Detection of Extended-Spectrum ß-Lactamases among Acinetobacter Baumannii Isolated from Hospitals of Qazvin, Iran.

BACKGROUND: Acinetobacter baumannii is a major contributor to nosocomial infections. Extended-spectrum ß-lactamase (ESBL)-producing A. baumannii is spreading worldwide. We aimed to determine the frequency of ESBL-encoding genes in clinical isolates of A. baumannii and to access their clonal relationship by repetitive extragenic palindromic-PCR (rep-PCR). METHODS: In this descriptive cross-sectional study, 203 isolates of A. baumannii were collected from Qazvin hospitals. The Identification of isolates was performed by standard laboratory methods. To verify ESBL production, all isolates were screened by disk agar diffusion and confirmed by the combined disk method. Subsequently, ESBL-encoding genes were detected by PCR and sequencing. Possible clonal association of ESBL-producing isolates was evaluated using rep-PCR. RESULTS: Two hundred (98.5%) isolates showed reduced susceptibility to one of the antibiotics used in the ESBL screening test, of which 127 isolates (62.6%) produced ESBL. PCR results showed blaOXA-1 (20.5%) was the most prevalent gene followed by blaTEM-1 (20%), blaGES-1 (15.7%), blaCTX-M-15 (7.9%), and blaPER-1 (1.6%). Rep-PCR results revealed that ESBL-producing isolates belonged to clones A (85%), B (13.4%), and C (1.6%). CONCLUSION: Our study showed the significant presence of blaOXA-1, blaTEM-1, blaGES-1, blaCTX-M-15, and blaPER-1 genes in ESBL-producing A. baumannii isolates in the studied hospitals. This is the first report on the emergence of blaOXA-1 gene in these isolates in Iran. The use of comprehensive antimicrobial treatment guidelines based on laboratory data and appropriate infection control interventions are essential.

The Emergence of Quaternary Ammonium Compounds Resistance in Escherichia coli Isolated from Hospitals of Qazvin, Iran.

INTRODUCTION: Escherichia coli is one of the most important agents involved in healthcare-associated infection, and resistance to quantum ammonium compounds (QACs) has become a major challenge for infection control practitioners. The aim of the current study was to determine the frequency of qacE and qacEΔ1 genes in E. coli isolated from hospitalized patients in Qazvin, Iran. MATERIAL AND METHODS: In the current cross-sectional study, 102 E. coli were collected from hospitals of Qazvin. All bacterial isolates were identified using standard laboratory methods and the antimicrobial susceptibility was evaluated by Kirby-Baer test. The presence of qacE and qacEΔ1 genes was investigated using polymerase chain reaction (PCR) technique. RESULTS: In this study, 65 (63.7%) isolates showed a multidrug resistance (MDR) pattern which was resistant to at least three classes of antimicrobials including ß-lactams, aminoglycosides, and fluoroquinolones. The highest rates of resistance were observed against cefotaxime (75.5%) and nalidixic acid (66.7%). The PCR showed that 5 (4.9%) isolates harbored qacE gene, 62 (60.8%) isolates qacEΔ1, and 10 (9.8%) isolates carried both genes, simultaneously. There was a significant relationship between the QACs resistance and MDR pattern (P=0.03). CONCLUSION: This study indicated a significant resistance rate against disinfectant compounds in the studied hospitals. However, more attention should be paid to this critical issue in the infection control committees of the hospitals.

Plasmid-Mediated Quinolone Resistance in Pseudomonas aeruginosa Isolated from Burn Patients in Tehran, Iran.

INTRODUCTION: Plasmid-induced quinolone resistance has raised a great concern in the treatment of serious infections worldwide. The aims of this study were to determine the antibiotic susceptibility, the frequency of qepA, aac(6')-Ib and qnr genes by PCR and sequencing, and typing of the resistant isolates using repetitive extragenic palindromic sequence-based PCR (REPPCR) in Pseudomonas aeruginosa isolated from burn wound infections. METHODS: In the current cross-sectional study, 149 P. aeruginosa were isolated from the burn wound samples of patients admitted to Motahari hospital in Tehran, Iran, from February to December 2016. The bacterial isolates were identified using standard laboratory methods and their antibiotic susceptibility to quinolones was evaluated using the standard Kirby-Bauer method, according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The presence of aac(6')-Ib, qepA, qnrA, qnrB4, qnrB and qnrS genes was assessed using PCR and sequencing methods and clonal relationship of the resistant isolates was evaluated using REP-PCR method. RESULTS: All (100%) isolates showed complete resistance to used quinolone compounds in this study. The qnr and qepA genes were not found, but all (100%) isolates were positive for the presence of aac(6')-Ib gene and the sequencing revealed that all (100%) belong to the aac(6')-Ib-cr variant. REP-PCR showed that the studied isolates belonged to three distinct clones of A (77.9%), B (18.1%), and C (4%). CONCLUSION: The findings of the present study indicated the presence of aac(6')-Ib-cr variant and lack of the contribution of qnr and qepA in the emergence of resistance to quinolones in P. aeruginosa isolated from burn patients. Considering the importance of clonal spread of these resistant isolates and their significant role in the development of clinical infections, especially in patients with burns, more attention should be paid to the prevention of the dissemination of these resistant isolates.