Varying fitness cost associated with resistance to fluoroquinolones governs clonal dynamic of methicillin-resistant Staphylococcus aureus.

The purpose of this study was to investigate the impact of fluoroquinolone resistance on the existence and dynamic of MRSA clones. Resistance to ciprofloxacin was induced in strains of community-acquired (CA) MRSA from various sequence types and the fitness cost suffered by mutant derivatives measured in a propagation assay. In addition, the fitness of fluoroquinolone resistant health care-associated (HA) MRSA isolates from major clones prevalent in Hungary were compared with each other and with those of the CA-MRSA derivatives. The genetic background of fluoroquinolone resistance and fitness cost in CA-MRSA was investigated. The fitness cost observed in the CA-MRSA derivatives proved diverse; the derivatives of the ST30-MRSA-IV strain suffered significantly greater fitness cost than those of the ST8-MRSA-IV and ST80-MRSA-IV isolates. Strains from the New York-Japan (ST5-MRSA-II), South German (ST228-MRSA-I) and EMRSA-15 (ST22-MRSA-IV) HA-MRSA clones proved more viable than CA-MRSA derivatives with similar MIC values to ciprofloxacin and HA-MRSA strains from the Hungarian/Brazilian clone (ST239-MRSA-III). Our strains from the New York-Japan, South-German and EMRSA-15 clones seem to have a competitive edge over the tested CA-MRSA isolates in the health care setting. The greater fitness observed in our New York-Japan and South-German strains could account for the replacement by them of the Hungarian/Brazilian clone in Hungary about ten years ago. Alterations in relevant genes were detected. The Ser80 → Phe mutation in the grlA gene may have seriously compromised viability. Surprisingly silent nucleotide substitutions in the grlB gene seemed to impact fitness in derivatives of the ST30-MRSA-IV isolate.

Risk factors and prevalence of Demodex mites in young adults.

Demodex mites are ectoparasites often found in follicles of facial skin. Their role in human diseases is under investigation, and a growing number of studies indicated that they contribute to chronic inflammatory conditions of the skin, such as rosacea, blepharitis, otitis externa, alopecia and folliculitis. In our study we tested 96 healthy adults for the presence of Demodex mites. Risk factors influencing presence of mites and skin types of the tested individuals were evaluated. We found Demodex folliculorum or Demodex brevis in 17.7% of the samples, more frequently in males (21.9%) and in older adults (20%). Use of make-up seems to reduce the likelihood of Demodex carriage, while pet ownership, use of shared items and living in close contact with older adults had no significant influence of presence of mites. Demodex positive individuals described their skin to be drier, more prone to erythema, but less for folliculitis compared to Demodex negative subjects.

Monitoring of drug resistance in therapy-naïve HIV infected patients and detection of African HIV subtypes in Hungary.

Mutations in the HIV-1 pol gene associated with resistance to antiretroviral drugs in therapy-naïve Hungarian individuals transmitted as primary infection by their foreign sexual partners originated from African, Asian and other European countries had been analyzed. Drug resistance genotyping of HIV RT and PR genes were performed where mutations of 72 codons - among them 64 specific resistance codons representing 6 nucleoside reverse transcriptase inhibitor (NRTIs), 2 non-nucleoside reverse transcriptase inhibitor (NNRTIs) and 6 proteinase inhibitor (PRIs) drugs - had been analyzed by Truegene HIV-1 Genotyping kit and OpenGene Sequencing System. Viral variants harboring resistance mutations in the po l gene were detected in 14% of the subjects. The highest rate of resistance to a single class of inhibitors was detected towards PR inhibitors (12%), followed by NRTI (8%) and NNRTI (5%). On the contrary, 25% of viruses transmitted by homosexual activity contained mutations led to resistance to NNRT. Viruses from 11 percent of cases were resistant to 2 classes of inhibitors, and 7 percent to three classes of inhibitors. Based upon sequence data non-B subtypes and CRFs were detected in more than 71% of cases. HIV-1 C (10.7%), HIV-F1 (7.2%) and HIV-1 G (3.6%) were detected as the more frequent subtypes. Among the HIV-1 recombinant viruses CRF02_AG variants were found more frequently (28.5%) followed by CRF06_cpx (17.8%) indicating penetration of non-B subtypes and recombinant African variants into Hungary, which raises serious clinical and public health consequences.

Connatal listeriosis--a case report and the possibilities of microbiological diagnosis.

The third most frequent agent of perinatal bacterial meningitis is Listeria monocytogenes, in Hungary, its occurrence is, however, uncommon. This raises the possibility of diagnostical mistakes. A connatal listeriosis case validated microbiologically referred to in this report calls attention to Listeria, as a rare but relevant pathogen of neonatal infections. If clinical background suggests infection, the pathogenic role of L. monocytogenes should be taken into consideration. The etiological significance of the agent has to be verified by a competent clinical microbiology laboratory, since maternal listeriosis should be treated and the serious connatal manifestations should be prevented. Epidemiology of perinatal infection by L. monocytogenes, and its diagnostic tools especially the use of selective media are discussed.

Emergence of antiretroviral drug resistance in therapy-naive HIV infected patients in Hungary.

Mutations in the HIV-1 genes associated with resistance to antiretroviral drugs were detected also in primary HIV infected individuals who did not receive antiretroviral treatment. Drug resistance genotyping of HIV pol gene was done by in situ DNA hybridization using a Line Probe Assay and by direct sequencing. Viral variants harbouring resistance mutations such as: M41, T69R, K70R, M184V, T215Y in the pol gene were detected in 14% of the subjects. HIV mutants resistant to NRT inhibitors were found in 10 and 20% of patients infected before and after the year 2000, respectively. Multiple drug resistant viruses (2-3 drug classes) were present in 3.5% of the mainly recently infected patients. In protease gene only minor resistant mutations were found such as L101 and A71V. These findings indicate the evolution of drug resistance showing a correlation with the time of introduction of combination therapy in our country, where more than 70% of HIV infections were by homo/bisexual transmission. This confirms the transmission of drug-resistant HIV shown by genotype testing during primary infection in therapy-naive patients and initiates serious clinical and public health consequences.

Vancomycin resistant enterococci (VRE) still persist in slaughtered poultry in hungary 8 years after the ban on avoparcin.

In this report we examined the glycopeptide susceptibility of enterococci, isolated in 2005, from slaughtered animals, within the confines of Hungarian Antibiotic Resistance Monitoring System. We determined the presence of the van genes as well as their genetic relatedness in enterococci from poultry. Enterococcus sp. strains (n=175) were collected from intestinal samples of slaughtered poultry in 2005. The origin of the samples was registered at county level. After screening the strains with 30 mg vancomycin disc 19 (86%) intermediate resistant and 4 (3%) fully resistant strains were found. The distribution of minimum inhibitory concentration (MIC)-values among 23 enterococcus strains which were intermediate or resistant to vancomycin were 0.25 mg/L (4.4%), 2 mg/L (8.6%), 4 mg/L (8.6%), 8 mg/L (61%), 16 mg/L (8.6%) and 256 mg/L (8.6%). The MICs of teicoplanin were 0.25 mg/L (4.3%), 1 (8.6%), 4 mg/L (78.3%), 16 mg/L (4.3%) and 256 mg/L (4.3%). The two most vancomycin-resistant strains were vanA carriers (1 E. faecalis and 1 E. faeciuum). The farms that produced these strains can be reservoirs of VRE and the affected farms should change the technology of disinfection and breeding in order to prevent the emergence of high numbers of human VRE isolates in Hungary.

Comparison of Streptococcus mutans strains from children with caries-active, caries-free and gingivitis clinical diagnosis by pulsed-field gel electrophoresis.

A study was conducted to compare the DNA structure of Streptococcus mutans strains in children with caries-active, caries-free, and gingivitis clinical diagnosis. Twenty-eight Streptococcus mutans strains from 100 children's plaques were examined by pulsed-field gel electrophoresis (PFGE) method. The classified strains were closely related to one another, though the strains originated from different disease groups. Three identical pairs were found, but the pairs in two cases belonged to different disease groups. The results of the PFGE experiments suggest that there is no correlation between the different DNA patterns ofS. mutans strains and their cariogenecity. So the different DNA strains ofS. mutans are not the only determining factor in the development of dental caries.

Antimicrobial susceptibility of enterococci strains isolated from slaughter animals on the data of Hungarian resistance monitoring system from 2001 to 2004.

Isolates of Enterococcus spp. were collected from January 2001 to December 2004 from caecal samples of slaughtered poultry, swine and cattle in Hungary. The isolates were identified by their growth and biochemical properties and with PCR. The antibiotic susceptibility of a total number of 1272 isolates was tested with disk diffusion test to ampicillin, gentamicin, streptomycin, tetracycline, erythromycin and vancomycin. It was established that although ampicillin and amoxicillin are often used in veterinary practice its resistance rate was relatively low. In the case of tetracyclines and macrolides, a high incidence of resistance was found. Susceptibility of strains to tetracyclines and/or macrolides reduced in both 2003 and 2004 in all animal species, which may be due to the more frequent usage of these drugs in the veterinary practice following the ban of growth promoters. The annual data of vancomycin resistance point to an association between the recovery of vancomycin-resistant enterococci (VRE) isolates and the use of avoparcin. This study indicates that reducing antimicrobial resistance in food animals could be possible with lower usage of antibiotics, although variations can occur with different strains.

The first steps towards fluoroquinolone resistance in Hungarian pneumococci.

The incidence of fluoroquinolone resistance among Hungarian routine laboratory Streptococcus pneumoniae isolates, collected in 2000-2002, in common with other European countries, was very low; only 5/304 strains (1.64%) were resistant to ciprofloxacin (MIC = 4 microg/ml), and the other fluoroquinolones showed full efficacy. However, we could identify the Lys-137-Asp amino acid change, caused by a point mutation in the QRDR of the parC gene, in five strains. Additionally, we observed a definite shift in the minimum inhibitory concentrations (MICs) of all fluoroquinolones towards higher values throughout the study period. These two findings, coupled with the increasing consumption figures of fluoroquinolones, suggest that pneumococcal resistance looks poised to develop in Hungary.

Vancomycin-resistant Enterococcus faecalis colonization during recovery from Neisseria meningitidis cerebrospinal meningitis. Case report.

A 19-year-old man had been admitted to the Hospital because of septic shock and large scale suffusions all over the body. The pathogen had proved to be Neisseria meningitidis serogroup C. In his stabilization period two superinfectious attacks arose. One of them was a bacteremia, caused by a vancomycin-sensitive Enterococcus faecium. The second was a wound infection in his deep colliquating necrotised tissue of the heel. Vancomycin-resistant Enterococcus faecalis (VREF) was isolated from this lesion with some Gram-negative opportunistic pathogens. The strain contained the vanA gene. After systemic and topical treatment, furthermore plastic surgical interventions the patient recovered. This is the second report on VREF from Hungary colonizing/infecting a patient with an underlying disease.

Resistance to beta-lactams and glycopeptides in staphylococci and streptococci.

Molecular mechanisms of the action of beta-lactam and glycopeptide antibiotics, as well as genetic background and phenotypical features of the resistance of staphylococci, streptococci and enterococci to these antibiotics are reviewed. Furthermore, susceptibility patterns concerning beta-lactam and glycopeptide drugs of staphylococcal, streptococcal, as well as enterococcal strains isolated from clinical specimens at the Semmelweis University of Medicine, Budapest, Hungary between January 1997 and December 2000 are also presented.