Antimicrobial Stewardship in Pediatrics

Since the discovery of antibiotics in the early 20th century, significant changes have occurred in their usage principles [...].

Postoperative kinetics of pentraxin 3 (PTX3) after congenital heart surgery with cardiopulmonary bypass in pediatric patients

Background

Pentraxins are inflammatory proteins and markers of acute-phase responses. They are divided into short and long subgroups based on the length of the N-terminal region. The most studied short pentraxin is the C-reactive protein (CRP), which is known to be expressed in various inflammatory conditions, including surgical procedures. On the other hand, much less is known about the kinetics of long pentraxin 3 (PTX3) in surgical patients, especially in the pediatric population.

The aim of this prospective study was to determine the early postoperative kinetics of PTX3 in relation to procalcitonin (PCT) and CRP levels in children undergoing congenital heart surgery with cardiopulmonary bypass (CPB).

Methods

A total of 21 children (9 boys and 12 girls, mean age 12 months) were included in the study. Blood samples for determination of CRP, PCT, and PTX3 levels were collected before the surgery and then immediately after its completion (postoperative day 0, POD 0) and subsequently at POD 1, 2, and 3.

Results

Serum PTX3 concentrations increased significantly between POD 0 and POD 1 (mean values were 12.2 and 72.4 ng/ml, respectively, p<0.001), decreased between POD 1 and POD 2 (mean values were 72.4 and 23.6 ng/ml, respectively, p<0.001), and normalized on POD 3 (the mean value was 1.2 ng/ml).

Conclusions

PTX3 concentrations are markedly elevated during the first postoperative day. Under normal circumstances, PTX3 rises and falls quickly, and its second rise in the early postoperative period may be abnormal, however, further studies are necessary.

Cefazolin prophylaxis in children undergoing cardiac surgery with the use of cardiopulmonary bypass-is the dosing correct?

OBJECTIVES

To determine the recommended concentrations of cefazolin to be used for antibiotic prophylaxis during paediatric cardiac surgery with extracorporeal circulation (ECC).

METHODS

Twenty paediatric patients undergoing cardiac surgery with ECC and cefazolin antibiotic prophylaxis were included in the study. Blood samples for measurement of total cefazolin plasma concentration were collected at the following measurement time points: directly after skin incision, 15 min after ECC start, 5 min after ECC cessation and at skin closure. The target concentration was set for ≥40 mg/l, which corresponded to ≥8 mg/l of unbound cefazolin concentration.

RESULTS

The median total cefazolin plasma concentrations at the measurement time points were 62.8, 67.7, 45.8 and 34.2 mg/l, respectively, and target concentrations were achieved in 90%, 85%, 65% and 40% of children, respectively. Among patients who received ≥30 mg of cefazolin per 100 ml of ECC priming, target concentrations after ECC cessation were reached in 80% of patients, while in those with <30 mg cefazolin per 100 ml in 20% of patients (P = 0.031).

CONCLUSIONS

Direct extrapolation of antibiotic prophylaxis recommendations from adults to children may result in suboptimal antibiotic concentrations. An additional cefazolin dose to ECC priming appears necessary and the dosing should be based on ECC priming volume rather than on the weight of the patient.

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.

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.

Correction to: Circulating T Cells of Patients with Nijmegen Breakage Syndrome Show Signs of Senescence

The original version of the article, "Circulating T Cells of Patients with Nijmegen Breakage Syndrome Show Signs of Senescence" incorrectly listed the affiliation of the fourth author, Iwona Solarska. The correct affiliation is "Molecular Biology Laboratory, Institute of Hematology and Transfusion Medicine.

Circulating T Cells of Patients with Nijmegen Breakage Syndrome Show Signs of Senescence

Purpose

The Nijmegen breakage syndrome (NBS) is an inherited genetic disorder characterized by a typical facial appearance, microcephaly, growth retardation, immunodeficiency, and a strong predisposition to malignancies, especially of lymphoid origin. NBS patients have a mutation in the NBN gene which involves the repair of DNA double-strand breaks (DSBs). Here we studied the peripheral T cell compartment of NBS patients with a focus on immunological senescence.

Methods

The absolute numbers and frequencies of the different T cell subsets were determined in NBS patients from young age till adulthood and compared to age-matched healthy individuals (HI). In addition, we determined the expression of senescent T cell markers and the signal joint T cell receptor excision circles (sjTRECs) content.

Results

Our results demonstrate that NBS patients have reduced T cell numbers. NBS patients showed lower numbers of αβ⁺ T cells, but normal γδ⁺ T cell numbers compared to HI. Concerning the αβ⁺ T cells, both CD4⁺ as well as CD8⁺ T cells were excessively reduced in numbers compared to aged-matched HI. In addition, NBS patients showed higher frequencies of the more differentiated T cells expressing the senescent cell marker CD57 and did not express co-stimulatory molecule CD28. These effects were already present in the youngest age group. Furthermore, NBS patients showed lower sjTREC content in their T cells possibly indicative of a lower thymic output.

Conclusions

We conclude that circulating T cells from NBS patients show signs of a senescent phenotype which is already present from young age on and which might explain their T cell immune deficiency.

Electronic supplementary material

The online version of this article (doi:10.1007/s10875-016-0363-5) contains supplementary material, which is available to authorized users.

Genotypic and clinical differences of seropositive Helicobacter pylori children and adults in the Polish population

Helicobacter pylori (H. pylori) plays an important role in the pathogenesis of the upper gastrointestinal tract diseases in both children and adults. The aim of this paper was to assess the differences between the clinical course of the disease in children and adults. This paper also presents an analysis of clinical symptoms, endoscopic and histopathological findings, H. Pylori cagA and vacA genotypes rates and analysis of the sensitivity of these strains to antibiotics in the Polish population, with possible practical and therapeutic implications. The multicenter study on the frequency of H. pylori infections assessed by the presence of antibodies in IgG class against H. pylori in serum was conducted in the years 2002 and 2003. The study group included 6565 children and adults, in 3827 of whom antibodies levels were above 24 U/mL. The authors analyzed clinical and endoscopic symptoms and in some patients with H. pylori seropositivity also histopathological changes, and cagA and vacA genes. Sensitivity of H. pylori strains to antibiotics were also analyzed. Differences between the frequency of infection between children and adults were determined. Endoscopic examination in adults revealed more frequent cases of gastropathy (P=0.003) and erosive gastritis (P=0.001), and in children-thick mucosal folds (P<0.0001). Histopathological examinations carried out in adults have revealed atrophic gastritis and intestinal metaplasia. In children, cagA(+) s1m1 was observed more frequently than in adults (34.0% versus 23.1%; P=0.02) contrary to cagA(-)s2m2 which occurred more frequently in adults (27.1% versus 14.0%; P=0.003). No effect of the infection on nausea, regurgitation, vomiting, heartburn, and abdominal pain in children was detected. However, adults infected with H. pylori suffered from more frequent episodes of heartburn and abdominal pain. The H. pylori strain exhibited a high resistance to metronidazole (higher in adults: 41.7% versus 27.4%; P=0.002), and to clarithromycin (higher in children: 20.2% versus 15.4%; P>0.05), and dual resistance to metronidazole and clarithromycin (higher in children: 9.9% versus 8.4%; P>0.05). Resistance of the H. pylori to amoxicillin and tetracycline was not detected. The conducted study indicated clinical differences in the H. pylori infection in children and adults. Among the differences in children, especially the more frequent infections by the cagA(+)s1m1/m2 strain could have an influence on further consequences of the infection. The obtained results could be useful in therapeutic decisions.

Evaluation of possibilities in identification and susceptibility testing for Candida glabrata clinical isolates with the Integral System Yeast Plus (ISYP)

The aim of this study was to evaluate possibilities of correct identification and susceptibility testing of C. glabrata clinical isolates with Integral System Yeast Plus (ISYP). For species identification, as the reference method, API Candida test and species-specific PCR reactions were used. The potential of antifungal susceptibility testing by the ISYP test was compared with the Sensititre Yeast One. Whilst the reference methods confirmed that the received population (n = 65 isolates) represented only C. glabrata, identification with the ISYP system showed correct data only in the case of 18 strains tested (27.7%). Species identification of the other 47 strains with the ISYP test was not possible at all. Significant differences were also observed for drug susceptibility testing carried out by the ISYP and the Sensititre Yeast One. The highest level of disagreement in classifying strains as resistant or susceptible estimated, as 73.9% and 40.0%, was observed for itraconazole and amphotericin B, respectively. Satisfactory results were only obtained for 5-fluorocytosine with 93.8% agreement between both methods. In our opinion the idea of the ISYP system is certainly good. The combination of identification ability and drug susceptibility testing in one test is very important, especially from a clinical point of view. However, the current version of the ISYP has many disadvantages. We would like to encourage the manufacturer to make an effort and develop a new, more accurate version of the test.

Distribution of HCV genotypes in Poland

Available data on prevalence of HCV genotypes in Poland are insufficient. The aim of the study was the analysis of distribution of HCV genotypes in Poland over the period of recent 10 years regarding the age of patients and the regions of the country.

MATERIAL AND METHODS

Analysis of HCV genotypes in Poland was carried out between 2003 and 2012, and included 14 651 patients from 22 centers where patients with chronic viral hepatitis C are diagnosed and treated. Genotypes were analyzed in age groups (< 20 years of age, 20-40 years of age, > 40 years of age) as well as in populations of HBV and HIV co-infections.

RESULTS

Genotype (G) 1 infection was demonstrated in 79.4%, G2 -0.1%, G3- 13.8%, G4- 4.9%, G6-0.09% and mixed infections in 1.6%. There was no infection with genotype 5. The highest prevalence of G1 was observed in the Łódzkie voivodship (89.2%) and the Slaskie voivodship (86.7%) while the lowest one in the Warmińsko-mazurskie (62.0%) and the Podlaskie voivodships (68.2%). Genotype 3 most commonly occurs in the Warmińsko-mazurskie (28.1%), and the Podlaskie voivodships (23.0%) and is least common in the Małopolskie (7.9%) and the Łódzkie voivodships (9.0%). Genotype 4 is more common in the Kujawsko-pomorskie (11.7%) and the Podlaskie voivodships (8.6%) and relatively less common in the Lubelskie (1.1%) and the Łódzkie voivodships (1.8%). Prevalence of G1 infection in 2003-2004 was 72% and increased up to 85.6% in 2011-2012, that was accompanied by decrease of G3 prevalence from 17% to 8% in this period. In HBV co-infected (n = 83), G1 infection was demonstrated in 85.5%, G3 - in 7.2%, G4 -4.8%, and mixed genotypes in 6%. Among HIV co-infected (n = 391), a much lower prevalence of G1 (33.0%) and a high of G3 (40.4%) as well as G4 (24.0%) were observed.

CONCLUSIONS

There is a geographic variability of HCV genotypes prevalence in Poland. Increase of HCV G1 infections and decrease of G3 and G4 were observed in the last 10 years. Genotypes G3 and G4 occur more often in HCV/HIV co-infected than in HCV mono-infected patients.

Mannan-binding lectin-2 (MBL2) gene polymorphisms in prenatal and perinatal cytomegalovirus infections

Cytomegalovirus (CMV) is the leading cause of congenital infections among neonates. About 10% of newborns with such an infection have clinical symptoms at birth and about 1% of infected fetuses die due to developmental malformations. Mannan-binding lectin (MBL) is considered to be an important factor in innate immunity. Its deficiency is believed to predispose to various (including viral) infections. The aim of this study was to investigate the possible role of MBL2 gene polymorphisms in prenatal and perinatal CMV infections. The frequencies of MBL2 gene exon 1 mutations as well as MBL deficiency-associated variants (LXPA/O+O/O) among newborns with confirmed cytomegalovirus infection were not significantly lower than among non-infected individuals. The distribution of MBL2 haplotypes was similar between the groups studied. These data suggest MBL does not have a major influence on susceptibility to prenatal or perinatal CMV infections.

Genetic similarity of Campylobacter isolates in humans, food, and water sources in central Poland

Campylobacter spp. is an important cause of gastroenteritis in humans throughout the world. However, sources of these infections are often difficult to identify. Therefore, this study aimed at analyzing the genetic relatedness of Campylobacter isolates from environmental and food samples as well as stool specimens of diarrheal patients obtained in a single geographic region in Poland. Only a few Campylobacter jejuni isolates (4/18, 22%) could be assigned to one cluster, whereas the majority were unrelated. In contrast, the majority of Campylobacter coli strains (25/35, 71%) belonged to three pulsed-field gel electrophoresis (PFGE) clusters containing isolates of various origins (i.e., water samples, chicken carcasses, and humans). Isolates belonging to the clusters showed also similar antibiotic resistance patterns and similar genotypes with respect to the occurrence of the virB11 and iam genes. This suggests that Campylobacter strains may circulate between humans, poultry, and recreational water sources in the rural region in central Poland.

Long-term monitoring of Epstein-Barr virus DNA load and humoral parameter abnormalities in pediatric liver transplant recipients before development of malignancy

EBV loads and abnormalities of humoral responses were monitored in 51 pediatric liver transplant recipients as a proposed non-invasive laboratory tool for early detection of changes preceding severe clinical complications. EBV DNA load, concentrations of IgM, IgG, IgA, and monoclonal proteins were determined in each blood sample. EBV DNA was detected in 70.6% of the children, dysgammaglobulinemia of one or more Ig isotype was present in 41.2% of them. MG detected in 43.1% of patients correlated with the presence of EBV DNA (p = 0.003) and was usually preceded by hypergammaglobulinemia. The median maximum EBV load was significantly higher in EBV DNA+/MG+ patients than in EBV DNA+/MG- patients (p = 0.04), although there was no correlation between current viral load and appearance of MG. Four of 15 EBV DNA-negative patients developed MG, preceded by hypergammaglobulinemia in two. Minimization or cessation of immunosuppression in 42 patients, in whom abnormal biomarkers and/or clinical symptoms raised suspicion of disease progression, permitted complete resolution of abnormalities in all but one patient who developed B-NHL and died. Simultaneous monitoring of protein profiles and EBV DNA load together with thorough physical evaluation of children after LTx is important for early implementation of suitable preemptive therapy.

Trends in antimicrobial susceptibility of Campylobacter isolates in Poland (2000-2007)

This study analysed the pattern of antibiotic resistance in 251 Campylobacter strains isolated from symptomatic children hospitalized in 4 large paediatric hospitals in Poland from 2000 through 2007. The highest resistance was found for ciprofloxacin (49.5% for C. jejuni and 51.3% for C. coli), followed by tetracycline (17.5% and 18.0%, respectively), and ampicillin (13.2% and 10.2%, respectively). Almost all isolates were susceptible to macrolides. As much as 22.6% of C. jejuni and 25.6% of C. coli were resistant to more than one class of antimicrobial agents. Multidrug resistance (defined as resistance to at least two classes of antimicrobials) rose significantly from 5.1% in 2000-2003 to 34.6% in 2004-2007.

[Anti-HCV and HCV RNA in patients with the primary Sjögren syndrome]

The subject of study were 104 patients with the primary Sjögren Syndrome (p. Sj. s.) in whom markers of hepatitis C infection were investigated. All the patients fulfilled the criteria of the European Expert Group of the Sjögren Syndrome. Antibodies anti-HCV were found in 20 patients (19.2%) and HCV-RNA found in 5 patients (4.8%). These data were compared with those observed in several European countries and Japan. The following percentages of anti-HCV were observed until now in p.Sj.s. patients: Swedish--2%, Hungarian--6%, Japanese--12%, French--17%, Polish--19% and Spanish--26%. Our patients in whom liver data were available, showed only minor elevations of ALT and AST. International team of experts postulated the delineation of the disease entity: 'HCV-related primary Sjögren syndrome', separate from the p.Sj.s. itself. If this will be substantiated, we can put forward the hypotesis that 'HCV-related p.Sj.s.' may develop in a special subgroup of persons, perhaps genetically predisposed, and is a part of extrahepatic manifestations of HCV infection.

Unique morphological spectrum of lymphomas in Nijmegen breakage syndrome (NBS) patients with high frequency of consecutive lymphoma formation

Nijmegen breakage syndrome (NBS) is an autosomal recessive disorder characterized by microcephaly, immunodeficiency, radiation hypersensitivity, chromosomal instability and increased incidence of malignancies. In Poland 105 NBS cases showing mutations in the NBS gene (nibrin, NBN), have been diagnosed, approximately 53% of which have developed cancer, mainly (>90%) lymphoid malignancies. This study is based upon the largest reported group of NBS-associated lymphomas. The predominant lymphoma types found in these 14 NBS children were diffuse large B cell lymphoma (DLBCL) and T cell lymphoblastic lymphoma (T-LBL/ALL), all showing monoclonal Ig/TCR rearrangements. The spectrum of NBS lymphomas is completely different from sporadic paediatric lymphomas and lymphomas in other immunodeficient patients. Morphological and molecular analysis of consecutive lymphoproliferations in six NBS patients revealed two cases of true secondary lymphoma. Furthermore, 9/13 NBS patients with lymphomas analysed by split-signal FISH showed breaks in the Ig or TCR loci, several of which likely represent chromosome aberrations. The combined data would fit a model in which an NBN gene defect results in a higher frequency of DNA misrejoining during double-strand break (DSB) repair, thereby contributing to an increased likelihood of lymphoma formation in NBS patients.

Comparison of antimicrobial resistance of Campylobacter jejuni and Campylobacter coli isolated from humans and chicken carcasses in Poland

Campylobacter-associated gastroenteritis remains an important cause of morbidity worldwide, and some evidence suggests that poultry is an important source of this foodborne infection in humans. This study was conducted to analyze the prevalence and genetic background of resistance of 149 Campylobacter jejuni and 54 Campylobacter coli strains isolated from broiler chicken carcasses and from stool samples of infected children in Poland from 2003 through 2005. Nearly all isolates were susceptible to macrolides and aminoglycosides. The highest resistance in both human and chicken strains was observed for ciprofloxacin (more than 40%), followed by ampicillin (13 to 21%), and tetracycline (8 to 29%). Resistance to ampicillin and tetracycline rose significantly between 2003 and 2005. Slight differences in resistance between human and chicken isolates indicate that although chicken meat is not the only source of Campylobacter infection in our population, it can be involved in the transmission of drug-resistant Campylobacter strains to humans.

Local presence of cytomegalovirus and Candida species vs oral lesions in liver and kidney transplant recipients

BACKGROUND

Anti-CMV prophylaxis is currently a routine management in patients after organ transplantation. One of the clinical symptoms of CMV infection may be lesions in the oral cavity.The aim of this study was to determine the relationship between CMV infection, occurrence of Candida species and presence of oral mucosal ulceration in transplant recipients.

MATERIAL/METHODS

Twenty fi ve patients after kidney or liver transplantation (mean age 13 years +/-4 years), receiving immunosuppression (tacrolimus, cyclosporine or sirolimus), who presented minor and major recurrent aphtous stomatitis (RAS), atypical ulcerations or focal necrosis in the oral cavity were enrolled into the study. Mean duration of post-transplant follow-up was 4 years and 3 months (+/-3 years and 5 months). Clinical dental examination (Pl I, GI), mycological tests and blood tests for CMV infection (specific IgM antibodies and/or pp65 antygenemia) were performed in all patients. Eighteen specimens of oral mucosa were evaluated for CMV presence in situ.

RESULTS

CMV infection was confirmed in 13 patients with oral mucosal ulceration (46.43%); which were accompanied by gingivitis (average GI=1.34); in two cases Candida albicans was identified. DNA of HCMV was found in-situ in 5.5% of all biopsies, and in 9% of biopsies of patients with clinical CMV infection; changes did not show the presence of Candida spp.

CONCLUSIONS

There is a significant correlation between CMV infection and oral lesions; in some cases, CMV may be a direct cause.

[The analyze of capability of biofilm synthesis by Staphylococcus aureus strains isolated from children with cystic fibrosis]

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.

Diagnosis of Helicobacter pylori infection

A growing interest in non-invasive tests for the detection of Helicobacter pylori has been observed recently, reflecting a large number of studies published this year. New tests have been validated, and the old ones have been used in different clinical situations or for different purposes. Stool antigen tests have been extensively evaluated in pre- and post-treatment settings both in adults and children, and the urea breath test has been studied as a predictor of bacterial load, severity of gastric inflammation, and response to eradication treatment. Several studies have also explored the usefulness of some serologic markers as indicators of the gastric mucosa status. With regard to invasive tests, molecular methods are being used more and more, but the breakthrough this year was the direct in vivo observation of H. pylori during endoscopy.

Helicobacter pylori: microbiology and interactions with gastrointestinal microflora

Helicobacter pylori causes substantial morbidity and mortality, and the course of infection results from complex interactions between host, environmental and bacterial factors. It is generally accepted that H. pylori eradication is the best method of treatment for peptic ulcer disease and prevention of its complications. However, the antimicrobial agents used in eradication regimens cause various alterations in gastrointestinal microflora, which can lead to side effects affecting the patient's compliance. Moreover, antimicrobial therapy is responsible for increasing resistance not only in H. pylori but also in colonising microflora, and, therefore, alternative approaches to the treatment and prevention of H. pylori infection have been investigated.

Hepatitis B virus genotypes in children with chronic hepatitis B in Poland

OBJECTIVES

To analyse the distribution of HBV genotypes in Polish children with chronic hepatitis B, and to assess the relation between the viral genotype and the severity of liver damage.

METHODS

Serum samples from children with chronic hepatitis B were used for biochemical and serological testing, and for determination of HBV genotypes by a nested-multiplex-polymerase chain reaction. Liver biopsies were obtained for histological assessment, which was performed according to the Batts and Ludwig scoring system of chronic hepatitis.

RESULTS

Of 78 children with chronic hepatitis B, 74 had an identifiable HBV genotype: 86.5% were infected with genotype A, and 13.5% were carriers of genotype D. The frequency of HBeAg clearance and the levels of alanine aminotransferase and serum aspartate transaminase were comparable in both genotype groups. There was no correlation between the HBV genotype and either activity of liver inflammation or liver fibrosis.

CONCLUSIONS

This study shows that the distribution of HBV genotypes in Polish children with chronic HBV infection reflects the general prevalence of HBV genotypes in Europe. The course of chronic hepatitis B in children is not significantly influenced by viral genotypes A or D.

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.

Lack of an association between Helicobacter infection and autoimmune hepatitis in children

An association between Helicobacter infection and autoimmune hepatitis (AIH) in children was investigated. The prevalence of antibodies to H. pylori did not differ between the AIH and the control group, (22% versus 14%), and antibodies to non-gastric Helicobacter were not detected in either group. H. pylori DNA was found in two AIH liver tissues, but Helicobacter was not cultured from any sample.

[Preliminary results and complications of HCV treatment after liver transplantation]

The aim of study was to report the preliminary results and complications of HCV infection treatment after liver transplantation.

MATERIAL

Six patients after liver transplantation (one after combine liver and kidney) had been qualified to treatment with pegylated interferon and ribavirin.

RESULTS

In four patients the therapy was discontinued due to severe side effects (anaemia, cholestasis, sepsis, acute rejection). In two patients the normalization of biochemical parameters of liver function was achived after treatment.

CONCLUSION

HCV treatement in solid organ recipients should be individualised.

[Management of children with HBV or HCV infection before and after liver and/or kidney transplantation]

OBJECTIVE

The aim of this article is to present current guidelines for the management of children with hepatitis B or C before and after liver and/or renal transplantation.

METHODS

Analysis of: (1) recommendations on treatment of hepatitis B and C issued by Polish Expert Groups, and (2) National Health Fund treatment programs for 2005 and 2006.

RESULTS

Specific guidelines for treatment of children with HBV or HCV infections qualified for liver and/or kidney transplantation are discussed.

CONCLUSIONS

National Health Fund treatment programs for 2005 and 2006 do not allow to treat transplant children according to the recommendations.

Antimicrobial resistance of in Poland: a multicentre study

The resistance of Helicobacter pylori to antimicrobials, known to be increasing in many countries, is an important factor compromising the efficacy of eradication therapy. Therefore, our study aimed at analysing the current susceptibility status of H. pylori in Poland. A total of 337 H. pylori isolates were cultured from children (N=179) and adults (N=158) from various regions of the country from January 2001 to December 2004. All strains were susceptible to amoxicillin and tetracycline. The overall resistance to clarithromycin (CL) was 28%, but there were significant differences between the centres (ranging from 0% to 33%) and between child and adult isolates (28% versus 15%, respectively; P=0.01) for primary a resistance. Altogether, 46% of H. pylori isolates were resistant to metronidazole (MTZ) and 20% of isolates were simultaneously resistant to CL and MTZ.

Prevalence of potential virulence markers in Polish Campylobacter jejuni and Campylobacter coli isolates obtained from hospitalized children and from chicken carcasses

The pathogenicity of thermotolerant Campylobacter species, common food-borne pathogens, depends on certain factors unevenly distributed among strains of different origin. The prevalence of such markers has never been examined in a population of Polish Campylobacter strains of human and poultry origin. Therefore, we analysed the presence of the cadF, cdtA, cdtB and cdtC genes and the iam sequence in Campylobacter jejuni (n = 115) and Campylobacter coli (n = 57) isolates from children with diarrhoea and from chicken carcasses. The cadF gene was present in nearly 100% of Campylobacter isolates tested, regardless of their origin or species. In contrast, the iam region was found in 83.3% and 100% of C. coli isolates from children and chickens, respectively, but in only 1.6% and 54.7%, respectively, of C. jejuni isolates. Similarly, the detection rates of cdt genes varied between human and chicken isolates. All three cdt genes were found in nearly all C. jejuni isolates from both children and chickens, but in only 5.6% of human C. coli isolates as compared to 87.2% of chicken C. coli isolates. This different distribution of genetic markers between human and chicken isolates indicates that some Campylobacter infections in children may have additional sources other than contaminated chicken meat.

Antimicrobial susceptibility of aerobic microorganisms isolated from intraabdominal infections in pediatric patients in Poland

BACKGROUND

Growing resistance to antibiotics among both community-acquired and hospital pathogens is making the treatment of most infections increasingly difficult. Therefore, the aim of our multi-center study was to determine the antimicrobial susceptibility of the most frequent aerobic microorganisms isolated from children with intraabdominal infections.

MATERIAL/METHODS

Bacterial pathogens were isolated from 256 consecutive patients treated in five large specialized hospitals in Poland from January 2001 to February 2002. Minimal inhibitory concentrations (MICs) of piperacillin, piperacillin-tazobactam, cefotaxime, ceftazidime and cefepime were determined by Etests. The production of extended spectrum beta-lactamases (ESBL) was detected by a double-disk test.

RESULTS

Piperacillin-tazobactam was the most active agent against Enterobacteriaceae and Pseudomonas aeruginosa, inhibiting 92% and 78% of isolates respectively. Susceptibility of Enterobacteriaceae to cefotaxime, ceftazidime and cefepime was 73%, 73% and 87% respectively, and susceptibility of P. aeruginosa to both ceftazidime and cefepime was 76%. Extended-spectrum beta-lactamases were detected in 56% Klebsiella sp. and 11.5% E. coli, but the vast majority of these isolates remained susceptible to piperacillin-tazobactam (MIC(90) = 12 mg/L and MIC(90) = 1 mg/L, respectively).

CONCLUSIONS

Piperacillin/tazobactam remains a valuable therapeutic option in Polish pediatric patients with intraabdominal infections, due to its good activity against ESbetaL-producing organisms and P. aeruginosa.

Persistence of HBV-DNA in children with chronic hepatitis B who seroconverted to anti-HBs antibodies after interferon-alpha therapy: correlation with specific IgG subclass responses to HBsAg

BACKGROUND/AIMS

We examined the persistence of HBV-DNA in sera collected 4-10 years after IFN-alpha therapy from patients with chronic hepatitis B who had seroconverted to anti-HBs antibodies. We also wanted to assess whether any association exists between HBV-DNA status and the IgG anti-HBs subclass responses.

METHODS

Sera were obtained from 38 patients and the following parameters were determined in each of them: (1) serological markers of HBV; (2) concentrations of IgM, IgG, IgA; (3) total IgG subclasses. HBV-DNA and IgG anti-HBs subclasses were determined in anti-HBs positive sera.

RESULTS

Four to 10 years after therapy, anti-HBs were found in 37 of 38 patients (GMT: 775IU/L). In 13 of them (35.1%) free and/or bound HBV-DNA was present in sera. Significant differences in the profiles of IgG anti-HBs were observed when the HBV-DNA status was considered. Patients with undetectable HBV-DNA responded mainly with IgG1 and/or IgG3, while in the HBV-DNA-positive group, a high contribution of IgG4 was found.

CONCLUSIONS

Our study showed that HBV-DNA may persist for a long time after IFN-alpha therapy despite the appearance of anti-HBs antibodies. The monitoring of specific IgG subclasses may be of predictive value for HBV-DNA persistence.

[Persistence of hepatitis B virus in children after interferon-alpha therapy despite the seroconversion in HBsAg/anti-HBs system]

OBJECTIVE

The aim of our study was to assess: (1) whether seroconversion to IgG anti-HBs, induced by IFN-alpha therapy in children with chronic active hepatitis B, is maintained 4-10 years after treatment; and (2) whether HBV-DNA is present in circulation despite the synthesis of anti-HBs.

METHODS

Serum samples were collected from 38 patients and serological markers of HBV were determined in each of them. HBV-DNA was determined by PCR in anti-HBs positive sera. Serum samples obtained from 19 subjects with a complete spontaneous seroconversion after acute HBV served as controls.

RESULTS

Four to 10 years after therapy, anti-HBs were present in ca. 97.4% patients with GMT value of 775 IU/L vs 127 IU/L found in controls. HBsAg was found in 2/38 subjects. In 13 out of 37 patients (35.1%) free and/or bound HBV-DNA was present.

CONCLUSIONS

This study showed that seroconversion induced by IFN-alpha may not be a sustained phenomenon. HBV-DNA may persist for a long time after therapy despite the anti-HBs synthesis.

IgG subclass response to Helicobacter pylori and CagA antigens in children

Specific serum IgG subclass antibodies against Helicobacter pylori antigens and recombinant CagA were analysed in 75 symptomatic children with histologically confirmed H. pylori infection. H. pylori stimulated an IgG1 predominant response, and IgG3 titres showed a positive association with peptic ulcer disease, chronicity of antral inflammation and density of H. pylori colonization. Two methods used for assessing serum IgG CagA antibody status, i.e. Western blotting and enzyme-linked immunosorbent assay (ELISA), were concordant. CagA stimulated an IgG1 and IgG3 predominant humoral response. Total CagA IgG titres were higher in children with active and more severe chronic antral inflammation. These findings suggest that in children the systemic humoral immune response to H. pylori infection may reflect gastroduodenal pathology.

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.

[Incidence of the virulence markers iam in Campylobacter jejuni and Campylobacter coli strains isolated from poultry carcases]

Previously found DNA sequence (iam), correlated with the invasiveness of Campylobacter strains, became a starting point for present investigation. Main goal of this study was to isolate number of Campylobacter strains from chicken carcasses, to determine their taxonomic position and to establish the presence of iam sequence in their genoms. It was found, that invasion associated marker is present in all Campylobacter coli strains and in majority but not all Campylobacter jejuni. This may confirm the idea that the marker is not only responsible for diarrhea in humans but also may be important in the colonization of chicken guts.

Presence of anti-preS1, anti-preS2, and anti-HBs antibodies in newborns immunized with Bio-Hep-B vaccine

BACKGROUND

An advantage of the third-generation HBV vaccines containing preS1 and preS2 antigens was suggested by their excellent immunogenicity in humans and the rapid onset of antibody response to the S-protein of the vaccine. Sequential studies of the antibody responses to the preS1 and preS2 in relation to the anti-HBs response after immunization with preS-containing vaccines have been made in older children only.

MATERIAL/METHODS

Twenty-eight randomly selected, healthy newborns received either 2.5 microg or 5 microg of Bio-Hep-B (preS1, 2+S) vaccine. The children received 3 doses of vaccine according to a 0, 1, 6 months scheme. Antibodies were determined at months 6 and 9.

RESULTS

The vaccine was well tolerated and safe in newborns. Seroconversion and seroprotection were achieved in 100% of newborns after the second injection. No dose-related effect on the anti-HBs response could be observed; GMTs of anti-HBs antibodies after the 2.5 microg and 5.0 microg doses were 6703 and 7104 Kg IU/l, respectively. The induction of measurable levels of antibodies towards preS1- and/or preS2-antigens with 2.5 microg and 5 microg doses of the vaccine was noted in 29% and 50% of the newborns, respectively, at 6 and/or 9 months of vaccination. An augmented anti-HBs response was elicited in the newborns who produced anti-preS2 after vaccination with 2.5 microg compared with 5.0 microg of the vaccine.

CONCLUSIONS

The vaccine Bio-Hep-B can elicit high titers of anti-HBs antibodies in newborns after only two injections. The response of newborns was directed against preS1 + preS2, or preS2 alone.

Primary resistance of Helicobacter pylori to antimicrobial agents in Polish children

Helicobacter pylori resistance to antimicrobial agents is an important factor compromising the efficacy of treatment. Therefore the aims of our study were: to determine the prevalence of H. pylori resistance to clarithromycin, metronidazole, amoxycillin and tetracycline in children prior to eradication therapy, to compare different methods of susceptibility testing and to detect mutations responsible for clarithromycin resistance. During 1996-2000, 259 H. pylori strains were isolated from antral gastric biopsies. Susceptibility to antimicrobials was determined by the agar dilution method and the Etest. Mutations in the 23S rRNA gene associated with clarithromycin resistance were analysed by PCR-RFLP and direct sequencing. Overall, ninety-six strains (37%) were resistant to metronidazole, 50 strains (19.3%) were resistant to clarithromycin, and 20 strains (7.7%) were simultaneously resistant to both drugs. All cultured isolates were sensitive to amoxycillin and only one isolate (0.4%) was resistant to tetracycline. The agar dilution method and the Etest showed a perfect category correlation for clarithromycin and 4% discrepancies for metronidazole. Primary resistance to clarithromycin was mainly associated with an A2143G mutation in the 23S rRNA gene of H. pylori. The study highlights the high prevalence of H. pylori primary resistance to clarithromycin in Polish children, which implies a need for pretreatment susceptibility testing.

Helicobacter pylori cagA genotype and density of colonization in relation to gastric inflammation in children

OBJECTIVE

To assess the relationship between density determined by quantitative culture, status, and gastric histology in children.

METHODS

Children with clinical symptoms indicating pathology in the upper gastrointestinal tract were referred for endoscopy. From each child blood was taken for serology, and antral biopsies were obtained for quantitative culture of and histology. Histological assessment was performed according to the updated Sydney System. The status of cultured was determined by polymerase chain reaction (PCR) and serum IgG response to CagA by western blotting.

RESULTS

Adequate antral biopsies were obtained from 41 children with positive cultures. CagA IgG antibodies were found in 27 patients (66%), 25 of whom were also positive by the PCR. Two children infected with + strains as determined by the PCR were CagA seronegative. Infection with + strains was associated with significantly higher activity of inflammation and denser bacterial colonization in the antrum compared to negative strains. No correlation was observed between the density of colonization and chronic antral inflammation.

CONCLUSIONS

This study shows that infection of children with + strains of is associated with enhanced activity of antral inflammation and higher density of colonization. There is a good correlation between serum western blot and bacterial PCR positivity in determining status and a positive relationship between histology and quantitative culture in assessing density in paediatric patients.

Primary resistance to clarithromycin in clinical strains of Helicobacter pylori isolated from children in Poland

Helicobacter pylori resistance to clarithromycin is an important factor in the failure of eradication therapy. The resistance results from point mutations in the 23S rRNA gene of H. pylori. The prevalence of primary resistance of H. pylori to clarithromycin in children and mutations associated with resistance were studied and it was found that 23.5% (23/98) of H. pylori strains isolated in our hospital during 1998-2000 were resistant to clarithromycin. The primary resistance was mainly caused by an A2143G mutation, but the isolates with an A2142G mutation had higher MICs for clarithromycin compared with those with an A2143G mutation: median MIC 256 versus 16 mg/l. Comparison of our data with previous results showed that the prevalence of H. pylori resistance to clarithromycin in children has increased in Poland over the last three years, however the difference was not significant (23.5 vs. 17%, P=0.22).