Determining minimum inhibitory concentration growth rate and sensitivity of Yersinia to beta-lactam antibiotics

Background: Diarrhea is one of the most important causes of children mortality in developing countries. Gastroenteritis causes mortality in children younger than five years old annually. The presence of antibiotics resistance species among these bacteria are major health problems. Objective: This study aimed to determine the antibiotic susceptibility and MIC50%, MIC90% of Yersinia to three beta-lactam antibiotics. Methods: This experimental study was determined sensitivity of different species of Yersinia to three beta-lactam antibiotics (Ampicillin-Cefazolin Cefotaxime ). In total 50 species (39 from different human sources, environments, foods and 11 from Pasteur institutions in Paris) were used. Minimum inhibitory concentration (MIC) was carried out by serial dilution method. Findings: Among three tested antibiotics, the lowest MIC 50%, MIC 90% were obtained for Cefotaxime (≤0.125μg/ml and 0.5μg/ml). All the tested species showed resistance to Ampicillin and very low sensitivity toward Cefazolin. Conclusion: The results showed that Cefotaxime was more effective against Yersinia species in compared to Ampicillin and Cefazolin. Keywords: Yersinia spp, Beta lactam, minimum inhibitory concentration (MIC), Ampicillin, Cefazolin, Cefotaxim

Prevalence of Yersinia Enterocolitis in pediatric dysentery

Yersinia enterocolitis causes a wide spectrum of human diseases including gasteroentritis, which is the most frequent of its manifestation. Other diseases and clinical syndromes resulting from Yersinia enterocolitica are septicemia, mesenteric lymphadenitis, apendisitis, exudative pharyngitis, reactive artiritis, nodosum erythema and rarely Reiter's syndrome. In many countries such as western European, Scandinavian and north American countries, Australia and Japan the role of Yersinia enterocolitica particularly the 0:3, 0:8 and 0:9 serotypes in human diseases have been clearly identified. In spite of significant development in the field of separating Yersinia enterocolitica from feces as well as from the environmental specimens during the last decade, there has been only one documented report of isolating Yersinia enterocolitica in Iran in 1977. Thus we decided to test 300 samples of feces within 5 months. In this method, CIN agar as a selective and special medium and Mac conkey agar as classic medium were used. Also cold enrichment method in PBS (pH=7.8) was used. In order to determine importance of enterocolitica, we separated other pathogens of intestine such as salmonella, shigella and entropathogenic E.Coli. The achieved results from abundance points of view are as follows: 17 strains of EPEC (5.66%), 9 strains of shigella (3%), 8 strains of Yersinia enterocolitica (2.66%) and 6 strains of salmonella (2%

Evaluation of anti-microbial activity of Lactobacillus acidophillus and Lactobacillus ruteri against entero-pathoges by in vitro and in vivo methods

Background and Objective: Probiotics are beneficial organisms therapeutic within microbial flora. Shigella, Escherichia coli and Salmonella are the most common cause of intestinal infectious diseases that lead to morbidity and mortality in infant and children worldwide. The aim of this study was to evaluate anti-microbial activity of Lactobacillus acidophillus and Lactobacillus ruteri against entero-pathoges by in vitro and in vivo methods. Methods: In this experimental study, the therapeutic effect of the lactobacillus acidophilus ATCC 4356 and ruteri ATCC 23272 against Shigella sonnei ATCC 9290, Escherichia coli ATCC 25922 and Salmonella enterica BAA-708 were evaluated by in vitro (spot agar) and in vivo (BALB/c mice) methods. Weight improvment and survival rate in mice were recorded. Results: Lactobacillus acidophillus and ruteri had protective and therapeutic effect against diarrhea caused by pathogenic bacteria. Probiotics reduced the weight, colonization of pathogens and increased the survival rate of animals (P<0.05). Conclusion: Lactobacillus acidophillus and ruteri has anti-microbial activity and their consumption can be effective in the prevention and also the treatment of intestinal disease

Serogroup Distribution of Shigella in Tehran

In recent years, the importance of Shigella as an enteric pathogen with global impact has been increasingly recognized. In this study, serogroup distribution of Shigella isolated from clinically diagnosed cases of gastroenteritis and acute diarrhea in Tehran, capital of Iran was investigated between December 2002 and November 2003. Fecal specimens and rectal swabs were cultured for Shigella spp. using standard microbiological techniques. The isolates of Shigella were identified by biochemical assay and serological testing. From a total of 302 Shigella isolates, 178, 110, 10 and 4 strains were identified as S.sonnei (58.9%; 95% CI: 53.2-64.5), S. flexneri (36.4%; 95% CI: 31.0-42.2), S.boydii (3.3%), and S. dysenteriae (1.3%), respectively. The peak of infection occurred during summer. Overall, 167 patients (55.3%) were males and 135 (44.7%) were female

Detection of E.Coli Strains Containing Shiga Toxin (Stx1/2) Gene in Diarrheal Specimens from Children Less than 5 Years Old by PCR Technique and Study of the Patterns of Antibiotic Resistance

Introduction: Shiga toxin- producing Escherichia coli (STEC) is an emerging bacterial pathogen in developing countries that causes several diseases such as diarrhea, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS), particularly in children. Aim of the research was detection of STEC in diarrheal specimens from under 5 year olds and study of the patterns of antibiotic resistance of these strains. Methods: In the study,300 fecal samples were collected from children with diarrhea referring to Ali Asghar Hospital. E.coli species were isolated by standard bacteriological and biochemical tests. Presence of shiga toxin genes (stx1/2) was investigated by PCR technique (Qiagen). Antibiogram test for strains containing the toxin gene was performed using 16 different antibiotic discs (MAST) by disc diffusion agar (Kirby-Bauer) method. Results: From 39 E.coli isolates, 9(23.1%) strains were detected by PCR to contain stx1/2 gene. One strain was resistant to all 16 antibiotics. All the STEC strains were sensitive to meropenem (MRP), imipenem (IMI), gentamycin (GEN) and nitrofurantoin (NI). 4(44.44%) strains showed multi-drug resistant pattern. All these 4strains were resistant to cotrimoxazole(SxT). Also, 6(66.66%) strains were resistant to at least one antibiotic. Conclusion: In Iran, shiga toxin- producing Escherichia coli (STEC) may be a commonly bacterial pathogen causing diarrhea, particularly in children. Therefore, we should use new techniques for investigation of these strains. Increase in number of emerging and new strains that could be resistant to classic antibiotics such as cotrimoxazole may be foreseen. It is suggested that antibiotics prescription programs in treatment of diarrhea causing E.coli strains be updated

The importance of inducible clindamycin resistance in enterotoxin positive S. aureus isolated from clinical samples

&quot;nBackground: Clindamycin is a suitable antibiotic for treatment of skin and soft tissue infections. Moreover, it can suppress toxin production in many pathogenic bacteria such as S. aureus. There are two mechanisms of resistance in this antibiotic. Constitutive resistance can be detected by standard disk diffusion method but in the case of inducible resistance, D-test should be carried out. The main aim of this study is to determine prevalence of clindamycin inducible resistance among methicillin resistant and susceptible isolates of S. aureus isolated from different clinical samples. &quot;nMethods: A total of 87 clinical isolates from clinical samples were collected. Methicillin resistance was determined using standard disk diffusion method. Subsequently, D-test was carried out according to CLSI guideline. Presence of the sea gene (enterotoxin A) was detected by PCR using specific primers. &quot;nResults: Out of 87 isolates, 18(20.7%) were clindamycin inducible resistant while constitutive resistance was detected among 21(24.1%) isolates. The 95% Confidence intervals for the proportion of inducible clindamycin resistance among clinical isolates of S. aureus was 12.2% to 29.2%. The inducible phenotype in MRSA isolates was more common than that of MSSA isolates (33.3% vs 5.1%).Significant differences were found between prevalence of inducible clindamycin resistance and type of infection (p=0.045). Importantly, there was a significant correlation between sea gene and the constitutive/inducible resistance (p&amp;lt;0.0001). &quot;nConclusions: Due to the high prevalence of clindamycin inducible resistance among clinical isolates of S. aureus, we recommend D-test to avoid treatment failure