Cooccurrence of NDM-1, ESBL, RmtC, AAC(6′)-Ib, and QnrB in Clonally Related Klebsiella pneumoniae Isolates Together with Coexistence of CMY-4 and AAC(6′)-Ib in Enterobacter cloacae Isolates from Saudi Arabia

The aim of this study was to investigate the mechanisms responsible for resistance to antimicrobials in a collection of enterobacterial isolates recovered from two hospitals in Saudi Arabia. A total of six strains isolated from different patients showing high resistance to carbapenems was recovered in 2015 from two different hospitals, with four being Klebsiella pneumoniae and two Enterobacter cloacae. All isolates except one K. pneumoniae were resistant to tigecycline, but only one K. pneumoniae was resistant to colistin. All produced a carbapenemase according to the Carba NP test, and all were positive for the EDTA-disk synergy test for detection of MBL. Using PCR followed by sequencing, the four K. pneumoniae isolates produced the carbapenemase NDM-1, while the two E. cloacae isolates produced the carbapenemase VIM-1. Genotyping analysis by Multilocus Sequence Typing (MLST) showed that three out of the four K. pneumoniae isolates were clonally related. They had been recovered from the same hospital and belonged to Sequence Type (ST) ST152. In contrast, the fourth K. pneumoniae isolate belonged to ST572. Noticeably, the NDM-1-producing K. pneumoniae additionally produced an extended-spectrum ß- lactamase (ESBL) of the CTX-M type, together with OXA-1 and TEM-1. Surprisingly, the three clonally related isolates produced different CTX-M variants, namely, CTX-M- 3, CTX-M-57, and CTX-M-82, and coproduced QnrB, which confers quinolone resistance, and the 16S rRNA methylase RmtC, which confers high resistance to all aminoglycosides. The AAC(6′)-Ib acetyltransferase was detected in both K. pneumoniae and E. cloacae. Mating-out assays using Escherichia coli as recipient were successful for all isolates. The Bla NDM-1 gene was always identified on a 70- kb plasmid, whereas the Bla VIM-1 gene was located on either a 60-kb or a 150-kb plasmid the two E. cloacae isolates, respectively. To the best of our knowledge, this is the first report of the coexistence of an MBL (NDM-1), an ESBL (CTX-M), a 16S rRNA methylase (RmtC), an acetyltransferase (AAC[6′]-Ib), and a quinolone resistance enzyme (QnrB) in K. pneumoniae isolates recovered from different patients during an outbreak in a Saudi Arabian hospital

Characterization of carbapenemases, ESBLs, and plasmid-mediated quinolone determinants in carbapenem-insensitive Escherichia coli and Klebsiella pneumoniae in Riyadh hospitals

The main objective of this work was to characterize carbapenemases, extended-spectrum β-lactamases (ESBLs), and plasmid-mediated quinolone resistance (PMQR) among carbapenem-insensitive Klebsiella pneumoniae and Escherichia coli clinical isolates which were isolated from three hospitals in Riyadh. Thirty-one carbapenem-insensitive isolates (21 K. pneumoniae and 10 E. coli) were recovered from March 2014 to May 2014. Susceptibility testing and phenotypic detection tests were used to characterize the classes of β-lactamases. PCR assays were performed for the detection of the genes encoding ESBL (blaCTX-M, blaTEM, blaSHV, and blaOXA-1), carbapenemase (blaKPC, blaGES, blaVIM, blaIMP, blaNDM, and blaOXA-48), and PMQR (qnrA, qnrB, qnrS, aac(6)-Ib-cr, qepA, oqxA, and oqxB) genes. All carbapenem-insensitive isolates were carbapenemase producers, with 41.9% and 58.1% being class B carbapenemases class D OXA-48, respectively. While the prevalence of ESBL producers was 80.6%. The following resistance genes were detected; OXA-48-like (58.1%), NDM-type (41.9%), CTX-M-1-like (77.4%), CTX-M-9-like (9.6%), TEM-1 (74.2%), OXA-1 (54.8%), SHV-1 (4.4%), qnrS (58.1%), qnrB (3.2%), and aac(6)-Ib-cr (51.6%). The predominant carbapenemases in the isolates that had carbapenem MIC ≤ 4 μg/ml and MIC ≥ 12 μg/ml were blaOXA-48-type and blaNDM-type respectively. CTX-M-1-like and qnrS were the dominant ESBL and PMQR genes, respectively. This is the first report in which qnrS was described in the isolates from Saudi Arabia. Keywords: OXA-48, NDM, Carbapenem resistance, Saudi Arabi

Fecal Colonization with Extended-Spectrum Beta-Lactamase and AmpC-Producing Escherichia coli

Background. Extended-spectrum β-lactamases (ESβLs) and AmpC β-lactamases cause β-lactam resistance in Escherichia coli. Fecal colonization by ESβL- and/or AmpC-positive E. coli is a source of nosocomial infections. Methods. In order to investigate inpatient fecal colonization by ESβLs and AmpC, antibiotic sensitivity tests were conducted and minimum inhibitory concentrations (MICs) were determined using the disk diffusion method and E-test, respectively. Characterization of ESβL and AmpC was performed using E-test strips, and a set of PCRs and DNA sequence analyses were used to characterize the ESβL and AmpC genes. Results. The whole collection of E. coli isolates (n=50) was sensitive to imipenem, tigecycline, colistin, and fosfomycin, while 26% of the isolates showed reduced susceptibility to ceftazidime (MIC ≥ 4 μg/mL). ESβL was phenotypically identified in 26% (13/50) of cases, while AmpC activity was detected in two ESβL-producing E. coli isolates. All ESβL-producing E. coli were positive for the CTX-M gene, eleven isolates carried blaCTX-M-15, and two isolates carried blaCTX-M-14 gene. Two CTX-M-positive E. coli isolates carried blaCMY-2. Conclusions. The alimentary tract is a significant reservoir for ESβL- and/or AmpC-producing E. coli, which may lead to nosocomial infection

Synthesis, Single Crystal X-ray Analysis, and Antifungal Profiling of Certain New Oximino Ethers Bearing Imidazole Nuclei

Fungal infections threaten human health, particularly in immune-compromised patients worldwide. Although there are a large number of antifungal agents available, the desired clinical attributes for the treatment of fungal infections have not yet been achieved. Azoles are the mainstay class of the clinically used antifungal agents. In the current study, the synthesis, spectroscopic characterization, and antifungal activity of certain new oximino ethers Va–n bearing imidazole nuclei are reported. The (E)-configuration of the imine double bond of the synthesized compounds Va–n has been confirmed via single crystal X-ray analysis of compound Vi as a representative example of this class of compounds. The molecular structure of compound Vi was crystallized in the monoclinic, P21/c, a = 18.7879(14) Å, b = 5.8944(4) Å, c = 16.7621(12) Å, β = 93.063(3)°, V = 1855.5(2) Å3, Z = 4. The in vitro antifungal activity of the synthesized compounds Va–n were evaluated using diameter of the inhibition zone (DIZ) and minimum inhibitory concentration (MIC) assays against different fungal strains. Compound Ve manifested anti-Candida albicans activity with an MIC value of 0.050 µmol/mL, being almost equipotent with the reference antifungal drug fluconazole (FLC),while compounds Vi and Vn are the most active congeners against Candida parapsilosis, being equipotent and about twenty-three times more potent than FLC with an MIC value of 0.002 µmol/mL. The results of the current report might support the development of new potent and safer antifungal azoles

Synthesis and Spectroscopic Identification of Certain Imidazole-Semicarbazone Conjugates Bearing Benzodioxole Moieties: New Antifungal Agents

During the last three decades the extent of life-threatening fungal infections has increased remarkably worldwide. Synthesis and structure elucidation of certain imidazole-semicarbazone conjugates 5a–o are reported. Single crystal X-ray analysis of compound 5e unequivocally confirmed its assigned chemical structure and the (E)-configuration of its imine double bond. Compound 5e crystallized in the triclinic system, P-1, a = 6.3561 (3) Å, b = 12.5095 (8) Å, c = 14.5411 (9) Å, α = 67.073 (4)°, β = 79.989 (4)°, γ =84.370 (4)°, V = 1048.05 (11) Å3, Z = 2. In addition, DIZ and MIC assays were used to examine the in vitro antifungal activity of the title conjugates 5a–o against four fungal strains. Compound 5e, bearing a 4-ethoxyphenyl fragment, showed the best MIC value (0.304 µmol/mL) against both C. tropicalis and C. parapsilosis species, while compounds 5c (MIC = 0.311 µmol/mL), 5k, and 5l (MIC = 0.287 µmol/mL) exhibited the best anti-C. albicans activity

Fecal Colonization with Extended-Spectrum Beta-Lactamase and AmpC-Producing Escherichia coli

Background. Extended-spectrum -lactamases (ES Ls) and AmpC -lactamases cause -lactam resistance in Escherichia coli. Fecal colonization by ES L-and/or AmpC-positive E. coli is a source of nosocomial infections. Methods. In order to investigate inpatient fecal colonization by ES Ls and AmpC, antibiotic sensitivity tests were conducted and minimum inhibitory concentrations (MICs) were determined using the disk diffusion method and E-test, respectively. Characterization of ES L and AmpC was performed using E-test strips, and a set of PCRs and DNA sequence analyses were used to characterize the ES L and AmpC genes. Results. The whole collection of E. coli isolates ( = 50) was sensitive to imipenem, tigecycline, colistin, and fosfomycin, while 26% of the isolates showed reduced susceptibility to ceftazidime (MIC ≥ 4 g/mL). ES L was phenotypically identified in 26% (13/50) of cases, while AmpC activity was detected in two ES L-producing E. coli isolates. All ES L-producing E. coli were positive for the CTX-M gene, eleven isolates carried , and two isolates carried CTX-M-14 gene. Two CTX-M-positive E. coli isolates carried CMY-2 . Conclusions. The alimentary tract is a significant reservoir for ES L-and/or AmpC-producing E. coli, which may lead to nosocomial infection

Evaluation of wound healing activity of henna, pomegranate and myrrh herbal ointment blend

This study assessed the wound healing potential and antimicrobial activity of henna, pomegranate and myrrh extract formulations and their blend in excision, and dead space wound models in rats in comparison to a marketed ointment (gentamycin). The natural extracts were used in ointment formulations alone or in a combination of three extracts at a total concentration of 15% w/w in medications. The percent of wound contraction in case of henna, myrrh, pomegranate, the blend and gentamycin (10 mg/kg) were 85.90–98.5%, 88.35–99.52%, 93.55–100%, 97.30–100%, and 90.25–100% from days 16 to 20, respectively. The blended formulation showed the highest increase in the percent of wound contraction and decrease in the epithelisation period compared to other formulations and showed comparable results to the standard ointment. The histological studies of excision biopsy at day 24 showed healed skin structures with normal epithelisation, the restoration of adnexa and fibrosis within the dermis in all of the formulation- and gentamycin-treated groups while the control group lagged behind in the formation of the amount of ground substance in the granulation tissue. The formulations showed antimicrobial activity against Candida, Staphylococcus aureus, mucous membrane infections and E. coli topical infections. The study proved the wound healing potential and antimicrobial activity of the herbal extract. Keywords: Wound healing, Henna, Pomegranate, Myrrh, Hydrophilic ointment, Herbal extrac

Complex Clonal Diversity of Staphylococcus aureus Nasal Colonization among Community Personnel, Healthcare Workers, and Clinical Students in the Eastern Province, Saudi Arabia

Here, 210 healthy participants including community personnel (70), clinical students (68), and healthcare workers (HCWs) (72) from the eastern region of Saudi Arabia were studied. Sixty-three Staphylococcus aureus isolates were obtained from the nares of 37% of the community personnel and 26% of the clinical students and HCWs. Methicillin-resistant S. aureus (MRSA) was found in 16% (10 isolates) of the 63 isolates; six were from HCWs. Molecular characterization revealed high clonal diversity among the isolates, with 19 different spa types, 12 clonal complexes (CCs), and seven sequence types (STs) detected. The most common strain type was USA900, CC15, and t084, seen in 11 methicillin-susceptible S. aureus (MSSA) isolates. Moreover, three novel spa types in six isolates and one novel ST in two isolates were identified, most from HCWs. Interestingly, 29 isolates were mecA positive by PCR, whereas only 10 isolates were MRSA by disk diffusion (cefoxitin resistant). Of the 19 MSSA mecA-positive isolates, 16 were PBP2a negative, leaving three unique isolates from HCWs that were mecA and PBP2a positive yet cefoxitin susceptible. Our findings highlight the importance of phenotypically and genotypically characterizing S. aureus strains isolated from healthy communities to monitor the risk of possible cross-transmission to hospitalized patients. The identified strains showed a clonal lineage relationship with previously reported S. aureus and MRSA strains acquired from hospital settings

Benzo[g]quinazolines as antifungal against candidiasis: Screening, molecular docking, and QSAR investigations

Candida albicans, an opportunistic pathogen, is the most common type of fungus and represents a substantial source of human invasive disease (nosocomial infection). This category of fungi are part of our microbiota, and given the appropriate environmental conditions, it has the potential to cause both superficial and systemic infections. There is a soaring resistance against the available anticandidal agents. The purpose of this research is to investigate the activity of certain previously synthesized benzo[g]quinazolines against C. albicans in vitro by using the cup-plate diffusion method. There was a marked difference in the effectiveness of the target compounds 1–6 against the sample of C. albicans that was tested. Benzo[g]quinazolines 1 (inhibition zone = 20 mm) and 2 (inhibition zone = 22 mm) had good effects in comparison to fluconazole (inhibition zone = 26 mm). A docking study was conducted between benzo[g]quinazolines 1–6 and Candida spp. CYP51 to establish the binding mode compared with fluconazole and VT-1161 (oteseconazole) as reference medicines, and it was determined that binding at the active site of Candida spp. CYP51 occurred in the same manner. Quantitative structure–activity relationship (QSAR) investigation was performed to further characterize the identified anticandidal agents and recognize the major regulatory components governing such activity. In future studies, the benzo[g]quinazoline scaffold could serve as a model for the design and development of novel derivatives with antifungal potential