Mupirocin resistance in clinical isolates of staphylococci in a tertiary care centre in south India.

The present study was carried out to determine the rates of high-level and low-level mupirocin resistance in Staphylococcus spp. (MuH and MuL) in southern India. A prospective study was carried out on Staphylococcus spp. isolated for a period of three months in the microbiology laboratory of an 800-bedded tertiary care hospital. One hundred sixty-seven non-duplicate Staphylococcus spp. isolated from different specimens were tested for mupirocin susceptibility using 5 and 200 μg discs and by agar dilution. Rates of MuH were found to be two percent in methicillin-resistant Staphylococcus aureus (MRSA) and 28% in methicillin-resistant coagulase-negative Staphylococcus spp. (MRCoNS). MuL strains may be still treated with mupirocin, while MuH strains require other treatment options for eradication, making prior screening and differentiation important.

Evaluation and comparison of tests to detect methicillin resistant S. aureus.

Background and Objectives: Phenotypic methods for detection of methicillin resistant Staphylococcus aureus (MRSA) have been compared with the gold standard which, as of now, is by the detection of mecA gene and femA gene by polymerase chain reaction (PCR). Discrepancies in detection have an adverse effect on patient management, thereby highlighting the importance of accuracy in detection. Our study aims to evaluate the efficacy of cefoxitin disk diffusion test to detect MRSA and compare it with other phenotypic and molecular methods. Methodology; The study was conducted from June 2006 to December 2007 and included 610 Staphylococcus aureus (S. aureus) isolates obtained from clinical samples. All isolates were tested for MRSA using oxacillin screen agar plates with 6 µg/ml of oxacillin, cefoxitin disk diffusion using 30 µg disk and MIC of oxacillin. Selected isolates (55) were tested for presence of mecA gene and Fem A gene by PCR. Results: Out of 610 isolates, MRSA was identified in 34.09% by cefoxitin disk diffusion, 34.9% by oxacillin screen agar, 34.4% by MIC and 37.3% by oxacillin disk diffusion. When selected isolates were tested with molecular methods, the cefoxitin disk diffusion and PCR tests were comparable. Discussion: Prevalence of MRSA (34.09%) is quite high as in other studies. The oxacillin disk diffusion test which was used routinely earlier is showing low specificity (56%). Among all phenotypic methods, cefoxitin disk diffusion and PCR alone have similar sensitivity and specificity. Conclusion: Results of cefoxitin disk diffusion test are in concordance with the PCR for mecA gene. Thus, the test can be an alternative to PCR for detection of MRSA in resource constraint settings.

Prevalence of Methicillin Resistant Staphylococcus aureus (MRSA) Nasal carrier in Health Care Workers.

Methicillin resistance Staphylococcus aureus (MRSA) is an important nosocomial pathogen that causes severe morbidity and mortality worldwide. In recent years, nosocomial outbreaks of methicillin resistance Staphylococcus aureus (MRSA) has become a major infection control problem. Colonized employees are generally asymptomatic; they are a potential reservoir and disseminator of MRSA in hospitals. Nasal screening of health care workers (HCW) for MRSA is performed routinely in several countries, typically when more than one MRSA – colonized patient is identified in high risk ward, such as intensive care unit (ICU). This study was performed at PSG Hospitals to assess the prevalence of MRSA nasal colonization in health care workers and their sensitivity pattern. The prevalence of MRSA carriage among HCW’s was quite low (3.3%) in our institution. It has been recommended that, in case of epidemic in the hospital, all health care workers should be examined for MRSA colonization.

Assessment of pheromone response in biofilm forming clinical isolates of high level gentamicin resistant Enterococcus faecalis.

Twenty five clinical isolates of high level gentamicin resistant Enterococcus faecalis were tested for their biofilm formation and pheromone responsiveness. The biofilm assay was carried out using microtiter plate method. Two isolates out of the 25 (8%) were high biofilm formers and 19 (76%) and four (16%) isolates were moderate and weak biofilm formers respectively. All the isolates responded to pheromones of E. faecalis FA2-2 strain. On addition of pheromone producing E. faecalis FA2-2 strain to these isolates, seven of 19 (37%) moderate biofilm formers developed into high biofilm formers. Similarly one of the 4 (25%) weak biofilm formers developed into high level biofilm former. Twelve (48%) of the 25 isolates were transconjugated by cross streak method using gentamicin as selective marker. This proves that the genetic factor for gentamicin resistance is present in the pheromone responsive plasmid. Among these twelve transaconjugants, seven isolates and one isolate were high biofilm formers on addition of E. faecalis FA2-2 and prior to its addition respectively. Out of the total 25 isolates, eight transconjugants for gentamicin resistance could turn to high biofilm formers on addition of the pheromone producing strain. All the isolates were resistant to more than two antibiotics tested. All the isolates were sensitive to vancomycin. The results indicate the significance of this nosocomial pathogen in biofilm formation and the role of pheromone responding clinical isolates of E. faecalis in spread of multidrug resistance genes.

Evaluation of an enzyme-linked immunoassay for the detection of Cryptosporidium antigen in fecal specimens of HIV/AIDS patients.

Cryptosporidium parvum, a protozoan parasite, causes severe diarrhea in immunodeficient hosts like HIV/AIDS patients, leading to significant morbidity and mortality. Diagnosis of the Cryptosporidium oocyst in the stool of these patients by conventional microscopy is labor intensive and time consuming. Therefore, we planned to evaluate the usefulness of a stool ELISA test in detecting Cryptosporidial antigen. About 89 stool specimens obtained from HIV-seropositive patients with diarrhea were subjected to an ELISA test and modified acid-fast staining (gold standard), on both direct and formol ether-concentrated specimens. The prevalence of Cryptosporidial diarrhea was found to be 12.4% (11/89). Other enteric pathogens detected were Isospora belli (3), Giardial cyst (3), Entamoeba coli cyst (2), and Entamoeba histolytica cyst (1). Dual infection with Cryptosporidium and Isospora belli was seen in two patients. Concentration technique improved identification by microscopy. The sensitivity and specificity for stool ELISA were found to be 90.9% and 98.7% respectively. The results of stool ELISA indicate that this simple, rapid, reliable, and standardized immunoassay test is sensitive and specific for routine diagnosis and may be useful for large-scale epidemiological studies of Cryptosporidiosis.

Prevalence of multi and pan drug resistant Pseudomonas aeruginosa with respect to ESBL and MBL in a tertiary care hospital.

Multi drug resistant Pseudomonas aeruginosa (MDRPA) and pan drug resistant Pseudomonas aeruginosa (PDRPA) isolates in critically ill patients are often difficult to treat. Prevalence of MDRPA and their antibiotic profile was investigated to select an appropriate empirical therapy. Moreover lack of sufficient data on prevalence of PDRPA in tertiary care hospitals indicated the need for this study. Pseudomonas aeruginosa was isolated in 245 patients over a period of one and half years from various clinical materials and their antibiotic profile was determined. Minimum inhibitory concentration (MIC) for Imipenem and Meropenam was determined by broth dilution method. Phenotypic confirmation test and EDTA double disk synergy test was used to detect Extended spectrum a-lactamase (ESBL) and Metallo-a-lactamase (MBL) producers respectively. Out of 245 isolates, 54 strains (22 %) and 11 strains (4%) were found to be MDRPA and PDRPA respectively. Carbapenem resistant isolates showed MICs ranging from 16 to > 64 microg/ml. Thirty eight strains (15.5%) were ESBL producers and six (54.5%) among 11 PDRPA were MBL producers. Prevalence of MDR and PDR isolates of Pseudomonas aeruginosa was found to be 22% and 4% respectively, which is less compared to other studies. Majority of the PDRPA isolates were MBL producers which have propensity to spread to other bacteria.

Oerskovia turbata and Myroides species: rare isolates from a case of acalculus cholecystitis.

Here we report a case of acalculus cholecystitis, which presented with features of obstructive jaundice of one-week duration. The patient underwent cholecystectomy and bile grew a mixed culture of Oerskovia turbata and Myroides spp. Being a rare isolate, characteristic features of the former are described in this report. The patient recovered without any complication.

Subtenons infection by Dirofilaria repens.

Zoonotic filariasis caused by Dirofilaria repens, a parasite of carnivores occurs mainly in countries surrounding Mediterranean region. The infection occurs in and around eye among animal handlers through vector transmission. We are reporting a case of human Dirofilariasis affecting subtenons region in a 63 year-old woman from Coimbatore, South India. The purpose of this article is to review the clinical course and management of ocular Dirofilariasis.

Extended spectrum -lactamases in urinary isolates of escherichia coli and klebsiella pneumoniae - Prevalence and susceptibility pattern in a tertiary care hospital.

A total of 411 urinary isolates (353 Escherichia coli and 58 Klebsiella pneumoniae) were studied for extended spectrum -lactamase (ESBL) production by double disk approximation test and NCCLS confirmatory test. ESBL production was found to be 41% in E.coli and 40% in K.pneumoniae. Fourteen percent and 12% of ESBL producers showed false susceptibility to ceftazidime and cefotaxime in routine susceptibility testing. The susceptibility of ESBL producers to imipenem, nitrofurantoin and amikacin was found to be 100%, 89% and 86% respectively. A high degree of associated resistance to gentamicin, co-trimoxazole and quinolones was found in ESBL producers. Majority of ESBL producers was detected among patients admitted in medical ICU and surgery ward.

Isolation, characterisation and antibiogram of Enterococci from clinical samples.

During a one year study 2955 clinical specimens of pus, urine, wound swabs, blood cultures, discharges from fistula, peritoneal aspiration fluid, CSF and sputum were processed to find out the prevalence rate of enterococci. One hundred isolates (3.38%) of Enterococci were obtained which were speciated by conventional methods. The highest incidence was from isolates of urine (43%), pus (40%), wound swabs (11%), and the least incidence was noted in discharges from fistula (2%), blood cultures (2%) and peritoneal aspiration fluid (2%). 98% were Enterococci and among these 88% of the isolates were Enterococcus faecalis. Antibiogram of the isolates were done by Standard disc diffusion method and Vancomycin sensitivity was found to be 95%.

An atypical presentation of salmonella typhi - A case report.

Breast abscess due to Salmonella typhi is an extremely rare occurrence. A lady with a lump in the left breast was diagnosed to have a fibroadenoma and was subjected to a surgical procedure. She was found to have an abscess due to Salmonella typhi as confirmed by conventional bacteriological methods. She was treated with ciprofloxacin and responded favourably.

Vancomycin sensitivity and KOH string test as an alternative to gram staining of bacteria.

Two hundred and eighteen bacterial isolates obtained from various clinical samples were subjected to Gram stain by conventional method. For all the isolates potassium hydroxide (KOH) string test and sensitivity to vancomycin were done. Gram positive bacteria showed 100% sensitivity to vancomycin as also 100% negativity for string test. Of the gram negative bacteria, 99.42% were resistant to vancomycin while 98.85% were positive for the string test. KOH and vancomycin tests are simple, inexpensive and can be used in addition to Gram staining for rapid identification of bacterial cultures.