P40 Kitchen sponges—home sweet home for carbapenem-resistant Klebsiella spp

Background

Although research on foodborne diseases is well documented for certain microorganisms, less research has been undertaken on cross-contamination with Enterobacteriaceae from food within the kitchen environment. In this study, we analysed the presence of Klebsiella spp. and Raoultella spp. and their antibiotic resistance in 100 used kitchen sponges. In a domestic environment, kitchen sponges are commonly used by consumers for doing the dishes and/or cleaning kitchen surfaces. Given their multipurpose use, their often high humidity and presence of organic residuals they are considered a favourable habitat for various groups of microorganisms and could serve as a vehicle in transmission of foodborne pathogens.^1,2

Material and methods

A total of 100 kitchen sponges alongside a questionnaire regarding hygienic parameters were randomly collected from domestic environments and analysed within 24 h after arrival in the lab. Kitchen sponges were immersed in 100 mL buffered peptone water, homogenized and incubated at 37°C for 24 h ± 2 h. Ten microlitres of this enrichment was plated on MacConkey agar (Bio-Rad) and incubated at 37°C for 24 h ± 2 h. Presumptive Klebsiella spp. and Raoultella spp. were isolated and confirmed by MALDI-TOF MS. Antibiotic resistance testing (ART) was performed on all Klebsiella spp. and Raoultella spp. isolates following the EUCAST guidelines. WGS was performed using the Illumina platform.

Results

A total of 65% of the kitchen sponges were positive for Klebsiella spp. or Raoultella spp. The species Klebsiella oxytoca was detected in 78.5% of positive samples, followed by Klebsiella pneumoniae (12.31%), Raoultella ornithinolytica (4.62%), Klebsiella variicola (1.54%), Klebsiella aerogenes (1.54%) and Raoultella planticola (1.54%). To the best of our knowledge this is the first study performed on detection of Klebsiella spp. in kitchen sponges from Belgium and has comparable results with previous studies.^1–3 We hypothesize the high positivity rate is caused by cross-contamination. ART revealed the presence of one carbapenem-resistant isolate, with resistance to ertapenem and meropenem. Reduced susceptibility to carbapenems was caused by the presence of bla_SHV-36 combined with porin deficiency. Klebsiella spp. can be part of the commensal flora of human intestines but are considered to be opportunistic pathogens. Klebsiella spp. might present antimicrobial resistance and carbapenem-resistant Enterobacteriaceae are taken up in the WHO global priority list of antibiotic-resistant bacteria.

Conclusions

High prevalence of Klebsiella spp. and a carbapenem-resistant isolate in kitchen sponges highlight the occurrence of cross-contamination from food and the possible risks for foodborne disease associated with this kitchen tool. These findings advocate for good hygienic measures within a household setting.

Use of next-generation sequencing in microbial risk assessment

Despite the ever increase in rigorous control and monitoring measures to assure safe food along the entire farm‐to‐fork chain, the past decade has also witnessed an increase in microbial food alerts. Hence, research on food safety and quality remain of utmost importance. Complementary, and at least as important, is the necessity to be able to assess the potential microbial risks along the food chain. Risk assessment relies on sound scientific data. Unfortunately, often, quality data are limited if not lacking. High‐throughput tools such as next‐generation sequencing (NGS) could fill this gap. NGS approaches can be used to generate ample qualitative and quantitative data to be used in the risk assessment process. NGS applications are not new in food microbiology with applications ranging from pathogen detection along the food chain, food epidemiology studies, whole genome analysis of food‐associated microorganisms up to describing complete food microbiomes. Yet, its application in the area of microbial risk assessment is still at an early stage and faces important challenges. The possibilities of NGS for risk assessment are ample, but so are the questions on the subject. One of the major strengths of NGS lies in its capacity to generate a lot of data, but to what extend can this wealth be of use in hazard identification, hazard characterisation and exposure assessment to perform a sound risk characterisation, which in turn will make it possible to take substantiated risk management decisions.

Managing pregnancy of unknown location based on initial serum progesterone and serial serum hCG levels: development and validation of a two-step triage protocol

OBJECTIVES

A uniform rationalized management protocol for pregnancies of unknown location (PUL) is lacking. We developed a two-step triage protocol to select PUL at high risk of ectopic pregnancy (EP), based on serum progesterone level at presentation (step 1) and the serum human chorionic gonadotropin (hCG) ratio, defined as the ratio of hCG at 48 h to hCG at presentation (step 2).

METHODS

This was a cohort study of 2753 PUL (301 EP), involving a secondary analysis of prospectively and consecutively collected PUL data from two London-based university teaching hospitals. Using a chronological split we used 1449 PUL for development and 1304 for validation. We aimed to assign PUL as low risk with high confidence (high negative predictive value (NPV)) while classifying most EP as high risk (high sensitivity). The first triage step assigned PUL as low risk using a threshold of serum progesterone at presentation. The remaining PUL were triaged using a novel logistic regression risk model based on hCG ratio and initial serum progesterone (second step), defining low risk as an estimated EP risk of < 5%.

RESULTS

On validation, initial serum progesterone ≤ 2 nmol/L (step 1) classified 16.1% PUL as low risk. Second-step classification with the risk model selected an additional 46.0% of all PUL as low risk. Overall, the two-step protocol classified 62.1% of PUL as low risk, with an NPV of 98.6% and a sensitivity of 92.0%. When the risk model was used in isolation (i.e. without the first step), 60.5% of PUL were classified as low risk with 99.1% NPV and 94.9% sensitivity.

CONCLUSION

PUL can be classified efficiently into being either high or low risk for complications using a two-step protocol involving initial progesterone and hCG levels and the hCG ratio. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Validation of MALDI-TOF MS for rapid classification and identification of lactic acid bacteria, with a focus on isolates from traditional fermented foods in Northern Vietnam

AIMS

To evaluate the potential use of MALDI-TOF MS for fast and reliable classification and identification of lactic acid bacteria (LAB) from traditional fermented foods.

METHODS AND RESULTS

A total of 119 strains of LAB from fermented meat (nem chua) were analysed with both (GTG)(5)-PCR fingerprinting and MALDI-TOF MS. Cluster analysis of the profiles revealed five species represented by a single isolate both in (GTG)(5)-PCR and in MALDI-TOF MS; five species grouped alike for (GTG)(5)-PCR and for MALDI-TOF MS; however, differences in minimal similarity between the delineated (GTG)(5)-PCR and MALDI-TOF MS clusters could be observed; three species showed more heterogeneity in their MALDI-TOF MS profiles compared to their (GTG)(5)-PCR profiles; two species, each represented by a single MALDI-TOF cluster, were subdivided in the corresponding (GTG)(5)-PCR dendrogram. As proof of the identification potential of MALDI-TOF MS, LAB diversity from one fermented mustard sample was analysed using MALDI-TOF MS. PheS gene sequencing was used for validation.

CONCLUSIONS

MALDI-TOF MS is a powerful, fast, reliable and cost-effective technique for the identification of LAB associated with the production of fermented foods.

SIGNIFICANCE AND IMPACT OF THE STUDY

Food LAB can be identified using MALDI-TOF MS, and its application could possibly be extended to other food matrices and/or other food-derived micro-organisms.

Lobular and non-lobular breast cancers differ regarding axillary lymph node metastasis: a cross-sectional study on 4,292 consecutive patients

Invasive lobular carcinoma (ILC) accounts for 8-14% of all breast cancers and carries distinct prognostic and biologic implications. The goal of our study was to investigate the impact of lobular histology on axillary lymph node (ALN) involvement. This is a cross-sectional study of 4,292 consecutive patients surgically treated for breast carcinoma at the University Hospitals Leuven. Logistic regression analysis was used to relate ILC to lymph node involvement while controlling for the following clinicopathologic features: tumor size, multifocal disease, tumor grade, lobular subtype and the combined steroid, and Her-2 status. Odds ratios (ORs) and 95% confidence intervals (CIS) were computed. A subgroup analysis was performed for patients that underwent a sentinel lymph node (SLN) procedure. The observed incidence of ILC was 13%. ILCs were larger, were more often grade II, multifocal, steroid receptor positive and Her-2 negative, and tended to be present in older patients. Incidence of ALN involvement was 42.0% for ILCs versus 38.3% for other tumors (OR 1.17, 95% CI 0.97-1.40). For the SLN subgroup, ILCs were less often ALN positive than non-ILCs (20.5% versus 28.3%, OR 0.66, 95% CI: 0.41-1.00). In the multivariable analysis, the lobular subtype was identified as less likely to have ALN involvement (adjusted OR 0.66, 95% CI 0.53-0.82). The analysis for the SLN subgroup showed comparable results (adjusted OR 0.49, 95% CI 0.30-0.78). This study has demonstrated that the lobular subtype is an independent predictor of lymph node involvement with ILC having a lower incidence of involved lymph nodes. The mildly higher incidence of ALN metastasis in lobular cancers in univariable analysis is not due to the lobular subtype, but due to confounding factors that interact with lymph node involvement.

In Vitro Assessment of the Gastrointestinal Transit Tolerance of Taxonomic Reference Strains from Human Origin and Probiotic Product Isolates of Bifidobacterium

Next to health promoting effects, the functional aspect of probiotic strains also involves their capacity to reach the colon as viable metabolically active cells. The present study aimed to assess the potential of 24 probiotic product isolates and 42 human reference strains of Bifidobacterium to survive gastrointestinal transit under in vitro conditions. The survival capacity of exponential and stationary phase cultures upon exposure to gastric and small intestinal juices was determined using a recently developed microplate-based assay in combination with the LIVE/DEAD BacLight Bacterial Viability kit. All 66 strains tested displayed a considerable loss in viability during exposure to an acidic pepsin containing solution (pH 2.0). Among the 10 taxa tested, cultures of B. animalis ssp. lactis appeared to be most capable to survive gastric transit. Although to a lesser extent, the presence of bile salts also affected the viability of most of the strains tested. Except for 3 strains, all 66 strains showed bile salt hydrolase activity using an agar-based assay. In contrast, the bifidobacterial strains used in this study appeared to possess a natural ability to survive the presence of pancreatin (pH 8.0). Although the effect was not significant, a slightly enhanced tolerance to gastrointestinal transit was observed when cells were in the stationary phase, especially when exposed to acid, compared with cells being in the exponential phase. Survival in the gastrointestinal tract appeared to be largely strain-dependent and hence implies that different strains will likely display a different behavior in functionality. The assay used in this study allows an initial assessment of strains for use as probiotic cultures prior to selecting potential candidate strains for further investigation in vivo.

Antimicrobial susceptibility of Bifidobacterium strains from humans, animals and probiotic products

OBJECTIVES

The aim of this study was to assess the antimicrobial susceptibility of a taxonomically diverse set of Bifidobacterium strains to different classes of antimicrobial agents using a recently described medium.

METHODS

The susceptibility of 100 strains encompassing 11 bifidobacterial species originating from humans, animals and probiotic products to 12 antimicrobial agents was tested by agar overlay disc diffusion. Based on these results, one or two strains per species were selected for susceptibility testing to nine antibiotics by broth microdilution using the Lactic acid bacteria Susceptibility test Medium (LSM) supplemented with cysteine. The genotypic basis of atypical tetracycline resistance was further characterized using PCR, Southern blotting and partial sequencing.

RESULTS

Based on the distribution of inhibition zone diameters and MIC values, all strains tested were susceptible to amoxicillin, chloramphenicol, erythromycin, quinupristin/dalfopristin, rifampicin and vancomycin. Our data also reinforce earlier observations indicating that bifidobacteria are intrinsically resistant to gentamicin, sulfamethoxazole and polymyxin B. Susceptibility to trimethoprim, trimethoprim/sulfamethoxazole, ciprofloxacin, clindamycin, tetracycline and minocycline was variable. The tet(W) gene was responsible for tetracycline resistance in 15 strains including 7 probiotic isolates belonging to the taxa Bifidobacterium animalis subsp. lactis and Bifidobacterium bifidum. This gene was present in a single copy on the chromosome and did not appear to be associated with the conjugative transposon TnB1230 previously found in tet(W)-containing Butyrivibrio fibrisolvens.

CONCLUSIONS

The use of the LSM + cysteine medium allowed us to discriminate between intrinsic and atypical resistance properties of bifidobacteria and sets the scene for future definition of epidemiological cut-off values for all important Bifidobacterium species. The presence of an acquired tet(W) gene in several probiotic product isolates stresses the need for a minimal safety evaluation during the selection of Bifidobacterium strains for probiotic use.