Antibiotic resistance at VINARES hospitals in Vietnam during 2012-2013

During the May meeting 2013 in Hanoi the laboratories were supplied with new ATCC-strains, McFarland standard and callipers for zone of inhibition measurement.
The resistance levels at nine Vietnamese laboratories were collected using WHO-net data.

 E. coli and K. pneumoniae

The resistance levels were monitored for SXT, ciprofloxacin, amikacin, gentamicin, tobramycin cefotaxime, ceftazidime and imipenem. The number of E. coli isolates was 1467 only counting one isolate per patient. Among these 220 (15%) were blood isolates. Corresponding number of K. pneumoniae isolates were 667 and 95 (14%).
Resistance to 3rd generation cephalosporins (ESBL-phenotype) was high among all isolates of E. coli (57%) and K. pneumoniae (36%). Blood isolates showed lower levels of ESBL-phenotype both among E. coli (37%) and K. pneumoniae (5.9%).

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Three labs tested more strains for ceftazidime than for cefotaxime and three labs tested more strains for cefotaxime than for ceftazidime. Three labs tested all strains with both cefotaxime and ceftazidime. It is important to test both ceftazidime and cefotaxime to detect ESBLs with different phenotypes.
High resistance levels were seen among E. coli isolates for most antibiotics (30-75%) except for amikacin (16%) and imipenem (1.3%). Resistance levels among K. pneumoniae isolates were 21-47% for all antibiotics except imipenem (3.1%).
Three laboratories reported carbapenem resistance for E. coli (0.3-9.1%) and two laboratories reported carbapenem resistance for K. pneumoniae (5-13%). No carbapenem resistance was seen among blood isolates of E. coli and K. pneumoniae. Blood isolates showed also lower resistance levels for all the other antibiotics E. coli (19-67%) and K. pneumoniae (2.2-13%).
Carbapenem resistance should always be tested by MIC. It is recommended to also test for the mechanisms of carbapenem resistance. Mechanisms of resistance is important to know and can be done by molecular methods.
P. aeruginosa
The resistance levels were monitored for ciprofloxacin, amikacin, gentamicin, tobramycin, ceftazidime and imipenem. The number of P. aeruginosa isolates was 667 only counting one isolate per patient. Among these only 33 (4.9%) were blood isolates.
High resistance levels were seen among P. aeruginosa isolates for all antibiotics (29-45%). Blood isolates showed lower resistance levels for ceftazidime, ciprofloxacin, and imipenem and hgher resistance levels for the aminoglycosides.
A. baumannii
The resistance levels were monitored for SXT, ciprofloxacin, amikacin, gentamicin, tobramycin, ticarcillin-clavulanic acid, ceftazidime and imipenem. The number of P. aeruginosa isolates was 423 only counting one isolate per patient. Among these 25 (5.9%) were blood isolates.
High resistance levels were seen among A. baumannii isolates for all antibiotics (57-77%). Blood isolates showed lower resistance levels for all the antibiotics (20-69%).
S. aureus
The resistance levels were monitored for oxacillin, cefoxitin, vancomycin, SXT, chloramphenicol, erythromycin, clindamycin, amikacin, gentamicin. The number of S. aureus isolates was 1351 only counting one isolate per patient. Among these 165 (12%) were blood isolates.

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