High-resolution genotyping of Pseudomonas aeruginosa strains linked to acute post cataract surgery endophthalmitis outbreaks in India.
BACKGROUND
Investigation of two independent outbreaks of post cataract surgery endophthalmitis identified the reservoir of epidemic strains of P. aeruginosa.


METHODS
Patient isolates cultured from vitreous fluid of all the nine cases and from the peripheral devices of phacoemulsification machine were subjected to high-resolution Fluorescent Amplified Fragment Length Polymorphism (FAFLP) analysis.


RESULTS
FAFLP based genotyping of the isolates confirmed nosocomial transmission. Although biochemical characterization and antibiotic susceptibility profiles grouped all the isolates together, FAFLP based genotyping revealed that, all the outbreak isolates were derived from 2 different strains, with independent origins. One group of isolates was traced to phacoprobe and the second one to the internal tubing system of the phacoemulsification machine used in cataract surgery. In silico analysis indicated possible evolution in both the clusters of P. aeruginosa isolates due to genetic polymorphisms. The polymorphisms were mapped to gene products (cell envelope, outer membrane proteins) possibly having significant role in pathogenesis.


CONCLUSIONS
The present study is probably the first one to apply FAFLP typing successfully to investigate outbreaks of postoperative endophthalmitis (POE) in an ophthalmic setting, which was able to identify the source, and helped to make rational decisions on sterilization procedures that halted more cases of infection in these hospitals.
Kenchappa
Prashanth
P
Pathogen Evolution Group, Centre for DNA Fingerprinting and Diagnostics (CDFD), Nacharam, Hyderabad, India. prashant@cdfd.org.in
Sangwan
Virender S
VS
Ahmed
Niyaz
N
Rao
K Rajender
KR
Pathengay
Avinash
A
Mathai
Annie
A
Mansoori
Tarannum
T
Das
Taraprasad
T
Hasnain
Seyed E
SE
Sharma
Savitri
S
D000208:Acute Disease; D001483:Base Sequence; D002386:Cataract / Q000382:microbiology*; D002387:Cataract Extraction / Q000009:adverse effects*; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D017931:DNA Primers; D004196:Disease Outbreaks; D009877:Endophthalmitis / Q000453:epidemiology / Q000382:microbiology*; D005838:Genotype; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D009873:Operating Rooms; D011552:Pseudomonas Infections / Q000453:epidemiology*; D011550:Pseudomonas aeruginosa / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D015183:Restriction Mapping; D014822:Vitreous Body / Q000382:microbiology*
D017931:DNA Primers; D004247:DNA