Plasmid-mediated colistin resistance in a patient infected with Klebsiella pneumoniae

Genomic epidemiology and transmission characteristics of mcr1-positive colistin-resistant Escherichia coli strains circulating at natural environment

MCR-positive Escherichia coli (MCRPEC) have been reported in humans worldwide. The high prevalence of mcr-1 poses clinical and environmental risks due to its diverse genetic mechanisms. Given the vital role of animals and the environment in the spread of antibiotic resistance, a "One Health" perspective should be taken when addressing antimicrobial resistance issues. This study conducted a prospective study in six farms (located in Jiaxing City, Zhejiang province, China) in 2019. MCRPEC strains were screened from samples of different sources. The molecular epidemiological surveys and transmission potential were investigated by whole-genome sequencing and phylogenetic analysis. MCRPEC were detected in different farms with various sources. Sequence type complex 10 was dominant and distributed widely in multiple sources. Core-genome multilocus sequence type (cgMLST) analysis indicated that clonal transmission could occur within and between farms. In addition, mcr-1 genes with different locations showed different transmission tendencies. The study indicated that interspecies and cross-regional transmission of MCRPEC could occur between different sectors in farms. Further surveillance and research of non-clinical MCRPEC strains are necessary to reduce the threat of MCRPEC.

Bis(Tryptophan) Amphiphiles Form Ion Conducting Pores and Enhance Antimicrobial Activity against Resistant Bacteria

The compounds referred to as bis(tryptophan)s (BTs) have shown activity as antimicrobials. The hypothesis that the activity of these novel amphiphiles results from insertion in bilayer membranes and transport of cations is supported by planar bilayer voltage-clamp studies reported herein. In addition, fluorescence studies of propidium iodide penetration of vital bacteria confirmed enhanced permeability. It was also found that BTs having either meta-phenylene or n-dodecylene linkers function as effective adjuvants to enhance the properties of FDA-approved antimicrobials against organisms such as S. aureus. In one example, a BT-mediated synergistic effect enhanced the potency of norfloxacin against S. aureus by 128-fold. In order to determine if related compounds in which tryptophan was replaced by other common amino acids (H₂N-Aaa-linker-Aaa-NH₂) we active, a family of analogs have been prepared, characterized, and tested as controls for both antimicrobial activity and as adjuvants for other antimicrobials against both Gram-negative and Gram-positive bacteria. The most active of the compounds surveyed remain the bis(tryptophan) derivatives.

Twenty-Two years of dengue fever (1996-2017): an epidemiological study in a Brazilian city

This ecological study analyzed the temporal pattern of clinically diagnosed and laboratory confirmed dengue cases in Belo Horizonte, Minas Gerais, Brazil from 1996 to 2017. The study was divided into two analytical parts, the first of which evaluated the association between dengue incidence and host and climatic factors. The second part encompassed data from 2002 to 2017 and examined dengue incidence in relation to virus serotype and an intra-urban socioeconomic index. Over 22 years there were 469,171 cases and four epidemic peaks. There was an increase in the number, severity, and lethality of cases over the last 10 years of the study period. Biological and environmental factors appear to modulate the behavior of dengue in a large urban center.

Drug Therapy Problems and the Role of Clinical Pharmacist in Surgery Ward: Prospective Observational and Interventional Study

BACKGROUND

Drug therapy problems (DTPs) are of major concern in health care because of the associated increased cost of treatment, morbidity, and mortality. Thus, clinical practice should constitute the mainstream practice of clinical pharmacy in every ward. However, nothing is known about DTPs and the role of clinical pharmacist in the surgical ward of Ethiopia (the neglected ward).

OBJECTIVE

To assess the prevalence of DTP among patients hospitalized at the surgical ward and the role of clinical pharmacists in their identification and resolution.

METHODS

Hospital-based prospective observational and interventional study design was used with daily patients' chart review using a semi-structured questionnaire among hospitalized adult patients at the surgical ward. After identification of DTP, verbal communication was used as a means of intervention with the treating physician. Acceptance of clinical pharmacist's intervention was considered only if a change was made to the patients' medication order. To identify determinants of DTPs, multiple stepwise forward logistic regression analysis was done by SPSS version 20.0. Statistical significance was considered at p-value < 0.05. Written informed consent was sought and the data were secured.

RESULTS

The response rate was 97.1% (300) for the final analysis. The mean (±SD = standard deviation) age of the participants was 42.62 ±18.29 with male (67%) predominance. DTP was identified in 76% of study participants. A total of 449 DTPs were identified, which equates with an average of 1.97 per patient. Dose too low 124/449 (27.6%) and dose too high 81/449 (18.0%) were found to be the most common types of DTPs. The intervention rate was 86.0% (196/228 per patients) and 86.2% (387/449 DTPs), with the acceptance rate of 85.2% (167/196 per patients) and 78% (302/387 per DTP) which mean (67.3%) 302/449 of the problems were fully resolved by the clinical pharmacist. Poly-pharmacy [AOR, 7.23; 95% CI, 2.29-22.13: P-value < 0.001] and hospital stay > 20 days [AOR, 5.42; 95% CI, 2.74-10.70; p < 0.001] were the only independent predictors for DTPs.

CONCLUSION AND RECOMMENDATION

This study identified a high prevalence of DTP which was independently predicted by the presence of poly-pharmacy and >20 days of hospital stay. The rate of intervention provided and acceptance from the physician was high, which is one indicator that the role of clinical pharmacists in the identification and resolution of DTP was paramount in the surgery ward and should be implemented as a must not as optional.

Epidemiology of colistin-resistant, carbapenemase-producing Enterobacteriaceae and Acinetobacter baumannii in Croatia

Colistin is a last-resort antibiotic for the treatment of infections caused by multidrug and carbapenem-resistant Gram-negative bacteria. Colistin resistance has been emerging and multiple outbreaks have been reported in Europe and elsewhere. It has been most frequently reported in carbapenem-resistant K. pneumoniae. In this study, 24 multidrug and colistin-resistant clinical isolates (14 K. pneumoniae, one E. aerogenes, one E. cloacae, and eight A. baumannii) were collected from four hospitals in Croatia from 2013 to 2018, in order to analyse the molecular epidemiology and mechanisms of antibiotic resistance. β-lactamase and carbapenemase genes were detected by PCR. Genotyping was done on selected isolates by rep-PCR. Whole genome sequencing (WGS) was performed to discover possible molecular mechanisms for the observed colistin resistance. All isolates, except two K. pneumoniae isolates, were extensively drug resistant. Ten out of 16 (63%) K. pneumoniae isolates possessed bla_OXA-48, which is the most common carbapenem resistance gene in Croatia and in other parts of Europe. All A. baumannii isolates possessed the OXA-23-like carbapenem hydrolysing oxacillinase and five turned out to be pandrug-resistant. Colistin resistance was most likely chromosomally mediated. After sequence analysis, none of the isolates were found to possess any of the mcr gene variants. Several previously reported mutations were found in PmrB, PhoP, PhoQ, and MgrB, which are associated with colistin resistance. In the global phylogenetic analysis, DNA mutations causing mutations in the MgrB protein were present mostly in lineages comprising colistin resistant isolates, and the second most prevalent mutation (K3X) was also encountered in our isolates. In addition, based on genotyping by rep-PCR, the spread of colistin resistance is most likely to be clonal. Most importantly, the presence of colistin resistance together with carbapenemase genes in extensively drug resistant isolates poses real threats in the use of carbapenems and colistin to fight infections.

Impact of the ST101 clone on fatality among patients with colistin-resistant Klebsiella pneumoniae infection

Objectives

We describe the molecular characteristics of colistin resistance and its impact on patient mortality.

Methods

A prospective cohort study was performed in seven different Turkish hospitals. The genotype of each isolate was determined by MLST and repetitive extragenic palindromic PCR (rep-PCR). Alterations in mgrB were detected by sequencing. Upregulation of pmrCAB, phoQ and pmrK was quantified by RT-PCR. mcr-1 and the genes encoding OXA-48, NDM-1 and KPC were amplified by PCR.

Results

A total of 115 patients diagnosed with colistin-resistant K. pneumoniae (ColR-Kp) infection were included. Patients were predominantly males (55%) with a median age of 63 (IQR 46-74) and the 30 day mortality rate was 61%. ST101 was the most common ST and accounted for 68 (59%) of the ColR-Kp. The 30 day mortality rate in patients with these isolates was 72%. In ST101, 94% (64/68) of the isolates had an altered mgrB gene, whereas the alteration occurred in 40% (19/47) of non-ST101 isolates. The OXA-48 and NDM-1 carbapenemases were found in 93 (81%) and 22 (19%) of the total 115 isolates, respectively. In multivariate analysis for the prediction of 30 day mortality, ST101 (OR 3.4, CI 1.46-8.15, P = 0.005) and ICU stay (OR 7.4, CI 2.23-29.61, P = 0.002) were found to be significantly associated covariates.

Conclusions

Besides ICU stay, ST101 was found to be a significant independent predictor of patient mortality among those infected with ColR-Kp. A significant association was detected between ST101 and OXA-48. ST101 may become a global threat in the dissemination of colistin resistance and the increased morbidity and mortality of K. pneumoniae infection.

Serological evidence of Rift Valley fever virus infection in slaughtered ruminants in Nigeria

The risk of exposure of slaughterhouse workers to Rift Valley fever (RVF) virus-infected animals in Nigeria was assessed by determining the prevalence of anti-RVF IgM in cattle, goats and sheep slaughtered in a major abattoir in Ibadan, Nigeria. Blood samples were collected from 290 animals in Bodija Municipal abattoir, Ibadan, Nigeria in January and February 2017 and analyzed for the presence of RVF virus using IgM Enzyme-Linked Immunosorbent Assay (ELISA) and Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) for detection of the virus RNA. Descriptive statistics was used to analyze data. Overall, an IgM prevalence of 0.7% (2/290) was found among the blood samples of the animals, suggesting recent exposure to the virus. Antibody was detected in the sera from a cow and one goat. RVF virus RNA was not detected in the 2 IgM positive blood samples. There was no statistically significant relationship between RVF IgM infection and some variables of the animals, including age, sex and breed (p ≥ 0.05). Results of this study indicate active RVF virus transmission in domestic livestock in Nigeria. The study emphasizes the need to embark on monitoring of human and animal populations to prevent outbreak of the virus in the country.

First clinical case of KPC-3-producing Klebsiella michiganensis in Europe

Klebsiella michiganensis is a newly emerging human pathogen. We describe a case of bloodstream infection in an immunocompromised patient. The pathogen was repeatedly isolated from blood and one rectal swab, and was identified using routine standard procedures. Further investigations revealed that the K. michiganensis was multidrug resistant, carrying a plasmid harbouring a Klebsiella pneumoniae carbapenemase (KPC)-3 carbapenemase gene. This plasmid has been frequently encountered in K. pneumoniae isolates in Europe but has never been described in K. michiganensis.

Colistin resistance prevalence in Escherichia coli from domestic animals in intensive breeding farms of Jiangsu Province

The global dissemination of colistin resistance has received a great deal of attention. Recently, the plasmid-mediated colistin resistance encoded by mcr genes in Escherichia coli (E. coli) strains from animals, food, and patients in China has been reported frequently. To investigate the colistin resistance and mcr-1 and mcr-2 genes spread in domestic animals in Jiangsu Province, we collected fecael swabs from pigs, chicken and cattle at different ages distributed in intensive feeding farms. The selective chromogenic agar and mcr-PCR were used to screen the colistin resistance and mcr gene carriage. Colistin resistant E. coli colonies were identified in 54.25% (440/811), 35.96% (443/1232), and 26.92% (42/156) faecal swabs from pigs, chickens, and cattle, respectively. The prevalence of mcr-1 in colistin resistant E. coli isolates from pigs, chickens and cattle was 68.86% (303/440), 87.58% (388/443), and 71.43% (30/42), respectively, compared to mcr-2 which was present in 46.82% (206/440), 14.90% (66/443), and 19.05% (8/42) of the colistin-resistant E. coli isolated from pigs, chickens and cattle, respectively. Co-occurrence of mcr-1 and mcr-2 was identified in 20% (88/440) in pigs, 7.22% (32/443) in chickens, and 9.52% (4/42) in cattle. Interventions and alternative options are necessary to minimise further dissemination of mcr between food-producing animals and human.

Expansion of KPC-producing Klebsiella pneumoniae with various mgrB mutations giving rise to colistin resistance: the role of ISL3 on plasmids

mcr-1 has been reported as the first plasmid-encoded gene conferring colistin resistance. In KPC-producing Klebsiella pneumoniae (KPC-KP), however, colistin resistance is rapidly emerging through other mechanisms. Resistance is frequently due to disruption of the mgrB gene by insertion sequences, e.g. ISL3. The aim of this study was to investigate the expansion of mgrB-mutated KPC-KP isolates. In addition, the localisation and targets of ISL3 sequences within the core and accessory genome of common KPC-KP lineages were identified. A total of 29 clinical K. pneumoniae isolates collected from Italian patients were randomly selected. Whole genome sequences were analysed for resistance genes, plasmids and insertion sequences. In addition, 27 colistin-resistant KPC-KP isolates from a previous study from Crete (Greece) were assessed. Clonal expansion of KPC-KP isolates with various mutations in mgrB among all lineages was observed. In two Italian MLST ST512 isolates and eight Greek ST258 isolates, an identical copy of ISL3 was inserted in mgrB nucleotide position 133. ISL3, a transposable restriction-modification system of 8154 nucleotides, was located on pKpQIL-like plasmids and may transpose into the chromosome. In four isolates, chromosomal integration of ISL3 in diverse inner membrane proteins other than mgrB was identified. Colistin resistance is most often explained by clonal expansion of isolates with mutated mgrB. pKpQIL-like plasmids, which are omnipresent in KPC-KP, carry insertion sequences such as ISL3 that have mgrB as a target hotspot for transposition. Transposition of insertion sequences from plasmids and subsequent clonal expansion may contribute to the emerging colistin resistance in KPC-KP.