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The etiology of otitis in dogs and cats is multifactorial and complex, involving bacterial and fungal pathogens. As empiric antimicrobial prescription is a common practice when treating such cases, antimicrobial resistance may represent a complicating factor. The aim of this study was to describe microbiological features and susceptibility profiles of pathogens associated with 142 cases of external otitis, comprising 138 dogs and 4 cats.. The specimens were processed to identify bacterial and fungal etiologies following standard microbiological methods. Antimicrobial susceptibility was determined in vitro against 15 antibiotics and 3 antifungals. Further, Staphylococcus spp. isolates were screened for the detection of β-lactamase enzymes using cefinase paper discs. Pseudomonas spp. and isolates from Enterobacteriaceae family were screened for colistin (Polymyxin E) resistance and for the mcr-1-mediated colistin resistance gene by PCR. The presence of mixed cultures of Enterobacteriaceae, Pseudomonas spp. and Staphylococcus spp., and co-infections with Malassezia spp., emphasizes the polymicrobial etiology of external otitis in small animals. Emerging rates of multidrug resistance observed in almost 50% of the isolates may alert for a near future of challenging veterinary cases unresponsive to first-line antimicrobials. In addition, these results highlight a potential public health concern of multidrug resistant bacteria, given the proximity of pets and their owners. This study addressed central aspects of external otitis, providing microbiologists and clinicians updated information on the etiology and treatment of challenging cases of multidrug resistant bacteria. It also provides priceless surveillance value in monitoring resistant bacteria in small animals.

Several studies have shown the ubiquitous presence of bacteria in the hospital environmental surfaces, staff, and patients. Frequently, these bacteria are related to HAI (healthcare-associated infections) and carry antimicrobial resistance (AMR). These HAI-related bacteria contributes to a major public health issue by increasing patient morbidity and mortality during or after hospital stay. Bacterial high-throughput amplicon gene sequencing along with AMR genes identification and whole genome sequencing (WGS) are new biotechnological tools that allow multiple-sample screening for a diversity of bacteria. In this paper, we used these methods to perform an one-year cross sectional profiling of bacteria and AMR genes in adult and neonatal intensive care units (ICU and NICU) in a Brazilian public hospital. Our results showed high abundances of HAI-related bacteria as S. epidermidis, S. aureus, K. pneumoniae, A. baumannii complex, E. coli, E. faecalis and P. aeruginosa in patients and hospital surfaces. Most abundant AMR genes detected throughout ICU and NICU were mecA, blaCTX-M-1 group, blaSHV-like and blaKPC-like. We found that NICU environment and patients were more widely contaminated with pathogenic bacteria than ICU. Patient samples, despite the higher bacterial load, have lower bacterial diversity than environmental samples in both units. Finally, we also identified contamination hotspots in the hospital environment showing constant frequencies of bacterial and AMR contamination throughout the year. WGS sequencing, 16S rRNA oligotypes and AMR identification allowed a high-resolution data analysis for bacterial characterization and its distributions along the hospital microbiome profile.

Colistin antimicrobial susceptibility testing (AST) has been acknowledged as challenging, and recently EUCAST has posted warnings regarding the gradient tests, which have been used for testing by many clinical laboratories. Current EUCAST recommendations state that only broth microdilution (BMD) should be used for AST of colistin. In a recently published paper three methods for colistin AST were compared against a collection of Enterobacteriaceae clinical isolates (83 colistin-resistant and 40 colistin-susceptible). In addition to BMD used as a reference, the authors used the Phoenix automated AST method, and the Rapid Polymyxin NP test. The latter is a colorimetric test based on formation of acid metabolites consecutive to the glucose metabolism as a sign of growth in the presence of colistin (colistin resistance). The Phoenix system failed to detect ten colistin-resistant isolates (one Escherichia coli , one Klebsiella pneumoniae , seven Enterobacter spp., and one Salmonella enterica ), whereas The Rapid Polymyxin NP test failed to detect the same single E. coli isolate. The EUCAST Development Laboratory will investigate the performance of the Rapid Polymyxin NP test in a separate investigation versus a strain collection with low-level resistance to colistin. Based on the results in this investigation there will be a decision on whether the Rapid Polymyxin NP test can be recommended by EUCAST as one possible method for colistin AST, and whether there are some caveats. Meanwhile, clinical laboratories, particularly larger university laboratories with complex patients, should acknowledge the increasing need for reference AST, and preferably implement BMD.

In context with the first communication which deals with the characterization of the so-called brown contamination called forth by Enterobacteriaceae in the citric acid fermentation of molasses, the present paper describes the screening of antiseptic substances able to suppress the contamination mentioned without damaging the normal growth of the producing mould Aspergillus niger and its ability of producing citric acid. Among the substances tested the sodium salt of 5-nitrofurylacrylic acid (5-NFA) excelled partly because of its antiseptic effect in relatively small concentrations and partly because the mould tolerates appreciable amounts of this antiseptic. Therefore there may be applied, in the presence of a heavy contamination, relatively high concentrations of the antiseptic without fear of damaging the producing mould. Usually a dose of 10 to 15 mg 5-NFA in 11 of medium was sufficient to suppress the brown contamination.