Comparison of Molecular and Phenotypic Methods for the Detection and Characterization of Carbapenem Resistant Enterobacteriaceae

In recent years, there has been a rapid dissemination of carbapenem resistant Enterobacteriaceae (CRE). This study aimed to compare phenotypic and molecular methods for detection and characterization of CRE isolates at a large tertiary care hospital in Saudi Arabia. This study was carried out between January 2011 and November 2013 at the King Khalid University Hospital (KKUH) in Saudi Arabia. Determination of presence of extended-spectrum beta-lactamases (ESBL) and carbapenem resistance was in accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines. Phenotypic classification was done by the MASTDISCSTM ID inhibitor combination disk method. Genotypic characterization of ESBL and carbapenemase genes was performed by the Check-MDR CT102. Diversilab rep-PCR was used for the determination of clonal relationship. Of the 883 ESBL-positive Enterobacteriaceae detected during the study period, 14 (1.6%) isolates were carbapenem resistant. Both the molecular genotypic characterization and phenotypic testing were in agreement in the detection of all 8 metalo-beta-lactamases (MBL) producing isolates. Of these 8 MBL-producers, 5 were positive for blaNDM gene and 3 were positive for blaVIM gene. Molecular method identified additional blaOXA gene isolates while MASTDISCSTM ID detected one AmpC producer isolate. Both methods agreed in identifying 2 carbapenem resistant isolates which were negative for carbapenemase genes. Diversilab rep-PCR analysis of the 9 Klebsiella pneumoniae isolates revealed polyclonal distribution into eight clusters. MASTDISCSTM ID is a reliable simple cheap phenotypic method for detection of majority of carbapenemase genes with the exception of the blaOXA gene. We recommend to use such method in the clinical laboratory

SARS-CoV-2 B.1.1.7 UK Variant of Concern Lineage-Related Perceptions, COVID-19 Vaccine Acceptance and Travel Worry Among Healthcare Workers

Background: Healthcare workers' (HCWs') travel-related anxiety needs to be assessed in light of the emergence of SARS-CoV-2 mutations. Methods: An online, cross-sectional questionnaire among HCWs between December 21, 2020 to January 7, 2021. The outcome variables were HCWs' knowledge and awareness of the SARS-CoV-2 B.1.1.7 lineage that was recently reported as the UK variant of concern, and its associated travel worry and Generalized Anxiety Disorder (GAD-7) score. Results: A total of 1,058 HCWs completed the survey; 66.5% were female, 59.0% were nurses. 9.0% indicated they had been previously diagnosed with COVID-19. Regarding the B.1.1.7 lineage, almost all (97.3%) were aware of its emergence, 73.8% were aware that it is more infectious, 78.0% thought it causes more severe disease, and only 50.0% knew that current COVID-19 vaccines are effective in preventing it. Despite this, 66.7% of HCWs were not registered to receive the vaccine. HCWs' most common source of information about the new variant was social media platforms (67.0%), and this subgroup was significantly more worried about traveling. Nurses were more worried than physicians (P = 0.001). Conclusions: Most HCWs were aware of the emergence of the SARS-CoV-2 B.1.1.7 variant and expressed substantial travel worries. Increased worry levels were found among HCWs who used social media as their main source of information, those with lower levels of COVID-19 vaccine uptake, and those with higher GAD-7 scores. The utilization of official social media platforms could improve accurate information dissemination among HCWs regarding the Pandemic's evolving mutations. Targeted vaccine campaigns are warranted to assure HCWs about the efficacy of COVID-19 vaccines toward SARS-CoV-2 variants

Molecular typing of ST239-MRSA-III from diverse geographic locations and the evolution of the SCCmec III element during its intercontinental spread

ST239-MRSA-III is probably the oldest truly pandemic MRSA strain, circulating in many countries since the 1970s. It is still frequently isolated in some parts of the world although it has been replaced by other MRSA strains in, e.g., most of Europe. Previous genotyping work (Harris et al., 2010; Castillo-Ramírez et al., 2012) suggested a split in geographically defined clades. In the present study, a collection of 184 ST239-MRSA-III isolates, mainly from countries not covered by the previous studies were characterized using two DNA microarrays (i) targeting an extensive range of typing markers, virulence and resistance genes and (ii) a SCCmec subtyping array. Thirty additional isolates underwent whole-genome sequencing (WGS) and, together with published WGS data for 215 ST239-MRSA-III isolates, were analyzed using in-silico analysis for comparison with the microarray data and with special regard to variation within SCCmec elements. This permitted the assignment of isolates and sequences to 39 different SCCmec III subtypes, and to three major and several minor clades. One clade, characterized by the integration of a transposon into nsaB and by the loss of fnbB and splE was detected among isolates from Turkey, Romania and other Eastern European countries, Russia, Pakistan, and (mainly Northern) China. Another clade, harboring sasX/sesI is widespread in South-East Asia including China/Hong Kong, and surprisingly also in Trinidad & Tobago. A third, related, but sasX/sesI-negative clade occurs not only in Latin America but also in Russia and in the Middle East from where it apparently originated and from where it also was transferred to Ireland. Minor clades exist or existed in Western Europe and Greece, in Portugal, in Australia and New Zealand as well as in the Middle East. Isolates from countries where this strain is not epidemic (such as Germany) frequently are associated with foreign travel and/or hospitalization abroad. The wide dissemination of this strain and the fact that it was able to cause a hospital-borne pandemic that lasted nearly 50 years emphasizes the need for stringent infection prevention and control and admission screening

Characterisation of S. aureus/MRSA CC1153 and review of mobile genetic elements carrying the fusidic acid resistance gene fusC

While many data on molecular epidemiology of MRSA are available for North America, Western Europe and Australia, much less is known on the distribution of MRSA clones elsewhere. Here, we describe a poorly known lineage from the Middle East, CC1153, to which several strains from humans and livestock belong. Isolates were characterised using DNA microarrays and one isolate from the United Arab Emirates was sequenced using Nanopore technology. CC1153 carries agr II and capsule type 5 genes. Enterotoxin genes are rarely present, but PVL is common. Associated spa types include t504, t903 and t13507. PVL-positive CC1153-MSSA were found in Egyptian cattle suffering from mastitis. It was also identified among humans with skin and soft tissue infections in Saudi Arabia, France and Germany. CC1153-MRSA were mainly observed in Arabian Gulf countries. Some isolates presented with a previously unknown SCCmec/SCCfus chimeric element in which a mec B complex was found together with the fusidic acid resistance gene fusC and accompanying genes including ccrA/B-1 recombinase genes. Other isolates carried SCCmec V elements that usually also included fusC. Distribution and emergence of CC1153-MRSA show the necessity of molecular characterization of MRSA that are resistant to fusidic acid. These strains pose a public health threat as they combine resistance to beta-lactams used in hospitals as well as to fusidic acid used in the community. Because of the high prevalence of fusC-positive MRSA in the Middle East, sequences and descriptions of SCC elements harbouring fusC and/or mecA are reviewed. When comparing fusC and its surrounding regions from the CC1153 strain to available published sequences, it became obvious that there are four fusC alleles and five distinct types of fusC gene complexes reminiscent to the mec complexes in SCCmec elements. Likewise, they are associated with different sets of ccrA/B recombinase genes and additional payload that might include entire mec complexes or SCCmec elements

Susceptibility pattern of multi-drug resistance Pseudomonas aeruginosa isolates from tertiary care hospital in Riyadh, KSA

Objectives: Pseudomonas aeruginosa is important pathogens commonly cause nosocomial infections. The occurrence of multi-resistant organisms (MROs) of Pseudomonas aeruginosa strains have been increased worldwide and limiting the therapeutic options. The MRO of Pseudomonas aeruginosa phenotype can be mediated by a variety of resistance mechanisms and highly versatile property to mutate. Therefore the our study aimed to evaluate the resistance pattern of Pseudomonas aeruginosa collected from Riyadh tertiary care hospital, Kingdom of Saudi Arabia. Methods: During the period from 2019 to 2021 clinical samples were collected from microbiology lab at King Khalid University Hospital and analysed for the antibiotic susceptibility pattern. Results: Suggested that the rates of resistance for the three years were higher for isolates collected from patients older than 50 years if its compared with the strains collected from young age. A total of 1024 Pseudomonas aeruginosa isolates were collected during the last three years, the prevalence rate were 44.6%, 32.6% and 22.7% during the period of 2019, 2020, and 2021 respectively. Meanwhile, the highest percentages of multi drug resistance Pseudomonas aeruginosa strains were recovered from body fluids; about 38 (47.5%) out of 80 Pseudomonas aeruginosa isolates were MRO Pseudomonas aeruginosa. The rate of resistances showed that Imipenem was significantly higher in resistant among the clinical isolates (77.8%), then Meropenem (61%), Aztreonam (42%) and Ceftazidime (36%) than other antibiotics. Most of isolates were sensitive to colistin except (2.7%) were resistance. Moreover, antibiotic resistant bacteria have been observed with increasing frequency over the past three years. Conclusions: The current study reports that the susceptibility among P. aeruginosa isolates have been decreased in KSA, perhaps due to the massive use of antibiotics, the lack of adherence to approved infection control practices by hospitals, or due to the changes to the public health infrastructure

Antimicrobial resistance: A round table discussion on the "One Health" concept from the Gulf Cooperation Council Countries. Part Two: A focus on Human Health

The Gulf Cooperation Council Center for Infection Control (GCC-IC) has moved forward over the past several years on the antimicrobial resistance (AMR) agenda. Many of the GCC countries have now developed a national plan to combat AMR and have engaged the leadership of the involved sectors in the discussion on how to mitigate this threat. During the first meeting for the GCC-IC center on AMR, which took place early 2015, the roadmap for combating AMR was developed [1] and since then much more has been done. We present here the discussion that took place during the second GCC-IC center meeting on AMR where not only have the countries presented their progress, but we conducted 2 round table discussions inviting international and regional experts in the field to share their thoughts, progress and knowledge on this topic [2]. Within is the 2nd round table discussion at the 2017 GCC AMR meeting which took place in Riyadh, Saudi Arabia, April 2017. Where the 1st round table discussion during this meeting addressed the role of leadership in managing AMR [2]

Detection of clostridium difficile antigen and toxin in stool specimens: Comparison of the C. difficile quik chek complete enzyme immunoassay and GeneXpert C. difficile polymerase chain reaction assay

Background/Aims: Accurate and rapid laboratory diagnosis of Clostridium difficile infections (CDI) remains a significant challenge. A two-step algorithm for detection of toxigenic C. difficile in stool based on initial screening for glutamate dehydrogenase assay followed by confirmation by toxin A+B detection using an enzyme immunoassay (EIA) or molecular assay has been proposed. We aimed to evaluate the C. difficile Quik Chek Complete® (QCC-EIA) versus the GeneXpert® C. difficile polymerase chain reaction (PCR) assay in this two-step algorithm. Materials and Methods: Two hundred and ten liquid stool samples obtained between June 2014 and June 2015 from patients suspected of CDI were tested by the QCC-EIA and GeneXpert PCR assay. The GeneXpert assay was used as the reference standard to calculate the QCC-EIA sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results: Of the 210 stool samples tested, 43 (20.5%) were positive by QCC-EIA, while 31 (14.8%) were positive by GeneXpert assay. The sensitivity and specificity of the QCC-EIA were found to be 100 and 93%, respectively; the PPV and NPV were 72 and 100%, respectively. The binary toxin was detected in 12 (38.7%) and tcdC gene deletion in 3 (9.6%). Conclusions: The low specificity of QCC-EIA makes it less reliable as a confirmatory test for CDI diagnosis. This test may be used as a screening test in a two-step algorithm when combined with a molecular assay or another confirmatory test

Screening for the antimicrobial activity of Salvadora persica extracts against Enterococcus faecalis and Candida albicans

Antimicrobial resistance of Enterococcus faecalis (E. faecalis) and Candida albicans (C.albicans), frequently implicated in dental infections, remains a challenge. Using a variety of solvents this study was performed to screen the antimicrobial activity of Salvadora persica (S. persica) extracts against these two organisms. Seven extracts of S. Persica were prepared using hexane, chloroform, ethyl acetate, methanol-soluble, methanol-insoluble, ethanol, and water. Antimicrobial activities against E. faecalis and C.albicans were assessed by colony forming unit (CFU) counts after 1, 3, 6 and 24 hours of exposure using doubling dilutions of the extracts ranging between 125 µg to 1mg/ml. Among the extracts of S. persica tested, hexane extract induced a steady and progressive reduction in CFUs of both the E. faecalis (p<0.001) and C. albicans (p<0.01) at all concentrations beginning after 3 hours until 24 hours. Progressive inhibition of E. faecalis CFUs was also observed for ethanol beginning at 3 hours until 24 hours  (p <0.001) and chloroform only at 24 hours (p<0.001) at all concentrations. Ethyl acetate extract of S. persica was effective against C. albicans at 250µg/mg after 6 hours (p<0.02) and 24 hours (p <0.002). No significant changes were observed in any of the other tested extracts of S. persica. Hexane extract of S. persica was found to exhibit maximum antimicrobial activity against E. faecalis and C.albicans. Further studies are recommended for evaluation of this extract as an effective anti-microbial agent