Molecular And Immunological Characteristics Of Vibrio Cholerae And Vibrio Alginolyticus

Twenty isolates of Vibrio cholerae and four isolates of Vibrio alginolyticus used in this study were identified using the conventional biochemical tests. All of the isolates were screened for the zonula occludens toxin gene (zot) by the Polymerase Chain Reaction (PCR) technique. The 1083 bp fragment of the zot gene was successfully amplified in all the tested isolates. Asymmetry PCR was used as a preliminary detection method and later confirmed through the gene probe method to test for the presence of the zot gene. Consequently, the zot gene was successfully cloned in pCR 2.1 TOPO vector and sequenced, in which the sequences were 99% homologous to the gene bank sequences

The exoproteomes of clonally related Staphylococcus aureus strains are diverse

Several studies have shown that protein expression patterns vary in unrelated bacterial strains due to genomic plasticity and gene regulation, resulting in enhanced heterogeneity in the infection potential. However, exoprotein expression patterns of closely related clonal strains have not been well characterized. Here, we used medium-range (pH 4–7) immobilized pH gradient–two-dimensional gel electrophoresis to investigate the exoproteome from closely related Staphylococcus aureus clonal isolates. Interestingly, we found that, under identical in vitro experimental conditions, a number of protein spots were uniquely present in samples from each clonal isolate irregardless of the similarity of the genotype and the same virulence gene profile. Only a few abundant invariant proteins were found among identical genotypic isolates. Our results clearly shown that heterogeneity in the exoproteome was present even among clonally related strains. We suggest that this heterogeneity may contribute to the degree of virulence even within one clonal genotype. The heterogeneity in the exoproteome of closely related S. aureus strains observed in the current study postulates that pre-existing antibodies are not very protective during recurrent infection with the same strain. Therefore, our findings underscore the importance of taking all clonally related strains into account during proteome analyses

Simple, time saving pulsed-field gel electrophoresis protocol for the typing of Stenotrophomonas maltophilia

We developed a time-saving and cost-efficient Pulsed Field Gel Electrophoresis (PFGE) method for the typing of Stenotrophomonas maltophilia by modifying the conventional procedures. Our modifications related to the cell suspension preparation, lysis of bacterial cells in plugs, washing steps, and consumption of restriction enzyme. Although few rapid PFGE protocols on Gram-negative bacteria are available, the use of comparatively large amounts of costly reagents prompted us to look for other alternative. Hence, by considering the speed, simplicity, and relatively low cost, the modified protocol may be of more practical value than other established protocols in investigating S. maltophilia nosocomial outbreaks

In vitro antibacterial effects of Cinnamomum extracts on common bacteria found in wound infections with emphasis on methicillin-resistant Staphylococcus aureus

Ethnopharmacological relevance: Cinnamomum species have been widely used in many traditional systems of medicine around the world. In the Malaysian traditional system of medicine, the leaves, stem bark and stem wood of Cinnamomum iners, Cinnamomum porrectum, Cinnamomum altissimum and Cinnamomum impressicostatum have been used to treat wound infections. To study the antibacterial effects of Cinnamomum iners, Cinnamomum porrectum, Cinnamomum altissimum and Cinnamomum impressicostatum against common bacteria found in wound infections with primary focus on methicillin-resistant Staphylococcus aureus (MRSA). Materials and methods: The crude extracts from the leaves, stem-bark and stem-wood of Cinnamomum iners, Cinnamomum porrectum, Cinnamomum altissimum and Cinnamomum impressicostatum were obtained using sequential extraction with hexane, ethylacetate, methanol and water. The volatile oils were obtained by hydro-distillation. The antibacterial activities of extracts were investigated using disk diffusion assays and broth microdilution assays. Results: The volatile oils obtained from the stem-bark of Cinnamomum altissimum, Cinnamomum porrectum and Cinnamomum impressicostatum have shown significant antibacterial activity against a wide range of Gram positive and Gram negative bacteria including MRSA. A few test extracts have shown better activity against MRSA as compared to methicillin sensitive Staphylococcus aureus (MSSA). Amongst all the test extracts, Cinnamomum impressicostatum stem-bark water extract produced the largest inhibition zone of 21.0 mm against MRSA while its inhibition zone against MSSA was only 8.5 mm. The minimum inhibitory concentration (MIC) of this extract against MRSA was 19.5 μg mL−1 and the corresponding minimum bactericidal concentration (MBC) was 39.0 μg mL−1. Conclusions: This study has scientifically validated the traditional use of Cinnamomum species in treating wound infections. Of high scientific interest was the observation that the antibacterial effect of Cinnamomum impressicostatum stem-bark crude water extract against MRSA was significantly higher than its effect against MSSA, suggesting that the extract contains a compound(s) with higher specific neutralising activity against the drug resistance markers of MRSA

A persistent antimicrobial resistance pattern and methicillin-resistance associated genotypes in a short term Staphylococcus aureus carriage of a student population

Background: Staphylococcus aureus is an opportunistic commensal of human anterior nares. Under favorable conditions, colonization may persist and pose significant threat in healthy individuals leading to infections. Antimicrobial treatment may be limited due to the emergence of methicillin-resistant Staphylococcus aureus (MRSA) which is also frequently resistant to a wide range of antibiotics. Objective: This study aims to assess and compare the antimicrobial sensitivity pattern and methicillin resistance-associated genotypes of carriage S. aureus previously isolated from a student population at two isolations of one-month interval. Materials and Methods: In a previous study, S. aureus was isolated from 31.3% (60/192) and 33% (60/180) of a student population during two isolations in October and November 2013 respectively (Mat Azis et al., 2014). Thirty-nine (65%) students were detected for S. aureus at both isolation events and referred as persistent carriers. All isolates were screened for MRSA by PCR detecting the mecA gene. mecA positive isolates were subjected to staphylococcal cassette chromosome (SCC) mec typing. In this current study, all 120 isolates from both isolation episodes were subjected to antibiotic susceptibility test (AST) by Kirby-Bauer disc-diffusion method against cefoxitin (30 µg), erythromycin (15 µg), vancomycin (30 µg) gentamicin (10 µg), ciprofloxacin (5 µg), rifampin (5 µg), penicillin (10 units), and tetracycline (30 µg). Isolates that showed resistant towards cefoxitin were further validated by Etest. Isolates from the 39 persistent carriers were further subjected to spa typing. Results and Conclusion: Overall, all 120 S. aureus isolates from both isolation events were susceptible toward vancomycin, ciprofloxacin and gentamycin. A highest frequency of resistance was observed for penicillin at both isolations (70% and 65% respectively). This was followed by tetracycline with a similar resistance rate (11.67%) in both isolation events. While low level of resistance was observed against erythromycin at both events. This indicates the persistence of the antimicrobial resistance pattern in the population over the short study period. As for methicillin resistance, out of the 120 isolates of S. aureus, 10 (8.33%) were positive for mecA gene with 4 and 6 isolates from first and second isolation events respectively; 2 isolates were from a same individual. However, among the mecA positive isolates, only 8 isolates showed resistance towards cefoxitin (4 isolates from each isolation event) while the other two mecA positive isolates (from second event) were cefoxitin-susceptible by both disc and Etest methods. The mecA-positive isolates belonged to SCCmec types I (n = 9) and V (n = 1). This indicates the tendency of MRSA to persist although at a low rate with limited genotypes. As for the persistent S. aureus carriers, it was found that for 19 (48.72%) of them, respective individual carried S. aureus of a similar spa types in the respective individuals over the short term period. The limitation of this study is that it only represents a short term carriage in a student population. Whether the observed findings reflect the population at large requires more studies with a longer study period and a wider population size. The incidence of mecA carrying isolates susceptible to cefoxitin requires more validation on potential heterogeneous characteristics of MRSA found in this student population

Methicillin-susceptible and -resistant Staphylococcus aureus with high-level antiseptic and low-level mupirocin resistance in Malaysia

The prevalence and spread of mupirocin and antiseptic resistance among colonizing and infectious Staphylococcus aureus were determined. S. aureus isolated from anterior nares and infection sites of patients hospitalized in the largest tertiary care referral hospital in Malaysia was investigated for mupirocin and antiseptic susceptibility testing, and for PCR detection of mupA, qacA/B, and smr genes. Twelve isolates showed resistance to mupirocin by disk diffusion, of which 10 (3.8%) harbored the mupA gene. Minimum inhibitory concentrations (MICs) ranged from 64 to 768 μg/ml for mupA positive and below 46 μg/ml for negative isolates. The mupA was more common among ST239 isolates (70%). The qacA/B was carried in 67 out of 95 methicillin-resistant Staphylococcus aureus (MRSA) (70.5%) and 3 out of 164 methicillin-susceptible Staphylococcus aureus (MSSA) (1.8%), while smr was carried in 6 out of 95 MRSA (6.3%) strains. MICs ranged from 3.9 to 15.6 μg/ml for benzethonium chloride (BTC) and benzalkonium chloride (BKC), and from 10.3 to 20.7 μg/ml for chlorhexidine digluconate (CHG). Isolates with qacA/B and smr or qacA/B alone showed higher MIC (20.7 μg/ml for CHG and 15.6 μg/ml for BTC and BKC) than the isolates that lacked antiseptic resistance genes (10.3 μg/ml for CHG and 3.9 μg/ml for BTC and BKC). In 16 cases, ST239 was isolated from the infection site and the nares simultaneously, and shared identical resistance patterns (qacAB or qacAB+smr), suggesting possible endogenous infection. Spread of low-level mupirocin resistance expressing ST239 MRSA and high-level resistance expressing emerging ST1, co-existing with antiseptic-resistant genes showing elevated MICs, should be monitored for effective infection control

Microhabitat factors influenced the prevalence of pathogenic Leptospira spp. in small mammal host

Leptospirosis, a widespread zoonotic disease, is a public health problem, especially in major urban centres, and is mainly reported to be associated with rats. In Malaysia, focus has been primarily given to the Leptospira prevalence in rodents per se, but there is lack of information on the microhabitat structure of the outbreak areas. We aimed to determine the diversity of small mammal species, microhabitat types, and their prevalence of pathogenic Leptospira spp. in the outbreak areas, which were categorized as urban, semi-urban, and recreational forests. Sampling involved deploying 100 to 300 live traps at each study site. Kidney samples were extracted from selected individuals, for screening of pathogenic Leptospira spp. by PCR. Out of 537 individuals from 15 small mammal species captured, 4 species were recorded from urban, 13 from semi-urban, and 11 from recreational forest sites. From 389 individuals screened, 58 were tested positive for pathogenic Leptospira. Recreational forests recorded the highest prevalence with 19.4% (n = 93), followed by urban, 16.6% (n = 163) and semi-urban sites with 9.8% (n = 133). Seven rodent species were tested positive for pathogenic Leptospira from all areas. R. norvegicus was found to harbour the highest prevalence (66.7%) in urban, R. rattus (53.8%) in semi-urban, whereby M. whiteheadi (44.4%) in recreational forest sites. Microhabitat analysis revealed that rubbish quantity contributed especially strongly to a high prevalence of Leptospira. This study contributes to understanding of the host and microhabitat preferences of Leptospira, which is important in controlling the spread of this disease in human's landscapes

In Vitro Anti�acterial and Anti�io�lm Activities of Chlorogenic Acid against Clinical Isolates of Stenotrophomonas maltophilia including the Trimethoprim/Sulfamethoxazole Resistant Strain

e in vitro antibacterial and antibio�lm activity of chlorogenic acid against clinical isolates of Stenotrophomonas maltophilia was investigated through disk diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), timekill and bio�lm assays. A total of 9 clinical S. maltophilia isolates including one isolate resistant to trimethoprim/sulfamethoxazole (TMP/SMX) were tested. e inhibition zone sizes for the isolates ranged from 17 to 29 mm, while the MIC and MBC values ranged from 8 to 16 g mL −1 and 16 to 32 g mL −1 . Chlorogenic acid appeared to be strongly bactericidal at 4x MIC, with a 2-log reduction in viable bacteria at 10 h. In vitro antibio�lm testing showed a 4-fold reduction in bio�lm viability at 4x MIC compared to 1x MIC values (0.085 < 0.397 A 490 nm) of chlorogenic acid. e data from this study support the notion that the chlorogenic acid has promising in vitro antibacterial and antibio�lm activities against S. maltophilia

Incidence of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in patients with urinary tract infection

CONTEXT AND OBJECTIVES: Resistant bacteria are emerging worldwide as a threat to favorable outcomes from treating common infections in community and hospital settings. The present investigation was carried out to study the incidence of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae in patients with urinary tract infection in different seasons of the year, in order to determine the prevalence of the genes blaTEM, blaSHV and blaCTX-M, which are responsible for ESBL production among ESBL-producing K. pneumoniae, in three cities in Iran, and to investigate the antimicrobial susceptibility pattern of K. pneumoniae in different seasons. DESIGN AND SETTING: Retrospective study carried out among patients with urinary tract infections in five hospitals in Iran. METHOD: Two hundred and eighty-eight clinical isolates of K. pneumoniae were collected between March 2007 and April 2008 from five hospitals in three cities in Iran. ESBLs were identified by phenotypic and genotypic methods. ESBL-producing Klebsiella pneumoniae were evaluated against non-beta-lactam antibiotics. Genes coding for ESBLs (blaSHV, TEM and CTX-M) were screened. RESULTS: Among the 288 clinical isolates of K. pneumoniae, 37.7%, 46.7% and 15.6% were obtained from hospitals in Ilam, Tehran and Tabriz, respectively, of which 39.4%, 50.7% and 45.8% were ESBL-producing K. pneumoniae in Ilam, Milad and Emam Reza hospitals, respectively. CONCLUSION: According to the results from this study, resistance to third-generation cephalosporins is higher during the cold months than during the warm months