Carbapenemase-Producing Non-Glucose-Fermenting Gram-Negative Bacilli in Africa, Pseudomonas aeruginosa and Acinetobacter baumannii: A Systematic Review and Meta-Analysis

Genomic epidemiology and molecular characteristics of blaNDM-1-positive carbapenem-resistant Pseudomonas aeruginosa belonging to international high-risk clone ST773 in the Gauteng region, South Africa

PURPOSE

The emergence of carbapenem-resistant P. aeruginosa (CRPA) harbouring acquired carbapenemase genes (blaVIM, blaIMP and blaNDM) has become a global public health threat. Three CRPA isolates included in the study had an extensively drug-resistant phenotype with susceptibility to colistin only and were positive for the blaNDM-1 gene. The current study aimed to investigate the genomic epidemiology and molecular characteristics of the blaNDM-1-positive CRPA isolates collected from the Gauteng region, South Africa.

METHODS

Short read whole genome sequencing (WGS) was performed to determine sequence types (STs), genetic relatedness, resistome, virulome and the genetic environment of the blaNDM-1 gene.

RESULTS

The WGS and phylogenetic analyses revealed that the study isolates belonged to an international high-risk clone ST773 and belonged to the same clade with eight blaNDM-1-positive ST773 isolates from Hungary, India, Nigeria, South Korea and USA. The study isolates harboured a wide repertoire of intrinsic and acquired antibiotic resistance genes (ARGs) related with mobile genetic elements, porins and efflux pumps, as well as virulence factor genes. The clade-specific ARGs (blaNDM-1, floR2/cmlA9, rmtB4, tetG) were found in a putative integrative and conjugative element (ICE) region similar to ICE6660-like.

CONCLUSION

As ICE carrying the blaNDM-1 gene can easily spread to other P. aeruginosa isolates and other Gram-negative bacteria, the findings in this study highlight the need for appropriate management strategies and active surveillance of CRPA isolates in the Gauteng region, South Africa.

Potential of Selected African Medicinal Plants as Alternative Therapeutics against Multi-Drug-Resistant Bacteria

Antimicrobial resistance is considered a "One-Health" problem, impacting humans, animals, and the environment. The problem of the rapid development and spread of bacteria resistant to multiple antibiotics is a rising global health threat affecting both rich and poor nations. Low- and middle-income countries are at highest risk, in part due to the lack of innovative research on the surveillance and discovery of novel therapeutic options. Fast and effective drug discovery is crucial towards combatting antimicrobial resistance and reducing the burden of infectious diseases. African medicinal plants have been used for millennia in folk medicine to cure many diseases and ailments. Over 10% of the Southern African vegetation is applied in traditional medicine, with over 15 species being partially or fully commercialized. These include the genera Euclea, Ficus, Aloe, Lippia. And Artemisia, amongst many others. Bioactive compounds from indigenous medicinal plants, alone or in combination with existing antimicrobials, offer promising solutions towards overcoming multi-drug resistance. Secondary metabolites have different mechanisms and modes of action against bacteria, such as the inhibition and disruption of cell wall synthesis; inhibition of DNA replication and ATP synthesis; inhibition of quorum sensing; inhibition of AHL or oligopeptide signal generation, broadcasting, and reception; inhibition of the formation of biofilm; disruption of pathogenicity activities; and generation of reactive oxygen species. The aim of this review is to highlight some promising traditional medicinal plants found in Africa and provide insights into their secondary metabolites as alternative options in antibiotic therapy against multi-drug-resistant bacteria. Additionally, synergism between plant secondary metabolites and antibiotics has been discussed.

Genomic characterization of an NDM-9-producing Acinetobacter baumannii clinical isolate and role of Glu152Lys substitution in the enhanced cefiderocol hydrolysis of NDM-9

Here, we characterized the first French NDM-9-producing Acinetobacter baumannii isolate. A. baumannii 13A297, which belonged to the STPas25 (international clone IC7), was highly resistant to β-lactams including cefiderocol (MIC >32 mg/L). Whole genome sequencing (WGS) using both Illumina and Oxford Nanopore technologies revealed a 166-kb non-conjugative plasmid harboring a blaNDM-9 gene embedded in a Tn125 composite transposon. Complementation of E. coli DH5α and A. baumannii CIP70.10 strains with the pABEC plasmid carrying the blaNDM-1 or blaNDM-9 gene, respectively, resulted in a significant increase in cefiderocol MIC values (16 to >256-fold), particularly in the NDM-9 transformants. Interestingly, steady-state kinetic parameters, measured using purified NDM-1 and NDM-9 (Glu152Lys) enzymes, revealed that the affinity for cefiderocol was 3-fold higher for NDM-9 (Km = 53 μM) than for NDM-1 (Km = 161 μM), leading to a 2-fold increase in catalytic efficiency for NDM-9 (0.13 and 0.069 μM-1.s-1, for NDM-9 and NDM-1, respectively). Finally, we showed by molecular docking experiments that the residue 152 of NDM-like enzymes plays a key role in cefiderocol binding and resistance, by allowing a strong ionic interaction between the Lys152 residue of NDM-9 with both the Asp223 residue of NDM-9 and the carboxylate group of the R1 substituent of cefiderocol.

Emergence of Extended-Spectrum Beta-Lactamase and Carbapenemase Producing Gram Negative Non-Fermenters at Selected Hospitals of Northeast Ethiopia: A Prospective Cross-Sectional Study

Background

The emergence and spread of extended-spectrum β-lactamases (ESβLs) and carbapenemase (CP) producing gram negative non-fermenters are becoming a serious public health threat globally. Infections caused by these pathogens limit treatment options and contribute to the significant morbidity and mortality. Thus, to reduce their spread, early detection of these superbugs is very crucial. This study therefore aimed to assess the prevalence of ESβLs and CP producing gram negative non-fermenters at selected hospitals of North East Ethiopia.

Methods

A cross-sectional study was conducted from January to June 2021. Acinetobacter baumannii (A. baumannii) and Pseudomonas aeruginosa (P. aeruginosa) were identified using standard bacteriological techniques. ESβL and CP production were detected by combined disk diffusion and modified carbapenem inhibitory methods, respectively. Data were collected via face-to-face interview and patient card review. Chi-squared and Fisher's exact tests were calculated and p-value < 0.05 was considered statistically significant.

Results

A total of 384 patients participated in this study. Overall, 30 (7.8%) patients had positive culture for A. baumannii and P. aeruginosa. The prevalence of A. baumannii was 20 (5.2%) and that of P. aeruginosa was 10 (2.6%). From the overall isolates, 16 (53.3%) were ESβL and the proportion of carbapenemase production was 4 (13.3%). ESβL production was 8 (40%) in A. baumannii and 8 (80%) in P. aeruginosa isolates. ESβL production infections were significantly associated with hospitalization (p=0.004). Intravenous catheterization, hospitalization, and surgery had significant association with ESβL production (p<0.005). All isolates of A. baumannii and P. aeruginosa were MDR.

Conclusion

ESβL and carbapenemase production among A. baumannii and P. aeruginosa were high in the selected hospitals. The treatment of such resistant infectious agents should be guided by antimicrobial susceptibility test in a study setting. Thus, restricted and wise use of antibiotics is highly recommended to contain the spread of these superbugs. Hospitals should develop infection prevention guidelines to prevent the spread of resistant pathogens in hospitalized patients.

Prevalence of multidrug-resistant and extensively drug-resistant phenotypes of Gram-negative bacilli isolated in clinical specimens at Centre Hospitalo-Universitaire Ibn Rochd, Morocco

Introduction

antimicrobial resistance in gram-negative bacilli is one of the major concerns in public health. We aimed to evaluate gram-negative bacilli epidemiology, antimicrobial profiles, and the resistance´s mechanism for Enterobacteriaceae isolated from specimens of hospitalized patients in wards of University Hospital Center Ibn Rochd of Casablanca, Morocco.

Methods

a prospective study of the patient's specimens, collected from December 2016 to 31st March 2017. Isolation and identification were performed using conventional biochemical tests. According to the European Committee on Antimicrobial Susceptibility Testing guidelines, antibiotic susceptibility was determined. Polymerase Chain Reaction (PCR) was used to detect β-lactamase and carabapenemase genes: CTX-M, SHV, TEM, OXA-48, NDM, and VIM among the Enterobacteriaceae.

Results

according to inclusion criteria, 38 Enterobacteriaceae, 25 Acinetobacter baumannii (A. baumannii), and 10 Pseudomonas aeruginosa (P. aeruginosa) were included during the study period; these bacteria were mainly responsible for bacteremia. Fifty-five percent of enterobacteria were extended-spectrum β-lactamase (ESBL), 42% EBSL and carbapenemase, and 3% carbapenemase, with high coresistances. Eighty-four percent of A. baumannii were XDR. All P. aeruginosa were MDR; amikacin showed the best activity (70% susceptibility). The genotypic approach revealed the presence of blaCTX-M, blaSHV, blaTEM in 68%, 22%, and 11% respectively. Of the 22 carbapenemase-producers, 41% were blaOXA-48 and 18% blaNDM; none had blaVIM. Furthermore, various genes coexistence were detected: blaCTX-M+blaOXA-48; blaCTX-M+blaNDM; blaCTX-M+blaSHV+blaOXA-48; and blaSHV+blaOXA-48.

Conclusion

findings revealed highly resistance rate among isolates. This raises the need to control antibiotics and regular screening to identify dynamics promoting resistance. Thus, we recommend developing antimicrobial stewardship programs and improving hygiene systems to prevent the nosocomial spreading of these phenotypes in our center.

Antimicrobial Resistance Profile of Pseudomonas aeruginosa from Different Clinical Samples in Debre Tabor Comprehensive Specialized Hospital, Northwest Ethiopia

Background

Pseudomonas aeruginosa is one of the leading causes of hospital-acquired infections and the most common antimicrobial-resistant pathogens. It is associated with a variety of infections. This study aimed to determine the prevalence of P. aeruginosa and its antimicrobial resistance profile from different clinical specimens at Debre Tabor Comprehensive Referral Hospital (DTCRH).

Methods

A cross-sectional study was conducted from May to July 2022 at DTCRH. Socio-demographic and clinical data were collected using a structured questionnaire. Clinical samples (blood, wound swab, urine, and sputum) were collected from 348 study participants and processed following the standard bacteriological techniques. Antibiotic susceptibility testing was done by the Kirby-Bauer disc diffusion method. Data were entered and analyzed using SPSS version 25 statistical software. Descriptive statistics was used to present the findings of the study.

Results

The prevalence of P.aeruginosa was 74(19.3%). The detection of the isolates was different based on the type of samples that ranged from 0% to 54.5% from sputum and wound swabs, respectively. P.aeruginosa showed resistance against gentamicin at 62.2%, ceftazidime 51.4%, cefepime 50%, amikacin 29.7%, imipenem 28.4% and ciprofloxacin 14.9%. The level of multi-drug resistance (MDR) was 45.9%, and the suspicious extreme-drug resistance (XDR) rate was 9.5%. Being inpatient and wound swab samples were factors associated with the detection of P.aeruginosa from clinical samples.

Conclusion

The antibiotic resistance profile of P. aeruginosa isolates in the present study area was found to be alarming. Actions to minimize the effect of antimicrobial resistance should be strengthened, and further large-scale study should be conducted to find out the main reasons behind antibiotic resistance of P.aeruginosa and other clinically relevant isolates.

Glucose-Induced Enhanced Virulence in Strains of Multidrug-Resistant Pseudomonas aeruginosa Isolated from Diabetic Patients

Pseudomonas aeruginosa is known for its metabolic versatility and uses a variety of substrates; interestingly, glucose is not the favored carbon source. Although glucose is not readily utilized by them, there is a possibility that the increased susceptibility of diabetics to infections with P. aeruginosa is related to the effect of glucose on the expression of virulence genes. The curiosity in understanding the effect of glucose on virulence gene expression in P. aeruginosa and the lacuna of studies in this field prompted us to undertake the current investigation. It included the quantification of various virulence factors and their gene expression upon supplementation with glucose in clinical MDR P. aeruginosa isolates recovered from diabetics. Interestingly, the study observed a remarkable difference in the virulence attributes in the isolates with and without glucose supplementation. External glucose was found to be modulating the QS gene expression, thus altering the elaboration of other virulence factors. Variations in the gene expressions induced by glucose partly explain the increased susceptibility of diabetic patients to P. aeruginosa infections.

Epidemiology and Multidrug Resistance of Pseudomonas aeruginosa and Acinetobacter baumanni Isolated from Clinical Samples in Ethiopia

Background

A. baumannii and P. aeruginosa are important nosocomial pathogens in health-care settings. Both are intrinsically resistant to many drugs and are able to become resistant to the virtually most antimicrobial agents. An increasing prevalence of infections caused by multidrug-resistant isolates has been reported in many countries.

Methods

An institutional-based cross-sectional five-year retrospective study was conducted to assess the antimicrobial resistance trend of P. aeruginosa and A. baumani. 893 A. baumani and 729 P. aeruginosa isolates were included in the study. Conventional method was used for identification and antimicrobial susceptibility was determined by Kirby-Bauer disc-diffusion method. The isolates were from suspected bloodstream infections, wound infections, urinary tract, or surgical site nosocomial infections. Socio-demographic and other variables of interest were collected using a structured check list from a patient record data. Data were analyzed using SPSS version 26 software. P value <0.05 was considered statistically significant.

Results

A total of 1622 A. baumanii and P. aeruginosa were isolated from various clinical specimens recorded from the year 2017-2021. Out of which A. baumanni was 893 (60.6%) and P. aeruginosa was 729 (39.4%). Blood was the major source of the isolates (18.3%), followed by urine (16%), and tracheal aspirate (10.6%). Antimicrobial resistance among A. baumanni over the five years were; ampicillin (86% to 92%), ceftriaxone (66.7% to 82.2%), and ciprofloxacin (58.5% to 66.7%). In P. aeruginosa a significant increase in resistance was seen from 2017 to 2021 to Amoxicillin-clavulanate (74.1% to 84.2%), chloramphenicol (62% to 81.9%), and gentamicin (40% to 44.8%).

Conclusion

A five-year antimicrobial resistance trend analysis of A. baumanni and P. aeruginosa showed increasing multi drug resistance and resistance to highly potent antimicrobial agents in Ethiopia. It should be addressed with infection control measures, surveillance, and alternative new therapeutic strategies to circumvent the spread of multi-drug resistance.

Molecular epidemiology and antimicrobial susceptibility of Pseudomonas spp. and Acinetobacter spp. from clinical samples at Jimma medical center, Ethiopia

Introduction

Pseudomonas aeruginosa (P. aeruginosa) and Acinetobacter baumannii (A. baumannii) can cause difficult-to-treat infections. We characterized molecular epidemiology of ceftazidime-resistant P. aeruginosa and carbapenem-resistant A. baumannii at a tertiary hospital in Ethiopia.

Materials and methods

Non-fermenting gram-negative bacilli (n = 80) isolated from admitted patients were subjected for species identification by MALDI-TOF. Pseudomonas species resistant to ceftazidime or meropenem, and Acinetobacter species resistant to meropenem, or imipenem were selected for whole genome sequencing. DNA extracted with EZ1 Advanced XL instrument (Qiagen, Hilden, Germany) was sequenced on Illumina (HiSeq2500) using libraries prepared by NEXTRA-kits (Illumina). Raw reads were assembled using SPAdes 3.13.0, and assembled genomes were used to query databases for resistome profile and sequence types.

Result

Among Pseudomonas species isolated, 31.7% (13/41), and 7.3% (3/41) were non-susceptible to ceftazidime, and meropenem, respectively. Carbapenem-resistance was 56.4% (22/39) among Acinetobacter species. Moreover, 92% (12/13) of Pseudomonas species non-susceptible to ceftazidime and/or meropenem, and 89.4% (17/19) of Acinetobacter species encoded multiple resistance genes for at least three classes of antimicrobials. The prevalent β - lactamase genes were bla_OXA–486 (53.8%, 7/13), bla_CTX–M–15 (23.0%, 3/13) among Pseudomonas, and bla_GES–11 (57.8%, 11/19) among Acinetobacter. The bla_OXA–51-like β - lactamase, bla_OXA–69 (63.1%, 12/19) was the most prevalent carbapenemase gene among Acinetobacter isolates. Single isolates from both P. aeruginosa, and A. baumannii were detected with the bla_NDM–1. Sequence type (ST)1 A. baumannii and ST274 P. aeruginosa were the prevalent sequence types. A cgMLST analysis of the ST1 A. baumannii isolates showed that they were closely related and belonged to the international clonal complex one (ICC1). Similarly, ST274 P. aeruginosa isolates were clonally related.

Conclusion

The prevalence of MDR isolates of Pseudomonas and Acinetobacter spp. was high. A. baumannii isolates were clonally spreading in the admission wards at the hospital. Emergence of bla_NDM–1 in the intensive care, and surgical wards of the hospital is a severe threat that requires urgent intervention.

Carbapenem-Resistant Organisms Isolated in Surgical Site Infections in Benin: A Public Health Problem

An alarming worldwide increase in antimicrobial resistance is complicating the management of surgical site infections (SSIs), especially in low-middle income countries. The main objective of this study was to describe the pattern of carbapenem-resistant bacteria in hospitalized patients and to highlight the challenge of their detection in Benin. We collected pus samples from patients suspected to have SSIs in hospitals. After bacterial identification by MALDI-TOF mass spectrometry, antimicrobial susceptibility was performed according to the Kirby–Bauer method. Carbapenem-resistant strains were characterized using, successively, the Modified Hodge Test (MHT), the RESIST-5 O.K.N.V.I: a multiplex lateral flow and finally the polymerase chain reaction. Six isolates were resistant to three tested carbapenems and almost all antibiotics we tested but remained susceptible to amikacin. Four (66.7%) of them harbored some ESBL genes (bla_CTX-M-1 and bla_TEM-1). The MHT was positive for Carbapenems but not for Pseudomonas aeruginosa and Acinetobacter baumannii. As surgical antimicrobial prophylaxis, five of the six patients received ceftriaxone. The following carbapenems genes were identified: bla _OXA-48(33.3%, n = 2), bla_NDM (33.3%, n = 2) and bla_VIM (33.3%, n = 2). These findings indicate a need for local and national antimicrobial resistance surveillance and the strengthening of antimicrobial stewardship programs in the country.

Genetic, antimicrobial resistance profile andmortality rates of Acinetobacter baumanniiinfection in Brazil: A systematic reviewMirian

The increase of multidrug-resistant bacteria - including Acinetobacter baumannii (A. baumannii) - has been reported globally. The aim of this systematic review was to determine the risk factors of A. baumannii infection, its resistance profile, reservoirs and mortality rates in Brazil. Data from over 3,000 patients were included. Results suggested that A. baumannii is widely transmitted in Brazil and the endemic clones ST1, ST15, ST 25, ST79, ST162 and ST730 were the most reported; also, blaOXA23, blaOXA51 and blaOXA143 were common resistant genes. The risk factors for A. baumannii infection included the procedure of using invasive devices, previous antibiotic therapy, hemodialysis, comorbidities and higher scores on the Sequential Organ Failure Assessment (SOFA). Two out of five studies identified multidrug resistant A. baumannii to polymyxin. Mortality rates varied between 43.7% to 81%, except for the ST25 strain in which there was a 100% mortality rate. Mortality was associated with sepsis, respiratory infection, septic shock, old age (>60 years) and administration of norepinephrine. Nonetheless, this review highlights the need for more data on A. baumannii infection across Brazil to support public policies aiming to control and prevent the dissemination of this bacteria.

Infections Due to Acinetobacter baumannii-calcoaceticus Complex: Escalation of Antimicrobial Resistance and Evolving Treatment Options

Bacteria within the genus Acinetobacter (principally A. baumannii-calcoaceticus complex [ABC]) are gram-negative coccobacilli that most often cause infections in nosocomial settings. Community-acquired infections are rare, but may occur in patients with comorbidities, advanced age, diabetes mellitus, chronic lung or renal disease, malignancy, or impaired immunity. Most common sites of infections include blood stream, skin/soft-tissue/surgical wounds, ventilator-associated pneumonia, orthopaedic or neurosurgical procedures, and urinary tract. Acinetobacter species are intrinsically resistant to multiple antimicrobials, and have a remarkable ability to acquire new resistance determinants via plasmids, transposons, integrons, and resistance islands. Since the 1990s, antimicrobial resistance (AMR) has escalated dramatically among ABC. Global spread of multidrug-resistant (MDR)-ABC strains reflects dissemination of a few clones between hospitals, geographic regions, and continents; excessive antibiotic use amplifies this spread. Many isolates are resistant to all antimicrobials except colistimethate sodium and tetracyclines (minocycline or tigecycline); some infections are untreatable with existing antimicrobial agents. AMR poses a serious threat to effectively treat or prevent ABC infections. Strategies to curtail environmental colonization with MDR-ABC require aggressive infection-control efforts and cohorting of infected patients. Thoughtful antibiotic strategies are essential to limit the spread of MDR-ABC. Optimal therapy will likely require combination antimicrobial therapy with existing antibiotics as well as development of novel antibiotic classes.