Antimicrobial resistance of bacterial isolates from respiratory care wards in Taiwan: a horizontal surveillance study comparison of the characteristics of nosocomial infection and antimicrobial-resistant bacteria in adult Intensive Care Units and two respiratory care facilities for mechanically ventilated patients at a tertiary care centre in Taiwan

Hospital-wide comparison of health care-associated infection among 8 intensive care units: A retrospective analysis for 2010-2015

BACKGROUND

Exploring the distribution of nosocomial pathogens among different categories of intensive care units (ICUs) is critical to improving the management of health care-associated infection (HAI). Despite both single- and multicenter studies, the nature of the variations of HAIs within various ICUs remains inadequately evaluated.

METHODS

Data on HAIs at our hospital during the period January 2010-December 2015 were collected from 8 ICUs, namely, respiratory, cardiovascular, neurology, neonatal, hematology, emergency, cardiothoracic surgery, and neurosurgery ICUs, at a tertiary hospital.

RESULTS

We observed a cumulative HAI incidence of 15.6/1,000 patient-days among 6,254 cases of infection at the hospital, as well as obvious interunit variations in HAI distribution. Acinetobacter baumannii was the leading organism of infection in almost every ICU, especially in emergency, neurosurgery, and neonatal ICUs. The most common pathogens were Pseudomonas aeruginosa in the cardiothoracic surgery, emergency, and neonatal ICUs; Klebsiella pneumoniae and Escherichia coli in the neurosurgery, emergency, neonatal, and neurology ICUs; and Candida albicans in both neurology and emergency ICUs.

CONCLUSIONS

Our findings revealed that A baumannii and P aeruginosa were the most common pathogens associated with invasive operations, whereas K pneumoniae and E coli were the most common pathogens in the medical ICUs.

Dynamic change of surface microbiota with different environmental cleaning methods between two wards in a hospital

Terminal disinfection and daily cleaning have been performed in hospitals in Taiwan for many years to reduce the risks of healthcare-associated infections. However, the effectiveness of these cleaning approaches and dynamic changes of surface microbiota upon cleaning remain unclear. Here, we report the surface changes of bacterial communities with terminal disinfection and daily cleaning in a medical intensive care unit (MICU) and only terminal disinfection in a respiratory care center (RCC) using 16s ribosomal RNA (rRNA) metagenomics. A total of 36 samples, including 9 samples per sampling time, from each ward were analysed. The clinical isolates were recorded during the sampling time. A large amount of microbial diversity was detected, and human skin microbiota (HSM) was predominant in both wards. In addition, the colonization rate of the HSM in the MICU was higher than that in the RCC, especially for Moraxellaceae. A higher alpha-diversity (p = 0.005519) and a lower UniFrac distance was shown in the RCC due to the lack of daily cleaning. Moreover, a significantly higher abundance among Acinetobacter sp., Streptococcus sp. and Pseudomonas sp. was shown in the RCC compared to the MICU using the paired t test. We concluded that cleaning changes might contribute to the difference in diversity between two wards.

Acquisition of Mycobacterium abscessus among ventilator-dependent patients in Taiwan chronic respiratory care facilities

AIM

To investigate the acquisition of Mycobacterium abscessus among ventilator-dependent patients.

MATERIALS & METHODS

We prospectively recruited ventilator-dependent patients in five respiratory care wards (RCWs). Respiratory specimens were cultured for mycobacteria on day 1 (D1), 3 months (M3) and 6 months (M6) after enrollment.

RESULTS

72 patients had cultures taken at all three time points. The proportion of patients with a culture positive for M. abscessus increased from 15.3% (11/72) on D1 to 30.6% (22/72) at M3 and 38.9% (28/72) at M6. Two M. abscessus subspecies abscessus isolates obtained from different patients had identical randomly amplified polymorphic DNA patterns. Being in RCW D and advanced age were significantly associated with initial cultures positivity.

CONCLUSION

Our study reveals that acquisition of M. abscessus was common among ventilator-dependent patients.

Application of 16S rRNA metagenomics to analyze bacterial communities at a respiratory care centre in Taiwan

In this study, we applied a 16S ribosomal RNA (rRNA) metagenomics approach to survey inanimate hospital environments (IHEs) in a respiratory care center (RCC). A total of 16 samples, including 9 from medical devices and 7 from workstations, were analyzed. Besides, clinical isolates were retrospectively analyzed during the sampling period in the RCC. A high amount of microbial diversity was detected, with an average of 1,836 phylotypes per sample. In addition to Acinetobacter, more than 60 % of the bacterial communities present among the top 25 abundant genera were dominated by skin-associated bacteria. Differences in bacterial profiles were restricted to individual samples. Furthermore, compliance with hand hygiene guidelines may be unsatisfactory among hospital staff according to a principal coordinate analysis that indicated clustering of bacterial communities between devices and workstations for most of the sampling sites. Compared to the high incidence of clinical isolates in the RCC, only Staphylococcus and Acinetobacter were highly abundant in the IHEs. Despite Acinetobacter was the most abundant genus present in IHEs of the RCC, potential pathogens, e.g., Acinetobacter baumannii, might remain susceptible to carbapenem. This study is the first in Taiwan to demonstrate a high diversity of human-associated bacteria in the RCC via 16S rRNA metagenomics, which allows for new assessment of potential health risks in RCCs, aids in the evaluation of existing sanitation protocols, and furthers our understanding of the development of healthcare-associated infections.

Risk assessment of ischemic stroke associated pneumonia

BACKGROUND

Cerebral stroke is a disease with a high disability rate and a high fatality rate. This study was undertaken to assess the risk of stroke associated pneumonia (SAP) in patients with ischemic stroke using A2DS2 score.

METHODS

Altogether 1 279 patients with ischemic stroke who were treated in our department from 2009 to 2011 were retrospectively analyzed with A2DS2 score. A2DS2 score was calculated as follows: age ≥75 years=1, atrial fibrillation=1, dysphagia=2, male sex=1; stroke severity: NIHSS score 0-4=0, 5-15=3, ≥16=5. The patients were divided into three groups according to A2DS2 score: 620 in score 0 group, 383 in score 1-9 group, and 276 in score ≥10 group. The three groups were comparatively analyzed. The diagnostic criteria for SAP were as follows: newly emerging lesions or progressively infiltrating lesions on post-stroke chest images combined with more than two of the following clinical symptoms of infection: (1) fever ≥38 °C; (2) newly occurred cough, productive cough or exacerbation of preexisting respiratory tract symptoms with or without chest pain; (3) signs of pulmonary consolidation and/or wet rales; (4) peripheral white blood cell count ≥10×10(9)/L or ≤4×10(9)/L with or without nuclear shift to left, while excluding some diseases with clinical manifestations similar to pneumonia, such as tuberculosis, pulmonary tumors, non-infectious interstitial lung disease, pulmonary edema, pulmonary embolism and atelectasis. The incidence and mortality of SAP as well as the correlation with ischemic stroke site were analyzed in the three groups respectively. Mean± standard deviation was used to represent measurement data with normal distribution and Student's t test was used. The chi-square test was used to calculate the percentage for enumeration data.

RESULTS

The incidence of SAP was significantly higher in the A2DS2 score≥10 group than that in the score 1-9 and score 0 groups (71.7% vs. 22.7%, 71.7% vs. 3.7%, respectively), whereas the mortality in the score≥10 group was significantly higher than that in the score 1-9 and score 0 groups (16.7% vs. 4.96%, 16.7% vs. 0.3%, respectively). The incidences of cerebral infarction in posterior circulation and cross-MCA, ACA distribution areas were significantly higher than those in the SAP group and in the non-SAP group (35.1% vs.10.1%, 11.4% vs. 7.5%, respectively). The incidence of non-fermentative bacteria infection was significantly increased in the score≥10 group.

CONCLUSIONS

A2DS2 score provides a basis for risk stratification of SAP. The prevention of SAP needs to be strengthened in acute ischemic stroke patients with a A2DS2 score≥10.

Prolonged clonal spreading and dynamic changes in antimicrobial resistance of Escherichia coli ST68 among patients who stayed in a respiratory care ward

From 2007 to 2009, we collected a total of 83 bacteraemic isolates of Escherichia coli with reduced susceptibility or resistance to third-generation cephalosporins (TGCs). Isolates were genotyped by PFGE and multilocus sequence typing (MLST). The PFGE patterns revealed two highly correlated clusters (cluster E: nine isolates; cluster G: 22 isolates) associated with this prolonged clonal spreading. Compared with cluster E isolates, cluster G isolates were significantly more likely to harbour aac(6')-Ib-cr (P<0.05), and most of these isolates were isolated during a later year than cluster E isolates (P<0.05). By MLST analysis, 94% of cluster E and G isolates (29/31) were ST68. Although no time or space clustering could be identified by the conventional hospital-acquired infection monitoring system, E. coli cases caused by cluster E and G isolates were significantly associated with having stayed in our hospital's respiratory care ward (P<0.05). Isolates obtained from patients who had stayed in the respiratory care ward had a significantly higher rate of aac(6')-Ib-cr and blaCTX-M-14 positivity, and were more likely to belong to ST68/S68-like (all P<0.05). To our knowledge, this is the first report of prolonged clonal spreading caused by E. coli ST68 associated with a stay in a long-term care facility. Using epidemiological investigations and PFGE and MLST analyses, we have identified long-term clonal spreading caused by E. coli ST68, with extra antimicrobial-resistance genes possibly acquired during the prolonged spreading period.

Risk assessment of ischemic stroke associated pneumonia

BACKGROUND

Cerebral stroke is a disease with a high disability rate and a high fatality rate. This study was undertaken to assess the risk of stroke associated pneumonia (SAP) in patients with ischemic stroke using A2DS2 score.

METHODS

Altogether 1 279 patients with ischemic stroke who were treated in our department from 2009 to 2011 were retrospectively analyzed with A2DS2 score. A2DS2 score was calculated as follows: age ≥75 years=1, atrial fibrillation=1, dysphagia=2, male sex=1; stroke severity: NIHSS score 0-4=0, 5-15=3, ≥16=5. The patients were divided into three groups according to A2DS2 score: 620 in score 0 group, 383 in score 1-9 group, and 276 in score ≥10 group. The three groups were comparatively analyzed. The diagnostic criteria for SAP were as follows: newly emerging lesions or progressively infiltrating lesions on post-stroke chest images combined with more than two of the following clinical symptoms of infection: (1) fever ≥38 °C; (2) newly occurred cough, productive cough or exacerbation of preexisting respiratory tract symptoms with or without chest pain; (3) signs of pulmonary consolidation and/or wet rales; (4) peripheral white blood cell count ≥10×10(9)/L or ≤4×10(9)/L with or without nuclear shift to left, while excluding some diseases with clinical manifestations similar to pneumonia, such as tuberculosis, pulmonary tumors, non-infectious interstitial lung disease, pulmonary edema, pulmonary embolism and atelectasis. The incidence and mortality of SAP as well as the correlation with ischemic stroke site were analyzed in the three groups respectively. Mean± standard deviation was used to represent measurement data with normal distribution and Student's t test was used. The chi-square test was used to calculate the percentage for enumeration data.

RESULTS

The incidence of SAP was significantly higher in the A2DS2 score≥10 group than that in the score 1-9 and score 0 groups (71.7% vs. 22.7%, 71.7% vs. 3.7%, respectively), whereas the mortality in the score≥10 group was significantly higher than that in the score 1-9 and score 0 groups (16.7% vs. 4.96%, 16.7% vs. 0.3%, respectively). The incidences of cerebral infarction in posterior circulation and cross-MCA, ACA distribution areas were significantly higher than those in the SAP group and in the non-SAP group (35.1% vs.10.1%, 11.4% vs. 7.5%, respectively). The incidence of non-fermentative bacteria infection was significantly increased in the score≥10 group.

CONCLUSIONS

A2DS2 score provides a basis for risk stratification of SAP. The prevention of SAP needs to be strengthened in acute ischemic stroke patients with a A2DS2 score≥10.

Epidemiology and antimicrobial resistance among commonly encountered bacteria associated with infections and colonization in intensive care units in a university-affiliated hospital in Shanghai

BACKGROUND/PURPOSE

The aim of this study was to classify intensive care unit (ICU) bacterial strains as either ICU-acquired or ICU-on-admission and to compare their epidemiological and antibiogram characteristics.

METHODS

The study was performed in a 1300-bed university-affiliated hospital from January 1, 2006 to December 31, 2010. Based on the time of ICU admission, ICU isolates were classified as ICU-acquired strains (appearing more than 48 hours after admission) or ICU-on-admission strains (appearing 48 hours or less from admission). The microbiological data before ICU admission, the microbiological data, and susceptibility testing were compared between the ICU-acquired and ICU-on-admission bacterial isolates.

RESULTS

The most common ICU-acquired strains were Acinetobacter baumannii (19.5%), Pseudomonas aeruginosa (15.6%), Stenotrophomonas maltophilia (11.5%), Staphylococcus aureus (10.7%), Enterococcus spp. (10.6%), and Klebsiella pneumoniae (9.7%). There were significant differences between ICU-acquired and ICU-on-admission isolates in the susceptibility rates of Gram-negative bacteria to antibiotics, especially the susceptibility of A. baumannii to imipenem [23.8% (ICU-acquired) vs. 44.4% (ICU-on-admission), p < 0.001] and meropenem (24.1% vs. 37.8%, p < 0.001), and the susceptibility of P. aeruginosa to imipenem (39.3% vs. 76.1%, p < 0.001) and meropenem (58.5% vs. 76.1%, p < 0.05). Furthermore, decreased susceptibility rates of A. baumannii and P. aeruginosa to carbapenems were correlated with an extended ICU stay (p < 0.05).

CONCLUSION

Because of decreasing susceptibility rates of pathogens (especially ICU-acquired strains) and a significant correlation with the length of ICU stay, intensivists should consider a patient's time of ICU admission and previous microbiological data and should distinguish ICU-acquired strains from non-ICU-acquired strains so as to initiate optimized empirical antibiotic therapy against ICU-acquired infections.