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2.
Pathogens ; 13(6)2024 Jun 07.
Article in English | MEDLINE | ID: mdl-38921783

ABSTRACT

The Arabian Peninsula's endemic ungulate, Oryx leucoryx, was on the verge of extinction at the end of the 1970s. Despite the different reintroduction programs, the International Union for Conservation of Nature is still classifying it as Vulnerable. Among other factors, their vulnerability lies in their susceptibility to specific etiological agents that affect livestock, necessitating health monitoring and strict preventive/biosecurity measures. Within this frame, the current work investigated the determination of the etiological agent potentially involved with cutaneous lesions observed in eight males of Arabian oryx within one of the several national governance conservation programs. Microscopic examination from one animal specimen suggested theileriosis association, which was confirmed by molecular tools using 18S gene sequencing and the report of a novel Theileria sp. not clustering with previously reported antelope sequences. This finding prompts further explorations into the disease dynamics within the Arabian oryx population, especially with the scarcity of data in Qatar about tick-borne pathogens and their transmission.

3.
Sci Rep ; 14(1): 12127, 2024 05 27.
Article in English | MEDLINE | ID: mdl-38802469

ABSTRACT

Antibiotic resistance is a paramount global health issue, with numerous bacterial strains continually fortifying their resistance against diverse antibiotics. This surge in resistance levels primarily stems from the overuse and misuse of antibiotics in human, animal, and environmental contexts. In this study, we advocate for exploring alternative molecules exhibiting antibacterial properties to counteract the escalating antibiotic resistance. We identified a synthetic antimicrobial peptide (AMP) by using computational search in AMP public databases and further engineering through molecular docking and dynamics. Microbiological evaluation, cytotoxicity, genotoycity, and hemolysis experiments were then performed. The designed AMP underwent rigorous testing for antibacterial and antibiofilm activities against Methicillin-Resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli), representing gram-positive and gram-negative bacteria, respectively. Subsequently, the safety profile of the AMP was assessed in vitro using human fibroblast cells and a human blood sample. The selected AMP demonstrated robust antibacterial and antibiofilm efficacy against MRSA and E. coli, with an added assurance of non-cytotoxicity and non-genotoxicity towards human fibroblasts. Also, the AMP did not demonstrate any hemolytic activity. Our findings emphasize the considerable promise of the AMP as a viable alternative antibacterial agent, showcasing its potential to combat antibiotic resistance effectively.


Subject(s)
Anti-Bacterial Agents , Antimicrobial Peptides , Biofilms , Escherichia coli , Methicillin-Resistant Staphylococcus aureus , Microbial Sensitivity Tests , Biofilms/drug effects , Methicillin-Resistant Staphylococcus aureus/drug effects , Escherichia coli/drug effects , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Humans , Antimicrobial Peptides/pharmacology , Antimicrobial Peptides/chemistry , Molecular Docking Simulation , Hemolysis/drug effects , Computer Simulation
4.
Antibiotics (Basel) ; 13(3)2024 Feb 21.
Article in English | MEDLINE | ID: mdl-38534638

ABSTRACT

Antimicrobial resistance (AMR) is a global healthcare challenge with substantial morbidity, mortality, and management costs. During the COVID-19 pandemic, there was a documented increase in antimicrobial consumption, particularly for severe and critical cases, as well as noticeable travel and social restriction measures that might influenced the spectrum of AMR. To evaluate the problem, retrospective data were collected on bacterial infections and antimicrobial susceptibility patterns in Qatar before and after the pandemic from 1 January 2019 to 31 December 2021, covering 53,183 pathogens isolated from reported infection episodes. The findings revealed a significant resistance pattern for extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-EBC), carbapenem-resistant Enterobacteriaceae (CR-EBC), and carbapenem-resistant Pseudomonas aeruginosa (CRPA), ciprofloxacin-resistant Salmonella and methicillin-resistant Staphylococcus aureus (MRSA). For correlation with social restrictions, ESBL-EBC and MRSA were positively correlated with changing patterns of international travel (ρ = 0.71 and 0.67, respectively; p < 0.05), while CRPA was moderately correlated with the number of COVID-19 hospitalized patients (ρ = 0.49; p < 0.05). CREBC and CRPA respiratory infections were associated with hospitalized patients (OR: 3.08 and 2.00, respectively; p < 0.05). The findings emphasize the challenges experienced during the COVID-19 pandemic and links to international travel, which probably will influence the local epidemiology of AMR that needs further surveillance and control strategies.

6.
Microorganisms ; 12(1)2024 Jan 12.
Article in English | MEDLINE | ID: mdl-38257983

ABSTRACT

The emergence of antimicrobial resistance (AMR), particularly methicillin-resistant Staphylococcus aureus (MRSA), poses a significant global health threat as these bacteria increasingly become resistant to the most available therapeutic options. Thus, developing an efficient approach to rapidly screen MRSA directly from clinical specimens has become vital. In this study, we establish a closed-tube loop-mediated isothermal amplification (LAMP) method incorporating hydroxy-naphthol blue (HNB) colorimetric dye assay to directly detect MRSA from clinical samples based on the presence of mecA and spa genes. In total, 125 preidentified S. aureus isolates and 93 clinical samples containing S. aureus were sourced from the microbiology laboratory at Hamad General Hospital (HGH). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were computed based on conventional PCR. The assay demonstrated 100% specificity, 91.23% sensitivity, 0.90 Cohen Kappa (CK), 100% PPV, and 87.8% NPV for the clinical samples, while clinical isolates exhibited 100% specificity, 97% sensitivity, 0.926 CK, 100% PPV, and 88.89% NPV. Compared to cefoxitin disk diffusion, LAMP provided 100% specificity and sensitivity, 1.00 CK, and 100% for PPV and NPV. The study revealed that the closed-tube LAMP incorporating (HNB) dye is a rapid technique with a turnaround time of less than 1 h and high specificity and sensitivity.

7.
Microbiol Spectr ; : e0058423, 2023 Sep 05.
Article in English | MEDLINE | ID: mdl-37668386

ABSTRACT

Carbapenem resistance among Enterobacterales has become a global health concern. Clinical Escherichia coli isolates producing the metallo ß-lactamase NDM have been isolated from two hospitals in Faisalabad, Pakistan. These E. coli strains were characterized by MALDI-TOF, PCR, antimicrobial susceptibility testing, XbaI and S1 nuclease pulsed-field gel electrophoresis (PFGE), conjugation assay, DNA hybridization, whole genome sequencing, bioinformatic analysis, and Galleria mellonella experiments. Thirty-four blaNDM producing E. coli strains were identified among 52 nonduplicate carbapenem-resistant strains. More than 90% of the isolates were found to be multidrug resistant by antimicrobial susceptibility testing. S1 PFGE confirmed the presence of blaNDM gene on plasmids ranging from 40 kbps to 250 kbps, and conjugation assays demonstrated transfer frequencies of blaNDM harboring plasmids ranging from 1.59 × 10-1 to 6.46 × 10-8 per donor. Whole genome sequencing analysis revealed blaNDM-5 as the prominent NDM subtype with the highest prevalence of blaOXA-1, blaCTX-M-15, aadA2, aac(6')-Ib-cr, and tet(A) associated resistant determinants. E. coli sequence types: ST405, ST361, and ST167 were prominent, and plasmid Inc types: FII, FIA, FIB, FIC, X3, R, and Y, were observed among all isolates. The genetic environment of blaNDM region on IncF plasmids included partial ISAba125, the bleomycin ble gene, and a class I integron. The virulence genes terC, traT, gad, fyuA, irp2, capU, and sitA were frequently observed, and G. mellonella experiments showed that virulence correlated with the number of virulence determinants. A strong infection control management in the hospital is necessary to check the emergence of carbapenem resistance in Gram-negative bacteria.IMPORTANCEWe describe a detailed analysis of highly resistant clinical E. coli isolates from two tertiary care centers in Pakistan including carbapenem resistance as well as common co-resistance mechanisms. South Asia has a huge problem with highly resistant E. coli. However, we find that though these isolates are very difficult to treat they are of low virulence. Thus the Western world has an increasing problem with virulent E. coli that are mostly of low antibiotic resistance, whereas, South Asia has an increasing problem with highly resistant E. coli that are of low virulence potential. These observations allow us to start to devise methodologies to limit both virulence and resistance and combat problems in developing nations as well as the Western world.

8.
Int J Environ Health Res ; 33(12): 1218-1232, 2023 Dec.
Article in English | MEDLINE | ID: mdl-35658652

ABSTRACT

Poor indoor air quality in healthcare settings has been tied with the increase in hospital-acquired infections. Thus, this systematic review was conducted to assess the levels and compositions of bacteria in indoor hospital air in the Middle East and North Africa (MENA) region. We examined results provided by different search engines published between 2000 and 2021. Our data showed that most studies were conducted in Iran (80.9%) with a bacterial concentration mean of 172.9 CFU/m3. Comparing sensitive and non-sensitive areas of hospitals, no significant difference was detected in the mean bacterial concentration. The most investigated sensitive hospital areas were operating rooms and intensive care units with mean indoor bacterial concentrations of 180.3 CFU/m3 and 204.6 CFU/m3, respectively. Staphylococcaceae, Enterobacteriaceae, Pseudomonadaceae, and Bacillaceae were commonly identified bacterial families. In conclusion, the mean concentrations of the airborne bacteria were within the acceptable limit compared to WHO standards (300 CFU/m3) for the air in areas occupied by immunosuppressed people.


Subject(s)
Air Pollution, Indoor , Humans , Air Pollution, Indoor/analysis , Air Microbiology , Hospitals , Bacteria , Middle East , Africa, Northern , Environmental Monitoring
9.
Trop Anim Health Prod ; 54(6): 351, 2022 Oct 20.
Article in English | MEDLINE | ID: mdl-36261738

ABSTRACT

Brucellosis is a significant zoonotic disease and one of the most common neglected diseases worldwide. It can infect a wide range of domestic and wild animal species. Infected animals are usually culled, causing substantial economic losses to animal owners and the country's economy in general. The disease is endemic among cattle, sheep, and goats in many countries around the Middle East and prevalent in most Gulf Cooperation Council countries, comprising a significant public health risk in the region. This study investigated the seroprevalence of brucellosis among camels in Qatar. Two hundred and forty-eight samples were collected from dromedary camels from 28 farms across the entire country. Each sample was tested for Brucella antibodies with both Rose Bengal and competitive enzyme-linked immunosorbent assay. Only samples that tested positive by both tests were considered seropositive for brucellosis. The overall prevalence was (20.6%, 95% CI, 15.7-26.1). The association between sex and seropositivity was slightly significant (Χ2 = 4.32, P = 0.04), with higher seroprevalence in females. Camels below breeding age (i.e., < 4 years old) showed decreased seropositivity (3.4%, 95% CI, 0.1-17.8), compared to (22.8%, 95% CI, 17.4-29.0) seropositivity in camels ≥ 4 years of age, with a significant association between age groups and seropositivity (P = 0.02). Our results indicate that the seroprevalence of brucellosis in Qatar's camels is alarming, mandating more efforts to control the disease. The findings of this study will aid in selecting better effective measures to control camel brucellosis in Qatar. Further studies need to be conducted on Brucella infection among camels to determine the predisposing risk factors and the steps that should be followed to control brucellosis.


Subject(s)
Brucellosis , Cattle Diseases , Goat Diseases , Female , Cattle , Sheep , Animals , Camelus , Seroepidemiologic Studies , Rose Bengal , Qatar/epidemiology , Brucellosis/epidemiology , Brucellosis/veterinary , Goats , Cattle Diseases/epidemiology , Goat Diseases/epidemiology
10.
Microorganisms ; 10(10)2022 Oct 18.
Article in English | MEDLINE | ID: mdl-36296331

ABSTRACT

Airborne bacteria pose a potential risk to human health upon inhalation in the indoor environments of health care facilities. Airborne bacteria may originate from various sources, including patients, workers, and daily visitors. Hence, this study investigates the quantity, size, and identification of airborne bacteria indoors and outdoors of four Primary Health Care Centers (PHCC) in Doha, Qatar. Air samples were collected from the lobby, triage room, and outside environment of the centers, including, Qatar University (QU-HC), Al-Rayyan (AR-HC), Umm-Ghuwailina (UG-HC), and Old Airport (OA-HC) between August 2020 and March 2021, throughout both the hot and the cold seasons. Samples were collected using an Anderson six-stage cascade impactor. The mean of the total colony-forming units was calculated per cubic meter of air (CFU/m3). QU-HC had the lowest mean of total bacterial count compared with other centers in the indoor and outdoor areas with 100.4 and 99.6 CFU/m3, respectively. In contrast, AR-HC had the highest level, with 459 CFU/m3 indoors, while OA-HC recorded the highest bacterial concentration of the outdoor areas with a total mean 377 CFU/m3. In addition, 16S rRNA sequencing was performed for genera identification. Staphylococcus, Acinetobacter, Bacillus, and Pseudomonas were the four most frequently identified bacterial genera in this study. The abundance of airborne bacteria in the four health centers was higher in the cold season. About 46% of the total airborne bacterial count for three PHCC centers exceeded 300 CFU/m3, making them uncompliant with the World Health Organization's (WHO) recommendation for indoor settings. Consequently, an IAQ standards should be shaped to establish a baseline for measuring air pollution in Qatar. Additionally, it is crucial to understand seasonal fluctuations better so that hospitals can avoid rising and spreading infection peaks.

11.
Microb Drug Resist ; 28(7): 824-831, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35675669

ABSTRACT

Salmonella is a major cause of foodborne disease outbreaks worldwide, mainly through poultry. Recently, there has been an increase in multidrug-resistant (MDR) Salmonella infections globally. The increased drug resistance results in increased costs and poorer health outcomes due to unavailability or delayed treatment. This study aims to determine the prevalence of Salmonella in retail raw chicken meat and identify their antimicrobial resistance profiles. A total of 270 retail raw chicken carcasses (local and imported) were collected from three hypermarket chains in Qatar between November 2017 and April 2018. Thirty carcasses were contaminated with Salmonella (11.11%). The prevalence of Salmonella in locally produced chicken was higher than in imported chicken (OR = 2.56, 95% CI: 1.18-5.53, p = 0.016). No significant differences were found between the prevalence and storage temperature or hypermarket chain. The highest resistance rates in the isolates were reported to tetracycline (73.7%) followed by nitrofurantoin (53.3%), ampicillin (50%), amoxicillin-clavulanic acid, ceftriaxone (26.7%), and ciprofloxacin (23.3%). Eight isolates were potential extended-spectrum ß-lactamase-producers, all in imported frozen chicken (p < 0.0001). Additionally, 43.3% of the isolates were MDR and associated with frozen chicken (OR = 16.88, 95% CI: 2.55-111.47, p = 0.002). The findings indicate that while the prevalence of Salmonella in retail chicken in Qatar is moderate, a large proportion of them are MDR.


Subject(s)
Chickens , Drug Resistance, Multiple, Bacterial , Animals , Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial , Meat , Microbial Sensitivity Tests , Prevalence , Salmonella
12.
Antibiotics (Basel) ; 11(6)2022 Jun 07.
Article in English | MEDLINE | ID: mdl-35740180

ABSTRACT

Colistin, a last-resort antibiotic, is used to treat infections caused by multi-drug-resistant Gram-negative bacteria. Colistin resistance can emerge by acquiring the mobile colistin gene, mcr-1, usually plasmid borne. Studies on mcr-1 and its transmissibility are limited in the Middle East and North Africa (MENA) region. Here, we investigated the occurrence of mcr-1 in 18 previously collected Escherichia coli isolates collected from chicken samples in Qatar; whole-genome sequencing was performed to determine the location (plasmid-borne and chromosomal) of mcr-1 in the isolates. Additionally, we assessed the transmissibility of plasmid-borne mcr-1 and its cost on fitness in E. coli biofilms. Our results showed that the E. coli isolates belonged to different sequence types, indicating that mcr-1 was occurring in strains with diverse genetic backgrounds. In silico analysis and transformation assays showed that all the isolates carried mcr-1 on plasmids that were mainly IncI2 types. All the mcr-1 plasmids were found to be transmissible by conjugation. In biofilms, a significant reduction in the number of CFU (≈0.055 logs CFU/mL) and colistin resistance (≈2.19 log CFU/mL) was observed; however, the reduction in resistance was significantly larger, indicating that the plasmids incur a high fitness cost. To our knowledge, this is the first study that investigates mcr-1 transmissibility and persistence in Qatar. Our findings highlight that mcr has the potential to spread colistin resistance to potentially disparate strains and niches in Qatar, posing a risk that requires intervention.

13.
Antibiotics (Basel) ; 10(8)2021 Aug 02.
Article in English | MEDLINE | ID: mdl-34438985

ABSTRACT

The prevalence of patients admitted to intensive care units (ICUs) with SARS-CoV-2 infection who were prescribed antibiotics is undetermined and might contribute to the increased global antibiotic resistance. This systematic review evaluates the prevalence of antibiotic prescribing in patients admitted to ICUs with SARS-CoV-2 infection using PRISMA guidelines. We searched and scrutinized results from PubMed and ScienceDirect databases for published literature restricted to the English language up to 11 May 2021. In addition, we included observational studies of humans with laboratory-confirmed SARS-CoV-2 infection, clinical characteristics, and antibiotics prescribed for ICU patients with SARS-CoV-2 infections. A total of 361 studies were identified, but only 38 were included in the final analysis. Antibiotic prescribing data were available from 2715 patients, of which prevalence of 71% was reported in old age patients with a mean age of 62.7 years. From the reported studies, third generation cephalosporin had the highest frequency amongst reviewed studies (36.8%) followed by azithromycin (34.2%). The estimated bacterial infection in 12 reported studies was 30.8% produced by 15 different bacterial species, and S. aureus recorded the highest bacterial infection (75%). The fundamental outcomes were the prevalence of ICU COVID-19 patients prescribed antibiotics stratified by age, type of antibiotics prescribed, and the presence of co-infections and comorbidities. In conclusion, more than half of ICU patients with SARS-CoV-2 infection received antibiotics, and prescribing is significantly higher than the estimated frequency of identified bacterial co-infection.

14.
Antibiotics (Basel) ; 10(8)2021 Aug 12.
Article in English | MEDLINE | ID: mdl-34439022

ABSTRACT

Antibiotic resistance is a growing public health problem globally, incurring health and cost burdens. The occurrence of antibiotic-resistant bacterial infections has increased significantly over the years. Gram-negative bacteria display the broadest resistance range, with bacterial species expressing extended-spectrum ß-lactamases (ESBLs), AmpC, and carbapenemases. All carbapenem-resistant Enterobacteriaceae (CRE) isolates from pediatric urinary tract infections (UTIs) between October 2015 and November 2019 (n = 30). All isolates underwent antimicrobial resistance phenotypic testing using the Phoenix NMIC/ID-5 panel, and carbapenemase production was confirmed using the NG-Test CARBA 5 assay. Whole-genome sequencing was performed on the CREs. The sequence type was identified using the Achtman multi-locus sequence typing scheme, and antimicrobial resistance markers were identified using ResFinder and the CARD database. The most common pathogens causing CRE UTIs were E. coli (63.3%) and K. pneumoniae (30%). The most common carbapenemases produced were OXA-48-like enzymes (46.6%) and NDM enzymes (40%). Additionally, one E. coli harbored IMP-26, and two K. pneumoniae possessed mutations in ompK37 and/or ompK36. Lastly, one E. coli had a mutation in the marA porin and efflux pump regulator. The findings highlight the difference in CRE epidemiology in the pediatric population compared to Qatar's adult population, where NDM carbapenemases are more common.

15.
Pathogens ; 10(6)2021 Jun 17.
Article in English | MEDLINE | ID: mdl-34204203

ABSTRACT

Little is known about the association between respiratory viral infections and their impact on intestinal microbiota. Here, we compared the effect of influenza types, A and B, and influenza shedding in patients' stools on the gut microbiota diversity and composition. Deep sequencing analysis was performed for the V4 region of the 16S rRNA gene. Fecal samples were collected from 38 adults with active respiratory influenza infection and 11 age-matched healthy controls. Influenza infection resulted in variations in intestinal bacterial community composition rather than in overall diversity. Overall, infected patients experienced an increased abundance of Bacteroidetes and a corresponding decrease in Firmicutes. Differential abundance testing illustrated that differences in gut microbiota composition were influenza type-dependent, identifying ten differentially abundant operational taxonomic units (OTUs) between influenza A- and influenza B-infected patients. Notably, virus shedding in fecal samples of some patients had significantly reduced gut bacterial diversity (p = 0.023). Further taxonomic analysis revealed that the abundance of Bacteroides fragilis was significantly higher among shedders compared to non-shedders (p = 0.037). These results provide fundamental evidence of the direct effect of influenza infection on gut microbiota diversity, as reported in patients shedding the virus.

16.
Antibiotics (Basel) ; 10(5)2021 May 11.
Article in English | MEDLINE | ID: mdl-34064966

ABSTRACT

Avian Pathogenic Escherichia coli (APEC) is the contributing agent behind the avian infectious disease colibacillosis, which causes substantial fatalities in poultry industries that has a significant impact on the economy and food safety. Several virulence genes have been shown to be concomitant with the extraintestinal survival of APEC. This study investigates the antibiotic resistance patterns and APEC-associated virulence genes content in Escherichia coli isolated from non-healthy and healthy broiler chickens from a commercial poultry farm in Qatar. A total of 158 E. coli strains were isolated from 47 chickens from five different organs (air sac, cloacal, kidney, liver, and trachea). Based on genetic criteria, 65% were APEC strains containing five or more virulence genes, and 34% were non-pathogenic E. coli (NPEC) strains. The genes ompT, hlyF, iroN, tsh, vat, iss, cvi/cva, and iucD were significantly prevalent in all APEC strains. E. coli isolates showed 96% resistance to at least one of the 18 antibiotics, with high resistance to ampicillin, cephalothin, ciprofloxacin, tetracycline, and fosfomycin. Our findings indicate high antibiotic resistance prevalence in non-healthy and healthy chicken carcasses. Such resistant E. coli can spread to humans. Hence, special programs are required to monitor the use of antibiotics in chicken production in Qatar.

17.
Microb Drug Resist ; 27(12): 1705-1725, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34077290

ABSTRACT

Objectives: Over the last decades, there has been a significant increase in antimicrobial prescribing and consumption associated with the development of patients' adverse events and antimicrobial resistance (AMR) to the point of becoming a global priority. This study aims at evaluating antibiotic prescribing during COVID-19 pandemic from November 2019 to December 2020. Materials and Methods: A systematic review was conducted primarily through the NCBI database, using PRISMA guidelines to identify relevant literature for the period between November 1, 2019 and December 19, 2020, using the keywords: COVID-19 OR SARS-Cov-2 AND antibiotics restricted to the English language excluding nonclinical articles. Five hundred twenty-seven titles were identified; all articles fulfilling the study criteria were included, 133 through the NCBI, and 8 through Google Scholar with a combined total of 141 studies. The patient's spectrum included all ages from neonates to elderly with all associated comorbidities, including immune suppression. Results: Of 28,093 patients included in the combined studies, 58.7% received antibiotics (16,490/28,093), ranging from 1.3% to 100% coverage. Antibiotics coverage was less in children (57%) than in adults with comorbidities (75%). Broad-spectrum antibiotics were prescribed presumptively without pathogen identifications, which might contribute to adverse outcomes. Conclusions: During the COVID-19 pandemic, there has been a significant and wide range of antibiotic prescribing in patients affected by the disease, particularly in adults with underlying comorbidities, despite the paucity of evidence of associated bacterial infections. The current practice might increase patients' immediate and long-term risks of adverse events, susceptibility to secondary infections as well as aggravating AMR.


Subject(s)
Anti-Bacterial Agents/therapeutic use , COVID-19 Drug Treatment , Adolescent , Adult , Aged , Aged, 80 and over , Anti-Bacterial Agents/administration & dosage , Child , Child, Preschool , Comorbidity , Drug Utilization , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Pandemics , SARS-CoV-2 , Young Adult
19.
ACS Omega ; 6(12): 8081-8093, 2021 Mar 30.
Article in English | MEDLINE | ID: mdl-33817467

ABSTRACT

Hydrophobic microporous polystyrene (PS) fibers are fabricated by a solvent-induced phase-separation-assisted electrospinning method. Zinc oxide (ZnO) and silver-doped zinc oxide (Ag-ZnO) nanomaterials with variable morphologies are added to the PS fibers, to investigate the influence of multifunctional nanofiller addition on the porosity and consequent oil-adsorbing properties for different oil types. The doping of silver as well as the uniformity in particle distribution are confirmed by scanning electron microscopy and the energy-dispersive spectral analyses. The porosity of the fibers and their crystallinity effect depend on the hydrophobicity and surface properties of these microporous nanofilled fibers. Ag-ZnO, specifically in 2 wt %, enhanced the pore size and distribution in PS porous fibers, thereby enhancing the oil-adsorbing property and its hydrophobicity. In-depth analysis of the oil adsorption mechanism is done for the fibers, both qualitatively and quantitatively, to demonstrate its correlation with the structural integrity of the fibers. The PS/2Ag-ZnO composite also exhibits the highest antibacterial performance against Staphylococcus aureus, a general indication of antibiological fouling properties of these oil-separating films. The antifouling/antibacterial activity of the nanoparticles and high oil sorption capacity of the highly porous PS composites show great potential for use in water-treatment-related applications.

20.
Front Microbiol ; 11: 1954, 2020.
Article in English | MEDLINE | ID: mdl-32983006

ABSTRACT

This study was performed to investigate the genotypic causes of colistin resistance in 18 colistin-resistant Klebsiella pneumoniae (n = 13), Escherichia coli (n = 3) and Pseudomonas aeruginosa (n = 2) isolates from patients at the Hamad General Hospital, Qatar. MIC testing for colistin was performed using Phoenix (BD Biosciences, Heidelberg, Germany) and then verified with SensiTest Colistin (Liofilchem, Zona Ind. le, Italy). Strains determined to be resistant (MIC > 4-16 µg/mL) were then whole-genome sequenced (MiSeq, Illumina, Inc.). Sequences were processed and analysed using BacPipe v1.2.6, a bacterial whole genome sequencing analysis pipeline. Known chromosomal modifications were determined using CLC Genomics Workbench v.9.5.3 (CLCbio, Denmark). Two K. pneumoniae isolates (KPN-15 and KPN-19) harboured mcr-8.1 on the IncFII(K) plasmids, pqKPN-15 and pqKPN-19, and belonged to ST383 and ST716, respectively. One E. coli isolate harboured mcr-1.1 on the IncI2 plasmid pEC-12. The other 15 isolates harboured known chromosomal mutations linked to colistin resistance in the PhoPQ two-component system. Also, three K. pneumoniae strains (KPN-9, KPN-10 and KPN-15) showed disruptions due to IS elements in mgrB. To our knowledge, this marks the first description of mcr-8.1 in K. pneumoniae of human origin in Qatar. Currently, more research is necessary to trace the source of mcr-8.1 and its variants in humans in this region.

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