Microbiological Risks of Traditional Raw Cow's Milk Cheese (Korycinski Cheeses).

Traditional and regional foods have been increasing in popularity among consumers in Poland for many years. The observed trend of searching for natural and authentic taste encourages many producers to craft products from raw milk, including Korycinski cheeses. The aim of this study was to assess the microbiological hazards resulting from the presence of pathogenic bacteria in Korycinski cheeses available in retail trade. The tests were carried out using accredited methods, including the detection of the presence of Salmonella spp., the enumeration of Listeria monocytogenes, the enumeration of coagulase-positive staphylococci, and the detection of staphylococcal enterotoxins in food when the number of coagulase-positive staphylococci in the sample exceeded the limit of 105 cfu/g. The research material consisted of 45 Korycinski cheeses. The tests conducted revealed that Salmonella spp. was not detected in any of the examined cheeses. However, coagulase-positive staphylococci were present in 68.9% of the samples. In as many as 15 tested cheeses, the level of S. aureus contamination was above 105 cfu/g; therefore, these samples were tested for the presence of staphylococcal enterotoxins. The presence of staphylococcal enterotoxins was found in one Korycinski cheese. In four cheeses, the number of L. monocytogenes exceeded the level of 102 cfu/g, the limit specified in Regulation 2073/2005 on microbiological criteria for foodstuffs. The obtained research results confirm the validity of monitoring the microbiological quality of Korycinski cheeses and the need to increase awareness of ensuring proper hygienic conditions of production, including the increased risk associated with unpasteurized milk products.

Novel gyrase mutations and characterization of ciprofloxacin-resistant clinical strains of Enterococcus faecalis isolated in Poland.

The activity of ciprofloxacin, sparfloxacin and moxifloxacin was determined for 205 Enterococcus faecalis isolates from patients of five hospitals (Warsaw, Poland; collected from 2000 to 2002). Ciprofloxacin resistant and intermediate isolates were numerous (53.7%). Among them, highly resistant (MIC > or = 16 mg/l) isolates predominated (98%). Isolates resistant to ciprofloxacin were also resistant to sparfloxacin and moxifloxacin. The parC and gyrA QRDRs (quinolone-resistance-determining region) of 11 isolates with ciprofloxacin MICs from 1 to 256 mg/l were analysed by DNA sequencing. In ParC one kind of amino acid substitution (of Ser-85 to Ile) in 9 E. faecalis strains with MICs from 16 to 256 mg/l was observed. In GyrA Ser-84 was changed to one of four different amino acids: Arg, Ile, Cys or Tyr, however no association between the amino acid type and MIC value was found. The last two substitutions have not been reported to date for E. faecalis. Moreover, our results may suggest that mutations within parC and gyrA are associated with development of a high-level of ciprofloxacin resistance.

The distribution of enterotoxin and enterotoxin-like genes in Staphylococcus aureus strains isolated from nasal carriers and food samples.

Staphylococcus aureus strains were examined for the presence of 18 enterotoxin (se) and enterotoxin-like (sel) genes by PCR and four classic enterotoxins SEA to SED by reverse passive latex agglutination. We screened three groups of isolates: 53 recovered from food samples collected in years 2004-2005, 18--from food samples collected in the 1960s and 1970s and 30--from nasal carrier samples collected in the years 2000-2002. Eighty percent of all tested strains were se and sel positive, but the frequency of these genes was higher among nasal carrier strains (93%) than among food samples isolates (circa 76%). The enterotoxin genes cluster (egc) was the most prevalent among carrier strains (18/30-60%) and the least--among food strains isolated in the 1960s and 1970s (6/18 strains--33%). sea coding enterotoxin A, which was recognised as the major cause of staphylococcal food poisoning so far, was more often found among carrier strains than among the years 2004-2005 food strains (27% versus 11%), but it was the most frequent se/sel gene among food strains isolated in the 1960s and 1970s (10/18 strains). Moreover in our results certain se and sel genes coexisted, which was in accordance with current knowledge about movable genetic elements carrying those genes. The exception was for only one strain, which harboured the sole selr gene on a possibly new genetic element not yet described. As we found both types of egc, as well as seh (especially food samples strains) occurred alone in a majority of positive strains for each of those genes. The analysis of the results obtained by SET-RPLA method for the productivities of classical enterotoxins A-D and the results obtained by PCR for the presence of sea-sed genes revealed the correlation between each other. Only three of all sea-sed positive strains had silent genes--sed.

[Enterotoxin genes occurance among S. aureus strains isolated from inpatients and carriers]. / Wystkpowanie enterotoksyn u szczepów Staphylococcus aureus izolowanych od chorych hospitalizowanych i nosicieli.

We examined 44 inpatients and 66 carriers Staphylococcus aureus strains, isolated in years 2002-2005, for the presence of 18 enterotoxin genes (se/sel) (by PCR), the ability for A-D enterotoxin production (by SET-RPLA) and antibiotic resistance distribution (by disc diffusion method). se/sel genes were detected in 90,9% of all strains, sea (70,5%) and selk and selq (52,3%) - among inpatients strains and egc (65,2%) - among carriers strains were the most frequently se/sel genes found. Positive results of SET-RPLA were consistent with PCR results. There was no correlation observed between antibiotic resistance and se/sel genes distribution among tested S. aureus strains.

[Characteristic of clinical fluoroquinolone resistant isolates E. faecalis]. / Charakterystyka opornych na fluorochinolony szczepów Enterococcus faecalis izolowanych z materialu klinicznego.

In presented study we have characterized phenotype of clinical E. faecalis strains, fluoroquinolone susceptibility and the presence of two potential virulence factors--hemolysin/cytolysin and gelatinase. Eighty three of E. faecalis strains were isolated from clinical samples from patients of five Warsaw hospitals. Susceptibility to 18 antibiotics was assessed by the disk diffusion method (ace. NCCLS). The MIC of ciprofloxacin was determineted by agar dilution method and the MIC of sparfloxacin and moxifloxacin by the E-test (AB BIODISK). Hemolysin production was evaluated on Columbia agar medium supplemented with 5% horse blood. Gelatinase production was determinated by using two different methods: I - on the Todd-Hewitt agar containing gelatin (30 g/l) and II--on the trypticase soy agar supplemented with 1,5% skim milk. Fourty nine (59%) of the 83 isolates E. faecalis were ciprofloxacin resistant and 14 (16,9%) were ciprofloxacin intermediate. The majority of E. faecalis strains (57,8%) were higly resistant to ciprofloxacin (MIC > or = 32 microg/ml). All of ciprofloxacin resistant E. faecalis isolates were cross-resistant to the other fluoroquinolones, as well. Production of hemolysin was more frequent among ciprofloxacin resistant E. faecalis strains. The dependence between gelatinase production and fluoroquinolone:resistance was not observed. Both investigated methods of gelatinase activity detection gave the same results and can be used exchangeably. Hemolytic strains were more frequently isolated from urine (47,8%), however gelatinase producing strains were more frequently isolated from wounds (31,6%).

[The characteristic of Staphylococcus aureus strains isolated from food's samples]. / Charakterystyka szczepów Staphylococcus aureus izolowanych z próbek zywnosci.

The study was carried out of 22 isolates of S. aureus isolated from 7 different incriminated food's samples from foodborne-disease outbreaks. The possibility of these isolates to producing of enterotoxins by commercial test SET-RPLA (Oxoid) was tested. The genotyping of these isolates was done by pulse-filed gel electrophoresis, acc. to Pfaller in own modification. On the basis of the DNA restriction patterns of the 22 isolates--5 strains were singled out, one of these strains--strain V (isolat nr 7) was not relationship to others. It was found that this strain V was one enterotoxin produced. Additionaly, all tested strains, in spite of the strain nr V, were isolated from the 2 or 3 samples of different kinds of foods. In the present study it has been shown too, that several similar colonies should be isolated for farther studies to assess microbiological contamination of the food products properly.

[Microbiological external quality assurance program (MEQAP)--evaluation of results obtained in sanitary epidemiological laboratories in 2002]. / Program Zewnetrznej Oceny Jakosci Badan Mikrobiologicznych--ocena wyników sprawdzianu przeprowadzonego w 2002 roku w laboratoriach stacji sanitarno-epidemiologicznych.

The aim of this study was to evaluate reliability of identification and determination of sensitivity to antibiotics and chemotherapeutics of some Gram positive cocci strains in 34 sanitary-epidemiological stations. All laboratories engaged in this study received 3 strains: S. aureus (S. aureus SC+ CF+, resistant to methicillin., or S. aureus SC - CF+, sensitive to methicillin), coagulase-negative staphylococci (S. epidermidis or S. haemolyticus or S. saprophyticus) and Enterococcus sp. (E. faecalis HLAR-positive or E. faecalis HLAR-negative or E. faecium or E. gallinarum). All these strains previously were identified in Department of Bacteriology of National Institute of Hygiene. Of the 68 staphylococci strains tested, 66 isolates were correctly identified. Among the 34 enterococcal strains studied the greatest difficulty in identification was caused by E. gallinarum strain--(8 out of 13 strains were incorrectly recognised). The determination of the sensitivity of the control strains to antibiotics and chemotherapeutic agents, generally was performed correctly in accordance with to the NCCLS and national recommendations. Some incorrect results of the antibiograms were caused by an erroneous interpretation of the zones of inhibition.

[Drug sensitivity of Enterococcus sp. strains isolated from clinical material or from healthy persons]. / Lekowrazliwosc szczepów Enterococcus sp. izolowanych z materialu klinicznego oraz od osób zdrowych.

The aim of this study was to evaluate the drug susceptibility of Enterococcus sp. strains isolated in 2000-2001, from patients of five Warsaw's hospitals (154 strains) and from fecal samples of healthy persons (33 strains). On biochemical reaction profiles species of clinical enterococci were identified as: E. faecalis--66.2%, E. faecium--29.2%, E. hirae--1.9%, E. gallinarum--1.3%, E. casseliflavus--0.6% and E. avium--0.6%. The species of enterococci from stool's samples were identified as: E. faecalis--28 strains, E. durans--2 strains and single strains: E. faecium, E. gallinarum and E. casseliflavus. Susceptibility to 20 antibiotics was tested by disc diffusion method. None of these 187 enterococcal strains was vancomycin resistant; 3 strains of E. gallinarum and 1--E. casseliflavus demonstrated intermediately susceptibility to vancomycin, but they were susceptible to teicoplanin--phenotype Van C. Among clinical strains were resistant to penicillin--33.3% of E. faecalis and 100% of E. faecium, to ampicillin--over 80% of E. faecium and 1 strain of E. faecalis. None of these strains produced beta-lactamase. High-level resistance to aminoglicoside was expressed by 48 strains (47.1%) E. faecalis and 36 (80%) E. faecium isolated from clinical specimens. Both--HLR to streptomycin and gentamycin were found in 28.3% of E. faecalis and 68.9% of E. faecium. Among 33 strains isolated from fecal samples of healthy persons--3 of E. faecalis were resistant to streptomycin and one was resistant to both gentamicin and streptomycin. In general, enterococcal strains isolated from samples of healthy persons were susceptible to the most of used antibiotics. But to rifampicin none of these strains were susceptible. There were about 40% of E. faecalis strains isolated from healthy persons, resistant to tetracyline.