Molecular typing of cytotoxin-producing Klebsiella oxytoca isolates by 16S-23S internal transcribed spacer PCR.

Cytotoxin is one of the important pathogenic factors, which plays a role in the virulence of Klebsiella oxytoca. The aim of this study was to investigate molecular typing of clinical isolates of the cytotoxin-producing K. oxytoca using internal transcribed spacer (ITS) PCR. A total of 75 isolates of K. oxytoca were isolated from clinical samples; they were verified as K. oxytoca by standard microbiological tests and PCR. Production of toxin determines the cytotoxic effects on HEp-2 cells. The genetic diversity of isolates of the cytotoxin-producing K. oxytoca were defined by ITS-PCR. Of all the isolates investigated, five K. oxytoca strains isolated from stool cultures, two strains from blood samples, one strain from a wound and one strain isolated from urine had cytotoxic effects on HEp-2 cells. The ITS-PCR patterns showed genetic diversity among cytotoxin-producing isolates. The ITS-PCR method had good discriminatory power; performance of this method and interpretation of the results were easy and repeatable. Five genetic diversity patterns were identified by ITS-PCR.

Identification and characterization of probiotic lactic acid bacteria isolated from traditional persian pickled vegetables.

Background: The pickle, a traditional fermented product, is popular among Iranians. Much research has been conducted worldwide on this food group. Due to a lack of related data in Iran, this study was conducted to isolate and identify dominant lactic acid bacteria (LAB) in pickles and salted pickles. Materials and methods: Seventy samples were collected from different regions of Iran. The isolated bacteria were identified as LAB by Gram staining and catalase by using MRS agar. Then, those strains were identified at the species level by physiological tests (e.g., gas production from glucose, arginine hydrolysis, CO2 production from glucose in MRS broth, carbohydrate fermentation) and growth at temperatures of 15°C, 30°C, and 45°C in MRS broth for 3 days. The probiotic characteristics of these bacteria were studied using acid and bile tolerance. The corresponding results were verified using PCR analyses of the 16S rDNA region. Results: 114 presumptive lactic acid bacteria (LAB) with Gram-positive and catalase-negative properties were obtained from the samples. The results revealed that all isolated bacteria were identfied as Lactobacillus (L.) plantarum, L. brevis, L. pentosus, L. casei, L. paracasei and Leuconostoc mesenteroides. The predominant LAB in these pickles was L. plantarum, which was isolated from most of the samples. Among the 114 LAB, 7 isolated species have probiotic potential. Six out of seven were recognized as L. plantarum and one remained unidentifiable by biochemical testing. PCR analysis and sequencing of the 16S rDNA region using 27f and 1522r primers showed that all of the probiotic strains were L. plantarum. Conclusion: The results of this study showed that the dominant LAB in traditional Persian pickled vegetables are L. plantarum, L. brevis, L. pentosus, L. casei, L. paracasei, and Leuconostoc mesenteroides. Moreover, L. plantarum was recognized as a probiotic species in pickled vegetables. The raw data obtained from this study can be used in the pickling industry to improve the nutritional value of products.

Inhibitory effect of Lactobacillus plantarum and Lb. fermentum isolated from the faeces of healthy infants against nonfermentative bacteria causing nosocomial infections.

Nosocomial infection constitutes a major public health problem worldwide. Increasing antibiotic resistance of pathogens associated with nosocomial infections has also become a major therapeutic challenge for physicians. Thus, development of alternative treatment protocols, such as the use of probiotics, matters. The aim of this research was to determine the antagonistic properties of Lactobacillus plantarum and Lb. fermentum isolated from the faeces of healthy infants against nonfermentative bacteria causing nosocomial infections. One hundred five samples of nosocomial infections were collected and processed for bacterial isolation and antimicrobial susceptibility testing following standard bacteriologic techniques. The antibiotic susceptibility test was performed by the disk diffusion method, and antagonistic effect of Lactobacillus strains was investigated by well diffusion method. Of 105 samples, a total of 29 bacterial strains were identified as nonfermentative bacteria, including 17 Acinetobacter baumannii and 12 Pseudomonas aeruginosa. A. baumannii showed high resistance to tested antibiotics except ampicillin/sulbactam, and P. aeruginosa showed resistance to ampicillin/sulbactam and gentamicin and sensitive to amikacin and meropenem. Lb. plantarum had antagonistic properties against both A. baumannii and P. aeruginosa strains. Lb. plantarum had considerable effects on preventing the growth of A. baumannii and P. aeruginosa strains. However, further research is needed to better understanding of these effects on P. aeruginosa.

Molecular characterization of Salmonella enterica serotype Enteritidis isolates from food and human samples by serotyping, antimicrobial resistance, plasmid profiling, (GTG)5-PCR and ERIC-PCR.

In recent years, Salmonella enterica serovar Enteritidis has been a primary cause of human salmonellosis in many countries. The major objective of this study was to investigate genetic diversity among Salmonella Enteritidis strains from different origins (food and human) by Enterobacterial Repetitive Intergenic Consensus (ERIC) -PCR, as well as to assess their plasmid profiling and antimicrobial resistance. A total of 30 Salmonella Enteritidis isolates, 15 from food samples (chicken, lamb, beef and duck meats) and 15 from clinical samples were collected in Tehran. Identification of isolates as Salmonella was confirmed by using conventional standard biochemical and serological tests. Multiplex-PCR was used for serotyping of isolates to identify Salmonella Enteritidis. Antimicrobial susceptibility testing to 16 agents founds drug resistance patterns among Salmonella Enteritidis isolates. No resistance was observed to cephalexin, ceftriaxone, ceftazidime and cefotaxime, ciprofloxacin, imipenem or meropenem, chloramphenicol and gentamicin. The highest resistance (96.7%) was observed to nitrofurantoin. Seven plasmid profiles (P1-P7) were detected, and a 68-kb plasmid was found in all isolates. Two different primers; ERIC and (GTG)5 were used for genotyping, which each produced four profiles. The majority of clinical and food isolates fell into two separate common types (CTs) with a similar percentage of 95% by ERIC-PCR. Using primer (GTG)5, 29 isolates incorporated in three CTs with 70% of isolates showing a single banding pattern. Limited genetic diversity among human and food isolates of Salmonella Enteritidis may indicate that contaminated foods were possibly the source of human salmonellosis. These results confirmed that ERIC-PCR genotyping has limited discriminatory power for Salmonella Enteritidis of different origin.

A comparison between occlusive and exposure dressing in the management of burn wound.

BACKGROUND AND AIM: Two types of dressing, occlusive and exposure dressing, are commonly used in burn units. A dressing is said to be occlusive if a moist wound surface is maintained when the dressing is in place. This study was designed to compare the effectiveness of occlusive and exposure dressing in controlling burn infections. PATIENTS AND METHODS: Two hundred patients with second-degree burns admitted to Mottahari Hospital, Tehran, Iran, over a period of 12 months from May 2012 to May 2013 were studied. They were divided into two groups of 100 each, to receive either occlusive or exposure dressing. During the first week of treatment, wound specimens were obtained by sterile swab and cultured in selective media. Demographics (age and gender), burn areas, cause of burn, length of hospital stay (LOS), type of infections and time to total healing were compared between the two groups. RESULTS: Occlusive dressing was more susceptible to microbial contamination and infections than exposure dressing. The mean duration of treatment based on epithelialization and healing in occlusive dressing was longer than for exposure dressing. The most common isolate was Pseudomonas spp., followed by Enterobacter, Escherichia coli, Staphylococcus aureus, Acinetobacter, and Klebsiella spp. CONCLUSIONS: Exposure dressing was more suitable than occlusive dressing for treating partial-thickness at our center. Pseudomonas aeruginosa was the most common organism encountered in burn infection.

Molecular epidemiology of Staphylococcus aureus in food samples based on the protein A gene polymorphic region DNA sequence.

Foodborne disease due to Staphylococcus aureus is a common and important disease worldwide. Molecular typing of S. aureus strains plays a crucial role in epidemiological studies examining the origin and performing surveillance of major infections. In this survey, we collected 913 food samples and detected 93 S. aureus isolates by using culture and biochemical tests. Subsequently, the X region of the protein A gene was amplified by the polymerase chain reaction (PCR) and amplicons were digested with HaeII and HindIII. Seven different patterns, ranging in length between 1200 and 1600 bp, showed gene polymorphism of the spa gene. The most prevalent spa types were D (20%) and C (16%) in dairy products and D (6%) and E (3%) in meat products. Consequently, 16 genotypes were obtained by HaeII digestion. Typeability of PCR - restriction fragment length polymorphism in genotyping of S. aureus strains in our study was perfect. Therefore, this method is a reliable, rapid, and powerful system in epidemiological investigations.

Frequency of Yersinia species infection in paediatric acute diarrhoea in Tehran.

This study determined the frequency of Yersinia enterocolitica infection in 300 children with acute diarrhoea aged 0-12 years who were attending a paediatric hospital in Tehran. Over the 5-month study (May-September 2002), Yersinia species and other organisms were cultured and serotyped from stool samples or swabs. Yersinia spp. were found in 8 cases (2.7%). Enteropathogenic Escherichia coli was isolated in 5.7% of cases, Shigella spp. in 3.0% and Salmonella spp. in 2.0%. None of the Y. enterocolitica belonged to the common serotypes of O:3 and O:9. Atypical Yersinia spp. (Y. intermedia and Y. frederiksenii) were isolated. All Y. enterocolitica isolates had a similar pattern of antimicrobial resistance. Yersinia spp. infections are not common in the summer months in Tehran.

Frequency of Yersinia species infection in paediatric acute diarrhoea in Tehran

This study determined the frequency of Yersinia enterocolitica infection in 300 children with acute diarrhoea aged 0-12 years who were attending a paediatric hospital in Tehran. Over the 5-month study [May-September 2002], Yersinia species and other organisms were cultured and serotyped from stool samples or swabs. Yersinia spp. were found in 8 cases [2.7%]. Enteropathogenic Escherichia coli was isolated in 5.7% of cases, Shigella spp. in 3.0% and Salmonella spp. in 2.0%. None of the Y. enterocolitica belonged to the common serotypes of O:3 and O:9. Atypical Yersinia spp. [Y. intermedia and Y. frederiksenii] were isolated. All Y. enterocolitica isolates had a similar pattern of antimicrobial resistance. Yersinia spp. infections are not common in the summer months in Tehran