scholarly journals A temperate phage 5W infecting multidrug-resistant Acinetobacter baumannii

Author(s):  
Wenyi Peng ◽  
Fei Zeng ◽  
Zeyuan Jin ◽  
Wanxia Li ◽  
Mingzhuo Zhu ◽  
...  

Abstract We isolated 5W, a temperate phage that infects multidrug-resistant Acinetobacter baumannii from pond water, using an enrichment method that involves the addition of host bacteria. 5W is a long-tailed phage with a narrow host range lysed four of 19 A. baumannii clinical isolates tested, and complete lysis was observed for A. baumannii clinical isolate Ab1. 5W adsorbed rapidly to its Ab1 host and > 80% adsorption was observed after 2 min of mixing. The one-step growth curve showed that 5W has a 20 min latent period and a ~ 100 min rise period, with a burse size of ~ 180 PFU/cell. 5W contains a dsDNA genome 43,032 bp in length, with 61 open reading frames and a GC content of 39.85%. The genome lacks any known virulence and drug resistance genes, but encodes an N-acetyl-β-D-muramidase with numerous positively charged amino acids at its C-terminus that belongs to the GH_108 family. The M/S subunits of the restriction endonuclease are inserted in the lysogenic gene cluster. The first and second halves of the 5W genome are highly homologous with prophages phiABCR01-03 and phiABCR01-02 in the A. baumannii ABCR01 genome, respectively, which suggests that 5W may be a product of recombination between the two prophages.

Author(s):  
Tzu-Ping Ko ◽  
Chi-Hung Huang ◽  
Shu-Jung Lai ◽  
Yeh Chen

Undecaprenyl pyrophosphate (UPP) is an important carrier of the oligosaccharide component in peptidoglycan synthesis. Inhibition of UPP synthase (UPPS) may be an effective strategy in combating the pathogen Acinetobacter baumannii, which has evolved to be multidrug-resistant. Here, A. baumannii UPPS (AbUPPS) was cloned, expressed, purified and crystallized, and its structure was determined by X-ray diffraction. Each chain of the dimeric protein folds into a central β-sheet with several surrounding α-helices, including one at the C-terminus. In the active site, two molecules of citrate interact with the side chains of the catalytic aspartate and serine. These observations may provide a structural basis for inhibitor design against AbUPPS.


2008 ◽  
Vol 52 (11) ◽  
pp. 4115-4120 ◽  
Author(s):  
Raffaele Zarrilli ◽  
Domenico Vitale ◽  
Anna Di Popolo ◽  
Maria Bagattini ◽  
Ziad Daoud ◽  
...  

ABSTRACT We investigated the basis of the carbapenem resistance of 17 multidrug-resistant Acinetobacter baumannii clinical isolates collected from 2004 to 2005 at the Saint George University Hospital in Beirut, Lebanon. A. baumannii isolates were clonally related and were susceptible to colistin and trimethoprim-sulfamethoxazole, susceptible or intermediate to ampicillin-sulbactam and meropenem, and resistant to all other antimicrobials. Conjugation experiments demonstrated that resistance to imipenem could be transferred along with a plasmid containing the carbapenem-hydrolyzing oxacillinase bla OXA-58 gene. The plasmid that we called pABIR was 29,823 bp in size and showed a novel mosaic structure composed of two origins of replication, four insertion sequence (IS) elements, and 28 open reading frames. The bla OXA-58 gene was flanked by IS18 and ISAba3 elements at the 5′ and 3′ ends, respectively. The production of the carbapenem-hydrolyzing oxacillinase OXA-58 was apparently the only mechanism for carbapenem resistance in A. baumannii isolates causing the outbreak at the Lebanese Hospital.


2013 ◽  
Vol 79 (21) ◽  
pp. 6535-6543 ◽  
Author(s):  
H. M. Sharon Goh ◽  
Scott A. Beatson ◽  
Makrina Totsika ◽  
Danilo G. Moriel ◽  
Minh-Duy Phan ◽  
...  

ABSTRACTAcinetobacter baumanniiis a multidrug-resistant pathogen associated with hospital outbreaks of infection across the globe, particularly in the intensive care unit. The ability ofA. baumanniito survive in the hospital environment for long periods is linked to antibiotic resistance and its capacity to form biofilms. Here we studied the prevalence, expression, and function of theA. baumanniibiofilm-associated protein (Bap) in 24 carbapenem-resistantA. baumanniiST92 strains isolated from a single institution over a 10-year period. Thebapgene was highly prevalent, with 22/24 strains being positive forbapby PCR. Partial sequencing ofbapwas performed on the index case strain MS1968 and revealed it to be a large and highly repetitive gene approximately 16 kb in size. Phylogenetic analysis employing a 1,948-amino-acid region corresponding to the C terminus of Bap showed that BapMS1968clusters with Bap sequences from clonal complex 2 (CC2) strains ACICU, TCDC-AB0715, and 1656-2 and is distinct from Bap in CC1 strains. By using overlapping PCR, thebapMS1968gene was cloned, and its expression in a recombinantEscherichia colistrain resulted in increased biofilm formation. A Bap-specific antibody was generated, and Western blot analysis showed that the majority ofA. baumanniistrains expressed an ∼200-kDa Bap protein. Further analysis of three Bap-positiveA. baumanniistrains demonstrated that Bap is expressed at the cell surface and is associated with biofilm formation. Finally, biofilm formation by these Bap-positive strains could be inhibited by affinity-purified Bap antibodies, demonstrating the direct contribution of Bap to biofilm growth byA. baumanniiclinical isolates.


Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1848
Author(s):  
Kyeongmin Kim ◽  
Md Maidul Islam ◽  
Dooyoung Kim ◽  
Sung Ho Yun ◽  
Jungmin Kim ◽  
...  

Acinetobacter baumannii is a nosocomial pathogen, which is a problem worldwide due to the emergence of a difficult-to-treat multidrug-resistant A. baumannii (MDRAB). Endolysins are hydrolytic enzymes produced by a bacteriophage that can be used as a potential therapeutic agent for multidrug-resistant bacterial infection in replacing antibiotics. Here, we isolated a novel bacteriophage through prophage induction using mitomycin C from clinical A. baumannii 1656-2. Morphologically, ΦAb1656-2 was identified as a Siphoviridae family bacteriophage, which can infect MDRAB. The whole genome of ΦAb1656-2 was sequenced, and it showed that it is 50.9 kb with a G + C content of 38.6% and 68 putative open reading frames (ORFs). A novel endolysin named AbEndolysin with an N-acetylmuramidase-containing catalytic domain was identified, expressed, and purified from ΦAb1656-2. Recombinant AbEndolysin showed significant antibacterial activity against MDRAB clinical strains without any outer membrane permeabilizer. These results suggest that AbEndolysin could represent a potential antimicrobial agent for treating MDRAB clinical isolates.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kah Ern Ten ◽  
Muhammad Zarul Hanifah Md Zoqratt ◽  
Qasim Ayub ◽  
Hock Siew Tan

Abstract Objective The nosocomial pathogen, Acinetobacter baumannii, has acquired clinical significance due to its ability to persist in hospital settings and survive antibiotic treatment, which eventually resulted in the rapid spread of this bacterium with antimicrobial resistance (AMR) phenotypes. This study used a multidrug-resistant A. baumannii (strain ATCC BAA1605) as a model to study the genomic features of this pathogen. Results One circular chromosome and one circular plasmid were discovered in the complete genome of A. baumannii ATCC BAA1605 using whole-genome sequencing. The chromosome is 4,039,171 bp long with a GC content of 39.24%. Many AMR genes, which confer resistance to major classes of antibiotics (beta-lactams, aminoglycosides, tetracycline, sulphonamides), were found on the chromosome. Two genomic islands were predicted on the chromosome, one of which (Genomic Island 1) contains a cluster of AMR genes and mobile elements, suggesting the possibility of horizontal gene transfer. A subtype I-F CRISPR-Cas system was also identified on the chromosome of A. baumannii ATCC BAA1605. This study provides valuable genome data that can be used as a reference for future studies on A. baumannii. The genome of A. baumannii ATCC BAA1605 has been deposited at GenBank under accession no. CP058625 and CP058626.


2021 ◽  
Vol 204 (1) ◽  
Author(s):  
Wenyi Peng ◽  
Fei Zeng ◽  
Zhiying Wu ◽  
Zeyuan Jin ◽  
Wanxia Li ◽  
...  

Author(s):  
Ziad M.F. Al-Khozai ◽  
Mohammed N.H. Al-Kaabi

This study was carried out during the period from October 2015 to March 2016. It included the isolation of 42 isolates were identified asAcinetobacterbaumannii. All Isolates showed wide range of resistance to antibiotics. Two types of lytic bacteriophages primarily named Phage 1 and Phage 2 were isolated from sewage water. Phage 1 exhibited broad host spectrum it was lytic against all Acinetobacter baumannii isolates included for the study. Conversely,phage 2 have narrow host range as they could inhibit only 30 isolates,None of these phages inhibited a bacterium other than staphylococci species. The adsorption rate of Phage 1 was 3.1×10-10 ml min-1while Phage 2 was 1.7×10-10 ml min-1. Eclipse and Latent periods of Phage 1 were 6,17 minutes and for phage 2 were 7,14 minutes respectively,the burst size of Phage 1 and Phage 2 were 73±16 pfu\cell and 38±11 pfu\cell respectively. Complete lysis time of Phage 1 particles was 4.30 hours while the complete lysis time of Phage 2 particles was 6 hours. Phages passaging results showed a remarkable increment in PFU which were reached its maximal elevation at six passage in Phage 1 and fourth passage in Phage 2. Fitness of Phage 1 and Phage 2 were 24 ±5 pfu\cell and 26 ±4 pfu\cellrespectively through six generations. The Phage 1 and Phage 2 particles were stabled at a wide range of pH (6-10) and temperatures (30-50°C),the optimal temperature of two phages were 37°C.


2021 ◽  
Author(s):  
Huabo Yu ◽  
Chao Feng ◽  
Liang Zhang ◽  
Teng Chi ◽  
Yanling Qi ◽  
...  

Abstract Aeromonas hydrophila (A.hydrophila) is an opportunistic pathogen of fish-human-livestock, which poses a seriously affects to the development of aquaculture. Phage therapy is considered as a process to alternatively control bacterial infections and contaminations. In this study, the genomes of two Aeromonas hydrophila- specific phages PZL-Ah1 and PZL-Ah8 were isolated, characterized and genomic sequence analyzed. Transmission electron microscopy showed that the two phages had been classified as the member of the Podoviridae family. Both the two phages in this study had relatively narrow host range with lytic activity against Aeromonas spp. strains. However, they could lyse 3 common A.hydrophila strain. As revealed from the whole genomic sequence analysis, PZL-Ah1 and PZL-Ah8 coverd the double-stranded genome of 38,641 bp and 40,855 bp in length, with the GC content of 53.68% and 51.89%, respectively. Through gene comparison in NCBI database revealed that PZL-Ah1 and PZL-Ah8 were 97.67% − 95.51% identical to Stenotrophomonas phage IME15 and Aeromonas Phage T7-Ah. Phylogenetic analysis showed that PZL-Ah8, PZL-Ah1 and other two phages belonged to the same genus. A total of 44 and 52 open reading frames (ORFs) were predicted in the PZL-Ah1 and PZL-Ah8 genome, respectively. In the process of gene annotation, 28 (63.6%) ORFs in PZL-Ah1 and 29 (55.8%) ORFs in PZL-Ah8 were known to functional proteins in NCBI database, while the remaining ORFs were classified as “hypothetical proteins”, whose functions were yet unknown. By comparing, ORF 02, ORF 29 and ORF 04 in PZL-Ah1, ORF24 in PZL-Ah8 were responsible for the host cell lysis. In conclusion, genomic studies of these two novel phages would lay the foundation for expanding the phage genome database and providing good candidates for phage typing applications.


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