Molecular detection of genes related to biofilm formation in multidrug-resistant Acinetobacter baumannii isolated from clinical settings

Abstract

Acinetobacter baumannii is a Gram-negative bacteria associated with hospital-acquired infections. Definitely, antimicrobial resistance and biofilm formation capabilities of clinical isolates have threading potential to persistence in the hospital environment and colonization on medical equipment. Twenty-seven multidrug-resistant clinical isolates were selected from a collection of A. baumannii samples isolated from clinical settings. PCR assays showed the frequencies of genes related to biofilm formation: ompA (100%), bap (30%) and blaPER-1 (44%). Polyclonal antibodies against recombinant AbOmpA8-346 and Bap1-487 proteins were obtained by the mouse immunization method. Western blotting revealed all isolates expressed AbOmpA and only eight isolates were positive for Bap factor. Two strains that had their bap gene disrupted with ISAba125 did not express Bap protein. Our findings showed that all double-negative bap/blaPER-1 isolates were recovered from the bloodstream and had low biofilm formation capabilities, and mostly belonged to type D wrinkled colony morphology. However, clinical isolates extracted from the throats of patients were blaPER-1-positive and had a great capacity to form biofilm, and also mostly belonged to type C wrinkled colony morphology.

Immunological evaluation of OMV(PagL)+Bap(1-487aa) and AbOmpA(8-346aa)+Bap(1-487aa) as vaccine candidates against Acinetobacter baumannii sepsis infection

“…Overall the AbOmpA is a conserved protein, but there are minor amino acids variations in four extracellular loops of beta-barrel domain of this protein (data have not been published). In our previous study the presence and expression of AbOmpA protein were confirmed in all MDR A. baumannii clinical isolates (Badmasti et al, 2015b). In this study data showed the ratio of IgG1/IgG2c in AbOmpA vaccination was 0.95.…”

“…For the Bap factor we used one conserved immunodominant region from four regions based on Rahbar et al study (Rahbar et al, 2010). Our previous study revealed the frequency of Bap factor in MDR A. baumannii clinical isolates is 30% (Badmasti et al, 2015b). Al though this factor has low frequency but for covering all pathogenic isolates and satisfied protection we added it in combination vaccines.…”

Outer membrane protein A (OmpA) as a potential therapeutic target for Acinetobacter baumannii infection

“…According to the statistics of National Institutes of Health and the Center for Disease and Prevention, 65-80% human infections were caused by biofilm-forming bacteria [58]. Based on the multi-functional characteristics of biofilm formation, a series of genes associated with bacterial adhesion and biofilm formation were identified, such as AbOmpA, beta-lactamase PER-1 (blaPER-1) and biofilm-associated protein (Bap) [59]. Indeed, the OmpA of A. baumannii ATCC19606 plays a dominant role in forming stable biofilm on plastic surface (Fig.…”

Clinical Isolates of Acinetobacter baumannii From Tehran Hospitals: Pulsed-field Gel Electrophoresis Characterization, Clonal Lineages, Antibiotic Susceptibility, and Biofilm-forming Ability

“…Biofilm formation was quantified by the microtiter plate assay method as described previously (15). Briefly, A. baumannii species were grown overnight in trypticase soy broth (TSB) (Merck, Germany) with 0.25% glucose at 37°C.…”