Effect of dose and timing of prostaglandin F2α treatments during a 7-d Ovsynch protocol on progesterone concentration at the end of the protocol and pregnancy outcomes in lactating Holstein cows.

The objective of this study was to evaluate the effect of two prostaglandin F2α (PGF) treatments 24 h apart (500 µg of cloprostenol) and treatment with a double PGF dose on d 7 (1000 µg of cloprostenol) during a 7-d Ovsynch protocol on progesterone (P4) concentration and pregnancy per artificial insemination (P/AI) in lactating Holstein cows. We hypothesized that treatment leads to a decreased P4 concentration at the second GnRH treatment (G2) and an increase in P/AI compared to the traditional 7-d Ovsynch protocol. A secondary hypothesis was that the treatment effect is influenced by the presence of a corpus luteum (CL) at the first GnRH treatment (G1). Two experiments were conducted on 8 commercial dairy farms in Germany. Once a week, cows from both experiments were assigned in a consecutive manner to receive: (1) Ovsynch (control: GnRH; 7 d, PGF; 9 d, GnRH), (2) Ovsynch with a double PGF dose (GDPG: GnRH; 7 d, 2xPGF; 9 d, GnRH), or (3) Ovsynch with a second PGF treatment 24 h later (GPPG: GnRH; 7 d, PGF; 8 d, PGF; 32 h, GnRH). All cows received timed AI (TAI) approximately 16 h after G2. Pregnancy diagnosis was performed by transrectal palpation (38 ± 3 d after TAI, experiment 1) or transrectal ultrasonography (35 ± 7 d after TAI, experiment 2). Whereas farms from experiment 1 used a Presynch-Ovsynch protocol (PGF, 14 d later PGF, 12 d later GnRH, 7 d later PGF, 2 d later GnRH, and 16-18 h later TAI) to facilitate first postpartum TAI, no presynchronization protocol was used on farms from experiment 2. In experiment 1, we enrolled 1581 lactating dairy cows (60 experimental units) from 2 dairy farms. At G2, blood samples were collected from a subsample of cows (n = 491; 16 experimental units) to determine P4 concentration at G2. In experiment 2, we enrolled 1979 lactating dairy cows (252 experimental units) from 6 dairy farms. Transrectal ultrasonography was performed to determine the presence or absence of a CL at G1. In experiment 1, treatment affected P/AI (P = 0.01) and P/AI was greater for GDPG (38.2%) and GPPG (38.9%) than for control cows (29.8%). Both, GDPG and GPPG cows had decreased P4 concentration at G2 compared with control cows (P < 0.01). Whereas both treatments increased the percentage of cows with very low P4 concentration (0.00-0.09 ng/mL) at G2, only the GPPG treatment decreased the percentage of cows with high P4 concentration (≥0.6 ng/mL) at G2 compared to the control group. In experiment 2, P/AI was greater for GPPG (37.4%) than for control cows (31.0%; P = 0.03) and tended to be greater than for GDPG cows (31.8%; P = 0.05). Cows from the GDPG group had similar (P = 0.77) P/AI compared to the control group. Pregnancy per AI did not differ between cows with a CL at G1 and cows without a CL at G1 (34.1% vs. 32.6%; P = 0.50). There was no interaction between treatment and presence of a CL at G1 on P/AI (P = 0.61). Combining data from the 2 experiments but excluding cows from experiment 1 receiving presynchronization before first TAI (n = 2573; 312 experimental units), P/AI was greater for GPPG (40.3%; P < 0.01) than for control (31.8%) and GDPG cows (33.4%). Between GDPG and control cows, P/AI did not differ (P = 0.46). We conclude that overall the addition of a second PGF treatment on d 8 during a 7-d Ovsynch protocol increased P/AI compared to the traditional 7-d Ovsynch including a single PGF dose on d 7 and to a double PGF dose on d 7. Doubling the PGF dose on d 7 in a 7-d Ovsynch protocol did not affect P/AI. Use of a presynchronization protocol, however, seems to influence the effect of a dose frequency modification of PGF treatment in an Ovsynch protocol. Presynchronized cows receiving first postpartum TAI had similarly increased P/AI treated with a double PGF dose compared with treatment with a second PGF dose. Future studies need to elucidate whether the treatment effect is modified by presynchronization of the first postpartum TAI.

Is there a risk for bacterial transmission from surgical marker pens?

Markers for preoperative skin marking are used several times and bear a risk of transmitting bacteria. Bacterial contamination was assessed by sonication and culture. Antimicrobial susceptibility testing (AST) was performed for facultative pathogens to assess multi-drug resistance (MDR). An accelerated failure time model was applied to assess the statistical relationship between the bacterial contamination and the filling status of markers. Of 45 markers, 13 had a colony count <10 cfu/mL and 32 had counts from 10 to 12,500 cfu/mL. Three markers were colonized by Staphylococcus aureus. No MDR bacteria were found. We recommend single use of markers to reduce transmission risk.

Lack of sensitivity of an IVD/CE-labelled kit targeting the S gene for detection of SARS-CoV-2.

OBJECTIVES: New molecular tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are being rapidly launched in response to the coronavirus disease 2019 (COVID-19) pandemic. The aim of this study was to evaluate the analytical and clinical performance of the VIASURE SARS-CoV-2 S gene RT-PCR Kit on the BD Max™ system and to compare results with those obtained with the cobas® SARS-CoV-2 test on the cobas® 6800 system. METHODS: For testing the analytical performance, reference material was used. Clinical samples (n = 101) obtained from individuals with symptoms compatible with COVID-19 were studied. Oropharyngeal and nasopharyngeal swabs were collected by using either ESwab™ or UTM™ collection systems. RESULTS: When the analytical performance was evaluated, the sample containing the lowest SARS-CoV-2 concentration tested negative with the VIASURE test whereas results obtained with the cobas® test were found to be concordant with the results expected. Six out of the 101 clinical samples (5.9%) showed an inhibition with the VIASURE test. When analysing the remaining 95 clinical samples, 27 were found to be negative with both assays. Of 68 samples that were positive with the cobas® test, the VIASURE test missed 21 (30.9 %) samples. All of those 21 samples had shown Ct values ≥ 31 with the cobas® 6800 system. None of the samples tested positive with the VIASURE test and negative with the cobas® test. CONCLUSIONS: The VIASURE test was impaired by a lack of sensitivity and a relatively high number of invalid results. When using the VIASURE test for routine testing, a significant number of COVID-19-positive samples would have been missed.

Pathogen-specific antibody profiles in patients with severe systemic infections.

Infections are often caused by pathobionts, endogenous bacteria that belong to the microbiota. Trauma and surgical intervention can allow bacteria to overcome host defences, ultimately leading to sepsis if left untreated. One of the main defence strategies of the immune system is the production of highly specific antibodies. In the present proof-of-concept study, plasma antibodies against 9 major pathogens were measured in sepsis patients, as an example of severe systemic infections. The binding of plasma antibodies to bacterial extracellular proteins was quantified using a semi-automated immunoblot assay. Comparison of the pathogen-specific antibody levels before and after infection showed an increase in plasma IgG in 20 out of 37 tested patients. This host-directed approach extended the results of pathogen-oriented microbiological and PCR diagnostics: a specific antibody response to additional bacteria was frequently observed, indicating unrecognised poly-microbial invasion. This might explain some cases of failed, seemingly targeted antibiotic treatment.

A simple laboratory algorithm for diagnosis of melioidosis in resource-constrained areas: a study from north-central Vietnam.

OBJECTIVES: Melioidosis may be endemic in many tropical developing countries, but diagnosis of the disease is currently unreliable in resource-limited areas. We aimed to validate a simple and cheap laboratory algorithm for the identification of Burkholderia pseudomallei from clinical specimens in parts of Vietnam where the disease has not previously been reported. METHODS: In June 2015, we conducted training courses at five general hospitals in north-central provinces in order to raise awareness of the disease and to introduce a simple and cheap laboratory identification algorithm for B. pseudomallei including the three-antibiotic disc test. RESULTS: Until the end of the year (7 months later), 94 suspected B. pseudomallei strains resistant to gentamicin and colistin but sensitive to amoxicillin/clavulanic acid were detected in clinical specimens from 70 patients. All strains were further confirmed as B. pseudomallei by using a specific TTSS1 real-time PCR assay and recA sequencing analysis. Among positive blood cultures, positive rates with B. pseudomallei ranged from 3.4% (5/147) to 10.2% (32/312) in the various clinics. A total of 82.8% (58/70) patients were bacteraemic, with a mortality of 50% (18/36) among patients with known outcome. No death occurred in nonbacteraemic patients. CONCLUSIONS: Our results demonstrate that the introduction of a simple and easy-to-perform laboratory algorithm for the identification of B. pseudomallei from clinical samples, together with clinical awareness raising, can lead to the diagnosis of a significant number of melioidosis cases in resource-limited clinical laboratories which previously did not identify the pathogen.

Monitoring of abdominal Staphylococcus aureus infection using magnetic resonance imaging: a murine animal model for hepatic and renal abscesses.

To establish a routine workflow for in vivo magnetic resonance imaging (MRI) of mice infected with bacterial biosafety level 2 pathogens and to generate a mouse model for systemic infection with Staphylococcus aureus suitable for monitoring by MRI. A self-contained acrylic glass animal bed complying with biosafety level 2 requirements was constructed. After intravenous infection with 105 colony-forming units (CFU) (n = 3), 106 CFU (n = 11) or 107 CFU (n = 6) of S. aureus strain Newman, female Balb/c mice were whole-body scanned by 7T MRI. Abdominal infections such as abscesses were visualized using a standard T2-weighted scan. Infection monitoring was performed for each animal by measurements at 1, 3, and 7 days after infection. Intravenous pathogen application led to a dose-dependent decrease in survival probability (p = 0.03). In the group with the highest infectious dose the 7-day survival rate was 33 %. An intermediate S. aureus dose showed a survival rate of 80 %, whereas at the lowest infection dose, none of the animals died. All animals with the highest infection dose exhibited hepatic abscesses 4 days after inoculation, 80 % developed renal abscesses on the 3rd day. Mice obtaining the intermediate S. aureus load reached a plateau at day 4 with 72 % liver and 60 % renal abscess probability. No abscesses were observed in other abdominal organs at any time point. The implemented experimental setup provides a suitable and reliable in vivo MRI method to study murine abdominal infection models using BSL-2 pathogen. Systemic Staphylococcus aureus infection leads to a dose-dependent development of hepatic and renal abscesses.

[Surveillance reports on pathogens and their antibiotic resistance patterns - a recommendation for standardization]. / Surveillanceberichte zu Erregern und Antibiotikaresistenzen - eine Empfehlung zur Standardisierung.

Surveillance reports on infectious agents and their antibiotic resistance patterns as well as on the usage of antibiotics are now enforced by law for many medical institutions in Germany. However, specific practice-oriented recommendations concerning the appropriate extent and informative mode of presentation are lacking. This consensus statement resulted from the experience from five German university hospitals in handling data from infection epidemiology and in the various possibilities for the presentation of surveillance reports. The consensus statement provides recommendations for the preparation of the legally demanded surveillance reports, extending the existing regulations. The relevance of statements on frequency and quality of microbiological tests is included. Furthermore, modes for the standardization of the data analysis are suggested in order to achieve a regional and national comparability of the results on a high quality level, similarly to the established standardized surveillance of nosocomial infections. This consensus statement describes the form in which the legally enforced reports can be presented in an informative and standardized way in order to facilitate the deduction and realization of preventive measurements.

High prevalence of extended-spectrum-ß-lactamase-producing Enterobacteriaceae in organic and conventional retail chicken meat, Germany.

OBJECTIVES: To determine the prevalence of extended-spectrum ß-lactamase (ESBL) production in Enterobacteriaceae in retail chicken meat in Germany. METHODS: A total of 399 chicken meat samples from nine supermarket chains, four organic food stores and one butcher's shop in two geographically distinct regions (Berlin and Greifswald) were screened for ESBL production using selective agar. Phenotypic ESBL isolates were tested for bla(TEM), bla(CTX-M) and bla(SHV) genes using PCR and DNA sequencing. Antibiotic coresistances were determined and strain typing was performed using PCR-based phylogenetic grouping and XbaI-PFGE. RESULTS: A total of 185 confirmed ESBL isolates were obtained from 175 samples (43.9%) from all tested sources. The majority of isolates were Escherichia coli producing ESBL types SHV-12 (n = 82), CTX-M-1 (n = 77) and TEM-52 (n = 16). No differences could be observed in the prevalence of ESBL producers between organic and conventional samples. 73.0% of the ESBL producers showed coresistance to tetracycline, 35.7% to co-trimoxazole and 7.6% to ciprofloxacin. Strain typing of selected E. coli isolates from Berlin revealed identical macrorestriction patterns for several isolates from samples taken from the same stores. CONCLUSIONS: This is the first comprehensive study from Germany showing a high prevalence of TEM-, CTX-M- and SHV-type ESBLs in Enterobacteriaceae isolated from retail chicken meat. The high rate of coresistance to different classes of antibiotics in the ESBL producers might reflect the common veterinary usage of these and related substances. There is an urgent need to further evaluate the role of poultry in the transmission of highly resistant ESBL-producing bacteria in humans.

Clonal distribution of superantigen genes in clinical Staphylococcus aureus isolates.

Staphylococcus aureus is both a successful human commensal and a major pathogen. The elucidation of the molecular determinants of virulence, in particular assessment of the contributions of the genetic background versus those of mobile genetic elements (MGEs), has proved difficult in this variable species. To address this, we simultaneously determined the genetic backgrounds (spa typing) and the distributions of all 19 known superantigens and the exfoliative toxins A and D (multiplex PCR) as markers for MGEs. Methicillin- sensitive S. aureus strains from Pomerania, 107 nasal and 88 blood culture isolates, were investigated. All superantigen-encoding MGEs were linked more or less tightly to the genetic background. Thus, each S. aureus clonal complex was characterized by a typical repertoire of superantigen and exfoliative toxin genes. However, within each S. aureus clonal complex and even within the same spa type, virulence gene profiles varied remarkably. Therefore, virulence genes of nasal and blood culture isolates were separately compared in each clonal complex. The results indicated a role in infection for the MGE harboring the exfoliative toxin D gene. In contrast, there was no association of superantigen genes with bloodstream invasion. In summary, we show here that the simultaneous assessment of virulence gene profiles and the genetic background increases the discriminatory power of genetic investigations into the mechanisms of S. aureus pathogenesis.

Bacterial colonisation of interior implant threads with and without sealing.

Premature loss of dental implants is due, apart from mechanical factors, to germrelated inflammation. Gaps and hollow spaces within the implant system, for example the gap between implant and abutment in the two-part implant system, may provide a bacterial reservoir causing or maintaining inflammation. The bacterial spectrum involved is similar to that found in periodontitis. This in vitro study aimed to scrutinise the capability of Porphyromonas gingivalis (DSM 20709), the bacterium blamed for inducing peri-implantitis, to pass the implant/abutment gap in titanium implant systems used for orthodontic anchorage and to remain vital in the interior. Additionally, the in vitro effectiveness of gutta percha for gap sealing was examined. Twelve titanium implants (Straumann, diameter: 3.3 mm, length 5.5 mm) were provided with abutments at a defined torque (20 Ncm), six of which were sealed with gutta percha before screwing in the abutment. Subsequently the implants were placed in a nutrient solution (thioglycolate boullion with haemin-menadione solution) that contained Porphyromonas gingivalis. Microbiological specimens were sampled from the implant interiors after 24 and 72 hours and analysed using culture methods. There was evidence that penetration of the periodontal pathogen Porphyromonas gingivalis to the implant interior may occur as early as after 24 hours. Microbes were also detected in the interior of implants sealed with gutta percha. The abutment/implant interface in vitro provides a microbiological leakage for the prospective peri-implantitis-inducing bacterium Porphyromonas gingivalis. Survival of the bacterium is possible in the interior, so that development of a bacterial reservoir is assumed. This in vitro trial produced no evidence that sealing with gutta percha is an effective means to prevent secondary bacterial colonisation in the implant interior.

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.

Residual cftr expression varies with age in cftr(tm1Hgu) cystic fibrosis mice: impact on morphology and physiology.

Mouse models for cystic fibrosis (CF) mimic intestinal manifestations of the human disease, but the lung disease phenotypes are lacking in most strains. In this work, the issue was addressed whether aging of the respiratory tract leads to lung pathophysiology in the exon 10 insertional mutant cftr(tm1Hgu) mouse. Weight gain, body weight and life-span of cftr(tm1Hgu) mice were significantly reduced compared with control mice. cftr(tm1Hgu) mice expressed 20, 21 or 37% (median) of wild-type cystic fibrosis conductance transmembrane regulator (cftr) mRNA transcript in lungs, intestine and kidney. Wild-type cftr mRNA in renal and respiratory epithelia varied with age from levels similar to Ztm:MF1 controls at the age of 2 and 4 months to levels seen in patients with CFTR splice mutations beyond the age of 6 months. The morphology of the bronchi and more distal airways was apparently normal in cftr(tm1Hgu) mice during their first year of life. The alveolar surfactant phospholipid pool was increased in cftr(tm1Hgu) mice by 1.5- to 2-fold compared with Ztm:MF1 controls. Alveolar clearance of gamma-labelled scandium oxide - the first report of lung clearance measurement in living mice - was reduced in cftr(tm1Hgu) mice compared with littermate controls. Although no progressive lung pathology was seen in the cftr expression of cftr(tm1Hgu) mice, surfactant phospholipid homeostasis, and alveolar and mucociliary clearance were abnormal. Therefore, the described model is useful for studying the initial CF lung pathophysiology.

Chronic melioidosis in a patient with cystic fibrosis.

Burkholderia pseudomallei, the causative agent of melioidosis, is endemic in Southeast Asia and northern Australia, where it can be found in soil and surface water. We report a case of chronic pulmonary melioidosis in a patient with cystic fibrosis who had traveled to an area where B. pseudomallei is endemic.

Economic and clinical outcomes of microlaparoscopic and standard laparoscopic sterilization. A comparison.

OBJECTIVE: To compare micro-laparoscopic surgical sterilization and standard laparoscopic sterilization with respect to cost effectiveness and patient preferences. STUDY DESIGN: A retrospective study of all laparoscopic surgical sterilizations performed under general anesthesia at Johns Hopkins Bayview Medical Center--16 micro-laparoscopies and 34 standard laparoscopies. Cases selected for review were limited to patients undergoing surgical contraception and not requiring additional, concurrent procedures. Laparoscopic surgical sterilization was performed using a double-puncture technique with silicone band application. In each case either a standard, 10-mm laparoscope or a 2-mm micro-laparoscope was used, and the procedure was performed under general anesthesia. Postoperative pain management was achieved by nonsteroidal antiinflammatory drugs and/or narcotic analgesia. All cases were performed by residents under faculty supervision. Medical records and hospital billing records were reviewed, and a standardized telephone interview was conducted to assess postoperative quality of life and patient satisfaction. RESULTS: Both techniques were comparable in cost effectiveness. There was no significant difference in operating room time, average operating room costs, average ancillary department costs, instrument and supply costs, or length of stay. Postoperative discomfort was significantly less with microlaparoscopy (P = .05), and patient satisfaction was higher in the microlaparoscopy group. CONCLUSION: Microlaparoscopy and the standard laparoscopic approach for surgical sterilization are associated with similar hospital charges. Postoperative pain and overall patient satisfaction were significantly better with microlaparoscopy than standard laparoscopy.

Discordancy between clinical predictions vs lymphoscintigraphic and intraoperative mapping of sentinel lymph node drainage of primary melanoma.

OBJECTIVE: To evaluate discordancy between clinical predictions and lymphatic drainage patterns of primary cutaneous melanoma as determined by preoperative lymphoscintigraphy and intraoperative lymphatic mapping of sentinel lymph nodes (SLNs). DESIGN: Before selective SLN dissection, 226 consecutive patients with melanoma underwent preoperative lymphoscintigraphy. SETTING: Teaching hospital tertiary care center. MAIN OUTCOME MEASURE: Correlation of lymphatic drainage patterns from the following 3 data sources: clinical predictions preoperatively based on anatomical location of primary melanoma, lymphatic drainage patterns as determined by preoperative lymphoscintigraphy, and identification of SLNs during surgery. RESULTS: Preoperative lymphoscintigraphy was successful in identifying at least 1 SLN in all 226 patients. In head and neck melanomas, at least 1 SLN was identified in an area outside what would have been clinically predicted in 11 (36.7%) of 30 cases. Discordancy for trunk melanomas was seen in 24 (25.3%) of 95 cases. Extremity melanomas showed drainage to unexpected SLNs in 6 (13.6%) of 44 and 3 (5.3%) of 57 patients for the upper and lower extremities, respectively. The overall rate of discordancy was 44 (19.5%) of 226. The SLNs were identified in surgery in all but 4 cases. CONCLUSIONS: Discordancy is most frequent in melanomas of the head and neck region, followed by that of the trunk. Preoperative lymphoscintigraphy identifies the occasional cases in the upper and lower extremities where drainage occurs to a basin that is not clinically predictable. Preoperative lymphoscintigraphy is a prerequisite for characterizing the lymphatic drainage pattern in patients with primary melanoma, especially for sites such as head and neck as well as trunk, before selective SLN dissection.

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.

Rapid identification of Burkholderia pseudomallei by latex agglutination based on an exopolysaccharide-specific monoclonal antibody.

We recently identified a constitutively expressed exopolysaccharide of Burkholderia pseudomallei which is composed of a unique linear tetrasaccharide repeating unit consisting of three galactose residues and one 3-deoxy-D-manno-2-octulosonic acid residue. In this study we developed a latex agglutination test based on monoclonal antibody 3015, which is specific for this exopolysaccharide, and evaluated this test for rapid identification of B. pseudomallei grown on agar plates. All 74 environmental and clinical B. pseudomallei strains tested, originating from different areas of Southeast Asia, northern Australia, and Africa, showed a strong and specific agglutination. B. pseudomallei-like organisms and a variety of other bacteria did not react. In conclusion this monoclonal antibody-based test is a simple, rapid, and highly specific method for identifying B. pseudomallei culture isolates from different geographic areas.