Genomic characterisation of the severe acute respiratory syndrome coronavirus of Amoy Gardens outbreak in Hong Kong

Severe acute respiratory syndrome (SARS) is a global health concern. In Hong Kong, two major outbreaks, one hospital based and the other in the Amoy Gardens apartments, were identified. The frequency of diarrhoea, admission to intensive care, and mortality differed significantly between the two outbreaks. We did genomic sequencing for viral isolates from five Amoy Gardens patients. The virus sequence was identical in four of these five patients. The sequence data from one hospital case and the four identical community cases had only three nucleotide differences. Alterations in the SARS coronavirus genome are unlikely to have caused the distinctive clinical features of the Amoy Gardens patients, and these results highlight the importance of non-viral genomic factors in this outbreak.

Epidemiology and cause of severe acute respiratory syndrome (SARS) in Guangdong, People's Republic of China, in February, 2003

BACKGROUND

An epidemic of severe acute respiratory syndrome (SARS) has been associated with an outbreak of atypical pneumonia originating in Guangdong Province, People's Republic of China. We aimed to identify the causative agent in the Guangdong outbreak and describe the emergence and spread of the disease within the province.

METHODS

We analysed epidemiological information and collected serum and nasopharyngeal aspirates from patients with SARS in Guangdong in mid-February, 2003. We did virus isolation, serological tests, and molecular assays to identify the causative agent.

FINDINGS

SARS had been circulating in other cities of Guangdong Province for about 2 months before causing a major outbreak in Guangzhou, the province's capital. A novel coronavirus, SARS coronavirus (CoV), was isolated from specimens from three patients with SARS. Viral antigens were also directly detected in nasopharyngeal aspirates from these patients. 48 of 55 (87%) patients had antibodies to SARS CoV in their convalescent sera. Genetic analysis showed that the SARS CoV isolates from Guangzhou shared the same origin with those in other countries, and had a phylogenetic pathway that matched the spread of SARS to the other parts of the world.

INTERPRETATION

SARS CoV is the infectious agent responsible for the epidemic outbreak of SARS in Guangdong. The virus isolated from patients in Guangdong is the prototype of the SARS CoV in other regions and countries.

Isolation and characterization of viruses related to the SARS coronavirus from animals in southern China

A novel coronavirus (SCoV) is the etiological agent of severe acute respiratory syndrome (SARS). SCoV-like viruses were isolated from Himalayan palm civets found in a live-animal market in Guangdong, China. Evidence of virus infection was also detected in other animals (including a raccoon dog, Nyctereutes procyonoides) and in humans working at the same market. All the animal isolates retain a 29-nucleotide sequence that is not found in most human isolates. The detection of SCoV-like viruses in small, live wild mammals in a retail market indicates a route of interspecies transmission, although the natural reservoir is not known.

Nontuberculous mycobacterial infections in Chinese hematopoietic stem cell transplantation recipients

Between 1995 and 2002, nine cases of nontuberculous mycobacterium (NTM) were isolated from 462 allogeneic stem cell transplant (SCT) recipients (1.9%), and none from 139 autologous cases. They included three cases each of Mycobacterium fortuitum and M. chelonae, and single cases of M. scrofalaceum, M. gordonnae and M. avium complex. Seven cases were respiratory, including five cases requiring treatment, and two involved infected catheters and vascular conduits. Compared with nine cases of mycobacterium tuberculosis (MTB) isolated in the same period, NTM isolation occurred later after HSCT and involved more unrelated donors. Important risk factors for NTM infection included significant aGVHD (P=0.043), leukemia relapse (P=0.022), MUD and mismatch SCT (P<0.001) and existence of BO (P<0.001). Coinfection with aspergillus was common. Invasive NTM disease required prolonged antimicrobial treatment in five cases due to M. fortuitum and M. chelonae. With better MTB prophylaxis, intensive immunosuppression and better awareness, NTM has become an emerging threat in oriental allogeneic HSCT recipients. The cutoff between colonization and infection, and the threshold for starting treatment is unclear. NTM isolation is a marker for severe immunosuppression and poor prognosis. When there is doubt over species identity or extent of infection, broad-spectrum cover may be prudent.

Risk factors for development of paradoxical response during antituberculosis therapy in HIV-negative patients

The risk factors for development of paradoxical response were studied in a cohort of 104 patients with culture-documented Mycobacterium tuberculosis infection. Paradoxical deterioration occurred in 16 (15.4%) patients (case group) during antituberculosis therapy, involving lungs and pleura (n=4), spine and paraspinal tissue (n=5), intracranium (n=3), peritoneum (n=2), bone and joint (n=1), and lymph node (n=1). The median time from commencement of treatment to paradoxical deterioration was 56 days (range, 20-109 days). Compared with 53 patients without clinical deterioration after antituberculosis therapy (control group), patients with paradoxical response were more likely to have extrapulmonary involvement (62.5% vs. 17.0%; P<0.05) at initial diagnosis, to have lower baseline lymphocyte counts (672+/-315 cells/microl vs. 1,328+/-467 cells/microl; P<0.001), and to exhibit a greater surge in lymphocyte counts (627+/-465 cells/microl vs. 225+/-216 cells/microl; P<0.05) during paradoxical response. Further studies on lymphocyte subsets and cytokine levels would be useful in understanding the exact immunological mechanisms involved in immunorestitution.

Gemella bacteraemia characterised by 16S ribosomal RNA gene sequencing

AIMS

To define epidemiology, clinical disease, and outcome of gemella bacteraemia by 16S rRNA gene sequencing. To examine the usefulness of the Vitek, API, and ATB systems in identifying two gemella species.

METHODS

All alpha haemolytic streptococci other than Streptococcus pneumoniae isolated from blood cultures during a six year period were identified by conventional biochemical methods, the Vitek system, and the API system. 16S rRNA gene sequencing was performed on all isolates identified by both kits as gemella with >or= 95% confidence or by either kit as any bacterial species with < 95% confidence. The ATB expression system was used to identify the two isolates that were defined as gemella species by 16S rRNA gene sequencing.

RESULTS

Of the 302 alpha haemolytic streptococci other than S pneumoniae isolated, one was identified as Gemella morbillorum, and another as Gemella haemolysans by 16S rRNA gene sequencing. The patient with monomicrobial G morbillorum bacteraemia was a 66 year old man with community acquired infective endocarditis with septic thromboemboli. The patient with G haemolysans bacteraemia was a 41 year old woman with hospital acquired polymicrobial bacteraemia during the neutropenic period of an autologous bone marrow transplant for non-Hodgkin's lymphoma, the first case of its kind in the English literature. The API and ATB expression systems only identified the second strain as G haemolysans at 94% and 99% confidence, respectively, whereas the Vitek system identified none of the two strains correctly at > 70% confidence.

CONCLUSIONS

Gemella bacteraemia is uncommon. 16S rRNA gene sequencing is the method of choice for identification of gemella and gemella-like isolates.

The complete genome sequence of severe acute respiratory syndrome coronavirus strain HKU-39849 (HK-39)

The complete genomic nucleotide sequence (29.7kb) of a Hong Kong severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) strain HK-39 is determined. Phylogenetic analysis of the genomic sequence reveals it to be a distinct member of the Coronaviridae family. 5' RACE assay confirms the presence of at least six subgenomic transcripts all containing the predicted intergenic sequences. Five open reading frames (ORFs), namely ORF1a, 1b, S, M, and N, are found to be homologues to other CoV members, and three more unknown ORFs (X1, X2, and X3) are unparalleled in all other known CoV species. Optimal alignment and computer analysis of the homologous ORFs has predicted the characteristic structural and functional domains on the putative genes. The overall nucleotides conservation of the homologous ORFs is low (<5%) compared with other known CoVs, implying that HK-39 is a newly emergent SARS-CoV phylogenetically distant from other known members. SimPlot analysis supports this finding, and also suggests that this novel virus is not a product of a recent recombinant from any of the known characterized CoVs. Together, these results confirm that HK-39 is a novel and distinct member of the Coronaviridae family, with unknown origin. The completion of the genomic sequence of the virus will assist in tracing its origin.

Characterization of H9 subtype influenza viruses from the ducks of southern China: a candidate for the next influenza pandemic in humans?

A current view of the emergence of pandemic influenza viruses envisages a gene flow from the aquatic avian reservoir to humans via reassortment in pigs, the hypothetical "mixing vessel." Understanding arising from recent H5N1 influenza outbreaks in Hong Kong since 1997 and the isolation of avian H9N2 virus from humans raises alternative options for the emergence of a new pandemic virus. Here we report that H9N2 influenza viruses established in terrestrial poultry in southern China are transmitted back to domestic ducks, in which the viruses generate multiple reassortants. These novel H9N2 viruses are double or even triple reassortants that have amino acid signatures in their hemagglutinin, indicating their potential to directly infect humans. Some of them contain gene segments that are closely related to those of A/Hong Kong/156/97 (H5N1/97, H5N1) or A/Quail/Hong Kong/G1/97 (G1-like, H9N2). More importantly, some of their internal genes are closely related to those of novel H5N1 viruses isolated during the outbreak in Hong Kong in 2001. This study reveals a two-way transmission of influenza virus between terrestrial and aquatic birds that facilitates the generation of novel reassortant H9N2 influenza viruses. Such reassortants may directly or indirectly play a role in the emergence of the next pandemic virus.

Clinical progression and viral load in a community outbreak of coronavirus-associated SARS pneumonia: a prospective study

BACKGROUND

We investigated the temporal progression of the clinical, radiological, and virological changes in a community outbreak of severe acute respiratory syndrome (SARS).

METHODS

We followed up 75 patients for 3 weeks managed with a standard treatment protocol of ribavirin and corticosteroids, and assessed the pattern of clinical disease, viral load, risk factors for poor clinical outcome, and the usefulness of virological diagnostic methods.

FINDINGS

Fever and pneumonia initially improved but 64 (85%) patients developed recurrent fever after a mean of 8.9 (SD 3.1) days, 55 (73%) had watery diarrhoea after 7.5 (2.3) days, 60 (80%) had radiological worsening after 7.4 (2.2) days, and respiratory symptoms worsened in 34 (45%) after 8.6 (3.0) days. In 34 (45%) patients, improvement of initial pulmonary lesions was associated with appearance of new radiological lesions at other sites. Nine (12%) patients developed spontaneous pneumomediastinum and 15 (20%) developed acute respiratory distress syndrome (ARDS) in week 3. Quantitative reverse-transcriptase (RT) PCR of nasopharyngeal aspirates in 14 patients (four with ARDS) showed peak viral load at day 10, and at day 15 a load lower than at admission. Age and chronic hepatitis B virus infection treated with lamivudine were independent significant risk factors for progression to ARDS (p=0.001). SARS-associated coronavirus in faeces was seen on RT-PCR in 65 (97%) of 67 patients at day 14. The mean time to seroconversion was 20 days.

INTERPRETATION

The consistent clinical progression, shifting radiological infiltrates, and an inverted V viral-load profile suggest that worsening in week 2 is unrelated to uncontrolled viral replication but may be related to immunopathological damage.

Development of a standard treatment protocol for severe acute respiratory syndrome

A series of 31 patients with probable SARS, diagnosed from WHO criteria, were treated according to a treatment protocol consisting of antibacterials and a combination of ribavirin and methylprednisolone. Through experience with the first 11 patients, we were able to finalise standard dose regimens, including pulsed methylprednisolone. One patient recovered on antibacterial treatment alone, 17 showed rapid and sustained responses, and 13 achieved improvement with step-up or pulsed methylprednisolone. Four patients required short periods of non-invasive ventilation. No patient required intubation or mechanical ventilation. There was no mortality or treatment morbidity in this series.

Peripartum tuberculosis as a form of immunorestitution disease

The aim of this study was to assess the clinical spectrum of peripartum tuberculosis from the perspective of immunorestitution disease. Of 29 patients with peripartum tuberculosis, 27 (93.1%) had extrapulmonary tuberculosis, 20 (69%) of whom were affected in the central nervous system. Twenty-two (75.9%) patients had no clinical features suggestive of tuberculosis during pregnancy. The median time from delivery to the onset of immunorestitution was 4 days, but treatment with anti-tuberculous therapy was delayed for a median time of 27 days after the onset of symptoms. Despite therapy, 11 (38%) patients died and 4 (13.8%) had residual functional deficits. Peripartum tuberculosis is an important differential diagnosis of postpartum fever (of unknown origin) without localized signs.

Coronavirus as a possible cause of severe acute respiratory syndrome

BACKGROUND

An outbreak of severe acute respiratory syndrome (SARS) has been reported in Hong Kong. We investigated the viral cause and clinical presentation among 50 patients.

METHODS

We analysed case notes and microbiological findings for 50 patients with SARS, representing more than five separate epidemiologically linked transmission clusters. We defined the clinical presentation and risk factors associated with severe disease and investigated the causal agents by chest radiography and laboratory testing of nasopharyngeal aspirates and sera samples. We compared the laboratory findings with those submitted for microbiological investigation of other diseases from patients whose identity was masked.

FINDINGS

Patients' age ranged from 23 to 74 years. Fever, chills, myalgia, and cough were the most frequent complaints. When compared with chest radiographic changes, respiratory symptoms and auscultatory findings were disproportionally mild. Patients who were household contacts of other infected people and had older age, lymphopenia, and liver dysfunction were associated with severe disease. A virus belonging to the family Coronaviridae was isolated from two patients. By use of serological and reverse-transcriptase PCR specific for this virus, 45 of 50 patients with SARS, but no controls, had evidence of infection with this virus.

INTERPRETATION

A coronavirus was isolated from patients with SARS that might be the primary agent associated with this disease. Serological and molecular tests specific for the virus permitted a definitive laboratory diagnosis to be made and allowed further investigation to define whether other cofactors play a part in disease progression.

Staphylococcus aureus subcutaneous abscess complicating acupuncture: need for implementation of proper infection control guidelines

We report a case of Staphylococcus aureus subcutaneous abscess centered over the Jizhong acupuncture point (DU 6) which lies along the Du (Back midline) meridian after acupuncture at the corresponding acupuncture point for low back pain. The patient recovered after surgical debridement and drainage and 5 weeks of cloxacillin therapy. Among the 16 anecdotal case reports of pyogenic bacterial infections complicating acupuncture described in the English literature (MEDLINE Search 1996-2002), S. aureus was documented to be the causative agent in 9 (56%). Three patients had septic arthritis, 2 had chronic osteomyelitis, 2 had abscess formation, 1 had chondritis, and 1 had infective endocarditis. Five patients had S. aureus bacteremia. All patients who recovered required prolonged antibiotic treatment of 5-6 weeks, and 6 required drainage and/or debridement. Overall, 3 patients (30%) died. S. aureus causes significant morbidity and mortality in patients who receive acupuncture treatment. More resources should be spent on implementation of proper infection control guidelines, as the money lost due to prolonged hospitalization and medication would far exceed that used for implementation.

Pseudobacteraemia in a patient with neutropenic fever caused by a novel paenibacillus species: Paenibacillus hongkongensis sp. nov

AIMS

To characterise a strain of Gram negative aerobic straight or slightly curved rods (HKU3) isolated from the blood culture of a 9 year old Chinese boy with neutropenic fever and pseudobacteraemia.

METHODS

The isolate was phenotypically investigated by standard biochemical methods using conventional biochemical tests, scanning electron microscopy, and transmission electron microscopy. Genotypically, the 16S rRNA gene of the bacterium was amplified by the polymerase chain reaction (PCR) and sequenced. The sequence of the PCR product was compared with known 16S rRNA gene sequences in the Genbank by multiple sequence alignment. The G + C content was determined by thermal denaturation. A phylogenetic tree was constructed by the PileUp method.

RESULTS

The cells of the bacterial strain were aerobic, sporulating, Gram negative straight or slight curved rods. The bacterium grew on horse blood agar as non-haemolytic, grey colonies of 1 mm in diameter after 24 hours of incubation at 37 degrees C in ambient air. No enhancement of growth was seen in 5% CO(2). It grew at 50 degrees C as pinpoint colonies after 72 hours of incubation, but did not grow at 65 degrees C or on MacConkey agar. It was non-motile. It produced catalase (weakly positive) and cytochrome oxidase. It reduced nitrate, produced beta galactosidase, hydrolysed esculin, and utilised sodium acetate. A scanning electron micrograph of the bacterium showed straight or slightly curved rods. A transmission electron micrograph of the cell wall of the bacterium revealed multiple electron dense layers, including the outer membrane, middle murein layer, and inner cytoplasmic membrane, compatible with its Gram smear appearance. 16S rRNA gene sequencing showed that there were 7.7%, 8.0%, 8.2%, and 8.6% differences between the 16S rRNA gene sequence of the bacterium and those of Paenibacillus macerans, Paenibacillus borealis, Bacillus ehimensis, and Paenibacillus amylolyticus, respectively. The mean (SD) G + C content of the bacterium was 47.6 (2.1) mol%. Phylogenetically, it belongs to the genus paenibacillus (previously called group 3 bacillus).

CONCLUSIONS

A bacterium that exhibited phenotypic and genotypic characteristics that are very different from closely related members of paenibacillus was the cause of pseudobacteraemia in a patient with neutropenic fever. A new species, Paenibacillus hongkongensis sp. nov. is proposed, for which HKU3 is the type strain.

Surgical complications and outcome of pediatric liver transplantation in Hong Kong

PURPOSE

The aim of this study was to analyze the early and late results of pediatric liver transplantation, with particular reference to complications that required surgical or radiologic intervention.

METHODS

The records and code sheets of children who underwent liver transplantation in the authors' institution between September 1993 and December 2001 were reviewed.

RESULTS

Twenty-nine children (16 boys and 13 girls) underwent 31 liver transplantations (23 living donor, 8 cadaveric donor) during the study period. The ages of the children ranged from 4 months to 132 months (median, 16 months). Eighteen children had complications that required surgical or radiologic interventional procedures. Complications included, among others, hepatic vein thrombosis (n = 1, 3%), hepatic vein stenosis (n = 2, 7%), portal vein thrombosis (n = 2, 7%), biliary stricture (n = 3, 10%), bile leakage (n = 2, 7%), hepatic artery pseudoaneurysm (n = 1, 3%), jejuno-jejunostomy leakage (n = 1, 3%), graft hepatitis (n = 1, 3%), and posttransplant lymphoproliferative disorder (n = 2, 7%). In addition, 6 children (21%) suffered from intraabdominal bleeding from a variety of causes. After appropriate interventions, at a median follow-up of 38 months (range, 1 to 96 months), patient and graft survival rates were 79% and 74%, respectively. The retransplantation rate was only 7%. There was no incidence of hepatic artery thrombosis. All living donors remain alive and well.

CONCLUSIONS

Complications are inevitable in pediatric liver transplantation. However, with timely recognition and active intervention, a good outcome can be achieved.

Clinical spectrum of paradoxical deterioration during antituberculosis therapy in non-HIV-infected patients

Paradoxical deterioration during antituberculosis therapy, defined as the clinical or radiological worsening of pre-existing tuberculous lesions or the development of new lesions in a patient who initially improves, remains a diagnostic dilemma. Although different clinical presentations of paradoxical response have been described, a systematic analysis of the entity in non-HIV-infected patients is lacking. Reported here are two cases of paradoxical deterioration in which sequential changes in lymphocyte counts and tuberculin skin test results are emphasized. In addition, 120 episodes of paradoxical response after antituberculosis treatment were reviewed. Of the total 122 episodes, 101 (82.8%) were associated with extrapulmonary tuberculosis. The median time from commencement of treatment to paradoxical deterioration was 60 days. The median time to onset of central nervous system manifestations (63 days) was longer than the time to onset of manifestations at other sites (56 days) ( P=0.02). Development of new lesions in anatomical sites other than those observed at initial presentation was observed in 31 (25.4%) episodes. A surge in the lymphocyte count, accompanied by an exaggerated tuberculin skin reaction, was observed in our patients during the paradoxical deterioration, analogous to the findings in HIV-positive patients. Treatment of the paradoxical response included surgical intervention (60.7%) and administration of steroids (39.3%). The use of steroids appeared to be safe in this series, as 95% of the Mycobacterium tuberculosis isolates were susceptible to first-line antituberculosis therapy.

Characterization of a laboratory-generated variant of BPS beta-lactamase from Burkholderia pseudomallei that hydrolyses ceftazidime

Burkholderia pseudomallei produces an Ambler class A beta-lactamase, known as BPS-1. The beta-lactamase gene from a laboratory-derived, ceftazidime-resistant strain of B. pseudomallei (LH-1-2) was cloned and expressed in Escherichia coli. The beta-lactamase, named BPS-1m, had an identical isoelectric focusing point (pI 7.7) to that of BPS-1, but differed in having a stronger hydrolytic activity against ceftazidime. Susceptibility testing showed that BPS-1m when expressed in E. coli conferred resistance to ceftazidime (MIC >or= 32 mg/L). The amino acid sequence of BPS-1m differed from that of BPS-1 by a Pro-to-Ser change at position 167 in the omega loop.

Ten-year experience with liver transplantation at Queen Mary Hospital: retrospective study

OBJECTIVE

To report the experience with liver transplantation at the Queen Mary Hospital from 1991 to 2000.

DESIGN

Retrospective study.

SETTING

Liver transplant centre of a University teaching hospital, Hong Kong.

PATIENTS

One hundred and forty-eight patients (127 adults and 21 children) who underwent a total of 155 liver transplants using 75 cadaver grafts (full-size, 67; reduced-size, 5; split, 3) and 80 living donor grafts (left lateral segment, 15; left lobe, 6; right lobe, 59) from October 1991 to December 2000 were reviewed.

MAIN OUTCOME MEASURES

Graft and patient survival rate.

RESULTS

The most common disease indications for liver transplantation were chronic hepatitis B-related liver disease (n=74) in adults and biliary atresia (n=14) in children. Eighteen patients had hepatocellular carcinoma. Forty-eight (31%) liver transplants (three ABO-incompatible) were performed in high-urgency situations for patients requiring intensive care. The proportion of living donor liver transplants was 47.7% in adults and 73.9% in children. The overall 1-year and 5-year patient survival rates were 82% and 77%, respectively. The survival of high-risk recipients, such as those with fulminant hepatic failure (80%), chronic hepatitis B (81%), or hepatocellular carcinoma (94%), was not inferior to that of other patients.

CONCLUSION

Over the last decade, the promotion of (cadaver) organ donation through public education coupled with innovative techniques in living donor liver transplantation have enabled a liver transplantation programme to be established in Hong Kong with gratifying results.

Tuberculosis in blood and marrow transplant recipients

Although one third of the world's population is infected with tuberculosis (TB), TB in blood and marrow transplant (BMT) recipients is relatively less well studied, as the incidence of TB is relatively low in developed countries with BMT units. Since the report of the first two cases in 1983, 52 cases of TB complicating BMT have been reported in the English literature from BMT centers in ten different countries. Not unexpectedly, the two largest series were reported from areas with a high incidence of TB in the general population, with about 45 cases per 10(5) inhabitants per year in Spain and about 100 cases per 10(5) inhabitants per year in Hong Kong respectively. The overall frequency of occurrence of TB in BMT recipients was 0.4% (52 cases among 13 881 BMT recipients), with a male:female ratio of 11:9 and median age of 33 (range 7-57). The incidence of TB in the general population is a major predictor of a higher frequency of occurrence in BMT recipients. Moreover, allogeneic transplantation, graft-versus-host disease, and total body irradiation were found to be risk factors associated with TB. Among the 48 cases in whom the time of manifestation were reported, only one case manifested during the neutropenic period (day 11). On the other hand, 11 cases (23%) manifest after engraftment but before day 100, and 36 (75%) manifest after day 100. The most important aspect towards making the diagnosis is a high index of suspicion, as TB occurred in relatively low frequencies especially in developed countries, and the clinical patterns usually mimic other more common infectious and non-infectious complications after BMT. As the incidence of drug resistant TB is increasing, we prefer to treat our patients for at least one year (as compared with six months in immunocompetent hosts) with four drugs in the first six months and two or three drugs for another six months. In those patients who could not tolerate oral medication, we used an intravenous regimen of rifampicin, ciprofloxacin, and amikacin until oral therapy could be instituted. The absence of relapse after termination of treatment in our patients suggested that secondary prophylaxis would not be necessary as long as immune function has been restored. With the rising incidence of TB in countries that previously enjoyed a very low prevalence of TB, attributed to the growing population of HIV-infected subjects with TB, and the changing patterns of population migration, it is important to bear a high index of suspicion of Mycobacterium tuberculosis as a pathogen in BMT recipients.

Identification by 16S ribosomal RNA gene sequencing of Arcobacter butzleri bacteraemia in a patient with acute gangrenous appendicitis

AIMS

To identify a strain of Gram negative facultative anaerobic curved bacillus, concomitantly isolated with Escherichia coli and Streptococcus milleri, from the blood culture of a 69 year old woman with acute gangrenous appendicitis. The literature on arcobacter bacteraemia and arcobacter infections associated with appendicitis was reviewed.

METHODS

The isolate was phenotypically investigated by standard biochemical methods using conventional biochemical tests. Genotypically, the 16S ribosomal RNA (rRNA) gene of the bacterium was amplified by the polymerase chain reaction (PCR) and sequenced. The sequence of the PCR product was compared with known 16S rRNA gene sequences in the GenBank by multiple sequence alignment. Literature review was performed by MEDLINE search (1966-2000).

RESULTS

The bacterium grew on blood agar, chocolate agar, and MacConkey agar to sizes of 1 mm in diameter after 24 hours of incubation at 37 degrees C in 5% CO2. It grew at 15 degrees C, 25 degrees C, and 37 degrees C; it also grew in a microaerophilic environment, and was cytochrome oxidase positive and motile, typically a member of the genus arcobacter. Furthermore, phenotypic testing showed that the biochemical profile of the isolate did not fit into the pattern of any of the known arcobacter species. 16S rRNA gene sequencing showed one to two base differences between the isolate and A butzleri, but 35 to 39 base differences between the isolate and A cryaerophilus, indicating that the isolate was a strain of A butzleri. Only three cases of arcobacter bacteraemia with detailed clinical characteristics were found in the English literature. The sources of the arcobacter species in the three cases were largely unknown, although the gastrointestinal tract is probably the portal of entry of the A butzleri isolated from the present case because the two concomitant isolates (E coli and S milleri) in the blood culture were common flora of the gastrointestinal tract. In addition, A butzleri has previously been isolated from the abdominal contents or peritoneal fluid of three patients with acute appendicitis.

CONCLUSIONS

16S rRNA gene sequencing was useful in the identification of the strain of A butzleri isolated from the blood culture of a patient with acute gangrenous appendicitis. Arcobacter bacteraemia is rare. Further studies using selective medium for the delineation of the association between A butzleri and acute appendicitis are warranted.

Perianal abscess caused by Propionibacterium avidum in a cirrhotic patient

We describe the first case of community-acquired Propionibacterium avidum subcutaneous tissue infection in a cirrhotic patient. A 70-year-old Chinese male with a 2-year history of hepatitis B virus-induced chronic liver failure and hemorrhoidectomy 17 months previously presented with a painful left buttock abscess, which was culture positive for P. avidum. Being a normal flora of skin with low pathogenicity, there have been only 3 case reports on P. avidum infection, all associated with surgical intervention within 2 to 6 weeks before the onset of P. avidum infection. We hereby review the literature on P. avidum summarizing