One potential solution to the rising threat of antibacterial drug resistance is the application of therapeutic clays to treat wound infections. Clays with antibacterial activity have been identified from a range of sources with their antibacterial properties often attributed to the release of toxic metal ions such as Fe(II) and Al(III). Here, clays from Afghanistan, Azerbaijan and Bangladesh that are utilized for washing and healing purposes were examined. Their antibacterial activities were assessed in suspension and as aqueous leachates against representative Gram-negative, Escherichia coli, and Gram-positive, Bacillus subtilis, bacteria. The majority of the clays conferred no deleterious effect and, in fact, tended to promote bacterial growth, likely as a result of released organic and inorganic nutrients. However, one of the clays, obtained from the Dhaka region of Bangladesh, displayed significant bactericidal activity against E. coli and B. subtilis as a clay suspension but not as an aqueous leachate. Further experiments confirmed that contact between clay and the bacteria was necessary for most of the antibacterial effects. Detailed analysis of bulk and <2 μm clay fraction mineralogy and geochemistry revealed no single defining parameter or mineral component that could be used to easily distinguish natural clays with antibacterial properties from those without. Overall, the results suggest a mechanism of antibacterial action of the Dhaka clay that arises from acidic conditions, likely enabled by the absence of calcite in the bulk clay, metal release, the presence of interstratified chlorite-smectite, and direct clay–bacteria interactions.

This research communication addresses the hypothesis that double premilking teat disinfection (DD) is more effective in reducing soiling and bacterial count on the cows' teat skin and milkers' gloves than conventional disinfection (CONV). The design was a 3 × 3 Latin square (three groups of cows and three treatments) with conventional teat disinfection (CONV, lactic acid application after forestripping), double teat disinfection using the same disinfectant (DD1D, lactic acid application before and after forestripping), and double teat disinfection using two different disinfectants (DD2D, application of lactic acid before and chlorine-based disinfectant after forestripping). All groups were assigned for six days for each treatment, and the evaluations and samples were collected on the last day, before and after treatment. We evaluated the teat cleanliness score (TCS), count of Gram-negative bacteria (coliforms and noncoliforms), Staphylococcus spp., Streptococcus spp., and total bacterial count (TBC) on the cows' teats and TBC on the milkers' gloves. TCS after premilking was lower in DD than CONV treatment. The reduction of Staphylococcus spp. count was greater in the DD treatment and tended to be higher in the DD2D. The TBC reduction on the cows' teats was greater in the DD treatments. The TBC on the milkers' gloves was lower for DD before and after premilking. In conclusion, DD can be an alternative for reducing some bacterial populations on cow teats and preventing the transmission of microorganisms between cows via the milkers' hands.

Burden of bacteraemia is rising due to increased average life expectancy in developed countries. This study aimed to compare the epidemiology and outcomes of bacteraemia in two similarly ageing populations with different ethnicities in Singapore and Denmark. Historical cohorts from the second largest acute-care hospital in Singapore and in the hospitals of two Danish regions included patients aged 15 and above who were admitted from 1 January 2006 to 31 December 2016 with at least 1 day of hospital stay and a pathogenic organism identified. Among 13 144 and 39 073 bacteraemia patients from Singapore and Denmark, similar 30-day mortality rates (16.5%; 20.3%), length of hospital stay (median 14 (IQR: 9–28) days; 11 (6–21)), and admission rate to ICU (15.5%; 15.6%) were observed, respectively. Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus ranked among the top four in both countries. However, Singaporeans had a higher proportion of patients with diabetes (46.8%) and renal disease (29.5%) than the Danes (28.0% and 13.7%, respectively), whilst the Danes had a higher proportion of patients with chronic pulmonary disease (18.0%) and malignancy (35.3%) than Singaporeans (9.7% and 16.2%, respectively). Our study showed that top four causative organisms and clinical outcomes were similar between the two cohorts despite pre-existing comorbidities differed.

In this Research Communication we evaluate the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify 380 bacteria isolated from cases of bovine mastitis in Brazil. MALDI-TOF MS identifications were compared to previous identifications by biochemical tests and 16S rRNA sequencing. MALDI-TOF MS achieved a typeability of 95.5%. The accuracy of MALDI-TOF MS for the identification of Staphylococcus isolates was 93.2%. The agreement between MALDI-TOF MS and biochemical identification of Streptococcus agalactiae was 96%, however, the agreement between these techniques for identifying other catalase-negative, Gram-positive cocci was lower. Agreement in identifying Gram-negative bacteria at the genus level was 90.5%. Our findings corroborate that MALDI-TOF MS is an accurate, rapid and simple technique for identifying bovine mastitis pathogens. The availability of this methodology in some research institutions would represent a significant step toward increasing the diagnosis and epidemiological studies of bovine mastitis and other animal infectious diseases in Brazil.

Antibiotic-resistant Gram-negative bacteraemias (GNB) are increasing in incidence. We aimed to investigate the impact of empirical antibiotic therapy on clinical outcomes by carrying out an observational 6-year cohort study of patients at a teaching hospital with community-onset Escherichia coli bacteraemia (ECB), Klebsiella pneumoniae bacteraemia (KPB) and Pseudomonas aeruginosa bacteraemia (PsAB). Antibiotic therapy was considered concordant if the organism was sensitive in vitro and discordant if resistant. We estimated the association between concordant vs. discordant empirical antibiotic therapy on odds of in-hospital death and ICU admission for KPB and ECB. Of 1380 patients, 1103 (79.9%) had ECB, 189 (13.7%) KPB and 88 (6.4%) PsAB. Discordant therapy was not associated with increased odds of either outcome. For ECB, severe illness and non-urinary source were associated with increased odds of both outcomes (OR of in-hospital death for non-urinary source 3.21, 95% CI 1.73–5.97). For KPB, discordant therapy was associated with in-hospital death on univariable but not multivariable analysis. Illness severity was associated with increased odds of both outcomes. These findings suggest broadening of therapy for low-risk patients with community-onset GNB is not warranted. Future research should focus on the relationship between patient outcomes, clinical factors, infection focus and causative organism and resistance profile.

The prevalence of antimicrobial resistance (AMR) varies significantly among different patient populations. We aimed to summarise AMR prevalence data from screening studies in different patient settings in Switzerland and to identify surveillance gaps. We performed a systematic review, searching Pubmed, MEDLINE, Embase (01/2000–05/2017) and conference proceedings for Swiss studies reporting on carbapenemase-producing Enterobacteriaceae (CPE), extended-spectrum beta-lactamases (ESBL), mobilised colistin-resistance, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) within different patient settings. We identified 2345 references and included 46 studies. For acute care patients, most screening data come from admission screenings, whereas AMR prevalence among hospitalised patients is largely unknown. Universal admission screenings showed ESBL-prevalences of 5–8% and MRSA-prevalences of 2–5%. For targeted screening, ESBL-prevalence ranged from 14–21%; MRSA-prevalence from 1–4%. For refugees, high ESBL (9–24%) and MRSA (16–24%) carriage rates were reported; returning travellers were frequently (68–80%) colonised with ESBL. Screening data for other pathogens, long-term care facility (LTCF) residents and pediatric populations were scarce. This review confirms high ESBL- and MRSA-carriage rates for risk populations in Switzerland. Emerging pathogens (CPE and VRE) and certain populations (inpatients, LTCF residents and children) are understudied. We encourage epidemiologists and public health authorities to consider these findings in the planning of future surveillance studies.

Acinetobacter is a well-recognized nosocomial pathogen. Previous reports of community-associated Acinetobacter infections have lacked clear case definitions and assessment of healthcare-associated (HCA) risk factors. We identified Acinetobacter bacteraemia cases from blood cultures obtained <3 days after hospitalization in rural Thailand and performed medical record reviews to assess HCA risk factors in the previous year and compare clinical and microbiological characteristics between cases with and without HCA risk factors. Of 72 Acinetobacter cases, 32 (44%) had no HCA risk factors. Compared to HCA infections, non-HCA infections were more often caused by Acinetobacter species other than calcoaceticus–baumannii complex species and by antibiotic-susceptible organisms. Despite similar symptoms, the case-fatality proportion was lower in non-HCA than HCA cases (9% vs. 45%, P < 0·01). Clinicians should be aware of Acinetobacter as a potential cause of community-associated infections in Thailand; prospective studies are needed to improve understanding of associated risk factors and disease burden.

Newborns often present with skin conditions ranging from transient benign to severe. An occasional cause of neonatal exanthemic rash is infection due to Gram-positive bacteria, but Gram-negative infection is uncommon. We describe an outbreak of sepsis in 10 neonates over a 2-week period, caused by Klebsiella pneumoniae in a level III neonatal intensive care unit (NICU). Seven babies developed an exanthematous maculopapular rash. Molecular analysis by pulsed-field gel electrophoresis showed that all the babies with rash were infected by a single strain of K. pneumoniae which was distinct from the strain recovered from babies without rash.

The emergence of multidrug resistance among gram-negative bacilli is complex. Numerousfactors need to be considered, including the biological fitness cost of resistance, fitnesscompensatorymutations and frequency and type of antibiotic exposure. A mathematical modelevaluating these complex relationships was developed in an individual colonized with strains ofpan-susceptible, single-, two- and multidrug-resistant (MDR) gram-negative bacilli (GN). The effectof bacterial fitness, compensatory mutations and the frequency of three-antimicrobial regimenexposure to predominance of multidrug-resistant strains were quantified. The model predicts thatinitially, in the absence of antibiotic exposure, the biologically fitter pan-susceptible strain predominatesover the resistant strains. Over time, the fitness of the MDR strains increases fasterwith repeated antimicrobial exposure, through compensatory-fitness mutations. Increasing thefrequency of exposure to the three-antimicrobial regimen or, increasing the initial fitness of theresistant strains, substantially decreases the time to MDR-GN predominance. The model impliesthat when MDR-GN strains evolve into strains that are fitter than susceptible strains, a reductionin antimicrobial exposure may not result in a decrease of MDR-GN, since the absence of selectiveantimicrobial pressure would no longer favor susceptible strains. The model also implies thatantimicrobial cycling may promote the emergence of MDR-GN.