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.

Infections caused by RSV among children and adults during two epidemic seasons

Respiratory Syncytial Virus (RSV) is one of the most common causes of lower respiratory tract infections in young children, immunocompromised patients (children and adults), patients with chronic respiratory diseases and elderly people. Reinfections occur throughout the life, but the severity of disease decreased with subsequent infection. The aim of this study was to analyze the frequency of RSV infections in two selected subpopulations: young children (below 5 y.) and adults with chronic respiratory diseases (25-87 y.). Nasopharyngeal swabs (334) collected from October 2008 to March 2010 were examined. The presence of RSV genome was determined by RT-PCR and the presence of RSV antigen by quick immunochromatographic test. Positive results of RT-PCR were found in 45.2% of all swabs: 48.6% samples in 2008; 41.5% in 2009; 50.8% in 2010. The highest frequency of RSV-positive samples was in fall-winter months, but differences in RSV epidemic seasons were found. In the first season (2008-2009) an increased number of RSV infections was observed from November 2008, but in the second season--from January 2010. Generally, the frequency of RSV-positive RT-PCR among children was 53%, among adults 25%. The highest difference was observed in the first three-month period of 2010. RT-PCR positive samples were found in 68.5% of children and 5.9% of adults. However, the RSV antigen was found in 44.4% of samples collected from adults in this period. Our results indicate that the contribution of RSV infections during epidemic season of respiratory tract infections in Poland was really high among children and adults.

[Evaluation of biofilm formation by Staphylococcus aureus isolated from sputum of cystic fibrosis patients]

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.

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.

Emergence and persistence of integron structures harbouring VIM genes in the Children's Memorial Health Institute, Warsaw, Poland, 1998-2006

OBJECTIVES

The aim was to perform a genetically detailed study of the emergence of metallo-beta-lactamase (MBL) genes in Pseudomonas spp. in the Children's Memorial Health Institute over a 9 year period.

METHODS

Carbapenem-resistant Pseudomonas spp. isolates were collected from 1998 to 2006 and screened for MBL production. MBL-positive isolates were further investigated by a combination of genetic techniques including PCR, genomic location experiments using pulsed-field gel electrophoresis (PFGE) of I-Ceu1, S1 and SpeI digests, and sequencing.

RESULTS

Of the 20 MBL-containing Pseudomonas isolates collected from 1998 to 2006, 16 Pseudomonas aeruginosa isolates contained an identical class 1 integron structure. Two P. aeruginosa isolates contained the bla(VIM-2) gene, and two Pseudomonas putida isolates harboured the bla(VIM-4) gene cassette in different integron structures. PFGE analysis indicated that all bla(VIM-4)-containing P. aeruginosa isolates were closely related, whereas the P. putida isolates were not. All MBL genes in this study were chromosomally encoded, and all isolates harboured only one class 1 integron. The bla(VIM-2) isolates were clonal, and the genetic structure supporting the bla(VIM-2) gene was found in an identical chromosomal position.

CONCLUSIONS

MBL gene emergence in this hospital has paralleled a 6-fold increase in carbapenem usage. We have found an increase in MBL gene diversity, MBL host organisms and MBL genetic support structures in the hospital over the 9 year study period. There is also compelling evidence of the persistence of individual strains in the hospital throughout the study period. This suggests that once MBL genes have emerged in a hospital environment, they are difficult to remove.

[Diagnosis and treatment option strategy for invasive fungal infections in paediatric intensive care]

During the last 20 years rising prevalence of invasive fungal infections, mainly candidiasis or aspergillosis, are observed in paediatric intensive care units. Infections caused by Candida non-albicans species are a particular problem. Results of treatment depend on fast and correct diagnostics, avoidance of risk factors and selected pharmacotherapy. The local epidemiological situation as well as patient factors should be taken into consideration during treatment. Current recommendations for the diagnosis and strategy of choosing treatment options for invasive fungal infections in paediatric intensive care units are presented.

Trends in antimicrobial susceptibility of Gram-negative isolates from a paediatric intensive care unit in Warsaw: results from the MYSTIC programme (1997-2007)

OBJECTIVES

The Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) programme is a longitudinal global surveillance study to monitor in vitro data on microbial susceptibility in centres that prescribe meropenem. This overview provides data on the susceptibility of Gram-negative bacteria (n = 1300) isolated from clinical specimens of children hospitalized in a paediatric intensive care unit (ICU) during 1997-2007.

METHODS

MICs of meropenem and eight other antibiotics were determined using the CLSI agar dilution method.

RESULTS

Meropenem, imipenem and ciprofloxacin were most active (>90% susceptibility) against the tested isolates. A greater proportion of Pseudomonas aeruginosa isolates was susceptible to meropenem compared with imipenem. Antibiotic susceptibility of Enterobacteriaceae and Acinetobacter baumannii showed an increase in 2007. Only susceptibility of P. aeruginosa to ceftazidime and cefepime increased. The incidence of extended-spectrum beta-lactamase (ESBL) producers among Enterobacteriaceae isolates decreased from 37% in 1997 to 21.8% in 2007, and AmpC beta-lactamase producers decreased from 24.6% to 5.7%. Consumption of cephalosporins remained the same and piperacillin/tazobactam increased 3-fold. During 11 years, despite an increase in carbapenem consumption, meropenem and imipenem have retained excellent activity against the majority of isolates studied.

CONCLUSIONS

The comparison of antibiotic susceptibility of Gram-negative isolates in 1997 and 2007 showed a trend of increase, and the number of beta-lactamase-producing isolates among Enterobacteriaceae showed a trend of decrease possibly related to changes in antibiotic policy.

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.

[The frequency of small colony variants of Staphylococcus aureus strains isolated from children with cystic fibrosis]

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.

[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.

[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.

High activity of meropenem against Gram-negative bacteria from a paediatric Intensive Care Unit, 2001–2005

The susceptibility of Gram-negative bacterial strains (n=620) isolated from clinical specimens of children hospitalized in a paediatric Intensive Care Unit between 2001 and 2005 was tested. Meropenem, imipenem and ciprofloxacin were most active (>90% susceptibility) against the tested isolates, with no observed reduction in activity over 5 years. A decrease in prevalence of extended-spectrum beta-lactamase and AmpC beta-lactamase producing Enterobacteriaceae from 56.3 to 34.1% was found.

[Immunological response (IgM) to Legionella pneumophila infection in children]

Most of the publications report cases of Legionella infection among adults. In our studies the level of IgM to Legionella pneumophila sg 1 was determined by ELISA method in serum samples of 144 children with symptoms of respiratory tract infections. Children were from 5 months to 18 years old. The significant level of IgM was found in 41 sera collected from 34 children aged 2 years and above. There were samples collected from 21 girls and 13 boys. The highest percentage of significant level of IgM was found in the age group 4-10 years (31.8%) and 10-14 years (31.7%). Among the youngest children (below 2 years) the equivocal results were found in 6 samples. The significant difference in IgM level was found between the children age groups. There was not found the significant differences in IgM level depending on gender. Obtained results indicated the importance of such kind of studies and necessity of adjusting cut-off values to age groups of children.

Increase of imipenem resistance among Pseudomonas aeruginosa isolates from a Polish paediatric hospital (1993-2002)

Analysis of the in vitro activity of imipenem and 13 other antibiotics against 2485 Pseudomonas aeruginosa isolates obtained from clinical specimens from children hospitalized during 1993-2002 was performed. In 2002, the percentage of P. aeruginosa isolates susceptible to all tested antibiotics, with the exception of imipenem, increased or remained on nearly the same level as in 1993. An increase of resistance to imipenem from 4.3% to 18.3% was observed. The MIC(90) value of imipenem increased from 2mg/L to 16 mg/L. Simultaneously, a four-fold increase of the usage of carbapenems imipenem and meropenem in the hospital was noted. In 2000-2001, a high incidence of imipenem-resistant strains was observed. The imipenem-resistant P. aeruginosa strains of serotype O6 from the general surgery ward and serotype O11 from the intensive care unit were shown to be clonally related by the pulsed-field gel electrophoresis method.

Combined effect of different lactic acid bacteria strains on the mode of cytokines pattern expression in human peripheral blood mononuclear cells

The balance between immunogenic and tolerogenic activities in human immune system strongly depends on microflora-induced pro-and anti-inflammatory activities. Lactic acid bacteria (LAB) are important components of microflora. The interactions of the different strains of LAB and the cells of immune system are largely unknown. To assess if LAB strains composition would have an effect on the cellular responses profile (proliferation, cytokines synthesis) peripheral blood mononuclear cells (PBMC) model system was used. PBMC were induced by three different strains of LAB: Lactobacillus acidophilus, Lactobacillus delbrueckii spp. bulgaricus, Bifidobacterium bifidum. Tested strains were mixed together, in combinations with each other (pairs) or alone. Both, the LAB mixture as well as the pairs and the single LAB strains induced low lymphocyte proliferation (about 10% of ConA-induced response). However, the single LAB strains and their combinations were quite different cytokines inducers. First, L. acidophilus was much stronger IFN-gamma inducer than the LAB mixture, being a few times higher IL-12 stimulator than L. bulgaricus and B. bifidum. Second, L. bulgaricus and B. bifidum suppressed L.acidophilus-induced IFN-gamma synthesis to the level equal to that induced by the LAB mixture, limiting IL-12 production by about 30% and 70%, respectively. Third, the LAB strains were good IL-10 and TNF-alpha inducers, irrespectively of their combinations used. We conclude that LAB strains' pro or anti-inflammatory potentials are at least in part dependent on their composition. Low LAB mixture-induced IL-12 and IFN-gamma production and relatively high IL-10 and TNF-alpha expression may represent cellular activities normally induced in vivo by a combined action of bacterial antigens. Their presence is important to limit pro-inflammatory reactions (via IL-10) and to provide protection against infections (via TNF-alpha).

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.

[Infection in neutropenic cancer patients--etiology, microbiological diagnostics, treatment]

Therapy of malignancies is often complicated by neutropenia, which increases the risk of severe and rapidly progressing infections caused by bacteria and fungi. The etiology of infections in the past few decades has shifted from gram-negative to gram-positive organisms. Nowadays the most important pathogens are: coagulase-negative staphylococci, alpha-haemolyic streptococci, Staphylococcus aureus and among gram-negative bacteria: Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa. Because the progress of infection in this group of patients can be rapid, empirical antibiotic therapy should be administrated at the onset of fever. Before starting therapy specimen for microbiological culture should be taken. There are many approaches to antibiotic empirical therapy but the most frequently used is the combination of broad-spectrum beta-lactams (cefiazidime, ceftpime, piperacillin/tazobactam, carbapenem) plus aminoglycoside or monotherapy using an extended spectrum beta-lactam.

Urinary D-arabinitol/L-arabinitol levels in infants undergoing long-term antibiotic therapy

Long-term antibiotic therapy is one of the main risk factors for mycosis. The urinary D-arabinitol/L-arabinitol (D-/L-ARA) ratio (a biomarker of several Candida species) was determined by gas chromatography with an electron capture detector in samples from 51 infants undergoing long-term antibiotic therapy. Although 47 of these children had higher D-/L-ARA ratios than healthy controls (P<0.0003), their values nonetheless remained within upper-normal limits (D-/L-ARA ratio of <3.6). Four children with suspected invasive candidiasis had above-normal ratios that normalized with fluconazole treatment.

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.

[Assessment of selected tests in diagnostics of Helicobacter pylori infections]

In the diagnostics of Helicobacter pylori infections the invasive and noninvasive methods are applied. In the epidemiological studies the measurement of antibodies of IgG class against H. pylori in the serum or the respiratory test is used. The aim of the study was comparative evaluation of diagnosing of H. pylori infection on the basis of the measurement of antibodies in the serum, HpFL antigens in stool and culture of biopsy specimens from the gastric mucous.

MATERIAL AND METHODS

The study included 380 children aged 1-18 years drawn randomly for epidemiological analysis of H. pylori infection in Lower Silesia in the year 2001. The study was conducted in the year 2002. In all children the concentration of antibodies against H. pylon' of IgG class in the serum using the ELISA method as well as H. pylori antigen (HpFL) in stool were determined. In 66 children out of the whole group the measurements of antibodies using ELISA method and immunoblotting as well as HpFL test were compared to the results of H. pylori culture. Additionally the Hp Cag (+) strains were determined.

RESULTS

The study demonstrated that in 10% of patients with negative results of IgG class antibodies against H. pylori measurement in the serum (below 24 U/ml) the HpFL test in stool was positive. The sensitivity of the test was 58.9%, specificity 90.0%. The correspondence of HpFL test with positive test for the antibodies in the serum was 90% for the antibodies concentration above 500 U/ml. Assuming that a definite test for the H. pylori infection is culture, the most accurate test for detection of the infection turned out to be the determination of the antigen in the stool and immunoblotting. The parallel increase of antibodies titre together with the increase of prevalence of infection with Hp Cag (+) strains was demonstrated.

CONCLUSIONS

The results of HpFL test in stool samples are comparable to the culture, immunoblotting and antibodies concentration in the serum above 100 U/ml.

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.

[Bacteriological screening in controlling the spread of methicillin resistant Staphylococcus aureus]

Screening of MRSA carriers can be performed at the time of admission to a hospital/a ward or during an outbreak. In this second situation not only patients but also medical staff are examined. Because the anterior nares are a major reservoir of MRSA, the nasal swab is the most important screening sample. Specimens are plated directly on selective media containing fixed concentrations of oxacillin or other antimicrobial agents.

[The analysis of the isolated microorganisms from the respiratory tract of cystic fibrosis patients treated in Children's Memorial Health Institute 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.

[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.

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.

[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]

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.

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.

[Drug sensitivity of Helicobacter pylori strains in children and young people from the region of Łódź]

Combined therapy with a proton pump inhibitor and two antibiotics (metronidazole, clarithromycin and amoxicillin or tetracycline) is applied in the treatment of H. pylori infection. The effects of the treatment depend on drug sensitivity of H. pylori. Growing resistance to some of the applied antibiotics has been observed. The aim of the study was to assess drug sensitivity of Helicobacter pylori strains which were isolated from the gastric mucosa of children and young people living in the macroregion of Łódź. The study comprised 45 children aged between 5 and 18 years. Biopsy specimens were put on transport medium, incubated in microaerophilic environment, then identified. Drug sensitivity to metronidazole, clarithromycin, amoxicillin and tetracycline was assessed. We found resistance to metronidazole in 18% (8/45) children, resistance to clarithromycin in 16% (7/45) children and resistance to both antibiotics in 4% (2/45) children. No resistance to amoxicillin or tetracycline was noted.

[Catheter induced septicaemia]

The most serious catheter-related infections, such as septicaemia are associated with the central venous catheters rather than the peripheral catheters. The main sources of microorganisms are the patient's skin and hospital environment. Bacteria can gain access to blood via the external or the internal catheter surfaces. A number of approaches for the prevention of sepsis associated with catheters have been proposed, with limited success. Beside the careful aseptic techniques, the development of antibacterial polymers offers the greatest potential for further reduction of risk of catheter-related sepsis. However, there is evidence suggesting that an appropriate training of staff in the management and care of catheters is fundamental to achieve a reduction in the incidence of catheter-related infections.

[Susceptibility and frequency of selected groups of bacteria isolated in 2001 from patients at the Holy Cross Cancer Center]

The aim of the presented study was the analysis of microbiological data obtained from patients hospitalized in The Holly Cross Cancer Center in Kielce in 2001. The frequency of important nosocomial pathogens in selected specimens and their susceptibility to antibiotics were determined. The strains were identified by using commercial tests (bioMerieux) and their antibiotic susceptibility patterns were performed by disc diffusion technique. The most prevalent bacteria were Gram-negative rods of Enterobacteriaceae family (43%), mainly Escherichia coli. Only 2.7% strains of isolated Escherichia coli isolated from clinical specimens collected from hospitalized patients were beta-lactamase--positive (ESBL+). The second important group of microorganisms were Staphylococci, followed by Enterococcus spp., Pseudomonas aeruginosa and Candida spp. About twenty eight percent of Staphylococcus aureus isolates were resistant to methicillin.

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.

[Use of molecular biology methods for diagnosing fungal infections]

A total of 130 various clinical materials taken from 48 children with suspected systemic fungal infection were used for the study. Clinical samples were tested by use of classical mycological procedures well as by use of molecular technique (PCR assay). The fragments of 125-bp (EO3) and 317 bp (HSP) specific for C. albicans were used for amplification. Fifty seven samples (48%) were positive for Candida albicans and eighty four (68%) by use of PCR. It should be stressed that 4 blood samples, 21 urine samples and 5 other samples were positive by use of molecular technique, only. PCR is sensitive and rapid method for detection and identification of Candida albicans from clinical materials of children with fungal infection. This technique can be applied for monitoring presence of fungal DNA in tested samples during antifungal therapy.

Detection of cytomegalovirus in infant cerebrospinal fluid by conventional PCR, nested PCR and PCR-Digene

The possibility of amplification of human cytomegalovirus (HCMV) DNA in cerebrospinal fluid (CSF) for the diagnosis of HCMV central nervous system (CNS) infection in infants was studied. Single-step PCR, nested PCR and PCR-Digene were used to assay CSF specimens from 37 patients. Criteria for patient inclusion in the study were: 1. clinical manifestations suggesting CMV neuroinfection such as seizures, hypertonia, hypotonia, intracranial calcification, microcephaly, chorioretinitis; 2. any of the following symptoms: anaemia, hepetomegaly, prolonged cholestatic jaundice, or hepatitis, splenomegaly, thrombocytopenia, intrauterine hypotrophy; 3. serologic presentation, and/or positive results for CMV infection obtained by single-step PCR and PCR-Digene in urine and/or blood. PCR-Digene results were positive in 6 CSF samples. Four CSF samples were positive by nested PCR and 1 CSF sample by single step PCR. We found that the double PCR was about ten or more times more sensitive than single PCR and the PCR-Digene was only three times more sensitive than nested-PCR. The results were correlated with serology. Thirty-three out of 37 examined patients were seropositive (ELISA IgG); ELISA IgM gave positive results in 9 patients. In control studies, cells infected with other members of the herpes virus family were negative with these methods, which suggest that amplification combined with primers from the IE and the L-region of CMV is specific. In conclusion, nested-PCR seems to be the best method for early diagnosis of CMV infection in CSF due to an absence of false positive results and its high specificity and sensitivity.

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.

The status of antimicrobial resistance of Helicobacter pylori in eastern Europe

OBJECTIVE

To evaluate the primary, secondary and combined resistance to five antimicrobial agents of 2340 Helicobacter pylori isolates from 19 centers in 10 countries in eastern Europe.

METHODS

Data were available for centers in Bulgaria, Croatia, the Czech Republic, Estonia, Greece, Lithuania, Poland, Russia, Slovenia and Turkey. Susceptibility was tested by agar dilution (seven countries), E test (five countries) and disk diffusion (three countries) methods. Resistance breakpoints (mg/L) were: metronidazole 8, clarithromycin 1, amoxicillin 0.5, tetracycline 4, and ciprofloxacin 1 or 4 in most centers. Primary and post-treatment resistance was assessed in 2003 and 337 isolates respectively. Results for 282 children and 201 adults were compared.

RESULTS

Primary resistance rates since 1998 were: metronidazole 37.9%, clarithromycin 9.5%, amoxicillin 0.9%, tetracycline 1.9%, ciprofloxacin 3.9%, and both metronidazole and clarithromycin 6.1%. Isolates from centers in Slovenia and Lithuania exhibited low resistance rates. Since 1998, amoxicillin resistance has been detected in the southeastern region. From 1996, metronidazole resistance increased significantly from 30.5% to 36.4%, while clarithromycin resistance increased slightly from 8.9% to 10.6%. In centers in Greece, Poland, and Bulgaria, the mean metronidazole resistance was slightly higher in adults than in children (39% versus 31.2%, P > 0.05); this trend was not found for clarithromycin or amoxicillin (P > 0.20). Post-treatment resistance rates exhibited wide variations.

CONCLUSIONS

In eastern Europe, primary H. pylori resistance to metronidazole is considerable, and that to clarithromycin is similar to or slightly higher than that in western Europe. Resistance to amoxicillin, ciprofloxacin and tetracycline was detected in several centers. Primary and post-treatment resistance rates vary greatly between centers.

Susceptibility patterns of Gram-negative bacteria from a Polish intensive care unit, 1997-2000

The susceptibility of Gram-negative bacterial strains (n=400) isolated from clinical specimens of children hospitalized in a Polish intensive care unit (ICU) between 1997 and 2000 was tested. Meropenem, imipenem and ciprofloxacin were most active (>90% susceptibility) against the tested isolates, with no observed reduction in activity over 4 years. Extended-spectrum beta-lactamases and AmpC beta-lactamase producers among Enterobacteriaceae isolates from this ICU continued to be a serious therapeutic problem, although the carbapenems were highly active against these resistance phenotypes. Resistance to aminoglycosides (gentamicin, tobramycin) and ceftazidime was a characteristic of >40% of tested isolates.

[The safety of patients and staff in the operating room]

The risk of postoperative infection is determined by a number of factors including the underlying health of the patient, the type of surgery and the environment in which the procedure take place. The predominant infective organisms are Staphylococci. Coagulase-negative staphylococci are regarded as emerging pathogens, especially in clean surgery. The operating team is the major source of the contaminated bacteria. Bacteria dispersed from the skin is of greater importance than bacteria from the respiratory tract, so masks are not always necessary in the theatre during an operation except by those at the table. Masks that function as protective barriers are another emerging issue. Due to a greater awareness of HIV and other blood-borne viruses, masks are taking on a greater role in protection health care workers from potentially infectious blood and body fluids. Bloodborne infection pose a large risk to healthcare workers. The incidence of occupational HBV infection has decline as a result of vaccine-induced immunity. Future vaccines against HIV and HCV would be a boon to healthcare workers.