Activity Of Trimethoprim-sulfamethoxazole Research Articles

Group A Streptococcus (Streptococcus pyogenes): the Most Interesting Pathogen in the World

Group A Streptococcus, or Streptococcus pyogenes, is a facultatively anaerobic Gram-positive coccus and one of the most common causes of bacterial infection in humans. The introduction of antibiotics has greatly reduced the morbidity and mortality associated with this organism, but despite uniform susceptibility to treatments of choice, it remains a significant human pathogen. It is particularly problematic in underdeveloped and lower socioeconomic status countries, where hygiene may be suboptimal. This review covers a wide range of topics related to the organism, including diagnosis, treatment, and clinical manifestations. Where possible, the review addresses less conventional and often controversial topics that have not been extensively reviewed elsewhere, such as the activity of trimethoprim sulfamethoxazole against the species, penicillin tolerance, and the use of protein synthesis inhibitors to reduce toxin production and improve outcomes.

ACTIVITY OF TRIMETHOPRIM-SULFAMETHOXAZOLE AGAINST MIDDLE EAR FLUID PATHOGENS OBTAINED FROM COSTA RICAN CHILDREN WITH OTITIS MEDIA

For many years, trimethoprim-sulfamethoxazole (TMP-SMX) has been recommended as an alternative antimicrobial agent for the treatment of children with otitis media (OM). This study analyzed the in vitro activity of TMP-SMX against respiratory pathogens obtained from middle ear fluid of Costa Rican children 6-60 months of age with acute OM, recurrent OM, therapeutic failures and acute OM at risk for having a resistant pathogen. Between 2002 and 2003, a total of 124 middle ear fluid bacterial isolates were analyzed and compared with historic data from 1992 to 1997. A significant increase in the number of TMP-SMX Streptococcus pneumoniae (P = 0.00008)- and Haemophilus influenzae (P = 0.04)-resistant strains was observed during 2002-2003 when compared with strains from 1992-1997.

Removal of the Antibacterial Activity of TrimethoprimSulfamethoxazole, Ofloxacin and Zidovudine by BACTEC Resin-Containing Blood Culture Medium

We determined the capacity of BACTEC resin blood culture media NR 16A and NR 17A to remove the antibacterial activity of trimethoprim-sulfamethoxazole, ofloxacin and zidovudine. Simulated blood cultures containing increasing antibiotic concentrations were inoculated with 10(1), 10(3) and 10(5) CFU/ml blood of various bacterial strains and evaluated with the BACTEC infrared growth detection system. The antibiotic concentrations were adjusted to give breakpoint concentration in the added serum volume or in the total volume of the blood culture vials. Recovery rates and time until detection of bacterial growth in resin-media were compared with those in resin-free media. Trimethoprim-sulfamethoxazole and ofloxacin were, similar to piperacillin, inactivated by resins at antibiotic concentrations that were up to ten times higher than those easily achievable in serum. The antimicrobial effect of zidovudine on gram negative bacteria was reduced in resin media at concentrations corresponding to fifteen times the peak serum levels. Growth of P. aeruginosa, but not of S. aureus, E. coli, K. pneumoniae and Salmonella, was delayed in the presence of resins even at subinhibitory antibiotic concentrations when compared with resin-free media.

In vitro susceptibilities of nonfermentative gram-negative bacilli other than Pseudomonas aeruginosa to 32 antimicrobial agents.

The animal inhibitory concentrations of 32 antimicrobial agents for 322 strains of non-fermentative gram-negative bacilli, representing 30 species and unnamed groups other than Pseudomonas aeruginosa, were determined in cation-supplemented Mueller-Hinton broth with use of a microdilution method. The activities of beta-lactam antibiotics varied, but azlocillin, mezlocillin, piperacillin, cefotaxime, and moxalactam consistently were more active than were available penicillins and cephalosporins; the penicillin-like antibiotic mecillinam was less active. The activities of the aminoglycoside antibiotics were similar to each other although streptomycin and sometimes kanamycin were less active than the other aminoglycosides. Although minocycline and doxycycline usually were more active than tetracycline, the percentages of strains susceptible to the first two drugs at concentrations achievable in vivo were only occasionally higher than the percentage of strains susceptible to tetracycline. The activity of trimethoprim-sulfamethoxazole was variable. Chloramphenicol, erythromycin, clindamycin, and vancomycin were relatively inactive against most of the organisms tested, but the high degrees of activity of these drugs against specific species or strains, particularly those that were resistant to many drugs, indicated potential clinical usefulness of these agents.