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Characterization of multiply resistant Proteus mirabilis isolates in Hungary
M Konkoly Thege1, S Nikolnikov
1National Institute of Hygiene, Budapest, Hungary.
Abstract:
According to a survey on tendencies of antibiotic resistance in Hungary (1974-1983), the emergence of multiresistant (MR) Proteus mirabilis isolates is a new phenomenon. A total of 60 strains resistant to 11-16 antibiotics were collected from various specimens and geographical locations. Except for cefoperazone, third generation cephalosporins, amikacin, netilmicin and ofloxacin were effective in vitro against multiply resistant P. mirabilis isolates. Out of them 62% belonged to O18, a serogroup not shown in early studies in Hungary; moreover, in serogroup-distribution the present collection differed sharply from isolates examined in 1956. All but two strains produced the same aminoglycoside-modifying enzyme ANT (2"), and all of them proved beta-lactamase positive in nitrocephin test. All multiresistant strains harboured 2-4 plasmids, whereas the sensitive isolates had no plasmids. The presence of two plasmids (62 and 22 Mdal) occurring in 85% of the isolates was a characteristic feature of the multiresistant P. mirabilis isolates. In contrast to these plasmids some other ones (17.5, 103 and 113 Mdal) could be transferred to Escherichia coli recipient. There was no relationship between plasmid profiles, serogroups and resistance patterns.
Insights
Multiresistant Proteus mirabilis strains emerged in Hungary, showing resistance to numerous antibiotics. These strains frequently carried specific plasmids, unlike sensitive isolates, indicating a new phenomenon in antibiotic resistance.
Area of Science:
- Microbiology
- Molecular Biology
- Epidemiology
Background:
- Antibiotic resistance is a growing global health concern.
- Proteus mirabilis is an opportunistic pathogen frequently associated with healthcare-associated infections.
- Previous studies in Hungary did not report multiresistant strains of P. mirabilis.
Purpose of the Study:
- To investigate the emergence and characteristics of multiresistant Proteus mirabilis isolates in Hungary.
- To identify the genetic basis of antibiotic resistance in these strains.
Main Methods:
- Collection and characterization of 60 multiresistant P. mirabilis clinical isolates from Hungary between 1974-1983.
- Antibiotic susceptibility testing against 11-16 antibiotics.
- Serogrouping of isolates.
- Detection of beta-lactamase and aminoglycoside-modifying enzymes (ANT(2")).
- Plasmid profiling and analysis, including transfer experiments to Escherichia coli.
Main Results:
- 60 multiresistant P. mirabilis strains were identified, exhibiting resistance to 11-16 antibiotics.
- Third-generation cephalosporins, amikacin, netilmicin, and ofloxacin showed in vitro efficacy.
- 62% of isolates belonged to serogroup O18, a novel finding for Hungarian P. mirabilis.
- All multiresistant strains harbored 2-4 plasmids; sensitive strains had none.
- A characteristic feature was the presence of two plasmids (62 and 22 Mdal) in 85% of multiresistant isolates.
Conclusions:
- The emergence of multiresistant Proteus mirabilis is a new phenomenon in Hungary.
- Specific plasmids, particularly the 62 and 22 Mdal types, are strongly associated with multiresistance in P. mirabilis.
- The genetic basis for resistance involves beta-lactamase and aminoglycoside-modifying enzymes.
- Further research is needed to understand the epidemiology and control of these resistant strains.