Influence of ACB complex genospecies on clinical outcomes in a U.S. hospital with high rates of multidrug resistance

Fitzpatrick, Margaret A.; Ozer, Egon A.; Bolon, Maureen K.; Hauser, Alan R.

doi:10.1016/j.jinf.2014.09.004

Cited by 40 publications

(32 citation statements)

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“…Species within the ACB complex differ markedly in the severity of illness they cause and in their resistance to antibiotics (7,13). Accurate identification of Acinetobacter to the species level is becoming increasingly important in the clinical setting.…”

Section: Resultsmentioning

confidence: 99%

“…Compared with non-baumannii ACB complex species, A. baumannii is more frequently multidrug resistant, more often cultured from critically ill patients, and associated with poorer clinical outcomes, likely due to delays in the receipt of appropriate antibiotic therapy (7,13,85). A strain typing method that rapidly identifies bacteria within the ACB complex to the species level and identifies resistance genes would lead to a timelier administration of appropriate antibiotic therapy and, presumably, improved patient outcomes.…”

Section: Figmentioning

confidence: 99%

“…Several studies have shown that these different species within the ACB complex exhibit unique epidemiologic niches, drug resistance patterns, and virulence characteristics within the nosocomial environment (9, 10). In addition, recent studies have demonstrated that patients infected with non-baumannii ACB complex bacteria have fewer comorbidities and improved clinical outcomes than patients with A. baumannii infections (7,(11)(12)(13). Thus, determining the species within the ACB complex that is responsible for an infection has important medical implications.…”

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Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks

2016

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bAcinetobacter baumannii frequently causes nosocomial infections and outbreaks. Whole-genome sequencing (WGS) is a promising technique for strain typing and outbreak investigations. We compared the performance of conventional methods with WGS for strain typing clinical Acinetobacter isolates and analyzing a carbapenem-resistant A. baumannii (CRAB) outbreak. We performed two band-based typing techniques (pulsed-field gel electrophoresis and repetitive extragenic palindromic-PCR), multilocus sequence type (MLST) analysis, and WGS on 148 Acinetobacter calcoaceticus-A. baumannii complex bloodstream isolates collected from a single hospital from 2005 to 2012. Phylogenetic trees inferred from core-genome single nucleotide polymorphisms (SNPs) confirmed three Acinetobacter species within this collection. Four major A. baumannii clonal lineages (as defined by MLST) circulated during the study, three of which are globally distributed and one of which is novel. WGS indicated that a threshold of 2,500 core SNPs accurately distinguished A. baumannii isolates from different clonal lineages. The bandbased techniques performed poorly in assigning isolates to clonal lineages and exhibited little agreement with sequence-based techniques. After applying WGS to a CRAB outbreak that occurred during the study, we identified a threshold of 2.5 core SNPs that distinguished nonoutbreak from outbreak strains. WGS was more discriminatory than the band-based techniques and was used to construct a more accurate transmission map that resolved many of the plausible transmission routes suggested by epidemiologic links. Our study demonstrates that WGS is superior to conventional techniques for A. baumannii strain typing and outbreak analysis. These findings support the incorporation of WGS into health care infection prevention efforts.A n important role of clinical microbiology is to identify relationships between bacterial isolates. At a broad level, phenotypic and genotypic tests are used to categorize bacterial isolates into the same or different species. Within a bacterial species, techniques are used to group isolates into clonal lineages, which are groups of closely related bacteria that share a recent common ancestor but have spread regionally or globally. At a more local level, infection control practitioners must determine whether a group of isolates constitutes a hospital outbreak by ascertaining whether the isolates have a degree of similarity consistent with a common source within the hospital. Once isolates belonging to a hospital outbreak have been identified, similarities and differences between these isolates can be exploited to generate a transmission map to aid in finding the source of the outbreak and in disrupting ongoing pathways of transmission. For some groups of bacteria, such as Acinetobacter, discernment at each level has medically important consequences and therefore must be accomplished by hospital-associated clinical microbiology laboratories.Within the Acinetobacter genus, the Acinetobacter calcoaceticusAcinetobac...

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Section: Resultsmentioning

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Section: Figmentioning

confidence: 99%

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Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks

2016

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“…baumannii complex. For this purpose the application of molecular methods is required 11,12 . Another disturbing problem is the growing antimicrobial resistance among A. baumannii isolates, making management, control, and treatment of infections more and more difficult.…”

Section: Introductionmentioning

confidence: 99%

Cytostatic, cytotoxic, and antibacterial activities of essential oil isolated from Citrus hystrix

Borusiewicz¹,

Trojanowska²,

Paluchowska³

et al. 2017

ScienceAsia

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ABSTRACT:The essential oil obtained from the peel of Citrus hystrix fruits is a colourless or light yellow liquid with a strong citrus scent. It was analysed for its constituents using gas chromatography/mass spectroscopy. The major components of the oil were β-pinene, limonene, terpinen-4-ol, α-pinene, α-terpinene, γ-terpinene, and α-terpineol. The antibacterial activity of C. hystrix essential oil was tested by disc diffusion and serial macrodilution methods against 50 multidrug-resistant Acinetobacter baumannii strains. The results confirmed its good activity expressed by minimal inhibitory concentration values in the range of 0.125-1 µl/ml. The effect on the viability and proliferation of normal human skin fibroblasts (HSF) and the human melanoma cells (WM793 and A375) was also examined. The observed cytostatic and cytotoxic activities were dependent on the dose of tested oil and the incubation time. Melanoma cells (WM793 and A375) were more sensitive to the essential oil from C. hystrix peel than normal cells (HSF). These results suggest a need for more detailed research on its possible use in therapy.

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“…The environmental strain A. calcoaceticus has not been reported to cause infection in humans whilst the other organisms are all of clinical significance (Peleg et al, 2008;Peleg et al, 2012). A recent paper has described increased severity and mortality in bacteraemia patients infected with A. baumannii compared with those infected with A. pitii and A. nosocomialis, emphasising the need for accurate differentiation (Fitzpatrick et al, 2015). However, these four species which together make up the A. calcoaceticus -A. baumannii (Acb) complex are indistinguishable by phenotypic based tests (Peleg et al, 2008;Wang et al, 2013;Lee et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Species identification within Acinetobacter calcoaceticus–baumannii complex using MALDI-TOF MS

Toh

Paterson

Kamolvit

et al. 2015

Journal of Microbiological Methods

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Acinetobacter baumannii, one of the more clinically relevant species in the Acinetobacter genus is well known to be multi-drug resistant and associated with bacteremia, urinary tract infection, pneumonia, wound infection and meningitis. However, it cannot be differentiated from closely related species such as A. calcoaceticus, A. pittii and A. nosocomialis by most phenotypic tests and can only be differentiated by specific, time consuming genotypic tests with very limited use in clinical microbiological laboratories. As a result, these species are grouped into the A.calcoaceticus -A. baumannii (Acb) complex. Herein we investigated the mass spectra of 73 Acinetobacter spp., representing ten different species, using an AB SCIEX 5800 MALDI -TOF MS to differentiate members of the Acinetobacter genus, including the species of the Acb complex. RpoB gene sequencing, 16S rRNA sequencing, and gyrB multiplex PCR were also evaluated as orthogonal methods to identify the organisms used in this study. We found that whilst 16S rRNA and rpoB gene sequencing could not differentiate A. pittii or A. calcoaceticus, they can be differentiated using gyrB multiplex PCR and MALDI -TOF MS. All ten Acinetobacter species investigated could be differentiated by their MALDI -TOF mass spectra.

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Influence of ACB complex genospecies on clinical outcomes in a U.S. hospital with high rates of multidrug resistance

Cited by 40 publications

References 39 publications

Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks

Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks

Cytostatic, cytotoxic, and antibacterial activities of essential oil isolated from Citrus hystrix

Species identification within Acinetobacter calcoaceticus–baumannii complex using MALDI-TOF MS

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