Background
Klebsiella spp. is ubiquitous in nature.
Klebsiella pneumoniae (K. pneumoniae) is an opportunistic pathogen associated with both community-acquired and nosocomial infections, causing pneumoniae, abscess, bacteremia, and urinary tract infections [
1], and occasionally causes diarrhea in humans [
2,
3].
The surveillance on diarrhea-syndrome outpatients included any age people in Beijing, involving 245 sentinel hospitals from all 16 districts. Stool specimens were collected from diarrhea-syndrome outpatients in sentinel hospitals [
4], and tested the common diarrhea induced pathogens including rotavirus, norovirus, diarrheagenic
Escherichia coli,
Salmonella, and
Shigella spp. [
5]. Because the increasingly nosocomial infections caused by
K. pneumoniae might impose an increasing risk of infections in communities, from 2010 to 2015,
K. pneumoniae testing was included into the exiting diarrhea-syndrome surveillance with objective to estimate the prevalence of
K. pneumoniae in diarrhea-syndrome outpatients, test antibiotics susceptibility and investigate microbiological characteristics.
Discussion
K. pneumoniae is one of the most common Gram-negative pathogen found in human’s nasopharynx and in the intestinal tract [
1]. It existed with 60–70% the carrier rate in the hospital environment, and was notified as a common pathogen caused nosocomial infection [
1]. However, the community-acquired
K. pneumoniae infection was rare reported. This study, through inclusion of
K. pneumoniae into the existing diarrhea-syndrome surveillance, was able to detect
K. pneumoniae infection in community and its risk for possible persistent transmission in population in Beijing.
The detection rate of
K. pneumoniae in stool specimens from outpatients with diarrhea syndromes was about 0.5% (22/4340), which further demonstrated the existence of the community-acquired
K. pneumoniae infection [
11]. The prevalence in this study was much lower than the previous detection rate of
K. pneumoniae in stool samples ranges from 5 to 38% in hospital patients [
11], which emphasized the importance of nosocomial infection control as well necessary vigilance for detecting community-acquired
K. pneumoniae.
Less similarity of the strains typed by PFGE or MLST indicated the unlikely long-term transmission of
K. pneumoniae in the community. This study identified ST23 as the most common genotype, which were reported in many previous hospital-acquired infection studies in Asia [
12,
13]. Noticeable this study isolated one ST65 strain, a mucoid phenotype and harbored
rmpA gene for aerobactin, which more likely caused community-acquired infection [
14,
15] and indicated as one of the independent risk factors for bacteremia in patients with pneumonia [
13]. Moreover, the microbiological character of newly detected ST2362, ST2363, ST2364, ST2365, ST2366, ST2367, ST2368, ST2369, and ST2370, these strains presented clinical character are not thoroughly explicit, which needs further studies.
No ESBL production strains existed from stool specimens of diarrhea-syndrome outpatients in recent years illustrated that the community-acquired
K. pneumoniae was not a serious public health problem. All the strains were sensitive to some antibiotics (e.g., cephalosporins, quinolones, and fluoroquinolones) universally in use for clinical treatment. However, hospital-acquired
K. pneumoniae infection with resistance to multiple antibiotics agents has been increasing [
16]. The
Klebsiella species strains (e.g., TEM-type and SHV-type ESBLs, CTX-M type ESBLs) caused several predominant nosocomial infections [
17]. This study did not identify the drug resistance for
K. pneumoniae strains, but the diarrhea-syndrome surveillance identified serious drug resistance for
Shigella spp. [
4]. Given the consideration of horizontal transfer of drug resistance related genes as one of the most important mechanisms for the dramatically quickly dissemination of multi drug resistance among bacteria [
18], monitoring the drug resistance of the community-acquired
K. pneumoniae strains can provide a significant signal of drug resistance in population.
Authors’ contributions
BL participated in molecular genetic studies and drafted the manuscript; XZ and YH participated in sample collection and antimicrobial susceptibility testing; HZ carried out the data analysis; MQ and QW participated in the design of the study. All authors read and approved the final manuscript.
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