Microbiol. Res., Volume 7, Issue 1 (July 2016) – 7 articles

The transfer of antibiotic resistance via the food chain is a global concern. Nevertheless, more attention is required to non-pathogenic strains, such as spoilage bacteria, which could transmit genes to pathogens. Although Lactic Acid Bacteria are microorganisms generally recognized as safe, Leuconostoc mesenteroides may reach and maintain high concentration levels on the surface of cooked products and ready-to-eat products throughout the entire shelf life. It is therefore important to consider the possibility for this species to carry antibiotic- resistance genes. The present research deals with the antibiotic susceptibility profile of strains of L. mesenteroides, isolated from vacuum packaged cooked meat products. In this study, the antimicrobial susceptibility of L.mesenteroides, previously isolated from cooked ham, was investigated through disk diffusion assay according to CLSI standards. Isolated strains from ready-to-eat food show high levels of resistance to ampicillin and methicillin and, according to a settled panel of 21 antibiotics, the antibiotic resistance was demonstrated for the 50% of the tested molecules. Full article

Bacteriocins are proteinaceous toxin produced by bacteria to inhibit the growth of similar or closely related bacteria. Among lactic acid bacteria (LAB), bacteriocins are produced by Streptococcus, Pediococcus, Lactobacillus, etc. In recent years, bacteriocin-producing LAB have attracted significant attention because of their generally recognized as safe status and potential use as safe additives for food preservation. Incorporation of bacteriocins into packaging films to control food spoilage and pathogenic organisms has been an area of active research for last decade. Antimicrobial packaging film prevents microbial growth on food surface by direct contact of the package with the surface of food. The objectives of this study were to isolate bacteriocin-producing LAB from Yakult^®, develop antimicrobial packaging system and evaluate their antimicrobial effects on selected spoilage and pathogenic microorganisms. For this reason, the antimicrobial packaging film was made by using the bacteriocin by Lactobacillus casei and coating it or adsorbing it onto the surface of different packaging materials. The antimicrobial activity of the coated films was tested by agar diffusion assay against the test organisms Escherichia coli and Staphylococcus aureus. The results obtained proved that bacteriocins can be used to inhibit both the test organisms. Thus antimicrobial packaging systems can be developed using bacteriocins thereby reducing the risk of pathogen development, as well as extending the shelf life of foods. Full article

Arcobacters are food and waterborne pathogens associated with human and animal infections. The objective of the present study was to investigate the prevalence and diversity of Arcobacter spp. in commercially sold chicken meat in İzmir region of Turkey. For this purpose, 100 samples including legs (n = 40), 17 chicken quarters (n = 17), drumstickers (n = 16), breasts (n = 11), wings (n = 10), and carcasses (n = 6) were collected from different retail markets. A total of 65 isolates were confirmed as Arcobacter spp. from 55 samples by genus-specific polymerase chain reaction (PCR). The prevalence of Arcobacter spp. was 32.5, 81.3, 64.7, 72.7, 83.3, and 50% for legs, drumstickers, chicken quarters, breasts, carcasses and wings, respectively. Based on the multiplex-PCR, most of the isolates were identified as A. butzleri (n = 45, 80%), followed by A. cryaerophilus (n = 2, 3.6%), A. skirrowii (n = 1, 1.8%) and 17 isolates (30.9%) could not be identified at the species level. Full article

The aim of the study was to investigate vancomycin and high-level aminoglycoside resistance (HLAR) in Enterococcus species by phenotypic and genotypic methods. A hundred Enterococcus strains were included in the study. Antimicrobial susceptibilities of strains were investigated by automated system, betalactamase production was investigated by nitrocefin disks, vancomycin resistance and HLAR were investigated by gradient diffusion method (GDM) and disk diffusion method, respectively. For detection of vancomycin and high-level gentamicin resistance (HLGR) genes, polymerase chain reaction was used. Teicoplanin linezolid, vancomycin, ampicillin, penicillin are the most susceptible antibiotics and strains were detected not to produce beta lactamase. Vancomycin resistance was detected in ten isolates by automated system and in only five isolates by GDM. Five isolates carrying VanA gene were determined. The ratio of HLGR and high-level streptomycin resistance was found 40 and 63% respectively. aac (6’)-1eaph (2’’)-1a gene was detected in 58% of strains. E. faecium strains were found more resistant to the antibiotics than the other species. Beta lactamase was detected in none of strains. The automated system detected vancomycin resistance in more strains than GDM. Therefore it is concluded that strains, which were detected to be resistant to vancomycin, should be confirmed by GDM. The ratio of VanA gene in strains is consistent with other studies. The HLAR ratio was found in about half of strains. The ratio of aac(6’)-1e-aph(2’’)-1a gene, which is the most reported gene in our country and other countries and one of the HLGR genes investigated in our study, was detected 58%. Full article

Due to the increasing prevalence of infections caused by resistant bacteria and especially multiple drug resistance Enterobacteriaceae, availability of alternative effective antibiotics is restricted. The goal of this study was to investigate the susceptibility profile of multiple drug resistance and extensively drug resistance Enterobacteriaceae isolated from various clinical samples to fosfomycin. A total of 303 non-duplicate Enterobacteriaceae isolates were collected. Identification and susceptibility testing were done according to standard microbiological procedures and the Kirby-Bauer test, respectively. Of all isolates, 272 (89.8%) and 26 (8.6%) were detected as multiple drug resistance and extensively drug resistance strains, respectively. The most effective antibiotic (98%) was fosfomycin, when compared with other antibiotics against multiple drug resistance and extensively drug resistance Enterobacteriaceae isolates. In this study, we find high levels of resistance to commonly used antibiotics. However, fosfomycin can be a good option for treating multiple drug resistance Enterobacteriaceae. Full article

Potato is the most important root crop in Bangladesh. The field production is very much lower compared to other developed countries. Pests and diseases hampered the production due to the prevailing climatic condition, which favors the development in Bangladesh of specific diseases. Among them Brown rot (Ralstonia solanacearum) is the most alarming disease at present and previous time. The major areas of Bangladesh have faced many hampers on this disease. The potato growers and businessmen of Bangladesh are facing much problems on this disease especially in case of export to other countries as Russia, Malaysia, Singapore, Indonesia, Sri Lanka, Thailand, Hong Kong, Vietnam, Maldives, Turkey, Azerbaijan, Ethiopia and Nigeria. But during last year Russian Government banned import potatoes from Bangladesh. So, from these perspectives, this concept paper was studied to evaluate the most appropriate status of this disease caused by organisms and its best control strategies to impart better production thinking for Bangladeshi potato growers, exporters and other related personnels. Full article

Mycobacterium avium subsp. paratuberculosis (MAP) is the etiologic agent of Johne’s disease, a chronic intestinal disease of cattle and other ruminants. Diagnostic culture for MAP is typically unrewarding until latter stages of the disease. This may be a consequence of oxidative damage to dormant organisms, which results from culture. The purpose of this investigation was to determine the effect of the commercial reducing agent Oxyrase^® for Broth (OB) on the recovery of dormant Mycobacterium smegmatis (MS) and MAP. Dormant organisms were inoculated into medium only or that supplemented with media containing serial dilutions of OB. Growth was monitored by optical density for up to 21 days. Treatment of MAP and MS with OB led to significant increases in recovery and growth yield. However, the concentration of OB necessary to promote recovery was dependent on the number of viable organisms present in seed cultures. Mitigating oxidative damage by using OB can facilitate the recovery of dormant mycobacteria. Whether this is a direct or indirect effect has yet to be be established. Full article