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  • Author or Editor: Hedda Milch x
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An account is given on the activity of the National Center for Phage Typing of Staphylococci in Hungary in the period between 1997 and 2000 related to methicillin resistant Staphylococcus aureus (MRSA) strains originating mainly from hospital infections and sporadic cases. The rate of multiresistant MRSA strains has decreased gradually from 98.1% in 1997 to 74.6% in 2000, accordingly the typability by phages showed a considerable improvement by the international basic phages. Resistance pattern of MRSA strains became narrower in the period of the examinations. With the exception of erythromycin the rate of resistance decreased probably as a consequence of the increased use of erythomycin. The typing method was completed with the phenotypic and genotypic characterization of macrolide resistance. Among 73 MRSA strains type A was the most frequent macrolide resistance group, while type B, C1 and C2 occurred rarely. Type A was frequent also among the few MSSA and CNS strains. Out of the 168 examined S. aureus strains ermA genes occurred in 81.5%; in MSSA and CNS strains ermC1 genes were frequent, both genes are responsible for the target modification. The msrA gene, encoding the increased efflux, occurred only in CNS strains. Comparing the results obtained by phenotyping (phage typing) and genotyping (AP-PCR) methods it is of note that MRSA strains which proved non-typable by phage typing gave suitable results by the AP-PCR.

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An account is given using typing methods and detection of virulence genes of different serotypes of Escherichia coli isolated in Hungary. By hybridization using SLT-I and SLT-II probes and PCR method using stx1-2, eae and ehx primers we could differentiate O157 strains of different serotypes into eight  (stx, eae, ehxA positive; stx, eae positive; stx, ehxA positive; stx positive; eae, ehxA positive; eae positive; ehxA positive; stx, eae, ehxA negative) types. The discriminatory power of phage typing proves to be much higher than that of the plasmid profile. RAPD typing with different primers could confirm or exclude the subtypes identity of the isolated E. coli O157 serotypes. Escherichia coli O157:HNM isolates could be sorted in six different phage types and six different RAPD types with ERIC-1, in five RAPD types with ERIC-2 and in seven types with M13 primers. Escherichia coli O157:H7 showed six different phage types and three RAPD types with ERIC-1 and ERIC-2 and five types with M13 primers. According to our results the standard PFGE protocol [32] gives the opportunity to differentiate epidemiologically independent but evolutionary related or unrelated isolates, but the practical value of PFGE method for epidemiological purposes must be confirmed by other or more restriction enzymes or using an other protocol. Summarizing our results we suggest the use of phage and RAPD typing and in doubtful cases the PFGE method.

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