Antimicrobial susceptibility testing of Eggerthella lenta blood culture isolates at a university hospital in Belgium from 2004 to 2018.

OBJECTIVES: Eggerthella lenta is a Gram-positive anaerobic bacillus that is an important cause of bloodstream infections. This study aims to test the susceptibility of Eggerthella lenta blood culture isolates to commonly used antibiotics for the empirical treatment of anaerobic infections. METHODS: In total, 49 positive blood cultures for Eggerthella lenta were retrospectively included from patients hospitalised at the Universitair Ziekenhuis Brussel, Belgium, between 2004 and 2018. Identification was done by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) system. Antimicrobial susceptibility testing was performed using the reference agar dilution method according to Clinical and Laboratory Standards Institute (CLSI) guidelines with Brucella agar supplemented with 5 µg/mL hemin, 1 µg/mL vitamin K1 and 5% laked sheep blood. The minimal inhibitory concentrations were interpreted using the EUCAST breakpoints. Clinical characteristics were collected by reviewing the patient's medical records. RESULTS: All isolates were susceptible to amoxicillin-clavulanate, metronidazole and meropenem. Eighty-eight % of them were susceptible to clindamycin and 94% (20% S, 74% I) were susceptible to piperacillin-tazobactam. The mean age of the patients was 64 (±20) and they showed a 30-day mortality of 27%. The source of infection was in 65.3% of the cases abdominal, 20.4% were sacral pressure ulcers and 14.3% were unknown causes. While all isolates were fully susceptible at standard dosing regimen to amoxicillin-clavulanate, most were only susceptible at increased exposure or resistant to piperacillin-tazobactam. CONCLUSIONS: Our results suggest to be careful with the use of piperacillin-tazobactam and clindamycin in the empirical treatment of Eggerthella lenta infections.

Molecular characterization and antibiotic resistance of Acinetobacter baumannii in cerebrospinal fluid and blood.

The increasing prevalence of carbapenem-resistant Acinetobacter baumannii (CRAB) caused nosocomial infections generate significant comorbidity and can cause death among patients. Current treatment options are limited. These infections pose great difficulties for infection control and clinical treatment. To identify the antimicrobial resistance, carbapenemases and genetic relatedness of Acinetobacter baumannii isolates from cerebrospinal fluid (CSF) and blood, a total of 50 nonrepetitive CSF isolates and 44 blood isolates were collected. The resistance phenotypes were determined, and polymerase chain reaction (PCR) was performed to examine the mechanisms of carbapenem resistance. Finally, multilocus sequence typing (MLST) was conducted to determine the genetic relatedness of these isolates. It was observed that 88 of the 94 collected isolates were resistant to imipenem or meropenem. Among them, the blaOXA-23 gene was the most prevalent carbapenemase gene, with an observed detection rate of 91.5% (86/94), followed by the blaOXA-24 gene with a 2.1% detection rate (2/94). Among all carbapenem-resistant Acinetobacter baumannii (CRAB) observations, isolates with the blaOXA-23 gene were resistant to both imipenem and meropenem. Interestingly, isolates positive for the blaOXA-24 gene but negative for the blaOXA-23 gene showed an imipenem-sensitive but meropenem-resistant phenotype. The MLST analysis identified 21 different sequence types (STs), with ST195, ST540 and ST208 most frequently detected (25.5%, 12.8% and 11.7%, respectively). 80 of the 94 isolates (85.1%) were clustered into CC92 which showed a carbapenem resistance phenotype (except AB13). Five novel STs were detected, and most of them belong to CRAB. In conclusion, these findings provide additional observations and epidemiological data of CSF and blood A. baumannii strains, which may improve future infection-control measures and aid in potential clinical treatments in hospitals and other clinical settings.

Sarocladium and Acremonium infections: New faces of an old opportunistic fungus.

The genera Acremonium and Sarocladium comprise a high diversity of morphologically and genetically related fungi generally found in the environment, although a few species, mainly Sarocladium kiliense and Acremonium egyptiacum, can also be involved in many human infections. Clinical management of opportunistic infections caused by these fungi is very complex, since their correct identification is unreliable, and they generally show poor antifungal response. More than 300 clinical cases involving a broad range of Acremonium/Sarocladium infections have so far been published, and with this review we aim to compile and provide a detailed overview of the current knowledge on Acremonium/Sarocladium human infections in terms of presentation, diagnosis, treatments and prognoses. We also aim to summarise and discuss the data currently available on their antifungal susceptibility, emphasising the promising results obtained with voriconazole as well as their impact in terms of animal infections.

Influence of a cell salvage washing system and leukocyte reduction filtration on bacterial contamination of canine whole blood ex vivo.

OBJECTIVE: To determine the ability of cell salvage washing and leukoreduction filtration to remove bacterial contamination from canine whole blood. STUDY DESIGN: Ex vivo nested cohort study. SAMPLE POPULATION: Commercially purchased fresh canine whole blood (n = 33 units). METHODS: Commercially obtained canine whole blood was inoculated with known concentrations of one of three species of bacteria, Escherichia coli (ATCC 25922), Staphylococcus pseudintermedius (quality control strain; Texas A&M University), or Pseudomonas aeruginosa (ATCC 27853). Negative controls were inoculated with sterile saline. The inoculated blood was processed through a cell salvage system and filtered through a series of two leukocyte reduction filters. Samples were aseptically collected at five points during processing (inoculum, prewash, postwash, post-first filtration, and post-second filtration) for bacterial enumeration. RESULTS: Bacterial concentrations were reduced by 85.2%, 91.5%, and 93.9% for E coli, S pseudintermedius, and P aeruginosa, respectively, after washing (P < .0001), and bacterial concentrations were reduced by 99.9%, 100%, and 100%, respectively, after the first filtration (P < .0001). After the second filtration, none of the three species of bacteria could be isolated (100% reduction). No bacterial growth was obtained from negative controls throughout the study. The type of bacteria (P = .29) did not allow prediction of bacterial reduction. CONCLUSION: Cell salvage washing combined with leukoreduction filtration eliminated bacterial contamination of whole dog blood (P < .0001). CLINICAL SIGNIFICANCE: Cell salvage washing and leukoreduction filtration could be applied to intraoperative autotransfusion in clinical animals, especially those treated for trauma or hemorrhage with concurrent bacterial contamination.

Ameliorative effect of Bacillus subtilis, Saccharomyces boulardii, oregano, and calcium montmorillonite on growth, intestinal histology, and blood metabolites on Salmonella-infected broiler chicken.

This study evaluated the effects of Bacillus subtilis, Saccharomyces boulardii, oregano, and calcium montmorillonite on the physical growth, intestinal histomorphology, and blood metabolites in Salmonella-challenged birds during the finisher phase. In this study, a total of 600 chicks (Ross 308) were randomly distributed into the following dietary treatments: basal diet with no treatment; infected with Salmonella; T1, infected + avilamycin; T2, infected + Bacillus subtilis; T3, Saccharomyces boulardii; T4, infected + oregano; T5, infected + calcium montmorillonite. Our results indicated that feed consumption, body weight gain, total body weight, and feed conversion ratio increased significantly (P < 0.01) in T1 and T2. Villus width increased significantly (P < 0.01) in T1 while the total area was significantly (P < 0.01) higher in T1 and T2 among the treatment groups. Blood protein was significantly (P < 0.01) high in T3 and T4; however, the glucose concentration was significantly (P < 0.01) high in T2, T3, and T4. The treatments increased significantly (P< 0.01) in the treatment groups compared to the negative control. Aspirate aminotransferase (AST) was significantly (P < 0.05) low in T3 compared to the positive control. In conclusion, the results indicated that supplementation of Bacillus subtilis and calcium montmorillonite improved the production performance compared to other feed additives in broiler chicks infected with Salmonella during the finisher phase.

Biofilms busters to improve the detection of Borrelia using PCR.

Lyme disease is an affection caused by a spirochete infection called Borrelia Burgdorferi which may harbor a varied and misleading clinical symptomatology. The serology tests commonly used for diagnosis show a wide sensitivity varying from 34% to 70,5%, leaving many infected patients with false negative tests. Alternative techniques such as polymerase chain reaction (PCR) could be helpful but not conclusive enough. Using biofilm busters, such as stevia and serratiopeptidase, could lead to bacterial blood release, thus increasing the spirochete load, making PCR test more sensitive, thus improving the patient's diagnosis and management.

Emergence of dalbavancin non-susceptible, vancomycin-intermediate Staphylococcus aureus (VISA) after treatment of MRSA central line-associated bloodstream infection with a dalbavancin- and vancomycin-containing regimen.

OBJECTIVES: Dalbavancin is a long-acting lipoglycopeptide with activity against gram-positives, including methicillin-resistant Staphylococcus aureus (MRSA). The potential for lipoglycopeptides, with half-lives greater than 1 week, to select for resistance is unknown. Here we explore a case of MRSA central line-associated bloodstream infection in which dalbavancin and vancomycin non-susceptibility emerged in a urine isolate collected after the patient was treated with vancomycin and dalbavancin sequentially. METHODS: Isolates from blood and urine underwent susceptibility testing, and whole genome sequencing (WGS). The blood isolate was subjected to successive passage in vitro in the presence of escalating dalbavancin concentrations and the emergent isolate was subjected to repeat susceptibility testing and WGS. RESULTS: The blood isolate was fully susceptible to vancomycin; however, MICs of the urine isolate to dalbavancin, vancomycin, telavancin, and daptomycin were at least fourfold higher than the blood-derived strain. Both strains were indistinguishable by spa and variable number tandem repeat (VNTR) typing, and WGS revealed only seven variants, indicating clonality. Four variants affected genes, including a 3bp in-frame deletion in yvqF, a gene which has been implicated in glycopeptide resistance. Vancomycin and dalbavancin non-susceptibility emerged in the blood isolate after successive passage in vitro in the presence of dalbavancin, and WGS identified a single non-synonymous variant in yvqF. CONCLUSIONS: This is the first case in which VISA has emerged in the context of a dalbavancin-containing regimen. The selection for cross-resistance to vancomycin in vitro by dalbavancin exposure alone is troubling. Clinicians should be aware of the possibility for emergence of dalbavancin non-susceptibility and glycopeptide cross-resistance arising following therapy.

The Electron Transport Chain Sensitizes Staphylococcus aureus and Enterococcus faecalis to the Oxidative Burst.

Small-colony variants (SCVs) of Staphylococcus aureus typically lack a functional electron transport chain and cannot produce virulence factors such as leukocidins, hemolysins, or the antioxidant staphyloxanthin. Despite this, SCVs are associated with persistent infections of the bloodstream, bones, and prosthetic devices. The survival of SCVs in the host has been ascribed to intracellular residency, biofilm formation, and resistance to antibiotics. However, the ability of SCVs to resist host defenses is largely uncharacterized. To address this, we measured the survival of wild-type and SCV S. aureus in whole human blood, which contains high numbers of neutrophils, the key defense against staphylococcal infection. Despite the loss of leukocidin production and staphyloxanthin biosynthesis, SCVs defective for heme or menaquinone biosynthesis were significantly more resistant to the oxidative burst than wild-type bacteria in human blood or the presence of purified neutrophils. Supplementation of the culture medium of the heme-auxotrophic SCV with heme, but not iron, restored growth, hemolysin and staphyloxanthin production, and sensitivity to the oxidative burst. Since Enterococcus faecalis is a natural heme auxotroph and cause of bloodstream infection, we explored whether restoration of the electron transport chain in this organism also affected survival in blood. Incubation of E. faecalis with heme increased growth and restored catalase activity but resulted in decreased survival in human blood via increased sensitivity to the oxidative burst. Therefore, the lack of functional electron transport chains in SCV S. aureus and wild-type E. faecalis results in reduced growth rate but provides resistance to a key immune defense mechanism.

Within-host spatiotemporal dynamics of systemic Salmonella infection during and after antimicrobial treatment.

OBJECTIVES: We determined the interactions between efficacy of antibiotic treatment, pathogen growth rates and between-organ spread during systemic Salmonella infections. METHODS: We infected mice with isogenic molecularly tagged subpopulations of either a fast-growing WT or a slow-growing ΔaroC Salmonella strain. We monitored viable bacterial numbers and fluctuations in the proportions of each bacterial subpopulation in spleen, liver, blood and mesenteric lymph nodes (MLNs) before, during and after the cessation of treatment with ampicillin and ciprofloxacin. RESULTS: Both antimicrobials induced a reduction in viable bacterial numbers in the spleen, liver and blood. This reduction was biphasic in infections with fast-growing bacteria, with a rapid initial reduction followed by a phase of lower effect. Conversely, a slow and gradual reduction of the bacterial load was seen in infections with the slow-growing strain, indicating a positive correlation between bacterial net growth rates and the efficacy of ampicillin and ciprofloxacin. The viable numbers of either bacterial strain remained constant in MLNs throughout the treatment with a relapse of the infection with WT bacteria occurring after cessation of the treatment. The frequency of each tagged bacterial subpopulation was similar in the spleen and liver, but different from that of the MLNs before, during and after treatment. CONCLUSIONS: In Salmonella infections, bacterial growth rates correlate with treatment efficacy. MLNs are a site with a bacterial population structure different to those of the spleen and liver and where the total viable bacterial load remains largely unaffected by antimicrobials, but can resume growth after cessation of treatment.

A novel obstetric medical device designed for autotransfusion of blood in life threatening postpartum haemorrhage.

Postpartum haemorrhage (PPH) is an obstetric emergency caused by excessive blood loss after delivery, which is the leading cause of maternal mortality worldwide. PPH can lead to volume depletion, hypovolemic shock, anaemia and ultimately death. The prevalence of PPH is disproportionately higher in low resource settings where there is limited access to skilled medical care and safe blood supplies. Current management strategies target both prevention and treatment of PPH however no alternatives currently exist to address the lack of safe blood supplies which are considered essential in emergency obstetrical care. Autotransfusion is used to salvage blood loss in a variety of clinical settings but has never been used in the context of vaginal delivery. We describe the development and testing of a novel device for the collection, filtration and autotransfusion of blood lost due to PPH. The prototype device is inexpensive and easily operated so that it may be practically deployed in low resource settings. The device is comprised of a blood collection drape, a pump apparatus, three leukocyte reduction filters and a reservoir for filtered blood. Preliminary testing demonstrates efficacy of microbial load reduction of up to 97.3%. To reduce cost and improve safety, the device is modular in design such that the drape, tubing, filters and transfusion bag may be stored sterile, used once and discarded; while the pump apparatus may be used indefinitely without the need for sterilisation. Preliminary results indicate the device confers a low cost and potentially effective means of collecting, pumping, filtering and returning blood to a patient following PPH in settings that lack safe blood supplies. This device shows promise as a method of stabilising patients suffering of PPH in low resource settings until definitive treatment is rendered with the ultimate goal of reducing maternal mortality globally.

Impact of prompt intervention in response to positive blood culture results during weekends by collaboration between infectious disease specialists and microbiology laboratory staff.

The purpose of this investigation was to elucidate the impact of prompt intervention for patients whose blood culture results became positive during weekends, as this is not standard care in some countries. A retrospective cohort study was conducted in a tertiary referral hospital. From June 2015, results of positive blood cultures became available during weekends. If infectious disease specialists identified cases of bacteremia on suboptimal antimicrobial coverage, they contacted the primary team for modification of antibiotic treatment. We reviewed patients whose blood culture results became positive during weekends, comparing the pre-intervention (September 2014 to May 2015) and post-intervention (June 2015 to February 2016) periods. In total, 1081 (post-intervention 568 [52.5%]) bacteremia episodes were included (median patient age [interquartile range, IQR]: 72 [60-82] years; men: 625 [57.8%]). During the post-intervention period, 187 (32.9%) bacteremia episodes were detected during weekends. Infectious disease specialists evaluated the positive blood culture results 1, 2, and ≥3 days prior in 77 (13.6%), 88 (15.5%), and 22 (3.9%) cases, respectively. Although the 7- and 30-day mortality did not significantly improve after the intervention, the length of hospital stay (LOS) in the hospital-acquired bacteremia group was significantly reduced during the post-intervention period after controlling for confounders (post- vs. pre-intervention: median days [IQR]: 37 [19-63] vs. 46.5 [24.8-86.3], p = 0.030). Blood culture results became positive during weekends in one-third of bacteremia cases. The LOS was shortened after the intervention in the hospital-acquired bacteremia group. This could be an important antimicrobial stewardship target.

Magnetic nanoparticle-enhanced PCR for the detection and identification of Staphylococcus aureus and Salmonella enteritidis.

This paper evaluated magnetic nanoparticle-enhanced PCR for the detection and identification of Staphylococcus aureus and Salmonella enteritidis. Two different types of magnetic nanoparticles designated MPIO (iron concentration 2.5 mg/ml, size 1 µm) and NP (iron concentration 8.7 mg/ml, size 60 nm), both conjugated with S. aureus or S. enteritidis antibodies were evaluated as an enrichment procedure for PCR-detection of the pathogens in Trypticase Soy Broth, milk, blood and meat broth. Bacterial suspensions (1.5x108 cfu/ml) were prepared and serial diluted 10-1. The MPIO and NP nanoparticles were added, followed by incubation for 1 hour at room temperature, magnetic separation of the pellet, DNA extraction and PCR, targeting the femA and invA sequences. The nanoparticle-free and the NP-supplemented dilutions were positive down to the 1.5x102 cfu/ml concentration for both bacteria. The MPIO-supplemented dilutions were positive down to approx. 2x100 cfu/ml concentration, respectively. Bacteria-free TSB was negative by PCR. MPIO nanoparticles (size 1 µm) enhanced the detection of S. aureus and S. enteritidis by PCR, whilst NP nanoparticles (size 60 nm) did not, thus indicating that the size of the magnetic nanoparticles play a significant role in the enrichment procedure.

Adición de vancomicina al suero de lavado del recuperador de sangre. Efecto sobre la contaminación bacteriana / Vancomycin added to the wash solution of the cell-saver. Effect on bacterial contamination

Objetivos. Comprobar si la adición de bajas dosis de antibiótico (vancomicina) al suero de lavado del recuperador celular reduce la incidencia de contaminación bacteriana del concentrado de hematíes (CH) autógeno recuperado. Material y método. Estudio experimental, aleatorizado, doble ciego, en forma de grupos paralelos, sobre 20 pacientes consecutivos, programados para cirugía de artrodesis vertebral posterior. La hemorragia intraoperatoria se procesó mediante un recuperador de sangre modelo HaemoLite® 2+, en cuyo proceso los hematíes se lavaron según grupo de aleatorización, con suero fisiológico (grupo control) o con suero fisiológico+10μg/ml−1 de vancomicina (grupo vanco). Se recogieron los datos referentes a edad, peso, volumen procesado y recuperado, hemograma, hemocultivo y concentración de vancomicina del CH obtenido e incidencia de fiebre tras la reinfusión. Resultados. El volumen procesado fue 843±403ml y el volumen recuperado 121±29ml, con hemoglobina 10,4±5,0g/dl−1 y hematocrito 29,1±15,9% (media±DE). El hemocultivo del CH recuperado fue positivo a Staphylococcus coagulasa negativo en 5 casos (50%) en el grupo control mientras que fue estéril en todos los casos en el grupo vanco (p=0,016). La diferencia entre la concentración teórica de vancomicina administrada y la determinada en CH recuperado fue de 1,31μg/ml−1 (IC 95% 1,19-1,43; p=0,074). Conclusiones. La adición de vancomicina a una concentración de 10μg/ml−1 en el suero de lavado del recuperador consigue concentraciones similares en la sangre autógena recuperada y permite la eliminación de las bacterias, obteniéndose hemocultivos negativos en todos los casos (AU)

Objectives. The aim of this study is to test whether the addition of a low-dose of antibiotic (vancomycin) to the wash solution (saline) of the cell-saver reduces the incidence of bacterial contamination of the autologous red blood cell (RBCs) concentrate recovered. Material and method. Experimental, randomized, double-blind, parallel group study performed on 20 consecutive patients scheduled for posterior spinal fusion surgery. Intraoperative bleeding was processed through a cell-saver: HaemoLite® 2+, in which the RBCs were washed according to randomization group, with saline (control group) or saline+10μg/ml−1 vancomycin (vanco group). Data regarding age, weight, processed and recovered volume, blood count, blood culture, and vancomycin concentration in RBCs concentrates obtained and incidence of fever after reinfusion were collected. Results. Processed volume was 843±403ml and recovered volume 121±29ml, with haemoglobin concentration 10.4±5.0g/dl−1 and haematocrit 29.1±15.9% (mean±SD). Recovered RBC concentrate cultures were positive for coagulase-negative Staphylococcus in 5 cases (50%) of the control group while all cultures were negative in the vanco group (P=.016). The difference between the theoretical concentration of vancomycin administered and the concentration determined in the recovered RBC concentrate was 1.31μg/ml−1 (95% CI 1.19 to 1.43; P=.074). Conclusions. The addition of vancomycin at a concentration of 10ug/ml−1 to the wash solution of the cell-saver achieved similar concentrations in the autologous blood concentrate recovered allowing for bacterial removal, with negative blood cultures in all cases (AU)

Protective effect of Berberis aristata against peritonitis induced by carbapenem-resistant Escherichia coli in a mammalian model.

OBJECTIVES: Berberis aristata is known to contain a variety of phenolic compounds contributing to its holistic capability of mitigating bacterial multidrug resistance. METHODS: B. aristata stem bark extract was prepared and was characterised using liquid chromatography-mass spectrometry (LC-MS). The antimicrobial efficacy of the extract against carbapenem-resistant Escherichia coli was assessed in vivo in an animal model using Sprague Dawley rats. Microbial counts in blood and urine, physical health status, haematological and biochemical analysis of blood, and histopathology of the kidney were assessed as the study endpoints. RESULTS: An aquo-alcoholic extract of B. aristata (PTRC-2111-A) was found to effectively manage peritonitis induced by carbapenem-resistant E. coli in a rat model at a single post-exposure prophylactic dose of 0.5mg/kg body weight (BW). The extract was also found to show a no observed adverse effect level (NOAEL) up to a dose of 2000mg/kg BW. Physical, immunological, haematological, biochemical and histopathological aberrations were found to be restored to normal in the herbal-treated group at a dose of 0.5mg/kg BW. CONCLUSIONS: The antimicrobial and hepatorenal protective ability of PTRC-2111-A could be attributed to the presence of isoquinoline alkaloids.

Hemolytic capability and expression of a putative haem oxygenase-encoding gene by blood isolates of Candida tropicalis are influenced by iron deprivation and the presence of hemoglobin and erythrocytes.

Although hemolytic activity is known to be a putative virulence factor contributing to candidal pathogenesis, its production by Candida tropicalis, a species closely related to Candida albicans, is poor understood. The present study was undertaken to evaluate the hemolytic activity and the expression level of a putative haem oxygenase encoding gene by blood isolates of C. tropicalis following growth in iron deprivation, and in the presence of hemoglobin and erythrocytes. The lowest values of hemolytic activity were observed in cell-free culture supernatants of isolates growing in iron-restricted medium (RPMI medium and RPMI medium supplemented with iron chelator bathophenanthrolindisulphonic acid). Hemolysis was increased in the presence of either hemoglobin or erythrocytes. Reverse transcriptase PCR analysis showed that the putative haem oxygenase encoding gene (CtHMX1), potentially related with iron uptake, was up-regulated (p < 0.001) following growth in iron deprivation and in the presence of hemoglobin; CtHMX1 was repressed in the presence of human erythrocytes (p < 0.001). Our data suggest that hemoglobin had positive effect in the production of hemolytic factor and gene expression related to iron uptake in C. tropicalis.

Pharmacodynamics of Finafloxacin, Ciprofloxacin, and Levofloxacin in Serum and Urine against TEM- and SHV-Type Extended-Spectrum-ß-Lactamase-Producing Enterobacteriaceae Isolates from Patients with Urinary Tract Infections.

The pharmacodynamics of finafloxacin, ciprofloxacin, and levofloxacin against extended-spectrum-ß-lactamase (ESBL)-producing Enterobacteriaceae isolates were compared. Since quinolones lose activity in acidic media, and particularly in urine, their activities were tested in parallel under conventional conditions and in acidic artificial urine. For this purpose, TEM- and SHV-type ESBL-producing Escherichia coli and Klebsiella pneumoniae strains and their wild-type counterparts were exposed in a modified Grasso model to simulated concentrations of drugs in serum and urine following oral doses of either finafloxacin at 800 mg once a day (q.d.), immediate-release ciprofloxacin at 500 mg twice a day (b.i.d.), extended-release ciprofloxacin at 1,000 mg q.d., or levofloxacin at 500 or 750 mg q.d. The concentrations of the drugs in urine were fitted by compartmental modeling. Bacteria were cultivated in Mueller-Hinton broth (MHB) at pH 7.2 or 5.8 or in artificial urine at pH 5.8. Bacteria were counted every 2 h until 10 h and at 24 h; the areas under the bacterial-count-versus-time curves were calculated. It was found that finafloxacin eliminated all strains within 2 h under all the conditions studied. At all doses studied, ciprofloxacin and levofloxacin were highly active against wild-type strains in MHB at pH 7.2 but lost activity in MHB, and particularly in urine, at pH 5.8. Viable counts of ESBL producers were reduced for 6 to 8 h by 3 log10 titers, but the bacteria regrew thereafter. Ciprofloxacin and levofloxacin were almost inactive against the SHV producer grown in artificial urine. We conclude that pharmacodynamic models using artificial urine may mirror the physiology of urinary tract infections more closely than those using conventional media. In contrast to ciprofloxacin and levofloxacin, finafloxacin gained activity in this model at an acidic pH, maintained activity in artificial urine, and was active against TEM and SHV producers.

Fifteen-minute consultation: the complexities of empirical antibiotic selection for serious bacterial infections-a practical approach.

Potentially life-threatening infections require immediate antibiotic therapy. Most early stage antibiotic treatment for these infections is empirical, that is, covering a range of possible target bacteria while awaiting culture results. Empirical antibiotic regimens need to reflect the epidemiology of most likely causative bacteria, type of infection and patient risk factors. Summary data from relevant isolates in similar patients help to identify appropriate empirical regimens. At present, such data are mostly presented as hospital or other aggregate antibiograms, showing antimicrobial susceptibility testing results by bacterial species. However, a more suitable method is to calculate weighted incidence syndromic combination antibiograms for different types of infections and regimens, allowing head-to-head comparisons of empirical regimens. Once there is confirmatory or negative microbiological evidence of infection, empirical regimens should be adapted to the identified bacterial species and susceptibilities or discontinued.

Immunization with a 22-kDa outer membrane protein elicits protective immunity to multidrug-resistant Acinetobacter baumannii.

A. baumannii infections are becoming more and more serious health issues with rapid emerging of multidrug and extremely drug resistant strains, and therefore, there is an urgent need for the development of nonantibiotic-based intervention strategies. This study aimed at identifying whether an outer membrane protein with molecular weight of about 22 kDa (Omp22) holds the potentials to be an efficient vaccine candidate and combat A. baumannii infection. Omp22 which has a molecule length of 217 amino acids kept more than 95% conservation in totally 851 reported A. baumannii strains. Recombinant Omp22 efficiently elicited high titers of specific IgG in mice. Both active and passive immunizations of Omp22 increased the survival rates of mice, suppressed the bacterial burdens in the organs and peripheral blood, and reduced the levels of serum inflammatory cytokines and chemokines. Opsonophagocytosis assays showed in vitro that Omp22 antiserum had highly efficient bactericidal activities on clonally distinct clinical A. baumannii isolates, which were partly complements-dependent and opsonophagocytic killing effects. Additionally, administration with as high as 500 µg of Omp22 didn't cause obvious pathological changes in mice. In conclusion, Omp22 is a novel conserved and probably safe antigen for developing effective vaccines or antisera to control A. baumannii infections.

Haematospirillum jordaniae gen. nov., sp. nov., isolated from human blood samples.

A Gram-negative, aerobic, motile, spiral-shaped bacterium, strain H5569(T), was isolated from a human blood sample. Phenotypic and molecular characteristics of the isolate were investigated. Optimal growth was found to occur at 35 °C under aerobic conditions on Heart Infusion Agar supplemented with 5 % rabbit blood. The major fatty acids present in the cells were identified as C16:0, C16:1ω7c and C18:1ω7c. The predominant respiratory quinone was found to be ubiquinone-Q10. The G+C content of genomic DNA for strain H5569(T) was found to be 49.9 %. Based on 16S rRNA gene sequence analysis results, 13 additional isolates were also analysed in this study. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the organism, represented by strain H5569(T), forms a distinct lineage within the family Rhodospirillaceae, closely related to two Novispirillum itersonii subspecies (93.9-94.1 %) and two Caenispirillum sp. (91.2-91.6 %). Based on these results, the isolate H5569(T) is concluded to represent a new genus and species for which the name Haematospirillum jordaniae gen. nov., sp. nov. is proposed. The type strain is H5569(T) (=DSM(T) 28903 = CCUG 66838(T)).

Antimicrobial susceptibility of clinical Enterobacteriaceae isolates at the emergency department in a regional hospital: A threat of extended spectrum beta-lactamase-producers among nursing home residents.

BACKGROUND/PURPOSE: The prevalence of extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in nursing home residents has rarely been reported in Taiwan. METHODS: A retrospective study was performed at medical wards of a district hospital at southern Taiwan between July 2009 and June 2011. Patients were included if they were older than 18 years, admitted via the emergency department, and their blood, sputum, or urine culture revealed the growth of Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis. From each patient only the first isolate from the infection site was included. Antimicrobial susceptibility was determined using the disc diffusion method. RESULTS: Overall, 827 patients were included, with 354 (42.8%) coming from the community and 473 (57.2%) referred from a nursing home. Of the isolates acquired in nursing home, 45.5% (215/473) harbored ESBL. By contrast, 20.6% (73) of 354 isolates acquired in the community exhibited the ESBL production phenotype (p < 0.001). Of the isolates obtained from blood, urine, or sputum, 28.2% (37/131), 36.0% (208/578), or 36.4% (43/118) harbored ESBL, respectively, whereas 41% (211) of 515 E. coli isolates, 34.3% (72) of 210 K. pneumoniae, and 4.9% (5) of 102 P. mirabilis had ESBL. In general, the isolates from a nursing home or those with ESBL had lower antimicrobial susceptibility rates than those from the community or those without ESBL production. Only amikacin, piperacillin/tazobactam, ertapenem, and imipenem/meropenem were active against >90% Enterobacteriaceae isolates, irrespective of ESBL production. CONCLUSION: ESBL production was common among clinical Enterobacteriaceae isolates, especially E. coli or those isolated from nursing home residents.