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Frontiers in Molecular Biosciences 2021(ACB) complex has emerged as an important nosocomial pathogen and is associated with life-threatening infections, especially among ICU patients, including neonates....
(ACB) complex has emerged as an important nosocomial pathogen and is associated with life-threatening infections, especially among ICU patients, including neonates. Carbapenem resistance in has emerged globally and is commonly mediated by . Clinically significant infections with carbapenem-resistant (CRAB) are a major concern since therapeutic options are limited and associated mortality is high. Early diagnosis of both the pathogen and resistance is important to initiate the optimal therapy and prevent selection of resistance. In the current study, a loop-mediated isothermal amplification (LAMP) assay was developed for rapid detection of the ACB complex and carbapenem resistance mediated by . Universal LAMP primers were designed for the detection of significant members of the ACB complex and carbapenem resistance targeting the ITS 16S-23S rRNA and gene respectively. The optimal conditions for the LAMP assay were standardized for each primer set using standard ATCC strains. The sensitivity of the LAMP assay was assessed based on the limit of detection (LOD) using different DNA concentrations and colony counts. The specificity of LAMP was determined using the non-ACB complex and non-. The results of the LAMP assay were compared with those of polymerase chain reaction (PCR). The optimal temperature for the LAMP assay was 65°C, and the detection time varied with various primers designed. Using the ITS Ab1 primer, LODs of LAMP and PCR assays were 100 pg/μl and 1 ng/μl of DNA concentration and 10 cfu/ml and 10 cfu/ml of colony count, respectively. The LAMP assay was 10- and 10-fold more sensitive than PCR using DNA concentration and colony count, respectively. The LAMP assay was found to be specific for clinically important ACB complex species. The LAMP assay can be applied for early detection of significant species of the ACB complex from clinical samples and their carbapenem-resistant variants. Depending on the emerging pathogen and locally prevalent resistance genes, the LAMP assay can be modified for detection of colonization or infection by various resistant bugs.
PubMed: 34250011
DOI: 10.3389/fmolb.2021.659256 -
BMC Research Notes Mar 2013Infections caused by bacteria such as multidrug resistant (MDR) Acinetobacter spp. and methicillin-resistant Staphylococcus aureus (MRSA) constitute a worldwide...
BACKGROUND
Infections caused by bacteria such as multidrug resistant (MDR) Acinetobacter spp. and methicillin-resistant Staphylococcus aureus (MRSA) constitute a worldwide pandemic. Without gathering information about these strains, we cannot reduce the morbidity and mortality due to infections caused by these notorious bugs.
METHODS
This study was conducted to identify the status of MDR Acinetobacter spp. and MRSA in a tertiary care centre of Nepal. Sputum, endotracheal aspirate and bronchial washing specimens were collected and processed from patients suspected of lower respiratory tract infection following standard microbiological methods recommended by the American Society for Microbiology (ASM). Double disk synergy test method was employed for the detection of extended-spectrum beta-lactamase (ESBL) in Acinetobacter isolates. Methicillin resistance in S. aureus was confirmed by using cefoxitin and oxacillin disks.
RESULTS
Different genomespecies of Acinetobacter were isolated; these consisted of Acinetobacter calcoaceticus baumannii complex and A. lwoffii. Around 95% of Acinetobacter isolates were MDR, while 12.9% were ESBL-producer. Of the total 33 isolates of S. aureus, 26 (78.8%) were MDR and 14 (42.4%) were methicillin resistant.
CONCLUSIONS
A large number of MDR Acinetobacter spp. and MRSA has been noted in this study. The condition is worsened by the emergence of ESBL producing Acinetobacter spp. Hence, judicious use of antimicrobials is mandatory in clinical settings. Moreover, there should be vigilant surveillance of resistant clones in laboratories.
Topics: Acinetobacter baumannii; Anti-Bacterial Agents; Drug Resistance, Bacterial; Drug Resistance, Multiple; Humans; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Nepal
PubMed: 23497675
DOI: 10.1186/1756-0500-6-98 -
Frontiers in Veterinary Science 2019We investigated a collection of strains belonging to the - (ACB) complex obtained from a veterinary clinic with regard to their genetic relatedness, presence of...
We investigated a collection of strains belonging to the - (ACB) complex obtained from a veterinary clinic with regard to their genetic relatedness, presence of antibiotic resistance genes and antimicrobial susceptibility profiles. Fifty-eight ACB-complex strains from animals treated at a veterinary clinic between 2006 and 2017, and seven strains collected from the hospital environment during 2012 were analyzed. Assignment to sequence types (ST) and international complexes (IC) was done by multilocus sequence typing (MLST) according to the Pasteur scheme. Genes encoding carbapenemases, aminoglycoside-modifying enzymes, macrolide-, quinolone- and co-trimoxazole resistance genes, the IS element, virulence associated genes and plasmid associated toxin-antitoxin markers were identified by microarray. Genes encoding -like carbapenemases were amplified by PCR and sequenced. Susceptibility profiles were determined by disc diffusion or by broth microdilution. Among 50 isolates from animals, two predominant clones were observed linked to CC1 ( = 27/54% of the isolates) and CC25 ( = 14/28%), respectively. Strains of IC I harbored , ', and genes. Isolates belonging to CC25 possessed . Six (12%) isolates belonging to CC2 and carrying were also noted. One isolate belonged to CC10 ( ), one to CC149 ( ), the remaining isolate was assigned to ST1220 and possessed . Of six environmental , four (66.7%) belonged to CC25 ( ), one (16.7%) to CC2 ( ) and one to CC3 ( ). Nine isolates (eight from animals and one environmental strain) were non- strains and did not harbor -like genes. None of the isolates carried , , or , and none were resistant to carbapenems. Clonal lineages of the veterinary isolates in our collection are identical to those globally emerging in humans but do not harbor . CC25 may be specific for this particular veterinary clinic environment.
PubMed: 30805352
DOI: 10.3389/fvets.2019.00017 -
Antimicrobial Agents and Chemotherapy Nov 2019We evaluated the activity of minocycline and comparator agents against a large number of ( = 1,289), - species complex ( = 1,081), and complex ( = 101)...
Activity of Minocycline against U.S. Isolates of Acinetobacter baumannii-Acinetobacter calcoaceticus Species Complex, Stenotrophomonas maltophilia, and Burkholderia cepacia Complex: Results from the SENTRY Antimicrobial Surveillance Program, 2014 to 2018.
We evaluated the activity of minocycline and comparator agents against a large number of ( = 1,289), - species complex ( = 1,081), and complex ( = 101) isolates collected from 2014 to 2018 from 87 U.S. medical centers spanning all 9 census divisions. The isolates were collected primarily from hospitalized patients with pneumonia (1,632 isolates; 66.0% overall), skin and skin structure infections (354 isolates; 14.3% overall), bloodstream infections (266 isolates; 10.8% overall), urinary tract infections (126 isolates; 5.1% overall), intra-abdominal infections (61 isolates; 2.5% overall), and other infections (32 isolates; 1.3% overall). Against the - species complex, colistin was the most active agent, exhibiting MIC values at ≤0.5/2 μg/ml and 92.4% susceptibility. Minocycline ranked second in activity, with MIC values at 0.25/8 μg/ml and susceptibility at 85.7%. Activity for these two agents was reduced against extensively drug-resistant and multidrug-resistant isolates of the - species complex. Only two agents showed high levels of activity (susceptibility, >90%) against , minocycline (MIC, 0.5/2 μg/ml; 99.5% susceptible) and trimethoprim-sulfamethoxazole (MIC, ≤0.5/1 μg/ml; 94.6% susceptible). Minocycline was active against 92.8% (MIC, 4 μg/ml) of trimethoprim-sulfamethoxazole-resistant isolates. Various agents exhibited susceptibility rates of nearly 90% against the complex isolates; these were trimethoprim-sulfamethoxazole (MIC, ≤0.5/2 μg/ml; 93.1% susceptible), ceftazidime (MIC, 2/8 μg/ml; 91.0% susceptible), meropenem (MIC, 2/8 μg/ml; 89.1% susceptible), and minocycline (MIC, 2/8 μg/ml; 88.1% susceptible). These results indicate that minocycline is among the most active agents for these three problematic potential pathogen groups when tested against U.S. isolates.
Topics: Acinetobacter Infections; Acinetobacter baumannii; Acinetobacter calcoaceticus; Anti-Bacterial Agents; Burkholderia Infections; Burkholderia cepacia complex; Ceftazidime; Colistin; Drug Resistance, Multiple, Bacterial; Gram-Negative Bacterial Infections; Humans; Microbial Sensitivity Tests; Minocycline; Stenotrophomonas maltophilia; Trimethoprim, Sulfamethoxazole Drug Combination
PubMed: 31427295
DOI: 10.1128/AAC.01154-19 -
IJID Regions Dec 2022Our study aimed to elucidate the clonal diversity of carbapenem-resistant clinical isolates producing NDM-type carbapenemase collected through national surveillance in...
OBJECTIVES
Our study aimed to elucidate the clonal diversity of carbapenem-resistant clinical isolates producing NDM-type carbapenemase collected through national surveillance in Cuba during a 7-year period (2013-19).
METHODS
A total of 199 isolates of spp. from 37 hospitals in 12 provinces were genetically analyzed for their species, carbapenemase genes and genotypes. Sequence type (ST) and OXA-51-like gene type were determined for -positive isolates.
RESULTS
Most isolates (95%) were identified as species of complex, with being the majority. Acquired carbapenemase genes were assigned to or type; the most commonly detected gene was -like (49%), followed by -like (20%) and (15%). Twenty-nine -positive isolates (22 , 2 , 2 , 3 other species) were differentiated into 19 STs, including the most common, ST23. Though NDM genes were mostly typed as , a novel was identified in an ST79 isolate. genes of NDM-positive were discriminated into 10 OXA types, including 2 novel ones.
CONCLUSIONS
Our study indicated the spread of to various clones of and other spp. in Cuba.
PubMed: 36247096
DOI: 10.1016/j.ijregi.2022.08.008 -
Comparative Immunology, Microbiology... Jun 2024To evaluate the frequency of Acinetobacter spp., belonging to both Acinetobacter calcoaceticus-baumannii (ACB) and non-ACB complex, and their antibiotic resistance...
Evidence and antibiotic resistance profiles of clinical Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) and non-ACB complex members in companion animals: A 2020-2022 retrospective study.
To evaluate the frequency of Acinetobacter spp., belonging to both Acinetobacter calcoaceticus-baumannii (ACB) and non-ACB complex, and their antibiotic resistance profiles in veterinary medicine, a three-year (2020-2022) retrospective study was carried out on sick companion animals. Epidemiological data from different clinical canine, feline, and equine samples, were acquired. For each strain, MALDI-TOF MS identification and susceptibility to a panel of 11 antibiotics, by Kirby-Bauer and E-test methods, were performed. Out of 628 bacteriological examinations, 2.5% resulted positive for strains belonging to Acinetobacter genus. Frequencies of 2.3%, 1.9%, and 3% were obtained from both in-visiting and hospitalized dogs, cats, and horses, respectively. Members of ACB-complex accounted for 50% of isolates. Since all strains resulted susceptible to aminoglycosides and polymyxins, no pandrug-resistant (PDR) species were recorded. While 12.5% A. baumannii resulted extensively-drug resistant (XDR), a higher percentage of multidrug-resistant strains was recorded among non-ACB strains (35.5%) than ACB strains (25%). Susceptibility was observed in the same percentage in both groups (62.5%). All ACB strains confirmed their intrinsic resistances. Non-ACB species showed lower resistances against antipseudomonal penicillins plus beta-lactamase inhibitors (P=0.1306), III generation cephalosporins (P=0.0547), and tetracyclines (P=0.0209) than ACB species. Carbapenem-resistance was observed for XDR A. baumannii (12.5%) and, in particular for MDR non-ACB complex members (25%). To our knowledge, A. lactucae represents the first description in two sick dogs in Italy. Furthermore, our results emphasize the role of non-ACB-complex species as important zoonotic pathogens, which could be reservoirs of clinically relevant resistance profiles.
Topics: Animals; Retrospective Studies; Dogs; Cats; Acinetobacter Infections; Horses; Anti-Bacterial Agents; Acinetobacter baumannii; Microbial Sensitivity Tests; Drug Resistance, Multiple, Bacterial; Dog Diseases; Cat Diseases; Pets; Acinetobacter calcoaceticus; Horse Diseases
PubMed: 38663213
DOI: 10.1016/j.cimid.2024.102185 -
Journal of Clinical Microbiology Apr 2010Antimicrobial resistance is depleting the pharmacopeia of agents clinically useful against Gram-negative bacilli. As the number of active agents diminishes, accurate...
Antimicrobial resistance is depleting the pharmacopeia of agents clinically useful against Gram-negative bacilli. As the number of active agents diminishes, accurate susceptibility testing becomes critical. We studied the susceptibilities of 107 isolates of the Acinetobacter baumannii-calcoaceticus complex to amikacin, gentamicin, and tobramycin using disk diffusion, Etest, as well as the Phoenix, Vitek 2, and MicroScan automated systems, and compared the results to those obtained by broth microdilution. Genes encoding aminoglycoside-modifying enzymes (AMEs) were detected by multiplex PCR, and clonal relationships were determined by pulsed-field gel electrophoresis. Tobramycin was the most active aminoglycoside (27.1% of isolates were susceptible). Disk diffusion and Etest tended to be more accurate than the Vitek 2, Phoenix, and MicroScan automated systems; but errors were noted with all methods. The Vitek 2 instrument incorrectly reported that more than one-third of the isolates were susceptible to amikacin (a very major error). Isolates were polyclonal, with 26 distinct strains, and carried multiple AME genes unrelated to the strain type. The presence of the ant(2")-Ia gene was statistically associated with resistance to each aminoglycoside. The AME genotype accounted for the resistance profile observed in a minority of isolates, suggesting the involvement of multiple resistance mechanisms. Hospital pharmacy records indicated the preferential use of amikacin over other aminoglycosides in the burn intensive care unit, where aminoglycoside resistance is prevalent. The resistance in that unit did not correlate with a predominant strain, AME genotype, or total annual aminoglycoside consumption. Susceptibility to tobramycin increased, even though susceptible isolates carried AME genotypes predicting the inactivation of tobramycin. Determination of the relative contribution of multiple concurrent resistance mechanisms may improve our understanding of aminoglycoside resistance in the Acinetobacter baumannii-calcoaceticus complex.
Topics: Acinetobacter baumannii; Acinetobacter calcoaceticus; Adult; Aminoglycosides; Anti-Bacterial Agents; Bacterial Typing Techniques; Diagnostic Errors; Drug Resistance, Bacterial; Genes, Bacterial; Genotype; Humans; Microbial Sensitivity Tests; Young Adult
PubMed: 20107089
DOI: 10.1128/JCM.02006-09 -
PloS One 2014The study aimed to investigate the prevalence and epidemiological characteristics of blaNDM-1 (encoding New Delhi metallo-β-lactamase 1) in Enterobacteriaceae and the...
OBJECTIVES
The study aimed to investigate the prevalence and epidemiological characteristics of blaNDM-1 (encoding New Delhi metallo-β-lactamase 1) in Enterobacteriaceae and the Acinetobacter calcoaceticus-Acinetobacter baumannii complex (ABC) in China from July 2011 to June 2012.
METHODS
PCR was used to screen for the presence of blaNDM-1 in all organisms studied. For blaNDM-1-positive strains, 16S rRNA analysis and Analytical Profile Index (API) strips were used to identify the bacterial genus and species. The ABCs were reconfirmed by PCR detection of blaOXA-51-like. Antibiotic susceptibilities of the bacteria were assessed by determining minimum inhibitory concentration (MIC) of them using two-fold agar dilution test, as recommended by the Clinical and Laboratory Standards Institute (CLSI). Molecular typing was performed using pulsed-field gel electrophoresis (PFGE). S1 nuclease-pulsed-field gel electrophoresis (S1-PFGE) and Southern blot hybridization were conducted to ascertain the gene location of blaNDM-1. Conjugation experiments were conducted to determine the transmission of blaNDM-1-positive strains.
RESULTS
Among 2,170 Enterobacteriaceae and 600 ABCs, seven Enterobacteriaceae strains and two A. calcoaceticus isolates from five different cities carried the blaNDM-1 gene. The seven Enterobacteriaceae strains comprised four Klebsiella pneumoniae, one Enterobacter cloacae, one Enterobacter aerogen and one Citrobacter freundii. All seven were non-susceptible to imipenem, meropenem or ertapenem. Two A. calcoaceticus species were resistant to imipenem and meropenem. Three K. pneumoniae showed the same PFGE profiles. The blaNDM-1 genes of eight strains were localized on plasmids, while one was chromosomal.
CONCLUSIONS
Compared with previous reports, the numbers and species containing the blaNDM-1 in Enterobacteriaceae have significantly increased in China. Most of them are able to disseminate the gene, which is cause for concern. Consecutive surveillance should be implemented and should also focus on the dissemination of blaNDM-1 among gram-negative clinical isolates.
Topics: Acinetobacter baumannii; Acinetobacter calcoaceticus; Adult; Aged; Anti-Bacterial Agents; Bacterial Infections; Blotting, Southern; China; Electrophoresis, Gel, Pulsed-Field; Enterobacteriaceae; Female; Gram-Negative Bacteria; Humans; Male; Microbial Sensitivity Tests; Molecular Typing; RNA, Ribosomal, 16S; Retrospective Studies; Time Factors; beta-Lactamases
PubMed: 25469701
DOI: 10.1371/journal.pone.0113852 -
Biomedical and Environmental Sciences :... Dec 2012Gas chromatography (GC) was used to investigate the cellular fatty acid (CFA) composition of 141 Acinetobacter baumannii and 32 A. calcoaceticus isolates from different...
OBJECTIVE
Gas chromatography (GC) was used to investigate the cellular fatty acid (CFA) composition of 141 Acinetobacter baumannii and 32 A. calcoaceticus isolates from different locations in China and to find chemical markers to differentiate these two closely related bacteria.
METHODS
Whole cell fatty acid methyl esters (FAMEs) were obtained by saponification, methylation, and extraction for GC analysis, followed by a standardized Microbial Identification System (MIS) analysis.
RESULTS
All A. baumannii and A. calcoaceticus strains contained some major fatty acids, namely, 18:1 ω9c, 16:0, Sum In Feature 3, 12:0, 17:1ω8c, 3-OH-12:0, 17:0, Sum In Feature 2, 2-OH-12:0, and 18:0 compounds. Although most of the total CFAs are similar between A. baumannii and A. calcoaceticus strains, the ratios of two pairs of CFAs, i.e., Sum In Feature 3/18:1 ω9c versus 16:0/18:1 ω9c and Sum In Feature 3/18:1 ω9c versus unknown 12.484/18:1 ω9c fatty acids, could differentiate these two closely related bacteria. A. baumannii could be easily classified into two subgroups by plotting some ratios such as Sum In Feature 3/16:0 versus 17:0 and Sum In Feature 3/2-OH-12:0 versus 17:0 fatty acids.
CONCLUSION
The ratios of some CFAs could be used as chemical markers to distinguish A. baumannii from A. calcoaceticus.
Topics: Acinetobacter baumannii; Acinetobacter calcoaceticus; Biomarkers; Fatty Acids; Species Specificity
PubMed: 23228842
DOI: 10.3967/0895-3988.2012.06.014 -
Journal of Bacteriology Feb 1986This report describes the isolation and preliminary characterization of a 5.0-kilobase-pair (kbp) EcoRI DNA restriction fragment carrying the catBCDE genes from...
This report describes the isolation and preliminary characterization of a 5.0-kilobase-pair (kbp) EcoRI DNA restriction fragment carrying the catBCDE genes from Acinetobacter calcoaceticus. The respective genes encode enzymes that catalyze four consecutive reactions in the catechol branch of the beta-ketoadipate pathway: catB, muconate lactonizing enzyme (EC 5.5.1.1); catC, muconolactone isomerase (EC 5.3.3.4); catD, beta-ketoadipate enol-lactone hydrolase (EC 3.1.1.24); and catE, beta-ketoadipate succinyl-coenzyme A transferase (EC 2.8.3.6). In A. calcoaceticus, pcaDE genes encode products with the same enzyme activities as those encoded by the respective catDE genes. In Pseudomonas putida, the requirements for both catDE and pcaDE genes are met by a single set of genes, designated pcaDE. A P. putida mutant with a dysfunctional pcaE gene was used to select a recombinant pKT230 plasmid carrying the 5.0-kbp EcoRI restriction fragment containing the A. calcoaceticus catE structural gene. The recombinant plasmid, pAN1, complemented P. putida mutants with lesions in catB, catC, pcaD, and pcaE genes; the complemented activities were expressed constitutively in the recombinant P. putida strains. After introduction into Escherichia coli, the pAN1 plasmid expressed the activities constitutively but at much lower levels that those found in the P. putida transformants or in fully induced cultures of A. calcoaceticus or P. putida. When placed under the control of a lac promoter on a recombinant pUC13 plasmid in E. coli, the A. calcoaceticus restriction fragment expressed catBCDE activities at levels severalfold higher than those found in fully induced cultures of A. calcoaceticus. Thus there is no translational barrier to expression of the A. calcoaceticus genes at high levels in E. coli. The genetic origin of the cloned catBCDE genes was demonstrated by the fact that the 5.0-kbp EcoRI restriction fragment hybridized with a corresponding fragment from wild-type A. calcoaceticus DNA. This fragment was missing in DNA from an A. calcoaceticus mutant in which the cat genes had been removed by deletion. The properties of the cloned fragment demonstrate physical linkage of the catBCDE genes and suggest that they are coordinately transcribed.
Topics: Acinetobacter; Catechols; Chromosome Deletion; Chromosome Mapping; Cloning, Molecular; Coenzyme A-Transferases; DNA Restriction Enzymes; DNA, Bacterial; Escherichia coli; Gene Expression Regulation; Genes, Bacterial; Nucleic Acid Hybridization; Sulfurtransferases; Transcription, Genetic
PubMed: 3003031
DOI: 10.1128/jb.165.2.557-563.1986