Colonization and microbiology of the motile enterococci in a patient population

Treatment of Helicobacter Pylori İnfection and the Colonization of the Gastrointestinal System by Resistant Bacteria

BACKGROUND AND AIMS

Helicobacter pylori (H. pylori) infections are widely treated with antibiotic regimens such as "Amoxicillin 1 gr 2 × 1 tablet, Clarithromycin 500 mg 2 × 1 tablet, and Lansoprazole 30 mg 2 × 1 tablet" for 14 days. We conducted a prospective observational study to explore whether this treatment protocol serves as a predisposing factor for the colonization of resistant gastrointestinal microflora, namely vancomycin-resistant enterococci (VRE), extended-spectrum beta-lactamase Enterobacterales (ESBL-E), and carbapenem-resistant Enterobacterales (CRE).

MATERIALS AND METHODS

Pre- and post-treatment stool samples from 75 patients diagnosed with H. pylori, without a prior treatment history, were cultured and evaluated based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria.

RESULTS

Of the 75 evaluated patients, a pronounced surge in ESBL-E positivity was observed. Before initiating antibiotic treatment, 12 patients (16%) had ESBL-E-positive strains in their gastrointestinal tract. Notably, this number surged to 24 patients (32%) after the conclusion of the 14-day treatment regimen. The change was statistically significant, with a P value of less than 0.002, indicating a clear association between treatment for H. pylori and heightened ESBL-E colonization. Notably, VRE and CRE remained undetected in patients throughout the study, suggesting that the treatment regimen may specifically amplify the risk of ESBL-E colonization without affecting VRE and CRE prevalence.

CONCLUSIONS

As the inaugural report from Turkey on this issue, our study suggests that antibiotic regimens for H. pylori eradication contribute to the increased risk of ESBL-positive bacterial colonization in the gastrointestinal tract.

Enterococcus casseliflavus and Enterococcus gallinarum as causative agents of spontaneous bacterial peritonitis

Infection by multidrug resistant bacteria is arousing as a relevant issue among hospitalized subjects and is of particular interest in patients with cirrhosis given the frequent use of broad spectrum antibiotics and their altered immune response. We report the first case report of spontaneous bacterial peritonitis (SBP) caused by Enterococcus casseliflavus and the sixth case of SBP caused by Enterococcus gallinarum.

Regional spread ofvanA- orvanB-positiveEnterococcus gallinarumin hospitals and long-term care facilities in Kyoto prefecture, Japan

Following an outbreak ofvanA-positiveEnterococcus faeciumin 2005 in Kyoto prefecture, regional surveillance of vancomycin-resistant enterococci (VRE) was initiated. This revealedvanA- orvanB-positiveEnterococcus gallinarumin multiple facilities. Eighty-eightvanA-positiveE. gallinarumfaecal carriers from 12 facilities and tenvanB-positiveE. gallinarumfaecal carriers from eight facilities were found. Pulsed-field gel electrophoresis profiles of the first isolate from each facility showed that 11 of the 12vanAisolates and three of the eightvanB-positiveE. gallinarumisolates belonged to a single clone. This study confirms the clonal spread ofvanA- orvanB-positiveE. gallinarumin a region and underlines the importance of surveillance of VRE for the presence of vancomycin resistance determinants.

Enterococcal meningitis caused by Enterococcus casseliflavus. First case report

Background

Enterococcal meningitis is an uncommon disease usually caused by Enterococcus faecalis and Enterococcus faecium and is associated with a high mortality rate. Enterococcus casseliflavus has been implicated in a wide variety of infections in humans, but never in meningitis.

Case presentation

A 77-year-old Italian female presented for evaluation of fever, stupor, diarrhea and vomiting of 3 days duration. There was no history of head injury nor of previous surgical procedures. She had been suffering from rheumatoid arthritis for 30 years, for which she was being treated with steroids and methotrexate. On admission, she was febrile, alert but not oriented to time and place. Her neck was stiff, and she had a positive Kernig's sign. The patient's cerebrospinal fluid was opalescent with a glucose concentration of 14 mg/dl, a protein level of 472 mg/dl, and a white cell count of 200/μL with 95% polymorphonuclear leukocytes and 5% lymphocytes. Gram staining of CSF revealed no organisms, culture yielded E. casseliflavus. The patient was successfully treated with meropenem and ampicillin-sulbactam.

Conclusions

E. casseliflavus can be inserted among the etiologic agents of meningitis. Awareness of infection of central nervous system with Enterococcus species that possess an intrinsic vancomycin resistance should be increased.

First report of VanA Enterococcus gallinarum dissemination within an intensive care unit in Argentina

Enterococcusgallinarum is intrinsically resistant to low levels of vancomycin and has been described as a colonizing microorganism causing bacteraemia and infection among immunosupresed patients. Between August 2000 and February 2001, 15 highly glycopeptide-resistant E. gallinarum isolates, one from blood and the remaining from rectal swabs, were recovered in a general hospital of Buenos Aires Province, Argentina. All isolates were characterized by biochemical assays, and displayed MICs of vancomycin in the range 16-128 mg/l and MICs of teicoplanin in the range 16-32 mg/l. In all cases, PCR analysis yield positive results for both vanC1 and vanA genes. E. gallinarum isolates were classified as two clonal types by SmaI-PFGE: clone A (n = 8) and clone B (n = 7) and both harboured a transferable vanA element.

Prevalence of vancomycin-resistant enterococcus in prenatal screening cultures

Recommendations for the perinatal treatment of women colonized with Streptococcus agalactiae include vancomycin prophylaxis for those with severe penicillin allergies and antibiotic-resistant organisms. Because of potential postpartum infections due to vancomycin-resistant enterococci (VRE) and the possible spread of vancomycin resistance, the prevalence of VRE in prenatal screening cultures was determined.

Enterococcus casseliflavus bacteremia. Case report and literature review

Motile Enterococci are rare causes of enterococcal bacteremia, usually in immunocompromised patients. We describe a case of polymicrobial bacteremia, including Enterococcus casseliflavus, Escherichia coli, and Morganella morganii, in an 80-year old woman, shortly after a liver biopsy performed to exclude cholangiocarcinoma. We further discuss the unique genetic characteristics and the clinical significance of such isolates, such as their intrinsic resistance to vancomycin, and the low virulence exhibited clinically. Further workup on the mechanisms of motile Enterococci resistance to vancomycin could probably yield useful information in achieving new ways of facing resistance attributed to the more usual, and malignant Enterococci.

Clinical features and outcomes of bacteremia caused by Enterococcus casseliflavus and Enterococcus gallinarum: analysis of 56 cases

The clinical significance and virulence potential of Enterococcus casseliflavus/flavescens and Enterococcus gallinarum are still uncertain. We retrospectively analyzed 56 cases of significant bacteremia caused by E. casseliflavus or E. gallinarum. Of these cases, 25 (44.6%) were associated with polymicrobial bacteremia, and 43 (76.8%) were associated with entry via the biliary tract. Resistance to vancomycin was observed in 17 (30.4%) of these 56 patients, and this resistance was significantly associated with E. gallinarum bacteremia (adjusted odds ratio [AOR], 10.56; 95% confidence interval [CI], 2.41-46.27) and bacteremia without biliary tract origin (AOR, 6.74; 95% CI, 1.44-31.67). The crude mortality rate was 13%, and the bacteremia-related mortality rate was 1.9%. In conclusion, bacteremia due to E. casseliflavus and E. gallinarum is commonly associated with biliary tract disease and may be associated with a low risk of mortality.

Detection of intrinsic vancomycin resistant enterococci in animal and human feces

Fecal samples from animal species and humans were analyzed by quantitative culture for enterococci and vancomycin resistant enterococci (VRE). Each host species carried enterococci which exhibited intrinsic intermediate resistance to vancomycin and sensitivity to teicoplanin (Van C phenotype). The carriage rate in humans was 9%. Carriage rates varied among animal species with the highest percentages being found in deer, duck, goose, horse and turkey.

Characterization of yellow-pigmented and motile enterococci isolated from intestines of the garden snail Helix aspersa

AIMS

Enterococci associated with garden snails (Helix aspersa) were studied in order to obtain reliable species identification and characterization.

METHODS AND RESULTS

Twelve yellow-pigmented and motile enterococci, isolated from the intestines of garden snails, were phenotypically close to Enterococcus casseliflavus, but they showed certain unusual biochemical characteristics. tRNA intergenic length polymorphism analysis (tDNA-PCR) divided all strains studied into two groups, in full agreement with biochemical test results. 16S rDNA sequencing, DNA base composition analysis and DNA-DNA hybridization results showed unambiguously that the enterococci studied belonged to the species Ent. casseliflavus. The representative strains of described ecovars were deposited in the Czech Collection of Microorganisms (CCM) as Ent. casseliflavus CCM 4868, 4869, 4870 and 4871.

CONCLUSIONS

Enterococcus casseliflavus associated with garden snails can be subdivided into groups.

SIGNIFICANCE AND IMPACT OF THE STUDY

Enterococcus casseliflavus differs from other enterococcal species in that it is typically associated with plants, soil, water and invertebrate animals. The different groups that can be found in these widely occurring bacteria are possibly source-specific ecovars, as exemplified by the Ent. casseliflavus inhabiting the intestines of snails.

Evaluation of 15 motility media and a direct microscopic method for detection of motility in enterococci

Isolation of motile, vanC enterococci has yet to be a major infection control concern; however, rapid detection still is important. We evaluated 15 motility media from three manufacturers and a 2-h direct microscopic method for accurate detection of 89 enterococcal strains, including 72 vanC enterococcal strains. Resistance genes were confirmed by a multiplex PCR method with the vanC gene detected in all motile enterococci. Motility in the 72 vanC enterococci was detected at 30 degrees C within 72 h in BD Biosciences motility nitrate medium and in Remel motility B medium, motility B medium supplemented with methyl-alpha-D-glucopyranoside (investigational), motility S medium, motility test medium, and motility test medium with tetrazolium indicator. Motility was also observed for all vanC enterococci with the 2-h direct (30 degrees C incubation) microscopic detection method. All Enterococcus faecalis and Enterococcus faecium isolates were observed to be nonmotile in all media and by the direct microscopic method. Since differences between the various motility media tested were observed, the medium used for detection of enterococcal motility must be selected carefully.

Clinical and epidemiological features of Enterococcus casseliflavus/flavescens and Enterococcus gallinarum bacteremia: a report of 20 cases

The clinical significance of intrinsically vancomycin-resistant enterococci is not yet fully established, as these organisms are infrequently recovered from clinical specimens. We report our experience with 20 cases of Enterococcus gallinarum and Enterococcus casseliflavus/flavescens bacteremia in humans from 1992 through 1998. Sixteen cases of bacteremia were caused by E. gallinarum. Underlying conditions were present in 19 (95%) of the patients and included malignancy, receipt of transplant, and Caroli's disease. Polymicrobial bacteremia was present in 9 patients (45%). E. gallinarum and E. casseliflavus/flavescens, although they are infrequently isolated from clinical specimens, may cause serious invasive infections.

Occurrence of the vanA and vanC2/C3 genes in Enterococcus species isolated from poultry sources in Malaysia

Enterococcus species isolated from poultry sources were characterized for their resistance to antibiotics, plasmid content, presence of van genes and their diversity by randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). The results showed that all isolates were multi-resistance to the antibiotics tested. Ampicillin (15/70) followed by chloramphenicol (37/70) were the most active antibiotics tested against the Enterococcus spp. isolates, while the overall resistant rates against the other antibiotics were between 64.3% to 100%. All vancomycin-resistant E. faecalis, E. durans, E. hirae and E. faecium isolates tested by the disk diffusion assay were positive in PCR detection for presence of vanA gene. All E. casseliflavus isolates were positive for vanC2/C3 gene. However, none of the Enterococcus spp. isolates were positive for vanB and vanC1 genes. Plasmids ranging in sizes between 1.1 to ca. 35.8 MDa were detected in 38/70 of the Enterococcus isolates. When the genetic relationship among all isolates of the individual species were tested by RAPD-PCR, genetic differences detected suggested a high genetic polymorphisms of isolates in each individual species. Our results indicates that further epidemiological studies are necessary to elucidate the role of food animals as reservoir of VRE and the public health significance of infections caused by Enterococcus spp.

Evaluation of D-xylose and 1% methyl-alpha-D-glucopyranoside fermentation tests for distinguishing Enterococcus gallinarum from Enterococcus faecium

To determine the validity of the rapid xylose and methyl-alpha-D-glucopyranoside (MDG) fermentation tests in distinguishing Enterococcus gallinarum from Enterococcus faecium, 156 well-characterized clinical isolates of enterococci (55 E. gallinarum, 91 E. faecium, and 10 Enterococcus faecalis isolates) known to be of different clones were examined in a blinded fashion. Species identification was confirmed by PCR of the ddl ligase genes of E. faecium and E. faecalis and the vanC1 gene of E. gallinarum. Xylose tests were performed with D-xylose tablets by using a heavy bacterial suspension and were interpreted after 2 h of incubation. Standard MDG fermentation tests were read after 24 h of incubation. The xylose fermentation test had a sensitivity of 98% (54 of 55) and a specificity of 99% (100 of 101) in distinguishing E. gallinarum from E. faecium and E. faecalis. The standard MDG test had a sensitivity of 100% (55 of 55) and a specificity of 95% (96 of 101) after 24 h. The xylose fermentation test is a simple method, easily incorporated into laboratory protocols, that distinguishes E. gallinarum from E. faecium with high sensitivity and specificity in 2 h. The standard MDG test has high sensitivity and can be useful in ruling out the presence of E. gallinarum but requires overnight incubation.

Intrinsically vancomycin-resistant gram-positive organisms: clinical relevance and implications for infection control

Intrinsic resistance to vancomycin in gram-positive bacteria presumably predates acquired vancomycin resistance in enterococci but it has only recently generated interest. Intrinsically resistant enterococci possessing the vanC gene and the non-enterococcal genera Leuconostoc, Lactobacillus, Pediococcus and Erysipelothrix are known to cause human infection. This review examines the available data on their identification, resistance mechanisms, epidemiology, clinical infections and antimicrobial susceptibility. Intrinsically vancomycin-resistant gram-positives are usually opportunistic pathogens. Although serious infections may occur, treatment options remain available. No additional infection control measures for the intrinsically resistant genera appear justified with currently available evidence, although vigilance should be maintained to detect future changes in susceptibility patterns.