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.

Use of the BIOMIC Video System to evaluate the susceptibility of clinical yeast isolates to fluconazole and voriconazole by a disk diffusion method.

The ARTEMIS Global Antifungal Susceptibility Program provides the collection of epidemiological data and the results of the fluconazole and voriconazole susceptibility testing of yeast isolates. Participating in this study, a total of 7318 clinical yeast isolates were tested from different geographical areas in Hungary in the period 2001 to 2003. The species isolated most frequently was C. albicans (68.8%), followed by C. glabrata (11.8%), C. tropicalis (5.7%) and C. krusei (4.6%). Isolates of C. albicans, C. kefyr, C. lusitaniae, C. tropicalis and C. parapsilosis were highly susceptible to fluconazole (78.9-100%). The rates of isolation of fluconazole-resistant C. glabrata and C. krusei were higher in our study than the global mean in 2001 (28.2% and 87.5% vs. 18.3% and 70.2%, respectively). Differences were detected in the distribution of fluconazole-susceptibility data of C. glabrata isolates in the different counties of Hungary: most of the resistant isolates were observed in the eastern part of the country.

Extended-spectrum beta-lactamases: an actual problem of hospital microbiology (a review).

Although there is a variety of mechanisms of bacterial resistance to beta-lactam antibiotics, the most important one is production of beta-lactamases inactivating penicillins and cephalosporins. The classification of beta-lactamases is based on biochemical, enzymological (i.e. molecular structure, inhibitory property, substrate-profile, relative rate of hydrolysis) and immunological characters. Extended-spectrum beta-lactamases (ESBLs) can be derived from TEM or SHV enzymes. These enzymes have now been sequenced and it has been found that relatively few point mutations have occurred in the gene of the TEM and SHV type enzymes. These point mutations clustered in five areas of the gene. The amino acid mutations can alter the conformation, the active site and change the hydrance of beta-lactamase-cephalosporin binding capacity. So the enzyme is able to bind and hydrolyse the third generation cephalosporins. Successive mutation interacted radically increasing the binding capacity of enzymes and confer resistance to newer cephalosporins. The use of these drugs provides a strong selective pressure to develop these mutations. Sporadic nosocomial outbreaks due to strains producing an ESBL led to an epidemic problem in some hospitals resulting in a concurrent dissemination of genes, plasmids or strains. Clinical epidemiological importance and role of ESBLs and emergence of multiply resistance of bacteria of nosocomial importance are discussed in this brief.

Genotypic and phenotypic characters and nosocomial significance of bacteria endemic in neonatal intensive care units.

The degree of colonization was determined by complex typing (sero-, phage, colicin-, pyocin typing, plasmid profile analysis) of 212 Escherichia coli, 232 Klebsiella, 117 Pseudomonas aeruginosa and 52 Staphylococcus aureus strains isolated from nose, throat, ear and other sources of 563 new-born infants in gynaecological and maternity wards of two neonatal intensive care units (NICU I and II) during a one year period. The presence of Klebsiella strains was more frequent in NICU I and E. coli and P. aeruginosa in NICU II, S. aureus occurred in a low level in both units. In NICU I 34 kinds, in NICU II 43 kinds of E. coli serotype were found. In NICU I the accumulation of serotypes O6:H-, O6:H1, O19:H-, in NICU II O4:H-, O6:H1 was observed. The Klebsiella strains belonged in NICU I into 21, in NICU II into 12 phage types. Klebsiella was more frequent in NICU I than in NICU II, though the strains belonged to the same phage type in NICU II in 50.7%, but in NICU I 4 frequent and 19 rare phage types occurred. Sero- and pyocin typing was effective for typing of P. aeruginosa. The most frequent sero- and pyocin types were in NICU I:O11a,11b; in NICU II: O2a,2d,2f; 12v. The rate of antibiotic resistance in E. coli, Klebsiella, P. aeruginosa and S. aureus was nearly the same in both units, multiple resistance was more frequent in NICU I (except P. aeruginosa, it was multiple resistant in 100% in both units). In NICU I 267, in NICU II 174 infants were treated with antibiotics. The administration of penicillin derivatives was nearly similar in the two care units and the resistance among E. coli and Klebsiella strains was nearly the same too. Though, cephalosporins were used more frequently in NICU II, resistance to cephalosporins among E. coli and Klebsiella was a bit higher in NICU I. Aminoglycosides were more often used in NICU I, resistance to aminoglycosides among E. coli and Klebsiella was higher in this unit. The rate of isolation of the examined bacteria was significantly lower in the group treated with antibiotics, than in the untreated group.

Typing of coagulase-negative staphylococci isolated from immunocompromised patients.

A total of 3121 coagulase-negative staphylococcal strains sourced from clinical samples were characterized during a 4-year period. Biotype, antibiotic resistance pattern, phage pattern and slime production was determined. Plasmid profile analysis was performed on related isolates. Thirty percent of strains originated from the Bone Marrow Transplantation Unit, The National Institute of Haematology, Blood Transfusion and Immunology (NIHBTI), Budapest. Staphylococcus epidermidis occurred most frequently (48.8% in total, 58.2% source from NIHBTI). Total bacteriophage typability was 75.9%, and 603 phage patterns were observed. NIHBTI isolates differed in the incidence of multiply resistance, slime positivity and average frequency of phage patterns from the total suggesting spread of a selected hospital population. Statistical analysis of data obtained by typing showed no predominance of any endemic clone: the strains colonizing the immunocompromised patients and isolated from staff and inanimated environment differed from each other in biotype, phage pattern, antibiotic susceptibility, slime production and/or plasmid profile.

Different kinetic of enzymatic inactivation of lincomycin and clindamycin in Staphylococcus aureus.

Lincosamide inactivation nucleotidylation (Lin) enzyme determined by the pBI109PGL plasmid of Staphylococcus epidermidis exhibits high level resistance to lincomycin but sensitivity to clindamycin by standard susceptibility methods. Substrate profile determination showed clindamycin to be a better substrate for the enzyme than lincomycin. In cultures of the plasmid-harboring strain, the level of clindamycin decreased below the inhibitory concentration in the first 4 hours of incubation but the level of lincomycin persisted longer. The initial extended inhibitory effect of clindamycin is due to better membrane penetrating ability, resulting in a higher intracellular concentration than that of lincomycin. Moreover, energy-dependent reduction in clindamycin uptake, probably due to active efflux of clindamycin but not of lincomycin, was observed. A therapeutic effect of clindamycin is not expected in infections caused by Lin-producer strains because the bacteriostatic effect of the drug is rapidly eliminated after administration.

Phage pattern and antibiotic resistance pattern of coagulase-negative staphylococci obtained from immunocompromised patients.

A total of 152 coagulase-negative staphylococcal strains were isolated from clinical samples of 14 patients hospitalized after bone-marrow transplantation in a specialized hospital ward in Hungary, during an 18-month period between 1987 and 1989. Two species, Staphylococcus epidermidis and Staphylococcus haemolyticus, predominated (each, 45%). Using Pulverer and co-workers' phage set for typing, 68% of the isolates were typable; 16 phage patterns were observed. A characteristic long pattern with phages Ph10/Ph13/Ph15/U4/U15/U16/U20/U33 /U46 appeared only in S. epidermidis, among 5 of 11 colonized patients (8.5% of all strains). Single lysis with phage Ph13 was observed in 7 of the 14 patients (49% of all strains), in species S. capitis, S. epidermidis, S. haemolyticus, S. hominis, and S. warneri. In S. haemolyticus, non-typable strains predominated (66%); this character occurred only in 2% among other species. The strains colonizing the immunocompromised patients differed from each other in phage pattern, antibiotic resistance pattern, and/or slime production. No hospital infection was suggested. On the other hand, high incidence of two well-definable phage patterns raises some relationship between phage receptors or some regulatory systems in phage multiplication and factors responsible for special colonization as common surface properties.

Plasmids encoding for erythromycin ribosomal methylase of Staphylococcus epidermidis and Staphylococcus simulans.

Two 1.7 Md plasmids of Staphylococcus epidermidis and three ones of Staphylococcus simulans determining inducible macrolide-lincosamide resistance are identical as judged by restriction endonuclease fingerprinting. These plasmids designated pEI2101, pEI9105, pE1107, pEI1108 and pEI6104, respectively, belong to the incompatibility group 12. Dot-blot hybridization by photobiotin-labelled gene probe developed from S. aureus erythromycin ribosomal methylase gene showed cross hybridization between methylase-coding reference plasmids and the tested ones. The examined plasmids proved to be no transmissible in mating experiments into S. aureus recipients.

Plasmids determining enzymatic inactivation of lincomycin in Staphylococcus epidermidis. A preliminary report.

Coagulase-negative staphylococcal strains isolated from immunocompromised patients harboured in 41% non-MLS type lincomycin resistance determinant. Two kinds of resistance plasmids were detected in Staphylococcus epidermidis isolates of this origin in connection with lincomycin resistance. One of them represented by pBI1 and pBI84 (1.4 Md in size) determines no other resistance marker. The pBI109PGL plasmid determines also penicillinase production and aminoglycoside resistance, its molecular mass is 31 Md. Hybridization using linA, linA' and linA-like specific gene probes suggested occurrence of genes of lincosamid-inactivating enzyme belonging to the lin gene family but differring from the previously characterized determinants.

Complex typing of Pseudomonas aeruginosa strains isolated in an intensive care unit [a note].

A total of 2637 Gram-negative facultatively pathogenic bacteria were isolated in the László Central Hospital for Infectious Diseases during a 5-year-period from clinical samples of patients of the Respiratory Intensive Care Unit; 28 further strains were cultured from hospital personnel and fomites. Pseudomonas aeruginosa, Klebsiella and Acinetobacter spp. were most frequently isolated. Complex typing (determination of O serogroup, phage pattern, pyocin type, antibiogram and plasmid pattern) of P. aeruginosa strains showed the predominance of serogroup O11 (62%), but the isolates differed from each other by other characteristics. Conjugation experiments showed no common resistance plasmids in the tested population.

[Antibiotic resistance of gram-negative bacteria isolated at a hospital intensive care unit]. / Kórházi intenzív osztályon izolált gram-negatív kórokozók antibiotikum rezisztenciájának alakulása.

The antibiotic sensitivity of Gram-negative facultatively pathogenic bacteria isolated between 1982-1986 in the respiratory intensive care unit of the 3rd department of pediatry of the "László" Hospital (Budapest) has been studied. Pseudomonas aeruginosa, Klebsiella, Acinetobacter calcoaceticus and Acinetobacter lwoffii were most frequently isolated both from the clinical samples (total 56.9%) and in samples obtained from hospital-hygienic check-examinations. 70-100% of the individual species was resistant to antibiotics used in Hungary. The gentamicin and tobramycin resistance of P. aeruginosa and A. lwoffii showed significant rate of increase. Favourable in vitro results were obtained only with ceftriaxon, ceftazidime, netilmicin and amikacin.

Clinical occurrence and virulence testing of coagulase-negative staphylococci.

A total of 650 coagulase-negative staphylococcal strains of miscellaneous clinical origin were isolated and identified during a 7-year-period. In all kinds of samples Staphylococcus epidermidis was the most frequently found species. In wounds the incidence of haemolytic species (S. cohnii, S. epidermidis, S. haemolyticus, S. simulans, S. warneri) was 79.3%. Among strains derived from male genitals (urethra, semen, etc.) S. epidermidis and S. simulans predominated. Only 8.2% of the strains were found not to harbour resistance determinants, while 63% proved to be multiply resistant. Only the incidence of resistance to oxacillin and first and second generation cephalosporins was low (12.8, 14.9 and 4.5%, respectively). Vancomycin was the only drug effective against all strains. Extracellular slime was produced by 42.2% of the strains. The frequency of slime-positivity among isolates causing clinical infection was twice as high as among contaminations. Slime production seems to be a stable characteristic of the isolates. The comparison of two methods used for detection of slime factor showed that incubation in test tube in Tryptone Soya Broth, or its application to microtiter plates evaluated by photometry are of equal diagnostic value.

Binding of lincomycin to immunoglobulins has no effect on their antigen-binding capacity.

The interaction of lincomycin and immunoglobulins was examined in vitro. While lincomycin bound to the immunoglobulin molecules seemed to decrease the quantity of IgG and IgM detected by radial immunodiffusion and microzone electrophoresis, the level of specific antibodies could not be demonstrated by enzyme-linked immunosorbent assay (ELISA).

Resistance plasmids for inducible macrolide-lincosamide resistance in Staphylococcus simulans and Staphylococcus epidermidis.

Localization and genetic nature of inducible macrolide resistance determinants in some coagulase negative staphylococci (CNS) were studied and compared with those in Staphylococcus aureus. An 1.7-megadalton R-plasmid, pEI 1107, mediating inducible resistance to macrolides and lincosamides was present in part of Staphylococcus simulans and Staphylococcus epidermidis strains isolated in the Central Hospital for Infectious Diseases. Two other plasmids were harboured by S. simulans LK 6108 strain. One of these plasmids, pEI 6108 (molecular mass 5.2 Md) was encoded for inducible macrolide-lincosamide resistance, and the second one, pE 6108 (molecular mass 4.9 Md) for constitutive marcolide resistance. The similarity in size and phenotype of small plasmids in CNS and S. aureus suggest a common origin of these resistance determinants.

Possible role of lincomycin-therapy in the genetic alteration of a staphylococcus epidemic population.

In a staphylococcosis epidemic occurring in a child community, the proportion of inducible lincomycin resistance has risen significantly in the bacterium population. This conveyed the possibility that lincomycin or its derivatives may induce a lincomycin resistance in Staphylococcus aureus as it is already known in streptococci. Examination of human and animal samples obtained during lincomycin treatment showed that lincomycin had no role in the induction of resistance; the agent can effectively be applied against pathogens of the above-mentioned phenotype. Immunological examination of serum samples provided opportunity for a more exact localization of the protein-linkage of lincomycin.