Campylobacter infection in children and adults in Bulgaria: comparative characteristics and antimicrobial resistance

Figures & data

Table 1. Sequences of the primers and their amplicon sizes.

Target gene	Sequence	Amplicon size (bp)	References
cadF	F:5′- TTGAAGGTAATTTAGATATG-3′		Nayac et al., 2005 [14]
	R:5′-CTAATACCTAAAGTTGAAAC-3′	400
hipO	F:5′- GAAGAGGGTTTGGGTGGTG-3′		Linton et al., 1997 [15]
	R:5′-AGCTAGCTTCGCARAATAACTTG-3′	735
asp	F:5′- GGTATGATTTCTACAAAGCGAG-3′		Linton et al., 1997 [15]
	R:5′-ATAAAAGACTATCGTCGCGTG-3′	500

Figure 1. Results of capillary gel electrophoresis after Multiplex PCR analysis of clinical faecal samples from hospitalised patients with acute diarrhoea. Lanes 1 up to 9 and 11up to 13 - positive faecal samples for C. jejuni by detection of cadF (400 bp) and hipO (735 bp) genes. Lane 10- а positive faecal sample for C. coli by detection of cadF (400 bp) and asp (500 bp) genes. Lane 14 - C. jejuni ATCC 33560 as a positive control. Lane 15 - C. coli reference strain provided by WHO-EQAS 2016, SSI, Danmark as a positive control. Lane 16 - DNA ladder (50-2 000 kb).

Table 2. Distribution of campylobacteriosis among hospitalised patients at the University Hospital “Prof. Iv. Kirov” in Sofia for the studied period, 2018–2020.

Age group	Faecal samples	Campylobacter spp.	C. jejuni	C. coli	p-value
<5 years	400	172 (43.0%)	152 (88.37%)	20 (11.62%)
5-64 years	554	133 (24.0%)	156 (28.1%)	16 (2.88%)	p = 0.036
≥65 years	187	80 (42.78%)	71 (88.75%)	9 (11.25%)
Total	1120	285	340 (88.31%)	45 (11.68%)

Table 3. Clinical symptoms in patients by age groups.

Symptoms	<5 years of age n = 172	5-64 years of age n = 133	≥65 years of age n = 80	p-value
Diarrhoea	172 (100%)	132 (99.24%)	76 (95%)
Bloody diarrhoea	158 (91.86%)	81 (60.9%)	39 (48.75%)	p < 0.038
Abdominal pain	92 (53.48%)	110 (82.7%)	53 (66.25%)	p < 0.041
Vomiting	41 (23.83%)	39 (29.32%)	21 (26.25%)
Fever	172 (100%)	131 (98.5%)	52 (65%)	p < 0.033
Dehydration/demineralisation	161 (93.6%)	101 (75.93%)	78 (97.5%)

Table 4. Profiles of antimicrobial-resistant C. jejuni and C. coli isolates recovered from clinical faecal samples.

Antibiotic (µg)	Antibiotic-resistant strains in < 5years of age		Antibiotic-resistant strains in ≥ 65 years of age
	C. jejuni (n = 152)	C. coli (n = 20)	C. jejuni (n = 71)	C. coli (n = 9)
Tetracycline (30 µg) (T)ECOFF ≥ 30- C. jejuni (T)ECOFF ≥ 32- C. coli		61 (40.13%)		8 (40%) 30 (42.25%)
Ciprofloxacin (5 µg) (T)ECOFF ≥ 26- C. jejuni (T)ECOFF ≥ 27 C. coli	29 (19.07%)	1 (5%)	42 (59.15%)	1 (11.11%)
Erythromycin (15 µg) (T)ECOFF ≥ 22- C. jejuni (T)ECOFF ≥ 24- C. coli	–	–	2 (2.81%)	-
Azithromycin (15 µg) (T)ECOFF ≥ 20- C. jejuni (T)ECOFF ≥ 23- C. coli	–	–
Cross-resistance to Tetracycline + Ciprofloxacin	21 (13.81%)		19 (26.76%)
Resistant to one antibiotic – Tetracycline	40 (26.31%)		4 (5.63%)
Resistant to one antibiotic – Ciprofloxacin	8 (5.26%)	1 (5%)	15 (21.12%)	1 (11.11%)

Nayak R, Stewart TM, Nawaz MS. PCR identification of Campylobacter coli and Campylobacter jejuni by partial sequencing of virulence genes. Mol Cell Probes. 2005;19(3):187–193.

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Linton D, Lawson AJ, Owen RJ, et al. PCR detection, identification to species level, and fingerprinting of Campylobacter jejuni and Campylobacter coli direct from diarrheic samples. J Clin Microbiol. 1997;35(10):2568–2572.

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Data availability statement (DAS)

The data are available upon reasonable request from the author for correspondence (V.V.)