Antibiotic Eradication Research Articles

An analysis of totally implantable central venous port system infections in an urban tertiary referral center

A frequent complication of central venous port systems (CVP) is infection (CVP-I), either local (CVP-LI) or a life-threatening blood stream infection (CVP-BSI). We examined the course of CVP-I including results of an antibiotic eradication attempt of CVP-BSI. We investigated adults with CVP-I from 2010 to 2018 who had to undergo port explantation or were treated by a combination of systemic antibiotics and antibiotic lock therapy (ALT). In nine years we diagnosed 206 CVP-I (CVP-LI: 52; CVP-BSI: 152). In 146 patients with CVP-I the port system was primary explanted, while 56 patients received antibiotics/ALT. 79% of Gram negative pathogens and 50% of coagulase negative staphylococci (CoNS) were eradicated. Failure of antibiotic treatment was more often associated with short time span since CVP implantation, neutropenia and polymicrobial infection. All patients with non-neoplastic disease survived, while 18/173 patients (10%) with underlying malignant disease had a fatal outcome in the same hospital stay.

Intravenous versus oral antibiotics for eradication of Pseudomonas aeruginosa in cystic fibrosis (TORPEDO-CF): a randomised controlled trial

SummaryBackgroundChronic pulmonary infection with Pseudomonas aeruginosa is one of the most important causes of mortality and morbidity in cystic fibrosis. If antibiotics are commenced promptly, infection can be eradicated. The aim of the trial was to compare the effectiveness and safety of intravenous ceftazidime and tobramycin versus oral ciprofloxacin in the eradication of P aeruginosa.MethodsWe did a multicentre, parallel group, open-label, randomised controlled trial in 72 cystic fibrosis centres (70 in the UK and two in Italy). Eligible participants were older than 28 days with an isolate of P aeruginosa (either the first ever isolate or a new isolate after at least 1 year free of infection). Participants were excluded if the P aeruginosa was resistant to, or they had a contraindication to, one or more of the trial antibiotics; if they were already receiving P aeruginosa suppressive therapy; if they had received any P aeruginosa eradication therapy within the previous 9 months; or if they were pregnant or breastfeeding. We used web-based randomisation to assign patients to 14 days intravenous ceftazidime and tobramycin or 12 weeks oral ciprofloxacin. Both were combined with 12 weeks inhaled colistimethate sodium. Randomisation lists were generated by a statistician, who had no involvement in the trial, using a computer-generated list. Randomisation was stratified by centre and because of the nature of the interventions, blinding was not possible. Our primary outcome was eradication of P aeruginosa at 3 months and remaining free of infection to 15 months. Primary analysis used intention to treat (powered for superiority). Safety analysis included patients who received at least one dose of study drug. TORPEDO-CF was registered on the ISRCTN register, ISRCTN02734162, and EudraCT, 2009-012575-10.FindingsBetween Oct 5, 2010, and Jan 27, 2017, 286 patients were randomly assigned to treatment: 137 to intravenous antibiotics and 149 to oral antibiotics. 55 (44%) of 125 participants in the intravenous group and 68 (52%) of 130 participants in the oral group achieved the primary outcome. Participants randomly assigned to the intravenous group were less likely to achieve the primary outcome, although the difference between groups was not statistically significant (relative risk 0·84, 95% CI 0·65–1·09; p=0·18). 11 serious adverse events occurred in ten (8%) of 126 participants in the intravenous antibiotics group and 17 serious adverse events in 12 (8%) of 146 participants in the oral antibiotics group.InterpretationCompared with oral therapy, intravenous antibiotics did not achieve sustained eradication of P aeruginosa in a greater proportion of patients with cystic fibrosis and was more expensive. Although there were fewer hospitalisations in the intravenous group than the oral group during follow-up, this confers no advantage over oral treatment because intravenous eradication frequently requires hospitalisation. These results do not support the use of intravenous antibiotics to eradicate P aeruginosa in cystic fibrosis.FundingNational Institute for Health Research Health Technology Assessment Programme.

Is mucosa-associated lymphoid tissue lymphoma an infectious disease? Role of Helicobacter pylori and eradication antibiotic therapy (Review).

Mucosa-associated lymphoid tissue lymphoma (MALT) is seldom considered a diagnosis hypothesis in symptomatic patients. These lymphomas present as a main risk factor for chronic gastritis due to Helicobacter pylori infection. H. pylori leads to chronic inflammation, producing lymphoid tissue in the stomach mucosa (MALT) possibly leading to malignant transformation. Even though H. pylori remains one of the most important factors in the development of MALT lymphoma, it is not mandatory in the evolution of MALT lymphoma since high-grade lymphomas present a lower prevalence of H. pylori. The prevalence of H. pylori is indirectly proportional with the progression into the gastric wall. Mucosal and submucosal MALT lymphomas have a higher prevalence of the bacteria. However, genetic factors remain a risk factor especially if eradication treatment fails. Even though a low percentage of MALT lymphomas are H. pylori-negative, some respond to antibiotic eradication treatment. This can be explained either by the immunomodulatory effect of antibiotics or by other infectious sources such as Helicobacter heilmannii and Campylobacter jejuni (small bowel lymphoma). Treatment in MALT gastric lymphoma was a breakthrough since it was the first time in oncology where tumours were cured by antibiotic therapy, leading us to wonder if MALT lymphomas are infectious disease or not?

Pseudomonas aeruginosa Strain-sharing in Early Infection Among Children With Cystic Fibrosis.

We previously identified Pseudomonas aeruginosa isolates with characteristics typical of chronic infection in some early infections in children with cystic fibrosis (CF), suggesting that these isolates may have been acquired from other patients. Our objective was to define the extent of P. aeruginosa strain-sharing in early CF infections and its impact on antibiotic eradication treatment failure rates. We performed whole genome sequencing on isolates from early pediatric CF pulmonary infections and from the following comparator groups in the same hospital: chronic CF infection, sink drains, sterile site infections, and asymptomatic carriage. Univariate logistic regression was used to assess factors associated with treatment failure. In this retrospective, observational study, 1029 isolates were sequenced. The CF clones strain B and clone C were present. In 70 CF patients with early infections, 14 shared strains infected 29 (41%) patients over 5 years; 16% (n = 14) of infections had mixed strains. In the 70 children, approximately one-third of shared-strain infections were likely due to patient-to-patient transmission. Mixed-strain infections were associated with strain-sharing (odds ratio, 8.50; 95% confidence interval, 2.2-33.4; P = .002). Strain-sharing was not associated with antibiotic eradication treatment failure; however, nosocomial strain transmission was associated with establishment of chronic infection in a CF sibling pair. Although early P. aeruginosa CF infection is thought to reflect acquisition of diverse strains from community reservoirs, we identified frequent early CF strain-sharing that was associated with the presence of mixed strains and instances of possible patient-to-patient transmission.

Helicobacter pylori antibiotic eradication coupled with a chemically defined diet in INS-GAS mice triggers dysbiosis and vitamin K deficiency resulting in gastric hemorrhage

ABSTRACT Infection with Helicobacter pylori causes chronic inflammation and is a risk factor for gastric cancer. Antibiotic treatment or increased dietary folate prevents gastric carcinogenesis in male INS-GAS mice. To determine potential synergistic effects, H. pylori-infected male INS-GAS mice were fed an amino acid defined (AAD) diet with increased folate and were treated with antibiotics after 18 weeks of H. pylori infection. Antibiotic therapy decreased gastric pathology, but dietary folate had no effect. However, the combination of antibiotics and the AAD diet induced anemia, gastric hemorrhage, and mortality. Clinical presentation suggested hypovitaminosis K potentially caused by dietary deficiency and dysbiosis. Based on current dietary guidelines, the AAD diet was deficient in vitamin K. Phylloquinone administered subcutaneously and via a reformulated diet led to clinical improvement with no subsequent mortalities and increased hepatic vitamin K levels. We characterized the microbiome and menaquinone profiles of antibiotic-treated and antibiotic-free mice. Antibiotic treatment decreased the abundance of menaquinone producers within orders Bacteroidales and Verrucomicrobiales. PICRUSt predicted decreases in canonical menaquinone biosynthesis genes, menA and menD. Reduction of menA from Akkermansia muciniphila, Bacteroides uniformis, and Muribaculum intestinale were confirmed in antibiotic-treated mice. The fecal menaquinone profile of antibiotic-treated mice had reduced MK5 and MK6 and increased MK7 and MK11 compared to antibiotic-free mice. Loss of menaquinone-producing microbes due to antibiotics altered the enteric production of vitamin K. This study highlights the role of diet and the microbiome in maintaining vitamin K homeostasis.

2669 Mucosa-Associated Lymphoid Tissue Lymphoma: Crossing the Borders!

INTRODUCTION: Mucosa-associated lymphoid tissue (MALT) lymphoma or MALTomas are responsible for half of the primary gastric lymphomas and up to 8% of B-cell lymphomas. It mostly affects patients in their 5th or 6th decade of life. MALT lymphoma is well known to remain localized in the stomach and to follow a benign course. Despite that gastric MALToma is well defined in the literature, it is rather uncommon to present as a peri-pancreatic mass. Herein, we present the case of a patient with an incidental peri-pancreatic mass diagnosed as an aggressive form of MALT lymphoma. CASE DESCRIPTION/METHODS: A 76-year-old male with hypertension presented to the gastroenterology clinic for the evaluation of peri-pancreatic mass incidentally found during computed tomography (CT) scan performed for renal colic. Physical examination was remarkable for an epigastric fullness with no tenderness. Laboratory tests were remarkable for iron deficiency anemia. CT showed a 7 cm ill-defined soft tissue mass within the pancreaticoduodenal groove abutting the pancreatic head and encasing the gastroduodenal artery suspicious for a pancreatic neoplasm (Figure 1). Endoscopic ultrasound (EUS) showed a hypoechoic heterogeneous mass arising from the gastric wall in close proximity to the pancreas (Figure 2). EUS-guided biopsies were consistent with extra-nodal marginal zone lymphoma of MALT (Figure 3). Gastric biopsies confirmed the presence of MALToma and revealed positive Helicobacter Pylori (HP) infection. Staging workup confirmed extensive bone marrow as well as para-aortic, mediastinal and paratracheal lymph node involvement. The patient received curative HP treatment and was started on bendamustine and rituximab. DISCUSSION: The stomach is the most commonly affected organ by MALT lymphoma. Helicobacter Pylori is a major precursor for the development of gastric MALT lymphoma as up to 90% of affected patients show H.Pylori on stomach biopsies. Chronic HP infection leads to lymphoid tissue proliferation within the stomach and progression towards lymphoma. In this setting, the course is usually indolent with the disease usually confined to the stomach but aggressive tumor behavior has been reported. HP antibiotic eradication remains the first line therapy for early-stage HP positive gastric MALT lymphoma. In other instances, a patient-tailored approach is recommended based on the stage, involved site, HP status and clinical characteristics. Therapeutic options include radiation therapy, chemotherapy and surgery accordingly.

Online registry for nationwide database of Helicobacter pylori eradication in Korea: Correlation of antibiotic use density with eradication success.

BackgroundThe Helicobacter pylori eradication rate has decreased with increasing antibiotic resistance. We conducted a prospective, nationwide, multicenter registry study to monitor the real status of H. pylori eradication therapy and to investigate the association between eradication success and antibiotic use density in Korea.Materials and MethodsWe enrolled 9318 patients undergoing H. pylori eradication therapy from 37 hospitals through “on‐line database registry” from October 2010 to July 2015. Demographic data, detection methods, treatment indications, regimens, durations, compliance, adverse events, and eradication results were collected. The use of all commercially available eradication antibiotics was analyzed through the Korean National Health Insurance data of the Health Insurance Review and Assessment Service. The defined daily dose of antibiotics was used to standardize drug use comparisons.ResultsFinally, 6738 patients were analyzed. The overall eradication rate of first‐line therapy was 71.8%. The eradication success rates were 71.7%, 86.9%, and 74.0% for standard triple therapy for 7 days, quadruple therapy, and concomitant therapy, respectively. The eradication success rate in naive patients was higher than that in those who previously underwent H. pylori eradication. Eradication success was significantly associated with younger age, female sex, and high compliance. Regional differences in eradication rates were observed. The yearly use density of clarithromycin increased statistically in seven regions across the country from 2010 to 2015. The yearly use density of amoxicillin in the Gyeongsang and Chungcheong areas was significantly increased (P < .01), whereas that of other macrolides was significantly lower in the Gyeonggi area than in other areas (P = .01). The overall use of eradication antibiotics has increased while the eradication rate steadily decreased for 5 years. However, there was no significant correlation between antibiotic use density and eradication.ConclusionThere was no relationship between the eradication rate and antibiotic use density in Korea.

Panton-Valentine Leukocidin (PVL) Skin Abscesses in Children and Adolescents Diagnostic and Treatment - A Case Report

Panton–Valentine leukocidin is a cytotoxin, which is associated with an increased virulence of isolates of Staphylococcus aurous. It can cause necrotic dermal lesions or recurrent skin abscesses and in rare cases necrotic haemorrhagic pneumonia. In our case a 15-year-old immunocompetent male was seen in the emergency department complaining of a painful tibial swelling. He had been travelling to South East Asia a year ago and had been suffering from multiple skin abscesses since then. Clinically, a tibial abscess was diagnosed and operatively excised the same day. The postoperative course of the patients was uneventful. In the microbiological analysis a methicillin-susceptible Staphylococcus aurous was isolated and the presence of lukF-lukS genes for Panton–Valentine leukocidin was determined. In order to avoid further spread of the cytotoxin the patient underwent an ambulant antibiotic eradication therapy with Cotrimoxazole 960mg twice daily for 5 days along with a decolonisation. An infection with Panton–Valentine leukocidin should be suspected diagnosed and treated in young immunocompetent patients with recurrent cutaneous abscesses or affected contacts.

Protocol for a controlled human infection with genetically modified Neisseria lactamica expressing the meningococcal vaccine antigen NadA: a potent new technique for experimental medicine

IntroductionNeisseria lactamica is a commensal organism found in the human nasopharynx and is closely related to the pathogen N. meningitidis (meningococcus). Carriage of N. lactamica is associated with reduced meningococcal...

2391. Liposomal Vancomycin and Cefazolin Combinations for S. aureus Biofilms

BackgroundBiofilms are sophisticated communities of matrix-encased and surface-attached bacteria that exhibit a distinct and specific resistant/tolerant phenotype to almost all antibacterial agents, with activity reduced 10- to 1,000-fold. Interestingly, this augmented resistance rapidly reverts when bacteria detach from the biofilm and return to a planktonic state. However, in this in vitro pharmacokinetic and pharmacodynamic (PK/PD) model we are able to expose biofilms to shear rates that are consistent with human interface and mimic antibiotic penetration and diffusion pathways from serum antibiotic concentration in humans.MethodsMethicillin-susceptible ATCC 29213 and MRSA 494 strains were evaluated. Initial susceptibility tests were performed by broth microdilution method. Time kill studies were performed to identify synergy patterns for liposomal and commercial antibiotics. Biofilm eradication was investigated using antibiotics vancomycin (VAN) (commercial) vs. liposomal VAN (VAN-L) (Patent#17-1460) and also combination of VAN- cefazolin (commercial) vs. liposomal vancomycin and liposomal cefazolin (CFZ-L) (Patent# 17-1460) in biofilms for strain MRSA 494. Biofilms were generated overnight using the BioFlux Microfluidic system (Fluxion BioSciences) at constant and continuous shear rates to optimize biofilm attachment and creation. Perfusion of antibiotic solutions (free peak concentration) was applied over a 24 h time period. Time lapse pictures were recorded to determine antibiotic biofilm eradication rates over 18h of incubation and pictures were analyzed using Bioflux Montage software.ResultsMIC values demonstrated a 2-fold reduction for liposomal vancomycin vs. commercial vancomycin. Also, combination of liposomal VAN MIC in presence of CFZ-L showed a 15.87-fold reduction in comparison to commercial VAN for 494. Overall, our biofilm results demonstrated a 43.6% improved eradication using VAN-L and CFZ-L combination in comparison to commercial VAN-CFZ combination. We also observed 5.7% improved eradication using VAN-L vs. commercial VAN.ConclusionLiposomal form of VAN and CFZ combinations are a promising approach to improved efficacy and reduced VAN resistance in S. aureus biofilms.Disclosures M. J. Rybak, Allergan: Consultant, Grant Investigator and Speaker’s Bureau, Research grant and Research support. Achaogen: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Bayer: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Melinta: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Merck: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Theravance: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Sunovian: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. Zavante: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support. NIAID: Consultant, Grant Investigator and Speaker’s Bureau, Consulting fee, Research grant and Research support.

UV light assisted antibiotics for eradication of in vitro biofilms

The overuse of antibiotics is accelerating the bacterial resistance, and therefore there is a need to reduce the amount of antibiotics used for treatment. Here, we demonstrate in vitro that specific wavelengths in a narrow range around 296 nm are able to eradicate bacteria in the biofilm state (grown for 24 hours) more effectively, than antibiotics and the combination of irradiation and antibiotics is even better, introducing a novel concept light assisted antibiotics. The investigated wavelength range was 249 nm to 338 nm with an approximate step of 5 nm. The novel concept that consists of a UV irradiation treatment followed by a tobramycin treatment can significantly reduce the amount of antibiotics needed for eradicating mature bacterial biofilms. The efficiency of the proposed light assisted antibiotics method was compared to combinatory antibiotic treatment and highly concentrated antibiotic monotherapy. The eradication efficacies, on mature biofilms, achieved by light assisted antibiotic and by the antibiotic monotherapy at approximately 10-fold higher concentration, were equivalent. The present achievement could motivate the development of light assisted antibiotic treatments for treating infections.

Factors affecting clinical outcomes in the management of melioidosis in Singapore: a 16-year case series

BackgroundBurkholderia pseudomallei is a gram negative bacteria that causes a spectrum of human diseases in the tropics. Although melioidosis is endemic in Southeast Asia, large clinical case series were rarely reported from metropolitan Singapore.MethodsThis is a retrospective study of 219 consecutive patients with culture proven infections due to Burkholderia pseudomallei between the years 2001 to 2016 managed in Singapore General Hospital (SGH). We aimed to review local patients’ characteristics and identify clinical factors associated with mortality and recurrent melioidosis.ResultsCulture proven melioidosis occurred in 219 patients, 83.1% were male with a mean age of 55.7 ± 14.3 years and 63.0% had diabetes mellitus. Most patients (71.7%) present within 4 weeks of symptom onset and the most common symptom was fever. The majority of patients had bacteremia (67.6%) and had infection involving the respiratory system (71.2%), presenting most frequently with multi-lobar pneumonia. Thirty-four (15.5%) deaths occurred during the initial hospitalisation with a median time from presentation to death of 6.0 days (interquartile range: 2.8–16.3). Twelve patients demised before the diagnosis of melioidosis was made. Univariate analysis identified patients with symptom duration of longer than 4 weeks, bacteremia, and disease requiring mechanical ventilation, inotropic support or temporary dialysis as factors that were significantly associated with mortality. Having bacteremia and disease requiring mechanical ventilation remained statistically significant factors in the multivariable analysis. Twenty-one (11.4%) patients developed at least 1 episode of culture proven recurrent infection, with 15 recurring within the first 12 months of their initial infection. Eight patients developed more than 1 episode of culture proven recurrent infection. Patients with multifocal infection were more likely to develop recurrent infection.ConclusionIn metropolitan Singapore, melioidosis was associated with mortality in excess of 15%, where more than a third occurred before diagnosis. This study reminds local physicians that melioidosis is still a serious infection affecting local male diabetic patients and an important differential diagnosis in a patient presenting with severe multi-lobar pneumonia and septic shock. Recurrent infections occurred in 11.4% and the weight-based dosing of oral eradication antibiotics may improve the management of this disease locally.

Microbiota dysbiosis and its pathophysiological significance in bowel obstruction

Bowel obstruction (OB) causes local and systemic dysfunctions. Here we investigated whether obstruction leads to alterations in microbiota community composition and total abundance, and if so whether these changes contribute to dysfunctions in OB. Partial colon obstruction was maintained in rats for 7 days. The mid colon and its intraluminal feces - proximal to the obstruction - were studied. OB did not cause bacterial overgrowth or mucosa inflammation, but induced profound changes in fecal microbiota composition and diversity. At the phylum level, the 16S rRNA sequencing showed a significant decrease in the relative abundance of Firmicutes with corresponding increases in Proteobacteria and Bacteroidetes in OB compared with sham controls. Daily treatment using broad spectrum antibiotics dramatically reduced total bacterial abundance, but increased the relative presence of Proteobacteria. Antibiotics eliminated viable bacteria in the spleen and liver, but not in the mesentery lymph node in OB. Although antibiotic treatment decreased muscle contractility in sham rats, it had little effect on OB-associated suppression of muscle contractility or inflammatory changes in the muscle layer. In conclusion, obstruction leads to marked dysbiosis in the colon. Antibiotic eradication of microbiota had limited effects on obstruction-associated changes in inflammation, motility, or bacterial translocation.

The Probiotic Lactobacillus rhamnosus for Alleviation of Helicobacter pylori-Associated Gastric Pathology in East Africa.

The probiotic Lactobacillus rhamnosus GG (LGG) can play a role in establishing a harmless relationship with Helicobacter pylori and reduce gastric pathology in East African populations. H. pylori has the ability to inhabit the surface of the mucous layer of the human stomach and duodenum. In the developing world, an estimated 51% of the population is carrier of H. pylori, while in some Western countries these numbers dropped below 20%, which is probably associated with improved sanitation and smaller family sizes. Colonization by H. pylori can be followed by inflammation of the gastric mucus layer, and is a risk factor in the development of atrophic gastritis, peptic ulcers and gastric cancer. Notwithstanding the higher prevalence of H. pylori carriers in developing countries, no equal overall increase in gastric pathology is found. This has been attributed to a less pro-inflammatory immune response to H. pylori in African compared to Caucasian populations. In addition, a relatively low exposure to other risk factors in certain African populations may play a role, including the use of non-steroidal anti-inflammatory drugs, smoking, and diets without certain protective factors. A novel approach to the reduction of H. pylori associated gastric pathology is found in the administration of the probiotic bacterium Lactobacillus rhamnosus yoba 2012 (LRY), the generic variant of LGG. This gastro-intestinal isolate inhibits H. pylori by competition for substrate and binding sites as well as production of antimicrobial compounds such as lactic acid. In addition, it attenuates the host’s H. pylori-induced apoptosis and inflammation responses and stimulates angiogenesis in the gastric and duodenal epithelium. The probiotic LRY is not able to eradicate H. pylori completely, but its co-supplementation in antibiotic eradication therapy has been shown to relieve side effects of this therapy. In Uganda, unlike other African countries, gastric pathology is relatively common, presumably resulting from the lack of dietary protective factors in the traditional diet. Supplementation with LRY through local production of probiotic yogurt, could be a solution to establish a harmless relationship with H. pylori and reduce gastric pathology and subsequent eradication therapy treatment.

Establishing the diagnosis of chronic colonization with Pseudomonas aeruginosa of cystic fibrosis patients: Comparison of the European consensus criteria with genotyping of P. aeruginosa isolates

After antibiotic eradication treatment for a first ever Pseudomonas aeruginosa isolation, the European consensus criteria (ECC) are widely used to assess colonization status with P. aeruginosa in CF-patients. We evaluated to what extent genotyping (GT) of subsequent P. aeruginosa isolates could predict/assess chronic colonization (CC), in comparison with the ECC. MethodsOver a 14-year period, sputa were cultured from 80 CF-patients (age range: 2–51 years), from a first ever isolation of P. aeruginosa onwards. Patients with a positive culture for P. aeruginosa received antibiotic eradication treatment. For the 40 patients for whom three or more P. aeruginosa isolates were available, these isolates were genotyped. ResultsAccording to the ECC, 27 out of the 40 patients (67.5%) became CC during the study period (ECC-positive patients). Genotyping confirmed persistence of the same genotype for 25 of these ECC-positive patients. Genotyping indicated persistence of the same genotype for at least two subsequent isolates for 5 out of 13 ECC-negative patients.Culture-positivity characteristics of the 27 ECC-positive patients corresponded well to those of the 30 GT-positive patients, with an overall higher number of positive cultures as well as a shorter interval in between first and second isolate compared to ECC-negative and GT-negative patients. Genotyping indicated persistence of the same genotype on average 9.3 months earlier than CC according to the ECC (P < 0.01). ConclusionsGenotyping of P. aeruginosa isolates confirmed CC for 25 out of 27 ECC-positive patients (92.6% specificity) and predicted CC 9.3 months earlier than the ECC.

Pyogenic brain abscess caused by Serratia marcescens in a Brazilian premature neonate

Bacterial brain abscess remain a serious central nervous system infectious disorder despite advances in neurosurgical, neuroimaging, clinical support on intensive care units, microbiological techniques and availability of new antibiotics. The successful treatment of brain abscess usually requires surgery, appropriate antibiotic therapy and eradication of the primary source. Although uncommon, brain abscesses are particularly important in the pediatric population due to its devastating potential to cause severe neurologic deficits, especially in preterm newborns. The purpose of the present report is to describe the case of a Brazilian premature neonate with pyogenic brain abscesses caused by Serratia marcescens and to discuss therapeutic and diagnostic approaches. The early suspicion, proper diagnostic measures and immediate neurosurgical consultation associated with aggressive antibiotic therapy seem to be the essentials steps on themanagement for those high-risk pediatric patients.

Early detection using qPCR of Pseudomonas aeruginosa infection in children with cystic fibrosis undergoing eradication treatment

BackgroundInfection with Pseudomonas aeruginosa (Pa) with a chronic phenotype is associated with antibiotic eradication therapy (AET) failure. Our objective was to determine whether higher levels of Pa (detected using qPCR) prior to culture positivity were associated with AET failure in pediatric CF patients. MethodsPa-specific qPCR was performed on stored sputa prior to culture positivity in pediatric CF patients with new-onset culture-positive Pa infections undergoing AET with a 28-day course of tobramycin-inhaled solution (TIS). DNA concentrations were compared in patients in whom AET was successful (Eradicated) to those with persistently positive sputum cultures (Persistent). ResultsForty-seven patients were included. AET was successful in 32 cases (68%), but failed in 15 cases (32%). Median sputum Pa-specific DNA concentration preceding the positive sputum culture was 2.2 × 10−6 μg/mL in Eradicated cases compared to 3 × 10−5 μg/mL in Persistent cases (p = 0.14). There was no significant difference in DNA concentration in the last sputum sample prior to culture positivity, nor in maximal DNA values. There was also no difference in sputum Pa DNA concentrations in patients who had a mucoid (compared to non-mucoid) Pa infection. ConclusionsPediatric CF patients with new-onset Pa infections have detectable Pa-specific DNA in the year preceding a positive culture, however, there is no significant difference in Pa DNA concentrations between patients in whom AET is successful compared to those in whom it fails. Therefore, early molecular detection of Pa may not lead to improved eradication success rates.

One time quantitative PCR detection of Pseudomonas aeruginosa to discriminate intermittent from chronic infection in cystic fibrosis

BackgroundChronic airway infection with Pseudomonas aeruginosa is a major risk factor of progression of lung disease in patients with cystic fibrosis (CF). Chronic P. aeruginosa infection evolves from intermittent infection that is amenable to antibiotic eradication, whereas chronically adapted P. aeruginosa becomes resistant to antibiotic therapy. Discrimination of intermittent versus chronic infection is therefore of high therapeutic relevance, yet the available diagnostic methods are only partly satisfactory. The aim of the present study was, therefore, to evaluate the usage of quantitative PCR (qPCR) to measure pathogen abundance and to discriminate between intermittent and chronic Pseudomonas infection in patients with CF. MethodUsing an established qPCR protocol, we analyzed the abundance of P. aeruginosa in 141 throats swabs and 238 sputa from CF patients with intermittent or chronic infection with P. aeruginosa, as determined by standard culture based diagnostics. ResultsWe observed a large increase of abundance of P. aeruginosa in throat swabs and sputum samples from patients with chronic compared to intermittent infections with P. aeruginosa. The data show that abundance of P. aeruginosa as measured by qPCR is a valuable tool to discriminate intermittent from chronic infection. Of note, P. aeruginosa burden seems more sensitive than mucoidity phenotype to discriminate chronic from intermittent strains. Furthermore we observed that molecular detection in throat swabs was linked to a viable culture in the sputum when sputum was available. This result is of special interest in young patients with cystic fibrosis that often cannot expectorate sputum. We also observed that qPCR in comparison to culture detected the infection earlier. ConclusionThe results suggest that qPCR detection and quantification of P. aeruginosa is a precious tool to be added to the diagnostic toolbox in cystic fibrosis.

Specific mutations of penicillin-binding protein 1A in 77 clinically acquired amoxicillin-resistant Helicobacter pylori strains in comparison with 77 amoxicillin-susceptible strains.

Amoxicillin (Amx) is one of the most important antibiotics for eradication of Helicobacter pylori (H.pylori). Main determinants of genetically stable Amx resistance are mutations in the C-terminus of penicillin-binding protein 1A (pbp1A). However, contribution of individual mutation remains unclear. 77 Amx-resistant (AmxR ) and 77 Amx-susceptible (AmxS ) H.pylori strains were isolated from gastric tissues, and DNA sequencing was performed to compare C-terminus sequences of pbp1A gene between AmxR and AmxS strains. Natural transformation of these mutated genes into amoxicillin-susceptible strains was performed. Among many mutations in pbp1A, D479E (OR: 37.4, 95% CI: 5.53-252.49, P<.001), and T593 mutation (OR: 32.0, 95% CI: 4.04-252.86, P<.001) independently contributed to Amx resistance in H.pylori strains. In the transformation experiment, T593 mutations were identified in their transformants showing Amx resistance. However, PCR product of D479E was not inserted into recipient (ATCC 43504) resulting in transformation failure. Amx resistance is associated with various substitutions in pbp1A and T593 mutation contributes to Amx resistance of H.pylori.

Propionibacterium acnes overabundance and natural killer group 2 member D system activation in corpus-dominant lymphocytic gastritis.

Corpus‐dominant lymphocytic gastritis (LyG) is characterized by CD8 + T‐cell infiltration of the stomach epithelium by a so far uncharacterized mechanism. Although Helicobacter pylori is typically undetectable in LyG, patients respond to H. pylori antibiotic eradication therapy, suggesting a non‐H. pylori microbial trigger for the disease. Comparative microbiota analysis of specimens from LyG, H. pylori gastritis and healthy controls precluded involvement of H. pylori in LyG but identified Propionibacterium acnes as a possible disease trigger. In addition, the natural killer group 2 member D (NKG2D) system and the proinflammatory cytokine interleukin (IL)‐15 are significantly upregulated in the gastric mucosa of LyG patients, and gastric epithelial cells respond to microbe‐derived stimuli, including live P. acnes and the microbial products short‐chain fatty acids, with induction of NKG2D ligands. In contrast, H. pylori infection does not activate or even repress NKG2D ligands. Together, our findings identify P. acnes as a possible causative agent for LyG, which is dependent on the NKG2D system and IL‐15 activation. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.