Postoperative endophthalmitis is a serious complication of cataract and intraocular lens implantation surgery; the incidence ranges from 0.07 to 0.12% (Kresloff et al. 1998). Many previous studies had reported outbreaks of post cataract surgery endophthalmitis caused by P. aeruginosa (Guerra et al. 2012; Pathengay et al. 2012; Hoffmann et al. 2002; Mateos et al. 2006; Pinna et al. 2010; Sunenshine et al. 2009a; Centers for Disease Control and Prevention (CDC) 1992; Sunenshine et al. 2009b; Ramappa et al. 2015; Kenchappa et al. 2009; Arsan et al. 1996). One of the Pseudomonas endophthalmitis outbreaks compromised large numbers of cases of 45 patients with 45 affected eyes in 2-day period (Guerra et al. 2012).This study included six eyes of six patients (six cultures positive for Pseudomonas) in 1-day period. Pseudomonas aeruginosa is a saprophytic Gram-negative bacterium that is widely distributed in water, soil, and plants. P. aeruginosa is an important opportunistic pathogen in health care-associated infections (HAI) (Hoffmann et al. 2002). The P. aeruginosa epidemics seem to be related to contaminated intraocular irrigating solutions (Guerra et al. 2012; Mateos et al. 2006), lens solution (Ramappa et al. 2015), and trypan blue dye (Mateos et al. 2006; Sunenshine et al. 2009a), in povidone-iodine solution (Pinna et al. 2010), at the phacoemulsifier fluid circulation (Pathengay et al. 2012; Hoffmann et al. 2002; Pinna et al. 2010; Eifrig et al. 2003; Cruciani et al. 1998; Zaluski et al. 1999) and air-conditioning units (Boks et al. 2006). In this study, we could not identify the exact source of the outbreak as all the screened environmental samples gave negative results. However, the reused reprocessed cassette of the phaco-machine was used in common for all cases of phacoemulsification performed that day in operative room OT4. The cassette was disposed of in the infectious bag before the next day of operative surgery; no sample could be obtained for pathogen isolation.
Single-use items must be discarded after single use only or reprocessed using validated methods following instructions of FDA regulations (Grohmann 2018), or national regulations because of the following: cleaning and decontamination become inadequate with reuse of instrument. This can be due to instrument construction (e.g., small bore), or surface damage occurring, preventing removal of all debris or organisms. Component materials of the instrument may be damaged, leading to the risk of falling of fragments into the eye during the operation. Some materials can adsorb or absorb certain chemicals, potentially causing harm (Grohmann 2018).
Before disconnecting the hand piece from the unit of phacoemulsification machine, the hand piece’s ports, tips, and tubing should be flushed. By flushing the hand piece, we can prevent build-up of material (which is difficult to remove) by cleaning inside the hand piece, thus preventing its occlusion. If the tips of hand pieces become occluded, several centers consider that a potential cause of toxic anterior segment syndrome (TASS) (Swaddiwudhipong et al. 1995). Many bacterial species including Pseudomonas species have the ability to form biofilms in different environments as a defense against predation. A biofilm comprises microorganisms multicellular communities in which cells stick to each other and also to a surface. These cells are embedded in an extracellular slimy matrix. The biofilm bacteria are sheltered from harmful factors in the environment, such as antibiotics, and a host body’s immune system. Biofilms may form on living or non-living surfaces, such as implants and tubing. Biofilm formation is an obstacle concerning the uses and design of ocular devices, such as contact lenses, conjunctival plugs, intraocular lenses, scleral buckles, lacrimal intubation devices, phacoemulsifier internal tubing, and orbital implants (Bispo et al. 2015).
Since improper reprocessing of surgical instruments is a major cause in postoperative endophthalmitis, it will be beneficial to follow the recommendations of Ophthalmic Surgery Centers regarding sterilization practices (Sebrell 2009; Graybill-D'Ercole 2013) which include the following: avoid using the antiquated term, “flash sterilization.” Cleaning and rinsing instruments is an important step in their reprocessing after its use. Manufacturer’s instructions must be followed starting from cleaning, disinfection, and for type and time of sterilization of instrument. Guard against recontamination while transporting and storing sterile instruments. A written policy should be in the place to ensure implementation of the proper procedures.
Primary vitrectomy is the recommended treatment for acute endophthalmitis patients with light perception according to the Endophthalmitis Vitrectomy Study (EVS). Better visual acuity should have antibiotic injection intravitreal, after withdrawing intraocular fluid sample for microbial culture (Endophthalmitis Vitrectomy Study Group EVSG 1995). Chen et al. (2011) suggested that vitrectomy (primary or secondary) reduces the likelihood of evisceration, In our study, three patients were submitted to primary vitrectomy, five of cases were re-operated upon and received injection of antibiotic intravitreally, and no patient underwent evisceration or enucleation in a 3-month follow-up. The severity of clinical aspect at the presentation of endophthalmitis was important for choosing the treatment performed. Generally, there is poor visual prognosis despite the intravitreal antibiotics treatment even in cases with sensitive microbial isolates (Pinna et al. 2010). In a previous literature, describing P. aeruginosa outbreak of post-cataract endophthalmitis, the outcome was evisceration or phthisis in 10 (50%) of 20 eyes, and only 5 eyes had minimum degree of improvement (Pinna et al. 2010). In another study by Eifrig et al.; 18 (64%) of 28 eyes with P. aeruginosa endophthalmitis underwent either enucleation or evisceration and none of the 9 patients with post-cataract endophthalmitis reached a final visual acuity of 5/200 or better (Eifrig et al. 2003).
In our study, six patients reported outcome, three of them reached final acuity of light perception, two with hand movement and one patient with amblyopic eye showed marked improvement in signs but needs more time to improve visual acuity due to amblyopia. None of these eyes underwent evisceration.
The good visual outcome in some of these cases could be due to the prompt recall of patients as soon as diagnosis of endophthalmitis was reached and the treatment was given (anterior chamber irrigation, primary vitrectomy, and intravitreal antibiotics).
At the first moment, broad spectrum antibiotics for injection were chosen to cover Gram-positive and Gram-negative bacteria before microbial culture results. The safety and effectiveness of vancomycin and ceftazidime combined has been reported in experimental studies using mice and confirmed in human case series (Endophthalmitis Vitrectomy Study Group EVSG 1995; Yoshizumi et al. 1999).
P. aeruginosa has intrinsic resistance which explains its resistant to second-generation penicillins, tetracycline, chloramphenicol, and narrow-spectrum and expanded-spectrum cephalosporin. Antibiotic-resistant isolates of Pseudomonas show increasing prevalence (Kuznar 2017).
Multidrug-resistant P. aeruginosa is defined as those strains resistant to 3 or more classes of antibiotics including: penicillins (piperacillin, ticarcillin, and piperacillin-tazobactam), cephalosporins (ceftazidime and cefepime), monobactams, aminoglycosides, and fluoroquinolone antibiotics (Pinna et al. 2010).
In our study, resistance to cefotaxime, ceftazidime, cefoperazone, cefuroxime, Cefepime, aztreonam, ampicillin-sulbactam, gentamycin, tobramycin, amikacin, fucidene, and trimethoprim-sulfamethoxazol was observed. The other antibiotics tested (imepenem, meropenem, piperacillin-tazobactam, polymixin B, levofloxacin, ofloxacin, and moxifloxacin) were effective on the isolated Pseudomonas. This result, except sensitivity to amikacin was consistent with the one reported by Gad et al. (2007). However, another study by (Falavarjani et al. 2017) showed similar results; sensitivity to ciprofloxacin and imipenem100% but more sensitivity pattern to cephalosporin (ceftazidime in 83.4%) and aminoglycosides (amikacin in 88.3%). This discrepancy can be explained by the fact that antibiotic-resistant isolates of Pseudomonas show increasing prevalence in different parts of the world (Kuznar 2017).