Mutational and acquired carbapenem resistance mechanisms in multidrug resistant Pseudomonas aeruginosa clinical isolates from Recife, Brazil

An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem- resistant Pseudomonas aeruginosa isolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosa isolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXYOprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and β-lactamase production were responsible for the multidrug resistance in the isolates analysed.

Novel point mutations in the ERG11 gene in clinical isolates of azole resistant Candida species

The azoles are the class of medications most commonly used to fight infections caused by Candida sp. Typically, resistance can be attributed to mutations in ERG11 gene (CYP51) which encodes the cytochrome P450 14α-demethylase, the primary target for the activity of azoles. The objective of this study was to identify mutations in the coding region of the ERG11 gene in clinical isolates of Candida known to be resistant to azoles. We identified three new synonymous mutations in the ERG11 gene in the isolates of Candida glabrata (C108G, C423T and A1581G) and two new nonsynonymous mutations in the isolates of Candida krusei - A497C (Y166S) and G1570A (G524R). The functional consequence of these nonsynonymous mutations was predicted using evolutionary conservation scores. The G524R mutation did not have effect on 14α-demethylase functionality, while the Y166S mutation was found to affect the enzyme. This observation suggests a possible link between the mutation and dose-dependent sensitivity to voriconazole in the clinical isolate of C. krusei. Although the presence of the Y166S in phenotype of reduced azole sensitivity observed in isolate C. krusei demands investigation, it might contribute to the search of new therapeutic agents against resistant Candida isolates.

Application of Lidocaine Spray for Tracheal Intubation in Neonates - A Clinical Trial Study

Background: Tracheal intubation is extremely distressing, painful, and may influence heart rate and blood pressure. Sedatives, analgesics, and muscle relaxants are not commonly used for intubation in neonates. Objectives: This study aimed to evaluate the effects of lidocaine spray as a non-intravenous drug before neonatal intubation on blood pressure, heart rate, oxygen saturation and time of intubation. Patients and Methods: In a randomized, controlled study each neonate was randomly assigned to one of the two study groups by staffs who were not involved in the infant's care. The allocation concealment was kept in an opaque sealed envelope, and the investigators, the patient care team, and the assessors were blinded to the treatment allocation. The selected setting was NICU unit of a teaching hospital in Ilam city, Iran and participants were 60 neonates with indication of tracheal intubation with gestational age >30 weeks. Patients in the treatment group received lidocaine spray and the placebo group received spray of normal saline prior to intubation. Main outcome measurements were the mean rates of blood pressure, heart rate, oxygen saturation, intubation time and lidocaine side effects were measured before and after intubation. Results: Totally 60 newborns including 31 boys and 29 girls were entered into the study (drug group n = 30; placebo group n = 30). Boy/girl ratio in treatment and placebo groups were 1.3 and 0.88, respectively. Mean age ± SD of participants was 34.1 ± 24.8 hours (treatment: 35.3 ± 25.7; placebo: 32.9 ± 24.3; P < 0.0001). Mean weight ± SD of neonates was 2012.5 ± 969 g. Application of lidocaine spray caused a significant reduction of mean intubation time among treatment group compared with placebo group (treatment: 15.03 ± 2.2 seconds; placebo: 18.3 ± 2.3 seconds; P < 0.0001). Mean blood pressure, heart rate and oxygen saturation rate, among neonates in treatment group was reduced after intubation compared with their relevant figures before intubation; however, their differences were not statistically significant except for mean oxygen saturation rate that was reduced significantly in placebo group. No side effects were observed during study. Conclusions: Though the current study revealed some promising results in the application of lidocaine spray during neonatal intubation without any considerable side effects; however, the current investigation could only be considered as a pilot study for further attempts in different locations with higher sample sizes and in different situations.