Genetic Transformation in Haemophilus parainfluenzae Clinical Isolates

Abstract

Haemophilus parainfluenzae isolates recovered from patients with respiratory diseases were studied for their ability to undergo genetic transformation by isogenic DNA. Two chromosomal markers, streptomycin resistance and nalidixic acid resistance, were tested for transformation efficiencies in H. parainfluenzae recipients from three biotypes. Most efficient in transformation was biotype II, followed by biotype I, while biotype III was nontransformable. Lack of transformation was not owing to poor donor activity of DNA, but to inability of the cells to develop competence. Strains that formed clumps in liquid media were nontransformable. Since the transformable biotype II is one of the prevalent biotypes world wide, one can speculate that DNA transformation probably plays a major role in the spread of drug resistance in H. parainfluenzae.

The sodA gene as a target for phylogenetic dissection of the genus Haemophilus and accurate identification of human clinical isolates

“…1), indicating that H. parainfluenzae, H. pittmaniae and the ''Haemophilus sensu stricto'' species might share an independent ancestor, as recently suggested by multilocus sequence analysis (Nørskov-Lauritsen et al, 2005). Alternatively, interspecific genetic recombination might have occurred between these naturally competent species (Nickel and Goodgal, 1964;Gromkova et al, 1998) encountered in the same ecologic niche, resulting in their apparent relatedness. Whether H. parainfluenzae and H. pittmaniae should be reassigned a new genus remains to be determined, taking into consideration the potential confusion such a change would generate in clinical practice.…”

Addiction of Hypertransformable Pneumococcal Isolates to Natural Transformation for In Vivo Fitness and Virulence

“…Similar variability in transformation frequency has also been reported in other naturally transformable bacteria, such as Actinobacillus actinomycetemcomitans (33), Haemophilus influenzae (34,35), Haemophilus parainfluenzae (36), Helicobacter pylori (37), Pseudomonas stutzeri (38), and Ralstonia solanacearum (39). However, the molecular basis and biological importance of the strain-to-strain variability in transformation frequency remain unclear in S. pneumoniae and other naturally transformable bacteria.…”

Natural Competence Rates Are Variable Among Xylella fastidiosa Strains and Homologous Recombination Occurs In Vitro Between Subspecies fastidiosa and multiplex

“…One key knowledge gap is related to the variability of natural competence among strains, as previous studies were based on a few closely related strains belonging to the same subsp., namely, fastidiosa (Kandel et al 2016;Almeida 2011, 2014;Kung et al 2013). Since both genotypic and phenotypic differences have been described in X. fastidiosa strains (Antonova and Hammer 2015;Coletta-Filho et al 2017;Oliver et al 2014Oliver et al , 2015Parker et al 2012;Scally et al 2005), their natural competence abilities could differ, as is the case reported in other naturally competent bacteria (Bossé et al 2009;Coupat et al 2008;Evans and Rozen 2013;Fujise et al 2004;Gromkova et al 1998;Maughan and Redfield 2009;Sikorski et al 2002). Moreover, although IHR has been detected by MLST studies and was hypothesized to lead to plant host shift (Nunney et al 2012;2014a and2014c), there is still no experimental evidence demonstrating the generation of recombinants by mixing two different subspecies.…”