scholarly journals Antimicrobial Drug Resistance of Salmonella enterica Serovar Typhi in Asia and Molecular Mechanism of Reduced Susceptibility to the Fluoroquinolones

2007 ◽  
Vol 51 (12) ◽  
pp. 4315-4323 ◽  
Author(s):  
Tran Thuy Chau ◽  
James Ian Campbell ◽  
Claudia M. Galindo ◽  
Nguyen Van Minh Hoang ◽  
To Song Diep ◽  
...  

ABSTRACT This study describes the pattern and extent of drug resistance in 1,774 strains of Salmonella enterica serovar Typhi isolated across Asia between 1993 and 2005 and characterizes the molecular mechanisms underlying the reduced susceptibilities to fluoroquinolones of these strains. For 1,393 serovar Typhi strains collected in southern Vietnam, the proportion of multidrug resistance has remained high since 1993 (50% in 2004) and there was a dramatic increase in nalidixic acid resistance between 1993 (4%) and 2005 (97%). In a cross-sectional sample of 381 serovar Typhi strains from 8 Asian countries, Bangladesh, China, India, Indonesia, Laos, Nepal, Pakistan, and central Vietnam, collected in 2002 to 2004, various rates of multidrug resistance (16 to 37%) and nalidixic acid resistance (5 to 51%) were found. The eight Asian countries involved in this study are home to approximately 80% of the world's typhoid fever cases. These results document the scale of drug resistance across Asia. The Ser83→Phe substitution in GyrA was the predominant alteration in serovar Typhi strains from Vietnam (117/127 isolates; 92.1%). No mutations in gyrB, parC, or parE were detected in 55 of these strains. In vitro time-kill experiments showed a reduction in the efficacy of ofloxacin against strains harboring a single-amino-acid substitution at codon 83 or 87 of GyrA; this effect was more marked against a strain with a double substitution. The 8-methoxy fluoroquinolone gatifloxacin showed rapid killing of serovar Typhi harboring both the single- and double-amino-acid substitutions.

2018 ◽  
Vol 5 (2) ◽  
pp. 22-25 ◽  
Author(s):  
Damodar Gajurel ◽  
Rabi Prakash Sharma ◽  
Krishna Dhungana ◽  
Samir Neupane ◽  
Kamal Lamsal ◽  
...  

INTRODUCTION: Drug resistant Salmonella spp. is endemic in several Asian countries. Nalidixic acid-resistant Salmonella enterica serovar Typhi and Salmonella enterica serovar Paratyphi A show reduced susceptibility to fluoroquinolones and have resulted in a rise in treatment failures. Over the past few decades, nalidixic acid-resistant Salmonella spp have emerged in Nepal as well.MATERIAL & METHODS: This is a retrospective study that aims to provide a more recent antibiogram of S. Typhi and S. Paratyphi A isolates in Kathmandu. Between Poush, 2071 and Ashwin, 2072 (December 16, 2014 to October 17, 2015), 186 culture positive cases of enteric fever were diagnosed at the Civil Service Hospital. Upon isolation of S. Typhi or S. Paratyphi A, antimicrobial susceptibility testing was performed with amoxicillin, azithromycin, ceftriaxone, chloramphenicol, ciprofloxacin, cotrimoxazole, nalidixic acid, ofloxacin and tetracyciline.RESULTS: This study shows a much higher frequency of nalidixic acid-resistance in Kathmandu than previously reported; 95.7% in Salmonella enterica serovar Paratyphi A and 86.5% in Salmonella enterica serovar Typhi.The rates of ciprofloxacinand ofloxacin-resistance were over 50% in both serovar.CONCLUSION: In Nepal, it is necessary to reevaluate the use of fluoroquinolone therapy and introduce feasible alternatives so as to curb treatment failures.Journal of Universal College of Medical Sciences (2017) Vol. 5, No, 2, Page: 22-25


2010 ◽  
Vol 54 (12) ◽  
pp. 5201-5208 ◽  
Author(s):  
Christopher M. Parry ◽  
Chau Tran Thuy ◽  
Sabina Dongol ◽  
Abhilasha Karkey ◽  
Ha Vinh ◽  
...  

ABSTRACT Infections with Salmonella enterica serovar Typhi isolates that have reduced susceptibility to ofloxacin (MIC ≥ 0.25 μg/ml) or ciprofloxacin (MIC ≥ 0.125 μg/ml) have been associated with a delayed response or clinical failure following treatment with these antimicrobials. These isolates are not detected as resistant using current disk susceptibility breakpoints. We examined 816 isolates of S. Typhi from seven Asian countries. Screening for nalidixic acid resistance (MIC ≥ 16 μg/ml) identified isolates with an ofloxacin MIC of ≥0.25 μg/ml with a sensitivity of 97.3% (253/260) and specificity of 99.3% (552/556). For isolates with a ciprofloxacin MIC of ≥0.125 μg/ml, the sensitivity was 92.9% (248/267) and specificity was 98.4% (540/549). A zone of inhibition of ≤28 mm around a 5-μg ofloxacin disc detected strains with an ofloxacin MIC of ≥0.25 μg/ml with a sensitivity of 94.6% (246/260) and specificity of 94.2% (524/556). A zone of inhibition of ≤30 mm detected isolates with a ciprofloxacin MIC of ≥0.125 μg/ml with a sensitivity of 94.0% (251/267) and specificity of 94.2% (517/549). An ofloxacin MIC of ≥0.25 μg/ml and a ciprofloxacin MIC of ≥0.125 μg/ml detected 74.5% (341/460) of isolates with an identified quinolone resistance-inducing mutation and 81.5% (331/406) of the most common mutant (carrying a serine-to-phenylalanine mutation at codon 83 in the gyrA gene). Screening for nalidixic acid resistance or ciprofloxacin and ofloxacin disk inhibition zone are suitable for detecting S. Typhi isolates with reduced fluoroquinolone susceptibility.


Author(s):  
Girija Roka ◽  
Subash Pandaya ◽  
Md. Reyad-ul Ferdous ◽  
Manson Pandey ◽  
Naba Raj Pokhrel ◽  
...  

The present study determined the susceptibility to ciprofloxacin of nalidixic acid resistant <em>Salmonella</em> (NARS) isolated from enteric fever patients at Scheer Memorial Hospital, Banepa, Nepal, from June 2012 to December 2012. The antimicrobial sensitivity to nalidixic acid and ciprofloxacin was determined using modified Kirby-Bauer disc diffusion and broth dilution method according to the guidelines of the Clinical and Laboratory Standard Institute. <em>Salmonella</em> was isolated from 34 out of 992 (3.43%) blood cultures collected during the study period, and 10 (29.4%) isolates were identified as <em>Salmonella enterica</em> serotype Typhi, while 24 (70.6%) were identified as <em>Salmonella enterica</em> serotype Paratyphi. Out of the total isolates, 31 (91.2%) were nalidixic acid-resistant <em>Salmonella</em> (NARS). Among NARS, the minimum inhibitory concentration values for ciprofloxacin ranged from 0.25 to 2 mg/L and were constantly higher than those shown by the nalidixic acid-susceptible <em>Salmonella</em>. Therefore, in typhoid <em>Salmonella</em> nalidixic acid resistance may be the indicator of decreased susceptibility to ciprofloxacin.


1999 ◽  
Vol 37 (1) ◽  
pp. 266-269 ◽  
Author(s):  
Christine Heurtin-Le Corre ◽  
Pierre-Yves Donnio ◽  
Monique Perrin ◽  
Marie-France Travert ◽  
Jean-Loup Avril

We determined the resistance to quinolone of 309 Salmonella enterica subsp. enterica serotype Typhimurium strains isolated from humans and animals (cattle, pigs, or poultry) in 1995 or 1996. Nalidixic acid resistance increased from 8.5% in 1995 to 18.6% in 1996. The highest resistance levels correlated with a mutation at Ser-83 (or Asp-82). All strains remained ciprofloxacin susceptible. Human and animal isolates were compared by pulsed-field gel electrophoresis, and the banding patterns of the human isolates most closely matched those of the bovine isolates.


2017 ◽  
Vol 73 (9) ◽  
pp. 561-566
Author(s):  
Beata Wysok ◽  
Joanna Wojtacka ◽  
Agnieszka Wiszniewska – Łaszczych ◽  
Joanna Szteyn ◽  
Małgorzata Gomółka–Pawlicka

The aim of the study was to determine the presence of Campylobacter strains in poultry by-products and define antimicrobial resistance of isolates. In total, 400 samples were tested among which 300 included the liver, heart and stomach, and 100 samples represented the contents of the cecum. The samples were taken from chickens and turkeys in the slaughterhouse after evisceration. The prevalence of Campylobacter in chicken samples was 100% with regards to the contents of cecum and offal. The turkey origin Campylobacter strains were noted in 76% of the livers, 78% hearts and 82% gizzards. The samples of cecum contents were positive in 60%. Species analysis of the strains isolated showed C. jejuni as dominant. The estimation of sensitivity to antibiotics showed that Campylobacter strains were most frequently resistant to quinolones and tetracyclines. Resistance to ciprofloxacin was detected among 52.7% and 52.5% chicken and turkey origin strains. The same was noted regarding nalidixic acid, resistance to which was shown in 56% and 58.5% isolates, respectively. Regarding tetracyclines, the highest resistance of the strains from chicken and turkey was detected to doxycyclinum in 61.3% and 53.3% of isolates, respectively. However the highest sensitivity was showed to erythromycin, gentamicin and chloramphenicol. Only one C. coli strain from turkey offal was resistant to gentamicin. Simultaneously multi drug resistance was defined. The aimed studies showed that 62% of C. jejuni and 53.8% of C. coli strains from chicken offal were resistant to two or more agents. In turkey origin isolates MDR was detected in 54.7% of C. jejuni and 53.3% of C. coli strains.


2003 ◽  
Vol 47 (12) ◽  
pp. 3719-3723 ◽  
Author(s):  
Young Sook Jeong ◽  
Je Chul Lee ◽  
Hee Young Kang ◽  
Hak Sun Yu ◽  
Eun Young Lee ◽  
...  

ABSTRACT The resistance to ampicillin and nalidixic acid in Shigella sonnei isolates obtained in Korea during the period 1998 to 2000 was characterized. Recently (J. Y. Oh, H. S. Yu, S. K. Kim, S. Y. Seol, D. T. Cho, and J. C. Lee, J. Clin. Microbiol. 41:421-423, 2003) ampicillin and nalidixic acid resistance was found in 49 and 70%, respectively, of the 67 S. sonnei isolates obtained during this period. We analyzed 138 S. sonnei isolates collected during the same period. Ampicillin and nalidixic acid resistance was found in 30 and 86% of the isolates, respectively. The ampicillin resistance was mediated by a TEM-1β -lactamase, and TEM-52 extended-spectrum β-lactamase was identified in one sporadic S. sonnei isolate from 1999. bla TEM-1 and bla TEM-52 were located in conjugative R-plasmids. Tn3 was detected in 41% of the ampicillin-resistant isolates. The R-plasmids from the transconjugants that transferred resistance to ampicillin exhibited different restriction fragment length polymorphism patterns, and a bla TEM-1 probe was hybridized with the different fragments. The nalidixic acid resistance was exclusively associated with an amino acid substitution, Ser83→Leu (TCG→TTG), in gyrA. These findings indicate that the genetically related S. sonnei strains readily acquire resistance to ampicillin, streptomycin, trimethoprim, and sulfamethoxazole but not nalidixic acid through conjugative R-plasmids from difference sources when confronted by antibiotic selective pressures.


2006 ◽  
Vol 51 (1) ◽  
pp. 195-197 ◽  
Author(s):  
Jennifer E. Stevenson ◽  
Kathryn Gay ◽  
Timothy J. Barrett ◽  
Felicita Medalla ◽  
Tom M. Chiller ◽  
...  

ABSTRACT Fluoroquinolones commonly are used to treat adult Salmonella infections. Fluoroquinolone treatment has failed for persons infected with nalidixic acid-resistant Salmonella. From 1996 to 2003, state public health laboratories forwarded 12,252 non-Typhi Salmonella enterica isolates to the Centers for Disease Control and Prevention for antimicrobial susceptibility testing; 203 (1.6%) of the isolates were nalidixic acid resistant, and 14 (7%) of those were ciprofloxacin resistant. Resistance to nalidixic acid significantly increased from 0.4% in 1996 to 2.3% in 2003. All ciprofloxacin-resistant isolates had at least one point mutation in the quinolone resistance determining region (QRDR) of gyrA and did not harbor qnr or have point mutations in the QRDR of gyrB, parC, or parE. Continued surveillance of antimicrobial resistance among non-Typhi S. enterica isolates is needed to mitigate the increasing prevalence of nalidixic acid resistance.


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