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D L Shungu

Publications and source records attributed to D L Shungu.

22 records · Page 2Linked to original sources
PubMed1979

Morphological and physiological study of autolytic-defective Streptococcus faecium strains.

Three autolytic-defective mutants of Streptococcus faecium (S. faecalis ATCC 9790) were isolated. All three autolytic-defective mutants exhibited the following properties relative to the parental strain: (i) slower growth rates, especially in chemically defined medium; (ii) decreased rates of cellular autolysis and increased survival after exposure to antibiotics which block cell wall biosynthesis; (iii) decreased rates of cellular autolysis when treated with detergents, suspended in autolysis buffers, or grown in medium lacking essential cell wall precursors; (iv) a reduction in the total level of cellular autolytic enzyme (active plus latent forms of the enzyme); (v) an increased ratio of latent to active forms of autolysin; and (vi) increased levels of both cellular lipoteichoic acid and lipids.

Anti-Bacterial Agents↗
PubMedDate not supplied

In vitro activities of antibacterial agents against clinical isolates of Escherichia coli and Klebsiella species from intensive care units.

The susceptibility of 293 cultures of Escherichia coli and 160 cultures of Klebsiella species isolated consecutively from patients in intensive care units at 25 New York area hospitals to four antibiotic agents was determined. Susceptibility testing was performed with the reference agar dilution and broth microdilution procedures. At the minimum inhibitory concentration (MIC) breakpoints (specified in the prescribing information) of less than or equal to 4 micrograms/ml for imipenem, less than or equal to 16 micrograms/ml for cefoxitin, less than or equal to 8 micrograms/ml for ampicillin/sulbactam, and less than or equal to 64 micrograms/ml for ticarcillin/clavulanic acid, all isolates tested were susceptible to imipenem, 98% each of E coli and Klebsiella isolates were susceptible to cefoxitin, 75% and 83% to ampicillin/sulbactam and 96% and 92% to ticarcillin/clavulanic acid. At the recommended National Committee for Clinical Laboratory Standards MIC breakpoints (less than or equal to 4 micrograms/ml for imipenem, less than or equal to 8 micrograms/ml for cefoxitin, less than or equal to 8/4 micrograms/ml for ampicillin/sulbactam, and less than or equal to 16/2 micrograms/ml for ticarcillin/clavulanic acid) all isolates were susceptible to imipenem, 97% of E coli and 98% of Klebsiella isolates were susceptible to cefoxitin, 75% and 83% to ampicillin/sulbactam, and 86% each to ticarcillin/clavulanic acid. Of the 122 isolates with MICs greater than or equal to 128 micrograms/ml to ampicillin, only 19% were susceptible to ampicillin/sulbactam; and of the 150 isolates with MICs greater than 128 micrograms/ml to ticarcillin, 61% were susceptible to ticarcillin/clavulanic acid. The results suggest that, in the antibiotic combinations studied, high levels of penicillinases, capable of significantly affecting the utility of the enzyme inhibitors, are produced.

Ampicillin↗
PubMedDate not supplied

Comparative activity of cefoxitin, ampicillin/sulbactam, and imipenem against clinical isolates of Escherichia coli and Klebsiella pneumoniae.

The in vitro activities of cefoxitin, ampicillin/sulbactam, and imipenem were determined by the standard twofold agar dilution method against 62 strains of Escherichia coli and 40 strains of Klebsiella pneumoniae isolated from patients in intensive care units. Judging from the concentrations required to inhibit at least 90% of the test isolates, imipenem (MIC90 less than or equal to 0.125 micrograms/ml) was markedly more active than cefoxitin (MIC90 = 4 micrograms/ml) and ampicillin/sulbactam (MIC90 = 32 micrograms/ml) against both bacterial genera. Cefoxitin, therefore, was more active than ampicillin/sulbactam against these organisms. Breakpoints specified in the prescribing information are less than or equal to 4 micrograms/ml for imipenem, less than or equal to 16 micrograms/ml for cefoxitin, and less than or equal to 8 micrograms/ml for ampicillin/sulbactam. At these breakpoints all organisms were susceptible to imipenem and cefoxitin, while 73% of E coli and 78% of K pneumoniae were susceptible to ampicillin/sulbactam. At recommended susceptible MIC breakpoints of the National Committee for Clinical Laboratory Standards (less than or equal to 4 micrograms/ml for imipenem, less than or equal to 8 micrograms/ml for cefoxitin, and less than or equal to 4 micrograms/ml for ampicillin/sulbactam) all the isolates tested were susceptible to imipenem, while 98% and 73% of the E coli isolates were susceptible to cefoxitin and ampicillin/sulbactam, respectively, and 100% and 78% of the K pneumoniae isolates were susceptible to cefoxitin and ampicillin/sulbactam, respectively. Approximately 14% of E coli and 17% of K pneumoniae isolates were resistant to ampicillin/sulbactam (MIC greater than or equal to 32/16 micrograms/ml).

Ampicillin↗