The seasonal abundance of Vibrio parahaemolyticus in oysters from two estuaries along the southwest coast of India was studied by colony hybridization using nonradioactive labeled oligonucleotide ...probes. The density of total V. parahaemolyticus bacteria was determined using a probe binding to the tlh (thermolabile hemolysin) gene, and the density of pathogenic V. parahaemolyticus bacteria was determined by using a probe binding to the tdh (thermostable direct hemolysin) gene. Furthermore, the prevalence of V. parahaemolyticus was studied by PCR amplification of the toxR, tdh, and trh genes. PCR was performed directly with oyster homogenates and also following enrichment in alkaline peptone water for 6 and 18 h. V. parahaemolyticus was detected in 93.87% of the samples, and the densities ranged from <10 to 10⁴ organisms per g. Pathogenic V. parahaemolyticus could be detected in 5 of 49 samples (10.2%) by colony hybridization using the tdh probe and in 3 of 49 samples (6.1%) by PCR. Isolates from one of the samples belonged to the pandemic serotype O3:K6. Twenty-nine of the 49 samples analyzed (59.3%) were positive as determined by PCR for the presence of the trh gene in the enrichment broth media. trh-positive V. parahaemolyticus was frequently found in oysters from India.
Bacterial pathogens as causative agents of infection constitute an alarming concern in the public health sector. In particular, bacteria with resistance to multiple antimicrobial agents can confound ...chemotherapeutic efficacy towards infectious diseases. Multidrug-resistant bacteria harbor various molecular and cellular mechanisms for antimicrobial resistance. These antimicrobial resistance mechanisms include active antimicrobial efflux, reduced drug entry into cells of pathogens, enzymatic metabolism of antimicrobial agents to inactive products, biofilm formation, altered drug targets, and protection of antimicrobial targets. These microbial systems represent suitable focuses for investigation to establish the means for their circumvention and to reestablish therapeutic effectiveness. This review briefly summarizes the various antimicrobial resistance mechanisms that are harbored within infectious bacteria.
Noroviruses are significant seafood-borne pathogens, commonly associated with the consumption of filter feeding bivalve molluscs. Here, we report the development of a reverse transcription polymerase ...chain reaction (RT-PCR) method using primers based on the RNA-dependent RNA polymerase gene of norovirus genogroup II (NoV GII). Samples of bivalves were processed for the concentration of virus and extraction of RNA, followed by reverse transcription PCR. A total of 50 molluscan shellfish samples were analyzed, of which 16 samples yielded positive amplifications of norovirus nucleic acid. The PCR method described here, involving a single set of primers, is useful for rapid screening of shellfish for NoV GII.
The community-associated methicillin-resistant
(CA-MRSA) has become increasingly prevalent in both community and hospital settings. The aim of this study was to determine the prevalence, molecular ...characteristics and antibiotic resistance profiles of CA-MRSA from community- and hospital-associated infections in a tertiary care hospital in Mangalore, India. Of 520
isolates, 362 were from inpatients (IP) and 158 were from outpatients (OP). One-hundred and thirty-two MRSA isolates obtained from 94 inpatients and 38 outpatients with complete clinical details were further analyzed. Of these, 81 (61.4%) were CA-MRSA (IP-47.9%, OP-94.7%) and 51 (38.6%) were HA-MRSA (IP-52.1%, OP-5.3%). All (100%) MRSA isolates were
gene positive. SCC
typing identified SCC
type IV (50.6%) and SCC
type V (66.7%) in CA-MRSA, while SCC
type I (41.2%), SCC
type III (19.6%), SCC
type IV (31.4%) and SCC
type V (25.5%) were detected in HA-MRSA isolates. The Panton-Valentine Leukocidin (PVL) gene was found in 70.4% of CA-MRSA, 43.1% of HA-MRSA with SCC
type IV and SCC
type V, and in 7.8% of true HA-MRSA. The antibiotic resistance profiles were determined by the disc diffusion method. Resistance to cefoxitin was used to identify MRSA. A significant difference
< 0.05) was observed between CA-MRSA and HA-MRSA with respect to resistance against cephalexin, cefotaxime, levofloxacin, linezolid and teicoplanin. CA-MRSA was predominantly resistant to ciprofloxacin (86.4%), erythromycin (66.7%), ofloxacin (49.4%), cefotaxime (44.4%), gentamicin (40.7%) and clindamycin (40.7%), while HA-MRSA showed resistance against ciprofloxacin (80.4%), erythromycin (80.1%), cefotaxime (70.6%),ofloxacin (58.8%), clindamycin (47.1%) and levofloxacin (41.2%).This study reports the prevalence of CA-MRSA in community and hospital settings and the possibility of multidrug-resistant CA-MRSA replacing HA-MRSA in hospitals. The observations from our study emphasize the need for urgent measures to manage this emerging crisis in healthcare settings.
With the advent of new molecular tools, new taxa of sulphur-oxidising bacteria (SOB) in diverse environments are being discovered. However, there is a significant gap of knowledge about the ecology ...and diversity of SOB in thermal springs. Here, the species diversity and phylogenetic affiliations of SOB were investigated using 16S rRNA and functional gene marker,
soxB
in thermal springs of Thane district of Maharashtra, India. Most SOB detected by 16S rDNA sequences belong to different operational taxonomic units (OTU’s):
Firmicutes
,
α
-,
β
-,
γ
-
Proteobacteria
and
Actinobacteria
with the dominance of first class. However, the sox
B
gene clone library sequences had shown affiliation with the
β
-,
γ
- and
α
-
Proteobacteria
.
β
-
Proteobacteria
-related sequences were dominant, with 53.3% clones belonging to genus
Hydrogenophaga
. The thiosulphate oxidation assay carried out for different isolates having distinct identity showed the mean sulphate-sulphur production from 117.86 ± 0.50 to 218.82 ± 2.56 mg SO
4
-S l
−1
after 9 days of incubation. Also, sulphur oxidation by the genus
Nitratireductor
,
Caldimonas
,
Geobacillus
,
Paenibacillus
,
Brevibacillus
,
Tristrella
and
Chelatococcus
has been reported for the first time that reveals ecological widening over which thiotrophs are distributed.
All serotypes of
are considered potentially pathogenic. However, the non-typhoidal
(NTS) serotypes vary considerably in terms of pathogenicity and the severity of infections. Although diverse ...serotypes of NTS have been reported from tropical seafood, their sources, physiological characteristics, and virulence potentials are not well understood. This study aimed to compare the physiological characteristics of selected serovars of
from seafood and investigate possible variations in the distribution of known genes within the pathogenicity islands.
A series of biochemical tests, including carbohydrate fermentation and amino acid decarboxylation tests were performed to physiologically compare the isolates. The genetic characterization with respect to putative virulence genes was done by screening for genes associated with
pathogenicity island (SPI) I-V, as well as the toxin- and prophage-associated genes by polymerase chain reaction.
Irrespective of serotypes, all the isolates uniformly harbored the five SPIs screened in this study. However, some virulence genes, such as the
,
, and
were not detected in all
isolates. The biochemical profiles of
serotypes were highly conserved except for variations in inositol fermentation and citrate utilization. All the isolates of this study were weak biofilm formers on polystyrene surfaces.
The pathogenicity profiles of environmental NTS isolates observed in this study suggest that they possess the virulence machinery necessary to cause human infections and therefore, urgent measures to contain
contamination of seafood are required to ensure the safety of consumers.
Co-infection with parasites and bacteria is of frequent occurrence in aquaculture, leads to growth impedance otherwise mortality in fish depending on the varying degree of a load of primary pathogen ...either parasite or bacteria. The mechanistic regulation of immune response during co-infection in fish has merely documented. The aim of this study was to determine the impact of co-infection with Aeromonas hydrophila at three exposure doses of Argulus sp. on the innate immune responses and antioxidative stress enzymes of goldfish (Carassius auratus). The experimental fish were randomly distributed into eight treatment groups viz. T1 (control group without Argulus and A. hydrophila infection), T2 (fish exposed to a sub-lethal dose of A. hydrophila), T3 (low Argulus-infested fish), T4 (T3 + sub-lethal dose of A. hydrophila), T5 (moderate Argulus-infested fish), T6 (T5 + sub-lethal dose of A. hydrophila), T7 (high Argulus-infested fish) and T8 (T7+ sub-lethal dose of A. hydrophila) in duplicates. After distributing experimental fish into their respective treatment group, A. hydrophila was injected to T2, T4, T6 and T8. After the bacterial challenge, four fish from each experimental group were randomly sampled on 24, 72, and 168 h and subjected to the hematological, innate immune parameters and enzymatic analysis. In the co-infection group T8, a high degree of enhanced pathogenicity of A. hydrophila was noticed with increased mortalities (84.2%) in comparison to other groups. The current study shows a declining pattern in RBC, PCV and Hb values with the degree of parasite infestation without co-infection groups. Moreover, in the T8 group, exposure of a sub-lethal dose of bacteria resulted in a drastic reduction of the recorded parameters. Furthermore, a decreased value for WBC, monocyte and neutrophil was found in higher parasite group co-infected with a sub-lethal dose of bacteria relative to other co-infected groups during the experimental period. Also, a decrease in innate immune parameters and antioxidative stress enzymes were observed in the T8 group compared to T7 and T2 groups throughout the trial period. These findings indicate that a rise in the dose of Argulus infection improves A. hydrophila colonization in goldfish and contributes to suppression of the innate immune system and increased mortality.
•Rate of mortality is more in co-infected group when compared to single pathogen group.•Dose dependent reduction in hematological parameters is observed among co-infected groups.•Co-infection with heavy dose of parasite impacts the innate immune parameters and antioxidant stress enzymes.•Dosage of pathogens during co-infection have role in regulating the innate immune system.
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