Iranian Journal of Microbiology
Volume:10 Issue: 5, Oct 2018

Despite high prevalence of MDR-TB in India very limited information about MDR-TB and mutation patterns in rpoB, inhA and katG genes among MDR-isolates of Mycobacterium tuberculosis in south coastal Karnataka region is available; thus present study is an attempt to explore the extent of MDR-TB and mutation patterns prevalent among clinical isolates in this region using GenoType MTBDR plus assay. A total of 256 sputum samples from Pulmonary TB patients suspected of MDR-TB were tested by GenoType MTBDR plus as per manufacturer’s guidelines for detection of mutations conferring resistance to rifampicin and isoniazid. The results of GenoType MTBDR plus were recorded and analysed using SPSS version 22. For all analyses, a p value <0.05 was considered statistically significant. Fifty (19.53%) isolates were found MDR, 32 (12.50%) isolates were found mono-resistant to isoniazid and 15 (5.86%) isolates were found mono-resistant to rifampicin. Eleven isolates (4.3%) were found NTM. Mutation in codon S531L, S315T1 and C15T were most common in rpoB, katG and inhA genes respectively. Unknown mutations were found in 50.77% (33/65), 3.66% (3/82) and 26.83% (22/82) isolates for rpoB, katG and inhA genes respectively. Hetero-resistance in MDR, rifampicin monoresistant and isoniazid monoresistant isolates was found to be 26% (13/50), 20% (3/15) and 34.37% (11/32) respectively. Mutation in codon S531L, S315T1 and C15T were most common mutations associated with MDR-TB. Further high number of isolates showed mutations in unknown regions and hetero-resistance thus more elaborate studies based on sequencing are desirable in this region

Neonatal septicemia can be rapidly fatal if not treated promptly. A speedy laboratory diagnosis would improve the outcome. The BacT/ALERT 3D system (bioMerieux, Durham, North Carolina) is currently being used for laboratory diagnosis of blood stream infections. In the present study, a modified protocol was employed in which the broth was subcultured into two nutrient broth tubes and these tubes were used for biochemical tests and antimicrobial susceptibility testing to decrease the turnaround time. A prospective study was conducted in the Department of Microbiology, SDM College of Medical Sciences and Hospital, Dharwad from October 2010 to July 2012 after receiving clearance from the institutional ethics committee. Automated blood cultures of 250 neonates admitted to the Neonatal Intensive Care Unit (NICU), clinically diagnosed to have septicemia, were performed using BacT/ALERT 3D. Bottles flagged positive within 72 hours of loading were processed for identification and antibiotic susceptibility testing using a modified protocol. The results were assessed for time saved in reporting in comparison with standard protocol. Student’s t test was used for statistical analysis. Of the 250 cases studied, 117 cases yielded a positive blood culture giving a yield of 46.8%. The number of cases yielding monomicrobial growth were 73, which were included for further analysis. Of the remaining samples, 133 did not show growth, 11 were polymicrobial while 33 samples were flagged positive after 72 hours. Candida spp. grew in 34 cases, Gram negative bacilli grew in 28 cases and Gram positive cocci grew in 11 cases. In four cases, 66 hours were saved, 60 and 54 hours were saved in 18 cases each, 48 hours were saved in 27 cases, and 24 hours were saved in 6 cases. Methicillin resistant Staphylococcus aureus and Klebsiella pneumoniae were the most common isolates among Gram positive cocci and Gram negative bacilli, respectively, while C. guilliermondii was the most common Candida isolate. All Gram positive isolates were susceptible to vancomycin and linezolid. Most of the Gram negative isolates were susceptible to imipenem. This method can be employed in peripheral laboratory settings where there is no complete automation. Modification in processing blood culture can provide speedy identification and sensitivity report in blood stream infections. Time saved in reporting would play a crucial role in improving morbidity and mortality rates in neonatal septicemia.

Clostridium difficile is responsible for 15-25% of nosocomial antibiotic associated diarrhea (AAD) cases and all cases of pseudomembranous colitis. C. difficile has two major virulence factors, toxin A (enterotoxin) and toxin B (cytotoxin). The aim of this study was to determine the frequency of C. difficile strains in patients with diarrhea in Babol' hospitals with toxigenic culture and PCR assay. One hundred stool specimens were taken from diarrheal patients in hospitals of the city of Babol. All patients had a history of antibiotic use. The samples were cultured on CCFA medium. In the next stage, toxigenic culture was performed for isolated C. difficile strains. Then, PCR assay was used to identify gdh, tcdA and tcdB genes among isolated C. difficile strains. From the 100 stool samples, eight (8%) samples were positive in C. difficile culture. In toxigenic culture, two (2%) of these strains had cytopathic effects on Vero cells. All eight strains had the gdh gene. This gene is specific for C. difficile. Two strains that had cytopathic effects on toxigenic culture were positive for toxin genes. The frequency of toxigenic strains in different parts of the world is variable, and needs to be continually investigated. In the present study, the PCR method had a good correlation with toxigenic culture. Thus, it can replace the laborious and costly cell culture method

Extended-spectrum β-lactamases (ESBLs) and fluoroquinolones are generally used to treat invasive Salmonella infections, but emergence of antibiotic-resistant strains are increasing worldwide. This study was aimed to investigate the distribution of ESBLs among Salmonella serogroups isolated from pediatric patients in Tehran, Iran. The study included all Salmonella isolates recovered from pediatric patients admitted to Children’s Medical Center, Tehran, Iran during 2015-2016. Bacterial isolation and identification were performed by standard biochemical and agglutination tests. Antimicrobial susceptibility testing was done according to the Clinical and Laboratory Standards Institute (CLSI). Polymerase chain reaction was used to identify the genetic determinants responsible for ESBL phenotypes. A total of 138 S. enterica serovars were isolated from stool specimens, including serogroup A (1), serogroup B (18), serogroup C (41) and serogroup D (78). Forty isolates out of 138 Salmonella strains had shown ESBL-positive phenotype. All ESBL-positive isolates showed multiple resistant phenotype. Resistance to more than 3 antimicrobial agents was observed among ESBL-positive strains. The frequency of Salmonella strains carrying the blaCTX, blaTEM and blaSHV genes was 17 (12.3%), 40 (29.9%) and 4 (2.89%) respectively. The high rates of ESBLs positive-Salmonella strains recovered from pediatric patients is alarming and indicates a necessity to substitute the cephalosporins with a proper alternative

Antibiotic resistance in Pseudomonas aeruginosa is an increasing health problem. Integrons are associated with a variety of gene cassettes, which confer resistance to multiple classes of antibiotics. This study aimed at screening the presence of class 1, 2 and 3 integrons in P. aeruginosa in Yazd, Iran. This study was carried out on P. aeruginosa strains from March 2016 to March 2017. Clinical specimens were initially identified by the standard biochemical methods and their resistance patterns to antibiotics were studied using the disc diffusion method. PCR was carried out for the detection of class 1, 2 and 3 integrons using intI1, intI2 and intI3 gene primers, respectively. Antimicrobial susceptibility test showed that 75% of isolates were detected as multi-drug resistant (MDR), and lowest resistance was observed in ciprofloxacin (48.6%) and most resistance was in gentamicin (63.2%). Moreover, PCR results showed that 22 (15.3%) and 119 (82.6%) of P. aeruginosa isolates carried intI2 and intI1 genes, but intI3 gene was not found. Since it is customary to observe Class I integrons in P. aeruginosa isolated from clinical samples, they are often responsible for antibiotic resistance gene transfer, which calls for evaluation of integrons as contributing factors in antibiotic resistance

Listeria monocytogenes is the etiological agent of listeriosis, a highly fatal infection which causes miscarriage or stillbirth in pregnant women. The objective of this study was to detect the prevalence, serotypes, antimicrobial susceptibility and virulence factors of L. monocytogenes isolated from pregnant women with vaginitis at a tertiary care hospital in Tehran, Iran. During September 2015 to February 2017, a total of 400 vaginal swabs were collected from pregnant women. The presumptive isolates were characterized biochemically. All L. monocytogenes isolates were further analyzed by serotyping and antimicrobial susceptibility tests. All positive samples for L. monocytogenes were analyzed for presence of virulence genes (hlyA, actA, inlA, inlC, inlJ and prfA). Twenty-two (5.5%) of the samples were found positive for presence of L. monocytogenes. Most isolates are resistant to trimethoprim/sulfamethoxazole (81.82%) and chloramphenicol (54.55%). The majority of tested isolates (59.10%) belonged to serotype 4b, followed by 1/2a (22.73%), 1/2b (13.63%), and 3c (4.54%). The hlyA, actA and inlA were detected in all of the 22 L. monocytogenes isolates, but two, three and five isolates were found to lack inlC, inlJ and prfA, respectively. Only one isolate lacked three inlC, inlJ and prfA genes, and two isolates simultaneously lacked both inlJ and prfA genes. Evaluation of virulence factors and antimicrobial susceptibility can be highly helpful to develop effective treatment strategies against L. monocytogenes infections. This study is noteworthy in that it documents prevalence, virulence characteristics, and antimicrobial resistance of L. monocytogenes

Inasua is one of the traditional fermented fish products in Maluku, Indonesia. There are two types of inasua, i.e. with and without sap. The research aimed to study the succession of lactic acid bacteria (LAB) during fermentation and microbial composition in inasua. The sample of inasua was taken from two traditional producers in Layeni village, Ceram Island. The diversity of lactic acid bacteria was analyzed based on the 16S rRNA gene sequence. The succession of lactic acid bacteria was strongly influenced by the physicochemical characteristics during fermentation. Lactobacillus plantarum was found dominant in both inasuas fermentation processes. At end of fermentation, L. plantarum was still found dominant in inasua with sap while inasua without sap was dominated by Leuconostoc mesenteroides. In addition, Lactobacillus paracasei (LAB) was found only in inasua with sap. The result of Denaturing Gradient Gel Electrophoresis (DGGE) revealed that Lactobacillus was the dominant bacteria in inasua with sap while Staphylococcus was dominant in inasua without sap. Inasua with sap was found with higher bacterial diversity index and lower evenness and dominance indices, as well as more complex LAB succession pattern during fermentation and bacterial composition, as opposed to inasua without sap

Soil is rich in microbes which can be used for a variety of purposes starting from decomposition to antibiotic production. Agar-agar, extracted from the marine environment, is an important polysaccharide that has multiple uses after degradation by microbes. The aim of this study was to isolate bacteria that produced agarase enzyme, from a variety of soil sources and study their morphological and biochemical characterization. The enzyme activity of the isolates was also studied at 3 different pH, temperature and agar concentration. Agarolytic isolates, were identified from industrial and agar- enriched agriculture soil by serial dilution method using MSA media that contains agar as the only source of carbon. Qualitative analysis of the isolates was determined by iodine assay while for quantitative analysis of enzyme activity, at standard and variable conditions, DNSA method was used. Genus of SELA 4 was identified. 4 isolates were obtained from industrial soil and 6 were obtained from agriculture soil enriched with laboratory agar. Isolate ‘SELA 4’ showed maximum relative activity (OD 0.92) followed by ‘CCIL 2 (OD 0.91) under standard culture conditions. Isolate ‘SELA 1' showed maximum activity between 37°C- 40°C, pH 5-7 with 1.5% agar concentration. “CGIPL 1” showed maximum activity at pH 9 while “SELA 2” and “SELA 4” showed maximum activity at pH 5. SELA 4 belonged to genus Microbacterium (Accession no. MG203882.1). The results showed that agar degrading bacteria can also be isolated from soil sources other than the usual marine sources and can be used for the industrial production of agarase enzyme.

Antibiotics resistance has recently increased. The aim of this study was the evaluation of antibacterial efficacy of Aloe vera carrier produced in microemulsion system in comparison with ordinary antibiotics against some Enterobacteriacea. The aquatic extract of Aleo vera was produced by the Soxhlet method and a nonocarrier in the microemulsion system was prepared by two emulsifiers. The clinical isolates of Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, Shigella dysenteriae, Salmonella Typhimurium, Salmonella Paratyphi, Serratia marcescens, Proteus mirabilis, Enterobacter aerogenes, Citrobacter freundii and Morganella morganii were obtained from patients and were identified by microbiological methods. Diffusion disk was used for evaluation of antibacterial properties in comparison with selected ordinary antibiotics. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) for tested materials were determined using MTT in the Micro Broth dilution method. The results proved that effect of carrier on studied isolates is dependent on concentration level. The inhibitory effect of carrier in concentration of 15 µg/ml by 18 mm zone of inhibition for Klebsiella pneumoniae was comparable to Ceftazidime and Cefalothin. The lowest MIC and MBC determined by the Microbroth dilution method with MTT belonged to Klebsiella pneumoniae as 0.1 and 3 µg/ml and higher concentrations belonged to Enterobacter aerogenes at 7 and 15 µg/ml. The greatest effect of carrier of Aleo vera aquatic extract was observed for Klebsiella pneumoniae and the lowest effect belonged to Enterobacter aerogenes, Citrobacter freundii and Morganella morganii. It was concluded that the carrier of Aloe vera produced in microemulsion system was most effective and had equal effects in comparison with ordinary antibiotics against Enterobacteriacea

Cytomegalovirus (CMV) infection has been reported in ulcerative colitis (UC), but limited data are available on its prevalence in Iran. The aim of this study was to evaluate the prevalence of CMV infection in patients with UC. A prospective, cross-sectional study was conducted in 86 consecutive patients with UC. Prevalence of CMV infection was determined by rectal biopsies for hematoxylin and eosin staining and PCR. CMV-positive specimens was measured for CMV loads by real-time PCR assay. In six out of 86 (7%) patients with UC, CMV was diagnosed. These patients had detectable CMV DNA in their biopsies as indicated by PCR. In all CMV-positive patients, viral load was more than 250 copy/mg. Histochemical staining did not show any CMV inclusion bodies. No significant demographic and clinical differences existed between patients with and without a CMV infection. UC and its treatment may put patients at risk of CMV infection. Real-time PCR test for the detection of CMV in UC patients may enable diagnosis of CMV infection with a high sensitivity and allow effective treatment to be administered in these patients. The impact of antiviral therapy on the clinical outcome of the UC patients with CMV remains to be elucidated