Detoxification of photo-catalytically treated 2-chlorophenol: optimization through response surface methodology.

The present study was conducted to degrade and detoxify 2-chlorophenol (2-CP) under UV irradiation in the presence of titanium dioxide (TiO2) and hydrogen peroxide (H2O2). The treatment efficiency was evaluated on the basis of degradation and cytotoxicity reduction as well as biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total organic carbon (TOC) removal. The process variables such as TiO2, pH, UV irradiation time and H2O2 were optimized. Central composite design in combination with response surface methodology was employed to optimize the process variables. A quadratic model was proposed to predict the treatment efficiency and analysis of variance was used to determine the significance of the variables. The correlation between the experimental and predicted degradation was confirmed by the F and P values (<0.05). The coefficient of determination (R2 = 0.99) were high enough to support the validity of developed model. At optimized conditions, up to 92% degradation of 2-CP was achieved with 3.5 × 10-4 s-1 rate constant. Significant reductions in BOD, COD and TOC values were also achieved. Cytotoxicity was evaluated using bioassays and it was observed that UV/TiO2/H2O2 reduced the cytotoxicity considerably. It is concluded that UV/TiO2/H2O2 could possibly be used to detoxify 2-CP in industrial wastewater.

Incidence and molecular characterization of extended-spectrum beta-lactamase (ESBL)-producing Salmonella enterica and Escherichia coli of avifauna origin in Pakistan.

Members of Enterobacteriaceae are known to produce extended-spectrum beta-lactamases (ESBL) which hydrolyze the beta-lactam group of antibiotics. The existence of ESBL-producing Salmonella enterica (S. enterica) and Escherichia coli (E. coli) harbored by urban avifauna was investigated in this study. Dropping samples (n= 180) were collected from six different bird species in the district Jhang, Punjab province, Pakistan. Isolation and identification of ESBL isolates were made by using cefotaxime- (4 mg/L) supplemented MacConkey agar and double disc synergy test (DDST). Polymerase chain reaction (PCR) was performed for the detection of four different ESBL genes including blaCTX-M, blaTEM, blaSHV and blaOXA. A total of 42.69% isolates were confirmed as ESBL via DDST including 30.64% S. enterica and 49.54% E. coli. The incidence of ESBL S. enterica and ESBL E. coli was found highest in egret (Ardea alba) and pigeon (Columba livia) as 64.28% and 78.95%, respectively. The blaCTX-M gene was detected in 57.89% and 64.81% of isolates of S. enterica and E. coli, respectively. Among other genes in S. enterica and E. coli, blaTEM (21.05%, 20.4%); blaSHV (15.78%, 9.26%), and blaOXA (5.26%, 5.56%) were detected, respectively. All of the tested isolates were found resistant to at least one of the thirteen antimicrobial agents except meropenem. To the best of our knowledge, this is the first study reporting the incidence and genetic diversity of ESBL bacteria associated with urban avifauna in Pakistan. The urban avifauna can serve as a potential subject of bio-surveillance to monitor the emergence of antimicrobial-resistant bacteria.

Attributable risk of Capillaria species in domestic pigeons (Columba livia domestica) / Risco atribuível de espécies Capillaria em pombos domésticos (Columba livia domestica)

Fecal samples were collected from 120 domestic pigeons to determine the Attributable risk of Capillaria spp. The Capillaria spp. was observed in 64 out of 120 (51%) pigeons (70 males and 50 females) under this study. A total of 64 (39 males and 25 females) were found naturally infected with Capillaria spp. with infection percentage of 51% and 50% in males and females respectively. Qualitative examinations include the direct microscopy and faecal floatation while quantitative examination includes McMaster technique (worms load was calculated per gram of the faeces). Month wise Attributable risk showed that eggs of the worms were found to be abundant in the month of July during the present study (60% to 73%) because of high humidity. Very high and very low temperature is not suitable for the proper development of the eggs. Qualitative and quantitative examination revealed that Capillaria spp. was more prevalent in males (51%) than females (50%) but overall there was no significant difference (P>0.05) in the male and female because both individuals invest equal amount of energy in search of food and incubating the eggs. Different breeds of pigeons gave different Attributable risk in different months during the study. Groups of pigeons from different locations showed different variable Attributable risk. Areas with high humidity were more suitable for the development of eggs, which is the reason why higher Attributable risk was observed in Shahdara (75%) area of Lahore, Pakistan.(AU)

Amostras de fezes foram coletadas de 120 pombos domésticos para determinar os fatores de risco de Capillaria spp. Capillaria spp. foi observado em 64 de 120 (51%) pombos (70 machos e 50 fêmeas) neste estudo. Um total de 64 (39 machos e 25 fêmeas) foram naturalmente infectados com Capillaria spp. sendo 51% em machos e 50% em fêmeas. Exames qualitativos incluem microscopia direta e suspensão de fezes, e exames quantitativos incluem a técnica McMaster (vermes são calculados por grama de fezes). O risco por mês demonstrou que ovos dos vermes foram encontrados em abundância no mês de Julho durante o presente estudo (60% a 73%) por causa da alta umidade. Temperaturas muito altas e muito baixas não são adequadas para o desenvolvimento adequado de ovos. O exame qualitativo e quantitativo revelou que Capillaria spp. era mais prevalente em machos (51%) que em fêmeas (50%), mas no geral não houve diferença significativa (P>0.05) entre machos e fêmeas porque ambos investem a mesma energia na busca por alimento e incubação de ovos. Diferentes raças de pombos tem diferentes riscos em diferentes meses durante o estudo. Grupos de pombos de diferentes locais demonstraram risco diferenciado. Áreas com alta umidade eram mais propensas para o desenvolvimento de ovos, o motivo pelo qual maior risco foi observado em shahdara (75%).(AU)