P. Y. Chau

Serodiagnosis of Penicillium marneffei infection.

Diagnosis of Penicillium marneffei infection is often made late. We evaluated an indirect immunofluorescent antibody test for P marneffei in serum from 103 patients with persistent fever and from 78 normal subjects. Germinating conidia (initial tissue-invasion phase) and yeast-hyphae (tissue multiplication phase) forms were used as antigen. All 8 documented P marneffei cases (8%) had an IgG titre of 160 or more; the other 95 patients and all the healthy controls had an IgG titre of 40 or below. Blood culture was positive in only 1 case with HIV infection. Biopsy and culture of tissues were necessary for confirmation in the other 7 cases. The test could provide rapid presumptive diagnosis and supplement conventional culture.

β-Lactamases in Shigella flexneri isolates from Hong Kong and Shanghai and a novel OXA-1-like β-lactamase, OXA-30.

ABSTRACT Ninety-one ampicillin-resistant Shigella flexneristrains from Hong Kong and Shanghai were studied for production of β-lactamases. TEM-1-like and OXA-1-like enzymes were identified in 21 and 79% of the strains, respectively, by isoelectric focusing (IEF). No difference in the pattern of β-lactamase production was found between strains from Hong Kong and Shanghai. Four ribotypes were detected. Over 88% of OXA-producing strains had the same ribotype. All TEM-1-like strains harbored a plasmid which hybridized positively with theblaTEM probe. Total DNA from OXA-1-like strains failed to hybridize or only hybridized weakly with an OXA probe. The OXA resistance was not transferable. OXA-1-like enzymes exhibited substrate and inhibition profiles similar to that of OXA-1 and were shown to have a pI of 7.3 by further IEF using a narrow-range ampholine gel. The gene encoding the OXA-1-like enzyme from one isolate (CH-07) was cloned, sequenced, and found to differ from blaOXA-1 at codon 131 (AGA→GGA; Arg to Gly), resulting in the novel designation OXA-30. The predominance of OXA-type enzymes in ampicillin-resistantS. flexneri suggests host preference for specific β-lactamases.

Use of PCR in routine diagnosis of treated and untreated pulmonary tuberculosis.

AIMS--To assess the routine use of a polymerase chain reaction (PCR) assay for the direct detection of Mycobacterium tuberculosis in expectorated sputum specimens. METHODS--A pair of primers (20-mer) were designed to amplify the 38 kilodalton protein of M tuberculosis. The specificity of the assay was evaluated in 31 M tuberculosis strains, 15 atypical mycobacterium species, and several commensal bacteria of the upper respiratory tract. The assay was subsequently applied to 519 sputum specimens from 85 inpatients of a chest hospital in Hong Kong. RESULTS--An amplified product of 239 base pairs was found in all M tuberculosis strains, standard strains of M bovis, and M africanum but not in the other bacterial strains tested. For the 51 patients with pulmonary radiographic lesions, the diagnosis of pulmonary tuberculosis was subsequently confirmed by both culture and PCR in 41 of them. Five patients who were treated before admission were positive by PCR alone. All but one patient in the control group (patients with acute exacerbation of chronic obstructive airway diseases) or those with atypical mycobacterial diseases were PCR negative. The PCR remained positive after four weeks of anti-tuberculosis treatment in 29 patients, 16 of whom had become culture negative. CONCLUSION--This PCR assay is a useful technique for the diagnosis of untreated and recently treated cases of pulmonary tuberculosis.

Streptococcus zooepidemicus (Lancefield group C) septicaemia in Hong Kong

The clinical findings relating to 11 patients in Hong Kong (HK) and to 43 patients described elsewhere, all with Streptococcus zooepidemicus septicaemia, are reviewed. There was a particular association with cardiovascular disease (27%) with seven cases of endocarditis, three of abdominal aortic aneurysm and two of deep venous thrombosis. Associations not previously reported included two cases of pharyngitis and two patients with persistent post-operative fever. The overall mortality was 22%. Both human and porcine strains of S. zooepidemicus from HK did not hydrolyse aesculin in contrast to the aesculin-positive biotypes reported previously. HK strains also had very mucoid colonies and capsules of hyaluronic acid were seen in electron micrographs. Samples of chromosomal DNA, extracted by means of HindIII restriction endonuclease, of strains from human beings and pigs were identical. The MIC of penicillin for all strains was less than or equal to 0.03 mg/l but the MBC for all was greater than 32 mg/l. Penicillin alone is generally sufficient for cure but combination with an aminoglycoside may be indicated in seriously ill patients. In our locality, pigs were incriminated as a possible source of human infection whereas consumption of contaminated dairy products is important elsewhere.

Salmonella serotypes and incidence of multiply-resistant salmonellae isolated from diarrhoeal patients in Hong Kong from 1973–82

Salmonella was the most frequent bacterial pathogen isolated from patients with acute diarrhoea in Hong Kong. In Queen Mary Hospital, the major hospital on Hong Kong Island, 94.7% of salmonellae isolated from faecal specimens from patients during the period 1973-82 belonged to the gastroenteric group, while 5.3% belonged to the enteric fever group. Amongst the gastroenteric group, 68 salmonella serotypes were identified, with Salmonella derby, S. typhimurium and S. anatum being the predominant ones. Three outbreaks caused by S. johannesburg, S. worthington and S. wandsworth were detected. Of S. typhimurium, 61.6% were resistant to multiple antibiotics and belonged to four major phage types: 193, 22, 138 and U288. The majority (96.8%) of S. johannesburg strains which caused a widespread epidemic were multiply-resistant. Multiple antibiotic resistance was rarely observed in most other gastroenteric salmonellae. S. typhi was the commonest of the enteric fever group isolated from the blood of patients. Nineteen phage types were identified; E1 being the commonest (18.5%) while 21% were nontypable. Many of these isolated were resistant to streptomycin or sulphadiazine, but none were resistant to ampicillin, chloramphenicol or trimethoprim.

Ofloxacin compared with amoxycillin in treating infective exacerbations in bronchiectasis

Forty-one hospitalized adult patients of bronchiectasis (non-cystic fibrotic) with infective exacerbations were entered into a randomized, double-blind, placebo-controlled study comparing ofloxacin (200 mg tid) and amoxycillin (1 g tid) both orally for ten days. In the ofloxacin group (20 patients), improvement in sputum purulence was excellent in 14, and fair in five patients with one failure. In the amoxycillin group (21 patients), improvement in sputum purulence was excellent in eight, fair in five and poor in eight patients. Mean drug levels on day 5 were 4.1 mg l-1 for serum (2 h post-dosage) and 4.0 mg l-1 for sputum for ofloxacin, and 18.4 mg l-1 for serum and 0.3 mg l-1 for sputum for amoxycillin. Ofloxacin thus yielded higher sputum concentration and appeared to be more effective and also better tolerated than amoxycillin in infective episodes of bronchiectasis.

The value of routine bronchial aspirate culture at fibreoptic bronchoscopy for the diagnosis of tuberculosis

We review the results of bronchial aspirate culture for mycobacteria sent routinely in a series of 1734 fibreoptic bronchoscopic procedures. The incidence of tuberculosis in the series was 8.3% (144 cases). Of these cases, a positive bronchial aspirate culture was obtained in 119 (82.6%) cases, and it was the exclusive means of diagnosis in 64 (44.4%). In 66% of these cases tuberculosis was not suspected at the time of bronchoscopy. Our results suggest that in an area with a high prevalence of tuberculosis, routine bronchial aspirate culture is a useful adjunct to diagnosis.

IS6110 based amplityping assay and RFLP fingerprinting of clinical isolates of Mycobacterium tuberculosis.

AIMS--To evaluate the usefulness of two IS6110 based typing methods, an amplityping assay and restriction fragment length polymorphism (RFLP) analysis, for fingerprinting respiratory isolates of Mycobacterium tuberculosis. METHODS--For amplityping, a pair of primers which amplify the intervening sequence between the repetitive insertion sequence IS6110 was used to generate a banding pattern which was confirmed by hybridisation. This assay was compared with conventional chromosomal DNA RFLP typing in the evaluation of 110 epidemiologically diverse isolates. RESULTS--Polymerase chain reaction (PCR) amplityping generated a single pattern in Hong Kong Chinese strains, but two and four diverse patterns in Filipino and Vietnamese strains, respectively, and could be completed within four days. When compared with chromosomal DNA RFLP typing, which took three weeks to complete, four different RFLP patterns could be seen among the Chinese strains, while seven patterns were found in the Filipino and Vietnamese strains. No change in amplityping or RFLP patterns was found in 36 sequential isolates from the same patients after anti-tuberculosis treatment for up to 12 months, despite the emergence of resistance in three of these strains. No specific amplityping or RFLP pattern could be related to different patterns of drug susceptibility. CONCLUSION--PCR amplityping could be used initially as a rapid typing method to distinguish strains originating from different localities. This could be important for investigation of outbreaks of tuberculosis--for example, in refugee camps.

An evaluation of inpatient consultations conducted by clinical microbiologists in a teaching hospital.

A systematic procedure for conducting consultations by clinical microbiologists requested by their clinical colleagues is described. The method was evaluated over a period of 17 months and involved sequential consultations related to 229 patients with known or probable infections. An attempt was made to elucidate the contributions of the clinical microbiologists in achieving a better understanding of the problems experienced in this particular setting and which in turn led to improved management of patients. It is hoped that this paper may provide a practical working framework for clinical microbiologists in the care of patients suffering from infection.

A double-blind randomized study comparing ofloxacin and amoxicillin in treating infective episodes in bronchiectasis

Summary32 hospitalized adult patients with infective episodes of bronchiectasis were enrolled in an ongoing double-blind, placebo-controlled study comparing ofloxacin with amoxicillin. They were randomized to receive either 200 mg ofloxacin or 1 g amoxicillin, both t.i.d.orally for ten days. In the ofloxacin group (15 patients), clinical response was excellent (clinical cure) in 11 and fair (clinical improvement or early reinfection) in three patients with one failure. In the amoxicillin group (17 patients), clinical response was excellent in six, fair in five, and poor (treatment failure) in six patients. Ofloxacin levels at 2 h (day 5) were 2.3 to 8.2 mg/l (mean 3.9 mg/l) for serum and 1.3 to 15 mg/l (mean 4.5 mg/l) for sputum. Sputum: serum ratio was 1.2:1. Amoxicillin levels at 2 h were 10 to 40 mg/l (mean 19.9 mg/l) for serum and 0 to 1.5 mg/l (mean 0.3 mg/l) for sputum, with no amoxicillin detected in sputum in 10 of 17 patients. Sputum: serum ratio was 0.02:1. One patient in the ofloxacin group had nausea. In the amoxicillin group, four patients had nausea and stomach pain, one had vertigo and one had transient peripheral eosinophilia. Ofloxacin thus yielded higher sputum concentration and appeared to be more effective and better tolerated than amoxicillin in infective episodes of bronchiectasis.ZusammenfassungIn einer noch nicht abgeschlossenen Placebo-kontrollierten Doppelblindstudie zum Vergleich von Ofloxacin und Amoxicillin wurden 32 erwachsene stationäre Patienten mit einem infektiösen Schub bei Bronchiektasie behandelt. Zufallsgemäß erhielten sie zehn Tage lang entweder 200 mg Ofloxacin oder 1 g Amoxicillin dreimal täglich oral verabreicht. In der Ofloxacingruppe (15 Patienten) wurde in 11 Fällen ein hervorragendes Therapieergebnis (klinische Heilung), bei drei Patienten ein befriedigendes Therapieergebnis (klinische Besserung oder frühe Reinfektion) und in einem Fall Therapieversagen beobachtet. In der Amoxicillingruppe (17 Patienten) sprachen sechs Patienten ausgezeichnet auf die Therapie an, bei fünf war das Ergebnis befriedigend und bei sechs Patienten schlecht (Therapieversagen). 2 h nach Applikation von Ofloxacin wurden am fünften Therapietag Ofloxacinserumspiegel von 2,3 bis 8,2 mg/l (im Mittel 3,9 mg/l) und Sputumspiegel von 1,3 bis 15 mg/l (im Mittel 4,5 mg/l) gemessen. Der Quotient von Sputum- und Serumkonzentration betrug 1,2:1. Die Amoxicillinserumspiegel 2 h nach Applikation betrugen 10 bis 40 mg/l (im Mittel 19,9 mg/l) und die Sputumkonzentrationen 0 bis 1,5 mg/l (im Mittel 0,3 mg/l). Bei zehn der 17 Patienten war Amoxicillin im Sputum nicht nachzuweisen. Der Quotient von Sputum- und Serumkonzentration betrug 0,02:1. Bei einem Patienten der Ofloxacin-Gruppe trat Übelkeit auf. In der Amoxicillin-Gruppe klagten vier Patienten über Übelkeit und Magenschmerzen, einer über Schwindel, und ein Patient hatte eine vorübergehende Blut-Eosinophilie. Ofloxacin erreichte im Sputum in der Behandlung infektiöser Episoden bei Bronchiektasie höhere Konzentrationen und schien wirksamer und besser verträglich zu sein als Amoxicillin.