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.


CONCLUSIONS
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.
Panhotra
B R
BR
Department of Infection Control & Microbiology, King Fahad Hospital Al-Hofuf, Al-Hasa, Saudi Arabia. drpanhotra2000@yahoo.co.in
Saxena
A K
AK
Al-Arabi Al-Ghamdi
Ali M
AM
D000208:Acute Disease; D000890:Anti-Infective Agents / Q000627:therapeutic use*; D002939:Ciprofloxacin / Q000627:therapeutic use*; D021821:Communicable Diseases, Emerging; D003967:Diarrhea / Q000188:drug therapy / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial; D005243:Feces / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D009268:Nalidixic Acid / Q000627:therapeutic use*; D015995:Prevalence; D012480:Salmonella Infections / Q000188:drug therapy / Q000382:microbiology*; D012529:Saudi Arabia
D000890:Anti-Infective Agents; D009268:Nalidixic Acid; D002939:Ciprofloxacin