Greater Antibiotic Resistance Research Articles

Chitosan‐Stabilized PtAu Nanoparticles with Multienzyme‐Like Activity for Mixed Bacteria Infection Wound Healing and Insights into Its Antibacterial Mechanism

Traditional antibacterial agents are often observed to be ineffective because bacteria evolved to strains with greater antibiotic resistance. Here, vigorous chitosan‐stabilized PtAu nanoparticles (CSPA) with multienzyme‐like activity are successfully fabricated, which serve an effective artificial nanozyme to enhance antibacterial activity for mixed bacterial infection wound treatment. Ultrasmall size CSPA exhibits excellent hydrophilicity and biocompatibility, possesses strong oxidase‐ and peroxidase‐like activity generating a substantial amount of ROS (, 1O2, ·OH) to cause oxidative damage to bacteria, also demonstrates nicotinamide adenine dinucleotide dehydrogenase‐like activity disrupting the bacterial respiratory chains, and subsequently impedes adenosine triphosphate production. CSPA exhibits favorable broad‐spectrum antibacterial activity at very low concentrations, prevents bacterial resistance, and completely inhibits bacterial biofilm formation. Antibacterial Mechanism of CSPA by the transcriptomics is further revealed that CSPA can induce bacterial oxidative stress, hinder bacterial energy metabolism, and disrupt the synthesis and function of bacterial cell walls and cell membranes. In vivo, CSPA inhibits the mixed bacterial population at the wound site and promotes wound healing in rats. This study introduces a novel antibacterial approach, providing important insight into the antibacterial mechanism of CSPA nanozymes and promoting the advancement of nanocatalytic materials in biomedical applications.

Uropathogenic distribution and antibiotic resistance patterns according to multidrug-resistant bacteria colonization status in patients with stroke.

Urinary tract infections (UTI) are common in patients with stroke. The colonization of multidrug-resistant organisms (MDR) has recently become a global issue, and infection with MDR is associated with a poorer prognosis. This study aimed to investigate the uropathogenic distribution in stroke patients according to MDR colonization and investigate the infection risk and antibiotic resistance of each uropathogen to help determine initial antibiotic treatment. This study is a retrospective study conducted on patients who underwent inpatient treatment for stroke at Kosin University Gospel Hospital in 2019 to 2021. The participants were classified into Group VRE if vancomycin-resistant Enterococcus (VRE) colonization was confirmed, Group CRE if carbapenem-resistant Enterobacteriaceae (CRE) colonization was confirmed, and Group Negative if no MDR colonization was confirmed. Urine culture was performed if symptomatic UTI was suspected. Uropathogenic distribution, antibiotic resistance patterns were assessed by one-way analysis of variance, independent t-test, and Pearson chi-square test. And the infection risk factors for each uropathogen were assessed by multinomial logistic regression analysis. Six hundred thirty-three participants were enrolled. The mean age of all participants was 69.77 ± 14.91, with 305 males and 328 females, including 344 hemorrhagic strokes and 289 ischemic strokes. No growth in urine culture was the most common finding (n = 281), followed by Escherichia coli (E.coli) (n = 141), and Enterococcus spp. (n = 80). Group Negative had significantly more cases of no growth in urine culture than Group VRE (Odds ratio [OR], 11.698; 95% confidence interval [CI], 3.566-38.375; P < .001) and than Group CRE (OR, 11.381; 95% CI, 2.665-48.611; P < .001). Group VRE had significantly more E.coli (OR, 2.905; 95% CI, 1.505-5.618; P = .001), and more Enterococcus (OR, 4.550; 95% CI, 2.253-9.187; P < .001) than Group Negative. There was no statistical difference in antibiotic resistance according to MDR colonization in E coli, but for Enterococcus spp., Group VRE and CRE showed significantly more resistance to numerous antibiotics than Group Negative. MDR colonization increases the risk of UTI and is associated with greater antibiotic resistance. For appropriate administration of antibiotics in UTI, continuous monitoring of the latest trends in uropathogenic distribution is required, and clinicians should pay more attention to the use of initial empirical antibiotics in patients with MDR colonization.

Phenotypic and Genotypic Characteristics of Non-Hemolytic L. monocytogenes Isolated from Food and Processing Environments.

Increasingly, Listeria monocytogenes (LM) with atypical phenotypic and genotypic characteristics are being isolated from food, causing problems with their classification and testing. From 2495 soil, food, and swab samples from the food industry, 262 LM isolates were found. A total of 30 isolates were isolated, mainly from soil and plant food, and were classified as atypical LM (aLM) because they lacked the ability to move (30/11.4%) and perform hemolysis (25/9.5%). The isolation environment affected aLM incidence, cell size, sugar fermentation capacity, antibiotic sensitivity, and the number of virulence genes. Therefore, despite several characteristics differentiating all aLMs/non-hemolytic isolates from reference LMs, the remaining phenotypic characteristics were specific to each aLM isolate (like a fingerprint). The aLM/non-hemolytic isolates, particularly those from the soil and meat industries, showed more variability in their sugar fermentation capacity and were less sensitive to antibiotics than LMs. As many as 11 (36.7%) aLM isolates had resistance to four different antibiotics or simultaneously to two antibiotics. The aLM isolates possessed 3-7 of the 12 virulence genes: prfA and hly in all aLMs, while iap was not present. Only five (16.7%) isolates were classified into serogroups 1/2c-3c or 4a-4c. The aLM/non-hemolytic isolates differed by many traits from L. immobilis and atypical L. innocua. The reference method of reviving and isolating LM required optimization of aLM. Statistical analyses of clustering, correlation, and PCA showed similarities and differences between LM and aLM/non-hemolytic isolates due to individual phenotypic traits and genes. Correlations were found between biochemical traits, antibiotic resistance, and virulence genes. The increase in the incidence of atypical non-hemolytic LM may pose a risk to humans, as they may not be detected by ISO methods and have greater antibiotic resistance than LM. aLM from LM can be distinguished based on lack of hemolysis, motility, growth at 4 °C, ability to ferment D-arabitol, and lack of six specific genes.

Characterization of Mixed-Species Biofilms Formed by Four Gut Microbiota.

In natural settings, approximately 40-80% of bacteria exist as biofilms, most of which are mixed-species biofilms. Previous studies have typically focused on single- or dual-species biofilms. To expand the field of study on gut biofilms, we found a group of gut microbiota that can form biofilms well in vitro: Bifidobacterium longum subsp. infantis, Enterococcus faecalis, Bacteroides ovatus, and Lactobacillus gasseri. The increase in biomass and bio-volume of the mixed-species biofilm was confirmed via crystal violet staining, field emission scanning electron microscopy, and confocal laser scanning microscopy, revealing a strong synergistic relationship in these communities, with B. longum being the key biofilm-contributing species. This interaction may be related to changes in the cell number, biofilm-related genes, and metabolic activities. After quantifying the cell number using quantitative polymerase chain reaction, B. longum and L. gasseri were found to be the dominant flora in the mixed-species biofilm. In addition, this study analyzed biological properties of mixed-species biofilms, such as antibiotic resistance, cell metabolic activity, and concentration of water-insoluble polysaccharides. Compared with single-species biofilms, mixed-species biofilms had higher metabolic activity, more extracellular matrix, and greater antibiotic resistance. From these results, we can see that the formation of biofilms is a self-protection mechanism of gut microbiota, and the formation of mixed-species biofilms can greatly improve the survival rate of different strains. Finally, this study is a preliminary exploration of the biological characteristics of gut biofilms, and the molecular mechanisms underlying the formation of biofilms warrant further research.

ANTIBIOTIC RESISTANCE PROFILE OF ISOLATED BACTERIA AT THE SANGMELIMA REFERENCE HOSPITAL, SOUTH CAMEROON REGION: A RETROSPECTIVE STUDY

Background and objective: Bacterial resistance to antibiotics is now one of the most serious threats to global health. Knowledge of the main bacterial species responsible for bacteremia and their antibiotic resistance profile makes possible to provide an objective basis for effective antibiotic therapy. However, in the South Cameroon region, microbiological documentation is not always available. The objective of our study was to determine the resistance profile of bacteria isolated at the Sangmélima Reference Hospital.&#x0D; Methods: It was a retroprospective study on biological samples collected from interned and ambulatory patients seen at the Sangmélima Reference Hospital during the period from January 2021 to October 2021.The samples were cultured on specific media and the susceptibility was carried out on agar media using Kirby-Bauertechnique and interpretation according to the 2020 CASFM Guidelines.&#x0D; Results: For the retrospective part, GNB were most represented (15/26; 57.7%,) with the E. coli (n=12/15) and only Staphylococcus spp for GPB (n=11/26). Staphylococcus resistance was particularly relevant with 81.81% to erythromycin, 63.63% to cefoxitin and 72.72% to Cotrimoxazole. E. coli showed a resistance of 66.66% for augmentin and 83.33% for cefuroxime. In the prospective part, GPB were only represented by Staphylococcus epidermidis (7/7 ; 50%), and GNB included E. coli (3/7 ; 21.42%), K. pneumoniae (2/7; 14.29%) and A baumannii (2/7; 14.29%). For all isolated bacteria strains, a high resistance to the majority of betalactams and penicillin was observed. However, bacteria with greater antibiotic resistance were Staphylococcus strains, highly resistant to beta-lactams, while A. baumannii strains showed higher resistance, and E. coli especially to penicillins and fluoroquinolones.&#x0D; Conclusion: E. coli and Staphylococcus spp were predominant isolated bacteria with high rate of resistance to antibiotics frequently used in hospital. Strict adherence to infection prevention practices and judicious use of antibiotics are recommended to slow te spread of antimicrobial resistance (AMR).&#x0D; &#x0D; Peer Review History: &#x0D; Received: 10 May 2022; Revised: 12 June; Accepted: 30 June, Available online: 15 July 2022&#x0D; Academic Editor: Dr. Emmanuel O. Olorunsola, Department of Pharmaceutics &amp; Pharmaceutical Technology, University of Uyo, Nigeria, olorunsolaeo@yahoo.com&#x0D; UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. &#x0D; Received file: Reviewer's Comments:&#x0D; Average Peer review marks at initial stage: 5.5/10&#x0D; Average Peer review marks at publication stage: 7.0/10&#x0D; Reviewers:&#x0D; Prof. Dr. Hassan A.H. Al-Shamahy, Sana'a University, Yemen, shmahe@yemen.net.ye&#x0D; Dr. Wadhah Hassan Ali Edrees, Hajja University, Yemen, edress2020@gmail.com&#x0D; Similar Articles: &#x0D; THE PRACTICE AND PERCEPTION OF HOSPITAL PHARMACISTS TOWARDS ERRORS IN DISPENSING MEDICINES AND THEIR POSSIBLE CAUSES IN OMDURMAN MILITARY HOSPITAL, SUDAN &#x0D; PATTERN OF ANTIMICROBIAL PRESCRIBING AMONG IN-PATIENTS OF A TEACHING HOSPITAL IN YEMEN: A PROSPECTIVE STUDY

Novel NAD-independent Avibacterium paragallinarum: Isolation, characterization and molecular identification in Iran.

BackgroundInfectious coryza (IC) is an invasive upper respiratory disease caused by Avibacterium paragallinarum that affects birds, particularly chickens. The objective of this study is to isolate, characterize and molecularly identify the bacterium A. paragallinarum in poultry birds, as well as to determine its antibiotic sensitivity and resistance.MethodsA total of 10 chickens from four different Iranian farms with typical IC symptoms were used in this study. The nasal swabs were streaked onto chocolate agar plates and blood agar plates and incubated at 37°C in 5% CO2 for 24 to 48 h. As part of the identification of bacteria, bacteriological observations and polymerase chain reaction (PCR) testing are conducted. The antibiotic sensitivity tests were also performed using the disk diffusion method against A. paragallinarum and the prevalence in different farms was determined.ResultsBy using biochemical assays and PCR analyses, seven strains of A. paragallinarum were isolated from samples of four chicken farms with typical IC clinical signs. Most isolates (4/7) showed the typical requirement for nicotinamide adenine dinucleotide (NAD) and an enriched CO2 atmosphere for growth. Three of the seven strains of A. paragallinarum were found to be novel NAD‐independent under anaerobic conditions. There was one biochemical biovar identified in terms of carbohydrate fermentation patterns, although changes in maltose carbohydrate fermentation patterns were detected in the No. 5 strain. All isolates were sensitive to gentamicin and spectinomycin. Three novel NAD‐independent strains (Nos.1, 5 and 7) were found to be multidrug‐resistant (MDR) and resistant to at least three classes of antibiotics. There was greater antibiotic resistance in the three NAD‐independent isolates than in normal NAD‐dependent bacteria.ConclusionBy discovering NAD‐independent forms of A. paragallinarum, these species have a greater range than previously believed. A clear, cautious approach should be taken in diagnosing and possibly controlling IC.

The Western United States has Greater Antibiotic Resistance Among Salmonella Recovered from Intestinal Cecal Samples of Food Animals.

As part of the National Antimicrobial Resistance Monitoring System (NARMS) activities, the United States Department of Agriculture (USDA) Food Safety Inspection Service (FSIS) collected cecal samples from food animal slaughter facilities throughout the country between 2014 and 2018. Of the 26,780 cecal samples from cattle, swine, chicken and turkey , 6,350 (23.71%) tested positive for Salmonella . NARMS tested Salmonella for susceptibility to aminoglycosides, folate pathway inhibitors, macrolides, phenicols, quinolones, beta lactams, and tetracyclines. Using the regional subdivisions defined in the USDA Office of Investigation, we used chi-square test to assess potential association between the region from which the samples were collected and both Salmonella prevalence and susceptibility. The results show a significant association between region and Salmonella prevalence, when accounting for source and establishment size, with the southeast region having the highest probability of finding Salmonella . However, the western region had the highest resistance probability across all antimicrobial classes except for macrolides, which showed no regional association. This association between region and resistance was strongest among isolates from cattle. Analysis of whole-genome sequencing data indicated that a significantly higher prevalence of Salmonella Newport in cattle in the western region (accounting for 9.52% of cattle isolates, compared to 3.44% in other regions) may account for the greater resistance to multiple drug classes. Approximately 90% of Salmonella Newport in the west exhibited the MDR-AmpC phenotype encoded by aph(3'')-Ib/aph(6)-Id , bla CMY-2 , floR , sul2 , and tetA. . Thus, differences in resistance across regions may be due to geographical differences in the prevalence of specific Salmonella serotypes and their accompanying resistance genes.

Association between ward-transfers and hospital-acquired infection: a study using routine data

Abstract Ward-transfers have become more common as hospital staff balance patient needs with bed availability on specific wards. However, increased movement through the hospital may leave patients more vulnerable to potential infectious pathogen transmission routes via increased exposure to contaminated surfaces and more contacts with individuals. This may increase their risk of hospital-acquired infections (HAIs), an adverse event associated with greater antibiotic resistance, patient costs, morbidity, and mortality. This study aimed to quantify the association between the number of ward-transfers undergone during a hospital spell and the outcome of HAI. As elderly patients comprise a large proportion of hospital users and are a high-risk population for HAIs, analysis was focused on people over 65-years old. A retrospective case-control study was undertaken using data extracted from electronic health records and microbiology cultures of non-elective medical admissions to a London hospital trust between January 2016 and December 2018 (n = 24,439). Logistic regression was used to obtain the odds ratio for developing a HAI as a function of the number of ward-transfers until onset of HAI for cases, or hospital discharge for controls, while controlling for covariates including length of stay, procedures and comorbidities. Each additional ward-transfer increased the odds of developing a HAI by 8% (OR 1.08; 95%CI:1.04-1.12). The hospital is a complex environment, and interventions should be viewed in light of their impact on the system as a whole. These findings indicate that non-essential ward-transfers of elderly patients should be minimised. This may lower the incidence of infections in this population, potentially reduce the number of pathogen transmission routes in hospitals and alleviate staff burden incurred by ward-transfer associated procedures. Key messages We analysed 3 years of patient movement and microbiology data of elderly patients in a London hospital trust. Each ward-transfer increased the risk of developing a hospital-acquired infection by 8%. Reducing the number of non-essential ward-transfers patients undergo may lower the incidence of hospital-acquired infections; the decision to move a patient should therefore be carefully considered.

Paper #21 - Hemolysis is a diagnostic adjuvant for propionibacterium acnes orthopaedic shoulder infection

Introduction: Prior work has suggested that the hemolytic phenotype of Propionibacterium acnes (P. acnes) is related to the pathogenicity of this bacterium. The purpose of this study was to further evaluate orthopaedic patients with and without hemolytic strains of P. acnes. We hypothesized that patients identified with hemolytic strains of P. acnes would demonstrate a more prominent systemic inflammatory response, greater antibiotic resistance, and exhibit a higher rate of definite clinical infection than non-hemolytic strains of P. acnes.

Selective compartments and antibiotic resistance diversity

Genetic variability – which selection acts upon – is a prerequisite for every evolutionary event. Selection, such as antibiotic pressure, usually reduces the diversity of variants by favoring those that are better adapted. However, the recent study of Low et al. [1xProtected environments allow parallel evolution of a bacterial pathogen in a patient subjected to long-term antibiotic therapy. Low, A.S. et al. Mol. Microbiol. 2001; 42: 619–630Crossref | PubMed | Scopus (25)See all References[1] shows that, in the long term, antibiotic treatment might provoke the diversification of antibiotic resistance.Low et al. observed that extended antibiotic therapy in a single patient suffering from multiple liver cysts infected with Escherichia coli resulted in diversification of the antibiotic resistance. The patient was treated with different β-lactam antibiotics combined with antibiotics from other classes. After several years, E. coli isolates showed greater antibiotic resistance, partly as a consequence of mutations in the promoter region of the ampC gene leading to increased expression of the AmpC enzyme. They also encoded different β-lactamases, with different pI values. The isolates differed in their auxotrophic markers. However, molecular analysis of different isolates demonstrated that they evolved from a single founder population.It is therefore possible that a single localized infection led to a range of antibiotic-resistant lineages via parallel pathways of evolution. Infected cysts probably provided separated protected environments. Consequently, separate environments allow independent evolution of resistant bacteria. In different selective compartments, antibiotics could have reached a variety of concentrations and therefore selected for different antibiotic-resistant variants. This study provides a new insight into the origins, and the maintenance, of genetic diversity in the mechanisms involved in antibiotic resistance.

Plasmids of Pseudomonas cepacia strains of diverse origins

Thirty-seven strains of Pseudomonas cepacia from clinical, pharmaceutical-industrial, and environmental origins were analyzed for the presence of plasmid DNA by a modification of the rapid alkaline extraction method of Birnboim (H. C. Birnboim, Methods Enzymol. 100:243-255, 1983). Plasmids were present in 31 strains (84%) from all sources, with no one source showing less than 75% plasmid carriage among its strains. The plasmid profiles indicated that the presence of large plasmids (146 to 222 kb) was the norm. Those strains with greater antibiotic resistance were mainly in the clinical and pharmaceutical groups and carried large plasmids (222 kb) that appeared essentially identical by restriction digest analysis. The ability for conjugative transfer was shown with the broad-host-range plasmid R751 carrying the gene for resistance to trimethoprim, one of the few antimicrobial agents effective against P. cepacia. The plasmid was transferred from Pseudomonas aeruginosa to P. cepacia strains as well as from P. cepacia transconjugants to other P. cepacia strains.

Minimum Inhibitory Concentrations and Disk Diffusion Zone Diameter for Selected Antibiotics Against Streptococci Isolated from Bovine Intramammary Infections

The antimicrobial susceptibility to 11 antibiotics was determined of 358 streptococcal isolates representing six species was determined. All isolates were from milk samples obtained from clinical or subclinical cases of bovine mastitis. Agar disk diffusion zone diameters and minimum inhibitory concentrations were obtained for all isolates. Of the antibiotics tested that are available for mastitis therapy, cephalothin, penicillin, ampicillin, novobiocin, and erythromycin demonstrated acceptable activity against nonenterococcal streptococci, but only penicillin and ampicillin demonstrated moderate activity against Enterococcus faecalis. Enterococcus faecalis demonstrated substantial resistance to cephalothin, erythromycin, gentamicin, streptomycin, and tetracycline, while the nonenterococcal streptococci demonstrated substantial resistance to gentamicin, streptomycin, and tetracycline. Streptococcus uberis demonstrated greater antibiotic resistance than did Streptococcus dysgalactiae, while Aerococcus viridans demonstrated the greatest overall resistance of the nonenterococcal species.

Klebsiella capsular type versus site of isolation.

More than 1750 clinical isolates of klebsiella were collected over a period of six years from two different hospitals and capsular typed by the fluorescent antibody technique. A correlation was made between type and site of isolation. Many types were found to be associated more frequently with one site, which suggested a predilection of some capsular types for certain sites of infection. The site may also be a factor contributing to the virulence of a particular type. A greater antibiotic resistance was often noted in types isolated from their predominant sites; however, antibiograms were not consistent for a type from a given site. The combination of site specificity, resistance, and another 'virulence factor' may all be involved in the determination of a pathogenic strain.