Identification of lactic acid bacteria isolated from human blood cultures

Invasive lactobacillus infection in pediatric patients in a tertiary center in Taiwan - 16 years' experience and literature review

BACKGROUND

Lactobacilli are common microorganisms in the human body. Some species were used as probiotics supplement for many purposes such as preventing necrotizing enterocolitis, or improving allergic diseases or diarrhea. Previously, Lactobacillus infection was thought of as contamination due to its low pathogenicity. However, there have been reports of invasive Lactobacillus infection in immunocompromised patients or patients with comorbidities. The purpose of this study was to analyze the clinical characteristics, antibiotic treatment and outcomes of pediatric patients with invasive Lactobacillus infection.

METHODS

We retrospectively reviewed pediatric patients diagnosed with invasive Lactobacillus infection between 2004 and 2020. Invasive Lactobacillus infection was diagnosed if sterile sites yielded Lactobacillus spp. Clinical manifestations, chronic diseases, potential predisposing factors, medical treatments, antimicrobial susceptibility tests and outcomes were recorded.

RESULTS

Fifteen pediatric patients were diagnosed with invasive Lactobacillus infection, accounting for 2.4% of total invasive Lactobacillus infections during the 16-year period. Eleven infections were bacteremia, two were intra-abdominal infections, and two were biliary tract infections. Fever was the most common symptom. Potential predisposing factors were immunocompromised status, central venous device, prolonged antibiotics use and receiving supplemented probiotics for at least one week. All patients survived with favorable outcomes. Most pathogens were identified as Lactobacillus spp, and two were Lactobacillus rhamnosus, which were related to supplemented probiotics. The antimicrobial susceptibility tests showed that Lactobacilli were all sensitive to ampicillin but resistant to glycopeptides.

CONCLUSION

Invasive Lactobacillus infections in pediatric patients were rare. Despite its low pathogenicity, Lactobacillus could cause invasive infection in those immunocompromised patients.

Identification of novel molecular targets for Weissella species-specific real-time PCR based on pangenome analysis

Some Weissella species are used in probiotic products because of their beneficial effects in humans, whereas some species are considered as opportunistic pathogens that cause infections in humans. Therefore, an accurate and rapid identification of Weissella species is essential to control pathogenic Weissella species or isolate new functional strains with probiotic effects from their habitat. The objective of our study was to extract novel molecular targets using pangenome analysis for the identification of major Weissella species present in food. With 50 genomes representing 11 Weissella species, novel molecular targets were mined based on their 100% presence in the respective strains of the target species and absence in the strains of non-target bacteria. Primers based on molecular targets showed positive results for the corresponding species, whereas 79 non-target strains showed negative results. Standard curves revealed good linearity in the range of 10³-10⁸ colony-forming units per reaction. Our method was successfully applied to 74 Weissella strains isolated from food samples to demonstrate that the molecular targets provided a viable alternative to the 16S rRNA sequence. Furthermore, it was possible to identify and quantify Weissella communities in fermented foods. These results demonstrate that our method can be used for effective and accurate screening for the presence of Weissella species in foods. KEY POINTS: • This is first study to mine novel targets for differentiating 11 Weissella species. • The novel targets showed higher resolution than the 16S rRNA gene sequence. • The PCR method effectively detected Weissella species with opposing properties.

Safety demonstration of a microbial species for use in the food chain: Weissella confusa

Due to their traditional use in food fermentation process for centuries, microbial food cultures are considered to have a safe history of use. A specific microbial risk assessment is therefore rarely conducted for fermented foods and their food cultures, inoculated or naturally present. Some of those food cultures have been also considered for their potential health effect as probiotic strain candidates, for which a specific safety demonstration process has been proposed by a joint expert report of FAO and WHO. The European Food Safety Authority (EFSA) Biohazard panel also provides an approach for evaluating the safety of a strain to be added in the food chain, the Qualified Presumption of Safety (QPS). Weissella confusa, former taxon Lactobacillus confusus, is a food culture characterized in the fermentation process of sourdough. Some strains have been recently proposed for their probiotic potential. The species is also documented in recent infection case reports. It is considered nevertheless to be opportunistic as underlying factors have been suggested to explain the infection. We report here the microbial risk assessment of the species, by studying a collection of 26 food and 17 clinical isolates of Weissella confusa. The phenotypic study, genomic characterization and bibliographical survey will allow us to conclude about the safety of the species and confirm its use for food fermentation and consider specific strains for demonstration of their respective health effects as probiotic candidates.

A case report of polymicrobial bacteremia with Weissella confusa and comparison of previous treatment for successful recovery with a review of the literature

Weissella confusa is a Gram-positive coccus and a commensal bacterium of the human gastrointestinal tract with a potential to cause invasive infections. We report the presence of W. confusa in the blood of a 25-year-old male patient with Crohn’s disease, short bowel syndrome treated with home parenteral nutrition, and a history of recurrent bloodstream infections, admitted to our hospital with fever and malaise. A polymicrobial culture of W. confusa and Aeromonas hydrophila was identified from blood, for which treatment with meropenem and metronidazole was initiated. The literature was searched for previous cases of infection with W. confusa. In total, 14 reports describing infection of 28 patients were found, most cases presenting with bacteremia. The previous reports have described variable susceptibility to antibiotics; however, all were reported to be vancomycin resistant. Because of its similarities to other vancomycin-resistant cocci, isolates of W. confusa might be difficult to identify with traditional methods. Infection may be facilitated by its natural vancomycin resistance, leading to severe infection in hosts with underlying diseases. We describe the treatment of previous cases of infection and suggest treatment methods shown effective in other cases. Vancomycin is often used as treatment of infection with Gram-positive organisms, but this may need to be reevaluated, as several pathogenic bacteria are intrinsically vancomycin resistant. A review on reported treatments of bacteremia by W. confusa suggests the use of daptomycin, amoxicillin-clavulanate or piperacillin/tazobactam as recommendable antibiotic regimens.

Isolation and characterization of high exopolysaccharide-producing Weissella confusa VP30 from young children's feces

Background

Lactic acid bacteria (LAB) are known to have a significant ability to colonize the human intestinal tract and adhere to the surface of intestinal epithelial cells. Among the various lactic acid bacteria, exopolysaccharide (EPS) producing strains are known to provide a variety of health benefits for their hosts (e.g. anti-inflammatory, antioxidant, antitumor and stress tolerant effects). Recently, EPSs and EPS-producing lactic acid cultures have gained interest within the food industry and are playing important roles as biothickeners and texturizing agents due to their hydrocolloidal nature. In this study, 156 lactic acid bacterial strains isolated from fecal samples of healthy young children were screened and evaluated for active EPS-production capability.

Results

Among the various human origin lactic acid flora isolated, Weissella confusa VP30 showed the highest EPS productivity and its EPS producing properties were characterized under various cultural conditions in this research. To document the safety of W. confusa VP30, antibiotic resistance, hemolytic, and ammonia production properties were evaluated in addition. No significant negative results were observed. The maximum EPS production by W. confusa VP30 was 59.99 ± 0.91 g/l after 48 h of cultivation in media containing 10% sucrose, far exceeding EPS production by other bacterial strains reported elsewhere. Based on gel permeation chromatography (GPC), the molecular weight of EPS produced by W. confusa VP30 was 3.8 × 10⁶ Da. Structural analysis of the released EPS fraction by ¹³C and ¹H nuclear magnetic resonance (NMR) spectroscopy revealed that W. confusa VP30 can produce dextran with glucose units linked with 96.5% α (1 → 6) glycosidic bonds and 3.5% α (1 → 3) branches.

Conclusion

The high EPS production capability and safety of W. confusa VP30 justify food industry consideration of this cell strain for further evaluation and potential industrial use.

Literature-based safety assessment of an agriculture- and animal-associated microorganism: Weissella confusa

Although Weissella confusa was established as a species over 25 years ago, it has been understudied until very recently. Several independent observations have driven the recent interest in this important microorganism. First, this Leuconostoc-like species of Lactic Acid Bacteria is associated with agricultural environments, many spontaneous food fermentations-especially carbohydrate-rich vegetable fermentations-and silage. Second, Weissella confusa are members of the autochthonous microbiota of healthy humans and livestock. Third, Weissella confusa-in a strain-specific fashion-are postulated to be good candidates for the development of novel direct-fed microbial products. Fourth, Weissella confusa-in a strain-specific fashion-have been described as opportunistic pathogens-especially in immunocompromised individuals. Last, a distantly related species (Weissella ceti) is the etiologic agent of weissellosis, a disease that affects farmed fish that are important for commercial aquaculture. The purpose of this literature-based safety assessment is to consolidate findings from primary research related to Weissella confusa and its natural associations with and effects on animals, humans, and their agricultural environments. Based on these assessments, it is reasonable to conclude that many Weissella confusa are safe for use in direct-fed microbial products for poultry.

Why Are Weissella spp. Not Used as Commercial Starter Cultures for Food Fermentation?

Among other fermentation processes, lactic acid fermentation is a valuable process which enhances the safety, nutritional and sensory properties of food. The use of starters is recommended compared to spontaneous fermentation, from a safety point of view but also to ensure a better control of product functional and sensory properties. Starters are used for dairy products, sourdough, wine, meat, sauerkraut and homemade foods and beverages from dairy or vegetal origin. Among lactic acid bacteria, Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Pediococcus are the majors genera used as starters whereas Weissella is not. Weissella spp. are frequently isolated from spontaneous fermented foods and participate to the characteristics of the fermented product. They possess a large set of functional and technological properties, which can enhance safety, nutritional and sensory characteristics of food. Particularly, Weissella cibaria and Weissella confusa have been described as high producers of exo-polysaccharides, which exhibit texturizing properties. Numerous bacteriocins have been purified from Weissella hellenica strains and may be used as bio-preservative. Some Weissella strains are able to decarboxylate polymeric phenolic compounds resulting in a better bioavailability. Other Weissella strains showed resistance to low pH and bile salts and were isolated from healthy human feces, suggesting their potential as probiotics. Despite all these features, the use of Weissella spp. as commercial starters remained non-investigated. Potential biogenic amine production, antibiotic resistance pattern or infection hazard partly explains this neglecting. Besides, Weissella spp. are not recognized as GRAS (Generally Recognized As Safe). However, Weissella spp. are potential powerful starters for food fermentation as well as Lactococcus, Leuconostoc or Lactobacillus species.

A therapeutic benefit of daptomycin against glycopeptide-resistant gram-positive cocci bloodstream infections under neutropenia

Antibiotic-resistant infections remain to be a major issue for all over the world. Although appropriate diagnosis and rapid treatment initiation are crucially important particularly in immunocompromised patients, selection of antibiotics without identification of causative bacteria is often challenging. A 44-year-old woman with acute myeloid leukemia (AML) under myelosuppression suffered from teicoplanin-resistant gram-positive cocci bacteremia. Taking severe neutropenia due to chemotherapy and glycopeptide-resistance into account, teicoplanin was empirically substituted with daptomycin, which led to prompt defervescence. This microorganism later turned out to be Leuconostoc lactis (L. Lactis), and daptmycin was continued to use based on antimicrobial susceptibility tests. As a result, empiric use of daptomycin successfully controlled glycopeptide-resistant gram-positive cocci bacteremia under neutropenia. This is the first report of daptomycin treatment for L. lactis bacteremia in a patient with AML under neutropenia. Our findings suggest that daptomycin would be a suitable treatment option for glycopeptide-resistant gram-positive cocci bloodstream infections, especially in myelosuppressive patients.

Lactobacillus bacteremia: Pathogen or prognostic marker?

OBJECTIVE

Lactobacillus bacteremia is a rare event and its epidemiology is poorly known. Whether Lactobacillus bacteremia is a contaminant, a risk factor, or a risk marker of death remains an open question.

PATIENTS AND METHODS

We conducted a retrospective study of patients presenting with Lactobacillus bacteremia (LB), between January 2005 and December 2014, at the Grenoble University Hospital.

RESULTS

LB was observed in 38 patients (0.34% of all positive blood cultures). Cancer (40%), immunosuppression (37%), and use of central venous devices (29%) were frequently associated with LB. We observed a significant increase with time in the number of Lactobacillus positive blood cultures among all blood cultures performed (P=0.04). LBs were divided into two clinical-biological presentations: secondary bacteremia with a known portal of entry (n=30) and isolated bacteremia (n=8). Case fatality was 31% at D28, 55.2% at 1 year in the secondary bacteremia group, and 12.5% (both at D28 and 1 year) in the isolated bacteremia group. Secondary bacteremia with a known portal of entry was significantly associated with case fatality after adjustment for age, co-infection, cancer, immunosuppression, diabetes, and sex (OR 14.9 [1.04-216] P=0.047) for fatality at one year, but not for D28 fatality (P=0.14).

CONCLUSION

Lactobacillus bacteremia may be an important marker of disease severity rather than a pathogen, suggesting comorbidities. It should not be considered a contaminant, but should lead physicians to screen for associated infections and underlying diseases.

Bacteremia due to Leuconostoc pseudomesenteroides in a Patient with Acute Lymphoblastic Leukemia: Case Report and Review of the Literature

Leuconostoc species are vancomycin-resistant Gram-positive cocci. Infections due to Leuconostoc species have been reported in various immunocompromised patients, but little is known about such infection in patients with hematologic malignancies. We report a case of Leuconostoc infection in a 44-year-old woman with acute lymphoblastic leukemia. The patient developed a high fever despite antimicrobial therapy with doripenem after induction chemotherapy. After an isolate from blood cultures was identified as L. pseudomesenteroides, we changed the antibiotics to piperacillin-tazobactam and gentamicin, after which the patient recovered from the infection. Physicians should be aware of Leuconostoc species as causative pathogen if they encounter Gram-positive cocci bacteremia resistant to standard antibiotics such as vancomycin and teicoplanin, especially in patients with hematologic malignancies.

Distinctive Intestinal Lactobacillus Communities in 6-Month-Old Infants From Rural Malawi and Southwestern Finland

OBJECTIVE

Our aim was to compare the composition and diversity of Lactobacillus microbiota in infants living in Malawi and Southwestern Finland.

METHODS

The composition and diversity of the Lactobacillus group was analyzed in the feces of healthy 6-month-old infants living in rural Malawi (n = 44) and Southwestern Finland (n = 31), using the quantitative polymerase chain reaction method and PCR-denaturing gradient gel electrophoresis fingerprinting.

RESULTS

Malawian infants had higher counts of lactobacilli than their Finnish counterparts (7.45 log cells/g vs 6.86 log cells/g, P < 0.001, respectively) and the Lactobacillus community was richer and more diverse in the Malawian infants. Leuconostoc citreum and Weissella confusa were the predominant species in both study groups, but Malawian infants were more often colonized by these species (100% vs 74.2%, P < 0.001; 95.5% vs 41.9%, P < 0.001, respectively). Moreover, Lactobacillus ruminis, Lactobacillus gasseri, Lactobacillus acidophilus, and Lactobacillus mucosae were detected more often in the Malawian infants (59.1% vs 0.0%, P < 0.001; 38.6% vs 9.7%, P = 0.004; 29.5% vs 0.0%, P < 0.001; 22.7% vs 3.2%, P = 0.017, respectively). Lactobacillus casei group species, however, were only detected in the Finnish infants.

CONCLUSIONS

Malawian infants have a more abundant Lactobacillus microbiota with a distinct composition compared with Finnish infants. The environment, including diet and hygiene, may be among the factors influencing these differences.

Identification and significance of Weissella species infections

Weissella spp. are non-spore forming, catalase-negative, gram-positive coccobacilli. They are often misidentified by traditional and commercial phenotypic identification methods as Lactobacillus spp. or Lactobacillus-like organisms. Weissella spp. were previously grouped along with Lactobacillus spp., Leuconostoc spp., and Pediococcus spp. Utilization of more sensitive methods like DNA sequencing or Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) has facilitated identification of Weissella as a unique genus. Nineteen species have been identified to date. W. confusa, W. cibaria, and W. viridescens are the only species isolated from humans. The true prevalence of Weissella spp. continues to be probably underestimated. Weissella spp. strains have been isolated from a wide range of habitats including raw milk, feces, fermented cereals, and vegetables. Weisella is believed to be a rare cause of usually nonfatal infections in humans, and is often considered a contaminant. However, in recent years, Weissella spp. have been implicated in bacteremia, abscesses, prosthetic joint infections, and infective endocarditis. Alterations of the gut flora from surgery or chemotherapy are believed to facilitate translocation of Weissella spp. due to disruption of the mucosal barrier, predisposing the host to infection with this organism. Implications of the isolation of Weissella spp. from blood must be interpreted in context of underlying risk factors. Weissella spp. are inherently resistant to vancomycin. Therefore, early consideraton of the pathogenic role of this bacteria and choice of alternate therapy is important to assure better outcomes.

High efficiency recombineering in lactic acid bacteria

The ability to efficiently generate targeted point mutations in the chromosome without the need for antibiotics, or other means of selection, is a powerful strategy for genome engineering. Although oligonucleotide-mediated recombineering (ssDNA recombineering) has been utilized in Escherichia coli for over a decade, the successful adaptation of ssDNA recombineering to Gram-positive bacteria has not been reported. Here we describe the development and application of ssDNA recombineering in lactic acid bacteria. Mutations were incorporated in the chromosome of Lactobacillus reuteri and Lactococcus lactis without selection at frequencies ranging between 0.4% and 19%. Whole genome sequence analysis showed that ssDNA recombineering is specific and not hypermutagenic. To highlight the utility of ssDNA recombineering we reduced the intrinsic vancomymycin resistance of L. reuteri >100-fold. By creating a single amino acid change in the d-Ala-d-Ala ligase enzyme we reduced the minimum inhibitory concentration for vancomycin from >256 to 1.5 µg/ml, well below the clinically relevant minimum inhibitory concentration. Recombineering thus allows high efficiency mutagenesis in lactobacilli and lactococci, and may be used to further enhance beneficial properties and safety of strains used in medicine and industry. We expect that this work will serve as a blueprint for the adaptation of ssDNA recombineering to other Gram-positive bacteria.

Weissella sp. outbreaks in commercial rainbow trout (Oncorhynchus mykiss) farms in Brazil

The genus Weissella contains 14 bacterial species that usually occur in nutrient-rich environments and in fermented foods and beverages. Outbreaks of hemorrhagic septicemia were reported in three commercial rainbow trout (Oncorhynchus mykiss) farms in Brazil in 2008 and 2009. Seventy-seven Gram-positive isolates were obtained from 41 diseased fish from these farms. The bacterial strains were identified as Weissella at the genus level using biochemical tests, Weissella genus-specific PCR, and 16S rRNA sequencing. To evaluate potential routes of infection, rainbow trout juveniles were experimentally infected with the pathogen. In addition, the resistance of the pathogen to five antibiotics was tested, and provisional epidemiological cut-off values were calculated using the normalized resistance interpretation (NRI). All isolates presented similar phenotypic profiles and positive reactions for Weissella genus-specific PCR. The 16S rRNA sequences of the Brazilian strains showed 100% similarity with sequences of Chinese isolates that previously were identified as the first case of Weissella sp. infection in fish. The disease was successfully reproduced in the laboratory by intraperitoneal injection, immersion, and cohabitation between diseased and healthy fish. All isolates were resistant to sulfonamide, and based on NRI analysis, one, two, and three isolates were classified as non-wild-type (NWT) for erythromycin, oxytetracycline, and norfloxacin, respectively. This is the first description of multiple cases of Weissella sp. infection in rainbow trout farms outside of China, of infectious routes for the disease, and of provisional epidemiological cut-off values for resistance of these bacteria to four antibiotics.

(GTG)(5)-PCR fingerprinting of lactobacilli isolated from cervix of healthy women

A group of lactobacilli isolated from the cervix of 31 healthy women was characterized by (GTG)(5)-polymerase chain reaction (PCR) fingerprinting in order to evaluate this method for identification of vaginal lactobacilli. Obtained fingerprints were compared with profiles available in an in-house database of the CCM bacteria collection covering type and reference strains of multiple lactic acid bacteria including lactobacilli. Selected strains representing individual clusters were further identified by pheS gene sequencing. In total, six lactobacillus species were found among lactobacilli isolated from the cervix of healthy women. The (GTG)(5)-PCR method identified Lactobacillus gasseri (11 strains), Lactobacillus fermentum (one), and some of the Lactobacillus jensenii strains (eight out of 11), but failed to identify the remaining strains, including the Lactobacillus crispatus (18), Lactobacillus mucosae (one), and Lactobacillus vaginalis (one) species. L. jensenii strains were distributed over two fingerprint clusters. The majority of samples was dominated by one (GTG)(5)-PCR type. The rep-PCR fingerprinting using the (GTG)(5) primer allowed straightforward identification of many, but not all, isolates. This method has been shown to be a useful tool for fast screening and grouping of vaginal lactobacilli, but its combination with another identification method is needed to obtain reliable identification results. In addition, Lactobacillus acidophilus was not shown to be the most common inhabitant of the female genital tract as generally assumed.

Weissella confusa bacteremia in a liver transplant patient with hepatic artery thrombosis

A 54-year-old man with a history of nonalcoholic steatohepatitis and hepatocellular carcinoma presented 2 months after an orthotopic liver transplant with fever and abdominal pain. Two weeks earlier, he had an hepatic artery thrombosis and a biliary stricture, for which an hepatic artery stent and a biliary stent were placed. Laboratory workup was significant for leukocyte count of 7800/mcL with 92% segmented neutrophils, hemoglobin 9.4 g/dL, alanine aminotransferase 98 U/L, aspartate aminotransferase 72 U/L, alkaline phosphatase 358 U/L, albumin 2.8 mg/dL, and total bilirubin 1.6 mg/dL. A computed tomography scan of the abdomen and pelvis revealed multiple small fluid collections in the liver consistent with bilomas, and an hepatic angiogram showed complete occlusion of the common hepatic artery. Two sets of blood cultures were positive for an organism initially identified by MicroScan(®) analysis as an α-hemolytic Streptococcus species that was resistant to vancomycin. Further testing confirmed the organism as Weissella confusa 2 days later. W. confusa is a gram-positive coccobacillus that may be misidentified as a Lactobacillus when cultured. It is commonly found in sewage, carrots, sugar cane, fermented foods, and intestinal flora. Although only 4 cases of clinical infection with W. confusa have been described previously, W. confusa has been isolated from the stool of liver transplant patients, and may be an underreported cause of infection owing to improper identification. As it can cause clinical infection in these immunosuppressed hosts, identification of this organism is paramount because it is vancomycin resistant, and incorrect identification could lead to improper antimicrobial selection and ultimately worsened patient morbidity or mortality.

Bacteraemia caused by Weissella confusa at a university hospital in Taiwan, 1997-2007

Human infections caused by Weissella confusa are rarely reported. Ten patients with bacteraemia caused by W. confusa who were treated at a tertiary-care hospital in Taiwan during 1997-2007 were studied. All isolates were initially misidentified as various Lactobacillus and Leuconostoc species by two commercial automated identification methods, and were confirmed to be W. confusa by 16S rRNA sequencing analysis. MICs of these isolates for ten antimicrobial agents were determined by the agar dilution method. The characteristics of these patients included underlying malignancy (n = 4), presence of a central catheter (n = 6), surgery within the previous 3 months (n = 4) and concomitant polymicrobial bacteraemia (n = 5, 50%). Mortality was directly attributed to bacteraemia in two patients. All isolates exhibited high trimethoprim-sulphamethoxazole and ceftazidime MICs (≥ 128 mg/L) and were inhibited by linezolid, daptomycin, ceftobiprole and tigecycline at 4, 0.12, 2 and 0.12 mg/L, respectively. In conclusion, W. confusa should be included in the list of organisms causing bacteraemia in immunocompromised hosts. Novel antibiotics, including daptomycin, moxifloxacin, doripenem and tigecycline, exert good activity against W. confusa.

Comparison of (GTG)5-oligonucleotide and ribosomal intergenic transcribed spacer (ITS)-PCR for molecular typing of Klebsiella isolates

Molecular typing of Klebsiella species has become important for monitoring dissemination of β-lactamase-producers in hospital environments. The present study was designed to evaluate poly-trinucleotide (GTG)(5)- and rDNA intergenic transcribed spacer (ITS)-PCR fingerprint analysis for typing of Klebsiella pneumoniae and Klebsiella oxytoca isolates. Multiple displacement amplified DNA derived from 19 K. pneumoniae (some with an ESBL-phenotype), 35 K. oxytoca isolates, five K. pneumoniae, two K. oxytoca, three Raoultella, and one Enterobacter aerogenes type and reference strains underwent (GTG)(5) and ITS-PCR analysis. Dendrograms were constructed using cosine coefficient and the Neighbour joining method. (GTG)(5) and ITS-PCR analysis revealed that K. pneumoniae and K. oxytoca isolates, reference and type strains formed distinct cluster groups, and tentative subclusters could be established. We conclude that (GTG)(5) and ITS-PCR analysis combined with automated capillary electrophoresis provides promising tools for molecular typing of Klebsiella isolates.

Leuconostoc bacteremia in three patients with malignancies

Leuconostoc is a Gram-positive coccus characterized by its resistance to glycopeptide antibiotics. Generally, this bacterium is susceptible to β-lactam antibiotics; however, here we present a leukemia patient who developed leuconostoc bacteremia during antimicrobial therapy with carbapenem. The appropriate choice of antibiotics at optimal doses enables leuconostoc infection to be overcome, even in compromised hosts. We report 3 cases of leuconostoc bacteremia: the leukemia case which was successfully treated, along with discussions of two other cases with malignancies.