Genetic typing of Enterococcus faecium VRE strains isolated in three hospitals in Warsaw and Siedlce in 2015-2016

INTRODUCTION

Since the first report of vancomycin-resistant enterococci (VRE) in Poland, in 1996, these strains have spread in Polish hospitals, mainly due to selective pressure associated with increased use of vancomycin in the treatment of infections caused by methicillin-resistant staphylococci and Clostridium difficile. At the beginning of 2016 a growing number of patients colonized with VRE in the gastrointestinal tract was observed in the Children’s Memorial Health Institute (IPCZD). Some of these patients were transferred from other hospitals, and VRE colonization was found on admission.

AIM

To analyze genetic similarity of VRE strains isolated from patients hospitalized in IPCZD and two other hospitals in Mazovian district, genetic typing by pulsed field gel electrophoresis (PFGE) was performed.

MATERIALS AND METHODS

VRE strains were isolated from rectal swabs, and other clinical samples such as blood, cerebrospinal fluid, other body fluids, and environmental samples. A total of 56 VRE strains from IPCZD, 20 strains from Siedlce and 4 strains from patients from Grochowski Hospital in Warsaw were typed by PFGE.

RESULTS

PFGE typing revealed 4 VRE clones containing several strains with identical restriction patterns. Among VRE strains isolated from neonates hospitalized in IPCZD, two clones with 24 and 20 identical strains were found. Respectively, 16 (67%) and 12 (60%) isolates were originated from rectal swabs from patients at admission to the hospital. Clonal strains were identified in all three hospitals included in the study.

CONCLUSIONS

Our results showed that VRE strains had spread in the region. Isolation of clonal strains on admission to the hospital suggested independent VRE introductions from environment or other hospitals. Identification of clonal strains obtained from rectal swabs and other clinical samples during hospitalization indicated horizontal transmission.

Molecular Epidemiology and Drug Resistance of Acinetobacter baumannii Isolated from Hospitals in Southern Poland: ICU as a Risk Factor for XDR Strains

The objectives of the present study were to investigate the carbapenemase and metallo-beta-lactamase genes of Acinetobacter baumannii clinical isolates by polymerase chain reaction (PCR) and real time PCR and to determine the molecular epidemiology of the strains using the DiversiLab tool. From these data, correlations between drug resistance, resistance genes, and epidemiological clones may be revealed. The study was conducted on 125 A. baumannii collected over the 2013 year. The majority of the isolates from both intensive care unit (ICU) and non-ICU cases originated from pneumonia infections (79.2%), isolates from blood infections accounted for 17.6% and 3.2% were from meningitis infections. In the ICU cases compared with the non-ICU cases, bloodstream infections were more frequently diagnosed (19.2% vs. 11.5%). Sixty percent of A. baumannii strains were resistant to all the antimicrobials tested with the exception of colistin. All strains were susceptible to colistin and polymyxin B. Extensively drug-resistant (XDR) strains accounted for 80.8% of the isolates tested and these XDR strains were more frequently isolated from ICU cases than from non-ICU cases (93.9% vs. 30.8%). Among the 101 isolates of A. baumannii exhibiting the XDR pattern of resistance, 80 possessed the blaOXA-24 gene and 29 had the blaOXA-23 gene. Only two isolates possessed the blaVIM gene. The presence of the ISAba1element was confirmed among 10 strains from patients hospitalized in the ICU. Using repetitive extragenic palindromic sequence PCR (DiversiLab typing), six clones and 12 unique strains were identified, of which two clones dominated. Most isolates belonging to clone 1 (66.7%) and clone 2 (85.5%) were susceptible only to colistin. In summary, it is clear from our findings and those of other studies that carbapenem resistance among A. baumannii strains presents a serious clinical problem worldwide. Furthermore, the presence of XDR international clone II in ICUs poses a potential risk for future outbreaks of A. baumannii infection and controlling A. baumannii infections in hospitals presents a serious challenge.

[Epidemiologic analysis of increased frequency of isolation of multidrug-resistant Acinetobacter sp. using PFGE technique]

From November 2007 to November 2008, 25 multidrug resistant Acinetobacter baumanii/haemolyticus strains were isolated from 21 patients treated in the Pulmonary Diseases and Tuberculosis Hospital in Bystra. Seven cases were regarded as nosocomial infections. Most of the patients were hospitalized several times and/or admitted from other hospitals. The aim of this study was to find the reason for increasing colonization and infections with this microorganism. PFGE analysis showed high, exceeding 90% relationship among tested strains suggesting their clonal spread among patients in several hospitals in our region. Despite excessive search, no environmental reservoir of Acinetobacter was found, so cross-contamination via staff's hands was suspected the most likely source of this spread. Therefore, hand hygiene and contact isolation seemed the most relevant infection control measures.

[Phenotype and genotype characterization of Candida albicans strains isolated from patients hospitalized at the Children's Memorial Health Institute]

Phenotype and genotype analysis was prepared from Candida strains causing colonization and fungal infections in children hospitalized at The Children's Memorial Health Institute intensive care unit and oncology unit. We totally analyzed 117 C. albicans strains cultured from different clinical specimens received from 51 patients--oncology unit (26) and intensive care unit (25). Enzymatic activity was assessed by API ZYM bioMerieux. Strains were biotyped according to Williamson, Kurnatowska and Kurnatowski classification. Candida albicans isolates were RAPD typed. C. albicans strains causing colonization and fungal infections on those units released such enzymes like esterase lipasis, waline arylamidasis and phosphohydrolasis. The most frequent biotypes in group of patients oncological unit with fungal infections were biotype E (64.7%) and biotype C (26.6%) while in group of patients with colonized mucosa dominated biotypes: E (28.6%) and A (28.5%). Comparing with intensive care unit group patients, the most frequent biotype isolated among patients with fungal infection symptoms was biotype E (71.7%), while in mucosa colonization group C (35.5%) occurred as a dominating biotype. This study demonstrated clonal character of fungal infections among patients hospitalized in two units and considerable polymorphism among yeast strains: 23 pattern stripes in oncology unit and 28 pattern stripes in intensive care unit. What is more, yeast biotype determination allows showing frequent occurrence of virulence character of isolates received from infected patients in comparison with those received from colonized patients.

[Antimicrobial drug resistant pathogens in nosocomial urinary tract infections--selected aspects]

The article discusses the etiology of hospital urinary tract infections focusing on spread of antimicrobial-resistant pathogens. It also describes the most important biochemical and genetic mechanisms of resistance to beta-lactams, aminoglycosides and fluoroquinolones among hospital isolates.

Pseudomonas aeruginosa strains harbouring an unusual blaVIM-4 gene cassette isolated from hospitalized children in Poland (1998-2001)

OBJECTIVES

During 1997-2001, 151 isolates of imipenem-resistant Pseudomonas aeruginosa were obtained from clinical specimens taken from children hospitalized in Warsaw, Poland. These strains were investigated further to determine the mechanism of resistance.

METHODS

The strains were analysed by a combination of genotyping and PCR-based strategies.

RESULTS

Eleven of these strains were found to contain the metallo-beta-lactamase (M beta L) gene bla(VIM-4). The first strain appeared in 1998, and P. aeruginosa strains harbouring this M beta L have become endemic in this hospital since then. All P. aeruginosa strains belonged to serotype O:6, and PFGE analysis revealed four different patterns and three sub-types. All 11 M beta L-producing strains contained an identical class 1 integron with the usual 5' and 3' conserved sequences. The integron included two resistance cassettes, aacA4 in the first position and the bla(VIM-4) cassette in the second position. The bla(VIM-4) gene included an unusual direct repeat of 169 bp of the 3' portion of the bla(VIM-4) gene.

CONCLUSIONS

An unusual bla(VIM-4) M beta L has become endemic in P. aeruginosa isolates infecting Polish children hospitalized on surgical wards. The formation of this unusual bla(VIM-4) gene cassette could be explained by a mechanism involving deletion of a segment of an ancestral tandem repeat of bla(VIM-4) via slipped strand replication, mediated by a combination of polymerase and integrase.

Urinary tract infections caused by endemic multi-resistant Enterobacter cloacae in a dialysis and transplantation unit

In the period 1994-1998, 42 multi-resistant Enterobacter cloacae isolates responsible for urinary tract infections (UTIs) were obtained from children hospitalized in our dialysis and transplantation unit. E. cloacae isolates obtained between 1994 and 1996 were susceptible to aminoglycosides, carbapenems and fluoroquinolones, whereas E. cloacae isolates obtained between 1997 and 1998 were susceptible to carbapenems and fluoroquinolones, only. All isolates were characterized by use of the polymerase chain reaction-based random amplification of polymorphic DNA and pulsed-field gel electrophoresis. It was found that the majority of multiresistant E. cloacae isolates obtained during 1997-1998, and all isolates obtained during 1994-1996, belonged to predominant clones A or B. These strains were responsible for gastrointestinal tract colonization and UTI of renal transplant recipients for several years, and persisted as endemic E. cloacae strains in the dialysis and transplantation unit from 1994 to 1998.