Nidhi Singla

Keratomycosis in and around Chandigarh: a five-year study from a north Indian tertiary care hospital.

To find out the prevalence and epidemiological features of keratomycosis in Chandigarh, the present study was carried out jointly by the Departments of Microbiology and Ophthalmology, Government Medical College Hospital, Chandigarh, over a period of 5 years from January 1999 to December 2003. Corneal scrapings were collected from a total of 154 suspected patients of keratomycosis and were processed and identified by standard laboratory techniques. The study revealed that a total of 64 cases (41.55%) were positive for fungal agents. Direct microscopy was positive in 52 cases (76.47%) and culture in 34 cases (53.12%). Most common fungal isolates were Aspergillus species 14 (41.18%), Fusarium species 8 (23.53%), Candida species 3 (8.82%), Curvularia species 2 (5.88%) and Bipolaris species 2 (5.88%). Thus, hyaline filamentous fungi were the most common etiological agents and mechanical trauma with vegetative matter was the most common predisposing factor. Males in age group of 21-50 years were more commonly affected.

Epidemiology of Candida blood stream infections: experience of a tertiary care centre in North India

INTRODUCTION Bloodstream infections due to Candida species are becoming a major cause of morbidity and mortality in hospitalized patients. The spectrum of candidemia has changed with the emergence of non-albicans Candida species, especially among critically ill patients. METHODOLOGY In a retrospective study (July 2009 to December 2009) on candidemia, various Candida species isolated from blood cultures were characterized and studied along with the determination of their antifungal susceptibility to amphotericin B, itraconazole, and fluconazole by Etest. Probable risk factors for patients in the intensive care unit (ICU) presenting with candidemia were also analyzed. RESULTS During the study period, a total of 4651 samples were received, out of which 468 samples (10.06%) were positive for growth of organisms: 441 (94.20%) aerobic bacterial pathogens and 27 (5.79%) Candida species. The most common Candida spp. isolate was C. tropicalis (40.8%) followed by C. albicans (29.6%), C. glabrata (18.5%) and others (11.1%). Out of the 27 Candida strains, 24 (88.9%) were isolated from patients treated in the ICU. Among these, association of previous use of broad-spectrum antibiotics in 22 patients (91.6%) and central line catheter insertion in 20 patients (83.3%) were found to be statistically significant as compared to non-candidemia patients (p <0.05). Antifungal susceptibility testing of the isolates revealed a lower level of drug resistance to amphotericin B (18.5% of the isolates) versus 77.8% resistance to fluconazole. CONCLUSION Rapid changes in the rate of infection, potential risk factors, and emergence of non-albicans Candida demand continued surveillance of this serious bloodstream fungal infection.

Candida Colonization in Urine Samples of ICU Patients: Determination of Etiology, Antifungal Susceptibility Testing and Evaluation of Associated Risk Factors

The presence of Candida in urine presents a therapeutic challenge for the physician as it is often asymptomatic, and management guidelines have not been clearly laid down on this issue. The presence of Candida in urine may represent contamination of clinical sample, actual colonization of the lower urinary tract or may be a true indicator of invasive infection of lower and/or upper urinary tract. In a clinical setting like the ICU, multiple risk factors for Candida colonization may be present in the same patient, thereby increasing the chances of candiduria, manifold. In the present study on 80 patients in ICU, high rate of Candida colonization (57.5%) was found in urine samples of ICU patients with C. tropicalis (57.3%) being the predominant species. We also isolated 8 strains of Trichosporon species, all of these presented as a mixed infection along with Candida species. Among the various risk factors studied, urinary catheterization and previous antibiotic therapy were identified as statistically significant (P value <0.05). The minimum inhibitory concentration of the isolates was determined for amphotericin B, fluconazole and itraconazole by E-test. Most of the isolates were susceptible to amphotericin B. The C. parapsilosis strains did not show any drug resistance; however, resistance to fluconazole was observed 18.6, 27.27, 50 and 25% in C. tropicalis, C. albicans, C. glabrata and Trichosporon species, respectively.

Evaluation of various methods for the detection of meticillin-resistant Staphylococcus aureus strains and susceptibility patterns.

Meticillin-resistant Staphylococcus aureus (MRSA) has been recognized as one of the major pathogens in hospital as well as community settings. In India, the mean isolation rate of MRSA is 20-40 % and many studies have suggested an escalating rate of infections caused by this organism. Despite pharmaceutical and technological advancement, infections caused by MRSA still remain difficult to diagnose. The present study was undertaken to compare five phenotypic methods for the detection of MRSA. This involved examining 200 isolates of S. aureus by oxacillin disc diffusion, cefoxitin disc diffusion, oxacillin screen agar test, the latex agglutination test and growth on CHROMagar. PCR for mecA gene detection was taken as the gold standard. It was found that 35 % of all S. aureus infections were caused by MRSA. The cefoxitin disc diffusion method, as recommended by the Clinical and Laboratory Standards Institute, was found to be a reliable method for MRSA detection but it should be supplemented with some other method like latex agglutination, CHROMagar or oxacillin screen agar testing so that no MRSA is missed. We recommend that along with cefoxitin disc diffusion, another method, preferably latex agglutination, should be routinely used in all hospitals to detect MRSA.

Outbreak of Salmonella Typhi enteric fever in sub-urban area of North India: A public health perspective

Outbreaks of enteric fever are a major health concern not only due to significant human morbidity and mortality but also fear of spread of multidrug resistant strains. We report an outbreak of enteric fever caused by Salmonella enterica serotype Typhi in a suburban area, in city Chandigarh of North India. Twenty-seven strains of S. typhi were isolated from blood cultures over a period of two weeks with 18 of these 27 patients residing in the same area. Maximum cases were in the age group 5-14 years (10 patients, 55.5%) while 4 (22.2%) cases were children under 5 years. All the strains showed similar resistogram being resistant to ampicillin and nalidixic acid, intermediate to ciprofloxacin and sensitive to chloramphenicol, ceftriaxone, cefotaxime, cotrimoxazole and azithromycin on disc diffusion testing. Minimum inhibitory concentration of ciprofloxacin was determined by agar dilution method and was found to be raised (≥ 2 μ g/mL). This nalidixic acid resistant S. typhi outbreak report warrants the necessity of implementing stringent sanitation practices in public health interest.

Saksenaea erythrospora, an emerging mucoralean fungus causing severe necrotizing skin and soft tissue infections – a study from a tertiary care hospital in north India*

Abstract Background: Saksenaea erythrospora is an emerging and recently described pathogenic fungus mainly causing invasive cutaneous infections. Globally, very few human cases, caused by S. erythrospora, have been reported. In India, among the genus Saksenaea, S. vasiformis was the only reported pathogenic species, until recently when a case of fungal rhinosinusitis was reported to be caused by S. erythrospora. We observed five human cases of necrotizing skin and soft tissue infections caused by S. erythrospora following traumatic implantation over 1-year study period. Methods: The study was conducted for a year observing the causative role of Saksenaea species in primary cutaneous necrotizing infections. The clinical entities were diagnosed by both microbiological and histopathological examination of the skin biopsies. The final identification of fungal strains was done by comparing internal transcribed spacer (ITS) and D1–D2 domains of the LSU (larger subunit) of the nuclear ribosomal RNA (rRNA) sequences with those of type strains of the different species of Saksenaea. Results: Out of total 23 cases of necrotizing skin and soft tissue infections, 5 were caused by S. erythrospora. Intramuscular injection into the gluteal region was the predisposing factor in four patients, while upper limb involvement, following medicated adhesive tape application, was seen in one patient. All patients were treated with liposomal amphotericin B (LAMB) along with extensive debridement of necrotic tissues. Four patients responded well however one died. Conclusion: Saksenaea erythrospora is an emerging mucoralean fungus isolated in India among patients undergoing inadvertent I/M injections entailing necrotizing fasciitis at the local site.

Determination of extended-spectrum β-lactamases and ampc production in uropathogenic isolates of Escherichia coli and susceptibility to fosfomycin

Background: Urinary tract infection due to Escherichia coli is one of the common problem in clinical practice. Various drug resistance mechanisms are making the bacteria resistant to higher group of drugs making the treatment options very limited. This study was undertaken to detect ESBLs and AmpC production in uropathogenic Escherichia coli isolates and to determine their antimicrobial susceptibility pattern with special reference to fosfomycin. Materials and Methods: A total number of 150 E. coli isolates were studied. ESBL detection was done by double disc synergy and CLSI method. AmpC screening was done using cefoxitin disc and confirmation was done using cefoxitin/cefoxitin-boronic acid discs. In AmpC positive isolates, ESBLs was detected by modifying CLSI method using boronic acid. Antimicrobial susceptibility pattern was determined following CLSI guidelines. Fosfomycin susceptibility was determined by disc diffusion and E-test methods. Results: ESBLs production was seen in 52.6% of isolates and AmpC production was seen in 8% of isolates. All AmpC producers were also found to be ESBLs positive. ESBLs positive isolates were found to be more drug resistant than ESBLs negative isolates. All the strains were found to be fosfomycin sensitive. Conclusions: ESBLs and AmpC producing isolates are becoming prevalent in E. coli isolates from community setting also. Amongst the oral drugs, no in-vitro resistance has been seen for fosfomycin making it a newer choice of drug (although not new) in future. An integrated approach to contain antimicrobial resistance should be actually the goal of present times.

Dengue in pregnancy: an under–reported illness, with special reference to other existing co–infections

OBJECTIVE To keep the level of awareness high as far as incidence of dengue among pregnant women is concerned. METHODS A total of 300 blood samples of patients with fever in pregnancy were received in the Department of Microbiology to rule out dengue infection (January 2011 to December 2012). The samples were put up for presence of dengue IgM antibodies and NS1Ag by ELISA. The patients who turned out to be positive for dengue serology were retrospectively analysed with respect to patients age, gestational age, clinical presentation, complications, platelet counts and maternal as well as foetal outcomes. RESULTS Out of 300 females tested, 22 (7.3%) were found positive for dengue infection during the said time period. Out of them 9 were positive for IgM antibodies against dengue and 10 were found to be positive for NS1Ag, while 3 were positive for both IgM antibody and NS1Ag. Five patients presented with dengue in first trimester, 9 in second trimester and 8 in third trimester. Two patients had coinfections. Patient with coinfection of dengue with malaria had intrauterine death of fetus at 37 weeks while the second one having dengue with typhoid had a preterm vaginal delivery at 35 weeks. CONCLUSIONS Establishing diagnosis of dengue infection in pregnancy is important for effective management by the obstetricians particularly the mode of delivery due to the potential risk of hemorrhage for both the mother and the newborn. Co-infections seen in endemic areas may be more common than usually reported.

Fusarium sacchari, a cause of mycotic keratitis among sugarcane farmers – a series of four cases from North India

The two most common filamentous fungi causing mycotic keratitis are Aspergillus and Fusarium spp. Around 70 Fusarium spp. are involved in causing human infections. In this study, four cases of keratitis in sugarcane farmers in India are being reported, caused by the sugar cane pathogen Fusarium sacchari, a species of the Fusarium fujikuroi species complex. Fusarial keratitis was established by potassium hydroxide/Calcofluor white wet mounts and fungal culture of corneal scrapings on conventional media. Final identification was done by genetic sequencing at CBS‐KNAW, Utrecht, The Netherlands. The antifungal susceptibility testing was done using broth microdilution method as per CLSI document M38‐A2. Four cases of F. sacchari keratitis were identified. Three of them had trauma with sugarcane leaves, whereas one sugarcane farmer reported trauma by vegetative matter. The morphological similarities among various Fusarium species warrant use of molecular methods for identification of cryptic species. A wide distribution of sugarcane farming could be the possible explanation for emergence of F. sacchari keratitis in India.

Occurrence and phenotypic detection of class A carbapenemases among Escherichia coli and Klebsiella pneumoniae blood isolates at a tertiary care center

BACKGROUND Resistance to carbapenems is a significant therapeutic threat. The increasing frequency of car bapenemase enzymes among Gram-negative bacilli makes their early detection and differentiation urgent. Carbapenemases belonging to Class A are most commonly produced by members of family Enterobacteriaceae and are inhibited to various degrees by clavulanic acid. The present study is aimed to determine the occurrence and phenotypic detection of Class A carbapenemases in Escherichia coli and Klebsiella pneumoniae blood isolates from septicemic patients. METHODS A total of 75 isolates of K. pneumoniae and 25 E. coli were screened for resistance to carbapenems by using meropenem and imipenem discs and meropenem E-test. Positive strains were then subjected to a modified Hodge test combined with carbapenemase inhibition tests to phenotypically detect and differentiate Class A serine carbapenemases from other classes of carbapenem hydrolyzing enzymes. RESULTS The screening test showing the number of isolates resistant to meropenem and imipenem were 41 and 35 for K. pneumoniae and nine and four for E. coli, respectively. A total of 25 (33.3%) K. pneumoniae isolates and two (8.0%) E. coli isolates were classified as Class A carbapenemase producers. Multidrug resistance with coexistence of extended spectrum-beta-lactamases occurred in 44.4% isolates. However, all of the isolates were susceptible to colistin, polymyxin B, and tigecycline by disc diffusion test. CONCLUSION We conclude from the present study that Class A carbapenemases appear to be the predominant cause of resistance to carbapenems in Enterobacteriaceae at our center and, thus, phenotypic detection based on simple methods should be employed routinely in clinical microbiology laboratories.