agar and Endophthalmitis

We describe the microbiological profile of postoperative endophthalmitis from northern India and analyse the pattern of antibiotic sensitivity which may have changed due to development of resistance secondary to overuse of antimicrobial drugs.. This is a retrospective study of postoperative endophthalmitis from January 2011 to December 2017 in a tertiary eye hospital of northern India. Any patient developing endophthalmitis within one year of any intraocular procedure was included in the study. According to severity, treatment with a trial of intravitreal antibiotic injections or core vitrectomy was decided. Ocular samples were collected which were either anterior chamber tap or vitreous biopsy and sent for microbiological examination. The samples were stained with Gram's and KOH stain and cultured on chocolate agar, blood agar, brain heart infusion broth and Sabouraud dextrose agar.. A total of 545 patients of postoperative endophthalmitis were analysed which showed a male predilection (60.5%) with maximum patients between the age group 50-69 years. 292 patients (53.5%) were culture negative and 253 patients (46.4%) were culture positive. Most common organism identified was Staphylococcus in 73 patients followed by Pseudomonas in 48 patients. Staphylococcus species was most sensitive to vancomycin (97%) followed by amikacin (91%) followed by gentamicin and moxifloxacin (88% each). Pseudomonas was the second most common isolate which showed maximum sensitivity to imipenem (82%) followed by ciprofloxacin(60%). Polymicrobial infection was noted in 23 patients. The most common fungal isolate was aspergillus in 11 patients, followed by fusarium in 10 patients.. Our study shows that gram positive bacteria are the most common organisms in postoperative endophthalmitis and are most sensitive to vancomycin, followed by gram negative bacteria which show increased sensitivity with imipenem than commonly used antibiotic - ceftazidime.

Topics: Agar; Aged; Anti-Bacterial Agents; Endophthalmitis; Eye Infections, Bacterial; Humans; Imipenem; Male; Microbial Sensitivity Tests; Middle Aged; Postoperative Complications; Retrospective Studies; Tertiary Care Centers; Vancomycin; Vitrectomy

Prospective laboratory methodology study.. Certain tissues, by virtue of their shape and extreme thinness or pliability, are difficult to position correctly during routine paraffin embedding to provide the optimal orientation for histopathologic studies. Biopsy specimens from temporal arteries must be sampled at different points along the length of the artery. Other tissues such as subfoveal neovascular membranes and fragments of lens capsule lack the thickness and rigidity to be positioned on edge to yield cross-sectional views. The authors' technique improves the orientation and thereby maximizes the histologic information obtained from such specimens.. From January 1, 1990, to April 30, 1999, the authors studied 500 consecutive temporal artery biopsy specimens and 200 successive subfoveal neovascular membranes.. Cutting a 20-mm cylindrical fragment of temporal artery at 1- to 1.5-mm intervals yielded approximately 13 to 20 cross-sections along the length of the artery. When the specimens were positioned together and embedded in agar, the pathologist could easily study multiple cross-sections of the artery. Additionally, using the agar technique, the authors were able to obtain cross-sections of other specimens submitted, such as subfoveal neovascular membranes, and studied each of the different layers to evaluate the disease process. By the same method, the authors placed small fragments of lens capsule with underlying cortex on edge and readily identified short, gram-positive coccobacilli consistent with Propionibacterium acnes endophthalmitis.. The agar technique can greatly improve the quality of diagnostic information gleaned from temporal artery biopsy specimens and other small tissue samples.

Topics: Agar; Biopsy; Endophthalmitis; Epiretinal Membrane; Eye Infections, Bacterial; Giant Cell Arteritis; Gram-Positive Bacterial Infections; Humans; Lens Capsule, Crystalline; Ophthalmology; Pathology, Surgical; Propionibacterium acnes; Prospective Studies; Specimen Handling; Temporal Arteries

Propionibacterium acnes has been identified as a significant agent of nosocomial infections, including endophthalmitis. Data concerning susceptibility of P. acnes to newer beta-lactam antibiotics and fluoroquinolones are limited. Recent reports suggest that quinolones have activity against these organisms sufficient to warrant further study. We undertook a study to select appropriate antimicrobial agents for use in a rabbit model of P. acnes endophthalmitis. We compared the antibiotic susceptibilities of P. acnes by using the National Committee for Clinical Laboratory Standards method of agar dilution with the E test. Thirteen clinical isolates obtained from eye specimens and three American Type Culture Collection control strains were tested against 14 antibiotics. All the clinical isolates were susceptible by both methods to piperacillin, piperacillin-tazobactam, ampicillin-sulbactam, ticarcillin-clavulanate, cefotaxime, cefotetan, ceftriaxone, cefoxitin, and imipenem in addition to clindamycin but were resistant to metronidazole. The clinical P. acnes isolates also displayed high-level susceptibility to ciprofloxacin, sparfloxacin, and ofloxacin. Almost all the P. acnes strains demonstrated E-test MICs within 2 dilutions of the MICs observed by the agar dilution method. Those few strains for which discrepancies were noted exhibited E-test susceptibilities three- to fivefold dilutions lower than the agar dilution method susceptibilities but only with ampicillin-sulbactam, ticarcillin-clavulanate, and/or clindamycin. On the basis of our study, all of clinical eye isolates were susceptible to these newer antimicrobial agents and the two methods demonstrated similar susceptibility patterns.

Topics: Agar; Animals; Anti-Bacterial Agents; Anti-Infective Agents; Cross Infection; Disease Models, Animal; Endophthalmitis; Fluoroquinolones; Gram-Positive Bacterial Infections; Humans; Lactams; Microbial Sensitivity Tests; Propionibacterium acnes; Rabbits