An epizootiological study was carried out by investigation of 562 birds for mycoplasmas. The birds belonged to 18 different domestic and wild avian species of the following orders: Galliformes, Anseriformes, Gruiformes, Passeriformes, Columbiformes, Falconiformes, Psittasiformes and Trogoniformes. Eighty nine (15%) of the trachea and oropharynx samples examined were mycoplasma positive and 108 mycoplasma isolates were obtained and identified by the growth inhibition test, using rabbit antisera against fifteen avian mycoplasma species. The species most frequently detected were Mycoplasma gallinarum (27.7%), M. gallinaceum (17.5%), M. iners (14.8%), M. pullorum (7.4%), M. columbinum (7.4%), M. anatis (6.4%), M. synoviae (4.6%) and M. gallisepticum (3.7%). Four strains isolated from griffon vultures (Gyps fulvus) could not be identified with antisera against the 15 described avian mycoplasma species.

A total of 120 mycoplasma strains were recovered from 97 of 265 diseased seals investigated during the seal epidemic in the North Sea and in the Baltic Sea in 1988. Mycoplasmas were isolated from the respiratory tracts (including lungs), hearts, brains, and eyes of the seals. Thirty strains were filter cloned and investigated for their morphological, biochemical, and serological characteristics compared with the characteristics of previously described species. The results of an indirect immunofluorescence test, a growth inhibition test, and an immunobinding assay showed that these strains belong to two new species, for which the names Mycoplasma phocarhinis and Mycoplasma phocacerebrale are proposed. M. phocarhinis (17 strains) did not ferment glucose or hydrolyze arginine but did reduce tetrazolium chloride and potassium tellurite and produced films and spots. M. phocacerebrale (13 strains) metabolized arginine but not glucose and produced phosphatase but did not reduce tetrazolium chloride and potassium tellurite. Both species lysed sheep erythrocytes but did not absorb sheep or guinea pig erythrocytes. The type strain of M. phocarhinis is strain 852 (= ATCC 49639), and the type strain of M. phocacerebrale is strain 1049 (= ATCC 49640).

The role of sdiA in the acquisition of low-level multidrug resistance (MDR) was analysed and compared with that of marA and soxS in two Escherichia coli clinical isolates and two in vitro-selected mutants. The mutants were developed by growth in lomefloxacin and ceftazidime. The sdiA, marA, soxS, ftsI, tolC and acrB gene transcript levels were determined by RT–PCR. Analyses of 2,4-dinitrophenol susceptibility, the effect of an active efflux inhibitor on antibiotic and mitomycin C susceptibility, β-lactamase hydrolytic activity, outer and inner membrane proteins and acrR gene sequencing were also performed. Both mutants showed elevated marA and sdiA gene transcript levels, which were associated with increased susceptibility to 2,4-dinitrophenol; soxS overexpression was only seen in the mutant selected with ceftazidime. The two mutants showed MDR phenotypes in which ceftazidime, cefpirome and aztreonam MICs increased 4- to 128-fold, in addition to decreased susceptibility to quinolones, chloramphenicol and mitomycin C. The highest ceftazidime MIC in one of the mutants coincided with a frameshift mutation in acrR and the highest transcript level of ftsI (penicillin-binding protein 3), but not with a higher β-lactamase activity. Likewise, active efflux associated with increased levels of acrB and tolC and decreased OmpF expression contributed to low-level MDR in both mutants. marA and sdiA overexpression was a common feature of multidrug-resistant mutants selected by growth in lomefloxacin and ceftazidime. To our knowledge, this report is the first to describe in vitro selection with a fluoroquinolone or ceftazidime triggering sdiA overexpression in E. coli isolates.

A retrospective study of microbiological laboratory results from 2020 to 2022, obtained from a veterinary diagnostic laboratory of the island of Gran Canaria, Spain, focused on canine otitis cases, was performed. The objective of this study was to analyze the pathogen distribution, antimicrobial susceptibility, prevalence of multidrug resistant phenotypes and the role of coinfections in otitis cases in order to provide up-to-date evidence that could support effective control strategies for this prevalent pathology. A total of 604 submissions were processed for the diagnosis of canine external otitis. Of the samples analyzed, 472 were positive for bacterial or fungal growth (78.1%; 95% CI: 74.8–81.4%). A total of 558 microbiological diagnoses were obtained, divided in 421 bacterial (75.4%; 95% CI: 71.8–79.0%) and 137 fungal (24.6%; 95% CI: 20.9–28.1%) identifications. Staphylococcus pseudintermedius, Malassezia pachydermatis and Pseudomonas aeruginosa were the most prevalent microorganisms detected in clinical cases of otitis. High level antimicrobial resistance was found for Pseudomonas aeruginosa (30.7%), Proteus mirabilis (29.4%), Staphylococcus pseudintermedius (25.1%) and Escherichia coli (19%). Multidrug-resistant phenotypes were observed in 47% of the bacteria isolated. In addition, a 26.4% prevalence of methicillin-resistant Staphylococcus pseudintermedius was detected. The high prevalence of antimicrobial resistant phenotypes in these bacteria highlights the current necessity for constant up-to-date prevalence and antimicrobial susceptibility data that can support evidence-based strategies to effectively tackle this animal and public health concern.