| Campylobacter is an important zoonotic disease which can cause diarrhea,enterocolitis,miscarriage and fetal death in humans.Many studies demonstrated that Campylobacter infection is associated with a neurological disease,Guillain-Barre syndrome.Ca,mpylobacter is commonly found in the gastral intestinal track of animals,such as chicken,duck and goose,which makes avians as important sources of Campylobacter infections.In addition,several studies have also detected Campylobacter in primates.Monkeys have the similar body structures,genetic structures and living habits as humans.In non-human primate-based farming and research,Campylobacter infection can cause several problems,such as affecting the experiment,affecting the growth and reproduction of non-human primates,endangering the public environment,and infecting personnel with direct contact to the animals,etc.Therefore,it is important to reduce Ca.mpylobacter infections in non-human primates and avoid cross contamination.In addition,it is also essential to prevent Campylobacter transmission between humans and animals.This project is aimed:(1)to investigate the distribution and prevalence of Campylobacter in non-human primates and its living environment;(2)to explore the prevalence and persistance of Campylobacter in newborn monkeys;(3)to explore the epidemiology,biological characteristics and antibiotic resistance of Campylobacter isolates.1.Prevalence of Campylobacter from different samples and moneys under different raising modelsFrom April 2017 to December 2018,a total of 1668 samples were collected from three different non-human primate farms,including 1275 monkey anal swabs(excluding the number of replicated samples),371 environmental samples and 22 anal swab samples from professionals.A total of 405 Campylobacter isolates were detected,including 82 Campylobacter jejuni isolates,317 Campylobacter coli isolates and 6 other Campylobacter spp isolates.In total,29.2%of anal swab samples were Campylobacter positive.After grouping monkeys by a 4-year(48 months)period,our study showed that Campylobacter infections were significantly decreased while the age of monkeys increased.Based on the gender difference,32.6%of female were infected by Campylobacter,which was significantly higher than that of males(18.6%).In addition,species also had an influence to Campylobacter infection,in which cynomolgus monkeys(35.6%)was significantly higher than that of rhesus monkeys(13.6%).The diarrhea symptoms had only been observed from Farm A,which were analyzed separately.Overall,Campylobacter have been isolated from 61.7%of diarrhea monkeys,while 33.4%of non-diarrheal monkeys were Campylobacter positive.A total of 285 environmental samples were collected from Farm A,which 18 C coli isolates were detected.Campylobacter positive samples were mainly from monkeys,cribs(10.3%),grounds(6.6%)and breeders,soles(30.4%).The treatment of feces in Farm A could have a primary influence to Campylobacter transmission to the environment,which monkey feces fell to the ground from the cages and washed away by water pipes to the sewer.Both the ground and the soles of the staff has a high risk of carrying Campylobacter,indicating that the main transmission of Campylobacter is based on the fecal-oral route.Camparing to the Farm A,Farm B colleted monkeys' urine and excrement by an iron pad containing corn cob particles,which kept the enviromnent dry and clean.In addition,there are two different kinds of raisng methods:keeping monkeys in a small cage separately or a big cage in groups.Farm A kept every rhesus monkeys in a small cage,but kept cynomolgus monkeys by either a separate small cage or in groups and occasionally changed between the two kinds of cages,which increased the opportunities for Campylobacter transmission.Our study shown that that the culture method which makes monkeys could contact with each other and inappropriate treatment of feces disposal would be significant risk factors for Campylobacter circulating among monkeys.2.A tracking investigation of Campylobacter infection in newborn cynomolgus monkeyFrom August 2017 to June 2018,the infection of Campylobacter in 10 newborn monkeys was tracked.It was found that Campylobacter infection occurred only six times in the first 1-10 weeks(6%)including five of C.jejuni isolates and one of C.coli isolates.During 11 to 20 weeks,14 of Campylobacter infection(14%)was detected,which C.jejuni infection occurred 6 times and C.coli infection occurred 8 times.A total of 80 anal swab samples were collected from 21 weeks and later,which 28 of Campylobacter infection(35%)occurred including 10 C.jejuni isolates and 18 C.coli isolates.Campylobacter infection in newborn monkeys occurred more frequently over time during our tracking period.Besides,C.jejuni infection was increasing while C.coli infection was decreasing.MLST analysis have shown that 25 C.coli isolates from newborn monkeys contained 7 of different STs.The dominant STs were ST-3753,ST-828,and novel ST 5 which accounting for 68%(17/25)of C.coli isolates.Five of novel STs were observed from 13 of C.coli isolates.This study indicated Campylobacter could infect newborn monkeys within the first week,and novel STs were frequently found in the newborn monkeys.Based on this,it is speculated whether the physique of the newborn animal is more suitable to change the strain's genes,then produce novel STs.3.Epidemiological study of Campylobacter isolates and its drug resistanceMLST typing of 171 C.coli isolates was earied out and 23 different ST types were obtained,which reflected the high diversity of the genome of C.coli.Predominate ST types are ST-1586.ST-829,ST-3023 and ST-1096.11 of novel STs could not find in the PubMLST database(httvs'J/vxxbmlstora/Campvhbacter),including 38 isolates which accounting for 22.2%of the total isolates.A total of 154 C.coli isolates from anal swab samples were analyzed,the other 17 Campylobacter coli isolates from environmental samples contained 11 STs.Among the monkey anal swab isolates,126 strains were matched with these 11 STs,accounting for 81.8%.In addition,there is no corresponding relationship between the ability of adhesion and invasion of these strains and their STs according to the tests of adhesion and invasion.The antibiotic susceptibility test of 12 antibiotics was conducted to evaluate the antibiotic resistant of Campylobacter isolates including 35 C.jejuni isolates and 79 C.coli isolates.The results showed that both C.jejuni(82.86%)and C.coli(89.87%)were highly resistance to ciprofloxacin.A total of 104 multi-drug resistant strains were present in 114 isolates,containning 43 multi-drug resistant phenotypes.In total,35 C.jejuni isolates were multi-drug resistant,and 40%C jejuni isolates were resistance to two antibiotics.77 multidrug-resistant C.coli strains was present,64.6%of C coli strains were resistant to 4,5 and 6 antibiotics.Among multi-drug resistant C.jejuni strains,the highest number of strains(18.5%)belonged to CIP-LEV(ciprofloxacin-levofloxacin)resistance pattern.Among the 77 multi-drug resistant C.coli,the resistance pattern of CIP-P-LEV-CRO-CTX-S(ciprofloxacin-penicillin-levofloxacin-ceftizoxone-cefotaxime-streptomycin)and CIP-P-E-AZM-LEV(ciprofloxacin-penicillin-erythromycin-azithromycin-levofloxacin)were most frequently observed,which accounted for 13.0%and 10.4%of the total C.coli strains,respectively.Compared to C.jejuni isolates,the occurrence of multi-drug resistance in C.coli isolates was more frequently.Among the 12 antibiotics,more than 80%Campylobacter isolates were sensitive to gentamicin,amoxicillin.These 2 antibioties are suitable for the farm to treat Campylobacter infections. |
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