[In vitro susceptibility testing of 446 clinical isolates of gram-positive bacteria to new quinolones, carbapenems and cephalosporins].
OBJECTIVE
To assess the in vitro susceptibility of gram-positive bacteria isolated in the São Paulo Hospital against five fluoroquinolones, three carbapenems and three cephalosporins.


METHODS
Susceptibility was tested in 77 isolates of streptococci, 38 enterococci, 25 S. aureus and 91 S. epidermidis. The strains were isolated in the São Paulo Hospital in June and July of 1992. The susceptibility testing was performed by broth microdilution according to the procedure described by the national committee for Clinical Laboratory Standards (NCCLS). The antimicrobial agents tested were: ciprofloxacin, ofloxacin, levofloxacin, grepafloxacin (formerly OPC 17116), DU-6859, imipenem, meropenem, biapenem, ceftazidime, cefepime and FK-037.


RESULTS
The best in vitro activity was demonstrated by the new fluoroquinolones, especially DU 6859. Among the commercially available compounds, the fluoroquinolones ciprofloxacin and ofloxacin (81% susceptibility) and the carbapenem imipenem (74% susceptible) were the most active compounds. The highest resistance rates were shown by enterococci and oxacillin-resistant staphylococci.


CONCLUSIONS
The results of the present study showed that the in vitro activities of the new carbapenems are similar to that of imipenem and the fourth generation cephalosporins are more active than ceftazidime against gram-positive bacteria. In addition, the newer fluoroquinolones were four to sixteen-fold more active than that showed by the commercially available compounds of this class, especially against enterococci and oxacillin-resistant staphylococci. These results indicate that these newer fluoroquinolones should be further evaluated in clinical trials.
Cereda
R F
RF
Disciplina de Doenças Infecciosas e Parasitárias da Universidade Federal de São Paulo.
Pignatari
A C
AC
Leme
I L
IL
Jones
R N
RN
Sader
H S
HS
D015780:Carbapenems / Q000494:pharmacology*; D002511:Cephalosporins / Q000494:pharmacology*; D016983:Enterococcus / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D006801:Humans; D008826:Microbial Sensitivity Tests; D015363:Quinolones / Q000494:pharmacology*; D013210:Staphylococcus / Q000187:drug effects; D013291:Streptococcus / Q000187:drug effects
D015780:Carbapenems; D002511:Cephalosporins; D015363:Quinolones