Catheter-related Streptococcus equisimilis bacteremia in a four-month-old infant with congenital cytomegalovirus infection

Methicillin resistance of bacteria isolated from vitreous fluid from patients undergoing vitrectomy

PURPOSE

The aim of this study was to compare the resistance patterns of bacteria in vitreous fluid from patients undergoing vitrectomy for diagnostic reasons, with bacteria of other nosocomial infections.

METHODS

Vitreous fluid samples (n=144) were obtained from 133 patients undergoing vitrectomy for endophthalmitis, and 11 for uveitis as suspected endophthalmitis. They were Gram stained and cultured. Antibiotic susceptibility tests were run on all isolates.

RESULTS

Gram stains were positive in 45/144 cases (31%), among which 38/45 (84%) were confirmed by a positive culture. Cultures were positive in 74/144 patients (51%) with mainly coagulase-negative staphylococci (n = 44) and Staphylococcus aureus (n = 13). In 133 patients endophthalmitis occurred after lens implantation (80 cases) and in 53 cases there was another origin (e.g. corneal transplantation, endogenous). In 26/80 post-lens implantation infections, culture remained negative; 32 infections occurred with coagulase-negative staphylococci, 10 with Staphylococcus aureus, 9 with streptococci and 3 with gram-negative bacteria. For endophthalmitis, ophthalmologists in our institution give an intraocular injection of vanccmycin and ceftazidim after vitrectomy. Among the 44 isolates of coagulase-negative staphylococci, 12 (27%) were resistant to methicillin. This is in contrast to other hospital-related coagulase-negative staphylococcus infections in general, and the resistance rate is 75% in our hospital. Only 2/13 Staphylococcus aureus isolates were methicillin-resistant.

CONCLUSIONS

We conclude that isolates of coagulase-negative staphylococci from vitreous fluid are less resistant to methicillin than those isolated in other nosocomial infections.

Antibiotic susceptibilities of group C and group G streptococci isolated from patients with invasive infections: evidence of vancomycin tolerance among group G serotypes

A retrospective review of medical records for 32 patients with invasive group C streptococcus (GCS) or group G streptococcus (GGS) infections was performed. MICs and minimum bactericidal concentrations (MBCs) of penicillin, erythromycin, and vancomycin for all isolates were obtained. Tolerance of vancomycin, defined as an MBC 32 or more times higher than the MIC, was exhibited by 18 GGS isolates (54%). The identification of tolerance in clinical isolates of GGS and GCS may have clinical implications in treating these seriously ill patients.