Etiology and antibacterial susceptibility pattern of community-acquired bacterial ocular infections in a tertiary eye care hospital in south India

Abstract

Aims:To identify the etiology, incidence and prevalence of ocular bacterial infections, and to assess the in vitro susceptibility of these ocular bacterial isolates to commonly used antibiotics.Materials and Methods:Retrospective analysis of consecutive samples submitted for microbiological evaluation from patients who were clinically diagnosed with ocular infections and were treated at a tertiary eye care referral center in South India between January 2002 and December 2007.Results:A total of 4417 ocular samples was submitted for microbiological evaluation, of which 2599 (58.8%) had bacterial growth, 456 (10.3%) had fungal growth, 15 (0.34%) had acanthamoebic growth, 14 (0.32%) had mixed microbial growth and the remaining 1333 (30.2%) had negative growth. The rate of culture-positivity was found to be 88% (P < 0.001) in eyelids’ infection, 70% in conjunctival, 69% in lacrimal apparatus, 67.4% in corneal, 51.6% in intraocular tissues, 42.9% in orbital and 39.2% in scleral infections. The most common bacterial species isolated were Staphylococcus aureus (26.69%) followed by Streptococcus pneumoniae (22.14%). Sta. aureus was more prevalent more in eyelid infections (51.22%; P = 0.001) coagulase-negative staphylococci in endophthalmitis (53.1%; P = 0.001), Str. pneumoniae in lacrimal apparatus and corneal infections (64.19%; P = 0.001), Corynebacterium species in blepharitis and conjunctivitis (71%; P = 0.001), Pseudomonas aeruginosa in keratitis and dacryocystitis (66.5%; P = 0.001), Haemophilus species in dacryocystitis and conjunctivitis (66.7%; P = 0.001), Moraxella lacunata in blepharitis (54.17%; P = 0.001) and Moraxella catarrhalis in dacryocystitis (63.83%; P = 0.001). The largest number of gram-positive isolates was susceptible to moxifloxacin (98.7%) and vancomycin (97.9%), and gram-negative isolates to amikacin (93.5%) and gatifloxacin (92.7%).Conclusions:Gram-positive cocci were the most frequent bacteria isolated from ocular infections and were sensitive to moxifloxacin and vancomycin, while gram-negative isolates were more sensitive to amikacin and gatifloxacin.

Potential bacterial pathogens of external ocular infections and their antibiotic susceptibility pattern at Hawassa University Teaching and Referral Hospital, Southern Ethiopia

“…The predominant bacterial isolates were S. aureus (21.0%) followed by CoNS (18.2%) and S. pneumoniae (14.0%). This finding is in agreement with previous works elsewhere (Modarrres et al, 1998;Nigatu, 2004;Ubani, 2009;Bharathi et al, 2010 andAnagaw et al, 2011). However, in other studies by Dagnachew et al (2014) and Summaiya et al (2012), the predominant isolates were CoNS.…”

“…In this study, Gram positive cocci are still the most common isolates (61.5%). Several other studies in Ethiopia (Nigatu, 2004;Anagaw et al, 2011;Tewelde et al, 2013 andDagnachew et al, 2014); in India (Sherwal and Verma, 2008;Bharathi et al, 2010;and Ramesh et al, 2010), in Nigeria (Ubani, 2009); in USA (Adebukola et al, 2011) and other parts of world have shown similar results inferring Gram positive cocci as a primary cause of bacterial ocular infection. The predominant bacterial isolates were S. aureus (21.0%) followed by CoNS (18.2%) and S. pneumoniae (14.0%).…”

Risk factors for contact lens-related microbial keratitis in Singapore

“…16,[30][31][32][33] Environmental organisms were recovered in all but one of the culturepositive corneal samples and, although these numbers are low, this finding would be consistent with higher recovery of environmental causative organisms in tropical climate zones. 15 P. aeruginosa is a common environmental pathogen that is able to survive in contact lens storage cases.…”

Pathogenesis of microbial keratitis

“…The resistance of Pseudomonas to disinfectants, coupled with its adherence capability to plastics, facilitates its introduction into the eye where it can react with defective corneal epithelium, gaining further entrance into the corneal stroma. S. pneumonia on the other hand is the major cause of corneal ulcers in developing countries however, some reports emphasize on the fact that Streptococcus are most commonly encountered after P. aeruginosa and/or S. aureus eye infections [14,114,215]. Unlike P. aeruginosa, pneumococcal keratitis is not commonly associated with the use of contact lenses and the predisposing factors often include ocular trauma or surgery [31,104,114,125,160,207].…”