Risk of zoonoses involving slow-growing non-tuberculous mycobacteria: Survey of antimicrobial resistance among strains from domestic and wild animals

OBJECTIVES

Non-tuberculous mycobacteria are opportunistic pathogens that cause disease mainly in immunocompromised hosts. The present study assessed the prevalence of antibiotic resistance among such mycobacteria from domestic and wild animals in Croatia sampled during several years within a national surveillance program.

METHODS

A total of 44 isolates belonging to nine slow-growing species were genotyped and analyzed for susceptibility to 13 antimicrobials often used to treat non-tuberculous mycobacterial infections in humans.

RESULTS

Most prevalent resistance was to moxifloxacin (77.3%), doxycycline (76.9%), and rifampicin (76.9%), followed by ciprofloxacin (65.4%), trimethoprim-sulfamethoxazole (65.4%), and linezolid (61.4%). Few isolates were resistant to rifabutin (7.7%) or amikacin (6.8%). None of the isolates was resistant to clarithromycin. Nearly all isolates (86.4%) were resistant to multiple antibiotics.

CONCLUSION

Our findings suggest substantial risk that human populations may experience zoonotic infections with non-tuberculous mycobacteria that will be difficult to treat using the current generation of antibiotics. Future work should clarify how resistance emerges in wild populations of non-tuberculous mycobacteria.

Antimicrobial Resistance in Rapidly Growing Nontuberculous Mycobacteria among Domestic and Wild Animals Emphasizing the Zoonotic Potential

Non-tuberculous mycobacteria (NTM) are opportunistic pathogens capable of causing infections in humans and animals. The aim of this study was to demonstrate the potential role of domestic and wild animals as a reservoir of multiple resistant, rapidly growing NTM strains representing a potential zoonotic threat to humans. A total of 87 animal isolates belonging to 11 rapidly growing species (visible colonies appear within three to seven days) were genotyped and tested for susceptibility to the 15 most commonly used antibiotics in the treatment of such infections in a human clinic. By determining the antimicrobial susceptibility, the most prevalent resistance was found to cephalosporins (>50%), followed by amoxicillin-clavulanate (31.0%), clarithromycin (23.0%), tobramycin (14.9%) and doxycycline (10.3%). Resistance to imipenem, ciprofloxacin, minocycline and linezolid was notably lower (<7.0%). All tested isolates were susceptible to amikacin and moxifloxacin. The most frequent resistance was proved in the most pathogenic species: M. fortuitum, M. neoaurum, M. vaccae and M. porcinum. Meanwhile, other species displayed a higher sensitivity rate. No significant resistance differences between domestic and wild animals were found. The established significant frequency of resistance highlights the significant zoonotic potential posed by circulating rapidly growing NTM strains, which could lead to challenges in the treatment of these infections.

Antimicrobial resistance profiles of human Brucella melitensis isolates in three different microdilution broths: First multicentre study in Bosnia and Herzegovina

BACKGROUND

Brucellosis is a ubiquitous emergent bacterial zoonotic disease causing significant human morbidity in Bosnia and Herzegovina. So far, a high rate of resistant Brucella has been found worldwide. This study prospectively analysed the rates of resistance among human Brucella melitensis (B. melitensis) strains isolated in Bosnia and Herzegovina.

METHODS

This study included 108 B. melitensis isolates from 209 patients diagnosed at five medical centres in Bosnia and Herzegovina. The resistance profiles of the B. melitensis isolates for the 13 most commonly used antimicrobials were studied in standard Brucella broth (BB) and cation-adjusted Mueller-Hinton broth (CAMHB) supplemented with 4% lysed horse blood or 5% defibrinated sheep blood.

RESULTS

Of the 209 patients, B. melitensis blood cultures were positive for 111 (53.1%). Among the 108 isolates investigated, 91 (84.3%) were resistant to trimethoprim-sulfamethoxazole on BB, but not on either CAMHB. Nearly all isolates (>90%) were resistant to azithromycin on BB and both CAMHBs.

CONCLUSIONS

We observed a high rate of B. melitensis resistance to azithromycin. The high rate of resistance to trimethoprim-sulfamethoxazole that we observed was related to BB, so an alternative broth should be used, such as the enriched CAMHBs in this study, for evaluating resistance to trimethoprim-sulfamethoxazole. Whole-genome sequencing studies are needed to understand the development of antimicrobial resistance in B. melitensis strains isolated from humans.

The first report of Brucella melitensis Rev.1 human brucellosis in Bosnia and Herzegovina

Brucellosis is an emergent and endemic zoonotic disease in Bosnia and Herzegovina. In this report we have diagnosed the first case of human brucellosis in Bosnia and Herzegovina, using molecular and microbiological tests, caused by live attenuated Brucella melitensis Rev.1 strain. The infection was caused through unintentional exposure to vaccination of small ruminants in Bosnia and Herzegovina and without any prior accidental self-injection of vaccine suspension.

Distribution and elimination of levamisole in eggs and tissues after oral administration to laying hens, determined by LC-MS/MS

Levamisole was administered to laying hens, and concentrations in eggs and tissues (thigh muscle, breast muscle, liver and kidney) were determined by a newly developed liquid chromatography tandem mass spectrometry method, which allowed trace level quantification of levamisole. The adopted analytical method showed good sensitivity, repeatability and percentage of recovery from spiked matrices. Maximum concentrations of levamisole were found on the first day after the administration (531.1 μg/kg in liver, 164.3 μg/kg in egg yolk, 130.7 μg/kg in kidney, 78.0 μg/kg in breast muscle, 70.7 μg/kg in thigh muscle and 64.0 μg/kg in egg white), after which there is a decline. The compound was rapidly eliminated from eggs, with a half-life of 1.3 days. Elimination appeared to be slower in thigh muscle (3.5 days), breast muscle (3.4 days) and liver (3.3 days). According to this experiment, the levamisole withdrawal periods calculated for eggs, liver, kidney, breast muscle and thigh muscle in laying hens were 14.1, 6.1, >4.0, 14.5 and 13.0 days, respectively. The longest time for levamisole residues to be completely released from tissues was seen in liver samples (37.4 days), followed by thigh muscle, breast muscle and kidney. Elimination from eggs was fastest (16.4 days for levamisole residues to drop below the method quantification limit).

Epidemiological, Clinical and Molecular Characterization of Human Brucellosis in Bosnia and Herzegovina - An Ongoing Brucellosis Outbreak

OBJECTIVE

The aim of this study was to evaluate an ongoing outbreak of brucellosis in southern region of Bosnia and Herzegovina (BIH) on the epidemiological, clinical and molecular level.

PATIENTS AND METHODS

This study included 19 patients affected by brucellosis between 2015 and 2017, in Trebiševo (BIH). Out of 19 patients, 16 were admitted to and treated at the Department of Infectious diseases of the University Clinical Hospital Mostar, while three patients were treated in ambulatory care setting. Epidemiological, clinical and microbiological parameters were investigated. The Rose Bengal test (RBT) positive sera were serologically confirmed by complement fixation test (CFT). We also analyzed blood cultures, and isolates were additionally serotyped. Molecular analyses were performed with Bruce-ladder multiplex polymerase chain reaction (PCR) and multiple locus variable number of tandem repeat analysis of 16 loci (MLVA-16) assay.

RESULTS

Fifteen out of 19 patients had been professionally exposed to the bacterium, while four patients acquired brucellosis without prior contact with infected animals. In seven out of eight (87.5%) patients with localized form of brucellosis, we detected significantly higher values of C-reactive protein (CRP) or erythrocyte sedimentation rate (P<0.001). B. melitensis was isolated from 13/16 (81.3%) blood culture samples, and additionally serotyped as biovar 3. Using MLVA16 assay, 11 isolates were genotyped. We observed complete genotype matches among 8/11 B. melitensis isolates, while 3/11 isolates differed in Bruce04 locus.

CONCLUSION

Overall, our study confirms the usefulness of MLVA-16 method in the epidemiological and molecular research of brucellosis during epidemic that, most likely, originated from the same source.

Estimation of the Withdrawal Time of Levamisole in Eggs after Oral Administration to Laying Hens

This study was conducted to evaluate withdrawal time of levamisole in eggs after oral administration in laying hens at different doses. Sampling of eggs was conducted for 37 days after the end of treatment, and levamisole concentrations were measured by liquid chromatography-tandem mass spectrometry validated according to the Commission Decision 2002/657/EC. Estimated validation parameters were as follows: decision limit, 0.54 μg/kg; detection capability, 0.56 μg/kg; limit of detection, 0.04 μg/kg; limit of quantification, 0.15 μg/kg; accuracy (recovery), between 92.9 and 102.3%; precision (relative standard deviation), ≤4.62%; and within-laboratory precision (relative standard deviation), ≤5.19%. Levamisole residue levels were significantly higher in egg yolks than in egg whites. The highest levels of levamisole were detected on day 2 posttreatment in groups receiving 50 mg/kg of body weight (556.2 μg/kg in egg yolks and 166.5 μg/kg in egg whites). Significant elimination occurred within 5 days after the cessation of treatment in all groups, with an elimination half-life of 1.3 days. Levamisole was still detectable on day 30 after the end of treatment in egg whites (0.06 μg/kg) and on day 37 in egg yolks (0.06 μg/kg). The longest withdrawal time for levamisole in eggs (14.9 days) was determined in a group treated with 25 mg of levamisole per kg of body weight for two consecutive days. According to the results, oral treatment of laying hens with levamisole may result in noncompliant egg samples even 14 days after treatment.

Molecular epidemiology of Brucella melitensis strains causing outbreaks in Croatia and Bosnia and Herzegovina

The most recent data on the incidence of brucellosis in Southeast Europe prove the persistence of this zoonosis in the area, regardless of constant efforts at controlling it as one of the most dangerous zoonoses. Forty-three Brucella melitensis strains were collected from cattle, sheep, goats and humans from Croatia as well as Bosnia and Herzegovina between 2009 and 2015. The strains were identified and genotyped in order to determine their epidemiological background. Standard biotyping methods and Bruce-ladder were used to identify the strains. Genotyping was done using multilocus variable number tandem repeats analysis (MLVA) on 16 and multilocus sequence typing analysis (MLST) on nine loci. Results were compared to each other and to internationally available data. Twenty- five novel genotypes and two sequence types were identified. All tested strains, apart from vaccine and reference strains, showed very close phylogenetic and geographic relationships. The genotyping results indicate the endemicity of brucellosis in this region. MLST showed no variation, confirming the stability of housekeeping genes. The results confirm already established routes of disease spread in this area, showing that a more detailed and vigorous control of this zoonosis is necessary.

Prevalence of Thermotolerant Campylobacter spp. in Chicken Meat in Croatia and Multilocus Sequence Typing of a Small Subset of Campylobacter jejuni and Campylobacter coli Isolates

In order to detect thermotolerant Campylobacter spp., 241 samples of fresh chicken meat, at retail in Croatia, were analysed according to a standard method, followed by biochemical test and molecular polymerase chain reaction/restriction enzyme analysis for exact species determination. Campylobacter spp. prevalence was 73.86%. Campylobacter jejuni and Campylobacter coli were isolated from 53.53 and 15.35% of the samples, respectively. In 4.98% of isolates thermotolerant Campylobacter spp. were not determined. The multilocus sequence typing method was used to evaluate genetic diversity of eight Campylobacter jejuni and four Campylobacter coli isolates. To our knowledge, these results of genotyping provided the first data on the presence of sequence types (STs) and clonal complexes (CCs) of Campylobacter jejuni and C. coli isolates in Croatia. By applying the multilocus sequence typing, a new allele of tkt gene locus was discovered and marked tkt508. The C. jejuni ST 6182 and C. coli ST 6183 genotypes were described for the first time, and all other identified genotypes were clustered in the previously described sequence types and clonal complexes. These findings provide useful information on the prevalence and epidemiology of Campylobacter jejuni and C. coli in Croatia.

Evidence of Brucella strain ST27 in bottlenose dolphin (Tursiops truncatus) in Europe

Marine mammal brucellosis has been known for more than 20 years, but recent work suggests it is more widespread than originally thought. Brucella (B.) pinnipedialis has been isolated from pinnipeds, while B. ceti strains have been associated with cetaceans. Here we report a Brucella strain isolated from multiple lymph nodes of one bottlenose dolphin (Tursiops truncatus) during routine examination of dolphin carcasses found in the Croatian part of the northern Adriatic Sea during the summer of 2015. Classical bacteriological biotyping, PCR-based techniques (single, multiplex, PCR-RFLP) and 16S rRNA DNA sequencing were used to identify Brucella spp. Multiple-locus variable number tandem repeat analysis of 16 loci and multilocus sequence typing of 9 loci were used for genotyping and species determination. The combination of bacteriological, molecular and genotyping techniques identified our strain as ST27, previously identified as a human pathogen. This report provides, to our knowledge, the first evidence of ST27 in the Adriatic Sea in particular and in European waters in general. The zoonotic nature of the strain and its presence in the Adriatic, which is inhabited by bottlenose dolphins, suggest that the strain may pose a significant threat to human health.

First evidence of Brucella ovis infection in rams in the Pirot Municipality, Serbia

This paper describes a research on Brucella ovis infection in rams in the Pirot Municipality of South Serbia. A positive result with indirect immunoenzyme test (i-ELISA) was confirmed in 67 (29.8%) and suspicious in 31 (13.8%) out of 225 tested rams. Complement fixation test (CFT) was used as a confirmation test on 67 ELISA positive sera and gave positive reaction in 41 (61.2%) ram serum samples. Rams originated from 113 flocks with 4751 sheep, from 28 villages in the Pirot Municipality of southern Serbia. Clinical examination was performed on epididymis and testes of 12 rams from 7 seropositive flocks by inspection and palpation. The examination showed scrotum asymmetry and unilateral increase of the epididymistail in 5 (41.7%) out of 12 seropositive rams. Pathomorphological examination of testes and epididymis confirmed pathological changes in 7 (58.3%) of the 12 examined rams. Onesided epididymitis with pronounced hypertrophy of the epididymitis was also confirmed. Twelve rams were tested for the presence of bacteria, i.e. 21 epididymis, testes and lymph nodes samples. We isolated 20 Brucella strains from 11 (91.7%) of the 12 examined animals. All isolates were identified with bacteriological and molecular techniques as B. ovis. This is the first evidence of ovine epididymitis (B. ovis) in Republic of Serbia.

Distribution and Molecular Characterization of Hepatitis E virus in Domestic Animals and Wildlife in Croatia

Hepatitis E is becoming a growing health concern in European countries as an increase of sporadic human cases of unknown origin has been recorded lately. Its causative agent, Hepatitis E virus (HEV), is known to have zoonotic potential and thus the role of domestic and wild animals in the chain of viral spread should be considered when investigating risk factors and the epidemiology of the disease. A comprehensive survey based on viral RNA detection was carried out in Croatia including blood, spleen and liver samples originating from 1816 different domestic and wild animals and digestive gland samples from 538 molluscs. A high HEV prevalence was detected in domestic pigs (24.5%) and wild boars (12.3%), whereas cattle, molluscs, ruminant and carnivore wildlife samples tested negative. Molecular characterization of both ORF1 and ORF2 genomic regions confirmed the phylogenetic clustering of the obtained sequences into genotype 3, previously reported in Europe. Furthermore, our results proved the presence of identical sequence variants in different samples, regardless of their origin, age or habitat of the host, suggesting transmission events between domestic swine, as well as between domestic swine and wild boars in the country. Moreover, a close genetic relationship of Croatian animal strains and known human HEV strains from GenBank opens the question of possible cross-species HEV transmission in Croatia, especially in the areas with an intensive swine production.

Characterisation of Brucella suis isolates from Southeast Europe by multi-locus variable-number tandem repeat analysis

Porcine brucellosis is a common bacterial zoonosis which can cause significant financial losses. Its diverse and often complicated factors have hampered efforts to control disease spread. The aim of the study was to assess the epidemiological situation of porcine brucellosis primarily in Croatia and its relationship to genotypes present in other, mostly European countries. One hundred and seven Brucella suis strains isolated from swine, hares, cattle, humans, wild hares, a wild boar and a mare originating mainly from Croatia (112), but also a few from Slovenia, Bosnia and Herzegovina, Serbia and Macedonia (15) were tested using classical microbiological testing, Bruce-ladder, RFLP, Multiplex-suis and genotyped using multi-locus variable-number tandem repeat analysis (MLVA). We determined 43 Brucella suis genotypes. Strains were grouped according to phylogenetic and geographic relationships, revealing both regional specificity and uniqueness and suggesting possible sources and modes of spread among animals. Our study also confirmed problems with Bruce19 locus that may hinder comparisons of new types with those in the international database. Forty-one novel genotypes were identified and deposited into the international database. Our study supports the idea of wild animals as a source of disease in domestic animals and also gives evidence to hypothesis of cross-border animal trafficking between former Yugoslavian countries. It also highlights the need to expand such research across more of southeast Europe, especially to countries with poorer social and economical situation in order to prevent a realistic outbreak and for better understanding of the biology of this pathogen.

Mucocutaneous Inflammatory Pseudotumours in Simultaneous Mycobacterium avium subsp. avium and Mycobacterium avium subsp. hominissuis Infection in a Cat

Mycobacterial spindle cell 'pseudotumour' has been described only once in cats. This unique proliferation of spindle-shaped histiocytes containing Mycobacterium avium is associated with extensive subcutaneous lesions. We report mycobacterial pseudotumour with invasion of muscular and subcutaneous tissues in a 1-year-old female domestic longhair cat. Lesions involved the facial muscles and nasal cavity, making surgical excision impossible. Necropsy examination revealed additional nodules in the subcutis and muscles of the trunk and submandibular lymph nodes. Genotyping of organisms within these lesions revealed simultaneous infection with Mycobacterium avium subsp. avium and Mycobacterium avium subsp. hominissuis. The microscopical appearance of the granulomas was identical, regardless of the strain of bacterium or anatomical location.

Deposition and depletion of maduramicin residues in eggs after oral administration to laying hens determined by LC-MS

The coccidiostat maduramicin has been approved as a feed additive for chickens and turkeys, although it is prohibited for use in laying hens. In the present study, laying hens were divided into three groups and fed for 14 days with medicated feed containing maduramicin, at three different concentrations: 50, 100 and 500 µg kg(-1). Eggs were collected during treatment and for 26 days after the end of feeding with medicated feed. Maduramicin residues were found exclusively in egg yolk, with the highest concentration in egg yolk of 459 µg kg(-1) for the highest dose. The maximum concentration of maduramicin in whole egg was 16.6 µg kg(-1) for the group receiving feed containing the maximum permitted level of maduramicin in feed (50 µg kg(-1)). The half-life of elimination of maduramicin, calculated for post-treatment days 1-10, was 6.5 days. Twelve days after drug administration, the concentration of the maduramicin in egg yolk for Group 3 (fed with 500 µg kg(-1) maduramicin) still exceeded 20 µg kg(-1), while the concentrations for Groups 1 and 2 were 1.2 and 2.7 µg kg(-1), respectively.

Melitococcosis in the republic of croatia

BACKGROUND

Melitococcosis is one of the most widespread zoonoses worldwide. In the period from 2009 to 2013, comprehensive melitococcosis testing was conducted in the Republic of Croatia.

METHODS AND RESULTS

During the testing, the Rose Bengal test was applied to 344019 blood samples of sheep and goats, and positive reactions were confirmed in 1143 (0.3%) of samples. The complement fixation test (confirmatory test) was conducted on 43428 samples, with positive reactions confirmed in 768 (1.8%) of samples. The organs and tissues of 336 sheep and goats were inspected bacteriologically, and Brucella sp. was isolated in 15 (4.5%) of samples. Positive serological and bacteriological reactions were confirmed in the Karlovac, Lika-Senj and Split-Dalmatia Counties. Bacteriological and molecular techniques (Bru-up/Bru-low and Bruce-Ladder) in isolates proved the presence of Brucella melitensis biovar 3.

CONCLUSION

On the basis of this study, it can be concluded that Croatia has a favourable situation concerning the infection of ruminants with B. melitensis, and that ongoing controls of the disease are necessary.

The presence of methicillin-resistant Staphylococcus aureus on large pig breeding farms in Croatia

Methicillin-resistant Staphylococcus aureus (MRSA) have emerged worldwide and have become resistant to a variety of antibiotics. MRSA colonisation in pigs was first reported from the Netherlands in 2005, where pigs were implicated as a source of human MRSA infections (Voss et al., 2005). This paper presents the first report on the presence of MRSA on large pig breeding farms in Croatia, together with the determination of the mecA gene, the results of spa typing and susceptibility to commonly used antimicrobials. Dust samples (7-11 per farm) were collected from eight large pig farms in Croatia. Of the total 68 swabs, the mecA gene was detected in 24 isolates growing on the MRSA agar. All isolates were resistant to oxacillin, tetracycline and streptomycin, and susceptible only to vancomycin, while 92% of the strains were susceptible to ciprofloxacin. Genotyping of the MRSA strains was performed by spa typing, and revealed t011 (n = 17), t034 (n = 5) and t1451 (n = 2). The results presented here predict that MRSA is present on a large number of pig farms in Croatia.