Beta-lactamase Gene Research Articles

Polyclonal Multidrug ESBL-Producing Klebsiella pneumoniae and Emergence of Susceptible Hypervirulent Klebsiella pneumoniae ST23 Isolates in Mozambique.

Globally, antibiotic-resistant Klebsiella spp. cause healthcare-associated infections with high mortality rates, and the rise of hypervirulent Klebsiella pneumoniae (hvKp) poses a significant threat to human health linked to community-acquired infections and increasing non-susceptibility. We investigated the phenotypic and genetic features of 36 Klebsiella isolates recovered from invasive infections at Hospital Central of Maputo in Mozambique during one year. The majority of the isolates displayed multidrug resistance (MDR) (29/36) to cephalosporins, gentamicin, ciprofloxacin, and trimethoprim-sulfamethoxazole but retained susceptibility to amikacin, carbapenems, and colistin. Most isolates were ESBLs-producing (28/36), predominantly carrying the blaCTX-M-15 and other beta-lactamase genes (blaSHV, blaTEM-1, and blaOXA-1). Among the 16 genomes sequenced, multiple resistance genes from different antibiotic classes were identified, with blaCTX-M-15, mostly in the ISEcp1-blaCTX-M-15-orf477 genetic environment, co-existing with blaTEM-1 and aac(3)-IIa in five isolates. Our results highlight the presence of polyclonal MDR ESBL-producing K. pneumoniae from eight sequence types (ST), mostly harbouring distinct yersiniabactin within the conjugative integrative element (ICE). Further, we identified susceptible hvKp ST23, O1-K1-type isolates carrying yersiniabactin (ybt1/ICEKp10), colibactin, salmochelin, aerobactin, and hypermucoid locus (rmpADC), associated with severe infections in humans. These findings are worrying and underline the importance of implementing surveillance strategies to avoid the risk of the emergence of the most threatening MDR hvKp.

Differential effects of wastewater treatment plant effluents on the antibiotic resistomes of diverse river habitats.

Wastewater treatment plants (WWTPs) are key sources of antimicrobial resistance genes (ARGs) that could influence the resistomes of microbial communities in various habitats of the receiving river ecosystem. However, it is currently unknown which habitats are most impacted and whether ARGs, like certain chemical contaminants, could be accumulated or enriched in the river ecosystem. We conducted a systematic metagenomic survey on the antibiotic resistomes of WWTP effluent, four riverine habitats (water, suspended particles, sediment, epilithic biofilm), and freshwater amphipod gut microbiomes. The impact of WWTP effluent on the downstream habitats was assessed in nine Swiss rivers. While there were significant differences in resistomes across habitats, the wastewater resistome was more similar to the resistome of receiving river water than to the resistomes of other habitats, and river water was the habitat most strongly impacted by the WWTPs effluent. The sulfonamide, beta-lactam, and aminoglycoside resistance genes were among the most abundant ARGs in the WWTP effluents, and especially aadA, sul1, and class A beta-lactamase genes showed significantly increased abundance in the river water of downstream compared to upstream locations (p < 0.05). However, this was not the case for the sediment, biofilm, and amphipod gut habitats. Accordingly, evidence for accumulation or enrichment of ARGs through the riverine food web was not identified. Our study suggests that monitoring riverine antimicrobial resistance determinants could be conducted using "co-occurrence" of aadA, sul1, and class A beta-lactamase genes as an indicator of wastewater-related pollution and should focus on the water as the most affected habitat.

Antimicrobial Resistance and Extended-Spectrum Beta-Lactamase Genes in Enterobacterales, Pseudomonas and Acinetobacter Isolates from the Uterus of Healthy Mares.

Antibiotic-resistant bacteria are a growing concern for human and animal health. The objective of this study was to determine the antimicrobial resistance and extended-spectrum beta-lactamase genes in Enterobacterales, Pseudomonas spp. and Acinetobacter spp. isolates from the uterus of healthy mares. For this purpose, 21 mares were swabbed for samples, which were later seeded on blood agar and MacConkey agar. The isolates were identified using MALDI-TOF and the antimicrobial susceptibility test was performed using the Kirby-Bauer technique. To characterize the resistance genes, a polymerase chain reaction (PCR) scheme was performed. Of the isolates identified as Gram-negative, 68.8% were Enterobacterales, represented by E. coli, Enterobacter cloacae, Citrobacter spp., and Klebsiella pneumoniae; 28.1% belonged to the genus Acinetobacter spp.; and 3.1% to Pseudomonas aeruginosa. A 9.3% of the isolates were multidrug-resistant (MDR), presenting resistance to antibiotics from three different classes, while 18.8% presented resistance to two or more classes of different antibiotics. The diversity of three genes that code for ESBL (blaTEM, blaCTX-M and blaSHV) was detected in 12.5% of the strains. The most frequent was blaSHV, while blaTEM and blaCTX-M were present in Citrobacter spp. and Klebsiella pneumoniae. These results are an alarm call for veterinarians and their environment and suggest taking measures to prevent the spread of these microorganisms.

Phylogenetic lineages and antimicrobial resistance determinants of clinical Klebsiella oxytoca spanning local to global scales.

Klebsiella oxytoca is an opportunistic pathogen causing serious nosocomial infections. Knowledge about the population structure and diversity of healthcare-associated K. oxytoca from a genomic standpoint remains limited. Here, we characterized the phylogenetic relationships and genomic characteristics of 20 K. oxytoca sensu stricto isolates recovered from bloodstream infections at the Dartmouth-Hitchcock Medical Center, New Hampshire, USA from 2017 to 2021. Results revealed a diverse population consisting of 15 sequence types (STs) that together harbored 10 variants of the intrinsic beta-lactamase gene bla OXY-2, conferring resistance to penicillins. Similar sets of antimicrobial resistance (AMR) determinants reside in multiple distinct lineages, with no one lineage dominating the local population. To place the New Hampshire K. oxytoca in a broader context, we compared them to 304 publicly available genomes of clinical isolates from 18 countries. This global clinical K. oxytoca sensu stricto population is represented by over 65 STs that together harbored resistance genes against 14 antimicrobial classes, including eight bla OXY-2 variants. Three dominant STs in the global population (ST2, ST176, ST199) circulate across multiple countries and were also present in the New Hampshire population. The global K. oxytoca population is genetically diverse, but there is evidence for broad dissemination of a few lineages carrying distinct set of AMR determinants. Our findings reveal the clinical diversity of K. oxytoca sensu stricto and its importance in surveillance efforts aimed at monitoring the evolution of this drug-resistant nosocomial pathogen. IMPORTANCE The opportunistic pathogen Klebsiella oxytoca has been increasingly implicated in patient morbidity and mortality worldwide, including several outbreaks in healthcare settings. The emergence and spread of antimicrobial resistant strains exacerbate the disease burden caused by this species. Our study showed that clinical K. oxytoca sensu stricto is phylogenetically diverse, harboring various antimicrobial resistance determinants and bla OXY-2 variants. Understanding the genomic and population structure of K. oxytoca is important for international initiatives and local epidemiological efforts for surveillance and control of drug-resistant K. oxytoca.

Epidemiological study of antimicrobial-resistant bacteria in healthy free-ranging bantengs (Bos javanicus) and domestic cattle.

Antimicrobial-resistant microorganisms (ARMs) have been increasing among wild animals. Interactions occurring at the interface between wildlife, humans, and livestock can lead to the transmission of ARMs. Thus, the prevalence of ARMs in wild and domestic animals should be determined to address and prevent this issue. This study aimed to determine the resistance patterns of cefotaxime (CTX)-resistant Escherichia coli and identify the presence of extended-spectrum beta-lactamase (ESBL) genes in ESBL-producing E. coli among a population of wild banteng (Bos javanicus) and domestic cattle kept on farms located close to the Lam Pao non-hunting area, Kalasin province, Thailand. Forty-five fecal samples were taken from wild bantengs inhabiting the Lam Pao non-hunting area in Thailand, alongside 15 samples from domestic cattle. Bacterial culture, triple sugar iron, and motile indole lysine tests were conducted to identify E. coli. A polymerase chain reaction (PCR) was conducted for specific confirmation. MacConkey agar supplemented with 2 μg/mL of CTX was used to identify CTX-resistant E. coli, which would be used to identify ESBL production based on a double-disk synergy test. Extended-spectrum beta-lactamase-producing samples were subjected to disk diffusion tests to determine resistant patterns, and the sizes of PCR bands and DNA sequencing were used to differentiate ESBL gene types. All samples tested positive for E. coli. Forty-five isolates from 15 banteng samples and three isolates from one domestic cattle sample displayed CTX-resistant and ESBL-producing traits. The banteng and domestic cattle populations exhibited nine and three distinct resistant patterns, respectively. The PCR results indicated that the banteng isolates harbored the following genes: Cefotaxime-M1 (n = 38), CTX-M9 (n = 5), and the SHV group (n = 2). All three isolates from the domestic cattle sample contained the CTX-M1 gene. Classification of ESBL genes based on the DNA sequences of the banteng isolates showed the characteristics of CTX-M15 (n = 20), CTX-M55 (n = 6), CTX-M14 (n = 5), and CTX-M79 (n = 1). The three domestic cattle isolates exhibited the characteristics of CTX-M15, CTX-M55, and CTX-M79. Despite no previous antibiotic applications, approximately one-third of the banteng samples displayed CTX resistance, indicating ARM contamination within the ecosystem. The similarity in ESBL genes between the banteng and domestic cattle populations suggests potential gene transmissions between these animal groups. However, the initial source of ARMs remains unclear, as the banteng population exhibited more ESBL genes than the domestic cattle, suggesting the possibility of multiple ARM sources. These findings raise concerns because the banteng population inhabits an area that is an important source of freshwater and nourishes the entire north-east region of Thailand and other South-east Asian countries, including Laos, Cambodia, and Southern Vietnam.

Characterization of Carbapenemase- and ESBL-Producing Gram-Negative Bacilli Isolated from Patients with Urinary Tract and Bloodstream Infections.

A total of 199 Gram-negative bacterial isolates from urinary tract infections and 162 from bloodstream infections were collected from 12 healthcare systems throughout the United States between May 2021 and August 2022. The isolates, phenotypically non-susceptible to 2nd or 3rd generation cephalosporins or carbapenems, were characterized through antimicrobial susceptibility testing and whole genome sequence analysis to obtain a broad snapshot of beta-lactamase-mediated resistance among these two sample types. Overall, 23 different carbapenemase genes were detected among 13 species (20.5% of isolates). The blaKPC-3 and blaKPC-2 subtypes were the most common carbapenemase genes identified, followed by blaNDM and the co-carriage of two different blaOXA carbapenemases by Acinetobacter baumannii isolates. All carbapenemase-producing A. baumannii isolates were mCIM negative. Extended-spectrum beta-lactamase genes were identified in 66.2% of isolates; blaCTX-M-15 was the most common. AmpC genes, both plasmid and chromosomal, were detected in 33.2% of isolates. Importantly, 2.8%, 8.3%, and 22.2% of blaKPC-positive organisms were susceptible to ertapenem, imipenem, and meropenem, respectively. The correlation between broth microdilution and disk diffusion results was high for most drugs except cefepime, where the detection of resistance was statistically lower by disk diffusion. Thus, there were gaps in the accuracy of susceptibility testing for some mechanisms of resistance.

Characteristics and genomic epidemiology of colistin-resistant Enterobacterales from farmers, swine, and hospitalized patients in Thailand, 2014–2017

BackgroundColistin is one of the last resort therapeutic options for treating carbapenemase-producing Enterobacterales, which are resistant to a broad range of beta-lactam antibiotics. However, the increased use of colistin in clinical and livestock farming settings in Thailand and China, has led to the inevitable emergence of colistin resistance. To better understand the rise of colistin-resistant strains in each of these settings, we characterized colistin-resistant Enterobacterales isolated from farmers, swine, and hospitalized patients in Thailand.MethodsEnterobacterales were isolated from 149 stool samples or rectal swabs collected from farmers, pigs, and hospitalized patients in Thailand between November 2014–December 2017. Confirmed colistin-resistant isolates were sequenced. Genomic analyses included species identification, multilocus sequence typing, and detection of antimicrobial resistance determinants and plasmids.ResultsThe overall colistin-resistant Enterobacterales colonization rate was 26.2% (n = 39/149). The plasmid-mediated colistin-resistance gene (mcr) was detected in all 25 Escherichia coli isolates and 9 of 14 (64.3%) Klebsiella spp. isolates. Five novel mcr allelic variants were also identified: mcr-2.3, mcr-3.21, mcr-3.22, mcr-3.23, and mcr-3.24, that were only detected in E. coli and Klebsiella spp. isolates from farmed pigs.ConclusionOur data confirmed the presence of colistin-resistance genes in combination with extended spectrum beta-lactamase genes in bacterial isolates from farmers, swine, and patients in Thailand. Differences between the colistin-resistance mechanisms of Escherichia coli and Klebsiella pneumoniae in hospitalized patients were observed, as expected. Additionally, we identified mobile colistin-resistance mcr-1.1 genes from swine and patient isolates belonging to plasmids of the same incompatibility group. This supported the possibility that horizontal transmission of bacterial strains or plasmid-mediated colistin-resistance genes occurs between humans and swine.

Characterization of Beta-Lactam Resistome of Escherichia coli Causing Nosocomial Infections.

Nosocomial infections caused by Escherichia coli pose significant therapeutic challenges due to the high expression of genes encoding antimicrobial drug resistance. In this study, we investigated the conformation of the beta-lactam resistome responsible for the specific pattern of resistance against beta-lactam antibiotics. A total of 218 Escherichia coli strains were isolated from in-hospital patients diagnosed with nosocomial infections, obtained from various sources such as urine (n = 49, 22.48%), vaginal discharge (n = 46, 21.10%), catheter tips (n = 14, 6.42%), blood (n = 13, 5.96%), feces (n = 12, 5.50%), sputum (n = 11, 5.05%), biopsies (n = 8, 3.67%), cerebrospinal fluid (n = 2, 0.92%) and other unspecified discharges (n = 63, 28.90%). To characterize the beta-lactam resistome, all strains were subjected to antibiotic dilution tests and grown in beta-lactam antibiotics supplemented with Luria culture medium. Subsequently, multiplex PCR and next-generation sequencing were conducted. The results show a multi-drug-resistance phenotype, particularly against beta-lactam drugs. The primary determinant of this resistance was the expression of the blaTEM gene family, with 209 positive strains (95.87%) expressing it as a single gene (n = 47, 21.6%) or in combination with other genes. Common combinations included blaTEM + blaCTX (n = 42, 19.3%), blaTEM + blaCTX + blaSHV (n = 13, 6%) and blaTEM + blaCTX + blaBIL (n = 12, 5.5%), among others. The beta-lactam resistome of nosocomial Escherichia coli strains isolated from inpatients at the "October first" Regional Hospital of ISSSTE was predominantly composed of members of the blaTEM gene family, expressed in various configurations along with different members of other beta-lactamase gene families.

Prevalence, clonal diversity, and antimicrobial resistance of hypervirulent Klebsiella pneumoniae and Klebsiella variicola clinical isolates in northern Japan

Hypervirulent Klebsiella pneumoniae (hvKp) and Klebsiella variicola (hvKv) cause hospital/community-acquired infections, often associated with antimicrobial resistance (AMR). This study aimed to investigate the molecular epidemiology of hvKp and hvKv in northern Japan. A total of 500 K. pneumoniae and 421 K. variicola clinical isolates collected from August to December 2021 were studied. Prevalence of virulence factor-encoding genes, wzi sequence and associated K/KL type, sequence type (ST), and beta-lactamases and their types were characterized. Any virulence gene (rmpA, rmpA2, peg-344, iucA, iutA, and iroB) and/or magA was detected in 25% (n=125) of K. pneumoniae and 1% (n=5) of K. variicola. Among these hvKp/hvKv, 22 wzi types (18 and 4 types, respectively) and 24 STs (20 and 4 STs, respectively) were identified. Sequence types of hvKp were classified into some clonal groups (CGs), among which CG35, including six STs, was the most common (n=59; 47%), followed by CG23, and CG65. ST268 (CG35) associated with wzi95-K20 or wzi720 was the dominant lineage (n=43, 34%), while K1:ST23/ST249 and K2:ST65/ST86 accounted for 26% and 13% of hvKp, respectively. Extended-spectrum beta-lactamase (ESBL) genes (blaCTX-M-2, blaCTX-M-3, blaCTX-M-15, and blaCTX-M-27) were detected in only ST23 and CG35 (ST268 and ST412) hvKp. No isolate was resistant to carbapenems, without detection of the ESBL gene in K. variicola. Phylogenetically, wzi was differentiated into two main clusters of K. pneumoniae and K. variicola. A major clonal group CG347 was identified in K. variicola. Clonal structures were revealed for hvKp and hvKv clinical isolates with their AMR status in northern Japan.

Extended-spectrum beta-lactamase genes among Gram negative bacilli isolates from Egyptian children with diarrhea

Extended-spectrum beta-lactamase genes among Gram negative bacilli isolates from Egyptian children with diarrhea

Genomic Characterization of Salmonella Isangi: A Global Perspective of a Rare Serovar.

Salmonella Isangi is an infrequent serovar that has recently been reported in several countries due to nosocomial infections. A considerable number of reports indicate Salmonella Isangi multidrug resistance, especially to cephalosporins, which could potentially pose a risk to public health worldwide. Genomic analysis is an excellent tool for monitoring the emergence of microorganisms and related factors. In this context, the aim of this study was to carry out a genomic analysis of Salmonella Isangi isolated from poultry in Brazil, and to compare it with the available genomes from the Pathogen Detection database and Sequence Read Archive. A total of 142 genomes isolated from 11 different countries were investigated. A broad distribution of extended-spectrum beta-lactamase (ESBL) genes was identified in the Salmonella Isangi genomes examined (blaCTX-M-15, blaCTX-M-2, blaDHA-1, blaNDM-1, blaOXA-10, blaOXA-1, blaOXA-48, blaSCO-1, blaSHV-5, blaTEM-131, blaTEM-1B), primarily in South Africa. Resistome analysis revealed predicted resistance to aminoglycoside, sulfonamide, macrolide, tetracycline, trimethoprim, phenicol, chloramphenicol, and quaternary ammonium. Additionally, PMQR (plasmid-mediated quinolone resistance) genes qnr19, qnrB1, and qnrS1 were identified, along with point mutations in the genes gyrAD87N, gyrAS83F, and gyrBS464F, which confer resistance to ciprofloxacin and nalidixic acid. With regard to plasmids, we identified 17 different incompatibility groups, including IncC, Col(pHAD28), IncHI2, IncHI2A, IncM2, ColpVC, Col(Ye4449), Col156, IncR, IncI1(Alpha), IncFIB (pTU3), Col(B5512), IncQ1, IncL, IncN, IncFIB(pHCM2), and IncFIB (pN55391). Phylogenetic analysis revealed five clusters grouped by sequence type and antimicrobial gene distribution. The study highlights the need for monitoring rare serovars that may become emergent due to multidrug resistance.

Abundance and prevalence of ESBL coding genes in patients undergoing first line eradication therapy for Helicobacter pylori.

The spread of extended-spectrum beta-lactamases (ESBLs) in nosocomial and community-acquired enterobacteria is an important challenge for clinicians due to the limited therapeutic options for infections that are caused by these organisms. Here, we developed a panel of ESBL coding genes, evaluated the abundance and prevalence of ESBL encoding genes in patients undergoing H. pylori eradication therapy, and summarized the effects of eradication therapy on functional profiles of the gut microbiome. To assess the repertoire of known beta lactamase (BL) genes, they were divided into clusters according to their evolutionary relation. Primers were designed for amplification of cluster marker regions, and the efficiency of this amplification panel was assessed in 120 fecal samples acquired from 60 patients undergoing H. pylori eradication therapy. In addition, fecal samples from an additional 30 patients were used to validate the detection efficiency of the developed ESBL panel. The presence for majority of targeted clusters was confirmed by NGS of amplification products. Metagenomic sequencing revealed that the abundance of ESBL genes within the pool of microorganisms was very low. The global relative abundances of the ESBL-coding gene clusters did not differ significantly among treatment states. However, at the level of each cluster, classical ESBL producers such as Klebsiella sp. for blaOXY (p = 0.0076), Acinetobacter sp. for blaADC (p = 0.02297) and others, differed significantly with a tendency to decrease compared to the pre- and post-eradication states. Only 13 clusters were common across all three datasets, suggesting a patient-specific distribution profile of ESBL-coding genes. The number of AMR genes detected in the post-eradication state was higher than that in the pre-eradication state, which could be attributed, at least in part, to the therapy. This study demonstrated that the ESBL screening panel was effective in targeting ESBL-coding gene clusters from bacterial DNA and that minor differences exist in the abundance and prevalence of ESBL-coding gene levels before and after eradication therapy.

Molecular epidemiology of antimicrobial resistance in central africa: A systematic review.

In Central Africa, it is difficult to tackle antibiotic resistance, because of a lack of data and information on bacterial resistance, due to the low number of studies carried out in the field. To fill this gap, we carried out a systematic review of the various studies, and devised a molecular epidemiology of antimicrobial resistance from humans, animals and the environmental samples. A systematic search of all publications from 2005 to 2020 on bacterial resistance in Central Africa (Gabon, Cameroon, Democratic Republic of Congo, Central African Republic, Chad, Republic of Congo, Equatorial Guinea, São Tomé and Príncipe, Angola) was performed on Pubmed, Google scholar and African Journals Online (AJOL). All circulating resistance genes, prevalence and genetic carriers of these resistances were collected. The study area was limited to the nine countries of Central Africa. A total of 517 studies were identified through a literature search, and 60 studies carried out in eight countries were included. Among all articles included, 43 articles were from humans. Our study revealed not only the circulation of beta-lactamase and carbapenemase genes, but also several other types of resistance genes. To finish, we noticed that some studies reported mobile genetic elements such as integrons, transposons, and plasmids. The scarcity of data poses difficulties in the implementation of effective strategies against antibiotic resistance, which requires a health policy in a 'One Health' approach.

Resistance profiles and genotyping of extended-spectrum beta-lactamase (ESBL) -producing and non-ESBL-producing E. coli and Klebsiella from retail market fishes.

Studies on antimicrobial resistance (AMR) profiles and epidemiological affirmation for AMR transmission are limited in fisheries and aquaculture settings. Since 2015, based on Global Action Plan on AMR by World Health Organization (WHO) and World Organization for Animal Health (OIE), several initiatives have been under taken to enhance the knowledge, skills and capacity to establish AMR trends through surveillance and strengthening of epidemiological evidence. The focus of this study was to determine the prevalence of antimicrobial resistance (AMR), its resistance profiles and molecular characterization with respect to phylogroups, antimicrobial resistance genes (ARGs), virulence genes (VGs), quaternary ammonium compounds resistance (QAC) genes and plasmid typing in retail market fishes. Pulse field gel electrophoresis (PFGE) to understand the genetic lineage of the two most important Enterobacteriaceae members, E. coli and Klebsiella sp. was performed. 94 fish samples were collected from three different sites viz., Silagrant (S1), Garchuk (S2) and North Guwahati Town Committee (NGTC) Region (S3) in Guwahati, Assam. Out of the 113 microbial isolates from the fish samples, 45 (39.82%) were E. coli; 23 (20.35%) belonged to Klebsiella genus. Among E. coli, 48.88% (n=22) of the isolates were alerted by the BD Phoenix M50 instrument as ESBL, 15.55% (n=7) as PCP and 35.55% (n=16) as non-ESBL. E. coli (39.82%) was the most prevalent pathogen among the Enterobacteriaceae members screened and showed resistance to ampicillin (69%) followed by cefazoline (64%), cefotaxime (49%) and piperacillin (49%). In the present study, 66.66% of E. coli and 30.43% of Klebsiella sp. were categorized as multi drug resistance (MDR) bacteria. CTX-M-gp-1, with CTX-M-15 variant (47%), was the most widely circulating beta-lactamase gene, while other ESBL genes blaTEM (7%), blaSHV (2%) and blaOXA-1-like (2%) were also identified in E. coli. Out of the 23 isolates of Klebsiella, 14(60.86%) were ampicillin (AM)-resistant (11(47.82%) K. oxytoca, 3(13.04%) K. aerogenes), whereas 8(34.78%) isolates of K. oxytoca showed intermediate resistance to AM. All Klebsiella isolates were susceptible to AN, SCP, MEM and TZP, although two K. aerogenes were resistant to imipenem. DHA and LAT genes were detected, respectively, in 7(16%) and 1(2%) of the E. coli strains while a single K. oxytoca (4.34%) isolate carried MOX, DHA and blaCMY-2 genes. The fluoroquinolone resistance genes identified in E. coli included qnrB (71%), qnrS (84%), oqxB (73%) and aac(6)-Ib-cr (27%); however, in Klebsiella, these genes, respectively, had a prevalence of 87%, 26%, 74% and 9%. The E. coli isolates belonged to phylogroup A(47%), B1(33%) and D(14%). All of the 22(100%) ESBL E. coli had chromosome-mediated disinfectant resistance genes viz., ydgE, ydgF, sugE(c), mdfA while 82% of ESBL E. coli had emrE. Among the non-ESBL E. coli isolates, 87% of them showed the presence of ydgE, ydgF and sugE(c) genes, while 78% of the isolates had mdfA and 39% had emrE genes respectively. 59% of the ESBL and 26% of the non-ESBL E. coli had showed the presence of qacEΔ1. The sugE(p) was present in 27% of the ESBL-producing E. coli and in 9% of non-ESBL isolates. Out of the 3 ESBL-producing Klebsiella isolates, 2(66.66%) K. oxytoca isolates were found harboring plasmid-mediated qacEΔ1 gene while one (33.33%) K. oxytoca isolate had sugE(p) gene. IncFI was the most prevalent plasmid type detected in the isolates studied, with A/C (18%), P (14%), X, Y (9% each) and I1-Iγ (14%, 4%). 50% (n=11) of the ESBL and 17% (n=4) of the non-ESBL E. coli isolates harboured IncFIB and 45% (n=10) ESBL and one (4.34%) non-ESBL E. coli isolates harboured IncFIA. Dominance of E. coli over other Enterobacterales and diverse phylogenetic profiles of E. coli and Klebsiella sp. suggests the possibility of contamination and this may be due to compromised hygienic practices along the supply chain and contamination of aquatic ecosystem. Continuous surveillance in domestic markets must be a priority in addressing antimicrobial resistance in fishery settings and to identify any unwarranted epidemic clones of E. coli and Klebsiella that can challenge public health sector.

Screening for Resistant Bacteria, Antimicrobial Resistance Genes, Sexually Transmitted Infections and Schistosoma spp. in Tissue Samples from Predominantly Vaginally Delivered Placentae in Ivory Coast and Ghana.

Medical complications during pregnancy have been frequently reported from Western Africa with a particular importance of infectious complications. Placental tissue can either become the target of infectious agents itself, such as, e.g., in the case of urogenital schistosomiasis, or be subjected to contamination with colonizing or infection-associated microorganisms of the cervix or the vagina during vaginal delivery. In the retrospective cross-sectional assessment presented here, the quantitative dimension of infection or colonization with selected resistant or pathogenic bacteria and parasites was regionally assessed. To do so, 274 collected placental tissues from Ivory Coastal and Ghanaian women were subjected to selective growth of resistant bacteria, as well as to molecular screening for beta-lactamase genes, Schistosoma spp. and selected bacterial causative agents of sexually transmitted infections (STI). Panton-Valentine-negative methicillin-resistant Staphylococcus aureus (MRSA) was grown from 1.8% of the tissue samples, comprising the spa types t008 and t688, as well as the newly detected ones, t12101 (n = 2) and t12102. While the culture-based recovery of resistant Enterobacterales and nonfermentative rod-shaped Gram-negative bacteria failed, molecular assessments confirmed beta-lactamase genes in 31.0% of the samples with multiple detections of up to four resistance genes per sample and blaCTX-M, blaIMP, blaGES, blaVIM, blaOXA-58-like, blaNDM, blaOXA-23-like, blaOXA-48-like and blaKPC occurring in descending order of frequency. The beta-lactamase genes blaOXA-40/24-like, blaNMC_A/IMI, blaBIC, blaSME, blaGIM and blaDIM were not detected. DNA of the urogenital schistosomiasis-associated Schistosoma haematobium complex was recorded in 18.6% of the samples, but only a single positive signal for S. mansoni with a high cycle-threshold value in real-time PCR was found. Of note, higher rates of schistosomiasis were observed in Ghana (54.9% vs. 10.3% in Ivory Coast) and Cesarean section was much more frequent in schistosomiasis patients (61.9% vs. 14.8% in women without Schistosoma spp. DNA in the placenta). Nucleic acid sequences of nonlymphogranuloma-venereum-associated Chlamydia trachomatis and of Neisseria gonorrhoeae were recorded in 1.1% and 1.9% of the samples, respectively, while molecular attempts to diagnose Treponema pallidum and Mycoplasma genitalium did not lead to positive results. Molecular detection of Schistosoma spp. or STI-associated pathogens was only exceptionally associated with multiple resistance gene detections in the same sample, suggesting epidemiological distinctness. In conclusion, the assessment confirmed considerable prevalence of urogenital schistosomiasis and resistant bacterial colonization, as well as a regionally expected abundance of STI-associated pathogens. Continuous screening offers seem advisable to minimize the risks for the pregnant women and their newborns.

Genomic and functional portrait of multidrug-resistant, hydrogen sulfide (H2S)-producing variants of Escherichia coli.

Atypical Escherichia coli forms exhibit unusual characteristics compared to typical strains. The H2S-producing variants of some atypical E. coli strains cause a wide range of illnesses in humans and animals. However, there are sparse reports on such strains worldwide. We performed whole-genome sequencing (WGS) and detailed characterization of four H2S-producing E. coli variants from poultry and human clinical sources in Dhaka, Bangladesh. All four isolates were confirmed as E. coli using biochemical tests and genomic analysis, and were multidrug-resistant (MDR). WGS analysis including an additional Chinese strain, revealed diverse STs among the five H2S-producing E. coli genomes, with clonal complex ST10 being detected in 2 out of 5 genomes. The predominant phylogroup detected was group A (n = 4/5). The blaTEM1B (n = 5/5) was the most predominant extended-spectrum beta-lactamase (ESBL) gene, followed by different alleles of blaCTX-M (blaCTX-M -55,-65,-123; n = 3/5). Multiple plasmid replicons were detected, with IncX being the most common. One E. coli strain was classified as enteropathogenic E. coli. The genomes of all five isolates harbored five primary and four secondary function genes related to H2S production. These findings suggest the potential of these isolates to cause disease and spread antibiotic resistance. Therefore, such atypical E. coli forms should be included in differential diagnosis to understand the pathogenicity, antimicrobial resistance and evolution of H2S-producing E. coli.

The Emergence of Carbapenem- and Colistin-Resistant Enterobacteria in Senegal.

Antibiotic resistance is a public health problem. The emergence of carbapenemase-producing Enterobacterales (CPE) infections is a concern, particularly in Senegal. (1) Methods: Between January 2019 and July 2022, 240 isolates of enterobacteria resistant to third-generation cephalosporins and imipenem from biological samples from Fann Hospital (Dakar) and Hôpital Paix (Ziguinchor) were selected. The isolates were identified by MALDI-TOF mass spectrometry, and susceptibility tests were performed by the disk diffusion method. Antibiotic-resistance genes for class A beta-lactamases, carbapenemases, and plasmid resistance to colistin resistance (mcr-1-8) were screened by RT-PCR. (2) Results: The 240 enterobacteria were composed of: Escherichia coli (60.83%), Klebsiella pneumoniae (21.67%), Enterobacter cloacae (13.75%), Citrobacter freundii (2.08%), Serratia marcescens (0.83%), Klebsiella aerogenes (0.42%), and Proteus mirabilis (0.42%). Class A beta-lactamase genes were found in 229 isolates (70.41% blaTEM, 37.5% blaSHV, 83.75% blaCTX-A, and 0.42% blaCTX-B). The carbapenemase genes blaOXA-48 and blaNDM were found in 25 isolates, including 14 isolates with blaOXA-48, 13 isolates with blaNDM, and 2 isolates with both genes simultaneously. The mcr-8 gene was found in one isolate of E. cloacae. (3) Conclusions: The epidemiology of antibiotic-resistance genes in enterobacteria in Senegal shows the emergence of CPEs. This phenomenon is worrying, and rigorous surveillance is necessary to avoid further spread.

The Presence of Virulent and Multidrug-Resistant Clones of Carbapenem-Resistant Klebsiella pneumoniae in Southeastern Brazil.

The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) represents an urgent threat to global public health due to the limited therapeutic options available to control this pathogen. This study aims to analyze the molecular epidemiology, antimicrobial resistance and virulence profile of CRKP isolated from patients at hospitals in Southeastern Brazil. KPC and other beta-lactamase genes were detected in all strains, which were also multidrug-resistant (MDR). In addition, 11 strains showed resistance to last-resort antimicrobials, such as colistin and tigecycline. MLST analysis revealed eight different sequence types (ST11, ST37, ST147, ST340, ST384, ST394, ST437, and ST628), being two (ST628 and ST394) reported for the first time in Brazil. Strains belonging to the clonal complex 258 (CC258) "high-risk clones" were prevalent in this study. The Galleria mellonella model showed the emergence of virulent CRKP strains in the healthcare environment and, suggests that colistin-resistant strains were associated with higher virulence. This study shows the presence of virulent CRKP-MDR strains in hospitals across Southeastern Brazil, and draws attention to the presence of highly virulent emerging CRKP-MDR ST628 strains, showing that virulent and resistant clones can emerge quickly, requiring constant monitoring.

Targeted metagenomics using bait-capture to detect antibiotic resistance genes in retail meat and seafood.

Metagenomics analysis of foods has the potential to provide comprehensive data on the presence and prevalence of antimicrobial resistance (AMR) genes in the microbiome of foods. However, AMR genes are generally present in low abundance compared to other bacterial genes in the food microbiome and consequently require multiple rounds of in-depth sequencing for detection. Here, a metagenomics approach, using bait-capture probes targeting antimicrobial resistance and plasmid genes, is used to characterize the resistome and plasmidome of retail beef, chicken, oyster, shrimp, and veal enrichment cultures (n = 15). Compared to total shotgun metagenomics, bait-capture required approximately 40-fold fewer sequence reads to detect twice the number of AMR gene classes, AMR gene families, and plasmid genes across all sample types. For the detection of critically important extended spectrum beta-lactamase (ESBL) genes the bait capture method had a higher overall positivity rate (44%) compared to shotgun metagenomics (26%), and a culture-based method (29%). Overall, the results support the use of bait-capture for the identification of low abundance genes such as AMR genes from food samples.

Characterization of blaTEM and blaCTX-M beta-lactam resistance genes in chronic rhinosinusitis

BackgroundChronic sinusitis is one of the most challenging health problems of contemporary society. Although several treatment methods have been defined, a comprehensive understanding of the underlying causes (e.g., antibiotic resistance) is still elusive. The aim of this study was to characterize two of the main extended-spectrum beta-lactamase genes—i.e., blaTEM and blaCTX-M genes—and investigate antimicrobial resistance in bacteria isolated from chronic sinusitis. Samples from 70 chronic sinusitis patients and 20 healthy individuals (controls) were analyzed for the presence of blaTEM and blaCTX-M resistance genes using the polymerase chain reaction (PCR) test, followed by gene sequence analysis.ResultsPhenotypic and genotypic beta-lactam resistance was observed in 58.7% and 61.54% of the gram-negative isolates, respectively, with 38.46% carrying the blaTEM gene and 34.62% harboring the blaCTX-M gene. Sequencing data indicated high heterogeneity in blaCTX-M genes (69–100% similarity to reported sequences) and lower heterogeneity in blaTEM genes (93–99%).ConclusionBroad-spectrum beta-lactam resistance is a major pathogenesis factor in chronic rhinosinusitis, and careful consideration is required for antimicrobial therapy. High blaCTX-M heterogeneity could mean high horizontal transfer rate of this gene and warrant a surveillance program.