[In vitro activity of moxifloxacin against respiratory pathogens in Latin America]

We compared the in vitro activity of moxifloxacin, levofloxacin and six other antibiotics frequently used in respiratory tract infections, against 1563 Streptococcus pneumoniae, Streptococcus pyogenes, Staphylococcus aureus, Haemophilus influenzae and Moraxella catarrhalis clinical isolates from 21 centers in 10 Latin American countries from March 2000 to April 2001. Moxifloxacin was the most active compound against all the species included. Moxifloxacin was 2- to 4-fold more active than levofloxacin against Gram-positive bacteria. This difference was much higher against levofloxacin-resistant S. pneumoniae isolates (MIC: 0.5 mg/l vs 8 mg/l). The activity of moxifloxacin against H. influenzae and M. catarrhalis was similar to levofloxacin; all the isolates were inhibited at < or = 1 mg/l concentrations of moxifloxacin and levofloxacin.

Activities of BMS 284756 (T-3811) against Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae isolates from SENTRY antimicrobial surveillance program medical centers in Latin America (1999)

The antimicrobial activity of BMS 284756, a novel des-F(6)-quinolone, was comparatively evaluated against 257 Streptococcus pneumoniae, 198 Haemophilus influenzae, and 88 Moraxella catarrhalis strains isolated in Latin America between July and September of 1999 as part of the SENTRY Antimicrobial Surveillance Program. Nearly 28.0% of S. pneumoniae strains were nonsusceptible to penicillin. The rank order of quinolone potency versus S. pneumoniae was BMS 284756 (MIC at which 90% of isolates were inhibited [MIC(90)], 0.12 microg/ml) > trovafloxacin (MIC(90), 0.25 microg/ml) > gatifloxacin (MIC(90), 0.5 microg/ml) > levofloxacin and ciprofloxacin (MIC(90), 1 to 2 microg/ml). All S. pneumoniae strains that were not susceptible to other quinolones were inhibited by BMS 284756 at < or = 2 microg/ml. The overall prevalence of beta-lactamase production was 15.2% in H. influenzae and 98.9% in M. catarrhalis. BMS 284756 showed excellent potency and spectrum against this group of pathogens, inhibiting all isolates at < or = 0.12 microg/ml. BMS 284756 exhibited activity similar to those displayed by the new fluoroquinolones, such as levofloxacin, trovafloxacin, or gatifloxacin, and could be a therapeutic option for empirical treatment of community-acquired respiratory tract infections.

Enterococcus faecalis resistant to vancomycin and teicoplanin (VanA phenotype) isolated from a bone marrow transplanted patient in Brazil

We report for the first time in Brazil, a patient from whom an Enterococcus faecalis VanA phenotype was isolated. Glycopeptide resistance is not commonly observed in Enterococcus faecalis, so this finding is of great concern since this species is responsible for 90% of enterococcal infections in Brazil. The isolate was recovered from a surveillance rectal swab culture from a patient with acute lymphocytic leukemia (ALL). Identification to the species level was performed by conventional biochemical tests and Vitek GPI cards. Antimicrobial susceptibility testing was evaluated by use of broth microdilution and Etest (AB BIODISK, Solna, Sweden) methods. The isolate was identified as E. faecalis and was considered resistant to both vancomycin (MIC, > 256 microg/mL) and teicoplanin (MIC, 256 microg/mL). The isolate also showed high level resistance to gentamicin and streptomycin (MICs, > 1024 microg/mL), but was considered susceptible to ampicillin (MIC, 4 microg/mL). Although the frequency of enterococcal infections is very low in most Latin America countries, the finding of glycopeptide (VanA) resistance in E. faecalis increases concern about apreading antimicrobial resistance in this region.

Nosocomial infections caused by multiresistant Pseudomonas aeruginosa

A case-control study was done to evaluate factors associated with nosocomial infections by multiresistant Pseudomonas aeruginosa (MRPA). Results showed that MRPA was associated with the use of immunosuppressive and antimicrobial drugs. Five typing methods indicated that the MRPA infections were due to multiple strains rather than a single strain.

Staphylococcus aureus prophylaxis in hemodialysis patients using central venous catheter: effect of mupirocin ointment

Central venous catheterization is a common technique to establish rapid and temporary access for hemodialysis. However, it is a known risk factor for Staphylococcus aureus infection and bacteremia. Mupirocin is a topical antibiotic with high in vitro anti-staphylococcal activity. A randomized prospective trial was conducted to assess the effectiveness of mupirocin ointment in the prevention of Staphylococcus aureus skin and catheter colonization, and episodes of bacteremia in 136 end-stage renal disease patients. Of these, 67 received skin disinfection at the venous catheter insertion site with povidone iodine (control group), and 69 received the same treatment followed by application of 2% mupirocin ointment at the cannula site after catheter placement and at the end of each dialysis session. Patients were followed until catheter removal and were monitored for the development of Staphylococcus aureus skin/catheter colonization and episodes of bacteremia. Median duration of catheter use was greater in the mupirocin than in the control group (37 versus 20 d, P < 0.01). Patients in the mupirocin group had a significantly lower rate of Staphylococcus aureus isolation from the pericatheter skin (1.76 per 1000 versus 14.27 per 1000 patient-days, P < 0.001) and from the catheter surface (3.17 per 1000 versus 14.27 per 1000 patient-days, P < 0.001). The proportion of patients with Staphylococcus aureus skin infection at the insertion site was lower in the mupirocin group (4.3% versus 23.9%, P = 0.001). Staphylococcus aureus-associated bacteremia was observed in 17 patients (two in the mupirocin group [0.71 episodes per 1000 patient-days] and 15 in the control group [8.92 per 1000 patient-days], P < 0.001). The hazard ratio of developing Staphylococcus aureus bacteremia was 7.2 (95% confidence interval, 1.6 to 31.6) times greater in patients not receiving mupirocin. Mupirocin applied to the insertion site significantly reduces the risk of Staphylococcus aureus skin and catheter colonization, exit-site infection, and Staphylococcus aureus bacteremia in hemodialysis patients.

[Study of the susceptibility of Staphylococcus sp. and Enterococcus sp. to teicoplanin and vancomycin]

PURPOSE

The study was performed in order to evaluate the susceptibility of Enterococcus and Staphylococcus to teicoplanin and vancomycin.

METHODS

150 Enterococcus strains and 450 Staphylococcus strains (298 Staphylococcus aureus and 152 negative coagulase strains) isolated in three Brazilian hospitals were studied. The MICs were determined using teicoplanin and vancomycin E Test strips. The range of the antimicrobial concentration in each strip went from 256 mcg/mL to 0.016 mcg/mL. Diffusion tests using disks impregnated with 10 mcg of teicoplanin and 30 mcg of vancomycin were also performed.

RESULTS

All the 298 Staphylococcus aureus strains were susceptible to the two antimicrobials. Three of the 152 negative coagulase strains presented intermediate susceptibility to teicoplanin (MICs between 8 and 16 mcg/mL). Four of the 150 Enterococcus strains presented intermediate susceptibility to vancomycin but were totally susceptible to teicoplanin.

CONCLUSION

According to these results teicoplanin and vancomycin are good therapeutical options in the treatment of staphylococcal and enterococcal infections.