CORNEAL - Word Related Documents




#
Rank
Similarity
Title + Abs.
Year
PMID
012345
600300.9754Contact Lens Wear Alters Transcriptional Responses to Pseudomonas aeruginosa in Both the Corneal Epithelium and the Bacteria. PURPOSE: Healthy corneas resist colonization by virtually all microbes yet contact lens wear can predispose the cornea to sight-threatening infection with Pseudomonas aeruginosa. Here, we explored how lens wear changes corneal epithelium transcriptional responses to P. aeruginosa and its impact on bacterial gene expression. METHODS: Male and female C57BL/6J mice were fitted with a contact lens on one eye for 24 h. After lens removal, corneas were immediately challenged for 4 h with P. aeruginosa. A separate group of naïve mice were similarly challenged with bacteria. Bacteria-challenged eyes were compared to uninoculated naive controls as was lens wear alone. Total RNA-sequencing determined corneal epithelium and bacterial gene expression. RESULTS: Prior lens wear profoundly altered the corneal response to P. aeruginosa, including: upregulated pattern-recognition receptors (tlr3, nod1), downregulated lectin pathway of complement activation (masp1), amplified upregulation of tcf7, gpr55, ifi205, wfdc2 (immune defense) and further suppression of efemp1 (corneal stromal integrity). Without lens wear, P. aeruginosa upregulated mitochondrial and ubiquinone metabolism genes. Lens wear alone upregulated axl, grn, tcf7, gpr55 (immune defense) and downregulated Ca2(+)-dependent genes necab1, snx31 and npr3. P. aeruginosa exposure to prior lens wearing vs. naïve corneas upregulated bacterial genes of virulence (popD), its regulation (rsmY, PA1226) and antimicrobial resistance (arnB, oprR). CONCLUSION: Prior lens wear impacts corneal epithelium gene expression altering its responses to P. aeruginosa and how P. aeruginosa responds to it favoring virulence, survival and adaptation. Impacted genes and associated networks provide avenues for research to better understand infection pathogenesis.202439677621
600410.9753Contact Lens Wear Alters Transcriptional Responses to Pseudomonas aeruginosa in Both the Corneal Epithelium and the Bacteria. PURPOSE: Healthy corneas resist colonization by virtually all microbes, yet contact lens wear can predispose the cornea to sight-threatening infection with Pseudomonas aeruginosa. Here, we explored how lens wear changes corneal epithelium transcriptional responses to P. aeruginosa and its impact on bacterial gene expression. METHODS: Male and female C57BL/6J mice were fitted with a contact lens on one eye for 24 hours. After lens removal, corneas were immediately challenged for 4 hours with P. aeruginosa. A separate group of naïve mice was similarly challenged with bacteria. Bacteria-challenged eyes were compared to uninoculated naïve controls, as was lens wear alone. Total RNA sequencing determined corneal epithelium and bacterial gene expression. RESULTS: Prior lens wear profoundly altered the corneal response to P. aeruginosa, including upregulated pattern recognition receptors (tlr3, nod1); downregulated lectin pathway of complement activation (masp1); amplified upregulation of tcf7, gpr55, ifi205, and wfdc2 (immune defense); and further suppression of efemp1 (corneal stromal integrity). Without lens wear, P. aeruginosa upregulated mitochondrial and ubiquinone metabolism genes. Lens wear alone upregulated axl, grn, tcf7, and gpr55 (immune defense) and downregulated Ca2+-dependent genes necab1, snx31, and npr3. P. aeruginosa exposure to prior lens wearing versus naïve corneas upregulated bacterial genes of virulence (popD), its regulation (rsmY, PA1226), and antimicrobial resistance (arnB, oprR). CONCLUSIONS: Prior lens wear impacts corneal epithelium gene expression, altering its responses to P. aeruginosa and how P. aeruginosa responds to it favoring virulence, survival, and adaptation. Impacted genes and associated networks provide avenues for research to better understand infection pathogenesis.202539932472
600720.9722Human tear fluid modulates the Pseudomonas aeruginosa transcriptome to alter antibiotic susceptibility. PURPOSE: Previously, we showed that tear fluid protects corneal epithelial cells against Pseudomonas aeruginosa without suppressing bacterial viability. Here, we studied how tear fluid affects bacterial gene expression. METHODS: RNA-sequencing was used to study the P. aeruginosa transcriptome after tear fluid exposure (5 h, 37 (o)C). Outcomes were further investigated by biochemical and physiological perturbations to tear fluid and tear-like fluid (TLF) and assessment of bacterial viability following tear/TLF pretreatment and antibiotic exposure. RESULTS: Tear fluid deregulated ~180 P. aeruginosa genes ≥8 fold versus PBS including downregulating lasI, rhlI, qscR (quorum sensing/virulence), oprH, phoP, phoQ (antimicrobial resistance) and arnBCADTEF (polymyxin B resistance). Upregulated genes included algF (biofilm formation) and hemO (iron acquisition). qPCR confirmed tear down-regulation of oprH, phoP and phoQ. Tear fluid pre-treatment increased P. aeruginosa resistance to meropenem ~5-fold (4 μg/ml), but enhanced polymyxin B susceptibility ~180-fold (1 μg/ml), the latter activity reduced by dilution in PBS. Media containing a subset of tear components (TLF) also sensitized bacteria to polymyxin B, but only ~22.5-fold, correlating with TLF/tear fluid Ca(2+) and Mg(2+) concentrations. Accordingly, phoQ mutants were not sensitized by TLF or tear fluid. Superior activity of tear fluid versus TLF against wild-type P. aeruginosa was heat resistant but proteinase K sensitive. CONCLUSION: P. aeruginosa responds to human tear fluid by upregulating genes associated with bacterial survival and adaptation. Meanwhile, tear fluid down-regulates multiple virulence-associated genes. Tears also utilize divalent cations and heat resistant/proteinase K sensitive component(s) to enhance P. aeruginosa sensitivity to polymyxin B.202134332149
140230.9656Detection of β-lactam resistance genes in Gram-negative bacteria from positive blood cultures using a microchip-based molecular assay. BACKGROUND: Accurate detection of β-lactam resistance genes in bloodstream infections is critical for guiding antimicrobial therapy. This study evaluates the Alifax Gram-negative resistance (GNR) microchip assay for detecting β-lactam resistance genes directly from positive blood cultures (PBCs) for Gram-negative (GN) bacteria, including Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii. METHODS: Simulated (n=146) and clinical (n=106) GN-PBC samples were tested for bla (KPC), bla (VIM), bla (NDM), bla (IMP), bla (OXA-23)-like, bla (OXA-48)-like, bla (SHV)-ESBL, bla (CTX-M-1/9) group, and bla (CMY-2)-like genes using the GNR microchip assay. Whole-genome sequencing (WGS) served as the reference assay for simulated samples and, selectively, for clinical samples. The bioMérieux BioFire Blood Culture Identification 2 (BCID2) panel assay was used as a comparator for clinical samples. RESULTS: The GNR microchip assay correctly identified 203 (99.5%) of 204 β-lactam resistance genes in simulated samples. One sample tested false negative for a bla (SHV)-ESBL gene but true positive for a bla (KPC) gene. In clinical samples, GNR results were concordant with BCID2 for 113 (100%) of 113 genes included in both assays. Additionally, the GNR assay detected bla (CMY-2) -like (n=6), bla (OXA-23)-like (n=5), and bla (SHV)-ESBL (n=2), which are not targeted by BCID2, all confirmed by WGS. In two β-lactam-resistant P. aeruginosa samples but negative by the GNR assay, WGS confirmed the absence of acquired β-lactam resistance genes, suggesting alternative resistance mechanisms. CONCLUSION: The GNR microchip assay demonstrated high concordance and broader β-lactam resistance gene coverage compared to BCID2, supporting its potential role in routine diagnostics. Further validation in larger, prospective studies is warranted.202540529307
147340.9654Evaluation of the Unyvero i60 ITI® multiplex PCR for infected chronic leg ulcers diagnosis. OBJECTIVES: Unyvero i60 ITI multiplex PCR (mPCR) may identify a large panel of bacteria and antibiotic resistance genes. In this study, we compared results obtained by mPCR to standard bacteriology in chronic leg ulcer (CLU) infections. METHODS: A prospective study, part of the interventional-blinded randomized study "ulcerinfecte" (NCT02889926), was conducted at Saint Joseph Hospital in Paris. Fifty patients with a suspicion of infected CLU were included between February 2017 and September 2018. Conventional bacteriology and mPCR were performed simultaneously on deep skin biopsies. RESULTS: Staphylococcus aureus and Pseudomonas aeruginosa were the most detected pathogens. Regarding the global sensitivity, mPCR is not overcome to the standard culture. Anaerobes and slow growing bacteria were detected with a higher sensitivity rate by mPCR than standard culture. CONCLUSION: Unyvero i60 ITI multiplex PCR detected rapidly pathogenic bacteria in infected CLU especially anaerobes and slow growing bacteria and was particularly effective for patients previously treated with antibiotics.202031790779
218850.9654Detection of Virulence Factors and Antibiotic Resistance Pattern of Clinical and Intensive Care Unit Environmental Isolates of Pseudomonas aeruginosa. BACKGROUND: Pseudomonas aeruginosa is a gram-negative non-glucose fermenting aerobic bacteria and an opportunistic pathogen in humans and animals. The present study was carried out to investigate the distribution of virulence factors and antibiotic resistance properties of P. aeruginosa isolated from patients and intensive care unit (ICU) environment. MATERIAL AND METHODS: A total of 116 P. aeruginosa isolated from patients and ICU environment were collected from Besat hospital in Hamadan, the West of Iran. P. aeruginosa isolates were analyzed based on the presence of the virulence factors encoding genes included exoA, exoS, exoU, and algD using polymerase chain reaction (PCR). Antimicrobial susceptibility test was performed using a disk diffusion method. RESULTS: The results showed the prevalence of exoA 33 (56.9%), exoS 21 (36.20%), exoU 37 (63.8%), and algD 35 (60.34%) genes in ICU environment P. aeruginosa strains and exo A 23 (39.25%), exoS 25 (43.1%), exoU 40(68.98%), and algD 25 (43.1%) genes in clinical isolates of P. aeruginosa. High resistance levels of the clinical and ICU environment isolate to ampicillinsulbactam (100%), were also observed. CONCLUSION: Our findings should raise awareness about antibiotic resistance in hospitalized patients in Iran. Clinicians should exercise caution in prescribing antibiotics, especially in cases of human infections.202031889501
140660.9653Multicentre study of the burden of multidrug-resistant bacteria in the aetiology of infected diabetic foot ulcers. BACKGROUND: Infected diabetic foot ulcer (IDFU) is a public health issue and the leading cause of non-traumatic limb amputation. Very few published data on IDFU exist in most West African countries. OBJECTIVE: The study investigated the aetiology and antibacterial drug resistance burden of IDFU in tertiary hospitals in Osun state, Nigeria, between July 2016 and April 2017. METHODS: Isolates were cultured from tissue biopsies or aspirates collected from patients with IDFU. Bacterial identification, antibiotic susceptibility testing and phenotypic detection of extended-spectrum beta-lactamase and carbapenemase production were done by established protocols. Specific resistance genes were detected by polymerase chain reaction. RESULTS: There were 218 microorganisms isolated from 93 IDFUs, comprising 129 (59.2%) Gram-negative bacilli (GNB), 59 (27.1%) Gram-positive cocci and 29 (13.3%) anaerobic bacteria. The top five facultative anaerobic bacteria isolated were: Staphylococcus aureus (34; 15.6%), Escherichia coli (23; 10.6%), Pseudomonas aeruginosa (20; 9.2%), Klebsiella pneumoniae (19; 8.7%) and Citrobacter spp. (19; 8.7%). The most common anaerobes were Bacteroides spp. (7; 3.2%) and Peptostreptococcus anaerobius (6; 2.8%). Seventy-four IDFUs (80%) were infected by multidrug-resistant bacteria, predominantly methicillin-resistant S. aureus and GNB producing extended-spectrum β-lactamases, mainly of the CTX-M variety. Only 4 (3.1%) GNB produced carbapenemases encoded predominantly by bla (VIM). Factors associated with presence of multidrug-resistant bacteria were peripheral neuropathy (adjusted odds ratio [AOR] = 4.05, p = 0.04) and duration of foot infection of more than 1 month (AOR = 7.63, p = 0.02). CONCLUSION: Multidrug-resistant facultative anaerobic bacteria are overrepresented as agents of IDFU. A relatively low proportion of the aetiological agents were anaerobic bacteria.202133824857
247970.9653Down-regulatory effects of green coffee extract on las I and las R virulence-associated genes in Pseudomonas aeruginosa. BACKGROUND: Antibiotic resistant strains of Pseudomonas aeruginosa are the cause of Gram negative nosocomial infections especially among the immunosuppressed patients. The bacteria contains las I and las R genes that play very important roles in the pathogenesis and mechanisms of aggression. These genes can be influenced by the quorum sensing (QS) system and such mechanism is becoming clinically important worldwide. This study aimed to investigate the preventive effects of green coffee extract (GCE) on the expression of pathogenesis-related genes, las I and las R in P. aeruginosa. METHODS: A total of fifty four P. aeruginosa strains were isolated out of 100 clinical samples collected from the infectious wards in different hospitals (Tehran province) using conventional microscopic and biochemical methods. Susceptibility of the isolates to different antibiotics, GCE and chlorogenic acid were elucidated. Multiplex polymerase chain reaction (PCR) and real-time PCR were performed to detect and quantify the expression levels of las I and las R genes. The presence of chlorogenic acid in GCE was confirmed by HPLC. RESULTS: Antibiotic susceptibility tests revealed multidrug resistance among the clinical isolates of those 40 strains were resistant to ciprofloxacin (74.07%), 43 to ceftazidime (79.26%), 29 to amikacin (53.7%), 42 to ampicillin (77.77%), 17 to colistin (31.48%), 40 to gentamicin (74.77%), and 50 to piperacillin (92.59%). PCR outcomes exhibited that the frequency of las I and las R genes were 100% in resistant and sensitive strains isolated from clinical and standard strains of P. aeruginosa (ATCC 15449). Real-time PCR analyses revealed that GCE significantly prevented the expression of las I and las R genes in P. aeruginosa. GCE at concentration level as low as 2.5 mg/mL could prevent the expression of lasI and lasR genes in P. aeruginosa clinical isolates. CONCLUSION: The presence and expression levels of las I and las R genes in P. aeruginosa isolates were investigated when the bacteria was exposed to GCE. Our results tend to suggest that genes involved in pathogenesis of:Pseudomonas aeruginosa are down regulated by quorum sensing effect of chlorogenic acid and therefore GCE could be useful as an adjuvant in combating multidrug resistance strains of Pseudomonas aeruginosa.201931187452
142580.9652Distribution and Antimicrobial Resistance of Complicated Intraabdominal Infection Pathogens in Two Tertiary Hospitals in Egypt. Background: Management of complicated intraabdominal infections (cIAIs) requires containment of the source and appropriate initial antimicrobial therapy. Identifying the local data is important to guide the empirical selection of antimicrobial therapy. In this study, we aimed to describe the pathogen distribution and antimicrobial resistance of cIAI. Methods: In two major tertiary care hospitals in Egypt, we enrolled patients who met the case definition of cIAI from October 2022 to September 2023. Blood cultures were performed using the BACTAlert system (BioMerieux, Marcy l'Etoile, France). A culture of aspirated fluid, resected material, or debridement of the infection site was performed. Identification of pathogens and antimicrobial susceptibility testing were conducted by the VITEK-2 system (BioMerieux, Marcy l'Etoile, France). Gram-negative resistance genes were identified by PCR and confirmed by whole bacterial genome sequencing using the Nextera XT DNA Library Preparation Kit and sequencing with the MiSeq Reagent Kit 600 v3 (Illumina, USA) on the Illumina MiSeq. Results: We enrolled 423 patients, 275 (65.01%) males. The median age was 61.35 (range 25-72 years). We studied 452 recovered bacterial isolates. Gram-negative bacteria were the vast majority, dominated by E. coli, followed by Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Proteus mirabilis (33.6%, 30.5%, 13.7%, 13%, and 5.4%, respectively). High rates of resistance were detected to third- and fourth-generation cephalosporins and fluoroquinolones. No resistance was detected to colistin. Resistance to amikacin and tigecycline was low among all isolates. Resistance to meropenem and ceftazidime/avibactam was moderate. ESBL genes were common in E. coli and K. pneumoniae. CTX-M15 gene was the most frequent. Among Enterobacterales, bla(OXA-48) and bla(NDM) were the most prevalent carbapenemase genes. Pseudomonas aeruginosa isolates harbored a wide variety of carbapenemase genes (OXA, NDM, VIM, SIM, GIM, SPM, IMP, AIM), dominated by metallo-beta-lactamases. In 20.6% of isolates, we identified two or more resistance genes. Conclusion: High resistance rates were detected to third- and fourth-generation cephalosporins and fluoroquinolones. Amikacin and tigecyclines were the most active antimicrobials. Our data call for urgent implementation of antimicrobial stewardship programs and reinforcement of infection control.202439172656
97590.9652Clonal diversity, antimicrobial resistance, and genome features among nonfermenting gram-negative bacteria isolated from patients with cystic fibrosis in Russia. Nonfermenting gram-negative (NFGN) bacteria were isolated from cystic fibrosis (CF) patients and subjected to susceptibility testing and whole-genome sequencing. Among 170 enrolled CF patients, 112 (65.9%) were colonized with at least 1 key NFGN species. The species-specific infection rate was highest for Pseudomonas aeruginosa (40.6%) followed by Stenotrophomonas maltophilia (14.1%), Achromobacter spp. (9.4%), and Burkholderia cepacia complex (Bcc, 8.2%) demonstrating a significant age-dependent increase for P. aeruginosa and Achromobacter spp., but not for S. maltophilia or Bcc. P. aeruginosa sequence types (STs) related to high-risk epidemic and global CF clones were carried by 12 (7.1%) and 13 (7.6%) patients, respectively. In total, 47% NFGN isolates, predominantly P. aeruginosa, harbored at least 1 plasmid-borne resistance gene; 5 ST235 isolates carried bla(VIM2). Pathogenicity island-borne virulence genes were harbored by 9% NFGN isolates. These findings in conjunction with frequent early colonization by Bcc raised serious concerns regarding infection control in Russian CF centers.202437984108
2478100.9650Study on the resistance mechanism via outer membrane protein OprD2 and metal β-lactamase expression in the cell wall of Pseudomonas aeruginosa. The aim of the present study was to evaluate the imipenem-resistant mechanism via the outer membrane protein (OMP) OprD2 and metal β-lactamase expression in the cell wall of Pseudomonas aeruginosa. The Pseudomonas aeruginosa was clinically separated and validated by VITEK-2 full-automatic bacteria analyzer. Drug resistance, sensitive antibiotics and minimum inhibitory concentration (MIC) were tested using the drug sensitivity analysis system. The phenotype positive strains of MBL genes were screened using the Kirby-Bauer diffusion method by adding metal ion-chelating agent EDTA on the imipenem susceptibility paper. IMP-1, VIM-1 and SPM metaloenzyme genes were tested by polymerase chain reaction (PCR)-telomeric repeat amplification protocol (TRAP). The OMP OprD2 genes were tested by PCR-TRAP, and the protein expression was tested using western blot analysis. The location of OMP OprD2 was confirmed using the sodium salicylate inhibition test. The results showed that 80 portions (40%) of MBL-positive strains were screened out of 200 specimens. Imipenem-resistant Pseudomonas aeruginosa (IRPA) and MIC values were significantly higher than quality control bacteria and control bacteria (P<0.05). A total of 35 cases with IMP-1 positive, 20 with VIM-1 positive, 16 with SPM positive, 5 with 2 positive genes and 4 with 3 positive genes were screened among MBL positive strains. A total of 150 portions (75%) of OprD2 deficiencies were screened from 200 specimens. The standard strains and sensitive strains showed OprD2 protein bands at 45 kDa while no OprD2 protein bands appeared in OprD2 deficiency strains. It was in accordance with gene detection. In conclusion, OMP OprD2 deficiency and MBL phenotype positivity may be important mechanisms of IRPA.201627882088
1455110.9650Resistance to bacterial infection, complication occurring after cardiac surgery. To analyze the occurrence of resistant bacterial infection in patients undergoing cardiac surgery hospitalized in the surgical specialty hospital, in Erbil city, Iraq. A prospective study was done on a total of 138 patients operated and hospitalized in an intensive care unit and surgical wards. Bacterial isolates identification was done according to cultural characteristics, microscopic examination, some biochemical tests, analytic Profile Index 20E& API Staph, confirmed with VITEK® 2 compact system (BioMérieux). Antimicrobial susceptibility for disc diffusion tested to 17 antimicrobial agents. Resistance isolates were confirmed phenotypically for carbapenemase by Rapidec Carba NP Test (bioMe´rieux SA, Marcy-l'E´toile, France) for ESBLs producers by ESBL screening test VITEK 2 system. Molecularly blaIMP blaTEM, blaKPC, AmpC and blaCTX-M were detected by PCR. In 134 patients, 28.3% of patients got infected post-operatively. The most frequent source of isolation was from ICU patients (75%). Isolated bacteria included gram-positive 29 (54.7%) and gram-negative bacteria 24 (45.3%). Most frequently:  Staphylococcus aureus (24.4%), each of pseudomonas aeroginosa, Klebsiella pneumonia (15.1%), Streptococcus spp. (11.3%), Escherichia coli (9.4%). Whereas included Coagulase Negative Staphylococci species (CoNS) (13.2%) and Enterococci species (5.7) Statistical analysis showed significantly higher sensitive isolates as compared with resistance isolates. Resistance to Carbapenems calss was 18.9% and Cephalosporins class 41.5% of isolates. The antimicrobial resistance pattern indicated that MDR bacterial isolates (81.1%) were widespread. Of the 34 phenotypically ESBL positive isolates, the ESBL genes (AmpC, blaCTX-M, and blaTEM) were amplified in 7(20.6), 6(17.6) and 6(17.6) isolates respectively. Out of 8 K. pneumonia (37.5%) harboring both blaAmpC and bla-CTX-M genes, while 6(75%) carries blaTEM. The blaCTX-M gene was found in only 1 (12.5%) out of 8 isolates of P. aeruginosa. While blaAmpC genotyping revealed that 1(7.7%) out of 13 Staph. aureus isolates were harboring it. Finally, 3(60%) out of 5 E. coli isolates harboring both AmpC and bla-CTX-M genes. Cardiac surgery patients wound show increasingly emerging strains of ESBL-producing gram-negative bacteria K. pneumonia, P. aeruginosa and E. coli especially patients prolonged in the intensive care unit.202034174972
1454120.9649OCCURRENCE OF AMINOGLYCOSIDES RESISTANCE GENES ACC(6)-IB AND ACC(3)-II AMONG GRAM-NEGATIVE ISOLATES CAUSING URINARY TRACT INFECTION IN PEDIATRIC PATIENTS, NAJAF, IRAQ. OBJECTIVE: The aim: The aim of the study was to detect the antimicrobial susceptibility patterns and frequency of aminoglycosides resistance genes of Gram-negative bacteria isolated from pediatric patient with UTI. PATIENTS AND METHODS: Materials and methods: The study has been performed with a total of 500 urine specimens collected from pediatric patients under the age of 18 year suspected with UTI, admitted to hospitals in Al-Najaf province/Iraq during the period from November 2018 to March 2019. RESULTS: Results: A total of 500 urine specimens had been tested, 120 (24%) had signifficant bacteriuria, while there 380 (76%) had non-signi!cant bacteriuria. Escherichia coli represent about 70 (68.2%) followed by followed by 23 (22.5%) K. pneumoniae, 5 (4.9%) P. aeruginosa, 2 (1.9%) Proteus spp., 1 (0.9%) Enterobacter spp. and 1 (0.9%) Oligella uratolytic. The antimicrobial susceptibility profile of 102 Gram-negative isolates, revealed that 59 (58%) were multidrug resistant (MDR) and 38(37%) were extensive drug resistant (XDR). The PCR results of aminoglycosides resistance showing that 23 (74.1%) Gram-negative isolates had acc(6')-Ib gene and 12 (38.7%) Gram-negative isolates acc(3')-II gene. CONCLUSION: Conclusions: A high frequency of multi-drug resistance and extensive-drug resistance of isolates were recognized, and an alarming percentage of amino-glycosides resistance to acc(6')-Ib and acc(3')-II.202337010165
1405130.9648The threat of carbapenem resistance in Eastern Europe in patients with decompensated cirrhosis admitted to intensive care unit. BACKGROUND: Multidrug-resistant organisms are an increasing concern in patients with decompensated cirrhosis. AIM: We aimed to evaluate the prevalence of infections with carbapenem-resistant Enterobacteriaceae in patients with decompensated cirrhosis. METHODS: Patients with decompensated cirrhosis admitted to ICU were included. The isolated Enterobacteriaceae strains were tested for carbapenemase-producing genes using the Roche LightMix® Modular VIM/IMP/NDM/GES/KPC/OXA48-carbapenemase detection kit. RESULTS: 48 culture-positive infections were registered in 75 patients with acutely decompensated cirrhosis. Thirty patients contracted a second infection. 46% of bacteria isolated at admission and 60% of bacteria responsible for infections identified during ICU-stay were multiresistant. ESBL+ Enterobacteriaceae were predominant at admission, while carbapenem-resistance was dominant in both Enterobacteriaceae and Non-Fermenting-Gram-Negative Bacteria responsible for infections diagnosed during hospitalisation. OXA 48 or KPC type carbapenemases were present in 30% of the analyzed Enterobacteriaceae and in 40% of the phenotypically carbapenem-resistant Klebsiella pneumoniae strains. The length of ICU stay was a risk-factor for a second infection (p=0.04). Previous carbapenem usage was associated with occurence of infections with carbapenem-resistant Gram-negative bacteria during hospitalization (p=0.03). CONCLUSION: The prevalence of infections with carbapenem-resistant Enterobacteriaceae is high in patients with decompensated cirrhosis admitted to ICU. Carbapenemase-producing genes in Enterobacteriaceae in our center are bla(OXA-48) and bla(KPC).202235732546
1461140.9648Phenotypic and Genetic Characterization of Carbapenemase and ESBLs Producing Gram-negative Bacteria (GNB) Isolated from Patients with Cystic Fibrosis (CF) in Tehran Hospitals. BACKGROUND: Cystic Fibrosis (CF) is an autosomal recessive genetic disorder in white populations caused by mutation in a gene that encodes Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein. Since frequent respiratory tract infections are the major problem in patients with CF, obligation to identify the causative bacteria and determining their antibiotic resistance pattern is crucial. The purpose of this project was to detect Gram-negative bacteria (GNB) isolated from sputa of CF patients and to determine their antibiotic resistance pattern. MATERIALS AND METHODS: The sputum of 52 CF patients, treated as inpatients at hospitals in Tehran, was obtained between November 2011 and June 2012. Samples cultured in selective and non-selective media and GNB recognized by biochemical tests. Antimicrobial susceptibility testing to cephalosporins, aminoglycosides and carbapenems was performed by disk diffusion method and MICs of them were measured. For phenotypic detection of carbapenemase and ESBLs production, the Modified Hodge test, double disk synergy test and the combined disk methods were performed. Subsequently, the genes encoding the extended spectrum beta-lactamases (blaPER, blaCTX-M) and carbapenemases (blaIMP-1, blaGES, blaKPC, blaNDM, blaVIM-1, blaVIM-2, blaSPM, blaSIM) in Gram negative bacteria were targeted among the resistant isolates by using PCR. PFGE was used to determine any genetic relationship among the Pseudomonas aeruginosa isolated from these patients. RESULTS: Fifty five GNB were isolated from 52 sputum samples including Pseudomonas aeruginosa, Klebsiella ozaenae, Alcaligenes xylosoxidans, Achromobacter denitrificans, Klebsiella pneumonia and Stenotrophomonas maltophilia. The rates of resistance to different antibiotic were as follows: cefixime (%80), ceftriaxone (%43), ceftazidime (%45) and meropenem (%7). The prevalence of genes encoding the ESBLs and Carbapenemases among the the phenotypically positive strains were as follows: blaCTX-M (19), blaIMP-1 (2), blaVIM-1 (2) and blaVIM-2 (3) genes respectively. No other genes were detected. PFGE analysis revealed 8 genotypes. Six isolates had mutually 3 similar patterns. CONCLUSION: This study showed the existence of important ESBLs and carbapenemases genes among the GNB isolated from patients with CF. Continuous surveillance of ESBLs and Carbapenemases, also identification of their types, in bacteria isolated from these patients have an important clinical impact, since, it can often provide valuable information for effective infection control measures and for the choice of appropriate antimicrobial therapy.201424596716
2172150.9648Detection of blaPER-1 & blaOxa10 among imipenem resistant isolates of Pseudomonas aeruginosa isolated from burn patients hospitalized in Shiraz Burn Hospital. BACKGROUND AND OBJECTIVES: Pseudomonas aeruginosa is one of the most important Gram negative opportunistic bacteria which causes infection among burn patients. Resistance to the antibiotics in this group of bacteria is increased due to the activity of extended spectrum β-lactamase (ESBLs) genes. In the current study, we investigated the prevalence of two genes (blaPER-1 & blaOxa10 ) related β-lactamase genes among imipenem resistance clinical isolates of P. aeruginosa in hospitalized patients. MATERIALS AND METHODS: From May 2010 to March 2011, 270 P. aeruginosa isolated from hospitalized burned patients' wounds in Shiraz Burn Hospital, were tested for Imipenem resistance by disk diffusion method. Presence of ESBLs exo-enzyme, blaPER-1 and blaOxa10 genes were also evaluated in the resistant isolate. RESULTS: 210 (77.7%) of 270 P. aeruginosa isolates were resistant to imipenem. blaPER-1 and blaOxa10 were detected among 168 (80.0%) of imipenem resistant isolates. Furthermore, 160 (76.2%) of them had blaOxa10 gene and 84 (40.0%) of them had blaPER-1 while 63 (30.0%) resistant isolates contained both genes simultaneously. CONCLUSION: This study showed a high prevalence of blaPER-1 and blaOxa10 genes in hospitalized burn patients in south west of Iran. Therefore, it's highly recommended to perform such tests routinely to evaluate the resistance pattern in order to better antibiotic selection in the burned patients.201526644867
2170160.9647Drug resistance in bacteria isolated from patients presenting with wounds at a non-profit Surgical Center in Phnom Penh, Cambodia from 2011-2013. BACKGROUND: Emerging antibiotic resistance amongst clinically significant bacteria is a public health issue of increasing significance worldwide, but it is relatively uncharacterized in Cambodia. In this study we performed standard bacterial cultures on samples from wounds at a Non-Governmental-Organization (NGO) Hospital in Phnom Penh, Cambodia. Testing was performed to elucidate pathogenic bacteria causing wound infections and the antibiotic resistance profiles of bacterial isolates. All testing was performed at the Naval Medical Research Unit, No.2 (NAMRU-2) main laboratory in Phnom Penh, Cambodia. METHODS: Between 2011-2013, a total of 251 specimens were collected from patients at the NGO hospital and analyzed for bacterial infection by standard bacterial cultures techniques. Specimens were all from wounds and anonymous. No specific clinical information accompanied the submitted specimens. Antibiotic susceptibility testing, and phenotypic testing for extended-spectrum beta-lactamase (ESBL) were performed and reported based on CLSI guidelines. Further genetic testing for CTX-M, TEM and SHV ESBLs was accomplished using PCR. RESULTS: One-hundred and seventy-six specimens were positive following bacterial culture (70 %). Staphlycoccus aureus was the most frequently isolated bacteria. Antibiotic drug resistance testing revealed that 52.5 % of Staphlycoccus aureus isolates were oxacillin resistant. For Escherichia coli isolates, 63.9 % were ciprofloxacin and levofloxacin resistant and 96 % were ESBL producers. Resistance to meropenem and imipenem was observed in one of three Acinetobacter spp isolates. CONCLUSIONS: This study is the first of its kind detailing the antibiotic resistance profiles of pathogenic bacteria causing wound infections at a single surgical hospital in Cambodia. The reported findings of this study demonstrate significant antibiotic resistance in bacteria from injured patients and should serve to guide treatment modalities in Cambodia.201528883936
1438170.9647Prevalence and molecular characterization of carbapenemase-producing gram-negative bacteria from a university hospital in China. BACKGROUND: The increasing emergence of carbapenem resistance in gram-negative bacteria associated with carbapenemase prompted the initiation of this study. METHODS: A total of 3139 gram-negative bacteria were recovered from a 3380-bed university hospital in Wenzhou during 2008 and 2012. Antimicrobial susceptibility was determined using the VITEK2 Compact System and agar dilution method. The phenotype and genotype of carbapenemase were demonstrated using the modified Hodge test, PCR and sequencing. A conjugation experiment was performed to reveal the transferability of resistant genes. The location of the carbapenemase gene was studied by plasmid analysis and southern blot hybridization. Clonal relatedness of the isolates was investigated by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). RESULTS: Overall, 751 of 3139 isolates (71/2055 Enterobacteriaceae, 510/620 Acinetobacter baumannii and 170/464 Pseudomonas aeruginosa) exhibited resistance to carbapenem. Carbapenemase-encoding genes were detected in 70.4% (50/71) of carbapenem-resistant Enterobacteriaceae, including blaKPC (80%) and blaIMP (20%). All A. baumannii subjected to genotype analysis were positive for blaOXA-51-like and co-harboured blaOXA-23-like (80.4%) and blaIMP (7.8%). ISAba1 was found upstream of blaOXA-23-like and blaOXA-51-like. Eight and seven strains of 170 P. aeruginosa carried blaIMP and blaVIM, respectively. PFGE analysis identified at least one dominant genotype in certain species. Four KPC-2-producing Klebsiella pneumoniae belonged to the same sequence type ST11. The plasmids carrying blaKPC were successfully transferred into recipient strains. CONCLUSION: This study highlights the challenge of increasing prevalence of carbapenem resistance associated with carbapenemase genes and dissemination of epidemic clones in Wenzhou, China.201626463362
1462180.9647Phenotypic synergy testing of ceftazidime-avibactam with aztreonam in a university hospital having high number of metallobetalactamase producing bacteria. BACKGROUND: Ceftazidime-avibactam combination with aztreonam and role of rapid synergy reporting has not been widely evaluated. Also the synergy correlation with various betalactamases has not been widely studied. METHODS: We studied phenotypic synergy testings and molecular detection of betalactamases in our university hospital where we have large number of mellatobetalactmase producing bacteria. We tested two phenotypic synergy methods for ceftazidime-avibactam with aztreonam (Disc-E strip method, E strip-Agar method) for rapid reporting to clinicians (153 isolates). The treatment (colistin, ceftazidime-avibactam, ceftazidime-avibactam with aztreonam) was guided as indicated in the synergy testings. The resistance genes in bacteria were identified by polymerase chain reaction (PCR) and correlated with synergy results. RESULTS: The highest synergy was seen in Klebsiella pneumoniae by Disc-E strip and E strip-Agar method (86% and 84% respectively). About 70% of Pseudomonas aeruginosa and 29% of Escherichia coli showed synergy. Molecular methods revealed multiple resistance gene combinations and bla(NDM) (96%) was predominant gene in isolates showing synergy. Among isolates that were sensitive to ceftazidime-avibactam, the predominant genes were bla(OXA-48) and bla(IMP.) Rapid laboratory reporting led to proper utilization of antibiotic combinations. CONCLUSIONS: Ceftazidime-avibactam and aztreonam rapid synergy testing will be highly beneficial in treatment of infections by metallobetalactamase producing resistant bacteria, especially K. pneumoniae and P. aeruginosa.202032628575
1538190.9646KPC-2 allelic variants in Klebsiella pneumoniae isolates resistant to ceftazidime-avibactam from Argentina: bla(KPC-80), bla(KPC-81), bla(KPC-96) and bla(KPC-97). Ceftazidime-avibactam (CZA) therapy has significantly improved survival rates for patients infected by carbapenem-resistant bacteria, including KPC producers. However, resistance to CZA is a growing concern, attributed to multiple mechanisms. In this study, we characterized four clinical CZA-resistant Klebsiella pneumoniae isolates obtained between July 2019 and December 2020. These isolates expressed novel allelic variants of bla(KPC-2) resulting from changes in hotspots of the mature protein, particularly in loops surrounding the active site of KPC. Notably, KPC-80 had an K269_D270insPNK mutation near the Lys270-loop, KPC-81 had a del_I173 mutation within the Ω-loop, KPC-96 showed a Y241N substitution within the Val240-loop and KPC-97 had an V277_I278insNSEAV mutation within the Lys270-loop. Three of the four isolates exhibited low-level resistance to imipenem (4 µg/mL), while all remained susceptible to meropenem. Avibactam and relebactam effectively restored carbapenem susceptibility in resistant isolates. Cloning mutant bla(KPC) genes into pMBLe increased imipenem MICs in recipient Escherichia coli TOP10 for bla(KPC-80), bla(KPC-96), and bla(KPC-97) by two dilutions; again, these MICs were restored by avibactam and relebactam. Frameshift mutations disrupted ompK35 in three isolates. Additional resistance genes, including bla(TEM-1), bla(OXA-18) and bla(OXA-1), were also identified. Interestingly, three isolates belonged to clonal complex 11 (ST258 and ST11) and one to ST629. This study highlights the emergence of CZA resistance including unique allelic variants of bla(KPC-2) and impermeability. Comprehensive epidemiological surveillance and in-depth molecular studies are imperative for understanding and monitoring these complex resistance mechanisms, crucial for effective antimicrobial treatment strategies. IMPORTANCE: The emergence of ceftazidime-avibactam (CZA) resistance poses a significant threat to the efficacy of this life-saving therapy against carbapenem-resistant bacteria, particularly Klebsiella pneumoniae-producing KPC enzymes. This study investigates four clinical isolates exhibiting resistance to CZA, revealing novel allelic variants of the key resistance gene, bla(KPC-2). The mutations identified in hotspots surrounding the active site of KPC, such as K269_D270insPNK, del_I173, Y241N and V277_I278insNSEAV, prove the adaptability of these pathogens. Intriguingly, low-level resistance to imipenem and disruptions in porin genes were observed, emphasizing the complexity of the resistance mechanisms. Interestingly, three of four isolates belonged to clonal complex 11. This research not only sheds light on the clinical significance of CZA resistance but also shows the urgency for comprehensive surveillance and molecular studies to inform effective antimicrobial treatment strategies in the face of evolving bacterial resistance.202438319084