Isolation Of Enterobacter Sakazakii Research Articles

Isolation of Enterobacter sakazakii from Powdered Foods Locally Consumed in Nigeria

Isolation of Enterobacter sakazakii from Powdered Foods Locally Consumed in Nigeria

Evaluation of a Revised U.S. Food and Drug Administration Method for the Detection and Isolation of Enterobacter sakazakii in Powdered Infant Formula: Precollaborative Study

A revised U.S. Food and Drug Administration (FDA) method for the detection and isolation of Enterobacter sakazakii in powdered infant formula was developed based on real-time PCR technology complemented by culture isolation on chromogenic agars. A validation study was conducted to compare the revised FDA method to the reference FDA method. Casein and soy powdered infant formula inoculated with morphologically typical and atypical strains of E. sakazakii were analyzed. Valid results were obtained from 360 test portions and controls and showed that the revised FDA method is significantly better (P < 0.05) than the reference FDA method for the detection of typical E. sakazakii strains and the two methods are equivalent for the detection of atypical E. sakazakii strains.

Isolation of Enterobacter sakazakii from ass’ milk in Sicily: Case report, safety and legal issues

Enterobacter sakazakii (Es) infections are likely to involve newborns and infants, causing meningitis and necrotizing enterocolitis and sepsis. Contamination of infant formulae milk during factory production or bottle preparation is implicated. Es has been isolated from environmental sources and from food other than infant formula and milk powder, but why it is associated only with the consumption of infant formulae, is unclear. According to Regulation (EC) No. 2073/2005 on the microbiological criteria for foodstuffs, Es is considered a microorganisms of greatest concern in infant formulae and follow-on formulae. Es is included between "safety criteria". The isolation of two strains of Es from 50 samples of ass' milk in Sicily is described. The antibiotic resistance profile of the isolates revealed a multiple resistance profile, including fluoroquinolones, commonly used to treat the infections. The authors underline the importance of survey because in Italy ass' milk is considered one of the solutions for infants suffering from hypersensitivity to milk protein of some animal species. There is scarce information about the ecology and the uncertainty concerning the source of infection in the children and adults; the authors are concerned that ass' milk could become a high-risk food.

Surveillance and genotyping ofEnterobacter sakazakiisuggest its potential transmission from milk powder into imitation recombined soft cheese

To examine the presence of Enterobacter sakazakii in milk and milk-related products produced/distributed under Egyptian conditions and to probe possible transmission routes of the pathogen during the preparation of dairy products. One hundred and thirty-seven samples of milk and milk-related products were randomly collected from Egyptian markets and examined for the presence of Ent. sakazakii. The pathogen could be detected only in skimmed milk powder (SMP) and its related product, imitation recombined soft (IRS) cheese. Enterobacter sakazakii isolates recovered from these products were phenotypically similar and sensitive to all antibiotics examined in this study. They also showed indistinguishable banding patterns when subjected to macro-restriction profiling using pulsed-field gel electrophoresis (mrp-PFGE). One Ent. sakazakii isolate was inoculated into SMP that was used in the preparation of IRS cheese using two cheese making procedures. The pathogen could survive for up to 1 month in the IRS cheese prepared by either procedure. The simultaneous presence of Ent. sakazakii in SMP and IRS cheese samples collected within the same local market besides the phenotypic and genotypic similarities of isolates recovered from these samples suggested the possibility of Ent. sakazakii being transmitted from SMP into IRS cheese. This hypothesis was supported by the observation that the pathogen could survive in the IRS cheese prepared from contaminated SMP. The study highlights SMP and IRS cheese as potential transmission vehicles of Ent. sakazakii. It also raises concern on the microbiological safety of IRS cheese prepared from SMP.

Isolation of Enterobacter sakazakii from ass’ milk in Sicily: Case report, safety and legal issues

Isolation of Enterobacter sakazakii from ass’ milk in Sicily: Case report, safety and legal issues

Genotypic characterization of Enterobacter sakazakii isolates by PFGE, BOX-PCR and sequencing of the fliC gene

Enterobacter sakazakii is an emerging food-borne pathogen that can cause rare but severe forms of neonatal meningitis, bacteraemia and necrotizing enterocolitis. A rapid typing method at the strain level is needed to determine the monoclonality or polyclonality of the isolates during outbreaks. The BOX-PCR fingerprinting technique, which targets the repetitive BOX sequences, and sequencing of the flagellin gene, fliC, were evaluated against a panel of 27 Ent. sakazakii strains from clinical and environmental sources. The typeability and discriminatory power of the techniques were compared with those of pulsed-field gel electrophoresis (PFGE), the reference genotyping method. BOX-PCR results yielded 92% agreement with PFGE results, whereas fliC gene sequencing was poorly discriminative. In our study, BOX-PCR and PFGE were similarly discriminatory to type Ent. sakazakii strains. The weak variability of the Ent. sakazakii fliC gene was related to the absence of the variable central domain present in most fliC genes of Enterobacteriaceae. The BOX-PCR typing provides an accurate discrimination and a rapid answer to identify clonal isolates of Ent. sakazakii.

Isolation of Enterobacter sakazakii and other Enterobacter sp. from food and food production environments

Enterobacter sakazakii and other Enterobacter species have caused foodborne illnesses through consumption of a variety of foods, including infant foods. The prevalence of E. sakazakii and other Enterobacter sp. in infant food and milk formula, milk powder, cereal products, spices, sugar and food production environments were studied. A total of 106 samples were tested for the presence of E. sakazakii and other Enterobacter sp. The presence of E. sakazakii and Enterobacter sp. was detected using the FDA enrichment procedure and a chromogenic medium. E. sakazakii was isolated from 2/15 infant food formula, 2/8 infant milk formula, 1/18 cereal products. However none of the powder milk, spices, sugar and environmental samples were positive for E. sakazakii. E. agglomerans was isolated from infant food formula, infant milk formula, milk powder, cereal products, spices and environmental samples. E. cloacae was isolated from infant milk formula.

Characterization of a collection of Enterobacter sakazakii isolates from environmental and food sources

Enterobacter sakazakii has emerged as a rare cause of neonatal meningitis, septicemia and enterocolitis. Contaminated infant milk formula (IMF) has been identified as one infection route. A small number of clinical outbreaks have been epidemiologically linked to IMF contaminated post-pasteurization during manufacture and/or mishandled when reconstituted. Currently no agreed standardized typing protocol has been developed to trace E. sakazakii. The objectives of this study were to apply biochemical and genetic methods to characterize 51 environmental and food E. sakazakii isolates and 6 E. sakazakii type strains. Isolates were presumptively identified using biochemical profiles based on API 20E and ID32E methods and by culture on differential selective Druggan Forsythe Iversen (DFI) agar. Identification was subsequently confirmed by real time polymerase chain reaction (PCR). All but one of the isolates was identified as E. sakazakii by biochemical profiling. One isolate was identified as Escherichia vulneris by ID 32E and as Pantoea agglomerans by API 20E. All isolates produced green/blue colonies on DFI medium characteristic of this organism. Real time PCR could differentiate between E. sakazakii, Enterobacter spp. and other Enterobacteriacae. Analysis of RAPD banding patterns revealed 3 major clusters of E. sakazakii. There was a large degree of diversity noted amongst the remaining isolates. Our findings indicate that RAPD may be applied as a useful and reliable tool for direct comparison of E. sakazakii isolates providing traceability through the infant formula food chain.

Detection of Enterobacter sakazakii Strains by Real-Time PCR

A precise 5′ nuclease (TaqMan) real-time PCR was developed and validated in house for the specific detection of Enterobacter sakazakii isolates. Specifically designed nonpatented primers and a hydrolysis (TaqMan) probe were used to target the 16S rRNA gene. All 27 E. sakazakii and 141 non–E. sakazakii strains tested with the real-time PCR were identified correctly. To monitor false-negative results, an internal amplification control was coamplified with the same primers used for the E. sakazakii DNA. The detection probability of the assay was 56% when an E. sakazakii cell suspension containing 102 CFU/ml was used as template in the PCR (0.5 CFU per reaction) and 100% with a 103 CFU/ml suspension. This PCR assay should be very useful for the diagnostic detection of E. sakazakii in foods, especially powdered infant formula, after cultural enrichment.

Isolation of Enterobacter sakazakii and other Enterobacteriaceae from powdered infant formula milk and related products

The presence of Enterobacter sakazakii and other Enterobacteriaceae was surveyed in 82 powdered infant formula milk (IFM) and 404 other food products. The presence of Ent. sakazakii was detected using the conventional method (growth on violet red bile glucose agar plus yellow pigment production on TSA) and a new chromogenic medium (Druggan–Forsythe–Iversen agar, DFI) which enables results to be obtained 2 days earlier than the conventional method. Ent. sakazakii was isolated from 2/82 powdered IFM, 5/49 dried infant foods, 3/72 milk powder, 2/62 cheese products and various dry food ingredients, especially herbs and spices (40/122). Ent. sakazakii was isolated from 67 samples using the DFI medium, however only 19 of the samples were positive following the conventional method. The largest difference in isolation between the two methods was with dry food ingredients. Although Enterobacteriaceae were enumerated from one powdered IFM sample ( Klebsiella ozaenae, 200 cfu/g), 7/82 had detectable Enterobacteriaceae after enrichment in EE broth. Using the ISO 6579 2002 method and immuno-magnetic separation technique no Salmonella serovars were isolated from powdered IFM, dried infant foods or milk samples. Therefore hygienic production of powdered IFM and milk production as monitored by control of Salmonella and enumeration of Enterobacteriaceae did not control Ent. sakazakii.