Exopolysaccharides produced by clinical strains belonging to the Burkholderia cepacia complex

BackgroundIn the frame of a research line dedicated to better clarify the role of exopolysaccharides (EPS) in bacterial virulence, EPS produced by species of the Burkholderia cepacia complex (Bcc), namely Burkholderia multivorans, Burkholderia cenocepacia, and a Bcc member of undetermined genomovar, all isolated at the Cystic Fibrosis Regional Centre of Florence (Italy), were investigated for they structural properties.MethodsThree strains of B. multivorans, three of B. cenocepacia and one of a Bcc member of undetermined genomovar were isolated from CF patients. The reference strains C1576 and J2315, for genomovar II and III, respectively, were included in the study. The bacteria were grown on solid media, the exopolysaccharides produced were purified, and their structures were determined. In addition, sugar analysis of sputum samples was accomplished to search for EPS produced in vivo.ResultsSix strains out of seven produced the exopolysaccharide cepacian, while one strain of B. multivorans produced a completely different polymer, previously known in the literature as PS1. Two strains synthesised very small amounts of EPS. No definitive evidence for the presence of cepacian in sputum samples was found.ConclusionsMost strains examined produced abundant amounts of polysaccharides. Cepacian was the most common EPS isolated and its production was not associated to a particular genomovar.     

Various Aspects of Bacterial Infections in the Early Postoperative Stage Among Lung Transplant Recipients on Broad-Spectrum Antibiotics: A Single Center Study

BackgroundLife-long immunosuppression after lung transplantation increases the risk of bacterial infections, hence broad-spectrum antibiotics can be implemented after transplant. The aim of this study is to assess various aspects of bacterial infections in the early postoperative stage among lung transplant recipients on broad-spectrum antibiotics at a single center.MethodsThis retrospective study consists of 134 primary lung transplant recipients transplanted between 2014 and 2021 at a single center. Study analyzed the occurrence of de novo bacterium in bronchoalveolar lavage sampled 2 to3 weeks after lung transplantation, as well as survival and the occurrence of bacterial sepsis. Studied antibiotics include linezolid, meropenem, tobramycin, and cloxacillin.ResultsNone of the patients from the broad-spectrum antibiotics developed bacterial sepsis within the first 30 postoperative days. In-hospital mortality due to bacterial sepsis among patients in the broad-spectrum group was 1.89%. The most common new pathogen in first couple of days after lung transplantation was Burkholderia multivorans (42%). After its occurrence, Ceftazidime was administered. It significantly reduced the occurrence of hospital-acquired B multivorans after 2 to 3 weeks post-transplant (χ² = 8.01, P = .005).ConclusionBroad-spectrum antibiotics seem to be an efficient approach against bacterial infections for lung transplant recipients in the early post-transplant period, as patients treated this way very rarely develop fatal bacterial infections in the studied period. Ceftazidime proved efficient for treatment for B multivorans among the studied group. Patients, who acquired new pathogen during post-transplant hospital stay presented comparable lung function at discharge in comparison to those who were not.     

Burkholderia multivorans septicemia in a pediatric liver transplant patient

“Cepacia syndrome”, caused by Burkholderia cepacia complex and often associated with cystic fibrosis, carries a high mortality rate. It is rare for Burkholderia multivorans, a species within the B. cepacia complex, to cause cepacia syndrome even among patients with cystic fibrosis. This is the first reported fatal case of cepacia syndrome caused by B. multivorans occurring in a pediatric liver transplant recipient who does not have cystic fibrosis. We describe the unique characteristics of this pathogen among the non–cystic fibrosis population and the importance of early recognition and treatment.     

Investigating the role of matrix components in protection of Burkholderia cepacia complex biofilms against tobramycin

BackgroundBurkholderia cepacia complex (Bcc) organisms produce a wide variety of potential virulence factors, including exopolysaccharides (EPS), and exhibit intrinsic resistance towards many antibiotics. In the present study we investigated the contribution of Bcc biofilm matrix components, including extracellular DNA, cepacian and poly-β-1,6-N-acetylglucosamine, to tobramycin susceptibility.MethodsThe in vitro bactericidal activity of tobramycin in combination with recombinant human DNase (rhDNase), NaClO and dispersin B was tested against Bcc biofilms.ResultsEPS degradation by NaClO pretreatment and specific PNAG degradation by dispersin B significantly increased the bactericidal effect of tobramycin towards some of the Bcc biofilms tested, including the strains of Burkholderia cenocepacia, B. cepacia and Burkholderia metallica. The presence of rhDNase during biofilm treatment and/or development had no influence on tobramycin activity.ConclusionThese results suggest that EPS play a role in tobramycin susceptibility of Bcc biofilms and that matrix degrading combination therapy could improve treatment of Bcc biofilm infections.     

AR-13 reduces antibiotic-resistant bacterial burden in cystic fibrosis phagocytes and improves cystic fibrosis transmembrane conductance regulator function

BackgroundThere are no effective treatments for Burkholderia cenocepacia in patients with cystic fibrosis (CF) due to bacterial multi-drug resistance and defective host killing. We demonstrated that decreased bacterial killing in CF is caused by reduced macrophage autophagy due to defective cystic fibrosis transmembrane conductance regulator (CFTR) function. AR-12 is a small molecule autophagy inducer that kills intracellular pathogens such as Francisella. We evaluated the efficacy of AR-12 and a new analogue AR-13 in reducing bacterial burden in CF phagocytes.MethodsHuman CF and non-CF peripheral blood monocyte-derived macrophages, neutrophils, and nasal epithelial cells were exposed to CF bacterial strains in conjunction with treatment with antibiotics and/or AR compounds.ResultsAR-13 and not AR-12 had growth inhibition on B. cenocepacia and methicillin-resistantStaphylococcus aureus (MRSA) in media alone. There was a 99% reduction in MRSA in CF macrophages, 71% reduction in Pseudomonas aeruginosa in CF neutrophils, and 70% reduction in non-CF neutrophils using AR-13. Conversely, there was no reduction in B. cenocepacia in infected CF and non-CF macrophages using AR-13 alone, but AR-13 and antibiotics synergistically reduced B. cenocepacia in CF macrophages. AR-13 improved autophagy in CF macrophages and CF patient-derived epithelial cells, and increased CFTR protein expression and channel function in CF epithelial cells.ConclusionsThe novel AR-12 analogue AR-13, in combination with antibiotics, reduced antibiotic-resistant bacterial burden in CF phagocytes, which correlated with increased autophagy and CFTR expression. AR-13 is a novel therapeutic for patients infected with B. cenocepacia and other resistant organisms that lack effective therapies.     

Diversity of β-lactamases produced by imipenem resistant,Pseudomonas aeruginosa isolates from the bloodstream

IntroductionThe emergence of imipenem non-susceptible Pseudomonas aeruginosa isolates is a matter of great concern because these isolates can become resistant to all available antibiotics. This study conducted to characterize β-lactamase genes in imipenem resistant P. aeruginosa isolates from bloodstream.Methods56 non-duplicate clinical isolates of P. aeruginosa were collected in Tehran hospitals. Antibacterial susceptibility was determined by disk diffusion and MIC methods. ESBL and MBL production was confirmed by combined disk. β-Lactamase classes A, B and D genes were identified by PCR.ResultsSeventeen (30.3%) isolates were imipenem resistant for which 16 isolates simultaneously were resistant to all tested antibiotics. While among 39 imipenem susceptible isolates, only two isolates were resistant to all tested antibiotics. In imipenem resistant isolates, bla_TEM, bla_SHV and bla_OXA-10 were found in 41.1% of isolates and bla_VIM, bla_IMP and bla_PER were identified in 47%, 11.7% and 5.8% of isolates respectively, while in imipenem susceptible isolates, bla_TEM, bla_SHV and bla_OXA-10 were determined in 2.5%, 7.6% and 33.3% of isolates, respectively. The imipenem resistant isolates had been recovered mostly (67.7%) from patients in the Burn hospital.ConclusionThe result of this study indicated the emergence of multidrug resistant MBL and non-MBL producing P. aeruginosa, particularly in the Burn hospital and bla_VIM was dominant β-lactamase genes in imipenem resistant isolates. The isolation of carrier patients may lead to prevent a further dissemination.     

Common pathogens in burn wound and changes in their drug sensitivity

Infection is an important cause of mortality in patients with burns. Rapid emergence of hospital pathogens and antibiotic-resistant organisms necessitate periodic evaluation of bacterial colonisation patterns and antibiogram sensitivity in burn wards.In this study, which was conducted in a 3 months’ period in 2009, 106 samples from the wounds of 59 patients admitted in a burn ward were taken, one in the 1st and one between the 3rd and the 7th days.Pseudomonas aeruginosa, Acinetobacter and Klebsiella were the most common Gram-negative and Staphylococcus aureus was the most common Gram-positive organisms recovered from the patients.This study showed a high rate of resistance to the administered antibiotics. The prevalent Gram-negative organisms in our ward were resistant to ceftazidime and imipenem in nearly 90% and 20% of cases, respectively.     

The cystic fibrosis gut as a potential source of multidrug resistant pathogens

BackgroundThe emergence of multidrug resistant (MDR) pathogens represents a profound threat to global health. Individuals with CF have amongst the highest cumulative antibiotic exposure of any patient group, including to critically-important last-line agents. While there is little evidence that antibiotic resistance in airway pathogens results in worse clinical outcomes for CF patients, the potential emergence of MDR pathogens in non-respiratory systems, as a consequence of CF care, represents a potential health threat to the wider population, including family and carers.MethodsStool from 19 adults with CF and 16 healthy adult controls was subjected to metagenomic sequencing, to assess faecal resistome, and culture-based analysis. Resistant isolates were identified phenotypically, and genetic determinants of resistance characterised by whole genome sequencing.ResultsCF and control faecal resistomes differed significantly (P = 0.0003). The proportion of reads that mapped to mobile genetic elements was significantly higher in CF (P = 0.014) and the composition was significantly different (P = 0.0001). Notably, CF patients displayed higher carriage of plasmid-mediated aminoglycoside-modifying genes ant(6)-Ib, aac(6′)-Ip, and aph(3′)-IIIa (P < 0.01). Culture-based analysis supported higher aminoglycoside resistance, with a higher proportion of aminoglycoside-resistant, Gram-negative bacteria (P < 0.0001). Isolated extended spectrum beta lactamase (ESBL)-positive Escherichia coli from CF stool exhibited phenotypic resistance to tobramycin and gentamicin. Genomic analysis showed co-localisation of both aminoglycoside resistance and ESBL genes, consistent with MDR emergence through horizontal gene transfer.ConclusionsThe carriage of potentially transmissible resistance within the adult CF gut microbiome is considerably greater than in healthy individuals and could contribute to the emergence and dissemination of MDR pathogens.     

Disseminated Melioidosis presenting as pneumonia,femoral and sacral osteomyelitis,splenic abscess and high rectal fistula: A case report and review of literature

IntroductionMelioidosis is a rare infectious tropical disease caused by Burkholderia pseudomallei (B. pseudomallei), an environmental saprophyte usually habitating on soils of Southeast Asian fields. Most of the reported cases present with pneumonia and intra-abdominal abscess. Diagnosis is established by culture studies from the blood, sputum or abscess drainage. Management relies on culture-guided antibiotic treatment, with good prognosis. Surgical intervention is required in cases not responsive to medical management.Presentation of caseWe are presenting a case of Melioidosis in a 72 year old Filipino who presented with Pneumonia, Femoral and Sacral Osteomyelitis, Splenic Abscess and High Rectal Fistula. He was successfully managed with systemic antibiotic treatment and surgery. The splenic abscess was managed by splenectomy and a transverse loop colostomy was used for fecal diversion to address the rectal fistula.DiscussionMelioidosis varies in its presentation and thus management should be individualized, depending on the organs involved. Our patient presented with multiple foci of infection which rendered the treatment more complicated as compared to those reported previously in published literature. The pneumonia and the osteomyelitis were managed with aggressive systemic antibiotics but the other sites of infection required drainage and surgery.ConclusionMelioidosis is a rare infection caused by an environmental saprophyte Burkholderia pseudomallei. An accurate diagnosis using culture studies is essential to institute appropriate treatment. Antibiotic treatment complemented by surgery for specific organ involvement is essential for cure.     

Epidemiology and resistance of Achromobacter xylosoxidans from cystic fibrosis patients in Dijon,Burgundy: First French data

BackgroundAchromobacter xylosoxidans is an emerging pathogen in cystic fibrosis (CF) patients recognised as causal agent of inflammation. The prevalence of infection or colonisation is variable among CF centres. We report here the first epidemiological data about A. xylosoxidans in a French CF centre: Dijon, Burgundy.MethodsAll isolates recovered from the patients affiliated with our centre in 2010 since their first visit were included. Antimicrobial susceptibility was determined by disk diffusion method and E-test. Molecular epidemiology was performed by Pulsed Field Gel Electrophoresis (PFGE) and compared with repetitive sequence-based PCR (rep-PCR, DiversiLab®). We also sequenced the constitutive bla-_oxa-114 gene.ResultsOut of 120 patients, 21 (17.5%) had at least one positive culture with A. xylosoxidans since they started to receive routine care in our CF centre (447 isolates). Median age at first positive culture was 16 years (range 3–34 years). Most patients were colonised by their own strain, cross-contamination was very rare. We observed two cases of intra-family spread. DiversiLab® is a useful tool as efficient as PFGE to compare isolates recovered simultaneously from different patients when an outbreak is suspected. However, PFGE remains the reference method for long-term survey of chronically colonised patients. We detected new OXA-114 variants and the new oxacillinase OXA-243 (88% amino acid identity with OXA-114). Acquired resistance to ciprofloxacin, ceftazidime and carbapenems was frequent. In 2010, 7 patients harboured strains resistant to ceftazidime, 6 patients strains with decreased susceptibility to carbapenems (especially meropenem) and 12 patients strains resistant to ciprofloxacin.ConclusionsIn our centre, the high prevalence of colonisation is not due to cross-contamination. Our main concern is the high rate of antimicrobial resistance.     

Cross infection between cystic fibrosis patients colonised with Burkholderia cepacia

Whilst patient to patient spread of the respiratory pathogenBurkholderia cepacia is well recognised between patientswith cystic fibrosis, prompting a strict segregation policy, cross colonisation between cystic fibrosis patients already infected withB cepacia has not been described and surveys show a very low incidence of patients with more than one strain. Five adult cysticfibrosis patients with B cepacia are presented who became cross colonised with a second B cepacia (UK epidemic)strain, four of whom then died, three from the cepacia syndrome. These cases show that, amongst segregated patients, cross colonisation withdifferent B cepacia strains is possible, and even in these patients the acquisition of the UK epidemic strain may have a fataloutcome. In future it may be necessary to segregate cystic fibrosispatients colonised with the UK epidemic strain from all other patientswith cystic fibrosis.

     

Amoxicillin–clavulanic acid resistance in fecal Enterobacteriaceae from patients with cystic fibrosis and healthy siblings

BackgroundThe present study set out to detect and identify amoxicillin–clavulanic acid (AMC)-resistant Enterobacteriaceae in fecal samples of two patients with cystic fibrosis (CF) and their respective siblings.MethodsFecal Enterobacteriaceae were enumerated onto EMB agar containing amoxicillin (AMX). A total of 173 CF isolates and 41 sibling isolates were grouped into seven Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) clusters and identified through 16S rRNA and rpoB sequence analysis.ResultsThe fecal microbiota of patients with CF revealed a higher prevalence of AMX resistant Enterobacteriaceae compared to that of their healthy siblings. Whereas all selected isolates of healthy siblings were assigned to Escherichia coli, isolates of patients with CF belonged to Klebsiella oxytoca (58.4%), E. coli (28.3%), Klebsiella variicola (7.5%) or Citrobacter sp. (5.8%). All tested CF isolates showed a high resistance rate to AMX, and a lower level of resistance to the combination with clavulanic acid. In contrast, all tested sibling isolates were susceptible for both AMX and AMC.ConclusionThe higher abundance of AMX resistance in the investigated patients with CF suggests that frequent AMC administration may be one of the major contributing factors in the proliferation of Enterobacteriaceae and the development of resistant strains in the gastrointestinal tract.     

Predictors of multi-drug resistance in burn wound colonization following burn injury in a resource-limited setting

IntroductionBacterial resistance to antibiotics is growing dramatically worldwide due to several contributing factors, including inappropriate antibiotic utilization in the clinical setting and widespread use in the food production industry. Consequently, it is imperative to characterize antibiotic resistance in high-risk populations, such as burn patients, particularly in resource-limited settings where prevention strategies may be high-yield and new antibiotics are not readily available. We therefore sought to characterize and identify predictors of multi-drug resistant (MDR) bacteria colonization in burn patients at our center in Malawi.MethodsThis is a prospective analysis of burn patients presenting to Kamuzu Central Hospital in Lilongwe, Malawi within 72 h of burn injury. A swab of each patient’s primary wound was collected at admission and each subsequent week. The primary aim was to determine predictors of colonization in burn wounds with multi-drug resistant bacteria using modified Poisson regression modeling.Results99 patients were enrolled and analyzed. The median age was 4 years (IQR 2–12) with a median % total burn surface area (TBSA) of 14% (IQR 9–25). The most common burn injury type was scald (n = 61, 61.6%), followed by flame (n = 37, 37.4%). Overall, 54 patients (54.6%) were colonized with MDR bacteria at some point during their hospitalization, with increases each week. For flame burns, the predictors of MDR bacterial colonization were each 1% increase of %TBSA (RR 1.01, 95% CI 1.00, 1.03, p = 0.038) and the use of operative intervention for burn treatment (RR 1.90, 95% CI 1.17, 3.09, p = 0.010). No variables were predictive of MDR wound colonization in scald burns.ConclusionOur study identified that almost half of the patients in a Malawian burn unit had MDR bacteria colonizing burn wounds after only a week in the hospital. This increased to almost 70% during hospitalization. We also found that for patients with flame burns, increasing %TBSA, and operative intervention put patients at greater risk of MDR colonization. Interventions such as isolation of burn patients, consistent disinfection and sterilization of wards and operating rooms, and optimization of wound care management are imperative to decrease spread of MDR bacteria and to improve burn-associated clinical outcomes in resource-limited environments.     

Early treatment with inhaled antibiotics postpones next occurrence of Achromobacter in cystic fibrosis

ObjectivesIn this nationwide retrospective study, we analysed species distribution, antimicrobial susceptibility and time to next occurrence of Achromobacter in Danish cystic fibrosis (CF) patients from 2000 to 2011.MethodsThirty-four primary isolates were identified to species level and subjected to antimicrobial susceptibility testing. Effectiveness of early antimicrobial treatment was assessed by a Kaplan–Meier estimation of time to recurrence.ResultsAchromobacter xylosoxidans accounted for 13 (38%) of the isolates, and an unnamed species accounted for 11 (32%) of the isolates. Meropenem, piperacillin–tazobactam and trimethoprim–sulfamethoxazole were highly active against chemotherapy-naïve Achromobacter, while ceftazidime, colistin and tobramycin were judged adequate for inhalation therapy. Fifty-five percent of 25 patients treated with inhaled ceftazidime, colistin, or tobramycin remained free of Achromobacter three years after acquisition, in contrast to 17% of 22 patients who did not receive inhaled antibiotics (P < 0.01).ConclusionsEarly treatment with inhaled antibiotics may prevent or postpone chronic infection with Achromobacter in CF patients.     

Persistence of bacterial growth on antibiotic-loaded beads: Is it actually a problem?

Background and purpose?Implantation of antibiotic-loaded beads is used for orthopedic infections. However, recent in vitro reports have emphasized that bacteria can persist on—or even colonize—antibiotic-impregnated bone cement. We therefore assessed whether bacterial adherence and growth could be determined on gentami-cin- and gentamicin-vancomycin-loaded beads that had been removed after eradication of infection.

Material and methods?We bacteriologically examined 18 chains of antibiotic-loaded beads (11 gentami-cin-loaded, 7 gentamicin-vancomycin-loaded) that had been implanted because of orthopedic infections. Among the causative agents, Staphylococcus epidermidis, Staph-ylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) were the most frequent organisms identified.

Results?In 4 cases (3 with S. epidermidis and one with MRSA), we found that there was persistence of bacterial growth on the beads. S. epidermidis strains persisted only on gentamicin-loaded beads, while MRSA could grow on gentamicin-vancomycin-impregnated cement. In one case, the emergence of a gentamicin-resistant S. epidermidis strain was observed despite the fact that preoperative samples of S. epidermidis from this patient had been susceptible to the antibiotic.

Interpretation?Persistence of bacterial growth on bone cement remains a hazardous problem in orthopedic surgery. Adherence of bacteria to cement can lead to emergence of bacterial resistance to antibiotics and might result in clinical recurrence of infection.     

Tolerant Small-colony Variants Form Prior to Resistance Within a Staphylococcus aureus Biofilm Based on Antibiotic Selective Pressure

BackgroundThe treatment of periprosthetic joint infection (PJI) is focused on the surgical or chemical removal of biofilm. Antibiotics in isolation are typically ineffective against PJI. Bacteria survive after antibiotic administration because of antibiotic tolerance, resistance, and persistence that arise in the resident bacteria of a biofilm. Small-colony variants are typically slow-growing bacterial subpopulations that arise after antibiotic exposure and are associated with persistent and chronic infections such as PJI. The role of biofilm-mediated antibiotic tolerance in the emergence of antibiotic resistance remains poorly defined experimentally.Questions/purposesWe asked: (1) Does prior antibiotic exposure affect how Staphylococcus aureus survives within a developing biofilm when exposed to an antibiotic that penetrates biofilm, like rifampicin? (2) Does exposure to an antibiotic with poor biofilm penetration, such as vancomycin, affect how S. aureus survives within a developing biofilm? (3) Do small-colony variants emerge from antibiotic-tolerant or -resistant bacteria in a S. aureus biofilm?MethodsWe used a porous membrane as an in vitro implant model to grow luminescent S. aureus biofilms and simultaneously track microcolony expansion. We evaluated the impact of tolerance on the development of resistance by comparing rifampicin (an antibiotic that penetrates S. aureus biofilm) with vancomycin (an antibiotic that penetrates biofilm poorly). We performed viability counting after membrane dissociation to discriminate among tolerant, resistant, and persistent bacteria. Biofilm quantification and small-colony morphologies were confirmed using scanning electron microscopy. Because of experimental variability induced by the starting bacterial inoculum, relative changes were compared since absolute values may not have been statistically comparable.ResultsAntibiotic-naïve S. aureus placed under the selective pressure of rifampicin initially survived within an emerging biofilm by using tolerance given that biofilm resident cell viability revealed 1.0 x 10⁸ CFU, of which 7.5 x 10⁶ CFU were attributed to the emergence of resistance and 9.3 x 10⁷ CFU of which were attributed to the development of tolerance. Previous exposure of S. aureus to rifampicin obviated tolerance-mediate survival when rifampicin resistance was present, since the number of viable biofilm resident cells (9.5 x 10⁹ CFU) nearly equaled the number of rifampicin-resistant bacteria (1.1 x 10¹⁰ CFU). Bacteria exposed to an antibiotic with poor biofilm penetration, like vancomycin, survive within an emerging biofilm by using tolerance as well because the biofilm resident cell viability for vancomycin-naïve (1.6 x 10¹⁰ CFU) and vancomycin-resistant (1.0 x 10¹⁰ CFU) S. aureus could not be accounted for by emergence of resistance. Adding rifampicin to vancomycin resulted in a nearly 500-fold reduction in vancomycin-tolerant bacteria from 1.5 x 10¹⁰ CFU to 3.3 x 10⁷ CFU. Small-colony variant S. aureus emerged within the tolerant bacterial population within 24 hours of biofilm-penetrating antibiotic administration. Scanning electron microscopy before membrane dissociation confirmed the presence of small, uniform cells with biofilm-related microstructures when unexposed to rifampicin as well as large, misshapen, lysed cells with a small-colony variant morphology [29, 41, 42, 63] and a lack of biofilm-related microstructures when exposed to rifampicin. This visually confirmed the rapid emergence of small-colony variants within the sessile niche of a developing biofilm when exposed to an antibiotic that exerted selective pressure.ConclusionTolerance explains why surgical and nonsurgical modalities that rely on antibiotics to “treat” residual microscopic biofilm may fail over time. The differential emergence of resistance based on biofilm penetration may explain why some suppressive antibiotic therapies that do not penetrate biofilm well may rely on bacterial control while limiting the emergence of resistance. However, this strategy fails to address the tolerant bacterial niche that harbors persistent bacteria with a small-colony variant morphology.Clinical RelevanceOur work establishes biofilm-mediated antibiotic tolerance as a neglected feature of bacterial communities that prevents the effective treatment of PJI.     

Inhaled amiloride and tobramycin solutions fail to eradicate Burkholderia dolosa in patients with cystic fibrosis

BackgroundBurkholderia dolosa can result in chronic airway infection and rapid decline in lung function in patients with cystic fibrosis (CF). Amiloride has antibacterial properties that may be synergistic with aminoglycosides against other species belonging to the Burkholderia cepacia complex (Bcc). We attempted to eradicate B. dolosa using a combination of nebulized tobramycin and nebulized amiloride in infected CF patients.MethodsA 6-month, open-label trial of continuous inhaled amiloride, delivered via nebulization four times daily, and continuous inhaled tobramycin (TIS or TOBI®) nebulized twice daily, was offered to all CF patients at our institution who are chronically infected with B. dolosa.ResultsTwenty two of 27 patients with B. dolosa were eligible and twelve elected to participate. Eradication of B. dolosa was not noted in any study subject. While patients tolerated treatment with no adverse effects, there was also no apparent impact on other secondary outcome measures.ConclusionsConcurrent, continuous inhalation of amiloride and tobramycin for 6 months was not effective for the eradication of chronic B. dolosa airway infection in CF patients.     

Lactobacillus fermentum,a pathogen in documented cholecystitis

INTRODUCTIONLactobacillus species are probiotics proven to exhibit various preventative as well as therapeutic properties. While lactobacillus species have been implicated in the formation of dental caries, endocarditis and bacteremia, their role as pathogens in cholecystitis has not been reported. We present a rare case of Lactobacillus fermentum working as a pathogen in cholecystitis.PRESENTATION OF CASEAn 81-year old male was admitted with right upper quadrant abdominal pain. His signs, symptoms, laboratory values and imaging were consistent with a diagnosis of cholecystitis with ascending cholangitis. In view of his co-morbidity and severe sepsis, the patient was treated non-operatively with antibiotics and cholecystostomy. L. fermentum, which was vancomycin resistant, was identified from the cholecystostomy aspirate and from anaerobic blood culture. The patient went into septic shock, developed multi-organ dysfunction syndrome and eventually died.DISCUSSIONCommensal bacteria such as L. fermentum are known to modulate immunity, reduce the pathogenicity of gastrointestinal organisms and play a therapeutic role in various disease processes. We isolated L. fermentum as a pathogen in a documented case of cholecystitis with ascending cholangitis.CONCLUSIONWhile the routine use lactobacillus species as a probiotic is supported in the literature, understanding its potential role as a pathogen may allow more judicious use of these bacteria and encourage research to elucidate the pathogenicity of lactobacillus species.     

Species distribution of Burkholderia cepacia complex isolates in cystic fibrosis and non-cystic fibrosis patients in New Zealand

Burkholderia cepacia complex (Bcc) isolates from 39 CF patients and 25 non-CF patients in New Zealand were speciated and characterised using the multilocus sequence typing (MLST) scheme for Bcc. B. multivorans predominated in CF patients (31/39, 79.5%) and in non-CF patients (7/25, 28%). Sequence types (ST) with an international distribution were identified (27/64, 42.2%) among the New Zealand Bcc isolates. MLST revealed a high level of diversity among Bcc isolates in CF patients indicating a lack of person-to-person transmission. Non-CF patients showed less diversity in MLST types, however, individuals with shared STs were geographically and chronologically separated. The use of MLST analysis allows continued surveillance of isolates with the potential to identify outbreaks. The identification of internationally distributed strains may provide an indicator of the relative transmissibility and infectivity of these strains and warrants further investigation.