Part I: Antibiotic resistance - Local scenario
1.7 Macrolide Resistant Mycoplasma pneumoniae (MRMP)
- Respiratory tract infections caused by Mycoplasma pneumoniae is primarily a disease of school-age children and adolescents (Figure 1.5). Infections are often self-limiting even without specific antibiotic treatment.
- MRMP was first reported in Japan in 2001 (100). Since then, there has been reports in China (101–104), Taiwan (105–106), Korea (107), the United States of America (108–109) and various European countries, including Scotland (110), Spain (111) and Germany (112).
- In China, the prevalence of MRMP is exceptionally high constituting over 90% of all Mycoplasma pneumoniae isolates (102). The first imported case of MRMP in HK was reported in an adult returning from Xi’an in 2009 (113). The first locally acquired case of MRMP in HK has been reported in 2010 (114).
- Two local studies have described the rate of MRMP among patients requiring hospital admission. The first study evaluated different molecular methods to detect genotypic resistance in M. pneumoniae in both adult and paediatric subjects (115). Pyrosequencing identified mutation at the position A2063G in 79% of the M. pneumoniae PCR positive cases, where Sanger sequencing and melting curve analysis only identified the genotypic mutation in less than 40% of the PCR positive cases. The difference is mainly due to the ability of pyrosequencing to identify low-frequency MRMP quasispecies. Another local study evaluated the antibiotics treatment efficacy against MRMP in the paediatric age group only (116). Among the paediatric community-acquired pneumonia (CAP) cases with a positive Mycoplasma PCR, 70% were MRMP. A recent study has demonstrated a high rate of M. pneumoniae-associated pneumonia in younger children, where 18% were infants of age group 0–1 years and 30% were between 2–11 years.
- According to the CHP laboratory surveillance statistics from January to September 2016, 35% of the M. pneumoniae detected in respiratory specimens harboured a macrolide-resistant mutation (117).
Figure 1.4 Changes in the multidrug-resistant rate of Acinetobacter baumannii according to three different definitions, 1997–2008
Definition 1: resistance to carbapenem class (imipenem, meropenem)
Definition 2: resistance to representative agents from at least three antibiotic classes, including aminoglycosides (gentamicin, amikacin), antipseudomonal penicillins (ticarcillin/clavulanic acid, piperacillin/ tazobactam), carbapenems (imipenem, meropenem), cephalosporins (ceftazidime) and fluoroquinolones (ciprofloxacin)
Definition 3: resistance to all agents or with the exception of amikacin
Figure 1.5 Prevalence of Mycoplasma pneumoniae in respiratory specimens according to patient age groups, all HA hospitals, 2015–2016. During the period, over 20,000 respiratory specimens were tested by PCR assays. In HK, annual M. pneumoniae-positive rate in respiratory specimens have been reported to vary widely, ranging from 9.8% to 27.2% (118).