Four years of monitoring antibiotic resistance in microorganisms from bacteremic patients.

From the second semester of 2002 to the end of the first semester of 2005, a total of 2544 bacterial strains were isolated from the blood stream of patients with clinical sepsis and bacteremia hospitalized in six University Hospitals in the Slovak Republic. Almost 30% of strains were coagulase-negative staphylococci (CONS), about 14% were Staphylococcus aureus and, of the Gram-negative bacteria, up to 9% were Klebsiella pneumoniae. All CONS, S. aureus and Enterococcus spp. strains were found to be still susceptible to vancomycin, but the resistance of CONS and/or S. aureus to macrolides and fluoroquinolones dramatically increased during the period of this study. Among Gram-negative bacteria, increasing levels of resistance to higher generation cephalosporins, to fluoroquinolones resistance in Pseudomonas aeruginosa and Acinetobacter spp. to meropenem was recorded, which is alarming. The results were periodically submitted to cooperating hospitals with proposals for rationalizing the prophylactic and general use of indicated antibiotics as well as for improving hospital hygiene measures and anti-epidemic practices.

Transferable resistance to imipenem in hospital isolates of Pseudomonas aeruginosa.

We monitored systematically, for more than five years, the eventual transferability of resistance to imipenem in strains of Pseudomonas aeruginosa isolated from patients in Frankfurt University Clinics. Quite recently, four strains have been found which transfer resistance to imipenem to recipient strains of P. aeruginosa. Although in three strains imipenem was the only antibiotic where resistance was transferred directly, the indirect selection analysis showed that, in each instance, determinants of resistance to carbenicillin and kanamycin were co-transferred. The situation in the fourth strain was more complicated. It was resistant to at least ten antipseudomonad antibiotics, and transferred directly not only determinants of resistance to imipenem, but also to carbenicillin and kanamycin, as did the other strains, plus determinants of resistance to ceftazidime and cefotaxime. The origin and mode of spread of resistance determinants in studied strains is briefly discussed.

Transferable resistance to cefotaxime in nosocomial Klebsiella pneumoniae and Escherichia coli strains due to their production of extended-spectrum beta-lactamase in Slovakia.

Transferable resistance to cefotaxime was demonstrated in 21 nosocomial strains of Klebsiella pneumoniae and Escherichia coli subsequently isolated from patients in two large University clinics. Using the double-disk diffusion test, we could detect, in each such strain, as well as in E. coli 3110 K-12 transconjugants after the transfer, the production of an Extended Spectrum Beta-Lactamase (ESBL). Ceftibuten was demonstrated to be effective against the majority of strains studied.

En bloc transduction of imipenem resistance with other resistance determinants from a clinical strain of Pseudomonas aeruginosa.

In this report we describe a lysogenic strain of Pseudomonas aeruginosa No. 229, from Frankfurt University Clinics, resistant to imipenem (IMI), cefotaxime (CTX), kanamycin (KAN), carbenicillin (CAR) as well as to other non-beta-lactam drugs, from which a wild-type phage could be isolated and used for transduction of an imipenem resistance determinant. All IMI-selected transductants were found to be co-resistant also to CTX, KAN and CAR. Conversely, transductants selected with CTX, KAN or CAR were also all resistant to IMI. It seems probable that IMI is hydrolyzed by the original donor strain as well as by transductant colonies by means of a clavulanate-inhibited beta-lactamase and not by a metallo-beta-lactamase.

Monitoring of antibiotic resistance in bacterial isolates from bacteremic patients.

The aim of the study was to monitor the prevalence of pathogens and development of resistance in bacteria isolated from bacteremic patients. Five University Clinics and/or Regional Hospitals in the Slovak Republic participated in the study and a total of 421 isolates were collected in the second half of the year 2002. The most prevalent organisms were coagulase-negative staphylococci (CONS) (19%), Staphylococcus aureus (18.3%), among Gram-negative bacteria Escherichia coli (13.3%), Klebsiella pneumoniae (11.4%) and Pseudomonas aeruginosa (7.8%) followed by enterococci, Acinetobacter baumannii and Enterobacter sp. All CONS and S. aureus were susceptible to vancomycin; resistance to oxacillin was observed for 55% of the CONS and only for 4% of S. aureus isolates. A higher prevalence of resistance to erythromycin, clindamycin, gentamicin and ofloxacin was found in CONS in comparison to S. aureus. Enterococcus sp. isolates were fully susceptible to vancomycin and teicoplanin. Gentamicin, amoxicillin/clavulanate, third generation cephalosporins and ciprofloxacin showed good activity against E. coli. Although 17% of K. pneumoniae isolates were resistant to ciprofloxacin, it was the most effective drug against K. pneumoniae; the prevalence of resistance to other antibiotics was rather higher. Gentamicin and ciprofloxacin were the most active against Enterobacter sp. isolates and ceftazidime and meropenem against P. aeruginosa.

Transduction of resistance to Imipenem, Aztreonam and Ceftazidime in nosocomial strains of Pseudomonas aeruginosa by wild-type phages.

Two wild-type bacteriophages, designated AP-2 (for P. aeruginosa phage) and AP-12, have been isolated and propagated from two multiple drug resistant strains of P. aeruginosa. Both phages were found to transduce Imipenem- (IMI), Aztreonam- (AZA) and Ceftazidime- (CTZ) resistance as well as resistance determinants to other drugs. Genetic analysis showed that resistance determinants to newest anti-pseudomonal antibiotics IMI, AZA and CTZ could be separated by transduction. Thus the resistance to these antibiotics is presumably coded by different genes. In some transductans also the presence of the tra+ has been demonstrated, indicating that they can transfer the resistance to other strains by conjugation.

[Transposons coding beta-lactamase with an extended spectrum of effects and resistance to other antibiotics]. / Transpozóny kódujúce beta-laktamázy s rozsíreným spektrom úcinku (ESBL) a rezistenciu na d'alsie antibiotiká.

The authors present contemporary knowledge concerning the transposition of resistance genes to penicillins, cephalosporins and carbapenems, and transposons and integrins coding resistance to other antibacterial substances. Transposition is, together with bacterial conjugation and transduction with bacteriophages, another mechanism of mobility and restructuring of resistance genes in bacterial strains of the same and also in other bacteria.

[Transfer of resistance to 3rd generation cephalosporins and aztreonam in strains of Klebsiella pneumoniae producing extended spectrum beta-lactamases]. / Prenosná rezistencia na cefalosporíny 3. generácie a aztreonam u kmenov Klebsiella pneumoniae produkujúcich beta-laktamázy s rozsíreným spektrom úcinku (ESBL).

The authors demonstrated the transferability of antibiotic resistance genes in nosocomial strains of Klebsiella pneumoniae, isolated from newborn children at the Paediatric University Hospital in Bratislava. Strains were resistant to cefotaxime, ceftazidime and aztreonam. The determinants of resistance (carbenicillin, cephaloridine, cefotaxime, ceftazidime and aztreonam) were transferred to recipient strains of Escherichia coli K-12 and Proteus mirabilis P-38. The transfer of resistance determinant from donor strains was demonstrated by the analysis of the resistance spectrum in transconjugant clones of recipient strains by the method of indirect selection. The ability of production of extended spectrum beta-lactamases (ESBL) was demonstrated by the double disc diffusion test. Synergy between clavulanate and cefotaxime, clavulanate and ceftazidime and/or clavulanate and aztreonam indicated production of ESBL by these strains.

[Mobilization of genetic determinants of antibiotic resistance in strains of Pseudomonas aeruginosa]. / Mobilizácia genetických determinantov rezistencie na antibiotiká u kmenov Pseudomonas aeruginosa.

The authors describe a phenomenon of mobilisation of antibiotic resistance from non-transferring strains of P. aeruginosa by cultivation with strains of P. aeruginosa capable to transfer determinants of antibiotic resistance to a susceptible recipient strain, by triparental cross. In this report three strains of P. aeruginosa (No. 282, 283 from Bata's Hospital in Zlín and 76 from Frankfurt University Clinics) are described capable to mobilise for transfer the resistance determinants in four strains of P. aeruginosa (No. 76, 229, 47 and 125 from Frankfurt University Clinics) with multiple antibiotic resistance which itself was not transferable to recipient strains. By an indirect selection method it was assessed, that all six antibiotics (cephalotin-cefazoline, carbenicillin, kanamycin, cefotaxime, ceftazidime and aztreonam), present in resistance spectrum of intermediary recipient strains, were mobilised for transfer. Imipenem and ofloxacin were not mobilised for transfer. In the second and third cycles of transfer the authors confirmed the stability and transferability of the block of six antibiotic resistance determinants, which were not previously transferable.

[Peroral preparations of cephalosporin antibiotics]. / Perorálne preparáty cefalosporínových antibiotík.

Three successful generations of cephalosporin antibiotics can be divided into parenteral and peroral substances. Both have similar antibacterial and hence therapeutical properties. It is usual to include into the first generation of peroral cephalosporins the so-called phenylglycine, or hydroxyphenylglycine derivatives. The carbacephem variant of Cefaclor (Panoral Lilly), Loracarbef, however, has improved properties and although it is a phenylglycine drug, it could be classified as a second generation cephalosporin. Here we include also the so-called ester-prodrugs: 2nd generation parenteral cephalosporins esterified in the position of C4 (cefuroxime-axetil, Zinnat, cefpodoxime-proxetil, Oralox, etc.). They are broad-spectrum antibiotics, not hydrolysed by resistant bacteria, and, hence, they are effective also against cephalosporin-(1. generation) resistant strains. New structures of cephalosporins, e.g. cefixime and ceftibuten (Cedax) could be classified as cephs of the 3rd generation. They, are stable even against destruction by strains resistant to Cefotaxime or Ceftazidime, and, thus, effective against such bacteria, whose number is expected to increase in the near future. It is concluded that the possibility to administer cephalosporins having different properties, spectrum and stability by both parenteral and peroral way is highly welcomed mainly in pediatric practice and that there are several new and promising drugs in this still developing group of antibacterials.

[Variation in transfer resistance to cefotaxime, ceftazidime and aztreonam in strains of Acinetobacter sp., Enterobacter sp. and Citrobacter sp. isolated from the same university hospitals]. / Diferenciálna transferabilita rezistencie na cefotaxím, ceftazidím a aztreonam u kmenov Acinetobacter sp., Enterobacter sp. a Citrobacter sp. izolovaných z tých istých univerzitných nemocníc.

BACKGROUND: In the last decade were in SR documented new problems in resistance to the newer antibiotics that with regard to their structure and antibacterial properties resisted to the known mechanism of bacterial resistance. The emergence of multiple drug resistance to the new betalactams is connected both with frequent application of these drugs in the hospitals and transfer of R plasmids. METHODS AND RESULTS: We studied composition and transferability of resistance to newer betalactam antibiotics in strains of Acinetobacter sp., Enterobacter sp, and Citrobacter sp. isolated during one month in patients from two teaching University Hospitals. All strains studied were resistant to cefotaxime (CTX), ceftazidime (CAZ) and aztreonam (ATM) but Acinetobacter strains, although resistant also to CAZ and ATM transferred the resistance to CTX only. Thus, resistance to CAZ and ATM has a chromosomal origin in these strains. A strain of Citrobacter sp., resistant to CTX, CAZ and ATM, produced a ESBL betalactamase detectable in a double-disk diffusion method (Fig. 1). An Enterobacter cloacae strain transfers directly the resistance to all new betalactams indicated. Their hydrolysis by these strains points to their production of new types of extended-spectrum beta-lactamases ESBL). CONCLUSIONS: We strongly recommend to be strictly rational in the use of new betalactams of CTX, CZA or ATM type because it is suspected that, especially in so-called empirical prophylaxis or treatment, they exert a strong selective pressure toward the prevalence of mutants with transferable ESBL-producing nosocomial bacteria resistant to these drugs.

[A review of new cephalosporin antibiotics]. / Prehlad novsích cefalosporínových antibiotík.

The authors discuss some properties of recent cephalosporin antibiotics and the antibiotics effectiveness in particular of more recent generations of cephalosporins. The increasing resistance to penicillins and other antibiotics called for use effective cephalosporins of new generations. While cephalosporins of the 1st generation (cephalothin, cephazoline, and oral cephaloridine or cephaclor) are effective against Gram-positive bacteria, haemophilus bacteria and Klebsiellae, the resistance of other bacteria even against these antibiotics is increasing. Mephoxine and cephuroxime belong to the 2nd generation as their spectrum of efficiency is wider. Cephalosporins of the 3rd generation (cefotaxime, ceftriaxone, ceftazidime and others) are effective only against strains resistant to cephalosporins of the older generations. Oral preparations of cephalosporins of recent generations (Loracarbef, cefpodoxim, ceftibutene) are also useful.

[Experience with individual corticosteroid therapy of bronchial asthma in middle-aged and elderly patients (controlled by monitoring of blood tyrosine level)]. / Opyt individualizatsii terapii kortikosteroidami u bol'nykh bronkhial'noi astmoi pozhilogi i starcheskogo vozrasta (pod kontrolem soderzhaniia tirozina v krovi).

Blood level of tyrosine as a new clinical and laboratory indicator has been studied in bacterial asthma patients of advanced age. Tyrosine is known to affect metabolism of glucocorticoid hormones (GHs) thus reflecting GHs status of the body and permitting valid evaluation of the need in corticosteroid therapy.

[Transmission of resistance to 1st and 2d generation cephalosporins]. / Prenosná rezistencia na cefalosporíny 1. a 2. generácie.

The authors investigated the incidence of transferable resistance in bacterial strains resistant to cephalosporins of the first and second generation in the course of two years in materials of the microbiological department of one of the larger district hygiene stations. They recorded the development of the first strains resistant also to cephamandol, although this antibiotic is not used at all in the above area, and in exceptional instances also resistance to cephotaxime. It was revealed that the transferable resistance to cephamandol is due to the presence of an enzyme which hydrolyzes this antibiotic. When using cephalosporins of the first generation, it is important to foresee an increasing incidence of transmitted resistance to these antibiotics and possibly some strains resistant also to cephalosporins of the second generation and in exceptional cases strains resistant to cephalosporins of the third generation.

A bi-modal transfer of antibiotic resistance by conjugation and transduction from an imipenem-resistant strain of Pseudomonas aeruginosa.

A strain of Pseudomonas aeruginosa No. 76/17224 resistant to carbenicillin (CAR), kanamycin (KAN), cefalotin (CLO), cefotaxime (CTX), ceftazidime (CAZ), aztreonam (AZA), imipenem (IMI) and ofloxacin (OFL) was isolated at the Frankfurt University Hospital. This strain transferred, by conjugation, antibiotic resistance determinants to CAR, CLO, CTX, CAZ and AZA. In addition, we isolated a wild-type phage from this strain. We used this phage to transduce the resistance determinants to four susceptible recipient strains of P. aeruginosa. The phage designated AP-76 transduced the resistance determinants to KAN, CAR, CTX and CAZ to all four recipient strains. Imipenem and aztreonam resistance determinants were directly transduced to two recipient strains only, i.e. to PAO-1670 and ML-1008. The IMI resistance determinant was not co-transduced with any other resistance determinant(s) selected directly. Our results indicated that IMI resistance determinant was not associated with other resistance determinants. IMI was actively hydrolysed by IMI-resistant transductants and this hydrolysis was inhibited by clavulanate but not by EDTA.