Characterization of Pseudomonas aeruginosa isolated from chronically infected children with cystic fibrosis in India

BACKGROUND: Pseudomonas aeruginosa is the leading cause of morbidity and mortality in patients with cystic fibrosis (CF). With chronicity of infection, the organism resides as a biofilm, shows multi-drug resistance, diversifies its colony morphology and becomes auxotrophic. The patients have been found to be colonized with multiple genotypes. The present work was carried out to characterize P. aeruginosa isolated from children with cystic fibrosis using phenotypic and genotypic methods. RESULTS: We studied 56 patients with CF attending the Pediatric Chest clinic at All India Institute of Medical Sciences, New Delhi, India during August 1998-August 2001. These patients were regularly followed up at the clinic. Out of 56 patients, 27 were culture positive for P. aeruginosa where 8 were chronically infected (Group1) and 19 were intermittently colonized with the organism (Group2). Patients under Group1 had significantly higher rates of hospitalization, death and colonization with different colony morphotypes (p < 0.05). The isolates from Group1 patients were the positive producers of extended spectrum beta lactamase. A total of 5 auxotrophs were recovered from 2 patients where one was chronically infected with P. aeruginosa and the other was a recently enrolled patient. The auxotrophs had the specific requirement for methionine and arginine. Molecular typing revealed 33 ERIC-PCR (E1-E33) and 5 PCR-ribotyping (P1-P5) patterns. By ERIC-PCR, 4 patients were colonized with 2–4 genotypes and the remaining 23 patients were colonized with the single genotype. CONCLUSION: With chronicity of infection, P. aeruginosa becomes multidrug resistant, diversifies its colony morphology, acquires mucoidity and shows auxotrophy for amino acids. The chronically infected patients can be colonized with multiple genotypes. Thus in a particular clinical set up, high index of suspicion should be there for diagnosis of CF patients so as to prevent the delay in diagnosis and management of CF patients

A case of bilateral empyema with pericardial effusion caused by streptococcus intermedius in an immunocompetent patient

Streptococcus intermedius, a member of the Streptococcus anginosus group and a part of the human oropharyngeal microbiome, is a&nbsp;recognised pathogen, mostly in immunocompromised patients or post gastrointestinal surgery, known to cause suppurative metastatic&nbsp;abscesses. We present an unusual case of bilateral empyema with pericardial effusion caused by Streptococcus intermedius in a&nbsp;healthy 30-year-old adult male patient with no known predisposing factors.This case report illustrates the ability of S. intermedius to&nbsp;produce life-threatening empyema in a healthy adult without any predisposing factors

Evaluation of susceptibility testing methods for polymyxin

SummaryBackgroundThe widespread resistance in Gram-negative bacteria has necessitated evaluation of the use of older antimicrobials such as polymyxins. In the present study we evaluated the different susceptibility testing methods for polymyxins B and E against Gram-negative bacteria using the new Clinical and Laboratory Standards Institute (CLSI) guidelines.MethodsThe susceptibility of 281 multidrug-resistant (MDR) Gram-negative bacteria (GNB) to polymyxin B was evaluated, comparing broth microdilution (BMD; reference method), agar dilution, E-test, and disk diffusion. Disk diffusion testing of polymyxin B was also performed against 723 MDR GNB.ResultsTwenty-four of 281 (8.5%) isolates were found to be resistant to polymyxin B by the reference BMD method. The rates of very major errors for agar dilution and E-test (for polymyxin B) were 0.7% and 1%, respectively, and those for disk diffusion (for polymyxin B and polymyxin E) were 1% and 0.7%, respectively. For the 257 isolates found sensitive by reference BMD, the rates of major errors by agar dilution and E-test (for polymyxin B) were 2.4% and 0%, respectively, and those for disk diffusion (polymyxin B and polymyxin E) were 0% and 0.7%, respectively. Twenty-six (3.6%) of the 723 Gram-negative isolates were resistant to polymyxin B by disk diffusion.ConclusionThe E-test and agar dilution methods showed good concordance with BMD. The disk diffusion method can be useful for initial screening in diagnostic laboratories

Evaluation of pulmonary infiltrates in patients with haematological malignancies using fibreoptic bronchoscopy and bronchoalveolar lavage

Background : Chest infection is the major cause of morbidity and mortality among patients with haematological malignancies. Conventional diagnostic methods - chest x-ray , blood and sputum culture have limited yield . We used fibreoptic bronchoscopy and bronchoalveolar lavage to evaluate nature of pulmonary infiltrates on chest x-ray. Patients and Methods : 25 patients with haematological malignancies with fever and pulmonary infiltrates were studied. Patients median age was 32 years, ranging from 16 to 65 years. There were 21 males and 4 females. Initial evaluation included - detailed physical examination including chest to see for any focus of infection. In all patients , base line blood counts (total and differential), chest x-ray and cultures from blood and other body fluids were taken before starting broad spectrum antibiotics . Those not responding over next 48-72 hours received gram positive coverage followed by amphotericin-B therapy . Patients with persistent fever and pulmonary infiltrates were subjected to fibre-optic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) and samples were collected for bacterial, fungal, AFB and viral studies. The findings were correlated with Chest x-ray and CT scan. Results The median time for FOB and BAL was 16 days (range, 3 to 32 days) after the clinical diagnosis of chest infection.. BAL fluid examination/culture grew microbial isolates in 21 of 25 patients (84%). Of thesebacteria alone were present in 10, fungi alone in 1 and polymicrobial isolates were seen in 10 patients (40%). Later included- a combination of bacteria and fungi - in 2 patients, bacteria and AFB - 6 and a combination of bacteria, AFB and fungi were seen in 2 patients. BAL changed the radiological diagnosis in 14 patients (56% diagnostic utility). Therapy was modified according to BAL results in 6 patients (therapeutic utility of 24 %). Concordance between radiological and BAL findings were found only in 5 patients (20%). FOB procedure was tolerated well, with mild and reversible complications (throat pain, transient hypoxia, tachycardia) in some patients. Conclusions: Infections are the main cause of pulmonary infiltrates in patients with haematological malignancies. Bacterial , fungal and mycobacterium tubercular organisms are the main isolates. Isolation of ESBL positive organisms and polymicrobial isolates suggest inclusion of appropriate initial empirical antibiotics in these patients to prevent development of resistant organisms. Higher frequency of AFB isolates (32%) was the surprising finding and need to be confirmed in future studies

A randomized, prospective open labeled study of oral amoxicillin-clavulanate and levofloxacin with intravenous ceftriaxone and amikacin in chemotherapy induced low risk febrile neutropenia

Background : We compared the efficacy of oral antibiotics with intravenous antibiotics in low risk febrile neutropenia. Design : A prospective, randomized study Methods: Between April 2004 - December 2005, 55 patients with low risk febrile neutropenia (expected neutropenia duration &#60; 7 days with no co-morbid features) between 15 and 75 years of age, were randomized to receive either oral amoxicillin-clavulanate 625mg twice daily and levofloxacin -500mg once daily OR intravenous (i.v.) ceftriaxone 2g and amikacin 15mg/kg once daily. Most patients were treated on out patient basis. The primary end point was response to therapy, defervescence of fever within 72 hours with improvement in any clinical manifestation of infection and no recurrence of fever for 48 hours without use of antipyretics. Use of growth factors was not permitted except in treatment failure. Results: A total of 64 febrile episodes were recorded (mean 1.20 ); 33 in the IV group and 31 in the oral antibiotics group. Both groups were equally matched for age (median 25 years in the IV group and 19 years in the oral group), gender, type of cancer, baseline absolute neutrophil count (median 200/cmm in both arms) and duration of neutropenia (5 days and 4 days in the IV and oral groups, respectively). A focus of infection was identified clinically in 15% of episodes and microbiologically in 11% of episodes; 57% of which were Gram positive organisms and the rest Gram negative. 72% in the IV arm and 77% in the oral arm responded to therapy (p=ns). One patient in IV group had one episode of seizure. Non-responding patients received second line IV antibiotics. There was no mortality in either group. Age &#62; 60 years, neutropenia lasting &#62; 7 days after the onset of fever and positive blood culture were predictors for lack of response to antibiotics on multivariate analysis. Conclusion: Oral antibiotics have comparable efficacy as IV antibiotics in the management of low risk febrile neutropenia

Multidrug Resistant Bacteria Causing Nosocomial Urinary Tract Infection in Neurology/ Neurosurgical Unit of a Tertiary Care Hospital

Introduction: Nosocomial infections with the multidrug resistant microorganisms remain the major concern in the hospitalized patients. Due to the underlying illness, trauma, various neurosurgeries, patients admitted to neurology/ neurosurgery units become more vulnerable to acquire device associated infections during their hospital stay. Objectives: To study the spectrum of uropathogens and their antimicrobial susceptibility pattern among patients admitted to the neurology/neurosurgery unit. Material and methods: A prospective study was conducted in the bacteriology laboratory, Department of Microbiology over a period of 4 months. Urine samples from the patients admitted to neurology and neurosurgical unit (ward and ICU) were processed and identified as per the standard protocol. The antimicrobial susceptibility testing was done using Kirby- Bauer method as per CLSI 2014 guideline. Results: Majority of the urinary isolates belonged to Enterobacteriaceae family in both ward and ICU patients. Among these, 91 out of 106 (86%) isolates in the ward and 43 out of 51 (84%) isolates in ICU were found to be multi drug resistant. Nitrofurantoin was observed to be resistant in more than 75% of both ward and ICU isolates. Conclusion: Majority of nosocomial uropathogens were found to be multidrug resistant. This study emphasizes the emergence of MDR isolates and nitrofurantoin resistance among the nosocomial uropathogens

Evaluation of urea loaded nanoclay biopolymer composites with Zn and P solubilizing microbes for nitrogen uptake and use efficiency in maize (Zea mays)-wheat (Triticum aestivum) cropping system

A field experiment was conducted during rainy (kharif) 2022 (July 2022–October 2022) and winter (rabi) 2022–23 (November 2022–March 2023) seasons at ICAR-Indian Agricultural Research Institute, New Delhi to evaluate a series of Zn and P solubilizing microbial culture enriched nanoclay biopolymer composite (NCBPC) loaded with nitrogenous fertilizer (urea) and the efficiency of the products for maize (Zea mays L.) and wheat (Triticum aestivum L.). Experiment consisted of 10 treatments, viz. T1, Control; T2, 100% N though urea; T3; T5; T7; and T9, 75% N as urea loaded NCBPC-A (prepared using acrylic acid + acrylamide + mango kernel flour) alone or along with P or Zn or P + Zn solubilizers; T4; T6; T8 and T10, 75% N as urea loaded NCBPC-B (prepared using acrylic acid + acrylamide + maize flour) alone or along with P or Zn or P + Zn solubilizers in a randomized block design (RBD) and replicated thrice. In both maize and wheat crop, highest grain (5.09 and 5.32 t/ha) and straw yield (6.56 and 7.45 t/ha), apparent N recovery (51.26 and 47.26%) and agronomic efficiency (12 and 13.3 kg grain yield obtained/kg N application) were obtained in treatment T10 followed by T9. In addition, total N uptake significantly enhanced by 20.1–28.4% in maize and 22.1–30.8% in wheat (T9 and T10); apparent nitrogen recovery (ANR) improved by 12.9–18.2 and 15.2–21.1% and agronomic efficiency (AE) triggered by 19.5–21.2 and 15.4–20.8% in maize and wheat crops respectively, under T9 and T10 treatments over standard urea fertilization (T2). Thus, the study concludes that, 25% N requirement could be cut down through application of 75% N (urea) loaded NCBPCs in conjunction with Zn or P or Zn + P solubilizing microbial culture as compared to sole urea application under maize-wheat cropping system

Clinical outcomes in typhoid fever: adverse impact of infection with nalidixic acid-resistant Salmonella typhi

BACKGROUND: Widespread use of fluoroquinolones has resulted in emergence of Salmonella typhi strains with decreased susceptibility to fluoroquinolones. These strains are identifiable by their nalidixic acid-resistance. We studied the impact of infection with nalidixic acid-resistant S. typhi (NARST) on clinical outcomes in patients with bacteriologically-confirmed typhoid fever. METHODS: Clinical and laboratory features, fever clearance time and complications were prospectively studied in patients with blood culture-proven typhoid fever, treated at a tertiary care hospital in north India, during the period from November 2001 to October 2003. Susceptibility to amoxycillin, co-trimoxazole, chloramphenicol, ciprofloxacin and ceftriaxone were tested by disc diffusion method. Minimum inhibitory concentrations (MIC) of ciprofloxacin and ceftriaxone were determined by E-test method. RESULTS: During a two-year period, 60 patients (age [mean ± SD]: 15 ± 9 years; males: 40 [67%]) were studied. All isolates were sensitive to ciprofloxacin and ceftriaxone by disc diffusion and MIC breakpoints. However, 11 patients had clinical failure of fluoroquinolone therapy. Infections with NARST isolates (47 [78%]) were significantly associated with longer duration of fever at presentation (median [IQR] 10 [7-15] vs. 4 [3-6] days; P = 0.000), higher frequency of hepatomegaly (57% vs. 15%; P = 0.021), higher levels of aspartate aminotransferase (121 [66–235] vs. 73 [44–119] IU/L; P = 0.033), and increased MIC of ciprofloxacin (0.37 ± 0.21 vs. 0.17 ± 0.14 μg/mL; P = 0.005), as compared to infections with nalidixic acid-susceptible isolates. All 11 patients with complications were infected with NARST isolates. Total duration of illness was significantly longer in patients who developed complications than in patients who did not (22 [14.8–32] vs. 12 [9.3–20.3] days; P = 0.011). Duration of prior antibiotic intake had a strong positive correlation with the duration of fever at presentation (r = 0.61; P = 0.000) as well as the total duration of illness (r = 0.53; P = 0.000). CONCLUSION: Typhoid fever caused by NARST infection is associated with poor clinical outcomes, probably due to delay in initiating appropriate antibiotic therapy. Fluoroquinolone breakpoints for S. typhi need to be redefined and fluoroquinolones should no longer be used as first-line therapy, if the prevalence of NARST is high

Comparative Proteomics of Inner Membrane Fraction from Carbapenem-Resistant Acinetobacter baumannii with a Reference Strain

Acinetobacter baumannii has been identified by the Infectious Diseases Society of America as one of the six pathogens that cause majority of hospital infections. Increased resistance of A. baumannii even to the latest generation of β-lactams like carbapenem is an immediate threat to mankind. As inner-membrane fraction plays a significant role in survival of A. baumannii, we investigated the inner-membrane fraction proteome of carbapenem-resistant strain of A. baumannii using Differential In-Gel Electrophoresis (DIGE) followed by DeCyder, Progenesis and LC-MS/MS analysis. We identified 19 over-expressed and 4 down-regulated proteins (fold change>2, p<0.05) in resistant strain as compared to reference strain. Some of the upregulated proteins in resistant strain and their association with carbapenem resistance in A. baumannii are: i) β-lactamases, AmpC and OXA-51: cleave and inactivate carbapenem ii) metabolic enzymes, ATP synthase, malate dehydrogenase and 2-oxoglutarate dehydrogenase: help in increased energy production for the survival and iii) elongation factor Tu and ribosomal proteins: help in the overall protein production. Further, entry of carbapenem perhaps is limited by controlled production of OmpW and low levels of surface antigen help to evade host defence mechanism in developing resistance in A. baumannii. Present results support a model for the importance of proteins of inner-membrane fraction and their synergistic effect in the mediation of resistance of A. baumannii to carbapenem