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Part I: Antibiotic resistance - Local scenario

1.1 Background: the problem of antimicrobial resistance (AMR) in Hong Kong (HK)

  1. The emergence of AMR has threatened the successful treatment of patient with infections (1–5).
  2. AMR increases drug costs and length of hospital stay, and adversely affects patient’s outcome (6).
  3. Resistance to all classes of antibiotics has developed to various extents among common and important nosocomial pathogens (Tables 1.1,1.2,1.3).
  4. In HK, methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum β-lactamase (ESBL)-producing E. coli are the two most important multidrug-resistant organisms (Table 1.4). Increase in the annual number of vancomycin-resistant Enterococcus faecium (VREfm) in 2013 and 2014 was attributed to a major interhospital outbreak which was eventually controlled. Carbapenem-resistant Acinetobacter and carbapenemase-producing Enterobacteriaceae (CPE) are on the rise (Figure 1.3).
  5. Factors contributing to the rapid rising and high prevalence of AMR in HK (7):
    • Hospital: overcrowding, manpower shortage, lapse in infection control measures, inappropriate use of antibiotics, environmental contamination, lack of transparency of surveillance data and lack of incentive in healthcare setting at administrative level.
    • Community: antimicrobial misuse including in animal husbandry, lack of awareness, and inadequate food and personal hygiene.

 

Table 1.1 Top eight organisms isolated from different clinical specimens in 2016. Data from a regional hospital in HK

Blood Respiratory specimens Urine
Organism Non-ICU/ HDU rank ICU/ HDU rank Organism Non-ICU/ HDU rank ICU/ HDU rank Organism Non-ICU/ HDU rank ICU/ HDU rank
E. coli 1 (31%) 2 (9%) P. aeruginosa 1 (12%) 2 (7%) E. coli 1 (33%) 2 (20%)
Klebsiella spp. 2 (12%) 6 (6%) H. influenzae 2 (9%) - Candida spp. 2 (13%) 1 (35%)
CoNS1 3 (9%) 1 (28%) S. aureus 3 (8%) 3 (6%) Enterococcus spp. 3 (12%) 3 (17%)
S. aureus 4 (7%) 4 (8%) Klebsiella spp. 4 (6%) 1 (8%) Klebsiella spp. 4 (10%) 4 (8%)
Enterococcus spp. 5 (4%) 3 (8%) A. baumannii 5 (4%) 7 (3%) Proteus spp. 5 (5%) 8 (1%)
P. aeruginosa 6 (2%) 7 (4%) S. maltophilia 6 (3%) 4 (6%) P. aeruginosa 6 (4%) 5 (5%)
Bacillus spp.1 7 (2%) - Enterobacter spp. 7 (3%) 5 (4%) CoNS1 7 (3%) 6 (4%)
P. mirabilis 8 (2%) - E. coli 8 (3%) 6 (3%) S. agalactiae 8 (3%) -

 

Note:

1Some of these could be contaminants
CoNS, coagulase-negative staphylococci; ICU, intensive care unit; HDU, high dependency unit

 

Table 1.2 Intrinsic and associated resistance to antimicrobial agents among five nosocomial pathogens

Bacteria Intrinsic resistance Associated resistance
MRSA All ß-lactams1, ß-lactam/ß-lactamase inhibitor combinations Common:
erythromycin, clindamycin, aminoglycosides, cotrimoxazole, fluoroquinolones
VREfm Glycopeptides, cotrimoxazole, clindamycin, aminoglycosides Common:
ampicillin, carbapenems, fluoroquinolones, high level aminoglycoside resistance
ESBL-producing Enterobacteriaceae (CTX-M, SHV-, TEM-derived) All cephalosporins including third generation cephalosporins, (variable activity against fourth-generation cephalosporins), all penicillins and monobactams Common:
fluoroquinolones, aminoglycosides, cotrimoxazole
Carbapenem-resistant Enterobacteriaceae (CRE) All ß-lactams including carbapenem (except monobactam) Common:
fluoroquinolones, aminoglycosides, cotrimoxazole
Carbapenem-resistant A. baumannii (CRAB) Cross-resistance to other ß-lactams are common Common:
fluoroquinolones, aminoglycosides, cotrimoxazole

 

Note:

1Except anti-MRSA cephalosporins such as ceftaroline

 

Table 1.3 Resistance of common bacterial isolates from all specimens in four regional hospitals (Kowloon, Hong Kong Island and the New Territories) in 2015

Organisms (No. of isolates) % Non-susceptible
Ampicillin Ampicillin + sulbactam Amoxicillin + clavulanate Piperacillin Ticarcillin + clavulanate Piperacillin + tazobactam Cefoperazone + sulbactam Cefuroxime (parenteral) Ceftriaxone Ceftazidime Cefepime Gentamicin Amikacin Ciprofloxacin Cotrimoxazole Imipenem Nitrofurantoin
Escherichia coli (26,943) 76   26     5 4.9 33 36 20 19 30 2 40 50 <1 3
Klebsiella spp. (8,958) 100   27   29 8 6 27 20 18 10 8 1 15 29 <1 45
Enterobacter spp. (2,094) 95   96   34 22 13 40   24 5 3 <1 5 11 2 27
Acinetobacter spp. (2,461)   50     56 56 48     34 53 31 26 56 30 55  
Pseudomonas aeruginosa (8,151)       9 43 4 11     5 4 1 <1 10   8  
Stenotrophomonas maltophilia (1,088)         40         44       22 5 100  

 

Note:

The results were interpreted according to the Clinical Laboratory Standards Institute (CLSI), M100–S20. Most ceftriaxone-non-susceptible isolates were ESBL-producers.

 

Table 1.4 Estimates of microorganisms significantly associated with AMR, HK, 2013–2016

Antibiotic-resistant microorganism Included in estimates Number of cases by year4
2013 2014 2015 2016
MRSA Blood only 672 671 686 816
ESBL-producing E. coli Blood only 1,319 1,371 1,470 1,470
ESBL-producing Klebsiella spp. Blood only 186 175 199 207
Carbapenem-resistant Acinetobacter Blood only 93 108 113 84
 
MRSA All clinical specimens 12,462 12,305 12,864 13,001
ESBL-producing E. coli All clinical specimens 10,778 10,954 11,436 11,033
ESBL-producing Klebsiella spp. All clinical specimens 2,502 2,592 2,777 2,917
Carbapenem-resistant Acinetobacter spp. All clinical specimens 2,684 3,314 3,359 3,191
Multidrug-resistant Acinetobacter spp.1 All clinical specimens 1,161 1,598 969 665
Ceftazidime-resistant Pseudomonas aeruginosa All clinical specimens 850 847 900 1,030
Vancomycin-resistant Enterococcus spp.2 All clinical specimens 1,810 1,321 410 232
Erythromycin-resistant Streptococcus pyogenes3 All clinical specimens 556 614 528 620
Multidrug-resistant Pseudomonas aeruginosa1 All clinical specimens 18 16 6 9
 
Clostridium difficile Stool only 2,077 2,171 2,130 2,167

 

Note:

  1. 1Per surveillance definitions used by the Hospital Authority (HA).
  2. 2Mostly vancomycin-resistant Enterococcus faecium.
  3. 3Erythromycin-resistant strains are also resistant to other macrolides such as clarithromycin and azithromycin.
  4. 4Annual number of cases was estimated by using microbiological results collected from all HA laboratories. Each patient was only counted once in the estimation.