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Vibrio parahaemolyticusis a marine bacterium recognized as an important cause of gastroenteritis in humans consuming contaminated shellfish. In recent years, increasing resistance to ampicillin and aminoglycosides has been observed among V. parahaemolyticusisolates. However, the first-line antimicrobials such as tetracyclines and fluoroquinolones remained highly effective against these bacteria. The aim of this study was to evaluate the occurrence of V. parahaemolyticusin live bivalve molluscs available on the Polish market and to determine the antimicrobial resistance of the recovered isolates. A total of 400 shellfish samples (mussels, oysters, clams, and scallops) from 2009 to 2012 were tested using the International Organization for Standardization standard 21872-1 method and PCR for the species-specific toxRgene. Antimicrobial susceptibility of the isolates was determined using a microbroth dilution method. V. parahaemolyticuswas identified in 70 (17.5%) of the 400 samples, and the toxRgene was confirmed in 64 (91.4%) of these isolates. Most of the isolates were recovered from clams (31 isolates; 48.4% prevalence) followed by mussels (17 isolates; 26.6% prevalence). More V. parahaemolyticus–positive samples were found between May and September (22.7% prevalence) than between October and April (11.4% prevalence). Antibiotic profiling revealed that most isolates were resistant to ampicillin (56 isolates; 87.5%) and to streptomycin (45 isolates; 70.3%), but all of them were susceptible to tetracycline and chloramphenicol. Forty-one isolates (64.1%) were resistant to two or more antimicrobials; however, only one isolate (1.6%) was resistant to three antimicrobial classes. The antimicrobials used in treatment of human V. parahaemolyticusinfection had high efficacy against the bacterial isolates tested. This study is the first concerning antibiotic resistance of V. parahaemolyticusisolates in Poland, and the results obtained indicate that these bacteria may pose a health risk to consumers.

The purpose of the present study was to determine the prevalence of Campylobacterin poultry carcasses at slaughter in Poland. For the isolated strains, resistance to selected antibiotics and the associated genetic determinants were identified. A total of 498 Campylobacterisolates were obtained from 802 poultry samples during the 2-year study period. Strains were identified to species with the PCR method; 53.6% of the strains were Campylobacter jejuniand 46.4% were Campylobacter coli. A high percentage of the tested Campylobacterstrains were resistant to ciprofloxacin and nalidixic acid (74.1 and 73.5%, respectively) followed by tetracycline (47.4%) and streptomycin (20.5%). Only one C. jejuniand two C. coliisolates were resistant to gentamicin. Seventy-nine (15.9%) of the 498 strains were resistant to three or more classes of antibiotics examined. Higher levels of resistance, irrespective of the antimicrobial agent tested, were found within the C. coligroup. Almost all strains resistant to quinolones (99.5%) and to tetracycline (99.6%) carried the Thr-86-to-Ile mutation in the gyrAgene and possessed the tet(O)marker, respectively. All isolates resistant to erythromycin had the A2075G mutation in the 23S rRNA gene. These results reveal that poultry carcasses in Poland are a reservoir of potentially pathogenic and antimicrobial-resistant Campylobacterstrains for humans, which may pose a public health risk.

AbstractFour hundred seventeen retail beef meat samples purchased in the eastern part of Poland during October 2009 to January 2011 were tested for the presence of Listeria monocytogenes. It was found that 81 (19.4%) of them were positive for this microorganism as identified by the culture and polymerase chain reaction (PCR) methods. Molecular serotyping performed by PCR revealed that the majority of the isolates (50 strains; 61.7%) were of 1/2a serotype. Furthermore, 26 (32.1%) L. monocytogenesstrains were classified as 1/2c serotype, and only five strains belonged to serotypes 1/2b or 4b (four and one isolates, respectively). All the isolates were positive for the inlA, inlC, inlJ,and lmo2672sequences, whereas two L. monocytogenes(both of 4b serotype) had another virulence marker gene—llsX. The results of the antimicrobial resistance revealed that the strains were sensitive to most of the antimicrobials used in the study except oxacillin (62.7% resistant strains). Several isolates (17.3%) were also resistant to ceftriaxone. Our results indicate that L. monocytogenesidentified in raw beef meat possessed virulence markers that make them potentially pathogenic for humans. Therefore, this kind of food may create a public health concern.

Campylobacteris one of the most common causes of foodborne bacterial infections worldwide. Why poultry has been shown to be one of the most significant sources of these bacteria, ruminants, especially cattle, are also responsible for a high number of human Campylobacter jejuni, and to a lesser extent Campylobacter coli, infections. In this study, bovine and pig carcasses in Poland were investigated for the presence of Campylobacterand for their antimicrobial resistance. A total of 204 swabs from bovine carcasses and 355 swab samples from pig carcasses were tested during 2014–2018. Campylobacterwas identified in 129 (36.3%) of the pig and in 11 (5.4%) of the bovine carcasses, respectively. The pig isolates were classified as C. coli(121; 34.1%) or C. jejuni(8; 2.3%), whereas the bovine Campylobacterwere identified either as C. jejuni(8; 3.9% isolates) or C. coli(3; 1.5% strains). Resistance of the isolates (n= 140) to erythromycin, ciprofloxacin, nalidixic acid, streptomycin, and tetracycline revealed that the vast majority of C. coliwas resistant to streptomycin (106 isolates; 85.5%), tetracycline (97; 78.2%), nalidixic acid (90; 72.6%), and ciprofloxacin (88; 71.0%). Among C. jejuniisolates (n= 16) the resistance rates to all antibiotics were lower than in C. coli, irrespective of the origin. A total of 74 of 121 (61.2%) C. coliisolates from the pig carcasses and one of three such isolates from the bovine samples were multiresistant. Most of the C. coli(64 isolates; 85.3%) had the ciprofloxacin+nalidixic acid+streptomycin+tetracycline resistance profile. The results suggest that pig and bovine carcasses may be an underestimated reservoir of Campylobacter, especially for C. coliin pigs. The high antimicrobial resistance rates of such strains to streptomycin, quinolones, and tetracyclines highlight the need for monitoring of these bacteria in such food and food products.

Removal of carbonaceous matters over alumina supported chromium and platinum chromium catalystsPlatinum, both alone and with a low and high amount of chromium as an additive supported on alumina, was studied as a catalyst. These catalysts were examined in the removal of the carbonizate as a model material. It was found that the 2Cr/Al2O3catalyst showed a significant increase in the catalytic activity as compared to 20Cr/Al2O3. An addition of platinum was found to cause a decrease of activity.