VITEK-2 Compact System Research Articles

Clinical Practice: Estimating the Breakpoints for EUCAST Fast Antimicrobial Susceptibility Testing Using Flagged BacT/Alert Blood Culture Bottles

<i>Introduction</i>: The escalating prevalence of multidrug resistance is a global threat to human health particularly in critically ill patients with bloodstream infections (BSIs). Delay in the administration of the appropriate antimicrobial treatment is associated with higher mortality rates and adverse consequences. This study attempted to estimate the rapid antimicrobial susceptibility testing (RAST) breakpoints directly from flagged BacT/Alert blood culture bottles in clinical practice. <i>Material & Methods</i>: A descriptive, cross-sectional study conducted at a tertiary care hospital in Delhi over a period of two months. The RAST was performed directly from the clinical samples for blood cultures received in our laboratory in parallel with the routine antimicrobial testing as per standard CLSI guidelines. Blood cultures were routinely incubated in BacT/Alert 3D. The inhibition zones were read at 4, 6, 8 and 16-20 hour of incubation as per European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. The identification of the isolates was confirmed by Vitek-2 compact system. <i>Results</i>: In our study, the area of technical uncertainty (ATU) percentage was initially high at 4 hours but decreased significantly in later incubation periods. At 4 hours, none of the <i>S. aureus</i> isolates showed >90% categorical agreement (CA) for any antimicrobial tested. However, clindamycin achieved the highest CA (100%) at 6 hours and 90% thereafter, with no very major errors (VME) or major error (ME). Cefoxitin required 8 hours to reach >90% CA, with no VME observed at any time point, but up to 75% ME at 8 hours. At 4 hours, most antimicrobials had high (>1.5%) rates of VME among <i>Enterobacteriales</i>. By 6 hours, only Meropenem and Gentamicin had >90% CA, with no VME observed for other antibiotics. <i>Conclusion</i>: The RAST method is relatively easy to implement in clinical microbiology labs, offering cost-effectiveness, simplicity, and rapid results, especially in resource-limited settings. However, reporting RAST results can be complex due to potential challenges with CA, VME, and ME, particularly in the initial hours of incubation and within the ATU.

Characterization of Candida species isolated from clinical specimens: insights into virulence traits, antifungal resistance and molecular profiles

BackgroundCandida species have emerged as a significant cause of opportunistic infections. Alongside the expression of various virulence factors, the rise of antifungal resistance among Candida species presents a considerable clinical challenge.AimThis study aimed to identify different Candida species isolated from clinical specimens, evaluate their antifungal sensitivity patterns, identify key genes regulating virulence mechanisms using multiplex PCR and to assess any correlation between their virulence profiles and antifungal resistance patterns.MethodA total of 100 Candida spp. was isolated from 630 different clinical specimens and identified to the species level. Their antifungal susceptibility was phenotypically evaluated in accordance with CLSI guidelines using the Vitek-2 Compact System. Virulence markers, including biofilm formation capacity, protease production, melanin production, coagulase production and hemolysin production, were also phenotypically detected. The genetic determinants for biofilm formation and extracellular hydrolytic enzymes were assessed using a multiplex PCR assay.ResultsThe prevalence of Candida spp. was 15.9%, with C. albicans (48%) and C. glabrata (16%) being the most common. C. albicans showed the highest virulence, with strong biofilm formation, and high proteinase and melanin production. Multiplex PCR revealed Hlp in 22.0%, Hwp in 80.0%, Als in 56.0%, and Sap genes in 56.0% of isolates. Virulence genes were more common in C. albicans than in non-albicans Candida (NAC). Resistance patterns significantly correlated with virulence profiles, with notable associations between flucytosine resistance and the presence of Hlp and Hwp genes.ConclusionThe significant correlation between virulent markers such as germination, coagulase, hemolysin production and resistance patterns among different Candida isolates is crucial for predicting the severity and outcomes of Candida infections. This understanding aids in guiding tailored treatment strategies.

Prevalence and Antimicrobial Susceptibility Patterns of Wound and Pus Bacterial Pathogens at a Tertiary Care Hospital in Central Riyadh, Saudi Arabia

The long history and extensive use of antibiotics have caused resistant bacterial pathogens to emerge, increasing mortality and morbidity. The current study was designed to see the prevalence of aerobic bacterial isolates with their antimicrobial resistance pattern from out- and inpatients requested for wound or pus culture. Retrospective study conducted at a tertiary care hospital in central Riyadh from January 2023 to December 2023. Samples were collected and inoculated onto the appropriate media following standard guidelines. Bacterial pathogens were identified by the Vitek2 compact system. Antimicrobial susceptibility was tested using the Kirby–Bauer disk diffusion method as well as by MIC determination through the Vitek2 compact. A total of 1186 subjects were included in the study with a bacterial isolation rate of 691 (58.3%). Out of these, 155 positive cultures had incomplete information or anaerobic or fungal growth and were excluded from the study. With a slight female predominance (54.9%), the majority of subjects (72.2%) were outpatients, and over half of the isolates (55.2%) were Gram-positive. The most common isolate was Staphylococcus spp. (44.4%), followed by E. coli (13.6%) and P. aeruginosa (12.9%). The highest resistance was reported against penicillin followed by fusidic acid against Gram-positive bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in 40.5% of Staphylococcus aureus (S. aureus) isolates. Amikacin was the most susceptible antibiotic against all Gram-negative isolates. MDR Gram-negative bacteria accounted for 51.9% of wound infection isolates (95% CI: 45.95 to 58.33) while 6.3% (95% CI: 4.39 to 8.86) were XDR (nonsusceptibility to at least one agent in all but two or fewer antimicrobial categories). A high prevalence of bacterial isolates, with S. aureus as the predominant pathogen, showed high rates of multidrug resistance. This highlights the importance of monitoring antibiotic choices for prophylaxis and treatment in the study area.

Genetic Characterization of Methicillin-Resistant Staphylococcus aureus Isolated From Diabetic Foot Ulcers in a Tertiary Care Hospital in Mysuru, South India.

Background Diabetic foot ulcers (DFUs) are common complications in diabetes patients, often leading to sepsis and leg amputation. Methicillin-resistant Staphylococcus aureus (MRSA) infections in DFUs pose challenges due to methicillin resistance with mecA and mecC genes. This study aims to assess the prevalence of MRSA in clinical isolates from DFUs,analyze the antibiogram of MRSA isolates, and detect the presence of the mecA and mecC genes among MRSA isolates. Methodology The isolated S. aureus colonies were identified and antimicrobial susceptibility was performed using the Vitek-2 Compact system. Methicillin resistance was also confirmed through the disc diffusion method. Confirmed methicillin-resistant isolates were subjected to real-time polymerase chain reaction (RT-PCR) to detect mecA and mecC genes. Results A total of 474 purulent samples from DFUs yielded 541 distinct isolates, comprising 201 gram-positive and 340 gram-negative organisms. Among the gram-positive organisms, Staphylococcus species predominated, with 79 S. aureus isolates, 34 of which were methicillin-resistant. All MRSA isolates (100%) were sensitive to tetracycline, linezolid, teicoplanin, and vancomycin, and 94% were sensitive to cotrimoxazole but least susceptible to ciprofloxacin and levofloxacin. RT-PCR confirmed the presence of mecA genes in all 34 isolates and mecC genes in three isolates. Conclusions The presence of mecA in all 34 MRSA isolates underscores consistent methicillin resistance. The co-occurrence of mecA and mecC in three isolates hints at genetic diversity. Two MRSA isolates positive for mecC were isolated from rural patients involved in farming and animal husbandry, suggesting an occupational risk. The third patient was from a non-rural area, indicating potential alternative transmission pathways warranting further investigation.

Isolation and Diagnosis of Acinetobacter baumannii Isolates from Patients with Meningitis in Child Protection Hospital in Baghdad

Environmental contamination has been estimated to account for up to 20% of all hospital-acquired illnesses. Acinetobacter baumannii has recently become the predominant pathogen, posing a significant risk to human health. In present study, two hundred fifteen CSF samples were collected from children between the ages of new born to 14 years who were visiting child protection hospital in Baghdad. For the period from first of Oct 2023 to the end of Jan 2024, and the samples were sent for diagnosis. Isolates were identified after culturing them on MacConkey agar, blood agar, and mannitol salt agar. A number of biochemical tests were performed to detect Acinetobacter baumannii bacteria. The results indicated a negative oxidase reaction, a positive catalase reaction, a negative indole reaction, a negative methyl red reaction, a negative Voges-Proskauer reaction, and a positive citrate reaction, which were performed for the samples and for final diagnosis the Vitek-2 Compact system was used. After cultivation and diagnosis, 7 isolates of Acinetobacter baumannii were obtained out of 40 samples that showed positive culture results with bacterial growth.

Investigation of Flagellum genes FleN and FlgE and Gene Expression of FleN Gene in Pseudomonas Aeruginosa Clinical Isolates

The opportunistic multidrug resistance pathogen Pseudomonas aeruginosa has one or several flagella, and the numbers of these sophisticated machines are regulated by the flagellar regulator gene FleN. The flagellar hook gene FlgE is important for its synthesis, motility and tolerance to antibiotics. Bacteriahave resistance to antibiotics, especially to cephalosporin beta-lactam antibiotics. For the current study, 102 clinical specimens were collected and identified using routine laboratory tests and confirmed by Vitek-2 compact system. A total of 33 isolates of P. aeruginosa were identified. The antibiotic susceptibility test was done by the Vitek 2 Compact system. Flagellar gene detected by conventional PCR revealed that the FleN gene existed in 26 (78.8%), of which fifteen isolates were MDR. Whereas the FlgE gene existed in 20 (60.6%), of which fourteen isolates were MDR bacteria. The FleN gene expression in five isolates done by RT-qPCR revealed that four isolates were down regulated, and one isolate was up regulated in FleN gene expression when treated with ceftazidime at sub-MIC. While all isolates were downregulated when treated with amikacin at sub-MIC.

Phenotypic and molecular characterization of multidrug-resistant Enterobacterales isolated from clinical samples in Palestine: a focus on extended-spectrum β-lactamase- and carbapenemase-producing isolates

BackgroundInfections resulting from multidrug-resistant Enterobacterales (MDR-E) pose a growing global threat, presenting challenges in treatment and contributing significantly to morbidity and mortality rates. The main objective of this study was to characterize phenotypically and genetically extended-spectrum β-lactamase- and carbapenemase- producing Enterobacterales (ESBLE and CPE respectively) isolated from clinical samples in the West Bank, Palestine.MethodsA cross sectional study was conducted in October 2023 on clinical bacterial isolates collected from five governmental hospitals in the West Bank, Palestine. The isolates obtained from the microbiology laboratories of the participating hospitals, underwent identification and antibiotic susceptibility testing (AST) using the VITEK® 2 Compact system. ESBL production was determined by the Vitek2 Compact system. A modified carbapenem inactivation method (mCIM) was employed to identify carbapenemase-producing Enterobacterales (CPE). Resistance genes were detected by real-time PCR.ResultsOut of the total 1380 collected isolates, we randomly selected 600 isolates for analysis. Our analysis indicated that 287 (47.83%) were extended-spectrum beta-lactamase producers (ESBLE), and 102 (17%) as carbapenem-resistant Enterobacterales (CRE) isolates. A total of 424 isolates (70.67%) were identified as multidrug-resistant Enterobacterales (MDRE). The most prevalent ESBL species were K. pneumoniae (n = 124; 43.2%), E. coli (n = 119; 41.5%) and E. cloacae (n = 31; 10.8%). Among the CRE isolates, 85 (83.33%) were carbapenemase-producing Enterobacterales (CPE). The most frequent CRE species were K. pneumoniae (n = 63; 61.7%), E. coli (n = 25; 24.5%) and E. cloacae (n = 13; 12.8%). Additionally, 47 (7.83%) isolates exhibited resistance to colistin (CT), with 38 (37.62%) being CT-resistant CRE and 9 (3.14%) being CT-resistant ESBLE while sensitive to carbapenems. We noticed that 11 isolates (6 Klebsiella pneumoniae and 5 Enterobacter cloacae complex) demonstrated sensitivity to carbapenems by phenotype but carried silent CPE genes (1 blaOXA48, and 6 blaNDM, 4 blaOXA48, blaNDM). ESBL-producing Enterobacterales strains exhibited varied resistance patterns across different antibiotic classes. E. coli isolates showed notable 48% resistance to trimethoprim/sulfamethoxazole. K. pneumoniae isolates displayed a significant resistance to trimethoprim/sulfamethoxazole, nitrofurantoin, and fosfomycin (54%, 90%, and 70% respectively). E. cloacae isolates showed complete resistance to nitrofurantoin and fosfomycin. P. mirabilis isolates exhibited high resistance against fluoroquinolones (83%), and complete resistance to trimethoprim/sulfamethoxazole, nitrofurantoin and fosfomycin.ConclusionThis study showed the high burden of the ESBLE and CRE among the samples collected from the participating hospitals. The most common species were K. pneumoniae and E. coli. There was a high prevalence of blaCTXm. Adopting both conventional and molecular techniques is essential for better surveillance of the emergence and spread of antimicrobial-resistant Enterobacterales infections in Palestine.

Study the effect of some physical factors on three isolations of Candida albicans isolated from Iraqi patients

Background: The Candida spp. is considered an opportunistic fungi, as the infection increases when the immune system is weakened due to the exposure of the host to diseases or as a result of diabetes, immunodeficiency, cancerous diseases, or organ transplantation. Methods: The phenotypic and microscopic diagnosis methods for three isolates of Candida albicans isolated from different hospitals in Iraq were conducted along with the Vitek2 Compact System, then the diagnosis of isolated yeasts was confirmed based on PCR technology. The physical factors study was conducted to show the effect of temperature, pH concentration, and CO2 ratio on the three isolates of Candida albicans. Results: The three isolates contained one single bundle of extracted DNA. The PCR products using the fungal primer pair (ITS1, ITS4) showed the production of a single band for the three isolates of Candida albicans of 535bp. While the effect of high temperature on isolates, the best rate of growth was at 37°C, whereas isolate K8 recorded the highest growth rate then isolate B17 and T5, and no growth was recorded for the three isolates at 45°C. As for the effect of pH, the results showed that the best growth was at pH 6.2, where the highest growth rate was in isolate K8, followed by isolate T5 and then isolate B17. The results showed that a high percentage of CO2 harmed the growth rate, the best growth rate for all isolates was at a concentration of 0.03% of carbon dioxide. The highest growth rate was recorded in isolates K8, followed by B17 and then T5, while the lowest growth rate of isolates was at a concentration of 15% of carbon dioxide, as isolates recorded K8, followed by B17, then T5. Conclusions: In this study we found that Candida albicans has a gene expression of 535bp and there were effects of some physical factors characteristics on three isolates of pathogenic Candida albicans.

Bridging Diagnostic Gaps: Utilising HiCrome Agar and Tetrazolium Reduction Medium for the Rapid and Presumptive Identification and Speciation of Candida Species in Vulvovaginal Candidiasis in Low-Resource Environments.

Background Vulvovaginal candidiasis (VVC) is a common fungal infection caused by an overgrowth of Candida species, primarily Candida albicans (C. albicans). Using HiCrome agar and tetrazolium reduction medium offers cost-effectiveness in Candida detection by eliminating the need for additional tests, reducing equipment costs compared to automated systems, and simplifying workflow with direct species identification while maintaining high specificity. They expedite detection by directly identifying Candida species based on colony colour, bypassing the multiple steps of phenotypic methods. This efficiency saves time in the laboratory, providing rapid results without the extended processing times associated with automated systems and facilitating prompt diagnosis and treatment decisions. These diagnostic tools are especially valuable in low-resource environments where a quick and accurate diagnosis of VVC is crucial for effective treatment and management of antifungal resistance. Aims and objectives This study aims to evaluate the efficacy of HiCrome agar and tetrazolium reduction medium's efficacy in speciating Candida species in VVC cases. Materials and methods A cross-sectional observational study was conducted at Saveetha Medical College and Hospitals, Chennai, India, over six months. High vaginal swabs from 126 patients suspected of VVC were collected and plated on Sabouraud dextrose agar (SDA), HiCrome Candida differential agar (Himedia, Mumbai, India), and tetrazolium reduction medium. The results were compared with those obtained from the VITEK2 compact system (bioMérieux, Marcy-l'Étoile, France). Results Of the 126 samples, 74.6% showed single yeast infections, 7.9% displayed mixed yeast infections, and 17.5% showed no growth. A total of 114 Candida isolates were identified. Both HiCrome agar and tetrazolium reduction medium accurately identified all isolates, with complete concordance with the VITEK2 compact system. The most commonly isolated species were C. albicans (55.2%), Candida tropicalis (32.4%), Candida glabrata (8.8%), and Candida parapsilosis (3.6%). Both media provided rapid and accurate presumptive identification in low-resource settings. Conclusions HiCrome agar and tetrazolium reduction medium demonstrated high sensitivity and specificity in identifying Candida species. These methods are reliable for rapid and accurate diagnosis, particularly in resource-limited settings. However, they may require supplementary tests for definitive species identification. The adoption of these diagnostic tools represents a significant advancement in clinical microbiology, improving VVC management and addressing antifungal resistance.

Rapid detection of carbapenemase-producing gram-negative bacteria directly from blood culture bottles for a reliable guided empiric therapy.

Bloodstream infections (BSIs) caused by multidrug-resistant bacteria are a critical life-threatening challenge which necessitates the urgency to trigger life-saving treatment in a timely manner. This study aimed to evaluate the time required for rapid detection of carbapenemase-producing Enterobacterales (CPE) directly from blood culture bottles to optimize empirical treatment of BSI, especially in pediatric and infant patients, using a cost-effective method. This study included 419 Gram-negative bacteria, of which Klebsiella pneumoniae and Escherichia coli were the most common CPE causing BSI in pediatric and neonatal patients. Phenotypic and genotypic resistance of the selected isolates (45 K. pneumoniae and 9 E. coli) were determined by VITEK-2 Compact system and PCR, respectively. BACT/ALERT bottles were spiked with isolates. Finally, colorimetric RESIST-BC assay and Vitek-2 compact system were evaluated for the rapid detection of carbapenem-resistant bacteria directly from positive blood culture bottles. All selected isolates were phenotypically resistant to carbapenems. PCR showed that blaNDM and blaOXA-48 were present in all isolates, blaVIM was present in 44.4%, while blaKPC and blaIMP were entirely absent. The RESIST-BC kit showed good agreement with PCR for blaNDM and blaOXA-48, demonstrating high sensitivity and specificity, but not with blaVIM. These findings point out that RESIST-BC assay demonstrated an exceptionally short detection time for CPE, completing all cases within the first hour after the blood culture bottles flagged positive. It is also superior in providing a cluefor clinicians on antibiotic combinations that can be administered, depending on the type of β-lactamases detected, promptly and efficiently, with low expenses.

Aminoglycoside Susceptibility among Extensive Drug Resistant Pseudomonas aeruginosa from Hospitalized Patients in Al-Diwaniyah, Iraq

Abstract Background: Pseudomonas aeruginosa is one of the most prevalent Gram-negative microbes associated with serious and fatal nosocomial infections. It is routine to use aminoglycosides as a treatment for P. aeruginosa infections. Objectives: The dissemination of aminoglycoside resistance offers a major challenge to the treatment of life-threatening infections caused by these bacteria. Aim of Study: Determination of aminoglycoside-modifying enzymes and 16S ribosomal RNA methylases in extensive-drug resistant (XDR) P. aeruginosa isolates. Materials and Methods: From November 2021 to August 2022, a total of 200 samples were collected in this cross-sectional study including burns (n = 80, 40%), wounds (n = 66, 33%), and diabetic foot ulcers (n = 54, 27%) from admitted patients to Al-Diwaniyah Burn Center and Al-Diwaniyah Teaching Hospital. The identification and antibiotic susceptibility profile of P. aeruginosa were done by vitek2 compact system. The isolates were subjected to polymerase chain reaction assays with specific primers for ant(4’)-IIa, ant(4’)-IIb, acc(6’)-Ia, aph(3’)-IIb, rmtA, and rmtD. Results: The recovery rate of P. aeruginosa isolates was (n = 50, 25.0%) from the clinical samples. Antibiotic-susceptibility patterns demonstrated that 18% of the isolates were multi-drug resistant and 22 (44%) were XDR. The XDR isolates were resistant to all 14 antibiotics related to the seven antibiotic classes tested in this study. The prevalence of aminoglycoside resistance genes among XDR isolates is ant(4’)-IIa (22.7%), (4’)-IIb (27.3%), acc(6’)-Ia (18.18%), aph(3’)-IIb (100%), rmtA (36.36%), rmtD (36.36%), mexZ and parR (100%). Conclusion: Increased resistance to aminoglycosides in Al-Diwaniyah Hospitals serves to highlight how critical this issue is when treating multidrug-resistant P. aeruginosa infections that are life-threatening. All the resistance isolates harbored aph(3’)-IIb gene.

Genetic Basis of Biofilm Formation Genes Ebp and Bph (phos) among Multidrug Resistance Enterococcus faecalis Isolates, Iraq

Abstract Background: Biofilm produced by Enterococcus spp. increase their inherent and acquired antibiotic resistance, posing a significant challenge to infection treatment, particularly in virulent strains. Objective: This study aimed to investigate some genes responsible for biofilm formation (Bph (phos) and EbpB) by polymerase chain reaction (PCR) technique. Materials and Methods: A total of 130 clinical samples were collected during this study, which were obtained from patients who were admitted to Feminine and Children Teaching Hospital in Al-Diwaniyah City during a period extending from (November 2022 to March 2023). All samples were subjected to culturing on different media (blood agar, MacConkey, Bile Esculin agar, and M-El chromogenic ager), after which catalase and oxidase tests were conducted biochemically. After cultivation, the VITEK-2 compact system was used to identify the samples. The isolates were investigated genotypically for harboring biofilm formation genes, including EbpB and Bph (phos), by molecular method (PCR). Results: The VITEK-2 compact system revealed that only 12 isolates were identified as E. faecalis. The most effective antibiotics against E. faecalis were (vancomycin, teicoplanin, linezolide, tigecycline, and ampicillin), and the highest resistance was against erythromycin (100%) and tetracycline (91.6%). Enterococcus faecalis isolates were investigated genotypically for harboring biofilm formation genes that include EbpB and Bph (phos) by molecular methods, PCR. The results showed that EbpB and Bph (phos) genes were positive for all isolates with a percentage of 100%. Conclusions: It was found that the presence of biofilm formation genes in E. faecalis EbpB, and phos (Bph) increase the pathogenicity of this pathogen. These genes showed a high percentage among E. faecalis isolates. Also, all isolates had the potential to form a biofilm, which complicates their treatment with antibiotics, confirming the critical need to develop novel antimicrobial agents that control the infection associated with the development.

Genomic and Phenotypic Analysis of bla KPC-2 Associated Carbapenem Resistance in Klebsiella aerogenes: Insights into Clonal Spread and Resistance Mechanisms Across Hospital Departments in Beijing.

This study conducted an phenotypic and whole-genome sequencing analysis with Klebsiella aerogenes to elucidate its clinical epidemiological characteristics, antimicrobial resistance (AMR) phenotype, biofilm formation ability and hemolytic activity testing, AMR genes and phylogenetic relationships, so as to provide a further understanding of the intra-hospital strain transmission. Samples were collected from a hospital in Beijing between 2020 and 2022. All strains underwent bacterial identification, antimicrobial susceptibility testing (AST) using the VITEK-2 compact system. Biofilm formation ability and hemolytic activity were tested. Second-generation sequencing was applied to all strains, with those carrying the bla KPC gene were selected for third-generation sequencing. Whole-genome analysis identified resistance genes, plasmid types, MLST typing, and phylogenetic relationships. Plasmids were assembled to detect plasmid structures and AMR gene location. Among the 42 K. aerogenes isolates, 21 were carbapenem-resistant K. aerogenes (CRKA). All strains exhibited strong biofilm formation and no hemolytic activity. Most were sourced from sputum (83.3%). CRKA demonstrated extensive resistance to antibiotics, particularly β-lactamase inhibitors and Cefotetan. This resistance pattern was closely associated with the presence of an IncFII(pHN7A8) plasmid, which carried multiple resistance genes, including bla KPC-2, bla CTX-M-65, bla TEM-1, rmtB and a large number of mobile elements. The majority of CRKA strains clustered within the same branch of the phylogenetic tree, exhibiting minimal single nucleotide polymorphism (0-13 SNPs) differences, and they shared the same sequence type (ST292), resistance genes, and plasmids, originating from different departments, suggesting clonal transmission among the hospital. Our research reveals that the clonal transmission of CRKA occurs across various departments within the hospital. The widespread resistance observed in CRKA, attributed to the presence of bla KPC and ESBLs genes, underscores the need for heightened vigilance to prevent the further dissemination of CRKA within the hospital and, potentially, throughout the wider community.

Association of Nosocomial Burns and Bacterial Colonization in Iraqi Patients

Burn injury is a prevalent and severe form of trauma, posing a significant global public health concern. This study included isolating causative agents involved in nosocomial burns in Iraqi patients. 65 swabs from burn wounds were collected aseptically from a specialty hospital in Baghdad city. The swabs were cultured on routinely used culture media prepared in the laboratory and diagnosed using conventional biochemical tests, and the VITEK-2 compact system validated their findings. The findings revealed that 47 (72.3%) isolates had growth, and the remaining 27.7% of the swabs did not grow. Pseudomonas aeruginosa was the predominant species bacteria isolated in percent (43%), followed by Staphylococcus aureus in percent (26%), Corynebacterium spp. (11%), Proteus vulgaris (6%), whereas "Escherichia coli, Enterococcus faecalis, and Serratia marcescens" isolated in similar percent (4%), and Klebsiella spp. in the lowest percent (2%). Moreover, antibiotic susceptibility testing was also done using VITEK-2 compact system against Amoxiclav, Ticarcillin, Ceftriaxone, Imipenem, Gentamicin, Amikacin, Tetracycline, Doxycycline, Ciprofloxacin, and Erythromycin.

Antibiotic Resistance Patterns in Bacterial Conjunctivitis

Background: The conjunctivitis, known generally as pink eyes, is the inflammation of the inner eyelids, as well as the entire surface of the eye´s outermost part, which makes it get a reddish-pink look. The symptoms may involve pain, burning and itching, most often when an allergic cause is implicated. Method: The present work considered 306 scenarios of human blepharitis, cultured swabs were plated on MacConkey agar and Blood agar used streak technique and incubated at 37°C in a 24-hour experiment. Bacterial isolates were pointed based on their appearance, gram-staining, direct microscopy and biochemical tests comprising of catalase, oxidase, mannitol fermentation and hemolysis. Enterosystem 18 R system and the Vitek-2 compact system were used for the confirmation of bacterial species. Microplate method was used to test for biofilm formation of the bacterial isolates. Results: Antibiotic resistance test of isolates, however, reflected relatively high resistance among them, with Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pneumoniae, Moraxella catarrhalis and Klebsiellapneumoniae all being 100% resistant to amoxicillin. Klebsiella pneumonia and E. coli isolates showed a 90% resistance to moxifloxacin, and to ciprofloxacin by Staphylococcus aureus isolates. Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus vulgaris, and Streptococcus pneumoniae exhibited significant biofilm production, whereas the other isolated species showed lower biofilm-forming tendencies.

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.

In vitro antimicrobial activity of silver nanoparticles against selected Gram-negative and Gram-positive pathogens.

Infections caused by pathogenic bacteria increase patient morbidity and mortality and significantly raise treatment costs. The use of silver nanoparticles as an alternative treatment for S aureus, E coli, MRSA, E faecalis, K pneumoniae and P aeruginosa indicates their antibacterial effect and prompts medical research to consider the next generation of antibacterial drugs that could change antibiotic therapy. By combining silver nanoparticles with different classes of antibiotics, the antibacterial effect is evidenced by increased values of the inhibition zone compared to the values obtained for some antibiotics commonly used in the treatment of bacterial infections. This study focuses on comparing the antibacterial activity of antibiotics versus antibiotics combined with silver nanoparticles against various bacteria, by comparing inhibition zones obtained for both. We aim to prove that the size of the inhibition zone for antibiotics combined with silver nanoparticles is greater, thus confirming the improved antibacterial effect. In this study we tested the antibacterial activity of solutions of silver nanoparticles alone or in combination with different antibiotics. We used standard bacterial strains, ATCC, both Gram positive bacteria Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, as well as Gram negative bacteria Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, but also on clinical isolates: a strain MRSA (Methicillin Resistant Staphylococcus aureus) and a PDR strain (pan drug resistant) of Klebsiella pneumoniae. Bacterial identification was performed using Vitek MS analyzer (bioMerieux). Antibiotic susceptibility determination was performed with VITEK2 COMPACT SYSTEM (bio Merieux, Inc Durham NC) with ready to use VITEK AST cards. The interpretation of the results was done in compliance with EUCAST 2023-2024 standards. Testing was performed for several classes of antibiotics, silver nanoparticle solutions in 2 concentrations (10 μg/mL and 100 μg/mL) and for combinations of antibiotics with silver nanoparticle solutions. The diameter of the inhibition zone (ZOI) for silver nanoparticles, antibiotics and silver nanoparticles combined with antibiotic against each bacterium was expressed in millimeters. The Kirby-Bauer disk-diffusion method, in accordance with current EUCAST standards, was used to analyze the antibacterial effect of antibiotics, silver nanoparticles, and antibiotics combined with silver nanoparticles at biocompatible doses of 10 and 100 μg/mL. The experiments were conducted in triplicate, and the results were almost identical. The results of this study show that the silver nanoparticles displayed antibacterial activity, proven by the appearance of the inhibition zone, in various sizes, for all bacteria studied. The antibiotic classes tested were beta-lactamins, first, second, third and fourth generation cephalosporins, macrolides, fluoroquinolones, lincosamides, aminoglycosides, glycopeptides, tetracyclines, oxazolidinones, sulfonamides, rifamycins, amphenicols. Testing S aureus ATCC 29213, the highest zone of inhibition was demonstrated for cephalosporins (32.6667 ± 0.701 mm), macrolides (31.6667 ± 0.701 mm, and lincosamides (29.6667 ± 0.701 mm). Testing MRSA (internal code GR0333), the highest zone of inhibition for combination of silver nanoparticles and antibiotics was demonstrated for fluoroquinolones (36.3333 ± 0.701 mm), lincosamides (32.3333 ± 0.701 mm), Fusid acid (32.3333 ± 0.701 mm) and aminoglicosides (31.3333 ± 0.701 mm). Testing E coli ATCC 25922 the highest zone of inhibition was for Fosfomycine, 39 mm and for E faecalis ATCC 29212 for aminoglicosides was 19 mm. For K pneumoniae (internal code GQ8575) the inhibition zone for silver nanoparticles 100 μg/mL was 12.3333 ± 0.701 mm and for P aeruginosa ATCC 27253 was 16 ± 1.214 mm. The use of metallic nanoparticles, especially silver ones, as antimicrobial agents with definite bactericidal activity has led medical specialists to consider this new treatment which may change antibacterial therapy. Studies of in vitro combinations between silver nanoparticles and different classes of antibiotics represent a highly efficient and effective new antibacterial treatment against multidrug-resistant bacteria. To avoid the problem of antimicrobial resistance associated with conventional antibiotics, it is necessary to understand the adaptive mechanisms of bacteria under the action of metal nanoparticles, which could be exploited in future studies. Further in vitro and in vivo studies that would assess specify the biocompatibility and toxicity of silver nanoparticles will make these super nanomaterials the medicines of the future.

Antibacterial Activitiy of Triterpeniod Compounds

The goal of the study was to ascertain whether particular pathogenic bacteria could be inhibited by triterpeniod substances obtained from Rosmarinus officinalis (rosemary) extracts. The time frame for completing this construction was July 2023–April 2024. At the beginning, 100 specimens were taken from patients who were undergoing treatment at the Burn Cure Center in Nineveh Governorate, Iraq Routine biochemical testing were used to determine burn infections caused by bacteria, and the Vitek2 compact system was used to confirm the diagnosis. Acinetobacter baumani and Pseudomonas auroginosa were the most common isolates. In order to extract the substance, rosemary (R. officinalis) leaves were air-dried in the shade and then processed into a fine powder using a grinding machine. A soxhlet device was used to extract 50 g of powdered leaves for six hours at 40–60 °C using 250 ml of 75% petroleum ether. Afterwards, the mixture was dried out at 40°C in a rotating evaporator. After being weighed, the extract residue was stored until needed. Using gas chromatography/mass spectrometry (GC/MS), the crude extract was examined. Ursolic acid (1.38), oleanolic acid (3.27), and other triterpeniod substances with varying ratios were identified by GC-MS analysis. The antibacterial activity of triterpeniod compounds was assessed at concentrations of 12.5%, 25%, 50%, and 100% using the well-diffusion Kirby-Bauer method. The test was evaluated in comparison to six bacterial strains. The results indicated that staphylococcus aureus (50%:22mm – 100%: 26mm), staphylococcus haemolyticus (100%: 17mm), and Acinetobacter baumani (50%:18mm – 100%: 22mm) had the highest inhibitory.

Investigating the bacterial consortia properties of electrogenic anodic biofilm in a double-chamber microbial fuel cell: electrochemical, physical, biochemical and molecular characterization

This work evaluated the electrochemical, physical, biochemical, and molecular characterization of electrogens from a graphite felt anode when zinc oxide on activated carbon (ZnO/AC) was used as a cathodic electrocatalyst in a double-chambered microbial fuel cell (DCMFC). The electrochemical polarization behavior of the DCMFC showed that ZnO/AC had a higher power density (PDmax) of 89 mW m−2 with a corresponding cell current density (CD) of 248 mA m−2 and a voltage output of 395 mV, which was higher than those of the blank electrode used as a benchmark (PDmax of 68 mW m−2 at a CD of 161 mA m−2 and a voltage of 421 mV). Furthermore, scanning electron microscopy and transmission electron microscopy revealed that the morphology and interior properties of the strains varied among the rods (bacilli), spirals (vibrios), and spheres (diplococci, staphylococci and streptococci). In addition, biochemical characterization via the Vitek2 compact system and molecular analysis via 16 S rRNA and 18 S rRNA gene sequencing revealed the occurrence of nine prevalent species that were correlated with Sphingobacterium spiritivorum, Ochrobactrum anthropicus, Pseudomonas mendocina, Stenotrophomonas maltophilia, Leuconostoc mesenteroides, Staphylococcus equorum, Bacillus subtilis HQ334981.1, Kocuria kristinae KC581674.1 and Saccharomyces cerevisiae NR111007.1. Consequently, the present study outlines different characterization strategies for electrogenic microbes that play an important role in the overall performance of DCMFC for scaling up and managing existing environmental pollution for sustainable energy generation.

Antimicrobial effect of biosynthesis of selenium nanoparticles by Pseudomonas aeruginosa on bacteria isolated from wounds and burns

Abstract: background: In recent decades, the rise of antibiotic resistance as critical global health challenges, necessitating innovative approaches to address these pressing issues. The Center of Disease Control (CDC) estimates that antibiotic resistance is responsible for nearly 5 million deaths in 2019 Objective: This study aims to biosynthesise selenium nanoparticles and the possibility of using as antimicrobal. Methods: Samples were collected from Al-Diwaniyah Teaching Hospital in Al-Diwaniyah Governorate - Iraq , period from April 1, 2023 to June 1, 2023. Bacterial samples were collected from wounds and burns, then they were diagnosed using (Vitek-2 compact system- Biomerieux-France), then all the collected bacterial species were tested to produce selenium nanoparticles and the best bacteria capable of producing them were selected. The synthesis process involved incubation, centrifugation, and purification. The antimicrobal activity of SeNPs was evaluated .Results : Pseudomonas aeruginosa was the predominant pathogen accounting for 30%, followed by Bacillus (24%), Staphylococcus (16%), Escherichia coli (8%), and Candida albicans (12%). Mixed infections are found in 10%. Statistical analysis showed (chi-square = 40.32, p < 0.0001). The bacilli showed high sensitivity to ciprofloxacin (Cip) with a mean diameter of 28 ± 1.02, while amoxicillin (AX), ceftoxime (CTX), doxycycline (DO), and carbenicillin (PY) had no inhibitory effect (0 ± 0). Staphylococci showed sensitivity to ciprofloxacin (18 ± 0.64), amoxicillin (13 ± 0.22), cefatoxime (12 ± 0.4), doxycycline (12 ± 0.4), nitrofuranthone (THAT) (11 ± 1), and neomycin (17.2 ± 1.1). Escherichia coli showed sensitivity to ciprofloxacin (28 ± 1.02) and doxycycline (19 ± 1.4), while Candida albicans showed resistance to all antibiotics tested. Antimicrobial activity was measured using concentrations of 125, 250, 500, and 1000 μg/mL. Results show a concentration-dependent increase in inhibitory effects. Antibiofilm activity ranges from 2 to 1048 μg/mL.Discussion: Lower concentrations (125 µg/ml), minimal inhibition was observed, but as the concentration increased, a clear trend of enhanced inhibition emerged. Notably, at 250 µg/ml, significant growth inhibition was evident, with a concentration-dependent response. The highest concentration (1000 µg/ml) exhibited the most substantial inhibitory effects. The absence of inhibition in the negative control confirms the specificity of nano selenium's impact.conclusion. : The results demonstrate concentration-dependent inhibitory effects of nano selenium on various bacterial species.