{"title":"Contamination and antibiotic resistance profile of <i>Cronobacter sakazakii</i> isolated from raw milk and infant formula.","authors":"Zahra Taji, Mojtaba Bonyadian, Hamdallah Moshtaghi","doi":"10.18502/ijm.v18i2.21305","DOIUrl":null,"url":null,"abstract":"<p><strong>Background and objectives: </strong><i>Cronobacter sakazakii</i> is an opportunistic pathogen associated with severe fatal infections. This study aimed to investigate the contamination of raw milk delivered to a powdered milk factory and the produced powdered milk, with <i>C. sakazakii</i>, and also the antibiotic resistance patterns of the isolates.</p><p><strong>Materials and methods: </strong>During 2024, 120 raw milk and 60 powdered milk samples were collected from one of the milk powder processing plants in Shahrekord city. A peptone water medium supplemented with nutrients, followed by Cronobacter Selective Broth, was used as the enrichment medium. Chromogenic Cronobacter Isolation (CCI) agar was used to isolate the suspicious colonies. Biochemical tests were performed on the isolates. The PCR test was performed to confirm the molecular identity of the isolates. The antibiogram test was performed using the disk diffusion method on Mueller-Hinton agar.</p><p><strong>Results: </strong>A total of 14 suspected <i>C. sakazakii</i> colonies were isolated from the raw milk. However, the PCR test confirmed that only 2 isolates (1.67%) were <i>C. sakazakii</i>. Also, the results revealed that none of the powdered milk samples were contaminated with <i>C. sakazakii.</i> The antibiogram test showed that the isolated <i>C. sakazakii</i> were resistant to erythromycin, ampicillin, amoxicillin, cephalexin, and tetracycline antibiotics.</p><p><strong>Conclusion: </strong>According to the results, some raw milk is contaminated with <i>C. sakazakii</i>, which is resistant to certain common antibiotics. However, contamination with this bacterium was not observed in the powdered milk samples. Given the importance of <i>C. sakazakii</i> in infant health, further studies should be conducted on other powdered milk and infant food supplements produced in Iran to ensure their safety.</p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 2","pages":"279-284"},"PeriodicalIF":1.9000,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13196792/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Iranian Journal of Microbiology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.18502/ijm.v18i2.21305","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MICROBIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Background and objectives: Cronobacter sakazakii is an opportunistic pathogen associated with severe fatal infections. This study aimed to investigate the contamination of raw milk delivered to a powdered milk factory and the produced powdered milk, with C. sakazakii, and also the antibiotic resistance patterns of the isolates.
Materials and methods: During 2024, 120 raw milk and 60 powdered milk samples were collected from one of the milk powder processing plants in Shahrekord city. A peptone water medium supplemented with nutrients, followed by Cronobacter Selective Broth, was used as the enrichment medium. Chromogenic Cronobacter Isolation (CCI) agar was used to isolate the suspicious colonies. Biochemical tests were performed on the isolates. The PCR test was performed to confirm the molecular identity of the isolates. The antibiogram test was performed using the disk diffusion method on Mueller-Hinton agar.
Results: A total of 14 suspected C. sakazakii colonies were isolated from the raw milk. However, the PCR test confirmed that only 2 isolates (1.67%) were C. sakazakii. Also, the results revealed that none of the powdered milk samples were contaminated with C. sakazakii. The antibiogram test showed that the isolated C. sakazakii were resistant to erythromycin, ampicillin, amoxicillin, cephalexin, and tetracycline antibiotics.
Conclusion: According to the results, some raw milk is contaminated with C. sakazakii, which is resistant to certain common antibiotics. However, contamination with this bacterium was not observed in the powdered milk samples. Given the importance of C. sakazakii in infant health, further studies should be conducted on other powdered milk and infant food supplements produced in Iran to ensure their safety.
期刊介绍：
The Iranian Journal of Microbiology (IJM) is an international, multi-disciplinary, peer-reviewed journal that provides rapid publication of the most advanced scientific research in the areas of basic and applied research on bacteria and other micro-organisms, including bacteria, viruses, yeasts, fungi, microalgae, and protozoa concerning the development of tools for diagnosis and disease control, epidemiology, antimicrobial agents, clinical microbiology, immunology, Genetics, Genomics and Molecular Biology. Contributions may be in the form of original research papers, review articles, short communications, case reports, technical reports, and letters to the Editor. Research findings must be novel and the original data must be available for review by the Editors, if necessary. Studies that are preliminary, of weak originality or merely descriptive as well as negative results are not appropriate for the journal. Papers considered for publication must be unpublished work (except in an abstract form) that is not under consideration for publication anywhere else, and all co-authors should have agreed to the submission. Manuscripts should be written in English.
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