Epidemiological analysis of notified measles cases and review of surveillance system during an outbreak in Tabuk, Saudi Arabia.

PURPOSE: In response to a measles outbreak occurred in Tabuk, Saudi Arabia, we conducted a case-based active-surveillance, and analyzed all surveillance data to identify the epidemiology of notified measles cases and to review the surveillance system. METHODS: Suspected and confirmed measles cases were defined according to World Health Organization (WHO) guidelines. Household-based investigation was conducted for all suspected cases using standard measles notification form. Enzyme-linked immunosorbent assay was carried out on serum samples collected from all suspected cases to detect measles specific immunoglobulin M (IgM) antibodies. Surveillance system was assessed by preselected performance indicators consistent with WHO guidelines. Logistic regression was used to calculate crude and adjusted odds ratios from the surveillance data. RESULTS: Of 242 suspected measles cases notified between 3rd and 48th calendar weeks of the study-year, laboratory result was IgM-positive for 46% cases, IgM-negative for 49% cases, and unknown for 5% cases. Suspected and confirmed cases separately showed urban-predominance (>77%), male-majority (>51%), and high-proportion among Saudis (>92%). The highest proportion (93%) of suspected cases that received "at least one dose" of measles-containing vaccine (MCV) was found among those aged 12-17 years, whereas the lowest proportion (17%) was observed among the adult individuals (> or =18 years). Elderly (> or =18 years) individuals were significantly less likely to be vaccinated than younger (1-5 years) children (adjusted odds ratio [OR] = 15.92, 95% confidence interval [CI] = 4.82-52.56). The vaccine failure rate for "at least one dose" of MCV was 35%. The individuals vaccinated with "at least one-dose" of MCV were at 3.6 times lower risk of contracting measles than the nonvaccinated group (adjusted OR = 3.6, 95% CI = 1.55-8.38). Of five surveillance performance indicators, three were found as per WHO target. CONCLUSIONS: More efforts are essential to prevent future outbreaks and to reach the goal of measles elimination in the country.

Emerging nalidixic acid and ciprofloxacin resistance in non-typhoidal Salmonella isolated from patients having acute diarrhoeal disease.

BACKGROUND: Non-typhoidal Salmonella are one of the key etiological agents of diarrhoeal disease. The appearance of multiple drug resistance along with resistance to quinolones in this bacterium poses a serious therapeutic problem. We determined the prevalence of nalidixic acid and ciprofloxacin resistance in non-typhoidal Salmonella isolated from faecal samples of patients with acute diarrhoeal disease attending the outpatient and inpatient departments of a hospital in Saudi Arabia during the years 1999 to 2002. METHODS: Non-typhoidal Salmonella were isolated from faecal samples. Antimicrobial susceptibility was tested by the disc diffusion test. MICs to nalidixic acid and ciprofloxacin were determined by the agar dilution method. RESULTS: During the study period, 524 strains of non-typhoidal Salmonella were isolated. Strains belonging to serogroup C1 were the commonest (41.4%) followed by serogroups B and D (15.6% and 14.5%, respectively). Resistance to ampicillin was observed in 22.9% and to trimethoprim/sulfamethoxazole in 18.5% of the strains. Nalidixic acid resistance was encountered in 9.9% and ciprofloxacin resistance in 2.3% of the strains. Resistance to nalidixic acid significantly increased from 0.1% in 1999 to 5.5% in 2002 (P=0.0007) and ciprofloxacin resistance increased significantly from 0.1% in 1999 to 0.9% in 2002 (P=0.0001). MICs to nalidixic acid and ciprofloxacin were determined among 29 nalidixic acid-resistant strains of non-typhoidal Salmonella isolated during 2002. The MIC was >256 microg/mL to nalidixic acid and 8 to 16 microg/mL to ciprofloxacin. CONCLUSION: The increasing rates of antimicrobial resistance encountered among non-typhoidal Salmonella necessitate the judicious use of these drugs in humans. Moreover, these findings support the concern that the use of quinolones in animal feed may lead to an increase in resistance and should be restricted.