Emergence of Rifampicin, Tigecycline, and Colistin-ResistantAcinetobacter baumanniiin Iran; Spreading of MDR Strains of Novel International Clone Variants

Abstract

Multidrug-resistant Acinetobacter baumannii infections are serious challenges for clinicians because of A. baumannii propensity to acquire resistance to a wide spectrum of antimicrobial agents. In this study, 91 A. baumannii isolates from patients in tertiary intensive care units of three university hospitals in the north, central, and south of Iran were selected and tested for susceptibility to 22 antimicrobials; amplified restriction fragment polymorphism and multiplex polymerase chain reaction methods were used to determine genetic relationships and International Clone (IC) of A. baumannii isolates, respectively. Twenty-four genotypes were identified in A. baumannii isolates. About 91.2% of isolates categorized into 4 distinct clusters; one was more heterogeneous and observed across the three locations. A considerable number of the isolates (27.5%) belonged to the novel IC variant, sequence group 7 (SG7), which was geographically widespread in three locations. The drug resistance pattern showed that 14.2%, 20%, and 77% of the A. baumannii isolates were resistant to colistin, tigecycline, and rifampicin, respectively. Nine percent of isolates (8) showed simultaneous resistance to colistin, rifampicin, and tigecycline. Interestingly, all of them were susceptible to ampicillin-sulbactam and/or tobramycin. According to our results, SG7 could be considered as a pan-Iranian clone.

Identification and Isolation of Insertion Sequences, in Carbapenem Resistant Clinical Isolates of Acinetobacter baumannii from Tehran Hospitals

“…These results are in accordance with those of other studies (19,20,24,25). Unfortunately, the resistance of A. baumannii was not only to β -lactams including penicillin, 3rd generation cephalosporin, and carbapenems, but also to other drug divisions, including aminoglycosides and fluoroquinolones (21).…”

Increasing Trend of Imipenem-Resistance Among Acinetobacter baumannii Isolated From Hospital Acquired Pneumonia in Northeast of Iran

“…World health organization (WHO) declared that Multidrug resistance (MDR) strains of Acinetobacter baumannii are a significant threat worldwide. In total, many studies have shown that the prevalence of MDR strains of A. baumannii has reached an alarming statue all over the world (9), including Iran (10,11). Developing countries such as Iran have serious problems in treating the infections resulted from MDR strains.…”

Resistência à Colistina em isolados de hemoculturas de recém-nascidos admitidos em um hospital escola

“…35 demonstraram que todos os isolados foram resistentes ao ceftriaxona e cefepime, e relataram 4,9% de isolados resistentes ao imipenem e à colistina simultaneamente, porém todos sensíveis à tigeciclina. Ainda estes pesquisadores verificaram resistência a rifampicina em 77% dos isolados 35 .…”

“…35 demonstraram que todos os isolados foram resistentes ao ceftriaxona e cefepime, e relataram 4,9% de isolados resistentes ao imipenem e à colistina simultaneamente, porém todos sensíveis à tigeciclina. Ainda estes pesquisadores verificaram resistência a rifampicina em 77% dos isolados 35 . Uma pesquisa realizada com 60 isolados de A. baumannii coletados de pacientes e do ambiente em um hospital do Rio de Janeiro, apresentaram resistência igual ou superior a 80% para piperacilina/tazobactam, cefotaxima, ciprofloxacino, cefepime, imipenem e meropenem; e 68% de resistência para polimixina B, sendo que a resistência a colistina não foi relatada 13 .…”

“…Ainda, relataram que a idade prevalente dos pacientes foi entre 41 a 69 anos (77,77%) 16 . Bahador et al (2013)35 nos isolados com resistência simultânea à colistina, rifampicina e tigeciclina, demonstraram que a prevalência foi nos espécimes do trato respiratório (75%; 6/8), seguido de um isolado…”