Molecular and Clinical Features of Heterogeneous Vancomycin-Intermediate Staphylococcus aureus in Tertiary Care Hospitals in South India.

Objectives: This study aimed to detect heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) among methicillin-resistant S. aureus (MRSA) isolated from healthcare-associated infections and identify staphylococcal cassette chromosome mec (SCCmec) types. Methods: This study was conducted from February 2019 to March 2020 and included patients admitted in 4 tertiary care hospitals in Karnataka, India. Isolation and identification of MRSA were done using standard bacteriological methods. Antimicrobial susceptibility testing was done using Kirby-Bauer disc diffusion; macrolide-lincosamide-streptogramin B phenotypes were identified using the D test. The minimum inhibitory concentration (MIC) of vancomycin was determined using agar dilution. hVISA were confirmed by the modified population analysis profile-area under the curve test. SCCmec types and the Panton-Valentine leukocidin (pvl) gene were detected using multiplex polymerase chain reaction. Results: Of 220 MRSA stains, 14 (6.4%) were hVISA. None of the MRSA isolates was vancomycin-intermediate or -resistant and all hVISA were susceptible to linezolid and teicoplanin. The macrolide-streptogramin B phenotype was present in 42.9% of hVISA; 92.9% of the hVISA strains had vancomycin MIC in the range of 1-2 µg/mL. Majority of the hVISA and vancomycin-susceptible MRSA were isolated from patients with skin and soft tissue infections. SCCmec III and IV were present in 50% and 35.7% of hVISA, respectively; 14.3% of the hVISA harboured SCCmec V. Conclusion: The prevalence rate of hVISA among MRSA was 6.4%. Therefore, MRSA strains should be tested for hVISA before starting vancomycin treatment. None of the isolates was vancomycin-intermediate or -resistant and all the hVISA strains were susceptible to linezolid and teicoplanin. The majority of the hVISA were isolated from patients with skin and soft tissue infections and harboured SCCmec III and IV.

Validity of a CB-NAAT assay in diagnosing tuberculosis in comparison to culture: A study from an urban area of South India.

•CB-NAAT performance compared in 831 suspected pulmonary and extrapulmonary suspected cases.•The conventional stained smear and CB-NAAT results were compared to the MGIT culture.•Sensitivity and specificity of CB-NAAT was 84.43% and 94.93%.•The rapid results from CB-NAAT confirms its use in the tuberculosis diagnostic algorithm.•The benefits of disease diagnosis and prevention outweighs the price tag of the CB-NAAT tests.•This is more so for the resource poor countries where the burden of the disease is high.

Diagnostic and Prognostic Validity of Proadrenomedullin among Neonates with Sepsis in Tertiary Care Hospitals of Southern India.

INTRODUCTION: To evaluate Proadrenomedullin (Pro-ADM) as the diagnostic and prognostic marker in neonatal sepsis. MATERIALS AND METHODS: In this cross-sectional study, Pro-ADM levels were estimated in 54 neonates with clinical sepsis and positive sepsis screen (cases) and 54 controls without clinical sepsis. Repeat Pro-ADM levels were estimated after 72 hours in cases. Pro-ADM levels were compared with the clinical outcome. RESULTS AND DISCUSSION: Median Pro-ADM levels in cases were 31.8 (IQR: 27.8-39.4) pmol/ml which was significantly higher than controls 5.1 (IQR; 3.1-7.7) pmol/ml. From the constructed ROC curve, a value of 14.5 pmol/ml was taken as the cut-off for sepsis. Pro-ADM had 100% sensitivity, specificity, and positive predictive values (PPV) in detecting sepsis at 14.5 pmol/ml. Among cases, a decrease in Pro-ADM level by 10 pmol/ml was associated with 99% survival. Pro-ADM value of 35 pmol/ml had 100% specificity and PPV in predicting mortality. CONCLUSION: Pro-ADM can be used as a single biomarker for detecting neonatal sepsis, predicting clinical outcome and prognosis.

Antifungal effect of cow's urine distillate on Candida species.

BACKGROUND: Increase in resistance of Candida species, to routinely used antifungal agents has necessitated the quest for new drugs. Few studies have revealed that cow's urine can suppress the growth of pathogenic fungi. However there is no published report on antifungal effects of cow's urine on clinical Candida isolates. OBJECTIVE: The present study aims at exploring the antifungal potential of cow's urine on clinical isolates of Candida species. MATERIALS AND METHODS: In this in-vitro experimental study four standard strains and 37 clinical isolates of Candida species were tested for their susceptibility to amphotericin B, fluconazole and voriconazole, by disk diffusion method. Detection of MIC of cow's urine for the Candida isolates was done by agar dilution method using 20-50% concentration of cow's urine. RESULTS: Clinical isolates of Candida albicans n = 22 (59.5%) Candida glabrata n = 6 (16.2%), Candida tropicalis n = 3 (8.1%) and other Candida species n = 6 were tested for their antifungal susceptibility. Among them, 18.9% were resistant to voriconazole, 24.3% to amphotericin B and 35.1% to fluconazole. Statistically significant association was observed between susceptibility of voriconazole and that of cow's urine (p = 0.045). C. albicans ATCC14053, Candida parapsilosis ATCC22019 and 75.7% of clinical isolates of Candida were susceptible to cow's urine. CONCLUSION: Cow's urine distillate has concentration dependent inhibitory effect on Candida species and is effective on the isolates that are either resistant or sensitive to the routinely used antifungal agents.

Drug resistance & virulence determinants in clinical isolates of Enterococcus species.

BACKGROUND & OBJECTIVES: Enterococci are the leading cause of nosocomial infections, and are thus a persisting clinical problem globally. We undertook this study to determine the virulence factors and the antibiotic resistance in Enterococcus clinical isolates. METHODS: One hundred and fifty Enterococcus isolates obtained from various clinical specimens were speciated biochemically and subjected to antibiotic susceptibility testing using Kirby-Bauer disk diffusion method. Resistance to vancomycin was determined by using agar screen method. Haemolysin and gelatinase productions were detected using 5 per cent sheep blood agar and 12 per cent gelatin agar, respectively. RESULTS: Among the 150 Enterococcus isolates, 84 (56%) were E. faecalis. 51(34%) E. faecium, and 15 (10%) were other Enterococcus spp. Haemolysin production was seen among 123 (82%) isolates while 61 (40.6%) isolates produced gelatinase. Nearly 50 per cent of the isolates showed high level aminoglycoside resistance (HLAR). A total of 13 (8.6%) isolates showed vancomycin resistance, of which 11(7.3%) had an MIC >8 µg/ml. INTERPRETATION & CONCLUSIONS: Presence of VRE was found to be low among the isolates studied. However, occurrence of VRE along with HLAR calls for regular detection of vancomycin resistance promptly and accurately to recognize VRE colonization and infection. Early detection of VRE and HLAR along with their virulence trait will help in preventing the establishment and spread of multidrug resistant Enterococcus species.

Streptococcus pseudopneumoniae: an emerging respiratory tract pathogen.

BACKGROUND & OBJECTIVES: Streptococcus pseudopneumoniae a member of the Viridans Streptococci, is known to be associated with chronic obstructive pulmonary disease and respiratory tract infections (RTI). Very scanty information is available on the isolation of S. pseudopneumoniae from India. Hence, the present study was an attempt to isolate S. pseudopneumoniae from clinical samples and to study their drug resistance pattern. METHODS: Sputum samples (n=150) submitted to the microbiology laboratory for routine culture from patients clinically suspected to have lower respiratory tract infection were inoculated onto sheep blood agar and chocolate agar plates. Alpha haemolytic colonies were identified as S. pseudopneumoniae based on absence of capsule, bile solubility and optochin susceptibility in 5 per cent CO2 and ambient air. Disk diffusion method was used for antibiotic susceptibilily testing. RESULTS: Among the samples screened, 4 per cent showed the growth of only S. pseudopneumoniae. Other pathogens isolated were Streptococcus pneumoniae, Moraxella catarrhalis, Klebsiella spp., Enterococcus spp., Pseudomonas spp., Haemophilus influenzae, Staphylococcus aureus, Candida albicans. All the S. pseudopneumoniae isolates were resistant to erythromycin. INTERPRETATION & CONCLUSIONS: Our preliminary results showed presence of S. pseudopneumoniae in this part of the country and these were associated with RTI. Currently, most clinical laboratories report optochin susceptible isolates in 5 per cent CO2 as S. pneumoniae and the resistant ones are not further tested for susceptibility in ambient air. As a result, S. pseudopneumoniae may be missed out. Hence, performance of at least two tests, viz. optochin susceptibility with incubation in 5 per cent CO2 and ambient air along with bile solubility is necessary to differentiate S. pneumoniae from S. pseudopneumoniae.

Detection of shiga-toxigenic Escherichia coli (STEC) in diarrhoeagenic stool & meat samples in Mangalore, India.

BACKGROUND & OBJECTIVE: Shiga-toxigenic Escherichia coli (STEC) are causative agents of bloody diarrhoea, haemorrhagic colitis (HC) and haemolytic uraemic syndrome (HUS). Humans acquire infections primarily through contaminated beef. In India, STEC has not been implicated as a major cause of diarrhoea. Hence, isolation of STEC from diarrhoeagenic stool samples of patients and beef samples marketed through retail outlets was attempted in Mangalore, India. METHODS: Diarrhoeagenic stool samples (n = 192) and meat samples (n = 103) were screened for STEC, using conventional culture methods and polymerase chain reaction (PCR) from December 2003 to 2006 in the department of Microbiology, Kasturba Medical College, Mangalore. All the E. coli isolates were subjected to antibiotic susceptibility testing and serotyping. RESULTS: Of the 40 eae positive E. coli isolates from meat sample, one was positive for all the STEC genes, namely stx1, stx2, rfb O157 and EHEC hlyA. This isolate belonged to O157 serogroup. Of the 110 eae positive E. coli isolated from stool samples, two were positive for EHEC hlyA and belonged to serogroup O8 and one was positive for bfp gene and found to be of O6 serogroup. Among the 192 stool enrichment broths tested, 160 were positive for eae gene, of which two were EHEC hlyA positive and one was bfp gene positive. Among the 103 meat enrichment cultures, 90 were positive for eae gene and one among them was positive for all the STEC genes. INTERPRETATION & CONCLUSION: Our results showed a low incidence of STEC and high prevalence of eae positive E. coli other than STEC in stool and meat samples. A low positivity was observed for PCR performed directly on stool and meat samples. However, PCR on enrichment cultures gave better results. Since E. coli O157 was isolated and detected by PCR in one of the meat samples, this organism may be of public health significance. A study on a large sample may provide some answer.

Epidemiological shift, seasonal variation and antimicrobial susceptibility patterns among enteric fever pathogens in South India.

Between January 2005 and December 2006, a higher incidence of paratyphoid fever (53.8%) compared to typhoid fever (44.9%) has been observed at a tertiary hospital in South India. A definite seasonal pattern of incidence is seen in paratyphoid fever (peak incidence during October-December, i.e., post monsoon period) but not in typhoid fever. Decreased fluoroquinolone susceptibility is much higher in S. Paratyphi A (98.8%) as compared to S. Typhi (46.5%). These findings are of importance in therapeutic decision making, development of vaccination strategies and implementing public health measures for disease control.

Typing of Listeria monocytogenes isolates by random amplification of polymorphic DNA.

BACKGROUND & OBJECTIVES: Listeria monocytogenes is an important food-borne pathogen causing meningitis and septicaemia in newborns and immunocompromised persons, abortion and preterm labour in pregnant women. Though various methods are available for typing L. monocytogenes, RAPD analysis has been used for epidemiological purposes in developed countries due to its greater discriminating ability. However, as there are no published reports from India on the typing of L. monocytogenes by RAPD technique the present study was undertaken to type isolates of L. monocytogenes from clinical, food and veterinary samples. METHODS: Isolates of L. monocytogenes were subjected to RAPD using four decamer random primers R1, R2, R3 and R4. Amplified products were analysed by agarose gel electrophoresis. RESULTS: Eight strains of L. monocytogenes on RAPD analysis generated 4 distinct profiles each with R1 and R4 primers and 3 different profiles with R2 and R3 primers. The isolates from fish, clinical and veterinary samples showed different profiles with respect to each other. Isolate from flat fish (serovar 4) showed a different profile from that of clams (serovar 1). Two isolates from placenta (serovar 1) showed similar profiles and all the isolates from veterinary samples generated similar profiles. INTERPRETATION & CONCLUSION: RAPD analysis in the present study allowed discrimination of isolates among the same serotype but from different sources. Since RAPD is a rapid technique and offers greater discrimination of strains, this method may be used for typing L. monocytogenes in India.

Primary meningoencephalitis by Naegleria fowleri: first reported case from Mangalore, South India.

A fatal case of primary amebic meningoencephalitis (PAM) in a 5-month-old infant is described. The disease may have been contracted during bathing. The source of water was from an artificial well. The clinical presentation, the isolation of the ameba from the cerebrospinal fluid, the poor response to amphotericin B, and the ultimate fatal outcome are all consistent with the diagnosis of PAM. On the basis of its ability to grow at temperatures above 30 degrees C, the morphology of the trophozoite, and the presence of flagellate forms, the ameba was identified as Naegleria fowleri. Pathogenic N. fowleri amebae were recovered from samples of water from the well. To our knowledge this case represents the second case of PAM in an infant in the absence of the history of swimming.