Commentary: The changing scenario of cluster endophthalmitis.

The incidence of post cataract surgery endophthalmitis has decreased over time due to better standards of operation theatre sterilization, improved preoperative patient workup, cautious surgical techniques, and better postoperative care.[1] But there are outbreaks of cluster endophthalmitis reported once in a while, especially in a developing country like ours, due to failure in any one of the above-mentioned factors.

An ounce of prevention is worth a pound of cure. But, unfortunately, when things happen, it is better to seek ways to handle and prevent further damage rather than panicking. Cluster endophthalmitis defined as an outbreak of five or more cases on a particular day in a single operating room in one center is a terrifying experience to the institution, operating surgeon, and the patients concerned.[1] An investigative panel works in such a situation to find the cause and to counteract the damage. A proper protocol and guidance for this expert team will always be handy and will maintain uniformity too.

In the current issue of Indian Journal of Ophthalmology, the authors have highlighted the most important steps to be carried out while evaluating cluster endophthalmitis.[2] The immediate measures ideally are to spread awareness, prevent the further outbreak, and to ensure safety of the affected patients. Then a sequence of investigations should be followed to identify the cause of the outbreak.

When looking back and reviewing the literature for evaluating the most common causes of cluster endophthalmitis, some noteworthy facts could be appreciated. Post cataract surgery cluster infections were predominantly reported 10–15 years back, especially in developing Asian countries. The usual causes were attributed to contaminated irrigating fluids, unclean phaco tubings, improper ventilation system, and poor operation room hygiene.[34] But over the past decade or so, the scenario has changed gradually. Nowadays, cluster endophthalmitis are most commonly seen post intravitreal anti-vascular endothelial growth factor (VEGF) injections. With the increasing demand for the low-cost bevacizumab and more possible sources of contamination anywhere in the cold chain, this new bug should be given more importance.[5]

Bevacizumab is widely used off-label to treat these diseases, but it is not available as single dose vials, and therefore, for economic purposes, it is routinely aliquoted into ready-to-use syringes by compounding pharmacies or at the institution of administration.

Hence in today's scenario cluster endophthalmitis has re-emerged due to liberal anti-VEGF use. So, the protocol suggested by the authors might additionally include a note mentioning certain steps such as vigilant surveillance of the anti-VEGF preparation and aliquoting, finding the source of supply, the possible area of contamination of these vials, etc.

The organisms were a mixture of Pseudomonas, Staphylococcus epidermidis, Staphylococcus aureus, etc., in earlier days.[6] But newer entities such as Burkholderia cepacia, Stenotrophomonas maltophilia, etc., are also found responsible for cluster infections currently.[78]

The authors have elaborately discussed the steps to be carried out in an emergency but the discussion is a bit laborious.[2] Hence, in a nutshell, the panel or team should conduct a proper patient workup, evaluate certain entities such as the process of operation theatre sterilization, preoperative patient care, intraoperative techniques and monitor the proper use of irrigating solutions, instruments, phaco tubings, etc.

So, cluster endophthalmitis should not be considered as a petrifying experience anymore. Prevention should always be the priority. But if things go out of hand, the situation must be handled in an organized manner under a specified protocol.