Acta microbiologica et immunologica Hungarica最新文献

Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a growing threat in Greek hospitals, with increasing reports of multidrug- and pandrug-resistant strains; however, molecular data from regional centers remain limited. This study aimed to investigate the molecular epidemiology, resistance mechanisms, and transmission dynamics of CRKP isolates collected at the General Hospital of Volos, Central Greece, between 2022 and 2024. Thirty-seven non-duplicate CRKP isolates were analyzed. Identification and antibiotic susceptibility testing were performed using VITEK® 2, disk diffusion, Etest®, and broth microdilution. Carbapenemase production was assessed using the NG-Test® Carba-5. Eight isolates underwent multilocus sequence typing (MLST). All isolates were resistant to carbapenems, cephalosporins, and fluoroquinolones; furthermore, 40% were colistin-resistant. The dominant carbapenemase genes were blaNDM-1 (45.9%), blaKPC-2 (18.9%), and blaVIM-1 (27.0%), with co-expression of multiple carbapenemases in 30% of the isolates. MLST revealed the high-risk clones ST11, ST15, and ST323, and three intra-intensive care unit (ICU) transmission clusters. The emergence of dual-carbapenemase and colistin-resistant clones underscores the need for local genomic surveillance, improved infection control, and access to newer antimicrobials in non-tertiary settings.

Products of avian origin are one of the major Salmonella reservoirs, responsible for serious public health concerns. Transmission and pathogenicity are mainly caused by molecular mechanisms, including chromosomal and plasmid-encoded virulence factors. This study aimed to perform phenotypic identification, antibiotic resistance profiling against 15 antibiotics, and characterization of virulence factors of 80 Salmonella strains (30 from human and 50 from poultry), collected in Annaba and Constantine regions in Algeria.Antibiogram analysis and simplex PCR revealed complete resistance to four antibiotics: Ampicillin, Penicillin, Cephalotin and Cephoxetin. In addition, four virulence genes (spvA, spiC, spvC and pefA) were detected. These genes were identified in isolates from both avian and human origins, with variations in their distrubition frequencies. This study highlights the significant role of avian-derived Salmonella as a reservoir of antibiotic resistance and virulence genes, posing a serious threat to public health.Antibiotic resistance profiling revealed that avian isolates exhibited complete resistance (100%) to ampicillin, penicillin and cephalothin, followed by a high resistance rate of 98% to cefalexin and ceftriaxone. Moderate resistance levels, ranging from 76% to 46%, were observed against streptomycin, tetracycline, trimethoprim-sulfamethoxazole, ciprofloxacin, kanamycin and nalidixic acid. In contrast, low resistance rates were reported for gentamicin, amikacin, and chloramphenicol, at 20%, 18%, and 16%, respectively.On the other hand, human isolates showed complete resistance (100%) to ampicillin, penicillin, cephalothin and cefalexin. Moderate resistance (76%-46%) was observed against ceftriaxone, kanamycin, cefotaxime, gentamicin, trimethoprim-sulfamethoxazole, nalidixic acid, streptomycin, and chloramphenicol. Low resistance levels were detected for tetracycline, ciprofloxacin, and amikacin, at 26%, 20%, and 6.6%, respectively.These findings along with the widespread presence of virulence genes (spvA, spiC, spvC, and pefA) in both human and poultry isolates, underscore the potential for cross-species transmission and the urgent need for enhanced surveillance. The regional findings from Annaba and Constantine emphasize the importance of stricter antibiotic use policies in poultry farming.

The objective of our work is to identify antimicrobial-resistance genes and to analyze clonality of carbapenem-resistant Escherichia coli. A total of 75 carbapenem-resistant E. coli (CREco) strains were isolated in a Chinese hospital from January 2021 to May 2023. The antibiotic susceptibility testing was conducted by BD PhoenixTM M50 System and Kirby-Bauer disk diffusion method. Whole-genome sequencing was performed on Illumina NovaSeq 6000 platform. Antimicrobial resistance genes were identified based on NCBI with ABRicate 0.8. Multilocus sequence typing (MLST) analysis for CREco was performed. Among the 75 CREco strains in this study, the most of them were isolated from urine samples (n = 20, 26.67%) at the intensive care unit (n = 14, 18.67%). Among the detected carbapenem resistance genes, blaNDM-5 was the most prevalent (n = 57, 76.00%), followed by blaNDM-4 (n = 3, 4.00%), blaNDM-9 (n = 3, 4.00%), and blaNDM-1 (n = 2, 2.67%). In addition, the colistin resistance gene mcr-1.1 (n = 11, 14.67%) and the tigecycline resistance gene tetX4 (n = 2, 2.67%) were also detected. The results of MLST revealed 25 sequence types (STs), and ST410 (n = 17) was the dominant clone. Other major STs included ST167 (n = 12), ST156 (n = 10), ST361 (n = 5), and ST101 (n = 4). Overall, CREco strains exhibited a high-level resistance rate to commonly used antimicrobial agents, and the most of them carried various NDM-coding genes, with blaNDM-5 being the predominant type. In this study, we demonstrated the diversity of carbapenem-resistant E. coli; however, the major clone was ST410. These results also show the dissemination of different clones of carbapenem-resistant E. coli.

The widespread use of antimicrobial agents correlated with the increasing incidence of nosocomial infections and bacterial antibiotic resistance. These have become major challenges in the prevention and control of hospital-acquired infections worldwide. The aims of this study were to analyze the distribution and characteristics of ESKAPE pathogenic bacteria and their antibiotic resistance profile among clinical isolates from a tertiary hospital in China from 2018 to 2023. The results showed that a total of 20,472 non-duplicated pathogenic bacteria were isolated from clinical specimens in this hospital between 2018 and 2023, of which the top five pathogenic bacteria were Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii. In case of E. coli the main detected resistance genes were blaCTX-M, blaTEM and blaOXA. K. pneumoniae mainly carried blaOXA, blaKPC and blaNDM genes. P. aeruginosa was mainly positive for blaOXA, AmpC type beta-lactamases and blaVIM genes. A. baumannii mainly carried ArmA, blaTEM and cas3 genes. S. aureus was mainly positive for mecA, erm(C) and erm(A) genes. In this study, we have found that the antibiotic resistance of common pathogens from clinical isolates in a tertiary hospital in China in the past 6 years is severe, and A. baumannii was particularly a prominent pathogen. There is an urgent need to strengthen the prevention and control of nosocomial infections and antimicrobial drug management in order to curb the spread of multidrug-resistant bacteria.

Candida auris spreads rapidly and causes outbreaks worldwide. Strict infection control is critical to control its spread; however, it is challenging and requires a special approach. This study aims to investigate the colonization and infection of C. auris in intensive care units (ICUs), analyses its susceptibility, and mortality rates, and contributes to an effective infection control.An infection control study was planned, and a C. auris infection control bundle and checklist were developed. During the study's pre-intervention, intervention, and post-intervention periods, C. auris candidemia cases and colonized patients were identified. Until the infection control intervention, all the candidemia cases, antifungal resistance, and mortality were investigated retrospectively. Clinical isolates were identified by phenotypic and genotypic characterization using MALDI-TOF MS Biotyper (Bruker Daltonics, Bremen, Germany) and sequencing.During the pre-intervention, intervention, and post-intervention periods, 26 C. auris cases were identified. Pan-resistant C. auris isolates were 3.84%, and the multidrug resistance was 65.38%. With the infection control intervention, the number of colonized patients decreased (pre-intervention 9.61‰, intervention 6.19‰, post-intervention 5.20‰). Candidemia incidence decreased from 4.09 to 2.3‰. No new cases of candidemia were observed at the end of the study.The risk of new cases is elevated in the rooms where multiple C. auris cases have been previously isolated. Mortality rate was high; namely, 76.92% of patients died, and 19.23% of strains were resistant to anidulofungin, one of the most commonly used antifungals. Despite the short implementation period, the infection control bundle and checklist have been demonstrated to be effective in controlling C. auris spread in the ICU.

Multidrug resistant (MDR) gram-negative bacilli associated with hospital-acquired infections are commonly resistant to carbapenems. Klebsiella pneumoniae is a common MDR Enterobacterales in Thailand. In this study, we investigated the distribution of five carbapenemase genes (blaNDM, blaOXA-48, blaIMP, blaVIM, and blaKPC) among 62 carbapenem resistant K. pneumoniae (CRKP) collected in 2022 from patients admitted to a tertiary care hospital in Bangkok. The frequencies of isolates carrying a single carbapenamase gene were 39% for blaOXA-48 and 19% for blaNDM. Interestingly the frequency of the carriers of both genes was as high as 29% and none of the isolates carried blaKPC, commonly reported elsewhere. The studied genes were not identified in 7 isolates (11%). CRKP carrying blaNDM was more frequently identified in medical wards, associated with higher mortality rate and 100% resistant to ceftazidime/avibactam while the one carrying only blaOXA-48 was 92% susceptible to ceftazidime/avibactam. This study confirms the advantage of molecular methods for differentiating between mechanisms of carbapenem resistance in K. pneumoniae.

Helicobacter pylori is a major pathogen infecting over half of the global population, causing conditions like gastritis, ulcers, gastric cancer, and lymphoid tissue lymphoma. This study investigated the prevalence of H. pylori in 100 gastric biopsy samples from patients with dyspepsia and analyzed antibiotic resistance and virulence genes (cagA, vacA, iceA, and babA) using polymerase chain reaction (PCR). Diagnosis was performed via PCR, culture, rapid urease test, and histopathological examination, with antibiotic susceptibility assessed through the E-test method.The study was conducted between September 2022 and February 2023. The study found that 34% of samples were PCR-positive for H. pylori, while culture, histology examination, and rapid urease test showed positivity rates of 23%, 53%, and 63%, respectively. Alarmingly, antibiotic resistance was prevalent, with 100% resistance to clarithromycin and metronidazole, 39.1% to tetracycline, and 34.8% to levofloxacin. Virulence gene analysis revealed high positivity rates: cagA (53%), babA (29%), iceA1 (20.6%), iceA2 (41.2%), and vacA (97.1%), with the vacA s1m2 allele variant being most common (55.8%).These findings underscore the significant role of virulence factors like cagA and vacA in H. pylori pathogenesis and the severity of related diseases. The study highlights the urgent need for routine antimicrobial susceptibility testing to guide treatment amidst escalating antibiotic resistance. It also emphasizes the value of molecular diagnostics, such as PCR, for accurate and rapid detection of H. pylori and its virulence determinants. These insights are critical for improving the management of H. pylori-associated diseases and combating antibiotic resistance globally.

To identify antibiotic resistant genes and assess the clonality of carbapenem-resistant Enterobacter cloacae (CRECL) isolates from a hospital setting, altogether fifty-two clinical CRECL isolates were collected from 2012 to 2023. Antibiotic resistance genes including blaNDM, blaVIM, blaIMP, blaOXA-48, blaCTX-M-1 and blaTEM, were analyzed by PCR and nucleic acid sequencing. Sequence data were compared with those in the National Center for Biotechnology Information database. Clonality analysis was performed by ERIC-PCR. Among the 52 isolates, urine samples (23.1%) were the most common source, followed by puncture fluid (13.5%). The isolates were predominately obtained from urology (15.4%), followed by hepatobiliary surgery (11.5%). All isolates exhibited carbapenem resistance, with resistance rates of 88.5%, 84.6%, and 94.2% to imipenem, meropenem, and ertapenem, respectively. This was frequently accompanied by co-resistance to fluoroquinolones (67.2% to ciprofloxacin) and aminoglycosides (61.5% to tobramycin), likely due to the co-existence of multiple resistance genes on mobile genetic elements such as plasmids. However, all isolates remained sensitive to polymyxins, 67.2% to tigecycline and 50% to amikacin. Several carbapenem resistance genes were detected in isolates, with blaNDM-1 being the most abundant (40.4%), followed by blaNDM-5 (21.2%). Additionally, blaOXA-48 (3.8%), blaIMP-6 (1.9%) and blaVIM-1 gene (1.9%) have also been found in a few isolates. Among β-lactam resistance genes, blaTEM-1 (42.3%) is the most prevalent, followed by blaCTX-M-1 gene (23.1%). Clonality analysis classified the isolates into five clusters (A-E). Multiple strains exhibited >86% similarity, indicating clonal spread. In conclusion, CRECL isolates demonstrated extensive antimicrobial resistance, primarily mediated by blaNDM-1 and blaTEM. Clonality analysis revealed the presence of clonally related strains across different hospital departments, suggesting potential nosocomial transmission. Enhanced surveillance, strict disinfection and isolation measures are necessary to prevent the spread of CRECL and mitigate nosocomial infections and dissemination of epidemics.

In the food industry, one of the main challenges is providing products free from pathogens that cause high morbidity and mortality in consumers. This situation has been further aggravated by the emergence of antibiotic-resistant strains, with some notable examples such as extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC), due to their impact on the healthcare sector, causing difficult-to-treat infections. Therefore, the objective of this study was to evaluate the prevalence of ESBL-EC and their antibiotic resistance patterns in chicken meat sold in Tamaulipas, Mexico. A total of 130 chicken meat samples from 17 municipalities in Tamaulipas were analyzed during 2024. An average prevalence of 20.7% of ESBL-EC was detected. Thirty-eight different antibiotic resistance patterns were identified, and 85.1% were multidrug-resistant (MDR). When classifying the strains into phylogroups, 63.8% were considered commensal (groups A and B1) and 36.1% pathogenic (groups B2 and D). The results of this study demonstrate the presence of pathogenic MDR ESBL-EC strains in chicken meat sold in Tamaulipas, suggesting possible improper handling of this meat, which may pose a risk to consumers. These results also emphasize the need to monitor the presence of antibiotic resistant strains in chicken meat and other foods sold in Mexico.

Stenotrophomonas maltophilia is an opportunistic pathogen that can cause infections especially in hospital settings and in immunocompromised individuals. Due to its resistance to many broad-spectrum antibiotics, treatment options that can be used in clinical practice are limited. This study aims to evaluate the susceptibility profiles of S. maltophilia isolates to antimicrobial agents commonly used in treatment and to investigate the presence of different classes of integrons and sul genes responsible for resistance. The study included 100 S. maltophilia isolates from various clinical samples sent to Balıkesir University Health Practice and Research Hospital Medical Microbiology Laboratory between 2017 and 2023. The BD Phoenix™ M50 Automated System was used for bacterial identification and antibiotic sensitivity testing. The susceptibility of isolates to trimethoprim-sulfamethoxazole was also studied by disk diffusion method. All isolates were investigated for sul1, sul2 genes and integron-associated integrase genes by polymerase chain reaction. The susceptibility rates of isolates to trimethoprim-sulfamethoxazole, levofloxacin and ceftazidime were determined as 96%, 66% and 38%, respectively. Polymerase chain reaction results showed, intI1 and sul1 genes were found to be positive together in two isolates resistant to trimethoprim-sulfamethoxazole, while sul1 and sul2 genes were found in two separate isolates sensitive to trimethoprim-sulfamethoxazole. The intI2 gene was not detected in any isolate. This study addresses the clinically important problems of S. maltophilia infections, which are increasingly difficult to treat due to intrinsic and acquired resistance mechanisms. By providing valuable information on antimicrobial susceptibility and resistance profiles of S. maltophilia isolates, it contributes to national data and guides efforts to control resistance and promote rational antibiotic use.