Gram-positive organisms

Because of the highly permeable nature of the ced wad of gram-positive organisms, they produce P-lactamases which are not only found throughout the ced wad, but also in the extracedular environment. Hence the extracedular P-lactamases can act on the antibiotic before the ced is entered. 

Susceptible Gram-positive organisms such as Streptococcus pneumoniae and /3-lactamase-negative Staphylococcus aureus. 

The lincosamides, another group of anti-infectives, are effective against many gram-positive organisms, such as streptococci and staphylococci. However, because of their high potential for toxicity, the lincosamides are usually used only for the treatment of serious infections in which penicillin or erythromycin (a macrolide) is not effective... 

The 6-j3-amidinopenicillanic acids, mecillinam and its ester pivmeeillinam, have unusual antibacterial properties, since they are active against Gram-negative but not Gram-positive organisms. 

The genus Staphylococcus is traditionally associated with disease in humans. The demonstration (Monna et al. 1993) that a strain of Staphylococcus auriculans—isolated by enrichment with dibenzofuran and with no obvions clinical association—could degrade this substrate and carry out limited biotransformation of hnorene and dibenzo[l,4]dioxin serves to illustrate the unsuspected metabolic potential of facultatively anaerobic Gram-positive organisms. 

The enantiomeric reduction of 2-nitro-l-phenylprop-l-ene has been studied in a range of Gram-positive organisms including strains of Rhodococcus rhodochrous (Sakai et al. 1985). The enantiomeric purity of the product depended on the strain used, the length of cultivation, and the maintenance of a low pH that is consistent with the later results of Meah and Massey (2000). It has been shown that an NADPH-linked reduction of a,p-unsaturated nitro compounds may also be accomplished by old yellow enzyme via the flcf-nitro form (Meah and Massey 2000). This is formally analogous to the reduction and dismutation of cyclic enones by the same enzyme (Vaz et al. 1995), and the reductive fission of nitrate esters by an enzyme homologous to the old yellow enzyme from Saccharomyces cerevisiae (Snape et al. 1997). 

Pharmacologic management of infections should cover the gram-positive organisms that most frequently cause access-related infections. Patients who have positive blood cultures should receive treatment tailored to the organism isolated. Preventive measures for access-related infections include mupirocin at the exit site and povidone-iodine ointment. The recommendations of the NKF for treatment of infections associated with hemodialysis are listed in Table 23-9. 

Initial antibiotic choice should always cover gram-positive organisms (e.g., vancomycin 20 mg/kg intravenously with serum concentration monitoring or cefazolin 20 mg/kg intravenously 3 times... 

Although almost any type of organism is capable of causing IE, the majority of cases are caused by gram-positive organisms (Table 71-1). These consist primarily of streptococci,... 

Vancomycin may be added to the empirical regimen after 3 to 5 days in persistently febrile patients or if cultures reveal gram-positive organisms. Vancomycin should be changed if the gram-positive organism is susceptible to other antibacterials or discontinued in patients with persistent fever after 3 days with negative cultures. 

Antoine, R. and Locht, C. (1992) Isolation and molecular characterization of a novel broad-host-range plasmid from Bordetella bronchiseptica with sequence similarities to plasmids from Gram-positive organisms. Molecular Microbiology, 6, 1785-1799. 

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