Active surveillance culture in a critical care unit of a tertiary care hospital of West Bengal, India: a prospective study

Background: Hospital-acquired infections are a common and serious public health problem and their management and control are essential to minimize hospital-related morbidity and mortality. The aim was to acquire the base line data regarding prevalence of Multi Drug Resistant (MDR) organism in a tertiary care institution and to help in ensuring proper practice guidelines like contact isolation, cohorting and sterile barrier precaution. The study design was an observational descriptive hospital based cross sectional study.Methods: The study was conducted in a critical care unit of a tertiary care hospital for a duration of 6months. Patients with the age more than 18yrs, duration of stay more than 48hrs were included in the study. Categorical data are expressed in percentages.Results: In the study 111 patients more than 18 yrs of age were enrolled of which 68 were male and 43 females. The sample collected from the axillary site were 110, nasal site 108, urine 96 and respiratory site 95. The culture positivity for pathogenic organisms were maximum for axillary site (95.5%) followed by nasal site (83.33%), respiratory site (36.8%) and urine (26%). Of all the organisms isolated multidrug resistance were as follows: MRSA 63% and MSSA 37% (of all S. aureus), MR CoNS 41.32% (of all CoNS), ESBL producer 22.2% and carbapenemase producer 22.2% (of all Klebsiella species), ESBL producer 37.5% and carbapenemase producer 31.26% (of all E. coli), non albicans Candida 57.14% (of all Candida species).Conclusions: Early identification of the causative pathogen in nosocomial and community-acquired infection is crucial for initiating the correct antibiotics as well as preventing further spread.

Carbapenem-Resistant Enterobacteriaceae: Rapid Laboratory Diagnosis and Surveillance Culture for Infection Control / 대한내과학회지

Carbapenem-resistant Enterobacteriaceae (CRE) are increasing rapidly worldwide and in South Korea, which is a major problem for patient treatment and infection control. CRE is mainly due to carbapenem-hydrolyzing β-lactamase, which spreads through genetic mobile elements. Therefore, the rapid detection of carbapenemase-producing CRE (CP-CRE) and carrier surveillance are very important for infection control. Most clinical microbiology laboratories use automated real-time PCR methods for the rapid detection of CP-CRE; in some cases, additional accurate molecular tests are necessary. For the surveillance of risk groups, the complementary use of liquid culture and real-time PCR methods is important, taking into consideration their advantages and disadvantages. Furthermore, the expansion of surveillance targets is also necessary.

Methicillin-resistant Staphylococcus aureus (MRSA) carriage in a dermatology unit

OBJECTIVE: The aim of this study was to characterize Staphylococcus aureus (MRSA) carriage in a dermatology unit. METHODS: This was a prospective and descriptive study. Over the course of 26 weeks, surveillance cultures were collected weekly from the anterior nares and skin of all patients hospitalized in a 20-bed dermatology unit of a tertiary-care hospital. Samples from healthcare workers (HCWS) were cultured at the beginning and end of the study. Colonized patients were put under contact precautions, and basic infection control measures were enforced. Staphylococcus aureus colonization pressure was determined monthly. Colonized and non-colonized patients were compared, and isolates were evaluated for antimicrobial susceptibility, SCCmec type, virulence factors, and type. RESULTS: Of the 142 patients evaluated, 64 (45 percent) were colonized by MRSA (39 percent hospital acquired; 25 percent community acquired; 36 percent indeterminate). Despite isolation precautions, hospital-acquired Staphylococcus aureus occurred in addition to the continuous entry of Staphylococcus aureus from the community. Colonization pressure increased from 13 percent to 59 percent, and pemphigus and other bullous diseases were associated with MRSA colonization. Eleven out of 71 HCWs (15 percent) were Staphylococcus aureus carriers, although only one worker carried a persistent clone. Of the hospital-acquired MRSA cases, 14/28 (50 percent) were SCCmec type IV (3 PFGE types), 13 were SCCmec type III (46 percent), and one had an indeterminate type. These types were also present among the community-acquired Staphylococcus aureus isolates. SSCmec type IV isolates were shown to be more susceptible than type III isolates. There were two cases of bloodstream infection, and the pvl and tst virulence genes were absent from all isolates. CONCLUSIONS: Dermatology patients were colonized by community- and hospital-acquired Staphylococcus aureus. Half of the nosocomial Staphylococcus aureus isolates were SCCmec type IV. Despite the identification of colonized patients and the subsequent contact precautions and room placement, Staphylococcus aureus colonization continued to occur, and colonization pressure increased. Pemphigus and other bullous diseases were associated with Staphylococcus aureus.

The Effect of Contact Precautions and Active Surveillance Culture on the Methicillin-Resistant Staphylococcus aureus Reduction in an Intensive Care Unit / 병원감염관리

BACKGROUND: This study investigated the effectiveness of reinforced contact precautions and active surveillance cultures (ASCs) in reducing the incidence of methicillin-resistant Staphylococcus aureus (MRSA) and other healthcare-associated infections (HAIs). METHODS: A before- and after-experimental study was performed at the intensive care unit (ICU) in a university-affiliated hospital. Reinforced contact precautions were applied to all patients, and ASCs for MRSA were performed for newly admitted patients at the time of admission and once a week thereafter. The HAIs were investigated in accordance with the National Nosocomial Infections Surveillance (NNIS) definitions and compared before and after the interventions. The data were analyzed using descriptive statistics. RESULTS: The number of HAIs caused by MRSA decreased from 2.2 to 0.5 per 100 patients discharged (P=0.02) and from 3.6 to 1.0 per 1,000 patient-days (P=0.032). The number of overall HAIs decreased from 7.6 to 4.0 per 100 patients discharged (P=0.011) and from 12.7 to 7.3 per 1,000 patient-days (P=0.034). The invasive device-associated infections caused by MRSA and other pathogens decreased, but the decrease was not statistically significant. CONCLUSION: Reinforced contact precautions and ASCs were effective in decreasing both MRSA infections and overall HAIs in the ICU. Further, it was assumed that the incidence of device-associated infections would have decreased if the intervention period was extended.

Evaluation of MRSASelect for Detecting Methicillin-Resistant Staphylococcus aureus from Surveillance Specimens / 병원감염관리

BACKGROUND: A rapid and sensitive surveillance culture has a pivotal role in infection control of methicillinresistant Staphylococcus aureus (MRSA). This study was aimed to compare the performance of MRSASelect (Bio-Rad, France) to that of mannitol salt agar containing 6 microgram/mL of oxacillin (MSA-OX) for detecting MRSA in surveillance cultures. METHOD: From May to June 2006, 86 nasal swabs and 21 sputum specimens were enrolled. All specimens were inoculated onto MRSASelect and MSA-OX, which were incubated for 2 days and 3 days, respectively, and colonies were read daily by a technologist. Pink colonies on MRSASelect and yellow colonies on MSA-OX were examined with Gram stain, Pastorex(R) Staph-plus (Bio-Rad) and mecA-PCR. After the final reading, both media were re-examined by a superviser. RESULTS: Of the 107 specimens cultured, 32 (29.9%) were positive for MRSA. Of these, 27 were detected by both media, one by MSA-OX only, and 4 by re-examination. The day-1 and day-2 sensitivities/specificities of MRSASelect were 78.1%/97.3% and 84.4%/97.3%, respectively, while those of MSA-OX were 53.1%/100% and 78.1%/92.1%, respectively. With MRSASelect, two more positives were detected at day 2, but their incubation was less than 18 hour at day 1. There were six false positive organisms detected: three Enterobacter spp., one Acinectobacter spp., and two coagulase-negative staphylococci (CNS). But, the two CNS grew on MSA-OX only. CONCLUSION: MRSASelect with 1-day incubation showed a sensitivity equivalent to and a specificity better than MSA-OX with 2-day incubation. MRSASelect should be a useful medium for MRSA surveillance when it is read after an incubation of 18-28 hours with the confirmatory Gram stain of screen-positives.

Outbreak of Nosocomial Infections caused by Acinetobacter baumannii resistant to imipenem and Cefoperazone/Sulbactam / 병원감염관리

BACKGROUND: With increase of antibiotics use and invasive procedures, infections caused by multi-resistant Acinetobacter baumannii (MRAB) are increasing. Recently, we experienced the outbreak of- nosocomial infections caused by MRAB resistant to imipenem and cefoperazone/sulbactam in intensive care units (ICU) and general ward. We analyzed the clinical characteristics of the infected patients and antibiotic susceptibility of the organisms. And surveillance cultures and IRS-PCR were performed to find out the transmission route. METHODS: We collected data from physical examination and clinical records. We performed surveillance cultures of environment, patients not infected with MRAB in ICU, and hands of health care workers. RESULTS: Between November 1996 and June 1997, 49 strains of MRAB were isolated from the 26 patients hospitalized in Kangnam St. Mary' s Hospital. The lower respiratory infection (13 cases) was the most common infection and sputum was the most common sources (47.1%). All strains of MRAB showed the same genotype. In disk diffusion test, all strains were resistant to piperacillin, gentamicin, amikacin, ceftazidime, cefoperazone/sulbactam, aztreonam, imipencm, ciprofloxacin. From the surveillance cultures, the genotypically identical strains were isolated from ventilator Y-piece, the floor of ICU, and hands of health care workers. It suggested that this strain was transmitted through ventilatory device or hands of health care workers. We instructed all the health care workers to wash hands, to disinfect hospital environment completely. Since July 1997, no further case has occurred. CONCLUSIONS: Since A. baumannii could be transmitted through ventilatory devices and the hands of health care workers, it is important to wash hands and to disinfect hospital environment completely.