Sivaraman Umadevi

Ventilator-associated pneumonia.

BACKGROUND Ventilator-associated pneumonia (VAP) is a type of nosocomial pneumonia that occurs in patients who receive mechanical ventilation (MV). According to the International Nosocomial Infection Control Consortium (INICC), the overall rate of VAP is 13.6 per 1,000 ventilator days. The incidence varies according to the patient group and hospital setting. The incidence of VAP ranges from 13-51 per 1,000 ventilation days. Early diagnosis of VAP with appropriate antibiotic therapy can reduce the emergence of resistant organisms. METHOD The aim of this review was to provide an overview of the incidence, risk factors, aetiology, pathogenesis, treatment, and prevention of VAP. A literature search for VAP was done through the PUBMED/MEDLINE database. This review outlines VAPs risk factors, diagnostic methods, associated organisms, and treatment modalities. CONCLUSION VAP is a common nosocomial infection associated with ventilated patients. The mortality associated with VAP is high. The organisms associated with VAP and their resistance pattern varies depending on the patient group and hospital setting. The diagnostic methods available for VAP are not universal; however, a proper infection control policy with appropriate antibiotic usage can reduce the mortality rate among ventilated patients.

Changing Trends in Resistance Pattern of Methicillin Resistant Staphylococcus aureus

BACKGROUND Methicillin resistance in Staphylococcus aureus is associated with multidrug resistance, an aggressive course, increased mortality and morbidity in both community and health care facilities. Monitoring of newly emerging and prevalent Methicillin Resistant Staphylococcus aureus (MRSA) strains for their resistance patterns to conventional as well as novel drugs, are essential for infection control. AIMS To study the changing trends in resistance patterns of MRSA at our hospital. SETTINGS AND DESIGN This cross sectional study was carried out in a 750 bed tertiary care hospital in south India. MATERIAL AND METHODS One hundred and two clinical isolates of MRSA which were obtained in 2004-2011 were identified by using oxacillin, cefoxitin disc diffusion test and oxacillin screening agar test. Antibiotic susceptibility test was done for commonly used non beta lactam anti-Staphylococcal drugs, as well as for anti-MRSA drugs like vancomycin, linezolid, mupirocin and rifampicin. Minimum inhibitory concentration (MIC) of vancomycin was determined by using Vancomycin HiComb strip (Himedia, Mumbai, India). Statistical Analysis which was done: Chi-square test and proportions were used to compare the two groups. RESULTS MRSA isolates showed high resistance to co-trimoxazole (82.3%), ciprofloxacin (76.4%), gentamicin (64.7%) and tetracycline (49%) as compared to other drugs. High prevalence of ciprofloxacin resistance was detected, particularly among outpatients. Multi resistant MRSA with a ≥ 3 non-beta lactam agent resistance was 79%. All MRSA isolates were sensitive to vancomycin, linezolid, mupirocin and rifampicin. MRSA had displayed increase in resistance to most antibiotics except tetracycline in recent years. CONCLUSIONS Taking into consideration the prevalence of multidrug resistance in MRSA, resistance patterns should be evaluated periodically and antibiotic therapy should be guided by susceptibility testing.

Incidence and risk factors of ventilator associated pneumonia in a tertiary care hospital.

BACKGROUND Ventilator associated pneumonia (VAP) is a type of nosocomial pneumonia associated with increased morbidity and mortality. Knowledge about the incidence and risk factors is necessary to implement preventive measures to reduce mortality in these patients. METHOD A prospective study was conducted at a tertiary care teaching hospital for a period of 20 months from November 2009 to July 2011. Patients who were on mechanical ventilation (MV) for more than 48 hours were monitored at frequent intervals for development of VAP using clinical and microbiological criteria until discharge or death. RESULTS Of the 76 patients, 18 (23.7%) developed VAP during their ICU stay. The incidence of VAP was 53.25 per 1,000 ventilator days. About 94% of VAP cases occurred within the first week of MV. Early-onset and late-onset VAP was observed in 72.2% and 27.8%, respectively. Univariate analysis showed chronic lung failure, H2 blockers usage, and supine head position were significant risk factors for VAP. Logistic regression revealed supine head position as an independent risk factor for VAP. CONCLUSION VAP occurred in a sizeable number of patients on MV. Chronic lung failure, H2 blockers usage, and supine head position were the risk factors associated with VAP. Awareness about these risk factors can be used to inform simple and effective preventive measures.

Detection of extended spectrum beta lactamases, ampc beta lactamases and metallobetalactamases in clinical isolates of ceftazidime resistant Pseudomonas Aeruginosa

We studied the prevalence of ceftazidime resistance in Pseudomonas aeruginosa and the rates of extended-spectrum β-lactamase (ESBL), AmpC β-lactamase (AmpC) and metallo-β-lactamase (MBL) production among the ceftazidime resistant Pseudomonas aeruginosa. A very high rate of MBL production was observed, which suggested it to be an important contributing factor for ceftazidime resistance among Pseudomonas aeruginosa.

Detection of metallo-beta-lactamase producing Pseudomonas aeruginosa in intensive care units

BACKGROUND Metallo-beta-lactamase (MBL) producing Pseudomonas aeruginosa has emerged as a threat to hospital infection control, due to its multi-drug resistance, especially in intensive care units (ICUs). AIMS This study was carried out to detect MBL producing P. aeruginosa isolates from medical and surgical ICUs, to compare and evaluate different phenotypic methods currently in use and to determine antibiograms. METHOD A prospective study was undertaken to detect MBLs in P. aeruginosa isolates obtained from various clinical samples. A total of 49 strains were recovered from patients admitted in inpatient wards and ICUs, and screened for imipenem resistance by Kirby Bauer disk diffusion method. Detection of MBLs was further done by imipenem-EDTA disk synergy test and combined disk test. RESULTS Out of 49 isolates, 11 isolates (22.4 per cent) were imipenem resistant. All 11 imipenem resistant P. aeruginosa strains, when further tested, were positive for MBL production by combined disk test, but, only eight showed positive results by imipenem-EDTA disk synergy test. CONCLUSION MBL production was the main resistance mechanism in the 11 carbapenem resistant P. aeruginosa isolates collected, with multidrug resistance associating significantly with MBL production in P. aeruginosa from our institution.

Multi-drug resistant Acinetobacter species from various clinical samples in a tertiary care hospital from South India

BACKGROUND Acinetobacter species are gram-negative coccobacilli belonging to the group of Non-Fermenting Gram-Negative Bacilli, which are ubiquitous in nature. They cause outbreaks in intensive care units and healthcare settings, and are becoming increasingly drug resistant. AIMS To determine the prevalence of multi-drug resistant Acinetobacter species from various clinical samples. METHOD Clinical samples were processed as per standard microbiological techniques. Antibiotic susceptibility testing was carried out on all the Acinetobacter isolates by Kirby- Bauer disc diffusion method as per CLSI guidelines. RESULTS A total of 122 Acinetobacter spp. were isolated. 110 (90.16 per cent) were from inpatients, and 12 (9.83 per cent) were from outpatients. Out of 122 isolates, 44 (36.06 per cent) were from the ICU. The majority of the isolates, 47 (38.52 per cent), were from pus samples followed by 25 (20.49 per cent) from endotracheal tube aspirate. Out of 122 isolates, 87 (71.31 per cent) were multi-drug resistant of which 15 (12.29 per cent) were resistant to all drugs tested. CONCLUSION Acinetobacter infections associated with multi-drug resistant and pan-resistant strains have emerged as important nosocomial pathogens in our setting.

Chromobacterium violaceum: a potential nosocomial pathogen.

Chromobacterium violaceum is a motile gram-negative bacillus found as a saprophyte in soil and water.1,2 It is characterized by production of a purple pigment named violacein.2 It was first reported as a human pathogen in 1927 in Malaysia.1 Currently, it is recognized as a highly virulent opportunistic pathogen to humans, and several cases have been reported mostly from tropical and subtropical areas.1,2 Usual portal of entry of C violaceum is skin. The most common presentation in patients infected with C violaceum is sepsis, which is frequently life threatening.3 The other common manifestations include cutaneous involvement, followed by abscesses in liver, lungs, spleen, lymph nodes.1,3 Disseminated C violaceum infection has been reported to be associated with 60% to 80% mortality.1 C violaceum is frequently disregarded as a contaminant or misidentified. The awareness regarding this infection needs to be raised to a high degree because it is associated with high fatality rate.4 C violaceum has been commonly reported to be resistant to penicillins and cephalosporins. Therefore, in most cases of C violaceum infection, the initial empirical therapy based on penicillins and cephalosporins will not be effective and can result in increased mortality because of delay in initiation of appropriate therapy.1 However, it is usually susceptible to cotrimoxazole, fluoroquinolones, aminoglycosides, chloramphenicol, and carbapenems.1 C violaceum is able to survive under diverse environmental conditions because it produces several proteins contributing for its tolerance to antimicrobial compounds, heavy metals temperature, and acid.5 In our study, C violaceum was isolated 4 times from water samples collected under sterile precautions from operation theater taps of our hospital.Becausecontaminatedwater is thesourceof infectionandskin is the usual portal of entry of this organism, these isolates from the hospital environment can be a source of nosocomial infection.1,4 This can lead to fatal infection such as septicemia or deep abscess during preand postsurgical periods. Once infection is established, it should be diagnosed early, and prolonged antibiotic treatment is required.6 Regular surveillance of operation theater and critical care units for C violaceum in water samples is necessary to prevent mortality. Proper water treatment and safe water supply are also essential.