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Journal of Laboratory Physicians Jun 2022The outbreak of ( ) is mainly reported to be a notorious pathogens at health-care settings. It is the major problem on the health-care system with high morbidity...
The outbreak of ( ) is mainly reported to be a notorious pathogens at health-care settings. It is the major problem on the health-care system with high morbidity and mortality rates because of the broad range of antibiotic resistance and lack of understanding the mechanism of developing new antibiotic resistance rapidly. It emphasizes the importance of local surveillance in describing or understanding and predicting microbial resistance patterns so that there will be limited use of antibiotics by developing strategies to control the extensive use of antimicrobial chemotherapy in clinical environment, which is still considered as one of the factors in the emergence of multidrug resistance microorganisms. The study aims to detect the occurrence rate of infections from various clinical samples, identify the resistance levels to different groups of antimicrobial agents, and the occurrence rate of multidrug resistant (MDR) clinical isolates from a tertiary hospital in Durgapur, West Bengal, India. The study was performed in the Department of Microbiology of the IQ City Medical College and Hospital, Durgapur, West Bengal, India, for the 24 months duration, that is, from January 1, 2018 to December 31, 2019. Altogether 15,800 clinical samples consisting of endotracheal tube aspirates, sputum, pus, blood, catheter tips, urine, tissue, and other body fluids were studied. from clinical samples were identified by its characteristic colonies (nonlactose fermenting, glistening, small mucoid colonies), Gram-staining pattern (Gram-negative coccobacillus), and standard biochemical reactions. It was further confirmed in the Department of Microbiology of the Healthworld Hospital, Durgapur, West Bengal, India, by Vitek2 compact system (bioMerieux, Inc., Durham, North Carolina, United States). Antibiotic susceptibility testing was performed using automated broth microdilutions by Vitek2 compact system (bioMerieux, Inc.) and Kirby-Bauer disk diffusion test on Mueller-Hinton Agar (HiMedia). Nonrepetitive 289 were isolated from various clinical samples. A total of 277 (96%) isolates of were MDR strains. was mostly isolated from the intensive care unit department and was found to be the most MDR type in the tertiary care hospital by this study.
PubMed: 35982877
DOI: 10.1055/s-0041-1735583 -
The Journal of General and Applied... Apr 1998The production of lipase from Acinetobacter calcoaceticus LP009, a bacterium isolated from raw milk, was found to be best induced by Tween-80 at 1.0% concentration. It...
The production of lipase from Acinetobacter calcoaceticus LP009, a bacterium isolated from raw milk, was found to be best induced by Tween-80 at 1.0% concentration. It was efficiently secreted, and only a minute amount of activity was detected at the cell surface and intracellularly. A. calcoaceticus LP009 lipase exhibited maximum activity at pH 7.0 and 50 degrees C, and was relatively stable upon storage at pH 5.0 to 7.0 and at 4, 30, or 37 degrees C. The enzyme was found to be inactivated by EDTA suggesting that it was a metalloenzyme. Its activity was reduced by less than 20% with the addition of various ions to reaction mixtures, but long storage with them caused approximately 50% reduction in subsequent reactions under standard conditions. By contrast, the addition of Fe(3+) enhanced activity. The enzyme was highly stable upon storage with 0.1% of Triton X-100, Tween-80 or Tween-20, but highly unstable with various organic solvents tested. PMSF, a serine enzyme inhibitor, and 2-mercaptoethanol, a reducing agent, did not affect enzyme activity. After extraction and transfer, the lipase gene was efficiently expressed in recombinant Aeromonas sobria. This recombinant strain was shown to have increased hydrolyzing efficiency and have high potential for lipid-rich wastewater treatment.
PubMed: 12501281
DOI: 10.2323/jgam.44.139 -
Scientific Reports Jan 2022The carbapenem-resistant Acinetobacter calcoaceticus-baumannii (ACB) complex has become an urgent threat worldwide. Here, we determined antibiotic combinations and the...
The carbapenem-resistant Acinetobacter calcoaceticus-baumannii (ACB) complex has become an urgent threat worldwide. Here, we determined antibiotic combinations and the feasible synergistic mechanisms against three couples of ACB (A. baumannii (AB250 and A10), A. pittii (AP1 and AP23), and A. nosocomialis (AN4 and AN12)). Imipenem with fosfomycin, the most effective in the time-killing assay, exhibited synergism to all strains except AB250. MurA, a fosfomycin target encoding the first enzyme in the de novo cell wall synthesis, was observed with the wild-type form in all isolates. Fosfomycin did not upregulate murA, indicating the MurA-independent pathway (cell wall recycling) presenting in all strains. Fosfomycin more upregulated the recycling route in synergistic strain (A10) than non-synergistic strain (AB250). Imipenem in the combination dramatically downregulated the recycling route in A10 but not in AB250, demonstrating the additional effect of imipenem on the recycling route, possibly resulting in synergism by the agitation of cell wall metabolism. Moreover, heteroresistance to imipenem was observed in only AB250. Our results indicate that unexpected activity of imipenem on the active cell wall recycling concurrently with the presence of heteroresistance subpopulation to imipenem may lead to the synergism of imipenem and fosfomycin against the ACB isolates.
Topics: Acinetobacter Infections; Acinetobacter baumannii; Acinetobacter calcoaceticus; Anti-Bacterial Agents; Bacterial Proteins; Cell Wall; Drug Resistance, Bacterial; Drug Synergism; Fosfomycin; Humans; Imipenem; Microbial Sensitivity Tests
PubMed: 34997148
DOI: 10.1038/s41598-021-04303-7 -
Clinical Microbiology and Infection :... Sep 2012Carbapenem resistance is increasingly being reported among Acinetobacter species, and results mostly from the expression of acquired carbapenem-hydrolysing oxacillinases...
Identification of the naturally occurring genes encoding carbapenem-hydrolysing oxacillinases from Acinetobacter haemolyticus, Acinetobacter johnsonii, and Acinetobacter calcoaceticus.
Carbapenem resistance is increasingly being reported among Acinetobacter species, and results mostly from the expression of acquired carbapenem-hydrolysing oxacillinases (CHDLs). Several Acinetobacter species intrinsically possess chromosomal CHDL genes: Acinetobacter baumannii (bla(OXA-51) ), Acinetobacter radioresistens (bla(OXA-23) ), and Acinetobacter lwoffii (bla(OXA-134) ). We aimed to identify the progenitors of novel CHDL-encoding genes for identification of potential reservoirs. We performed PCR screening using degenerated internal primers designed from a sequence alignment of the known CHDLs (OXA-23, OXA-40, OXA-51, OXA-58, OXA-134, and OXA-143) applied to a collection of 50 Acinetobacter strains belonging to 23 different species. Two strains of Acinetobacter johnsonii, one strain of Acinetobacter calcoaceticus and two strains of Acinetobacter haemolyticus were found to harbour, respectively, the totally novel bla(OXA-211) -like, bla(OXA-213) -like and bla(OXA-214) -like genes. In addition, the complete genomes of those three species available in GenBank, i.e. one A. johnsonii genome, four A. calcoaceticus genomes, and one A. haemolyticus genome, were analysed and found to be positive for the presence of bla(OXA211) -like, bla(OXA-213) -like and bla(OXA-214) -like genes, respectively. The β-lactamases OXA-211, OXA-213 and OXA-214 are diverse, with amino acid identities ranging from 53% to 76%, as compared with the naturally occurring OXA-51-like CHDL from A. baumannii. These β-lactamases showed a peculiar hydrolysis profile, including mostly penicillins and carbapenems. Regarding bla(OXA-23) in A. radioresistens and bla(OXA-134) in A. lwoffii, these genes were not expressed (or expressed at a non-significant level) in their host. Detection of these β-lactamase genes might be used as a useful tool for accurate identification of these Acinetobacter species.
Topics: Acinetobacter; Acinetobacter Infections; Anti-Bacterial Agents; Bacterial Proteins; Base Sequence; Carbapenems; Humans; Microbial Sensitivity Tests; Molecular Sequence Data; Penicillins; Phylogeny; Polymerase Chain Reaction; Sequence Alignment; beta-Lactam Resistance; beta-Lactamases
PubMed: 22128805
DOI: 10.1111/j.1469-0691.2011.03708.x -
Epidemiology and Infection Feb 1995Ribotype, biotype and resistance phenotype were used to characterize 37 Acinetobacter baumannii-A. calcoaceticus complex isolates responsible for nosocomial infections...
Ribotype, biotype and resistance phenotype were used to characterize 37 Acinetobacter baumannii-A. calcoaceticus complex isolates responsible for nosocomial infections in Buenos Aires. Nineteen isolates were recovered from endemic infections at 2 hospitals and 18 represent an intensive care unit outbreak that occurred in a third hospital. By ribotyping isolates were classified into five different clones of A. baumannii biotype 2, 3 of A. baumannii biotype 9, and 3 of Acinetobacter genospecies 13. Combination of the three epidemiological markers permitted categorization of 18 outbreak isolates into four probable strains: 2 A. baumannii biotype 2, named type I, and II, and 2 A. baumannii biotype 9. Type I (15 isolates) was the most prevalent strain at one hospital and was responsible for the outbreak. In conclusion, combined analysis of biotypes, resistance phenotypes, and ribotypes was an accurate approach for epidemiologic investigation of A. baumannii. Furthermore, ribotyping discriminated Acinetobacter genospecies 13 isolates which were phenotypically difficult to type.
Topics: Acinetobacter; Acinetobacter Infections; Acinetobacter calcoaceticus; Argentina; Bacterial Typing Techniques; Cross Infection; Disease Outbreaks; Drug Resistance, Microbial; Humans; Restriction Mapping
PubMed: 7867730
DOI: 10.1017/s0950268800051979 -
Clinical Microbiology and Infection :... Aug 2013To investigate the species distribution within the Acinetobacter calcoaceticus-Acinetobacter baumannii complex and the molecular epidemiology of A. baumannii and...
To investigate the species distribution within the Acinetobacter calcoaceticus-Acinetobacter baumannii complex and the molecular epidemiology of A. baumannii and Acinetobacter nosocomialis, 376 Acinetobacter isolates were collected prospectively from hospitalized patients at 15 medical centres in Germany during three surveillance studies conducted over a 5-year period. Species identification was performed by molecular methods. Imipenem minimum inhibitory concentrations (MIC) were determined by broth microdilution. The prevalence of the most common carbapenemase-encoding genes was investigated by oxacillinase (OXA) -multiplex polymerase chain reaction (PCR). The molecular epidemiology was investigated by repetitive sequence-based PCR (rep-PCR; DiversiLab™). Acinetobacter pittii was the most prevalent Acinetobacter species (n = 193), followed by A. baumannii (n = 140), A. calcoaceticus (n = 10) and A. nosocomialis (n = 8). The majority of A. baumannii was represented by sporadic isolates (n = 70, 50%) that showed unique rep-PCR patterns, 25 isolates (18%) clustered with one or two other isolates, and only 45 isolates (32%) belonged to one of the previously described international clonal lineages. The most prevalent clonal lineage was international clone (IC) 2 (n = 34) and IC 1 (n = 6). According to CLSI, 25 A. baumannii isolates were non-susceptible to imipenem (MIC ≥ 8 mg/L), all of which produced an OXA-58-like or OXA-23-like carbapenemase. The rate of imipenem susceptibility among A. baumannii isolates decreased from 96% in 2005 to 76% in 2009. All other Acinetobacter isolates were susceptible to imipenem. The population structure of carbapenem-susceptible A. baumannii in Germany is highly diverse. Imipenem non-susceptibility was strongly associated with the clonal lineages IC 2 and IC 1. These data underscore the high clonality of carbapenem-resistant A. baumannii isolates.
Topics: Acinetobacter; Acinetobacter Infections; Anti-Bacterial Agents; Bacterial Proteins; Germany; Hospitals; Humans; Imipenem; Microbial Sensitivity Tests; Molecular Epidemiology; Molecular Typing; Polymerase Chain Reaction; Prospective Studies; beta-Lactamases
PubMed: 23034071
DOI: 10.1111/1469-0691.12026 -
International Journal of Nanomedicine 2013The development of nontoxic methods of synthesizing nanoparticles is a major step in nanotechnology to allow their application in nanomedicine. The present study aims to...
Synthesis, optimization, and characterization of silver nanoparticles from Acinetobacter calcoaceticus and their enhanced antibacterial activity when combined with antibiotics.
BACKGROUND
The development of nontoxic methods of synthesizing nanoparticles is a major step in nanotechnology to allow their application in nanomedicine. The present study aims to biosynthesize silver nanoparticles (AgNPs) using a cell-free extract of Acinetobacter spp. and evaluate their antibacterial activity.
METHODS
Eighteen strains of Acinetobacter were screened for AgNP synthesis. AgNPs were characterized using various techniques. Reaction parameters were optimized, and their effect on the morphology of AgNPs was studied. The synergistic potential of AgNPs on 14 antibiotics against seven pathogens was determined by disc-diffusion, broth-microdilution, and minimum bactericidal concentration assays. The efficacy of AgNPs was evaluated as per the minimum inhibitory concentration (MIC) breakpoints of the Clinical and Laboratory Standards Institute (CLSI) guidelines.
RESULTS
Only A. calcoaceticus LRVP54 produced AgNPs within 24 hours. Monodisperse spherical nanoparticles of 8-12 nm were obtained with 0.7 mM silver nitrate at 70°C. During optimization, a blue-shift in ultraviolet-visible spectra was seen. X-ray diffraction data and lattice fringes (d =0.23 nm) observed under high-resolution transmission electron microscope confirmed the crystallinity of AgNPs. These AgNPs were found to be more effective against Gram-negative compared with Gram-positive microorganisms. Overall, AgNPs showed the highest synergy with vancomycin in the disc-diffusion assay. For Enterobacter aerogenes, a 3.8-fold increase in inhibition zone area was observed after the addition of AgNPs with vancomycin. Reduction in MIC and minimum bactericidal concentration was observed on exposure of AgNPs with antibiotics. Interestingly, multidrug-resistant A. baumannii was highly sensitized in the presence of AgNPs and became susceptible to antibiotics except cephalosporins. Similarly, the vancomycin-resistant strain of Streptococcus mutans was also found to be susceptible to antibiotic treatment when AgNPs were added. These biogenic AgNPs showed significant synergistic activity on the β-lactam class of antibiotics.
CONCLUSION
This is the first report of synthesis of AgNPs using A. calcoaceticus LRVP54 and their significant synergistic activity with antibiotics resulting in increased susceptibility of multidrug-resistant bacteria evaluated as per MIC breakpoints of the CLSI standard.
Topics: Acinetobacter calcoaceticus; Anti-Bacterial Agents; Bacteria; Metal Nanoparticles; Microbial Sensitivity Tests; Silver
PubMed: 24235826
DOI: 10.2147/IJN.S48913 -
International Journal of Systematic and... Oct 2021Two isolates of a non-fermenting, Gram-negative bacterial strain were cultured from two throat swabs that were taken from a pair of twins during routine microbiological...
Two isolates of a non-fermenting, Gram-negative bacterial strain were cultured from two throat swabs that were taken from a pair of twins during routine microbiological surveillance screening. As these isolates could not be unambiguously identified using routine diagnostic methods, whole genome sequencing was performed followed by phylogenetic analysis based on the gene sequence and by whole genome datasets. The two strains compose a separate branch within the clade formed by the (ACB) complex with CIP 70.29 as the most closely related species. The average nucleotide identity compared to all other species of the ACB complex was below 94.2% and digital DNA-DNA hybridization values were less than 60%. Biochemical characteristics confirm affiliation to the ACB complex with some specific phenotypic differences. As a result of the described data, a new species is introduced, for which the name sp. nov. is proposed. The type strain is J00019 with a G+C DNA content of 38.8 mol% and it is deposited in the DSMZ Germany (DSM 111094) and CCUG Sweden (CCUG 74625).
Topics: Acinetobacter; Bacterial Typing Techniques; Base Composition; DNA, Bacterial; Genes, Bacterial; Humans; Nucleic Acid Hybridization; Pharynx; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA
PubMed: 34633923
DOI: 10.1099/ijsem.0.005018 -
Research in Microbiology May 2011Acinetobacter genomic species (gen. sp.) 3 and gen. sp. 13TU are increasingly recognized as clinically important taxa within the Acinetobacter...
Genotypic and phenotypic characterization of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex with the proposal of Acinetobacter pittii sp. nov. (formerly Acinetobacter genomic species 3) and Acinetobacter nosocomialis sp. nov. (formerly Acinetobacter genomic species 13TU).
Acinetobacter genomic species (gen. sp.) 3 and gen. sp. 13TU are increasingly recognized as clinically important taxa within the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex. To define the taxonomic position of these genomic species, we investigated 80 strains representing the known diversity of the ACB complex. All strains were characterized by AFLP analysis, amplified rDNA restriction analysis and nutritional or physiological testing, while selected strains were studied by 16S rRNA and rpoB gene sequence analysis, multilocus sequence analysis and whole-genome comparison. Results supported the genomic distinctness and monophyly of the individual species of the ACB complex. Despite the high phenotypic similarity among these species, some degree of differentiation between them could be made on the basis of growth at different temperatures and of assimilation of malonate, l-tartrate levulinate or citraconate. Considering the medical relevance of gen. sp. 3 and gen. sp. 13TU, we propose the formal names Acinetobacter pittii sp. nov. and Acinetobacter nosocomialis sp. nov. for these taxa, respectively. The type strain of A. pittii sp. nov. is LMG 1035(T) (=CIP 70.29(T)) and that of A. nosocomialis sp. nov. is LMG 10619(T) (=CCM 7791(T)).
Topics: Acinetobacter; Acinetobacter baumannii; DNA, Bacterial; Genotype; Molecular Sequence Data; Multilocus Sequence Typing; Phenotype; Phylogeny; RNA, Ribosomal, 16S
PubMed: 21320596
DOI: 10.1016/j.resmic.2011.02.006 -
Journal of Clinical Microbiology Dec 2010A previously established multiplex PCR that identifies to the species level Acinetobacter baumannii and Acinetobacter genomic species 13TU (GS13TU) was expanded to...
A previously established multiplex PCR that identifies to the species level Acinetobacter baumannii and Acinetobacter genomic species 13TU (GS13TU) was expanded to include Acinetobacter calcoaceticus and Acinetobacter genomic species 3.
Topics: Acinetobacter; Acinetobacter Infections; Bacteriological Techniques; DNA Gyrase; DNA Primers; Electrophoresis, Agar Gel; Humans; Polymerase Chain Reaction
PubMed: 20881170
DOI: 10.1128/JCM.01765-10