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The prevalence and antimicrobial responses of Shigella isolates in HIV-1 infected and uninfected adult diarrhoea patients in north west Ethiopia
B Andualem, A Kassu, E Diro, F Moges, M Gedefaw
Ethiopian Journal of Health Development , 2006,
Abstract: Background: Shigella is one of the diarrhoea causing organisms found in HIV positive patients. But so far, the pattern of diarrhoeal agents caused by Shigella in AIDS patients has not been determined. Objective: This study is thus aimed at determining the prevalence, antimicrobial susceptibility and resistance of Shigella isolates in HIV positive subjects. Methods: All stool samples taken from the subjects of this study were plated on the MacConkey agar and incubated at 35-37oC for 24 or 48 hrs. Biochemical and antimicrobial sensitivity testing were carried out by using the standard methods. Results: Out of the 391 subjects included in the study, 199(63.8%) HIV seropositive and 113 seronegative patients had acute and chronic diarrhoea while 79 were HIV seropositive without diarrhoea. Of the 27 (8.7) Shigella isolates taken from the diarrhea patients, 11 (3.5%) were from HIV positive subjects. All Shigella isolates were found to be sensitive against norfloxacin (100%), gentamicin (97%), polymyxin B (97%) and kanamycin (93%). The most frequent resistance observed was to chloramphenicol (62%), tetracycline (86%) and ampicillin (100%). The frequency of resistance of Amp, Sex, Ch, TTc was found to be very high when compared with other patterns of resistance. Conclusion: The high proportion of HIV seropositive patients who had diarrhea in the absence of identified Shigella strains strongly indicates the existence of other diarrhoeagenic agents or mechanisms. Detailed investigation is important to get comprehensive information for better treatment of diarrhoea in HIV /AIDS patients. According to this finding, norfloxacin, gentamicin, polymyxin B, kanamycin and nalidixic acid might be used as drugs of choice for empirical treatment. On the other hand, amplicilin, tetracycline and chloramphenicol may not be used as the drugs of choice for the treatment of Shigella infection unless culture and sensitivity tests are done prior to treatment. The Ethiopian Journal of Health Development Vol. 20 (2) 2006: 99-105
Detection of virulence genes in Malaysian Shigella species by multiplex PCR assay
Kwai Thong, Susan Hoe, SD Puthucheary, Rohani Md Yasin
BMC Infectious Diseases , 2005, DOI: 10.1186/1471-2334-5-8
Abstract: A mPCR assay was designed for the simultaneous detection of chromosomal- and plasmid-encoded virulence genes (set1A, set1B, ial and ipaH) in Shigella spp. One hundred and ten Malaysian strains (1997–2000) isolated from patients from various government hospitals were used. Reproducibility and sensitivity of the assay were also evaluated. Applicability of the mPCR in clinical settings was tested with spiked faeces following preincubation in brain heart infusion (BHI) broth.The ipaH sequence was present in all the strains, while each of the set1A, set1B and ial gene was present in 40% of the strains tested. Reproducibility of the mPCR assay was 100% and none of the non-Shigella pathogens tested in this study were amplified. The mPCR could detect 100 colony-forming units (cfu) of shigellae per reaction mixture in spiked faeces following preincubation.The mPCR system is reproducible, sensitive and is able to identify pathogenic strains of shigellae irrespective of the locality of the virulence genes. It can be easily performed with a high throughput to give a presumptive identification of the causal pathogen.Members of the genus Shigella, namely S. flexneri, S. dysenteriae, S. sonnei and S. boydii have caused and continue to be responsible for mortality and/or morbidity in high risk populations such as children under five years of age, senior citizens, toddlers in day-care centres, patients in custodial institutions, homosexual men and, war- and famine-engulfed people. Yearly episodes of shigellosis globally have been estimated to be 164.7 million and of these, 163.2 million were in developing countries and the remaining in industrialized nations. The mortality rate was approximately 0.7% [1]. A recent study by Lee & Puthucheary [2] on bacterial enteropathogens in childhood diarrhoea in a Malaysian urban hospital showed that Shigella spp. was the third most common bacteria isolated. S. flexneri and S. dysenteriae type 1 infections are usually characterized by frequent pa
Mechanism of antimicrobial resistance in Shigella isolates  [PDF]
S Mehata,GC Duan,WD Zhang
International Journal of Infection and Microbiology , 2012, DOI: 10.3126/ijim.v1i2.7406
Abstract: INTRODUCTION: Shigellosis still remains a public health problem in developing countries because of poverty, poor sanitation, personal hygiene and poor water supply. Antimicrobial therapy for shigellosis reduces the duration and severity of the disease and can also prevent potentially lethal complications. However, over the past few decades Shigella spp. has become resistant to most of the widely used antimicrobials. This study assessed the patterns of antimicrobial susceptibility and mutations in marA and marR genes of Shigella isolates and its association. MATERIALS AND METHODS: Fifty three isolates of Shigella spp. were tested to evaluate the antimicrobial susceptibility by disc diffusion method (Kirby-Bauer) according to the Clinical Laboratory Standard Institute (CLSI) for the following antimicrobials: ciprofloxacin, norfloxacin, ampicillin, tetracycline, chloramphenicol, trimethoprim, gentamicin and streptomycin and mutation on marAR genes by using polymerase chain reaction–Single strand conformation polymorphism analysis. RESULTS: Study revealed that there was significant association in between resistant to ciprofloxacin, norfloxacin and gentamicin with mutation in marA gene (87.5% vs 51.1%, P<0.05; 87.5%Vs 51.1%, P<0.05 and 90% vs 48.8%, P<0.05, respectively). However, there was no significant association in between resistant to tetracycline, streptocycin and ampicillin. Similarly, it was noted that the association in between antimicrobial resistance with mutation in marR like ciprofloxacin (O% vs 57.8%, P<0.05); norfloxacin (O% vs 57.8%, P<0.05), chloramphenicol (O% vs 70.3%, P<0.05); gentamicin (O% vs 60.5%, P<0.05) and trimethoprim (42.6% vs 100%, P<0.05), suggest that mutation in marR is protective factor for antimicrobial resistance. CONCLUSIONS: The study revealed that mutation in marR is preventive factors for antimicrobial resistance like ciprofloxacin, norfloxacin, chloramphenicol, gentamicin and trimethoprim. DOI: http://dx.doi.org/10.3126/ijim.v1i2.7406 Int J Infect Microbiol 2012;1(1):43-48
Antimicrobial susceptibility pattern of Shigella isolates in Awassa
Belay Roma, Solomon Worku, Shiferaw T Mariam, Nina Langeland
Ethiopian Journal of Health Development , 2000,
Abstract: A prospective study was conducted in Awassa, Southern Ethiopia from July 1997 to April 1998 in order to determine the antimicrobial pattern of Shigella strains. Moreover, the study was intended to form the basis of treatment guidelines for shigellosis appropriate to local conditions. In addition, the study was designed to accumulate epidemiological information on the resistance patterns of Shigella isolates of public health importance. A total of one hundred Shigella strains were isolated from 289 cultures received at the Center for Health Research and Laboratories (CHRL), collected from different health units. Ninety-nine strains were Shigella flexneri group B and one Shigella dysenteriae group A isolated. All isolates were susceptibility tested for nine antibiotics using disc diffusion technique. The result showed that 96% and 90% strains were susceptible to gentamicin and nalidixic acid respectively. High rate of resistance was particularly documented against the following antibiotics: ampicillin (93%), erythromycin (90%), and tetracycline (90%). Fifty-six percent of Shigella flexneri Group B isolates were found to be resistant to trimethoprim-sulfamethoxazole, which is one of the drugs of choice for treating shigellosis is Ethiopia. Multiple drug resistance to as many as six antibiotics, i.e. ampicillin, cephalotin, chloramphenicol, erythromycin, tetracycline and trimethoprim-sulfamethoxazole has been observed in this study. One strain of Shigella flexneri was found to be resistant to eight drugs. The findings are discussed and recommendations forwarded. (Ethiopian Journal of Health Development, 2000, 14(2): 149-154)
Frequency of serovars and antimicrobial resistance in Shigella spp. from Brazil
Peirano, Gisele;Souza, Flávia dos Santos;Rodrigues, Dalia dos Prazeres;,;
Memórias do Instituto Oswaldo Cruz , 2006, DOI: 10.1590/S0074-02762006000300003
Abstract: a total of 296 shigella spp. were received from state public health laboratories, during the period from 1999 to 2004, by national reference laboratory for cholera and enteric diseases (nrlced) - ioc/fiocruz, rio de janeiro, brazil. the frequency of shigella spp. was: s. flexneri (52.7%), s. sonnei (44.2%), s. boydii (2.3%), and s. dysenteriae (0.6%). the most frequent s. flexneri serovars were 2a and 1b. the highest incidence rates of shigella isolation were observed in the southeast (39%) and northeast (34%) regions and the lowest rate in the south (3%) of brazil. strains were further analyzed for antimicrobial susceptibility by disk diffusion method as part of a surveillance program on antimicrobial resistance. the highest rates of antimicrobial resistance were to trimethoprim-sulfamethozaxole (90%), tetracycline (88%), ampicillin (56%), and chloramphenicol (35%). the patterns of antimicrobial resistance among shigella isolates pose a major difficulty in the determination of an appropriate drug for shigellosis treatment. continuous monitoring of antimicrobial susceptibilities of shigella spp. through a surveillance system is thus essential for effective therapy and control measures against shigellosis.
Antimicrobial Resistance of Shigella from Patients with Acute Diarrhea. Quaemshahr, Mazandaran, Iran
N. Najafi,R. Ghasemian,M. Shariatzadeh,S. Alian
Research Journal of Biological Sciences , 2012,
Abstract: This study was performed to determine the pattern of antimicrobial resistance of Shigella sp. in patients with acute diarrhea. The study included all patients with acute diarrhea who were visited in a teaching hospital during 14 months period (2004- 2005). The isolates were confirmed by biochemical reaction and specific antisera. Antibiotic susceptibility test was determined by agar diffusion method. Of the 273 stool samples, 130(47.6%) yielded Shigella sp. Shigella flexneri caused 94(72.3%) of the total cases of shigellosis followed by S. dysenteriae 17 (13.1%), S. boydii 15 (11.5%) and S. sonnei 4 (3.1%). All 130 isolates showed resistance at least to one of eleven antibiotics and 123/130 (94.6%) were resistant to two or more antimicrobial agents. The high number of multi-drug resistance isolates and decreased susceptibility to main antibiotics for treatment of Shigella sp. warrant need to continuous monitoring of antimicrobial susceptibilities through a surveillance system for effective therapy and control measures.
A Multicentre Study of Shigella Diarrhoea in Six Asian Countries: Disease Burden, Clinical Manifestations, and Microbiology  [PDF]
Lorenz von Seidlein ,Deok Ryun Kim,Mohammad Ali,Hyejon Lee,XuanYi Wang,Vu Dinh Thiem,Do Gia Canh,Wanpen Chaicumpa,Magdarina D Agtini,Anowar Hossain,Zulfiqar A Bhutta,Carl Mason,Ornthipa Sethabutr,Kaisar Talukder,G. B Nair,Jacqueline L Deen,Karen Kotloff,John Clemens
PLOS Medicine , 2006, DOI: 10.1371/journal.pmed.0030353
Abstract: Background The burden of shigellosis is greatest in resource-poor countries. Although this diarrheal disease has been thought to cause considerable morbidity and mortality in excess of 1,000,000 deaths globally per year, little recent data are available to guide intervention strategies in Asia. We conducted a prospective, population-based study in six Asian countries to gain a better understanding of the current disease burden, clinical manifestations, and microbiology of shigellosis in Asia. Methods and Findings Over 600,000 persons of all ages residing in Bangladesh, China, Pakistan, Indonesia, Vietnam, and Thailand were included in the surveillance. Shigella was isolated from 2,927 (5%) of 56,958 diarrhoea episodes detected between 2000 and 2004. The overall incidence of treated shigellosis was 2.1 episodes per 1,000 residents per year in all ages and 13.2/1,000/y in children under 60 months old. Shigellosis incidence increased after age 40 years. S. flexneri was the most frequently isolated Shigella species (1,976/2,927 [68%]) in all sites except in Thailand, where S. sonnei was most frequently detected (124/146 [85%]). S. flexneri serotypes were highly heterogeneous in their distribution from site to site, and even from year to year. PCR detected ipaH, the gene encoding invasion plasmid antigen H in 33% of a sample of culture-negative stool specimens. The majority of S. flexneri isolates in each site were resistant to amoxicillin and cotrimoxazole. Ciprofloxacin-resistant S. flexneri isolates were identified in China (18/305 [6%]), Pakistan (8/242 [3%]), and Vietnam (5/282 [2%]). Conclusions Shigella appears to be more ubiquitous in Asian impoverished populations than previously thought, and antibiotic-resistant strains of different species and serotypes have emerged. Focusing on prevention of shigellosis could exert an immediate benefit first by substantially reducing the overall diarrhoea burden in the region and second by preventing the spread of panresistant Shigella strains. The heterogeneous distribution of Shigella species and serotypes suggest that multivalent or cross-protective Shigella vaccines will be needed to prevent shigellosis in Asia.
The Effect of the Potential PhoQ Histidine Kinase Inhibitors on Shigella flexneri Virulence  [PDF]
Xia Cai, Jian Zhang, Mingliang Chen, Yang Wu, Xueqing Wang, Jiayu Chen, Junqin Zhang, Xu Shen, Di Qu, Hualiang Jiang
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023100
Abstract: PhoQ/PhoP is an important two-component system that regulates Shigella virulence. We explored whether the PhoQ/PhoP system is a promising target for new antibiotics against S. flexneri infection. By using a high-throughput screen and enzymatic activity coupled assay, four compounds were found as potential PhoQ inhibitors. These compounds not only inhibited the activity of SF-PhoQc autophosphorylation but also displayed high binding affinities to the SF-PhoQc protein in the Surface Plasmon Resonance response. A S. flexneri cell invasion assay showed that three of these potential PhoQ inhibitors inhibit the invasion of HeLa cells by S. flexneri 9380. In a Mouse Sereny test, mice inoculated with S. flexneri 9380 pre-treated with the potential PhoQ inhibitors 1, 2, 3 or 4 displayed no inflammation, whereas mice inoculated with S. flexneri 9380 alone displayed severe keratoconjunctival inflammation. All four potential PhoQ inhibitors showed no significant cytotoxicity or hemolytic activity. These data suggest that the four potential PhoQ inhibitors inhibited the virulence of S. flexneri and that PhoQ/PhoP is a promising target for the development of drugs against S. flexneri infection.
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.
Characterization of Shigella spp. by antimicrobial resistance and PCR detection of ipa genes in an infantile population from Porto Velho (Western Amazon region), Brazil
Silva, Tatiane;Nogueira, Paulo Afonso;Magalh?es, Gleiciene Félix;Grava, Andréa Fagundes;Silva, Luiz Hildebrando Pereira da;Orlandi, Patrícia Puccinelli;
Memórias do Instituto Oswaldo Cruz , 2008, DOI: 10.1590/S0074-02762008000700017
Abstract: the incidence of shigella spp. was assessed in 877 infants from the public hospital in rond?nia (western amazon region, brazil) where shigella represents the fourth cause of diarrhea. twenty-five isolates were identified: 18 were shigella flexneri, three shigella sonnei, three shigella boydii and one shigella dysenteriae. with the exception of s. dysenteriae, all shigella spp. isolated from children with diarrhea acquired multiple antibiotic resistances. pcr detection of ipa virulence genes and invasion assays of bloody diarrhea and fever (colitis) were compared among 25 patients testing positive for shigella. the ipah and ipabcd genes were detected in almost all isolates and, unsurprisingly, all shigella isolates associated with colitis were able to invade hela cells. this work alerts for multiple antibiotic resistant shigella in the region and characterizes presence of ipa virulence genes and invasion phenotypesin dysenteric shigellosis.
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