Detection certainty of the contamination of bull sperm with mycoplasma

Tests for presence of mycoplasmas were conducted on 20 insemination bulls known as mycoplasma spreaders, with 5 sperm pellet batches of 20 pellets each being investigated for each animal. Mycoplasma contamination was positively recorded from 83 of the above 100 batches. Mycoplasma (M.) bovigenitalium, M. californicum. M. arginini, M. bovirhinis, and Acholeplasma laidlawii were typed by means of indirect immunofluorescent technique, which confirmed the presence also in the GDR of mycoplasma species described in the literature and detected in sperm samples. The solid culturing media used in the above tests, medium-B agar and cattle blood agar with staphylococcal nutrix, proved to be equally suitable for isolation of mycoplasma from sperm samples. Mycoplasma was positively identified in about one third of all pellets/batches tested. 3 pellets to one batch should be sufficient a random sample size from which to obtain information at least very close to real contamination.     

In vitro antibiotic susceptibility of Mycoplasma iguanae proposed sp. nov. isolated from vertebral lesions of green iguanas (Iguana iguana).

Mycoplasma iguanae proposed species nova was isolated from vertebral abscesses of two feral iguanas (Iguana iguana) from Florida. Three strains were evaluated for sensitivity to a variety of antibiotics. The minimum inhibitory concentrations for M. iguanae, assessed by broth dilution methods, of clindamycin, doxycycline, enrofloxacin, oxytetracycline, and tylosin (all <1 microg/ml) were lower than those of chloramphenicol (32 micro/ml) and erythromycin (64 microg/ml). The profile was identical to that of Mycoplasma alligatoris, previously isolated from American alligators (Alligator mississippiensis). M. iguanae strain 2327T was subcultured without antibiotics to assess mycoplasmacidal activity. Clindamycin, doxycycline, oxytetracycline, and tylosin were bacteriostatic from 0.1 to 0.5 microg/ml, whereas enrofloxacin was bactericidal at 20 ng/ml. An enrofloxacin dosage of 5-10 mg/kg achieves peak plasma concentrations >1 microg/ml, with an elimination half-life of 6-20 hr, in alligators. Although concentrations achieved in the vertebrae by i.m. or i.v. injection are probably lower than those in plasma, these data suggest that enrofloxacin may be useful to treat M. iguanae mycoplasmosis in iguanas.     

Detection of Mycoplasma hominis and Ureaplasma urealyticum in patients with leukospermia

Cytological and microbiological tests were applied to urethral and prostate secretion, initial, midstream, and postmassage urine, and ejaculate of 61 patients with granulocyte counts of approximately 2 million/ml sperm, using the working principle of four-tube testing. Findings included 8 cases of chronic urethritis (caused by Chlamydia trachomatis in 5 instances, Ureaplasma (U.) urealyticum in 2, and Mycoplasma (M.) hominis in 1), 11 cases of chronic bacterial prostatitis, most of them in concomitance with urinary tract infections, and another 11 cases of "abacterial" prostatitis caused by mycoplasma (U. urealyticum in 10 cases, M. hominis in 1). No pathogens at all were recordable from 31 patients, among these 22 without leucocyte proliferation in urethral and prostate secretion nor in urine sediments. While no positive cytological findings were recordable from controls, significant germ counts of U. urealyticum were exhibited by 4 probands. The above findings are discussed together with their problematic interpretation.     

Detection of mycoplasmas in experimentally-infected bull sperm

Bull sperm pellets experimentally infected with various concentrations of Mycoplasma (M.) bovis, M. bovigenitalium, and M. californicum were stored several months at -196 degrees C and were subsequently tested for mycoplasmas, using different methods and culturing media. M. bovis was reliably identified by laboratory diagnosis up to a concentration of 10(2) cfu/pellet. M. bovigenitalium and M. californicum were found to make higher demands on the quality of culturing substrates. Recommended are 1-h broth incubation and 5-d broth breeding.     

The frequency of detection of Mycoplasma meleagridis in breeding turkeys depending on the laying age

Coating of air sacs was recorded from day-old chicks from parents with Mycoplasma (M.) meleagridis infection, with positive findings being obtained from 9.52% of all animals early in the laying period and from 34.09% up to the 8th laying week. M. meleagridis was isolated from palatine and cloacal swabs taken of laying hens and insemination cocks, with positive findings being 50-60% prior to the laying period (28th week of age), 100% at start of laying, and 80% in the 14th laying week. M. meleagridis was identified in 50% of all embryonated eggs as of the 1st laying week and in 100% as of the 4th week. M. meleagridis was cultured from 30.67% of all sperm samples tested, between the 30th and 46th week of production. Differences were found to exist between individual cocks, with 4 cocks being without M. meleagridis at all. There was usually agreement between positive M. meleagridis findings from sperm and cloacal swabs. M. meleagridis was eliminated from cock sperm by spectinomycin (0.6 mg/ml diluting medium), but M. iowae was not.     

Development of a real-time PCR for detection of Mycoplasma bovis in bovine milk and lung samples.

A real-time polymerase chain reaction (PCR) assay using hybridization probes on a LightCycler platform was developed for detection of Mycoplasma bovis from individual bovine mastitis milk and pneumonic lung tissues. The detection limit was 550 colony forming units (cfu)/ml of milk and 650 cfu/25 mg of lung tissue. A panel of bovine Mycoplasma and of other bovine-origin bacteria were tested; only M. bovis strains were positive, with a melting peak of 66.6 degrees C. Mycoplasma agalactiae PG2 was also positive and could be distinguished because it had a melting peak of 63.1 degrees C. In validation testing of clinical samples, the relative sensitivity and specificity were 100% and 99.3% for individual milks and 96.6% and 100% for the lung tissue. Using M. bovis real-time PCR, the M. bovis culture-positive milk samples were estimated to contain between 5 x 10(4) and 7.7 x 10(8) cfu/ml and the M. bovis culture-positive lungs between 1 x 10(3) and 1 x 10(9) cfu/25 mg. Isolation, confirmed with the real-time PCR and colony fluorescent antibody test, showed that at the herd level, the proportion of samples positive for M. bovis isolation in mastitis milk samples submitted to the Mastitis Laboratory, Animal Health Laboratory, University of Guelph, Ontario, Canada, was 2.4% (5/201). We conclude that this probe-based real-time PCR assay is a sensitive, specific, and rapid method to identify M. bovis infection in bovine milk and pneumonic lungs.     

Protease-induced hyperactivation of canine spermatozoa associated with disappearance of lectin-binding glycoproteins on their surface

The relationship between the disappearance of glycoproteins from the surface of canine sperm and sperm capacitation was investigated in vitro. The protease (PR) concentration in flush fluids of the uterine horns and oviducts removed from 6 estrous, 5 diestrous, and 5 anestrous bitches was measured with a protease assay kit. Ejaculated sperm collected from 10 dogs were incubated for 4 hr in Eagle's MEM supplemented with 1 or 5 microg/ml PR, or to which no PR had been added (control). The glycoproteins on the surface of the sperm were stained with 4 different FITC-lectins (Con A, PHA-E, PNA, and WGA), and the percentages of hyperactivated (HA-) sperm and acrosome-reacted (AR-) sperm were evaluated. The mean PR concentration (5.95 microg/ml) in the flush fluid from the oviducts of the estrous bitches was significantly higher than in the fluid from their uterine horns (1.00 microg/ml; P<0.01). The PR concentrations of the flush fluids from the uterine horns and oviducts of both the diestrous and anestrous bitches were less than 0.05 microg/ml. Before incubation the acrosomal regions or entire heads of all sperm clearly stained with each FITC-lectin, but the percentages of sperm binding the 4 FITC-lectins decreased after incubation. The percentages of lectin-binding sperm in the MEM containing 5 microg/ml PR were significantly lower than in the control MEM (P<0.05 and 0.01). The mean percentages of motile sperm and HA-sperm after incubation in the MEM with PR were higher than in the control MEM, but there were no differences in the percentages of AR-sperm. The results indicate that HA-movement of sperm is induced by the disappearance of glycoproteins from the surface of canine sperm as a result of the action of PR in the oviductal fluid of estrous bitches.     

A survey of avian Mycoplasma species for neuraminidase enzymatic activity

Among 23 currently recognized avian Mycoplasma (AM) species only Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma meleagridis and Mycoplasma iowae cause disease and loss of production in chickens and/or turkeys. Because neuraminidases are considered virulence factors in many pathogenic microorganisms the aim of our study was to determine which AM species possess neuraminidase enzymatic activity (NEAC). Small samples of AM cells were assayed for NEAC using the chromogenic substrate 5-bromo-4-chloro-3-indolyl-alpha-d-N-acetylneuraminic acid. In the case of positive NEAC reaction the substrate gave the insoluble indigoblue product what enabled simple test and easy estimation of NEAC. M. gallisepticum and M. synoviae which share sequences of the gene encoding neuraminidase (sialidase NanH) exhibited considerable levels of NEAC. However, NEAC levels differed among their strains, as well as among cultures of different strains. Only certain cultures of the type strain of M. meleagridis showed NEAC, whereas among six serovars of M. iowae only serovar I (type strain 695) showed NEAC. Weak NEAC was detectable in M. anseris, M. cloacale and M. pullorum, whereas the type strain of M. corogypsi (BV1) showed strong NEAC. Our study provides novel informations about NEAC in AM species and suggests that higher invasiveness and possibly, the pathological processes might be associated with their NEAC.     

The effect of Mycoplasma bovis on fertilization processes in vitro with bull spermatozoa and zona-free hamster oocytes

The effect of Mycoplasma bovis (Donetta strain) on the ability of bull spermatozoa to interact with zona pellucida-free hamster oocytes was studied in an in vitro assay. Ejaculates of semen from a fertile Holstein bull were used fresh on the day of collection (unextended semen) as well as diluted with egg yolk-citrate and used the following day (extended semen). The addition of M. bovis to both unextended and extended semen at a mycoplasma to sperm cell ratio of 10:1 significantly reduced sperm penetration rates and the mean number of sperm per penetrated egg. Similarly, the ability of spermatozoa to form pronuclei and the activation of penetrated oocytes were adversely affected by M. bovis. No apparent effect on sperm motility was detected. When M. bovis was added to the oocytes, there was a marked reduction in the sperm penetration rates and fertilization processes suggesting that the organism affects certain oocyte function(s). The results indicate that the presence of M. bovis in semen or in the female reproductive tract may affect fertilization. Moreover, the in vitro assay with hamster oocytes was found to be useful for demonstrating the effects of contaminating microbial agents on bovine fertilization processes.     

Addition of D-penicillamine,hypotaurine, and epinephrine (PHE) mixture to IVF medium maintains motility and longevity of bovine sperm and enhances stable production of blastocysts in vitro

The present study aimed to establish an efficient system for bovine embryo production by in vitro fertilization (IVF) that can achieve stable normal fertilization and blastocyst developmental rates in any bull without optimization of the sperm concentration in IVF medium. We examined the effects of a PHE mixture (20 μM D-penicillamine, 10 μM hypotaurine and 1 μM epinephrine), theophylline (2.5 mM), and sperm concentration (1, 2 or 5 × 10⁶ cells/ml) on fertilization and blastocyst developmental rates. High cleavage rates (78.3 to 92.4%) and blastocyst developmental rates (31.9 to 62.0%) at day 7 were obtained in the presence of PHE and theophylline in IVF medium with a sperm concentration of 2 × 10⁶ cells/ml using sperm from 9 bulls. In addition, the synergistic effect of PHE and theophylline on normal fertilization (2 pronuclei) was clarified at 12 h after IVF with a sperm concentration of 1 × 10⁶ cells/ml. Moreover, high linearity, high flagellar beat cross frequency, and low amplitude of lateral head of motile sperm were found by computer-assisted sperm analysis. In conclusion, the combination of the PHE mixture and theophylline synergistically accelerates sperm motility and sperm penetration of bovine oocytes. Theophylline activates sperm motility with increasing intracellular cAMP. However, PHE prevents an excessive increase of cAMP and maintains sperm motility without hyperactivation. When the combination of PHE and theophylline is added to IVF medium at a sperm concentration of 2 × 10⁶ cells/ml, we can achieve stable normal fertilization and blastocyst development in any bull.     

In vitro susceptibilities to fluoroquinolones in current and archived Mycoplasma gallisepticum and Mycoplasma synoviae isolates from meat-type turkeys

Monitoring of susceptibility to antibiotics in field isolates of pathogenic avian mycoplasmas is important for appropriate choice of treatment. Our study compared in vitro susceptibility to enrofloxacin and difloxacin in recent (2005-2006) isolates of Mycoplasma gallisepticum and Mycoplasma synoviae from meat-type turkey flocks with archived (1997-2003) isolates and reference strains. Comparison of minimal inhibitory concentration (MIC) values determined by microtest, agar dilution and commercial Etest showed good agreement, but underscored the need for standardized methods for testing. Notably, while the commercial Etest was convenient and accurate for determining MICs for enrofloxacin in the range 0.002-0.094mug/ml, the endpoint of inhibition for M. gallisepticum and M. synoviae strains with MIC values >/=1.0mug/ml could not be determined. A decrease in susceptibility to both fluoroquinolones was detected in archived strains but to a greater degree in recent isolates, most of which had MICs above the NCCLS susceptibility breakpoint for these antibiotics (相似文献   

In vitro drug susceptibility pattern of Mycoplasma alligatoris isolated from symptomatic American alligators (Alligator mississippiensis).

A recently described mycoplasma, Mycoplasma alligatoris, was isolated from dead American alligators (Alligator mississippiensis) that had demonstrated clinical signs of lethargy, anorexia, bilateral ocular discharge, edema. paraparesis, and polyarthritis. The in vitro minimum inhibitory concentration for nine antibacterial agents was determined through serial dilution in broth and plate culture for M. alligatoris isolates. The inhibitory concentration obtained for doxycycline, enrofloxacin, sarafloxacin, oxytetracycline, tilmicosin, and tylosin (< 1 microg/ml) was lower than that of clindamycin (1-8 microg/ml), chloramphenicol (8-16 microg/ml), and erythromycin (32-138 microg/ml).     

Efficacy of tulathromycin in the treatment of bovine respiratory disease associated with induced Mycoplasma bovis infections in young dairy calves

The efficacy of tulathromycin in the treatment of bovine respiratory disease (BRD) due to Mycoplasma bovis was determined following experimental infection. Two highly pathogenic strains of M. bovis (with minimum inhibitory concentration values for tulathromycin of 1 and >64 microg/ml) were inoculated into 145 calves. Four days after inoculation, calves with clinical BRD were treated subcutaneously with saline or tulathromycin (2.5 mg/kg). Compared with saline, BRD-related withdrawals, peak rectal temperatures, and lung lesion scores were significantly lower for tulathromycin-treated calves (P < .01). Tulathromycin was highly effective in the treatment of BRD due to M. bovis in calves regardless of the minimum inhibitory concentration of the challenge strain (1 or >64 microg/ml).     

The Effect of Oestradiol, Progesterone and Heparin on Bovine Spermatozoa Function After Thawing

The present experiment was designed to determine the effects of various biologically active substances, such as oestradiol (OE), progesterone (P4) and heparin (Hep) alone or in combination on sperm plasma membrane scrambling, capacitation and acrosome reaction (AR) of post-thaw bovine spermatozoa. Spermatozoa were incubated for 180 min in capacitation medium supplemented with (i) 1 mug/ml OE; (ii) 1 mug/ml P4; (iii) 1 mug/ml OE and 1 mug/ml P4; (iv) 1 mug/ml OE and 5 mug/ml Hep; (v) 1 mug/ml P4 and 5 mug/ml Hep; (vi) 1 mug/ml OE, 1 mug/ml P4 and 5 mug/ml Hep. At predetermined time intervals aliquots were taken to assess sperm plasma membrane scrambling, or capacitation (AR induced by lysophosphatidylcholine) in spermatozoa. The second experiment was aimed to study the effects of OE, P4 and OE/P4 as potential inducers of AR in Hep-capacitated spermatozoa. Plasma membrane scrambling was assessed by a flow cytometer, using Merocyanine staining. Acrosomal status and viability of spermatozoa were evaluated under epifluorescence microscope with Ethidium homodimer-1/peanut agglutinin fluorescein isothiocyanate staining method (EthD-1/PNA-FITC). The results show that OE, P4 and a combination of OE/P4 at concentrations used did not affect sperm viability. Heparin significantly (p < 0.001) increased sperm plasma membrane scrambling of OE and P4-treated spermatozoa. P4 significantly affected the rate of sperm capacitation (p < 0.001) and AR (p < 0.05), but OE expressed membrane-stabilizing properties (p < 0.05). It can be concluded that in frozen-thawed bovine spermatozoa OE presents plasma membrane stabilizing properties that can be abolished by Hep, but not by P4. Progesterone possesses capacitating and AR-inducing properties in frozen-thawed bovine spermatozoa that can be alleviated by OE.     

Determination of sensitivity of Mycoplasma hyosynoviae to tylosin and selected antibacterial drugs by a microtiter technique.

A microtiter technique was used for determination of the sensitivity of Mycoplasma hyosynoviae to antibiotics and other drugs. Use of a biphasic agar-broth medium in microtiter plates allowed direct visualization of growth. Results were more reproducible with this system than when broth alone was used and evaluation based on color change was required. Attempts to adapt the test for use with Mycoplasma hyorhinis were not successful. Minimal inhibitory concentrations of 12 drugs and drug combinations for 12 strains of M. hyosynoviae are presented. Drugs with the lowest minimal inhibitory concentrations were tylosin (0.37 mcg/ml)and lincomycin (0.88 mcg/ml), both of which have been used for treatment and control of M. hyosynoviae arthritis. Comparison of the minimal inhibitory concentrations of tylosin for 43 isolates of M. hyosynoviae obtained in 1959 and 1960 and from 1966 through 1971 indicated the possibilty of decreasing sensitivity to the drug although differences between recent isolates and earlier ones were not statistically significant.     

Acrosomal ultrastructure of stallion spermatozoa cryopreserved with ethylene glycol using two packaging systems

The present experiments aimed to examine the substitution of glycerol (G) by ethylene glycol (E) as a cryoprotective agent for stallion spermatozoa. Two different ethylene glycol concentrations (5% and 10%) and also the association of glycerol (2%) and ethylene glycol (3%) (E/G) were studied (Experiment 1). In Experiment 2, two packing systems (0.5 x 4.0 ml) were evaluated using both cryoprotectors. In both experiments, the sperm membrane integrity after freezing was evaluated using transmission electron microscopy. The mean post-thaw motility was 34.25, 36.5, 29.25 and 34.75% for G5%, E5%, E10% and E/G, respectively. It was observed that the percentage of motile spermatozoa was significantly smaller (P<0.05) when semen was processed with E10%. A decrease in the acrosome integrity was observed in frozen thawed spermatozoa from all treated groups. It was observed that 28.0, 22.5, 25.5 and 22.5% of the sperm cells had a normal acrosome following freezing with G5%, E5%, E10% and E/G, respectively. Undulation of the outer acrosomal membrane, acrosomal swelling and loss of acrosomal content density and homogeneity were the most evident ultrastructural alterations observed. In Experiment 2, the post-thaw motility was higher (P<0.05) for sperm frozen in 0.5 ml straws than in 4.0 ml straws, regardless of the cryoprotector used. The ultrastructural evaluation showed 26.7 and 16.0% of intact acrosomes for sperm frozen in 0.5 ml and 4.0 ml straws, respectively. We concluded that ethylene glycol has similar cryoprotective properties to glycerol and that utilisation of 0.5 ml straws improved the ability of horse sperm cells to withstand damage after the cryopreservation process.     

Antibiotic susceptibilities of recent isolates of Mycoplasma bovis in Belgium

The susceptibilities of 40 recent Belgian field isolates of Mycoplasma bovis to 10 antimicrobial agents were assessed. Tiamulin was the most active antimicrobial agent against M bovis, with an initial inhibitory concentration (IIC50) of 0.06 microg/ml, but it is not licensed for the treatment of cattle. All three fluoroquinolones tested (danofloxacin, enrofloxacin and marbofloxacin) were effective against strains of M bovis, and had a minimum mycoplasmacidal concentration (MMC50) less than or equal to 1 microg/ml. Gentamicin was poorly effective, having an IIC50 of 8 microg/ml. Many strains of M bovis were resistant to tylosin, spectinomycin, lincomycin, tetracycline and oxytetracycline.     

线粒体靶向抗氧化剂Mitoquinone对湖羊冻精损伤的保护作用

旨在研究线粒体靶向抗氧化剂Mitoquinone（MitoQ）对湖羊冷冻精子的保护作用。本研究选择健康的成年种公羊精液,将其分成6等份。不含MitoQ者设为对照组（M0）,M1、M2、M3、M4和M5组分别为含50、100、150、200和400 nmol·L^-1MitoQ的添加组。精子经冷冻解冻后检测活率、活力、质膜完整率、顶体完整率和线粒体活性等精子质量指标,同时进行超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）、活性氧（ROS）、丙二醛（MDA）等抗氧化指标检测。结果表明,当MitoQ添加的浓度为150 nmol·L^-1（M3组）时,其解冻后精子的活率、活力、质膜完整率、顶体完整率和线粒体活性最高,分别达55.00%、52.34%、48.32%、54.51%和51.28%,其线粒体活性显著高于其他组（P<0.05）。M3组解冻后精子的SOD和GSH-Px值分别为203.90 U·mL^-1和123.62 U·L^-1,两者均显著高于M0、M1、M4和M5组（P<0.05）;M3组解冻后精子的ROS和MDA值分别为298.34 U·mL^-1和4.99 nmol·L^-1,显著低于其他组（P<0.05）。当MitoQ的添加浓度提高至200（M4组）和400 nmol·L^-1（M5组）时,冻精质量开始下降,并表现为对精子的氧化损伤。在湖羊冷冻精液中,添加150 nmol·L^-1的MitoQ可显著降低精子氧化损伤,提高冻精品质,当MitoQ的添加浓度超过200 nmol·L^-1时对冷冻精子没有保护作用。     

Distinct Effects of Boar Seminal Plasma Fractions Exhibiting Different Protein Profiles on the Functionality of Highly Diluted Boar Spermatozoa

The aim of this study was to evaluate how different protein profiles of seminal plasma (SP) fractions affect sperm functionality in vitro. Ejaculates from three boars were separated into six fractions. The fractions differed from each other in their sperm content, in their total SP protein content, and their spermadhesin PSP-I/PSP-II and heparin-binding protein (HBP) concentrations. Spermatozoa were mainly recovered in fraction 2 (sperm-rich fraction, >1800 × 10⁶ spermatozoa/ml), whereas the pre-sperm fraction 1 and the post-sperm fractions 4–6 contained low numbers of spermatozoa (<500 × 10⁶/ml). Except in fraction 2, the total SP protein concentration and the concentration of both, spermadhesin PSP-I/PSP-II and the HBPs increased with fraction order. Distinct time-dependent effects were observed on motility characteristics and membrane integrity of highly diluted boar spermatozoa upon incubation with a 10% dilution of the SP from each fraction. The highest sperm viability was recorded after exposure for 5 h to fraction 2, followed by fractions 1 and 3. The percentages of motile spermatozoa also differed significantly among fractions after 5 h of incubation. Spermatozoa incubated with SP of fractions 1–3 showed the highest percentage motility. We conclude that different SP fractions exert distinct effects on the functionality of highly diluted boar spermatozoa. Fractions 1–3 appear to promote sperm survival, whereas fractions 4–6 seem to be harmful for preserving the physiological functions of highly diluted boar spermatozoa.     

Colonisation pattern of the respiratory tract of calves by Mycoplasma dispar

Eight conventionally reared, 1- to 11-week old Ayrshire calves were naturally infected by a strain of Mycoplasma dispar (M. dispar). The colonisation was quantitatively followed by nasal swab samples, transtracheal aspiration samples and by the examination of the whole of the respiratory tract for mycoplasmas at slaughter after a follow-up period of 7–10 months.The fairly uniform pattern of the colonisation by M. dispar was revealed: A high degree of colonisation, measuring 10⁵–10⁸ colour change units (ccu) per nasal sample, lasted for a period of 2–5 months and was followed by a slow decrease in titres. Seven of the calves still harboured M. dispar in their respiratory tracts at slaughter. Intermittently obtained transtracheal aspiration samples were all positive for M. dispar and the titres were regularly higher than those for the simultaneously taken nasal samples indicating a high ability of M. dispar to continuously colonize the more distal parts of the respiratory tract. It was demonstrated that the sensitivity of nasal swabbing in the detection of M. dispar infection largely depended on the phase of colonisation : The method was good for the detection of a fairly recent infection of M. dispar, but inadequate for detection of low grade carriers.In various phases, the calves also became infected by Mycoplasma bovirhinis and Acholeplasma laidlawii. Their ability to colonize the whole respiratory tract was lower than that of M. dispar.