scholarly journals Efficacy of bacteriophage treatment against carbapenem-resistant Acinetobacter baumannii in Galleria mellonella larvae and a mouse model of acute pneumonia

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Jongsoo Jeon ◽  
Jong-Hwan Park ◽  
Dongeun Yong
Keyword(s):  
Mouse Model ◽  
Acinetobacter Baumannii ◽  
Galleria Mellonella ◽  
Carbapenem Resistant ◽  
Acute Pneumonia

scholarly journals In vivo efficacy of combination of colistin with fosfomycin or minocycline in a mouse model of multidrug-resistant Acinetobacter baumannii pneumonia

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Nam Su Ku ◽  
Su-Hyung Lee ◽  
Young- soun Lim ◽  
Heun Choi ◽  
Jin Young Ahn ◽  
...  
Keyword(s):  
Mouse Model ◽  
Acinetobacter Baumannii ◽  
Synergistic Effects ◽  
Bacterial Load ◽  
Multidrug Resistant ◽  
Therapeutic Options ◽  
Severance Hospital ◽  
Carbapenem Resistant ◽  
Combination Regimens

AbstractUnfortunately, the options for treating multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) infections are extremely limited. Recently, fosfomycin and minocycline were newly introduced as a treatment option for MDR A. baumannii infection. Therefore, we investigated the efficacy of the combination of colistin with fosfomycin and minocycline, respectively, as therapeutic options in MDR A. baumannii pneumonia. We examined a carbapenem-resistant A. baumannii isolated from clinical specimens at Severance Hospital, Seoul, Korea. The effect of colistin with fosfomycin, and colistin with minocycline on the bacterial counts in lung tissue was investigated in a mouse model of pneumonia caused by MDR A. baumannii. In vivo, colistin with fosfomycin or minocycline significantly (p < 0.05) reduced the bacterial load in the lungs compared with the controls at 24 and 48 h. In the combination groups, the bacterial loads differed significantly (p < 0.05) from that with the more active antimicrobial alone. Moreover, the combination regimens of colistin with fosfomycin and colistin with minocycline showed bactericidal and synergistic effects compared with the more active antimicrobial alone at 24 and 48 h. This study demonstrated the synergistic effects of combination regimens of colistin with fosfomycin and minocycline, respectively, as therapeutic options in pneumonia caused by MDR A. baumannii.

scholarly journals Piscidin is Highly Active against Carbapenem-Resistant Acinetobacter baumannii and NDM-1-Producing Klebsiella pneumonia in a Systemic Septicaemia Infection Mouse Model

Marine Drugs ◽  
2015 ◽  
Vol 13 (4) ◽  
pp. 2287-2305 ◽  
Author(s):  
Chieh-Yu Pan ◽  
Jian-Chyi Chen ◽  
Te-Li Chen ◽  
Jen-Leih Wu ◽  
Cho-Fat Hui ◽  
...  
Keyword(s):  
Mouse Model ◽  
Acinetobacter Baumannii ◽  
Klebsiella Pneumonia ◽  
Highly Active ◽  
Carbapenem Resistant

scholarly journals The antimicrobial activity of silver acetate against Acinetobacter baumannii in a Galleria mellonella infection model

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11196
Author(s):  
Eden Mannix-Fisher ◽  
Samantha McLean
Keyword(s):  
Acinetobacter Baumannii ◽  
Bacterial Infections ◽  
Galleria Mellonella ◽  
World Health Organisation ◽  
World Health ◽  
Infection Model ◽  
Silver Acetate ◽  
Selective Toxicity ◽  
Carbapenem Resistant

Background The increasing prevalence of bacterial infections that are resistant to antibiotic treatment has caused the scientific and medical communities to look for alternate remedies aimed at prevention and treatment. In addition to researching novel antimicrobials, there has also been much interest in revisiting some of the earliest therapies used by man. One such antimicrobial is silver; its use stretches back to the ancient Greeks but interest in its medicinal properties has increased in recent years due to the rise in antibiotic resistance. Currently antimicrobial silver is found in everything from lunch boxes to medical device implants. Though much is claimed about the antimicrobial efficacy of silver salts the research in this area is mixed. Methods Herein we investigated the efficacy of silver acetate against a carbapenem resistant strain of Acinetobacter baumannii to determine the in vitro activity of this silver salt against a World Health Organisation designated category I critical pathogen. Furthermore, we use the Galleria mellonella larvae model to assess toxicity of the compound and its efficacy in treating infections in a live host. Results We found that silver acetate can be delivered safely to Galleria at medically relevant and antimicrobial levels without detriment to the larvae and that administration of silver acetate to an infection model significantly improved survival. This demonstrates the selective toxicity of silver acetate for bacterial pathogens but also highlights the need for administration of well-defined doses of the antimicrobial to provide an efficacious treatment.

scholarly journals Lyb-2-4, a unique genomic region of hypervirulent carbapenem-resistant Acinetobacter baumannii

2019 ◽  
Author(s):  
Chao Zheng ◽  
Jinyong Zhang ◽  
Min Zhang ◽  
Zhou Liu ◽  
Yuxin Zhong ◽  
...  
Keyword(s):  
Mouse Model ◽  
Acinetobacter Baumannii ◽  
Multilocus Sequence Typing ◽  
Core Genome ◽  
Medical Intervention ◽  
Genomic Region ◽  
Multi Drug Resistance ◽  
Comparative Genomic ◽  
Low Grade ◽  
Carbapenem Resistant

ABSTRACTAcinetobacter baumannii is an important human pathogen due to its multi-drug resistance, but is usually with low-grade virulence. Although a mouse model revealed different virulence grades of clinical carbapenem-resistant A. baumannii (CRAB) strains, the genetic basis remains unknown. We collected 61 CRAB isolates from intensive care unit of Shenzhen People’s Hospital (Shenzhen, China), and analyzed them used whole genome sequencing (WGS), multilocus sequence typing (MLST) and core genome MLST (cgMLST), transmission chain reconstruction and Comparative genomic tools. A mouse pneumonia model was used to confirm the hypervirulent phenotype. Eleven complex types (CT) were identified based on core genome multilocus sequence typing scheme. CT512 showed higher transmissibility and bloodstream infection rates than other CTs. A genomic region Lyb-2-4 was shared by CT512 and CT2092 but not CT2085. The mortality rates of patient infected with CRAB harboring Lyb-2-4 was significantly higher than those infected with CRAB isolates without Lyb-2-4 (77.8% vs 24.5%, p < 0.01). In the mouse model, the survival rates of strains containing the Lyb-2-4 region (LAC-4, 5122 and 2092) were significantly lower than for strains without Lyb-2-4 (7152, 71517, 20859 and ATCC17978). One open reading frame (ORF) was a marker for the presence of Lyb-2-4, and PCR of a segment of this ORF, designated as hvcT, served as a tag for hypervirulent CRAB. Our study should be very useful in advising the clinician to implement medical intervention earlier, and also making the worldwide surveillance of these hypervirulent CRAB strains easier.IMPORTANCEHypervirulent CRAB strains are expected to pose a threat to human health because infection of these strains is associated with high mortality and multidrug resistance. The rapid hypervirulent CRAB identification assay will facilitate prompt medical intervention. Our findings should provoke surveillance for hypervirulent CRAB strains harboring Lyb-2-4 in other countries. Further research should focus on the mechanism of hypervirulence, the acquisition of this genomic region and the development of control measures to prevent further dissemination.

scholarly journals Characterization of carbapenem-resistant hypervirulent Acinetobacter baumannii strains isolated from hospitalized patients in the mid-south region of China

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jun Li ◽  
Ting Yu ◽  
Yi Luo ◽  
Jing-Yi Peng ◽  
Yu-Jia Li ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Acinetobacter Baumannii ◽  
High Mortality ◽  
Galleria Mellonella ◽  
Opportunistic Pathogen ◽  
Infection Model ◽  
Carbapenem Resistant ◽  
Blood Specimens ◽  
Sequence Types

Abstract Background Acinetobacter baumannii has traditionally been considered an opportunistic pathogen with low virulence. In this study, we characterized the carbapenem-resistant hypervirulent A. baumannii (CR-hvAB) stains isolated from our hospital in mid-south region of China. Results Blood samples collected between January 2017 and May 2019 were used for virulence experiments and biofilm assays of individual carbapenem-resistant A. baumannii (CR-AB) strains, performed using a Galleria mellonella infection model and crystal violet staining method, respectively. CR-AB isolates that induced high mortality in the G. mellonella infection model were subjected to genotyping, susceptibility testing, and clinical data analysis, and the genetic characterization of these isolates was performed by whole-genome sequencing (WGS). Among the 109 CR-AB clinical strains, the survival rate of G. mellonella larvae infected with 7 (6.4%) CR-AB isolates (number of strains with mortality of 0, 10 and 20% was 4, 1, and 2, respectively), was significantly lower than that of A. baumannii ATCC 19606 (100.0%) and the remaining CR-AB isolates (> 80.0%). Consistent with these results, patients infected with these seven isolates had an average 7-day mortality rate of 42.9%, suggesting that the isolates were CR-hvAB. These seven isolates belonged to four sequence types (STs): ST457, ST195, ST369, and ST2088 (a new ST), and mainly ST457 (n = 4). The results of the biofilm study showed that eight strains had powerful biofilm ability (strong [n = 1] and moderate [n = 7] biofilm producers) including these seven CR-hvAB isolates. Conclusions CR-hvAB isolates that induced a high mortality rate were cloned in our hospital, most of which belonged to ST457; thus, monitoring of these strains, particularly ST457, should be strengthened in the future. Meanwhile, A. baumannii, which was isolated from blood specimens and found to powerful biofilm-forming ability, is a probable hvAB isolate.

scholarly journals Virulence Characteristics of Biofilm-Forming Acinetobacter baumannii in Clinical Isolates Using a Galleria mellonella Model

2021 ◽  
Vol 9 (11) ◽  
pp. 2365
Author(s):  
Mahmoud A. F. Khalil ◽  
Fatma A. Ahmed ◽  
Ahmed F. Elkhateeb ◽  
Eman E. Mahmoud ◽  
Mona I. Ahmed ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Galleria Mellonella ◽  
Microtiter Plate ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Icu Patients ◽  
Carbapenem Resistant ◽  
Hospital Acquired

Acinetobacter baumannii is a Gram-negative coccobacillus responsible for severe hospital-acquired infections, particularly in intensive care units (ICUs). The current study was designed to characterize the virulence traits of biofilm-forming carbapenem-resistant A. baumannii causing pneumonia in ICU patients using a Galleria mellonella model. Two hundred and thirty patients with hospital-acquired or ventilator-associated pneumonia were included in our study. Among the total isolates, A. baumannii was the most frequently isolated etiological agent in ICU patients with pneumonia (54/165, 32.7%). All A. baumannii isolates were subjected to antimicrobial susceptibility testing by the Kirby–Bauer disk diffusion method, while the minimum inhibitory concentrations of imipenem and colistin were estimated using the broth microdilution technique. The biofilm formation activity of the isolates was tested using the microtiter plate technique. Biofilm quantification showed that 61.1% (33/54) of the isolates were strong biofilm producers, while 27.7% (15/54) and 11.1% (6/54) showed moderate or weak biofilm production. By studying the prevalence of carbapenemases-encoding genes among isolates, blaOXA-23-like was positive in 88.9% of the isolates (48/54). The BlaNDM gene was found in 27.7% of the isolates (15/54 isolates). BlaOXA-23-like and blaNDM genes coexisted in 25.9% (14/54 isolates). Bap and blaPER-1 genes, the biofilm-associated genes, coexisted in 5.6% (3/54) of the isolates. For in vivo assessment of A. baumannii pathogenicity, a Galleria mellonella survival assay was used. G. mellonella survival was statistically different between moderate and poor biofilm producers (p < 0.0001). The killing effect of the strong biofilm-producing group was significantly higher than that of the moderate and poor biofilm producers (p < 0.0001 for each comparison). These findings highlight the role of biofilm formation as a powerful virulence factor for carbapenem-resistant A. baumannii that causes pneumonia in the ICU.

scholarly journals Pathogenicity of Clinical Acinetobacter baumannii Isolates in a Galleria mellonella Host Model According toblaOXA-40Gene and Epidemiological Outbreak Status

2013 ◽  
Vol 58 (2) ◽  
pp. 1240-1242 ◽  
Author(s):  
John S. Esterly ◽  
Milena M. McLaughlin ◽  
Michael Malczynski ◽  
Chao Qi ◽  
Teresa R. Zembower ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Patient Outcomes ◽  
Clinical Studies ◽  
Galleria Mellonella ◽  
Content Type ◽  
Content Model ◽  
Carbapenem Resistant ◽  
Poor Patient

ABSTRACTClinical studies have suggested thatblaOXA-40-positiveAcinetobacter baumanniiisolates are associated with poor patient outcomes; however, reasons for unfavorable outcomes are difficult to discern in clinical studies. The objective of this study was to assess the virulence of carbapenem-resistantA. baumanniiaccording toblaOXA-40and epidemiological outbreak status in aGalleria mellonellamodel. Eight isolates ofA. baumanniiwere studied. Nonoutbreak isolates andblaOXA-40-negative isolates more rapidly killed infectedG. mellonella(P< 0.01).

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