PMID- 38166139
OWN - NLM
STAT- MEDLINE
DCOM- 20240122
LR  - 20240201
IS  - 1935-2735 (Electronic)
IS  - 1935-2727 (Print)
IS  - 1935-2727 (Linking)
VI  - 18
IP  - 1
DP  - 2024 Jan
TI  - The role of naturally acquired intracellular Pseudomonas aeruginosa in the 
      development of Acanthamoeba keratitis in an animal model.
PG  - e0011878
LID - 10.1371/journal.pntd.0011878 [doi]
LID - e0011878
AB  - BACKGROUND: Acanthamoeba is an environmental host for various microorganisms. 
      Acanthamoeba is also becoming an increasingly important pathogen as a cause of 
      keratitis. In Acanthamoeba keratitis (AK), coinfections involving pathogenic 
      bacteria have been reported, potentially attributed to the carriage of microbes 
      by Acanthamoeba. This study assessed the presence of intracellular bacteria in 
      Acanthamoeba species recovered from domestic tap water and corneas of two 
      different AK patients and examined the impact of naturally occurring 
      intracellular bacteria within Acanthamoeba on the severity of corneal infections 
      in rats. METHODOLOGY/PRINCIPAL FINDINGS: Household water and corneal swabs were 
      collected from AK patients. Acanthamoeba strains and genotypes were confirmed by 
      sequencing. Acanthamoeba isolates were assessed for the presence of intracellular 
      bacteria using sequencing, fluorescence in situ hybridization (FISH), and 
      electron microscopy. The viability of the bacteria in Acanthamoeba was assessed 
      by labelling with alkyne-functionalized D-alanine (alkDala). Primary human 
      macrophages were used to compare the intracellular survival and replication of 
      the endosymbiotic Pseudomonas aeruginosa and a wild type strain. Eyes of rats 
      were challenged intrastromally with Acanthamoeba containing or devoid of P. 
      aeruginosa and evaluated for the clinical response. Domestic water and corneal 
      swabs were positive for Acanthamoeba. Both strains belonged to genotype T4F. One 
      of the Acanthamoeba isolates harboured P. aeruginosa which was seen throughout 
      the Acanthamoeba's cytoplasm. It was metabolically active and could be seen 
      undergoing binary fission. This motile strain was able to replicate in macrophage 
      to a greater degree than strain PAO1 (p<0.05). Inoculation of Acanthamoeba 
      containing the intracellular P. aeruginosa in rats eyes resulted in a severe 
      keratitis with increased neutrophil response. Acanthamoeba alone induced milder 
      keratitis. CONCLUSIONS/SIGNIFICANCE: Our findings indicate the presence of live 
      intracellular bacteria in Acanthamoeba can increase the severity of acute 
      keratitis in vivo. As P. aeruginosa is a common cause of keratitis, this may 
      indicate the potential for these intracellular bacteria in Acanthamoeba to lead 
      to severe polymicrobial keratitis.
CI  - Copyright: (c) 2024 Rayamajhee et al. This is an open access article distributed 
      under the terms of the Creative Commons Attribution License, which permits 
      unrestricted use, distribution, and reproduction in any medium, provided the 
      original author and source are credited.
FAU - Rayamajhee, Binod
AU  - Rayamajhee B
AUID- ORCID: 0000-0003-3007-8901
AD  - School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, 
      Sydney, Australia.
FAU - Willcox, Mark
AU  - Willcox M
AD  - School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, 
      Sydney, Australia.
FAU - Henriquez, Fiona L
AU  - Henriquez FL
AD  - School of Health and Life Sciences, University of the West of Scotland, Blantyre, 
      Scotland, United Kingdom.
FAU - Vijay, Ajay Kumar
AU  - Vijay AK
AD  - School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, 
      Sydney, Australia.
FAU - Petsoglou, Constantinos
AU  - Petsoglou C
AD  - Sydney and Sydney Eye Hospital, Southeastern Sydney Local Health District, 
      Sydney, Australia.
AD  - Save Sight Institute, University of Sydney, Sydney, Australia.
FAU - Shrestha, Gauri Shankar
AU  - Shrestha GS
AD  - School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, 
      Sydney, Australia.
FAU - Peguda, Hari Kumar
AU  - Peguda HK
AD  - School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, 
      Sydney, Australia.
FAU - Carnt, Nicole
AU  - Carnt N
AD  - School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, 
      Sydney, Australia.
LA  - eng
PT  - Journal Article
DEP - 20240102
PL  - United States
TA  - PLoS Negl Trop Dis
JT  - PLoS neglected tropical diseases
JID - 101291488
RN  - 059QF0KO0R (Water)
SB  - IM
MH  - Humans
MH  - Rats
MH  - Animals
MH  - *Acanthamoeba Keratitis/microbiology/pathology
MH  - Pseudomonas aeruginosa/genetics
MH  - In Situ Hybridization, Fluorescence
MH  - *Acanthamoeba/genetics
MH  - Bacteria/genetics
MH  - Models, Animal
MH  - Water
PMC - PMC10795995
COIS- The authors have declared that no competing interests exist.
EDAT- 2024/01/03 09:42
MHDA- 2024/01/22 06:42
PMCR- 2024/01/02
CRDT- 2024/01/02 14:22
PHST- 2023/09/27 00:00 [received]
PHST- 2023/12/21 00:00 [accepted]
PHST- 2024/01/18 00:00 [revised]
PHST- 2024/01/22 06:42 [medline]
PHST- 2024/01/03 09:42 [pubmed]
PHST- 2024/01/02 14:22 [entrez]
PHST- 2024/01/02 00:00 [pmc-release]
AID - PNTD-D-23-01218 [pii]
AID - 10.1371/journal.pntd.0011878 [doi]
PST - epublish
SO  - PLoS Negl Trop Dis. 2024 Jan 2;18(1):e0011878. doi: 10.1371/journal.pntd.0011878. 
      eCollection 2024 Jan.