Eubacterial PCR for bacterial detection and identification in 100 acute postcataract surgery endophthalmitis.
OBJECTIVE
To evaluate eubacterial PCR compared with conventional cultures for detection and identification of bacterial agents in ocular samples from patients with acute postcataract endophthalmitis.


METHODS
Broad-range eubacterial PCR amplification was used, followed by direct DNA sequencing in ocular samples (aqueous humor, vitreous samples from tap or vitrectomy) from 100 consecutive patients presenting with acute postcataract endophthalmitis. Bacterial cultures were performed on the same ocular samples by using traditional methods (brain-heart infusion broth).


RESULTS
At the time of admission, the detection rate was not significantly different between cultures and PCR (38.2% for cultures versus 34.6% for PCR in aqueous humor samples; 54% versus 57% in vitreous from a vitreous tap). In contrast, in the vitreous obtained from vitrectomy, after intravitreous injection of antibiotics, PCR detected bacteria in 70% of the cases, compared with 9% in cultures. By combining PCR and cultures, bacterial identification was obtained in 47% of aqueous humor samples at admission, in 68% of vitreous samples from a vitreous tap at admission, and in 72% of vitreous samples from pars plana vitrectomy. Gram-positive bacteria predominated (94.3%). The concordance between cultures and PCR was 100%. The contamination rate was 2%.


CONCLUSIONS
Cultures and eubacterial PCR are complementary techniques for bacterial identification in eyes with acute postcataract endophthalmitis. PCR technique was needed for identification of the involved microbial pathogen in 25% of all the cases. Eubacterial PCR is more effective than cultures in detecting bacteria in vitreous samples from patients with previous intravitreous administration of antibiotics.
Chiquet
Christophe
C
Department of Ophthalmology, University Hospital Center (CHU) de Grenoble, Université Joseph Fourier, Grenoble, France. cchiquet@chu-grenoble.fr
Cornut
Pierre-Loic
PL
Benito
Yvonne
Y
Thuret
Gilles
G
Maurin
Max
M
Lafontaine
Pierre-Olivier
PO
Pechinot
Andre
A
Palombi
Karine
K
Lina
Gerard
G
Bron
Alain
A
Denis
Philippe
P
Carricajo
Anne
A
Creuzot
Catherine
C
Romanet
Jean-Paul
JP
Vandenesch
Francois
F
D000208:Acute Disease; D000368:Aged; D001082:Aqueous Humor / Q000382:microbiology; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification*; D001431:Bacteriological Techniques; D004269:DNA, Bacterial / Q000032:analysis*; D009877:Endophthalmitis / Q000382:microbiology*; D015818:Eye Infections, Bacterial / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D018918:Phacoemulsification; D016133:Polymerase Chain Reaction / Q000379:methods*; D011183:Postoperative Complications; D011446:Prospective Studies; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D014822:Vitreous Body / Q000382:microbiology
D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S