Varicella-zoster virus infection in the pediatric population with acute lymphoblastic leukemia in Poland.

Varicella-zoster virus (VZV) infection in pediatric hemato-oncology patients can be a therapeutic problem when children are exposed to immunosuppression. The aim of this study is to evaluate the incidence of VZV infection, antiviral therapy and outcome in children with ALL treated in polish hemato-oncological centers between 2012 and 2019 years. This study included medical records of 1874 patients, aged 1 to 18 years, with newly diagnosed acute lymphoblastic leukemia. During chemotherapy, 406 children out of 1874 (21.6%) experienced viral infections. The incidence of VZV infection in the whole group children with ALL was 1.8%. Among them, 34 (8.4%) patients were diagnosed with VZV infection. Thirty-five episodes of viral infections were identified. The median time of VCV therapy was 12 days. Herpes zoster infection occurred in 24 (70.6%) children, and varicella in 10 (29.4%) ones. The average time from the start of chemotherapy to the appearance of herpes zoster was 7.26 ± 4.05 months. VZV infection occurred mainly during the maintenance therapy, the reinduction and induction phases. There was no correlation between steroid dosage or type and subsequent zoster. The total lymphocyte count of these patients on the first day of zoster was reduced. No serious complications were observed due to this infection. All patients survived. In conclusion, a low incidence of VZV infection was observed among pediatric patients with ALL in Poland. This analysis indicates that currently used therapeutic methods are effective in children with cancer and VZV infection. The main focus should be on the prevention of delayed chemotherapy.

Infectious profile in children with ALL during chemotherapy: A report of study group for infections.

INTRODUCTION: The treatment-related mortality in currently published studies of acute lymphoblastic leukemia (ALL) in children is 2-4%, mainly due to infections. The aim of the study was to analyse the incidence, epidemiology, profile of infection and the death rate in children with ALL. PATIENTS AND METHODS: The retrospective analysis included 1363 patients, aged 1-18 years, with newly diagnosed ALL, who were treated in 17 pediatric hematology centers between 2012 and 2017 in Poland. The patients received therapy according to the ALL IC-BFM 2002 and 2009 (International Berlin-Frankfurt-Munster Study Group) protocols. RESULTS: In our study, 726 out of 1363 (53.2%) children were reported to have a microbiologically documented bacterial infection during chemotherapy. 1511 episodes of these infection were diagnosed. A total number of 251/1363 (18.4%) children experienced a viral infection. 304 episodes were documented by PCR test (polymerase chain reaction). A fungal infection was reported in 278 (20.4%) children, including 10.1% of probable, 6.0% of proven, 83% of possible diagnosis. A higher frequency of fungal infection was noted in the recent years. In our material, the rate of death was 2.4%, mainly due to fungal infection. CONCLUSIONS: Our results present the epidemiology of infectious disease in the Polish ALL patient population. The most frequent were bacterial infections, followed by fungal and viral ones. Similar to the previously published data, the mortality rate in our material was 2.4%.

Infections with Klebsiella pneumoniae in Children Undergoing Anticancer Therapy or Hematopoietic Cell Transplantation: A Multicenter Nationwide Study.

Background:Klebsiella pneumoniae is a nosocomial pathogen that causes severe infections in immunocompromised patients. The aim of the study was to conduct a microbiological and clinical analysis of K. pneumoniae infections in children with malignancies or undergoing hematopoietic cell transplantation in Poland. Methods: We conducted a retrospective, multicenter study including children and adolescents under 19 years old treated between 2012 and 2021. We analyzed patients' characteristics, microbiological data, and the outcomes of antibiotic therapy. Results: A total of 9121 newly diagnosed children were treated for malignancy and 1697 pediatric patients underwent hematopoietic cell transplantation. K. pneumoniae infections were diagnosed in 527 patients. Their overall incidence was 4.86% in pediatric hematology and oncology patients and 4.95% in patients who underwent hematopoietic cell transplantation. The incidence of infection was higher in patients with acute leukemia than with solid tumors (7.8% vs. 4.1%; OR = 2.0; 95% CI = 1.6-2.4; p < 0.0001). The most frequent source of infection was in the urinary tract at 55.2%. More than 57% of K. pneumoniae strains were extended-spectrum ß-lactamase-positive and almost 34% were multidrug-resistant. Infections with K. pneumoniae contributed to death in 3.22% of patients. Conclusions: K. pneumoniae is one of the most critical pathogens in children suffering from malignancies or undergoing hematopoietic cell transplantation. The incidence of multidrug-resistant K. pneumoniae strains is increasing and contributing to poor clinical outcome.

Bacteria and Candida yeasts in inflammations of the oral mucosa in children with secondary immunodeficiency.

BACKGROUND: Oral microbial flora and a damaged oral mucosa may increase the risk of bacteriemia, fungemia and complications in immunocompromised patients. AIM OF THE STUDY: Assessment of presence: bacteria and Candida spp. in different oral lesions, and the incidence of bacteremia in the case of a damaged mucosa in transplant recipients and patients receiving anti-tumour chemotherapy. MATERIAL AND METHOD: Forty-five patients ­ 18 months to 18 years of life, were included (20 ­ organ recipients, 14­ anti-tumour chemotherapy, 11 ­ control group). Clinical, oral mucosa examination focused on the type, severity and site of lesions, and microbiology assessed the presence of bacteria and fungi in the material from lesions. Blood cultures were performed in ten immunocompromised patients with manifestations of systemic infection. The control material consisted of blood cultures made prior to the onset of oral lesions and after 4­6 weeks following their remission in a diagnosed bacteremia. The statistical analysis was performed. RESULTS: In the subjects with secondary immunodeficiency, among other coagulase-negative Staphylococcus (CoNS), Candidia spp. were more frequent. In cancer patients, mucositis was associated with Candida spp., Streptococcus spp. Organ recipients with stomatitis exhibited the presence of CoNS, Streptococcus viridians and other. Oral lesions in the control group contained Haemophilus parainfluenzae, Neisseria spp. and Staphylococcus aureus. In 30% of immunocompromised patients, oral lesions were accompanied by bacteremia. CONCLUSIONS: A correlation has been found between oral lesions and the presence of S. aureus in patients without secondary immunodeficiency, and of CoNS, Enterococcus spp., Candida spp. in immunocompromised patients.

Infections With Stenotrophomonas maltophilia in Children Undergoing Anticancer Therapy or Hematopoietic Cell Transplantation: A Multicenter Nationwide Study.

BACKGROUND: Infections caused by Stenotrophomonas maltophilia (SM) have documented high mortality rate in immunocompromised patients. AIM: This nationwide multicenter study was performed to analyze the epidemiology of SM infections in children undergoing anticancer therapy (pediatric hematology and oncology [PHO]) or hematopoietic cell transplantation (HCT) over 2012-2019, including incidence and outcome of SM infections, as well as treatment regimens and multidrug resistance. METHODS: Cumulative incidence of SM infections was calculated using the competing risk analysis from the day of diagnosis (PHO setting) or from the day of transplantation (HCT setting). The Kaplan-Meier method was used to determine survival from infection. RESULTS: During the study period of 8 years, a total number of 1356 HCTs and 7337 children newly diagnosed for malignancy were analyzed. Diagnosis of acute leukemia was a predisposing factor for SM infection. The cumulative incidence of SM infections was comparable in HCT patients in comparison to PHO (0.81% vs. 0.76%). High rate of trimethoprim/sulfamethoxazole susceptibility among SM isolates was observed in both groups of patients (80.8%). Although this was the drug of choice, survival rates from SM infections were significantly lower in HCT than in PHO (45% vs. 85%, P = 0.001, log-rank test). We found the transplant procedure and lack of clinical resolution after 18 days of antibiotic therapy to be independent mortality risk factors. CONCLUSIONS: The risk of SM infections and the occurrence of resistant bacterial strains in allo-HCT patients were comparable to PHO patients. Irrespective of target antibiotic therapy, the outcome of SM infections was better in the PHO setting.

Level of Knowledge of Medical Staff on the Basis of the Survey in Terms of Risk Management, Associated with Clostridioides difficile Infections.

Infections caused by the toxigenic strains of Clostridioides difficile in the hospital environment pose a serious public health problem. The progressive increase in hospital infections in Poland indicates that risk management is a tool that is not used in an effective way and significantly differs from the goals set by the Leading Authorities, the Ministry of Health and its subordinate units. Systematic education of medical personnel constitutes the basic element of rational risk management aimed at reducing the number of infections as it allows for the transfer of knowledge, development of appropriate organizational procedures, and improves internal communication. This paper presents the results of a survey conducted in hospital facilities throughout Poland. The study dealt with what medical personnel know about channels of transmission and prevention of Clostridioides difficile infections in the hospital setting, professional training and risk management in terms of reducing the number of infections. The survey reveals that Clostridioides difficile continues to be a serious problem in the inpatient care system. Procedures and management strategies implemented by hospitals in order to limit the spread of the pathogen are predominantly focused on short-term action, which does not lead to a real improvement in terms of hospitalized patients' safety. The infection risk management system was assessed at a fairly low level. The obtained research results confirmed the research hypotheses that had been formulated.

Prevalence, Epidemiology, Etiology, and Sensitivity of Invasive Bacterial Infections in Pediatric Patients Undergoing Oncological Treatment: A Multicenter Nationwide Study.

Background: Infectious complications (IC) caused by bacterial strains often impede anticancer therapy. The study aimed to retrospectively analyze bacterial IC that could help predict the risk and optimize the empirical treatment for bacterial infections in pediatric cancer patients. Patients and Methods: Over a 72-month period, all-in 5,599 children with cancer: 2,441 patients with hematological malignancy (HM including acute leukemias, Hodgkin and non-Hodgkin lymphomas [NHLs], and Langerhans cell histiocytosis) and 3,158 with solid tumors (STs including central nervous system tumors, neuroblastoma, Wilms' tumor, soft tissue sarcoma, germ cell tumors, Ewing sarcoma, osteosarcoma, hepatoblastoma, and others) were enrolled into the study. Episodes of bacterial infectious complications (EBICs) confirmed by microbiological findings were reported by each hospital and analyzed centrally. Results: At least 1 EBIC was diagnosed in 2,155 (36.8%) children (1,281 [59.4%] with HM and 874 [40.6%] with ST; p < 0.001). All-in 4,860 EBICs were diagnosed including 62.2% episodes in children with HM and 37.8% in children with ST (p < 0.001). Having analyzed the source of infections, blood stream infections predominated, apart from NHL patients in whom the most common type was gut infections. The profile of bacteria strains was different in HM and ST groups (p < 0.001). However, in both groups the most common Gram-negative pathogen was Enterobacteriaceae, with the rate being higher in the HM group. Among Gram-negative strains low susceptibility to ceftazidime, whereas among Enterococcus spp. low susceptibility to vancomycin was noticed. The rate of multidrug-resistant (MDR) pathogens was high, especially for Gram negatives (47.7% vs. 23.9%; p < 0.001). The survival after infections was comparable for HM and ST patients (p = 0.215). Conclusions: The risk of bacterial IC in HM patients was higher than in the ST group. The high rate of MDR strains was detected in pediatric cancer patients, especially in those with HM.

[Evaluation of biofilm formation by Staphylococcus aureus isolated from sputum of cystic fibrosis patients]. / Ocena tworzenia biofilmu przez szczepy Staphylococcus aureus wyizolowane z plwociny pacjentów z mukowiscydoza.

The purpose of this study was to evaluate two screening methods for detection of biofilm formation by eighty clinical Staphylococcus aureus isolates from patients with cystic fibrosis, and evaluation of biofilm production on the polystyrene 96-well tissue culture plates, depending on media applied. All clinical strains were incubated in three different media: Luria-Bertani broth (LB), tryptic soy broth supplemented with 2% glucose (TSBglu) and brain heart infusion (BHI). Biofilm production was screened by staining with crystal violet (CV) or with 2,3,5-triphenyltetrazolium chloride (TTC). Both CV and TTC assays showed, that all analyzed isolates created biofilm, in all tested media, however with different intensity. In conclusion, the CV method was found to be more sensitive than the TTC method, when we need information about whole mass of biofilm. The most optimal medium for the biofilm culture was LB medium.

Draft genome sequence of an Escherichia coli ST410 isolate co-harbouring blaCTX-M-15, blaCMY-42, blaOXA-1, aac(3)-IIa and aac(6')-Ib-cr genes with gyrA and parC mutations isolated from a paediatric patient in Poland.

OBJECTIVES: Escherichia coli is one of the major causative agents of nosocomial infections. Here we report the first draft genome sequence of an E. coli strain (no. 158) isolated in Poland carrying blaCTX-M-15, blaCMY-42, blaOXA-1, aac(3)-IIa and aac(6')-Ib-cr genes together with mutations in the gyrA and parC genes. METHODS: Total DNA was sequenced using an Illumina NextSeq 500 platform. The draft genome of E. coli strain 158 was assembled using SPAdes 3.9 assembler. Contigs were annotated using the Prokka v.1.12 algorithm. Species confirmation, multilocus sequence typing (MLST), serotyping, molecular virulence and resistance traits, and plasmid replicons were analysed using appropriate bioinformatics tools available at the Centre for Genomic Epidemiology website. Additional in silico analyses were also conducted. RESULT: The genome size was estimated at 4883487bp, with 4601 predicted coding sequences. The presence of blaCTX-M-15, blaCMY-42, blaOXA-1, aac(3)-IIa and aac(6')-Ib-cr genes was detected in addition to other antimicrobial resistance genes as well as mutations in the gyrA (Ser83Leu and Asp87Asn) and parC (Ser80Ile) genes. The investigated strain E. coli 158 belongs to ST410. CONCLUSION: To our knowledge, this is the first draft genome of an E. coli strain co-harbouring blaCTX-M-15, blaCMY-42, blaOXA-1, aac(3)-IIa and aac(6')-Ib-cr genes with mutations in gyrA and parC reported in Poland. The reported genome sequence contains valuable information on genetic features of antimicrobial resistance mechanisms of E. coli in Poland.

Infectious complications in children with malignant bone tumors: a multicenter nationwide study.

Objectives: The analysis of epidemiology, risk factors and outcome of infections in children with malignant bone tumors (MBT) undergoing chemotherapy. Methods: In this retrospective nationwide multicenter cross-sectional study, a total number of 126 children with MBT including 70 with Ewing sarcoma (ES) and 56 with osteosarcoma (OSA) were screened for infections over a period of 72 consecutive months. Results: The risk of infection was 7.15-fold higher in patients with ES as compared to the OSA group, especially concerning bacterial infections (4.1-fold increase risk). Bacterial infections occurred in 74.3% patients with ES and in 41.1% with OSA. The median time from diagnosis to first infection was 4.9 months. 33.0% of bacterial episodes were diagnosed as bloodstream (BSI), 31.1% as gastrointestinal tract, 30.1% as urinary tract infection. Infection-related mortality (IRM) from bacterial infection was 6% and 15% in ES and OSA patients, respectively. Cumulative incidence was 7.1% for invasive fungal disease and 6.3% for viral infections. The only significant risk factor for IRM was time to infection ≥5 months since the beginning of chemotherapy. All patients who have died from infection had BSI and were in neutropenia. Conclusions: Infections in the children with MBT in our study occurred with high frequency, especially in patients with ES. The most frequent were bacterial infections, while fungal and viral infections were episodic. Among the bacterial infections, bloodstream, urinary tract and gastrointestinal tract infections occurred with similar frequency. All deceased patients died due to BSI. Bacterial infection occurring ≥5 months since the beginning of chemotherapy was a risk factor for death.

Infectious complications in children treated for hodgkin and non-hodgkin lymphomas in polish pediatric leukemia/lymphoma study group: incidence, epidemiology and etiology.

The objective of this nation-wide study was to evaluate the epidemiology and profile of bacterial (BI), viral (VI), and invasive fungal disease (IFD) in patients treated for non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) between the years 2013-2015. In the analyzed period of time, within the studied group of 328 children diagnosed and treated for lymphomas, at least one infectious complication (IC) was diagnosed i.e. 39.3% children. In these patients there were 350 episodes of IC, therein 80.6% episodes of BI, 11.1% episodes of VI, and 8.3% episodes of IFD. In both groups, NHL and HL patients, a stable level of bacterial infections, with an increase in resistance rates, and increased levels of viral and fungal infections were observed. Profile of BI does not depend on lymphoma type, with predominance of Gram-negative bacteria and higher prevalence of MDR pathogens. The overall survival of lymphoma patients with IC was comparable for different types of infections.

Infections in children with acute myeloid leukemia: increased mortality in relapsed/refractory patients.

The aim of this nationwide study was to describe the epidemiology and profile of bacterial infections (BI), invasive fungal disease (IFD) and viral infections (VI) in patients with de novo and relapsed/refractory (rel/ref) acute myeloid leukemia (AML). Within the studied group of 250 children with primary AML, at least one infectious complication (IC) was diagnosed in 76.0% (n = 190) children including 85.1% (n = 504) episodes of BI, 8.3% (n = 49) - IFD and 6.6% (n = 39) - VI. Among 61 patients with rel/ref AML, at least one IC was found in 67.2% (n = 41) of children including 78.8% (n = 78) of BI, 14.1% (n = 14) of IFD and 7.1% (n = 7) of VI. In all AML patients, within BI Gram-negative strains were predominant. Half of these strains were multi-drug resistant. Characteristics of IFD and VI were comparable for de novo and rel/ref AML. The infection-related mortality was significantly higher, while survival from infection was significantly lower in patients with rel/ref disease.

[The analyze of capability of biofilm synthesis by Staphylococcus aureus strains isolated from children with cystic fibrosis]. / Ocena wytwarzania biofilmu przez szczepy Staphylococcus a ureus izolowane od dzieci chorych na mukowiscydoze.

The aim of this study was to analyse the capability of biofilm synthesis by S. aureus isolates obtained from the respiratory tract of CF (cystic fibrosis) patients. A total of 297 S. aureus strains isolated from 33 CF patients, and 40 isolates obtained from healthy control children, were analysed. Extracellular slime production was determined using phenotypical methods (Congo red agar, and crystal violet) and molecular techniques (icaA and icaD genes amplification). All S. aureus strains possessed the icaA and icaD genes belonging to the operon responsible for slime synthesis. The isolates obtained from the respiratory tract of CS patients more frequently showed the ability to produce a biofilm than those from healthy individuals.

[The frequency of small colony variants of Staphylococcus aureus strains isolated from children with cystic fibrosis]. / Czestosc wystepowania fenotypów small colony variants wsród szczepów Staphylococcus aureus izolowanych od dzieci chorych na mukowiscydoze.

The aim of this study was to determine the frequency of spontaneous and inducible SCV formation in S. aureus isolates obtained from CF patients. A total of 297 S. aureus strains isolated from 33 CF patients, and 40 isolates obtained from healthy control children, were analysed. S. aureus was cultured on Columbia blood agar, Schaedler agar and Chapman agar under aerophilic and microaerophilic conditions. Subinhibitory gentamicin concentrations (1 mg/L) were used to test S. aureus ability to form SCVs. The study showed that the characteristic feature of S. aureus strains, persistently colonizing the airways of CS patients, was the formation of small colony variants. In the subinhibitory gentamicin concentration, S. aureus strains from CS patients formed SCVs more frequently (55%) than isolates from healthy subjects (20%). SCV formation in CF patients was associated with treatment with inhaled aminoglycosides.

Evidence for tetracycline resistance determinant tet(M) allele replacement in a Streptococcus pneumoniae population of limited geographical origin.

A collection of 185 Streptococcus pneumoniae isolates was tested for their susceptibility to antipneumococcal drugs, with a focus on the distribution of tetracycline resistance determinants tet(M) and tet(O). Resistance patterns were compared with established correlates of multidrug resistance, and tetracycline-resistant isolates were tested for clonality and allelic variation within tet(M). Resistance to tetracyclines, penicillins and macrolides were all strongly related to multidrug resistance. Over one-quarter of the strains were tetracycline resistant, all via the tet(M)-mediated mechanism. Restriction fragment length polymorphism analysis revealed a high degree of allelic variation within tet(M) and gave evidence of a clonal and horizontal spread of selected alleles. A tet(M) variant that emerged with the onset of epidemic multidrug-resistant strains was replacing old alleles in the population.

[The analysis of the isolated microorganisms from the respiratory tract of cystic fibrosis patients treated in Children's Memorial Health Institute 1999-2002]. / Analiza drobnoustrojów izolowanych z dróg oddechowych chorych na mukowiscydoze leczonych w IP-CZD w latach 1999-2002.

The aim of the study was, to analyze the microorganisms cultured from materials from the airways of children with cystic fibrosis treated in the Children's Memorial Health Institute in Warsaw during 1999-2002. A total of 411 samples were tested, obtained from the airways of 58 patients with diagnosed mucoviscidosis. The age of the treated patients was within the range of 1 month and 20 years. The bacteriological tests were taken during routine visits in the Consultation and Pulmonology Clinic, which took place 3-4 times a year. The most often isolated strain was Staphylococcus aureus--48%. 17% of the isolates of Haemophilus influenzae and 13% of Pseudomonas aeruginosa were obtained. Most S. aureus, P. aeruginosa and H. infiuenzae isolates showed high susceptibility to tested antimicrobial agents. About 6% of all S. aureus isolates were resistant to methicillin (MRSA). S. aureus was occurring in all age groups with the same frequency. The rods H. influenzae were cultured more often from children under 10 years, while P. aeruginosa more often from older patients.

[Antibiotic resistance of conjunctival bacterial flora in children]. / Antybiotykoopornosc szczepów bakteryjnych worka spojówkowego u dzieci.

PURPOSE: To evaluate conjunctival bacterial flora in children and its resistance to the most frequently antibiotics used by the ophthalmologists in Poland. MATERIAL AND METHODS: Bacterial conjuntival cultures obtained in 593 children without ocular infections. RESULTS AND CONCLUSIONS: Pathogenic bacterial isolates were identified in 26.3% children. Most frequently isolated were Gram-positive cocci (70.5%). Significant resistance of Gram-positive cocci to aminoglicosides (5% to 65%) was observed. Emerging resistance to fluoroquinolones, especially of coagulase-negative staphylococci (in 21%), was also observed.

Antimicrobial resistance of Streptococcus pneumoniae and Haemophilus influenzae isolated from children with community-acquired respiratory tract infections in Central Poland.

Resistance to commonly used antimicrobial agents among the key respiratory pathogens is increasing worldwide and therefore a rational choice of an empirical treatment requires knowledge of both global and local resistance patterns. The susceptibility of 185 Streptococcus pneumoniae and 169 Haemophilus influenzae isolates collected from January 1999 to May 2002 at the Children's Memorial Health Institute, Warsaw, Poland, from 351 children with community-acquired respiratory tract infections (RTIs) has been determined. Of S. pneumoniae isolates, 84% were susceptible to penicillin, 91% to cefaclor, 95% to cefuroxime, 98% to cefotaxime, 79% to erythromycin, 46% to co-trimoxazole, 82% to clindamycin and 59% to tetracycline. The majority (83%) of erythromycin-resistant isolates tested carried the erm(B) gene, conferring the MLS(B) phenotype. All tetracycline-resistant S. pneumoniae strains analysed were tet(M) positive and tet(O) negative. A total of 24% of H. influenzae isolates were beta-lactamase-positive. H. influenzae susceptibility to amoxicillin/clavulanate, cefaclor, cefuroxime, azithromycin, tetracycline and co-trimoxazole was 100, 89, 94, 96, 96 and 43%, respectively.

[Microbiological analysis of blood culture obtained from children hospitalized at the Gastroenterology, Oncology and Daily Chemotherapy Wards of the Children's Memorial Health Institute in the years 1999-2002]. / Mikrobiologiczna analiza wyników posiewów próbek krwi pobranych od dzieci z Oddzialów: Gastroenterologii, Onkologii oraz Dziennego Chemioterapii Instytutu Pomnika-Centrum Zdrowia Dziecka w latach 1999-2002.

The aim of the study was to examine correlations between the use of different kinds of intravascular catheters and the type of microorganisms isolated from blood cultures. Blood samples obtained from gastroenterology, oncology and daily chemotherapy wards were examined. The samples were taken from catheter and peripheral blood in situations where blood infection was suspected. In positive blood samples Gram-positive bacteria, especially methicillin-resistant coagulase negative staphylococci, were dominant. Enterobacteriaceae (Klebsiella sp., E. coli, Enterobacter sp.) were the most often isolated among Gram-negative bacteria. The share of Staphylococcus aureus, Gram-negative bacilli and fungi was greater in the case of samples taken from catheters. The domination of CNS is frequently connected with catheter colonisation or contamination of samples. Intravascular catheters predispose to Staphylococcus aureus, Gram-negative rods and fungal infections.

Carriage of genes for various extended-spectrum beta-lactamases: a novel resistance strategy of Klebsiella pneumoniae in Poland.

Among 110 randomly sampled strains from a collection of 247 extended-spectrum beta-lactamase (ESBL)-producing clinical isolates of Klebsiella pneumoniae collected from hospitalised children in three paediatric hospitals in Poland, 64 strains (58.2%) with multiple ESBLs were found, including five non-clonal strains (4.5%) harbouring bla genes for ESBLs of three families (CTX-M, SHV and TEM). This is the first report of the emergence of triple ESBL-producing K. pneumoniae in Poland. In addition, K. pneumoniae strains harbouring bla genes for TEM-130 and TEM-132 ESBLs were detected in Poland for the first time. Epidemiological analysis of the multiple ESBL-producing K. pneumoniae isolates by pulsed-field gel electrophoresis (PFGE) revealed a relatively high genetic diversity between isolates producing the same combination of enzymes. Clonally related strains were uncommon.