Vanda Plečko

Helicobacter pylori Eradication Therapy Success Regarding Different Treatment Period Based on Clarithromycin or Metronidazole Triple-Therapy Regimens

Background: The study compares the eradication success of standard first‐line triple therapies of different durations (7, 10, and 14 days).

Infrequent Finding of Metallo-β-Lactamase VIM-2 in Carbapenem-Resistant Pseudomonas aeruginosa Strains from Croatia

ABSTRACT One hundred sixty-nine nonreplicate imipenem-resistant Pseudomonas aeruginosa strains isolated in a large hospital on the coastal region of Croatia were studied. The most active antibiotics were colistin and amikacin. Most of the isolates were multiresistant. The most prevalent serotype was O12, followed by O11. Six strains carried the blaVIM-2 gene located in a novel class 1 integron composed in its variable part of the blaVIM-2-blaoxa-10-ΔqacF-aacA4 genes. Metallo-β-lactamase-producing strains belonged to sequence types ST235 and ST111.

First report of KPC-producing Klebsiella pneumoniae in Croatia

Abstract In February 2011, a 78-year-old male patient was admitted to Clinical Hospital Center Zagreb with subdural haematoma. Klebsiella pneumoniae with reduced susceptibility to carbapenems was isolated. PCR revealed the presence of blaKPC, blaTEM, and blaSHV genes. Sequencing of blaKPC gene identified K. pneumoniae carbapenemase (KPC)-2 beta-lactamase. The strain belonged to ST37 clone by multilocus sequence typing. Infection control efforts limited the spread of KPC-producing clone of K. pneumoniae in our hospital so far. To our knowledge, this is the first report of a KPC-producing K. pneumoniae in Croatia.

The effectiveness of systemic eradication therapy against oral Helicobacter pylori

BACKGROUND Helicobacter pylori infection is associated with numerous gastroduodenal diseases. The oral cavity could be a potential extragastric reservoir for H. pylori, and oral H. pylori might cause gastric reinfection after the eradication therapy. The aim of the study was to evaluate the presence of H. pylori in oral cavity of patients with gastric H. pylori infection and to examine the effectiveness of the eradication therapy against H. pylori in stomach and in the oral cavity. METHODS Fifty-six patients with chronic periodontitis and gastric H. pylori were enrolled in the study. Gastric H. pylori infection was determined using (13) C-urea breath test before and 3 months after eradication therapy. The presence of the oral H. pylori was assessed using polymerase chain reaction before and 3 months after eradication therapy. The 1-week eradication therapy consisted of amoxycilin 1 g, clarithromycin 500 mg, and proton pump inhibitor 20 mg twice a day. RESULTS Of 56 subjects with gastric infection, 23 (41.1%) harbored H. pylori in the oral cavity. Eradication rate in stomach was 78.3%, whereas in the oral cavity, H. pylori was not detected from any sample after the eradication therapy. CONCLUSION Almost half of the patients with gastric H. pylori harbored the bacterium in the oral cavity. After the eradication therapy, H. pylori was not detected in the oral cavity, what suggests high effectiveness of the therapy protocol in the oral cavity, or it is possible that oral H. pylori is of a transient character.

Morganella morganii causing fatal sepsis in a platelet recipient and also isolated from a donor's stool

Summary.  Bacterial contamination of blood products causes significant patient morbidity and mortality. Contaminated platelet transfusion is a frequent cause of bacteraemia and sepsis because of the storage conditions of platelets. A fatal case of Morganella morganii platelet transfusion associated with sepsis is described, along with procedures traced back to the isolation of M. morganii from a donors stool. Molecular typing was performed, and the same M. morganii strain was found in blood and post‐mortem organ cultures of platelet recipient and platelet bag and in the donors stool. The route of contamination is unknown. The contamination could be due to either insufficient venipuncture site disinfection or the donors transient bacteraemia. Patient died 5 days after the transfusion.

Prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus strains isolated in a multicenter study of nursing home residents in Croatia.

BACKGROUND Residents of nursing homes (NHs) are often hospitalized and could present a potential reservoir for methicillin-resistant Staphylococcus aureus (MRSA). The aim of the study was to determine the prevalence for MRSA carriage in residents and staff in Croatian NHs and to characterize MRSA strains using genotyping techniques. METHODS A cross-sectional study was performed among 877 residents and staff of 7 NHs representing 3 major Croatian regions. Nasal swabs from residents and staff and other samples from residents with invasive devices were obtained. Identified isolates were submitted to susceptibility testing and genotyping with SCCmec typing, S aureus protein A (spa) locus typing, and pulsed-field gel electrophoresis (PFGE). RESULTS The overall prevalence of MRSA colonization was 7.1% (95 confidence interval, 5.4%-8.8%), ranging from 0% to 28.8%. Four MRSA isolates were found in NH staff. All MRSA isolates were negative for Panton-Valentine leukocidin-encoding genes. SCCmec type II was found in 32 MRSA strains; SCCmec IV, in 27 strains; SCCmec I, in 3 strains. The predominant spa type was t008, found in 49 strains; PFGE analysis revealed 2 major clonal groups. CONCLUSIONS MRSA strains were found to be colonizing residents and staff of 7 NHs in Croatia. Our study demonstrates the spread of 2 clones within and among Croatian NHs. The data presented here provide an important baseline for future surveillance of MRSA in NH.

Epidemic and endemic spread of Klebsiella pneumoniae producing SHV-5 beta-lactamase in dubrava university hospital, Zagreb, Croatia

Abstract Plasmid-encoded resistance to broad-spectrum cephalosporins and aztreonam is becoming a widespread phenomenon in clinical medicine. These antibiotics are inactivated by an array of different extended-spectrum β-lactamases (ESBLs) which have evolved by point mutations of parental TEM or SHV β-lactamases. In a previous study conducted during 1994-1995, SHV-2, SHV-2a and SHV-5 β-lactamases were found among Klebsiella pneumoniae isolates in Dubrava University Hospital. High prevalence of ESBLs among K. pneumoniae strains in this hospital (20%) required further investigation. In this investigation, β-lactamases from 42 K. pneumoniae strains collected in 1997 and 15 in 2004 from Dubrava University Hospital, were characterized in order to study the evolution of plasmid-encoded resistance to extended-spectrum cephalosporins and aztreonam in that hospital over a prolonged study period. Susceptibility to antibiotics was determined by diskdiffusion and broth microdilution method. β-lactamases were characterized by isoelectric focusing, determination of hydrolysis of β-lactam substrates, polymerase chain reaction and sequencing of blaSHV genes. All K. pneumoniae strains and their Escherichia coli transconjugants produced β-lactamase with an isoelectric point of 8.2. Based on sequencing of blaSHV genes enzymes of all transconjugants were identified as SHV-5 β-lactamase which conferred on the producing isolates high level of ceftazidime and aztreonam resistance. In this study, an outbreak of nosocomial infections caused by SHV-5 producing K. pneumoniae was described in 1997 which evolved to endemic spread of SHV-5 producing K. pneumoniae due to multiple plasmid transfer in the Dubrava University Hospital. The strains from 1997 and 2004 were not clonally related. Hospital hygiene measures should be applied in order to control the spread of epidemic strains through the hospital wards and the consumption of the broad-spectrum cephalosporins needs to be restricted to reduce the selection pressure which enables the proliferation of ESBL producers in hospital.

Antimicrobial Susceptibility and Beta-Lactamase Production of Selected Gram-Negative Bacilli from Two Croatian Hospitals: MYSTIC Study Results

Abstract The Meropenem yearly Susceptibility test information Collection (MYSTIC) programme is a global, longitudinal resistance surveillance network that monitors the activity of meropenem and compares its activity with other broad-spectrum antimicrobial agents. We now report the antimicrobial efficacy of meropenem compared to other broad-spectrum agents within the selective Gram-negative pathogen groups from two Croatian Hospitals investigated between 2002-2007. A total of 1510 Gram-negative pathogens were tested and the minimum-inhibitory concentrations (MICS) were determined by broth microdilution method according to CLSI. There was no resistance to either imipenem or meropenem observed for Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis in both medical centers. High resistance rates of K. pneumoniae to ceftazidime (18%), cefepime (17%) and gentamicin (39%) are raising concern. Acinetobacter baumannii turned out to be the most resistant Gram-negative bacteria with 81% resistant to ceftazidime, 73% to cefepime, 69% to gentamicin and 71% to ciprofloxacin. Almost 20% of Pseudomonas aeruginosa strains were resistant to imipenem, 13% to meropenem, 69% to gentamicin and 38% to ciprofloxacin. The prevalence of extended-spectrum beta-lactamases (ESBLs) in E. coli was 10% and in K. pneumoniae 49%. PCR and sequencing of the amplicons revealed the presence of SHV-5 in nine E. coli strains and additional TEM-1 β-lactamase five strains. Five K. pneumoniae strains were positive for bla SHV-5 gene. Eight ESBL positive Enterobacter spp. Strains were found to produce tem and CTX-M β-lactamases. Plasmid-mediated AmpC β-lactamases were not found among K. pneumoniae, E. coli and Enterobacter spp. Three A. baumannii strains from Zagreb University Center were identified by multiplex PCR as OXA-58 like producers. Six A. baumannii strains from Split University Center were found to possess an ISAba1 insertion sequence upstream of bla OXA-51 gene. According to our results meropenem remains an appropriate antibiotic for the treatment of severe infections caused by Gramnegative bacteria. These data indicate that despite continued use of meropenem, carbapenem resistance is not increasing among species tested, except for A. baumannii, in the two study hospitals and suggest that clinicians can still administer carbapenems as a reliable and effective choice in managing serious nosocomial infections.

Sensitivity and Specificity of Various β-Lactam Antibiotics and Phenotypical Methods for Detection of TEM, SHV and CTX-M Extended-Spectrum β-Lactamases

Abstract The aim of this study was to compare the sensitivity and specificity of six different β-lactam antibiotics using five phenotypical tests for detection of extended spectrum beta-lactamases (ESBLs) based on synergism of β-lactam antibiotics and clavulanate. Experiments were performed on a set of 80 Klebsiella pneumoniae strains and 105 Escherichia coli strains with previously characterized ESBLs (SHV, TEM and CTX-M). ESBLs were detected by five different phenotypical methods: MIC (minimum inhibitory concentration) determination of β-lactam antibiotics with and without clavulanate, double-disk synergy test (DDST), inhibitor-potentiated disk-diffusion test (IPDDT), CLSI-Clinical and Laboratory Standard Institution (former NCCLS) combined- disk-test, and modified MAST-disk-diffusion test (MAST-DD-test). Seven antibiotics were tested as indicators of ESBL production: ceftazidime, cefotaxime, ceftriaxone, aztreonam, ceftibuten, cefpodoxime and cefepime. Ceftazidime and aztreonam were the best indicators for SHV-5, SHV-12 and TEM β-lactamases whereas cefotaxime and ceftriaxone were the most sensitive in detection of SHV-2 and CTX-M β-lactamases in DDST, IPDDT and CLSI test. MIC determination of β-lactam antibiotics with and without clavulanate was the most sensitive method. DDST was the least sensitive test. Double-disk synergy test, which is the most frequently used test for detection of ESBLs in routine laboratories, was the least sensitive independently of the indicator antibiotic. Since MIC determination is a very laborious and time consuming method, we would recommend the NCCLS combined disk test or IPDD test for detection of ESBLs in routine laboratories with 5 mm zone augmentation breakpoint.

Chryseobacterium gleum infection in patient with extreme malnutrition and hepatic lesion – case report

Chrysobacterium gleum is a nonmotile, oxidase positive, non-fermentative unsporulate Gram-negative bacillus, bacteria belonging to the genus Chrysobacterium. Infections caused by Chrysobacterium spp are usually health care associated and the most frequent in immunocompromised patients and neonates. In this report we present a case of a 35-yearold female patient admitted to the hospital for extreme malnutrition and a hepatic lesion. Chrysobacterium gleum was isolated from tracheal aspirate and blood culture. The strain was identified with Microflex MALDI Biotyper (Bruker Daltonik, Fremont, CA). The patient was successfully treated with piperacillin/tazobactam. Empirical therapy is difficult due to intrinsic resistance to most antimicrobials which are usually effective against Gram-negative bacteria.