Molecular Characterization of Mycoplasma gallisepticum Isolates from Jordan

Abstract

Two groups of Mycoplasma gallisepticum (MG) isolates (n = 24) from Jordan were analyzed by molecular methods and compared with other Middle Eastern isolates, related international isolates, and reference strains. The first group (n = 19) was isolated from July 2004 to January 2005 (isolation period A), and the newer group (n = 5) from June 2007 to April 2008 (isolation period B). The groups of isolates are from chicken flocks from northern Jordan, but are not from the same farms. None of the flocks were vaccinated for MG. Random amplified polymorphic DNA analysis, targeted sequencing of the partial MG cytadhesin 2 (mgc2), and the MG 16S-23S rRNA intergenic spacer region (IGSR) divided the Jordanian isolates into two groups. All of the 19 isolates from time period A, in addition to two isolates from time period B, were indistinguishable from the F strain. Three of five isolates from time period B were characterized as wild types and were indistinguishable from each other. The wild-type field strain was readily distinguished from the F strain. It was 91% and 96.4% similar to the F strain based on Clustal-W alignments of sequences of mgc2 and IGSR, respectively. Sequence similarity of mgc2 gene of the Jordan wild-type strain to isolates from Israel and Egypt ranged from 96.5% to 100%, whereas for IGSR it was 99.4%-100%. We theorize that the F-strain live MG vaccine, commonly used in Jordan prior to 2007, was transmitted to nonvaccinated poultry in the region and was a predominant genotype during time period A.

The development and application of aMycoplasma gallisepticumsequence database

“…The use of single nucleotide changes to differentiate strains is supported by the correlation of these differences with RAPD results, and by the demonstrated sequence stability of the genetic targets (Ferguson et al, 2005;Raviv et al, 2007;Gharaibeh et al, 2011). It is possible, however, that certain single nucleotide changes of particular targets do not result in strain differences.…”

Molecular typing of Indian Mycoplasma gallisepticum isolates

“…Despite the wide prevalence of this pathogen in India, the phylogenetic clustering of the Indian isolates was not known. Genetic analysis by targeted sequencing of genes such as mgc2 is a great tool for studying the genetic diversity of prevalent M. gallisepticum isolates (Ghorashi et al 2010;Gharaibeh et al 2011), identification of new strains, and to compare the Indian field isolates with strains from other countries. Strain differentiation is also important for the control of M. gallisepticum, as it can help to rapidly identify, trace and devise targeted control strategies (Ferguson et al 2005).Sequence analysis of surface-protein genes have been shown to provide better strain differentiation than other molecular typing methods like random amplified polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP) and amplified fragment length polymorphism (AFLP) with high reproducibility (Ferguson et al 2005).…”

Identification of Strain-Specific Sequences That Distinguish a Mycoplasma gallisepticum Vaccine Strain from Field Isolates

“…These vaccine strains exhibit various degrees of effectiveness and safety (9–11), and there is evidence that some of these M. gallisepticum vaccine strains can revert to virulence (9, 12, 13). Currently, the genetic basis behind the attenuation of the vaccine strains is not well understood.…”

“…It has also been difficult to differentiate vaccine M. gallisepticum strains from some field isolates (12, 13, 23). This is important in order to differentiate M.…”