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621200.9908Strain differences in the susceptibility and resistance of Pasteurella multocida to phagocytosis and killing by rabbit polymorphonuclear neutrophils. The interactions of 2 capsular serotype A and 4 serotype D strains of Pasteurella multocida with rabbit polymorphonuclear neutrophils (PMN) were compared in vitro, using a PMN phagocytic and bactericidal assay. Bacteria and rabbit PMN were incubated for 15 minutes. The suspensions were subjected to differential centrifugation and the percentage of phagocytosis (cell association) was determined from the number of viable noncell-associated bacteria. The cell pellets and the associated bacteria were resuspended and PMN bactericidal activity was calculated from the number of remaining viable cell-associated bacteria at 45 and 75 minutes after the start of the assay. Test bacteria were not opsonized or were opsonized with immune serum containing active complement. One type A strain was ingested and killed by PMN in the presence and absence of opsonins. The 5 remaining strains were resistant to PMN killing, but only the type A strain resisted phagocytosis. Resistance of the type A strain was attributed to the hyaluronic acid capsule, since pretreatment of the bacteria with hyaluronidase rendered opsonized bacteria susceptible to ingestion and killing. The pattern of resistance of the 4 type D strains was different from that of the resistant type A strain. Both opsonized and nonopsonized type D bacteria became cell associated, but none were killed by PMN. The mechanism of resistance of these 4 strains to PMN bactericidal activity is currently unknown.19846742581
374010.9907Stp1 Loss of Function Promotes β-Lactam Resistance in Staphylococcus aureus That Is Independent of Classical Genes. β-Lactam resistance in Staphylococcus aureus limits treatment options. Stp1 and Stk1, a serine-threonine phosphatase and kinase, respectively, mediate serine-threonine kinase (STK) signaling. Loss-of-function point mutations in stp1 were detected among laboratory-passaged β-lactam-resistant S. aureus strains lacking mecA and blaZ, the major determinants of β-lactam resistance in the bacteria. Loss of Stp1 function facilitates β-lactam resistance of the bacteria.202032179529
621320.9906Use of a Dictyostelium model for isolation of genetic loci associated with phagocytosis and virulence in Klebsiella pneumoniae. Phagocytosis resistance is an important virulence factor in Klebsiella pneumoniae. Dictyostelium has been used to study the interaction between phagocytes and bacteria because of its similarity to mammalian macrophages. In this study, we used a Dictyostelium model to investigate genes for resistance to phagocytosis in NTUH-K2044, a strain of K. pneumoniae causing pyogenic liver abscess that is highly resistant to phagocytosis. A total of 2,500 transposon mutants were screened by plaque assay, and 29 of them permitted phagocytosis by Dictyostelium. In the 29 mutants, six loci were identified; three were capsular synthesis genes. Of the other three, one was related to carnitine metabolism, one encoded a subunit of protease (clpX), and one encoded a lipopolysaccharide O-antigen transporter (wzm). Deletion and complementation of these genes showed that only ΔclpX and Δwzm mutants became susceptible to Dictyostelium phagocytosis, and their complementation restored the phagocytosis resistance phenotype. These two mutants were also susceptible to phagocytosis by human neutrophils and revealed attenuated virulence in a mouse model, implying that they play important roles in the pathogenesis of K. pneumoniae. Furthermore, we demonstrated that clpP, which exists in an operon with clpX, was also involved in resistance to phagocytosis. The transcriptional profile of ΔclpX was examined by microarray analysis and revealed a 3-fold lower level of expression of capsular synthesis genes. Therefore, we have identified genes involved in resistance to phagocytosis in K. pneumoniae using Dictyostelium, and this model is useful to explore genes associated with resistance to phagocytosis in heavily encapsulated bacteria.201121173313
580130.9906Antibiotic resistance: Evaluation of levofloxacin treatment in acute respiratory tract infections cases at the Tasikmalaya City Health Center, Indonesia. Acute respiratory tract infections (ARTIs) are an acute inflammation of the upper and lower respiratory tract caused by the infection of microorganisms or bacteria, viruses, without or accompanied by inflammation of the lung parenchyma. The use of antibiotics is one way to treat respiratory diseases. This study aims to determine the level of resistance of levofloxacin antibiotics to clinical isolates from ARTIs patients at the Tasikmalaya Health Center, Indonesia. The stages of the research included rejuvenation of clinical single isolates from ARTIs patients, identification of bacteria, and antibiotic resistance testing using the paper-disc method. The results of resistance tests from 142 single clinical isolates of acute respiratory infections showed that levofloxacin antibiotics had high levels of resistance of 50.0%, 30.95% of resistance with intermediate levels, and 19.04% were still sensitive. Bacterial identification test results showed bacteria that have been resistant to levofloxacin are from the genus Haemophillus, Streptococcus, Corynebacterium, Staphylococcus, and Bordetella. Treatment of ARTIs with the antibiotic levofloxacin shows that there has been a relatively large resistance, where the results of the identification of all bacteria showed the bacteria that cause ARTIs.202033102193
621140.9905Natural resistance to salmonellae in mice: control by genes within the major histocompatibility complex. Determinations of 50% lethal dose (LD50) values in H-2 congenic B10 lines showed that late-emerging resistance (postimmune response phase) to salmonellae of intermediate virulence was less in H-2b and H-2d than in H-2a, H-2k, and H-2f mice. Association of resistance to H-2 was confirmed by backcross analysis, and LD50 determinations on H-2 recombinant haplotype strains showed that resistance maps to the I-E subregion. Bacterial growth curves in liver and spleen showed that susceptible mice carried bacteria for longer in the reticuloendothelial system than did resistant mice and that susceptible mice showed greater splenomegaly. Association of resistance and susceptibility to H-2 was not different when sister transductant salmonellae expressing somatic antigens O4 and O9 were used. Thus a gene(s) within the major histocompatibility complex controls natural resistance to salmonellae in mice by influencing the ability to clear bacteria from the reticuloendothelial system in the later phase of the infection, and the immunodominant O antigen cannot be solely involved.19852413142
538350.9904Draft genome sequence of Acinetobacter haemolyticus strain MUWRP1017 isolated from the pus of a female inpatient at Bwera General Hospital in Uganda. The bacterium Acinetobacter haemolyticus, with a genome size of 3.4 Mb, was isolated from a pus swab of a wound on the left lower limb above the ankle joint of a female patient. This strain carries the antimicrobial resistance genes cephalosporinase blaADC-25, oxallinase blaOXA-264, floR, and sul2 and other resistance and virulence genes.202439162454
147360.9903Evaluation 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
234170.9903Effect of Salicylic Acid on the gene expression of FnbA and FnbB genes in Staphylococcus hominis. BACKGROUND: Staphylococcus hominis is an opportunistic pathogen that expresses surface proteins, which are adhesive proteins that play a major role in biofilm formation. Biofilm is a protective layer that provides S. hominis bacteria with greater antibiotic resistance and promotes its adherence to biomedical surfaces, facilitating its entry into the bloodstream. OBJECTIVE: This research aimed to investigate the activity of Salicylic Acid (SA) and its effect on the gene expression of biofilm genes (FnbA and FnbB genes). METHODS: A total of 150 blood specimens were collected from patients. The specimens were cultured in broth media of the BacT/ALERT® system and subcultured on blood and chocolate agar. Bacteria were detected using the VITEK2 system. FnbA and FnbB genes were detected using PCR. The broth microdilution method performed the minimum inhibitory concentration (MIC) of Salicylic acid (SA) on S. hominis isolates with both genes. Detection of the gene expression levels of FnbA and FnbB genes was assessed using Real-Time PCR(RT-PCR). RESULTS: The results showed that out of the 150 specimens collected, 35 were S. hominis. The detection of S. hominis bacteria was performed by PCR amplification of two genes FnbA and FnbB and showed 100% and 17.14% of isolates were positive for genes FnbA and FnbB, respectively. The expression of FnbA and FnbB genes was decreased in samples treated with SA compared with untreated ones. CONCLUSION: In conclusion, there is a significant impact of SA on the prevention of biofilm formation of S. hominis through the suppression of gene expression, specifically FnbA and FnbB. This could enhance susceptibility to antimicrobial treatments. However, more research is required to determine whether SA leads to the selection of resistant bacteria.202438875028
621480.9903Central role of toll-like receptor 4 signaling and host defense in experimental pneumonia caused by Gram-negative bacteria. Toll-like receptor 4 (TLR4) has been identified as a receptor for lipopolysaccharide. However, the precise role of TLR4 in regulating gene expression in response to an infection caused by gram-negative bacteria has not been fully elucidated. The role of TLR4 signaling in coordinating gene expression was assessed by gene expression profiling in lung tissue in a mouse model of experimental pneumonia with a low-dose infection of Klebsiella pneumoniae. We analyzed four mouse strains: C57BL/6 mice, which are resistant to bacterial dissemination; 129/SvJ mice, which are susceptible; C3H/HeJ mice, which are susceptible and have defective TLR4 signaling; and their respective control strain, C3H/HeN (intermediate resistance). At 4 h after infection, C57BL/6 and C3H/HeN mice demonstrated the greatest number of genes, with 67 shared induced genes which were TLR4 dependent and highly associated with the resistance phenotype. These genes included cytokine and chemokine genes required for neutrophil activation or recruitment, growth factor receptors, MyD88 (a critical adaptor protein for TLR signaling), and adhesion molecules. TLR4 signaling accounted for over 74% of the gene expression in the C3H background. These data suggest that early TLR4 signaling controls the vast majority of gene expression in the lung in response to an infection caused by gram-negative bacteria and that this subsequent gene expression determines survival of the host.200515618193
19890.9901The Drosophila immune defense against gram-negative infection requires the death protein dFADD. Drosophila responds to Gram-negative infections by mounting an immune response that depends on components of the IMD pathway. We recently showed that imd encodes a protein with a death domain with high similarity to that of mammalian RIP. Using a two-hybrid screen in yeast, we have isolated the death protein dFADD as a molecule that associates with IMD. Our data show that loss of dFADD function renders flies highly susceptible to Gram-negative infections without affecting resistance to Gram-positive bacteria. By genetic analysis we show that dFADD acts downstream of IMD in the pathway that controls inducibility of the antibacterial peptide genes.200212433364
6193100.9901Giardia, Entamoeba, and Trichomonas enzymes activate metronidazole (nitroreductases) and inactivate metronidazole (nitroimidazole reductases). Infections with Giardia lamblia, Entamoeba histolytica, and Trichomonas vaginalis, which cause diarrhea, dysentery, and vaginitis, respectively, are each treated with metronidazole. Here we show that Giardia, Entamoeba, and Trichomonas have oxygen-insensitive nitroreductase (ntr) genes which are homologous to those genes that have nonsense mutations in metronidazole-resistant Helicobacter pylori isolates. Entamoeba and Trichomonas also have nim genes which are homologous to those genes expressed in metronidazole-resistant Bacteroides fragilis isolates. Recombinant Giardia, Entamoeba, and Trichomonas nitroreductases used NADH rather than the NADPH used by Helicobacter, and two recombinant Entamoeba nitroreductases increased the metronidazole sensitivity of transformed Escherichia coli strains. Conversely, the recombinant nitroimidazole reductases (NIMs) of Entamoeba and Trichmonas conferred very strong metronidazole resistance to transformed bacteria. The Ehntr1 gene of the genome project HM-1:IMSS strain of Entamoeba histolytica had a nonsense mutation, and the same nonsense mutation was present in 3 of 22 clinical isolates of Entamoeba. While ntr and nim mRNAs were variably expressed by cultured Entamoeba and Trichomonas isolates, there was no relationship to metronidazole sensitivity. We conclude that microaerophilic protists have bacterium-like enzymes capable of activating metronidazole (nitroreductases) and inactivating metronidazole (NIMs). While Entamoeba and Trichomonas displayed some of the changes (nonsense mutations and gene overexpression) associated with metronidazole resistance in bacteria, these changes did not confer metronidazole resistance to the microaerophilic protists examined here.200919015349
5800110.9901Observation and analysis of the efficacy of dexamethasone in combination with anti-infectious treatment on the pediatric refractory purulent meningitis. To analyze the pathogenic bacteria, feature of drug resistance and the efficacy of dexamethasone as the auxiliary medication in pediatric refractory purulent meningitis (PM). The 190 refractory PM child patients were selected for the culture of pathogenic bacteria and analysis of drug resistance. In total, 190 pathogenic bacteria were detected, consisting of gram-positive bacteria (77.37%). Of the gram-positive bacteria, the resistance rate of patients with staphylococcus epidermidis, streptococcus pneumoniae or Staphylococcus haemolyticus to levofloxacin was 100%, while in gram-negative bacteria, the resistance rate of patients with klebsiella pneumoniae to gentamycin was 100%. In the observation group, patients had a higher effectiveness rate. Besides, patients in the observation group recovered rapidly from the fever and anomalies in cerebral spine fluid and peripheral white blood cells, and the inflammation was greatly improved. However, difference in the incidence rates of adverse reactions of patients between two groups showed no statistical significance. Pediatric refractory PM involves the pathogenic bacteria, mainly including staphylococcus epidermidis and streptococcus pneumoniae, showing a high resistance to levofloxacin, while the auxiliary medication of dexamethasone can improve the efficacy, and inhibit the inflammation.202032173647
3051120.9901Nucleotide sequence of the bacterial streptothricin resistance gene sat3. The nucleotide sequence of the sat3 gene which encodes resistance of enteric bacteria to the antibiotic streptothricin is reported. A protein with a molecular mass of about 23 kDa is expressed from this gene. The sat3 gene is not obviously related to any one of the streptothricin resistance determinants identified so far among Gram-negative or Gram-positive bacteria.19957640311
394130.9901Introduction of bacteriophage Mu into bacteria of various genera and intergeneric gene transfer by RP4::Mu. The host range of coliphage Mu was greatly expanded to various genera of gram-negative bacteria by using the hybrid plasmic RP4::Mu cts, which is temperature sensitive and which confers resistance to ampicillin, kanamycin, and tetracycline. These drug resistance genes were transferred from Escherichia coli to members of the general Klebsiella, Enterobacter, Citrobacter, Salmonella, Proteus, Erwinia, Serratia, Alcaligenes, Agrobacterium, Rhizobium, Pseudomonas, Acetobacter, and Bacillus. Mu phage was produced by thermal induction from the lysogens of all these drug-resistant bacteria except Bacillus. Mu phage and RP4 or the RP4::Mu plasmid were used to create intergeneric recombinant strains by transfer of some genes, including the arylsulfatase gene, between Klebsiella aerogenes and E. coli. Thus, genetic analysis and intergeneric gene transfer are possible in these RP4::Mu-sensitive bacteria.19816450749
2318140.9901Distribution of pathogenic bacteria in lower respiratory tract infection in lung cancer patients after chemotherapy and analysis of integron resistance genes in respiratory tract isolates of uninfected patients. BACKGROUND: We studied the distribution of pathogenic bacteria in lower respiratory tract infection in lung cancer patients after chemotherapy and analyzed the integron resistance genes in respiratory tract isolates of uninfected patients. METHODS: Retrospective analysis was used to select sputum samples from 400 lung cancer patients after chemotherapy admitted in Fuyang People's Hospital from July 2017 to July 2019. Culture, isolation and identification of strains were conducted in accordance with the national clinical examination operating procedures. RESULTS: A total of 134 strains were identified. In 120 patients with pulmonary infection, 114 strains were cultured. Twenty strains of klebsiella pneumoniae were cultured in 280 patients without pulmonary infection. Among the 134 strains, the detection rate of gram-negative bacteria was 79.10%. The first four strains were Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Haemophilus influenzae. The gram-positive bacteria detection rate was 4.47%, mainly Staphylococcus aureus and Streptococcus. The fungus detection rate was 16.42%. The drug sensitivity results showed that the resistance rate of gram-negative bacillus to penicillin and cephalosporin was higher, and were more sensitive to carbapenem, piperacillin tazobactam and cefoperazone sulbactam. Gram-positive cocci were resistant to penicillin, macrolide and clindamycin, and sensitive to linezolid, vancomycin and rifampicin. All strains of fungal culture were candida albicans, which were sensitive to common antifungal drugs. Among the 20 strains of klebsiella pneumoniae cultured in sputum specimens of non-infected patients with lung cancer undergoing chemotherapy, 2 strains were integron-positive strains, and all of them were class I integrons. CONCLUSIONS: Lung cancer patients after chemotherapy have a high resistance to commonly used antimicrobial drugs, so it is necessary to detect the resistance of pathogenic microorganisms in clinical practice. The strains carried by patients with lung cancer without pulmonary infection during chemotherapy can isolate type I integrons, suggesting that the spread of drug resistance at gene level should be closely detected.202032944333
3743150.9901Expression of glycopeptide-resistance gene in response to vancomycin and teicoplanin in the cardiac vegetations of rabbits infected with VanB-type Enterococcus faecalis. VanB-type resistance in enterococci corresponds to resistance to vancomycin but not to resistance to the related glycopeptide teicoplanin, because the vanB gene cluster is activated by the VanR(B)-VanS(B) 2-component regulatory system in response to vancomycin but not to teicoplanin. Mutations in the vanS(B) gene allow for constitutive or teicoplanin-inducible expression of the resistance genes. To analyze in vivo expression of the van genes in rabbits with experimental endocarditis, a VanB-type Enterococcus faecalis with a transcriptional fusion between the P(YB) promoter of resistance genes and the gfpmut1 gene for the green-fluorescent protein in the chromosome was constructed. Rounded heaps containing fluorescent bacteria were detected in vegetation slides from rabbits treated with vancomycin but not in those from control rabbits, revealing induction of a tightly regulated vanB gene cluster. Teicoplanin-resistant mutants were detected as fluorescent bacteria in rabbits treated with teicoplanin. Thus, the reporter system monitored expression of a glycopeptide-resistance gene in vivo at a single-cell level.200414702158
3742160.9901Lipophilic teicoplanin pseudoaglycon derivatives are active against vancomycin- and teicoplanin-resistant enterococci. A selection of nine derivatives of teicoplanin pseudoaglycon were tested in vitro against clinical vancomycin-resistant Enterococcus strains possessing vanA, vanB or both genes. The bacteria were characterized by PCR for the identification of their resistance genes. The tested compounds contain lipoic acid, different carbohydrates and aryl groups as lipophilic moieties. About one-third of the teicoplanin-resistant strains were shown to be susceptible to one or more of the glycopeptide derivatives.201728144040
3741170.9901The fib locus in Streptococcus pneumoniae is required for peptidoglycan crosslinking and PBP-mediated beta-lactam resistance. Penicillin resistance in pneumococci is mediated by modified penicillin-binding proteins (PBPs) that have decreased affinity to beta-lactams. In high-level penicillin-resistant transformants of the laboratory strain Streptococcus pneumoniae R6 containing various combinations of low-affinity PBPs, disruption of the fib locus results in a collapse of PBP-mediated resistance. In addition, crosslinked muropeptides are highly reduced. The fib operon consists of two genes, fibA and fibB, homologous to Staphylococcus aureus femA/B which are also required for expression of methicillin resistance in this organism. FibA and FibB belong to a family of proteins of Gram-positive bacteria involved in the formation of interpeptide bridges, thus representing interesting new targets for antimicrobial compounds for this group of pathogens.200010867238
405180.9900Characterization of a small plasmid (pMBCP) from bovine Pseudomonas pickettii that confers cadmium resistance. This is the first report of isolation of Pseudomonas pickettii from a normal adult bovine duodenum. This organism was one of several bacteria isolated as part of a study to examine cadmium resistance genes (cad(r)) for use in generating transgenic plants to reclaim cadmium-contaminated soils in Kansas. P. pickettii containing a plasmid of 2.2kb (designated pMBCP) grew in Luria-Bertani broth and agar containing up to 800 microM of cadmium chloride and was resistant to 16 antibiotics. Curing the organism of plasmid revealed that antibiotic resistances were not plasmid-mediated. Low-level cadmium resistance was conferred by the plasmid because uncured organism grew significantly better (P<0.05) at 55 microM compared to cured organism. Both plasmid and chromosomal DNA were probed by DNA-DNA hybridization for the presence of known cadmium resistance genes (cadA, cadC, and cadD from Gram-positive (Staphylococcus aureus), but none were detected. The plasmid had one restriction site each for BamHI, PstI, SmaI, and XhoI; two sites each for HincII, SacI, and SphI; and multiple sites for AluI and XcmI. DNA sequence analyses of the cloned and original plasmids showed a GC content of greater than 60% and no homology to any published sequences in the GenBank, European Bioinformatics Institute, or Japanese Genome Net databases. The DNA sequence is contained in GenBank accession number AF144733. Thus, pMBCP offers low-level cadmium resistance to P. picketttii.200312651180
434190.9900Homologous Streptomycin Resistance Gene Present among Diverse Gram-Negative Bacteria in New York State Apple Orchards. The streptomycin resistance gene of Pseudomonas syringae pv. papulans Psp36 was cloned into Escherichia coli and used to develop a 500-bp DNA probe that is specific for streptomycin resistance in P. syringae pv. papulans. The probe is a portion of a 1-kb region shared by three different DNA clones of the resistance gene. In Southern hybridizations, the probe hybridized only with DNA isolated from streptomycin-resistant strains of P. syringae pv. papulans and not with the DNA of streptomycin-sensitive strains. Transposon insertions within the region of DNA shared by the three clones resulted in loss of resistance to streptomycin. Colony hybridization of bacteria isolated from apple leaves and orchard soil indicated that 39% of 398 streptomycin-resistant bacteria contained DNA that hybridized to the probe. These included all strains of P. syringae pv. papulans and some other fluorescent pseudomonads and nonfluorescent gram-negative bacteria, but none of the gram-positive bacteria. The same-size restriction fragments hybridized to the probe in P. syringae pv. papulans. Restriction fragment length polymorphism of this region was occasionally observed in strains of other taxonomic groups of bacteria. In bacteria other than P. syringae pv. papulans, the streptomycin resistance probe hybridized to different-sized plasmids and no relationship between plasmid size and taxonomic group or between plasmid size and orchard type, soil association, or leaf association could be detected.199116348415