The effect of prophylactic topical antibiotics on bacterial resistance patterns in endophthalmitis following intravitreal injection.
OBJECTIVE
The purpose of this study was to evaluate the effect of prophylactic topical antibiotics on bacterial resistance patterns in endophthalmitis following intravitreal injection of anti-vascular endothelial growth factor (VEGF) medications.


METHODS
In this retrospective case-control study, billing records and an infection log were used to identify all cases of endophthalmitis following intravitreal injection of ranibizumab, bevacizumab, or aflibercept between January 1, 2009 and September 30, 2013 at a single retina practice. A 28-month period when topical antibiotic drops were prescribed for use four times a day for 4 days following intravitreal injection was compared to a 21-month period when topical antibiotics were not prescribed. Patients treated during an 8-month transition period were excluded as prescription practices were changed.


RESULTS
During the study period, a total of 172,096 anti-VEGF injections were performed. During the period when antibiotics were prescribed, 28 cases of suspected infectious endophthalmitis occurred from a total of 57,654 injections, ten of which were culture-positive. During the period when antibiotics were not used, 24 cases of suspected endophthalmitis occurred from a total of 89,825 injections, six of which were culture-positive. During the antibiotic period, four of the ten (40 %) culture-positive cases grew bacteria resistant to the prescribed prophylactic antibiotics. In contrast, none of the six culture-positive cases grew bacteria resistant to those antibiotics during the period when antibiotics were not used (odds ratio = 9.0; 95 % confidence interval = 0.40-203.3; p = 0.17).


CONCLUSIONS
The use of prophylactic topical antibiotics following intravitreal injection may lead to higher rates of antibiotic-resistant bacteria in culture-positive endophthalmitis cases.
Mid Atlantic Retina, The Retina Service of Wills Eye Hospital, Thomas Jefferson University, 840 Walnut Street, Suite 1020, Philadelphia, PA, 19107, USA. Storey.p@gmail.com.|USC Eye Institute, University of Southern California, Los Angeles, CA, USA. Storey.p@gmail.com.
Philip
http://orcid.org/0000-0003-2137-7387
P
Storey
Mid Atlantic Retina, The Retina Service of Wills Eye Hospital, Thomas Jefferson University, 840 Walnut Street, Suite 1020, Philadelphia, PA, 19107, USA.
Michael
M
Dollin
Mid Atlantic Retina, The Retina Service of Wills Eye Hospital, Thomas Jefferson University, 840 Walnut Street, Suite 1020, Philadelphia, PA, 19107, USA.
Nadim
N
Rayess
Mid Atlantic Retina, The Retina Service of Wills Eye Hospital, Thomas Jefferson University, 840 Walnut Street, Suite 1020, Philadelphia, PA, 19107, USA.
John
J
Pitcher
Thomas Jefferson University, Philadelphia, PA, USA.
Sahitya
S
Reddy
Mid Atlantic Retina, The Retina Service of Wills Eye Hospital, Thomas Jefferson University, 840 Walnut Street, Suite 1020, Philadelphia, PA, 19107, USA.
James
J
Vander
Mid Atlantic Retina, The Retina Service of Wills Eye Hospital, Thomas Jefferson University, 840 Walnut Street, Suite 1020, Philadelphia, PA, 19107, USA.
Jason
J
Hsu
Mid Atlantic Retina, The Retina Service of Wills Eye Hospital, Thomas Jefferson University, 840 Walnut Street, Suite 1020, Philadelphia, PA, 19107, USA. sgarg@midatlanticretina.com.
Sunir
S
Garg
D000287:Administration, Topical; D020533:Angiogenesis Inhibitors / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D019072:Antibiotic Prophylaxis; D001419:Bacteria / Q000187:drug effects / Q000302:isolation & purification*; D016022:Case-Control Studies; D004338:Drug Combinations; D024881:Drug Resistance, Bacterial; D009877:Endophthalmitis / Q000382:microbiology* / Q000517:prevention & control; D015818:Eye Infections, Bacterial / Q000382:microbiology* / Q000517:prevention & control; D006801:Humans; D058449:Intravitreal Injections / Q000009:adverse effects*; D009883:Ophthalmic Solutions; D012189:Retrospective Studies; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors; D014792:Visual Acuity
D020533:Angiogenesis Inhibitors; D000900:Anti-Bacterial Agents; D004338:Drug Combinations; D009883:Ophthalmic Solutions; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A
Antibiotics; Endophthalmitis; Intravitreal injection; Prophylaxis; Resistance