Common Gram-negative Bacteria Research Articles

Effects of the COVID-19 Pandemic on Microbial Keratitis: A 5-Year Comparative Study.

To report the clinical and microbiological profiles of microbial keratitis and its antimicrobial resistance before, during, and after COVID-19. This was a retrospective case-note review of all corneal scrape specimens collected from patients with microbial keratitis from January 2018 to December 2023. Case records were analyzed for demographic characteristics, microbiological diagnosis, and antibiograms. All outcome variables were collected, stratified, and compared between 3 periods: the pre-COVID-19 group (January-December 2019), the COVID-19 group (January 2020-December 2022), and the post-COVID-19 group (January-December 2023). A total of 947 corneal cultures from 947 patients were reviewed. Gram-positive bacteria predominated in all periods, with no significant differences in their distribution. Staphylococcus epidermidis was the most frequently identified organism. Pseudomonas aeruginosa was the most common Gram-negative bacterium, with its incidence significantly lower in the post-COVID period. Fungal infections showed a significant increase in the post-COVID group, with Fusarium sp. being the most common fungus and showing a significant increase in incidence in the post-COVID group. Despite a stable incidence of microbial keratitis, this study highlights a concerning trend in antibiotic resistance. Although some pathogens became less common, those that persisted have become increasingly difficult to treat. Understanding the clinical and microbiological profiles of microbial keratitis and antimicrobial resistance patterns before and after the COVID-19 pandemic is crucial for informed treatment decisions.

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

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

Bacteriological Profile and Antibiotic Susceptibility of Neonatal Sepsis Cases in the Neonatal Intensive Care Unit of a Tertiary Hospital in Türkiye

Objective: We aimed to determine the demographic data, mortality, and morbidity of early- and late-neonatal sepsis cases, the etiologic agents in these cases, and the antibiotic susceptibility of these agents. Methods: This study was conducted retrospectively in a tertiary neonatal intensive care unit (NICU). The demographic, clinical, and laboratory data of newborns diagnosed with culture-proven sepsis within 24 months were evaluated. Results: Two hundred and eleven culture data points belonging to 197 infants were evaluated. Forty percent of the infants had a history of premature birth. The most common clinical findings were respiratory distress and feeding intolerance. Coagulase-negative staphylococci (CoNS) were detected most frequently as early- and late-sepsis agents. The most common Gram-negative bacteria detected as late-sepsis agents were Klebsiella spp. and Escherichia coli (E. coli). The overall mortality rate was 10%. Conclusion: Neonatal sepsis continues to have high mortality rates in tertiary NICUs. CoNS was the most common agent, highlighting the importance of developing and maintaining personnel training and handwashing practices. It will be important to consider the resistance rates of Klebsiella spp., the most common Gram-negative agent in late-onset sepsis (LOS) cases, to commonly used antibiotics in empirical treatments.

The effect of selenium on the intestinal health of juvenile grass carp based on the ERS-autophagy pathway

Selenium (Se), a trace element, is vital for the maintenance of cellular redox balance, thyroid hormone metabolism, inflammation, and immunity. Aeromonas hydrophila (A. hydrophila) is a common Gram-negative conditional pathogenic bacterium in fish culture, posing a serious threat to intensive aquaculture. Our study investigated the influence of dietary Se on the intestinal immune function of grass carp (Ctenopharyngodon idella) and the related regulatory mechanisms. The 2160 healthy juvenile grass carp (9.76 ± 0.005 g) were randomly assigned to 6 test groups of 6 replicates each, and fed graded selenomethionine (0.05, 0.20, 0.40, 0.61, 0.77, 0.98 mg Se/kg diet) for 70 days and then injected with A. hydrophila for a 6-day attack test. The results indicated that appropriate Se levels (0.40 mg/kg diet) alleviated intestinal damage caused by A. hydrophila and increased intestinal immune substances C3 and C4 levels as well as the activity of acid phosphatase (ACP) and lysozyme (LZ) (P > 0.05). Appropriate levels of Se (0.40 mg/kg-0.61 mg/kg diet) decreased intestinal pro-inflammatory cytokines (IFN-γ2, IL-6, IL-12p35, IL-17 A F and IL-17D) mRNA levels (P > 0.05) and increased intestinal anti-inflammatory factors (TGF-β1, IL-4/13A, IL-4/13B, IL-10 and IL-22) mRNA levels (P > 0.05) in juvenile grass carp. Further studies revealed that Se (0.40 mg/kg-0.61 mg/kg diet) inhibited intestinal endoplasmic reticulum stress (ERS)-related signaling pathway. Furthermore, we found that appropriate levels of Se (0.40 mg/kg-0.61 mg/kg diet) inhibited intestinal autophagy in juvenile grass carp, which may be related to ULK1, Beclin 1, ATG5, ATG12, LC3, and P62. In conclusion, appropriate levels of Se can alleviate intestinal inflammation and inhibit ERS and autophagy in juvenile grass carp. A quadratic regression analysis of intestinal ACP and LZ also indicated that the Se requirements of juvenile grass carp were 0.59 and 0.51 mg/kg, respectively.

Clinical and Microbiological Profile of Gram-Negative Infections in Critically Ill Diabetic Patients.

Background and aim Type 2 diabetes mellitus (T2DM) is associated with several infections due to hyperglycemia and impaired immunity. This study aims to analyze the clinical and microbiological profile of critically ill T2DM patients with sepsis due to gram-negative bacteria (GNB). Materials and methods A prospective cross-sectional observational study was conducted at Dr. D. Y. Patil Medical College, Hospital & Research Centre, Pune, India, between December 2023 and May 2024, after ethics committee approval. A total of 100 patients (50 T2DM cases and 50 nondiabetic controls), diagnosed with sepsis due to GNB and admitted to the medical ICU, were included in the study. The clinical profile and laboratory investigations of these patients were studied. Cultures were obtained from peripheral/central venous samples, tracheal secretions, and urine samples. Cultures from other specimens, such as ascitic fluid, cerebrospinal fluid, and pus from skin and soft tissue infections, were also obtained. The statistical tests that were applied were two-tailed with a 95% CI, and a p-value of less than 0.05 was considered statistically significant. Results The mean age of critically ill T2DM cases was 60.52 ± 12.88 years. Of the 50 T2DM cases, 28 were males and 22 were females. The most common infection in critically ill T2DM patients was bloodstream infection (n = 21), followed by bronchopneumonia (n = 16) and urinary tract infections (n = 10). Escherichia coli (n = 15) and Klebsiella pneumoniae (n = 15) were the most common gram-negative pathogens isolated. The most common GNB isolated from the blood cultures of critically ill T2DM patients was Acinetobacter spp. (n = 6). The death rate was significantly higher in T2DM patients with GNB sepsis as compared to nondiabetic controls. Conclusion GNBs like E. coli, K. pneumoniae, and Acinetobacter spp. are commonly found in critically ill T2DM patients with sepsis. Bloodstream infection was the most common site of infection in critically ill T2DM cases. Acinetobacter spp. was the most common isolate found in the blood cultures of critically ill T2DM patients. It is important to identify the site of sepsis, isolate the organism, and treat it with appropriate antibiotics promptly in critically ill T2DM patients to improve the outcomes of these patients.

Bacteriological Profile and Antibiogram of Lower Respiratory Tract Infection (LRTI) in a Tertiary Teaching Hospital of Bangladesh

Introduction: Lower respiratory tract infection (LRTI) is one of the common infectious diseases in the world especially in the developing countries. This causes a large financial burden to healthcare system too. Methodology: This was a cross-sectional descriptive study to find out the infection patter and antibiogram of sputum of LRTI patients. Study place was Sylhet Women’s Medical College Hospital. Study period was 6 months. Sample size 684. Results: This positive samples were 60.4% of all the samples. Male and female percentage were 61.1% and 38.9% respectively. The age of the nearly half (49.56%) of the participants were 60 years or above. Commonest isolated Gram-positive bacteria was Staphylococcus aureus (37.87%) and commonest Gram-negative bacteria was Klbsiellaspp (23.39%). Commonest sensitive antibiotics were Piperacillin &amp; Tazobactam (93.86%), Imipenem (93.71%) and Meropenem (90.64%). Conclusion: Use of proper antibiotic is essential to prevent antibiotic resistance. Institutional and regional antibiogram can help in decision making for selecting empirical antibiotic.

Antibiotic Sensitivity and Biofilm Formation in Pseudomonas aeruginosa Isolated from Wound Infections in Baghdad City

Pseudomonas aeruginosa is considered as the most common gram-negative bacteria that infect hospitalized patients. One hundred sixty six specimens of wound discharge were collected during the period from October to December 2022. Thirty isolates of Pseudomonas aeruginosa have been identified via the cultural, morphological, and biochemical tests. Vitek-2 compact system used to determine the most accurate identification for Pseudomonas aeruginosa, and thirty isolates of Pseudomonas aeruginosa were recognized. In the present study, Pseudomonas aeruginosa was detected in 32.25% of the isolates. All isolates were subjected to antibiotic susceptibility tests to determine their susceptibility to 14 different antibiotics. The results showed total resistance to piperacillin (100%), high resistance rates to ceftazidime (96.7%), tobramycin (96.7%), gentamicin (80%), piperacillin-tazobactam (70%), aztreonam (66.7%), cefoperazone (66.7%), and amikacin (60%). Low resistance rates were found for imipenem (30%), meropenem (43.3%), and gatifloxacin (46.7%), but there was moderate resistance to ciprofloxacin (53.3%), cefotaxime (50%) and colistin (50%). The current investigation determined that among 30 isolates of Pseudomonas aeruginosa, six (20%) developed a weak biofilm, nine (30%) formed a moderate biofilm, and fifteen (50%) formed a strong biofilm. The findings of the present investigation revealed that the vast majority of the isolates with significant antibiotic-resistance can create biofilms.

Dynamic immune status analysis of peripheral blood mononuclear cells in patients with Klebsiella pneumoniae bloodstream infection sepsis using single-cell RNA sequencing.

Klebsiella pneumoniae is a common Gram-negative bacterium. Blood infection caused by K. pneumoniae is one of the most common causes of human sepsis, which seriously threatens the life of patients. The immune status of peripheral blood mononuclear cells (PBMCs) based on single-cell RNA sequencing (scRNA-seq) in acute stage and recovery stage of sepsis caused by K. pneumoniae bloodstream infection has not been studied. A total of 13 subjects were included in this study, 3 healthy controls, 7 patients with K. pneumoniae bloodstream infection in the acute stage (4 patients died), and 3 patients in the recovery stage. Peripheral blood of all patients was collected and PBMCs were isolated for scRNA-seq analysis. We studied the changes of PBMCs components, signaling pathways, differential genes, and cytokines in acute and recovery stages. During K. pneumoniae acute infection we observed a decrease in the proportion of T cells, most probably due to apoptosis and the function of T cell subtypes was disorder. The proportion of monocytes increased in acute stage. Although genes related to their phagocytosis function were upregulated, their antigen presentation capacity-associated genes were downregulated. The expression of IL-1β, IL-18, IFNGR1 and IFNGR2 genes was also increased in monocytes. The proportion of DCs was depleted during the acute stage and did not recover during sepsis recovery. DCs antigen presentation was weakened during the acute stage but recovered fast during the recovery stage. pDCs response to MCP-1 chemokine was weakened, they recovered it quickly during the recovery stage. B cells showed apoptosis both in the acute stage and recovery stage. Their response to complement was weakened, but their antigen presentation function was enhanced. The proportion of NK cells stable during all disease's stages, and the expression of IFN-γ gene was upregulated. The proportion of PBMCs and their immune functions undergo variations throughout the course of the disease, spanning from the acute stage to recovery. These findings provide new insights into the mechanism of PBMCs immune function during K. pneumoniae bloodstream infection sepsis and recovery and sets the basis for further understanding and treatment.

Glaesserella parasuis serotype 5 induces pyroptosis via the RIG-I/MAVS/NLRP3 pathway in swine tracheal epithelial cells

Glaesserella parasuis (G. parasuis) is a common Gram-negative commensal bacterium in the upper respiratory tract of swine that can cause Glässer's disease under stress conditions. Pyroptosis is an important immune defence mechanism of the body that plays a crucial role in clearing pathogen infections and endogenous danger signals. This study aimed to investigate the mechanism of G. parasuis serotype 5 SQ (GPS5-SQ)-induced pyroptosis in swine tracheal epithelial cells (STECs). The results of the present study demonstrated that GPS5-SQ infection induces pyroptosis in STECs by enhancing the protein level of the N-terminal domain of gasdermin D (GSDMD-N) and activating the NOD-like receptor protein 3 (NLRP3) inflammasome. Furthermore, the levels of pyroptosis-related proteins, including GSDMD-N and cleaved caspase-1 were considerably decreased in STECs after the knockdown of retinoic acid inducible gene-I (RIG-I) and mitochondrial antiviral signaling protein (MAVS). These results indicated that GPS5-SQ might trigger pyroptosis through the activation of the RIG-I/MAVS/NLRP3 signaling pathway. More importantly, the reactive oxygen species (ROS) scavenger N-acetylcysteine (NAC) repressed the activation of the RIG-I/MAVS/NLRP3 signaling and rescued the decrease in Occludin and zonula occludens-1 (ZO-1) after GPS5-SQ infection. Overall, our findings show that GPS5-SQ can activate RIG-I/MAVS/NLRP3 signaling and destroy the integrity of the epithelial barrier by inducing ROS generation in STECs, shedding new light on G. parasuis pathogenesis.

Pathogenic spectrum and risk factors of peritoneal dialysis-associated peritonitis: a single-center retrospective study

The present study aimed to explore the pathogenic spectrum and risk factors of peritoneal dialysis-associated peritonitis (Peritoneal dialysis associated peritonitis, PDAP) in Yongzhou, Hunan, China. The clinical and epidemiological data on regular peritoneal dialysis (Peritoneal dialysis, PD) between January 2016 and December 2020 in Yongzhou were collected for retrospective analysis. The related factors of peritonitis were evaluated by single-factor analysis, while risk factors of refractory PDAP were evaluated by multivariate logistic regression analysis.172/331 172 (51.9%) patients developed peritonitis. The risk factors of PDAP in PD patients included high C-reactive protein (C-reactive protein, CRP), low albumin(Albumin, ALB), low hemoglobin (Hemoglobin, Hb), low educational level (junior high school or lower), preference of spicy food, irregular diet, low annual household income, unfavorable fluid exchange conditions, unstable employment (including working as a farmer), and unfavorable humidity conditions (P < 0.05). 63/172 (36.6%) PDAP patients were intractable cases with a pathogenic bacteria positive rate of 74.60% in the peritoneal dialysate cultures, and 109/172 patients were non-intractable cases with a pathogenic bacteria positive rate of 53.21%. Gram-positive bacteria (G+) were detected in most of the dialysate cultures, with Staphylococcus epidermidis (S. epidermidis) as the most common type, while Escherichia coli (E. coli) was the most common Gram-negative bacteria (G-). Gram-positive bacteria were sensitive to vancomycin and linezolid, while G- bacteria were sensitive to imipenem and amikacin. Lifestyle, educational level, and environmental factors are the major contributors to PDAP in PD patients. Fungal and multi-bacterial infections are the major causes of death; PD is stopped for such patients.

On the Microstructure and Dynamics of Membranes Formed by Lipid as From Stenotrophomonas maltophilia, a Member of Gut Microbiome: An EPR Study

AbstractLipid As are the main components of the external leaflet of the outer membrane of Gram-negative bacteria. Their molecular structure has evolved to allow the bacteria survival in specific environments. In the present work, we investigate how and to what extent lipid membranes that include in their composition lipid A molecules of a bacterium of the gut microbiota, Stenotrophomonas maltophilia, differ from those formed by the lipid A of the common Gram-negative bacterium Salmonella enterica, which is not specific to the gut and is here used as a reference. Electron Paramagnetic Resonance (EPR) spectroscopy, using spin-labelled lipids as molecular probes, allows the segmental order of the acyl chain and the polarity across the bilayer to be analyzed in detail. Both considered lipid As cause a stiffening of the outermost segments of the acyl chains. This effect increases with increasing the lipid A content and is stronger for the lipid A extracted from Stenotrophomonas maltophilia than for that extracted from Salmonella enterica. At the same time, the local polarity of the bilayer region just below the interface increases. As the inner core of the bilayer is considered, it is found that the lipid A from Salmonella enterica causes a local disorder and a significant reduction of the local polarity, an effect not found for the lipid A from Stenotrophomonas maltophilia. These results are interpreted in terms of the different lengths and distributions of the acyl tails in the two lipid As. It can be concluded that the symmetrically distributed short tails of the lipid A from Stenotrophomonas maltophilia favors a regular packing within the bilayer.

Bacterial etiology and antimicrobial resistance pattern of pediatric bloodstream infections: a 5-year experience in an Iranian referral hospital

BackgroundBloodstream infections (BSI) are the major cause of morbidity and mortality in children in developing countries. The purpose of the current study was to establish the antimicrobial susceptibility pattern of bacterial isolates from bloodstream infections at Children’s Medical Center Hospital (CMC), Tehran, Iran.MethodsWe retrospectively recorded all positive blood cultures and antimicrobial susceptibility of all bloodstream isolates among children admitted to CMC, during 5 years. Specimen culture, bacterial identification, and antimicrobial susceptibility testing were performed according to standard laboratory methods.ResultsFrom 3,179 pathogens isolated from the blood cultures 2,824 bacteria were cultured, with 1,312 cases being identified as Gram-positive bacteria (46%) and 1,512 cases as Gram-negative bacteria (54%). The most common Gram-negative bacteria isolated were as follows: Pseudomonas spp. (n = 266, 17.6%), Klebsiella pneumoniae (n = 242, 16%), Stenotrophomonas maltophilia (n = 204, 13.5%), Enterobacter spp. (n = 164, 10.8%), Escherichia coli (n = 159, 10.5%), Pseudomonas aeruginosa (n = 126, 8.3%), Serratia marcescens (n = 121, 8%), and Acinetobacter baumannii (n = 73, 4.8%). The most common Gram-positive bacteria isolated were coagulase-negative staphylococci (CONS) (n = 697, 53%), Streptococcus spp. (n = 237, 18%), Staphylococcus aureus (n = 202, 15%) and Enterococcus spp. (n = 167, 12.7%). 34% of bacterial strains were isolated from ICUs. The rates of methicillin resistance in S. aureus and CONS were 34% and 91%, respectively. E. coli isolates showed high resistance to cefotaxime (84%). All isolates of K. pneumoniae were susceptible to colistin and 56% were susceptible to imipenem. P. aeruginosa isolates showed high susceptibility to all antibiotics.ConclusionsOur findings emphasize the need of clinicians having access to up-to-date bacterial susceptibility data for routinely prescribed drugs. Continuous monitoring of changes in bacterial resistance will aid in the establishment of national priorities for local intervention initiatives in Iran. The increased risk of BSI caused by antibiotic-resistant organisms, emphasizes the significance of implementing appropriate antibiotic prescribing regulations and developing innovative vaccination techniques in Iran.

Tracking the Phylogenetic Origins of Proteus mirabilis and P. vulgaris in Iraq

Abstract Background: Common gram-negative rod-shaped bacteria called Proteus spp. are widely known for their swarming motility and urease activity. It is the main pathogen that causes complicated urethral tract infections. Objectives: Proteus mirabilis and P. vulgaris isolates were isolated, and the positions of the bla TEM, bla CTX-M, and bla SHV genes on the P. mirabilis isolates’ genomes were identified. The MEGA X10.2.4 software tool was employed to achieve this, and the genetic trees of P. mirabilis were created. Additionally, the isolates that represent the prevalence and degree of pathogenicity of these bacteria in Iraq were used to produce biofilms. Materials and Methods: A total of 210 urine samples from various patients who were hospitalized in general hospitals in Iraq between September 2021 and July 2022 were collected and yielded forty isolates of P. mirabilis and P. vulgaris. Traditional methods and the VITEK 2 compact were used to identify the isolates, which were given the names PM1 to PV40. Results: The results showed that all isolates were biofilm-forming, with the following ratios: 5 (15%) were weak, 31 (5.77%) were medium, and 4 (5.7%) were strong. The matching of this study isolates with NCBI-Gen bank global strains found that four isolates (PM1, PM2, PM3, and PM4) were originated in India, two isolates (PM5 and PM8) were originated in Iraq, and one (PM6) isolate was originated in Egypt. Conclusion: According to the results of this investigation, P. mirabilis and P. vulgaris isolates from various geographical areas show varying degrees of virulence factors. Therefore, additional researches are required to create a genetic diversity map of P. mirabilis and P. vulgaris due to variable frequencies in the sequencing of bla TEM, bla CTX-M, and bla SHV genes of the isolates.

Bioaerosol Emission from Vortex Liquids Contaminated with Escherichia coli Bacteria

Vortex fluids are often present in natural and artificial aquatic environments and are also widely used in industrial water treatment and product manufacturing processes. Vortex processes have been studied quite extensively; however, little attention has been paid to the potential release of biological aerosols to the ambient air in common situations involving microbial-contaminated vortex liquids. The model organism was Escherichia coli, a common Gram-negative coliform bacterium widely present in the aquatic and air environments. This study examines the influence of various parameters, including liquid rotation speed, column height, temperature, surface tension and vessel size, on the rate of bioaerosol formation. A commonly used single-stage bioaerosol impactor was employed to collect microbial aerosols at different process parameters under controlled laboratory conditions. The main results show that bioaerosol production increases markedly with increasing rotation speed, reaching a maximum rate at the highest value used in this project (1300 rpm). The tallness of the liquid column is strongly responsible for the bioaerosol production efficiency reaching a difference of almost one order of magnitude along the range between 45 mm (highest bioaerosol release) and 110 mm used in this research. Fluid temperature and surface tension are also very influential parameters responsible for bioaerosol generation during fluid vortex motion; corresponding results are discussed in this manuscript.

Spectrum and antibiotic sensitivity of bacterial keratitis: a retrospective analysis of eight years in a Tertiary Referral Hospital in Southwest China.

The objective of this study was to investigate the epidemiological characteristics, distribution of isolates, prevailing patterns, and antibiotic susceptibility of bacterial keratitis (BK) in a Tertiary Referral Hospital located in Southwest China. A retrospective analysis was conducted on 660 cases of bacterial keratitis occurring between January 2015 and December 2022. The demographic data, predisposing factors, microbial findings, and antibiotic sensitivity profiles were examined. Corneal trauma emerged as the most prevalent predisposing factor, accounting for 37.1% of cases. Among these cases, bacterial culture results were positive in 318 cases, 68 species of bacteria were identified. The most common Gram-Positive bacteria isolated overall was the staphylococcus epidermis and the most common Gram-Negative bacteria isolated was Pseudomonas aeruginosa. Methicillin-Resistant Staphylococci accounted for 18.1% of all Gram-Positive bacteria. The detection rate of P. aeruginosa showed an increasing trend over time (Rs=0.738, P=0.037). There was a significant decrease in the percentage of Gram-Negative microorganisms over time (Rs=0.743, P=0.035). The sensitivity of Gram-Positive bacteria to linezolid, vancomycin, tigecycline, quinupristin/dalfopristin, and rifampicin was over 98%. The sensitivity rates of Gram-Negative bacteria to amikacin, meropenem, piperacillin/tazobactam, cefoperazone sodium/sulbactam, ceftazidime, and cefepime were all above 85%. In patients with a history of vegetative trauma, the possibility of BK should be taken into account in addition to the focus on fungal keratitis. The microbial composition primarily consists of Gram-Positive cocci and Gram-Negative bacilli. Among the Gram-Positive bacteria, S. epidermidis and Streptococcus pneumoniae are the most frequently encountered, while P. aeruginosa is the predominant Gram-Negative bacteria. To combat Gram-Positive bacteria, vancomycin, linezolid, and rifampicin are considered excellent antimicrobial agents. When targeting Gram-Negative pathogens, third-generation cephalosporins exhibit superior sensitivity compared to first and second-generation counterparts. As an initial empirical treatment for severe cases of bacterial keratitis and those unresponsive to fourth-generation fluoroquinolones in community settings, the combination therapy of vancomycin and tobramycin is a justifiable approach. Bacterial keratitis can be better managed by understanding the local etiology and antibacterial drug susceptibility patterns.

Epidemiologic analysis of antimicrobial resistance in hospital departments in China from 2022 to 2023

Bacterial drug resistance monitoring in hospitals is a crucial aspect of healthcare management and a growing concern worldwide. In this study, we analysed the bacterial drug resistance surveillance in our hospital from 2022 Q1 to 2023 Q2. The main sampling sources were respiratory, blood, and urine-based, and the main clinical infections were respiratory and genitourinary in nature. Specimens were inoculated and cultured; bacterial strains were isolated using a VITEK® 2 Compact 60-card automatic microorganism identifier (bioMerieux, Paris, France) and their matching identification cards were identified, and manual tests were supplemented for strain identification. The most common Gram-positive bacteria detected were Staphylococcus aureus, followed by Enterococcus faecalis (E. faecalis), Staphylococcus epidermidis (S. epidermidis), and Staphylococcus haemolyticus (S. haemolyticus). The most common Gram-negative bacteria detected were Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The most prevalent multidrug-resistant bacteria were those producing extended-spectrum beta-lactamases, followed by methicillin-resistant Staphylococcus aureus, followed by carbapenem-resistant Enterobacterales. This study suggests that the prevention and control of infections in the respiratory and genitourinary systems should be the focus of anti-infective work and that the use of antimicrobials should be reduced and regulated to prevent the emergence and spread of resistant bacteria.

Study the Phenotypic and Antimicrobial Susceptibility of Pseudomonas aeruginosa Isolated Clinically from Baghdad Hospitals

Pseudomonas aeruginosa, is negative to gram stain, take the rod shape and considered as strictly aerobic. the most affect bacteria in nosocomial infection. P.aeruginosa is an opportunistic pathogen bacterium that can made serious infections in human who are immune compromised, such as urinary tract infection, skin and ear infection, and others. One hundred twenty one sample were taken from patients in different sites of infections (ear, wound, UTI , burn) from AL-Yarmouk, Ghazi Al-Hariri hospitals in Baghdad during the period from November 2016 to February 2017. Fifty seven isolates were diagnoses as P. aeruginosa by characteristic in culture media, tests and API 20E. forty isolates involved in our study ten from each source. Antibiotic susceptibility test performed for forty clinically isolates of P. aeruginosa by the disk diffusion method against some antibiotics belong to different group and the results revealed that bacteria is multi-drug resistance (MRD) as well, revealed the most compound that have activity against Pseudomonas. aeruginosa were Imipenem, Pipracillin, and Ceftazidime. Biofilms are currently estimated and the P. aeruginosa reflect high ability to produce biofilm. All isolates used in this study formed biofilm with differences in thickness of formed layer. In this study, we concluded P. aeruginosa is one of the most common gram-negative bacteria involved in hospital infections causing opportunistic infection because they have intrinsically and acquired resistant to a number of antimicrobial agents and produces a number of exoproducts which are implicated in the pathogenesis of P. aeruginosa infections.

Evaluation to Determine Antibiotic Resistance Reduction in Gram-Negative Bacteria from 2019 to 2021 by the Saudi Arabia National Plan.

The main objective of this study was to investigate the three-year evaluation of antibiotic resistance (AR) of multi-drug-resistant organisms and extended-spectrum beta-lactamase (ESBL)-resistant rate of gram-negative bacteria in one of the largest hospitals by the Saudi Arabia Nation Plan. This study was conducted in the Department of Laboratory Medicine, in a private hospital in Riyadh City, Saudi Arabia, from January 2019 to December 2021 in 120-bed private hospitals. A total of 4700 gram-negative isolated organisms were obtained from the various specimens of the patients, and antibiotic sensitivity tests were performed. According to the manufacturer's instructions, the inoculum prepared was applied to two test cards, one for the identification system VITEK 2 ID-GNB and another for susceptibility testing antimicrobial susceptibility testing (AST) No. 12. The most common gram-negative bacteria isolated was Escherichia coli (2706/4700; 57.57%), followed by Klebsiella pneumoniae (905/4700; 19.25%) and Pseudomonas aeruginosa (395/4700; 8.40%). Escherichia coli's highest AR reduction was reported for cefotaxime (CTX) of 29% (295/1018; 29%, 172/818; 21%, 0/870; 0%) for 2019, 2020, and 2021, respectively. Except for Salmonella species, which displayed enhanced AR, the ESBL and multidrug-resistant (MDR) rates decreased significantly (p 0.05) for most bacteria. This study helps to understand the maximum number of gram-negative bacteria susceptible to the Saudi National Action Plan (SNAP) to decrease the prevalence of AR, ESBL, and MDR. To comprehensively understand SNAP's effectiveness, other trials involving gram-positive bacteria should be considered.

The epidemiology and the pathogen distribution of pediatric dacryocystitis in Chinese population 2017–2022

BackgroundDacryocystitis is a common disease in pediatric ophthalmology. Analysis of basic information, flora distribution, and characteristics of information on drug-resistant bacteria in children with dacryocystitis for 6 years, providing evidence for ophthalmologic infection prevention and clinical management strategies.MethodsA retrospective cohort study was conducted to evaluate the demographics of dacryocystitis in children and microbiological characteristics of secretion cultures, and to analyze the basic information, distribution of pathogenic bacteria, drug resistance, and to plot trendsand distribution pie charts according to the years.ResultsThis study recruited 5791 specimens. Decreased incidence of dacryocystitis from 2020 to 2022 (including the COVID-19 pandemic). The age of highest incidence of dacryocystitis is infancy, followed by the neonatal period, and the incidence decreased with age. Streptococcus pneumoniae had the highest percentage in 2017, and the overall trend was decreasing, the difference was statistically significant (p < 0.001); Streptococcus mitis showed an overall increasing trend, with the highest incidence in 2022 and the lowest in 2017, with a statistically significant difference (p < 0.001); Haemophilus influenzae was the most common gram-negative bacteria with an overall decreasing trend (p < 0.001); The incidence of Catamoeba and Stenotrophomonas varied from year to year, with statistically significant differences (p = 0.010, p = 0.033, respectively). Methicillin-resistant Staphylococcus aureus (MRSA) had the lowest incidence in 2017 and 2022 the highest incidence in 2022, with a statistically significant difference in incidence between years (p = 0.003); β-lactamase-positive was the most common type of resistance, and MRSA was the second, with statistically significant differences between years (p = 0.003, p < 0.001, respectively). Streptococcus pneumoniae is a common etiologic agent of dacryocystitis in all age groups.ConclusionsDacryocystitis in children is significantly associated with age characteristics and infection-related pathogens, and infection prevention and control can help reduce the infection of related pathogens and the increase of new drug-resistant strains. Close monitoring of changes in pathogen distribution in ocular secretion cultures can help in early intervention and treatment of infectious dacryocystitis.

Establishment of portable Pseudomonas aeruginosa detection platform based on one-tube CRISPR/Cas12a combined with recombinase polymerase amplification technology

Pseudomonas aeruginosa, a common Gram-negative bacterium, is associated with diverse diseases. Its increasing resistance to antibiotics presents challenges in clinical treatment. The predominant diagnostic approach involves conventional biochemical cultures, known for their time and labor intensiveness. Despite progress in isothermal amplification studies, limitations persist, including reliance on specialized equipment, intricate primer design, and aerosol contamination. Therefore, there is a demand for enhanced clinical assays. This study successfully combined RPA and CRISPR/Cas12a techniques. Through a series of experiments involving the design and screening of lasB crRNA, the creation of lasB RPA primers, and the establishment of a streamlined RPA-CRISPR/Cas12a assay, the study developed a one-tube detection method targeting P. aeruginosa's lasB gene. The assay demonstrated inclusive behavior across standard and 21 isolates, while specifically discerning P. aeruginosa from diverse strains. Sensitivity reached 15.9 CFU/reaction. Clinical validation revealed a 97.62% concordance with traditional methods. The one-tube assay's protocol mitigated aerosol contamination. Offering precision, specificity, and sensitivity, this method shows promise for field applications in resource-scarce regions, enabling early detection and improved management of P. aeruginosa infections.