title: Combined ceftazidime and amikacin resistance among Gram-negative isolates in acute-onset postoperative endophthalmitis: prevalence, antimicrobial susceptibilities, and visual acuity outcome.
abstract: BACKGROUND
  The purpose of this study is to evaluate the prevalence, antimicrobial susceptibilities, and visual acuity outcome of acute-onset postoperative Gram-negative bacterial endophthalmitis cases resistant to both ceftazidime and amikacin seen between 2005 and 2010 at L. V. Prasad Eye Institute, a tertiary care ophthalmic Centre in South India. Medical records of all patients with Gram-negative bacterial endophthalmitis resistant to both amikacin and ceftazidime between 1 January 2005 and 31 December 2010 were reviewed in this non-comparative, consecutive, retrospective case series. Favorable outcome was defined as a best-corrected visual acuity of ≥20/200.
  
  
  RESULTS
  Sixty five (39.6%) of 164 culture-positive postoperative endophthalmitis were caused by Gram-negative organisms. Among these 65 isolates, 32 (49%; 95% confidence interval (CI) 37% to 61%) were resistant to ceftazidime, 17 (26%; 95% CI 15% to 37%) to amikacin, and 12 (18.5%; 95% CI 9% to 27%) to both ceftazidime and amikacin. Eight Pseudomonas isolates, three Enterobacter isolates, and one Haemophilus isolate were resistant to both ceftazidime and amikacin. The isolates were sensitive to fluoroquinolones (42%) and imipenem (50%). Presenting visual acuity was light perception in 10 (83.3%) cases. A final visual acuity ≥20/200 was achieved in 5/12 (41.7%) of these patients.
  
  
  CONCLUSIONS
  In the current study, Pseudomonas was the most common Gram-negative bacteria resistant to both amikacin and ceftazidime. The emergence of multidrug-resistant bacteria causing endophthalmitis is a matter of concern in India. Alternative antibiotics like imipenem or fluoroquinolones may be considered for the management of these resistant organisms.
authors.forename: Animesh
authors.initials: A
authors.lastname: Jindal
authors.affiliation: L V Prasad Eye Institute, GMR Varalakshmi Campus, Visakhapatnam 530040, India. avinash@lvpei.org.
authors.forename: Avinash
authors.initials: A
authors.lastname: Pathengay
authors.forename: Manav
authors.initials: M
authors.lastname: Khera
authors.forename: Subhadra
authors.initials: S
authors.lastname: Jalali
authors.forename: Annie
authors.initials: A
authors.lastname: Mathai
authors.forename: Rajeev Reddy
authors.initials: RR
authors.lastname: Pappuru
authors.forename: Raja
authors.initials: R
authors.lastname: Narayanan
authors.forename: Savitri
authors.initials: S
authors.lastname: Sharma
authors.forename: Taraprasad
authors.initials: T
authors.lastname: Das
authors.forename: Harry W
authors.initials: HW
authors.lastname: Flynn