Multi-drug resistance and reduced susceptibility to ciprofloxacin among Salmonella enterica serovar Typhi isolates from the Middle East and Central Asia

Abstract

Typhoid fever is common in developing countries, with an estimated 120 million infections and 700 000 annual deaths, worldwide. Fluoroquinolones have been the treatment of choice for infection with multidrug-resistant (MDR) Salmonella enterica serovar Typhi (S. Typhi). However, alarming reports of fluoroquinolone-resistance and failure of typhoid fever treatment have recently been published. To determine the proportion of S. Typhi isolates with reduced susceptibility to ciprofloxacin (RSC) from six countries in the Middle East and Central Asia, 968 S. Typhi isolates collected between 2002 and 2007 from Egypt, Uzbekistan, Pakistan, Qatar, Jordan and Iraq were tested for antibiotic susceptibility to five antibiotics using the disc-diffusion method. MDR was defined as resistance to amicillin, chloramphenicol and trimethoprim-sulfamethoxazole. The E-test was employed to determine the MIC of ciprofloxacin only. Nalidixic acid resistance was evaluated as a marker for RSC. Interpretations were made according to CLSI guidelines. MDR strains were considerably more prevalent in Iraq (83%) and Pakistan (52%) compared with the other countries studied (13–52%). Nearly all isolates were susceptible (99.7%) to ceftriaxone. RSC was detected in a total of 218 isolates (22%), mostly from Iraq (54/59, 92%), Uzbekistan (98/123, 80%), Qatar (23/43, 54%) and Pakistan (31/65, 47%). Many of these (21%) were also MDR. Use of nalidixic acid resistance as an indicator for RSC was 99% sensitive and 98% specific. This study reinforces the need for routine antimicrobial susceptibility surveillance of enteric fever isolates and close review of current therapeutic policies in the region.

Incidence rates and clinical Symptoms of Salmonella, Vibrio parahaemolyticus, and Shigella infections in China, 1998–2013

“…Diverse resistance patterns of various Salmonella strains to different antibiotics were found in our clinical study, which may be due to the different medical treatment expertise of doctors [17,20]. Nagshetty et al [17] reported that the percentage of Salmonella Typhi isolates resistant to ciprofloxacin in India was 4.2%, while the susceptibility of Salmonella to ciprofloxacin in the present study was 79.7%.…”

Susceptibility to patterns of ciprofloxacin among nalidixic acid-resistant Salmonella isolates collected in Banepa, Nepal from enteric fever patients

“…The use of antibiotics prior to blood collection may possibly explain the low isolation rate of Salmonella in Nepal, since antibiotics are frequently prescribed even for mild cases of fever. 9,10 The numbers of S. Paratyphi (41.18 %) were comparatively higher than S. Typhi. Increasing prevalence of S. Paratyphi has been reported from several studies worldwide including Nepal.…”

“…High incidence of NARS isolates, ranging from 73.3 to 94.9%, was described from different studies held in Nepal. 4,10,13 Nalidixic acid screening has been suggested to detect and predict decreased ciprofloxacin susceptibility in enteric fever causing Salmonella. 14,15 In our study, all 34 NARS isolates were found to be sensitive to ciprofloxacin by routine disc diffusion tests.…”

Towards sustainable public health surveillance for enteric fever

“…Before antibiotics were available, in one hospital in Indonesia 26% of patients hospitalized with blood culture confirmed Salmonella Typhi died [1]. Although most patients infected with strains of Salmonella Typhi and Salmonella Paratyphi A, B and C respond well to currently available antibiotics, the emergence of widespread antimicrobial resistance has undermined the effectiveness of commonly used antimicrobials [2][3][4]. There is little short term prospect for development of new effective low-cost drugs [5,6].…”