Co-Existence of Carbapenemase-Encoding Genes in Acinetobacter baumannii from Cancer Patients

Abstract

Introduction Acinetobacter baumannii is an opportunistic pathogen, which can acquire new resistance genes. Infections by carbapenem-resistant A. baumannii (CRAB) in cancer patients cause high mortality. Methods CRAB isolates from cancer patients were screened for carbapenemase-encoding genes that belong to Ambler classes (A), (B), and (D), followed by genotypic characterization by enterobacterial-repetitive-Intergenic-consensus–polymerase chain reaction (ERIC–PCR) and multilocus-sequence-typing (MLST). Results A total of 94.1% of CRAB isolates co-harbored more than one carbapenemase-encoding gene. The genes bla NDM , bla OXA-23 -like, and bla KPC showed the highest prevalence, with rates of 23 (67.7%) , 19 (55.9%), and 17 (50%), respectively. ERIC-PCR revealed 19 patterns (grouped into 9 clusters) . MLST analysis identified different sequence types (STs) (ST-268, ST-195, ST-1114, and ST-1632) that belong to the highly resistant easily spreadable International clone II (IC II). Genotype diversity indicated the dissemination of carbapenem-hydrolyzing, β-lactamase-encoding genes among genetically unrelated isolates. We observed a high prevalence of metallo-β-lactamase (MBL)-encoding genes (including the highly-resistant bla NDM gene that is capable of horizontal gene transfer) and of isolates harboring multiple carbapenemase-encoding genes from different classes. Conclusion The findings are alarming and call for measures to prevent and control the spread of MBL-encoding genes among bacteria causing infections in cancer patients and other immunocompromised patient populations.

Phenotypic and Genotypic Characterization of Metallo Beta Lactamases among Gram-Negative Uropathogens from a Tertiary Care Hospital in Egypt: A Cross Sectional Study

“…So, CDT represents a good screening test being simple, not time or money consuming with accepted sensitivity and specificity. Some isolates showed phenotypic MBL activity with negative PCR results that could be simply explained by presence of other MBLs genes that we did not look for in our study eg blaSPM, blaSIM, blaGIM which were reported by a recent study in Egypt [21]. On the other hand, some isolates showed no phenotypic MBL activity although PCR results were positive that could be due to the environmental factors interfering with the phenotypic expression of the MBL genes and compromising the sensitivity of the phenotypic method compared to the molecular method [22].…”

“…So, our study was focused on these three genes. However other MBL genes have been reported in Egypt less commonly [21]. It is worth mention that although reports of MBL genes (IPM, VIM and NDM) among GNB have been published worldwide yet reports from Africa and Middle East countries [25][26][27][28][29][30][31] are relatively limited.…”

“…Twelve isolates representing 54.5% showed co-expression of more than one MBL gene. Coexistence of MBL genes have been previously reported in Egypt [21,35,36] and other countries [37][38][39][40] where misuse of antimicrobials is a common malpractice. The rising prevalence of coexisting MBL genes GNB could be attributed to the association of these genes with integrons and/or transposons that facilitates the movement of resistance genes between in plasmids.…”

Prevalence of β-lactamase-encoding genes and molecular typing of Acinetobacter baumannii isolates carrying carbapenemase OXA-24 in children

“…We could not find A. baumannii isolates harboring bla VIM , bla GES , bla VEB , and bla NDM genes. In contrast, a high prevalence rate of bla NDM gene has been observed in CRAB isolates from Egyptian patients [ 22 ]. The bla OXA-23-like was more prevalent in our study, which is in agreement with previous studies [ 17 , 23 ].…”

Antibiotic resistance in the patient with cancer: Escalating challenges and paths forward

“…32,62,63 We have summarized several studies in which ESKAPE pathogens were isolated from patients with cancer since 2015 in Table 2. 31,[59][60][61][62][64][65][66][67][68][69][70][71][72][73][74] These illustrate the prevalence of MDR in different ESKAPE pathogens and highlight that prior antibiotic exposure and hospital-acquired infections are the major risk factors for developing antibiotic resistance in patients with cancer. For Figure 1, we derived data from the National Healthcare Safety Network (NHSN) 2015 to 2017 adult and pediatric antibiotic resistance reports 75,76 to illustrate differences between the percentage of central line-associated bloodstream infections by ESKAPE pathogens that tested nonsusceptible to selected antimicrobial agents.…”