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Letters to the Editor
Prophylactic intracameral antibiotic use during cataract surgery In a recent article, Kam et al.1 described the frequency of intracameral antibiotic usage following cataract surgery among cataract surgeons in Victoria, Australia. The adoption rate of intracameral antibiotics among surgeons in Victoria are indeed impressive, and the authors reported a corresponding decrease in the rate of endophthalmitis seen at the Royal Victorian Eye and Ear Hospital during the period following the increased adoption of intracameral antibiotics.1 From the authors’ results, intracameral cefazolin was used by 72.9% of respondents, either alone or in combination with subconjunctival cefazolin. In contrast, from the chart in figure 1 of their article, subconjunctival gentamicin (either given in combination with cefazolin or alone) appears to be used by less than 10% of cataract surgeons, with a small number giving only subconjunctival gentamicin. We are curious whether the survey respondents were asked for the rationale behind their choice of antibiotics. In most reports, Gram-positive organisms were the most common causative organisms of postoperative endophthalmitis, and many centres use cephalosporins because of the coverage of Gram-positive organisms (63–70%).2–5 At our centre, both intracameral cefazolin and subconjunctival gentamicin are used at the end of surgery in order to provide prophylaxis against both Gram-positive and Gram-negative organisms. This is relevant because we found that among our patients with endophthalmitis, 25% of culture-positive patients had Gram-negative organisms such as pseudomonas sp.2 The rate of culture of Gram-negative organisms from endophthalmitis reported in some Asian populations is higher than in Caucasian populations (19–25%), and we are curious about the types of organisms cultured from the patients as seen at Royal Victorian Eye and Ear Hospital. If the rates of Gram-negative organisms cultured are relatively high, then the use of an antibiotic, which provides greater coverage of Gram-negative organism such as gentamicin, may be a relevant consideration. In their manuscript, Kam et al. commented on the lack of a treatment arm that utilized prophylactic subconjunctival cefuroxime in the study by the European Society of Cataract and Refractive Surgeons.3 In view of the weight of current evidence for the efficacy of intracameral antibiotics, it is unlikely that such a comparison will be performed in a future randomized controlled trial. The authors mentioned non-randomized studies demonstrating a decrease in the rate of endophthalmitis following the use of intracameral cefuroxime. We would like to highlight that similar trends were observed when cefazolin was used. In a review of 50 177 cases of cataract surgery, the rates of Competing/conflicts of interest: No stated conflict of interest. Funding sources: Dr Tan receives grant funding from the National
495 endophthalmitis was 0.064% when subconjunctival cefazolin was used, and decreased significantly to 0.01% following a switch to intracameral cefazolin (multivariate odds ratio 13.6, P < 0.0001).2 Like the authors, we also recognize that this study compared two cohorts over different time periods, and the results may have been influenced by other factors such as improvements in surgical technique or equipment. However, in the absence of level 1 evidence from a randomized controlled trial, we feel that these findings are important for ophthalmologists to consider when assessing the utility of prophylactic antibiotics. In summary, we fully agree with the authors that it is essential for evidence of the efficacy of prophylactic intracameral antibiotics in reducing the rates of endophthalmitis to be disseminated to cataract surgeons, and applaud their important contributions to this effort.
Colin SH Tan FRCSEd(Ophth),1,2 Milton C Chew MBBS1 and Louis W Lim MBBS1 1 Tan Tock Seng Hospital and 2Fundus Image Reading Center, National Healthcare Group Eye Institute, Singapore Received 20 October 2014; accepted 26 October 2014.
REFERENCES 1. Kam JK, Buck D, Dawkins R, Sandhu SS, Allen PJ. Survey of prophylactic intracameral antibiotic use in cataract surgery in an Australian context. Clin Experiment Ophthalmol 2014; 42: 398–400. 2. Tan CSH, Wong HK, Yang FP. Epidemiology of postoperative endophthalmitis in an Asian population: 11-year incidence and effect of intracameral antibiotic agents. J Cataract Refract Surg 2012; 38: 425–30. 3. Barry P, Gardner S, Seal D et al. Clinical observations associated with proven and unproven cases in the ESCRS study of prophylaxis of postoperative endophthalmitis after cataract surgery. J Cataract Refract Surg 2009; 35: 1523–31, 1531.e1. 4. Garat M, Moser CL, Martín-Baranera M, Alonso-Tarrés C, Alvarez-Rubio L. Prophylactic intracameral cefazolin after cataract surgery: endophthalmitis risk reduction and safety results in a 6-year study. J Cataract Refract Surg 2009; 35: 637–42. 5. Romero P, Méndez I, Salvat M, Fernández J, Almena M. Intracameral cefazolin as prophylaxis against endophthalmitis in cataract surgery. J Cataract Refract Surg 2006; 32: 438–41.
Prophylactic intracameral antibiotic use during cataract surgery: response We thank Tan et al.1 for taking the time to comment on our letter.2 In answer to their question, survey respondents were not asked for the rationale behind their choice of
Healthcare Group Clinician Scientist Career Scheme Grant CSCS/ 12005, and travel support from Bayer, Heidelberg Engineering
Conflict of interest: No stated conflict of interest.
and Novartis.
Funding sources: No stated funding sources.
© 2014 Royal Australian and New Zealand College of Ophthalmologists
496
Letters to the Editor
antibiotics. We have, however, recently looked into the microbial spectrum of cases of endophthalmitis presenting to us at The Royal Victorian Eye and Ear Hospital (RVEEH, East Melbourne, Victoria, Australia) for the time period July 1997–June 2011.3 Of 280 culture-positive postcataract surgery endophthalmitis cases, 254 (90.7%) grew Gram-positive bacterial species, 22 (7.9%) grew Gramnegative bacterial species and 4 (1.4%) were fungal (Table 1). More specifically, there were only 12 (4.3%) cases that grew Pseudomonas aeruginosa on culture. The Gram-negative species grown is a third of those reported by Tan et al. and may be the reason that subconjunctival gentamicin is less often used among surgeons in our region. Subconjunctival gentamicin may indeed have a role in our setting, but as the authors point out, the microbiological spectrum is different from that in reported series from Asia. For this reason, it would be interesting to know if Tan et al. have noted a measurable reduction in Gram-negative bacterial endophthalmitis with their broad spectrum antibiotic regime, and if there have been any adverse events. Aminoglycoside toxicity can be a concern, especially in the setting of inadvertent intraocular injection of drug that was meant for subconjunctival injection.4,5 For reader interest, we also present the commonest organisms of the culture-positive endophthalmitis cases seen at RVEEH between July 1997 and June 2011, categorized by precipitating event (Table 2).
Table 1. RVEEH culture-positive microbial spectrum endophthalmitis cases between July 1997 and June 2011
Cataract surgery Glaucoma surgery Penetrating eye injury Corneal ulceration Vitreoretinal surgery Intravitreal injection Endogenous
of
Number of cases
Grampositive
Gramnegative
Fungal
280 51 37 35 13 20 59
90.7% 64.7% 83.8% 54.3% 92.3% 100.00% 18.6%
7.9% 35.3% 8.1% 40.0% 7.7% 0.0% 16.9%
1.4% 0.0% 8.1% 5.7% 0.0% 0.0% 64.4%
Jonathan K Kam MBBS(Hons) BMedSc(Hons),1 Danielle Buck MBBS,1 Rosie Dawkins MBBS MPH,1 Sukhpal S Sandhu MD FRANZCO1,2 and Penelope J Allen FRANZCO1,2 1 Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, and 2Department of Ophthalmology, Centre for Eye Research Australia, Melbourne, Victoria, Australia Received 4 November 2014; accepted 4 November 2014.
REFERENCES 1. Tan CSH, Chew MC, Lim LW. Prophylactic intracameral antibiotic use during cataract surgery. Clin Experiment Ophthalmol 2015; 43: 495. 2. Kam JK, Buck D, Dawkins R, Sandhu SS, Allen PJ. Survey of prophylactic intracameral antibiotic use in cataract surgery in an Australian context. Clin Experiment Ophthalmol 2014; 42: 398–400. 3. Kam JK, Dawkins R, Buck D, Sandhu S, Allen P. Changing patterns of endophthalmitis at a state-wide service in Australia over a 14 year period. Invest Ophthalmol Vis Sci 2013; 54. E-Abstract 3174. 4. Ha BJ, Lee SH, Kim YM, Kwon HS, Chu YK, Seo KY. A case of inadvertent anterior chamber and corneal stromal injection with antibiotics during cataract operation. Korean J Ophthalmol 2006 Dec; 20: 241–5. 5. McDonald HR, Schatz H, Allen AW et al. Retinal toxicity secondary to intraocular gentamicin injection. Ophthalmology 1986 Jul; 93: 871–7.
RVEEH, Royal Victorian Eye and Ear Hospital. Table 2. RVEEH commonest organisms between July 1997 and June 2011 Cataract surgery
Glaucoma surgery
Penetrating eye injury
Corneal ulceration
Vitreoretinal surgery
Intravitreal injection
Endogenous
Coagulase 43.6% Streptococcus 43.1% Coagulase 35.1% Pseudomonas 28.6% Coagulase 53.8% Coagulase 50.0% Fungi 64.4% negative sp. negative aeruginosa negative negative Staphylococcus Staphylococcus Staphylococcus Staphylococcus Streptococcus sp. 19.6% Moraxella sp. 21.6% Streptococcus sp. 13.5% Streptococcus 25.7% Streptococcus sp. 25.0% Klebsiella 8.5% sp. pneumonia Staphylococcus 16.8% Haemophilus 9.8% Bacillus sp. 13.5% Coagulase 11.4% Coagulase 8.5% aureus influenzae negative negative Staphylococcus Staphylococcus Propionibacterium 8.1% acnes Fungi 8.1%
RVEEH, Royal Victorian Eye and Ear Hospital.
© 2014 Royal Australian and New Zealand College of Ophthalmologists
Letters to the Editor
Prophylactic intracameral antibiotic use during cataract surgery In a recent article, Kam et al.1 described the frequency of intracameral antibiotic usage following cataract surgery among cataract surgeons in Victoria, Australia. The adoption rate of intracameral antibiotics among surgeons in Victoria are indeed impressive, and the authors reported a corresponding decrease in the rate of endophthalmitis seen at the Royal Victorian Eye and Ear Hospital during the period following the increased adoption of intracameral antibiotics.1 From the authors’ results, intracameral cefazolin was used by 72.9% of respondents, either alone or in combination with subconjunctival cefazolin. In contrast, from the chart in figure 1 of their article, subconjunctival gentamicin (either given in combination with cefazolin or alone) appears to be used by less than 10% of cataract surgeons, with a small number giving only subconjunctival gentamicin. We are curious whether the survey respondents were asked for the rationale behind their choice of antibiotics. In most reports, Gram-positive organisms were the most common causative organisms of postoperative endophthalmitis, and many centres use cephalosporins because of the coverage of Gram-positive organisms (63–70%).2–5 At our centre, both intracameral cefazolin and subconjunctival gentamicin are used at the end of surgery in order to provide prophylaxis against both Gram-positive and Gram-negative organisms. This is relevant because we found that among our patients with endophthalmitis, 25% of culture-positive patients had Gram-negative organisms such as pseudomonas sp.2 The rate of culture of Gram-negative organisms from endophthalmitis reported in some Asian populations is higher than in Caucasian populations (19–25%), and we are curious about the types of organisms cultured from the patients as seen at Royal Victorian Eye and Ear Hospital. If the rates of Gram-negative organisms cultured are relatively high, then the use of an antibiotic, which provides greater coverage of Gram-negative organism such as gentamicin, may be a relevant consideration. In their manuscript, Kam et al. commented on the lack of a treatment arm that utilized prophylactic subconjunctival cefuroxime in the study by the European Society of Cataract and Refractive Surgeons.3 In view of the weight of current evidence for the efficacy of intracameral antibiotics, it is unlikely that such a comparison will be performed in a future randomized controlled trial. The authors mentioned non-randomized studies demonstrating a decrease in the rate of endophthalmitis following the use of intracameral cefuroxime. We would like to highlight that similar trends were observed when cefazolin was used. In a review of 50 177 cases of cataract surgery, the rates of Competing/conflicts of interest: No stated conflict of interest. Funding sources: Dr Tan receives grant funding from the National
495 endophthalmitis was 0.064% when subconjunctival cefazolin was used, and decreased significantly to 0.01% following a switch to intracameral cefazolin (multivariate odds ratio 13.6, P < 0.0001).2 Like the authors, we also recognize that this study compared two cohorts over different time periods, and the results may have been influenced by other factors such as improvements in surgical technique or equipment. However, in the absence of level 1 evidence from a randomized controlled trial, we feel that these findings are important for ophthalmologists to consider when assessing the utility of prophylactic antibiotics. In summary, we fully agree with the authors that it is essential for evidence of the efficacy of prophylactic intracameral antibiotics in reducing the rates of endophthalmitis to be disseminated to cataract surgeons, and applaud their important contributions to this effort.
Colin SH Tan FRCSEd(Ophth),1,2 Milton C Chew MBBS1 and Louis W Lim MBBS1 1 Tan Tock Seng Hospital and 2Fundus Image Reading Center, National Healthcare Group Eye Institute, Singapore Received 20 October 2014; accepted 26 October 2014.
REFERENCES 1. Kam JK, Buck D, Dawkins R, Sandhu SS, Allen PJ. Survey of prophylactic intracameral antibiotic use in cataract surgery in an Australian context. Clin Experiment Ophthalmol 2014; 42: 398–400. 2. Tan CSH, Wong HK, Yang FP. Epidemiology of postoperative endophthalmitis in an Asian population: 11-year incidence and effect of intracameral antibiotic agents. J Cataract Refract Surg 2012; 38: 425–30. 3. Barry P, Gardner S, Seal D et al. Clinical observations associated with proven and unproven cases in the ESCRS study of prophylaxis of postoperative endophthalmitis after cataract surgery. J Cataract Refract Surg 2009; 35: 1523–31, 1531.e1. 4. Garat M, Moser CL, Martín-Baranera M, Alonso-Tarrés C, Alvarez-Rubio L. Prophylactic intracameral cefazolin after cataract surgery: endophthalmitis risk reduction and safety results in a 6-year study. J Cataract Refract Surg 2009; 35: 637–42. 5. Romero P, Méndez I, Salvat M, Fernández J, Almena M. Intracameral cefazolin as prophylaxis against endophthalmitis in cataract surgery. J Cataract Refract Surg 2006; 32: 438–41.
Prophylactic intracameral antibiotic use during cataract surgery: response We thank Tan et al.1 for taking the time to comment on our letter.2 In answer to their question, survey respondents were not asked for the rationale behind their choice of
Healthcare Group Clinician Scientist Career Scheme Grant CSCS/ 12005, and travel support from Bayer, Heidelberg Engineering
Conflict of interest: No stated conflict of interest.
and Novartis.
Funding sources: No stated funding sources.
© 2014 Royal Australian and New Zealand College of Ophthalmologists
496
Letters to the Editor
antibiotics. We have, however, recently looked into the microbial spectrum of cases of endophthalmitis presenting to us at The Royal Victorian Eye and Ear Hospital (RVEEH, East Melbourne, Victoria, Australia) for the time period July 1997–June 2011.3 Of 280 culture-positive postcataract surgery endophthalmitis cases, 254 (90.7%) grew Gram-positive bacterial species, 22 (7.9%) grew Gramnegative bacterial species and 4 (1.4%) were fungal (Table 1). More specifically, there were only 12 (4.3%) cases that grew Pseudomonas aeruginosa on culture. The Gram-negative species grown is a third of those reported by Tan et al. and may be the reason that subconjunctival gentamicin is less often used among surgeons in our region. Subconjunctival gentamicin may indeed have a role in our setting, but as the authors point out, the microbiological spectrum is different from that in reported series from Asia. For this reason, it would be interesting to know if Tan et al. have noted a measurable reduction in Gram-negative bacterial endophthalmitis with their broad spectrum antibiotic regime, and if there have been any adverse events. Aminoglycoside toxicity can be a concern, especially in the setting of inadvertent intraocular injection of drug that was meant for subconjunctival injection.4,5 For reader interest, we also present the commonest organisms of the culture-positive endophthalmitis cases seen at RVEEH between July 1997 and June 2011, categorized by precipitating event (Table 2).
Table 1. RVEEH culture-positive microbial spectrum endophthalmitis cases between July 1997 and June 2011
Cataract surgery Glaucoma surgery Penetrating eye injury Corneal ulceration Vitreoretinal surgery Intravitreal injection Endogenous
of
Number of cases
Grampositive
Gramnegative
Fungal
280 51 37 35 13 20 59
90.7% 64.7% 83.8% 54.3% 92.3% 100.00% 18.6%
7.9% 35.3% 8.1% 40.0% 7.7% 0.0% 16.9%
1.4% 0.0% 8.1% 5.7% 0.0% 0.0% 64.4%
Jonathan K Kam MBBS(Hons) BMedSc(Hons),1 Danielle Buck MBBS,1 Rosie Dawkins MBBS MPH,1 Sukhpal S Sandhu MD FRANZCO1,2 and Penelope J Allen FRANZCO1,2 1 Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, and 2Department of Ophthalmology, Centre for Eye Research Australia, Melbourne, Victoria, Australia Received 4 November 2014; accepted 4 November 2014.
REFERENCES 1. Tan CSH, Chew MC, Lim LW. Prophylactic intracameral antibiotic use during cataract surgery. Clin Experiment Ophthalmol 2015; 43: 495. 2. Kam JK, Buck D, Dawkins R, Sandhu SS, Allen PJ. Survey of prophylactic intracameral antibiotic use in cataract surgery in an Australian context. Clin Experiment Ophthalmol 2014; 42: 398–400. 3. Kam JK, Dawkins R, Buck D, Sandhu S, Allen P. Changing patterns of endophthalmitis at a state-wide service in Australia over a 14 year period. Invest Ophthalmol Vis Sci 2013; 54. E-Abstract 3174. 4. Ha BJ, Lee SH, Kim YM, Kwon HS, Chu YK, Seo KY. A case of inadvertent anterior chamber and corneal stromal injection with antibiotics during cataract operation. Korean J Ophthalmol 2006 Dec; 20: 241–5. 5. McDonald HR, Schatz H, Allen AW et al. Retinal toxicity secondary to intraocular gentamicin injection. Ophthalmology 1986 Jul; 93: 871–7.
RVEEH, Royal Victorian Eye and Ear Hospital. Table 2. RVEEH commonest organisms between July 1997 and June 2011 Cataract surgery
Glaucoma surgery
Penetrating eye injury
Corneal ulceration
Vitreoretinal surgery
Intravitreal injection
Endogenous
Coagulase 43.6% Streptococcus 43.1% Coagulase 35.1% Pseudomonas 28.6% Coagulase 53.8% Coagulase 50.0% Fungi 64.4% negative sp. negative aeruginosa negative negative Staphylococcus Staphylococcus Staphylococcus Staphylococcus Streptococcus sp. 19.6% Moraxella sp. 21.6% Streptococcus sp. 13.5% Streptococcus 25.7% Streptococcus sp. 25.0% Klebsiella 8.5% sp. pneumonia Staphylococcus 16.8% Haemophilus 9.8% Bacillus sp. 13.5% Coagulase 11.4% Coagulase 8.5% aureus influenzae negative negative Staphylococcus Staphylococcus Propionibacterium 8.1% acnes Fungi 8.1%
RVEEH, Royal Victorian Eye and Ear Hospital.
© 2014 Royal Australian and New Zealand College of Ophthalmologists
