In vitro activity of ampicillin, cefoperazone, their combinations with sulbactam and other antimicrobials: survey of Russian isolates.

Methodological differences makes it difficult to compare results of antimicrobial susceptibility testing obtained in Russia and in other regions. During the period from October 1993 to May 1994 susceptibility of 1296 isolates of bacteria was investigated according to NCCLS standards by the broth microdilution method. The order of activity of antibiotics against Gram-negative bacteria based on percent of susceptible strains from common hospitals were: amikacin (98%) > ciprofloxacin (93%) = imipenem (93%) > cefoperazone/sulbactam (92%) > ceftazidime (89%) > ceftriaxone (81%) > cefotaxime (80%) > cefoperazone (77%) > gentamicin (71%) > ampicillin/sulbactam (51%) > cefazoline (45%) > ampicillin (25%). The order of activity against strains from teaching hospitals was similar but the percent of susceptible strains was 10-20% less for the majority of antibiotics. The susceptibility level of Gram-negative isolates from Moscow teaching hospitals is lower than from Northern America and Europe. Ampicillln/sulbactam and cefoperazone/sulbactam, as well as other cephalosporins, demonstrated high activity against methicillin-susceptible staphylococci and penicillin-susceptible pneumococci. B-lactams/beta-lactamase inhibitor combinations were active against 100% strains of anaerobic bacteria.

[Microtest-system for detection of urinary tract infections]. / Mikrotest-sistema dlia vyiavleniia infektsii mochevyvodiashchikh putei.

A rapid physico-chemical method for detection of clinically significant bacteriuria is described. The method is based on turbidimetric detection of the bacterial growth after 6-hour incubation of the urine specimens in the wells of the microtest system which is a polysterol plate used in immunological studies with 96 wells (8 x 12 cm) of the volume of 0.2 ml each containing a dry medium.

[Comparative in vitro activity of ampicillin, cefoperazone, their combinations with sulbactam and other antibiotics with respect to staphylococci and pneumococci]. / Sravnitel'naia aktivnost' in vitro ampitsillina, tsefoperazona, ikh kombinatsii s sul'baktamom i drugikh antibiotikov v otnoshenii stafilokokkov i pnevmokokkov.

Antibiotic susceptibility of 225 Staphylococcus strains and 42 Pneumococcus strains was assayed with the method of serial microdilutions. Methicillin resistant Staphylococcus strains (S. aureus and coagulase negative strains) were characterized by high susceptibility to cephalosporins and ampicillin + sulbactam combination, as well as to ciprofloxacin, rifampicin and vancomycin (70 to 100 per cent of the susceptible strains). Less than 50 per cent of the strains was susceptible to erythromycin. The methicillin resistant Staphylococcus strains preserved their high susceptibility to vancomycin and rifampicin (the coagulase negative strains also preserved their susceptibility to ciprofloxacin). Four Pneumococcus strains with the intermediate resistance to benzylpenicillin were isolated (for 9.6 per cent of the strains the MIC was 0.12 to 1.0 micrograms/ml). The growth of 2 out of these 4 strains was inhibited by the ampicillin + sulbactam combination in a concentration of less than 0.5 micrograms/ml and by cefotaxime and the cefoperazone + sulbactam combination in a concentration of less than 1.0 micrograms/ml. The growth of the other 2 strains was inhibited by betalactams in concentrations higher than the above mentioned.

[Microturbidimetric method for determining the activity of polymyxin M]. / Mikroturbidimetricheskii metod opredeleniia aktivnosti polimiksina M.

A microturbidimetric procedure for the assay of polymyxin M activity was developed. The assay is performed in polystyrene 96-well plates usually used for immunological tests.

[Comparative in vitro activity ampicillin, cefoperazone, their combinations with sulbactam, as well as that of other antibiotics against aerobic gram-negative microorganisms]. / Sravnitel'naia aktivnost' in vitro ampitsillina, tsefoperazona, ikh kombinatsii s sul'baktamom, a takzhe drugikh antibiotikov v otnoshenii aérobnykh gramotritsatel'nykh mikroorganizmov.

The activity of 12 antibiotics against 849 strains of gram-negative aerobes isolated in special and general hospitals of Moscow and Smolensk in 1992-1993 was assayed with the method of serial microdilutions. By the criteria of the activity (percentage of the susceptible strains by the NSSLS criteria) against the isolates the antibiotics were arranged as follows: ciprofloxacin (89.8 per cent) > imipenem (89.6 per cent) > cefoperazone + sulbactam (86.1 per cent) > amikacin (83.8 per cent) > ceftazidime (81.8 per cent) > ceftriaxone (71.1 per cent) > cefoperazone (70.9 per cent) > cefotaxime (70.9 per cent) > gentamicin (60.8 per cent) > ampicillin + sulbactam (44.7 per cent) > cefazolin (37.5 per cent) > ampicillin (23.0 per cent). The frequency of the antibiotic susceptible isolates in the special hospitals was lower at the average by 20 per cent than that in the general hospitals with respect to all the antibiotics assayed.