Emil Tirziu

Environmental Occurrence and Antibiotic Susceptibility Profile of Listeria monocytogenes at a Slaughterhouse Raw Processing Plant in Romania

This survey was conducted to investigate the occurrence and antimicrobial susceptibility of Listeria monocytogenes isolates in the environment of a pig slaughterhouse raw processing plant complex in western Romania. A total of 97 environmental samples from food contact (n = 60) and nonfood contact (n = 37) surfaces were examined with standard methods. The susceptibility of the isolates to 17 antimicrobial agents was determined with the VITEK 2 automated system. Overall, 25 (25.8%) samples were positive for L. monocytogenes , with recovery rates of 23.3% (n = 14) and 29.7% (n = 11) for food contact and nonfood contact surfaces, respectively. All 25 tested isolates were resistant to benzylpenicillin, imipenem, and fusidic acid. Resistance was observed to oxacillin (23 isolates; 92%), fosfomycin (23 isolates; 92%), clindamycin (22 isolates; 88%), rifampin (14 isolates; 56%), trimethoprim-sulfamethoxazole (12 isolates; 48%), tetracycline (11 isolates; 44%), and ciprofloxacin (1 isolate; 4%). No resistance was found to seven tested agents: gentamicin, moxifloxacin, erythromycin, linezolid, teicoplanin, vancomycin, and tigecycline. All tested L. monocytogenes isolates were resistant to four to nine antimicrobial agents. These results indicate a high prevalence of multidrug-resistant L. monocytogenes isolates in this pork-processing environment, providing baseline information for hygienists and public health specialists.

Salmonella in raw chicken meat from the Romanian seaside: frequency of isolation and antibiotic resistance.

The purpose of this study was to investigate the occurrence of Salmonella in raw chicken meat samples collected at the Romanian seaside and to evaluate the antimicrobial susceptibility of the isolates. In 2012, 317 chicken meat samples from slaughterhouses (n = 289) and retail markets (n = 28) were evaluated. Overall, 13.2% (42) of the samples contained Salmonella; 12.8% (37) and 17.8% (5) from the chicken carcasses at slaughterhouses and the fresh meat from retail markets, respectively. Eight serotypes of Salmonella enterica subsp. enterica were identified: Infantis (18 isolates), Bredeney (7), Virchow (6), Djugu (4), Grampian (4), Brandenburg (1), Derby (1), and Ruzizi (1). The isolates were resistant to tetracycline (66.6% of isolates), nalidixic acid (64.3%), sulfamethoxazole (64.3%), ciprofloxacin (61.9%), streptomycin (59.5%), trimethoprim (33.3%), ampicillin (9.5%), chloramphenicol (7.1%), and gentamicin (2.4%). No resistance was found to cefotaxime and ceftazidime. Thirty (71.4%) of the 42 tested isolates had multidrug resistance patterns to at least two antimicrobials. This survey highlighted a multidrug-resistant Salmonella contamination rate in raw chicken meat in this area of Romania, which can seriously threaten human health.

Antimicrobial effect of probiotics on bacterial species from dental plaque.

INTRODUCTION The antimicrobial role of probiotic Lactobacillus casei subspecies casei DG (L. casei DG) and of the mix culture of probiotic Lactobacillus acidophilus LA-5 and Bifidobacterium BB-12 was tested on species of Staphylococcus, Streptococcus, Pasteurella, and Neisseria genera from supragingival sites from dogs with dental disease of different breed, age, sex, weight, and diet. The research was conducted on these four genera because of their importance in zoonotic infections after dog bites. METHODOLOGY Species from Staphylococcus, Streptococcus, Pasteurella, and Neisseria genera were isolated and identified. To test the antimicrobial efficacy of L. casei DG and the mixed culture of probiotic L. acidophilus LA-5 and Bifidobacterium bifidum BB-12 on the pathogenic species, the agar overlay method was used. RESULTS L. casei DG had a bactericidal effect on all analyzed species isolated from Staphylococcus, Streptococcus, Pasteurella, and Neisseria genera after 24 hours of incubation. The mixed probiotic culture made up of L. acidophilus LA-5 and Bifidobacterium BB-12 species had no bactericidal effect on the species of Staphylococcus and Streptococcus genera, which were resistant. However, it had a bacteriostatic effect on several species of Pasteurella and Neisseria genera. CONCLUSIONS This work highlights the antimicrobial potential of probiotics in vitro, demonstrating that the probiotic L. casei DG has a bactericidal effect on all analyzed species isolated from dental plaque and that the mix culture of probiotic L. acidophilus LA-5 and Bifidobacterium BB-12 has only a bacteriostatic effect.

Microbial biofilm in human health - an updated theoretical and practical insight

Abstract The term biofilm designates an aggregate of microorganisms belonging to one or more species which adhere to various surfaces but also to each another. These microbial communities are included and interconnected within an organic structure known as slime, composed of protein substances, polysaccharides, and DNA. The Center for Disease prevention and control considers infections with bacteria in biofilms among the 7 most important challenges which must be overcome in order to improve the safety of health services. The risk of microbial biofilm development exists for a long list of medical devices and equipment, as well as in certain diseases such as cystic fibrosis. An aggravating aspect is represented by the almost 1,000 times higher antimicrobial resistance of bacteria growing and multiplying within biofilms. Thus, in case of biofilm-infected medical devices, the resistance to antimicrobial treatments requires the removal of the device which essentially means the failure of the exploratory or therapeutic intervention in question. The role of microbial biofilms in medical pathology is a subject that raises interest for both researchers and clinicians in order to establish new methods for prevention and treatment of biofilms. This paper is intended as an overview in the management of microbial biofilms, presenting future insights, with technological progress in microscopy, molecular genetics, and genome analysis. Therefore the present paper will focus on describing the mechanisms involved in biofilm development, biofilm related infections, methods of detection and quantification of microbial communities and therapeutical approaches.