Blood and liver telomere length, mitochondrial DNA copy number, and hepatic gene expression of mitochondrial dynamics in mid-lactation cows supplemented with l-carnitine under systemic inflammation

The current study was conducted to examine the effect of l-carnitine (LC) supplementation on telomere length and mitochondrial DNA copy number (mtDNAcn) per cell in mid-lactation cows challenged by lipopolysaccharide (LPS) in blood and liver. The mRNA abundance of 31 genes related to inflammation, oxidative stress, and the corresponding stress response mechanisms, the mitochondrial quality control and the protein import system, as well as the phosphatidylinositol 3-kinase/protein kinase B pathway, were assessed using microfluidics integrated fluidic circuit chips (96.96 dynamic arrays). In addition to comparing the responses in cows with or without LC, our objectives were to characterize the oxidative and inflammatory status by assessing the circulating concentration of lactoferrin (Lf), haptoglobin (Hp), fibrinogen, derivates of reactive oxygen metabolites (dROM), and arylesterase activity (AEA), and to extend the measurement of Lf and Hp to milk. Pluriparous Holstein cows were assigned to either a control group (CON, n = 26) or an LC-supplemented group (CAR; 25 g LC/cow per day; d 42 ante partum to d 126 postpartum (PP), n = 27). On d 111 PP, each cow was injected intravenously with LPS (Escherichia coli O111:B4, 0.5 µg/kg). The mRNA abundance was examined in liver biopsies of d -11 and +1 relative to LPS administration. Plasma and milk samples were frequently collected before and after the challenge. After LPS administration, circulating plasma fibrinogen and serum dROM concentrations increased, whereas AEA decreased. Moreover, serum P4 initially increased by 3 h after LPS administration and declined thereafter irrespective of grouping. The Lf concentrations increased in both groups after LPS administration, with the CAR group showing greater concentrations in serum and milk than the CON group. After LPS administration, telomere length in blood increased, whereas mtDNAcn per cell decreased; however, both remained unaffected in liver. For mitochondrial protein import genes, the hepatic mRNA abundance of the translocase of the mitochondrial inner membrane (TIM)-17B was increased in CAR cows. Moreover, TIM23 increased in both groups after LPS administration. Regarding the mRNA abundance of genes related to stress response mechanisms, 7 out of 14 genes showed group × time interactions, indicating a (local) protective effect due to the dietary LC supplementation against oxidative stress in mid-lactating dairy cows. For mtDNAcn and telomere length, the effects of the LPS-induced inflammation were more pronounced than the dietary supplementation of LC. Dietary LC supplementation affected the response to LPS primarily by altering mitochondrial dynamics. Regarding mRNA abundance of genes related to the mitochondrial protein import system, the inner mitochondrial membrane translocase (TIM complex) seemed to be more sensitive to dietary LC than the outer mitochondrial membrane translocase (TOM complex).

Analysis of transmission-related third-generation cephalosporin-resistant Enterobacterales by electronic data mining and core genome multi-locus sequence typing

BACKGROUND

To contain intra-hospital transmission of third-generation cephalosporin-resistant Enterobacterales (3GCR-E), contact isolation precautions are recommended.

AIM

To quantify transmissions of 3GCR Escherichia coli and 3GCR Klebsiella pneumoniae within a hospital.

METHODS

An automated outbreak detection system (AODS) was used to identify clusters (N≥2) of 3GCR Enterobacterales for the years 2016, 2018 and 2020. Clusters were defined by phenotypic agreement of microbiological results and spatial and temporal relationship. Core genome multi-locus sequence typing (cgMLST) was used to confirm whether the cluster isolates were transmitted between patients.

FINDINGS

A total of 4343 3GCR E. coli and 1377 K. pneumoniae isolates were analysed. Among the 3GCR E. coli isolates, the AODS identified 304 isolates as cluster isolates, the median cluster size was two (range: 2-5). The cgMLST analysis revealed that a total of 23 (7.5%) 3GCR E. coli cluster isolates were transmission-associated, of which 20 isolates (87%) were detected in intensive care patients. Among the 3GCR K. pneumoniae isolates, the AODS identified 73 isolates as cluster isolates, the median cluster size was two (range: 2-4). CgMLST revealed that 35 (48%) 3GCR K. pneumoniae cluster isolates were transmission associated, of which 27 isolates (77%) were detected in intensive care patients.

CONCLUSION

For 3GCR K. pneumoniae, cgMLST confirmed the AODS results more frequently than for 3GCR E. coli. Therefore, contact isolation precautions for 3GCR K. pneumoniae may be appropriate on intensive care units, but only in certain circumstances, such as outbreaks, for Enterobacterales with lower transmissibility, such as E. coli.

Antimicrobial Activity of Ceftolozane-Tazobactam, Ceftazidime-Avibactam, and Cefiderocol against Multidrug-Resistant Pseudomonas aeruginosa Recovered at a German University Hospital

Multidrug-resistant (MDR) Pseudomonas aeruginosa increasingly causes health care-associated infections. In this study, we determined the activity of ceftolozane-tazobactam, ceftazidime-avibactam, and cefiderocol against 223 MDR P. aeruginosa clinical isolates recovered from 2013 to 2017 at the University Hospital Frankfurt by using MIC test strips. Furthermore, we evaluated the presence of genes encoding major β-lactamases, such as VIM, IMP, NDM, GIM, SPM, and KPC; the extended spectrum β-lactamase (ESBL)-carbapenemase GES; and the virulence-associated traits ExoS and ExoU, as in particular ExoU is thought to be associated with poor clinical outcome. For MDR P. aeruginosa isolates, the MIC50/MIC90 values of ceftolozane-tazobactam, ceftazidime-avibactam, and cefiderocol were 8/>256 mg/L, 16/>256 mg/L, and 0.25/1 mg/L, respectively. Cefiderocol showed the highest susceptibility rate (97.3%) followed by ceftazidime-avibactam (48.4%) and ceftolozane-tazobactam (46.6%). In 81 (36.3%) isolates, carbapenemase gene blaVIM was detected, and in 5 (2.2%) isolates, blaGES was detected (with a positive association of exoU and blaVIM). More than half of the isolates belong to the so-called international P. aeruginosa "high-risk" clones, with sequence type 235 (ST235) (24.7%) being the most prevalent. This study underlines that ceftolozane-tazobactam, ceftazidime-avibactam, and cefiderocol are important options for the treatment of infections due to MDR P. aeruginosa, with cefiderocol currently being the most active available antipseudomonal β-lactam agent. According to our clinical experience, the outcome of cefiderocol therapy (8 patients) was favorable especially in cases of MDR P. aeruginosa-associated complicated urinary tract infections. IMPORTANCE After testing ceftolozane-tazobactam, ceftazidime-avibactam, and cefiderocol against a collection of 233 multidrug-resistant (MDR) Pseudomonas aeruginosa, we showed that cefiderocol is the most active antipseudomonal β-lactam agent (susceptibility rates were 46.6%, 48.4%, and 97.4%, respectively). The most prevalent one was sequence type 235 (ST235) (24.7%), followed by ST244, ST175, and ST233, with all belonging to the top 10 P. aeruginosa high-risk clones with worldwide distribution. Our data indicate that during surveillance studies special attention should be paid to the MDR and highly virulent VIM- and ExoU-producing variant of ST235. Furthermore, in the case of infections caused by carbapenemase-producing MDR P. aeruginosa, cefiderocol is the preferred treatment option, while outcomes of complicated urinary tract infections and hospital-acquired pneumonia with cefiderocol were favorable.

Blood and adipose tissue steroid metabolomics and mRNA expression of steroidogenic enzymes in periparturient dairy cows differing in body condition

In high-yielding dairy cows, the rapidly increasing milk production after parturition can result in a negative nutrient balance, since feed intake is insufficient to cover the needs for lactation. Mobilizing body reserves, mainly adipose tissue (AT), might affect steroid metabolism. We hypothesized, that cows differing in the extent of periparturient lipomobilization, will have divergent steroid profiles measured in serum and subcutaneous (sc)AT by a targeted metabolomics approach and steroidogenic enzyme profiles in scAT and liver. Fifteen weeks antepartum, 38 multiparous Holstein cows were allocated to a high (HBCS) or normal body condition (NBCS) group fed differently until week 7 antepartum to either increase (HBCS BCS: 3.8 ± 0.1 and BFT: 2.0 ± 0.1 cm; mean ± SEM) or maintain BCS (NBCS BCS: 3.0 ± 0.1 and BFT: 0.9 ± 0.1 cm). Blood samples, liver, and scAT biopsies were collected at week -7, 1, 3, and 12 relative to parturition. Greater serum concentrations of progesterone, androsterone, and aldosterone in HBCS compared to NBCS cows after parturition, might be attributed to the increased mobilization of AT. Greater glucocorticoid concentrations in scAT after parturition in NBCS cows might either influence local lipogenesis by differentiation of preadipocytes into mature adipocytes and/or inflammatory response.

Detection of 11 beta-hydroxysteroid dehydrogenase type 1, the glucocorticoid and mineralocorticoid receptor in various adipose tissue depots of dairy cows supplemented with conjugated linoleic acids

Early lactating cows mobilize adipose tissue (AT) to provide energy for milk yield and maintenance and are susceptible to metabolic disorders and impaired immune response. Conjugated linoleic acids (CLA), mainly the trans-10, cis-12 isomer, reduce milk fat synthesis and may attenuate negative energy balance. Circulating glucocorticoids (GC) are increased during parturition in dairy cows and mediate differentiating and anti-inflammatory effects via glucocorticoid (GR) and mineralocorticoid receptors (MR) in the presence of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1). Activated GC are the main ligands for both receptors in AT; therefore, we hypothesized that tissue-specific GC metabolism is effected by varying amounts of GR, MR and 11βHSD1 and/or their localization within AT depots. Furthermore, the lipolytic and antilipogenic effects of CLA might influence the GC/GR/MR system in AT. Therefore, we aimed to localize GR and MR as well as the expression pattern and activity of 11βHSD1 in different AT depots during early lactation in dairy cows and to identify potential effects of CLA. Primiparous German Holstein cows were divided into a control (CON) and a CLA group. From day 1 post-partum (p.p.) until sample collection, the CLA group was fed with 100 g/d CLA (contains 10 g each of the cis-9, trans-11 and the trans-10, cis-12-CLA isomers). CON cows (n = 5 each) were slaughtered on day 1, 42 and 105 p.p., while CLA cows (n = 5 each) were slaughtered on day 42 and 105 p.p. Subcutaneous fat from tailhead, withers and sternum, and visceral fat from omental, mesenteric and retroperitoneal depots were sampled. The localization of GR and 11βHSD1 in mature adipocytes - being already differentiated - indicates that GC promote other effects via GR than differentiation. Moreover, MR were observed in the stromal vascular cell fraction and positively related to the pre-adipocyte marker Pref-1. However, only marginal CLA effects were observed in this study.

Murine solid tumours as a novel model to study bacterial biofilm formation in vivo

Bacteria of many species are able to invade and colonize solid tumours in mice. We have focused on Salmonella enterica serovar Typhimurium. Detailed analysis revealed that such tumour-invading Salmonella form biofilms, thus providing a versatile in vivo test system for studying bacterial phenotypes and host-pathogen interactions. It appears that biofilm formation by S. typhimurium is induced as a defence against the immune system of the host, and in particular against neutrophils. Further, we extended our work to the clinically more relevant biofilm infection by Pseudomonas aeruginosa. The induction of P. aeruginosa biofilms in neoplastic tissue appears to be elicited as a reaction against the immune system. Reconstitution experiments reveal that T cells are responsible for biofilm induction. Isogenic mutants that are no longer able to form biofilms can be used for comparison studies to determine antimicrobial resistance, especially therapeutic efficacy against P. aeruginosa located in biofilms.

Lactation driven dynamics of adiponectin supply from different fat depots to circulation in cows

Adipose tissue (AT) depots are heterogeneous in terms of morphology and adipocyte metabolism. Adiponectin, one of the most abundant adipokines, is known for its insulin sensitizing effects and its role in glucose and lipid metabolism. Little is known about the presence of adiponectin protein in visceral (vc) and subcutaneous (sc) AT depots. We assessed serum adiponectin and adiponectin protein concentrations and the molecular weight forms in vc (mesenterial, omental, and retroperitoneal) and sc (sternum, tail-head, and withers) AT of primiparous dairy cows during early lactation. Primiparous German Holstein cows (n = 25) were divided into a control (CON) and a conjugated linoleic acid (CLA) group. From day 1 of lactation until slaughter, CLA cows were fed 100 g of a CLA supplement/d (approximately 6% of cis-9, trans-11 and trans-10, cis-12 isomers each), whereas the CON cows received 100 g of a fatty acid mixture/d instead of CLA. Blood samples from all animals were collected from 3 wk before calving until slaughter on day 1 (n = 5, CON cows), 42 (n = 5 each of CON and CLA cows), and 105 (n = 5 each of CON and CLA cows) of lactation when samples from different AT depots were obtained. Adiponectin was measured in serum and tissue by ELISA. In all AT depots adiponectin concentrations were lowest on day 1 than on day 42 and day 105, and circulating adiponectin reached a nadir around parturition. Retroperitoneal AT had the lowest adiponectin concentrations; however, when taking total depot mass into consideration, the portion of circulating adiponectin was higher in vc than sc AT. Serum adiponectin was positively correlated with adiponectin protein concentrations but not with the mRNA abundance in all fat depots. The CLA supplementation did not affect adiponectin concentrations in AT depots. Furthermore, inverse associations between circulating adiponectin and measures of body condition (empty body weight, back fat thickness, and vc AT mass) were observed. In all AT depots at each time, adiponectin was present as high (approximately 300 kDa) and medium (approximately 150 kDa) molecular weight complexes similar to that of the blood serum. These data suggest differential contribution of AT depots to circulating adiponectin.

Short communication: circulating and milk adiponectin change differently during energy deficiency at different stages of lactation in dairy cows

Adiponectin, one of the most abundant adipokines in circulation, is known for its role in regulation of body metabolism. The aim of this study was to evaluate the effects of a negative energy balance (NEB) at 2 stages of lactation (lactational NEB at the onset of lactation and an induced NEB by feed restriction near 100 d of lactation) on circulating adiponectin concentrations. We also investigated the effect of feed restriction on adiponectin concentrations in milk and the relationships of blood and milk adiponectin with selected plasma or milk variables and with measures of body condition. Plasma adiponectin was measured in 50 multiparous Holstein dairy cows throughout 3 experimental periods [i.e., period 1=3 wk antepartum up to 12 wk postpartum, period 2=3 wk of feed restriction starting at around 100 d in milk with a control (n=25) and feed-restricted group (50% of energy requirements; n=25), and period 3=subsequent realimentation period for 8 wk]. Milk adiponectin was investigated among 21 multiparous cows at wk 2 and wk 12 of period 1 and wk 2 of period 2. Adiponectin concentrations in plasma and skim milk were measured using an in-house ELISA specific for bovine adiponectin. Major changes in circulating adiponectin concentrations were observed during the periparturient period, whereas energy deficiency during established lactation at around 100 d in milk and subsequent refeeding did not affect plasma adiponectin. Together with lower adiponectin concentrations in milk (µg/mL), the reduction in milk yield led to decreased adiponectin secretion via milk (mg/d) at the second week of feed restriction. Irrespective of time and treatment, milk adiponectin represented about 0.002% of total milk protein. Mean adiponectin concentrations in milk (0.61 ± 0.03 µg/mL) were about 92% lower than the mean plasma adiponectin concentrations (32.1 ± 1.0 µg/mL). The proportion of the steady-state plasma adiponectin pool secreted daily via milk was 2.7%. In view of the similar extent of NEB in both periods of energy deficiency, decreasing adiponectin concentrations seems important for accomplishing the adaptation to the rapidly increasing metabolic rates in early lactation, whereas the lipolytic reaction toward feed restriction-induced NEB during established lactation seems to occur largely independent of changes in circulating adiponectin.

Characterization of the dynamics of fat cell turnover in different bovine adipose tissue depots

In many but not all high producing cows, the energy requirements for milk yield and maintenance exceed energy intake by voluntary feed intake during early lactation. Prioritizing milk secretion, body reserves mainly from adipose tissue are mobilized and imply an increased risk for metabolic diseases. Reducing the energy output via milk by decreasing the milk fat content through feed supplements containing conjugated linoleic acids (CLAs) may attenuate the negative energy balance during this period. In two separate trials, variables characterizing fat cell turnover were investigated in different subcutaneous and visceral fat depots from primiparous heifers (n = 25) during early lactation, and subcutaneous fat from non-lactating, over-conditioned heifers (n = 12) by immunohistochemistry. The portion of apoptotic adipocytes was consistently greater than that of proliferating cells and preadipocytes; the sporadically observed effects of CLA were limited to visceral fat. Lactating heifers had more apoptosis and less preadipocytes than non-lactating heifers.

Development, validation, and pilot application of a semiquantitative Western blot analysis and an ELISA for bovine adiponectin

Adiponectin is an adipose tissue-derived glycoprotein circulating as highly abundant multimers. It regulates glucose metabolism and insulin sensitivity. In ruminants, valid data about serum concentrations and tissue-specific protein expression are lacking, and we, therefore, aimed to generate a polyclonal antibody against bovine adiponectin to apply it in immunodetection. The specificity of the purified anti-adiponectin antibody was established by Western blot analysis with the use of reducing and denaturing conditions applied to both the purified protein and the bovine serum samples. Besides bovine serum, the applicability of the antibody for immunodetection of adiponectin was confirmed for the supernatant fluid of in vitro-differentiated bovine adipocytes, for protein extracts from bovine adipose tissue, and also in a multispecies comparison: bands comparable in size with monomeric bovine adiponectin were obtained under denaturing conditions in serum of camel, horse, human, mouse, pig, roe deer, and sheep. In addition, when used in immunohistochemistry on bovine adipose tissue sections, a characteristic adipocyte-specific staining pattern was obtained with this antibody. The antibody was used for establishing a semiquantitative Western blot procedure and the development of an ELISA. Both methods were extensively validated and were first applied to characterize the serum adiponectin concentrations in multiparous dairy cows during the transition from pregnancy to lactation, that is, 3 wk before until 5 wk after calving. With both assays a time effect (P = 0.017, P = 0.026, respectively) with lowest values at the day of parturition was observed. We thus established 2 useful tools to validly assess bovine adiponectin at the protein level.

Physiological and conjugated linoleic acid-induced changes of adipocyte size in different fat depots of dairy cows during early lactation

The aim of this study was to investigate the effects of lactation and conjugated linoleic acid (CLA) supplementation on adipocyte sizes of subcutaneous (s.c.) and visceral (VC) fat depots in primiparous dairy cows during the first 105 d in milk (DIM). German Holstein heifers (n=25) were divided into a control (CON) and a CLA group. From 1 DIM until sample collection, CLA cows were fed 100g of CLA supplement/d (about 6% of c9,t11 and t10,c12 isomers each), whereas the CON cows received 100g of fatty acid mixture/d instead of CLA. The CON cows (n=5 each) were slaughtered at 1, 42, and 105 DIM, and the CLA cows (n=5 each) were slaughtered at 42 and 105 DIM. Adipose tissues from 3s.c. depots (tailhead, withers, and sternum) and from 3 VC depots (omental, mesenteric, and retroperitoneal) were sampled. Hematoxylin-eosin staining was done to measure adipocyte area (μm(2)). Retroperitoneal adipocyte sizes were mostly larger than adipocytes from the other sites, independent of lactation time and treatment. Significant changes related to duration of lactation were limited to retroperitoneal fat: adipocyte sizes were significantly smaller at 105 DIM than at 1 DIM in CON cows. Adipocyte sizes were decreased in s.c. depots from the tailhead at 105 DIM and from the sternum at 42 DIM in CLA versus CON cows, whereas for VC depots, adipocyte sizes were decreased in mesenteric fat at 42 and 105 DIM, and in omental and retroperitoneal fat, at 105 DIM in CLA versus CON cows. Within the CLA group, adipocyte sizes were smaller in the s.c. depot from the tailhead at 105 DIM than at 42 DIM. Adipocyte sizes and depot weights were significantly correlated in s.c. depots (r=0.795) in the CLA group and in retroperitoneal fat both in the CON (r=0.698) and the CLA (r=0.723) group. In conclusion, CLA-induced decreases in adipocyte size indicate lipolytic or antilipogenic effects of CLA, or both effects, on adipose tissue in primiparous dairy cows.

Evaluation of the E test for the assessment of synergy of antibiotic combinations against multiresistant Pseudomonas aeruginosa isolates from cystic fibrosis patients

The determination of synergistic effects of antimicrobial drug combinations can lead to improved therapeutic options in the antibiotic treatment of cystic fibrosis patients who are chronically infected with multiresistant Pseudomonas aeruginosa isolates. The aim of this study was to evaluate the performance of the E test versus the standard agar dilution checkerboard susceptibility test in the assessment of synergy and, in addition, to determine the activity of two antimicrobial combinations against 163 multiresistant P. aeruginosa isolates from cystic fibrosis patients. The agreement between the checkerboard method and the E test was excellent (>90%) for nonmucoid as well as mucoid isolates from cystic fibrosis patients. The rate of synergy was higher for the antibiotic combination of ceftazidime and tobramycin (28.8% of the cystic fibrosis strains) than for the combination of meropenem and tobramycin (19.0%). However, the probability of synergy for the second antibiotic combination increased significantly when the synergy of the first antibiotic combination had already been demonstrated (Fischer's exact test, p=0.049). The results show that the E test is a valuable and practical method for routine microbiological diagnostics and can aid in the selection of improved antibiotic options in the treatment of cystic fibrosis patients chronically infected with P. aeruginosa.

Comparison of the Micronaut Merlin automated broth microtiter system with the standard agar dilution method for antimicrobial susceptibility testing of mucoid and nonmucoid Pseudomonas aeruginosa isolates from cystic fibrosis patients

The aim of this study was to compare a commercially available automated broth microdilution system (Merlin; Micronaut, Germany) with the standard agar dilution method for susceptibility testing of pulmonary isolates from cystic fibrosis patients. Accurate susceptibility testing of bacterial isolates from cystic fibrosis patients is known to pose problems. Although commercially available automated test systems could facilitate susceptibility testing of such isolates in routine diagnostics, these systems have not been recommended thus far. However, a pilot study recently indicated that the Merlin system, which is based on an endpoint measurement rather than on growth curves, might be applicable in the susceptibility testing of isolates from cystic fibrosis patients. In the present study, the Merlin system was further evaluated using an extended panel of nonmucoid and mucoid Pseudomonas aeruginosa isolates. The results showed that the MICs obtained with the Merlin system tended to be lower than those obtained with the agar dilution method, a finding that became increasingly apparent when mucoid Pseudomonas aeruginosa strains were tested. The correlation coefficients (r values) of the MIC results for all strains tested were between 0.6 and 0.8 for five of the seven antimicrobial agents, with r values exceeding 0.8 for only meropenem and ciprofloxacin. However, since the overall rate of serious discrepancies was within an acceptable range, the Merlin system appears to be applicable for routine clinical use in susceptibility testing of P. aeruginosa isolates from cystic fibrosis patients.

Evaluation of the Merlin, Micronaut system for automated antimicrobial susceptibility testing of Pseudomonas aeruginosa and Burkholderia species isolated from cystic fibrosis patients

Since accurate antimicrobial susceptibility testing of bacterial cystic fibrosis isolates is known to be problematic and an optimal in vitro testing method has not yet been evaluated, the study presented here was conducted to compare the performance of the reference agar dilution method and broth microdilution with a commercially available automated susceptibility test system (Merlin; Micronaut, Germany). In this pilot study, the susceptibility of 70 clinical strains of Pseudomonas aeruginosa and Burkholderia cepacia-like organisms to nine antimicrobial agents was tested using these methods. Susceptibility results generated by broth microdilution (both automated and according to the National Committee for Clinical Laboratory Standards recommendations) were demonstrated to be of good reproducibility, and they compared favourably to the time- and material-consuming standard agar dilution reference method, especially after a prolonged incubation time (48 h).

Structural and functional cellular changes induced by Burkholderia pseudomallei rhamnolipid

In this study we report that extracellular Burkholderia pseudomallei rhamnolipid induced cytopathic changes characterized by retraction, rounding up, and, finally, detachment in phagocytic and nonphagocytic cell lines. These changes were due to a progressive reorganization of the F-actin network resulting in impaired cell cycle progression and a reduced phagocytic function of macrophages.

Fatal outcome of lung transplantation in cystic fibrosis patients due to small-colony variants of the Burkholderia cepacia complex

The aim of this study was to investigate the possible role of small-colony variant morphotypes of Burkholderia cepacia-like organisms in infectious complications in cystic fibrosis patients following lung transplantation. Respiratory tract specimens from 470 cystic fibrosis patients were screened over a 22-month period for Burkholderia cepacia-like organisms. Nineteen patients were positive for these organisms, eight of whom harboured small-colony-variant morphotypes. Three patients underwent bilateral lung transplantation during the study, two of whom harboured small-colony variants in addition to clonally identical wildtypes of Burkholderia multivorans and Burkholderia cepacia genomovar III prior to lung transplantation. Both patients developed fatal systemic infections post transplantation due to small-colony variants. In vitro testing revealed that small-colony variants exhibited increased serum resistance in comparison to wildtypes. The results of this study indicate that diagnostic efforts should be undertaken to carefully identify small-colony variants of Burkholderia cepacia complex, since they might be an indicator of poor post-transplantation outcome in patients with cystic fibrosis.

Tremor-correlated cortical activity in essential tremor

BACKGROUND

In patients with parkinsonian resting tremor, tremor-correlated activity in the contralateral sensorimotor cortex has been studied by both magnetoencephalography (MEG) and electroencephalography (EEG). In essential tremor, MEG failed to detect cortical involvement. The objective of this study was to investigate whether EEG recording can reveal tremor-correlated cortical activity in patients with essential tremor or enhanced physiological tremor.

METHODS

Seven patients with essential tremor and three patients with enhanced physiological tremor participated in the study. Unilateral postural tremor was activated by wrist extension on the right or on the left side. Electromyography (EMG) signals arising from the wrist extensor and flexor muscles, and a high-resolution EEG were recorded simultaneously. Coherences between the time series of the rectified tremor EMG and the EEG were estimated.

FINDINGS

In five of nine arms with essential tremor, we found highly significant coherences at the tremor frequency between the tremor EMG and the EEG. Isocoherence maps illustrating the topography of significant coherences over the scalp showed that the maximum coherences were located over the contralateral sensorimotor cortex. In the patients with enhanced physiological tremor, we were unable to detect consistent significant corticomuscular coherences at the tremor frequency.

INTERPRETATION

Using simultaneous EEG-EMG recordings, we showed that significant corticomuscular coherences at the tremor frequency can be found in essential tremor. This finding contrasts with a recent study based on MEG recordings. The results suggest that the sensorimotor cortex is involved in the generation of essential tremor, in a similar way to that previously shown in parkinsonian resting tremor.

Tremor-correlated cortical activity detected by electroencephalography

OBJECTIVE

In this study we investigated whether cortical activity related to Parkinsonian resting tremor can be detected by electroencephalography (EEG).

METHODS

Seven patients with idiopathic Parkinson's disease suffering from unilateral tremor participated in the study. Electromyography (EMG) signals arising from the wrist extensor and flexor muscles as well as a high resolution EEG were recorded simultaneously. Coherencies between EEG and EMG were calculated.

RESULTS

In all patients, we found highly significant coherencies at the tremor frequency or its first harmonic between the tremor EMG and contralateral EEG channels. There were no significant coherencies between the tremor EMG and ipsilateral EEG channels. Isocoherency maps illustrating the topography of the coherencies over the scalp showed that the maximum coherencies were situated over the cortical motor areas. In one case, a high coherency was also found over the parietal cortex.

CONCLUSIONS

The results show for the first time that tremor-correlated cortical activity can be detected by electroencephalography. The findings underline that motor areas of the cerebral cortex are involved in the neuronal network generating resting tremor in Parkinson's disease.

Highly resistant Burkholderia pseudomallei small colony variants isolated in vitro and in experimental melioidosis

Burkhloderia pseudomallei is the causative agent of melioidosis, a disease in which treatment failures and relapses are common. This study reports on slow growing B. pseudomallei 'small colony variants' (SCVs), isolated either in vitro after exposure to ceftazidime, ciprofloxacin or gentamicin or from the spleen and liver in a mouse model of melioidosis after treatment with ceftazidime. Interestingly, SCVs isolated by either method or antimicrobial agent showed a significant increase in the minimal inhibitory concentrations of various unrelated classes of antimicrobial agents. B. pseudomallei SCVs did not differ from their parental strains in standard biochemical profiles, nor by pulsed field gel electrophoresis or electron microscopy. Although the SCV phenotype was stable throughout numerous passages on antibiotic-free solid media, revertants with the parental colony morphology and, most importantly, with the parental susceptibility pattern occurred. These revertants led to rapid overgrowth of SCVs in liquid media without added antibiotics. Future studies will have to determine the clinical relevance of B. pseudomallei SCVs especially in treatment failure and relapse of infection.

Small-colony variants of Pseudomonas aeruginosa in cystic fibrosis

In the context of chronic lung infection due to Pseudomonas aeruginosa in cystic fibrosis (CF), attention has been focused on the presence of the most common mucoid phenotype. In this study, the presence of small-colony variants (SCVs) of P. aeruginosa in respiratory tract specimens from patients with CF was investigated, and the clinical conditions predisposing to SCVs were analyzed. P. aeruginosa SCVs were isolated from 33 of 86 P. aeruginosa-positive CF patients over a 2-year period. Fast-growing revertants with larger surface colonies could be isolated from SCV populations. Electron microscopy revealed no significant difference in cell size or morphology. MICs of a broad range of antipseudomonas agents for SCVs were two- to eightfold higher than values for revertants. Recovery of SCVs was correlated with parameters revealing poor lung function and was significantly associated with daily inhalation of tobramycin or colistin.

Characterization of a murine model of melioidosis: comparison of different strains of mice

Melioidosis is an infectious disease caused by the saprophytic gram-negative rod Burkholderia pseudomallei. The aim of this study was to establish and characterize a murine model of melioidosis to provide a basis for further investigations on the pathogenesis of the disease. After intravenous infection with B. pseudomallei, C57BL/6 mice were found to be significantly more resistant than BALB/c mice. There was a marked organotropism of B. pseudomallei for the spleen and liver in both strains of mice, with the highest bacterial load in the spleen. Electron microscopic investigations of the spleen clearly demonstrated intracellular replication within membrane-bound phagosomes. Electron micrographs of the liver provided evidence that B. pseudomallei-containing phagosomes in hepatocytes fuse with lysosomes, leading to degradation of bacteria. In both strains of mice, the course of infection was highly dependent on the infective dose and the bacterial strain used, ranging from death within a few days to death after several weeks. In comparison with BALB/c mice, the bacterial counts in C57BL/6 mice were decreased 12 h after infection, which is suggestive of an innate immune mechanism against B. pseudomallei in this early phase of infection contributing to the lower susceptibility of C57BL/6 mice. BALB/c mice developed a more pronounced lymphopenia, granulocytosis, and splenomegaly at a lower infective dose compared to C57BL/6 mice. Analysis of the antibody response against B. pseudomallei 11 days after infection revealed a significantly higher immunoglobulin G2A (IgG2a)/IgG1 ratio in C57BL/6 mice than in BALB/c mice, indicating that a T helper type 1 immune response is associated with resistance to infection with B. pseudomallei.

Purification and characterization of a cytotoxic exolipid of Burkholderia pseudomallei

Burkholderia pseudomallei is the causative agent of melioidosis, an infectious disease, which is increasingly recognized as an important public health problem in various tropical regions. This study describes the identification and characterization of a heat-stable extracellular toxin of B. pseudomallei. After cultivation of B. pseudomallei in liquid media, the heated cell-free supernatant was concentrated by ultrafiltration. The concentrate exhibited a cytotoxic and hemolytic activity which showed remarkable resistance against alkaline and acidic treatments. For further purification, reversed-phase chromatography using a fast-performance liquid chromatography system was performed. After elution with an acetonitrile gradient, a single cytotoxic and hemolytic peak was detected. Structural characterization of the toxin was performed by a combination of mass spectrometric and nuclear magnetic resonance spectroscopic techniques. A highly purified glycolipid, 2-O-alpha-L-rhamnopyranosyl-alpha-L-rhamnopyranosyl-beta-hydroxytetradec anoyl-beta-hydroxytetradecanoate (Rha-Rha-C14-C14), with a molecular mass of 762 Da was identified. The purified exolipid showed a time- and dose-dependent cytotoxic effect on phagocytic (HL60) and nonphagocytic (HeLa) cell lines. In addition, a time- and dose-dependent hemolysis of erythrocytes from various species was observed. The toxin structure makes a detergentlike action most probable. Interestingly, the cytotoxic and hemolytic activities of the glycolipid could be neutralized by albumin. Future studies will concentrate on the role of this exolipid as a virulence factor in the pathogenesis of melioidosis.

Structure of an acidic exopolysaccharide of Burkholderia pseudomallei

A recently described water-soluble exopolysaccharide of Burkholderia pseudomallei recognized by the IgG 1 monoclonal antibody 3015 [Steinmetz, I., Rohde, M. & Brenneke, B. (1995) Infect. Immun. 63, 3959-3965] was isolated by repetitive ethanol-precipitation steps and by anion-exchange chromatography. The structure of the polysaccharide was determined by a combination of chemical-derivatization and mass-spectrometric techniques (compositional and methylation analysis, GC/MS, and electrospray-ionization-MS/MS of reduced and permethylated hydrolytic fragments), and two-dimensional 1H-NMR methods (COSY, TOCSY and NOESY) and confirmed by isolation and structural characterization of the depolymerized repeating unit of the polysaccharide. The combined structural data established a linear tetrasaccharide repeating unit consisting of three galactose residues, one bearing a 2-linked O-acetyl group, and a 3-deoxy-D-manno-2-octulosonic acid residue. [-->3)-beta-D-Galp2Ac-(1-->4)-alpha-D-Galp-(1-->3)-beta-D-Galp-(1- ->5)-beta-Kdo-(2-->]n

Monoclonal IgA class-switch variants against bacterial surface antigens: molecular forms and transport into murine respiratory secretions

The present study describes a new model for passive immunization of the respiratory tract with IgA in comparison to other isotypes. Monoclonal IgA-isotype-switch variants were isolated from different IgG-producing hybridoma clones specific for surface epitopes of bacterial respiratory tract pathogens. Analysis of the molecular form of the IgA variants revealed the simultaneous production of monomeric, dimeric and higher polymeric IgA by a single-cell line with predominance of the polymeric forms. The specificities of the IgA variants were identical to the parent IgG antibodies as demonstrated by inhibition experiments. The IgA variant antibodies were separated into monomers and polymers by gel filtration. Intravenous injection of the different molecular forms of IgA and of IgG into mice were used to investigate the transport characteristics of IgA into murine upper and lower respiratory tract secretions by the physiological route in comparison to IgG. Polymeric IgA variant, monomeric IgA variant and IgG were detected in immunologically active form in both nasal secretion and bronchoalveolar fluid as evidenced by binding to their antigens in an enzyme-linked immunosorbent assay. The relative contribution of the specific exogenous monoclonal IgA and monoclonal IgG to total IgA and IgG, respectively, was determined in secretions. Comparison of the secretion to serum transport ratios clearly indicates selective transport of polymeric IgA variant into nasal secretions relative to IgG parent antibody. Molecular and functional characteristics of the IgA variants make them ideal for passive mucosal immunization experiments and identification of protective epitopes in mucosal immunity.

[Naturopathy as a contribution to cost control. Attempt at a cost analysis]

OBJECTIVE

A data analysis has been performed to investigate to what extent naturopathy may contribute to reducing costs of medical care.

METHODS

The study included anonymous data from the second quarter of 1988 obtained from the North-Württemberg Kassenärztlichen Vereinigung (insurance company). Physicians practicing in this area at that time were compared to a similarly large collective of those designated additionally as naturopaths and/or homeopaths.

RESULTS

Differences between the two groups were significant with respect to drug costs and disability certificates however not with respect to physician fees.

[Efficiency of homeopathic preparation combinations in sinusitis. Results of a randomized double blind study with general practitioners]

In a controlled randomized double-blind trial carried out by 47 physicians in private practice with totally 152 patients with sinusitis the therapeutic success of the following homeopathic drug preparations was investigated: Group A: combination of luffa operculata D4, kalium bicromicum D4 and cinnabaris D3. Group B: combination of kalium bicromicum D4 and cinnabaris D3. Group C: luffa operculata D4. Group D: placebo. Criteria for the therapeutic result were headache, blocked nasal breathing, trigeminal tenderness, reddening and swelling of nasal mucosa and postnasal secretion. There was no remarkable difference in the therapeutic success among the investigated homeopathic drug combinations nor between the active drugs and placebo. Averaged over all four groups 81% of the patients with acute sinusitis and 67% of the patients with chronic sinusitis recovered. In the literature comparable therapeutic results are reported for antibiotic therapy, decongestant nose drops and for the drainage of nasal cavities.

[Work incapacity within the scope of rehabilitation]

The concept of incapacity for work has been defined by a number of court decision. These have, also, considerably widened the originally narrow concept of disease as the cause of incapacity for work, to cover for example hospital diagnostic procedures, elimination of a congenital defect in view of health improvement or prevention of adverse psychic sequelae, addiction, mental disorders, and so on. In cases of step-wise return to working, the incapable-to-work status continues to apply, as in the event of an unsuccessful trial to resume working. When an illness occurs during participation in a retraining programme, incapacity for work is not determined in terms of the former occupation but in the context of the demands posed by the vocational retraining being attended.

[Pollinosis therapy with Galphimia glauca]

Until now the therapy of pollinosis with Galphimia glauca was based on individual experience. We performed a randomized, controlled, multicenter, and double-blind clinical trial to verify the effectiveness of the Galphimia glauca D4 therapy of patients with pollinosis. The average time of observation was 51/2 weeks. Galphimia was found to be more effective than placebo at a 1% level of significance. Therapeutic success was given in 34/41 (= 83%) of the patients with Galphimia and in 21/45 (= 47%) of the control patients.