Authors: Neelam Taneja ([email protected]), Manisha Biswal, Shivpriya, Pooja Rao, and Prashant Sood
Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, India
Increasing antibiotic resistance has emerged as a major challenge in the treatment of shigellosis as multi-drug-resistant Shigellae are being increasingly reported. Fluoroquinolones are often used in the treatment of shigellosis in this part of India. At the 1,359-bed tertiary care referral centre of Postgraduate Institute of Medical Education and Researach, which caters to a population of >4 million in neighbourhood of Chandigarh, North India, antibiotic resistance in Shigellae is being constantly monitored due to changes in the serogroup distribution and increasing antibiotic resistanace. In 2003, there was an outbreak of ciprofloxacin-resistant Shigella dysenterae serotype 1, which caused a serogroup shift which soon reverted in 2004 to S. flexneri. Ciprofloxacin-resistant S. dysenteriae serotype 1 has caused outbreaks in Northeast India and Bangladesh leading to a regional alert in South Asia. Ciprofloxacin resistance in S. flexneri has been reported sporadically from various countries.
The present communication reports an alarming level of ciprofloxacin resistance in S. flexneri that has emerged as a therapeutic challenge in the region. Methodology: Shigellae isolated from stool samples were identified by the standard biochemical methods and confirmed by serotyping. Antibiotic
susceptibility was performed as per the NCCLS guidelines. Minimum inhibitory concentration (MIC) for nalidixic acid and ciprofloxacin was performed by the agar dilution method of NCCLS and E-test respectively. Clinical and treatment details of patients were noted.
Of 40 Shigellae isolated from 793 stool samples (5%), submitted over a 10-month period in 2005, 21 (52.5%) were S. flexneri (isolated from 19 patients). Age of patients ranged from 3 months to 50 years (12 children, 7 adults). All children were aged less than 5 years. Acute dysentery was the commonest presentation with an average duration of illness of 11.3 days. All strains were resistant to nalidixic acid (MIC >128). Sixteen (84,2%) patients had ciprofloxacin MIC from 8 to 64. All patients were treated with ciprofloxacin/ofloxacin which are the drugs of choice in the region. Six patients, who were given ceftriaxone (2 patients) and amikacin (4 patients), did not show any clinical response. Three patients showed partial response, who also responded to amikacin.
Forty-seven percentage of patients either did not respond or responded partially to fluoroquinolones. Due to indiscriminate use, fluoroquinolones will soon be ineffective in the region for the treatment of shigellosis.