Erythromycin and the newer macrolides

Recent macrolide development has been directed by clinical pharmacology dictates, ethical considerations, and patient concerns. Patient non-compliance, a major repercussion from erythromycin's side-effects, produces lost clientele, resistent bacterial strains, and escalating costs for the patient and healthcare system. Structural alteration of the macrolide molecule (after its macrocyclic lactone ring), has enhanced the antibacterial spectrum, pharmacokinetics, tissue penetration, and drug tolerance. New macrolide derivatives differ from the proto-type (erthromycin) in pharmacokinetic and dynamic profiles, and include roxithromycin, dirithromycin, clarithromycin, and azithromycin. Josamycin is less active than erythromycin. This review discusses the new macrolides widely used in the Caribbean, with reference to erythromycin (AU)

Methicillin resistance among Trinidadian isolates of community and hospital strains of Staphylococcus aureus and their patterns of resistance to non-beta-lactam antibiotics

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains in Trinidad and the extent of their resistance to other antimicrobial agents in hospital-acquired and community-acquired infections were evaluated over a 2-year period. A total of 450 S. aureus strains were isolated from different patients. The prevalence of methicillin resistance among S. aureus strains was 9.8% (44/450). The proportion of MRSA isolated from hospital sources and community sources was 12.5% (38/305) and 4.1% (6/145), respectively (P < 0.05). The resistant rates of MRSA to the non-beta-lactam antibiotics were as follows: 93.2% resistance to tetracycline, 68.2% to erythromycin, 61.4% to gentamicin, 45.5% to co-trimoxazole, and 20.5% to ciprofloxacin. No MRSA resistant to vancomycin was observed in this study. Study results showed significant increases in MRSA in hospital, 2% in 1995 to 12.5% in 1998 (P < 0.05), and community, 0% in 1995 to 4.1% in 1998 (P < 0.05). It has become apparent that infection control and surveillance initiatives must be focused now on the community in order to monitor and limit the spread of this new and expanding reservoir of MRSA.

Methicillin resistance among Trinidadian isolates of community and hospital strains of Staphylococcus aureus and their patterns of resistance to non-beta-lactam antibiotics

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains in Trinidad and the extent of their resistance to other antimicrobial agents in hospital-acquired infections were evaluated over a 2-year period. A total of 450 S. aureus strains were isolated from different patients. The prevalence of methicillin resistance among S. aureus strains was 9.8 percent (44/450). The proportion of MRSA isolated from hospital sources and community sources was 12.5 percent (38/305) and 4.1 percent (6/145) respectively (P<0.05). The resistant rates of MRSA to the non-beta-lactam antibodies were as follows: 93.2 percent resistance to tetracycline, 68.2 percent to erythromycin, 61.4 percent to gentamicin, 45.5 percent to co-trimoxazole, and 20.5 percent to ciprofloxacin. No MRSA resistant to vancomycin was observed in this study. Study results showed significant increases in MRSA in hospital, 2 percent in 1995 to 12.5 percent in 1998 (P<0.05), and community, 0 percent in 1995 to 4.1 percent in 1998 (P<0.05). It has become apparent that infection must be focussed now on the community in order to monitor and limit the spread of this new and expanding reservoir of MRSA. (AU)

Evaluation of oral erythromycin and local isoniazid instillation therapy in infants with Bacillus Calmette-Guerin lymphadenitis and abscesses

A randomized placebo-controlled prospective trial was conducted to evaluate the efficacy of erythromycin therapy in 69 patients affected with Bacillus Calmette-Guerin lymphadenitis. When patients who developed subsequent regional abscesses were excluded, erythromycin caused significantly earlier resolution of lymphadenitis (5.1 months vs. 5.7 months for placebo; p < 0.001) compared with placebo. There was no significant difference in the proportion of patients who developed subsequent regional abscesses between the 2 groups (47 percent for erythromycin, 60 percent for placebo, p = 0.14). When the entire group of 69 patients was evaluated for "duration to heal" (regardless of subsequent abscess formation), erythromycin therapy (4.1 +/- 1.5 sd months) did not differ significantly from the placebo group (3.5 +/- 1.3 months, p = not significant). Patients who develop subsequent abscess (n = 36) along with those with B. Calmette-Guerin regional abcesses at presentation (n = 27) were further studied to compare oral erythromycin therapy with that of single dose 50-mg intranodal isoniazid instillation. Local isoniazid therapy caused significantly earlier resolution of the abscesses (3.9 months) compared with erthromycin therapy (5.2 months; p < 0.001). (AU)