International Journal of Microbiology最新文献

Ureaplasma urealyticum and Mycoplasma hominis are significant causes of genitourinary infections, with increasing concerns regarding their antimicrobial resistance (AMR) profiles. This study determined the infection rate and AMR profiles of U. urealyticum and M. hominis in genitourinary samples from patients at the National Hospital of Dermatology and Venereology, Vietnam. A retrospective analysis of 2207 samples collected from 2018 to 2022 was performed. Isolates were identified and tested for antibiotic resistance using standard methods. Data were analyzed using R software, and statistical associations were assessed using the Cochran-Armitage test. Of the 654 positive cultures, 43.3% were from males and 56.7% from females, with the 25-40 age group most affected (55.7%). U. urealyticum was the most prevalent isolate (97.6%), followed by M. hominis (28%), with 25.5% showing coinfection. Resistance rates varied significantly for U. urealyticum; ciprofloxacin resistance was highest (76%), while josamycin resistance was lowest (6.9%). M. hominis showed high resistance to ciprofloxacin (88%), erythromycin (79.2%), and ofloxacin (77%). Coinfections of both species also displayed similarly high resistance patterns. Our study underscores the need for ongoing surveillance of U. urealyticum and M. hominis. We found that U. urealyticum was the predominant pathogen, with resistance patterns differing by species. M. hominis exhibited higher resistance overall, while josamycin remained a relatively effective treatment option. Notably, ciprofloxacin resistance was high across all isolates. These findings highlight the urgency and importance of continuously monitoring these pathogens and their resistance profiles.

Background: Since antimicrobial resistance is a rising danger and a serious threat to the health of humans, recent studies have revealed that routine tests, such as minimum inhibitory concentration (MIC), are not enough to detect heteroresistance (HR) phenotype (i.e., phenotypic heterogeneity in antibiotic susceptibility in the identical bacterial population), and medical laboratories require awareness raising to face it. Colistin is regarded as the final therapeutic option for infections caused by carbapenem-resistant gram-negative bacteria. In this study, we explored the presence of HR to colistin in carbapenem-resistant Pseudomonas aeruginosa isolates in Iran.

Methods: From 2019 to 2020, 100 P. aeruginosa clinical isolates were gathered from hospitals in various regions in Iran. In the present study, antibiotic susceptibility testing was used to determine antibiotic resistance. The population analysis profile (PAP) test was conducted to measure HR. Additionally, PCR was carried out to detect metallo-β-lactamase genes, including bla _NDM-1 and bla _IMP, and bla _VIM genes of colistin heteroresistant isolates.

Results: As a result, of the 100 P. aeruginosa isolates that were tested by AST, 66 were resistant to carbapenem antibiotics. Here, we found that 62 carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates were susceptible to colistin, while four isolates were resistant to colistin. Regarding the PAP assay, we identified eight heteroresistant isolates, of which three and two isolates carried bla _NDM-1 and bla _IMP genes, respectively. Furthermore, the HR isolates demonstrated a stable phenotype after seven subcultures in Mueller Hinton agar (MHA) without antibiotics.

Conclusions: Finally, our study highlights the interplay between HR and its diagnosis methods. Since it is difficult to detect heteroresistant isolates by routine tests in clinical laboratories, it might be misclassified as susceptible and lead to challenges for clinicians and their patients.

Antimicrobial resistance remains a global concern, and there has been sustained exploration of natural products with therapeutic effects. Endophytes are among the potential microorganisms considered as the treasure chest for bioactive secondary metabolites with therapeutic effects. The current study was aimed at evaluating the antibacterial activity of endophytic Bacillus subtilis isolated from selected Ethiopian medicinal plants (Kalanchoe petitiana, Artemisia abyssinica, Rumex abyssinicus, and Clematis longicauda). Collection of the plant samples, endophyte isolation, metabolite production, and antimicrobial activities were conducted following standard protocols. The isolates were further identified at the molecular level using 16S rRNA gene sequence. The endophytic crude extract demonstrated inhibition zones (millimeter) ranging from 6.00 ± 0.00 against Pseudomonas aeruginosa to 22.00 ± 0.71 against Salmonella Typhimurium. In general, S. Typhimurium was the most sensitive, followed by Escherichia coli, but P. aeruginosa was the least sensitive to the extracts. The extract from isolate En6 produced the largest inhibition zone against Staphylococcus aureus, but the extract from Ch1 produced pronounced inhibition against E. coli, S. Typhimurium, and P. aeruginosa. The lowest minimum inhibitory concentration and minimum bactericidal concentration values ( $\overline{x}\pm \text{SD}$ in milligram/milliliter) of 0.025 ± 0.01 and 0.98 ± 0.01, respectively, were recorded against S. Typhimurium by the extract from isolate Ch1. Molecular characterization confirmed that the isolates were members of B. subtilis. This is the first report of the isolation of endophytes with antibacterial activities from the Ethiopian medicinal plants. The strong inhibitory activity of the metabolites against the selected test bacteria shows the potential of the endophytic metabolites for use as antibacterial agents with further studies.

Background: Melioidosis is a challenging disease to diagnose, and diagnostic complications can delay treatment, adversely impacting patient outcomes.

Methods: Over a period of 1 year, 68 isolates, initially identified as Burkholderia spp. or oxidase-positive nonfermenting Gram-negative bacilli (excluding Pseudomonas aeruginosa), were collected from laboratories in three Colombian cities. Four commercial identification systems were employed. After recovery on blood agar, all strains were cultured on Ashdown's and CHROMID Colistin R media. Comparative identification using automated systems was performed, and definitive identification was achieved through multiplex PCR.

Result: PCR identified three Burkholderia pseudomallei isolates and 59 Burkholderia cepacia complex isolates. The Microscan and Vitek 2 Compact systems successfully identified the B. pseudomallei isolates, whereas the Phoenix and MALDI-TOF Bruker systems did not. Ashdown's CHROM colistin media supported the growth of B. pseudomallei and various other genera and species. Species-level misidentifications were frequent.

Conclusion: Due to limitations of commercial identification systems and the morphological similarities between species, the use of molecular tools or a combination of confirmatory tests is crucial for accurately diagnosing B. pseudomallei in Colombia.

Antimicrobial resistance (AMR) is a global public health emergency attributed to the inappropriate use of antimicrobial agents in human health, animal health, and environmental sectors. With low awareness regarding the consequences of antimicrobial use in livestock farming, improper slaughter practices, and unhygienic meat sales, AMR is circulating through the food chain. The study is aimed at unraveling the scenario of AMR and detecting resistant genes in Escherichia coli in meat and meat products in the market of Kathmandu. A total of 120 meat samples, n = 30 chicken meat, n = 30 buffalo meat, and n = 60 frozen meat products were sourced by random sampling between January and June 2024. Then, 54 isolates recovered from the meat samples were identified as containing E. coli based on conventional PCR analysis targeting the 16S rRNA gene of E. coli. Antimicrobial susceptibility tests revealed 57.4% of the isolates were resistant to tetracycline, followed by ampicillin (44.4%), trimethoprim-sulfamethoxazole, and ciprofloxacin (38.8%). Then, 44.4% of the isolates out of 54 were found to be multidrug-resistant. ESBL testing showed that seven E. coli isolates were ESBL producers, and upon colistin agar MIC test, two isolates were resistant to colistin. Conventional PCR analysis for the detection of ESBL-encoding genes confirmed that L4B and L17B contained both bla_CTX and bla_TEM-52 ESBL-encoding genes. Isolates L11B, L15B, and L8C harbored bla_CTX , while L12B and FZ100 harbored bla_TEM-52 ESBL-encoding genes. E. coli isolates L9C and FZ102 both harbored mcr-1 colistin-resistant genes, while mcr-2 was not observed. Carbapenem-resistant isolates were not recovered in the study. Isolation of multidrug-resistant E. coli, as well as the presence of ESBL and colistin-resistant genes, probably signifies misuse of antimicrobial agents in veterinary practices as well as cross-contamination due to poor hygiene practices. These actions pose a threat to the health of consumers and assist in the spread of AMR genes across microbial populations. Thus, regulatory bodies need to regulate the antimicrobial usage for veterinary applications and promote good hygiene practices in food processing industries, along with the dissemination of awareness to stakeholders regarding AMR.

Klebsiella variicola is a Gram-negative bacillus belonging to Enterobacteriaceae recognized as an emerging human pathogen in the last years. The species is frequently misidentified as Klebsiella pneumoniae by conventional microbiological tests, raising questions about its real prevalence and clinical impact. K. variicola virulence is mediated by traits that are expressed in human body niches containing different nutrients, including carbohydrates, that influence their expression. In this way, we analyzed the effect of different carbohydrates on the expression of virulence traits by K. variicola isolates. For this approach, three classical strains (cKv15, cKv35, and cKv57) and one hypermucoviscous (HMV) were submitted to growth curve characterization, biofilm production and serum survival assays, siderophores, and mrkA (encoding MRK adhesin) RNA quantification. The strains were cultivated in broth containing specific carbohydrates as the sole carbon source to perform the assays. Among all carbohydrates tested, sorbitol, galactose, and maltose were the most effective in promoting biomass production in biofilm for the K. variicola classical strains (cKv). Additionally, bacterial incubation in these carbohydrates resulted in the production of siderophores by all strains (cKv and HMV). Notably, cKvs cultivated in all carbohydrates tested survived and proliferated in human serum, while also producing high concentrations of siderophores and biofilm biomass. Except for siderophore production, HMV did not present any virulence trait tested (biofilm production, serum survival, and mrkA expression). However, its growth in media supplemented with galactose promoted serum survival. These observations indicate cKv isolates were able to use sorbitol, galactose, and maltose for rapid proliferation and to express determinants associated with bacterial colonization (as biofilm production, siderophores, and serum survival). The hypermucoviscosity of HMV did not promote biofilm and siderophore production. For this strain, galactose promoted survival in human serum. Altogether, the results highlight the role of galactose in promoting virulence in K. variicola.

Escherichia coli is a highly diverse bacterial species that is canonically commensal; however, its genomic characteristics have enabled its evolution into pathogens capable of causing extraintestinal infections (ExPEC), which pose significant clinical challenges because of the variety of sites that can infect (mainly the urinary tract) and the multidrug resistance associated with these strains. The present study is aimed at characterizing ExPEC isolates recovered from the wards of a hospital in Sinaloa, Mexico, to establish their virulence and antimicrobial resistance profiles, as well as the phylogenetic group. Then, 200 Escherichia coli isolates and their antimicrobial susceptibility were confirmed by the VITEK-2 automated system. Virulence factor genes and phylogenetic grouping were performed through endpoint and multiplex PCRs. Then, 59% of the strains produced extended-spectrum β-lactamases (ESBLs), and 71.5% were classified as multidrug resistant (MDR), exhibiting high resistance rates to antibiotics such as amoxicillin, ampicillin, ciprofloxacin, and various cephalosporins. In this sense, 68.5% and 33% of the isolates were positive for the blaCTX-M1-8 and blaCTX-M9 genes, respectively, both associated with resistance to cefotaxime. Furthermore, 37% of the isolates harbored the blaOXA48 gene, which is linked to resistance to oxacillin-type β-lactams. Moreover, 143 (71.5%) of them were classified as MDR. Regarding virulence, the distribution of toxin genes such as hlyA and vat was 16.5% and 24.5%, respectively. Adhesins papC and fimA were found in 62% and 34%, respectively. Additionally, the iron acquisition systems and outer membrane proteins such as iutA (74%), fyuA (63%), iroN (10%), agn43 (82%), and kpsmTII (34.5%) were present in the isolates. Phylogenetic analysis showed a predominance of group B2 (46%), followed by groups A (13.5%) and E (10.5%). These findings highlight the complexity and challenges posed by ExPEC strains in terms of antimicrobial resistance and virulence relevant to public health in hospital settings.

Carbapenems are critical for treating patients infected with multidrug-resistant bacteria; however, the use of carbapenems has also facilitated the selection and spreading of carbapenem-resistant organisms (CROs), occasionally reported in healthcare settings. The study examined the CRO prevalence among healthcare workers (HCWs), orphan children patients, and the environment in an orphanage healthcare facility in Vietnam. A cross-sectional study was performed by collecting rectal swabs in 20 HCWs and 67 orphan patients, as well as in 175 randomly selected environmental samples. Chromogenic CARBA agars, blood agars, and a BD Phoenix Automated Microbiology System were employed for bacterial isolation and for identification and testing of antimicrobial susceptibility. In a total of 262 samples, 36 CROs (i.e., six carbapenem-resistant Enterobacterales [CRE] and 30 non-CRE) were detected. The CRO prevalence of 30.0% (6/20), 16.4% (11/67), and 10.86% (19/175) was shown in HCWs, orphan patients, and the environment, respectively. Most CROs detected in HCWs were CREs (66.7%, 4/6). Non-CRE cases, mainly Acinetobacter baumannii, were detected in orphan patients and in the orphanage healthcare environment. Out of 36 CRO isolates, 97.2% (35/36), 11.1% (4/36), and 13.9% (5/36) were identified as resistant to ertapenem, imipenem, and meropenem, respectively. This study was the first to show evidence-based CRO colonization with an epidemiological study in an orphanage healthcare facility in Vietnam. The finding of this study suggested that control and prevention programs, active surveillance, and routine monitoring for CROs should be implemented in healthcare establishments.

The concentrations of heavy metal salts (Pb, Cd, Co, and Zn), which have an inhibitory effect on the growth of Bacillus bacteria, were determined using the method of successive dilutions. The dynamics of changes in the pH of the nutrient medium during bacterial cultivation with metal salts were analyzed. Bacterial growth phases were identified before and after exposure to minimally suppressive concentrations of these heavy metals. Atomic adsorption analysis was used to measure the amount of Zn, Co, Cd, and Pb accumulated by the bacteria from the medium. Both the supernatant and the biomass were analyzed at the onset of the stationary phase of microorganism growth. The effect of these elements on the morphology of bacteria was investigated using atomic force microscopy, and FTIR spectroscopy revealed differences in the shape of metals accumulated by bacteria.

Pathogenic drug-resistant yeast species, associated with urogenital infections, are still not well-recognized in routine clinical laboratories. This study describes the prevalence and antifungal susceptibility profile of fungal species isolated from patients with urogenital infection in Nsukka, Nigeria. A total of 248 urogenital samples (voided urine, high vaginal swabs, urethral swabs, and semen) were cultured on specific mycological media for the isolation and presumptive identification of Candida and other yeast species. Further identification of fungal isolates was performed using conventional phenotypic techniques and molecular methods. Disk diffusion and broth dilution methods were used for the antifungal susceptibility study and determination of minimum inhibitory concentration (MIC), respectively. A total of 129 yeasts were isolated from 117 patients with urogenital infection. Candida albicans (73.64%) was the most prevalent species followed by Pichia kudriavzevii (Candida krusei) (9.30%) and Candida parapsilosis (6.20%), while Nakaseomyces glabrata (Candida glabrata) and Candida tropicalis exhibited the same frequency of occurrence (5.43% each). All Candida isolates were susceptible to voriconazole and nystatin, while reduced susceptibility to fluconazole was noted. All the germ tube-positive isolates were confirmed to be C. albicans by molecular methods although 15 of them were found to be heterozygous at hwp1 locus. This study describes the distribution of true Candida species causing urogenital infection in Nigeria and the level of susceptibility of these species to common antifungal drugs emphasizing the need for yeast culture and antifungal susceptibility testing as part of the routine test in medical diagnostic laboratories for the proper management of urogenital candidiasis.