[Investigation of cross-infection of Pseudomonas aeruginosa in an intensive care unit].

OBJECTIVE: To investigate the factors responsible for Pseudomonas aeruginosa nosocomial cross-infection in the intensive care unit (ICU) and provide effective measure for the prevention and management. METHODS: The homology of 7 Pseudomonas aeruginosa strains isolated from the patients in the ICU and the environment was examined by biological, serological, drug-resistance and plasmid analysis. RESULTS: The results of serological and plasmid analyses had good consistency, which demonstrated that the 7 Pseudomonas aeruginosa strains originated from solution in the oxygen humidifier, with uniform serological and plasmid type, and belonged to the same clone with cross-infection by contact between the patients or nursing staff and the objects in the ICU. CONCLUSION: Serological and plasmid analyses are more practical for identifying the sources of Pseudomonas aeruginosa cross-infection, which can be prevented by strict disinfection of the instrument and supervision of the nursing staff in the ICU.

[Investigation of the bacteria in the seawater of Xisha in the South China Sea and their antibiotic sensitivity profile].

OBJECTIVE: To investigate the distribution and antibiotic sensitivity of the bacteria in the seawater of Xisha in the South China Sea. METHODS: The samples of the seawater in Xisha were collected for bacterial counting, identification and antibiotic sensitivity tests. RESULT: Of the 84 bacterial strains isolated from the 80 seawater samples, 38 (45.24%) belonged to Vibrio alginolyticus, 11 (13.10%) to Sphingomonas, 9 (10.72%) to Comamonas terrigena, 7 (8.33%) to Werepseudomonas, 6 (7.14%) to Moraxella, 5 (5.95%) to Cedeceadavisae, and 8 to other bacteria including 2 Aeromona, 2 Acinetobacter, 1 Pantoea agglomerans, 1 Kingella kingae, 1 Shewanella putrefaciens and 1 Suttonella indologenes. Tests of the antibiotic sensitivity showed that all the bacteria were high sensitive to 16 kinds of the antibiotics with the exception of Vibrio alginolyticus, Sphingomonas and comamonas terrigena that were less sensitive to aztreonam or piperacillin and Sphingomonas to cefotaxime or cefepime. CONCLUSION: The investigation will be of great significance for early-stage prevention and cure of bacterial infection acquired from the seawater.

[Survey on drug resistance of Staphylococcus to commonly used antibiotics].

OBJECTIVE: To obtain primary knowledge of drug resistance of Staphylococcus, especially methicillin-resistant Staphylococcus (MRS), so as to facilitate clinical decision over the choice of appropriate antibiotics. METHOD: A total of 105 strains of Staphylococcus aureus, Staphylococcus epidermidis and other coagulase-negative Staphylococcus,were isolated from blood, sputum, pus and secretion sample from in-patients of Nanfang Hospital from January to July, 2002, and their status of drug-resistance was examined. RESULTS: MRS was isolated from 68.8% of the samples, and 69.6% of these isolates were methicillin-resistant Staphylococcus aureus (MRSA) and 63.3% resistant Staphylococcus epidermidis (MRSE). The rate of multi-drug resistance for MRS was much higher than that for methicilllin-susceptible Staphylococcus (MSS), and MRSA showed high multidrug resistance rates (all>50%) to the antibiotics erythromycin, imipenem, amikacin, SXT, ciprofloxacin, which fell into 4 categories according to their different antibiotic mechanisms. CONCLUSIONS: The prevalence and high MDR rate of MRS isolated form the samples suggest that in cases of infection, identification of the pathogenic bacterium should be routinely performed. Besides controlling MRS infection, importance should also be given to its prevention.

[Survey on drug resistance to ciprofloxacin in common pathogenic bacteria].

OBJECTIVE: To obtain primary knowledge of drug resistance to ciprofloxacin in the common pathogenic bacteria in this hospital thereby to bring the situation under control. METHODS: A total of 3 800 strains of pathogenic bacteria were isolated from in-patients from 1997 to 2000, and drug resistance of these strains to ciprofloxacin was examined. RESULTS: During the past 4 years, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis were found to be highly resistant to ciprofloxacin with the rates still on the rise from 50%, 25.6% and 40.3% in 1997 to 62.2%, 53.4% and 63.6% respectively in 2000. Over 40% of Escherichia coli, Klebsiella pneumoniae and Enterobacter were resistant to ciprofloxacin and the percentages for Pseudomonas aeruginosa and Acinetobacter reached 31.1% to 34.0% in 2000. Among the 189 strains of the pathogenic bacteria isolated from patients with sustained infection in our hospital in 2000, over 70% of Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis were identified as having resistance to ciprofloxacin. CONCLUSION: The percentages of common pathogenic bacteria that are resistant to ciprofloxacin have been considerably high and tend to increase further. Ciprofloxacin abuse needs to be given appropriate attention.