INTRODUCTIONCommunity-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged worldwide. In contrast to healthcare-associated MRSA (HA-MRSA), CA-MRSA isolates are usually susceptible to multiple non-beta-lactam antibiotics and cause a distinct spectrum of infections in epidemiologically disparate populations - in particular, cutaneous abscesses, necrotising fasciitis and necrotising pneumonia. They arise from a broader genetic background, and possess differing virulence genes. We aim to describe the distribution of different molecular subtypes of CA-MRSA among various regions and discuss briefly the implications of CA-MRSA from a local perspective.

METHODSLiterature review of articles on CA-MRSA, focusing mainly on reports where the genetic background of isolates had been analysed using multi-locus sequence typing (MLST). Singapore data were obtained from the local CA-MRSA database.

RESULTSMLST analysis demonstrated the presence of epidemic subtypes of CA-MRSA within most geographic areas. In parts of the United States, community MRSA infections currently exceed those caused by their methicillin-susceptible counterparts. In Singapore, CA-MRSA infections are increasing, predominantly as a result of the spread of ST30 clones.

CONCLUSIONAvailable evidence suggests that the emergence of MRSA from the community is not going to be a transient phenomenon. Local guidelines for dealing with this phenomenon at both therapeutic and preventive levels are needed prior to the potential development of a situation mirroring that of meso-endemic HA-MRSA in local hospitals or CA-MRSA epidemics in parts of USA.

Bacterial Typing Techniques ; Community-Acquired Infections ; epidemiology ; microbiology ; Cross Infection ; diagnosis ; microbiology ; Humans ; Methicillin Resistance ; Risk Factors ; Singapore ; epidemiology ; Staphylococcal Infections ; epidemiology ; microbiology ; Staphylococcus aureus ; classification ; drug effects

OBJECTIVETo monitor genotypes and drug-resistance trend of Acinetobacter baumannii (AB) isolated from burn wards.

METHODSTwenty-six strains of AB isolated from wound secretion, venous catheter, and blood were collected from burn patients hospitalized in our burn wards from November 2008 to February 2009, and June to September 2010. Homogeneous genotype analysis was performed with repetitive extragenic palindromic PCR, and drug-resistance rate to 13 antibiotics including amikacin, gentamicin, etc., which were commonly used in clinic, was tested by K-B paper disk diffusion. The data of drug-resistance rate were processed with chi-square test.

RESULTS(1) Sixteen AB strains were multi-drug resistant (MDR), 9 AB strains were pan-drug resistant (PDR). Among all strains, the resistance rate to gentamicin, piperacillin, piperacillin/tazobactam, cefuroxime, cefotaxime, ceftazidime, cefepime, ciprofloxacin, imipenem, and meropenem was respectively higher than 90.00%; the resistance rate against cefoperazone/sulbactam was the lowest (11/26, 42.31%). There were obvious difference among the drug-resistance rates of AB strains to 13 antibiotics (with rates from 42.31% to 100.00%, χ(2) = 97.371, P < 0.05). (2) There were 7 genotypes among 26 AB strains, respectively type A (17), type B (3), type C (2), type D (1), type E (1), type F (1), and type G (1). Out of the 17 AB strains in A genotype, 1 strain was from 2008, 1 strain was from 2009, 15 strains were from 2010, and among them 11 strains were collected from wound secretion and 6 strains were obtained from blood and venous catheter.

CONCLUSIONSAB strains in A genotype are dominant in our burn wards in recent years, which are MDR or PDR to commonly used antibiotics. Cefoperazone/sulbactam is the drug of choice for burn patients with AB infection.

Acinetobacter Infections ; epidemiology ; microbiology ; Acinetobacter baumannii ; drug effects ; genetics ; Burns ; microbiology ; Cross Infection ; epidemiology ; microbiology ; Drug Resistance, Multiple, Bacterial ; Genes, Bacterial ; Humans

In order to investigate the distribution of nosocomial infection in patients with hematological diseases in our hospital, and to explore the changes of the pathogens isolated. The method of retrospective investigation and analysis was employed. 1164 strain pathogens were isolated from the patients with hematological diseases during the period of 1997-2009. The results showed that the Gram-positive cocci infection increased gradually during the 13 years, but has been stable in the last 4 years. The Gram-negative bacteria showed a trend decrease. The fungi increased during these years. The rates of infection with gram-positive cocci, gram-negative bacteria and fungus were 28.2%, 59.8% and 12.0% respectively. For the details, Escherichia coli infection rate was the highest: 12.1%, followed by Pseudomonas aeruginosa (9.1%), Enterobacter (8.4%), Klebsiella pneumoniae (7.4%), Staphylococcus epidermidis (6.3%) and Enterococci (6.6%). The distribution of G(+)- and G⁻ pathogens showed obvious change on end of 1990's and beginning of this century, but it was tending towards stability on recent years; the incidence of fungus was tending towards increase, which was related to wide application of strong broad-spectrum antibiotics. In conclusion, the patients with hematological diseases, as the high-risk group of nosocomial infection, should be monitored strictly. Infection is related to many factors, and the main factor is dysfunction of autoimmunity. The strategies should be explored to strengthen the immune protection and set up a reasonable scheme of antibiotics.
Adult ; Bacterial Infections ; epidemiology ; Cross Infection ; epidemiology ; microbiology ; Escherichia coli ; isolation & purification ; Female ; Gram-Negative Bacterial Infections ; epidemiology ; microbiology ; Gram-Positive Bacterial Infections ; epidemiology ; microbiology ; Hematologic Diseases ; epidemiology ; microbiology ; Humans ; Incidence ; Male ; Middle Aged ; Young Adult

Nosocomial infections (NIs) are a critical issue affecting the quality of healthcare. In this study, we performed a retrospective study to explore the incidence rates, mortality rates, and microbial spectrum of NIs in Beijing Chest Hospital, a tuberculosis (TB) specialized hospital in China. Our data demonstrate that the overall incidence rate of inpatients with NIs slightly decreased from 2012 to 2016, which may be associated with the implementation of hand hygiene measures, while the mortality rates associated with NI did not significantly change. In addition, the species distribution of NIs was quite different from that presented in previous reports, and Klebsiella pneumoniae was the most frequently isolated microorganism.
Bacteria ; classification ; isolation & purification ; Beijing ; Cross Infection ; epidemiology ; microbiology ; mortality ; Hospitals, Chronic Disease ; Humans ; Infection Control ; Population Surveillance ; Retrospective Studies ; Tuberculosis ; epidemiology ; therapy

OBJECTIVETo investigate the etiology and epidemic characteristics of hospital acquired pneumonia (HAP) in children.

METHODA retrospective hospital infection study was performed in 52,639 children admitted to our hospital from January 2005 to December 2008.

RESULTSix hundred and ninety eight patients were diagnosed as HAP. The incidence of HAP was 1.33%, among which, 108 (15.47%) cases were early-onset HAP and 590 (84.53%) were late-onset HAP. The HAP patients aged 3 days to 15 years (503 male and 195 female). The proportion of patients younger than 1 year was 51.4%. Main underlying diseases were cytomegalovirus hepatitis, congenital heart disease, malignant tumor, granulocytopenia or agranulocytosis, prematurity and low birth weight. There was significant difference in the incidences among different departments with the highest one seen in ICU, followed by departments of infectious diseases, hematology and digestive diseases. Two hundred and thirty one stains of pathogens were identified from sputum of 355 cases. One hundred and fifty six (67.5%) strains were Gram-negative bacteria, which accounted for the highest proportion. There were 30 (13.0%) Gram-positive bacterial strains, and 29 (12.6%) respiratory tract virus strains, and 15 (6.5%) fungal strains, and 1 (0.4%) mycoplasma strain. The predominant bacterial pathogens were Klebsiella pneumoniae, followed by Stenotrophomonas maltophilia, Burkholderia cepacia, Escherichia coli and Acinetobacter baumannii. The isolation rates of Klebsiella pneumoniae and Escherichia coli with positive extended-spectrum beta-lactamases (ESBLs) were 94.8% and 85.7%, respectively. Those two bacteria were universally resistant to the third and forth generations cephalosporins. The main pathogens of early-onset HAP were respiratory syncytial virus (RSV), Streptococcus mitis, Streptococcus pneumonia, Haemophilus influenzae and Klebsiella pneumoniae, while the main pathogens of late-onset HAP were ESBLs-positive Klebsiella pneumonia, Stenotrophomonas maltophilia, Burkholderia cepacia, Escherichia coli and Acinetobacter baumannii.

CONCLUSIONHAP in children is most common in children younger than 1 year and with underlying diseases. The main pathogens are Gram-negative bacteria. RSV was an important pathogen of HAP. The pathogens of early-onset HAP are different from those of late-onset HAP. These results may be of some help in prevention and control of HAP in children and in guiding for rational application of antibiotics, especially the empirical antibiotic choice.

Adolescent ; Child ; Child, Preschool ; Cross Infection ; epidemiology ; microbiology ; Drug Resistance, Bacterial ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Pneumonia ; epidemiology ; microbiology ; Retrospective Studies

OBJECTIVETo investigate and take a case study on a Klebsiella pneumoniae outbreak in a newborn intensive care unit (NICU).

METHODSUsing epidemiological investigation method to cultivate bacilli and detect the homology.

RESULTSKlebsiella pneumonia was detected in 4 NICU patients. Based on environmental sample analyses, four Klebsiella pneumonia strains were identified and confirmed to be highly homologous. The outbreak was effectively controlled after the strict implementation of hand hygiene practice and environment disinfection.

CONCLUSIONKlebsiella pneumonia outbreak in NICU may be caused by the route of hand transmission.

Cross Infection ; epidemiology ; microbiology ; Disease Outbreaks ; Female ; Humans ; Infant, Newborn ; Intensive Care Units, Neonatal ; Klebsiella Infections ; epidemiology ; microbiology ; Klebsiella pneumoniae ; genetics ; isolation & purification ; Male

Aged ; Aged, 80 and over ; Corynebacterium ; isolation & purification ; Cross Infection ; epidemiology ; microbiology ; Female ; Humans ; Male ; Random Amplified Polymorphic DNA Technique

OBJECTIVETo investigate the incidence of nosocomial infections of newborn infants in neonates and to explore the risk factors and strategies of infection control.

METHODSThere were 433 confirmed cases of nosocomial infection in the neonatal ward of the authors' hospital from January 2007 to December 2009. Their data of epidemiological and clinical characteristics, results of etiological examinations and antibiotic resistance were retrospectively analyzed.

RESULTSDuring the study, the number of hospitalizations were 6437. Nosocomial infection occurred in 433 patients 513 times. The overall nosocomial infection rate was 6.82%. The overall hospitalization days were 73 663 and nosocomial infection patient-day rates were 6.96‰. The VAP infection rate was 28.7‰. The CRBSI rate was 3.5‰. Gestational age (OR = 1.049), mechanical ventilation (OR = 1.810), umbilical vein catheter (OR = 1.106), hospitalization days (OR = 1.081), premature rupture of membrane (OR = 1.433) were the risk factors for the development of nosocomial infection. There were 197 (38.4%) cases of pneumonia, which was the most common nosocomial infection in Neonatal Ward. There were 129 cases of ventilator-associated pneumonia (VAP), which accounts for 65.5% of pneumonia and 24.4% of cases treated with ventilator. The next was sepsis, 124 cases (24.2%) and 64 cases of diarrheal disease (12.7%). One hundred and eighty two (54.4%) strains of isolates were Gram-negative bacteria, which accounted for the highest proportion. The predominant pathogens of Gram-negative bacteria were Klebsiella pneumoniae (19.6%), followed by Acinetobacter baumannii (8.1%), Pseudomonas aeruginosa (7.2%), Stenotrophomonas maltophilia (4.8%) and Escherichia coli (4.8%). The isolation rates of Klebsiella pneumoniae and Escherichia coli with positive extended-spectrum beta-lactamases (ESBLs) were 91.4% and 75%, respectively. Those two bacteria were universally resistant to cephalosporins. The rate of resistance to imipenem of Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa were 1.5%, 11.1% and 41.7%. The isolation rates of methicillin-resistant Staphylococcus aureus and methicillin-resistant coagulase-negative Staphylococcus were 28.6% and 95.5%.

CONCLUSIONIt is important to identify the high risk factors for nosocomial infections in newborn infants. To shorten time for mechanical ventilation and hospitalization days, removal of the central venous catheter as early as possible would be conducive to reducing the morbidity of nosocomial infection. The main pathogens were Gram-negative bacteria. The multidrug resistance of Enterobacteriaceae and Non-fermenters is serious.

Cross Infection ; epidemiology ; microbiology ; Female ; Humans ; Incidence ; Infant, Newborn ; Intensive Care Units, Neonatal ; Retrospective Studies ; Risk Factors

During a four-week period, four healthy term newborn infants born at a regional maternity hospital in Korea developed late-onset neonatal group B Streptococcus (GBS) infections, after being discharged from the same nursery. More than 10 days after their discharge, all of the infants developed fever, lethargy, and poor feeding behavior, and were subsequently admitted to the Korea University Medical Center, Ansan Hospital. GBS was isolated from the blood cultures of three babies; furthermore, GBS was isolated from 2 cerebral spinal fluid cultures. Three babies had meningitis, and GBS was isolated from their cerebral spinal fluid cultures. This outbreak was believed to reflect delayed infection after early colonization, originating from nosocomial sources within the hospital environment. This report underlines the necessity for Korean obstetricians and pediatricians to be aware of the risk of nosocomial transmissions of GBS infection in the delivery room and/or the nursery.
Time Factors ; *Streptococcus agalactiae/isolation & purification ; Streptococcal Infections/*epidemiology/microbiology/transmission ; Pregnancy ; Meningitis, Bacterial/epidemiology/microbiology/transmission ; Male ; Korea/epidemiology ; Infant, Newborn ; Humans ; Hospitals, Maternity ; Female ; *Disease Outbreaks ; Cross Infection/*epidemiology/microbiology/transmission

PURPOSETo investigate and analyze the clinical and etiological characteristics of community-acquired intraabdominal infections (CIAIs) and hospital-acquired or nosocomial intraabdominal infections (NIAIs) in a comprehensive hospital, to understand the characteristics, pathogen composition, and drug resistance of CIAIs as well as NIAIs, and to provide a reference for clinical treatment.

METHODSWe collected the clinical data of patients with intraabdominal infections admitted to our hospital from June 2013 to June 2014. In vitro drug sensitivity tests were conducted to separate pathogens, and the data were analyzed using the WHONET 5.4 software and SPSS 13.0 software.

RESULTSA total of 221 patients were enrolled in the study, including 144 with CIAIs (55 mild-moderate and 89 severe) and 77 with NIAIs. We isolated 322 pathogenic strains, including 234 strains of gram-negative bacteria, 82 strains of gram-positive bacteria, and 6 strains of fungi. Based on clinical features, NIAIs and severe CIAIs presented significantly higher values in age, length of hospital stay, mortality, and the incidence of severe intra-abdominal infection than mild-moderate CIAIs (p < 0.05). There was no significant difference in the prognosis between NIAIs and severe CIAIs. Primary diseases leading to CIAIs and NIAIs mostly were hepatobiliary diseases and gastrointestinal diseases respectively. Bacteria isolated from various types of IAIs mainly were Enterobacteriaceae; mild-moderate CIAIs mostly were mono-infection of gram-negative bacteria; NIAIs mostly were mixed infections of gram-negative and gram-positive bacteria; and severe CIAIs were from either type of infection. The rate of Extended Spectrum b-Lactamase-producing Escherichia coli and Klebsiella pneumoniae was much higher in NIAIs than in CIAIs (p < 0.05). The antimicrobial drug sensitivity of gram-negative bacteria isolated from NIAIs was significantly lower than that of CIAIs.

CONCLUSIONCIAIs and NIAIs have their own unique clinical features and epidemiological features of pathogens which should be considered during the initial empiric therapy for the rational use of antimicrobial drugs. Regional IAIs pathogenic bacteria have their own features in drug resistance, slightly different from some recommendations of 2010 Infectious Diseases Society of America guidelines.

Adult ; Aged ; Bacterial Infections ; drug therapy ; epidemiology ; Community-Acquired Infections ; drug therapy ; epidemiology ; microbiology ; Cross Infection ; drug therapy ; epidemiology ; microbiology ; Female ; Humans ; Intraabdominal Infections ; drug therapy ; epidemiology ; microbiology ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Prospective Studies