The obligate and facultatively anaerobic bacterial flora of the normal feline gingival margin

Samples from the gingival margins of 14 cats considered normal on clinical examination were cultured for facultative and obligate anaerobic bacteria. All mouths were free from any gingival marginal inflammation and tartar build-up; all cats were between 6 and 12 months of age. A mixed growth was obtained from all samples. The mean number of bacterial species per sample was 10.7 with a range of 7-16 isolates. Of the 150 isolates processed, 109 (72.66%) were obligate anaerobes. Of the facultatively anaerobic species, Actinomyces (including A. viscosus, A. hordeovulneris and A. denticolens) comprised 12%, Pasteurella multocida 9.33% of isolates and Propionibacterium species 6% of all isolates. Gram-negative bacilli belonging to the genera Bacteroides and Fusobacterium were isolated from 12 of the 14 samples, and comprised 77% of the obligate anaerobes isolated. Clostridium villosum comprised 10.1% of obligately anaerobic isolates, Wolinella species made up 6.42%, while 4.58% were Peptostreptococcus anaerobius. The most commonly isolated obligately anaerobic species was C. villosum and the most commonly isolated facultatively anaerobic species was P. multocida. These findings show a bacterial flora of the normal feline mouth which is very similar in composition to that of cat fight abscesses and feline pyothorax.     

Oral associated bacterial infection in horses: studies on the normal anaerobic flora from the pharyngeal tonsillar surface and its association with lower respiratory tract and paraoral infections

Two hundred and seventy bacterial isolates were obtained from the pharyngeal tonsillar surface of 12 normal horses and 98 obligatory anaerobic bacteria were characterised. Of these, 57 isolates belonging to 7 genera (Peptostreptococcus (1); Eubacterium (9); Clostridium (6); Veillonella (6); Megasphera (1); Bacteroides (28); Fusobacterium (6)) were identified, and 16 of these were identified to species level (P. anaerobius (1); E. fossor (9); C. villosum (1); B. fragilis (1); B. tectum (2); B. heparinolyticus (2)). Three hundred and twenty isolates were obtained from 23 samples from horses with lower respiratory tract (LRT) or paraoral (PO) bacterial infections. Of the 143 bacteria selected for detailed characterisation, obligate anaerobes accounted for 100 isolates, facultative anaerobes for 42 isolates and obligate aerobes for one isolate. Phenotypic characterisation separated 99 of the isolates into 14 genera. Among the obligately anaerobic species, Gram-positive cocci including P. anaerobius comprised 25% of isolates, E. fossor 11% and other Gram-positive rods (excluding Clostridium sp.) 18% of isolates. The Gram-negative rods comprised B. fragilis 5%, B. heparinolyticus 5%, asaccharolytic pigmented Bacteroides 3% and other Bacteroides 13%, while a so-far unnamed species of Fusobacterium (7%), and Gram-negative corroding rods (3%) were isolated. Among the facultatively anaerobic isolates, S. equi subsp. zooepidemicus accounted for 31% of isolates, followed by Pasteurella spp. 19%, Escherichia coli 17%, Actinomyces spp. 9%, Streptococcus spp. 9%. Incidental facultative isolates were Enterococcus spp. 2%, Enterobacter cloaceae 2%, Actinobacillus spp. 2% and Gram-negative corroding rods 5%. On the basis of the similarities (as determined by DNA hybridization data and/or phenotypic characteristics) of some of the bacterial species (e.g. E. fossor and B. heparinolyticus) isolated from both the normal pharyngeal tonsillar surfaces and LRT and PO diseases of horses, it is considered that the most likely source of bacteria involved in these disease processes is flora from the oral cavity.     

Aerobic and anaerobic bacterial isolates from horses with pneumonia or pleuropneumonia and antimicrobial susceptibility patterns of the aerobes

Frequency of aerobic and anaerobic isolates in 327 aspirates and in 123 pleural fluid samples from 327 horses with pneumonia or pleuropneumonia and antimicrobial susceptibility patterns of the aerobes were reported. Of the 327 horses, 75% survived, 20% were euthanatized, and 5% died. Tracheobronchial aspirates or pleural fluid specimens from 25 of the horses did not yield growth. Of the remaining 302 horses, 221 had only aerobic organisms isolated, whereas only anaerobes were isolated from 6 of the 302 horses. The remaining 75 horses had mixed aerobic and anaerobic bacterial infections. The survival rates for horses with aerobic only isolates was twice that of horses with anaerobic isolates. The aerobic bacteria most frequently isolated were beta-Streptococcus spp, Pasteurella spp, Escherichia coli, and Enterobacter spp. The anaerobic species most frequently isolated were Bacteroides spp and Clostridium spp.     

Aerobic Bacteria Occurring in the Vagina of Bitches with Reproductive Disorders

A retrospective survey was performed of aerobic bacterial species found in the vagina of 203 bitches with genital disorders, e.g. infertility, vaginitis, pyometra and puppy death. Escherichia coli, beta-hemolytic streptococci, Staphylococcus intermedius and Pasteurella multocida were the species most often isolated. From bitches with pyometra E. coli in pure culture was the most frequent isolate. In contrast, the majority of infertile bitches gave rise to mixed cultures, and no specific bacterial species was consistently associated with infertility. Thus, bacterial sampling from infertile bitches was concluded to be of low diagnostic value. Bacterial species isolated from the bitches having vaginitis were present in pure culture in 26.9% of the samples while nonspecific mixed cultures were obtained from 34.6% of the samples from these bitches. E. coli was the most frequently isolated bacterial species from bitches with dead puppies. However, in such cases it is important to relate the vaginal bacterial findings to autopsy findings and the results of bacteriological cultures of the pups.     

Recovery and identification of anaerobes in veterinary medicine: A 2-year experience

The examination of 300 specimens over a 2-year period in a veterinary diagnostic laboratory (1975–1977) revealed that of the specimens yielding bacteria, 56.3% contained anaerobes while 71.8% yielded facultative bacteria. Of the total specimens 26.6% proved to be sterile and 4.6% were unsuitable. The anaerobes which were isolated with the highest frequency from diseased animals belonged to the following genera: Clostridium, 46.0%; Bacteroides 15.1%; Fusobacterium, 14.3%; Actinomyces, 11.1%; and Propionibacterium, 5.6%. The culture method used in this study was based upon reducible solid media for primary isolation. Its efficiency compared favorably with what is commonly accepted as an effective recovery rate for anaerobes. However, the relative proportion of anaerobic genera obtained from veterinary clinical specimens was in direct contrast with specimens obtained in medical diagnostic laboratories. Because of this difference and the kinds of anaerobes most frequently encountered in veterinary medicine, it is believed that the culture method used in this study is more suitable to veterinary medicine than other methods more commonly employed in medical diagnostic laboratories.     

Identification of bacteria associated with feline chronic gingivostomatitis using culture-dependent and culture-independent methods

Feline chronic gingivostomatitis (FCGS) is a chronic inflammatory disease of the oral cavity that causes severe pain and distress. There are currently no specific treatment methods available and little is known regarding its aetiology, although bacteria are thought to play a major role. The purpose of this study was to identify the oral bacterial flora in normal and diseased cats. Oral swabs were obtained from the palatoglossal folds of eight cats (three normal and five FCGS) and were subjected to microbiological culture. Pasteurella pneumotropica and Pasteurella multocida subsp. multocida were the most prevalent species identified by culture methods in the normal and FCGS samples, respectively. Bacteria were also identified using culture-independent methods (bacterial 16S rRNA gene sequencing). For the normal samples, 158 clones were analysed and 85 clones were sequenced. Capnocytophaga canimorsus (10.8% of clones analysed) was the predominant species. Uncultured species accounted for 8.2% of clones analysed, and 43.7% of clones analysed represented potentially novel species. For the FCGS samples, 253 clones were analysed and 91 clones were sequenced. The predominant species was P. multocida subsp. multocida (51.8% of clones analysed). Uncultured species accounted for 8.7% of clones analysed, and 4.7% of clones analysed represented potentially novel species. It is concluded that the oral flora in cats with FCGS appears to be less diverse than that found in normal cats. However, P. multocida subsp. multocida is found to be significantly more prevalent in FCGS than in normal cats and consequently may be of aetiological significance in this disease.     

Profiling of virulence associated genes of Pasteurella multocida isolated from cattle

Pasteurella multocida is a causative agent of many major diseases of which haemorrhagic septiciemia (HS) in cattle & a buffalo is responsible for significant losses to livestock sector in India and south Asia. The disease outcome is affected by various host- and pathogen-specific determinants. Several bacterial species-specific putative virulence factors including the capsular and virulence associated genes have been proposed to play a key role in this interaction. A total of 23 isolates of P. multocida were obtained from 335 cases of various clinically healthy and diseased cattle. These isolates were examined for capsule synthesis genes (capA, B, D, E and F) and eleven virulence associated genes (tbpA, pfhA, toxA, hgbB, hgbA, nanH, nanB, sodA, sodC, oma87 and ptfA) by PCR. A total of 19 P. multocida isolates belonging to capsular type B and 4 of capsular type A were isolated. All isolates of capsular type B harboured the virulence associated genes: tbpA, pfhA, hgbA, sodC and nanH, coding for transferrin binding protein, filamentous hemagglutinin, haemoglobin binding protein, superoxide dismutase and neuraminidases, respectively; while isolates belonging to capsular type A also carried tbpA, pfhA, hgbA and nanH genes. Only 50 % of capsular type A isolates contained sodC gene while 100 % of capsular type B isolates had sodC gene. The gene nanB and toxA were absent in all the 23 isolates. In capsular type A isolates, either sodA or sodC gene was present & these genes did not occur concurrently. The presence of virulence associated gene ptfA revealed a positive association with the disease outcome in cattle and could therefore be an important epidemiological marker gene for characterizing P. multocida isolates.     

Characterization of Pasteurella multocida strains isolated from human infections

Isolates of Pasteurella multocida recovered from infected humans (n = 15) were characterized by traditional and molecular microbiological methods and were compared with cat-derived strains (n = 5). The most prevalent subspecies among strains from human infections was P. multocida subsp. septica (80%), and nearly all isolates showed a similar combination of virulence-associated genes. MLST analysis classified the 20 P. multocida strains into 16 different sequence types, and we assigned 11 new sequence types (ST), however, only one of those (ST 334) was shared by two human and one cat isolates. P. multocida subsp. septica strains formed a distinct phylogenetic group within the species. The strains showed resistance to erythromycin, clindamycin and sulfamethoxazole, and with two exceptions, resistance to tilmicosin was also detected. Each strain was susceptible to ampicillin, streptomycin, gentamycin, tetracycline, doxycycline, cefazolin, cefpodoxime, chloramphenicol, florfenicol and enrofloxacin. Common characteristics (virulence profile and antibiotic sensitivity pattern) shared by strains isolated from humans and cats support the view that domestic cats may serve as a potential reservoir for P. multocida.     

Antimicrobial resistance in bovine respiratory disease: Auction market- and ranch-raised calves

This study compared changes in prevalence and antimicrobial susceptibility of Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni in feedlot calves derived from the auction market (AUCT; n = 299) and from a single-ranch source (RANCH; n = 300). In the AUCT calves, the prevalence of Mannheimia haemolytica decreased, whereas Histophilus somni increased over the feeding period. The AUCT calves showed an increase in isolates not susceptible to tulathromycin for all bovine respiratory disease (BRD) pathogens, an increase in Pasteurella multocida and Histophilus somni isolates not susceptible to oxytetracycline, and an increase in Pasteurella multocida isolates not susceptible to florfenicol. In the RANCH calves, the prevalence of all 3 BRD pathogens was high at feedlot entry and decreased significantly during the study period. In RANCH calves, there was a significant increase in Pasteurella multocida isolates not susceptible to oxytetracycline, tulathromycin, and florfenicol. Surprisingly, there was a significant decrease in Mannheimia haemolytica isolates that were not susceptible to oxytetracycline, tilmicosin, and tulathromycin.     

Aerobic bacteria from mucous membranes, ear canals, and skin wounds of feral cats in Grenada, and the antimicrobial drug susceptibility of major isolates

In a 2-year period 54 feral cats were captured in Grenada, West Indies, and a total of 383 samples consisting of swabs from rectum, vagina, ears, eyes, mouth, nose and wounds/abscesses, were cultured for aerobic bacteria and campylobacters. A total of 251 bacterial isolates were obtained, of which 205 were identified to species level and 46 to genus level. A commercial bacterial identification system (API/Biomerieux), was used for this purpose. The most common species was Escherichia coli (N = 60), followed by Staphylococcus felis/simulans (40), S. hominis (16), S. haemolyticus (12), Streptococcus canis (9), Proteus mirabilis (8), Pasteurella multocida (7), Streptococcus mitis (7), Staphylococcus xylosus (7), S. capitis (6), S. chromogenes (4), S. sciuri (3), S. auricularis (2), S. lentus (2), S. hyicus (2), Streptococcus suis (2) and Pseudomonas argentinensis (2). Sixteen other isolates were identified to species level. A molecular method using 16S rRNA sequencing was used to confirm/identify 22 isolates. Salmonella or campylobacters were not isolated from rectal swabs. E. coli and S. felis/simulans together constituted 50% of isolates from vagina. S. felis/simulans was the most common species from culture positive ear and eye samples. P. multocida was isolated from 15% of mouth samples. Coagulase-negative staphylococci were the most common isolates from nose and wound swabs. Staphylococcus aureus, or S. intemedius/S. pseudintermedius were not isolated from any sample. Antimicrobial drug resistance was minimal, most isolates being susceptible to all drugs tested against, including tetracycline.     

The identification and antimicrobial susceptibility of anaerobic bacteria from pneumonic cattle lungs.

One hundred and forty-four lungs obtained postmortem from cattle with pneumonia were cultured for anaerobic bacteria. Forty-five lungs yielded 73 anaerobic isolates belonging to 20 species. The number of isolations of anaerobes from acute fibrinous or suppurative bronchopneumonias (32.5%) was slightly lower than from similar chronic bronchopneumonias (36.5%). Anaerobes were not recovered from 15 lungs showing macroscopic changes not of bacterial origin, nor from 13 healthy lungs. The predominant genera isolated were Bacteroides, Peptococcus, Fusobacterium and Clostridium. The most common species were P. indolicus (15 isolates), B. asaccharolyticus (nine), F. necrophorum (six), C. perfringens (four) and B. fragilis (four). There was a significant correlation between the presence of Corynebacterium pyogenes (p less than 0.001) or Escherichia coli (p less than 0.01) and the presence of anaerobes in the lungs. The isolated anaerobic bacteria were generally susceptible to ampicillin, penicillin G, cefoxitin, cephalothin, clindamycin, chloramphenicol, erythromycin, tetracycline and metronidazole. The B. fragilis and C. perfringens isolates showed multiple antibiotic resistance, and five P. indolicus isolates were resistant to tetracycline.     

Pheno- and genotypic characterization of Pasteurella multocida isolated from cats,dogs and rabbits from Brazil

Pasteurella multocida is the causative agent of many diseases of economic importance in veterinary medicine and is characterized by high zoonotic potential. Pet animals can be infected and play a major role as carriers. This study aimed to characterize the genetic diversity of P. multocida isolated from dogs, cats and rabbits, and to evaluate their antimicrobial susceptibility profiles. A total of 620 animals were studied; 51 were positive for P. multocida and 92 strains were isolated. 60.9% of the strains belonged to the capsular type A, while the remaining were classified as non-typeable. The hgbA, ptfA, sodC, tadD and hsf2 genes were more frequent among the rabbit strains. Sulfonamides and cotrimoxazole presented the highest resistance rate, followed by erythromycin. PFGE clustered strains according to host species. Our results indicate that P. multocida from companion animals carry several virulence factors and are resistant to antimicrobials commonly used in human and veterinary medicine.     

In vitro and in vivo pathogenicity studies of Pasteurella multocida strains harbouring different ompA

Pasteurella multocida is a pathogenic, Gram-negative bacterium that is commonly found as normal flora in nasopharynx of variety of wild and domestic animals. Numerous virulence factors have been described for P. multocida isolates which include adherence and colonization factors, iron-regulated and acquisition proteins, extracellular enzymes such as neuraminidase, lipopolysaccharide (LPS), capsule and a variety of outer membrane proteins (Omp). OmpA has a significant role in stabilizing the cell envelope structure by providing physical linkage between the outer membrane & peptidoglycan. It has been shown to mediate P. multocida -host cells interaction via heparin and/or fibronectin binding and therefore act as an important invasive molecule which could determine the final outcome of initial infection. Comparative nucleotide sequence analysis of ompA gene of P. multocida has revealed that despite extensive genetic diversity in ompA of P. multocida, most sequences could be classified into two major allele classes namely ompA allele (I) and allele (II). The P. multocida recovered from nasal cavity of bovine and belonging to two ompA classes were tested for their differential virulence. In vitro pathogenicity studies on Madin Darby Bovine Kidney (MDBK) cell line employing adhesion and invasion assays indicated that P. multocida strain with ompA (I) is more invasive than P. multocida strain with ompA (II). In vivo studies in mice further reiterated that the isolates harbouring ompA(I) were comparatively more virulent to isolates harbouring ompA (II).     

Carboxyl terminus heterogeneity of type IV fimbrial subunit protein of Pasteurella multocida isolates

Pasteurella multocida, a Gram-negative bacterial pathogen, known to affect a wide range of domestic as well as wild animal and avian species throughout the world by causing either systemic or localized infections termed as ‘pasteurellosis’. P. multocida isolates are known to possess type IV fimbriae (pili) as one of the major virulence factors based on their role in adhesion to host surfaces and subsequent pathogenesis. In the present study, ptfA gene of Indian P. multocida isolates (n?=?8) originated from different animal (buffalo, sheep, goat, pig) and avian host species (chicken, turkey, duck, quail) were amplified, cloned, sequenced and compared with available ptfA/fimbrial protein sequences in GenBank/publications (n?=?22) to understand its variability with respect to geography/host/serogroup/disease specific patterns. Multiple sequence alignment revealed highly conserved N-terminus α-1 helix region and heterogeneous C-terminus (68–137 aa) comprised of β-strand regions (β1, β2, β3, β4) with conserved two pairs of cysteine residues. Interestingly, an existence of absolute homogeneity among the P. multocida isolates that caused haemorrhagic septicaemia in bovines and septicaemic pasteurellosis in sheep and goats was noticed. Pig isolates had 99.3 % homogeneity. On contrary, more diversity (35.8 %) was observed among isolates that caused fowl cholera in avians irrespective of identical capsular/somatic serogroup and similar host species. Phylogenetic analysis based on nucleotide sequences of ptfA gene revealed formation of mixed clusters with isolates representing different disease conditions as well as serogroups irrespective of country of origin which indicated the possible role of cross-species transmission among different animal/avian species. The study indicated highly conserved and host specific fimbriae among animal species than relatively divergent fimbriae among avian species.     

A test in vero cell monolayers for toxin production by strains of Pasteurella multocida isolated from pigs suspected of having atrophic rhinitis

Monolayers of Vero cells showed a morphological changes after exposure to supernatants of certain porcine Pasteurella multocida cultures. It appeared possible to screen Pasteurella multocida isolates for their ability to produce toxin and to cause atrophic rhinitis in pigs. A close correlation with the guinea pig skin test was demonstrated.     

Occurrence of anaerobic bacteria in diseases of the dog and cat.

A survey for anaerobic bacteria was conducted in 314 clinical specimens from dogs and cats. A total of 187 anaerobic isolates in pure and mixed culture were isolated from 111 of the specimens that contained anaerobic bacteria. Common isolated included Actinomyces (9.1%), Clostridium perfringens (19.3%), other Clostridium spp (11.2%), Peptostreptococcus anaerobius (7.5%), Bacteroides melaninogenicus (13.4%), other Bacteroides spp (17.6%), and Fusobacterium necrophorum (5.3%). Anaerobic bacteria were involved in serious lesions that often were life threatening to the animals. Antibiotic susceptibility data indicated that the lincomycin family, the penicillin family, chloramphenicol, and cephaloridine are preferred drugs for treatment of anaerobic infections. Data from the survey were used in formulation of a table to aid practitioners in clinical diagnosis of disease caused by anaerobes. Clostridium perfringens was isolated in large numbers from five of six dogs with a clinical diagnosis of canine hemorrhagic gastroenteritis and from one cat with hemorrhagic diarrhea. Experimental infections were induced in rats, using caine feces as inoculum. Induced lesions contained aerobic and anaerobic bacteria similar to those bacteria isolated in the clinical survey, indicating that feces may serve as a major source of these bacteria in clinical infections of the dog.     

Meningoencephalomyelitis in domestic cats: 3 cases of Pasteurella multocida infection and literature review

Neurologic diseases are common in domestic cats, and infectious agents are suspected to be the primary cause in 30–45% of cases. Among infectious etiologies, those of bacterial origin are only sporadically characterized in the literature, with few of these reports correlating gross and histologic findings with confirmatory bacteriologic identification. Here, we describe bacterial meningitis and meningoencephalomyelitis associated with Pasteurella multocida in 3 domestic cats. Purulent exudate expanding the cerebral meninges was grossly evident in 2 of the cases. In all 3 cases, histologic changes included multifocal suppurative-to-necrosuppurative meningitis and/or meningoencephalomyelitis of variable severity. Intralesional colonies of gram-negative, short rod-shaped to coccobacillary bacteria were evident histologically in only 1 case. P. multocida was confirmed by routine bacteriologic culture in all cases. Based on our cases, we hypothesize that the upper respiratory system serves as the main portal of entry for P. multocida, leading to invasion of the central nervous system and possible systemic hematogenous dissemination. A case series of meningoencephalomyelitis associated with P. multocida infection in cats has not been reported previously, to our knowledge. We also review briefly other causes of meningoencephalomyelitis in cats.     

Anaerobic microflora associated with the pars oesophagea of the pig.

In healthy pigs aged one to 35 days significant populations of microorganisms (5.5 to 6.9 log10 viable count cm-2 of the tissue) were found, by strict anaerobic techniques, to adhere to the pars oesophagea. The genera of anaerobes which were isolated included Actinomyces, Bifidobacterium, Clostridium, Lactobacillus, Peptostreptococcus, Streptococcus and Veillonella and facultative anaerobes included Escherichia, Klebsiella, Staphylococcus, Streptococcus and yeasts. The microbial population adhering to the pars oesophagea varied little from birth till after weaning and Lactobacillus, Clostridium and Eubacterium predominated. There were generally small numbers of facultatively anaerobic microorganisms in the pars oesophagea of healthy sucking or weaned pigs but large numbers of anaerobes, particularly Lactobacillus. In the pars oesophagea of sucking and weaned pigs with diarrhoea, large numbers of facultative anaerobes were frequent but Lactobacillus were also present in large numbers.     

Bovine respiratory disease: efficacy of different prophylactic treatments in veal calves and antimicrobial resistance of isolated Pasteurellaceae

The present study was conducted to evaluate the efficacy of two prophylactic antibiotic treatments against bovine respiratory disease (BRD) in veal calves. In addition, the antibiotic susceptibilities of isolated Pasteurellaceae were tested. The calves were treated either on the day of arrival by a single administration of tulathromycin (group A, n = 20), by a peroral administration of chlortetracycline, sulphadimidine, and tylosin (group B, n = 20) for seven consecutive days, or were not prophylactically treated (group C, n = 19). On the first day of clinically diagnosed BRD, transtracheal lavage samples were obtained prior to therapeutic treatment and were subsequently cultured. Pasteurellaceae isolates were tested for their susceptibility to 12 antimicrobial agents by the determination of the minimal inhibitory concentrations. During the first 56 d after arrival, different calves in group A and B suffered from one episode of clinically diagnosed BRD while calves of group C experienced two episodes. The average daily weight gain during the same period was significantly lower in group C (0.89 ± 0.04 kg/d) than in the two prophylactically treated groups (1.14 ± 0.05 and 1.15 ± 0.04 kg/d for group A and B, respectively). The improved performance of groups A and B in comparison to group C could be related to a lower incidence of respiratory disorders during the first days after arrival in the prophylactically treated animals. No differences in the clinical efficacy were seen between the two tested prophylactic treatments. The most prevalent bacterial pathogens isolated (n = 79) were Pasteurella multocida (23% of isolated pathogens), Mycoplasma bovis (18%), and Mannheimia varigena (16%). For the isolated Pasteurellaceae, a high resistance pattern was observed to tylosin (83% of the tested P. multocida and 88% of the Mannheimia spp. isolates resistant) and tilmicosin (56% of the tested P. multocida isolates non-sensitive).     

Aerobic bacteriological studies on the respiratory tracts of apparently healthy and pneumonic camels (<Emphasis Type="Italic">Camelus dromedaries</Emphasis>) in selected districts of Afar Region,Ethiopia

A cross-sectional study was conducted to isolate and identify bacterial species from the respiratory tract of apparently healthy and pneumonic camels in Asayita and Dubti woredas in the Afar Region, Ethiopia. From a total of 74 lung tissue and 74 tracheal swab samples Staphylococcus aureus, 16.3%, Streptococcus equi subsp. equi, 13.0%, and Pasteurella multocida, 10.9%, were dominant isolates from pneumonic lungs; Escherichia coli, 12.7%, Proteus species, 10.9%, and Klebsiella pneumoniae, 9.1%, were the majority in the normal lungs. The majority of the isolates colonized both anatomical sites investigated. There was a statistically significant association between the health status of the camels as well as the anatomical site studied with the isolation rates of the major respiratory pathogens (p?<?0.05). Furthermore, the isolates were susceptible to norfloxacin, streptomycin, and gentamicin but resistant to ampicillin and tetracycline on in vitro test. Further studies on the pathogenicity of the major isolates are recommended.