Journal of School of Public Health and

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Background and Aim: Superinfection of burn wounds is a major cause of mortality and morbidity in hospital burn units. It is crucial for every burn center to determine the pattern of microbial colonization in burn wounds and the antimicrobial sensitivity profiles. This study was carried out on patients admitted to the Burn Unit of Emam Reza University Hospital, Mashhad, with the aim of verifying the pattern of microbial colonization of burn sites and determining the antimicrobial sensitivity of the isolated bacterial species.

Materials and Methods: In this study a total of 344 samples were obtained from 126 burn patients. After isolation and identification of bacteria, we used an agar diffusion method to determine sensitivity against 14 common antibiotics.

Results: Our results showed that 27.7% of the wounds were sterile at the time of the first dressing, but the rate of contamination increased with time so that only 5% of wounds were sterile by the third week Pseudomonas aeroginosa was the most frequently isolated species (31.7%). Most of bacteria were resistant to amoxicillin ciprofloxacin and imipenem emerged as the most effective antibiotics.

Conclusion: The common occurrence of gram-negative bacilli and staphylococci together with the sensitivity patterns show that we are far from eradication of wound infections, so there is an urgent need for improved infection control practices and policies.

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Background and Aim: In the last few decades co-trimoxazole, an antibacterial combination of trimethoprim and sulfamethoxazole, has been used for treatment of bacterial infections, but due to the vast usage of these drugs, resistant strains have appeared throughout the world. One of the reasons for resistance to co-trimoxazole is related to drf genes, which are responsible for trimethoprim resistance, while the sulfamethoxazole resistance is due to sulfonamide sul genes. The aim of this study was to investigate drug resistance and frequencies of resistance genes in gram-negative bacteria isolated from clinical specimens.

Materials and Methods: Clinical samples were collected from patients in Pars Hospital, Tehran, Iran, in which presence of gram-negative bacteria was confirmed by biochemical tests. Then antibiotic susceptibility tests were performed for 5 antibiotics by disk diffusion agar technic. DNA was extracted from bacteria resistant to co-trimoxazole, followed by PCR using specific primers for sul1, sul2, sul3, and drf7 genes.

Results: In the co-trimoxazole-resistant bacteria, 26%, 74%, 2% and 16% of the isolates contained sul1 gene, sul2 gene, sul3 gene and drf7 gene, respectively. Further analysis of the data showed that 51% of the isolates were resistant to gentamicin, 74% to ceftriaxone, 65% to ciprofloxacin and 3% to colistin. For resistance to trimethoprim only the drf 7 gene was used.

Conclusion: The results of this study show that in the isolates of co-trimoxazole-resistant gram-negative bacteria, the sul 2 gene has a major role in development of resistance to sulfonamides. In this study only the drf 7 gene was used to assess the resistance of trimethoprim, so we recommend to conduct studies also on other drf genes, so that the importance of each in resistance to co-trimoxazole can be determined.

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Background and Aim: Salmonella species is one of the important pathogens causing food poisoning and gastroenteritis. The aim of the present study was to assess the quality of traditional creams as regards bacterial contamination.
Materials and Methods: This was a cross-sectional study including a total of 250 traditional cream and 50 pasteurized cream samples collected in the south of Tehran retail shops. The samples were diluted in a phosphate-buffered saline, transferred to a rappaport-vassiliadis salmonella (rvs) enrichment broth according to the CDC procedures and incubated at 37° C in Hektoen enteric agar and bismuth sulfite agar media for 24 hours. Antimicrobial susceptibility testing was done using the Clinical and Laboratory Standards Institute (CLSI) procedures. On the following day the suspected colonies were examined for phenotype and finally confirmed by the API 20 E test.
Results: Of the 250 unpasteurized cream samples 15 (6%) were contaminated with Salmonella. Of the 7 serotypes identified, the most frequent Salmonella serotype was the infantis serotype with 7 cases (33.3%). Furthermore, Coliform bacteria such as Escherichia coli, Enterobacter, Klebsiella and Citrobacter were also isolated. The highest antibiotic resistance was to nalidixic acid (93.3%), tetracycline (73.3%) and trimethoprim (66.7%). None of the pasteurized cream samples was contaminated with Salmonella.
Conclusion: The results confirm the need for more effective control and monitoring of the traditionally prepared cream marketed in the city by the Food Control Authority. In addition, educating the public about the consumption of pasteurized cream can play a good role in reducing foodborne illnesses.

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Background and Aim: Nowadays foodborne diseases are a serious concern globally. Due to unsound use of antibiotics various pathogens are involved in foodborne diseases, S. aureus being the most common cause of food poisoning. Methicillin-resistant Staphylococcus aureus (MRSA) strains are a serious threat for the public’s health worldwide. The objective of this study was to determine the extent of contamination of foods offered in the South of Tehran, Iran with MRSA strains in 2018-19.
Materials and Methods: In this descriptive study, 560 food samples were collected from different regions in the south of Tehran, Shahr-e-Rey and Islamshahr between June 2018 and May 2019 and sent to a laboratory to determine the presence of S. aureus according to the Iranian National Standard No.1194 methods. In addition, the antibiotic sensitivity of the S. aureus species was determined using the Disk Diffusion Test.
Results: Of the 560 samples, 49 (8.7%) were found to be contaminated with S.aureus. Pastry, traditional ice cream and raw protein foods were the most contaminated foodstuffs. Four 4 (8.2%) of the 49 S. aureus isolates were found to be resistant to methicillin.
Conclusion: Considering the importance of S. aureus in causing food poisoning and the possibility of transfer of species resistant to antibiotics, especially methicillin, through foods, it is vital to pay special attention to sound use of antibiotics.