Treatment of Streptococcal Endocarditis with a Single Daily Dose of Ceftriaxone and Netilmicin for 14 Days: A Prospective Multicenter Study

A 2-week course of ceftriaxone (2 g) plus netilmicin (4 mglkg), administered as one short daily iv infusion, was evaluated for the treatment of streptococcal endocarditis in an open multicenter study. Of the 52 patients, 31 were infected with viridans streptococci, 18 with Streptococcus bovis, two with Gemella morbillorum, and one with group C Streptococcus; 48 patients were assessable. Infection was cured in 42 cases, 35 treated medically and seven treated both medically and surgically. Five patients died without evidence of active infection, and one relapsed. The bacteriologic failure was due to a strain of G. morbillorum against which no synergy of ceftriaxone and netilmicin was evident in vitro. The serum creatinine level increased during treatment in four cases, all involving patients >65 years old who had renal risk factors; in two of these cases, values did not return to baseline during follow-up. Of 40 patients assessed for auditory function, only one developed decreased perception of borderline significance. Other adverse reactions were mild. This regimen was efficacious, safe, and cost-effective for the treatment of streptococcal endocarditis. However, it must be used with caution for patients with preexisting renal impairment or concomitant exposure to other potentially nephrotoxic agent

Faucets as a reservoir of endemic Pseudomonas aeruginosa colonization/infections in intensive care units

Objective: To evaluate the role of faucets as a reservoir for Pseudomonas aeruginosa colonization/infection of patients hospitalized in intensive care units (ICUs). Design: Prospective epidemiological investigation performed during a nonepidemic period of 1year. The inner part of the ICU faucets were swabbed for P. aeruginosa. Data were recorded on all patients with at least one culture of a clinical specimens positive for P. aeruginosa. Pulsed-field gel electrophoresis was used to characterize the strains. Setting: Five ICUs of a university hospital which are supplied by two separate water distribution networks. Patients: During a 1-year period 132 cases were investigated. Results: In 42% of cases (56/132) there were isolates identical to those found in the faucets, with a total of nine different genotypes. Among the nine genotypes isolated from both patients and faucets one of them, the most prevalent, was isolated in the two networks and in 30 cases. The other eight genotypes were recovered almost exclusively from either one (three genotypes in 12 cases) or the other (five genotypes in 12 cases) network and from the patients in the corresponding ICUs. Conclusions: These results suggest that the water system of the ICUs was the primary reservoir of patient's colonization/infection with P. aeruginosa in a substantial proportion of patients, although the exact mode of acquisition could not be determine

Mechanisms of Successful Amoxicillin Prophylaxis of Experimental Endocarditis Due to Streptococcus intermedius

Prophylaxis with amoxicillin (40 mg/kg) was studied in rats with aortic valve vegetations. Bacteria on the valves were quantitated early (10 min to 6 hr) and late (three days) after intravenous challenge with tolerant Streptococcus intermedius. Amoxicillin reduced by 40% the number of bacteria per valve 10 min after intravenous challenge with 105 S. intermedius (P < .05) and by 74% the incidence of endocarditis three days thereafter (P < .0001). Bacterial multiplication started 2 hr after challenge in control rats, whereas bacteria disappeared in 6 hr in amoxicillin-treated rats. Intravenous penicillinase 30 min after challenge abolished successful amoxicillin prophylaxis, a result demonstrating the necessity of prolonged growth inhibition for protection. Growth inhibition for 18 hr (two subsequent amoxicillin doses) was necessary for protection after intravenous challenge with 105 S. intermedius. Thus, in the absence of bacterial killing, inhibition of valvular colonization by amoxicillin was not as important a mechanism of endocarditis prophylaxis as was prolonged inhibition of bacterial growth, which allowed adherent bacteria to be cleared from the valve

Treatment of streptococcal endocarditis with a single daily dose of ceftriaxone and netilmicin for 14 days: a prospective multicenter study

A 2-week course of ceftriaxone (2 g) plus netilmicin (4 mg/kg), administered as one short daily iv infusion, was evaluated for the treatment of streptococcal endocarditis in an open multicenter study. Of the 52 patients, 31 were infected with viridans streptococci, 18 with Streptococcus bovis, two with Gemella morbillorum, and one with group C Streptococcus; 48 patients were assessable. Infection was cured in 42 cases, 35 treated medically and seven treated both medically and surgically. Five patients died without evidence of active infection, and one relapsed. The bacteriologic failure was due to a strain of G. morbillorum against which no synergy of ceftriaxone and netilmicin was evident in vitro. The serum creatinine level increased during treatment in four cases, all involving patients &gt; 65 years old who had renal risk factors; in two of these cases, values did not return to baseline during follow-up. Of 40 patients assessed for auditory function, only one developed decreased perception of borderline significance. Other adverse reactions were mild. This regimen was efficacious, safe, and cost-effective for the treatment of streptococcal endocarditis. However, it must be used with caution for patients with preexisting renal impairment or concomitant exposure to other potentially nephrotoxic agents

Occult nosocomial infections

Even with a good surveillance program, nosocomial infections may be not recognized because of several reasons: absence of symptoms or prolonged incubation period (eg, viral bloodborne infections, tuberculosis); problems with the microbiological diagnosis, because adequate specimens may be difficult to obtain or special methods should be used (eg, fungal infections, virus, new agents); shorter hospital stays (eg, surgical-site infections); difficulty in distinguishing between nosocomial and community-acquired infections (eg, influenza); and failure to detect clinically relevant colonization (eg, multiresistant microorganisms). Because of the important potential consequences of occult nosocomial infections, specific surveillance programs should be designed to address these problems

Molecular epidemiology of methicillin-resistant Staphylococcus aureus at a low-incidence hospital over a 4-year period

OBJECTIVE: To study the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) over a prolonged period of time with the aid of a molecular typing method (ribotyping). SETTING: A 1,000-bed tertiary university medical center. PATIENTS AND METHODS: Defined epidemiological data were recorded for all patients culture-positive for MRSA between 1989 and 1992. Ribotyping of MRSA strains was performed using three restriction enzymes: EcoRV, HindIII, and KpnI. RESULTS: From 1989 to 1992, MRSA was isolated from clinical specimens in 98 patients and from surveillance cultures in 27 patients. Among the 122 isolates available for typing, 26 different ribotypes were identified. In 20% of the cases, MRSA was community-acquired, and a third of these patients never had been hospitalized previously. Nine ribotypes were responsible for more than one case (2 to 64 patients); 17 appeared only once. Epidemiological data correlated with ribotyping results revealed 14 epidemiologic clusters involving six different ribotypes, whereas only three outbreaks were suspected initially. The median follow-up after the last isolation of a given ribotype was 14 months (range, 1 to 42) for clusters and 25 months (range, 1 to 46) for ribotypes that appeared only once. During clusters, only 16% of the cases occurred after the implementation of control measures in the ward (breakthrough cases). CONCLUSIONS: The high diversity of MRSA strains observed over 4 years suggested that new strains were introduced continuously in our hospital. Furthermore, that 17 ribotypes were isolated only once, that breakthrough cases represented only 16% of the cases in clusters, and that the follow-up duration after the last isolation of a given ribotype was more than 14 months suggest that infection control measures were effective in limiting the nosocomial spread of MRSA over a prolonged period of time

Unusual Spread of a Penicillin-Susceptible Methicillin-Resistant Staphylococcus aureus Clone in a Geographic Area of Low Incidence

We describe the unusual spread of a penicillin-susceptible methicillin-resistant Staphylococcus aureus (MRSA) clone in hospitals in western Switzerland, where the incidence of MRSA is usually low. During a 2-year period, this clone had been responsible for several outbreaks and had been isolated from >156 persons in 21 institutions. Molecular typing by pulsed-field gel electrophoresis (PFGE) demonstrated that all of these isolates belonged to the same clone. In 1 of the outbreaks, involving 30 cases, the clone was responsible for at least 17 secondary cases. In contrast, during the period of the latter outbreak, 9 other patients harboring different MRSA strains, as assessed by PFGE, were hospitalized in the same wards, but no secondary cases occurred. These observations suggest that this clone, compared with other MRSA strains, had some intrinsic factor(s) that contributed to its ability to disseminate and could thus be considered epidemi

Faucets as a reservoir of endemic Pseudomonas aeruginosa colonization/infections in intensive care units

OBJECTIVE: To evaluate the role of faucets as a reservoir for Pseudomonas aeruginosa colonization/infection of patients hospitalized in intensive care units (ICUs). DESIGN: Prospective epidemiological investigation performed during a nonepidemic period of 1 year. The inner part of the ICU faucets were swabbed for P. aeruginosa. Data were recorded on all patients with at least one culture of a clinical specimens positive for P. aeruginosa. Pulsed-field gel electrophoresis was used to characterize the strains. SETTING: Five ICUs of a university hospital which are supplied by two separate water distribution networks. PATIENTS: During a 1-year period 132 cases were investigated. RESULTS: In 42% of cases (56/132) there were isolates identical to those found in the faucets, with a total of nine different genotypes. Among the nine genotypes isolated from both patients and faucets one of them, the most prevalent, was isolated in the two networks and in 30 cases. The other eight genotypes were recovered almost exclusively from either one (three genotypes in 12 cases) or the other (five genotypes in 12 cases) network and from the patients in the corresponding ICUs. CONCLUSIONS: These results suggest that the water system of the ICUs was the primary reservoir of patient's colonization/infection with P. aeruginosa in a substantial proportion of patients, although the exact mode of acquisition could not be determined