Antibiotic resistance has evolved over the past 50 years from a merely microbiological curiosity to a serious medical problem in hospitals all over the world. Resistance has been reported in almost all species of gram-positive and -negative bacteria to various classes of antibiotics including recently developed ones. Bacteria acquire resistance by reducing permeability and intracellular accumulation, by alteration of targets of antibiotic action, and by enzymatic modification of antibiotics. Inappropriate use of an antibiotic selects resistant strains much more frequently. Once resistant bacteria has emerged, the resistance can be transferred to other bacteria by various mechanisms, resulting in multiresistant strains. MRSA is one of the typical multiresistant nosocomial pathogens. A study of the PFGE pattern of endonuclease-digested chromosomal DNA showed that MRSA of a few clones were disseminated among newborns in the NICU of a Japanese hospital. In this regard, it is important to choose appropriate antibiotics and then after some time, to change to other classes to reduce the selection of resistant strains. Since the development of epoch-making new antibiotics is not expected in the near future, it has become very important to use existing antibiotics prudently based on mechanisms of antibiotic action and bacterial resistance. Control of nosocomial infection is also very important to reduce further spread of resistant bacteria.
Cross Infection/physiopathology ; Drug Resistance, Microbial/physiology* ; Enzymes/physiology ; Methicillin Resistance/physiology ; Staphylococcus aureus/physiology

BACKGROUNDSevere acute respiratory syndrome (SARS) is characterized by both an atypical pneumonia and efficient nosocomial transmission. However, it remains unknown whether the infectivity and the virulence of the pathogen will change throughout the successive transmission. This study was conducted to compare the clinical features and management regimens of patients with SARS among the multiple generations from nosocomial transmission initiated by a super-spreader.

METHODSThe clinical data of 84 epidemiologically-linked SARS patients from a hospital outbreak were retrospectively studied. All patients, in whom a clear-cut transmission generation could be noted, had a direct or indirect exposure to the index patient and the epidemic successively propagated through the multiple generations of cases within a short period of time.

RESULTSThere were 66 women and 18 men with mean age of (29.2 +/- 10.3) years in this cluster; and 96.4% of whom were health care workers. Detailed contact tracing identified 35 (41.7%) first-generation cases, 34 (40.5%) second-generation cases, and 15 (17.8%) third-generation cases. No statistical differences among the multiple generations of transmission were found in terms of age, gender, incubation period and length of hospital stay. With the advanced transmission generations, the initial temperature lowered, the number of cases with dry cough decreased. There were no statistical differences in the peak temperature and duration of fever, other accompanying symptoms, leucopenia; however, the time from initial pulmonary infiltrates to radiographic recovery shortened (P < 0.05). No differences were found in maximum number of lung fields involved, duration from the onset of fever to the occurrence of pulmonary infiltrates and time from the initial pulmonary infiltrate to its peak among the multiple transmission generations (P > 0.05). No statistical differences were found in modes of oxygen therapy and sorts of antibiotics prescribed among the various transmission generations (P > 0.05); however, as with the advanced transmission generations, the number of cases prescribed with methylprednisolone, human gamma-globulin, interferon-alpha, antiviral drugs (oral ribavirin or oseltamivir) increased (P < 0.05) and time from admission to starting these medication shortened (P < 0.05).

CONCLUSIONSThere is no evidence that SARS infection will evolve or transmit within a fashion that permits it to become less powerful throughout the successive transmission within a short time.

Adult ; Contact Tracing ; Cross Infection ; physiopathology ; Female ; Humans ; Male ; Personnel, Hospital ; Retrospective Studies ; Severe Acute Respiratory Syndrome ; physiopathology ; transmission

Infective endocarditis (IE) has been increasingly diagnosed in patients without previously detected predisposing heart disease, but its clinical features have yet to be fully determined. A recent single-center study including echocardiographic images and surgical findings investigated the incidence of undiagnosed, clinically silent valvular or congenital heart diseases and healthcare-associated infective endocarditis (HAIE). The study confirmed that a large proportion of patients with IE have no previous history of heart disease. Analysis of underlying disease in these patients showed that undetected mitral valve prolapse was the most common disease, followed by an apparently structurally normal valve. The patients who developed IE of apparently structurally normal valves had different clinical characteristics and worse outcomes. IE involving a structurally normal valve was associated with both nosocomial and non-nosocomial HAIE, whereas community-acquired IE was more frequent than HAIE. The pathophysiologic mechanism involving the development of non-HAIE or community-acquired IE due to predominantly staphylococcal infection in an apparently structurally normal valve is not yet clearly understood. Structurally normal valves are not necessarily free of regurgitation or abnormal turbulence and, given the dynamic nature and fluctuating hemodynamic effects of conditions such as poorly controlled hypertension, end-stage renal disease, and sleep apnea, further investigation is necessary to evaluate the potential role of these diseases in the development of IE. An apparently normal-looking valve is associated with IE development in patients without previously recognized predisposing heart disease, warranting repartition of at-risk groups to achieve better clinical outcomes.
Adult ; Aged ; Community-Acquired Infections/diagnosis/*epidemiology/microbiology/physiopathology/therapy ; Cross Infection/diagnosis/*epidemiology/microbiology/physiopathology/therapy ; Echocardiography, Doppler, Color ; Endocarditis, Bacterial/diagnosis/*epidemiology/microbiology/physiopathology/therapy ; Female ; Heart Valves/*microbiology/physiopathology/ultrasonography ; Humans ; Incidence ; Male ; Middle Aged ; Predictive Value of Tests ; Prognosis ; Risk Factors

INTRODUCTIONUrinary tract infections remain one of the most frequently encountered acquired complications in an intensive care unit (ICU). The objective of this study was to determine the incidence, risk factors, microbial sensitivity patterns, and clinical outcomes of patients with UTIs acquired during their admission to an ICU in an acute care hospital in Singapore.

MATERIALS AND METHODSThis was a 14-week prospective study. All ICU patients > or =18 years who remained in the ICU for > or =48 hours were eligible for this study. Patients were reviewed daily and the presence of an ICU-acquired UTI was identified via urinary microscopic examination or culture results. Other data collected included patient demographics, ICU admission criteria, concomitant illnesses, presence of invasive lines, microbial sensitivity and treatment outcomes.

RESULTSThirty-fi ve (13.7%) cases of ICU-acquired UTI occurred in 256 separate ICU admissions. The most common micro-organisms isolated were Candida spp. (34%). Female gender and prior exposure to antibiotics were independent risk factors for developing an ICU-acquired UTI (P <0.01). Both mean length of ICU stay and duration of catheterisation were significantly longer for patients with ICU-acquired UTI (P <0.001). The mortality rate of patients with ICU-acquired UTIs (12.1%) was slightly higher than those without (9.9%).

CONCLUSIONSThe incidence of ICU-acquired UTIs was similar to figures reported for nosocomial UTIs from the previous studies. Significant risk factors for developing an ICU-acquired UTI were female gender and history of antibiotic exposure prior to ICU admission. The insignificant link between ICU-acquired UTI and mortality requires further investigation in larger cohorts.

Adult ; Aged ; Aged, 80 and over ; Cross Infection ; Female ; Humans ; Intensive Care Units ; Length of Stay ; Male ; Middle Aged ; Outcome Assessment (Health Care) ; Prospective Studies ; Risk Factors ; Singapore ; epidemiology ; Urinary Tract Infections ; epidemiology ; etiology ; physiopathology ; Young Adult