Objectives: Campylobacter jejuni is one of the most common causative agents of gastroenteritis; however C. jejuni meningitis is rarely described. Therefore, little is known about its epidemiology, clinical presentation, diagnostic methods, treatment, and outcomes. Methods: In this paper, we report a case of an adult patient with C. jejuni meningitis. In addition, we reviewed 16 cases of C. jejuni published since 1980. Results: We described a 62-year-old immunocompromised patient with meningitis and gastroenteritis in whom C. jejuni was rapidly detected in cerebrospinal fluid (CSF) using 16S rDNA, while blood culture yielded the same pathogen with 48 h delay. Following 21 day-long treatment with meropenem, our patient fully recovered. Literature review revealed that C. jejuni meningitis is mainly described in newborns and adults with central nervous system comorbidities and it is most frequently detected by bacterial cultures. Conclusion: There are no clear recommendations for antimicrobial treatment of C. jejuni meningitis, but meropenem seems to be a safe and effective choice. High hopes are placed in new, broad-range culture-independent molecular methods that enable rapid pathogen detection, even in case of negative cultures.

Campylobacteriosis is the most common gastrointestinal bacterial disease in the European Union (EU). Wild birds are one of the natural reservoirs of these pathogens. In this study we tested cloacal swabs of 643 gulls captured on rubbish tip in Zagreb, Croatia for the presence of Campylobacter spp. and found 168 Campylobacter positive samples. We used multilocus sequence typing (MLST) to genotype 62 random C. jejuni isolates from gulls, 24 isolates from broiler caeca, 27 isolates from broiler neck skins and 23 human isolates. Altogether, we identified 44 different STs, from which 19 were newly described. Most of the new STs (14) originate from gulls. Although humans and broilers share the majority of STs and isolates from gulls are separated from these, there was one ST present in all three hosts: 45. Additionally antimicrobial susceptibility to six antimicrobials was performed on 123 C. jejuni strains isolated from broiler caeca (n = 22), neck skins of broilers (n = 20), gulls cloacal swabs (n = 50) and human faeces (n = 31) by the broth microdilution method. Results show lower resistance of gull isolates to NAL and CIP, while resistance to TET was as high as in human and broiler isolates.

Campylobacteriosis represents a global health challenge due to continuously increasing trends of antimicrobial resistance in Campylobacter jejuni. C. jejuni can sometimes cause life-threatening and severe systematic infections (bacteremia, meningitis, and other extraintestinal infections) with very few antibiotics left as treatment options. Bearing in mind that C. jejuni is the predominant species in humans, in this paper, we present a study of the C. jejuni differences in antimicrobial resistance and genotype distribution between strains isolated from stool and primary sterile sites. We compared the genomic data obtained through whole genome sequencing (WGS) and phenotypic susceptibility data of C. jejuni strains. Once antimicrobial susceptibility testing of C. jejuni strains was carried out by the broth microdilution method for six of interest, results were compared to the identified genotypic determinants derived from WGS. The high rate of resistance to fluoroquinolones presented in this study is in accordance with national surveillance data. The proportion of strains with acquired resistance was 71% for ciprofloxacin and 20% for tetracycline. When invasive isolates were analysed separately, 40% exhibited MIC values of ciprofloxacin higher than the ECOFFs, suggesting a lower flouroquinolone resistance rate in invasive isolates. All isolates demonstrated wilde-type phenotype for chloramphenicol, erythromycin, gentamicin, and ertapenem. A special focus and review in this study was performed on a group of C.jejuni strains found in primary sterile samples. Apart from demonstrating a lower resistance rate, these isolates seem genetically more uniform, showing epidemiologically more homogenous patterns, which cluster to several clonal complexes, with CC49 being the most represented clonal complex.

In the era of growing antimicrobial resistance, a threat affecting humans, endangering animals, as well as livelihoods and food security worldwide, we wanted to find possible explanations for its continuous spread from a new perspective. The ubiquity of resistance genes requires a One Health approach to finding the explanations for continuous AMR spread. The natural transformability of Campylobacter jejuni, its high incidence of infections, and emerging resistance worldwide inspired us to choose C. jejuni ST-21CC to be our pathogen for analyzing its contribution and connection to the cycle of AMR dissemination. ST-21CC is known as a generalist among humans and broilers, the most prevalent lineage worldwide, but it is rarely found in wild birds. Emerging in wild birds, genetic relatedness and similar resistance profiles were expected. We analyzed 23 Croatian C. jejuni strains belonging specifically to ST-21CC from humans, broilers, and wild birds. The genomic data obtained through whole genome sequencing and phenotypic susceptibility data of strains were compared. Our findings suggest high fluoroquinolone resistance in ST-21CC strains, with more diverse genetic backgrounds in wild birds. Intriguing were three isolates of ST-822 (from human and storks), sharing a similar genetic fingerprint.

Rapid and accurate serotyping of Salmonella (S.) enterica subsp. enterica serovars is essential for effective public health surveillance, outbreak control, and food safety management. Traditional serotyping, although considered the gold standard, is time-consuming, technically demanding, and costly. This study aimed to evaluate the applicability of artificial intelligence (AI)-enhanced Fourier-transform infrared (FT-IR) spectroscopy using an IR Biotyper (Bruker Daltonics, Bremen, Germany) for the rapid and accurate serotyping of Salmonella enterica subsp. enterica isolates in Croatia. Materials and Methods: A total of 143 isolates representing different S. enterica serovars of human and food origin were analysed using the IR Biotyper. Each strain was tested in three biological and at least three technical replicates. The obtained results were compared with traditional serotyping according to the Kauffmann–White–Le Minor scheme. Isolate identification at the genus level was further confirmed by MALDI-TOF mass spectrometry. Results: The IR Biotyper demonstrated high reproducibility and complete concordance with standard serotyping methods, enabling accurate differentiation of the most prevalent S. enterica serovars in Croatia. Conclusions: Our findings demonstrate the applicability of FT-IR in routine laboratory work, with the potential to reduce typing time, reduce the number of strains, and lower overall costs required for epidemiological surveillance within the One Health approach.

Campylobacter jejuni is a leading cause of bacterial gastroenteritis worldwide which usually presents as mild, and self-limiting disease in immunocompetent individuals. However, in immunocompromised patients, such as those with common variable immunodeficiency, C. jejuni can cause severe recurrent infections requiring antibiotic treatment. Our study reports a case of a 37-year-old male patient with CVID, who had multiple episodes of C. jejuni intestinal infections over a 3.5-year period. A total of 27 stool samples were collected and analyzed between December 2020 and July 2024 during acute febrile diarrheal episodes, with C. jejuni isolated in 15 samples. Antimicrobial susceptibility testing (AST) during the course of the disease revealed three different antimicrobial resistance profiles including multi-drug-resistant phenotype. Whole genome sequencing was performed on three representative isolates, all identified as MLST type 367, ST-257 complex, with minimal genetic divergence, indicating a clonal origin. Genes and point mutations conferring resistance to macrolides, fluoroquinolones, beta-lactams, and tetracycline were identified in different C. jejuni isolates, along with key virulence factors linked to adherence, invasion, motility, and immune evasion. The genetic analysis of macrolide phenotypic resistance revealed different resistance mechanisms. Genotypic and phenotypic analyses of the same C. jejuni clone from single patient, and identified multidrug resistance pattern, present the first documented case of in vivo resistance development of C. jejuni in Croatia. This case highlights the role of prolonged antibiotic pressure in driving resistance evolution and underscores the need for careful antimicrobial stewardship and genomic monitoring in immunocompromised patients. Further research is needed to correlate phenotypic resistance with genetic determinants in Campylobacter spp.