Plasmodium vivax is the second most important cause of morbidity in Ethiopia. There is, however, little information on P. vivax resistance to chloroquine and chloroquine plus primaquine treatment although these drugs have been used as the first line treatment for over 50 years. We assessed the efficacy of standard chloroquine and chloroquine plus primaquine treatment for P. vivax infections in a randomized open-label comparative study in Debre Zeit and Nazareth in East Shoa, Ethiopia. A total of 290 patients with microscopically confirmed P. vivax malaria who presented to the outpatient settings of the two laboratory centers were enrolled: 145 patients were randomized to receive CQ and 145 to receive CQ+PQ treatment. Participants were followed-up for 28-157 days according to the WHO procedures. There were 12 (6.5%) lost to follow-up patients and 9 (3.1%) withdrawals. In all, 96% (277/290) of patients were analysed at day 28. Baseline characteristics were similar in all treatment groups. In all, 98.6% (275/277) of patients had cleared their parasitemia on day 3 with no difference in mean parasite clearance time between regimens (48.34+/-17.68, 50.67+/-15.70 h for the CQ and CQ+PQ group, respectively, P=0.25). The cumulative incidence of therapeutic failure at day 28 by a life-table analysis method was 5.76% (95% CI: 2.2-14.61) and 0.75% (95% CI: 0.11-5.2%) in the CQ and CQ+PQ group, respectively (P=0.19). The relapse rate was 8% (9/108) for the CQ group and 3% (4/132) for the comparison group (P=0.07). The cumulative risk of relapse at day 157 by a life-table method was 61.8% (95% CI: 20.1-98.4%) in the CQ group, compared with 26.3% (95% CI: 7.5-29.4%) in the CQ+PQ group (P=0.0038). The study confirms the emergence of CQ and PQ resistance/treatment failure in P. vivax malaria in Ethiopia. Although treatment failures were detected, they were similar between the treatment groups. We recommend regular monitoring and periodic evaluation of the efficacy of these antimalarial drugs in systematically selected sentinel sites to detect further development of resistance and to make timely national antimalarial drug policy changes.

Streptococcus pneumoniae is the leading cause of community acquired pneumonia and a frequent cause of otitis media, sinusitis and meningitis. Although most pneumococci remain susceptible to penicillin, relatively less susceptible and resistant strains have been recognized with increasing frequency throughout the world (1). The aim of this study was to determine whether and to what degree pneumococci isolated in our laboratory were resistant to penicillin and other frequently used antimicrobial agents.During the period from 1991 to 1995 1139 Streptococcus pneumoniae strains isolated from patients with different pneumococcal infections were tested for their susceptibility to antimicrobial agents at the Department of Bacteriology and Parasitology of the Institute of Public Health in Novi Sad. Antimicrobial agents tested included: penicillin, ampicillin, cephalexin, erythromycin, sulfamethoxazole-trimethoprim and clindamycin. Susceptibility test was performed by using Kirby-Bauer disc diffusion technique on Mueller-Hinton agar supplemented with 5% defibrinated bovine blood (5).Susceptibility of Streptococcus pneumoniae to seven antimicrobial agents used in the study is shown in Table 2. There was a resistance to all antimicrobial agents tested. It was the lowest to erythromycin (1.6%) and the highest to sulfamethoxazole+ trimethoprim (67.3%). The rate of resistance of penicillin was 3.3%. In Table 3 and 4 we can also see that the lowest resistance was to erythromycin, and the highest to sulfamethoxazole+trimethoprim, both for isolates from nose and other sources. Strains of Streptococcus pneumoniae isolated from nasal swabs were more susceptible to penicillin than those isolated from blood, sputum and cerebrospinal fluid.For many years penicillin has been the mainstay of therapy for pneumococcal diseases. Clinical resistance to penicillin was first reported in 1960's. Since this early reported, penicillin resistance has been encountered with increasing frequency in strains of Streptococcus pneumoniae from around the world. In our study resistance to penicillin was low (3.3%). This is in accordance with the authors from Italy, Great Britain, USA and Germany (7, 8, 9, 10). Much higher prevalence of resistant pneumococci we found in the reports from Spain, France and Hungary (13, 14, 15, 17). Many of these strains have been resistant to multiple drugs and have been isolated from patients with invasive infections (meningitis, pneumonia, bacteremia). Percentage of penicillin resistant pneumococci isolated from blood, sputum and cerebrospinal fluid in our study was relatively low (7.7%), but it was higher than the percentage of resistant isolates from nasal swabs (2.0%). These findings are in accordance with other reports (20, 21).The increasing number of Streptococcus pneumoniae isolates resistant to penicillin and other antimicrobial agents indicates the need to perform susceptibility testing for every isolated strain in order to avoid possible therapeutic failure.