A total of 182 Salmonella enterica serotype Typhi isolated from three hospitals in Hong Kong from 1986 to 1992 were tested for their susceptibility to 21 antimicrobial agents. Four percent or less were resistant to chloramphenicol, ampicillin, some of the cephalosporins, nalidixic acid, tetracycline and trimethoprim and 6% to 1024 mg/l sulfamethoxazole. All were susceptible to the aminoglycosides and the 4-quinolones. Nineteen isolates were resistant to at least 1, and up to 9, antibiotics. Of 8 chloramphenicolor multiply-resistant isolates studied, only 3 could transfer their resistances while resistance of one could only be mobilized. Four of 5 ampicillin-resistant strains produced a beta-lactamase of pI 5.5. Antibiotic resistances were mediated by plasmids of 106, 116 or 221 kb of incompatibility groups H, I1 and K. Three resistant isolates did not harbour any plasmid. A total of 43 (24%) S. Typhi harboured plasmids ranging in size from 4.3 to 221 kb. Plasmids of 106 kb and 8.5 kb were found in 17 and 10 isolates, respectively. Restriction enzyme digestion of these two plasmids showed that each could be differentiated into 3 types. Of 89 isolates that were phage typed, 38% were untypable, while 17% and 12% were of phage types E1 and A, respectively, and the rest belonged to 17 other types.

Jupiter's moon Io is known to host active volcanoes. In February and March 2007, the New Horizons spacecraft obtained a global snapshot of Io's volcanism. A 350-kilometer-high volcanic plume was seen to emanate from the Tvashtar volcano (62 degrees N, 122 degrees W), and its motion was observed. The plume's morphology and dynamics support nonballistic models of large Io plumes and also suggest that most visible plume particles condensed within the plume rather than being ejected from the source. In images taken in Jupiter eclipse, nonthermal visible-wavelength emission was seen from individual volcanoes near Io's sub-Jupiter and anti-Jupiter points. Near-infrared emission from the brightest volcanoes indicates minimum magma temperatures in the 1150- to 1335-kelvin range, consistent with basaltic composition.

BACKGROUND: Human infection with an avian influenza A virus (subtype H5N1) was reported recently in Hong Kong. We describe the clinical presentation of the first 12 patients and options for rapid viral diagnosis. METHODS: Case notes of 12 patients with virus-culture-confirmed influenza A H5N1 infection were analysed. The clinical presentation and risk factors associated with severe disease were defined and the results of methods for rapid virus diagnosis were compared. FINDINGS: Patients ranged from 1 to 60 years of age. Clinical presentation was that of an influenza-like illness with evidence of pneumonia in seven patients. All seven patients older than 13 years had severe disease (four deaths), whereas children 5 years or younger had mild symptoms with the exception of one who died with Reye's syndrome associated with intake of aspirin. Gastrointestinal manifestations, raised liver enzymes, renal failure unrelated to rhabdomyolysis, and pancytopenia were unusually prominent. Factors associated with severe disease included older age, delay in hospitalisation, lower-respiratory-tract involvement, and a low total peripheral white blood cell count or lymphopenia at admission. An H5-specific reverse-transcription PCR assay (RT-PCR) was useful for rapid detection of virus directly in respiratory specimens. A commercially available enzyme immunoassay was more sensitive than direct immunofluorescence for rapid viral diagnosis. Direct immunofluorescence with an H5-specific monoclonal antibody pool was useful for rapid exclusion of H5-subtype infection. INTERPRETATION: Avian Influenza A H5N1 virus causes human influenza-like illness with a high rate of complications in adults admitted to hospital. Rapid H5-subtype-specific laboratory diagnosis can be made by RT-PCR applied directly to clinical specimens.

Eighteen cases of human influenza A H5N1 infection were identified in Hong Kong from May to December 1997. Two of the six fatal cases had undergone a full post-mortem which showed reactive hemophagocytic syndrome as the most prominent feature. Other findings included organizing diffuse alveolar damage with interstitial fibrosis, extensive hepatic central lobular necrosis, acute renal tubular necrosis and lymphoid depletion. Elevation of soluble interleukin-2 receptor, interleukin-6 and interferon-gamma was demonstrated in both patients, whereas secondary bacterial pneumonia was not observed. Virus detection using isolation, reverse transcription-polymerase chain reaction and immunostaining were all negative. It is postulated that in fatal human infections with this avian subtype, initial virus replication in the respiratory tract triggers hypercytokinemia complicated by the reactive hemophagocytic syndrome. These findings suggest that the pathogenesis of influenza A H5N1 infection might be different from that of the usual human subtypes H1-H3.

Randomised trials have shown that duodenal ulcers treated by H2 blockers heal faster if Helicobacter pylori is eradicated concurrently. It remains unknown whether eradication of H pylori without suppression of acid-secretion, is sufficient to allow healing. 153 patients with H pylori infection and duodenal ulcer were randomised to receive either a 1-week course of bismuth subcitrate, tetracycline, and metronidazole (76), or omeprazole for 4 weeks with the same three-drug regimen for the first week (77). Endoscopy and antral biopsies were done at entry and 4 weeks after treatment. 132 patients were suitable for analysis. Duodenal ulcers healed in 60 (92%; 95% CI 86-100%) patients taking bismuth, tetracycline, and metronidazole compared with 63 (95%; 88-100%) taking omeprazole in addition to the three other drugs. H pylori was eradicated in 61 (94%; 88-100%) who received only three drugs compared with 66 (98%; 96-100%) who received omeprazole as well. Symptoms were reduced more effectively during the first week in patients who received omeprazole (p = 0.003). We conclude that a 1-week regimen of bismuth, tetracycline, and metronidazole for patients with H pylori and duodenal ulcer eradicates the organism and heals the ulcer in most patients. Concurrent administration of omeprazole reduces ulcer pain more rapidly but has no effect on ulcer healing.

BACKGROUND. There is a strong association between infection with Helicobacter pylori and gastric ulcers that are unrelated to the use of nonsteroidal antiinflammatory medications. We studied the efficacy of antibacterial therapy without medication to suppress gastric acid for the treatment of patients with H. pylori infection and gastric ulcers unrelated to the use of nonsteroidal agents. METHODS. Patients with gastric ulcers seen on endoscopy and with H. pylori infection confirmed by smear or culture were randomly assigned to receive either a one-week course of antibacterial agents (120 mg of bismuth subcitrate, 500 mg of tetracycline, and 400 mg of metronidazole, each given orally four times a day) or a four-week course of omeprazole (20 mg orally per day). Follow-up endoscopies were performed after five and nine weeks. The patients and their physicians were aware of the treatment assignments, but the endoscopists were not. RESULTS. A total of 100 patients were randomly assigned to treatment, and 85 completed the trial. At five weeks, H. pylori had been eradicated in 41 of the 45 patients in the antibacterial-treatment group (91.1 percent; 95 percent confidence interval, 82.9 to 99.3) and in 5 of the 40 in the omeprazole group (12.5 percent; 95 percent confidence interval, 2.3 to 22.7; P < 0.001). The gastric ulcers were healed in 38 of the patients treated with antibacterial drugs (84.4 percent; 95 percent confidence interval, 73.9 to 95.0) and in 29 of those treated with omeprazole (72.5 percent; 95 percent confidence interval, 58.6 to 86.4; P = 0.28). At nine weeks, ulcer healing was confirmed in 43 of the patients receiving antibacterial therapy and in 37 of those receiving omeprazole (P = 1.0). The mean (+/- SD) duration of pain during the first week of treatment was 1.9 +/- 2.6 days in the omeprazole group, as compared with 3.6 +/- 3.0 days in the antibacterial-treatment group (P = 0.004). One year after treatment, recurrent gastric ulcers were detected in 1 of 22 patients (4.5 percent) in the antibacterial-treatment group and in 12 of 23 (52.2 percent) in the omeprazole group (P = 0.001). H. pylori was detected in the 1 patient with a recurrent ulcer who had received antibacterial treatment and in 10 of the 12 patients with recurrent ulcers who had received omeprazole. CONCLUSIONS. In patients with H. pylori infection and gastric ulcers unrelated to the use of nonsteroidal antiinflammatory drugs, one week of antibacterial therapy without acid suppression heals the ulcers as well as omeprazole and reduces the rate of their recurrence.

While most authorities agree that methicillin-resistant Staphylococcus aureus (MRSA) are as pathogenic as methicillin-sensitive strains (MSSA), some believe that MRSA are relatively avirulent opportunists, and that their importance has been exaggerated. We present evidence that Hong Kong strains of MRSA and MSSA are equally pathogenic: they have similar virulence in animal models; they are isolated in similar proportions from both deep and superficial clinical sites including blood; in patients with hospital-acquired bacteraemias mortality rates are similar when adjusted for clinical factors; and in both animals and patients with systemic MRSA infection, mortality rates are significantly reduced by vancomycin therapy. Efforts to control the spread of MRSA are justified, and in invasive sepsis early treatment with vancomycin may be life-saving.

BACKGROUND: Metronidazole is one of the most commonly used antimicrobial agents for the treatment of Helicobacter pylori infection. Resistance to metronidazole has been reported worldwide but with a wide range of prevalence. We started using the classical triple therapy (bismuth, tetracycline, and metronidazole) for H. pylori infection in 1991 but recently have experienced a decline in its efficacy in curing the infection. Thus our aim was to investigate in a single center the prevalence of metronidazole-resistant H. pylori over a period of 5 years. MATERIALS AND METHODS: A total of 1,015 different H. pylori strains collected over a period of 5 years were tested for sensitivity against metronidazole, ampicillin, tetracycline, and imipenem. Antibiotic sensitivity was tested by the disk diffusion and agar dilution methods. To elucidate further the possible relationship between these metronidazole-resistant strains, genomic DNA digestion by the Hae III endonuclease and ribotyping were undertaken in a selected group of isolates. RESULTS: In 1991, 29 of 132 (22.0%) tested strains of H. pylori were found to be resistant to metronidazole. Since our initiation at that time of a triple therapy of bismuth, metronidazole, and tetracycline, the prevalence of metronidazole-resistant strains rose rapidly to 73.2% in 1995. All H. pylori isolates were sensitive to ampicillin, tetracycline, and imipenem. A high degree of genomic heterogeneity was found among these isolates. Thus it is unlikely that the resistant strains of H. pylori were originated from a single clone. CONCLUSIONS: This study shows a rapid increase in metronidazole-resistant H. pylori with the use of an anti-Helicobacter regimen that contains metronidazole. We anticipate that the efficacy of metronidazole-containing anti-Helicobacter regimens will decline with the rapid rise in resistant strains of H. pylori.

In a 1400-bedded teaching hospital single-day prevalence surveys of hospital infection were done every six months for 3 years. The prevalence of community-acquired infection remained constant; but, after the introduction of a general infection-control policy, the prevalence of hospital-acquired infection (HAI) fell linearly from 10.5% in the second survey to 5.6% in the last. After the introduction of a specific urinary catheter care policy, the prevalence of hospital-acquired urinary tract infection (HAUTI) fell from 3.2% in the first four surveys to 2.0% in the last three. These differences persisted when the results were adjusted by logistic regression for patient risk factors, which varied between surveys: the declines for HAI and HAUTI were then 9.9% to 6.0% and 2.9% to 2.2% respectively. Infection control policies, therefore, can have substantial impact on the prevalence of HAI, and their effectiveness can readily be measured by repeated prevalence surveys.

Bacteriologic studies of bile and blood cultures of 579 patients with ductal stones and infected bile revealed that 121 patients (21%) had associated bacteremia. Analysis of bile and stone cultures showed that Escherichia coli, Klebsiella sp, Enterobacter sp, Enterococcus sp, and Streptococcus sp were the most commonly isolated bacteria. Two-thirds of the patients with bacteremia had similar organisms isolated from blood and bile. Pharmacokinetic studies of the hepatic/biliary excretion profiles of ceftazidime, cefoperazone, imipenem, netilmicin, and ciprofloxacin were performed by ERCP and nasobiliary catheter drainage. The bile samples obtained immediately after cannulation from patients with complete biliary obstruction contained low or undetectable levels of the antibiotics administered--the exception being ciprofloxacin, which was present at a concentration of 20% of the serum level. In vitro determination of minimum inhibitory concentration of the aforementioned antibiotics against 199 isolates of biliary pathogens revealed imipenem and ciprofloxacin to have the highest antimicrobial activity. Based on pharmacokinetic studies and in vitro susceptibility findings, we conclude that ciprofloxacin is superior to the other tested antibiotics in prophylaxis and treatment of biliary sepsis.

The activities of eight quinolones (ciprofloxacin, clinafloxacin, levofloxacin, ofloxacin, A-80556, sparfloxacin, temafloxacin and tosufloxacin) and three macrolides (azithromycin, clarithromycin and erythromycin) against 98 clinical isolates of Mycobacterium tuberculosis and 120 isolates of five different atypical mycobacterial species including 20 Mycobacterium kansasii, 25 Mycobacterium scrofulaceum, 25 Mycobacterium avium/intracellulare, 25 Mycobacterium chelonae and 25 Mycobacterium fortuitum were determined with the Middlebrook 7H9 broth macrodilution method. Sparfloxacin, clinafloxacin, levofloxacin, ciprofloxacin and ofloxacin were active against M. tuberculosis (MIC90 0.06-0.5 mg/L; MBC90 0.125-2.0 mg/L). However, higher MIC90S and MBC90S of these quinolones were obtained for strains of multi-drug resistant M. tuberculosis. The macrolides tested had poor activity against M. tuberculosis isolates (MIC90 > 8.0 mg/L). Furthermore, high MIC90S of the quinolones and macrolides (2.0 to 8.0 mg/L) were obtained for clinical isolates of atypical mycobacteria, with the exception of clarithromycin against M. kansasii (MIC90 = 1.0 mg/L) and sparfloxacin against M. scrofulaceum (MIC90 = 1.0 mg/L).

The prevalence of human papillomavirus (HPV) among 332 Hong Kong Chinese women with abnormal Papanicolaou smears were determined by polymerase chain reaction and restriction fragment length polymorphism analysis. The overall HPV positive rate was 44.3% with 18.6%(16/86) for normal/inflamed cervices, 36.4%(32/88) for condyloma, 64.7%(33/51) for cervical intraepithelial neoplasia grade 1 (CIN 1), 37.9%(11/29) for CIN 2, 68.3 (41/60) for CIN 3, and 77.8%(14/18) for carcinoma. Double HPV infection was detected in 17 of the 147 positive samples, with a significantly higher proportion in patients with normal or inflamed cervices than those with CIN or carcinoma (31.3% vs 10.5%, P =.029). The six most commonly identified genotypes were HPV 16 (33.3%), HPV 58 (23.8%), HPV 11, 18, 31 (8.8% each), and HPV 33 (6.8%). The worldwide uncommon genotype HPV 58 was found to be the second most common genotype detected in patients with cervical carcinoma (6 of 18 patients). HPV 58 infection showed a significant association with CIN/carcinoma (odds ratio [OR]= 3.98; 95% confidence interval [CI]= 1.22-14.35) and a significant trend of increase in prevalence with increasing severity of cervical lesion (chi(2)= 5.84; P =.016). Among Hong Kong Chinese women with abnormal cervical cytology, the detection of HPV 58 carried a positive predictive value of 68.6% for a cervical lesion of CIN 1 or higher severity. The high prevalence of HPV 58 among Chinese women, particularly in patients with carcinoma, has an implication on the design of HPV detection methods and the development of vaccines.