Pleural effusion-related Nocardia otitidiscaviarum, Anaplasma platys and Ehrlichia canis coinfection in a dog.

The coinfections by some microorganisms have been related to severe diseases in humans and animals, where immunosuppressive agents favor opportunistic behavior of other pathogens. A 4-month-old, female mixed-breed dog with a two-week history of inappetence, prostration, emaciation, and respiratory distress was admitted at a veterinary hospital in Brazil. Tachycardia, pale mucous membranes, severe respiratory distress, and a large number of ticks (Rhipicephalus sanguineus s.l.) in different body regions were observed at clinical examination. Hematological examination of dog showed leukocytosis, neutrophilia, mild anemia, and thrombocytopenia, whereas unremarkable values in biochemical tests. Thoracic radiography revealed a pleural effusion image. Blood and the pleural fluid (purulent aspect) samples were subjected to qPCR (16S rRNA and dsb genes) and sequencing, which identified Ehrlichia canis and Anaplasma platys coinfection. An aggregate of coccoid-to-branching or long filamentous microorganisms, surrounded by pyogranulomatous inflammatory reaction was seen at the cytology of the pleural fluid. Bacteriological culture of pleural effusion showed colonies compatible with the genus Nocardia, which revealed gram-positive filamentous organisms with a tendency of fragmentation and were identified as Nocardia otitidiscaviarum in mass spectrometry (MALDI-TOF MS). Therapy of N. otitidiscaviarum isolate using levofloxacin (supported by a previous in vitro susceptibility testing) and doxycycline for E. canis and A. platys resulted in complete resolution of the clinical picture. Here, we report for the first time a triple coinfection by Nocardia otitidiscaviarum, A. platys, and E. canis in a dog with pleural effusion, where debilitating or immunosuppressive conditions induced by A. platys and E. canis coinfection probably contributed to the opportunistic behavior of N. otitidiscaviarum.

Bacterial identification in cerebrospinal fluid of domestic species with neurologic signs: a retrospective case-series study in 136 animals (2005-2021).

Central nervous system (CNS) infections comprise life-threatening clinical conditions in domestic species, and are commonly related to severe sequelae, disability, or high fatality rates. A set of bacterial pathogens have been identified in central nervous infections in livestock and companion animals, although the most of descriptions are restricted to case reports and a lack of comprehensive studies involving CNS-related bacterial infections have been focused on a great number of domestic species. In this scenario, we retrospectively investigated selected epidemiological data, clinical findings, bacteriological culture, and in vitro susceptibility patterns of 136 nonrepetitive neurologic cases in domestic species (2005-2021). Bacterial isolates were recovered from 25% (34/136) of the cerebrospinal fluid (CSF) sampled. The isolates were obtained from cattle (9/136 = 6.6%), dogs (7/136 = 5.1%), horses (6/136 = 4.4%), goats (3/136 = 2.2%), pigs (3/136 = 2.2%), sheep (3/136 = 2.2%), cats (2/136 = 1.5%), and asinine (1/136 = 0.7%). Among animals with bacterial isolation, Staphylococcus aureus (6/34 = 17.6%), Escherichia coli (5/34 = 14.7%), Staphylococcus beta-hemolytic (5/34 = 14.7%), and Trueperella pyogenes (3/34 = 8.8%) were predominant, in addition to a miscellaneous of other bacteria isolated in minor frequency, e.g., Corynebacterium pseudotuberculosis, Enterobacter cloacae, Mannheimia haemolytica, Pseudomonas aeruginosa, and Streptococcus equi subsp. equi. In vitro susceptibility tests of isolates revealed that amoxicillin/clavulanic acid (11/13 = 84.6%), cephalexin (9/11 = 81.8%), and florfenicol (9/12 = 75%) were the most effective antimicrobials. Conversely, isolates exhibited resistance mainly to tetracycline (6/10 = 60%), penicillin (6/11 = 54.5%), and trimethoprim/sulfamethoxazole (5/11 = 45.5%). Also, multidrug resistance to ≥ 3 classes of antimicrobials was found in 23.5% (8/34) strains. Data relative to the outcome was available in 79.4% (27/34) of animals that had bacterial isolation, and from these, the lethality rate was 92.6% (25/27). Incoordination (14/34 = 41.2%), recumbency (11/34 = 32.4%), apathy (10/34 = 29.4%), anorexia (9/34 = 26.5%), blindness (7/34 = 20.6%), seizure (6/34 = 17.6%), limb paresis (5/34 = 14.7%), head-pressing (4/34 = 11.8%), and nystagmus (3/34 = 8.8%) were the most frequent clinical signs. A variety of bacterial pathogens were identified in the CSF of domestic species showing neurologic signs, with a predominance of staphylococci, streptococci, and enterobacteria. High lethality of cases, poor in vitro efficacy of conventional antimicrobials, and a high in vitro multidrug resistance pattern of isolates were seen. Our results contribute to etiological characterization, antimicrobial resistance patterns, and clinical-epidemiological findings of bacterial infections in domestic species with neurological signs.

Klebsiella-induced infections in domestic species: a case-series study in 697 animals (1997-2019).

Klebsiella species, particularly K. pneumoniae, are well-known opportunistic enterobacteria related to complexity of clinical infections in humans and animals, commonly refractory to conventional therapy. The domestic animals may represent a source of the pathogenic and multidrug-resistant Klebsiella species to humans. Nevertheless, most studies involving Klebsiella-induced infections in domestic animals are restricted to case reports or outbreaks. We retrospectively investigated selected epidemiological data, clinical aspects, and in vitro susceptibility pattern of 697 non-repetitive Klebsiella infections in livestock and companion species (1997-2019). The isolates were obtained from different clinical disorders from dogs (n = 393), cattle (n = 149), horses (n = 98), cats (n = 27), pigs (n = 22), sheep (n = 5), goats (n = 2), and buffalo (n = 1), except four isolates from subclinical bovine mastitis. Urinary (223/697 = 32%), enteric (117/697 = 16.8%), mammary (85/697 = 12.2%), reproductive (85/697 = 12.2%), and respiratory disorders (67/697 = 9.6%) were the most common clinical manifestations. Other miscellaneous clinical pictures (116/697 = 16.6%) included abscesses, otitis, hepatitis, conjunctivitis, pyodermitis, sepsis, and encephalitis. Norfloxacin (183/245 = 74.7%) and gentamicin (226/330 = 68.5%) were the most effective antimicrobials. High in vitro resistance of the isolates was seen to ampicillin (326/355 = 91.8%), amoxicillin/clavulanic acid (25/62 = 40.3%), and trimethoprim/sulfamethoxazole (100/252 = 39.7), and multidrug resistance to ≥ 3 classes of antimicrobials was found in 20.4% (142/697) isolates. Wide variety of clinical manifestations of Klebsiella-induced infections was observed, with a predominance of urinary, enteric, mammary, reproductive, and respiratory tract disorders, reinforcing opportunistic behavior of agent. Poor in vitro efficacy was observed to some conventional antimicrobials and ~ 20% of isolates exhibited resistance pattern, reinforcing the need for proper use of drugs on therapy approaches in domestic animals to avoid multidrug-resistant bacteria, an emergent global concern.

Bacteriological, cytological, and molecular investigation of Corynebacterium pseudotuberculosis, mycobacteria, and other bacteria in caseous lymphadenitis and healthy lymph nodes of slaughtered sheep.

Caseous lymphadenitis (CL) in sheep is a chronic contagious disease caused by Corynebacterium pseudotuberculosis, commonly characterized by abscess formation in peripheral lymph nodes and disseminated infections. Nonetheless, other microorganisms, including with zoonotic relevance, can be isolated from CL-resembling lymph nodes. Currently, mycobacteria have been reported in visceral granulomatous lesions in small ruminants, a fact that poses a public health issue, particularly in slaughtered sheep intended for human consumption. Cytology using fine needle aspiration and microbiological culturing are suitable tests for routine diagnostic, whereas present drawbacks and molecular methods have been confirmatory. Data about the occurrence of mycobacteria in both lymph nodes with aspect of CL and apparently healthy visceral nodes of sheep slaughtered for human consumption are scarce. In this study, 197 visceral lymph nodes of sheep showed lymphadenitis and 202 healthy visceral lymph nodes of slaughtered sheep intended for human consumption were submitted to conventional bacteriological diagnosis, mycobacteria culturing, and cytological evaluation. Compatible Corynebacterium isolates were subjected to multiplex PCR targeting 16S rRNA, rpoB, and pld genes to detect C. pseudotuberculosis. Based on microbiological identification, C. pseudotuberculosis (86/197; 43.7%), streptococci γ-hemolytic (17/197; 8.6%), and Trueperella pyogenes (12/197; 6.1%) were prevalent in lymph nodes with abscesses, as opposed to staphylococci (53/202; 26.2%) in apparently healthy lymph nodes. No mycobacteria were isolated. Cytology identified 49.2% (97/197) Gram-positive pleomorphic organisms (coryneform aspect). Multiplex PCR confirmed genetic material of C. pseudotuberculosis in 74.4% (64/86) of the samples with C. pseudotuberculosis isolation and 66% (64/97) samples with cytological coryneform aspect (κ = 86.78%; 95% CI = 79.87-93.68%). These findings emphasize the prevalence of C. pseudotuberculosis in abscess formation among peripheral lymph nodes of sheep. Other bacteria were also identified in lymph nodes sampled that resembling C. pseudotuberculosis-induced infections that may difficult the diagnosis. Multiplex PCR revealed a valuable assay to detect C. pseudotuberculosis, in addition to routine methods applied to CL-diagnosis. No mycobacteria were identified in lymph nodes sampled, with and without apparent lesions. Nonetheless, due to public health impacts, this pathogen should be considered as a differential diagnosis of C. pseudotuberculosis-induced infections during inspection procedures of slaughtered sheep intended for human consumption.