Polymerase chain reaction in the diagnosis of Aspergillus endophthalmitis.

BACKGROUND & OBJECTIVES: Aspergillus endophthalmitis is the commonest type of vision threatening fungal endophthalmitis encountered in India. Since conventional methods lack sensitivity, we evaluated polymerase chain reaction (PCR) against the conventional mycological methods in the diagnosis of Aspergillus endophthalmitis. METHODS: Twenty-seven intraocular specimens from 22 patients with suspected fungal endophthalmitis (proven as non-bacterial origin) and 10 patients with non-infective intraocular disorders (controls) were tested. The intraocular specimens from these patients were subjected to the conventional methods, viz., microscopy and culture for growth of fungi, as well as PCR for the detection and differentiation of species of Aspergillus. RESULTS: None of the controls were positive by microscopy, culture or PCR. Among the 27 test samples, 4 were positive by culture for Aspergillus species, these were also positive by PCR. In addition, PCR detected and identified Aspergillus species in 2 culture negative specimens. The average time required for culture and identification of Aspergillus was 10 days, whereas PCR needed only 24 h. INTERPRETATION & CONCLUSION: This study indicates that PCR was not only a more sensitive, but also a rapid diagnostic tool compared to the conventional mycological methods in the diagnosis of Aspergillus endophthalmitis.

Spectrum of aetiological agents of postoperative endophthalmitis and antibiotic susceptibility of bacterial isolates.

PURPOSE: To determine the spectrum of infectious agents of postoperative endophthalmitis, the relationship with the time of onset of symptoms after surgery and the antibiotic susceptibilities of the aerobic bacterial isolates. METHODS: A retrospective review of microbiological records from January 1995 to December 1998 yielded 173 isolates from intraocular specimen of 170 patients with culture-proven postoperative endophthalmitis. Antibiotic susceptibility of these isolates was determined for various ocular antibiotics using the Kirby-Bauer disk-diffusion test. Based on the time of onset of illness, clinical presentation was classified into acute, delayed and chronic. RESULTS: Among 170 cases, 71 (41.7%) were attributable to gram-negative, 64 (37.6%) to gram-positive bacteria, and 37 (21.8%) to fungi. Gram-negative bacteria included P. aeruginosa (29;17.1%), other Pseudomonas spp (15;8.8%), non-fermenters (18;10.6%) and others (10;5.8%). Among these, 40 of 72 (55.5%) were sensitive to gentamicin, 47 of 72 (65.2%) to cefotaxime, 47 of 69 (68.1%) to amikacin, 52 of 71 (73.2%) to ciprofloxacin, and 25 of 40 (62.5%) to ceftazidime. The gram-positive bacteria included S. epidermidis (22;12.9%), S. aureus (13;7.6%), P. acnes (10;5.9%), Enterococcus spp (4;2.3%), Streptococcus spp (7;4.1%) and others (8;4.8%). Among these, 41 of 53 (77.3%) were sensitive to gentamicin, 47 of 53 (88.6%) to cefotaxime, 46 of 52 (88.4%) to ciprofloxacin, 38 of 41 (92.6%) to cefazolin and 27 of 37 (72.9%) to ceftazidime. All gram-positive bacteria were sensitive to vancomycin. CONCLUSION: In this large series of postoperative endophthalmitis, gram-negative bacilli followed by fungi accounted for the largest number of cases. A high degree of resistance of gram-negative bacilli to gentamicin, cefotaxime, amikacin and ceftazidime was recorded.