Β-lactamase Production Research Articles

Post-Transplant Fecal Carriage of Antibiotic Resistant and B-Lactamases-Producing Enterobacteriales among Renal Transplant Recipients.

The intestinal colonization and transmission of antibiotic-resistant Enterobacteriales to renal transplant recipients may pose a threat to them because they are profoundly immunocompromised and vulnerable to infection. Hence, it is crucial to identify these antibiotic-resistant fecal Enterobacteriales harboring high-risk populations. The objective of this study was to determine antibiotic resistance as well as β-lactamases production in fecal Enterobacteriales among renal transplant recipients. The stool samples, one collected from each transplant recipient, were processed for isolation and identification of Enterobacteriales and were tested for their antibiotic susceptibility, extended-spectrum β-lactamase, and metallo-β-lactamase production by standard methods. A total of 103 Enterobacteriales comprising of Escherichia coli (86.4%), Klebsiella species (11.7%), and Citrobacter species (1.9%) were isolated and more than 60% of the E. coli were found resistant to ceftazidime and ciprofloxacin and around half of the Klebsiella species were resistant to ceftazidime and fluroquinolones. Theextended-spectrum β-lactamase production was seen in 3.4% and 8.3% and metallo-β-lactamase production in 24.7% and 33.3% of E. coli and Klebsiella species, respectively. The high proportion of β-lactamase-producers were resistant to piperacillin-tazobactam, meropenem, gentamicin, and amikacin than β-lactamases non-producers. Since the antibiotic resistance is higher in fecal Enterobacteriales, eachrenal transplant recipient should be screened for these highly resistant intestinal colonizers after transplantation in order to prevent infections and toreduce the rate of transplant failure due to infections.

Multi- and extensively drug resistant Escherichia coli isolated from South African children under 5 years old with diarrhoea

BackgroundGlobally, millions of children die as a result of diarrhoea and/or antimicrobial resistant infections. Diarrhoeagenic Escherichia coli (DEC) are responsible for a substantial proportion of cases of diarrhoea in South Africa and sub-Saharan Africa. Effective treatments (including the use of antimicrobials) are therefore essential. MethodologyE. coli isolated from children under the age of five were subjected to antimicrobial susceptibility testing using the Vitek 2® compact automated system (bioMérieux Inc., France) and categorized as multidrug or extensively drug resistant (MDR or XDR). ResultsAlmost all isolates (164/166, 98.8 %) were categorized as MDR with 4.9 % (9/166) categorized as XDR. The majority of isolates (153/166, 92.2 %) were also phenotypically classified as extended-spectrum β-lactamase (ESBL) producers. More than half of these isolates (78/153, 51.0 %) were subjected to PCR for genes associated with ESBL production. More than half (45/78, 57.7 %) of the isolates tested were PCR positive for at least one ESBL gene or gene group and 11.5 % (9/78) were positive for two ESBL genes or gene groups. DiscussionThere is a need to strengthen antimicrobial resistance surveillance in South Africa and improve infection prevention and control measures. There is also a need to review the current South African Treatment Guidelines as outlined by the South African Essential Drugs Programme.

Epidemiology and microbiology of catheter-associated urinary tract infections: A 14-year surveillance study at a tertiary care center in Lebanon

BackgroundCatheter-associated urinary tract infections (CAUTIs) are the most common device-associated healthcare-acquired infections and pose a significant burden on patients and healthcare systems worldwide. However, there is a paucity of data on CAUTI epidemiology and microbiology in the Middle East and North Africa (MENA) region, including Lebanon. MethodsThis 14-year retrospective cohort study was conducted at a tertiary care center in Lebanon. It analyzed data on all adult patients diagnosed with CAUTI between January 2009 and December 2022 in intensive care units (ICUs) and between June 2011 and December 2022 in regular units. Incidence rates, urinary catheter utilization ratios, and microbiological profiles were collected and analyzed. ResultsA total of 620 CAUTI cases were identified during the study period. The overall CAUTI rate was 2.4 per 1000 catheter-days, with higher rates in ICUs (3.2 per 1000 catheter-days) compared to regular units (1.4 per 1000 catheter-days). No significant changes in the rates were noted despite implementing many interventions. The most common pathogens were Gram-negative bacteria, with Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae being predominant. Multidrug-resistant organisms represented 48% of all isolates. Enterobacterales were largely extended-spectrum β-lactamase (ESBL) producing, and most Acinetobacter baumannii isolates showed multidrug resistance. ConclusionsThis study provides important insights into CAUTI epidemiology and microbiology in a tertiary care center in Lebanon, addressing the knowledge gap in this area in the MENA region. Despite implementing prevention measures, CAUTI rates remained stable over the 14-year period. The findings highlight the need for continuous improvement in infection prevention practices, diagnostic stewardship, and antimicrobial stewardship, especially given the rising threat of antimicrobial resistance. These results can serve as a guide for the development of targeted preventive strategies to reduce the burden of CAUTIs, particularly in low- and middle-income countries where antimicrobial resistance is a major issue.

Study of Antibiotic Resistance in ESKAPE Bacteria Using β-lactamase and ESBL Genes

Background: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species, collectively known as ESKAPE bacteria, pose a significant threat in healthcare settings due to their increasing antibiotic resistance. Understanding the mechanisms underlying their resistance is crucial for developing effective therapeutic strategies. Methods: This study aimed to investigate the phenotypic and genotypic properties of β-lactamase enzymes in ESKAPE bacteria isolated from ulcer infections. Clinical specimens were collected from patients with various ulcer diseases, and bacterial isolates were identified using standard bacteriological methods and the Vitek-2 automated system. DNA extraction, polymerase chain reaction (PCR), and antibiotic susceptibility testing using the Kirby-Bauer disk diffusion method were performed. The presence of specific β-lactamase genes (blaKPC, blaTEM, blaCTX-M, and blaAMPC) was examined through molecular techniques. Results: Among the 104 clinical specimens collected, 88% yielded positive cultures, with Gram-negative bacteria predominating. Antibiotic susceptibility testing revealed high resistance rates, particularly to β-lactam antibiotics, among ESKAPE isolates. Molecular analysis identified the presence of extended-spectrum β-lactamases (ESBLs) in all isolates, with blaKPC and blaTEM being the most prevalent β-lactamase genes. Notably, blaKPC was detected in 72% of E. cloacae, 13.3% of S. aureus, 33.33% of Klebsiella pneumoniae, 50% of Pseudomonas aeruginosa, 0% of E. faecium, and 100% of A. baumannii isolates. Similarly, blaCTX-M and blaAMPC genes showed distinct distribution patterns across the different species. Conclusion: The study highlights the widespread presence of ESBL-producing ESKAPE bacteria in ulcer infections and underscores the importance of molecular techniques for accurate detection of β-lactamase production.

A systematic review and meta-analysis of carbapenem resistance and its possible treatment options with focus on clinical Enterobacteriaceae: Thirty years of development in Pakistan

BackgroundCarbapenem resistance is epidemic worldwide, these last resort antimicrobials are listed in the WHO ‘watch group’ with higher resistance potential. During the years 2017-18 Pakistan Antimicrobial Resistance Surveillance System reported an increase in carbapenem resistance. However, a comprehensive information on prevalence and molecular epidemiology of carbapenem resistance in Pakistan is not available. This systematic review and meta-analysis is aimed to report the current carbapenem resistance situation in Pakistan and its treatment options. MethodsIn this systematic review and meta-analysis, we investigated the pooled prevalence (PPr) of carbapenem resistance in Enterobacteriaceae and non-Enterobacteriaceae by organizing available data, from Web of Science and PubMed by April 2, 2020, in various groups and subgroups including species, years, provinces, extended spectrum β-lactamase production, clinical presentation, carbapenemase and metallo-β-lactamase production, and New Delhi metallo-β-lactamase (NDM) prevalence. Literature review was updated for the studies publisehd by December 07, 2023. Moreover, we descriptively reviewed the molecular epidemiology of carbapenem resistance in Enterobacteriaceae and non-Enterobacteriaceae in Pakistan. Lastly, we statistically explored different treatment options available for carbapenem resistant infections. We used R package ‘metafor’ for performing meta-analysis and influence diagnostics and determining treatment options. ResultsFrom two academic databases Web of Science and PubMed we identified 343 studies. Eighty-eight studies were selected for the systematic review and meta-analysis. Seventy-four studies were selected for phenotypic analysis, 36 for genotypic analysis, and 31 for available treatment options. PPr-ID of 12% [0.12 (0.07, 0.16)] was observed for phenotypic carbapenem resistance in Enterobacteriaceae with more prevalence recorded in Klebsiella pneumoniae 24% [0.24 (0.05, 0.44)] followed by 9% [0.09 (−0.03, 0.20)] in Escherichia coli. During the last two decades we observed a striking increase in carbapenem resistance PPr i.e., from 0% [0.00 (−0.02, 0.03)] to 36% [0.36 (0.17, 0.56)]. blaNDM with PPr 15% [0.15 (0.06, 0.23)] in naive isolates was found to be the fundamental genetic determinant for carbapenem resistance in Enterobacteriaceae in Pakistan. Polymyxin B, colistin, tigecycline, and fosfomycin were identified as the suggested treatment options available for multidrug resistant infections not responding to carbapenems. Various studies reported carbapenem resistance from human, animal, and environment sources. ConclusionIn conclusion, we found that NDM-1 producing carbapenem resistant Enterobacteriaceae are increasing in Pakistan. Meta-analysis showed that metallo-β-lactamases producing E. coli ST405 and K. pneumoniae sequence type11 are the major resistant clones. Number of reported studies in various subgroups and inconsistency in following CLSI guidelines are the potential limitations of this meta-analysis. A National antimicrobial resistance (AMR) surveillance strategy based on One Health is urgently needed to check any future AMR crisis in Pakistan.

Matrine reverses the resistance of Haemophilus parasuis to cefaclor by inhibiting the mutations in penicillin-binding protein genes (ftsI and mrcA).

Matrine (MT) is a potential resistance reversal agent. However, it remains unclear whether MT can reverse the resistance of Haemophilus parasuis (H. parasuis) to β-lactams, and, if so, by what mechanism MT works. We screened one cefaclor (CEC)-resistant strain (clinical strain C7) from eight clinical (H. parasuis) strains and determined the underlying resistance mechanism. Then, we investigated the reversal effect of MTon the resistance of this strain to CEC. The production of β-lactamase, overexpression of AcrAB-TolC system, and formation of biofilm might not be responsible for the resistance of clinical strain C7 to CEC. Fourteen mutation sites were found in four PBP genes (ftsI, pbp1B, mrcA, and prcS) of clinical strain C7, among which the mutation sites located in ftsI (Y103D and L517R) and mrcA (A639V) genes triggered the resistance to CEC. The minimum inhibitory concentration (MIC) of CEC against clinical strain C7 was reduced by two to eight folds after MT treatment, accompanied by the significant down-regulated expression of mutated ftsI and mrcA genes. Based on such results, we believed that MT could reverse the resistance of H. parasuis to CEC by inhibiting the mutations in ftsI and mrcA genes. Our research would provide useful information for restoring the antimicrobial activity of β-lactams and improving the therapeutic efficacy of Glässer's disease.

Antimicrobial Resistance and Virulence Potential of Bacterial Species from Captive Birds of Prey-Consequences of Falconry for Public Health.

Falconry has been practiced for thousands of years and is nowadays frequently employed in activities such as pest control, hunting, falcon racing, and environmental education. Antimicrobial resistance levels have risen in the past years, constituting an emerging global problem with a direct impact on public health. Besides both topics being studied on their own, information on the role of captive birds of prey in the potential dissemination of virulence factors and antimicrobial resistance determinants of bacterial origin is scarce. Multidrug-resistant bacteria, including some extended-spectrum β-lactamase producers, have already been found in several captive birds of prey. Most of the virulence factors found in captive raptors' bacteria were related to adherence and invasion abilities, toxin production, and flagella. These birds may acquire these bacteria through contaminated raw food and the exchange of animals between keepers and zoological facilities. More studies are required to confirm the role of captive birds of prey in disseminating resistant bacteria and on the routes of interaction between synanthropic species and humans.

The causes of bacterial bloodstream infections and antimicrobial resistance patterns in children attending a secondary care hospital in Bhaktapur, Nepal, 2017-2022: a retrospective study.

Data on antimicrobial resistance (AMR) among children in Nepal are limited. Here we have characterized the causes of bacterial bloodstream infections (BSIs), antimicrobial resistance patterns and the mechanisms of β-lactamase production in Enterobacterales among children attending outpatient and inpatient departments of a secondary care paediatric hospital in Nepal. We retrospectively collected demographic and clinical data of culture-proven bacterial BSIs between January 2017 and December 2022 among children <18 years attending a 50-bedded paediatric hospital. Stored isolates were subcultured for antimicrobial susceptibility testing against commonly used antimicrobials. Enterobacterales displaying non-susceptibility to β-lactams were phenotypically and genotypically investigated for ESBLs, plasmid-mediated AmpC (pAmpC) β-lactamases and carbapenemases. A total of 377 significant bacteria were isolated from 27 366 blood cultures. Among 91 neonates with a BSI, Klebsiella pneumoniae (n = 39, 42.4%), Pseudomonas aeruginosa (n = 15, 16.3%) and Acinetobacter baumannii complex (n = 13, 14.1%) were most common. In the non-neonates, 275/285 (96.5%) infections were community-acquired including Staphylococcus aureus (n = 89, 32.4%), Salmonella Typhi (n = 54, 19.6%) and Streptococcus pneumoniae (n = 32, 11.6%). Among the 98 S. aureus, 29 (29.6%) were methicillin-resistant Staphylococcus aureus. K. pneumoniae and Escherichia coli demonstrated non-susceptibility to extended-spectrum cephalosporins and carbapenems in both community and hospital-acquired cases. For E. coli and K. pneumoniae, blaCTX-M (45/46), blaEBC (7/10) and blaOXA-48 (5/6) were common among their respective groups. We determined significant levels of AMR among children attending a secondary care paediatric hospital with BSI in Nepal. Nationwide surveillance and implementation of antimicrobial stewardship policies are needed to combat the challenge imposed by AMR.

Mechanisms of Antibiotic Resistance and Developments in Therapeutic Strategies to Combat Klebsiella pneumoniae Infection.

Infections with drug-resistant bacteria have become one of the greatest public health challenges, and K. pneumoniae is among the top six drug-resistant bacteria. K. pneumoniae often causes nosocomial infections, leading to illnesses such as pneumonia, liver abscesses, soft tissue infections, urinary tract infections, bacteremia, and in some cases death. As the pathogen continues to evolve and its multidrug resistance increases, K. pneumoniae poses a direct threat to humans. Drug resistance in K. pneumoniae may occur due to the formation of biofilms, efflux pumps, and the production of β-lactamases. In many cases, resistance is further enhanced by enzymatic modification and loss of porins. Drug resistance to K. pneumoniae has led to a decline in the effectiveness of conventional therapies against this pathogen. Therefore, there is an urgent need to accelerate the development of new antibiotics and explore new therapeutic approaches such as antimicrobial peptides, phages, traditional Chinese medicine, immunotherapy, Antimicrobial nanoparticle technology, antisense oligonucleotides and gene editing technologies. In this review, we discuss the mechanisms of drug resistance in K. pneumoniae and compare several new potential therapeutic strategies to overcome drug resistance in the treatment of K. pneumoniae infections.

Detection of mecA Genes in Hospital-Acquired MRSA and SOSA Strains Associated with Biofilm Formation.

Methicillin-resistant (MR) Staphylococcus aureus (SA) and others, except for Staphylococcus aureus (SOSA), are common in healthcare-associated infections. SOSA encompass largely coagulase-negative staphylococci, including coagulase-positive staphylococcal species. Biofilm formation is encoded by the icaADBC operon and is involved in virulence. mecA encodes an additional penicillin-binding protein (PBP), PBP2a, that avoids the arrival of β-lactams at the target, found in the staphylococcal cassette chromosome mec (SCCmec). This work aims to detect mecA, the bap gene, the icaADBC operon, and types of SCCmec associated to biofilm in MRSA and SOSA strains. A total of 46% (37/80) of the strains were S. aureus, 44% (35/80) S. epidermidis, 5% (4/80) S. haemolyticus, 2.5% (2/80) S. hominis, 1.25% (1/80) S. intermedius, and 1.25% (1/80) S. saprophyticus. A total of 85% were MR, of which 95.5% showed mecA and 86.7% β-lactamase producers; thus, Staphylococcus may have more than one resistance mechanism. Healthcare-associated infection strains codified type I-III genes of SCCmec; types IV and V were associated to community-acquired strains (CA). Type II prevailed in MRSA mecA strains and type II and III in MRSOSA (methicillin-resistant staphylococci other than Staphylococcus aureus). The operon icaADBC was found in 24% of SA and 14% of SOSA; probably the arrangement of the operon, fork formation, and mutations influenced the variation. Methicillin resistance was mainly mediated by the mecA gene; however, there may be other mechanisms that also participate, since biofilm production is related to genes of the icaADBC operon and methicillin resistance was not associated with biofilm production. Therefore, it is necessary to strengthen surveillance to prevent the spread of these outbreaks both in the nosocomial environment and in the community.

Decline in ESBL Production and Carbapenem Resistance in Urinary Tract Infections among Key Bacterial Species during the COVID-19 Pandemic.

The COVID-19 pandemic has led to significant changes in healthcare practices, including increased antibiotic usage. This study aimed to investigate the impact of the pandemic on the prevalence of extended-spectrum β-lactamase (ESBL) production and carbapenem resistance among key bacterial species causing urinary tract infections (UTIs). Conducted at King Fahad Medical City in Riyadh from January 2018 to December 2022, the study analyzed urine samples from 9697 UTI patients. Patients were categorized into 'pre-COVID-19' and 'during COVID-19' groups. Bacterial isolates were identified, and antimicrobial susceptibility testing was performed following guidelines. ESBL production was detected using the Double-Disc Synergy Test. Escherichia coli and Klebsiella pneumoniae were the main pathogens. During the pandemic, ESBL production decreased in E. coli by 1.9% and in K. pneumoniae by 6.0%. Carbapenem resistance also declined, with E. coli displaying a 1.2% reduction and K. pneumoniae and Pseudomonas aeruginosa displaying 10.7% and 7.9% reductions, respectively. Notably, logistic regression analysis revealed that the odds of ESBL presence were 10% lower during the COVID-19 pandemic (OR 0.91; 95% CI 0.83-0.99; p = 0.040), and there was a significant reduction in the odds of carbapenem resistance (OR 0.43; 95% CI 0.37-0.51; p < 0.001). This study reveals a significant decrease in ESBL production and carbapenem resistance among UTI pathogens during the COVID-19 pandemic, hinting at the impact of modified antibiotic and healthcare approaches. It emphasizes the need for persistent antimicrobial resistance surveillance and policy adaptation to address resistance challenges, offering key directions for future public health actions.

Correlation between antimicrobial resistance, biofilm formation, and virulence determinants in uropathogenic Escherichia coli from Egyptian hospital

BackgroundUropathogenic Escherichia coli (UPEC) is the main etiological agent behind community-acquired and hospital-acquired urinary tract infections (UTIs), which are among the most prevalent human infections. The management of UPEC infections is becoming increasingly difficult owing to multi-drug resistance, biofilm formation, and the possession of an extensive virulence arsenal. This study aims to characterize UPEC isolates in Tanta, Egypt, with regard to their antimicrobial resistance, phylogenetic profile, biofilm formation, and virulence, as well as the potential associations among these factors.MethodsOne hundred UPEC isolates were obtained from UTI patients in Tanta, Egypt. Antimicrobial susceptibility was assessed using the Kirby-Bauer method. Extended-spectrum β-lactamases (ESBLs) production was screened using the double disk synergy test and confirmed with PCR. Biofilm formation was evaluated using the microtiter-plate assay and microscopy-based techniques. The phylogenetic groups of the isolates were determined. The hemolytic activity, motility, siderophore production, and serum resistance of the isolates were also evaluated. The clonal relatedness of the isolates was assessed using ERIC-PCR.ResultsIsolates displayed elevated resistance to cephalosporins (90–43%), sulfamethoxazole-trimethoprim (63%), and ciprofloxacin (53%). Ninety percent of the isolates were multidrug-resistant (MDR)/ extensively drug-resistant (XDR) and 67% produced ESBLs. Notably, there was an inverse correlation between biofilm formation and antimicrobial resistance, and 31%, 29%, 32%, and 8% of the isolates were strong, moderate, weak, and non-biofilm producers, respectively. Beta-hemolysis, motility, siderophore production, and serum resistance were detected in 64%, 84%, 65%, and 11% of the isolates, respectively. Siderophore production was correlated to resistance to multiple antibiotics, while hemolysis was more prevalent in susceptible isolates and associated with stronger biofilms. Phylogroups B2 and D predominated, with lower resistance and stronger biofilms in group B2. ERIC-PCR revealed considerable diversity among the isolates.ConclusionThis research highlights the dissemination of resistance in UPEC in Tanta, Egypt. The evident correlation between biofilm and resistance suggests a resistance cost on bacterial cells; and that isolates with lower resistance may rely on biofilms to enhance their survival. This emphasizes the importance of considering biofilm formation ability during the treatment of UPEC infections to avoid therapeutic failure and/or infection recurrence.

Polluted surface water is a repository of antibiotic-resistant Escherichia coli harbouring Plasmid-Mediated Quinolone Resistance (PMQR) determinants

ABSTRACT We investigated the carriage of PMQR determinants by E. coli from surface water and their antibiotypes. Water samples were collected and analysed from two surface water: Agbowo (AG) and Arulogun (AR) in South-west Nigeria for E. coli, which were identified using PCR detection of uidA. Susceptibility to antibiotics was done using the disc-diffusion method. Detection of PMQR genes in isolates showing complete resistance or intermediate susceptibility to the fluoroquinolone antibiotics was done using primer-specific PCR. Thirty-six E. coli isolates were obtained [AG (20) and AR (16)]. The isolates showed different levels of resistance to the tested antibiotics, with 100% resistance to amoxicillin-clavulanate. None of the isolates was positive for extended spectrum β-lactamase (ESBL) production, but 25 showed complete resistance or intermediate susceptibility to the fluoroquinolone antibiotics. Two isolates each from AG and AR carried qnrA, one isolate carried qnrS, with one each from AG and AR carrying aac(6′)-lb-cr. Four isolates carried oqxAB, but, qnrB and qepA were not detected in any isolate. This study revealed that polluted surface water is a ‘hub’ of antibiotic-resistant E. coli harbouring PMQR genes.

Phenotypic and Molecular Characterization of a Hospital Outbreak Clonal Lineage of Salmonella enterica Subspecies enterica serovar Mikawasima Containing blaTEM-1B and blaSHV-2 That Emerged on a Neonatal Ward, During the COVID-19 Pandemic.

Nontyphoid salmonella can cause severe infections in newborns and is therefore declared a pathogen of major health significance at this age. The aim of the study was molecular and antimicrobial characterization of β-lactamase-producing Salmonella Mikawasima outbreak clone on a Neonatal ward, University Hospital of Split (UHS), Croatia during the COVID-19 pandemic. From April 2020, until April 2023, 75 nonrepetitive strains of Salmonella Mikawasima were isolated from stool specimens and tested for antimicrobial resistance. All 75 isolates were resistant to ampicillin and gentamicin, while 98% of isolates were resistant to amoxicillin/clavulanic acid. A high level of resistance was observed to third-generation cephalosporins (36% to ceftriaxone and 47% to ceftazidime). Extended-spectrum β-lactamase production was phenotypically detected by double-disk synergy test in 40% of isolates. Moderate resistance to quinolones was detected; 7% of isolates were resistant to pefloxacin and ciprofloxacin. All isolates were susceptible to carbapenems, chloramphenicol, and co-trimoxazole. Fourteen representative isolates, from 2020, 2021, 2022, and 2023, were analyzed with PFGE and all of them belong to the same clone. Whole-genome sequencing (WGS) analysis of three outbreak-related strains (SM1 and SM2 from 2020 and SM3 from 2023) confirmed that these strains share the same serotype (Mikawasima), multilocus sequence typing profile (ST2030), resistance genes [blaTEM-1B, aac(6')-Iaa, aac(6')-Im, and aph(2'')-Ib)] and carry incompatibility group C (IncC) plasmid. Furthermore, the gene blaSHV-2 was detected in SM1 and SM2. In summary, WGS analysis of three representative strains clearly demonstrates the persistence of β-lactamase-producing Salmonella Mikawasima in UHS during the 4-year period.

Phenotypic Detection of Extended Spectrum β-lactamase Producing Gram Negative Bacteria Isolated From Clinical Specimens

Background: Over the past decade, there has been a significant global rise in extended spectrum β-lactamase (ESBL) producing gram negative bacteria (GNB), posing a substantial concern. ESBLs, encoded by plasmids, are deemed threatening due to their ease of transmission between species. The Asia Pacific region has witnessed a surge in hospital-acquired infections attributed to ESBL-producing GNB, as highlighted by numerous studies. This study seeks to assess the prevalence of ESBL-producing GNB specifically within Nepal. Methods: This research, conducted at Grande International Hospital in Kathmandu, Nepal, adopted a descriptive cross-sectional approach. It spanned from July 2016 to February 2017 and encompassed patients receiving care at the hospital. The study involved the handling of samples directed to the Microbiology laboratory for Culture and sensitivity, as well as the identification of isolates and Antibiotic susceptibility testing, following established microbiological protocols. Screening for Multi-Drug resistance (MDR) and Extended Spectrum Beta-Lactamase (ESBL) was conducted for all Escherichia coli and Klebsiella pneumoniae isolates utilizing a combined Disk (CD) test method. Results: Out of 258 Escherichia coli and Klebsiella pneumoniae isolates, 42 isolates of E. coli and 21 isolates of K. pneumoniae were confirmed as ESBL producer. Conclusion: The regular surveillance of hospital-associated infections including monitoring of antimicrobial susceptibility pattern is needed for the formulation of a definite antimicrobial policy.

Methicillin, β-lactams, and Clindamycin Resistance Profiles of Staphylococcus aureus Strains Isolated from Patients with UTI in Bechar Province (Algeria)

Introduction: Staphylococcus aureus is a bacterial pathogen responsible for many dis-eases. Multidrug resistance in S aureus has become common worldwide and is a serious clinical issue in the treatment and care of S. aureus-infected patients. S. aureus uropathogenic strains isolated from patients with UTI in Bechar province (Algeria) were phenotypically identified and evaluated for multiple drug resistance (MDR) patterns against recommended antimicrobial drugs. Methods: Through selective media, the uropathogenic S. aureus strains were isolated by analyzing a total of 211 urine samples, then subjected to various biochemical identification tests. Multidrug resistance pattern (MRSA, MLSB, and β-lactamase production) among Staphylococcus aureus uropathogenic strains was performed using phenotypic tests. : A total of 50 S. aureus strains were isolated, i.e., 40,48% of all the isolated uropathogenic agents estimated at 126 isolates. More than 69% of the women had a urinary tract infection, i.e., a sex ratio (SR) of 0,43. The susceptibility test results showed that the isolated S. aureus strains were resistant to various antibiotics of the β-lactams class (penicillin, cefoxitin, and oxacillin) and were susceptible to gentamicin, chloramphenicol, co-trimoxazole, vancomycin, ofloxacin, and ciprofloxacin. Cefoxitin disk diffusion and agar screening tests showed that all the isolated S. aureus strains were qualified as MRSA at the rate of 100% (50/50), whereas a rate of 74% (37/50) was granted to MRSA using oxacillin disk diffusion test. The highest percentage of MDR-MRSA was observed in class three of antibiotics 12 (24%). The lowest percentage was observed in classes 8 and 9 of antibiotics 1 (2%). For MDR-MRSA, the MAR index ranged from 0,27 to 1,0. Results:: Penicillin disk diffusion (DD) and DDST (PI/PIT) tests showed a production rate of β-lactamase in the range of 94% and 80%, respectively. 85,1% (40/50) of penicillin-resistant strains were positive for DDST. Thus, the D-test among MRSA strains shows a rate of 38% (19/50) of cMLSB and no strain attributed to the iMLSB phenotype. Conclusion: This is an alarming rate, confirming the concern that is still being discussed within the medical teams of the national health sector as well as the Algerian antimicrobial resistance network, which requires prompt intervention to update a new strategy to fight antimicrobial re-sistance.

Characteristics of non-carbapenemase producing carbapenem-resistant Klebsiella pneumoniae from a tertiary hospital in China.

The spread of carbapenem-resistant Klebsiella pneumoniae (CRKP) is a substantial severe global public health burden. Non-carbapenemase-producing CRKP (non-CP-CRKP) is increasingly recognized as the source of severe infections. We analyzed the genotypic, and phenotypic profiles of non-CP-CRKP strains with the whole-genome sequences isolated between 2017 and 2019 and the clinical characterization of non-CP-CRKP infection. A total of 91 CRKP strains were collected, of which 5 (5.49%) strains were non-CP-CRKP. Four strains were from male patients; three strains were isolated from the bile of patients who underwent biliary interventional surgery and four had a history of antibiotic exposure. Three strains were sequence type (ST)11, one was ST1, and one was ST5523. The non-CP-CRKP strains were insusceptible to ertapenem. Three strains were susceptible to amikacin. All the strains were susceptible to imipenem, meropenem, tigecycline, ceftazidime/avibatam and polymyxin B. The β-lactamases of non-CP-CRKP predominantly included blaCTX-M, blaSHV, and blaTEM subtypes. Two site mutations in ompK36 (p.A217S and p.N218H) and four in ompK37 (p.I70M, p.I128M, p.N230G, and m233_None234insQ) were detected accounting for carbapenem resistance. Plasmids IncFI and IncFII were found in most strains. Genes encoding aerobactin, yersiniabactin and allantoin utilization were not detected in several isolates, and all non-CP-CRKP strains did not carry rmpA gene. Non-CP-CRKP infected patients had a history of previous antibiotic exposure or invasive procedures. Non-CP-CRKP strains were insusceptible to ertapenem. The mechanism of resistance includes β-lactamases production and the site mutations in ompK36 and ompK37. Several virulence genes were not detected in non-CP-CRKP.

Genomic analysis of Salmonella enterica from Metropolitan Manila abattoirs and markets reveals insights into circulating virulence and antimicrobial resistance genotypes.

The integration of next-generation sequencing into the identification and characterization of resistant and virulent strains as well as the routine surveillance of foodborne pathogens such as Salmonella enterica have not yet been accomplished in the Philippines. This study investigated the antimicrobial profiles, virulence, and susceptibility of the 105 S. enterica isolates from swine and chicken samples obtained from slaughterhouses and public wet markets in Metropolitan Manila using whole-genome sequence analysis. Four predominant serovars were identified in genotypic serotyping, namely, Infantis (26.7%), Anatum (19.1%), Rissen (18.1%), and London (13.3%). Phenotypic antimicrobial resistance (AMR) profiling revealed that 65% of the isolates were resistant to at least one antibiotic, 37% were multidrug resistant (MDR), and 57% were extended-spectrum β-lactamase producers. Bioinformatic analysis revealed that isolates had resistance genes and plasmids belonging to the Col and Inc plasmid families that confer resistance against tetracycline (64%), sulfonamide (56%), and streptomycin (56%). Further analyses revealed the presence of 155 virulence genes, 42 of which were serovar-specific. The virulence genes primarily code for host immune system modulators, iron acquisition enzyme complexes, host cell invasion proteins, as well as proteins that allow intracellular and intramacrophage survival. This study showed that virulent MDR S. enterica and several phenotypic and genotypic AMR patterns were present in the food chain. It serves as a foundation to understand the current AMR status in the Philippines food chain and to prompt the creation of preventative measures and efficient treatments against foodborne pathogens.

Emerging antibiotic resistance in Plesiomonasshigelloides: insights from surface waters in Southwest Nigeria

Abstract This study aimed to investigate the antibiotic resistance pattern, extended-spectrum β-lactamase (ESBL) production, and biofilm formation potential of Plesiomonas shigelloides in selected surface waters in southwestern Nigeria. Isolates were identified using the spread plate technique on inositol brilliant green bile agar and confirmed molecularly by polymerase chain reaction. Antibiotic susceptibility was determined using the Kirby–Bauer disc diffusion method, ESBL production by the double disc synergistic test, and biofilm formation by the test tube method. A total of 111 P. shigelloides isolates were identified and confirmed. Significant resistance rates were observed against cefuroxime (71%), cefotaxime (92%), and ceftazidime (92%), while high susceptibility was noted for ciprofloxacin (94%), gentamicin (96%), and chloramphenicol (100%). A higher prevalence of multiple drug resistant phenotypes was observed during the dry season, reaching 79% and 60% along sampled rivers. Biofilm-producing phenotypes exhibited robust homogeneous biofilm formation. In this study, P. shigelloides exhibited high resistance to critical antibiotics such as third-generation cephalosporins. However, isolates displayed susceptibility to ciprofloxacin, gentamicin, and chloramphenicol. The presence of ESBL phenotypes and strong biofilm formation emphasizes the potential threat of P. shigelloides as an emerging environmental pathogen, highlighting the importance of monitoring and understanding antibiotic resistance patterns for effective public health management strategies.

Bloodstream Infections in Pediatric Oncology Patients: Bacterial Pathogen Distribution and Antimicrobial Susceptibility at the University Hospital Centre Zagreb, Croatia-A 5-Year Analysis.

The epidemiology of bacterial pathogens causing bloodstream infections (BSIs) in pediatric hematology/oncology patients is changing and resistance to antimicrobial agents is globally spread. We retrospectively assessed demographic, clinical, and microbiologic data of BSIs during a 5-year period at a pediatric hematology/oncology unit from January 1, 2017, to December 31, 2021, at the University Hospital Centre Zagreb, Zagreb, Croatia. In 66 pediatric patients with malignancies, 93 BSI episodes were registered and 97 bacterial isolates were cultured. The Gram-positive versus Gram-negative ratio was 67 (69.1%) versus 30 (30.9%). Coagulase-negative staphylococci (48; 49.6%) were the most frequent isolates, followed by Enterobacterales (17; 17.5%) and Staphylococcus aureus (6; 6.2%). Multidrug resistance isolates included extended spectrum β-lactamase producers (n=3). Resistance rates to piperacillin/tazobactam, cefepime, and meropenem in Gram-negative isolates were 15.4%, 14.3%, and 0.0%, respectively. Gram-positive bacteria are the most common cause of BSI in our patients. Resistance rates to piperacillin/tazobactam and cefepime in Gram-negative isolates make meropenem a better choice for empirical antimicrobial treatment. As national and hospital data may differ, the surveillance of pathogen distribution and antimicrobial susceptibility in pediatric hematology/oncology wards is necessary to adjust empirical treatment accordingly.