Resistance of staphylococci to methicillin is important especially in the case of Staphylococcus aureus isolates. Its impact in veterinary medicine is not exactly specified in coagulase-negative staphylococci; however, these staphylococci may represent an important reservoir of resistance genes. The study aimed at detecting resistance to methicillin in coagulase-negative staphylococci from raw materials and foodstuffs of animal origin and assessing the tests frequently used to determine this resistance. Coagulase-negative staphylococci (198 isolates of 12 species) were tested. Resistance to methicillin was determined by the disk diffusion method using oxacillin and cefoxitin disks, microdilution method, detection of PBP2a and the mecA gene. Of the tested isolates, 109 (55.1%) were classified as resistant by the diffusion test with oxacillin, 32 isolates (16.2%) by the test with cefoxitin and 50 isolates (25.3%) on the basis of oxacillin minimum inhibitory concentration (MIC). No resistant isolates were incorrectly identified as susceptible when using the disk diffusion method with oxacillin (sensitivity of 100%). However, apart from 22 correctly classified resistant isolates, another 87 isolates were incorrectly identified as resistant as well (specificity of 50.6%). The test with cefoxitin showed the lowest (45.5%) sensitivity in determination of resistant isolates. By contrast, this test was the most precise in classification of resistant isolates (specificity of 87.5%). When using the microdilution method, resistant strains were identified with the sensitivity and specificity of 68.2% and 80.1%, respectively. The results revealed substantial variability of methicillin-resistant isolates ranging from 16.2% to 55.1%, depending on the phenotyping methods and recommended interpretation criteria used. Therefore, it is advisable to reconsider the current interpretation criteria in the case of coagulasenegative staphylococci of animal origin (with the exception of S. epidermidis).
- Klíčová slova
- gen mecA, koaguláza negativní stafylokoky,
- MeSH
- bakteriální léková rezistence * genetika MeSH
- cefoxitin MeSH
- mikrobiální testy citlivosti klasifikace metody MeSH
- mléčné výrobky mikrobiologie MeSH
- mléko mikrobiologie MeSH
- oxacilin MeSH
- proteiny vázající penicilin izolace a purifikace MeSH
- rezistence na methicilin * MeSH
- senzitivita a specificita MeSH
- Staphylococcus * genetika klasifikace účinky léků MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
Geographically related Staphylococcus epidermidis isolates from human patients (n=30), dairy farms (farmers and individual raw milk from cattle, n=36) and a dairy plant (n=55) were examined for epidemiological relatedness by pulsed-field gel electrophoresis and, using in vitro methods, for the ability to produce biofilm and antimicrobial resistance. Methicillin-resistant isolates (MRSE) were also identified and characterized. Isolates from farmers and dairy cattle were found to be genetically related, while isolates from human patients were highly diverse. Some dairy plant isolates (18.2%) were closely related to those from dairy farms. Biofilm production and resistance to antimicrobial agents were most typical for isolates from human patients, of which 76.7% were MRSE. Methicillin resistance was also widespread in farm-related isolates (61.1%). This study indicates the possible transmission of S. epidermidis between cattle and farmers. Dairy products were not proven to be an important source of either human infections or methicillin-resistant strains.
- MeSH
- biofilmy růst a vývoj MeSH
- DNA bakterií genetika MeSH
- DNA fingerprinting MeSH
- fenotyp MeSH
- genotyp MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- mikrobiologie životního prostředí MeSH
- mléko mikrobiologie MeSH
- molekulární epidemiologie MeSH
- pulzní gelová elektroforéza MeSH
- shluková analýza MeSH
- skot MeSH
- Staphylococcus epidermidis klasifikace genetika izolace a purifikace fyziologie MeSH
- techniky typizace bakterií MeSH
- zemědělství MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Isolates from the "farm to fork" samples (182 isolates from 2779 samples) were examined genotypically (icaAB genes) and phenotypically (in vitro biofilm formation, typical growth on Congo red agar; CRA) with the aim to assess the risk of penetration of virulent strains of Staphylococcus epidermidis into the food chain. The contamination of meat and milk products was significantly higher in comparison with raw materials. Contamination of contact surfaces in the meat-processing plants was significantly lower than that of contact surfaces in the dairy plants. The ica genes (which precondition the biofilm formation) were concurrently detected in 20 isolates that also showed a typical growth on CRA. Two ica operon-negative isolates produced biofilm in vitro but perhaps by an ica-independent mechanism. The surfaces in the dairy plants and the milk products were more frequently contaminated with ica operon-positive strains (2.3 and 1.2 % samples) than the other sample types (0-0.6 % samples).
- MeSH
- biofilmy MeSH
- kontaminace potravin MeSH
- kontaminace zdravotnického vybavení MeSH
- manipulace s potravinami přístrojové vybavení MeSH
- masné výrobky mikrobiologie MeSH
- maso mikrobiologie MeSH
- mléčné výrobky mikrobiologie MeSH
- mléko mikrobiologie MeSH
- operon MeSH
- potravinářská mikrobiologie MeSH
- pulzní gelová elektroforéza MeSH
- skot MeSH
- Staphylococcus epidermidis fyziologie genetika izolace a purifikace MeSH
- virulence MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
The aim of this study was to determine both the occurrence and the genetic basis of resistance to erythromycin among 1 235 Staphylococcus spp. isolates obtained between 2000 and 2006 from (a) raw milk and meat (1 704 samples), (b) foodstuffs produced from these (451 samples), and (c) contact surfaces at processing plants and dairy farms (363 samples) in the Czech Republic. Isolates were screened by broth microdilution method for resistance to erythromycin and further 11 antimicrobial agents. In addition, isolates were screened by agar dilution (erythromycin range 1–128 mg/l) and D-zone test for inducible resistance to macrolides, lincosamides and streptogramin B (iMLSB). Forty isolates were found to be either resistant, or intermediate, to erythromycin (3.2% of isolates); of these, more than 50% were identified as S. epidermidis. A total of 15 (1.2%) resistant isolates of staphylococci originated from foodstuffs. Resistance mediated by methylation – i.e. iMLSB-resistance (10 isolates with the erm(A) or erm(C) gene) and constitutive MLSB-resistance (one isolate with the erm(B) and erm(C) genes) – exhibited a significantly high level of resistance to erythromycin with minimum inhibitory concentrations (MIC) of 64 – >128 mg/l (MICmode = >128 mg/l). In contrast, the efflux mechanism encoded by the msr(A) gene (13 isolates; MICrange = 4–128, MICmode = 128 mg/l), the inactivation mechanisms of resistance encoded by the mph(C) gene (three isolates; MICrange = 8–32 mg/l), and/or their combination (13 isolates; MICrange = 4–128, MICmode = 64 mg/l) led to lower MIC values. The efflux gene msr(A) dominated among the erythromycin-resistant isolates (65% of resistant isolates). This first report on the resistance of Staphylococcus spp. to erythromycin in the Czech Republic illustrates that, while occurrence was low, isolates from food were nevertheless carriers of erm(A), erm(B), erm(C), msr(A) and mph(C) genes for resistance to erythromycin and, therefore, represent a potential thread to humans.
Biofilmy jsou společenství mikroorganismů s architekturou, na které se podílejí mikroorganismy a jimi produkované biotické látky spolu se zachycenými organickými a anorganickými látkami z vnějšího prostředí. Vážným problémem jsou v humánním lékařství. Mikrobiální biofilmová společenství jsou problémem i v potravinářském průmyslu, kde patogenní mikroorganismy uvolněné z biofilmové struktury mohou způsobovat kontaminace potravin a surovin pro jejich výrobu. Společenství jako celek, ale i jednotlivé buňky, vykazují zvýšenou rezistenci k sanitačním a dezinfekčním prostředkům, která způsobuje, že tyto komunity je nesnadné odstraňovat nebo mikroorganismy v nich inaktivovat. Zejména modelové studie, molekulárně-genetické a mikroskopické metody, mohou přispět k dalším poznáním, která povedou k prevenci a k inaktivaci mikrobiálních společenství na kontaktních površích technologických zařízení potravinářských podniků. Dá se očekávat, že tyto studie přinesou poznatky potřebné jak z pohledu lidského zdraví, tak pro zpracovatelské a výrobní potravinářské závody.
Biofilms are microbial communities whose architecture includes microorganisms, biotic substances produced by these microorganisms and attached organic and inorganic substances from the environment. They pose a serious problem in human medicine. Microbial biofilm communities are also cause for concern in the food industry since pathogenic microorganisms released from the biofilm may contaminate food and raw materials for food production. Not only the microbial community as a whole but also particular cells exhibit increased resistance to sanitation measures and disinfectants which makes it difficult to remove the biofilm or to inactivate particular built up microorganisms. Mainly model studies and molecular genetic and microscopy methods can contribute to better understanding of this issue, and thus to prevention and inactivation of microbial communities on food contact surfaces of equipment in the food production plants. Such studies would be of benefit to both health care and food processing and production.
- MeSH
- antibakteriální látky aplikace a dávkování škodlivé účinky MeSH
- Evropská unie MeSH
- finanční podpora výzkumu jako téma MeSH
- infekce vyvolané Escherichia coli epidemiologie MeSH
- maso mikrobiologie statistika a číselné údaje MeSH
- mikrobiální testy citlivosti metody statistika a číselné údaje MeSH
- mléko mikrobiologie statistika a číselné údaje MeSH
- mnohočetná bakteriální léková rezistence genetika účinky léků MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Geografické názvy
- Česká republika MeSH
