Miquel B. Ekkelenkamp

Bacteremic Complications of Intravascular Catheters Colonized with Staphylococcus aureus

Patients with Staphylococcus aureus colonization of an intravascular catheter but without demonstrated bacteremia within 24 h after intravascular catheter removal had a 24% (12 of 49 patients) chance of subsequent S. aureus bacteremia if they did not receive immediate antistaphylococcal antibiotics. Treatment within 24 h after intravascular catheter removal led to a 83% reduction in the incidence of subsequent bacteremia.

Isolation and structural characterization of epilancin 15X, a novel lantibiotic from a clinical strain of Staphylococcus epidermidis

The potential application of lantibiotics as food‐preserving agents and more recently as antibiotics has strongly increased the interest in these antibacterial peptides. Here, we report the elucidation of the primary and three‐dimensional structures of the novel lantibiotic epilancin 15X from Staphylococcus epidermidis using high‐resolution nuclear magnetic resonance spectroscopy and tandem mass spectrometry. The molecule contains ten post‐translationally modified amino acids, three lanthionine ring structures and a hydroxy‐propionyl N‐terminal moiety. The primary and tertiary structure and the distribution of positive charges are closely similar to the previously identified lantibiotic epilancin K7, most likely indicative of a common mode of action.

Quantifying the Relationship between Staphylococcus aureus Bacteremia and S. aureus Bacteriuria: A Retrospective Analysis in a Tertiary Care Hospital

In this retrospective cohort study, patients who had Staphylococcus aureus bacteremia but who lacked signs and symptoms of urinary tract infection due to S. aureus and who did not have an indwelling urinary catheter had a likelihood of S. aureus bacteriuria of 2.5% (2 of 79 patients). Therefore, we strongly question the theory that S. aureus bacteremia causes S. aureus bacteriuria.

Relationship between bacterial colonization of external cerebrospinal fluid drains and secondary meningitis: a retrospective analysis of an 8-year period

OBJECT A frequent complication of CSF drains is secondary meningitis. This study was designed to assess the predictive value of a positive culture from a CSF drain tip for the development of secondary meningitis. METHODS The authors conducted a retrospective study of an 8-year period in which patients were treated in a tertiary care hospital in The Netherlands. Patients with positive cultures from CSF drain tips were identified from the microbiology database. Patient charts were reviewed to retrieve demographic, clinical, and laboratory data. Statistical analysis was performed using multivariate logistic regression to determine significant risk factors for the development of secondary meningitis. RESULTS A total of 139 patients with positive CSF-drain cultures were included; 72 patients (52%) suffered secondary meningitis at the time of CSF drain removal, or developed it consecutively. Development of secondary meningitis was associated with use of ventricular drains (OR 3.4 vs lumbar drains; 95% CI 1.7-6.8), with age less than 18 years (OR 4.7; 95% CI 1.3-17.3), and with colonization with Staphylococcus aureus (OR 3.1 vs other microorganisms; CI 1.2-8.5). Thirty-two patients (44% of total secondary meningitis) were diagnosed with secondary meningitis 24 hours or more after CSF drain removal; in 13 patients (18%) the diagnosis was made after 48 hours or more. CONCLUSIONS Positive CSF-drain cultures are strongly associated with development of secondary meningitis. A positive CSF-drain culture may precede clinical symptoms and should therefore be communicated to the treating physician by the microbiological laboratory as soon as possible, and prophylactic antibiotic therapy should be considered.

Dual pneumococcal and influenza vaccination: severe concerns about the composition of the control groups.

To the Editor—We have read with interest the article by Hung et al [1] on the effects of dual vaccination with a 23valent pneumococcal vaccine and a trivalent influenza vaccine. The authors observed a difference in the occurrence of pneumonia and cardiovacular incidents between the patients who received both vaccines, the patients who received 1 of the 2 vaccines, and the patients who were not vaccinated. A significant difference in cerebrovascular incidents and in mortality was observed only between the dual vaccinees and the unvaccinated patients. The observational nature of this study, in which patients were free to choose which vaccinations they would receive, makes it prone to selection bias. In previous studies on influenza vaccination, it has been observed that a large and significant part of the difference in the occurrence of medical complications between vaccinated and unvaccinated patients—if not the entire observed effect—is attributable to the difference in health status between the 2 groups: vaccination is associated with a more active lifestyle and a better health status [2]. Although few of the presented baseline characteristics differed significantly between the groups in this study, selection bias cannot be excluded. In this light, it is important to describe the different groups. Hung et al [1] state, in the first paragraph of the Results, that ‘‘25,393 [patients] were unvaccinated. Fifty-five percent of the unvaccinated declined vaccination by choice, whereas the remaining 45% were excluded for other reasons stated in the exclusion criteria.’’ This last sentence is unclear; it suggests that the control group (no vaccination) consisted of 14,000 patients who declined vaccination plus the 11,400 patients who did

Antimicrobial resistance in women with urinary tract infection in primary care : No relation with type 2 diabetes mellitus

AIMS To determine if type 2 diabetes mellitus (T2DM) is associated with the spectrum of uropathogens and antimicrobial resistance in urinary tract infections (UTI) in primary care. METHODS A cross-sectional study in female outpatients ≥30 years with positive urine cultures. T2DM patients were 1:1 matched to controls by age group and general practitioner (GP). GPs were sent questionnaires for additional data. Uropathogens and resistance patterns were compared between patients with and without T2DM. Multivariable regression analysis was performed to assess the independent association between T2DM and resistance to first line treatments, defined as resistance to nitrofurantoin, trimethoprim, fosfomycin, ciprofloxacin, amoxicillin/clavulanic acid and/or trimethoprim/sulfamethoxazole. RESULTS In 566 urine cultures, 680 uropathogens were found. Resistance to first line treatment antibiotics was present in 62.5% of patients. Frequencies and resistance rates of uropathogens did not differ between both groups of patients. Previous UTI and previous hospital admission were independent risk factors for resistance, but T2DM was not. CONCLUSIONS In this study T2DM was not an independent risk factor for antimicrobial resistance in UTI in primary care. Previous UTI and hospitalisation are drivers of resistance and should be included in the decision to perform a urine culture to target first line UTI treatment.

Defining antimicrobial resistance in cystic fibrosis

Antimicrobial resistance (AMR) can present significant challenges in the treatment of cystic fibrosis (CF) lung infections. In CF and other chronic diseases, AMR has a different profile and clinical consequences compared to acute infections and this requires different diagnostic and treatment approaches. This review defines AMR, explains how it occurs, describes the methods used to measure AMR as well as their limitations, and concludes with future directions for research and development in the area of AMR in CF.

Antimicrobial susceptibility of non-fermenting Gram-negative pathogens isolated from cystic fibrosis patients

Non-fermenting Gram-negative bacteria (NFGNB) are increasingly cultured in respiratory samples from cystic fibrosis (CF) patients. This study determined the antimicrobial susceptibility of clinical CF respiratory isolates from distinct geographical regions. A total of 286 isolates (106 Stenotrophomonas maltophilia, 100 Burkholderia spp., 59 Achromobacter spp., 12 Pandoraea spp., 9 Ralstonia spp.) from the Netherlands, Northern Ireland, Spain, USA and Australia were tested. MIC50/90 values and susceptibility categorisation were determined. Trimethoprim/sulfamethoxazole (SXT) was the most active compound for all micro-organisms (MIC50, 0.12-4 mg/L; MIC90, 1-16 mg/L). For S. maltophilia, 47% and 62% of isolates were susceptible to SXT according to CLSI and EUCAST breakpoints, respectively. Ceftazidime presented lower susceptibility (35%; MIC50, 32 mg/L; MIC90, 256 mg/L). MIC90 values for tobramycin and colistin were >128 mg/L and >16 mg/L, respectively. Regarding Burkholderia, 72%, 56% and 44% were susceptible to SXT, ceftazidime and meropenem, respectively. For both ceftazidime and meropenem, MIC50 and MIC90 values were within the intermediate or resistant category. The most active antibiotics for Achromobacter spp. were SXT (MIC50, 0.5 mg/L; MIC90, 8 mg/L) and imipenem (MIC50, 2 mg/L; MIC90, 8 mg/L). SXT, imipenem and ciprofloxacin were active against 12 Pandoraea spp. (MIC50, 0.12-4 mg/L; MIC90, 1-8 mg/L). Ciprofloxacin (MIC50, 4 mg/L) and SXT (MIC50, 1 mg/L) were the only active antibiotics for Ralstonia spp. There were no statistically significant differences in susceptibility rates between countries. NFGNB other than Pseudomonas aeruginosa are potential pathogens in CF. SXT was demonstrated to be the most active compound against these isolates.

Therapy and Outcome of Staphylococcus aureus Infections of Intracorporeal Ventricular Assist Devices: Staphylococcus aureus VAD INFECTIONS

Abstract Infection of the driveline or pump pocket is a common complication in patients with ventricular assist devices (VADs) and Staphylococcus aureus is the main pathogen causing such infections. Limited evidence is currently available to guide the choice of antibiotic therapy and the duration of treatment in these patients. Patients at the University Medical Center Utrecht who developed a VAD‐related S. aureus infection between 2007 and 2016 were retrospectively assessed. Blood culture isolates were typed by whole genome sequencing to differentiate between relapses and reinfections, and to determine whether antibiotic therapy had led to acquisition of resistance mutations. Twenty‐eight patients had S. aureus VAD infections. Ten of these patients also suffered S. aureus bacteremia. Discontinuation of antibiotic therapy was followed by relapse in 50% of the patients without prior S. aureus bacteremia and in 80% of patients with bacteremia. Oral cephalexin could ultimately suppress the infection for the duration of follow‐up in 8/8 patients without S. aureus bacteremia and in 3/6 patients with S. aureus bacteremia. Clindamycin failed as suppressive therapy in 4/4 patients. Cephalexin appears an adequate choice for antibiotic suppression of VAD infections with methicillin‐susceptible S. aureus. In patients without systemic symptoms, it may be justified to attempt to stop therapy after treatment of the acute infection, but antibiotic suppression until heart transplant seems indicated in patients with S. aureus bacteremia.