Methicillin-sensitive S. aureus

To prevent development of resistance and promote synergy, inhaled tobramycin or colistin is usually added to an oral fluoroquinolone for P. aeruginosa coverage.1,3 Methicillin-sensitive S. aureus (MSSA) may be treated with oral amoxiciUin-clavulanic acid, dicloxacillin, first- or second-generation cephalosporins, trimethoprim-sulfamethoxazole, or clindamycin, depending on sensitivity. Likewise, methiciUin-resistant S. aureus (MRSA) may be treated with oral trimethoprim-sulfamethoxazole, clindamycin, minocycline, or linezolid. H. influenzae often produces... 

The antibiotics of choice for treating methicillin-sensitive S. aureus (MSSA) infections are penicillinase-stable penicillins and first-generation cephalosporins. 

MSSA methicillin-sensitive S. aureus MRSA methicillin-resistant S. aureus NBTE nonbacterial thrombotic endocarditis... 

Fourth-Generation Cephalosporins. The fourth-generation cephalosporin, cefepime, has an extended spectrum of activity against both gram-positive (e.g., methicillin-sensitive S. aureus) and gram-negative organisms (e.g.. Pseudomonas). 

The recommended therapy for patients with left-sided IE caused by methicillin-sensitive S. aureus (MSSA) is 4 to 6 weeks of naf-cUlin or oxacillin, often combined with a short course of gentamicin (see Table 109-6). Erom in vitro studies, the combination of an aminoglycoside and peniciUinase-resistant penicillin or vancomycin enhances the activity of these drugs toward MSSA. In animal models of endocarditis, combinations of penicillin with an aminoglycoside eradicate organisms from vegetations more rapidly than penicillins... 

A study in 8 healthy subjects found that rifampicin 900 mg daily for 10 days decreased the half-life and AUC0.12 of pefloxacin 400 mg twice daily by about 30%, due to a 35% increase in total plasma clearance. Despite these changes the serum pefloxacin levels still remained well above the minimal inhibitory concentrations (0.5 mg/L) for 90% of strains of methicillin-sensitive S. aureus and S. epidermis A single-dose study in 5 healthy subjects found that pefloxacin 500 mg increased the AUC of a single 600-mg dose of rifampicin by about twofold. In a further study the urinary recovery of rifampicin was increased from 15.6% of the dose to 20.1% by pefloxacin. ... 

Table 11.1 Overview of studies for profiling human pathogens with MALDI-TOF MS at the strain level Examples of strain categorization (A), strain differentiation (B), and strain identification (C). MRSA methicillin-resistant Staphylococcus aureus, MSSA methicillin-sensitive S. aureus, L library-based approach, P proteomics-based approach, CHCA a-cyano-4-hydroxycinnamic acid, CMBT 5-chloro-2-mercaptobenzothiazole, DHB 2-hydroxy-5-methoxy benzoic acid, FA ferulic acid, HABA 2,4-hydroxyphenylazobenzoic acid, SA 3,5-dimethoxy-4-hydroxycinnamic acid (sinapinic acid), THAP 2,4,6-trihydroxyacetophenon. Adapted and modified from Sandrin et al. (2013)... 

Mupirocin (pseudomonic acid A) is structurally unrelated to other currently available topical antibacterial agents. Most gram-positive aerobic bacteria, including methicillin-resistant S aureus (MRSA), are sensitive to mupirocin (see Chapter 50). It is effective in the treatment of impetigo caused by S aureus and group A -hemolytic streptococci. 

The effectiveness of moxifloxacin (MIC,) 0.06-0.125 mg L ) against methicil-lin-sensitive S. aureus (MSSA) is four- to eight-fold greater than that of ciprofloxacin, ofloxacin, and levofloxacin, although its in vitro activity against methicillin-resistant S. aureus (MRSA) is less powerful (MIQo 1-8 mg L 1) [33,149,150, 182,186],... 

Racemosol and demethylracemosols, together with their possible biogenetic precursors, preracemosols A and B (175 and 176) exhibited moderate antimalarial activity with ECso values of 0.9, 2.0, 18.0 and 3.0 / g/ml, respectively [101]. The antibacterial activity pattern of the two photosensitizers, dehydroeffusol and juncusol, against methicillin-resistant and -sensitive S. aureus and B. subtilis was similar to that of their antifungal activity [456]. 

The penicillinase-resistant penicillins [methicillin, nafcillin, oxacillin, cloxacillin, and dicloxacillin] have less potent antimicrobial activity against microorganisms that are sensitive to penicillin G, but they are the agents of first choice for treatment of penicillinase-producing S. aureus and S. epidermidis that are not methicillin-resistant. 

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