ABSTRACT
Background@#Acinetobacter baumannii is one of the most important hospital pathogenic bacteria that cause infectious diseases. The present study aimed to determine the frequency of carbapenem resistance genes in association with transposable elements and molecular typing of carbapenem-resistant A. baumannii bacteria collected from patients in Shiraz, Iran. @*Materials and Methods@#A total of 170 carbapenem-resistant A. baumannii isolates were obtained from different clinical specimens in two hospitals. The minimum inhibitory concentrations (MIC) of imipenem were determined and the prevalence of OXA Carbapenemases, Metalloβ-lactamases genes, insertion sequences (IS) elements, and transposons were evaluated by the polymerase chain reaction (PCR) method. Finally, molecular typing of the isolates was performed by the Enterobacterial Repetitive Intergenic Consensus-PCR method. @*Results@#The MICs ranged from 16 to 1,024 µg/mL for imipenem-resistant A. baumannii isolates. Out of the 170 carbapenem resistant A. baumannii isolates, bla OXA-24-like (94, 55.3%) followed by bla OXA-23-like (71, 41.7%) were predominant. In addition, A. baumannii isolates carried bla VIM (71, 41.7%), bla GES (32, 18.8%), bla SPM (4, 2.3%), and bla KPC (1, 0.6%). Moreover, ISAba1 (94.2%) and Tn2009 (39.2%) were the most frequent transposable elements. Furthermore, (71, 44.0%) and (161, 94.7%) of the ISAba1 of the isolates were associated with bla OXA-23 and bla OXA-51 genes, respectively. Besides (3, 1.7%), (1, 0.6%) and (5, 2.9%) of bla OXA-23 were associated with IS18, ISAba4, and ISAba2, respectively. Considering an 80.0% cut off, clusters and four singletons were detected. @*Conclusion@#According to the results, transposable elements played an important role in the development of resistance genes and resistance to carbapenems. The results also indicated carbapenem-resistant A. baumannii bacteria as a public health concern.
ABSTRACT
To measure bacterial contamination rates in blood culture specimens and distinguish sepsis from blood culture contamination in newborn hospitalized patients in a neonatal intensive care unit and to recognize the most commonly isolated bacteria. Blood samples of 578 neonates were collected and cultured throughout the year of study [March 2006 to February 2007]. Isolated bacteria were identified by traditional biochemical tests. Clinical criteria combined with laboratory data were used to differentiate the contaminated cultures from clinically significant cultures. Of the 578 neonatal blood culture samples, 78 [13.49%] were positive for bacteria, and 49 isolates [8.47%] were classified as contaminants. Pseudo-monas aeruginosa and Staphylococcus aureus were the most common isolates from true bacteremia, and Staphylococcus epidermidis and diphtheroids were the most common contaminants. The blood culture contamination rate in our studied neonatal intensive care unit was high. A variety of measures are recommended for reducing the rate of blood culture contamination to avoid undesirable outcomes associated with blood culture contamination