Gibberellins and antheridiogen on sex in Blechnum spicant L

The role of gibberellins (GAs) in determining sex in the gametophyte of the fern Blechnum spicant L. was studied through (a) the effect of exogenous GA(4+7) and GA3 (b) quantitation of the endogenous levels of GA1, GA3, GA4, GA7, GA9, and GA20 in male and female gametophytes, and (c) the effect of flurprimidol, a GAs biosynthesis inhibitor of the steps of oxidation of ent-kaureno to ent-kaurenoic acid. Our results show that GA(4+7) had a slight effect of inducing either male or female sexual organs, antheridia and archegonia, respectively. The endogenous GAs content was not significantly different between sexes, but the GA4, GA7, and GA20 levels were raised above those of the other GAs in both sexes. Neither antheridiogen biosynthesis nor antheridia formation was inhibited by flurprimidol. Gametophytes regenerated from homogenized mature gametophytes (HG) show a different physiological behavior than spore-derived gametophytes. In the first case, gametophytes are males and synthesize antheridiogen before they attain maturity, in contrast to what occurs in spore-derived gametophytes which are females and synthesize antheridiogen when mature.

Exogenous and endogenous growth regulators on apogamy in Dryopteris affinis (Lowe) Fraser-Jenkins sp. affinis

This work showed for the first time the relationship between the effect of exogenous auxins and gibberellins on apogamy in Dryopteris affinis (Lowe) Fraser-Jenkins sp. affinis and its endogenous contents during early apogamic events. The addition of NAA (0.53 and 5.37 microM) or GA(3) 2.8 microM to an MS solid medium significantly increased apogamous sporophyte formation. BA induced brown callus that regenerated sporophytes in a hormone-free medium. The endogenous contents of GA(1), GA(3), GA(4), GA(7), GA(9) and IAA were determined by GC-MS in gametophytes cultured on MS solid medium, before and during early stages of apogamous embryo development. The accumulation of both GA(9) and IAA before embryo development was evident as high levels of GA(4) in the earliest analysed stage of embryo development and high levels of GA(3) in elongating shoots were found. The role of gibberellins on apogamy was also supported by data showing a decrease in the percentage of gametophytes developing embryos because of the addition of flurprimidol to the culture medium.

Experimental Study of the Interplay between Long-Range Electron Transfer and Redox Probe Permeation at Self-Assembled Monolayers: Evidence for Potential-Induced Ion Gating

Evidence for the competition between long-range electron transfer across self-assembled monolayers (SAMs) and incorporation of the redox probe into the film is reported for the electroreduction of Ru(NH(3)) at hydroxyl- and carboxylic-acid-terminated SAMs on a mercury electrode, by using electrochemical techniques that operate at distinct time scales. Two limiting voltammetric behaviors are observed, consistent with a diffusion control of the redox process at mercaptophenol-coated electrodes and a kinetically controlled electron transfer reaction in the presence of neutral HS-(CH(2))(10)-COOH and HS-(CH(2))(n)()-CH(2)OH (n = 3, 5, and 10) SAMs. The monolayer thickness dependence of the standard heterogeneous electron transfer rate constant shows that the electron transfer plane for the reduction of Ru(NH(3)) at hydroxyl-terminated SAMs is located outside the film | solution interface at short times. However, long time scale experiments provide evidence for the occurrence of potential-induced gating of the adsorbed structure in some of the monolayers studied, which takes the form of a chronoamperometric spike. Redox probe permeation is shown to be a kinetically slow process, whose activation strongly depends on redox probe concentration, applied potential, and chemical composition of the intervening medium. The obtained results reveal that self-assembled monolayers made of mercaptobutanol and mercaptophenol preserve their electronic barrier properties up to the reductive desorption potential of a fully grown SAM, whereas those of mercaptohexanol, mercaptoundecanol, and mercaptoundecanoic acid undergo an order/disorder transition below a critical potential, which facilitates the approach of the redox probe toward the electrode surface.

Capillary electrophoresis determination of loratadine and related impurities

While HPLC has traditionally been the method of choice for purity determination of pharmaceutical substances, capillary electrophoresis (CE) offers a different selectivity and hence it is a complementary technique to HPLC. Loratadine, an antihistamine, could include in its raw material seven impurities that ought to be separated, identified and quantified for drug development and quality control. As a complementary tool for undoubtful identification, a CE method has been developed. The separation was carried out with an uncoated fused-silica capillary (57 cm x 50 microm ID) and was operated at 20 kV potential. Temperature was maintained at 25 degrees C. The final separation buffer was prepared with 100 mM H(3)PO(4) made up to pH 2.5 with NaOH and with 10% acetonitrile added (v/v). Impurities can be detected at the 0.1% level of the active and validation parameters for linearity accuracy and precision are adequate for all the analytes and that permits to consider the method reliable and suitable for application to long-term stability and purity studies.

Electrochemical oxidation of 6-propionyl-2-(N,N-dimethylamino)naphthalene (prodan) in acetonitrile on Pt electrodes: Reversible dimerization of prodan radical cations

The electrooxidation of 6-propionyl-2-(N,N-dimethylamino)naphthalene (prodan) has been investigated for the first time. It has been performed on both conventional size platinum electrodes and platinum ultramicroelectrodes in acetonitrile by cyclic voltammetry with convolution analysis and controlled-potential electrolysis. The voltammetric responses at room temperature are similar to those corresponding to a kinetically controlled anodic electron-transfer process. Cyclic voltammetry measurements were also carried out at different concentrations of prodan and at different temperatures. Chemical transformation of the radical monocation formed after the electrochemical oxidation of prodan, as deduced from reverse controlled potential bulk electrolysis and cyclic voltammetry measurements, gives evidence for the reversible dimerization of prodan radical cations. Both diagnostic criteria and digital simulation confirm that radical–radical coupling is the reversible chemical reaction coupled to the initial electron transfer step, to give the corresponding dimeric dication. The kinetic and thermodynamic parameters for the first electron transfer reaction and the dimerization process were estimated from digital simulation at 293 K. Values of 8.0 × 106 M–1 and 3.2 × 105 M–1 s–1 were determined for the dimerization reaction equilibrium constant and the dimer formation rate constant, respectively. The diffusion coefficient of prodan was determined from both limiting currents from convoluted cyclic voltammograms as well as limiting currents on ultramicroelectrodes. For such cases where the electron number exchanged in the electrode process is unknown, a method derived from the combination of data previously indicated is also proposed to obtain the diffusion coefficient of the electroactive species.Key words: prodan, cyclic voltammetry, reaction mechanism, reversible dimerization, electron transfer reactions, radical cation.

LC determination of loratadine and related impurities

Loratadine, an antihistamine, could include in its raw material seven impurities that ought to be separated identified and quantified for drug development and quality control. A HPLC method employing a SymmetryShield RP8 column has been developed and validated for loratadine and related compounds measurement, the last ones under the 0.1% level. The mobile phase consisted of methanol-buffer A (65:35, v/v), being buffer A: H(3)PO(4) 10 mM (H(2)O) brought up to pH 7.00 with triethylamine. UV detection was performed at 244 nm. Validation parameters for linearity, accuracy and precision are in agreement with ICH guidelines for all the analytes and that permits to consider the method reliable and suitable for application to long-term stability and purity studies.

[Value of gray scale ultrasonography in the early diagnosis of urologic complications of renal transplantation]

OBJECTIVE

To determine the significance of gray scale ultrasound as a tool for diagnosis, follow-up and treatment of urological complications of renal transplantation based on the experience of our institution.

METHODS

A retrospective, longitudinal and observational study was carried out. We reviewed the patients' perioperative ultrasound scans and their respective urological complications from January 1, 1982 to January 1, 2000. The patients were consecutively taken from the kidney transplant registry of the Urology and Nephrology and Transplant Departments. We describe the ultrasound findings of normal functioning grafts as well as those with urological complications, such as fluid collections (lymphocele, hematoma, urinoma and abscess), uronephrosis and its possible causes, and symptomatic vesicourethral reflux.

RESULTS/CONCLUSIONS

Diagnostic and therapeutic algorithms in kidney transplant patients have been changed since the advent of ultrasound in our country in 1981. Rapid diagnosis and better therapeutic options have been the hallmarks of ultrasound. Added advantages are: it is low-cost, non-invasive, not time consuming. It can be performed regardless of kidney function, can be repeated as many times as required, subsequent scans can be compared. It can be carried out in special care units. The superficial location of the graft makes it highly sensitive. Its disadvantages are low specificity to identify either the nature of the fluid collections or the precise site of urinary tract obstruction, apart from depending on the skill of the operator. Specialists should be familiar with the surgical anatomy of the kidney graft and its variations in order to utilize completely its diagnostic and therapeutic potentials.

Antibodies anti-Chlamydia pneumoniae and anti-Mycoplasma pneumoniae in patients with negative serology for hantavirus. Retrospective study

The seroprevalence of Chlamydia pneumoniae and Mycoplasma pneumoniae in hantavirus seronegative patients, who had symptoms and signs compatible with pneumonia was established. For this purpose we used the indirect fluorescent antibody test. Titers > or = 1:16 for C. pneumoniae and M. pneumoniae were found in 8.6% and 17.1% of the serum, respectively, showing evidence of recent or current infection.

[Tuberculosis in the V Sanitary Zone of Buenos Aires Province. Analysis of its trends between 1984 and 1996]

Tuberculosis (TB) continues to be a serious health problem in most of the districts in the 5th Sanitary Region of Buenos Aires Province (RSV) which is located in North Buenos Aires City suburbs. The aim of this study was to analyse and compare the evolution of the TB epidemiological situation in ten districts, in a thirteen year period (1984-96) and to analyse possible reasons for differences. The average annual variation (VAP) of morbidity rate was calculated in order to estimate the trends of TB in these communities along time. Reporting to the National and Provincial TB Control Programmes of TB cases is mandatory for physicians and these data were used as a source of information for the number of cases and rates. A statistical analysis was performed. Our results showed that the VAP value for the whole RSV was lower than -5.0%. On this basis several districts were identified as having a TB critical situation. The proportion of smear positive cases among TB patients reported decreased during this period, suggesting that smear microscopy was being poorly used as a diagnostic tool for TB. Furthermore, the cure rates of the patients attained--in average--only 60.0% and several warning indicators (IA)--like TB meningitis cases and mortality due to TB in people younger than thirty years old, as well as TB--HIV/AIDS association--have been observed to grow in several districts. Previous world global experience and those obtained in other provinces in our own country, suggest that the unique possible strategy for modifying this situation, is to set up the directly observed treatment (DOTS), according to World Health Organization/International Union Against Tuberculosis and Lung Diseases (WHO IVATLD) recommendations, in order to achieve the control of TB.

Expression of invasiveness of Campylobacter jejuni ssp. jejuni after serial intraperitoneal passages in mice

We investigated the possibility of inducing the expression of invasiveness in 10 non-invading, laboratory-adapted Campylobacter jejuni ssp. jejuni strains, after serial intraperitoneal (i.p.) passage in mice. All the strains expressed invasive capacity after the first passage, with an increase in invasion rates and the number of internalized bacteria after each passage. These results suggest that i.p. passage enhances the expression of invasiveness in C. jejuni ssp. jejuni strains.

Antimicrobial susceptibility of Campylobacter jejuni subsp. jejuni assessed by E-test and double dilution agar method in Southern Chile

The susceptibility patterns of 108 Campylobacter jejuni subsp. jejuni clinical strains, to six antimicrobial agents was determined by using the E-test and the double dilution agar methods. Using both methods, no strain was found to be resistant to ciprofloxacin, erythromycin and gentamicin, but two (1.8%) were resistant to tetracycline and all to aztreonam. Seven (6.5%) strains were resistant to ampicillin by the E-test and five (4.6%) by the double dilution agar method and by both methods. No great discrepancies were observed between both methods.

Heart transplantation: influence of the surgical technique on sinus function

This study analyzes the influence of the surgical technique on the development of sinus dysfunction. Cycle length, corrected sinus node recovery time, and sinoatrial conduction time were determined in 4 groups of dogs under the following conditions: group 1, controls; group 2, subjected to heterotopic heart transplantation with conservation of atrial anatomy; group 3, subjected to orthotopic heart transplantation by using a standard technique; and group 4, treated as in group 3, but with an ischemic time of 24 hours. The cycle length was prolonged in all the treated groups when compared with the controls (P < .01), an effect attributed to the disconnection of the autonomic nervous system during the transplantation procedure. The corrected sinus node recovery time and sinoatrial conduction time were significantly longer in all the animals in groups 3 and 4 when compared with those of groups 1 and 2 (P < .01); however, there were no significant differences between groups 3 and 4 or between groups 1 and 2. These results suggest that the atrial anatomy play a more relevant role than the ischemic time in the origin of sinus dysfunction occurring after orthotopic heart transplantation.

[The relationship of Campylobacter jejuni subsp. jejuni enterotoxigenicity and the increase of cAMP and electrolyte changes in the rat intestine]

BACKGROUND

Small intestine alterations produced by the enterotoxigenic capacity of Campylobacter jejuni subsp. jejuni are similar to the hydric, electrolytic and pathological changes caused by choleraic and thermolabile Escherichia coli toxins.

AIM

To study the enterotoxigenic capacity of 4 strains of Campylobacter jejuni subsp. jejuni using the intestinal loop model.

MATERIAL AND METHODS

Rat intestinal loops were inoculated with culture filtrates of the four strains. Enterotoxigenicity was assessed by fluid accumulation, the increase in Na+ and Cl- in the loop fluid, and cAMP increase in loop tissues. An enterotoxigenic Escherichia coil strain and sterile Brucella both were used as positive and negative controls, respectively.

RESULTS

The filtrates of two strains produced fluid accumulation in the loops, significantly increased Na+ and Cl- secretion to the intestinal lumen and increased tissue cAMP levels.

CONCLUSIONS

Some strains of Campylobacter jejuni subsp. jejuni are able to show enterotoxigenicity in vivo, increasing cAMP levels in the intestinal cells and altering electrolyte exchange mechanisms.

[Primary ureteral amyloidosis]

OBJECTIVE

Two additional cases of primary ureteral amyloidosis are described. The current literature and clinical classification of the disease are reviewed.

METHODS

Over a period of 18 months, we observed two cases of organic ureteral stenosis whose etiology was difficult to determine. The first case warranted a nephroureterectomy due to the condition of the compromised urinary tract. Analysis of the surgical specimen showed histological evidence of ureteral amyloidosis. In the second case, the previous experience allowed a preoperative diagnosis to be made, an exceptional situation that permitted conservative surgery. Characterization of the amyloid proteins was done in both cases with immunochemical study by Western Blot.

RESULTS

Two patients with primary ureteral amyloidosis were surgically treated. The first case underwent complete excision of the urinary tract. The second case, who had a single kidney, was treated by conservative surgery. In both cases we identified a fragment of the lambda light chain of immunoglobulin by Western Blot characterization as previously reported in localized amyloidosis.

CONCLUSIONS

Although ureteral amyloidosis is an infrequent disease, it should be seriously considered in the differential diagnosis of organic ureteral stenosis in order to avoid unnecessary excision. To our knowledge, these are the first cases of ureteral amyloidosis with immunochemical characterization of the amyloid protein.

Article

The acid dissociation constants for alternariol monomethyl ether (AME), altertoxin-I (ATX-I), and alternariol (AOH), three of the Alternaria alternata genus mycotoxins, are estimated through conventional UV-VIS spectroscopic studies at different pH values. Experimental variations of absorbance as a function of pH at a given wavelength were fitted by using the exact equations that describe the systems studied. Good agreement between the experimental absorbance vs. pH plots and the curves generated by the fitting process was found. A comparison between the acidic constants for the first step of dissociation of these mycotoxins and the value for the acidic constant of phenol is discussed by assuming that phenolic structures are responsible for the acidity of these mycotoxins.Key words: mycotoxins, alternariol monomethyl ether, altertoxin-I, alternariol, acidic constants.

Cape Town solution in prolonged myocardial preservation: structural and ultrastructural study

This study deals with myocardial preservation after 24 hours of continuous, hypothermic and oxygenated perfusion with Cape Town (CT) solution, focusing on the morphological changes produced by preservation and reperfusion, and their possible relationship to the composition of the solution and the immediate hemodynamic findings after orthotopic heart transplantation in dogs. After preservation, aside from mild or moderate mitochondrial changes, the most relevant lesions included edema and vasoconstriction. Reperfusion was followed by the development of areas of necrosis forming contraction bands and an increment in the mitochondrial damage; the intercalated disks conserved their normal structure; edema became more prominent and was invariably accompanied by hemorrhage; vasoconstriction was very pronounced and was accompanied on occasion by evidence of capillary rupture; and inflammatory cells were observed in the interstitium. These results indicate that colloid must be added to Cape Town solution and that reperfusion probably requires selective approaches to deal with vasoconstriction and inflammation.

Arterial blood gases and acid-base balance in geriatric dogs

To compare arterial blood gas pressures and acid-base balance in geriatric and young adult dogs, 23 clinically healthy aged dogs (> 10 years old) and 16 young adult dogs (two to four years old) were studied. Blood gases (PaO2 and PaCO2), pH, Na, K, Ca and Cl were measured in arterial blood samples using selective electrodes. Haemoglobin was quantified with a co-oximeter. Total proteins and phosphorus were measured by spectrophotometry in plasma. The alveolar to arterial PO2 gradient (P(A-a)O2), bicarbonate, anion gap and the base excess of blood were calculated. Quantitative analysis of acid-base balance was carried out by calculating unidentified anions. Old dogs had significantly higher P(A-a)O2 than young dogs (2.5 +/- 0.3 versus 1.4 +/- 0.3 KPa). Although the differences were not significant, aged dogs also had a lower PaO2. No differences were detected in PaCO2, pH, Na, K, Ca, Cl, haemoglobin, phosphorus, bicarbonate and base excess of blood. Plasma proteins were higher in old dogs than in young dogs (7.1 +/- 0.2 versus 6.5 +/- 0.2 g dl-1). Anion gap was increased in aged dogs; however, no changes were found in unidentified anions. In conclusion, an increase in P(A-a)O2 has been identified in a group of geriatric dogs. No major changes have been found in the acid-base balance of aged dogs.

Structural and ultrastructural study of the myocardium after 24-hour preservation in University of Wisconsin solution

This study deals with myocardial preservation after 24 hours of continuous perfusion with University of Wisconsin (UW) solution, focusing on the morphological changes produced by preservation and reperfusion, and their possible relationship to the composition of the solution and the immediate hemodynamic findings after orthotopic heart transplantation in dogs. Following preservation, the histological images of the myocardium were normal in almost every case. After revascularization, although 50% of the hearts recovered preoperative functional levels, there were relevant histological changes in all of them. These changes consisted of interstitial edema, damage to at least 50% of the mitochondria, presence of contraction bands, loss of intercellular junction structure and vasoconstriction. According to these results, the association of continuous perfusion and UW solution appears to be effective during the ischemic period of prolonged myocardial preservation, but not during reperfusion. Perhaps the proportion of viable hearts could be increased by preventing vasoconstriction.

Occurrence of thermotolerant Campylobacter species in domestic and wild monkeys from Peru

The isolation rate of thermotolerant campylobacters in pet monkeys and wild monkeys was established. Campylobacter spp. were isolated in 31.9% of the first (pet) group, being less frequent (20.9%) in the second (wild) (P > 0.05). In both groups, only biovars I and II of C. jejuni ssp. jejuni and both biovars of C. coli were isolated (Lior's scheme). Campylobacter lari was not isolated. The results show that domestic and wild monkeys can harbour Campylobacter in their intestinal tract and would be considered as reservoirs of these bacteria.

Use of interferon-alpha in laryngeal papillomatosis: eight years of the Cuban national programme

Laryngeal papillomatosis is one of the first diseases where interferon (IFN) was found to be effective. In 1983, a programme for the treatment of all such cases started in Cuba. Up to December 1991, 125 patients (92 children, 33 adults) have been treated: 102 with leucocyte IFN-alpha, 12 with recombinant IFN-alpha-2b, and 11 have received both preparations. Case management consisted of surgical removal of the lesions followed by an IFN schedule starting with 10(5) IU/kg of weight in children or 6 x 10(6) IU in adults, i.m. daily. The dose was progressively reduced, as long as no relapses occurred. At the end of the one-year schedule the doses were reduced to 5 x 10(4) IU/kg in children or 3 x 10(6) IU in adults, weekly. If there was a relapse, it was removed surgically and the patient returned to a higher dose level. Most cases (89; 71 per cent) have not relapsed after the treatment; 60 of them have been followed for more than three years. In those with relapses, the frequency of recurrence decreased in all but four patients. The treatment seemed to be more effective if initiated less than three months after the disease onset. The tracheostomy could be removed in five out of seven patients who needed it before the IFN treatment and was necessary in only three new cases during IFN treatment. In two of these, decannulation was possible later on. In a total of 14 patients relapses persisted after several cycles of IFN treatment. They were considered resistant to such treatment. No severe side effects were reported. The most frequent ones were fever, drowsiness, increased bronchial secretion, chills and headache. The establishment of this programme has maintained the disease under control in Cuba.

[Intervention of Campylobacter jejuni subsp. jejuni flagella in the adhesion to cellular cultures: bacteriological and immunological evidence]

The participation of the flagella of a virulent strain (O52) of Campylobacter jejuni subsp. jejuni in the adhesion to HEp-2 cells and their inhibition by means of homologous polyclonal antibodies, monoclonal anti-flagella antibodies and colostral natural antibodies (IgA) was studied. An aflagellated strain (T1) was used as negative control. Adhesion was observed in higher rates with O52 strain (72%) than with T1 strain (27.5%). Polyclonal, monoclonal and colostral antibodies inhibited O52 strain adhesion in more than 70% (p < 0.001). T1 strain adhesion was inhibited only by polyclonal and colostral natural antibodies. Our results suggest that the flagella of C. jejuni subsp. jejuni could participate effectively in the adhesion process. However, the inhibition of T1 strain by polyclonal and colostral antibodies suggests the existence of other binds of adhesins in the bacterial surface.

Isolation of thermotolerant species of Campylobacter from commercial chicken livers

The qualitative and quantitative contamination levels of Campylobacter spp. in frozen commercial chicken livers were assessed. From the 126 samples studied, 117 (92.9%) were positive for Campylobacter spp. C. coli was isolated more frequently (78.6%) than C. jejuni (21.4%). The MPN method showed that Campylobacter contamination levels ranged from 10 to > 230 bacteria/100 ml of liquid exuded by livers.

[Participation of Campylobacter jejuni flagellar epitopes in cellular adhesion]

Using a flagellated (052) and an aflagellated (T-1) strains we studied the participation of flagellar epitopes of C. jejuni in the adhesion to HEp-2 cells in vitro. Strain 052 was significantly more adherent than strain T-1. When adhesion assays were carried out with antiflagella monoclonal antibodies, strain 052 showed inhibition of their adhesive capacity that varied between 64.3 and 92.9%. With an ELISA test it was demonstrated that those monoclonal antibodies were specific and directed exclusively against flagellar epitopes of strain 052 being unreactive with strain T-1. Our results show that flagellar epitopes could participate in the adhesion process suggesting that flagella could be involved in the installation of the infectious process.

Lesions of the medial prefrontal cortex and sexual behavior in the male rat

Lesions of the cerebral cortex near the midline in the frontal region appearing to destroy most of the cingulate cortex and adjacent prefrontal areas had profound effects on male rat sexual behavior. At the first postoperative tests, one week after the lesion, the mount and intromission latencies were extremely long (> 60 min). They continued elevated at every fortnightly test until postlesion week 13, when they were no longer different from controls. However, the proportion of animals that intromitted or ejaculated was reduced at this time. The lesion had a slight effect on the number of intromissions and on the intromission ratio, but did not reliably modify other parameters of sexual behavior in those males that copulated after operation. These data suggest that the medial prefrontal cortex is important for the initiation of sexual behaviour but less so for its execution. It is proposed that the elaboration and/or interpretation of environmental stimuli are rendered deficient by the lesion. Consequently, sexual behavior is activated only with difficulty. This coincides with the arousal hypothesis proposed by Beach [8]. There appears to exist a spontaneous recovery of the mechanisms responsible for the activation of sex behavior because the lesioned group was not different from the sham or intact groups 13 weeks postlesion. Remaining cortical tissue or other brain structures may compensate for the initial deficiencies. However, the lesion's effect on intromission behavior did not diminish with time. This could suggest that possible motor deficiencies produced by the lesion are irreversible.

[Isolation of thermotolerant species of Campylobacter from 2 populations of chickens bred in confinement and at liberty]

The isolation rates of thermotolerant Campylobacter species in free-ranging domestic chickens and confined chickens from Iquitos city, Peru, were determined. Campylobacter spp. were isolated in 54.0% of the former group of chickens, being less frequent (35.0%) in the latter (p < 0.05). Of the classical thermotolerant species, C. jejuni and C. coli were the most frequent. However, the presence C. lari suggests that the chickens might be an important reservoir of this bacterium.