Detection Of Virulence Genes Research Articles

High Incidence of Metastatic Infections in Panton-Valentine Leucocidin-Negative, Community-Acquired Methicillin-Resistant Staphylococcus aureus Bacteremia: An 11-Year Retrospective Study in Japan.

Panton-Valentine leucocidin (PVL)-negative community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) was originally disseminated in Japan and has since replaced healthcare-associated MRSA (HA-MRSA). However, the clinical characteristics of CA-MRSA bacteremia (CA-MRSAB) compared with those of HA-MRSA bacteremia (HA-MRSAB) are unknown. We aim to clarify differences and investigate associations between the clinical manifestations and virulence genes associated with plasma-biofilm formation in PVL-negative CA-MRSA. From 2011 to 2021, when CA-MRSA dramatically replaced HA-MRSA, 79 MRSA strains were collected from blood cultures and analyzed via SCCmec typing and targeted virulence gene (lukSF-PV, cna, and fnbB) detection. The incidence of metastatic infection was significantly higher in CA-MRSAB than in HA-MRSAB. PVL genes were all negative, although cna and fnbB were positive in 55.6% (20/36) and 50% (18/36) of CA-MRSA strains and 3.7% (1/27) and 7.4% (2/27) of HA-MRSA strains, respectively. cna and fnbB carriage were not associated with the development of metastatic infections in MRSAB; however, the bacteremia duration was significantly longer in CA-MRSAB harboring cna. CA-MRSAB may be more likely to cause metastatic infections than HA-MRSAB. Since CA-MRSA is dominant in Japan, suspected metastatic infection foci should be identified by computed tomography, magnetic resonance imaging, and echocardiography when treating MRSAB.

Molecular detection of virulence genes in pseudomonas aeruginosa isolated from different clinical infections

Objective: To isolate pseudomonas aeruginosa from different clinical specimens, and to detect virulence factors.Method: The cross-sectional study was conducted at Al-Zharr Hospital and private clinics in Kut city of Wasit provincein Iraq from October 15, 2021, to April 30, 2022, and comprised samples obtained from different patient sites, such aswound swabs, ear swabs, urine samples, burn swabs and respiratory tract swabs. The samples were subjected tomolecular testing using, among other tools, polymerase chain reaction. The isolates were cultured on different media,such as blood agar, MacConkey agar and cetrimide agar, and were further diagnosed by biochemical testing. Datawas analysed using SPSS 20.Results:Of the 212 samples, there were 70(33%) wound swabs, 53(25%) ear swabs, 41(19.3%) urine samples, 33(15.6%)burn swabs and 15(7%) respiratory tract swabs. Pseudomonas aeruginosa was identified in 54(25.47%) isolates viaculture-based characterisation. All 54(100%) isolates were positive for mexR and toxA on polymerase chain reaction,44(81.48%) were positive for exoU gene, 43(79.62%) for exoT gene, 36 (66.66) for exoT gen, 35(64.81%) for plcH, geneand 14(25.92 %) for exoS gene.Conclusions: Wound swabs were found to be the most common site for pseudomonas aeruginosa, followed by earswabs and urine samples.Keywords: Pseudomonas aeruginosa, Virulence, Agar, Cetrimonium, Virulence, Burns, Polymerase chain reaction, DNA.

Molecular epidemiology and antibiotic resistance of Pseudomonas aeruginosa isolated from blood in a hospital in Shandong Province from 2014 to 2021

Objective: To identify the antibiotic resistance, virulence genes, and sequence types of Pseudomonas aeruginosa (P. aeruginosa) strains isolated from blood. Methods: From November 2014 to December 2021, a total of 94 nonrepetitive P. aeruginosa isolates were obtained from blood samples of patients at the First Affiliated Hospital of Shandong First Medical University in Shandong Province, China. The bacteria were identified using matrix-assisted laser desorption ionization time of flight mass spectrometry. Antibiotic resistance of the P. aeruginosa isolates was detected using Vitek 2 Compact system. Polymerase chain reaction (PCR) was conducted for the 18 virulence genes, and multi locus sequence typing (MLST) was performed to identify the sequence types of the P. aeruginosa strains. The resistance rates and distributions of virulence genes between carbapenem resistant pseudomonas aeruginosa (CRPA) and carbapenem susceptible pseudomonas aeruginosa (CSPA) isolates were compared using the Chi-square test. Results: Among 94 P. aeruginosa isolates, 19 (20.2%) isolates were found to be multidrug resistant (MDR) bacteria, of which 17 were CRPA isolates and 2 were CSPA isolates. All strains contained more than 10 virulence genes. Except for exoU gene, the detection rate of other genes was above 83%. MLST analysis revealed a total of 66 different STs, including 59 existing STs and 7 novel STs. Among them, ST244 (n=11, 11.7%) and ST270 (n=7, 7.4%) were the dominant STs. Although these two types of isolates harbored the same virulence genes, the resistance rates to carbapenem were different. 54.5% (6/11) ST244 isolates were CRPA but all 7 ST270 isolates were CSPA. Conclusion: Although the resistance rates of P. aeruginosa strains isolated from blood were at a low level, some MDR and CRPA isolates were detected. As the high virulence gene detection rates and genetic diversity were found for P. aeruginosa strains isolated from blood, close attention should be paid to avoid transmission and outbreaks.

Prevalence, drug resistance, molecular typing and comparative genomics analysis of MRSA strains from a tertiary A hospital in Shanxi Province, China.

Staphylococcus aureus (S. aureus) is an important zoonotic pathogen that causes a high incidence rate and mortality worldwide. This study investigated the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains in a tertiary A hospital in Shanxi Province, China, in order to determine the major epidemic clones as well as their antibiotic resistance and virulence characteristics. A total of 212 S. aureus strains were collected in this hospital, and were subjected to antimicrobial susceptibility testing, detection of virulence genes, resistance genes, and efflux pump genes. Among them, 38 MRSA strains were further subjected to detection of biofilm genes, assessment of biofilm formation ability, MLST, spa typing, SCCmec typing, and phylogenetic analysis. The majority of S. aureus strains came from the neonatology department, with secretions and purulent fluid being the main source of samples. The strains showed high resistance to penicillin (98.11%), erythromycin (64.62%) and clindamycin (59.91%), while being sensitive to vancomycin and linezolid. The detection rates of efflux pump genes and resistance genes were high, and there was a significant correlation between resistance gene types and phenotypes, with mecA showing a close correlation with oxacillin. The detection rates of virulence genes and the toxin gene profiles of MSSA and MRSA strains showed significant differences. And the detection rate of biofilm genes in MRSA strains was relatively high, with 13.16% of MRSA strains showing strong biofilm formation ability. The most common epidemic clone of MRSA was ST59-SCCmecIV-t437, followed by ST59-SCCmecV-t437. The former had a higher detection rate of resistance genes and a stronger biofilm formation ability, while the latter had a higher positive rate for pvl gene and stronger pathogenicity, making it more likely to cause systemic infections. Phylogenetic analysis showed that all MRSA strains in this study clustered into three major branches, with distinct differences in antibiotic resistance and virulence characteristics among the branches. ST59-MRSA strains from different species showed consistency and inter-species transmission, but there were differences among ST59-MRSA strains from different geographical locations. In general, most MSSA and MRSA strains exhibited multidrug resistance and carried multiple resistance genes, virulence genes, and biofilm formation genes, warranting further research to elucidate the mechanisms of drug resistance and pathogenesis.

Molecular and biological Study of Colibacillosis Susceptibility in broiler

This study was aimed to Detection of virulence genes(rfbE) It was carried in College of Veterinary Medicine at Baghdad university, During a time span of November (2021) to March (2022). (100) samples were collected from diarrheal chicken . 100 chicks were used in the present study, One day old chicks were weighed (Average of chick weight was 160 gm±2) then transferred to the poultry house. Chicks in wards that were divided by wood barriers. Diagnosis of bacterial colonies were first done by the bacteriological methods. From (100) fecal samples of diarrheal cases of chicken , 90(90%) isolates were Escherichia coli.In the present study using vitek 2 compact system and Api 20 Escherichia coli. for the identification isolated bacteria. PCR technique was used to Detection of virulence genes(rfbE) ,The result for rfbE gene in this study was showed that this gene was detected in(60) isolates of (90) samples of chicken observed carried the rfbE gene which represent (67%).

Molecular typing and characterization of Staphylococcus aureus isolates from burn wound infections in Fujian, China.

Staphylococcus aureus (S. aureus) is the most common causative agent of burn wound infection, that often leads to high morbidity and mortality. However, there is not enough knowledge about the molecular epidemiology and antimicrobial susceptibility of S. aureus isolates from burn wound infections in Fujian, China. Between 2016 and 2021, 90 S. aureus isolates were collected from burn wound infections in Fujian, China, including 59 methicillin-resistant (MRSA) strains and 31 methicillin-susceptible (MSSA) strains. These were investigated for molecular characteristics, virulence genes, biofilms, and antimicrobial susceptibility. All the isolates were genotyped by multilocus sequence typing (MLST), spa typing, agr typing, and SCCmec typing. Conventional PCR was performed for the detection of virulence genes. Biofilm formation capacity was assessed by tissue culture plate assay (TCP). The antimicrobial susceptibility of the isolates was evaluated using the dilution method. In total, 37 sequence types (ST) and 34 Staphylococcal protein A (spa) types (including a new type named spa-t20720) were identified based on multilocus sequence typing (MLST) and spa typing, respectively. CC8-ST239-t030-agrI-SCCmecIII (57.6%,34/59) and CC7-ST7-t091-agrI (16.1%, 5/31) represented the main clone of MRSA and MSSA isolates, respectively. Antibiotic susceptibility testing identified a significant difference in resistance rates between ST239 and non-ST239 isolates (p < 0.05). Twelve virulence genes were detected, of which the most common were icaA and icaD (both 100%), followed by icaB and icaC (both 96.7%), icaR (95.6%), lukED (81.1%), lukAB (62.2%), pvl (50%), hlgBC (26.7%), and eta (4.4%). Moreover, lukAB, hlgBC, agrI, and agrIII were significantly correlated with burn severity (p < 0.05). MRSA isolates were less likely, compared with MSSA isolates, to carry pvl, lukAB, and hlgBC (p < 0.05). A new spa type, t20720, was identified that contains pvl, lukED, lukAB, hlgBC, icaA, icaB, icaC, icaD, and icaR genes and has strong biofilm formation ability. CC8-ST239-t030-agrI-SCCmecIII and CC7-ST-7-t091-agrI were the prevalent molecular signatures of MRSA and MSSA isolates from burn wound infections in Fujian, China, respectively. The newly identified spa-t20720 isolate, which carries a wide range of virulence genes and has strong biofilm formation ability, requires special clinical attention.

Serratia marcescens isolated from newborn meningitis in the Iraqi city of Diwaniyah: Molecular characterization

Our study was conducted to detect virulence genes in Serratia marcescens. It has many virulence genes that cause nosocomal infections in immunocompromised persons and neonates. A total of 24/100 (24%) S. marcescens were obtained from neonates suffering from meningitis, and they were identified using culture characteristics biochemical- tests and confirmed by Polymerase chain reaction (PCR) technique, using the 16S rRNA gene. All virulence factors, including the fimA gene that encodes type-1 fimbria, the bsmB gene that encodes exo polysaccharide production, and ampC that encodes ß-lactamase enzymes, were done using the PCR technique. The results revealed that S. marcescens isolates have 16S rRNA gene at the percentage (100%), fimA gene at the percentage (54%), bsmB gene at the percentage (71%) and ampC gene at the percentage (100%). Finally, the DNA sequencing of (fimA, bsmB, and ampC genes) was done using a DNA sequencer technique to determine the sequence of nucleotides. The results revealed the similarities of the genes in local isolates of S. marcescens (98%) with S. marcescens isolates globally registered on the NCBI-Genbank website. Keywords: fimA gene, bsmB gene, ampC gene, Serratia marcescens, DNA sequences.

Detection of virulence genes among Staphylococcus saprophyticus isolated from women with urinary tract infections: first report from Iran

ObjectiveThe purpose of the present study was to investigate the biofilm production, and the presence of virulence genes and biochemical characteristics among the S. saprophyticus clinical isolates. A total of 35 clinical isolates of S. saprophyticus were collected from patients referred to several hospitals. By the crystal violet staining method, the capability of biofilm formation was performed. The genes associated with surface of S. saprophyticus were investigated by the PCR-sequencing techniques. Hemagglutination and lipase activity assays were also performed.ResultsThe results of crystal violet staining assay showed that 32 isolates (91%) form biofilm. Moreover, seven (20%), 13 (37%), and 12(34%) isolates were categorized as weak, moderate, and strong biofilm producers, respectively. virulence genes including UafA, Aas and Ssp had an overall prevalence of 88%, 91% and 80%, respectively. None of the isolates exhibited lipolytic activities. Regarding hemagglutination properties, only 11 (31%) isolates demonstrated hemagglutination of sheep erythrocytes. The results of this study indicate a high prevalence of UafA and Aas genes that can enhance the pathogenicity of S. saprophyticus, and Identification and better understanding of the functions of these genes can be used for therapeutic purposes. Maybe in the future we will be switch to anti-adhesion therapy because of drug resistance.

Multiplex PCR detection of antibiotic resistance and virulence genes in multidrug-resistant Staphylococcus aureus isolated from chickens, humans, rodents, and soil in Northern Tanzania

Staphylococcus aureus (S. aureus) is a zoonotic pathogen with public health and veterinary importance. We investigated the presence of antibiotic resistance genes (ARGs) and virulence genes (VGs) in 57 multidrug-resistant (MDR) S. aureus isolated from humans (n=17), chickens (n=14), rodents (n=13), and soil (n=13) using multiplex PCR. Overall, the distribution of ARGs revealed that the tetK was found in 18/57 (31.6%), mecA in 16/57 (28.1%), tetL in 5/57 (8.9%), and ermC in 1/57 (1.8%), while ermA and tetM were not detected. For VGs, the clfB was found in 6/57 (10.5 %), coa in 8/57 (14.0%), clfA in 3/57 (5.3%), hlg in 1/57 (1.8%), ebpS in 2/57 (3.5%), fnbB in 2/57 (3.5%), luk-PV in 6/57 (10.5%) and tst in 1/57 (1.8%). Resistance genes (tetK and mecA) and virulence determinants (clfB, coa, and luk-PV) were common in all sample sources, while tst, hlg, and fnbB were specific to human, chicken, and rodent isolates, respectively. Erythromycin phenotypic resistance results correlated with the presence of ermC (r=0.42), tetL (r=0.98), and mecA (r=0.51), while tetracycline resistance correlated with tetL (r=1.00) and mecA (r=0.57) genes and methicillin resistance correlated with mecA (r=0.55) and tetL (r=0.98) genes. Positive correlations were noted between ARG (ermC) and VGs; clfA (r=0.57), hlg (r=1.00), and clfB (r=0.43), and between tetK and clfB (r=0.39); tetK and coa (r=0.36) genes. Principal component analysis (PCA) shows that tetL, ermC, and mecA contributed to tetracycline, erythromycin, and methicillin resistance, respectively. The widespread presence of resistance and virulence genes, often in combination, among MDR S. aureus in isolates from humans, chicken, rodents, and soil samples require comprehensive One-Health interventions.

Antimicrobial Resistance, Biofilm Formation, and Virulence Determinants in Enterococcus faecalis Isolated from Cultured and Wild Fish.

Fish has always been an integral part of Bengali cuisine and economy. Fish could also be a potential reservoir of pathogens. This study aimed to inquisite the distribution of virulence, biofilm formation, and antimicrobial resistance of Enterococcus faecalis isolated from wild and cultivated fish in Bangladesh. A total of 132 koi fish (Anabas scandens) and catfish (Heteropneustes fossilis) were collected from different markets in the Mymensingh district and analyzed to detect E. faecalis. E. faecalis was detected by conventional culture and polymerase chain reaction (PCR), followed by the detection of virulence genes by PCR. Antibiotic susceptibility was determined using the disk diffusion method, and biofilm-forming ability was investigated by crystal violet microtiter plate (CVMP) methods. A total of 47 wild and 40 cultured fish samples were confirmed positive for E. faecalis by PCR. The CVMP method revealed four per cent of isolates from cultured fish as strong biofilm formers, but no strong producers were found from the wild fish. In the PCR test, 45% of the isolates from the wild and cultivated fish samples were found to be positive for at least one biofilm-producing virulence gene, where agg, ace, gelE, pil, and fsrC genes were detected in 80, 95, 100, 93, and 100% of the isolates, respectively. Many of the isolates from both types of samples were multidrug resistant (MDR) (73% in local fish and 100% in cultured fish), with 100% resistance to erythromycin, linezolid, penicillin, and rifampicin in E. faecalis from cultured fish and 73.08, 69.23, 69.23, and 76.92%, respectively, in E. faecalis from wild fish. This study shows that E. faecalis from wild fish have a higher frequency of virulence genes and biofilm-forming genes than cultivated fish. However, compared to wild fish, cultured fish were found to carry E. faecalis that was more highly multidrug resistant. Present findings suggest that both wild and cultured fish could be potential sources for MDR E. faecalis, having potential public health implications.

Resistance Profiles and Virulence Determinants in Biofilm-Forming Enterococcus faecium Isolated from Raw Seafood in Bangladesh.

Pathogenic, antibiotic-resistant, and biofilm-forming bacteria can be transferred to humans through the consumption of contaminated seafood. The present study was carried out to determine antibiotic resistance profiles and virulence determinants in biofilm-forming Enterococcus faecium isolated from seafood in Bangladesh. A total of 150 seafood samples, including shrimp (n = 50), crabs (n = 25), and marine fish (n = 75), were screened using cultural, staining, biochemical, polymerase chain reaction (PCR), Congo red (CR), and disk diffusion (DD) assays. In PCR, E. faecium was detected in 27.3% (41/150; CI95% 20.8; 34.9) of samples, where marine fish (34.7%, CI95% 24.9; 45.9) had the highest prevalence (p < 0.05) compared to crabs (32%, CI95% 17.2; 51.6) and shrimp (14%, CI95% 7.0; 26.1). Thirty-two (78.1%, CI95% 63.3; 88.0) of the E. faecium isolates were determined to be biofilm formers in the CR test, where 43.9% (18/41, CI95% 29.9; 59.0) and 34.2% (14/41, CI95% 21.6; 49.5) of the isolates were strong and intermediate biofilm formers, respectively. In PCR, virulence genes, i.e., pil (100%), ace (92.7%), agg (68.3%), fsrA (65.9%), gelE (63.4%), sprE (53.7%), fsrB (51.2%), and fsrC (43.9%), were detected in E. faecium isolates. All the E. faecium isolates were phenotypically resistant to ≥3 antimicrobial categories and ≥3 antibiotics, including WHO-classified reserve antibiotics linezolid (70.7%) and fosfomycin (19.5%). Moreover, the multiple antibiotic resistance index ranged up to 0.8, showing resistance to ten antibiotics and eight antibiotic classes. In this study, the prevalence of virulence genes and antibiotic resistance was significantly greater (p < 0.05) in strong biofilm-forming E. faecium strains as compared to strains with intermediate and non-biofilm-forming abilities. As far as we know, this study, for the first time in Bangladesh, determined antibiotic resistance and detected virulence genes in biofilm-forming E. faecium isolated from seafood samples. The data from this study could play a significant role in evaluating potential health hazards linked to the ingestion of uncooked or minimally processed seafood.

Serotypes, virulence and antimicrobial susceptibility of Group B Streptococci isolated from infections in non-pregnant adults in Malaysia

This is a cross-sectional study describing on Group B Streptococcus (GBS) serotypes, virulence gene distribution and antimicrobial susceptibility in non-pregnant adults from two major hospitals on East-coast Malaysia. The patients’ clinical information was reviewed, while serotyping and virulence gene detection for the GBS isolates (n = 75) were conducted by PCR. GBS serotypes III and Ia were the most common, followed by serotypes II and IV. The majority of GBS (n = 65; 86.7%) presented with virulence genes such as cylE, scpB, lmb, hylE and bca. Skin and soft tissue infection (SSTI) (n = 50; 66.7%) were the most common clinical diagnosis, with 90% of those diagnosed had underlying diabetes mellitus (DM). GBS serotype Ia and the virulence genes cylE and scpB were common in SSTI. Good sensitivity towards penicillin, erythromycin and clindamycin were observed.

Detection of Virulence Genes Stx1, Stx2, eae A and hly A in E.coli Isolated from Local Minced Meat

The current study included the investigation of E. coli bacteria in random samples of ground meat, the detection of virulence genes in isolates, and the study of isolates resistance to some widely used antibiotics. Twenty-four samples of minced meat were collected to isolate and identify E. coli bacteria by phenotypic, microscopic characteristics and traditional biochemical tests were done. Antibiotic susceptibility tests, genomes of isolates were extracted, the virulence factors Stx1, Stx2, eae A and hly A were investigated by multiplex PCR technique. 7 isolates showed Colonies with a metallic green luster on EMB medium, gram negative, rod shaped bacteria, facultative anaerobic bacteria, positive for indole, methyl red and catalase tests, and negative for Fox Proscore, urease and oxidase tests. All isolates were containing hly A gene, 6 isolates were containing the virulence gene Stx1, 5 isolates containing were eae A gene and 4 isolates were containing Stx2 gene. The results shown a high resistance of E. coli isolates to all types of antibiotics used, as all isolates were possessed multiple antibiotic resistance.

Detection of Pathogenicity Island-encoding Virulence Genes of Staphylococcus aureus Isolated from Various Clinical Sources

Detection of Pathogenicity Island-encoding Virulence Genes of Staphylococcus aureus Isolated from Various Clinical Sources

Characteristics of Extended-Spectrum β-Lactamase-Producing Escherichia coli Derived from Food and Humans in Northern Xinjiang, China.

This study aimed to investigate the drug resistance, molecular characteristics, and genetic relationship of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolated from food and human stool samples in northern Xinjiang. From 2015 to 2016, a total of 431 samples (meats and vegetables) were collected from retail markets and supermarkets located in the regions of Urumqi, Shihezi, and Kuitun in Xinjiang, China, and 20 human stool samples from the Shihezi Hospital. The PCR method was used to detect E. coli, and the presence of ESBL-producing E. coli was confirmed using the K-B disk diffusion confirmatory method. The susceptibility to ESBL-producing E. coli was tested by the microdilution broth method, and the minimum inhibitory concentration was determined. PCR was used to detect the resistance and virulence genes of ESBL-producing E. coli, and phylogenetics, plasmid replicon typing, screening of three integrons, and multilocus sequence typing (MLST) were performed. The results showed that 127 E. coli strains (15 human stool and 112 food samples) were isolated. Out of the 127 E. coli strains, 38 strains (6 human stool and 32 food 34 samples) of ESBL-producing E. coli were identified through screening. These 38 strains showed resistance to cefotaxime (94.74%) and cefepime (94.74%), and were sensitive to meropenem (0.00%). The most detected resistance genes were blaTEM (47.37%), and the most detected virulence genes were fimH (97.73%), ompA (97.73%), hlyE (97.73%), and crl (97.37%). The isolates belonged to phylogroups B1 (42.11%), C (23.68%), and A (21.05%). Among the plasmid replicon subtypes, IncFIB was the main type (42.11%). The integrons detected were of the first type (47.37%) and the third type (26.32%). The 38 E. coli strains had 19 different sequence-type (ST) strains. These 38 strains of ESBL-producing E. coli were analyzed using MLST and STs are varied.

Comparison of prevalence, resistance, biofilm-forming ability and virulence between carbapenem-non-susceptible and carbepenem-susceptible Enterobacter cloacae complex in clusters

This study aimed to explore the differences of prevalence, resistance, biofilm, and virulence between carbapenem nonsusceptible and susceptible Enterobacter cloacae complex (ECC) in different clusters. Ninety-one carbapenem nonsusceptible isolates and an equal number of susceptible isolates as well as their clinical information were collected from a university teaching hospital in China. The strains were divided into different clusters according to the analysis based on hsp60. Agar dilution method was used to determine the MICs of common antibiotics. Crystal violet assay was used to measure biofilm-forming ability. Galleria mellonella infection model and PCR of virulence genes were used to evaluate the virulence. The isolates were divided into 12 clusters based on the hsp60 analysis. Cluster VIII accounted for a predominant and higher proportion of carbapenem nonsusceptible isolates than the other clusters. The same clusters exhibited different resistance rates in carbapenem nonsusceptible and susceptible isolates. Moreover, carbapenem nonsusceptible isolates carried fewer virulence genes than susceptible isolates, and cluster II in carbapenem nonsusceptible isolates didn't carry the detected virulence genes. The virulence of clusters I, III, VIII, and IX was significantly different between the nonsusceptible and susceptible isolates, as evaluated using the Galleria mellonella infection model. Cluster VIII accounted for a predominant and higher proportion as well as higher resistance, biofilm formation ability, and pathogenicity in carbapenem nonsusceptible isolates than the other clusters. This finding indicated the necessity to identify subgroups of ECC and provide better advice and guidance for the use of carbapenem.

Detecting Enteric Pathogens in Low-Risk Drinking Water in Dhaka, Bangladesh: An Assessment of the WHO Water Safety Categories.

The microbiological quality of water is usually assessed by fecal coliform bacteria, and the presence of E. coli as an indicator of fecal contamination is widely recommended by international guidelines. This study aimed to assess the prevalence of diarrheagenic pathogens, in both public and personal domain water sources and examine the reliance on the WHO drinking water risk assessment guidelines. This study was conducted in a low-income urban community in Dhaka, Bangladesh between September 2014 and October 2015. Polymerase chain reaction (PCR) was used to detect the marker and virulence genes of Escherichia coli, Vibrio cholerae, Salmonella species, and Campylobacter species, and the culture method was employed for the quantitative assessment of E. coli. According to the WHO guidelines, 48% of the public domain source water and 21% of the personal domain point-of-drinking water were classified in the low-risk group, i.e., 0 CFU of E. coli/100 mL. However, when using PCR, we detected pathogens in 39% (14/36) of the point-of-drinking water samples and 65% (74/114) of the public domain water source samples classified in the low-risk group. Our study showed that relying solely on E. coli detection as a measure of water quality may overlook the presence of other pathogens in the drinking water. In addition to the culture-based method, the detection of virulence genes by PCR should also be considered to add more scrutiny to the detection of diverse types of pathogens.

Molecular Detection of Virulence Genes, Biofilm Formation, and Antibiotic Resistance in Pathogenic Staphylococcus aureus from Taif Hospitals

The bacterium Staphylococcus can cause various health problems, particularly in hospitalized patients. Therefore, the current study aimed to isolate methicillin-resistant Staphylococcus aureus (MRSA) strains, test their capability to form a biofilm, and detect genes related to virulence and biofilm formation. Bacterial isolates were collected from the King Faisal Specialist Hospital and Children’s hospital in Taif Governorate, Saudi Arabia, and identified using primers for mecA and nuc1. They were tested for resistance against twelve widely distributed antibiotics and biofilm formation capability. The MRSA isolates were tested for fnbA, fnbB, and SCCmec. Among 100 isolates, 24 were identified as Staphylococcus aureus, and most of them were MRSA. Most isolates were resistant to cefrizine and cefepime (96%). The isolates showed higher resistance to amoxicillin and ampicillin (92%), followed by aztreonam (83%). Two isolates, S15 and S17, were high-grade positive for biofilm formation, 62.5% were medium-grade, and 20.8% were low-grade positive. Two of the isolates, S11 and S16, tested negative for biofilm formation. Furthermore, mecAI. ncu1 was found in all of the isolates, except S11. Most isolates had SCCmecIII and SCCmecV. All isolates were habituated to fnbB, while fnbA was not found in S3 and S11. These results indicated that PCR techniques offer rapid, simple, and accurate determination of the genetic profile and biofilm production capability of MRSA, and can be used in clinical diagnosis as well as to monitor the spread of antibiotic-resistant S. aureus strains.

Molecular identification, antimicrobial resistance and virulence gene profiling of Staphylococcus spp. associated with bovine sub-clinical mastitis in Bangladesh

This study was conducted to investigate the diversity and antimicrobial resistance profiling of Staphylococcus species causing sub-clinical mastitis (SCM) in dairy herds in Bangladesh as well as putative risk factors associated with the infections. Individual quarter milk samples were collected from a total of 284 lactating cows from 30 dairy farms were screened by means of California mastitis test; 178 (62.7%) of them had at least of quarter affected by SCM. After conventional microbiological isolation procedures, PCR tests were used for Staphylococcus species identification and detection of antimicrobial resistance and virulence genes. S. chromogenes (65.7%) was the most predominant species followed by, S. epidermidis (20.2%), S. haemolyticus (19.1%), S. aureus (15.7%), and S. sciuri (5.6%). High levels of antimicrobial resistance to ampicillin and amoxicillin/clavulanic acid were observed in S. aureus (82.1% and 75%) and S. sciuri (80% and 70%), while resistance to cefepime was markedly higher in S. chromogenes (95.7%), S. haemolyticus (94.1%), and S. epidermidis (97.2%). Multidrug resistance isolates were identified in all five species. The mecA gene was detected in S. aureus (32.1%) and S. chromogenes (5.98%). In addition, 20% S. sciuri and 17.7% S. haemolyticus carried the cytotoxin (pvl) gene, while 14.3% S. aureus harbored the toxic shock syndrome toxin (tst) gene. Multivariable logistic regression analysis identified “Old aged” (OR [CI]: 3.5 [1–12.4]); “Early stage of lactation” (OR [CI]: 3.4 [1.2–9.7]) and, “Firm udder condition” (OR [CI]: 4.2 [1.2–14.6]) as risk factors associated with SCM caused by S. aureus, S. chromogenes, and S. haemolyticus, respectively. Moreover, “Use of antimicrobials” (OR [CI]: 10.4 [3.4–32.1] and “History of previous clinical mastitis” (OR [CI]: 4.9 [1.2–19.7] for the carriage of methicillin-resistant Staphylococcus spp.

Antimicrobial Resistance and Major Virulence Gene Detection in Methicillin Resistant Staphylococcus aureus in Humans and Livestock Animals of Assam: A North Eastern State of India

Methicillin resistant Staphylococcus aureus (MRSA) is highly divergent antibiotic resistant bacteria earmarked as “High” in global pathogens’ priority list varying the severity and resistance geographically. Here, MRSA were screened using mecA gene with Cefoxitin and other 27 antibiotics of 19 classes using disc diffusion method from a highly humid climate of India. Multiple Antibiotic Resistance (MAR) index was calculated. Minimum Inhibitory Concentration (MIC) was determined against 11 classes of antibiotics. Detection of major virulence genes tst-1 and lukPV were done. A total of 95.24% Hospital Associated (HA)-MRSA, 56.14% Community Associated (CA)-MRSA and 82.53 % Livestock Associated (LA)-MRSA were detected. Cefoxitin, Oxacillin, Ciprofloxacin, Fusidic acid and Ticarcillin-Clavulinic acid resistance was observed in more than 60% of HA-MRSA, CA-MRSA and LA-MRSA. Across the hosts, Mupirocin, Gentamicin, Linezolid, Co-trimoxazole, and Rifampicin were found effective. Vancomycin Intermediate Staphylococcus aureus (VISA) detected in CA-MRSA &amp; LA-MRSA. Multidrug Resistant (MDR) was found very high but extensively drug-resistant (XDR) was detected moderately. No pan drug-resistant (PDR) was detected. Virulence gene tst-1 and lukPV were detected in 7.69% and 32.69% MRSA isolates. The gene tst-1 is reported for the first time in pre and post-caesarian samples from Gynaecology department in this region with high MDR. This study showed S. aureus and subsequent prevalence of MRSA is higher in this region then national data. 2nd generation Cephalosporins were found effective which is very encouraging due to their limited uses. Detection of tst-1 in caesarian samples is a serious threat as neonatal transmission of MRSA from mother is reported.