Search Results (24)

Objective: This systematic review and meta-analysis aims to evaluate the temporal changes in Helicobacter pylori antibiotic resistance in Russia based on studies published over the past 15 years. Materials and Methods: We conducted a comprehensive literature search in MEDLINE/PubMed, EMBASE, the Russian Science Citation Index, and Google Scholar, following the PRISMA 2020 guidelines. Our meta-analysis was pre-registered in PROSPERO (CRD 420251025636). The inclusion criteria included original research, published in English or Russian in 2011–2024, involving antibiotic susceptibility testing in treatment-naive Russian adults using validated diagnostic methods. Two independent researchers selected studies and extracted data using standardized procedures, with methodological quality assessed via the Newcastle–Ottawa Scale. Pooled resistance rates were calculated using fixed/random-effects models in MedCalc 23.1.5 and Python 3.9.21, with meta-regression investigating temporal trends and subgroup analyses examining regional and methodological variations. Results: We identified 16 studies comprising 1206 H. pylori isolates. The pooled analysis of studies (2011–2025) revealed an overall clarithromycin resistance rate of 15.236%, with a significant temporal increase from 11.903% pre-2015 to 21.024% in 2020–2024 (p = 0.0049). Metronidazole showed consistently high pooled resistance (33.309%), while amoxicillin (1.828%), levofloxacin (19.014%), tetracycline (1.328%), and rifampicin (5.803%) maintained low resistance rates, and dual clarithromycin–metronidazole resistance was observed in 2.793% of isolates. Regional disparities were notable in the two largest cities of Russia, with 18.763% clarithromycin resistance in Moscow versus 28.540% in Saint-Petersburg. Conclusions: Russia surpasses the Maastricht VI Consensus resistance threshold for clarithromycin (15%), necessitating revision of empirical treatment strategies. The significant increase in clarithromycin resistance, potentially exacerbated by antibiotic use during the COVID-19 pandemic, underscores the urgent need for resistance-guided therapies and ongoing national surveillance programs to optimize H. pylori management. Full article

Background/Objectives: Typhoid fever caused by Salmonella enterica serovar Typhi remains an important public health problem in Ghana. Understanding the epidemiology and antimicrobial resistance patterns of S. Typhi is crucial to guide the treatment and control of typhoid fever. This systematic review and meta-analysis aimed to estimate the prevalence of typhoid fever in Ghana and describe the antibiotic susceptibility profiles. Methods: Literature searches were conducted using the PubMed repository and three databases: Scopus, Web of Science, and ScienceDirect. Observational studies reporting typhoid fever prevalence among Ghanaian participants diagnosed by culture or Widal test and published between 1 January 2004 and 16 August 2024 were eligible. Quality was assessed using standardized JBI critical appraisal checklists. Random-effects meta-analysis with a 95% confidence interval was performed to estimate pooled prevalence and conduct subgroup analyses. Results: A total of 22 studies involving 228,107 participants were included in the systematic review. The pooled prevalence of typhoid fever was 4.14% (95% CI: 2.78–5.75). Blood culture detected more cases (3.68%) than stool culture (1.16%). Multidrug resistance was documented in 20–66% of isolates, and ciprofloxacin had the lowest prevalence of resistance (0–17%). Conclusions: This review highlights the substantial typhoid fever burden and evolving antimicrobial resistance in Ghana. Continuous surveillance of the disease is warranted to optimize empiric treatment and control strategies, given the resistance to first-line drugs. Enhanced prevention through water, sanitation, and vaccination programs is imperative. Full article

Antimicrobial resistance is increasingly becoming a serious public health issue. There is scientific evidence linking the use of antibiotics in livestock production to the emergence and spread of resistance in bacteria that are important for human health. To assess the prevalence of antimicrobial resistance in Escherichia coli and Enterococcus spp., fecal and slurry wastewater samples were collected from various cattle and swine farms, mainly located in the northern and central regions of Portugal. Samples from each farm were pooled for microbiological processing to isolate Escherichia coli and Enterococcus spp., followed by specific antibiotic susceptibility testing for each species using the disk diffusion method. The results of these analyses indicated a significant issue with tetracycline resistance in E. coli and Enterococcus spp. Furthermore, a notably higher frequency in resistant strains was observed in the majority of slurry samples compared to those derived from swine feces. This observation led to the hypothesis that slurry may provide a comprehensive historical perspective for studying the antibiotic resistance patterns present on a farm. Full article

Background: The nasopharyngeal carriage of Streptococcus pneumoniae can be the source of transmission between humans and the starting step towards invasive pneumococcal diseases. Data on the carriage of pneumococci in children before and after the pneumococcal conjugate vaccines (PCV) integration in a country are essential for monitoring any change in pneumococcal carriage serotypes and their antimicrobial-resistance profiles. Methods: We investigated the epidemiology of S. pneumoniae carriage among children younger than five years old in Tripoli, Lebanon, in 2016, the same year of integration of PCV13 in the country’s Expanded Program on Immunization. Results: Of 104 participating children, 57 (54.8%) gave a positive culture for S. pneumoniae. Antimicrobial susceptibility testing revealed that 26.3% of isolates were multidrug-resistant. Resistance was detected mainly against oxacillin (77.2%), tetracycline (29.8%), erythromycin (22.8%), trimethoprim-sulfamethoxazole (22.8%), clindamycin (19.3%), minocycline (19.3%), and teicoplanin (1.8%). Serotyping analysis identified 14 distinct serotypes, with only 31.3% and 50% of isolates corresponding to vaccine serotypes covered by PCV13 and PCV20, respectively. The most common serotypes were 11A, 19F, 23A, and those of serogroup 24 (Sg24) accounted for 37.5% of the serotyped isolates. Conclusions: Our findings have revealed the circulation of a pool of pneumococci isolates with high levels of antibiotic resistance and different degrees of likelihood of causing invasive diseases in children under five years old in Tripoli in 2016. The overall limited PCV13 vaccine coverage in this study highlighted the need for vaccines with greater coverage in the immunization programs in Lebanon. Longitudinal national studies investigating the carriage of pneumococci in children are required to further assess the impact of the PCV vaccine on pneumococci carriage in children and steer new vaccine development. Full article

Background/Objectives: Urinary tract infections (UTIs) pose an increasing risk of antimicrobial resistance, and novel diagnostic tests have been developed to address the limitations of standard urine culture in these cases. It is important that these novel tests be validated for agreement and error rates against the standard antibiotic susceptibility testing (AST) methods. Methods: Polymicrobial (≥two non-fastidious microorganisms) consecutive clinical urine specimens submitted for UTI diagnostic testing were included in this analysis. Specimens were tested with Pooled Antibiotic Susceptibility Testing (P-AST) and with broth microdilution/disk diffusion (BMD/DD) in parallel. Performance characteristics, such as essential agreement (EA%), very major errors (VMEs), and major errors (MEs), were assessed using Clinical and Laboratory Standards Institute (CLSI) standards. Specimens with P-AST-resistant and BMD/DD consensus-sensitive results were assessed for heteroresistance. Real-world clinical sample data were used to assess associations between increasing organism counts and average “sensitive” antibiotic count per sample. Results: The essential agreement between P-AST and standard isolate AST was ≥90%, VMEs were <2.0%, and MEs were <3.0%, meeting the CLSI guidelines for AST verification and validation studies. When heteroresistance was accounted for, overall VMEs and MEs were both <1.5%. The presence of additional non-fastidious organisms dropped the number of average “sensitive” antibiotics from 9.8 with one organism to 2.5 with five or more organisms. The presence of fastidious organisms did not have any meaningful impact. Conclusions: P-AST, a component of the Guidance^® UTI assay (Pathnostics, Irvine, CA, USA), performed within CLSI standards for AST in polymicrobial UTI diagnostic urine specimens. Full article

Background/Objectives: While new methods for measuring antimicrobial susceptibility have been associated with improved patient outcomes, they should also be validated using standard protocols for error rates and other test metrics. The objective of this study was to validate a novel susceptibility assay for complicated and recurrent urinary tract infections (UTIs): pooled antibiotic susceptibility testing (P-AST). This assay was compared to broth microdilution (BMD) and disk diffusion (DD), following Clinical and Laboratory Standards Institute (CLSI) guidelines for assessment of error rates and agreement. Methods: This study analyzed consecutive fresh clinical urine specimens submitted for UTI diagnostic testing. Upon receipt, the urine samples were subjected in parallel to standard urine culture and multiplex polymerase chain reaction (M-PCR) for microbial identification and quantification. Specimens with the same monomicrobial non-fastidious bacteria detected by both M-PCR and standard urine culture (SUC) underwent standard antibiotic susceptibility testing (AST) and P-AST antibiotic susceptibility testing. Analysis was also undertaken to assess the presence of heteroresistance for specimens with P-AST-resistant and BMD/DD consensus-susceptible results. Results: The performance measures without correction for heteroresistance showed essential agreement (EA%) of ≥90%, very major errors (VMEs) of <1.5%, and major errors (MEs) of <3.0% for P-AST, all meeting the threshold guidelines established by CLSI for AST. The categorical agreement (CA%) also met acceptable criteria (>88%), as the majority of the errors were minor (mEs) with essential agreement. The very major and major error rates for P-AST decreased to <1.0% when heteroresistance was accounted for. Conclusions: The P-AST assay methodology is validated within acceptable parameters when compared to broth microdilution and disk diffusion using CLSI criteria. Full article

Background/Objectives: Animals destined for human consumption play a key role in potentially transmitting bacteria carrying antibiotic resistance genes. However, there is limited knowledge about the carriage of antibiotic-resistant bacteria in native breeds. We aimed to characterize the phenotypic profiles and antibiotic resistance genes in Escherichia coli isolated from bovines, including three native Portuguese bovine breeds. Methods: Forty-nine E. coli isolates were selected from 640 fecal samples pooled by age group (eight adult or eight calf samples) from each farm, representing both dairy cattle raised in intensive systems and meat cattle raised in extensive systems in Northern Portugal. The presumptive E. coli colonies plated onto MacConkey agar were confirmed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The antibiotic resistance profiles were screened by antimicrobial susceptibility testing (EUCAST/CLSI guidelines), and the antibiotic resistance genes by PCR. Results: Most isolates showed resistance to ampicillin (69%), tetracycline (57%), gentamicin (55%), and trimethoprim + sulfamethoxazole (53%), with no resistance to imipenem. Resistance to at least one antibiotic was found in 92% of isolates, while 59% exhibited multidrug resistance. Most calf isolates, including those from native breeds, showed a multidrug-resistant phenotype. Among the adults, this was only observed in Holstein-Friesian and Barrosã cattle. None of the Holstein-Friesian isolates were susceptible to all the tested antibiotics. ESBL-producing E. coli was identified in 39% of isolates, including those from Holstein-Friesian calves and adults, Cachena calves and Minhota adults. The sul2 gene was detected in 69% of isolates, followed by bla_CTX-M (45%), aac(3′)-IV (41%), and aac(6′)-Ib-cr (31%), with a higher prevalence in adults. Conclusions: This pioneering study highlights the concerning presence of multidrug-resistant E. coli in native Portuguese cattle breeds. Full article

Background/Objectives: We aimed to compare the prescribing behavior and clinical experience of urology providers when using the combined multiplex polymerase chain reaction (M-PCR)/Pooled Antibiotic Susceptibility Testing (P-AST) diagnostic test versus the standard urine culture (SUC) in the same set of patients previously reported to have improved clinical outcomes with M-PCR/P-AST. Methods: We conducted a multi-centered, prospective, observational study (clinical trial registration: NCT05091931) with Western Institutional Review Board (IRB) approval (20214705). Adult subjects were split between the M-PCR/P-AST (n = 250) and SUC arms (n = 135). Treatment details were determined by clinician and subject surveys. Differences in prescribed antibiotics were compared using the Chi-square or Fisher’s exact test. Results: There was no significant difference in the overall use of “access” antibiotics (p = 1.0) or first-line drugs (p = 0.4483) between M-PCR/P-AST and SUC. Nitrofurantoin (p = 0.0172) and metronidazole (p = 0.0309) were more frequently used with M-PCR/P-AST, while amoxicillin/clavulanate (p = 0.0008), cefuroxime (p = 0.0378), and ertapenem (p = 0.0378) were more frequently used with SUC. Conclusions: The use of M-PCR/P-AST to guide complicated UTI management was not associated with the increased use of non-first-line antibiotics, such as carbapenems, compared to SUC. Combined with the prior reported evidence of improved patient outcomes in this same set of patients, this test should be considered for utilization when managing complicated UTI cases. Full article

Antimicrobial resistance (AMR) is one of the major global health and economic threats. There is growing concern about the emergence of AMR in food and the possibility of transmission of microorganisms possessing antibiotic resistance genes (ARGs) to the human gut microbiome. Shotgun sequencing and in vitro antimicrobial susceptibility testing were used in this study to provide a detailed characterization of the antibiotic resistance profile of bacteria and their ARGs in dromedary camel milk. Eight pooled camel milk samples, representative of multiple camels distributed in the Kuwait desert, were collected from retail stores and analyzed. The genotypic analysis showed the presence of ARGs that mediate resistance to 18 classes of antibiotics in camel milk, with the highest resistance to fluoroquinolones (12.48%) and disinfecting agents and antiseptics (9%). Furthermore, the results pointed out the possible transmission of the ARGs to other bacteria through mobile genetic elements. The in vitro antimicrobial susceptibility testing indicated that 80% of the isolates were resistant to different classes of antibiotics, with the highest resistance observed against three antibiotic classes: penicillin, tetracyclines, and carbapenems. Multidrug-resistant pathogens including Klebsiella pneumoniae, Escherichia coli, and Enterobacter hormaechei were also revealed. These findings emphasize the human health risks related to the handling and consumption of raw camel milk and highlight the necessity of improving the hygienic practices of farms and retail stores to control the prevalence of ARGs and their transmission. Full article

A two-dimensional “checkerboard” array employing systematic titration (e.g., serial two-fold dilutions) is a well-established in vitro method for exploring the antibacterial effects of novel drug combinations. Minimum inhibitory concentrations (MICs) on the checkerboard are isoeffective points at which the antibiotic potency is the same. Representations of checkerboard MIC curves for a β-lactam and β-lactamase inhibitor combination are used in hypothetical “thought experiments” and reveal the ways in which current practices can be improved. Because different types of response (i.e., independence vs. additivity vs. one effective agent; interaction vs. noninteraction) produce different MIC curves, data from different strains/isolates should not be pooled indiscriminately, as the composition of a pooled dataset will influence any derived pharmacokinetic/pharmacodynamic (PK/PD) index. Because the β-lactamase inhibitor threshold concentration (C_T) parameter is a function of the β-lactam partner dosing regimen, it is not possible to derive a universal PK/PD index target based on C_T. Alternative susceptibility testing methods represent different planes through the checkerboard; a fixed ratio method is less prone to bias for all β-lactam and β-lactamase inhibitor combinations. Susceptibility test MICs will often not reflect the sensitivity of the strain/isolate to the β-lactamase inhibitor, so the use of these MICs to normalize PK/PD indices is inappropriate. Full article

A rising incidence of clinical infections has been caused by Kluyvera, a significant opportunistic pathogen. Meanwhile, Kluyvera acts as an important reservoir of bla_CTX-Ms, which are the dominant genes of class A extended-spectrum β-lactamases (ESBLs). In this work, 60 strains of Kluyvera were subjected to phylogenetic relationship reconstruction, antimicrobial susceptibility testing, and antibiotic resistance genes prediction. All mature bla_CTX-Ms were gathered to perform subgroup reclassification. The findings demonstrate that Kluyvera has a large gene pool with significant genetic flexibility. Notably, 25% of strains showed simultaneous detection of ESBLs and carbapenem resistance genes. The genotypes of fourteen novel bla_CTX-Ms were identified. A new subgroup classification approach for bla_CTX-Ms was defined by using 20 amino acid site variants, which could split bla_CTX-Ms into 10 subgroups. The results of the subgroup division were consistent with the phylogenetic clustering. More significantly, we proposed a novel bla_CTX-M subgroup, KLUS, that is chromosomally encoded in K. sichuanensis and the new species put forward in this study, showing amino acid differences from the currently known sequences. Cloning and transformation tests demonstrated that the recipient bacteria had a robust phenotype of cefotaxime resistance. Closely related Kluyvera species had bla_CTX-Ms in the same subgroup. Our research lays the groundwork for a deeper comprehension of Kluyvera and emphasizes how important a bla_CTX-M reservoir it is. We provide an update on bla_CTX-M subgroups reclassification from the aspects of phylogenetic relationship, amino acid differences, and the new subgroup KLUS, which needs to be strengthen monitored due to its strong resistance phenotype to cefotaxime. Full article

The gastrointestinal tracts of dairy calves and cows are reservoirs of antimicrobial-resistant bacteria (ARB), which are present regardless of previous antimicrobial therapy. Young calves harbor a greater abundance of resistant bacteria than older cows, but the factors driving this high abundance are unknown. Here, we aimed to fully characterize the genomes of multidrug-resistant (MDR) and antimicrobial-susceptible Escherichia coli strains isolated from pre-weaned calves, post-weaned calves, dry cows, and lactating cows and to identify the accessory genes that are associated with the MDR genotype to discover genetic targets that can be exploited to mitigate antimicrobial resistance in dairy farms. Results indicated that both susceptible and resistant E. coli isolates recovered from animals on commercial dairy operations were highly diverse and encoded a large pool of virulence factors. In total, 838 transferrable antimicrobial resistance genes (ARGs) were detected, with genes conferring resistance to aminoglycosides being the most common. Multiple sequence types (STs) associated with mild to severe human gastrointestinal and extraintestinal infections were identified. A Fisher’s Exact Test identified 619 genes (ARGs and non-ARGs) that were significantly enriched in MDR isolates and 147 genes that were significantly enriched in susceptible isolates. Significantly enriched genes in MDR isolates included the iron scavenging aerobactin synthesis and receptor genes (iucABCD-iutA) and the sitABCD system, as well as the P fimbriae pap genes, myo-inositol catabolism (iolABCDEG-iatA), and ascorbate transport genes (ulaABC). The results of this study demonstrate a highly diverse population of E. coli in commercial dairy operations, some of which encode virulence genes responsible for severe human infections and resistance to antibiotics of human health significance. Further, the enriched accessory genes in MDR isolates (aerobactin, sit, P fimbriae, and myo-inositol catabolism and ascorbate transport genes) represent potential targets for reducing colonization of antimicrobial-resistant bacteria in the calf gut. Full article

This study compared rates of empirical-therapy use and negative patient outcomes between complicated and recurrent urinary tract infection (r/cUTI) cases diagnosed with a multiplex polymerase chain reaction or pooled antibiotic susceptibility testing (M-PCR/P-AST) vs. standard urine culture (SUC). Subjects were 577 symptomatic adults (n = 207 males and n = 370 females) presenting to urology/urogynecology clinics between 03/30/2022 and 05/24/2023. Treatment and outcomes were recorded by the clinician and patient surveys. The M-PCR/P-AST (n = 252) and SUC (n = 146) arms were compared after patient matching for confounding factors. The chi-square and Fisher’s exact tests were used to analyze demographics and clinical outcomes between study arms. Reduced empirical-treatment use (28.7% vs. 66.7%), lower composite negative events (34.5% vs. 46.6%, p = 0.018), and fewer individual negative outcomes of UTI-related medical provider visits and UTI-related visits for hospitalization/an urgent care center/an emergency room (p < 0.05) were observed in the M-PCR/P-AST arm compared with the SUC arm. A reduction in UTI symptom recurrence in patients ≥ 60 years old was observed in the M-PCR/P-AST arm (p < 0.05). Study results indicate that use of the M-PCR/P-AST test reduces empirical antibiotic treatment and negative patient outcomes in r/cUTI cases. Full article

Escherichia coli (E. coli), a major foodborne disease-causing pathogen found in raw cow milk, has even far more reaching public health ramifications as it encodes for antimicrobial resistance (AMR). This study aimed to identify multidrug-resistant (MDR) E. coli from raw cow’s milk and evaluate their antimicrobial-resistant profiles. In total, 418 pooled raw cow milk samples were collected from milk collection centers and analysed using standard culture methods to isolate E. coli. Antimicrobial Susceptibility Testing (AST) was conducted using the Kirby Bauer disk diffusion method and PCR was used to identify cefotaxime (CTX) resistant genes. Overall isolation of E. coli was 51.2% (214/418) with MDR observed in 21% (45/214) of isolates across different antibiotic combinations. Resistance was observed towards ampicillin (107/214, 50%), tetracycline (86/214, 40.1%), trimethoprim/sulfamethoxazole (61/214, 28.5%), and amoxicillin/clavulanic acid (CTX) (50/214, 23.4%). Notably, 15% (32/214) resistance to CTX was observed, while 12.6% (27/214) exhibited resistance to imipenem. The bla_CTX-M and bla_TEM genes were detected in CTX-resistant isolates. The findings of MDR E. coli that harbour bla_CTX-M and bla_TEM genes in raw cow’s milk indicate serious public health risks for consumers. Full article

Background: Antibiotic eye drops are frequently used in clinical practice. Due to the anatomical connection via the nasolacrimal duct, it seems possible that they have an influence on the nasal/pharyngeal microbiome. This was investigated by using two different commonly used antibiotic eye drops. Methods: 20 subjects were randomized to four groups of five subjects receiving eye drops containing gentamicin, ciprofloxacin, or, as controls, unpreserved povidone or benzalkonium chloride-preserved povidone. Nasal and pharyngeal swabs were performed before and after the instillation period. Swabs were analyzed by Illumina next-generation sequencing (NGS)-based 16S rRNA analysis. Bacterial culture was performed on solid media, and bacterial isolates were identified to the species level by MALDI-TOF MS. Species-dependent antimicrobial susceptibility testing was performed using single isolates and pools of isolates. Results: Bacterial richness in the nose increased numerically from 163 ± 30 to 243 ± 100 OTUs (gentamicin) and from 114 ± 17 to 144 ± 45 OTUs (ciprofloxacin). Phylogenetic diversity index (pd) of different bacterial strains in the nasal microbiome increased from 12.4 ± 1.0 to 16.9 ± 5.6 pd (gentamicin) and from 10.2 ± 1.4 to 11.8 ± 3.1 pd (ciprofloxacin). Unpreserved povidone eye drops resulted in minimal changes in bacterial counts. Preservative-containing povidone eye drops resulted in no change. A minor increase (1–2-fold) in the minimal inhibitory concentration (MIC) was observed in single streptococcal isolates. Conclusions: Antibiotic eye drops could affect the nasal microbiome. After an instillation period of seven days, an increase in the diversity and richness of bacterial strains in the nasal microbiome was observed. Full article