Reba Kanungo

Correlation between biofilm production and multiple drug resistance in imipenem resistant clinical isolates of Acinetobacter baumannii

PURPOSE To study the qualitative and quantitative methods for the investigation of biofilm formation and to examine the correlation between biofilm and antibiotic resistance among the clinical isolates of Acinetobacter baumannii . We also verified the association between biofilm and presence of extended spectrum beta-lactamases, particularly, bla PER-1 . METHODS A total of 55 isolates were subjected to susceptibility testing by disc diffusion method for 13 clinically relevant antibiotics. Screening for biofilm production was done by both qualitative and quantitative methods through tube and microtitre plate assay respectively. The presence of bla PER-1 was checked by PCR. RESULTS A. baumannii isolates showed very high resistance (>75%) to imipenem, cephotaxime, amikacin and ciprofloxacin. Only cefoperazone, netillin and norfloxacin were found to be effective agents. Results of microtitre and tube methods were concordant with 34 isolates (62%) showing biofilm formation. Resistance to four antibiotics such as amikacin (82% vs. 17.6%, P < 0.001), cephotaxime (88% vs. 11%, P P < 0.001), ciprofloxacin (70% vs. 29%, P =0.005) and aztreonam (38% vs. 11%, P =0.039) was comparatively higher among biofilm producers than non-biofilm producers. Microtitre assay additionally detected 14 weakly adherent isolates. Only 11 isolates had bla PER-1 gene and among these two were strong biofilm producers, while remaining were weakly adherent isolates. CONCLUSION Microtitre plate method was found to be a more sensitive method for biofilm detection. This study demonstrates a high propensity among the clinical isolates of A. baumannii to form biofilm and a significant association of biofilms with multiple drug resistance. Presence of bla PER-1 appears to be more critical for cell adherence than for biofilm formation.

Phenotypic and genotypic assays for detecting the prevalence of metallo-β-lactamases in clinical isolates of Acinetobacter baumannii from a South Indian tertiary care hospital.

Nosocomial infections caused by Acinetobacter baumannii often prove difficult to treat owing to their multiple drug resistance. Carbapenems play a pivotal role in the management of severe Acinetobacter infections. However, reports of carbapenem resistance have been increasing alarmingly due to production of a variety of carbapenemases including metallo-beta-lactamases (MBLs). This study investigated by both phenotypic and genotypic assays the prevalence of MBLs in a total of 55 A. baumannii strains isolated from a South Indian tertiary care hospital. Random amplified polymorphic DNA (RAPD) genotyping and antimicrobial susceptibility testing for nine clinically relevant antibiotics was done for characterization of isolates. Phenotypic expression of MBLs was examined by a simple double disc synergy (DDS) test, and the presence of the most frequent MBL coding genes, bla(IMP1) and bla(VIM2), was checked by PCR. RAPD analysis generated six clusters of isolates and there was very little correlation between RAPD clusters and resistant profiles. Most of the isolates showed complete or high resistance to imipenem (100 %), meropenem (89 %), amikacin (80 %), cefotaxime (89 %) and ciprofloxacin (72 %). In addition, 44 % of isolates showed a high MIC level (> or =16 microg ml(-1)) for meropenem. Thirty-nine isolates (70.9 %) were positive for MBL production by the DDS test while bla(IMP1) gene amplification was seen only in 23 isolates (42 %). Interestingly, none of the isolates showed amplification of bla(VIM2). Further investigations on DDS-positive/PCR-negative isolates by spectrophotometric assay showed MBL activity in most of the isolates, suggesting involvement of other genes. The high incidence of isolates possessing MBL activity in the present study represents an emerging threat of complete resistance to carbapenems among Acinetobacter spp. in India.

Detection of pneumolysin and autolysin genes among antibiotic resistant Streptococcus pneumoniae in invasive infections.

PURPOSE To detect the presence of autolysin and pneumolysin genes among Streptococcus pneumoniae strains isolated from different disease entities among Indian patients. The study also attempted to determine antimicrobial susceptibility of the isolates. MATERIALS AND METHODS A total of 24 S. pneumoniae isolates were checked for the presence of lytA gene coding for autolysin and ply gene coding for pneumolysin using polymerase chain reaction (PCR). All the isolates were subjected to susceptibility testing by disc diffusion method for 10 different therapeutically relevant antibiotics. Minimum inhibition concentration (MIC) was determined using broth dilution method for ampicillin, penicillin and ciprofloxacin. RESULTS Eleven isolates from ocular infections and 13 isolates from different invasive diseases showed susceptibility to most of the antibiotics tested except chloramphenicol and ciprofloxacin. Fifty percentage of the isolates showed resistance to chloramphenicol and ciprofloxacin. A moderate level of resistance of 18% was noted for cefepime and ceftriaxone. Only 6% of resistance was observed for amoxicillin and ceftazidime. MIC levels ranged from 0.015 to 1 microg/mL for ampicillin and only one isolate had an MIC of 1 microg/mL. The MIC levels for penicillin ranged from 0.062 to 4 microg/mL, wherein nine isolates showed high levels of MICs ranging from 2 to 4 microg/mL. Six isolates had a very high resistance levels for ciprofloxacin with MIC ranging from 32-128 microg/mL. The presence of lytA was observed in 23 out of 24 isolates tested whereas only 17 isolates were positive for pneumolysin. Four ocular isolates and one isolate from ear infection were negative for pneumolysin. CONCLUSION Emerging resistance observed for cefepime and ceftriaxone might be due their increased and frequent usage nowadays. Presence of pneumolysin appears to be more critical for pathogenesis of invasive infections than the ocular infections. However, presence of lytA gene in all the isolates signifies that irrespective of site of isolation, kind of infection caused, autolysin is an obligate necessity for this organism.

Changing Trend in the Antibiotic Resistance Pattern of Pseudomonas Aeruginosa Isolated from Wound Swabs of Out-Patients and in-Patients of a Tertiary Care Hospital

CONTEXT Pseudomonas aeruginosa is the most common gram negative bacteria associated with nosocomial infections. Active surveillance of trends in antibiotic resistance of P. aeruginosa is necessary for the selection of appropriate antimicrobial agent for empirical therapy. AIM To assess the rates of antibiotic resistance and multidrug resistance among P. aeruginosa isolates and to observe the trend in its resistance pattern over a period of 5 years. MATERIALS AND METHODS Pseudomonas aeruginosa isolated from wound swabs during January to June 2007 and January to June 2012 were included in the study. Isolates were identified by conventional tests and antibiotic susceptibility was determined by disc diffusion method according to CLSI guidelines. RESULTS A total of 307 Pseudomonas aeruginosa isolates were included in the study. Among these isolates, 165 were isolated during Jan-June 2007 and 142 were isolated during Jan-June 2012. Among in-patients, there was a significant reduction in resistance rates of the isolates to ciprofloxacin (49% to 33%), ceftazidime (50% to 33%), meropenem (35% to 19%) and imipenem (28% to 14%) in 2012. Similarly, the rate of MDR Pseudomonas aeruginosa among the in-patients decreased from 37.9% in 2007 to 23.7% in 2012 (p value 0.0241). There was no significant difference in the resistance rates of the isolates from out-patients during the two study periods. CONCLUSION There was a significant decreasing trend in the resistance rates of the isolates to ciprofloxacin, ceftazidime, meropenem and imipenem. Reduction in the use of ciprofloxacin could be probable reason for the decreased resistance among P. aeruginosa isolates, which needs to be further investigated.

A Rare Case Report of Subcutaneous Phaeohyphomycotic Cyst Caused by Exophiala oligosperma in an Immunocompetent Host with Literature Review

We report a rare case of phaeohyphomycotic cyst in an immunocompetent patient caused by Exophiala oligosperma. This fungus is earlier known to cause infections in the immunocompromised. Identification of black fungi at species level is more challenging by conventional methods, and hence final identification of the fungi was based on sequencing of rDNA. The patient was managed with surgical excision. To the best of our knowledge, this is the first case report of E. oligosperma human infection from India.

Favorable outcome of amphotericin B treatment of zygomycotic necrotizing fascitis caused by Apophysomyces elegans

A 45‐year‐old man was referred from a primary health care center to our hospital in November 2005 with features of necrotizing fascitis of the right shoulder and upper back. He had been admitted to the previous hospital following an injury, sustained in an accident, while driving a tractor. He was treated for fracture of the right clavicle followed by wound debridement of the right shoulder at the health center. Examination of the wound in our hospital revealed a large, 15 × 15 cm, raw area over the upper back, extending to the right upper arm and shoulder. The wound was grossly infected with slough and purulent discharge. The margin of the wound was indurated. No other abnormality was detected on general examination, except for the fracture of the clavicle.

Pneumococcal Carriage at Age 2 Months Is Associated with Growth Deficits at Age 6 Months among Infants in South India

Nasopharyngeal colonization is the first step in the pathway to Streptococcus pneumoniae (Spn) infection, a leading cause of childhood morbidity and mortality. We investigated the effect of Spn colonization at ages 2 and 4 mo on growth at age 6 mo among 389 infants living in rural South India by using data from an Spn carriage study nested within a randomized, double-blind, placebo-controlled community trial designed to evaluate the impact of newborn vitamin A supplementation on Spn carriage in the first 6 mo of life. Primary outcomes were weight, length, and anthropometric indices of nutritional status. Growth data at age 6 mo were available for 84% (389 of 464) of infants in the Spn carriage study. Carriage at age 2 mo was associated with increased odds of stunting [OR: 3.07 (95% CI: 1.29, 7.36) P = 0.012] and lower weight [β: -266 g (95% CI: -527, -5) P = 0.045], length [β: -1.31 cm (95% CI: -2.32, -0.31) P = 0.010], and length-for-age Z scores [β: -0.59; (95% CI: -1.05, -0.13) P = 0.012] at age 6 mo. Spn carriage at age 4 mo did not affect growth. Carriage of invasive serotypes at age 2 mo was associated with decreases in mean weight [β: -289 g; (95% CI: -491, -106) P = 0.002] and length [β:-0.38 cm (95% CI: -1.49, -0.01) P = 0.047] at age 6 mo. Newborn vitamin A supplementation did not modify the association between Spn carriage and growth. Results suggest that pneumococcal carriage at age 2 mo is an independent risk factor for poor growth in young infants. Future studies need to clarify the role of Spn carriage on growth retardation in low-income countries.

A rare case of diphyllobothriasis from pondicherry, South India

Diphyllobothriasis is an intestinal parasitic infection caused by the ingestion of raw fresh-water fish containing the infectious larvae of Diphyllobothrium spp. This infection is uncommon in India. We report a case of diphyllobothriasis that occurred in Pondicherry, India, in a 5-year-old boy hailing from a fishing community. He attended the Pediatric OPD with spontaneous discharge of segments of the adult parasite. The segments (macroscopically and microscopically) were identified as those of Diphyllobothrium latum. The stool examination also revealed characteristic oval eggs.

Predebridement wound culture in open fractures does not predict postoperative wound infection: A pilot study

Background: There is confusion in the current literature regarding the value of obtaining predebridement wound cultures in the management of open fractures with several studies reporting contrasting results. We undertook a pilot study to determine the initial bacterial flora of open fractures in our environment and determine the correlation between subsequent wound infection if any, and the initial bacterial flora. Materials and Methods: Initial/predebridement wound swabs were obtained for 32 patients with open fractures. Patients underwent a debridement of the open wound and preliminary stabilization of fracture in the operating room within 24 h. Postdebridement wound cultures were obtained at 48 h and repeated subsequently, if indicated, during the follow-up period. The antibiotic therapy was modified based on the culture reports. Results: Initial wound swab culture showed bacterial contamination in 18 patients (56%); 14 patients (44%) developed an infection in the immediate postoperative period or during follow-up. Age, gender, co-morbid medical condition, delay in presentation, and grade of open fracture were not found to be predictors of postoperative infection. No patient had an infection with the same organism, which was present in the initial culture. Conclusion: The findings of this study suggest that the initial flora are not the infecting organisms in the open fracture wounds, and predebridement wound cultures have no value in predicting postdebridement wound infection.

Dengue virus infection: Need for appropriate laboratory tests for diagnosis and management of the condition in children during an outbreak.

BACKGROUND Outbreaks of dengue infection occur in several parts of India with clockwork precision closely related to changing seasons. Most recent outbreak in Puducherry occurred between October 2012 and January 2013, affected a sizable pediatric population. A prospective study was done to characterize the demographic, diagnostic and clinical profile of pediatric patients in a tertiary care center in Puducherry. MATERIALS AND METHODS Data of patients serologically positive for either dengue NS1 antigen or anti-dengue IgM antibodies were analyzed. Duration of fever, platelet count, complications, risk factors, morbidity and mortality were analyzed. RESULTS Among pediatric cases with fever who were screened for NS1/IgM antibody during the recent outbreak, 161 (37.5%) tested positive. NS1 was detected in 85% while 5.5% tested positive for IgM and 3% for IgG. Few (4.9%) tested positive for both NS1 and IgM and 1.2% were positive for both NS1 and IgG. The mean age was 6 years of which 9% were <1-year, the youngest being 1-month old infant. Mean duration of fever was 4 days. Vomiting was associated in 42% of cases. Thrombocytopenia (51%) and hepatomegaly (41%) were two major observations. Among the NS1 positive cases, 49% had thrombocytopenia. IgM alone and NS1 with IgM were associated with thrombocytopenia in 67% and 78% respectively. 14 children had complications of dengue shock syndrome, and four had dengue hemorrhagic fever. Totally, 22 of the children had platelet transfusion. There was no mortality reported among any of these children. CONCLUSION Combination of clinical findings and rapid NS1, IgM detection helped in confirming the diagnosis for appropriate management of dengue in children.