Zoonotic transmission of tuberculosis between pastoralists and their livestock in South-East Ethiopia

Despite huge global efforts in tuberculosis (TB) control, pastoral areas remain under-investigated. During two years sputum and fine needle aspirate (FNA) specimens were collected from 260 Ethiopian pastoralists of Oromia and Somali Regional States with suspected pulmonary TB and from 32 cases with suspected TB lymphadenitis. In parallel, 207 suspected tuberculous lesions were collected from cattle, camels and goats at abattoirs. All specimens were processed and cultured for mycobacteria; samples with acid-fast stained bacilli (AFB) were further characterized by molecular methods including genus and deletion typing as well as spoligotyping. Non-tuberculous mycobacteria (NTM) were sequenced at the 16S rDNA locus. Culturing of AFB from human sputum and FNA samples gave a yield of 174 (67%) and 9 (28%) isolates, respectively. Molecular typing was performed on 173 of these isolates and 160 were confirmed as Mycobacterium tuberculosis, three as M. bovis, and the remaining 10 were typed as NTMs. Similarly, 48 AFB isolates (23%) yielded from tuberculous lesions of livestock, of which 39 were molecular typed, including 24 M. bovis and 4 NTMs from cattle, 1 M. tuberculosis and 1 NTM from camels and 9 NTMs from goats. Isolation of M. bovis from humans and M. tuberculosis from livestock suggests transmission between livestock and humans in the pastoral areas of South-East Ethiopia.     

Prevalence and fingerprinting of Listeria monocytogenes strains isolated from raw whole milk in farm bulk tanks and in dairy plant receiving tanks

The incidence of Listeria species in raw whole milk from farm bulk tanks and from raw milk in storage at a Swedish dairy plant was studied. Listeria monocytogenes was found in 1.0% and Listeria innocua was found in 2.3% of the 294 farm bulk tank (farm tank) milk specimens. One farm tank specimen contained 60 CFU of L. monocytogenes ml(-1). L. monocytogenes was detected in 19.6% and L. innocua was detected in 8.5% of the milk specimens from the silo receiving tanks at the dairy (dairy silos). More dairy silo specimens were positive for both Listeria species during winter than during summer. Restriction enzyme analysis and pulsed-field gel electrophoresis were applied to 65 isolates of L. monocytogenes, resulting in 16 different clonal types. Two clonal types were shared by the farm tank milk and the dairy silo milk. All except one clonal type belonged to serovar 1/2a. In the dairy silo milk five clonal types were found more frequently and for a longer period than the others. No Listeria species were found in any other samples from the plant.     

Seroprevalence and risk factors associated to Mycobacterium bovis in wild artiodactyl species from southern Spain, 2006-2010

The control of bovine tuberculosis (bTB) is at a critical point in the last stage of eradication in livestock. Wildlife species recently have emerged infected with TB in Europe, particularly ungulates in the Iberian Peninsula. Epidemiological information regarding TB in wild ungulates including affected species, prevalence, associated risk factors and appropriate diagnostic methods need to be obtained in these countries. A cross-sectional study was carried out on wild artiodactyl species, including Eurasian wild boar (Sus scrofa) red deer (Cervus elaphus), roe deer (Capraelus capraelus), fallow deer (Dama dama), Spanish ibex (Capra pyrenaica hispanica) and mouflon (Ovis musimon), in Spain to assess the seroprevalence against Mycobacterium bovis or cross-reacting members of the Mycobcaterium tuberculosis complex (MTBC), and to provide information on associated risk factors. Previously, two in-house indirect enzyme linked immunosorbent assays (bPPD-ELISA and MPB83-ELISA) were developed using known TB status sera. Positive reference sera were selected from infected animals confirmed by culture. The M. bovis isolates belonged to spoligotypes SB0121, SB0120, SB0295, SB0265 and SB0134. Two hundred and two out of 1367 (7.5%; 95% CI: 6.1-8.9) animals presented antibodies against M. bovis by both bPPD-ELISA and MPB83-ELISA. Significantly higher TB seroprevalence was observed in wild boar compared to the other species analyzed. Interestingly, seropositivity against M. bovis was not found in any out of 460 Spanish ibex analyzed. The logistic regression model for wild boar indicated that the seropositivity to M. bovis was associated with age, location and year of sampling, while the only risk factor associated with M. bovis seroprevalence in red deer and fallow deer was the age. The seroprevalence observed indicates a widespread exposure to MTBC in several wild artiodactyl species in southern Spain, which may have important implications not only for conservation but also for animal and public health.     

Amplified ribosomal DNA restriction analysis in the differentiation of related species of mycobacteria

This study explores the potential of the amplified ribosomal DNA restriction analysis (ARDRA) for intra- and interspecies identification of the genus Mycobacteria. A set of primers was used to amplify part of the 16S and 23S rDNA as well as the 16S-23S rDNA spacer from 121 isolates belonging to 13 different mycobacterial species. Restriction analysis was carried out with five different restriction enzymes, namely CfoI, HaeIII, RsaI, MspI and TaqI. Restriction digestion of the PCR product using CfoI enabled differentiation between 9 of the 13 mycobacterial species, whereas the remaining four enzymes differentiated between 7 of these 13 species. None of the five enzymes distinguished between different isolates of Mycobacterium tuberculosis or between species within the M. tuberculosis complex i.e., M. tuberculosis, M. bovis, M. bovis BCG and M. africanum. Although ARDRA analysis of the 16S-23S rDNA does not seem to have a potential for intraspecies differentiation, it has proven to be a rapid and technically relatively simple method to recognise strains belonging to the M. tuberculosis complex as well as to identify mycobacterial species outside this complex.     

Enterotoxigenic Staphylococcus aureus in bulk milk in Norway

AIMS: To investigate the presence of enterotoxigenic Staphylococcus aureus in bulk milk and in a selection of raw milk products. METHODS AND RESULTS: Samples of bovine (n = 220) and caprine (n = 213) bulk milk, and raw milk products (n = 82) were analysed for S. aureus. Isolates were tested for staphylococcal enterotoxin (SE) production (SEA-SED) by reversed passive latex agglutination and for SE genes (sea-see, seg-sej) by multiplex PCR. Staphylococcus aureus was detected in 165 (75%) bovine and 205 (96.2%) caprine bulk milk samples and in 31 (37.8%) raw milk product samples. Enterotoxin production was observed in 22.1% and 57.3% of S. aureus isolates from bovine and caprine bulk milk, respectively, while SE genes were detected in 52.5% of the bovine and 55.8% of the caprine bulk milk isolates. SEC and sec were most commonly detected. A greater diversity of SE genes were observed in bovine vs caprine isolates. CONCLUSIONS: Staphylococcus aureus seems highly prevalent in Norwegian bulk milk and isolates frequently produce SEs and contain SE genes. Enterotoxigenic S. aureus were also found in raw milk products. SIGNIFICANCE AND IMPACT OF THE STUDY: Staphylococcus aureus in Norwegian bovine and caprine bulk milk may constitute a risk with respect to staphylococcal food poisoning from raw milk products.     

Experimental inoculation of meadow voles (Microtus pennsylvanicus), house mice (Mus musculus), and Norway rats (Rattus norvegicus) with Mycobacterium bovis

Mycobacterium bovis has a wide host range that includes several wildlife species, and this can hamper attempts to eradicate bovine tuberculosis from livestock. The purpose of this study was to determine if common rodent species, namely meadow voles (Microtus pennsylvanicus), house mice (Mus musculus), and Norway rats (Rattus norvegicus), that inhabit the bovine tuberculosis endemic area of Michigan, can be experimentally infected with M. bovis. The objectives of the study were: 1) to determine if these rodent species can be infected, and if so, to document attendant pathologic processes/pathogenesis; 2) to detect any fecal shedding of M. bovis; and 3) to evaluate the relative susceptibility of the three species to M. bovis infection. For each species (n=36) there were two treatment (n=12/group) and one or two control groups depending on species (n=6-12/group); the maximum study duration was 60 days. The meadow vole treatments consisted of high dose inocula that were given by oral or intranasal routes, whereas the house mice and Norway rats were given only oral inocula at either a high or low dose. Of the three species, meadow voles were most susceptible to M. bovis infection. Upon intranasal inoculation, all 12 voles were infected as determined by gross and microscopic lesions and culture of M. bovis from tissue and feces. Seven of the 12 meadow voles inoculated orally were infected. House mice also were susceptible; M. bovis was isolated from 14 of 24 animals. Only one Norway rat in the high dose treatment group was positive by culture and this was the only animal from which minimal attendant lesions were observed. Results of this study indicate that meadow voles and house mice can be infected with M. bovis and might serve as spillover hosts. Concerted efforts should, therefore, be made to reduce or eliminate these rodents on premises where M. bovis-infected livestock are present.     

Mycobacterium bovis identification by a molecular method from post-mortem inspected cattle obtained in abattoirs of Mato Grosso do Sul, Brazil

The presence of Mycobacterium bovis in bovine carcasses with lesions suggestive of tuberculosis was evaluated. Seventy-two carcass samples were selected during slaughter inspection procedures in abattoirs in the state of Mato Grosso do Sul, Brazil. Seventeen (23.6%) of samples showed colonies suggestive of mycobacteria that were confirmed to be acid-fast bacilli by Ziehl-Neelsen staining. Polymerase chain reaction (PCR) using primers specific for M. bovis identified M. bovis in 13 (76.5%) isolates. The PCR-restriction enzyme pattern analysis using gene encoding for the 65-kDa protein and two restriction enzymes identified the remaining four isolates that were represented by two M. tuberculosis complex and two nontuberculous mycobacteria. The results are indicative of infection of slaughter cattle by M. bovis and other mycobacteria in the state of Mato Grosso do Sul.     

Prevalence and Fingerprinting of Listeria monocytogenes Strains Isolated from Raw Whole Milk in Farm Bulk Tanks and in Dairy Plant Receiving Tanks

The incidence of Listeria species in raw whole milk from farm bulk tanks and from raw milk in storage at a Swedish dairy plant was studied. Listeria monocytogenes was found in 1.0% and Listeria innocua was found in 2.3% of the 294 farm bulk tank (farm tank) milk specimens. One farm tank specimen contained 60 CFU of L. monocytogenes ml⁻¹. L. monocytogenes was detected in 19.6% and L. innocua was detected in 8.5% of the milk specimens from the silo receiving tanks at the dairy (dairy silos). More dairy silo specimens were positive for both Listeria species during winter than during summer. Restriction enzyme analysis and pulsed-field gel electrophoresis were applied to 65 isolates of L. monocytogenes, resulting in 16 different clonal types. Two clonal types were shared by the farm tank milk and the dairy silo milk. All except one clonal type belonged to serovar 1/2a. In the dairy silo milk five clonal types were found more frequently and for a longer period than the others. No Listeria species were found in any other samples from the plant.     

Evidence of Cryptosporidium transmission between cattle and humans in northern New South Wales

Cryptosporidium is an enteric parasite of public health significance that causes diarrhoeal illness through faecal oral contamination and via water. Zoonotic transmission is difficult to determine as most species of Cryptosporidium are morphologically identical and can only be differentiated by molecular means. Transmission dynamics of Cryptosporidium in rural populations were investigated through the collection of 196 faecal samples from diarrheic (scouring) calves on 20 farms and 63 faecal samples from humans on 14 of these farms. The overall prevalence of Cryptosporidium in cattle and humans by PCR and sequence analysis of the 18S rRNA was 73.5% (144/196) and 23.8% (15/63), respectively. Three species were identified in cattle; Cryptosporidium parvum, Cryptosporidium bovis and Cryptosporidium ryanae, and from humans, C. parvum and C. bovis. This is only the second report of C. bovis in humans. Subtype analysis at the gp60 locus identified C. parvum subtype IIaA18G3R1 as the most common subtype in calves. Of the seven human C. parvum isolates successfully subtyped, five were IIaA18G3R1, one was IIdA18G2 and one isolate had a mix of IIaA18G3R1 and IIdA19G2. These findings suggest that zoonotic transmission may have occurred but more studies involving extensive sampling of both calves and farm workers are needed for a better understanding of the sources of Cryptosporidium infections in humans from rural areas of Australia.     

牛型纯化蛋白衍生物皮内变态反应试验阳性牛中分枝杆菌的分离与鉴定

为评价牛分枝杆菌纯化蛋白衍生物(purified protein derivative,PPD)单纯颈部皮内变态反应试验(single intradermal cervical tuberculin,SICT)在奶牛结核病检测中的特异性,采集54头SICT阳性牛的118份组织样品进行病原分离和鉴定。结果显示,14头SICT阳性牛样品中分离到抗酸阳性菌,占SICT阳性牛总数的25.9%(14/54)。其中,10头阳性牛样品中分离到分枝杆菌,占18.5%(10/54);1头阳性牛样品中分离到牛分枝杆菌,占1.9%(1/54)。从118份组织样品中分离到16株抗酸阳性菌,其中12株为分枝杆菌,分枝杆菌分离率为10.2%(12/118)。12株分枝杆菌中,1株为牛分枝杆菌,其余11株为禽分枝杆菌、土地分枝杆菌等非结核分枝杆菌。牛分枝杆菌与非结核分枝杆菌分别占分枝杆菌分离株的8.3%(1/12)和91.7%(11/12)。病原分离和鉴定结果表明,SICT阳性牛的牛分枝杆菌分离率较低,为确保检测结果的准确性,有必要采用其他检测方法进行验证。同时,可将分枝杆菌快速分离培养及菌种鉴定检测技术引入对皮内变态反应试验阳性牛的实验室诊断,进一步提高牛结核病检测的特异性。     

Drug susceptibility of Brazilian strains of Mycobacterium bovis using traditional and molecular techniques

Transmission of Mycobacterium bovis from cattle to humans has been reported and can cause tuberculosis (Tb) and a problem in certain risk populations. Therefore, knowledge of resistance of M. bovis towards antibiotics used for therapy of human Tb could help avoiding cure delay and treatment cost increase when dealing with drug resistant organisms. We therefore evaluated the susceptibility of M. bovis isolates towards streptomycin, isoniazide, rifampicin, ethambutol, and ethionamide, the first line antibiotics for human Tb. Therefore, 185 clinical samples from cattle with clinical signs of tuberculosis were processed and submitted to culturing and bacterial isolates to identification and drug susceptibility testing using the proportion method. Among 89 mycobacterial strains, 65 were identified as M. bovis and none were resistant to any of the antibiotics used. Confirmation of present results by future studies, enrolling a large number of isolates and designed to properly represent Brazilian regions, may favor the idea of using isoniazide preventive therapy as part of a Tb control strategy in special situations. Also, nucleic acids from bacterial isolates were submitted to rifoligotyping, a recently described reverse hybridization assay for detection of mutations causing resistance towards rifampicin. Concordance between the conventional and the molecular test was 100%, demonstrating the use of such methodology for rapid evaluation of drug susceptibility in M. bovis.     

Inhibition of Fungal Growth in the Cultural Isolation of Mycobacteria

Antifungal antibiotics were compared to determine their usefulness in primary mycobacterial cultures. Amphotericin B was found to be more effective in preventing fungal growth from bovine fecal specimens than were cycloheximide, nystatin, and tetracycline. Amphotericin B did not affect the growth rate of the following Mycobacterium species: M. avium, M. bovis, M. intracellulare, M. paratuberculosis, M. phlei, or M. tuberculosis, but it inhibited the growth of M. fortuitum. There was no observable effect on numbers of colonies of M. paratuberculosis on primary isolation from fecal specimens. It is recommended that, for the primary isolation of pathogenic mycobacteria from specimens likely to contain fungi, the inoculum should be pretreated with benzalkonium chloride, followed by mixing with amphotericin B or inoculation onto media containing amphotericin B.     

A novel simple one-step single-tube RT-duplex PCR method with an internal control for detection of bovine viral diarrhoea virus in bulk milk, blood, and follicular fluid samples.

A simple one-step single-tube RT-PCR method was developed for detection of bovine viral diarrhea virus (BVDV) in bulk milk, blood and follicular fluid samples. A set of universal primers (UTR DL1/4) was designed for RT-PCR to detect BVDV type I and II viruses simultaneously and was tested for efficacy in comparison to published primers for two type strains, 42 field isolates, and 95 diagnostic samples. The sensitivity (100%) and specificity (96.2%) of the RT-PCR assay, with the universal primers for 95 diagnostic samples, were equal to those of virus isolation. An internal control targeting a bovine actin gene was also included in the same reaction tube to monitor RNA preparation and RT-PCR procedure. A total of 632 specimens (378 bulk milk, 140 blood, and 112 follicular samples) were tested in the year 2000 by the RT-duplex PCR assay in parallel with virus isolation. The one-step single-tube RT-duplex PCR with the universal primers UTR DL1/4 was sensitive, specific, less complicated and cost effective for detection of BVDV in various types of specimens.     

Non tuberculous mycobacteria (NTM) in patients with underlying diseases: results obtained by using polymerase chain reaction-restriction enzyme analysis between 1997-2002

In this study, we aimed to evaluate the frequency of non-tuberculous mycobacteria (NTM) isolated from clinical specimens using Polymerase Chain Reaction-Restriction Enzyme Analysis (PCR-REA) and to investigate the patients who had clinically significant NTM infections in our hospital through the five year period from May 1997 to June 2002. A total of 364 mycobacterial strains isolated from clinical specimens which gave positive growth index in the BACTEC 460 radiometric system in Hacettepe University Hospital Clinical Microbiology Laboratory were evaluated by PCR-REA and clinical data were obtained from the patient records. Three hundred and one of the strains (82.7%) were identified as Mycobacterium tuberculosis and 63 (17.3%) were identified as nontuberculous mycobacteria. Seven (11.1%) of 63 NTM patients were regarded as having clinical mycobacteriosis. Chronic obstructive pulmonary disease and other pre-existing lung diseases were seen in 39 (61.9%) of the patients, 11 (17.5%) of'the patients had chronic renal failure. Four (6.3%) and 9 (14.3%) of them had AIDS and carcinomas, respectively. PCR-REA was found to be a reliable method for typing of our mycobacterial isolates to the species level. These data may shed light on the epidemiology of the mycobacterial species and help to select a proper treatment regimen.     

Feasibility of using coyotes (Canis latrans) as sentinels for bovine mycobacteriosis (Mycobacterium bovis) infection in wild cervids in and around Riding Mountain National Park, Manitoba, Canada

Elk (Cervus elaphus manitobensis) and white-tailed deer (Odocoileus virginianus) in the Riding Mountain National Park (RMNP) region of southwestern Manitoba have been identified as a likely wildlife reservoir of Mycobacterium bovis, the causative agent of bovine mycobacteriosis in livestock. The feasibility of using coyotes (Canis latrans) collected from trappers as a sentinel species was investigated. Retropharyngeal, mesenteric, and colonic lymph nodes and tonsils collected at necropsy from 82 coyotes were examined by bacterial culture, polymerase chain reaction (PCR), and acid-fast histopathology. Mycobacterium bovis was not identified in any animal by culture or PCR although Mycobacterium avium species were isolated. A single acid-fast organism was identified on histopathologic examination of one animal. Based on the methods used in this study, trapper-caught coyotes do not appear to be a sensitive sentinel species of M. bovis infection in cervids in and around RMNP.     

Spoligotyping and variable number tandem repeat analysis of Mycobacterium bovis isolates from cattle in Brazil

We performed spoligotyping and 12-mycobacterial interspersed repetitive unit-variable number tandem repeats (MIRU-VNTRs) typing to characterise Mycobacterium bovis isolates collected from tissue samples of bovines with lesions suggestive for tuberculosis during slaughter inspection procedures in abattoirs in Brazil. High-quality genotypes were obtained with both procedures for 61 isolates that were obtained from 185 bovine tissue samples and all of these isolates were identified as M. bovis by conventional identification procedures. On the basis of the spoligotyping, 53 isolates were grouped into nine clusters and the remaining eight isolates were unique types, resulting in 17 spoligotypes. The majority of the Brazilian M. bovis isolates displayed spoligotype patterns that have been previously observed in strains isolated from cattle in other countries. MIRU-VNTR typing produced 16 distinct genotypes, with 53 isolates forming eight of the groups, and individual isolates with unique VNTR profiles forming the remaining eight groups. The allelic diversity of each VNTR locus was calculated and only two of the 12-MIRU-VNTR loci presented scores with either a moderate (0.4, MIRU16) or high (0.6, MIRU26) discriminatory index (h). Both typing methods produced similar discriminatory indexes (spoligotyping h = 0.85; MIRU-VNTR h = 0.86) and the combination of the two methods increased the h value to 0.94, resulting in 29 distinct patterns. These results confirm that spoligotyping and VNTR analysis are valuable tools for studying the molecular epidemiology of M. bovis infections in Brazil.     

The incidence of Shiga toxin-producing Escherichia coli in cattle with mastitis in Brazil

AIMS: To determine the prevalence and molecular characteristics of Shiga toxin-producing Escherichia coli (STEC) isolates from bovine mastitic milk in Brazil. METHODS AND RESULTS: A total of 2144 milk samples from dairy cattle showing mastitis were screened for the presence of E. coli. A total of 182 E. coli isolates were selected and examined. All were subjected to dot blot analysis using the CVD419 probe for the detection of the enterohaemolysin (hly) gene, and to a multiplex PCR for the detection of stx1, stx2 and eaeA genes. STEC were isolated from 22 (12.08%) milk samples. All the STEC isolates were tested for sensibility to 10 antimicrobials; the resistances most commonly observed were to cephalothin (86.3%), tetracycline (63.6%) and doxycycline (63.6%). CONCLUSION: STEC isolates were found in bovine mastitic milk in Brazil. SIGNIFICANCE AND IMPACT OF THE STUDY: STEC isolates from mastitic milk were potentially pathogenic for human in that they belonged to serogroups associated with diarrhoea and haemolytic-uraemic syndrome, some of them were stx2, eaeA and hly positive.     

Antibodies to Mycobacterium bovis in wild carnivores from Doñana National Park (Spain)

We conducted a retrospective serologic survey for antibodies against the MPB70 protein of Mycobacterium bovis in wild carnivores from Do?ana National Park (southwestern Spain). Serum samples from 118 red foxes (Vulpes vulpes), 39 Iberian lynx (Lynx pardinus), 31 Eurasian badgers (Meles meles), five Egyptian mongoose (Herpestes ichneumon), four European genet (Genetta genetta), and one Eurasian otter (Lutra lutra) were analyzed using an indirect competitive enzyme-linked immunoassay. Antibodies against the MPB70 protein of M. bovis were detected in seven badgers, five foxes, and one lynx. The frequency of positive animals was significantly higher in badger (23%) than in lynx (3%) and fox (4%). Antibodies were not detected in other species. Annual antibody frequency peaked at 38% in badgers and 11% for red fox. These species may contribute to persistence of bovine tuberculosis in Do?ana.     

Antimicrobial susceptibility of coagulase-negative staphylococci isolated from bovine mastitis between 2003 and 2008 in Korea

A total of 1,444 coagulase-negative staphylococci (CNS) isolates from bovine mastitic milk samples collected during 2003-2008 in Korea were identified to the species level. Of 14 species identified, S. simulans, S. haemolyticus, and S. sciuri accounted for over 60% of the isolates. All the CNS isolates were tested for susceptibility to eight antimicrobials commonly used in dairy cattle. With a few exceptions, similar resistance patterns were observed among the CNS species: penicillin and ampicillin showed the lowest activity while amikacin, cephalothin, and gentamycin were highly effective. About 39% (557/1,444) of the CNS isolates were pan-susceptible, while 12% (175/1,444) showed resistance to four or more antimicrobials tested.     

Genetic variation among Staphylococcus aureus strains from Norwegian bulk milk

Strains of Staphylococcus aureus obtained from bovine (n = 117) and caprine (n = 114) bulk milk were characterized and compared with S. aureus strains from raw-milk products (n = 27), bovine mastitis specimens (n = 9), and human blood cultures (n = 39). All isolates were typed by pulsed-field gel electrophoresis (PFGE). In addition, subsets of isolates were characterized using multilocus sequence typing (MLST), multiplex PCR (m-PCR) for genes encoding nine of the staphylococcal enterotoxins (SE), and the cloverleaf method for penicillin resistance. A variety of genotypes were observed, and greater genetic diversity was found among bovine than caprine bulk milk isolates. Certain genotypes, with a wide geographic distribution, were common to bovine and caprine bulk milk and may represent ruminant-specialized S. aureus. Isolates with genotypes indistinguishable from those of strains from ruminant mastitis were frequently found in bulk milk, and strains with genotypes indistinguishable from those from bulk milk were observed in raw-milk products. This indicates that S. aureus from infected udders may contaminate bulk milk and, subsequently, raw-milk products. Human blood culture isolates were diverse and differed from isolates from other sources. Genotyping by PFGE, MLST, and m-PCR for SE genes largely corresponded. In general, isolates with indistinguishable PFGE banding patterns had the same SE gene profile and isolates with identical SE gene profiles were placed together in PFGE clusters. Phylogenetic analyses agreed with the division of MLST sequence types into clonal complexes, and isolates within the same clonal complex had the same SE gene profile. Furthermore, isolates within PFGE clusters generally belonged to the same clonal complex.