This systematic review and meta-analysis provide an overview of the spread of MR-MP infection in the world since 2017. The prevalence of MR-MP strains is a global and public health concern MR-MP strains emerged in 2000 and are spreading rapidly around the world (14). The highest resistance rates have been reported in Asia, mainly in China and Japan, at around 80–90%. (14–16)
The incidence of MRMP in Japan has decreased in recent years.(17) This decline has been recorded after the 2011–2012 outbreak. (18) MR-MP rates decreased to 11.3% during the 2018–2019 period (19) High levels of MR-MP were reported in China between the 2013 and2018 periods (20, 21). Regardless of Asia, the prevalence of MRMP in Europe is fairly low. The prevalence of MRMP is underestimated, as most European countries do not have national surveillance systems. This can be problematic because there is no rapid alert system to identify an increase in MRMP infection. (22) The recorded rates of macrolide resistance in Europe suggest that MRMP strains lack a competitive advantage in a population that moderately used macrolides (23, 24). Italy and Scotland report the highest MRMP prevalence during the 2010–2011 outbreak (11, 25), while the Netherlands and Finland have not had MR-MP infections. (14, 26) However, the sample sizes of the studies mentioned in this report were very different, so the prevalence rates should be carefully compared. The emergence of drug-resistant strains of MP can arise directly from the use of macrolides, even after a few days of treatment and especially when a patient receives suboptimal drug concentrations, as reported for other antibiotics. (11, 27)
Macrolide resistance in MP communicates with mutations in the 23S rRNA gene. (28) Various mutations in the 23S rRNA gene were detected at positions 2063, 2064, and 2617. (3, 29, 30) Among these genetic loci, the A2063G and A2064G mutations leads to high levels of macrolide resistance in M. pneumoniae. Notably, the A2063G mutation in domain V of the 23S rRNA gene results in the most prevalent macrolide-resistant M. pneumoniae isolated in China (31–35).
MP resistant rates may vary depending on the patient's background and the epidemiological situation of each country. For example, the decreased rate of MR-MP in recent years in Japan has been associated with the use of tosufloxacine, a fluoroquinolone, instead of macrolides for the treatment of MP infections (36). Moreover, the prevalence of the MP p1 type can also determine this recovery of sensitivity to macrolides in Japan. (36)
The benefits of using antibiotics to treat MP infections are not clear, as most infections are self-limiting. (37). Macrolides seem to reduce the duration of symptoms; however, it cannot be attributed to their antibacterial or anti-inflammatory properties (38).
Evidence on whether patients benefit from the use of additional corticosteroids in the treatment of MP infections is limited. (39). The reason for using additional corticosteroid therapy with antibiotics in the management of MP-infected patients with severe low respiratory tract infections is due to inflammation generated by an excessive immune response rather than by the pathogen itself (40).
Atypical pneumonia syndrome with fever, cough, and shortness of breath due to MP can be challenging to distinguish from SARS-CoV-2 infection based on clinical presentations alone. Physicians treating patients with COVID19 should be aware that other respiratory pathogens can cause coinfection. Coinfections of MP plus SARS-CoV-2 have been reported in the literature (41). Therefore, the SARSCoV2 diagnostic test should be performed in conjunction with testing for other respiratory pathogens to ensure better management of the patient.