Mycoplasma agalactiae ST35: a new sequence type with a minimal accessory genome primarily affecting goats

Background

Mycoplasma agalactiae, causing agent of contagious agalactia, infects domestic small ruminants such as sheep and goats but also wild Caprinae. M. agalactiae is highly contagious and transmitted through oral, respiratory, and mammary routes spreading rapidly in an infected herd.

Results

In an outbreak of contagious agalactia in a mixed herd of sheep and goats, 80% of the goats were affected displaying swollen udders and loss of milk production but no other symptom such as kerato-conjunctivitis, arthritis or pulmonary distress commonly associated to contagious agalactia. Surprisingly, none of the sheep grazing on a common pasture and belonging to the same farm as the goats were affected. Whole genome sequencing and analysis of M. agalactiae strain GrTh01 isolated from the outbreak, revealed a previously unknown sequence type, ST35, and a particularly small, genome size of 841′635 bp when compared to others available in public databases. Overall, GrTh01 displayed a reduced accessory genome, with repertoires of gene families encoding variable surface proteins involved in host-adhesion and variable antigenicity being scaled down. GrTh01 was also deprived of Integrative Conjugative Element or prophage, and had a single IS element, suggesting that GrTh01 has a limited capacity to adapt and evolve.

Conclusions

The lack of most of the variable antigens and the Integrative Conjugative Element, both major virulence- and host specificity factors of a M. agalactiae strain isolated from an outbreak affecting particularly goats, indicates the implication of these factors in host specificity. Whole genome sequencing and full assembly of bacterial pathogens provides a most valuable tool for epidemiological and virulence studies of M. agalactiae without experimental infections.

Molecular evidence of Anaplasma phagocytophilumin aborted goat fetuses and placenta

Anaplasma phagocytophilum, transmitted by Ixodes ticks, is an intracellular pathogen of zoonotic interest. Regarding animals of veterinary importance, infection by this agent has been linked mainly to high fever, neutropenia, reduced milk production, but hemorrhagic diathesis, abortion and impaired spermatogenesis have also sporadically been reported. In Greece, A. phagocytophilum has been detected in dogs, ticks and humans, while so far only A. ovis had been detected in farm animals. Following the occurrence of multiple abortions in two goat farms in Northern Greece, samples were collected from aborted animals. Stomach contents and placental tissue from aborted animals tested positive for A. phagocytophilum by molecular assays and negative for other infectious and parasitic agents. Treatment with oxytetracycline LA stopped the abortions. In tick risk areas clinicians should consider A. phagocytophilum as a cause of abortion in goats.

Contagious agalactia: costs and control revisited

The economic costs of contagious agalactia (CA) to the small ruminant dairy industry are not well known but include losses due to mortality, lowered milk production, spoiled products, abortions and animal welfare problems, as well as diagnosis and treatment. This paper reports financial estimates made in southern Europe, including a study on small- and large-scale farming systems in Italy, indicating that the financial losses are high and underestimated. Furthermore, the current control strategies, including chemotherapy and vaccination, in selected countries in Europe are described. In some countries, disease control is hampered by excessively strict veterinary legislation which discourages farmers and private veterinarians from notifying outbreaks because it leads to the prohibition of milk sales and can result in delays in lifting restrictions. In addition, new European Union legislation may downgrade the importance of CA, which will have implications for international research efforts. Finally, a series of recommendations are provided that cover the proper notification and handling of CA outbreaks, including movement control, current diagnostics, treatment, vaccination and disinfection.

Isolation and characterization of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) from milk of dairy goats under low-input farm management in Greece

The presence of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in raw milk is a challenge for veterinarians and public health professionals. In this study, we investigated the presence and clonality of S. aureus and MRSA in milk of individual dairy goats with subclinical mastitis reared under the low-input farming system in Greece and determined the isolates' enterotoxin gene carriage and their ability to form biofilms. S. aureus was isolated from 162 out of the 559 milk samples examined (29 %) and one isolate per S. aureus-positive sample was further characterized. S. aureus isolates were very closely related even among farms of distant geographical regions. Nine S. aureus isolates carried a functional mecA gene and were classified as MRSA. The S. aureus protein A (spa) typing in the MRSA isolates showed that four belonged to spa type t127 (44.4 %), three to t2049 (33.3 %) and two to t7947 (22.2 %). The spa type t7947 is reported for the first time in Greece. The MRSA isolates originated from two very distantly located farms, one located in the island of Skopelos and the other in Central Macedonia. Four of the MRSA isolates carried the staphylococcal enterotoxin genes sea or sec. Most of the isolates (92 % of S. aureus and 77.8 % of the MRSA) possessed moderate or weak biofilm-formation ability. Raw milk from low-input goat herds may serve as a potential vector of antimicrobial-resistant S. aureus to raw-milk consumers.

Short communication: Bovine mastitis caused by a multidrug-resistant, mcr-1-positive (colistin-resistant), extended-spectrum β-lactamase-producing Escherichia coli clone on a Greek dairy farm

We performed a survey aimed at analyzing milk samples collected from cows with mastitis for the presence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. Single-quarter mastitic milk samples obtained from 400 cows in 23 Greek dairy herds with a history of E. coli mastitis were processed for the selective isolation of ESBL-producing E. coli. The antimicrobial susceptibility of the ESBL-producing isolates was analyzed using agar disk diffusion, and minimum inhibitory concentrations of colistin were determined by broth microdilution. We used PCR followed by DNA sequencing to characterize the β-lactamases and mcr-1 (colistin resistance) genes, and for phylotyping and multilocus sequence typing. We found a total of 89/400 (22.25%) E. coli isolates from 12/23 (52%) farms. Six isolates originating from 6 cows on a single farm were ESBL producers and were resistant to cefquinome, amoxicillin-clavulanic acid, aztreonam, ampicillin, and colistin. Five of these isolates were resistant to trimethoprim-sulfamethoxazole, and 5 to streptomycin. The 6 ESBL producers were mcr-1-positive and carried bla_TEM-1 genes; 3 also carried bla_CTX-M genes, and 3 carried bla_SHV genes. All of the ESBL producers belonged to phylogroup A, multilocus sequence type ST666 (n = 5), or a single locus variant of ST666 (n = 1). To our knowledge, this is the first report of endemic bovine mastitis caused by mcr-1-positive, ESBL-producing E. coli. These results highlight the value of active surveillance of antimicrobial resistance not commonly tested by diagnostic laboratories for the early detection of novel resistant strains.

Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in bulk tank milk, livestock and dairy-farm personnel in north-central and north-eastern Greece: Prevalence, characterization and genetic relatedness

Recently, there has been an increased tendency towards raw-milk consumption, which may pose a consumer risk, due to the possible presence of human pathogenic microorganisms, such as Staphylococcus aureus and even methicillin-resistant S. aureus (MRSA). The prevalence of S. aureus and methicillin-resistant S. aureus (MRSA) was investigated in 40 dairy (cattle, sheep and goat) farms in northern Greece. S. aureus and MRSA were detected in 47.8% and 4.1% of the 387 samples (raw milk, farmers and animal samples) tested, respectively. Most (81.3%) of the MRSA isolates harbored the mecA gene, whereas the mecC or Panton-Valentine Leucocidin (PVL) genes were not detected. Seven spa types were identified, with t127 being the most prevalent. Spa type t034 (CC398) was isolated for the first time from livestock in Greece. Staphylococcal enterotoxin genes were detected in 93.8% of the MRSA isolates. The MRSA isolates were genetically diverse and were all capable of biofilm production. Our results confirm the lurking threat of MRSA in raw milk and dairy farms and suggest the need for surveillance programs starting at the farm level.

Hemorrhagic pneumonia in neonatal minks in Greece concomitant with Leismania infantum detection

In the present study a severe outbreak of hemorrhagic pneumonia (HP) in neonatal minks concomitant with Leismania infantum (L. infantum) detection is reported. The outbreak took place on a Greek mink farm and affected 1,362 mink kits, with 524 dying. Macroscopic lesions of 14 necropsied affected kits were confined to the respiratory system with dark red, consolidated lung lobes and to the small intestine with severe, acute, hemorrhagic and necrotic enteritis. Microscopic examination of lung sections revealed severe hemorrhagic pyogranulomatous pneumonia. Bacteria were obtained in pure culture from the lungs of all necropsied animals and were confirmed as Pseudomonas aeruginosa (P. aeruginosa). Three out of 14 (21.4%) animals were positive for the presence of L. infantum DNA. The outbreak was attributed to the infection of minks with P. aeruginosa, possibly as a consequence of being immuno-suppressed by L. infantum. Further research is necessary, especially on the pathogenesis of P. aeruginosa/L. infantum co-infection and the implications of this interaction on HP disease outcome.

Fly repellency using deltamethrin may reduce intramammary infections of dairy cows under intensive management

The aim of this study was to assess the possible effect of the fly repellent deltamethrin on the full microbiological profile of the intramammary infections as well as on the somatic cell count in one Greek dairy cattle farm under intensive management, during peak fly season. Fifty five multiparous cows, stabled in the same farm, were randomly divided in three groups; cows of Group A were dressed on their back with deltamethrin, cows of Group B remained untreated within the same pen and cows of Group C remained untreated in a separate pen. Clinical records of the herd showed a history of clinical and subclinical mastitis (especially during spring and early summer) and fly infestation. Deltamethrin reduced fly population, landing on the cows of Group A, facilitating a significant decrease of S. aureus, coagulase negative staplylococci, E. coli intramammary infections and somatic cell count, throughout the study period. Consequently, there is a relationship between fly abundance and transmission of bacteria resulting in intramammary infections and mastitis in dairy cows. The use of the pyrethroid deltamethrin reduced fly abundance and therefore, the possibility of transmitting pathogenic bacteria in the mammary gland.

Serological prevalence of Coxiella burnetii in dairy goats and ewes diagnosed with adverse pregnancy outcomes in Greece

INTRODUCTION

Coxiella burnetii is an obligatory intracellular bacterial pathogen causing the zoonotic disease Q fever. The most common reservoirs of C. burnetii are wild mammals, birds and ticks. Pregnant domestic ruminants infected with this bacterium are also a major source of human infection.

MATERIAL AND METHODS

The serological prevalence of C. burnetii in goats and sheep diagnosed with adverse pregnancy outcomes was assessed by undertaking a survey on 800 dairy goats and 800 dairy ewes reared in four different regions of Greece (Macedonia, Thrace, Thessaly, and Peloponnese). A stratified sampling was carried out, taking also as a criterion the age of the animals. Serum antibodies were analyzed by a commercial ELISA according to the manufacturer's recommendations.

RESULTS

Generally, there was a statistically significantly higher serological prevalence of C. burnetii (14.4%) in goats compared to sheep (8%). Serological prevalence was higher in adults (15.5% in goats and 8.5% in sheep) compared to yearlings (7.4% in goats and 4.6% in sheep). The prevalence increased significantly with age only in goats. Finally, all animals reared in Peloponnese had a prevalence significantly higher (21% in goats and 18% in sheep) than animals reared in the other three regions.

CONCLUSIONS

To the best of the authors' knowledge, this is the first report that associates C. burnetii with reproductive disturbances of domestic ruminants in Greece. However, considering the importance of coxiellosis for public health, further investigations are required on its epidemiology regarding abortion, premature delivery, stillbirth and weak offspring in small ruminants, as well as in other domestic and wild animal species.

Evaluation of the in-field efficacy of oregano essential oil administration on the control of neonatal diarrhea syndrome in calves

The objective of this study was to evaluate under field conditions, whether daily administration of oregano essential oil is effective in preventing and/or diminishing the severity of neonatal diarrhea syndrome in calves aged less than 15days. Ninety-one newborn calves from three dairy farms were assigned into two groups; "Eco" group (n=46) calves were drenched with Greek oregano (Origanum vulgare ssp. Hirtum) essential oil (ECODIAR® liquid 5%) at the dose of 12.5mg/kg body weight once per day until the age of 10days. "Conts" group (n=45) calves were left untreated and served as controls. All animals were monitored daily for the incidence of diarrhea until the age of 15days and their fecal score was recorded. Fecal samples were collected on days 3, 6 and 10 for microbiological and parasitological evaluation. Average fecal score throughout the experiment, incidence of diarrhea, duration and severity of diarrhea episodes were significantly lower in Eco group compared to the controls. Daily administration of oregano essential oil in calves for the first 10days of their life effectively diminishes the severity of naturally acquired diarrhea under field conditions and, under certain hygiene practices, possess a preventive effect against neonatal diarrhea syndrome.

Bacterial subclinical mastitis and its effect on milk yield in low-input dairy goat herds

The objectives of this study were (1) to record the major pathogens associated with subclinical mastitis (SCM), (2) to calculate their incidence during the milking period, and (3) to estimate the effect of SCM on daily milk yield (DMY) for goats reared under low-input management schemes. Dairy goats (n=590) of Skopelos and indigenous Greek breeds from 4 herds were randomly selected for the study. The study included monthly monitoring, milk yield recording, and bacteriological analyses of milk of individual goats during the course of 2 successive milking periods. Incidence and cumulative incidence were calculated for SCM cases. Moreover, 2 mixed linear regression models were built to assess the effects of (1) SCM and (2) different pathogens isolated from SCM cases, on DMY. The estimated incidence and cumulative incidence of SCM for the first and the second year of the study were 69.5 and 96.4 new cases of SCM/1,000 goat-months, and 24.1 and 31.7%, respectively. A total of 755 milk samples were subjected to microbiological examination, resulting in 661 positive cultures. Coagulase-negative and coagulase-positive staphylococci were isolated from 50.2 and 34.5% of the positive cultures, respectively. The incidence of infections (new infections per 1,000 goat-months) for the first and the second year of the study were 34 and 53 for coagulase-negative staphylococci, 23 and 28 for coagulase-positive staphylococci, 3 and 5 for Streptococcus/Enterococcus spp., and 5.5 and 9.1 for gram-negative bacteria. Goats with SCM had lower DMY when compared with goats without SCM (ca. 47g/d, corresponding to a 5.7% decrease in DMY). In particular, goats with SCM due to coagulase-positive staphylococci infection produced approximately 80g/d less milk (a reduction of ca. 9.7%) compared with uninfected ones, whereas SCM due to gram-negative bacteria resulted in approximately 15% reduction in DMY. Investigating the epidemiology of SCM and its effects on production traits is critical for the establishment of effective preventive measures against SCM and for the assessment of the sustainability of production in low-input dairy goat herds.

Reproductive performance of sows was improved by administration of a sporing bacillary probiotic (Bacillus subtilis C-3102)

This field study assessed the efficacy of a probiotic based on viable spores of Bacillus subtilis C-3102 (Calsporin; Calpis Co. Ltd., Japan) on the health status and productivity of sows and their litters through 2 full, sequential reproductive cycles from service of the first cycle to weaning of the second cycle. Fifty-six sows were allocated to 2 experimental groups, an untreated control (T1) group and a probiotic-treated (T2) group that received the same basal feed as the T1 group plus the probiotic at an approximate allowance of 30 g/t of feed (3 × 10(5) cfu/g). The offspring of T1 and T2 sows were offered basal and T2 creep feed (3 × 10(5) cfu/g), respectively. Health and zootechnical parameters of sows and piglets were recorded. Feeding the probiotic to sows and piglets resulted in significant benefits, observed in both cycles: 1) improved sow body condition during pregnancy (P < 0.05), 2) increased sow feed consumption, 3) reduced sow weight loss during lactation (P < 0.05), 4) reduced sow weaning-estrus interval (P < 0.05), and 5) higher BW of piglets at weaning (P < 0.05). Additionally, a significant (P < 0.05) improvement in piglet birth weight and in the number of piglets weaned was observed in the second cycle of T2 sows, while a significant improvement of mean daily gain of piglets from birth to weaning was observed in the first cycle of T2 sows. Microbiological examination of fecal samples showed that probiotic treatment significantly reduced both Escherichia coli and Clostridium spp. in piglet feces, particularly during the second cycle. The data suggested that continuous feed supplementation with the probiotic is beneficial for both sows and piglets, since zootechnical benefits were observed in both cycles.

In vitro susceptibilities of caprine Mycoplasma agalactiae field isolates to six antimicrobial agents using the E test methodology

The minimum inhibitory concentrations (MICs) of enrofloxacin, ciprofloxacin, spectinomycin, tetracycline, spiramycin and erythromycin against 30 caprine Greek isolates of Mycoplasma agalactiae were determined using E test methodology. The E test strips were placed on Eaton's agar medium without antimicrobials and phenol red. MICs were then read by determining where the growth inhibition zone intersected with the MIC scale on the strip. An MIC value of 8 µg/mL was considered as a guide to mycoplasma resistance. All isolates were sensitive to fluoroquinolones (MIC50, 0.19 g/mL; MIC90, 0.38 µg/mL; highest MIC, 0.5 µg/mL), spectinomycin (MIC50, 0.5 µg/mL; MIC90, 1 µg/mL; highest MIC, 1 µg/mL), and spiramycin (MIC50, 1 µg/mL; MIC90, 1.5 µg/mL; highest MIC, 2 µg/mL). Two strains exhibited resistance to tetracycline (MIC 32 µg/mL) but these were not found to carry any of the tet(M), tet(O), and tet(S) resistance genes. Finally all isolates expressed resistance to erythromycin (MIC50, 128 µg/mL; MIC90, >256 µg/mL).

An outbreak of caprine meningoencephalitis due to Escherichia coli O157:H7

Five 1-month-old kid goats from a local herd in Kozani (northwest Greece) developed neurological disorders characterized by decreased appetite, ataxia, and head pressing. The animals received a 3-day course of treatment with intramuscular administration of enrofloxacin and ketoprofen. However, no significant clinical improvement was achieved, and 2 kids died. The remaining 3 animals were euthanized, and a necropsy was performed within 1 hr. Macroscopic lesions were confined to the central nervous system, with congestion and petechiae in the meninges. Microscopic lesions in all 3 animals revealed multifocal acute meningoencephalitis characterized by infiltrations composed of mononuclear inflammatory cells, lesser numbers of lymphocytes, and occasionally neutrophils and eosinophils. Additionally, in the kidney, there was multifocal expansion of the glomerular tufts by eosinophilic amorphous material, multifocal interstitial hemorrhages, and multifocal glomerular hypercellularity. The above noted lesions are consisted with an acute ongoing nephropathy indicative of a septicemic-toxemic procedure at its primary stages. Small, gray bacterial colonies, 3-4 mm in diameter, were obtained in pure culture from the brain of all 3 necropsied animals and were confirmed as Escherichia coli O157:H7 by use of phenotypic and genotypic methods. The isolates were sensitive to cefuroxime, ceftazidime, and gentamicin. In contrast, resistance to enrofloxacin, trimethoprim-sulfamethoxazole, and tetracycline was displayed. Additionally the bacterial isolates were found to carry a plasmid that harbored qnrS, sulII, and tetB genes that contribute to high-level resistance to fluoroquinolones, co-trimoxazole, and tetracycline, respectively.

Isolation and analysis of tetracycline-resistant Mycoplasma agalactiae strains from an infected goat herd in Cyprus - short communication

A major concern with the use of tetracycline against mycoplasmas is the development of resistance. Infections in small ruminants due to tetracyclineresistant Mycoplasma agalactiae strains are becoming a frequent problem worldwide. In the present paper the detection and analysis of three tetracycline-resistant M. agalactiae strains, isolated from infected goats in Cyprus, are reported. The three field isolates were identified as M. agalactiae by polymerase chain reaction (PCR) showing 98% identity to the M. agalactiae PG2 reference strain. Furthermore, they were found sensitive to tylosin, enrofloxacin, spiramycin and lincomycin. In contrast, they were resistant to tetracycline. None of the putative genes [tet(M), tet(O) and tet(S)] that commonly contribute to high-level resistance to tetracycline could be amplified from their genome. Contrarily, the field isolates were found to carry ISMag1, an insertion sequence related to the IS30 family of mobile elements. Although ISMag1 is widely believed to induce high-frequency chromosomal rearrangements resulting in phenotypic changes of microorganisms, its potential role in tetracycline resistance of mycoplasmas requires further studies.

Ciprofloxacin-resistant Escherichia coli isolated from the intestinal microbiota of goats in Greece in the absence of selective pressure

The presence of ciprofloxacin resistance commensal Escherichia coli (C-R-Ec) was determined for goats in the absence of selective pressure in Northern and Central Greece. The C-R-Ec was categorized in 3 groups with respect to their phenotypic resistance to other antibiotics as well as the carriage of antibiotic resistance genes. The first group consisted of 7 C-R-Ec that were found also resistant to tetracycline. Among them tet(B) (n = 7), qnr(S) (n = 7), and qnr(B) (n = 3) producers were identified by polymerase chain reaction. The second group consisted of 10 C-R-Ec that were found sensitive to all other antibiotics, and their phenotypic resistance to ciprofloxacin was not attributed to the presence of resistance genes. Finally, the third group consisted of 2 C-R-Ec also resistant to sulfamethoxazole. These strains were not carrying any transferable elements that contribute to resistance either to ciprofloxacin or to sulfamethoxazole. This is the first report of ciprofloxacin-resistant E. coli isolated from goats in Greece.

Clinical, microbiological and histological findings in lambs affected by 'salivary abomasum disease'

'Salivary abomasum disease' is a common syndrome in Greece affecting lambs and kids from three to 17 days of age. In this case series, we present clinical and laboratory findings from 37 affected lambs presented alive and subsequently euthanased for welfare reasons and necropsied, and also from 24 other lambs submitted dead that were also necropsied. The clinical signs in the 37 lambs presented alive included lethargy (100 per cent), absence of sucking (83.8 per cent), weakness (37.8 per cent), abdominal distension (40.5 per cent) and increased frequency of urination (24.3 per cent). Diarrhoea was not observed in any affected lambs. At necropsy of these 37 lambs, the abomasum was distended with gas (70.3 per cent), saliva (43.2 per cent) along with mixed milk clots and gastric secretions; while multiple small mucosal and serosal haemorrhages with blood clots ('coffee grains') were recorded (91.9 per cent). Eight of 37 lambs that were examined alive, had elevated blood urea nitrogen concentrations (21.6 per cent). The pH of the abomasal contents ranged from 1.0 to 2.8; Escherichia coli was cultured from six of 37 (16.2 per cent) abomasal fluid samples. A mild to moderate inflammatory cell infiltrate was present in the mucosal lamina propria of 13 of 15 abomasal samples (86.6 per cent). Kidneys were paler than normal in 13 of the total 61 lambs necropsied (21.3 per cent); while acute tubular necrosis was evident on histopathological examination of 11 of 12 examined pale kidneys (91.6 per cent). The low abomasal pH and reported successful treatment with oral sodium bicarbonate suggest that metabolic acidosis may develop during the disease; however, further studies, including blood gas analysis, and determination of D- and L-lactic acid concentrations, are necessary to confirm this hypothesis.

Stenotrophomonas Maltophilia as a Causal Agent of Pyogranulomatous Hepatitis in a Buffalo (Bubalus Bubalis)

A 7-year-old female buffalo ( Bubalus bubalis) from a local herd in Serres, northern Greece, was presented to a private veterinary clinic with a chronic loss of appetite for 15 days. The clinical examination revealed high fever (41.5°C), lethargy, yellow discoloration of skin and mucous membranes, an abdomen that appeared to be empty, hyperactive rumen motility, and tachypnea. A biochemical profile revealed an elevated total bilirubin concentration and hepatic enzyme activities, whereas globulin, creatinine, and glucose concentrations were within the reference intervals. The animal received a 12-day course of treatment with intramuscular administration of ampicillin and corticosteroids. However, no significant clinical improvement was achieved, and the buffalo was euthanized. Gross necropsy lesions included serous atrophy of adipose tissue and hepatomegaly. Microscopic lesions included necrotizing pyogranulomatous hepatitis with thrombosis, hemorrhages, edema, and fibrosis. Small, nonpigmented, bacterial colonies were harvested in pure culture from the liver and were confirmed as Stenotrophomonas maltophilia by polymerase chain reaction. The bacterium was sensitive to ciprofloxacin, enrofloxacin, colistin, polymyxin, trimethoprim/sulfamethaxazole, and chloramphenicol. In contrast, resistance to ticarcillin, piperacillin, imipenem, ceftazidime, amikacin, gentamicin, tobramycin, and tetracycline was displayed. The bacterial strain carried the L1 metallo-β-lactamase (L1) and tet35 genes, which contribute to high-level resistance to β-lactams and tetracycline, respectively. Although S. maltophilia is widely believed to be a contaminant, the present report suggests that the isolation, identification, and susceptibility testing of this multidrug-resistant bacterium may be of clinical importance in diagnostic samples.

Stenotrophomonas maltophilia isolated from the airways of animals with chronic respiratory disease

Stenotrophomonas maltophilia (S. maltophilia) is a nonfermentative bacterium, which is naturally resistant against a panel of commonly-used antibiotics. It is frequently isolated from humans with chronic respiratory disease, e.g. cystic fibrosis or chronic obstructive pulmonary disease. In veterinary medicine S. maltophilia is perceived to be a mere coloniser. We herewith report 7 strains of S. maltophilia isolated from animals, of which 5 strains were harvested from 3 horses, a dog and a cat with chronic respiratory disease. The dog isolate showed resistance to trimethoprim / sulphamethoxazole, which was confirmed by detection of the sul 1 gene. Analysis with pulsed field gel electrophoresis revealed that 2 horses, which were boarded in the same clinic but two years apart, harboured the same strain of S. maltophilia. This is indicative of a hospital acquired colonisation / infection, which contradicts involvement in the pre-existing chronic disease.

Microbiological quality of indoor and outdoor swimming pools in Greece: investigation of the antibiotic resistance of the bacterial isolates

During 1997-2005, the microbiological quality and susceptibility of bacterial isolates of swimming pool waters were investigated. A total of 462 water samples were collected from three indoor swimming pools (a teaching pool, a competition public pool, a hydrotherapy pool) and two outdoor swimming pools (a hotel semi-public and a residential private pool) in Northwestern Greece. All water samples were analyzed for the presence of bacteria, protozoa and fungi and susceptibility tests were performed for the bacterial isolates. Sixty-seven percent of the examined water samples conformed to the microbiological standards and 32.9% exceeded at least one of the indicated limits. Out of 107 bacterial isolates, 38 (35.5%) resistant strains were detected. Multi-resistant Pseudomonas alcaligenes, Leuconostoc, and Staphylococcus aureus (isolated from the teaching pool), Staphylococcus wernerii, Chryseobacterium indologenes and Ochrobactrum anthropi (isolated from the competition pool), Pseudomonas aeruginosa, P. fluorescens, Aeromonas hydrophila, Enterobacter cloacae, Klebsiella pneumoniae and S. aureus (isolated from the hydrotherapy pool) and A. hydrophila (isolated from the hotel pool) were detected. The swimming pool with the poorest microbiological quality (THC 500 cfu/ml in 12.1% of the samples, P. aeruginosa counts 1500 cfu/100 ml in 6% of the samples) and the highest prevalence of multi-resistant isolates (73.6%) was the hydrotherapy pool. No Cryptosporidium or Giardia cysts and no Legionella, Mycobacteria and Salmonella were detected, but there were isolations of Candida albicans, Aspergillus spp., Mucor spp., Alternaria spp., Rhizopus spp., Trichophyton spp., and Penicillium spp.

High efficiency electrotransformation of Lactococcus lactis spp. lactis cells pretreated with lithium acetate and dithiothreitol

BACKGROUND

A goal for the food industry has always been to improve strains of Lactococcus lactis and stabilize beneficial traits. Genetic engineering is used extensively for manipulating this lactic acid bacterium, while electropolation is the most widely used technique for introducing foreign DNA into cells. The efficiency of electrotransformation depends on the level of electropermealization and pretreatment with chemicals which alter cell wall permeability, resulting in improved transformation efficiencies is rather common practice in bacteria as in yeasts and fungi. In the present study, treatment with lithium acetate (LiAc) and dithiothreitol (DTT) in various combinations was applied to L. lactis spp. lactis cells of the early-log phase prior to electroporation with plasmid pTRKH3 (a 7.8 kb shuttle vector, suitable for cloning into L. lactis). Two strains of L. lactis spp. lactis were used, L. lactis spp. lactis LM0230 and ATCC 11454. To the best of our knowledge these agents have never been used before with L. lactis or other bacteria.

RESULTS

Electrotransformation efficiencies of up to 105 transformants per mug DNA have been reported in the literature for L. lactis spp.lactis LM0230. We report here that treatment with LiAc and DDT before electroporation increased transformation efficiency to 225 +/- 52.5 x 107 transformants per mug DNA, while with untreated cells or treated with LiAc alone transformation efficiency approximated 1.2 +/- 0.5 x 105 transformants per mug DNA. Results of the same trend were obtained with L. lactis ATCC 11454, although transformation efficiency of this strain was significantly lower. No difference was found in the survival rate of pretreated cells after electroporation. Transformation efficiency was found to vary directly with cell density and that of 1010 cells/ml resulted in the highest efficiencies. Following electrotransformation of pretreated cells with LiAc and DDT, pTRKH3 stability was examined. Both host-vector systems proved to be reproducible and highly efficient.

CONCLUSION

This investigation sought to improve still further transformation efficiencies and to provide a reliable high efficiency transformation system for L. lactis spp. lactis. The applied methodology, tested in two well-known strains, allows the production of large numbers of transformants and the construction of large recombinant libraries.

Diarrheic shellfish poisoning due to toxic mussel consumption: The first recorded outbreak in Greece

During the week of 14-20 January 2000, 120 people visited the Emergency Departments of hospitals in Thessaloniki, northern Greece, complaining of acute gastrointestinal illness after eating mussels (Mytilus galloprovincialis). The symptoms indicated diarrhoeic shellfish poisoning, and the toxicity of mussels harvested from Thermaikos Gulf in Thessaloniki during the outbreak was investigated using mouse bioassays. The bioassays revealed toxicity to mice by the mussel samples; while high numbers of toxic algae Dinophysis acuminata were identified in water samples from Thermaikos Gulf. The harvesting of mussels was immediately suspended and a monitoring programme for algal blooms was established from then onwards. During a follow-up of the mussels' toxicity from January 2000 to January 2005, two more mussel samples were found positive for diarrheic shellfish poisoning: one harvested in March 2001 from the area of the outbreak (Thermaikos Gulf) and the other harvested in January 2001 from Amvrakikos Gulf in north-western Greece. However, no sporadic cases or outbreaks were reported during this period.

Isolation of Mycoplasma bovis from bovine clinical mastitis cases in Northern Greece

Mycoplasma bovis was detected in 18/219 (8.2%) quarter milk samples collected from cases of bovine clinical mastitis in Northern Greece between November 1997 and March 1999. The cases occurred in 2/37 (5.4%) of the herds examined. The micro-organism was isolated from bulk milk samples (BTS) from the two positive herds but was not isolated from 111 composite milk samples collected from clinically healthy cows from all 37 herds. Isolates were identified as M. bovis by polymerase chain reaction (PCR) assay. Other micro-organisms were also isolated from the M. bovis positive samples. The M. bovis-positive cows had all been imported into Greece from other European countries.

Determination of bacteriocin activity with bioassays carried out on solid and liquid substrates: assessing the factor "indicator microorganism"

BACKGROUND

Successful application of growth inhibition techniques for quantitative determination of bacteriocins relies on the sensitivity of the applied indicator microorganism to the bacteriocin to which is exposed. However, information on indicator microorganisms' performance and comparisons in bacteriocin determination with bioassays is almost non-existing in the literature. The aim of the present work was to evaluate the parameter "indicator microorganism" in bioassays carried out on solid -agar diffusion assay- and liquid -turbidometric assay- substrates, applied in the quantification of the most studied bacteriocin nisin.

RESULTS

The performance of characterized microorganisms of known sources, belonging to the genera of Lactobacillus, Pediococcus, Micrococcus and Leuconostoc, has been assessed in this work in the assays of plate agar diffusion and turbidometry. Dose responses and sensitivities were examined and compared over a range of assay variables in standard bacteriocin solutions, fermentation broth filtrates and processed food samples. Measurements on inhibition zones produced on agar plates were made by means of digital image analysis. The data produced were analyzed statistically using the ANOVA technique and pairwise comparisons tests. Sensitivity limits and linearity of responses to bacteriocin varied significantly among different test-microorganisms in both applied methods, the lower sensitivity limits depending on both the test-microorganism and the applied method. In both methods, however, only two of the nine tested microorganisms (Lactobacillus curvatus ATCC 51436 and Pediococcus acidilactici ATCC 25740) were sensitive to very low concentrations of the bacteriocin and produced a linear-type of response in all kinds of samples used in this work. In all cases, very low bacteriocin concentrations, e.g. 1 IU/ml nisin, were more accurately determined in the turbidometric assay.

CONCLUSION

The present work shows that in growth inhibition techniques used in bacteriocin quantification, the choice of the indicator microorganism is critical. Evaluation of sensitivity levels and type of produced responses showed that they can vary widely among different test-microorganisms and different applied methods, indicating that not all microorganisms can be used successfully as indicators and that measurements of growth inhibition in liquid media produce more reliable results.

Isolation of a rare Escherichia coli O157:H7 strain from farm animals in Greece

A strain of Escherichia coli O157:H7 was isolated from goat faeces during a surveillance study on the prevalence of this serotype of E. coli in farm animals in Greece. Three hundred and fifty one faecal samples were collected from goat, sheep and cattle breeding farms in the area of Epirus, Northwestern Greece. The E. coli O157:H7 isolate was nonsorbitol-fermenter, produced only VT2 and showed a beta-glucuronidase positive activity, a rather unusual biochemical feature for the E. coli O157:H7 serotype. No other strain of E. coli O157:H7 was isolated from the faecal samples of the rest farm animals examined, thus the overall prevalence of animal carriage was found to be 0.2%. The findings also indicate that goats can be a reservoir of E. coli O157:H7 and goat milk, dairy products and meat may serve as a vehicle for the pathogen transmission to humans.

Isolation of Escherichia coli O157:H7 from foods in Greece

The presence of Escherichia coli O157:H7 in various foods of animal origin was surveyed in northwestern Greece. Six hundred samples of unpasteurized cows', ewes' and goats' milk, raw minced meat, uncooked frozen beef hamburgers, sandwiches (containing ham or turkey, mixed vegetable salad with mayonnaise and lettuce), fresh traditional Greek pork sausages and swine intestines appropriate for traditional Greek kokoretsi were assayed for E. coli serogroup O157:H7 using the standard cultural method and the immunomagnetic separation technique. The pathogen was detected in 1 out of 100 (1.0%) samples of ewes' milk, 1 out of 75 (1.3%) fresh sausages and 1 out of 50 (2.0%) swine intestines prepared for kokoretsi. The isolated strains were nonsorbitol fermenters, MUG-negative, O157 agglutinating, verotoxin-producing and carried both VT1 and VT2 genes. The three isolated strains were tested for antibiotic resistance and were found to be susceptible to eight antimicrobial agents (ampicillin, chloramphenicol, kanamycin, nalidixic acid, norfloxacin, streptomycin, sulfamethoxazole-trimethoprim and tetracycline).