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Antimicrobial resistance patterns and prevalence of class 1 and 2 integrons in Shigella flexneri and Shigella sonnei isolated in Uzbekistan
Ruslan S Madiyarov, Amir M Bektemirov, Gulnara A Ibadova, Gulnara K Abdukhalilova, Aybek V Khodiev, Ladaporn Bodhidatta, Orntipa Sethabutr, Carl J Mason
Gut Pathogens , 2010, DOI: 10.1186/1757-4749-2-18
Abstract: We studied 31 isolates of S. flexneri and 21 isolates of S. sonnei isolated in Uzbekistan between 1992 and 2007 for the susceptibility or resistance to ampicillin (Am), chloramphenicol (Cl), tetracycline (Te), co-trimoxazole (Sxt), kanamycin (Km), streptomycin (Str), gentamicin (Gm), cefazolin (Czn), cefoperazone (Cpr), cefuroxime (Cur), ceftazidime (Ctz), nalidixic acid (NA) and ciprofloxacin (Cip). Am/Str/Cl/Te and Am/Str/Cl/Te/Sxt resistance patterns were found most frequently in S. flexneri. Single isolates were resistant to aminoglycoside, quinolones and cephalosporins. The resistance patterns were different in the two species. Integrons were detected in 93.5% of S. flexneri (29/31) and 81.0% of S. sonnei (17/21) isolates. In addition, 61.3% of S. flexneri (19/31) isolates and 19.0% of S. sonnei (4/21) isolates carried both classes of integrons. In 29.0% of S. flexneri (9/31) isolates, only class 1 integrons were identified. In S. flexneri isolates, the presence of class 1 integrons was associated with resistance to ampicillin and chloramphenicol. Only Class 2 integrons were present in 61.9% of S. sonnei (13/21) isolates.Our study documents antibiotic resistance among Shigella spp. in Uzbekistan. Ninety percent of Shigella strains were resistant to previously used antibiotics. Differences among S. flexneri and S. sonnei isolates in patterns of antimicrobial resistance to routinely used shigellosis antibiotics were observed. The majority of S. flexneri were resistant to ampicillin, chloramphenicol, tetracycline and streptomycin. Class 1 and 2 integrons were widely present in these Shigella strains. Resistance to ampicillin/chloramphenicol was associated with the presence of class 1 integrons. Though several mechanisms are possible, the resistance of Shigella isolates to ampicillin/chloramphenicol may be associated with the expression of genes within class 1 integrons.Shigellosis is an acute enteric infection caused by Shigella species and manifested by diarrhea.
In vitro adhesion and invasion inhibition of Shigella dysenteriae, Shigella flexneri and Shigella sonnei clinical strains by human milk proteins
Emerson Willer, Renato de Lima, Loreny Giugliano
BMC Microbiology , 2004, DOI: 10.1186/1471-2180-4-18
Abstract: Our revealed showed that both adhesion and invasion of Shigella species were inhibited by low concentration of secretory immunoglobulin A, lactoferrin and free secretory component. This work also showed that, these proteins bind to superficial and whole-cell Shigella proteins.Our findings suggest that human milk may act inhibiting adhesion and, consequently, invasion of Shigella, thereafter preventing shigellosis in infants.Shigella species are common etiological agents of shigellosis. This illness is responsible for 500,000 deaths of children per year, in developing countries [1]. Clinical symptoms of shigellosis mainly due to acute inflammatory responses, are characterized by the presence of blood and mucus in the stools and intense damage of colonic epithelium. Of the four species of Shigella, three are frequently isolated from dysentery cases: S. dysenteriae, S. flexneri and S. sonnei [2].For many enteropathogens, adhesion to the host cells, mediated by either fimbrial or afimbrial adhesins, has been shown to be the primordial step of intestinal colonization [3]. However, in Shigella, adhesion structures have not been well characterized and the importance of the adhesion process for colonization and pathogenesis remains unclear [4]. Conversely, the ability to invade epithelial cells has been largely studied in S. flexneri. A 230 kDa plasmid that encodes many invasion proteins (invasion plasmid antigens – Ipas) and proteins of the type III secretion system (Mxi-Spa), was shown to be essential for the invasion process, allowing the entrance in human colonic cells, intracellular multiplication and spreading to adjacent cells [5].Many epidemiological studies have shown that breastfeeding protects infants against intestinal infections [6-9]. Immunoglobulins, mainly the secretory immunoglobulin A (sIgA) [10,11], glycocompounds [10,12] and oligosaccharides [13] have been implicated in the protection conferred by human milk against different enteropathogens.The most abu
Laboratory based surveillance of travel-related Shigella sonnei and Shigella flexneri in Alberta from 2002 to 2007
Steven J Drews, Chris Lau, Marnie Andersen, Christina Ferrato, Kim Simmonds, Liala Stafford, Bev Fisher, Doug Everett, Marie Louie
Globalization and Health , 2010, DOI: 10.1186/1744-8603-6-20
Abstract: Shigella is a common cause of diarrheal illness in North America with a rate of 2.0 per 100,000 in Canada [1] and a rate of 3.2 per 100,000 in the United States [2,3]. Imported cases of Shigella infections have been reported in developed countries following travel to a foreign or developing country [4,5] and may be impacted by factors including socio-economic factors [6], food distribution networks [5] and microbiologic factors [7]. Across multiple geographic regions, high rates of antimicrobial resistance to multiple agents (e.g. sulfonamides, tetracycline, chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole) have limited the choices for empiric antimicrobial therapy required to manage Shigella infections and reduce fecal excretion of the bacteria [8-10] with descriptions of shifting species dominance and changes in antimicrobial susceptibility [10,11]. Generally, Shigella flexneri and Shigella sonnei are the dominant species and are heavily impacted by changes in antimicrobial susceptibility [12,13].This study identifies the global regions associated with travel-related cases of S. flexneri and S. sonnei in Alberta, Canada and compares antibiotic resistance patterns of these isolates for 2002 to 2007 inclusive.Specimens collected 2002-2007 (inclusive) from S. flexneri and S. sonnei infections in Alberta, Canada were included for study. Data collected at time of specimen submission included: date of specimen collection, outbreak association if present, travel history and antibiogram (data source-ProvLab Information Systems; Communicable Disease Report at Alberta Health and Wellness). Outbreaks were defined by public health officials as ≥ 2 epidemiologically related cases. Each outbreak was assigned a unique incident number. Repeat isolates received within six months of original case infections were excluded. Only one representative case for each outbreak was included, unless the isolates had different antibiotic susceptibility patterns. Based on travel h
Epidemiological characterization of resistance and PCR typing of Shigella flexneri and Shigella sonnei strains isolated from bacillary dysentery cases in Southeast Brazil
Penatti, M.P.A.;Hollanda, L.M.;Nakazato, G.;Campos, T.A.;Lancellotti, M.;Angellini, M.;Brocchi, M.;Rocha, M.M.M.;Silveira, W. Dias da;
Brazilian Journal of Medical and Biological Research , 2007, DOI: 10.1590/S0100-879X2006005000069
Abstract: shigella spp are gram-negative, anaerobic facultative, non-motile, and non-sporulated bacilli of the enterobacteriaceae family responsible for "shigellosis" or bacillary dysentery, an important cause of worldwide morbidity and mortality. however, despite this, there are very few epidemiological studies about this bacterium in brazil. we studied the antibiotic resistance profiles and the clonal structure of 60 shigella strains (30 s. flexneri and 30 s. sonnei) isolated from shigellosis cases in different cities within the metropolitan area of campinas, state of s?o paulo, brazil. we used the following well-characterized molecular techniques: enterobacterial repetitive intergenic consensus, repetitive extragenic palindromic, and double-repetitive element-polymerase chain reaction to characterize the bacteria. also, the antibiotic resistance of the strains was determined by the diffusion disk method. many strains of s. flexneri and s. sonnei were found to be multi-resistant. s. flexneri strains were resistant to ampicillin in 83.3% of cases, chloramphenicol in 70.0%, streptomycin in 86.7%, sulfamethoxazole in 80.0%, and tetracycline in 80.0%, while a smaller number of strains were resistant to cephalothin (3.3%) and sulfazotrim (10.0%). s. sonnei strains were mainly resistant to sulfamethoxazole (100.0%) and tetracycline (96.7%) and, to a lesser extent, to ampicillin (6.7%) and streptomycin (26.7%). polymerase chain reaction-based typing supported the existence of specific clones responsible for the shigellosis cases in the different cities and there was evidence of transmission between cities. this clonal structure would probably be the result of selection for virulence and resistance phenotypes. these data indicate that the human sanitary conditions of the cities investigated should be improved.
Changing Trends in the Prevalence of Shigella Species: Emergence of Multi-Drug Resistant Shigella sonnei Biotype g in Bangladesh  [PDF]
Abu I. M. S. Ud-Din, Syeda U. H. Wahid, Hasan A. Latif, Mohammad Shahnaij, Mahmuda Akter, Ishrat J. Azmi, Trisheeta N. Hasan, Dilruba Ahmed, Mohammad A. Hossain, Abu S. G. Faruque, Shah M. Faruque, Kaisar A. Talukder
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0082601
Abstract: Shigellosis, caused by Shigella species, is a major public health problem in Bangladesh. To determine the prevalence and distribution of different Shigella species, we analyzed 10,827 Shigella isolates from patients between 2001 and 2011. S. flexneri was the predominant species isolated throughout the period. However, the prevalence of S. flexneri decreased from 65.7% in 2001 to 47% in 2011, whereas the prevalence of S. sonnei increased from 7.2% in 2001 to 25% in 2011. S. boydii and S. dysenteriae accounted for 17.3% and 7.7% of the isolates respectively throughout the period. Of 200 randomly selected S. sonnei isolates for extensive characterization, biotype g strains were predominant (95%) followed by biotype a (5%). Resistance to commonly used antibiotics including trimethoprim-sulfamethoxazole, nalidixic acid, ciprofloxacin, mecillinam and ampicillin was 89.5%, 86.5%, 17%, 10.5%, and 9.5%, respectively. All isolates were susceptible to ceftriaxone, cefotaxime, ceftazidime and imipenem. Ninety-eight percent of the strains had integrons belonging to class 1, 2 or both. The class 1 integron contained only dfrA5 gene, whereas among class 2 integron, 16% contained dhfrAI-sat1-aadA1-orfX gene cassettes and 84% harbored dhfrA1-sat2 gene cassettes. Plasmids of ~5, ~1.8 and ~1.4 MDa in size were found in 92% of the strains, whereas only 33% of the strains carried the 120 MDa plasmid. PFGE analysis showed that strains having different integron patterns belonged to different clusters. These results show a changing trend in the prevalence of Shigella species with the emergence of multidrug resistant S. sonnei. Although S. flexneri continues to be the predominant species albeit with reduced prevalence, S. sonnei has emerged as the second most prevalent species replacing the earlier dominance by S. boydii and S. dysenteriae in Bangladesh.
Construction of Stable and Non-resistant Bivalent Vaccine Candidate Strain Against Shigella flexneri 2a and Shigella sonnei

Rui Xianliang Xu Yongqiang Wang Hong Su Guofu Huang Cuifen,

生物工程学报 , 1996,
Abstract: The E. coli cs3 gene coding for CFA/11 antigen was site-specifically integrated into the asd gene locus of S. flexneri 2a vaccine strain T32, resulting in the asd gene inactivated. Meanwhile, the S. sonnei O antigen gene was cloned into a non-resistant expression vector pXL378 to construct the plasmid pXL390. By transforming the asd minus T32 strain with pXL390, the bivalent vaccine candidate strain FS01 against S. flexneri 2a and S. sonnei was finally obtained. Experiments showed that the recombinant plasmid pXL390 was very stable in the asd minus T32 strain without the use of any antibiotics; FS01 strain was genetically stable and expressed two kinds of Shigella LPS-O antigens with no enhancement of its toxicity. Animal test demonstrated that FS01 strain, when administered subcutaneously in mice,could confer 100% protection against the intraperi-toneal challenges of virulent S. flexneri 2a and S. sonnei.
Rapid Diagnosis of Diarrhea Caused by Shigella sonnei Using Dipsticks; Comparison of Rectal Swabs, Direct Stool and Stool Culture  [PDF]
Claudia Duran, Faridabano Nato, Sylvie Dartevelle, Lan Nguyen Thi Phuong, Neelam Taneja, Marie No?lle Ungeheuer, Guillermo Soza, Leslie Anderson, Dona Benadof, Agustín Zamorano, Tai The Diep, Truong Quang Nguyen, Vu Hoang Nguyen, Catherine Ottone, Evelyne Bégaud, Sapna Pahil, Valeria Prado, Philippe Sansonetti, Yves Germani
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0080267
Abstract: Background We evaluated a dipstick test for rapid detection of Shigella sonnei on bacterial colonies, directly on stools and from rectal swabs because in actual field situations, most pathologic specimens for diagnosis correspond to stool samples or rectal swabs. Methodology/Principal Findings The test is based on the detection of S. sonnei lipopolysaccharide (LPS) O-side chains using phase I-specific monoclonal antibodies coupled to gold particles, and displayed on a one-step immunochromatographic dipstick. A concentration as low as 5 ng/ml of LPS was detected in distilled water and in reconstituted stools in 6 minutes. This is the optimal time for lecture to avoid errors of interpretation. In distilled water and in reconstituted stools, an unequivocal positive reaction was obtained with 4 x 106 CFU/ml of S. sonnei. The specificity was 100% when tested with a battery of Shigella and different unrelated strains. When tested on 342 rectal swabs in Chile, specificity (281/295) was 95.3% (95% CI: 92.9% - 97.7%) and sensitivity (47/47) was 100%. Stool cultures and the immunochromatographic test showed concordant results in 95.5 % of cases (328/342) in comparative studies. Positive and negative predictive values were 77% (95% CI: 65% - 86.5%) and 100% respectively. When tested on 219 stools in Chile, Vietnam, India and France, specificity (190/198) was 96% (95% CI 92%–98%) and sensitivity (21/21) was 100%. Stool cultures and the immunochromatographic test showed concordant results in 96.3 % of cases (211/219) in comparative studies. Positive and negative predictive values were 72.4% (95% CI 56.1%–88.6%) and 100 %, respectively. Conclusion This one-step dipstick test performed well for diagnosis of S. sonnei both on stools and on rectal swabs. These data confirm a preliminary study done in Chile.
Topological characterisation and identification of critical domains within glucosyltransferase IV (GtrIV) of Shigella flexneri
Anesh Nair, Haralambos Korres, Naresh K Verma
BMC Biochemistry , 2011, DOI: 10.1186/1471-2091-12-67
Abstract: In this study, the topology of GtrIV was experimentally determined by creating different fusions between GtrIV and a dual-reporter protein, PhoA/LacZ. This study shows that GtrIV consists of 8 transmembrane helices, 2 large periplasmic loops, 2 small cytoplasmic N- and C- terminal ends and a re-entrant loop that occurs between transmembrane helices III and IV. Though this topology differs from that of GtrI, GtrII, GtrV and GtrX, it is very similar to that of GtrIc. Furthermore, both the N-terminal periplasmic and the C-terminal periplasmic loops are important for GtrIV function as shown via a series of loop deletion experiments and the creation of chimeric proteins between GtrIV and its closest structural homologue, GtrIc.The current study provides the basis for elucidating the structure and mechanism of action of this important O-antigen modifying glucosyltransferase.Shigellosis, or bacillary dysentery, is caused by members of the genus Shigella. This genus belongs to the Gram-negative bacterial family Enterobacteriaceae, and is divided into 4 species: S. flexneri, S. dysenteriae, S. boydii, and S. sonnei, all of which cause shigellosis. Shigella flexneri, the species responsible for the highest mortality rate, is endemic in most developing countries. There are 15 known S. flexneri serotypes, which differ in their virulence, prevalence, distribution and O-antigens [1,2]. The O-antigen is the distal capping moiety of the bacteriallipopolysaccharide (LPS), a molecule that extends from the bacterial surface. The O-antigen backbone consists of repeating units of the tetrasaccharide N-acetylglucosamine-rhamnose I-rhamnose II-rhamnose III [3]. This basic backbone, serotype Y, is present in all serotypes except serotype 6 and 6a. The addition of glucosyl and/or O-acetyl groups to different sugars in the tetrasaccharide unit by one of several linkages gives rise to different serotypes. Glucosylation can occur in any one of the four residues that are present in the tetrasac
Increasing Antimicrobial Resistance among Shigella Isolates in the Bushehr, Iran  [PDF]
O. Gharibi,S. Zangene,N. Mohammadi,K. Mirzaei
Pakistan Journal of Biological Sciences , 2012,
Abstract: Antibiotics are drugs used for treatment of infections caused by bacteria. Misuse and overuse of these drugs have contributed to phenomena known as antibiotic resistance. In this research, the antimicrobial resistance of the Shigella has been determined. This descriptive research analyzed registered laboratory data of patients referred to Fatemeh Zahra Hospital of the Bushehr, Iran. Shigella was isolated from their cultured sample from the year 2002-2008. In this study, the total of 121 registered Shigella collected from 2002-2008 were analyzed. There were 62 cases of S. sonnei, 46 cases of S. flexneri, eight cases of S. boydii and five cases of S. dysenteriae among them. Furthermore, two cases of Shigella sonnei were collected from the blood and the rest from the watery stools of the infected patients. The following is the resistance pattern of these organisms; to ciprofloxacin, 4.25%; ceftizoxime, 8.62%; nalidixic acid, 12.12%; co-trimoxazole, 86.13% and to tetracycline, 93.02%. Results of antibiogram showed that highest rate of drug resistance belongs to tetracycline and Co-trimoxazole and the lowest belongs to ciprofloxacin and ceftizoxime. One of the important issue for clinicians, now a day is drug resistance of microorganisms. This phenomenon is increasing due to some factors such as improper use of antibiotics and irrational prescribing. These factors lead to development of new drug resistant species.
The Rising Dominance of Shigella sonnei: An Intercontinental Shift in the Etiology of Bacillary Dysentery  [PDF]
Corinne N. Thompson?,Pham Thanh Duy?,Stephen Baker
PLOS Neglected Tropical Diseases , 2015, DOI: 10.1371/journal.pntd.0003708
Abstract: Shigellosis is the major global cause of dysentery. Shigella sonnei, which has historically been more commonly isolated in developed countries, is undergoing an unprecedented expansion across industrializing regions in Asia, Latin America, and the Middle East. The precise reasons underpinning the epidemiological distribution of the various Shigella species and this global surge in S. sonnei are unclear but may be due to three major environmental pressures. First, natural passive immunization with the bacterium Plesiomonas shigelloides is hypothesized to protect populations with poor water supplies against S. sonnei. Improving the quality of drinking water supplies would, therefore, result in a reduction in P. shigelloides exposure and a subsequent reduction in environmental immunization against S. sonnei. Secondly, the ubiquitous amoeba species Acanthamoeba castellanii has been shown to phagocytize S. sonnei efficiently and symbiotically, thus allowing the bacteria access to a protected niche in which to withstand chlorination and other harsh environmental conditions in temperate countries. Finally, S. sonnei has emerged from Europe and begun to spread globally only relatively recently. A strong selective pressure from localized antimicrobial use additionally appears to have had a dramatic impact on the evolution of the S. sonnei population. We hypothesize that S. sonnei, which exhibits an exceptional ability to acquire antimicrobial resistance genes from commensal and pathogenic bacteria, has a competitive advantage over S. flexneri, particularly in areas with poorly regulated antimicrobial use. Continuing improvement in the quality of global drinking water supplies alongside the rapid development of antimicrobial resistance predicts the burden and international distribution of S. sonnei will only continue to grow. An effective vaccine against S. sonnei is overdue and may become one of our only weapons against this increasingly dominant and problematic gastrointestinal pathogen.
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