Alexandra T. Bernards

Extended-Spectrum β-Lactamase–producing Enterobacteriaceae among Travelers from the Netherlands

A prospective cohort study was performed among travelers from the Netherlands to investigate the acquisition of carbapenemase-producing Enterobacteriaceae (CP-E) and extended-spectrum β-lactamase–producing Enterobacteriaceae (ESBL-E) and associated risk factors. Questionnaires were administered and rectal swab samples were collected and tested before and after traveler return. Of 370 travelers, 32 (8.6%) were colonized with ESBL-E before trave,; 113 (30.5%) acquired an ESBL-E during travel, and 26 were still colonized 6 months after return. No CP-E were found. Independent risk factors for ESBL-E acquisition were travel to South and East Asia. Multilocus sequence typing showed extensive genetic diversity among Escherichia coli. Predominant ESBLs were CTX-M enzymes. The acquisition rate, 30.5%, of ESBL-E in travelers from the Netherlands to all destinations studied was high. Active surveillance for ESBL-E and CP-E and contact isolation precautions may be recommended at admission to medical facilities for patients who traveled to Asia during the previous 6 months.

Effects of Decontamination of the Oropharynx and Intestinal Tract on Antibiotic Resistance in ICUs: A Randomized Clinical Trial

IMPORTANCE Selective decontamination of the digestive tract (SDD) and selective oropharyngeal decontamination (SOD) are prophylactic antibiotic regimens used in intensive care units (ICUs) and associated with improved patient outcome. Controversy exists regarding the relative effects of both measures on patient outcome and antibiotic resistance. OBJECTIVE To compare the effects of SDD and SOD, applied as unit-wide interventions, on antibiotic resistance and patient outcome. DESIGN, SETTING, AND PARTICIPANTS Pragmatic, cluster randomized crossover trial comparing 12 months of SOD with 12 months of SDD in 16 Dutch ICUs between August 1, 2009, and February 1, 2013. Patients with an expected length of ICU stay longer than 48 hours were eligible to receive the regimens, and 5881 and 6116 patients were included in the clinical outcome analysis for SOD and SDD, respectively. INTERVENTIONS Intensive care units were randomized to administer either SDD or SOD. MAIN OUTCOMES AND MEASURES Unit-wide prevalence of antibiotic-resistant gram-negative bacteria. Secondary outcomes were day-28 mortality, ICU-acquired bacteremia, and length of ICU stay. RESULTS In point-prevalence surveys, prevalences of antibiotic-resistant gram-negative bacteria in perianal swabs were significantly lower during SDD compared with SOD; for aminoglycoside resistance, average prevalence was 5.6% (95% CI, 4.6%-6.7%) during SDD and 11.8% (95% CI, 10.3%-13.2%) during SOD (P < .001). During both interventions the prevalence of rectal carriage of aminoglycoside-resistant gram-negative bacteria increased 7% per month (95% CI, 1%-13%) during SDD (P = .02) and 4% per month (95% CI, 0%-8%) during SOD (P = .046; P = .40 for difference). Day 28-mortality was 25.4% and 24.1% during SOD and SDD, respectively (adjusted odds ratio, 0.96 [95% CI, 0.88-1.06]; P = .42), and there were no statistically significant differences in other outcome parameters or between surgical and nonsurgical patients. Intensive care unit-acquired bacteremia occurred in 5.9% and 4.6% of the patients during SOD and SDD, respectively (odds ratio, 0.77 [95% CI, 0.65-0.91]; P = .002; number needed to treat, 77). CONCLUSIONS AND RELEVANCE Unit-wide application of SDD and SOD was associated with low levels of antibiotic resistance and no differences in day-28 mortality. Compared with SOD, SDD was associated with lower rectal carriage of antibiotic-resistant gram-negative bacteria and ICU-acquired bacteremia but a more pronounced gradual increase in aminoglycoside-resistant gram-negative bacteria. TRIAL REGISTRATION trialregister.nlIdentifier: NTR1780.

Negative pressure wound treatment with polyvinyl alcohol foam and polyhexanide antiseptic solution instillation in posttraumatic osteomyelitis

In a retrospective, case–control cohort study an assessment was made of the clinical outcome of patients with osteomyelitis treated with a new modality of negative pressure wound therapy, so called negative pressure instillation therapy. In this approach, after surgical debridement, a site of osteomyelitis is treated with negative pressure of at least 300 mmHg applied through polyvinyl alcohol dressing. The polyvinyl alcohol foam is irrigated through the tubes three times a day with a polyhexanide antiseptic solution. In 30 patients (14 males; mean age 52 [range, 26–81]) admitted between 1999 and 2003 with osteomyelitis of the pelvis or lower extremity, we assessed time to wound closure, number of surgical procedures and rate of recurrence of infection as well as need for rehospitalizations. For comparison, a control group of 94 patients (males, 58; mean age 47 [range, 9–85]), matched for site and severity of osteomyelitis, was identified in hospital records between 1982 and 2002. These patients underwent standard surgical debridement, implantation of gentamicin polymethylmethacrylate beads and long‐term intravenous antibiotics. In the Instillation group the rate of recurrence of infection was 3/30 (10%), whereas 55/93 (58.5%) of the controls had a recurrence (p<0.0001). Moreover, in those treated with instillation the total duration of hospital stay was shorter and number of surgical procedures smaller as compared with the controls (all p<0.0001). We conclude that in posttraumatic osteomyelitis negative pressure instillation therapy reduces the need for repeated surgical interventions in comparison with the present standard approach.

Persistent Acinetobacter baumannii? Look inside your medical equipment.

Two outbreaks of multidrug-resistant Acinetobacter baumannii occurred in our hospital. The outbreak strains were eventually isolated from respiratory ventilators, an apparatus used to cool or warm patients, and four continuous veno-venous hemofiltration machines. Removing dust from the machines and replacing all dust filters brought the outbreaks to an end.

Endemic and Epidemic Acinetobacter Species in a University Hospital: an 8-Year Survey

ABSTRACT The prevalence of the currently known Acinetobacter species and related trends of antimicrobial resistance in a Dutch university hospital were studied. Between 1999 and 2006, Acinetobacter isolates from clinical samples were collected prospectively. Isolates were analyzed by amplified fragment length polymorphism fingerprinting. For species identification, a profile similarity cutoff level of 50% was used, and for strain identification, a cutoff level of 90% was used. Susceptibility for antimicrobial agents was tested by disk diffusion by following the CLSI guideline. The incidences of Acinetobacter isolates ranged from 1.7 to 3.7 per 10,000 patients per year, without a trend of increase, during the study years. Twenty different species were distinguished. Acinetobacter baumannii (27%) and Acinetobacter genomic species (gen. sp.) 3 (26%) were the most prevalent. Other species seen relatively frequently were Acinetobacter lwoffii (11%), Acinetobacter ursingii (4%), Acinetobacter johnsonii (4%), and Acinetobacter junii (3%). One large cluster of A. baumannii, involving 31 patients, and 16 smaller clusters of various species, involving in total 39 patients, with at most 5 patients in 1 cluster, occurred. Overall, 37% of the A. baumannii isolates were fully susceptible to the tested antibiotics. There was a borderline significant (P = 0.059) trend of decreasing susceptibility. A. baumannii was the Acinetobacter species causing the largest burden of multiple-antibiotic resistance and transmissions in the hospital.

Do maggots have an influence on bacterial growth? A study on the susceptibility of strains of six different bacterial species to maggots of Lucilia sericata and their excretions/secretions.

PURPOSE The maggots of Lucilia sericata are successfully used as a treatment for infected wounds. Many articles are published about possible direct antibacterial properties of maggots and their excretions/secretions (ES), but with different results. The present study reinvestigates the susceptibility of six bacterial strains to maggots and their ES. METHODS Live maggots were added to a bacterial suspension. After incubation for 16 h, the bacterial growth in this suspension was compared with the growth in a suspension without maggots. We tested Instar-1 and Instar-3 maggots and compared nutrient broths. A turbidimetric assay investigated the antibacterial activity of ES. Finally, we compared the bacterial growth of Gram-positive and Gram-negative bacteria. RESULTS The test with live maggots showed an increase of bacterial growth. Instar-1 maggots stimulated more bacterial growth than Instar-3 maggots, as well as the use of a more nutritious broth. The turbidimetric assay showed no inhibition of bacterial growth. For all bacteria, except Pseudomonas aeruginosa, an increase in bacterial growth was shown. CONCLUSION There is no direct antibacterial effect of maggots and/or ES in vitro, however in clinical observations maggot therapy is successful. More research is needed to focus on possible indirect antibacterial activity, such as an immune-related effect.

Evaluation of Several Biochemical and Molecular Techniques for Identification of Streptococcus pneumoniae and Streptococcus pseudopneumoniae and Their Detection in Respiratory Samples

ABSTRACT The identification and detection of mitis group streptococci, which contain Streptococcus pneumoniae, have been hampered by the lack of sensitive and specific assays. In this study, we evaluated several biochemical and molecular assays for the identification of S. pneumoniae and Streptococcus pseudopneumoniae and their distinction from other mitis group streptococci using a collection of 54 isolates obtained by the routine culturing of 53 respiratory specimens from patients with community-acquired pneumonia. The combined results of the biochemical and molecular assays indicated the presence of 23 S. pneumoniae, 2 S. pseudopneumoniae, and 29 other mitis group streptococcal isolates. The tube bile solubility test that is considered gold standard for the identification of S. pneumoniae showed concordant results with optochin susceptibility testing (CO2 atmosphere) and a real-time multiplex PCR assay targeting the Spn9802 fragment and the autolysin gene. Optochin susceptibility testing upon incubation in an O2 atmosphere, bile solubility testing by oxgall disk, matrix-assisted laser desorption ionization–time of flight mass spectrometry, and sequence analysis of the tuf and rpoB genes resulted in several false-positive, false-negative, or inconclusive results. The S. pseudopneumoniae isolates could be identified only by molecular assays, and the multiplex real-time PCR assay was concluded to be most convenient for the identification of S. pneumoniae and S. pseudopneumoniae isolates. Using this method, S. pneumoniae and S. pseudopneumoniae DNA could be detected in the respiratory samples from which they were isolated and in an additional 11 samples from which only other streptococci were isolated.

An integrated approach to control a prolonged outbreak of multidrug‐resistant Pseudomonas aeruginosa in an intensive care unit

In this paper we aim to provide insight into the complexity of outbreak management in an intensive care unit (ICU) setting. In October 2010 four patients on the ICU of our tertiary care centre were colonized or infected with a multidrug-resistant strain of Pseudomonas aeruginosa (MDR-PA). An outbreak investigation was carried out and infection control measures were taken in an attempt to identify a potential source and stop transmission. The outbreak investigation included descriptive epidemiology, comprising retrospective case finding by reviewing the laboratory information system back to 2004 and prospective case finding by patient screening for MDR-PA. Furthermore, microbiological analysis, environmental screening and a case-control study were carried out. Infection control measures consisted of re-education of healthcare personnel on basic hygiene measures, auditing of hygiene procedures used in daily practice by infection control practitioners, and stepwise up-regulation of isolation measures. From February 2009 to January 2012, 44 patients on our ICU were found to be MDR-PA positive. MDR-PA isolates of the 44 patients showed two distinct AFLP patterns, with homology within each of the AFLP clusters of more than 93%. The VIM metallo-β-lactamase gene was detected in 20 of 21 tested isolates. A descriptive epidemiology investigation identified the rooms with the highest numbers of MDR-PA positive patients. The case-control study showed three factors to be independently associated with MDR-PA positivity: admission to ICU subunit 1 (OR, 6.1; 95% CI, 1.7, 22), surgery prior to or during admission (OR, 5.7; 95% CI, 1.6, 20) and being warmed-up with the warm-air blanket (OR, 3.6; 95% CI, 1.2, 11). After three environmental screening rounds, with sampling of sinks, furniture and devices in the ICU, without revealing a clear common source, a fourth environmental investigation included culturing of faucet aerators. Two faucets were found to be positive for MDR-PA and were replaced. The occurrence of new cases decreased with the strengthening of infection control measures and declined further with the removal of the common source. With this integrated approach a prolonged outbreak of P. aeruginosa was controlled. Contaminated faucet aerators on the ICU probably served as a persisting source, while interpatient transmission by medical staff was a likely way of spread. Seven months after the last case (January 2012) and 3 months after cessation of extended isolation measures (May 2012), single cases started to occur on the ICU, with a total of seven patients in the past year. No common source has yet been found.

Consequences of switching from a fixed 2 : 1 ratio of amoxicillin/clavulanate (CLSI) to a fixed concentration of clavulanate (EUCAST) for susceptibility testing of Escherichia coli

OBJECTIVES The CLSI recommends a fixed 2 : 1 ratio of co-amoxiclav for broth microdilution susceptibility testing of Enterobacteriaceae, while EUCAST recommends a fixed 2 mg/L clavulanate concentration. The aims of this study were: (i) to determine the influence of a switch from CLSI to EUCAST methodology on Escherichia coli susceptibility rates; (ii) to compare susceptibility results obtained using EUCAST-compliant microdilution with those from disc diffusion and the Etest; and (iii) to evaluate the clinical outcome of patients with E. coli sepsis treated with co-amoxiclav in relation to the susceptibility results obtained using either method. METHODS Resistance rates were determined in three laboratories that switched from CLSI to EUCAST cards with the Phoenix system (Becton Dickinson) as well as in 17 laboratories that continued to use CLSI cards with the VITEK 2 system (bioMérieux). In one laboratory, isolates were simultaneously tested by both the Phoenix system and either disc diffusion (n = 471) or the Etest (n = 113). Medical and laboratory records were reviewed for E. coli sepsis patients treated with co-amoxiclav monotherapy. RESULTS Only laboratories that switched methodology showed an increase in resistance rates - from 19% in 2010 to 31% in 2011 (P < 0.0001). All isolates that tested susceptible by microdilution were also susceptible by disc diffusion or the Etest, but of 326 isolates that tested resistant by microdilution, 43% and 59% tested susceptible by disc diffusion and the Etest, respectively. Among the 89 patients included there was a better correlation between clinical response and measured MICs using the Phoenix system than the Etest. CONCLUSIONS EUCAST methodology resulted in higher co-amoxiclav E. coli resistance rates than CLSI methodology, but correlated better with clinical outcome. EUCAST-compliant microdilution and disc diffusion provided discrepant results.

Notice of Retraction and Replacement: Oostdijk et al. Effects of Decontamination of the Oropharynx and Intestinal Tract on Antibiotic Resistance in ICUs: A Randomized Clinical Trial. JAMA. 2014;312(14):1429-1437.

Citation for published version (APA): Oostdijk, E. A. N., Kesecioglu, J., Schultz, M. J., Visser, C. E., de Jonge, E., van Essen, E. H. R., ... Bonten, M. J. M. (2017). Notice of Retraction and Replacement: Oostdijk et al. Effects of Decontamination of the Oropharynx and Intestinal Tract on Antibiotic Resistance in ICUs: A Randomized Clinical Trial. JAMA. 2014;312(14):1429-1437. JAMA Journal of the American Medical Association, 317(15), 15831584. DOI: 10.1001/jama.2017.1282