm and 406 nm. EDAX spectra showed strong signals from the Ag atom and medium signals from C, N and O due to capping protein emissions. TEM analysis showed that the NPs were spherical and rod-shaped, with sizes in the range of 20 to 50 nm, and they were clustered, even though not in contact with one another. Besides aggregation, all the AgNPs showed significant antimicrobial activity. This biosynthesis may play a dual role: detoxification of AgNO3 and pathogen protection against both the bacterium and ciliate. Biosynthetic AgNPs also represent a promising alternative to conventional antibiotics against common nosocomial pathogens.

An 18-Year Dataset on the Clinical Incidence and MICs to Antibiotics of Achromobacter spp. (Labeled Biochemically or by MAL-DI-TOF MS as A. xylosoxidans), Largely in Patient Groups Other than Those with CF.

Achromobacter spp. are intrinsically multidrug-resistant environmental microorganisms which are known to cause opportunistic, nosocomial, and sometimes chronic infections. The existing literature yields scarcely any larger datasets, especially with regard to the incidence in patient groups other than those with cystic fibrosis. The aim of this study was to fill this gap. We present a retrospective analysis of 314 clinical and 130 screening isolates detected in our diagnostic unit between 2004 and 2021, combined with patients' demographic and clinical information (ward type and length of hospitalization), and the results of routine diagnostic antibiotic MIC determination. We found the apparent increase in prevalence in our diagnostic unit, in which cystic fibrosis patients are an underrepresented group, in large part to be attributable to an overall increase in the number of samples and, more importantly, changes in the diagnostic setting, such as the introduction of rigorous screening for Gram-negative multidrug-resistant pathogens. We found these Achromobacter spp. to be most commonly detected in urine, stool, wounds and airway samples, and found the resistance rates to vary strongly between different sample types. Intestinal carriage is frequently not investigated, and its frequency is likely underestimated. Isolates resistant to meropenem can hardly be treated.

Bilateral parapneumonic pleural effusion with pneumothorax in a patient with covid 19 pneumonia: case report.

Recurrent pyogenic effusion combined with bilateral pneumothorax is a rare complication associated with the COVID-19 infection. Current article presents the case report of a 68-year-old male with the severe community-acquired bilateral polysegmental viral COVID-19 pneumonia. Chest radiography on the 15th day after admission to the hospital showed the presence of air and pleural effusion in the right pleural cavity with collapse of the right lung. Thoracentesis and thoracostomy in the sixth intercostal space on the mid-axillary line were performed. About 1400 ml of a yellowish opaque liquid were evacuated from the pleural cavity. Pleural fluid analysis confirmed an exudative lymphocytic-rich effusion with no growth of acid-fast bacteria (AFB). In the pleural fluid such gram-negative bacteria as Acinetobacter baumannii and Pseudomonas aeruginosa were cultured. Chest computed tomography obtained on the third day after thoracentesis showed radiological sings of bilateral hydropneumothorax. Needle thoracocentesis and new pleural drainage in the second intercostal space on the right midclavicular line were established. Five days later after the second drainage of the pleural space was initiated the patient was diagnosed with pleural empyema and transferred to the Surgical Clinic. This case report highlights that in patients with COVID-19 recurrent pyogenic effusion combined with bilateral pneumothorax may occur.

Vishaghn Dhoop, Nano-Scale Particles with Detoxifying Medicinal Fume, Exhibits Robust Anti-Microbial Activities: Implications of Disinfection Potentials of a Traditional Ayurvedic Air Sterilization Technique.

The rapidly increasing global burden of healthcare associated infections (HAI) is resulting in proportionate increase in chemical disinfection in healthcare settings, adding an extra burden of environmental toxicity. Therefore, alternative disinfection techniques with less or no adverse side-effects need to be explored. In this regard, ayurvedic 'dhoopan' technique involving slow combustion of medicinal herbs, minerals and animal products hold great promise. In this study, dhoopan of a traditionally defined ayurvedic medicinal mix, 'Vishaghn Dhoop' (VD) has been assessed for its anti-microbial potentials against both Gram-positive and negative pathogenic bacteria, Mycobacterium and pathogenic fungus, Candida albicans. Fume generated from slow combustion of VD was subjected to physico-chemical characterization and was assessed for anti-microbial effects. VD fume contained particles of 354 ± 84 nm size, laden with anti-microbial metabolites. On agar plates, VD fumigation reduced bacterial growth by 13 - 38%. Liquid culture aeration with VD fume inhibited bacterial growth by 50 - 85%, and fungal growth by 80%. In real life settings (in vivo), un-sanitized rooms fumigated with VD fumes for 30 min reduced the environmental microbial loads by 10 folds. In addition, the safety of VD fumigation was evaluated through in vitro cytotoxicity assay on human lung epithelial (A549) cells. Cells exposed to media-collected VD fumes for 24 h exhibited normal cyto-safety profile. Collectively, these observations provide scientific evidence in support of a traditional technique of disinfection, which can be fine-tuned to have implications in clinical, healthcare and food industry where, disinfection is a prime requirement.

Effective Antimicrobial Solutions for Eradicating Multi-Resistant and ß-Lactamase-Producing Nosocomial Gram-Negative Pathogens.

Antimicrobial resistance (AMR) remains one of the greatest public health-perturbing crises of the 21st century, where species have evolved a myriad of defence strategies to resist conventional therapy. The production of extended-spectrum ß-lactamase (ESBL), AmpC and carbapenemases in Gram-negative bacteria (GNB) is one such mechanism that currently poses a significant threat to the continuity of first-line and last-line ß-lactam agents, where multi-drug-resistant GNB currently warrant a pandemic on their own merit. The World Health Organisation (WHO) has long recognised the need for an improved and coordinated global effort to contain these pathogens, where two factors in particular, international travel and exposure to antimicrobials, play an important role in the emergence and dissemination of antibiotic-resistant genes. Studies described herein assess the resistance patterns of isolated nosocomial pathogens, where levels of resistance were detected using recognised in vitro methods. Additionally, studies conducted extensively investigated alternative biocide (namely peracetic acid, triameen and benzalkonium chloride) and therapeutic options (specifically 1,10-phenanthroline-5,6-dione), where the levels of induced endotoxin from E. coli were also studied for the latter. Antibiotic susceptibility testing revealed there was a significant association between multi-drug resistance and ESBL production, where the WHO critical-priority pathogens, namely E. coli, K. pneumoniae, A. baumannii and P. aeruginosa, exhibited among the greatest levels of multi-drug resistance. Novel compound 1,10-phenanthroline-5,6-dione (phendione) shows promising antimicrobial activity, with MICs determined for all bacterial species, where levels of induced endotoxin varied depending on the concentration used. Tested biocide agents show potential to act as intermediate-level disinfectants in hospital settings, where all tested clinical isolates were susceptible to treatment.

Antimicrobial activities of spirooxindolopyrrolidine tethered dicarbonitrile heterocycles against multidrug resistant nosocomial pathogens.

BACKGROUND: Microbial infections together with rising drug resistance pose a threat to immunocompromised individual. In this perspective, compounds with spirooxindolopyrrolidine play a significant role in research on antimicrobial drug delivery research owing to their various pharmaceutical activities. Spiroheterocyclic compounds are present in number of medications as active motif due to their exceptional structural properties which enable for easy interaction with the protein of the biological target. Inspired by this biological precedent encouraged to synthesize a new class of dispirooxindole fused pyrrolidine heterocycles via a three-component cycloaddition strategy. MATERIALS AND METHODS: The new class of structurally intriguing spirooxindolopyrrolidines were synthesized through three component cycloaddition process and the structure of products were assigned through spectroscopic analysis. The newly synthesized compounds were assessed for their antimicrobial sensitivity test with standard Kirby Bauer method with common drugs. RESULTS: The structurally unexplored hybrid heterocycles fused spirooxindolopyrrolidine exhibited excellent antimicrobial activity against the common nosocomial microbial pathogens. Of four compounds, the compound bearing a chlorine atom on the aryl ring (4a) exhibited significant antimicrobial activity (zone of inhibition: 9.00 ± 1.00-17.00 ± 0.35 mm and MIC: 16.00-256.00 µg/mL) against selected nosocomial infection causing microbial pathogens. Hence, the compound 4a has been considered as an effective drug of interest in therapeutic field for compacting infectious diseases causing pathogens. CONCLUSION: With an aim of developing more effective and economically more affordable antimicrobial leads with a unique mechanism of action, we have designed and synthesized structurally diverse spirooxindolopyrrolidine tethered hybrids that has been assayed against multidrug resistant nosocomial pathogens. The regioisomer having chloro substituted on the phenyl ring showed potent activity when compared to standard drug. Future studies are required to explicate the pharmacological properties of new hybrid heterocycles that have been synthesized in our laboratory for the novel therapeutic development.

Harmonization of whole-genome sequencing for outbreak surveillance of Enterobacteriaceae and Enterococci.

Whole-genome sequencing (WGS) is becoming the de facto standard for bacterial typing and outbreak surveillance of resistant bacterial pathogens. However, interoperability for WGS of bacterial outbreaks is poorly understood. We hypothesized that harmonization of WGS for outbreak surveillance is achievable through the use of identical protocols for both data generation and data analysis. A set of 30 bacterial isolates, comprising of various species belonging to the Enterobacteriaceae family and Enterococcus genera, were selected and sequenced using the same protocol on the Illumina MiSeq platform in each individual centre. All generated sequencing data were analysed by one centre using BioNumerics (6.7.3) for (i) genotyping origin of replications and antimicrobial resistance genes, (ii) core-genome multi-locus sequence typing (cgMLST) for Escherichia coli and Klebsiella pneumoniae and whole-genome multi-locus sequencing typing (wgMLST) for all species. Additionally, a split k-mer analysis was performed to determine the number of SNPs between samples. A precision of 99.0% and an accuracy of 99.2% was achieved for genotyping. Based on cgMLST, a discrepant allele was called only in 2/27 and 3/15 comparisons between two genomes, for E. coli and K. pneumoniae, respectively. Based on wgMLST, the number of discrepant alleles ranged from 0 to 7 (average 1.6). For SNPs, this ranged from 0 to 11 SNPs (average 3.4). Furthermore, we demonstrate that using different de novo assemblers to analyse the same dataset introduces up to 150 SNPs, which surpasses most thresholds for bacterial outbreaks. This shows the importance of harmonization of data-processing surveillance of bacterial outbreaks. In summary, multi-centre WGS for bacterial surveillance is achievable, but only if protocols are harmonized.

MoWa: A Disinfectant for Hospital Surfaces Contaminated With Methicillin-Resistant Staphylococcus aureus (MRSA) and Other Nosocomial Pathogens.

Introduction: Staphylococcus aureus strains, including methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA), are a main cause of nosocomial infection in the world. The majority of nosocomial S. aureus-infection are traced back to a source of contaminated surfaces including surgery tables. We assessed the efficacy of a mixture of levulinic acid (LA) and sodium dodecyl sulfate (SDS), hereafter called MoWa, to eradicate nosocomial pathogens from contaminated surfaces. Methods and Results: A dose response study demonstrated that MoWa killed 24 h planktonic cultures of S. aureus strains starting at a concentration of (LA) 8.2/(SDS) 0.3 mM while 24 h preformed biofilms were eradicated with 32/1.3 mM. A time course study further showed that attached MRSA bacteria were eradicated within 4 h of incubation with 65/2 mM MoWa. Staphylococci were killed as confirmed by bacterial counts, and fluorescence micrographs that were stained with the live/dead bacterial assay. We then simulated contamination of hospital surfaces by inoculating bacteria on a surface prone to contamination. Once dried, contaminated surfaces were sprayed with MoWa or mock-treated, and treated contaminated surfaces were swabbed and bacteria counted. While bacteria in the mock-treated samples grew at a density of ~104 cfu/cm2, those treated for ~1 min with MoWa (1.0/0.04 M) had been eradicated below limit of detection. A similar eradication efficacy was obtained when surfaces were contaminated with other nosocomial pathogens, such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, or Staphylococcus epidermidis. Conclusions: MoWa kills planktonic and biofilms made by MRSA and MSSA strains and showed great efficacy to disinfect MRSA-, and MSSA-contaminated, surfaces and surfaces contaminated with other important nosocomial pathogens.

Repeated exposure of nosocomial pathogens to silver does not select for silver resistance but does impact ciprofloxacin susceptibility.

The rise of antimicrobial resistant bacteria coupled with a void in antibiotic development marks Antimicrobial Resistance as one of the biggest current threats to modern medicine. Antimicrobial metals are being developed and used as alternative anti-infectives, however, the existence of known resistance mechanisms and limited data regarding bacterial responses to long-term metal exposure are barriers to widespread implementation. In this study, a panel of reference and clinical strains of major nosocomial pathogens were subjected to serial dosage cycles of silver and ciprofloxacin. Populations exposed to silver initially showed no change in sensitivity, however, increasingly susceptibility was observed after the 25th cycle. A control experiment with ciprofloxacin revealed a selection for resistance over time, with silver treated bacteria showing faster adaptation. Morphological analysis revealed filamentation in Gram negative species suggesting membrane perturbation, while sequencing of isolated strains identified mutations in numerous genes. These included those encoding for efflux systems, chemosensory systems, stress responses, biofilm formation and respiratory chain processes, although no consistent locus was identified that correlated with silver sensitivity. These results suggest that de novo silver resistance is hard to select in a range of nosocomial pathogens, although silver exposure may detrimentally impact sensitivity to antibiotics in the long term. STATEMENT OF SIGNIFICANCE: The adaptability of microbial life continuously calls for the development of novel antibiotic molecules, however, the cost and risk associated with their discovery have led to a drying up in the pipeline, causing antimicrobial resistance (AMR) to be a major threat to healthcare. From all available strategies, antimicrobial metals and, more specifically, silver showcase large bactericidal spectrum and limited toxic effect which coupled with a large range of processes available for their delivery made these materials as a clear candidate to tackle AMR. Previous reports have shown the ability of this metal to enact a synergistic effect with other antimicrobial therapies, nevertheless, the discovery of Ag resistance mechanisms since the early 70s and limited knowledge on the long term influence of silver on AMR poses a threat to their applicability. The present study provides quantitative data on the influence of silver based therapies on AMR development for a panel of reference and clinical strains of major nosocomial pathogens, revealing that prolonged silver exposure may detrimentally impact sensitivity to antibiotics.

Efficacy of Lactiplantibacillus plantarum 299 and 299v against nosocomial oropharyngeal pathogens in vitro and as an oral prophylactic treatment in a randomized, controlled clinical trial.

BACKGROUND: Disturbance in the oropharyngeal microbiota is common in hospitalized patients and contributes to the development of nosocomial pneumonia. Lactiplantibacillus plantarum 299 and 299v (Lp299 and Lp299v) are probiotic bacteria with beneficial effects on the human microbiome. AIM: To investigate how Lp299 and Lp299v affect the growth of nosocomial oropharyngeal pathogens in vitro and to evaluate the efficacy in vivo when these probiotics are administered prophylactically in hospitalized patients. METHODS: The in vitro effect of Lp299 and Lp299v on nosocomial respiratory tract pathogens was evaluated using two methods, the co-culture and agar overlay. In the clinical study, patients were randomized to orally receive either probiotics or placebo twice daily during their hospital stay. Oropharyngeal swabs were analyzed at inclusion and every fourth day throughout hospitalization. FINDINGS: All tested pathogens were completely inhibited by both Lp299 and Lp299v using the agar-overlay method. In the co-culture experiment, Lp299 and Lp299v significantly (p < 0.05) reduced the growth of all pathogens except for Enterococcus faecalis co-incubated with Lp299. In the clinical study, daily oral treatment with Lp299 and Lp299v did not influence the development of disturbed oropharyngeal microbiota or nosocomial infection. Proton pump inhibitors, antibiotics, and steroid treatment were identified as risk factors for developing disturbed oropharyngeal microbiota. CONCLUSIONS: Lp299 and Lp299v inhibited pathogen growth in vitro but did not affect the oropharyngeal microbiota in vivo. The ClinicalTrials.gov Identifier for this study is NCT02303301.

Systematic Review and Meta-analysis of Carbapenem Resistance of Acinetobacter baumannii in Iran.

BACKGROUND: The prevalence of carbapenem resistance in Acinetobacter baumannii has been increasing worldwide, and therapeutic options are extremely limited. We performed a systematic review to evaluate the phenotypic and genotypic carbapenem resistance in A.baumannii reported in Iran. METHODS: We systematically searched Pub Med, Web of Science Direct, and Google scholar databases to identify studies addressing the carbapenem resistance of A. baumannii. The selected papers were published between 2005 and 2016, but the sample collection period was between 2002 and 2016. To estimate the prevalence, the Der Simonian and Laird randomized models, a 95% confidence interval, was used. For the heterogeneity check, I2 test was used. The Egger test was used to check the propagation bias. RESULTS: Analysis of data indicates that there was an increase in resistance to carbapenems from 4.5% in 2005 to a 100% prevalence rate in 2016 (65.4 (95% CI: 58.8 - 71.6). CONCLUSION: According to the results of this study, the rate of resistance to carbapenem in A.baumannii has been increasing in Iran. The presence of carbapenem-resistant isolates is a major concern, because carbapenem is the main drug used against Multi Drug Resistant (MDR) isolates.

Antibacterial effect of copper sulfate against multi-drug resistant nosocomial pathogens isolated from clinical samples.

BACKGROUND AND OBJECTIVE: With the emergence of antibiotic resistance and the hospital acquired infection, the interest for antimicrobial agents has recently increased again in public health. Copper is recommended as a supplementary method of increasing biological safety in the hospital environment. The objective of this study was to determine the antibacterial activity of copper sulfate salts on strains of bacterial pathogens isolated from different clinical pictures in different health establishment in Algeria. METHODS: A total of 25 different bacterial isolates (16 Enterobacteriaceae, 5 Staphylococci, and 4 Pseudomonas) were tested for susceptibility to copper sulfate using minimum inhibitory concentration (MIC-Cu) and minimum bactericidal concentrations (MBC-Cu) determinations. All isolates were also tested for susceptibility to six antibiotics. RESULTS: Antibiotic susceptibility studies revealed that 100% of isolates were resistant to one or more antibiotics. Fifty two percent of isolates were very susceptible to copper sulfate, with MICs ranging from 100 to 200 µg/ml. MBC-Cu = 1600 µg/ml showed the best bactericidal effect against the great majority of studied bacteria (52%). A good bactericidal activities of copper sulfate were recorded against Proteus vulgaris and Staphylococcus aureus (MBC/MIC=1). The Gram-negative bacteria isolates which were copper resistant also showed a high resistance to chloramphenicol (r=0.78) and Trimethoprime (r=0.61). Furthermore, the strains that were no-susceptible to three different antimicrobial classes (Escherichia coli, Staphylococcus saprophyticus) were not resistant to copper sulfate. CONCLUSION: Copper sulfate salts has significant antibacterial activity against multi-drug resistant nosocomial pathogens.

Sulfonamide-based diffusible signal factor analogs interfere with quorum sensing in Stenotrophomonas maltophilia and Burkholderia cepacia.

Aim:Stenotrophomonas maltophilia (Sm) and Burkholderia cepacia complex (BCC) are Gram-negative bacterial pathogens, which are typically multidrug resistant and excellent biofilm producers. These phenotypes are controlled by quorum sensing (QS) systems from the diffusible signal factor (DSF) family. We aim to interfere with this QS system as an alternative approach in combatting such difficult-to-treat infections. Materials & methods: A library of sulfonamide-based DSF bioisosteres was synthesized and tested against the major phenotypes regulated by QS. Results & conclusion: Several analogs display significant antibiofilm activity while the majority increase the action of the last-resort antibiotic colistin against Sm and BCC. Most compounds inhibit DSF synthesis in the Sm K279a strain. Our results support the strategy of interfering with QS communications to combat multidrug resistance.

Exploring the Hospital Microbiome by High-Resolution 16S rRNA Profiling.

The aim of this work was to analyze and compare the bacterial communities of 663 samples from a Brazilian hospital by using high-throughput sequencing of the 16S rRNA gene. To increase taxonomic profiling and specificity of 16S-based identification, a strict sequence quality filtering process was applied for the accurate identification of clinically relevant bacterial taxa. Our results indicate that the hospital environment is predominantly inhabited by closely related species. A massive dominance of a few taxa in all taxonomic levels down to the genera was observed, where the ten most abundant genera in each facility represented 64.4% of all observed taxa, with a major predominance of Acinetobacter and Pseudomonas. The presence of several nosocomial pathogens was revealed. Co-occurrence analysis indicated that the present hospital microbial network had low connectedness, forming a clustered topology, but not structured among groups of nodes (i.e., modules). Furthermore, we were able to detect ecologically relevant relationships between specific microbial taxa, in particular, potential competition between pathogens and non-pathogens. Overall, these results provide new insight into different aspects of a hospital microbiome and indicate that 16S rRNA sequencing may serve as a robust one-step tool for microbiological identification and characterization of a wide range of clinically relevant bacterial taxa in hospital settings with a high resolution.

Global Proteome Profiling Reveals Drug-Resistant Traits in Elizabethkingia meningoseptica: An Opportunistic Nosocomial Pathogen.

Elizabethkingia meningoseptica is Gram-negative, rod-shaped opportunistic bacterial pathogen increasingly reported in hospital-acquired outbreaks. This bacterium is well known to thrive in the hospital environment. One of the leading causes of meningitis in pediatric and immune-compromised patients, E. meningoseptica has been noted as a "pathogen of interest" in the context of nosocomial diseases associated with device-related infections in particular. This pathogen's multidrug-resistant phenotype and attendant lack of adequate molecular mechanistic data limit the current approaches for its effective management in hospitals and public health settings. This study provides the global proteome of E. meningoseptica. The reference strain E. meningoseptica ATCC 13253 was used for proteomic analysis using high-resolution Fourier transform mass spectrometry. The study provided translational evidence for 2506 proteins of E. meningoseptica. We identified multiple metallo-ß-lactamases, transcriptional regulators, and efflux transporter proteins associated with multidrug resistance. A protein Car D, which is an enzyme of the carbapenem synthesis pathway, was also discovered in E. meningoseptica. Further, the proteomics data were harnessed for refining the genome annotation. We discovered 39 novel protein-coding genes and corrected four existing translations using proteogenomic workflow. Novel translations reported in this study enhance the molecular data on this organism, thus improving current databases. We believe that the in-depth proteomic data presented in this study offer a platform for accelerated research on this pathogen. The identification of multiple proteins, particularly those involved in drug resistance, offers new future opportunities to design novel and specific antibiotics against infections caused by E. meningoseptica.