Biofilm formation in clinical isolates of nosocomial Acinetobacter baumannii and its relationship with multidrug resistance

AbstractObjectiveTo check biofilm formation by Acinetobacter baumannii (A. baumannii) clinical isolates and show their susceptibility to different antibiotics and investigate a possible link between establishment of biofilm and multidrug resistance.MethodsThis study was performed on clinical samples collected from patients with nosocomial infections in three hospitals of Tehran. Samples were initially screened by culture and biochemical tests for the presence of different species of Acinetobacter. Identifications were further confirmed by PCR assays. Their susceptibilities to 11 antibiotics of different classes were determined by disc diffusion method according to Clinical and Laboratory Standards Institute guidelines. The ability to produce biofilm was investigated using methods: culture on Congo red agar, microtiter plate, and test tube method.ResultsFrom the overall clinical samples, 156 specimens were confirmed to contain A. baumannii. The bacteria were highly resistant to most antibiotics except polymyxin B. Of these isolates, 10.26% were able to produce biofilms as shown on Congo red agar. However, the percentage of bacteria with positive biofilm in test tube, standard microtiter plate, and modified microtiter plate assays were 48.72%, 66.66%, and 73.72%, respectively. At least 92% of the biofilm forming isolates were multidrug resistant.ConclusionsSince most of the multidrug resistant strains produce biofilm, it seems necessary to provide continuous monitoring and determination of antibiotic susceptibility of clinical A. baumannii. This would help to select the most appropriate antibiotic for treatment

Study of drug resistance and ompA gene existence in clinical Acinetobacter baumannii isolates

Background and Aim: Acinetobacter baumannii is one of the most important multi drug-resistant species associated with nosocomial infections. Several factors involve in resistance to drug and its pathogenicity. Of these factors, OmpA protein plays a crucial role. Therefore, the aim of current research was to assess resistance to drug and also ompA gene existence in A. baumannii isolated from clinical sources. Materials and Methods: Firstly, clinical samples were collected from Imam Khomeini, Milad and Motahari Hospitals during 2015-2016 years and the final confirmation were done by using biochemical methods. Afterwards, susceptibilities to antibiotics of different classes were determined by disc diffusion method and presence of ompA gene was checked by using PCR method and verified by sequencing. Results: The results show that of 650 clinical samples, 156 (24%) of isolates were formed of A. baumannii and mostly showed resistance to different classes of antibiotics. 92.95% of isolates were multi drug resistance (MDR) and finally 86.53% were extremely drug resistance (XDR). All of them contained ompA gene. Conclusions: Existence of multi drug resistance in most isolates as well as presence of ompA in all samples can cause bacterial virulence and drug resistance. It seems essential to provide continuous monitoring and determination of antibiotic susceptibility of clinical A. baumannii, decrease the moral and material damage caused by the bacteria

Impact of Side-Branch Flow in Coronary Bifurcation Intervention

Background: The optimal strategy in percutaneous coronary intervention (PCI) for coronary artery bifurcation lesions has yet to be agreed upon. We compared a strategy for stenting the main vessel to provide a complete perfusion flow in the side branch, namely thrombolysis in myocardial infarction (TIMI) - III, with a strategy for intervention in both the main vessel and the side branch (MV + SB). Methods: This retrospective study utilized data on 258 consecutive patients with bifurcation lesions scheduled for PCI at Tehran Heart Center between March 2003 and March 2008. The patients were followed up for 12 months, and the primary end point was a major adverse cardiac event (MACE), i.e. cardiac death, myocardial infarction, target-vessel revascularization, and target-lesion revascularization during the 12-month follow-up period. Results: A total of 52.7% of the patients underwent PCI on the main vessel of the bifurcation lesions (MV group) and 47.3% with a similar lesion type received a percutaneous intervention on both the main vessel and the side branch (MV + SB group). The total rate of MACE during the follow-up was 4.3% (11 patients); the rate was not significantly different between the MV and MV + SB groups (3.7% vs. 4.9%, respectively; p value = 0.622). Conclusion: There was no association between MACE in performing a simple or complex interventional strategy to treat coronary bifurcation lesions when drawing the TIMI- III flow as a goal in a simple technique