Comparison of four different methods for detection of biofilm formation by uropathogens.

Context: Urinary tract infection (UTI) is one of the most common infectious diseases encountered in clinical practice. Emerging resistance of the uropathogens to the antimicrobial agents due to biofilm formation is a matter of concern while treating symptomatic UTI. However, studies comparing different methods for detection of biofilm by uropathogens are scarce. Aims: To compare four different methods for detection of biofilm formation by uropathogens. Settings and Design: Prospective observational study conducted in a tertiary care hospital. Materials and Methods: Totally 300 isolates from urinary samples were analyzed for biofilm formation by four methods, that is, tissue culture plate (TCP) method, tube method (TM), Congo Red Agar (CRA) method and modified CRA (MCRA) method. Statistical Analysis: Chi‑square test was applied when two or more set of variables were compared. P < 0.05 considered as statistically significant. Considering TCP to be a gold standard method for our study we calculated other statistical parameters. Results: The rate of biofilm detection was 45.6%, 39.3% and 11% each by TCP, TM, CRA and MCRA methods, respectively. The difference between TCP and only CRA/MCRA was significant, but not that between TCP and TM. There was no difference in the rate of biofilm detection between CRA and MCRA in other isolates, but MCRA is superior to CRA for detection of the staphylococcal biofilm formation. Conclusions: TCP method is the ideal method for detection of bacterial biofilm formation by uropathogens. MCRA method is superior only to CRA for detection of staphylococcal biofilm formation.

Antimicrobial resistance in bacteria causing ventilator-associated pneumonia in a tertiary care hospital: one year prospective study.

Background: Ventilator-associated pneumonia (VAP) is the most common infection diagnosed in intensive care units (ICUs). The causative organisms of VAP vary among different populations and are increasingly associated with resistance against various antimicrobial agents. Objective of current study was to determine the bacteriological etiology of VAP, antimicrobial susceptibility pattern of the isolates and detect the presence of extended-spectrum -lactamases (ESBL), metallo β-lactamases (MBL) and AmpC -lactamases in multidrug resistant isolates causing VAP in the medical ICU. Methods: A prospective study was carried out over a year to know the various etiological agents of VAP and their drug susceptibility patterns. ESBL, MBL and AmpC -lactamases were detected in various isolates by combination disk method, imipenem-EDTA combined disk method and AmpC disk method respectively. Results: The majority of bacterial isolates causing VAP were found to be gram negative bacilli. Acinetobacter spp accounted for 34.28% of VAP cases followed by Pseudomonas aeruginosa which was responsible for 25.71% cases. Other gram negative bacilli isolated were Klebsiella pneumoniae, Citrobacter freundii, Enterobacter spp, and Escherichia coli. Out of the total 70 isolates, 67 (95.7%) were multidrug resistant and not even a single isolate was sensitive to all the drugs tested. Conclusions: Most of the pathogens causing VAP in our institute were multidrug resistant and in many isolates this resistance was due to production of ESBL, MBL, and AmpC β-latamases. Polymixin-B and colistin were found to be highly effective against multidrug resistant Acinetobacter spp and P. aeruginosa.

Study of virulence factors of uropathogenic Escherichia coli and its antibiotic susceptibility pattern.

Context: Urinary tract infection (UTI) is one of the most common nosocomial infections, caused by Escherichia coli. This study determined the presence of virulence factors in the organism and correlates it with the multi-drug resistance (MDR). Aims: The aim of the following study is to assess the virulence factors of uropathogenic E. coli and antibiotic susceptibility pattern. Settings and Design: This was a prospective study conducted in the Department of Microbiology in PT. B. D. Sharma, PGIMS, Rohtak. Subjects and Methods: The study was conducted over a period of 1 year. Urine samples received were processed as per standard microbiological procedures. Virulence factors such as hemolysin, hemagglutination, cell surface hydrophobicity, serum resistance, gelatinase and siderophore production were studied. The antimicrobial susceptibility was done as per Clinical and Laboratory Standard Institute Guidelines. Statistical Analysis Used: The data was analyzed by using SPSS(Statistical Package for the social sciences) IBM Corporation version 17.0. A two sided P ≤ 0.05 was considered to be signifi cant. Results: Hemolysin production was seen in 47.4%, hemagglutination in 74.8%, cell surface hydrophobicity in 61%, serum resistance in 59%, gelatinase in 67.5% and siderophore production in 88% isolates. Nitrofurantoin was found to be most effective followed by, gatifl oxacin and gentamicin. Twenty nine percent (29.62%) isolates were MDR. Conclusions: Therefore, the knowledge of virulence factors of E. coli and their antibiotic susceptibility pattern will help in better understanding of the organism and in the treatment of UTI.

Resistance Pattern of Escherichia coli Isolates from Surgical Wound Infections.

Background: Surgical wound infections, are common post-operative complications, that cause significant postoperative morbidity and mortality. Aim of the study: To isolate, identify and study the antimicrobial sensitivity of E. coli isolates from surgical wounds. Methodology: A total of 1088 pus samples were received over a period of one year from post-operative wounds. 313 isolates of E. coli were recovered and identified and antimicrobial sensitivity testing (AST) including extended spectrum beta lactamases (ESBL) detection was performed according to Clinical Laboratory Standard Institute (CLSI) guidelines. Results: E. coli accounted for 37.5% . ESBL production was detected in 22.0% of E. coli isolates. Conclusion: Our study shows that there is increased isolation rate of E. coli from post-operative wound infections. Hospital disinfection and treatment protocols should be practiced thoroughly and regularly monitored to control the incidence of wound infections.

Prevalence and Antibiotic Sensitivity Pattern of Bacteria Isolated from Nosocomial Infections in a Surgical Ward.

Background and Aims: Nosocomial infections among surgical patients are common and many are preventable. It is critical to understand microbiology of these infections in order to create appropriate strategies to reduce this risk. This study was planned to delineate the occurrence, microbiology and sensitivity pattern of such infections among surgical patients. Subject and Methods: Various from 130 patients admitted to the surgery ward were cultured, identified and antibiotic sensitivity was performed by standard methods. Results: From 130 patients, 146 isolates were recovered. Of these 140 (95.9%) were bacterial and six (4.1%) were of Candida spp. Most frequently observed nosocomial infections were SSIs (55.4%) followed by infections of urinary tract (28.4%), respiratory tract infections (10.8%) and bacteremia was observed in only 5.4% patients. The predominant pathogen isolated from polymicrobial episodes were E. coli, S. aureus, K. pneumoniae, A. baumanii and P. aeruginosa. Resistance to b-lactams was high and carbapenems were found to be most effective drugs against GNBs. Conclusions: Gramnegative organisms are the predominant pathogens causing infections in surgical patients. The increasing trend of resistance to b-lactams is posing a great problem. So for proper management of critically ill patients and patients undergoing various operative procedures and other medical interventions, hospital antibiotic policies need frequent revisions.

Evaluation of microbiocidal activity of superoxidized water on hospital isolates.

Background: Prevention of nosocomial infections, pre-operative and post-operative complications is directly linked with effective disinfection and decontamination. Microbial decontamination is the most serious challenge to the today's health care practice despite the abundance of disinfectants and chemicals as there are increasing reports of emergence of resistance to the action of commonly used disinfectants. There is a need to evaluate the efficacy of newer methods of asepsis for better patient management. Aim: This study was designed to evaluate the microbiocidal activity of superoxidized water (SOW) on common clinical isolates, ATCC strains, vegetative cells and spores of Bacillus subtilis. Materials and Methods: Bacterial suspensions were treated with SOW and deionized water (control). All the tubes were incubated at 37°C for 0.5, 2.5 and 5.0 min. The number of viable cells was counted. Results: All the clinical isolates and ATCC strains were killed within 0.5 min of exposure to the SOW. Vegetative cells and spores of B. subtilis were killed after 5.0 min. Conclusion: We conclude that SOW is an effective microbiocidal agent for routine hospital use.

Emergence of VRE and their antimicrobial sensitivity pattern in a tertiary care teaching hospital

During the last few years enterococci have emerged as an important cause of nosocomial and community acquired infection. They have acquired resistance to commonly used antibiotics including glycopeptides posing challenge to therapeutic options. The aim of this study was to investigate the prevalence and sensitivity of VRE to newer drugs. A total of 250 strains of E. faecalis were isolated using conventional scheme of Facklam and Collins. High level aminoglycoside resistance (HLAR) was detected by disc diffusion method using 120 ìg gentamicin disc and confirmed by agar dilution screen method. Screening for vancomycin resistance was done by disc diffusion and the agar screen method, and was further confirmed by broth dilution method for minimum inhibitory concentration (MIC). The strains which were resistant to vancomycin were further tested for sensitivity to newer and commonly available antibiotics. Maximum number of enterococcal isolates were recovered from urine (32.8 por cento) followed by blood (25.6 por cento) and pus (18.4 por cento). Penicillin (83.6 por cento) and cotrimoxazole (77.9 por cento) were found to be least effective drugs against the E. faecalis whereas; cefuroxime (76.8 por cento) and vancomycin (98 por cento) were most effective drugs in vitro. About two percent isolates of enterococci were resistant to vancomycin. All the VRE isolates were sensitive to quinupristin/dalfopristin. Linezolid and chloramphenicols were the two other in vitro effective drugs with 80 por cento sensitive isolates. MIC of all the VRE isolates was found to be in range of 64-512ìg/mL. So, quinupristin/dalfopristin can be used for infections caused by VRE. Continuous surveillance is necessary to detect early outbreak, and spread of VRE.

Detection of extended-spectrum beta-lactamase in Pseudomonas aeruginosa.

PURPOSE: The present study was designed to detect the extended-spectrum beta-lactamase (ESBL) production in Pseudomonas aeruginosa and to evaluate the susceptibility pattern. MATERIALS AND METHODS: One hundred forty-eight isolates of P. aeruginosa were analyzed for the presence of ESBL enzyme by double disc synergy test. Antibiotic sensitivity pattern of ESBL-positive P. aeruginosa was determined. RESULTS: Of the 148 isolates tested, 30 (20.27%) were found to be positive. Maximum ESBL production was found in sputum and tracheostomy swabs (28.57%), followed by pus (24.13%), urine (19.04%), cerebrospinal fluid (CSF) and other sterile body fluids (15.38%) and blood (7.14%). All the ESBL-producing P. aeruginosa isolates were multi-drug-resistant. Isolates were 100% sensitive to imipenem. Ofloxacin was the second most (70%) effective drug. CONCLUSION: From this study, we conclude the presence of ESBL-positive P. aeruginosa in our hospital. This has important implications as carbapenems remain the only choice of treatment for infections caused by these organisms. The control measures include judicious use of antibiotics and implementation of appropriate infection control measures to control the spread of these strains in the hospital.

Superior vena cava syndrome caused by pulmonary amoebic abscess.

Isolated pulmonary amoebiasis without involvement of liver and other systems is extremely rare. Its presentation with superior vena cava (SVC) syndrome is not well documented. The case of 38-year-old male who developed SVC syndrome due to a large pulmonary amoebic abscess, which initially mimicked a pulmonary neoplasm with distal lung abscess is presented here. Subsequent bacteriological examination of the aspirated pus and the sputum along with suggestive serology confirmed the diagnosis of pulmonary amoebic abscess.

Sensitivity pattern of Salmonella serotypes in Northern India

BACKGROUND: Enteric fever continues to be a major public health problem, especially in the developing countries of the tropics. We determined the incidence of Salmonella bloodstream infections and their antimicrobial resistance patterns from May to August in the years 1997-2001 in Haryana, a large state of India. The minimum inhibitory concentration (MIC) was also determined for 60 isolates of S. typhi to various commonly used antimicrobial agents. MATERIAL AND METHODS: Blood cultures of 6,956 patients (PUO/septicemia) were processed by standard procedures and the Salmonella spp. isolates were identified with specific antisera and with standard biochemical tests. Antimicrobial susceptibilities were determined by Stokes disc diffusion method. The MIC of 60 randomly isolated strains of S. typhi was determined by agar dilution method using Mueller Hinton Agar medium. RESULTS: Isolation rates of Salmonella spp. increased in 2000 and 2001. Multidrug resistance (MDR) in S. typhi had increased while in S. paratyphi it had decreased markedly. Ninety per cent chloramphenicol sensitivity was seen in S. typhi by MIC method. There was a decrease in the susceptibility to ciprofloxacin of S. typhi with MIC showing an upward trend. All S. typhi tested were sensitive to third generation cephalosporins and aminoglycosides with MIC well below the breakpoint. DISCUSSION: Our study indicates that MDR in S. typhi is on the rise in our area. There is also re-emergence of chloramphenicol sensitivity. Rising MIC values of ciprofloxacin may lead to prolonged treatment, delayed recovery or pose treatment failure. Thus, sensitivity pattern of causative organism must be sought before instituting appropriate therapy to prevent further emergence of drug resistance.

Bacteraemia in children.

OBJECTIVES: (i)To know the etiology of bacteraemia in children, (ii) To learn the antibiotic sensitivity pattern of the isolates. METHOD: Over the period of thirteen months 4,368 blood samples (for blood culture) were collected from children in the age group of 0 day-14 years, suspected of having fever and sepsis. Blood samples were collected for blood culture from each case. Organisms were isolated and identified by conventional methods. Antibiotic susceptibility for each isolate was determined by using modified Stokes method. RESULT: 1,001 cases (22.9%) were culture positive. Incidence of bacteraemia in neonates was 521(33.94%). Gram negative organisms were the most predominant isolates (88.8%). Commonest was Klebsiella 471 (47.1%) followed by Salmonella sp. 162 (16.2%) and Pseudomonas 80 (8%) whereas in gram positive, Staphylococcus aureus 76 (7.6%) was the most common. Maximum sensitivity was seen by sulbactum/cefaperazone combination-969 (98.2%) by all isolates. Linezolid 97 (99.0%) was the most sensitive drug for gram positive isolates. CONCLUSION: Gram negative multidrug resistant organisms were the main cause of septicemia in all the age groups. Therefore great caution is required in selection of antibiotic therapy.