Polyhydroxyalkanoate biosynthesis and optimisation of thermophilic Geobacillus stearothermophilus strain K4E3_SPR_NPP.

Polyhydroxyalkanoates (PHA) can be used to combat the challenges associated with plastic because it is biodegradable and can be produced from renewable resources. Extremophiles are considered to be potential PHA producers. An initial screening for the PHA synthesizing ability of a thermophilic bacteria Geobacillus stearothermophilus strain K4E3_SPR_NPP was carried out using Sudan black B staining. Nile red viable colony staining was used to further verify that the isolates produced PHA. Crotonic acid assays were used to determine the concentrations of PHA. The bacteria showed 31% PHA accumulation per dry cell weight (PHA/DCW) when glucose was used as a carbon source for growth. The molecule was identified to be medium chain length PHA, A copolymer of PHA containing poly(3-hydroxybutyrate)-poly(3-hydroxyvalerate)-poly(3-hydroxyhexanoate) (PHB-PHV-PHHX) using 1H-NMR. Six carbon sources and four nitrogen sources were screened for the synthesis of maximum PHA content, of which lactose and ammonium nitrate showed 45% and 53% PHA/DCW respectively. The important factors in the experiment are identified using the Plackett-Burman design, and optimization is performed using the response surface method. Response surface methodology was used to optimize the three important factors, and the maximum biomass and PHA productions were discovered. Optimal concentrations yielded a maximum of 0.48 g/l biomass and 0.32 g/l PHA, measuring 66.66% PHA accumulation. Dairy industry effluent was employed for the synthesis of PHA, yielding 0.73 g/l biomass and 0.33 g/l PHA, measuring 45% PHA accumulation. These findings add credibility to the possibility of adopting thermophilic isolates for PHA production using low-cost substrates.

Identification of Quorum Quenching N-Acyl Homoserine Lactonases from Priestia aryabhattai J1D and Bacillus cereus G Isolated from the Rhizosphere.

Several pathogenic bacteria communicate using N-acyl homoserine lactone (AHL) as a quorum sensing (QS) molecule. The process of interfering with the QS system is known as quorum quenching (QQ), it is an effective tool to control QS-dependent virulence in pathogens. In the present study, rhizosphere bacterial isolates were screened for their ability to produce AHL lactonase enzyme as QQ molecules, which hydrolyses AHL signalling molecules and consequently blocks the QS system. Potent N-hexanoyl-l-homoserine lactone (C6HSL) hydrolytic QQ activity was detected in rhizosphere isolates namely Bacillus cereus G and Priestia aryabhattai J1D. The cell-free supernatant of the bacterial isolates indicated a reduction in biofilm formation in the human pathogens Vibrio cholerae, Pseudomonas aeruginosa, and Staphylococcus aureus without inhibiting cells, signifying their biocontrol property. Furthermore, liquid chromatography high resolution mass spectrometry analysis confirmed C6HSL hydrolytic activity by AHL lactonase produced by these rhizosphere isolates. Also, the aiiA homologous gene from the bacterial isolates showed similarity with the aiiA lactonase gene from Bacillus species, which was further confirmed by homology modelling. In silico structure analysis by comparing with the structure of Bacillus revealed the similarity in the active site, indicating the same degradation pattern. Based on available reported data, the present study indicates the first report of the presence of the aiiA lactonase gene in P. aryabhattai.

Concurrent Staphylococcus aureus bacteraemia in Plasmodium vivax malaria Infection: A report of two cases from western India.

Malaria and concurrent bacteraemia cases have been reported globally, mostly in association with Plasmodium falciparum malaria. In comparison, concurrent bacteraemia with Plasmodium vivax infected patients is reported rarely. However, considering unavailability of blood culture testing and widespread community and empirical antibiotic usage in low- and middle-income countries (LMICs), the frequency of bacteraemia and P. vivax co-infection may be much higher. We reported two cases of Staphylococcus aureus bacteraemia with P. vivax malaria infection. Both patients presented with high grade fever and chills with unremarkable systemic examination. Liver enzymes were raised along with inflammatory markers. Simultaneous diagnosis of methicillin sensitive S. aureus bacteraemia was done using automated blood culture, automated identification and sensitivity testing system. P. vivax malaria was confirmed with microscopy, antigen detection test and molecular test. Patients recovered uneventfully with antimalarial drugs and antibiotics.

Clinical Outcome of Patients on Ceftazidime-Avibactam and Combination Therapy in Carbapenem-resistant Enterobacteriaceae.

INTRODUCTION: Carbapenem-resistant Enterobacteriaceae (CRE) infections have a major effect on mortality as well as healthcare cost. Intensive care units (ICUs) in India, the epicenters for multidrug-resistant organisms, are facing a "postantibiotic era" because of very limited treatment options. A latest beta-lactam/beta-lactamase inhibitor ceftazidime-avibactam (CZA) new has a broad-spectrum antibacterial activity. CZA inhibits class-A and class-C beta-lactamases (as well Klebsiella pneumoniae carbapenemase (KPC)), along with some class-D carbapenems such as OXA-48-like enzymes that are seen in Enterobacteriaceae has recently become available. The current study aimed to assess and present the clinical response and patient outcome with infections due to CRE when treated with CZA alone or in combination with other drugs. MATERIALS AND METHODS: This retrospective study reviews the experience recorded and analyzed at two tertiary care centers including only adult patients with CRE infection who had received CZA alone or in combination with other antibiotics over a period between February 2019 and January 2020. RESULTS: In the period from February 2019 to January 2020, 119 culture-confirmed CRE isolates were tested for Xpert Carba-R. The predominant genetic mechanism was a combination of NDM+OXA-48 in 45/119 (37.81%). Total 40/57 patients received CZA+aztreonam alone or in combination with other drugs with an overall cure rate of 77.5% while the rest 17 received CZA alone in combination with the cure rate of 82.35%. 41/57 (71.92%) patients were in ICU. CONCLUSION: With overall mortality of 21%, these data suggest that CZA is a viable option for patients with CRE infections. To our knowledge, this is the first Indian study reporting CZA data in CRE infections. HOW TO CITE THIS ARTICLE: Nagvekar V, Shah A, Unadkat VP, Chavan A, Kohli R, Hodgar S, et al. Clinical Outcome of Patients on Ceftazidime-Avibactam and Combination Therapy in Carbapenem-resistant Enterobacteriaceae. Indian J Crit Care Med 2021;25(7):780-784.

Draft Genome Sequence of Geobacillus stearothermophilus Strain K4E3_SPR_NPP, Isolated from Kasol Hot Spring, Himachal Pradesh, India.

Geobacillus stearothermophilus strain K4E3_SPR_NPP is a thermophilic bacterium growing optimally at 70°C. Here, we present the draft genome sequence of Geobacillus stearothermophilus strain K4E3_SPR_NPP, which was isolated from Kasol Hot Spring (72.3°C), Himachal Pradesh, India (32°0'46.35″N, 77°19'0.4908″E).

Identification and Antifungal Drug Susceptibility Pattern of Candida auris in India.

Introduction: Candida auris has turned up as a multidrug-resistant nosocomial agent with outbreaks reported worldwide. The present study was conducted to evaluate the antifungal drug susceptibility pattern of C. auris. Methods: Isolates of C. auris were obtained from clinically suspected cases of candidemia from January 2019 to June 2021. Identification was done with matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) and panfungal DNA polymerase chain reaction (PCR), followed by sequencing. Antifungal susceptibility testing was performed with broth microdilution method. Results: Out of 50 isolates C. auris, 49 were identified by MALDI-TOF and one isolate was identified with panfungal DNA PCR followed by sequencing. For fluconazole, 84% (n = 42) isolates were found to be resistant and 16% (n = 8) isolates were susceptible (minimum inhibitory concentrations [MICs] range 0.5-16). Posaconazole exhibited potent activity, followed by itraconazole. For amphotericin B, only 6% (n = 3) isolates were resistant with MICs ≥2 µg/mL. Only 4% (n = 2) isolates exhibited resistance to caspofungin. No resistance was noted for micafungin and anidulafungin. One (2%) isolate was found to be panazole resistant. One (2%) isolate was resistant to fluconazole, amphotericin B, and caspofungin. Conclusion: Correct identification of C. auris can be obtained with the use of MALDI-TOF and sequencing methods. A small percentage of fluconazole-sensitive isolates are present. Although elevated MICs for amphotericin B and echinocandins are not generally observed, the possibility of resistance with the irrational use of these antifungal drugs cannot be denied. Pan azole-resistant and pan drug-resistant strains of C. auris are on rise.

Sensitivity Pattern Of Salmonella typhi And Paratyphi A Isolates To Chloramphenicol And Other Anti-Typhoid Drugs: An In Vitro Study.

PURPOSE: To investigate the antimicrobial sensitivity pattern of commonly prescribed antimicrobials (chloramphenicol, cefixime, ofloxacin, azithromycin, and ceftriaxone) against Salmonella enterica isolates. METHODS: Blood culture positive isolates of S. typhi and S. paratyphi A (N = 251) received at Metropolis Healthcare Limited (Mumbai, India) from four zones of India (North, South, West, and East) between April and August 2018 were tested for antimicrobial susceptibility by E-test method. Based on the minimum inhibitory concentration (MIC), the organism was categorized as sensitive, intermediate, and resistant against the respective antibiotics as per Clinical and Laboratory Standards Institute criteria 2018. RESULTS: Out of 251 Salmonella isolates, 192 (76.5%) were S. typhi and 59 (23.5%) were S. paratyphi A. All 251 (100%) Salmonella isolates were sensitive to cefixime, ceftriaxone, and azithromycin; 237/251 (94.4%) isolates to chloramphenicol and only 9/251 (3.6%) isolates were sensitive to ofloxacin. Based on average MIC and MIC breakpoints, Salmonella isolates were found to be sensitive to chloramphenicol (MIC: 3.89±6.94 µg/mL), cefixime (MIC: 0.13±0.11 µg/mL), azithromycin (MIC: 3.32±2.19 µg/mL), and ceftriaxone (MIC: 0.11±0.18 µg/mL) and resistant to ofloxacin (MIC: 2.95±6.06 µg/mL). More than 20% of Salmonella isolates had MICs of chloramphenicol as 1.5 µg/mL (27.85% isolates) and 2 µg/mL (29.53% isolates). CONCLUSION: Our study confirms the re­emergence of susceptibility of Salmonella isolates to chloramphenicol. Further, the concern about fluoroquinolone-decreased susceptibility as indicated by the intermediate susceptibility or resistance was reiterated in this study. Though cefixime, azithromycin, and ceftriaxone showed susceptibility, the possibility of antibiotic resistance with the irrational use of these antibiotics cannot be deterred. This study thus emphasizes the need for continuous evaluation and judicious use of antimicrobials, considering the ever-changing landscape.

Squamous Cell Carcinoma of Lower Lip Reconstructed with Bilateral Fan Flap.

The most frequent tumor related to the lips is the squamous cell carcinoma, with the lower lip more commonly involved than the upper lip. The pivotal risk factors having impact on the prognosis include size of the tumor, histopathological type and grade, perineural invasion, regional lymph node metastasis, and local recurrences. Management of lip cancer and reconstruction is a surgical challenge.

Preparation and characterization of silver nanoparticle loaded amorphous hydrogel of carboxymethylcellulose for infected wounds.

There is a growing demand for an appropriate and safe antimicrobial dressing to treat infected deep wounds. An amorphous gel formulation (SNP-CMC), containing silver nanoparticles (SNPs) and carboxymethylcellulose (CMC), was prepared in one step by the reduction of silver nitrate in situ. Spectrophotometric and microscopic analysis revealed that the SNPs were 7-21 nm in diameter. In simulated wound experiments, SNP-CMC gel was found to absorb 80.48 ± 4.69% w/w of saline and donate 17.43 ± 0.76% w/w of moisture within 24h indicating its dual fluid affinity. Cytocompatibility of the gel was assessed by proliferation studies with primary human skin cells. The antimicrobial activity studies showed that SNP-CMC containing 50 ppm of SNPs was effective against the growth of both Gram negative and Gram positive strains including methicillin-resistant Staphylococcus aureus (MRSA). These results indicate that SNP-CMC could be ideal for the treatment of deep infected wounds.