Avian Strains Of Pasteurella Multocida Research Articles

Genetic diversity of different avian strains of Pasteurella multocida recovered during four outbreaks in India

Pasteurella multocida causes fowl cholera in avian species and type A is predominantly reported from outbreaks of fowl cholera. Biochemical, serological, and molecular methods are employed for its diagnosis and typing. Utilizing rapid molecular tools like repetitive extragenic palindromic (REP) PCR and enterobacterial repetitive intergenic consensus (ERIC) PCR, P. multocida isolates from four outbreaks (three from Chennai and one from Ahmadabad, India) were characterized and typed to determine their relationships. A total of 36 isolates were recovered from the outbreaks, including one isolate from a parakeet, which was also subjected to characterization by conventional and molecular analysis. All of the isolates were found to be capsular type A based on PCR assay capsular typing. ERIC- and REP-PCR showed differences in the banding patterns among different outbreak isolates, and also among the geographical regions. Differences were also noticed among different host species, as the banding pattern in the ERIC- and REP-PCR differed; the analysis of results also revealed the same. All of the isolates were found to be sensitive to enrofloxacin and cefotaxime among the antibiotics used in the study. It was found that different strains might have been involved in the different outbreaks reported in the study. The results show that molecular typing methods like ERIC- and REP-PCR are useful epidemiological tools for classifying the strains.

Draft Genome Sequences of Two Virulent Serotypes of Avian Pasteurella multocida.

Here we report the draft genome sequences of two virulent avian strains of Pasteurella multocida. Comparative analyses of these genomes were done with the published genome sequence of avirulent P. multocida strain Pm70.

Molecular Epidemiologic Investigation of Polish Avian Pasteurella multocida Strains Isolated from Fowl Cholera Outbreaks Showing Restricted Geographical and Host-Specific Distribution

Molecular Epidemiologic Investigation of Polish Avian Pasteurella multocida Strains Isolated from Fowl Cholera Outbreaks Showing Restricted Geographical and Host-Specific Distribution

Molecular Epidemiologic Investigation of Polish Avian Pasteurella multocida Strains Isolated from Fowl Cholera Outbreaks Showing Restricted Geographical and Host-Specific Distribution

Molecular epidemiologic analyses of the 42 clinical isolates of Pasteurella multocida from various avian hosts (geese, ducks, turkeys, and laying hens) in Poland from 2001 to 2011, including a single reference strain, were performed by enterobacterial repetitive intergenic consensus (ERIC)-PCR, single primer PCR, and repetitive extragenic palindromic (REP)-PCR. Forty-two isolates were identified as P. multocida (serotype A). The majority of P. multocida strains were obtained from waterfowl clustered within one genotype, and they were not consistent with the genotypes obtained from the turkey strains. Pasteurella multocida showed genetic homogeneity between the host species, especially when isolated on the same farm. Some of the clones also were characteristic to the particular farm. The strains obtained in different regions represent distinct molecular patterns. The present findings demonstrate that some clones of P. multocida are restricted in geographical and host distribution. In addition, this study suggests that ERIC-PCR, single primer PCR, and REP-PCR are suitable techniques for studying the host adaptation of P. multocida and the epidemiology of fowl cholera.

Characterisation and comparison of avian Pasteurella multocida strains by conventional and ERIC-PCR assays

Sixty-one avian strains of Pasteurella multocida were characterised and compared by biochemical tests, capsular PCR typing and ERIC-PCR. The strains were recovered from various avian species (goose, duck, Muscovy duck, turkey, chicken and pheasant) and represented different geographic locations in Hungary. Forty-two strains (69%) were identified as P. multocida subsp. multocida and 19 strains (31%) as P. multocida subsp. septica. The strains were grouped into 7 different biovars (1, 2, 3, 4, 5, 6 and 7). The most prevalent biovars were 1 (25%), 3 (21%) and 6 (21%). Most of the duck isolates (90%) belonged to biovar 1 or 6. The most frequent capsular type was A (93.5%). Type F represented only a small number (6.5%) of the strains. Other capsular types were not identified. From the 61 isolates 24 different fingerprint patterns were generated by ERIC-PCR assay. Based on cluster analysis the strains could be grouped into four larger and four mini-clusters that showed considerable correlation with the geographical origin and the host species. The results indicate that ERIC-PCR may be a suitable technique for studying the host adaptation of P. multocida and the epidemiology of fowl cholera.

Characterization of avian strains of Pasteurella multocida by restriction endonuclease and amplified fragment length polymorphism

Avian strains of Pasteurella multocida were typed by employing restriction endonuclease analysis (REA) and single enzyme-amplified fragment length polymorphism (AFLP) to evaluate their applicability for epidemiological studies of fowl cholera outbreaks. A total of 72 strains isolated from different avian species (chicken, duck, turkey, quail and goose) belonging to various geographical regions of India were characterized. REA using two different enzymes HhaI and HpaII produced 9 and 18 clusters respectively, whereas Single enzyme-AFLP recognized 32 patterns out of 72 strains typed. The study indicated that REA using HpaII is a simple and resource efficient method, however, further typing with more stringent and rapid method like Single enzyme-AFLP, could drastically enhance investigation in epidemiological studies of fowl cholera outbreaks.

Identification of avian strains of Pasteurella multocida in India by conventional and PCR assays

The prevalence of capsular and somatic serotypes were studied among 123 Pasteurella multocida strains isolated from chickens ( n = 94), ducks (22), quails (4), turkeys (2) and geese (1) from different geographical regions of India. All strains exhibited similar cultural and morphological characteristics. Ninety-two of the isolates belonged to serotype A:1, the most prevalent serotype, with serotypes A:3, A:1,3, D:3 and F:3 having two isolates each. Only one isolate was positive for serotypes A:4 and D:1. Twenty isolates were untyped. A multiplex capsular PCR assay generated amplicons of sizes ∼460, ∼1044, ∼657 and ∼854 bp in 106 isolates identified as capsular serotype-A, 15 in serotype D and two in serotype F. Capsular types B and E were not detected in any of the avian isolates studied. The present findings suggest that a multiplex capsular PCR assay may be suitable for the rapid initial identification serotypes P. multocida during epidemiological studies of fowl cholera.

Antibiotic Sensitivity Patterns among Indian Strains of Avian Pasteurella multocida

An investigation was carried out to study the antibiotic sensitivity of avian strains of Pasteurella multocida and to select an effective antimicrobial agent for control of avian pasteurellosis in India. A total of 123 strains of P. multocida recently isolated from different avian species (chicken, duck, turkey, quail, and goose), from different regions of India were subjected to antibiotic sensitivity tests using 20 different antibiotics. Absolute resistance was observed against sulfadiazine. The studies indicated that the strains were most sensitive to chloramphenicol (73.98%), followed by enrofloxacin (71.54%), lincomycin (64.23%), norfloxacin (61.79%) and doxycycline-HCl (56.91%). The majority of the strains were found to exhibit intermediate sensitivity. Chloramphenicol was selected and suggested for treatment. Antibiogram studies also revealed the emergence of multidrug-resistant strains of P. multocida among Indian poultry.

Diversity of avian Pasteurella multocida strains based on capsular PCR typing and variation of the OmpA and OmpH outer membrane proteins

One hundred avian Pasteurella multocida isolates recovered from cases of fowl cholera and related infections in England and Wales over a 13-year period were characterised by capsular PCR typing and analysis of outer membrane protein (OMP) profiles. Sixty-eight percent of the strains were of capsular type A, 14% were type F, 5% were type D, 4% were type B and 9% were untypable. Nineteen distinct OMP profiles (OMP-types) were identified based mainly on molecular mass heterogeneity of the heat-modifiable (OmpA) and porin (OmpH) proteins. Fifty-six percent of the isolates were represented by 15 OMP-types, whereas 44% of the isolates were associated with four OMP-types. The extensive molecular mass heterogeneity of the OmpA and OmpH proteins supports previous findings that avian P. multocida strains are very diverse. Furthermore, the isolates studied were associated with different clinical symptoms and were recovered from a wide range of lesions and tissues. The high degree of strain diversity together with the wide variety of clinical symptoms suggest that certain avian strains of P. multocida are opportunistic pathogens of relatively low virulence. Strains of capsular types B, D and F, as well as the untypable isolates, were associated exclusively with specific OMP-types and represent distinct and widely disseminated clonal groups. These observations support the view that avian strains of P. multocida have a clonal population structure. Based on previous studies, the molecular mass heterogeneity of the OmpA and OmpH proteins might provide a selective advantage to P. multocida by generating antigenic variation.

Molecular analysis of a cryptic plasmid isolated from avian strains of Pasteurella multocida

Twelve small plasmids isolated from avian strains of Pasteurella multocida were examined by restriction enzyme mapping, cross-hybridization, and minicell analysis. These plasmids contained sites for several commonly used restriction enzymes and ranged in size from 3.4 to 3.8 kilobases. Restriction enzyme maps of the 12 plasmids were similar and divided the plasmids into 3 families, designated pFS1, pFS2, and pFS4. Restriction fragments of pFS1 DNA isolated from strain X-73 were used to probe AvaI/ HindIII/ EcoRV digests of pFS2 and pFS4 DNA. The results of these hybridization experiments demonstrated that the plasmids found in all three families shared extensive regions of homology and may have originated from a common ancestor. Escherichia coli minicells containing recombinant plasmid constructs bearing fragments of pFS1 expressed two pFS1-specific peptides, 12.5 and 28 kilodaltons in size, suggesting that some P. multocida plasmid-encoded proteins can be expressed in E. coli. These results indicate that pFS may be useful as a genetic tool for moving DNA into and out of P. multocida, since it is small, contains common restriction sites, and encodes at least two genes that are recognized and expressed in E. coli.

Factors affecting endotoxin release from the cell surface of avian strains of Pasteurella multocida

Two avian strains of Pasteurella multocida, a vaccine strain and a virulent field isolate, were investigated to determine their propensity to release endotoxin from the cell surface. Both organisms released comparable amounts of endotoxin when plasma complement proteins were present, however the virulent strain did so without the loss of viability that occurred in the vaccine strain. Blocking complement activity decreased the ability of plasma to elicit endotoxin release from the bacteria. When the cells were treated with divalent metal chelators such as trans-1,2-diaminocyclohexane-N,N,N 1,N 1-tetraacetic acid (CDTA), more endotoxin was released from the vaccine strain than from the virulent isolate. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of purified lipopolysaccharide (LPS) from both strains revealed virtually identical patterns. Both had patterns considered typical of rough LPS. Challenge studies in 8 week old turkeys showed that the field strain induced endotoxemia of longer duration than the vaccine strain and produced greater mortality.

Cell surface characteristics and virulence in mice of Pasteurella multocida

The virulence of three avian strains of Pasteurella multocida was evaluated in mice. Strains P-1059I (serotype A:3) and its uncapsulated variant P-1059B and strain 2723 (serotype A:16) were compared. Capsular material thickness after polycationic ferritin labelling of dextrose starch agar (DSA)-grown P. multocida was shown to vary with the strain and was not always related to virulence. Addition of alpha,alpha' bipyridyl (BIP) (160 microM) to the culture medium did not affect capsule production but increased virulence of strains P-1059B and 2723. None of the strains tested showed dermonecrotic activity. Using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), outer membrane protein (OMP) profiles indicated for strains P-1059I and P-1059B three proteins of 30, 35, and 38 KDa with the 30 KDa protein being the major one. Strain 2723 showed the same OMP profile but the 38 KDa protein was the major one. DSA + BIP-grown strains showed the same OMP profiles. Whole cell profiles were similar for all strains tested. However, addition of BIP to the culture media increased the virulence of strains P-1059B and 2723 and for all strains a 39 KDa protein was induced by the iron chelator. The results indicate that encapsulation may be important for virulence, but other surface components such as OMPs may be required as well.

A survey of potential virulence markers from avian strains of Pasteurella multocida

Twenty-four isolates of Pasteurella multocida from clinical cases of fowl cholera and the Clemson University of vaccine strain were surveyed for the presence of potential virulence markers. Membrane proteins, enzymatic activity of the membrane proteins, and carbohydrate fermentation patterns were also determined to demonstrate phenotypic relationship within the groups. Few differences were found in these phenotypic characteristics among the isolates. Almost all the organisms produced siderophore and were hemolytic on turkey red blood cells. No extracellular enzyme or bacteriocin activity was detected and little antibiotic resistance was found. However, many organisms contained plasmids and demonstrated some degree of resistance to complement. Both characteristics were correlative markers in Pasteurella multocida isolated from birds with fowl cholera.

Serum resistance is correlated with encapsulation of avian strains of Pasteurella multocida

Encapsulated avian strains of Pasteurella multocida possessing an A-type capsule were shown to be resistant to the bactericidal action of turkey serum, whereas unencapsulated variants as well as other unencapsulated strains were not. Removal of the capsule from serum-resistant strain P1059-1 resulted in this strain becoming susceptible to the bactericidal effects of turkey serum. Since complement was consumed when encapsulated or unencapsulated strain P1059-1 was incubated in turkey serum, we conclude that the capsule acts to shield the outer membrane rather than prohibiting the generation of an effective membrane attack complex.

Capsular Groups of Pasteurella multocida Isolated from Avian Hosts

Avian strains of Pasteurella multocida representing a variety of host types, geographic locations, and somatic serotypes were examined to provide information on the distribution of capsular serogroups. Of the 246 strains studied, 166 were capsular group A, 4 were group B, 4 were group D, and 14 were group F; 58 strains were non-encapsulated and consequently not serogroupable. This is the first report of serogroup B P. multocida from avian hosts in the United States. The 188 serogroupable strains represented 12 variations in somatic serotypes and were isolated from 11 types of avian hosts representing 25 states of the United States, Bangladesh, Singapore, and Canada.

Studies on Fowl Cholera. II. The Correlation between Biochemic Classification and the Serologic and Immunologic Nature of Avian Pasteurella Multocida Strains

Rosenbusch and Merchant (7) demonstrated that the fermentative action of PasteureUlla multocida strains on xylose, arabinose, and dulcitol was correlated with the results of tube agglutination tests. Roberts (6) noted that the fermentative action of strains on these carbohydrates was correlated with immunologic type as determined by passive immunization of mice. This study was made to determine how the biochemic groups of avian P. multocida strains as based on fermentative action on xylose, arabinose, and dulcitol was related to their serologic and immunologic nature. Strains selected for the study were classified biochemically according to fermentative reactions as group I, II, or III. A rapid plate agglutination test was used in the serologic study. The immunologic study was made by active immunization of fowls.